固定化细胞发酵酒精研究的进展

固定化细胞发酵酒精研究的进展许苏葵，何秀良（中国科学院沈阳应用生态研究所，１１００１５）十九世纪初，人们发现某些微生物细胞具有一种吸附在固体物质表面的天然倾向和特殊功能，并以这种方式被束缚、固定起来。当时曾利用这种被吸附的微生物细胞，在滴滤式反应系统...

科尔沁沙地不同演替阶段植被特征及固沙作用

为了解不同措施对退化生态系统植被恢复的作用,采用空间代替时间的方法研究了科尔沁沙地不同演替阶段的植被变化特征,同时探讨了植被的抗风蚀及固沙作用。结果表明,人工植被恢复措施可有效提高沙丘的植被盖度和物种丰富度,多年生植物逐渐取代了一年生植物;沙丘与草场的植被相似性较差;植被的抗风蚀能力随植被盖度的增加而增加。根据目前植被的发展现状,对不同演替阶段的植被保护、管理和恢复提供了科学的指导意见。

治理水土流失 再造山川秀美延安——对中尺度生态环境建设中落实总理指示的认识与思考

通过分析黄土高原生态环境和生态建设的现状 ,进一步理解在中央决定实施西部大开发战略的新形势下 ,朱钅容基总理有关加强生态环境建设指示的重要意义。并以延安 6 5 0 km2 山川秀美示范区建设为例 ,探讨了生态环境建设的阶段、目标、模式及科技试验示范的主要任务

Critical behavior of brittle-ductile transition of polymers

We report that the brittle-ductile transition of polymers induced by temperature exhibits critical behavior. When t close to 0, the critical surface to surface interparticle distance (IDc) follows the scaling law: IDc proportional to t(-v) where t = 1 - T/T-BD(m) (T and T-BD(m) are the test temperature and brittle-ductile transition temperature of matrix polymer, respectively) and v = 2/D. It is clear that the scaling exponent v only depends on dimension (D). For 2, 3, and 4 dimension, v = 1, 2/3, and 1/2 respectively. The result indicates that the ID, follows the same scaling law as that of the correlation length (xi), when t approach to zero.

纳米级聚乙烯和聚丙烯微晶的高分辨透射电子显微学研究

用高分辨电子显微学方法对从极稀的二甲苯溶液中得到的纳米级聚乙烯 ( PE)和聚丙烯 ( PP)微晶进行了研究 ,发现这种纳米级微晶是分子堆砌不完善 ,但可以独立存在的一种亚稳态结构 ,其晶格存在着大量的弯曲、分叉、位错等缺陷 ,经热处理后有序程度大大提高 .表明高分辨电子显微学方法是研究 PE和 PP纳米级微晶的亚稳态结构和稳定性的有效手段.

Crystal structure and morphology of phenyl-capped tetraaniline in the leucoemeraldine oxidation state

A series of crystals of phenyl-capped tetraaniline in the leucoemeraldine oxidation state were obtained at different isothermal temperatures and were observed directly under transmission electron microscope. The crystals obtained at higher temperatures exhibit more perfect structures than those obtained at lower temperatures. Both the lamella thickness and the crystal size increase with crystallization temperature. The tetraaniline is apt to form larger scale crystals under lower degree of supercooling. However, their crystal structures keep steady with the crystallization temperature. The tetramer was found to adopt a monoclinic lattice with unit cell parameter of a = 13.93 angstrom, b = 8.82 angstrom, c = 23.20 angstrom, and beta = 95.03 degrees, as determined using electron diffraction tilting method combined with wide-angle X-ray diffraction experiment.

Size-affected crystallization of trans-1,4-polybutadiene

By using different catalyst systems, two trans-1,4-polybutadiene (TPBD) samples with different tr trans-content and molecular weight were synthesized. The phase transition of two samples from monoclinic form to hexagonal phase was revealed by differential calorimeter scanning and X-ray, respectively. The small-angle X-ray scattering measurements showed the remarkable discrepancy of phase transition and melting point between the two samples was attributed to the different lamellar thickness of crystals: The crystals with different crystalline morphology and lamellar thickness were developed by casting different concentration TPBD solutions. Transmission electron microscopy morphology observations proved that annealing the specimen at the temperature above the phase transition point for different times resulted in the different lamellae thickening of monoclinic form. It means that annealing the TPBD in its hexagonal phase will also slightly favor the increase of both the phase transition temperature and melting point of hexagonal phase. (C) 2001 Elsevier Science Ltd. All rights reserved.

The crystal structure and supramolecular chain of [La(NO3)(3)(OH2)(2)(phen)]center dot 15-crown-5

[La(NO3)(3)(OH2)(2)(phen)]. 15-crown-5 is hexagonal, P6(5), with a = 10.955(2), c = 43.769(9) Angstrom, and D-calc = 1.668 g cm(-3) for Z = 6. In the complex, two nitrogen atoms (from phen) and eight oxygen atoms (six from three bidentate nitrate anions and two from water molecules) are coordinated to the central La(III) ion, forming a coordination polyhedron which is approximately a bicapped square antiprism. The coordinated water molecules donate hydrogen bonds to the oxygen atoms of the crown ether, forming polymeric hydrogen bonded chains which wrap helically along the unit cell direction c.

快原子轰击质谱直接分析山核桃油中的混合甘油三酸酯

本文利用快原子轰击质谱(FABMS)直接测定山核桃油中未经任何前处理的混合甘油三酸酯,能获得其分子量和碎片结构信息,在GC和GC/MS分析的基础上。根据FABMS测得的分子量可推导出甘油三酸酯的组成和不同甘油三酸酯的含量。FABMS定量结果和GC、GC/MS测定结果及文献值相符。

SEQUENCE STRUCTURE OF ETHYLENE-VINYL SUBSTITUTED COPOLYMER WITH C-13 NMR .4.

The substituent chemical shift (SCS) has been applied to the assignment of the C-13 NMR spectrum of chlorinated polyethylene (CPE). CPE of different chlorine contents has been employed and their sequence structure discussed. The results show that characteristic of CPE with medium chlorine content is the dichloroethane structure in molecular chain. SCS parameters have been obtained from the C-13 NMR spectra. It was found that the effects of chlorine content and temperature on SCS are negligible, but the substituent parameter S1 reduced by 0.39 ppm when C2Cl4 was added to solvent ODCB.

十六烷基三甲基溴化铵水溶液热致相变的红外光谱研究

在280～320K的温度范围内考察了30％十六烷基三甲基溴化铵水溶液的红外光谱随温度的变化。结果表明该体系的凝聚胶-液晶相转变温度为300K。在300K以下的凝聚胶相,分子的极性头部基团处于高度“固定”的状态,分子的碳氢链以有序的相互平行方式排列,极性头与碳氢链之间有一定的倾斜角。在300K以上的液晶相,极性头内部CH_3-(N~+)基团以及整个极性头与碳氢链之间发生了旋转,碳氢链变为以六方亚晶胞填充形式存在,旦扭曲式构象异构体数量显著增多,极性头与碳氢链之间已不存在倾斜角,分子的亲水极性头和疏水碳氢链部分都处于“融化”状态。

Generation of internal and surface waves by seafloor movement in a two layer fluid system

Internal and surface waves generated by the deformations of the solid bed in a two layer fluid system of infinite lateral extent and uniform depth are investigated. An integral solution is developed for an arbitrary bed displacement on the basis of a linear approximation of the complete description of wave motion using a transform method (Laplace in time and Fourier in space) analogous to that used to study the generation of tsunamis by many researchers. The theoretical solutions are presented for three interesting specific deformations of the seafloor; the spatial variation of each seafloor displacement consists of a block section of the seafloor moving vertically either up or down while the time-displacement history of the block section is varied. The generation process and the profiles of the internal and surface waves for the case of the exponential bed movement are numerically illustrated, and the effects of the deformation parameters, densities and depths of the two layers on the solutions are discussed. As expected, the solutions derived from the present work include as special cases that obtained by Kervella et al. [Theor Comput Fluid Dyn 21:245-269, 2007] for tsunamis cased by an instantaneous seabed deformation and those presented by Hammack [J Fluid Mech 60:769-799, 1973] for the exponential and the half-sine bed displacements when the density of the upper fluid is taken as zero.

高原鼢鼠肌肉脂溶性物质的抗缺氧效果与化学成分

为了确定高在鼢鼠（Myospalax baileyi)体内抗缺氧水成分，通过超临界萃取（SCEF）方法从高原鼢鼠肌肉提取脂溶性部分，我们对其成分通过气相色谱－质谱（GC－MS）联用分析。为了证实高原鼢鼠肌肉脂溶性成分的抗缺氧效果，探讨其抗缺氧机制，我们以小鼠为实验动物，分为5个组，即高剂量实验组（HEG），中剂量实验组（MEG），低剂量实验组（LEG），阳性药物对照组（PEG），空白对照组（CEG），分别以浓度为20％萃取物，10％萃取物，5％萃取物，10％的红景天和蒸馏水连续饲喂10天，然后进行小鼠常压抗缺氧实验，测定小鼠血清超氧化物歧化酶（SOD），谷光甘肽过氧化物酶（GSH－PX），乳酸脱氢酶（LDH）活性及血清丙二(MAD)含量。结果发现，高原鼢鼠肌肉脂溶性物质提取率为11．5％，共确定了17种成分，主要成分是n-十六烷酸（32．293％）,n-十廿烷酸（1．109％）,n-十八烷酸（6．03％），二－羟基－环十五酮（1．198％），顺十六烯酸（6．13％），反十八烯酸（27．3％），和亚油酸（81．4％），小鼠抗缺氧实验和生化指标测试结果表明，高原鼢鼠肌从脂溶性成分在20％，10％，5％时，与空白对照组相比，都不同程度地延长小鼠在缺氧条件下的存活时间，提高小鼠血清SOD和GSH－PX活性，降低血清LDH活性，减少血清MDA含量。

甘肃鼢鼠粪尿气味对侵占行为的影响

气味是哺乳动物个体识别的主要途径，动物气味能传达个体、种、性别和优势地位等化学信息。对地面鼠个体气味识别的研究已有较多报道(Johnston et al., 1993; Johnston et al., 1994; Tang-Martinez et al., 1993)，对地下鼠气味识别研究仅见对鼹形鼠的报道(Heth et al., 1996a, 1996b; Heth et al., 1997; Todrank et al., 1996)。营地下生活的鼠类，如甘肃鼢鼠(Myospalax cansus)、鼹形鼠(Spalax ehrenbergi)等，常独居，终生栖息在自己的洞道内，从不离开并具有领域性和攻击行为。

Isolation and characterization of microsatellite DNA primers in Juniperus przewalskii Kom (Cupressaceae)

Juniperus przewalskii (Cupressaceae) is a dominant tree species endemic to the northeast Qinghai-Tibetan Plateau. This species plays an important role in maintaining the arid ecosystem in this region. However, natural distributions of this species have been declined. In order to develop effective conservation methods, it is important to know the distribution of the genetic diversity within and among populations. In this study, we developed nine new microsatellite loci for this species. We used the combining biotin capture method to enrich AG/CT/AC/GGT microsatellites. The polymorphisms of each locus were further assessed in 12 individuals from four geographically distant populations. The number of alleles per locus varied from three to six and expected heterozygosity ranged from 0.58 to 0.70. These loci together provide a useful tool to investigate the genetic diversity of this species. In addition, all markers have been crossly checked in the other four congeneric species.