60 resultados para Parabolic Subgroup
Resumo:
高等植物种子胚乳贮藏蛋白是种子发芽时的主要氮源,也是人类和动物食用植物蛋白的主要来源。大麦种子胚乳贮藏蛋白主要是醇溶蛋白(hordeins),占大麦胚乳总蛋白的50–60%。根据大麦醇溶蛋白的大小和组成特点,大麦醇溶蛋白被划分为三种类型:富硫蛋白亚类(B,γ-hordeins)、贫硫蛋白亚类(C-hordeins)以及高分子量蛋白亚类(D-hordeins)。B组和C组醇溶蛋白是大麦胚乳的两类主要贮藏蛋白,它们分别占大麦总醇溶蛋白成分的70–80%和10–12%。遗传分析表明,大麦B、C、D和γ-组醇溶蛋白分别是由位于大麦第五染色体1H(5)上的Hor2、Hor1、Hor3和Hor5位点编码。Hor2位点编码大量分子量相同但组成不同的B组醇溶蛋白(B-hordein)。B-hordein的种类、数量和分布是影响大麦酿造、食用及饲养品质的重要因素之一。为深入了解B-hordein基因家族的结构和染色体组织,探明Hor2位点基因表达的发育调控机制,最终达到改良禾谷类作物籽粒品质的目的,本研究以青藏高原青稞为材料,采用同源克隆法,分别克隆B-hordein基因和启动子,通过原核生物表达验证B-hordein基因功能,并利用实时定量PCR探索B-hordein基因表达时空关系,取得如下研究结果: 1. 以具有特殊B组醇溶蛋白亚基组成的9份青藏高原青稞为材料,根据GenBank中三个B-hordein基因序列(GenBank No. X03103, X53690和X53691)设计一对引物,通过PCR扩增,获得23个B-hordein基因克隆并对其进行了序列分析。核苷酸序列分析表明,所有克隆均包含完整的开放阅读框。有11个克隆都存在一个框内终止密码子,推测这11个克隆可能是假基因。推测的氨基酸序列分析表明,所有大麦B-hordein具有相似的蛋白质基本结构,均包括一个高度保守的信号肽、中间重复区以及C-端结构域。不同大麦种重复区内重复基元的数目有较大差异。青稞材料Z07–2和Z26的B-hordeins仅具有12个重复基元结构,更接近于野生大麦。这些重复基元数目的差异导致了重复区序列长度和结构的变异。这种现象极可能是由于醇溶谷蛋白基因在进化过程中染色体的不平衡交换或复制滑动所造成的。对所克隆基因和禾本科代表性醇溶谷蛋白基因进行聚类分析,结果表明所有来自栽培大麦的B-hordeins聚类成一个亚家族,来自野生大麦的B-hordeins以及普通小麦的LMW-GS聚类成另外一个亚家族,表明这两个亚家族的成员存在显著差异。此外,我们发现B-hordein基因推测的C-末端序列具有一些有规律的特征:即具有相同C-末端序列的B-hordein基因在系统发生树中聚类为同一个亚组(除BXQ053,BZ09-1,BZ26-5分别单独聚为一类外)。这个特征将有助于我们对所有B组醇溶蛋白基因家族成员进行分类,避免了在SDS-PAGE电泳图谱上仅依靠大小分类的局限性。 2. 根据上述克隆的青稞B-hordein基因的5’端序列设计三条基因特异的反向引物,以青稞Z09和Z26的基因组DNA为模板,采用SON-PCR和TAIL-PCR技术分离克隆出8个B-hordein基因的上游调控序列(命名为Z09P和Z26P)。序列分析表明,推测的TATA box位于–80 bp,CAAT–like box位于–140 bp处。此外,Z09P和Z26P中有六个序列在–300 bp处均存在一个由高度保守的EM基序和类GCN4基序构成的胚乳盒(Endosperm Box,EB),在约–560 bp处存在一个胚乳盒类似结构。而Z09P-2和Z26P-3不存在保守的胚乳盒或其类似结构,预示着这两个启动子所调控的基因表达可能受不同类型反式作用因子的调节,推测该启动子对基因的表达调控具有多样性。 3. 将B-hordein基因的开放阅读框定向克隆到表达载体pET-30a中,将其导入大肠杆菌表达菌株BL21中进行外源基因的诱导表达以验证所克隆基因的功能。结果表明仅含重组子pET-BZ07-2和pET-BZ26-5的BL21细菌有目的表达蛋白产生。在诱导3 h时的蛋白表达量最高;3 mM IPTG诱导的蛋白表达量要高于1 mM IPTG诱导的表达量。这为分离纯化B-hordein蛋白以及进一步研究其对大麦籽粒品质的影响奠定基础。 4. 根据从青稞Z09和Z26中分离克隆的B-hordein基因序列设计一对基因特异的引物,同时,选择大麦α-微管蛋白基因(GenBank no. U40042)为看家基因并设计特异引物,利用实时荧光定量PCR检测了青稞籽粒4个胚乳发育时间段的B-hordein基因表达,荧光定量结果显示:两份材料中B-hordein基因的表达量均随发育过程的进行而逐渐升高。Z09中B-hordein基因在开花后7天开始转录,而Z26开花4天后就有低水平B-hordein的表达,这表明Z26中B-hordein基因可能比Z09表达的较早或者Z09中B-hordein基因表达水平较低以致于不能被检测到。此外,在4个不同的胚乳发育时期中,Z26中B-hordein基因的表达量均高于Z09材料。在开花12天到18天的过程中,Z09和Z26中B-hordein基因的表达水平有一个急剧性的升高。这说明在不同胚乳发育时期,Hor2位点的B-hordein等位基因变异体存在mRNA的差异表达。 Seed endosperm storage proteins in higher plants are the main resources of nitrogen for germinating and plant proteins for human and animals. Barley prolamins (also called hordeins) are the major storage proteins in the endosperm and account for 50–60% of total proteins. Hordeins are classically divided into three groups: sulphur-rich (B, γ-hordeins), sulphur-poor (C-hordeins) and high molecular weight (HMW, D-hordeins) hordeins based on the size and composition. B-hordeins and C-hordeins are two major groups and each respectively account for about 70-80% and 10-12% of the total hordein fraction in barley endosperm. Genetic analysis showed that B-, C-, C-, γ-hordeins are encoded by Hor2, Hor1, Hor3 and Hor5 locus on the chromosome 1H (5). Hor2 locus is rich in alleles that encode numerous heterogeneous B-hordein polypeptides. It is reported that B-hordein species, quantity and distribution are significant factors affecting malting, food and feed quality of barley. To understand comprehensively the structure and organization of B-hordein gene family in hull-less barley and explore the developmental control mechanisms of Hor2 locus gene expression and eventually to better exploitation in crop grain quality improvement, we isolated and cloned B-hordein genes and promotors of hull-less barley from Qinghai-Tibet Plateau by PCR, and testified their expression founction in bacteria expression system and explore their spatial and temporal expression pattern by quantitative real time PCR. Our results are as followed, 1. Twenty-three copies of B-hordein gene were cloned from nine hull-less barley cultivars of Qinghai-Tibet Plateau with special B-hordein subunits and molecularly characterized by PCR, based on three B-hordein genes published previously (GenBank No. X03103, X53690 and X53691). DNA sequences analyses confirmed that the six clones all contained a full-length coding region of the barley B-hordein genes. Eleven clones all contain an in-frame stop codon and they are probably pseudogenes. The analysis of deduced amino acid sequences of the genes shows that they have similar structures including signal peptide domain, central repetitive domain, and C-terminal domain. The number of the repeats was largerly variable and resulted in polypeptides in different sizes or structures among the genes. Twelve such repeated motifs were found in Z07–2 and Z26, and they are close to those of the wild barleys, and it is most probably caused by unequal crossing-over and/or slippage during replication as suggested for the evolution of other prolamins. The relatedness of prolamin genes of barley and wheat was assessed in the phylogenetic tree based on their polypeptides comparison. Our phylogenetic analysis suggested that the predicted B-hordeins of cultivated barley formed a subfamily, while the B-hordeins of wild barleys and the two most similar sequences of LMW-GS of T. aestivum formed another subfamily. This result indicated that the members of the two subfamilys have a distinctive difference. In addition, we found the B-hordeins with identical C-terminal end sequences were clustered into a same subgroup (except BXQ053,BZ09-1 and BZ26-5 as a sole group, respectively), so we believe that B-hordein gene subfamilies possibly can be classified on the basis of the conserved C-terminal end sequences of predicted polypeptide and without the limit of SDS-PAGE protein banding patterns. 2. The specific primers were designed according to the published sequences of barley B-hordein genes from Z09 and Z26. Using total DNA isolated from them as the templates, eight clones (designated Z09Pand Z26P) of upstream sequences of the known B-hordein genes was obtained by TAIL-PCR and SON-PCR. Sequences analysis shows that the putative TATA box was present at position –80 bp and CAAT-like box at position –140 bp. Besides, a putative Endosperm Box including an Endosperm Motif (EM) and a GCN4-Like Motif was found at position –300 bp in six clones, and another Endosperm-like box was found at positon –560 bp. While the Endosperm Box or Endosperm-like box was not found in Z09P-2 and Z26P-3. This may indicate that gene expression drived by the two promtors was probably controlled by different trans-acting factors and the genetic control mechanism of corresponding gene expression may be diverse. 3. The B-hordein genic region coding for the mature peptide was cloned into expression vector pET-30a and transformed into bacterial strain BL21 for identifying gene expression fountion. Protein SDS–PAGE analysis showed that only the transformed lysate with the pET-BZ07-2 and pET-BZ26-5 constructs produced proteins related to B-group hordeins of barley, and the mounts of proteins induced by 3 mM IPTG and 3 h were higher than other conditions. This established a base for isolating and putifying B-hordein and further exploring their effects on barley grain quality. 4. The gene-specific primers of B-hordein genes from Z09 and Z26 were used for the quantification of B-hordein gene expression. The α-tubulin gene from Hordeum vulgare subsp. vulgare (GenBank accession number U40042) was used as a control gene. The result shows the transcription of the B-hordein genes in Z09 was found 7 days after flowering, while the transcription of the B-hordein genes in Z26 was found 4 days after flowering, but at a very low level, and it suggested that the B-hordein genes in Z26 probably expressed earlier than those in Z09, or the B-hordein genes in Z09 expressed at so a lower level than Z26 that it can not detected. In addition, B-hordein genes in Z26 accession showed higher expression levels than those in Z09 in four developing stages. Furthermore, a progressive increase in the expression levels of the B-hordein genes between 12 and 18 days after anthesis was observed in both Z09 and Z26. It implies that the B-hordein allelic variants encoded by Hor2 locus exist the differential expression in mRNA levels of during barley endosperm development.
Resumo:
The dynamic flow profiles and column efficiencies in conically shaped semi-preparative liquid chromatographic columns (inlet ID larger than outlet ID) with two different conical angles (7degrees and 15degrees) were studied. The dynamic flow profiles were studied by an on-column visualization method. Conical columns were compared with cylindrical column of the same length and internal volume. The results showed that the flow profile of a sample band in the conical column of 7degrees (50 mm x 17 mm --> 11 mm ID) was parabolic in shape. The sample band migrated slower in the wall region than in the central region, as in the cylindrical column (50 mm x 14 mm ID). However, the sample band in the conical column of 15degrees (50 mm x 20 mm --> 7 mm ID) migrated slower in the central region than in the wall region, resulting in a reverse parabolic flow profile, in contrast to that in cylindrical column. This indicated that a flat flow profile might be realized in a conical column with a conical angle between 7degrees and 15degrees. The conical column of 15degrees had the highest column efficiency among the three columns under the same conditions. Compared with the cylindrical column packed with identical packing material, the conical column of 15degrees had 22%-45% higher column efficiency and 11%-27% higher peak height.
Resumo:
Peroxiredoxin is a superfamily of antioxidative proteins that play important roles in protecting organisms against the toxicity of reactive oxygen species (ROS). In this study, the full-length cDNA encoding peroxiredoxin 6 (designated EsPrx6) was cloned from Chinese mitten crab Eriocheir sinensis by using rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of EsPrx6 was of 1076 bp, containing a 5' untranslated region (UTR) of 69 bp, a 3' UTR of 347 bp with a poly (A) tail, and an open reading frame (ORF) of 660 bp encoding a polypeptide of 219 amino acids with the predicted molecular weight of 24 kDa. The conserved Prx domain, AhpC domain and the signature of peroxidase catalytic center identified in EsPrx6 strongly suggested that EsPrx6 belonged to the 1-Cys Prx subgroup. Quantitative real-time RT-PCR was employed to assess the mRNA expression of EsPrx6 in various tissues and its temporal expression in haemocytes of crabs challenged with Listonella anguillarum. The mRNA transcript of EsPrx6 could be detected in all the examined tissues with highest expression level in hepatopancreas. The expression level of EsPrx6 in haemocytes was down-regulated after bacterial challenge and significantly decreased compared to the control group at 12 h. As time progressed, the expression level began to increase but did not recover to the original level during the experiment. The results suggested the involvement of EsPrx6 in responses against bacterial infection and further highlighted its functional importance in the immune system of E sinensis. (C) 2009 Elsevier Ltd. All rights reserved.
Resumo:
MEP is a member of thioester-containing protein (TEP) family found in Zhikong scallop Chlamys farreri and is involved in innate immunity against invading microbes. In the present study, the genomic DNA of CfTEP was cloned and characterized. The genomic DNA sequence of CfTEP consisted of 40 exons and 39 introns spanning 35 kb with all exon-intron junction sequences agreeing with the GT/AG consensus. The genomic organization of CfTEP was similar to human and mouse 0 rather than ciona C3-1 and Drosophila dTEP2. By RT-PCR technique, seven different cDNA variants of CfTEP (designated as CfTEP-A-CfTEP-G) were cloned from scallop gonad. CfTEP-A-CfTEP-F were produced by alternative splicing of six mutually exclusive exons (exons 19-24), respectively, which encoded the highly variable central region. While in CfTEP-G, the deletion of all the six exons introduced a new translation stop site and might trigger nonsense mediated decay (NMD). The mRNA expression and the proportion of the seven CfTEP variant transcripts were examined in the gonad of scallops after bacterial challenge. The fragments containing the highly variable central region of UTEP were amplified by RT-PCR and a 100 positive clones were sequenced randomly. The expression profiles of the seven MEP variants were different and displayed the sex and bacteria dependent manner. In the blank, sea water and Listonella anguillarum challenged subgroups of male scallops, all the transcripts detected were CfTEP-G isoform. In the Micrococcus luteus challenged subgroup, the isoforms expressed and their proportions were CfTEP-F (54%), CfTEP-B (23%), CfTEP-A (10%), CfTEP-C (7%) and CfTEP-E (6%). However, in the gonad of female scallops, only CfTEP-A were found in blank and sea water challenged subgroups. After L anguillarum or M. luteus challenge, four and five isoforms were detected, respectively, with CfTEP-F isoform being the most one in the both subgroups. These results suggested that the evolution of TEP genes was very complex, and that the diverse CfTEP transcripts generated by alternative splicing played an important role as pattern recognition receptors in the innate immune defense of scallops. (C) 2009 Elsevier Ltd. All rights reserved.
Resumo:
Apoptosis is an active process of cell death, which is an integral part of growth and development in multicellular organisms. The defender against cell death 1 (DAD1), the regulatory protein to inhibit the apoptosis process, was first cloned from the bay scallop Argopecten irradians by randomly sequencing a whole tissue cDNA library and rapid amplification of cDNA end (RACE). The full-length cDNA of the A. irradians DAD1 was 607 bp, consist of a 5'-terminal untranslated region (UTR) of 63 bp, a 3'-terminal UTR of 205 bp with a canonical polyadenylation signal sequence AATAAA and a poly (A) tail, and an open reading frame of 339 bp. The deduced amino acid sequence of the A. irradians DAD1 showed 75.5% identity to Araneus ventricosus, 74.5% to Drosophila melanogaster, and 73.6% to Homo sapiens, Sus scrofa, Mesocricetus auratus, Rattus norvegicus and Mus musculus. Excluding the Saccharomyces cerevisiae DAD1 homologue, all animal DAD1 including A. irradians DAD1 homologue formed a subgroup and all plant DAD1 proteins formed another subgroup in the phylogenetic analysis. The A. irradians DAD1 was expressed in all examined tissues including adductor muscle, mantle, gills, digestive gland, gonad and hemolymph, suggesting that A. irradians DAD1 is expressed in most body tissues. Furthermore, the mRNA expression levels of A. irradians DAD1 gene of hemolymph were particularly high after injury, suggesting that the gene is responsive to injury stimuli.
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For some species, hereditary factors have great effects on their population evolution, which can be described by the well-known Volterra model. A model developed is investigated in this article, considering the seasonal variation of the environment, where the diffusive effect of the population is also considered. The main approaches employed here are the upper-lower solution method and the monotone iteration technique. The results show that whether the species dies out or not depends on the relations among the birth rate, the death rate, the competition rate, the diffusivity and the hereditary effects. The evolution of the population may show asymptotic periodicity, provided a certain condition is satisfied for the above factors. (c) 2006 Elsevier Ltd. All rights reserved.
Resumo:
I address of reconstruction of spatial irregular sampling seismic data to regular grids. Spatial irregular sampling data impairs results of prestack migration, multiple attenuations, spectra estimation. Prestack 5-D volumes are often divided into sub-sections for further processing. Shot gathers are easy to obtain from irregular sampling volumes. My strategy for reconstruction is as follows: I resort irregular sampling gathers into a form of easy to bin and perform bin regularization, then utilize F-K inversion to reconstruct seismic data. In consideration of poor ability of F-K regularization to fill in large gaps, I sort regular sampling gathers to CMP and proposed high-resolution parabolic Radon transform to interpolate data and extrapolate offsets. To strong interfering noise--multiples, I use hybrid-domain high-resolution parabolic Radon transform to attenuate it. F-K regularization demand ultimately for lower computing costs. I proposed several methods to further improve efficiency of F-K inversion: first I introduce 1D and 2D NFFT algorithm for a rapid calculation of DFT operators; then develop fast 1D and 2D CG method to solve least-square equations, and utilize preconditioner to accelerate convergence of CG iterations; what’s more, I use Delaunay triangulation for weight calculation and use bandlimit frequency and varying bandwidth technique for competitive computation. Numerical 2D and 3D examples are offered to verify reasonable results and more efficiency. F-K regularization has poor ability to fill in large gaps, so I rearrange data as CMP gathers and develop hybrid-domain high-resolution parabolic Radon transforms which be used ether to interpolate null traces and extrapolate near and far offsets or suppress a strong interfere noise: multiples. I use it to attenuate multiples to verify performances of our algorithm and proposed routines for industrial application. Numerical examples and field data examples show a nice performance of our method.
Resumo:
At present, in order to image complex structures more accurately, the seismic migration methods has been developed from isotropic media to the anisotropic media. This dissertation develops a prestack time migration algorithm and application aspects for complex structures systematically. In transversely isotropic media with a vertical symmetry axis (VTI media), the dissertation starts from the theory that the prestack time migration is an approximation of the prestack depth migration, based on the one way wave equation and VTI time migration dispersion relation, by combining the stationary-phase theory gives a wave equation based VTI prestack time migration algorithm. Based on this algorithm, we can analytically obtain the travel time and amplitude expression in VTI media, as while conclude how the anisotropic parameter influence the time migration, and by analyzing the normal moveout of the far offset seismic data and lateral inhomogeneity of velocity, we can update the velocity model and estimate the anisotropic parameter model through the time migration. When anisotropic parameter is zero, this algorithm degenerates to the isotropic time migration algorithm naturally, so we can propose an isotopic processing procedure for imaging. This procedure may keep the main character of time migration such as high computational efficiency and velocity estimation through the migration, and, additionally, partially compensate the geometric divergence by adopting the deconvolution imaging condition of wave equation migration. Application of this algorithm to the complicated synthetic dataset and field data demonstrates the effectiveness of the approach. In the dissertation we also present an approach for estimating the velocity model and anisotropic parameter model. After analyzing the velocity and anisotropic parameter impaction on the time migration, and based on the normal moveout of the far offset seismic data and lateral inhomogeneity of velocity, through migration we can update the velocity model and estimate the anisotropic parameter model by combining the advantages of velocity analysis in isotropic media and anisotropic parameter estimation in VTI media. Testing on the synthetic and field data, demonstrates the method is effective and very steady. Massive synthetic dataset、2D sea dataset and 3D field datasets are used for VTI prestack time migration and compared to the stacked section after NMO and prestack isotropic time migration stacked section to demonstrate that VTI prestack time migration method in this paper can obtain better focusing and less positioning errors of complicated dip reflectors. When subsurface is more complex, primaries and multiples could not be separated in the Radon domain because they can no longer be described with simple functions (parabolic). We propose an attenuating multiple method in the image domain to resolve this problem. For a given velocity model,since time migration takes the complex structures wavefield propagation in to account, primaries and multiples have different offset-domain moveout discrepancies, then can be separated using techniques similar to the prior migration with Radon transform. Since every individual offset-domain common-reflection point gather incorporates complex 3D propagation effects, our method has the advantage of working with 3D data and complicated geology. Testing on synthetic and real data, we demonstrate the power of the method in discriminating between primaries and multiples after prestack time migration, and multiples can be attenuated in the image space considerably.
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With the great development of Tianjing New Coastal District economy, people need more land to build and live. Land subsidence, which is caused by its special engineering geological conditions, has restricted the further development in the district. Soft soil consolidation is main factor of land subsidence ;thus , on the basis of consolidation theory, the paper make further study on soft soils one-dimension nonlinear consolidation which contains two parts:(1) the nonlinear consolidation of permeability coefficient and compressibility coefficient changing with time and depth, which means real one-dimension nonlinear consolidation;(2) the non-homogeneous consolidation of permeability coefficient and compressibility coefficient only changing with depth. Firstly, nonlinear characteristics of soft soils are elaborated. Hypoplastic theory is introduced to establish a modified soft soils nonlinear constitutive model; the nonlinear governing equation of compressibility coefficient is built, and the nonlinear characteristics of compressibility coefficient are analyzed. Secondly, Considering Load Fluctuation and soil thickness changing ,the consolidation characteristics of single layer is discussed in the paper; meanwhile, on the basis of the Davis and Raymond’s hypothesis and single layer nonlinear consolidation equation, the doubled-layer one-dimension nonlinear consolidation equation is also derived. The solution of the equation is obtained by analytical method, and the consolidation characteristics of doubled-layer soft soil nonlinear theory is also analyzed. Finally, based on assumption that permeability coefficient and compressibility coefficient is varying along depth, single layer soil one-dimension non-homogeneous consolidation differential equation is derived; and the approximate solution is obtained. Furthermore, the single layer non-homogeneous consolidation is extended to double layer non-homogeneous consolidation theory. By using parabolic differential scheme, the matrix equation is established; and the solution of the matrix equation is obtained by chase method. Consolidation characteristics of soil soft single (double) layer non-homogeneous consolidation theory and Terzaghi’s theory are also discussed.
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The processes of seismic wave propagation in phase space and one way wave extrapolation in frequency-space domain, if without dissipation, are essentially transformation under the action of one parameter Lie groups. Consequently, the numerical calculation methods of the propagation ought to be Lie group transformation too, which is known as Lie group method. After a fruitful study on the fast methods in matrix inversion, some of the Lie group methods in seismic numerical modeling and depth migration are presented here. Firstly the Lie group description and method of seismic wave propagation in phase space is proposed, which is, in other words, symplectic group description and method for seismic wave propagation, since symplectic group is a Lie subgroup and symplectic method is a special Lie group method. Under the frame of Hamiltonian, the propagation of seismic wave is a symplectic group transformation with one parameter and consequently, the numerical calculation methods of the propagation ought to be symplectic method. After discrete the wave field in time and phase space, many explicit, implicit and leap-frog symplectic schemes are deduced for numerical modeling. Compared to symplectic schemes, Finite difference (FD) method is an approximate of symplectic method. Consequently, explicit, implicit and leap-frog symplectic schemes and FD method are applied in the same conditions to get a wave field in constant velocity model, a synthetic model and Marmousi model. The result illustrates the potential power of the symplectic methods. As an application, symplectic method is employed to give synthetic seismic record of Qinghai foothills model. Another application is the development of Ray+symplectic reverse-time migration method. To make a reasonable balance between the computational efficiency and accuracy, we combine the multi-valued wave field & Green function algorithm with symplectic reverse time migration and thus develop a new ray+wave equation prestack depth migration method. Marmousi model data and Qinghai foothills model data are processed here. The result shows that our method is a better alternative to ray migration for complex structure imaging. Similarly, the extrapolation of one way wave in frequency-space domain is a Lie group transformation with one parameter Z and consequently, the numerical calculation methods of the extrapolation ought to be Lie group methods. After discrete the wave field in depth and space, the Lie group transformation has the form of matrix exponential and each approximation of it gives a Lie group algorithm. Though Pade symmetrical series approximation of matrix exponential gives a extrapolation method which is traditionally regarded as implicit FD migration, it benefits the theoretic and applying study of seismic imaging for it represent the depth extrapolation and migration method in a entirely different way. While, the technique of coordinates of second kind for the approximation of the matrix exponential begins a new way to develop migration operator. The inversion of matrix plays a vital role in the numerical migration method given by Pade symmetrical series approximation. The matrix has a Toepelitz structure with a helical boundary condition and is easy to inverse with LU decomposition. A efficient LU decomposition method is spectral factorization. That is, after the minimum phase correlative function of each array of matrix had be given by a spectral factorization method, all of the functions are arranged in a position according to its former location to get a lower triangular matrix. The major merit of LU decomposition with spectral factorization (SF Decomposition) is its efficiency in dealing with a large number of matrixes. After the setup of a table of the spectral factorization results of each array of matrix, the SF decomposition can give the lower triangular matrix by reading the table. However, the relationship among arrays is ignored in this method, which brings errors in decomposition method. Especially for numerical calculation in complex model, the errors is fatal. Direct elimination method can give the exact LU decomposition But even it is simplified in our case, the large number of decomposition cost unendurable computer time. A hybrid method is proposed here, which combines spectral factorization with direct elimination. Its decomposition errors is 10 times little than that of spectral factorization, and its decomposition speed is quite faster than that of direct elimination, especially in dealing with a large number of matrix. With the hybrid method, the 3D implicit migration can be expected to apply on real seismic data. Finally, the impulse response of 3D implicit migration operator is presented.
Resumo:
This paper builds the model of oil accumulation and achieves the prediction of exploration goal. It uses multiple subject means, the ways of synthetic research and the viewpoint of analyzing genesis, with the academic guidance of sedimentology, structural geology, petroleum geology and geochemistry, the basis of strata sequence frame and structural frame, the frame of "four history" - the burying history, the structural history, the filling history and the evolving history of oil, the masterstroke of hydrocarbon's generation, migration and accumulation, the aim of revealing the genetic relation between mature source rock and oil reservoir in space and time. Some achievements and viewpoints in this study are following. 1. It is proposed that the structural evolution in this area had many periods, and the structural movement of the Xiazijie group telophase formed the structural pattern for the first time. 2. The character of strata sequence in this area is divided by the character of episodic cycle firstly. The study of dividing the facies of single well and the facies of well tie is based on the data of single well. The character of sedimentary facies is con-structed initially. 3. It is believed that Jiamuhe group is the main source rock, which can supply considerable oil and gas resources for the first time. Some criterions of source rock such as the type ,the abundance in Jiamuhe group are analysed. Using the thermal history of source rock, we drawn a conclusion that the original type of source rock in Jiamuhe group is II_1-III, and the abundance achived the level of good source rock, and this set of source rock had contributed to this area. 4. The reservoir strata in this area are assessed and analysed with the reservoir evaluation. There are multi-type reservoirs, such as volcanic lava facies, sedimentary clast facies, continental belch facies. The physical property in reservoir strata is characterized by low porosity and low permeability. The study of diagenetic stage show that the diageneses in Jiamuhe group is A-Bsubage, and the reservoir room is mainly secondary corroded hollow and cleft. 5. The synthetic research on oil system in Jiamuhe group is made for the first time. The type of petroleum system is divided , and we consider that the petroleum system of Jiamuhe group is at the reliable rank. There are two critical time in oil accumulation through studying the critical time of oil accumulation : the early generation of hydrocarbon is oil, and the later is gas. 6. The mechanism of accumulation is analysed. We consider that the accu-mulation of oil in this area has many periods, and the early generated hydrocarbon is expeled by the later , and formed the character of zonal distribution in planar. 7. A bran-new model of oil and gas is proposed. Beneficial enrichment area of oil and gas is analyzed, which can be divided into three sections: Section I can be divided into two sections: I_1 and I_2. The lower subgroup of Jiamuhe is covered by the triassic layer of I_1 section. Fault zone and near the foot wall of fault are charactered with thick phase belt. Then the cover capability in this area is relatively poor, oil can migrate into triassic layer by vertical or lateral migration , and forms I_1 Kelamayi triassic oil pool consequently. The lower subgroup of Jiamuhe is covered by the triassic layer of I_2 section ,which is charactered with thin phase belt. Then the cover capability in this area is relatively good, and forms I_1 Kelamayi triassic oil pool consequently. Section II can be divided into two sections: II_1-I_(I~2). The cover of Jiamuhe group in section II_1 is the low resistivity segment in Wuerhe group, which has thin lithology and poor porosity and permeability. Oil and gas in Jiamuhe group can be covered to form beneficial accumulation area. There are some wells in this area, such as Ke 007 well, 561 well. The thick phase belt layer of Wuerhe high resistivity segment in section II_2 has unconformable relation with Jiamuhe group. The cover ability of the high resistivity segment is poor, petroleum in Jiamuhe can migrate into Wuerhe layer vertically. This area is the beneficial area for accumulating petroleum in Wuerhe layer. there are some wells in this area, such as Ke 75 well, Ke 76 well, Ke 77 well, Ke 78 well, Ke 79 well. Section III can also be divided into two sections: III_1 and III_2. Wuerhe group in section III_1 has unconformable relation with Jiamuhe group. There is thick lithology and poor cover in Wuerhe group, but the strata sequence evolution character of upper subgroup in Jiamuhe group has determined that it has lateral and vertical cover ability. thus, this area is petroleum abundant belt of jiamuhe group, which has the trap. Section III_2 is an area controled by wedgeout of Fengcheng group, Fengcheng group in this area has quite thick lithology so that It has beneficial resevoir phase belt. It can accumulate oil in itself or accept some oil in Jiamuhe group. Jiamuhe group has some oil accumulation condition in this area. Thus, section III_2 is jiamuhe-Fengcheng multiple petroleum accumulation belt, such as Ke 80 well. 8. The goal of exploration is suggested: Depositional trap or combination trap is the important aspect in later exploration. Both types of traps are the goal of the next drilling: Fault block trap in the east of 576 well and the NO. 2 fault block trap in the north of Ke 102 well It is suggested that we should study the law of oil and gas in Jiamuhe group and enhance the study of combination in forming reservoir and trap scale. We do some lithology forecast and reservoir diatropic forecast in order to know the area of oil and gas.
Resumo:
The dynamic prediction of complex reservoir development is one of the important research contents of dynamic analysis of oil and gas development. With the increase development of time, the permeabilities and porosities of reservoirs and the permeability of block reservoir at its boundaries are dynamically changing. How to track the dynamic change of permeability and porosity and make certain the permeability of block reservoir at its boundary is an important practical problem. To study developing dynamic prediction of complex reservoir, the key problem of research of dynamic prediction of complex reservoir development is realizing inversion of permeability and porosity. To realize the inversion, first of all, the fast forward and inverse method of 3-dimension reservoir simulation must be studied. Although the inversion has been widely applied to exploration and logging, it has not been applied to3-dimension reservoir simulation. Therefore, the study of fast forward and inverse method of 3-dimension reservoir simulation is a cutting-edge problem, takes on important realistic signification and application value. In this dissertation, 2-dimension and 3-dimension fluid equations in porous media are discretized by finite difference, obtaining finite difference equations to meet the inner boundary conditions by Peaceman's equations, giving successive over relaxation iteration of 3-dimension fluid equations in porous media and the dimensional analysis. Several equation-solving methods are compared in common use, analyzing its convergence and convergence rate. The alternating direction implicit procedure of 2-dimension has been turned into successive over relaxation iteration of alternating direction implicit procedure of 3-dimension fluid equations in porous media, which possesses the virtues of fast computing speed, needing small memory of computer, good adaptability for heterogeneous media and fast convergence rate. The geological model of channel-sandy reservoir has been generated with the help of stochastic simulation technique, whose cross sections of channel-sandy reservoir are parabolic shapes. This method makes the hard data commendably meet, very suit for geological modeling of containing complex boundary surface reservoir. To verify reliability of the method, theoretical solution and numerical solution are compared by simplifying model of 3-dimension fluid equations in porous media, whose results show that the only difference of the two pressure curves is that the numerical solution is lower than theoretical at the wellbore in the same space. It proves that using finite difference to solve fluid equations in porous media is reliable. As numerical examples of 3-dimension heterogeneous reservoir of the single-well and multi-well, the pressure distributions have been computed respectively, which show the pressure distributions there are clearly difference as difference of the permeabilities is greater than one order of magnitude, otherwise there are no clearly difference. As application, the pressure distribution of the channel-sandy reservoir have been computed, which indicates that the space distribution of pressure strongly relies on the direction of permeability, and is sensitive for space distributions of permeability. In this dissertation, the Peaceman's equations have been modified into solving vertical well problem and horizontal well problem simultaneously. In porous media, a 3D layer reservoir in which contain vertical wells and horizontal wells has been calculated with iteration. For channel-sandy reservoir in which there are also vertical wells and horizontal wells, a 3D transient heterogeneous fluid equation has been discretized. As an example, the space distribution of pressure has been calculated with iteration. The results of examples are accord with the fact, which shows the modification of Peaceman's equation is correct. The problem has been solved in the space where there are vertical and horizontal wells. In the dissertation, the nonuniform grid permeability integration equation upscaling method, the nonuniform grid 2D flow rate upscaling method and the nonuniform grid 3D flow rate upscaling method have been studied respectively. In those methods, they enhance computing speed greatly, but the computing speed of 3D flow rate upscaling method is faster than that of 2D flow rate upscaling method, and the precision of 3D flow rate upscaling method is better than that of 2D flow rate upscaling method. The results also show that the solutions of upscaling method are very approximating to that of fine grid blocks. In this paper, 4 methods of fast adaptive nonuniform grid upscaling method of 3D fluid equations in porous media have been put forward, and applied to calculate 3D heterogeneous reservoir and channel-sandy reservoir, whose computing results show that the solutions of nonuniform adaptive upscaling method of 3D heterogeneous fluid equations in porous media are very approximating to that of fine grid blocks in the regions the permeability or porosity being abnormity and very approximating to that of coarsen grid blocks in the other region, however, the computing speed of adaptive upscaling method is 100 times faster than that of fine grid block method. The formula of sensitivity coefficients are derived from initial boundary value problems of fluid equations in porous media by Green's reciprocity principle. The sensitivity coefficients of wellbore pressure to permeability parameters are given by Peaceman's equation and calculated by means of numerical calculation method of 3D transient anisotropic fluid equation in porous media and verified by direct method. The computing results are in excellent agreement with those obtained by the direct method, which shows feasibility of the method. In the dissertation, the calculating examples are also given for 3D reservoir, channel-sandy reservoir and 3D multi-well reservoir, whose numerical results indicate: around the well hole, the value of the sensitivity coefficients of permeability is very large, the value of the sensitivity coefficients of porosity is very large too, but the sensitivity coefficients of porosity is much less than the sensitivity coefficients of permeability, so that the effect of the sensitivity coefficients of permeability for inversion of reservoir parameters is much greater than that of the sensitivity coefficients of porosity. Because computing the sensitivity coefficients needs to call twice the program of reservoir simulation in one iteration, realizing inversion of reservoir parameters must be sustained by the fast forward method. Using the sensitivity coefficients of permeability and porosity, conditioned on observed valley erosion thickness in wells (hard data), the inversion of the permeabilities and porosities in the homogeneous reservoir, homogeneous reservoir only along the certain direction and block reservoir are implemented by Gauss-Newton method or conjugate gradient method respectively. The results of our examples are very approximating to the real data of permeability and porosity, but the convergence rate of conjugate gradient method is much faster than that of Gauss-Newton method.
Resumo:
In the increasingly enlarged exploration target, deep target layer(especially for the reservoir of lava) is a potential exploration area. As well known, the reflective energy becomes weak because the seismic signals of reflection in deep layer are absorbed and attenuate by upper layer. Caustics and multi-values traveltime in wavefield are aroused by the complexity of stratum. The ratio of signal to noise is not high and the fold numbers are finite(no more than 30). All the factors above affect the validity of conventional processing methods. So the high S/N section of stack can't always be got with the conventional stack methods even if the prestack depth migration is used. So it is inevitable to develop another kind of stack method instead. In the last a few years, the differential solution of wave equation was hold up by the condition of computation. Kirchhoff integral method rose in the initial stages of the ninetieth decade of last century. But there exist severe problems in it, which is are too difficult to resolve, so new method of stack is required for the oil and gas exploration. It is natural to think about upgrading the traditionally physic base of seismic exploration methods and improving those widely used techniques of stack. On the other hand, great progress is depended on the improvement in the wave differential equation prestack depth migration. The algorithm of wavefield continuation in it is utilized. In combination with the wavefield extrapolation and the Fresnel zone stack, new stack method is carried out It is well known that the seismic wavefield observed on surface comes from Fresnel zone physically, and doesn't comes from the same reflection points only. As to the more complex reflection in deep layer, it is difficult to describe the relationship between the reflective interface and the travel time. Extrapolation is used to eliminate caustic and simplify the expression of travel time. So the image quality is enhanced by Fresnel zone stack in target. Based on wave equation, high-frequency ray solution and its character are given to clarify theoretical foundation of the method. The hyperbolic and parabolic travel time of the reflection in layer media are presented in expression of matrix with paraxial ray theory. Because the reflective wave field mainly comes from the Fresnel Zone, thereby the conception of Fresnel Zone is explained. The matrix expression of Fresnel zone and projected Fresnel zone are given in sequence. With geometrical optics, the relationship between object point in model and image point in image space is built for the complex subsurface. The travel time formula of reflective point in the nonuniform media is deduced. Also the formula of reflective segment of zero-offset and nonzero offset section is provided. For convenient application, the interface model of subsurface and curve surface derived from conventional stacks DMO stack and prestack depth migration are analyzed, and the problem of these methods was pointed out in aspects of using data. Arc was put forward to describe the subsurface, thereby the amount of data to stack enlarged in Fresnel Zone. Based on the formula of hyperbolic travel time, the steps of implementation and the flow of Fresnel Zone stack were provided. The computation of three model data shows that the method of Fresnel Zone stack can enhance the signal energy and the ratio of signal to noise effectively. Practical data in Xui Jia Wei Zhi, a area in Daqing oilfield, was processed with this method. The processing results showed that the ability in increasing S/N ratio and enhancing the continuity of weak events as well as confirming the deep configuration of volcanic reservoir is better than others. In deeper target layer, there exists caustic caused by the complex media overburden and the great variation of velocity. Travel time of reflection can't be exactly described by the formula of travel time. Extrapolation is bring forward to resolve the questions above. With the combination of the phase operator and differential operator, extrapolating operator adaptable to the variation of lateral velocity is provided. With this method, seismic records were extrapolated from surface to any different deptlis below. Wave aberration and caustic caused by the inhomogenous layer overburden were eliminated and multi-value curve was transformed into the curve.of single value. The computation of Marmousi shows that it is feasible. Wave field continuation extends the Fresnel Zone stack's application.
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Job Burnout has been a focus of the Occupational Stress Research. As a typical,helping occupation, teacher has attracted widely attention and researches in the areas of pedagogy and psychology. The special subgroup of teacher, headmasters who are the elites of the Basic Education, is ignored. The research about principals’ Job Burnout is nearly blank after analyzing related documents and information. With the development of the society, people pay more and more attention to the education and put more demands on the headmasters, especially middle-school principals. They are required not only to be good educators, who are equipped with all the inner qualities as a teacher, but also good managers. So the main purpose of this research was to compare the principal group with ordinary teacher group, and reveal underling factors, such as background variables and psychological protection variables. A representative sample of Wenzhou middle school principals sized 192 and a sample of middle school teacher sized 302 were sampled from various schools. The educational version of burnout inventory, self consistency scale, and interpersonal trust scale were administrated to the two samples, together with some demographic variables of interest. The applicability and equivalence of the three instruments used in this study were checked. Based on well-established reliability and cross-sample congruence of measures, the difference between principals and teachers was test. Then the contributing factors were analysis gradually. The five background variables were examined one by one in the two samples separately. A multiple covariance analysis was conducted to test whether there remained any difference between these two samples on the variables of interest. Regression analysis was used to further control the effect of self harmony and interpersonal trust to test the difference between two samples. Mediating analysis was conducted to build the relationship among the three constructs. The main results of the research were stated as following: 1. The internal consistency coefficients of all the scales were good, and no difference exited between the two groups. The measurement equivalence of three instruments was established well. The measures could be applied to and comparing the two samples. 2. The self-harmony, and interpersonal trust of principals were better than the ordinary middle-school teachers. Job Burnout of principals was significant lower than teachers. 3. Demographic variables like the gender, age groups, income levels, disricts, and the type of school, were important influencing factors. The difference patterns of the variables on these five variables in two samples had similarity and distinction. 4. After controlling the background variables, there remained significant difference between principals and teachers on the variables of interest. 5. Job Burnout negatively correlated with self-harmony and interpersonal trust. That is to say,the lower the degree of self-harmony and interpersonal are, the serious of the Job Burnout is, The correlation between the self-harmony and the interpersonal trust was positive. 6. After statistically controlling the background variables and psychological variables, there still exited significant difference between two groups of this study. Also, self harmony and interpersonal trust were significant protection predictors to different aspect of job burnout. 7. Mediating analysis was conducted to the residual score of the three constructs after controlling the five variables and group membership. Self harmony partially mediated the relationship between interpersonal trust and job burnout. That is, interpersonal trust had indirect effect to burnout mediated by self harmony, also had direct effect to burnout.
Resumo:
Social dilemmas are defined as such situations in which short-term individual and long-term collective interests are at odds (Hardin, 1968; Messick & Brewer, 1983). Severe social problems lead more and more researchers to pay attention to the issue of social dilemmas. Until now, research has widely examined the factors influencing cooperation in social dilemmas, and provided solutions to social dilemmas. In the need of theory development, previous research generally simplified the situation of realistic social dilemmas. Therefore, few studies have explored the issue of cooperation in social dilemmas in an intergroup situation. On the other hand, there has been little empirical attention for such issues in countries outside of United States and Western Europe. To meet this gap, the present study grounded itself in social identity theories and examined the effect of unequal group status on behavioral decision making in social dilemmas. To this end, the study designed three experiments to examine how individuals with different group status response psychologically and behaviorally to cooperation in intragroup and intergroup social dilemmas. In experiment 1, the study examined how independent and interdependent self- construals affect cooperative behavior in an intragroup social dilemma. The results showed that when individuals were primed with interdependent (as opposed to independent) self-construal, they consistently contributed highly, regardless of context manipulation. In contrast, those primed with independent self-construal contributed less in the investment game but only when placed in a context where group members were encouraged to think about their individual (versus shared) fate. Results supported the idea that independent self-construal in a low interdependent context produces the most competitive behavior and that this effect was partially mediated by the feeling of interaction within a group. In experiment 2, the study examined how the effect of group status on different level of cooperation in a nested social dilemma was moderated by individual status, and what roles ingroup and superordinate identifications played in the above effect. Results found that individuals in higher status groups tended to allocate more to private account and less to subgroup account compared to those in lower status group; individuals in higher status groups allocated more to higher level accounts than to private account, whereas those in lower status acted in a reverse way. The results indicated that group status (compared to individual status) exerted a positive influence on behavioral decision making in social dilemmas, with higher group status contributing more to subgroup as well as collective interests. Results also found that the effect of group status and/or individual status on cooperation in social dilemmas was moderated by sex. As for individual status, results showed that the effect of individual status on subgroup interest was significantly moderated only by the combination of higher ingroup identification and lower superordinate identification. In experiment 3, the study explored how group stability and cognitive categorization interactively influenced the relationship between group status and behavioral decision making in a social dilemma. Results did not support the prediction that group status and stability interactively affected behavioral decision-making in social dilemmas. However, it was found that this relationship was moderated by which level individuals categorized themselves at. When categorization at the individual level was salient, individuals in high status group contributed more to subgroup account than those in low status group if they perceived a stable status hierarchy; whereas they contributed more to private account and less to collective account if they perceived that the status was instable. On the other hand, when categorization at the subgroup level was salient, individuals in high status group contributed less to collective account than those in low status group if they perceived that the status was stable; whereas they contributed less to private account and more to subgroup account if they perceived an instable status relation. In summary, the present study suggests that cooperation with ingroup forms the basis of social harmony, and higher status for everyone in any given group is a necessary for social development. On the other hand, individuals in higher status group tend to be more selfish once they realize that their current status hierarchy is unstable. However, activating their collective identity will to some degree increase the level of their cooperation with the collective. The study thus provides psychological explanations on how to construct group harmony and management suggestions on how to solve social conflicts.