997 resultados para 1008


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采用过硫酸铵(APS)为引发剂,将玉米淀粉与丙烯酰氧乙基三甲基氯化铵(DAC)接枝聚合,制备了一系列分子中含有阳离子季铵基团的淀粉——DAC接枝共聚物。研究了单体用量、引发剂用量、反应温度和反应时间对接枝体系阳离子度的影响,探讨了过硫酸铵引发淀粉接枝DAC共聚反应的基本规律。并用FTIR、X-ray和1H-NMR等表征手段对接枝共聚物进行了结构分析。

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Sodium polyacrylate was synthesized with acrylic acid as the monomer, and sodium bisulfate and ammonium persulfate as the initiator, by means of aqueous solution polymerization. The factors influencing the properties of moisture absorption, such as monomer concentration, dosage of initiator, and reaction temperature were systematically investigated. The experimental results indicate that the moisture-absorbing property of this polymer was better than other traditional material, such as silica gel, and molecular sieve. The best reaction condition and formula are based on the orthogonal experiment design. The optimum moisture absorbency of sodium polyacrylate reaches 1.01 g/g. The mathematical correlation of this polymer with various factors and moisture absorbency is obtained based on the multiple regression analysis. The moisture content intuitive analysis table shows that neutralization degree has the most significant influence on moisture absorbency, followed by monomer concentration and reaction temperature, while other factors have less influence.

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The solid solutions of CdYFeWO7, which are cubic pyrochlores of the type A(2)B(2)O(7), have been prepared and their structures were determined using Ab initio method. Rietveld refinement of the powder XRD data showed that CdYFeWO7 adopted cubic (Fd-3m) structure, while oxides crystallized in a defect-pyrochlore structure where both O (48f) and O'(8b) sites were partially occupied, and the frustrated cations sublattice precluded long range ordering of Fe/W in the pyrochlore structure. Charge distribution analysis also suggested incomplete occupation of different oxygen sites, thus the compound was non-stoichiometric, with the formula CdYFeW0.982O6.94, Magnetic measurements were carried out to find that Fe ions were in the high spin trivalent state. Curie Weiss paramagnetism down to similar to 5 K and the characteristic superposition between FC and ZFC suggested spin liquid rather than spin glass state.

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By solid state reaction, LiMgAlF6 and LiMgAlF6:Ln(3+) are synthetized with the ratio 120/100/110 of LiF/MgF2/AlF3, at 1008 K, in high-purity Ar stream. Their crystal structure which belongs to hexagonal system are determined by X-Ray-Diffraction (XRD). Luminescence characteristics of Ce3+, Eu3+, Tb3+ and sensitization of Ce3+ to Tb3+ in LiMgAlF6 are studied. It is shown that the sensitization of Ce3+ to Tb3+ is efficient and a bright green emission is observed.

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There are no discrete molecules of the title compound, catena-poly[{triaquaterbium-tris-beta-(p-nitro-benzoato)-O,O':O;O:O,O';O:O'-aqua(p-nitroben-zoato-O,O')terbium}-bis-mu-(p-nitrobenzoato-O:O') hydrate], [Tb2(C7H4NO4)6(H2O)5], in the crystal structure.

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近年来,生物制氢技术与废物综合治理技术相结合,在处理废物的同时获得清洁的能源。目前生物制氢技术发展的瓶颈问题是高效产氢菌种的获得。因此,本研究采用不同预处理方法对海洋污泥的产氢能力的影响进行了分析,同时分离获得多株海洋产酸产氢细菌和海洋光合产氢细菌。 采用不同预处理方法(包括酸处理、碱处理、热处理和硝酸盐处理)获得海洋产酸产氢混合菌种,且其对产氢能力的影响进行分析。结果表明在所有预处理方法中,热处理的最大产氢量最高;于是,我们研究了不同起始pH值(pH 4-10.0)和不同底物浓度对热处理产氢菌群的产氢能力的影响。结果表明热处理产氢菌群的最适起始pH值为8.0,该值与天然海水的pH值相近。这意味着该产酸产氢菌群可作为海洋有机废物处理的候选菌群。 通过富集获得两类海洋光合产氢菌群,它们分别可以利用发酵产氢的关键副产物—乙酸或丁酸作为产氢碳源。研究表明温度、光照强度、起始pH和乙酸或丁酸浓度皆对两类光合产氢菌群的生长和产氢能力皆有明显影响。此外,产酸产氢菌群和光合细菌菌群耦联放氢进行了初步研究,结果表明藕联放氢可以获得较高的产氢量和底物利用率。 建立了一种厌氧产氢细菌的快速筛选方法。采用该方法从已获得的暗发酵和光合高效产氢菌群中分别分离高效产氢菌株。结果分离纯化获得暗发酵产氢细菌61株和光合产氢细菌34株。其中12株暗发酵产氢细菌和7株光合产氢细菌产氢量相对较高。 利用海水养殖有机废水进行微生物制氢技术将微生物制氢和环境治理相结合,是集污水治理和废物利用为一体的综合技术,具有广阔的应用前景,本研究为海水养殖有机废水进行微生物制氢技术发展奠定了基础。

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为了分析香叶蒿挥发油的化学成分和进一步开发利用香叶蒿提供科学依据,本文采用水蒸气蒸馏法提取,运用气相色谱-质谱联用法对香叶蒿挥发油化学成分进行了分析,用气相色谱面积归一化法测定了各成分的相对百分含量。经毛细管色谱分离出56个峰,并鉴定出各峰所对应的化合物,其主要化学成分为桉树醇(Eucalyptol),樟脑(Camphor),孟烯醇4(Menthen-4-ol),异丁酮-2-基-苯(2-Butanone,3-phenyl),对异丁基苯酚(Phenol,4-(2-methylpropyl)等。香叶蒿挥发油中化合物含量丰富,且药用,及香料工业用的化合物含量较高,因此香叶蒿有很好的开发利用价值。

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用稀释平板法和氯仿熏蒸法研究了藏嵩草草甸、小嵩草草甸、矮嵩草草甸、禾草草甸、杂类草草甸及金露梅灌丛土壤的微生物数量、生物量及有机质的变化特征.结果表明:0~40 cm土层细菌和放线菌数量、微生物生物量碳和土壤有机质含量均以藏嵩草草甸最高,其微生物生物量及土壤有机质显著高于其它5种植被;真菌数量以金露梅灌丛最高;由表层到深层,随着土壤深度的增加以上各项指标均呈下降趋势.通径分析表明:土壤各生物环境因子之间存在着不同程度的相关性;土壤微生物数量、生物量及土壤有机质含量均与土壤水分含量存在显著的相关关系,说明土壤水分是调节高寒草甸生态系统土壤微生物代谢及物质转化的关键因子.

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利用多年定位测定的草地生产力资料及同步气象因素观测数据, 建立现实状况下光、温、水影响草地气候生产潜力模型:   Y= F1 (Q ) ·F2 (T ) ·F3 (P)    = K ∑[(-b·exp (a+ b∑t/∑tmax) )/(1+ exp (a+ b∑t/∑tmax) )2 ] 0           T < 0℃ ·[W 0/∑tmax ]·△∑t· Tö2 0·016658   0℃≤T< 20℃ 1           T ≥20℃ 在分析现实高寒草旬气候生产力分布与环境条件关系的同时, 根据该模型模拟计算未来气温升高2℃和4℃, 降水增加10% 和20% 状况下的气候生产力情景。在上述两种气候情景下, 未来草地生产力分别出现降低(10% ) 和升高(1% ) 的两种可能。气候变暖在一定程度上减少和缓和低温对高寒草甸牧草生长的不利影响, 但地表及植被的蒸散量的加大远比降水增加的快, 水分则成为牧草生长的限制因素。

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Offshore seismic exploration is full of high investment and risk. And there are many problems, such as multiple. The technology of high resolution and high S/N ratio on marine seismic data processing is becoming an important project. In this paper, the technology of multi-scale decomposition on both prestack and poststack seismic data based on wavelet and Hilbert-Huang transform and the theory of phase deconvolution is proposed by analysis of marine seismic exploration, investigation and study of literatures, and integration of current mainstream and emerging technology. Related algorithms are studied. The Pyramid algorithm of decomposition and reconstruction had been given by the Mallat algorithm of discrete wavelet transform In this paper, it is introduced into seismic data processing, the validity is shown by test with field data. The main idea of Hilbert-Huang transform is the empirical mode decomposition with which any complicated data set can be decomposed into a finite and often small number of intrinsic mode functions that admit well-behaved Hilbert transform. After the decomposition, a analytical signal is constructed by Hilbert transform, from which the instantaneous frequency and amplitude can be obtained. And then, Hilbert spectrum. This decomposition method is adaptive and highly efficient. Since the decomposition is based on the local characteristics of the time scale of data, it is applicable to nonlinear and non-stationary processes. The phenomenons of fitting overshoot and undershoot and end swings are analyzed in Hilbert-Huang transform. And these phenomenons are eliminated by effective method which is studied in the paper. The technology of multi-scale decomposition on both prestack and poststack seismic data can realize the amplitude preserved processing, enhance the seismic data resolution greatly, and overcome the problem that different frequency components can not restore amplitude properly uniformly in the conventional method. The method of phase deconvolution, which has overcome the minimum phase limitation in traditional deconvolution, approached the base fact well that the seismic wavelet is phase mixed in practical application. And a more reliable result will be given by this method. In the applied research, the high resolution relative amplitude preserved processing result has been obtained by careful analysis and research with the application of the methods mentioned above in seismic data processing in four different target areas of China Sea. Finally, a set of processing flow and method system was formed in the paper, which has been carried on in the application in the actual production process and has made the good progress and the huge economic benefit.

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The zircons from gneisses in high and ultrahigh pressure (HP-UHP) metamorphic zones of the Dabie Mountains have been studied on three aspects in this paper, including (1) radiation damage of zircon using Laser Raman spectrum; (2) genesis determination of zircons based on geochemistry; (3) temperature estimate of the HP-UHP metamorphism using Ti-in-zircon thermometer. The zircons have the full widths at half-maximum less than 15 cm-1 at the 1008 cm-1 peak, suggesting that they are well crystallized to moderately damaged. The early inherited zircons from gneisses had undergone significant annealing and recrystallization during the HP-UHP metamorphic event. The α-doses that zircons suffered were accumulated from about 200Ma, indicating that HP-UHP metamorphic rocks have been exhumed to the surface of the earth at this time. The studies from the CL images, mineral inclusions, U-Pb ages and trace elements reveal that metamorphic zircons were formed as two kinds of mechanisms: metamorphic growth and recrystallization. The zircons of metamorphic growth and recrystallization zircons that were completely equilibrated during the HP-UHP metamorphic event have been chosen to carry out for temperature estimate using the Ti-in-zircon thermometer. The result shows that the HP-UHP terrain of the Dabie Mountains can be divided into five zones with temperature gaps, suggesting that the terrain consists of tectonic slices with different metamorphic history.

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Marine sponge cell culture is a potential route for the sustainable production of sponge-derived bioproducts. Development of a basal culture medium is a prerequisite for the attachment, spreading, and growth of sponge cells in vitro. With the limited knowledge available on nutrient requirements for sponge cells, a series of statistical experimental designs has been employed to screen and optimize the critical nutrient components including inorganic salts (ferric ion, zinc ion, silicate, and NaCl), amino acids (glycine, glutamine, and aspartic acid), sugars (glucose, sorbitol, and sodium pyruvate), vitamin C, and mammalian cell medium (DMEM and RPMI 1640) using MTT assay in 96-well plates. The marine sponge Hymeniacidon perleve was used as a model system. Plackett-Burman design was used for the initial screening, which identified the significant factors of ferric ion, NaCl, and vitamin C. These three factors were selected for further optimization by Uniform Design and Response Surface Methodology (RSM), respectively. A basal medium was finally established, which supported an over 100% increase in viability of sponge cells.

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Iniciado em meados de 1995, o projeto de manejo florestal sustentado para pequenas propriedades tem como principal característica a prescrição de uma intervenção de baixo impacto sobre a floresta por meio de "métodos artesanais" de exploração de madeira, que consideram os baixos recursos materiais disponíveis pelos pequenos produtores. A primeira parte deste documento apresenta uma descrição sintetizada da metodologia utilizada. A segunda parte apresenta as etapas já executadas e seus respectivos resultados.

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BACKGROUND:In the current climate of high-throughput computational biology, the inference of a protein's function from related measurements, such as protein-protein interaction relations, has become a canonical task. Most existing technologies pursue this task as a classification problem, on a term-by-term basis, for each term in a database, such as the Gene Ontology (GO) database, a popular rigorous vocabulary for biological functions. However, ontology structures are essentially hierarchies, with certain top to bottom annotation rules which protein function predictions should in principle follow. Currently, the most common approach to imposing these hierarchical constraints on network-based classifiers is through the use of transitive closure to predictions.RESULTS:We propose a probabilistic framework to integrate information in relational data, in the form of a protein-protein interaction network, and a hierarchically structured database of terms, in the form of the GO database, for the purpose of protein function prediction. At the heart of our framework is a factorization of local neighborhood information in the protein-protein interaction network across successive ancestral terms in the GO hierarchy. We introduce a classifier within this framework, with computationally efficient implementation, that produces GO-term predictions that naturally obey a hierarchical 'true-path' consistency from root to leaves, without the need for further post-processing.CONCLUSION:A cross-validation study, using data from the yeast Saccharomyces cerevisiae, shows our method offers substantial improvements over both standard 'guilt-by-association' (i.e., Nearest-Neighbor) and more refined Markov random field methods, whether in their original form or when post-processed to artificially impose 'true-path' consistency. Further analysis of the results indicates that these improvements are associated with increased predictive capabilities (i.e., increased positive predictive value), and that this increase is consistent uniformly with GO-term depth. Additional in silico validation on a collection of new annotations recently added to GO confirms the advantages suggested by the cross-validation study. Taken as a whole, our results show that a hierarchical approach to network-based protein function prediction, that exploits the ontological structure of protein annotation databases in a principled manner, can offer substantial advantages over the successive application of 'flat' network-based methods.