903 resultados para Principle component
Resumo:
In order to raise the room temperature ionic conductivity and improve the mechanical strength of a PEO-based polymer electrolyte, a non-crystalline two-component epoxy network was synthesized by curing diglycidyl ether of polyethylene glycol (DGEPEG) with triglycidyl ether of glycerol (TGEG) in the presence of LiClO4 salt, which acts in this system as both a ring opening catalyst and a source of ionic carrier. The structure of the precursors, the curing process and the cured films have been characterized by C-13 NMR, IR, DSC and ionic conductivity measurement techniques. The electrolyte system exhibits an ionic conductivity as high as similar to 10(-5) S/cm at 25 degrees C and is mechanically self-supportable. The dependence of ionic conductivity was investigated as a function of temperature, salt content, MW of PEG segment in DGEPEG and the proportion of DGEPEG in DGEPEG/TGEG ratio.
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The correlation between mechanical relaxation and ionic conductivity was investigated in a two-component epoxy network-LiClO4 electrolyte system. The network was composed of diglycidyl ether of polyethylene glycol (DGEPEG) and triglycidyl ether of glycerol (TGEG). The effects of salt concentration, molecular weight of PEG in DGEPEG and the proportion of DGEPEG (1000) in DGEPEG/TGEG ratio on the ionic conductivity and the mechanical relaxation of the system were studied. It was found that, among the three influential factors, the former reinforces the network chains, reduces the free volume fraction and thus increases the relaxation time of the segmental motion, which in turn lowers the ionic conductivity of the specimen. Conversely, the latter two increase the free volume and thus the chain flexibility, showing an opposite effect. From the iso-free-volume plot of the shift factor log at and reduced ionic conductivity, it is noted that the plot can be used to examine the temperature dependence of segmental mobility and seems to be useful to judge whether the incorporated salt has been dissociated completely. Besides, the ionic conductivity and relaxation time at constant reference temperature are linearly correlated with each other in all the three cases. This result gives an additional experimental confirmation of the coordinated motion model of the ionic hopping with the moving polymer chain segment, which is generally used to explain the ionic conduction in non-glassy amorphous polymer electrolytes.
Resumo:
An epoxy network-LiClO4 electrolyte system was prepared from diglycidyl ether of polyethylene glycol and triglycidyl ether of glycerol, cured in the presence of LiClO4 only. Various techniques were used to characterize the chemical structure of the precursors and the correlation between the viscoelasticity and conductivity of the cured films was examined.
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Edwardsiella tarda is an important Gram-negative enteric pathogen affecting both animals and humans. It possesses a type III secretion system (T3SS) essential for pathogenesis. EseB, EseC and EseD have been shown to form a translocon complex after secretion, while EscC functions as a T3SS chaperone for EseB and EseD. In this paper we identify EscA, a protein required for accumulation and proper secretion of another translocon component, EseC. The escA gene is located upstream of eseC and the EscA protein has the characteristics of T3SS chaperones. Cell fractionation experiments indicated that EscA is located in the cytoplasm and on the cytoplasmic membrane. Mutation with in-frame deletion of escA greatly decreased the secretion of EseC, while complementation of escA restored the wild-type secretion phenotype. The stabilization and accumulation of EseC in the cytoplasm were also affected in the absence of EscA. Mutation of escA did not affect the transcription of eseC but reduced the accumulation level of EseC as measured by using an EseC-LacZ fusion protein in Ed. tarda. Co-purification and co-immunoprecipitation studies demonstrated a specific interaction between EscA and EseC. Further analysis showed that residues 31-137 of EseC are required for EseC-EscA interaction, Mutation of EseC residues 31-137 reduced the secretion and accumulation of EseC in Ed. tarda. Finally, infection experiments showed that mutations of EscA and residues 31-137 of EseC increased the LD50 by approximately 10-fold in blue gourami fish. These results indicated that EscA functions as a specific chaperone for EseC and contributes to the virulence of Ed. tarda.
Resumo:
Heart disease is one of the main factor causing death in the developed countries. Over several decades, variety of electronic and computer technology have been developed to assist clinical practices for cardiac performance monitoring and heart disease diagnosis. Among these methods, Ballistocardiography (BCG) has an interesting feature that no electrodes are needed to be attached to the body during the measurement. Thus, it is provides a potential application to asses the patients heart condition in the home. In this paper, a comparison is made for two neural networks based BCG signal classification models. One system uses a principal component analysis (PCA) method, and the other a discrete wavelet transform, to reduce the input dimensionality. It is indicated that the combined wavelet transform and neural network has a more reliable performance than the combined PCA and neural network system. Moreover, the wavelet transform requires no prior knowledge of the statistical distribution of data samples and the computation complexity and training time are reduced.
Resumo:
From 30 June to 24 September in 2003 ecosystem respiration (Re) in two alpine meadows on the Tibetan Plateau were measured using static chamber- and gas chromatography- (GC) based techniques. Simultaneously, plant removal treatments were set to partition Re into plant autotrophic respiration (Ra) and microbial heterotrophic respiration (Rh). Results indicated that Re had clear diurnal and seasonal variation patterns in both of the meadows. The seasonal variability of Re at both meadow sites was caused mainly by changes in Ra, rather than Rh. Moreover, at the Kobresia humilis meadow site (K_site), Ra and Rh accounted for 54% and 46% of Re, respectively. While at the Potentilla fruticosa scrub meadow (P_site), the counterparts accounted for 61% and 39%, respectively. T test showed that there was significant difference in Re rates between the two meadows (t = 2.387, P = 0.022). However, no significant difference was found in Rh rates, whereas a significant difference was observed in Ra rates between the two meadows. Thus, the difference in Re rate between the two meadows was mainly attributed to plant autotrophic respirations. During the growing season, the two meadows showed relatively low Q(10) values, suggesting that Re, especially Rh was not sensitive to temperature variation in the growing season. Additionally, Re and Rh at the K_site, as well as Rh at the P_site was negatively correlated with soil moisture, indicating that soil moisture would also play an important role in respirations.
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针对原地雷引信压发测试台存在的问题,提出改进方法和措施;详细介绍了改进后测试台的系统构成以及工作原理。改进前后的对比结果表明,改进型测试台实现了漏检率为0,无链条卡死现象,能够适用4种引信,且外表美观。
Resumo:
With the development of oil and gas field exploration, it becomes harder to search new reserves. So a higher demand of seismic exploration comes up. Now 3C3D seismic exploration technology has been applied in petroleum exploration domains abroad. Comparing with the traditional P-wave exploration, the seismic attributes information which provided by 3C3D seismic exploration will increase quickly. And it can derive various combined parameters. The precision of information about lithology, porosity, fracture, oil-bearing properties, etc which estimated by above parameters was higher than that of pure P-wave exploration. These advantages mentioned above lead to fast development of 3C3D seismic technology recently. Therefore, how to apply the technology in petroleum exploration field in China, how to obtain high quality seismic data, and how to process and interpret real data, become frontier topics in geophysical field nowadays, which have important practical significance in research and application. In this paper, according to the propagation properties of P-wave and converted wave, a study of 3C3D acquisition parameters design method was completed. Main parameters included: trace interval, shot interval, maximum offset, bin size, the interval of receiving lines, the interval of shooting lines, migration aperture, maximum cross line distance, etc. Their determination principle was given. The type of 3C3D seismic exploration geometry was studied. By calculating bin attributes and analyzing parameters of geometry, some useful conclusions were drawn. With the method in this paper, real geometries for continental lithology stratum gas reservoir and fractured gas reservoir were studied and determined. In the static method of multi-wave, the near surface P-wave, S-wave parameter investigation method has been advanced, and this method has been applied for the patent successfully; the near surface P-wave, S-wave parameter investigation method and the converted refraction wave first arrival static techniques have been integrally used to improve the effectiveness of converted wave static. In the aspect of converted wave procession, the rotation of horizontal component data, the calculation of converted wave common conversion bin, the residual static of converted wave, the velocity analysis of the common conversion point (CCP), the Kirchhoff pre-stack time migration of converted wave techniques have been applied for setting up the various 3C3D seismic data processing flows based on different geologic targets, and the high quality P-wave, converted-wave profiles have been acquired in the actual data processing. In the aspect of P-wave and converted-wave comprehensive interpretation, the thoughts and methods of using zero-offset S-wave VSP data to calibrate horizon have been proposed; the method of using P-wave and S-wave amplitude ratio to predict the areas of oil and gas enrichment has been studied; the method of inversion using P-wave combined with S-wave has been studied; the various P-wave, S-wave parameters(velocity ratio, amplitude ratio, poisson ratio) have been used to predict the depth, physical properties, gas-bearing properties of reservoirs; the method of predicting the continental stratum lithology gas reservoir has been built. The above techniques have all been used in various 3D3C seismic exploration projects in China, and the better effects have been gotten. By using these techniques, the 3C3D seismic exploration level has been improved.
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Conventional seismic attribute analysis is not only time consuming, but also has several possible results. Therefore, seismic attribute optimization and multi-attribute analysis are needed. In this paper, Fuyu oil layer in Daqing oil field is our main studying object. And there is much difference between seismic attributes and well logs. So under this condition, Independent Component Analysis (ICA) and Kohonen neural net are introduced to seismic attribute optimization and multi-attribute analysis. The main contents are as follows: (1) Now the method of seismic attribute compression is mainly principal component analysis (PCA). In this article, independent component analysis (ICA), which is superficially related to PCA, but much more powerful, is used to seismic reservoir characterizeation. The fundamental, algorithms and applications of ICA are surveyed. And comparation of ICA with PCA is stydied. On basis of the ne-entropy measurement of independence, the FastICA algorithm is implemented. (2) Two parts of ICA application are included in this article: First, ICA is used directly to identify sedimentary characters. Combined with geology and well data, ICA results can be used to predict sedimentary characters. Second, ICA treats many attributes as multi-dimension random vectors. Through ICA transform, a few good new attributes can be got from a lot of seismic attributes. Attributes got from ICA optimization are independent. (3) In this paper, Kohonen self-organizing neural network is studied. First, the characteristics of neural network’s structure and algorithm is analyzed in detail, and the traditional algorithm is achieved which has been used in seism. From experimental results, we know that the Kohonen self-organizing neural network converges fast and classifies accurately. Second, the self-organizing feature map algorithm needs to be improved because the result of classification is not very exact, the boundary is not quite clear and the velocity is not fast enough, and so on. Here frequency sensitive principle is introduced. Combine it with the self-organizing feature map algorithm, then get frequency sensitive self-organizing feature map algorithm. Experimental results show that it is really better. (4) Kohonen self-organizing neural network is used to classify seismic attributes. And it can be avoided drawing confusing conclusions because the algorithm’s characteristics integrate many kinds of seismic features. The result can be used in the division of sand group’s seismic faces, and so on. And when attributes are extracted from seismic data, some useful information is lost because of difference and deriveative. But multiattributes can make this lost information compensated in a certain degree.
Resumo:
To deal with the problems in multi-component converted seismic wave exploration in coal fields, the wave propagating features and imaging methods of multi-component converted waves in coal measure strata are researched in this thesis firstly. The relations between viscoelasticity and anisotropy in coal measure strata are analyzed to build KEL-TI model, and which seismic wave propagating and attenuating features are researched. The disadvantages of converted wave imaging methods based on common converted point gather are analyzed and constant velocity no NMO converted wave imaging method based on common scattering point gather is put forward, according to Huygens-Fresnel principle, which applicabilities in the elastic isotropic, elastic TI and KEL-TI situations are discussed. To different model simulation data, the common scattering point gathers’ and stacked profiles’ features are analyzed. The results show that the method can image compressional waves and converted waves with high precision. Secondly, the resolution enhancing theories and methods of converted wave are researched by Rayleigh wave suppressing, converted wave static correction and poststack inverse-Q filtering. 1) The polarization filter is designed by the instantaneous polarization information of seismic waves, and the Rayleigh wave suppressing method is researched. From the spectrum analysis before and after filtering, it can be derived that the amplitudes are kept relatively. 2) To constant velocity no NMO converted wave imaging method, the static correction method based on common equivalent offset point gather is put forward and tested to the actual converted waves. 3) The relation between equivalent quality factor of converted wave, compressional wave quality factor and the ratio of compressional to shear wave velocity is derived. The compressional wave quality inversion method by first arrivals of none-offset VSP is researched, and which is then transformed to the equivalent quality factor to perform inverse-Q filtering of actual converted waves. The result has shown that the method can recover the high frequency energy of converted waves. At last, the theories and methods researched in this thesis are practiced to the 3D3C seismic exploration in Guqiao coal mine in Huainan and achieve good results.
Resumo:
Based on the principle and method of sequence, the author describes the sequence-filling model of the rifting basin of Xujiaweizi and its gas exploration potential. The object of this paper belongs to the area around Shengping-Wangjiatun anticline. Its srtatigraphy includes Huoshiling Formation (neutral and basic volcanic rocks), Shahezi Formation (coal bedding and mud and some sandstone) and Yingcheng Formation from bottom to top. These stratigraphy units are defined by author as mesosequences respectively. The author emphasizes that the main control factors of sequence change with the types of basin and stage of basin. So the sequence is researched according to the types of basin. This viewpoint is very new, and it is consistent with the principle of sequence. Volcanic action is very frequent and acute, topography difference is obvious. Between the volcanic events, Shahezi Formation is formed, which mainly consists-of sedimentary rocks. Based on the datum from seismic section and drilling core and well-logging, the author analyzes the single unit and unit set and system tract and sedimentary fancies, then, according to the accommodation space change and marking of sequence boundary, Shahezi Formation is divided into two Third-scale sequences. The sedimentary fancies and depth distribution are described. The author also pointed out that the volcanic rocks consume the accommodation space, so volcanic rocks can influence the development of sequence. Based on the concept of accommodation space, the author put volcanic rocks into sequence frame, which normally consists of sedimentary rocks. The topography of volcanic is controlled by lithology of volcanic rocks, the pattern of volcanic eruption and the topography before volcanic eruption. The topography of volcanic can influence sedimentation and the filling pattern of sedimentary rocks. The author describes the composition and lithology fancies and depth distribution of volcanic rocks. The volcanic rocks and Volcanic building, volcanic structure is recognized on seismic section. The author paid a special attention to the relationship between sedimentation and volcanism. Finally, the author analyses the combination of source-reservoir-cover unit in sequence frame. The mudstone of Shahezi Formation has a great depth, the Kerogene in it belongs to type II and III, which tends to produce gas. The Yingcheng Formation lies between Shahezi Formation and Denglouku Formation, belonging to good reservoir. The volcanic rocks of Huoshiling Formation often formed high building, which can capture the gas produced from Shahezi Formation. The stratigraphy of rifting basin of Xujiaweizi has the great potential of gas exploration. This paper claims the following creative points: 1. The author applied the principle and method of sequence to rifting basin, greatly extending its research area and topic issues. 2. The author pointed out that basin of different type and of different stage has a different type of sequence. This is caused by the different main control factors of sequence. 3. Put volcanic rocks into the sequence frame, discussing the probability of regarding the volcanic rocks as the component of sequence, dealing with the relationship between sedimentation and volcanism and its influence to the source-reservoir-cover system. 4. The author pointed out that the filling pattern of rifting basin are determined by the filling pattern of megasequence, whose filling pattern is determined by the filling pattern of system tract and the change of accommodation space.
Resumo:
Since anxiety exists as a certain kind of relation between the subject and his stimuli, present study proposed the criterion that every one of the anxiety’s structural components had to manifest the properties of the relation, not the subject’s properties, and not the stimuli’s properties, too; and that every component must be a bridge from the subject to the object. Several structural models on anxiety were judged by the criterion, and three suited factors were drawn out, which were controllability, importance and urgency. Then through various methods of interview, questionnaire, laboratorial experiment, events graded, the research examined the relations between the three factors and normal anxiety, and explored the interaction of controllability, importance and urgency when they worked together. The results were as the following: 1. The hypothesis that controllability, importance and urgency were the structural components of normal anxiety sounds reasonable, which was supported in different degrees by the results of several secondary research with various methods. 2. With a totally different method of constructing items from the prevalent integrative anxiety inventory, an effective normal anxiety inventory of middle school students was developed based on this theoretical consideration. Reliability and validity research showed that the coefficient of homogeneity and test-retest reliability were high. The construct validity and criterion validity were good enough. The inventory was a useful scale to measure the normal anxiety for middle school students. 3. It’s through their interaction that controllability and importance effect on the level of anxiety which was produced by the relevant event. 4. Anxiety arises with the increasing of importance or urgency. Though there’s a very close connection between controllability and anxiety, the concrete situation is very complicated. Not only is the level of anxiety affected by the interaction of controllability and importance, but when controllability tends to be extremely high or extremely low, importance may also begin to vary with controllability. What’s more, dispositional optimism and self-efficacy still exert influences that cannot be ignored on the relationship between controllability and anxiety. All the results indicated that it was reasonable to regard and study anxiety as a kind of relation between the subject and his environment, and to some extent it’s even necessary if the intention was to clarify the structure of anxiety. Since all the other emotion also exists as a kind of relation between the subject and his stimuli, the wholeness principle which was first proposed and recommended in this study will be of great value to the related researchers. And the interaction between controllability and importance may suggest a valid coping strategy of anxiety.