低能He~(2+)与He原子碰撞转移电离出射电子能谱研究；Investigation on Electron Energy Spectra of Transfer Ionization Process in 70 and 100 keV He~(2+) Colliding on He

利用反应显微成像谱仪对70和100keV He2+与He原子碰撞转移电离(TI)过程中不同出射角度的电子能谱进行了测量,观测到出射电子能谱具有如下分布特征:出射电子速度分布介于0和入射离子速度vp之间;在不同出射角度电子能谱分布均有一极大值存在,随着出射角度的增大,能谱分布极大值逐渐减小;当电子出射角度等于45°时,多数电子集中在0eV附近。上述特征可由低能离子-原子碰撞"准分子"模型进行定性解释。在100keV He2+-He转移电离出射电子能谱中有靶电子被俘获至散射离子连续态(electron capture to continuum,简称ECC)电子的贡献,这可看做是动力学两步过程的作用。

Medium-spin states in Ge-70 and the role of the g(9/2) orbital

Medium-spin states of Ge-70 have been studied via the Ni-60(C-12,2p gamma)Ge-70 reaction at 45 MeV. The ground-state band and the second 0(+) band have been extended to the 12(+) and 8(+) states, respectively. Two negative-parity bands, one of which has a coupled structure and the other has a decoupled structure, have been observed additionally. Although the latter decoupled structure was known up to the (21(-)) state from a previous experiment, the part of the level scheme up to the 15(-) state has been largely modified by the present experiment. Backbendings observed in the positive- and negative-parity yrast bands have been compared with those of the neighboring even Ge isotopes. The experimental level structure has been compared with the shell-model calculations in the model space (2p(3/2), 1f(5/2), 2(p1/2), 1g(9/2)) employing two kinds of effective interactions, one of which is an extended P + QQ interaction with monopole interactions and the other is developed from a renormalized G matrix. Microscopic structures of the observed bands have been discussed with the help of the shell-model calculations.

Early Embryonic Exposure to Polychlorinated Biphenyls Disrupts Heat-Shock Protein 70 Cognate Expression in Zebrafish

Polychlorinated biphenyls (PCBs) are persistent environmental contaminants that have documented neurological effects in children exposed in utero. To better define neuronally linked molecular targets during early development, zebrafish embryos were exposed to Aroclor 1254, a mixture of PCB congeners that are common environmental contaminants. Microarray analysis of the zebrafish genome revealed consistent significant changes in 38 genes. Of these genes, 55% (21) are neuronally related. One gene that showed a consistent 50% reduction in expression in PCB-treated embryos was heat-shock protein 70 cognate (Hsc70). The reduction in Hsc70 expression was confirmed by real-time polymerase chain reaction (PCR), revealing a consistent 30% reduction in expression in PCB-treated embryos. Early embryonic exposure to PCBs also induced structural changes in the ventro-rostral cluster as detected by immunocytochemistry. In addition, there was a significant reduction in dorso-rostral neurite outgrowth emanating from the RoL1 cell cluster following PCB exposure. The serotonergic neurons in the developing diencephalon showed a 34% reduction in fluorescence when labeled with a serotonin antibody following PCB exposure, corresponding to a reduction in serotonin concentration in the neurons. The total size of the labeled neurons was not significantly different between treated and control embryos, indicating that the development of the neurons was not affected, only the production of serotonin within the neurons. The structural and biochemical changes in the developing central nervous system following early embryonic exposure to Aroclor 1254 may lead to alterations in the function of the affected regions.

科尔沁沙地70种草本植物个体和构件生物量比较研究

比较分析了科尔沁沙地70种草本植物盛花期时的个体和构件生物量特性。结果表明:43种植物个体生物量小于5.0 g,大部分物种根、茎、叶、花等构件的生物量均小于2.0 g,62种植物的根冠比小于1,说明70种草本植物中的大部分物种以地上生物量为主,只有少数物种具有较发达的地下根系。植物各构件生物量之间呈显著正相关,对个体生物量的贡献率为:茎>叶>根>花。多年生和1~2年生物种的个体生物量以及各构件生物量均无显著差异,但1~2年生物种的茎和地上生物量对个体生物量的贡献率显著高于多年生物种,而多年生物种的地下生物量对个体生物量的贡献率显著高于1~2年生物种,不同构件对生物量贡献率的差异有利于不同生活型植物的种群扩散和繁衍。

科尔沁沙地70种植物繁殖体形状比较研究

研究了科尔沁沙地70种植物的繁殖体(31种为种子,39种为果实)形状。用繁殖体三维(长、宽、高)的方差衡量繁殖体形状。方差越小,繁殖体越接近圆球形;方差越大,繁殖体越细长或扁平。研究结果表明,1)所量测的70种植物的繁殖体(种子或果实)形状差异很大,最小的方差不足0.03,最大的超过0.18。2)大部分一年生杂草的种子繁殖体近似于圆球形。3)黄蒿、马齿苋、碱地肤、狼尾花、灰绿藜、刺沙蓬、菟丝子、大籽蒿、狗尾草的繁殖体比较接近圆球形(方差小于0.09),它们可能具有持久种子库。4)萝摩科植物萝摩、杠柳、细叶白前繁殖体具绢毛;菊科植物女菀、飞廉、黄金菊、山莴苣、苣荬菜和夹竹桃科植物罗布麻有冠毛;石竹科植物石竹和鸢尾科植物野鸢尾有翅;香蒲科植物小香蒲有宿存花柱;可能这些植物都可被风传播。糙隐子草、披碱草、水稗草、牛鞭草、冠芒草具芒,它们可能具有固结自身的作用;苍耳、雾冰藜、鹤虱带钩或刺,易于被动物传播。5)草甸植物野豌豆、海滨天冬、小黄花菜作为传播体的种子较圆;草甸植物女菀、山莴苣、黄金菊、披碱草、野古草、牛鞭草、狼尾草作为传播体的果实扁平或细长;流沙上的先锋植物或沙生系列演替前期植物沙蓬、刺沙篷、乌丹蒿、差巴嘎蒿、狗尾草、雾冰藜、东北木蓼、山竹子等的繁殖体多数偏离圆

黄土丘陵区纸坊沟流域近70年农业生态安全评价

在国内外已有研究的基础上,结合黄土丘陵区纸坊沟流域近70a来农业生态经济系统演变过程,参考PSR模型,从生态环境、社会经济和综合功能3方面构建黄土丘陵区流域农业生态安全评价指标体系,基于层次分析法赋权的综合指数评价方法,对纸坊沟流域1938～2005年农业生态安全状况进行评价。结果表明:该流域农业生态安全状况发生了先降后升的变化,1938年处于较安全状况,1958年为极不安全状况,1975年和1985年都处于较不安全状况,1995年处于临界安全状况,2005年属于较安全状况。评价结果表明纸坊沟流域还需要进一步优化农业系统结构,实现农业生态安全。

CPE-g-HEA/TDI热塑性弹性体的制备和性能研究

采用氯化原位接枝法合成主链为氯化聚乙烯(CPE)、支链为丙烯酸-2-羟基乙酯（HEA）的官能化接枝聚合 物(CPE-g-HEA),制备CPE-g-HEA/2,4-二异氰酸甲苯酯（TDI）热塑性弹性体,并对其性能进行研究。结果表明, CPE-g-HEA/TDI热塑性弹性体的物理性能较好;与溶液法产物相比,共混法CPE-g-HEA/TDI热塑性弹性体的强度 较大、相对分子质量较小、相对分子质量分布较宽,热行为基本无变化;共混法CPE-g-HEA/TDI热塑性弹性体的反 应温度应控制在60～70℃,共混次数(即打三角包次数) 为150次时拉伸强度较高、80次时拉断伸长率较高,HEA/TDI摩尔比为1/0.5时拉伸强度较高。

Synthesis and structural characterization of a new molecule-based complex constructed from dodecamolybdophosphoric acid and imidazole

A new compound, (CH5N2)(3)(PMo12O40CH4N23H2O)-C-.-H-. (1), was synthesized and structurally characterized by elemental analyses, IR spectra, UV spectra, NMR spectra and ESR spectra. This is, to our knowledge, the first example of an imidazole-polyoxometalate species. The compound was recrystallized from N,N-dimethylformamide (DMF), and then black block-like crystals of (C3H5N2)(4)((PMoMo11O40)-Mo-V-O-VI)(.)4C(3)H(7)NO(.) 2H(2)O (2), were obtained. It crystallizes in a triclinic space group P (1) over bar with n=12.423(3) Angstrom, b=12.666(3) Angstrom, c=13.341(3) Angstrom, alpha=70.56(3)degrees, beta=71.16(3)degrees, gamma=64.18(3)degrees, V= 1742.3(6) Angstrom(3), Z=1, R1 = 0.0585, wR2 = 0.1885. An X-ray crystallographic study showed that the crystal structure is constructed by electrostatic attractions and hydrogen bonds between a dodecamolybdophosphoric anion and an imidazole. The imidazole and DMF molecules occupy cavities in a polyoxometalate lattice ordered along a c-axis. The structure of (2) is similar to that of (1) from a comparison of both IR spectra and TGA Curves.

Phase transition and transition kinetics of a thermotropic poly(amide-imide) derived from 70% pyromellitic dianhydride, 30% terephthaloyl chloride, and 1,3-bis[4-(4 '-aminophenoxy)cumyl]benzene

The phase transition and transition kinetics of a liquid crystalline copoly(amide-imide) (PAI37), which was synthesized from 70 mol% pyromellitic dianhydride, 30 mol% terephthaloyl chloride, and 1,3-bis[4-(4'-aminophenoxy)cumyl]benzene, was characterized by differential scanning calorimetry, polarized light microscopy, X-ray diffraction, and rheology. PAI37 exhibits a glass transition temperature at 182 degreesC followed by multiple phase transitions. The crystalline phase starts to melt at similar to 220 degreesC and forms smectic C (S-C) phase. The Sc phase transforms into smectic A (S-A) phase when the temperature is above 237 degreesC. The S-C to S-A transition spans a broad temperature range in which the S-A phase vanishes and forms isotropic melt. The WARD fiber pattern of PAI37 pulled from the anisotropic melt revealed an anomalous chain orientation, which was characterized by its layer normal perpendicular to the fiber direction. The transition kinetics for the mesophase and crystalline phase formation was also studied.

GAS-PHASE ACETYLATION OF C-60 AND C-70 BY ION/MOLECULE REACTIONS

Gas phase reactions of C-60 and C-70 with the ion system of acetone under chemical ionization conditions have been studied. C-60 and C-70 can react with acetyl and oxonium ions, which come from self-chemical ionization of acetone, to form adduct ions. In addition, C-60 and C-70 can accept protons to produce protonated ions. C-70 is more active in the above reactions than C-60 because of its stronger gas-phase basicity. A sigma-bond between C-60 and an acyl carbon atom can be formed to produce stable acetylated C-60 ions. The above results may be relevant to the acetylation reactions of C-60 in the condensed phase.

Gas-phase Ion-molecular Reactions of C-60 and C-70 with Acetone and Quantum Chemistry Study

Gas-phase ion-molecular reactions of C-60 and C-70 with the ion system of acetone have been studied in this paper. The ions of protoned and acetylized C-60 and C-70 were formed by the reactions of C-60 and C-70 with some ions which existed in the ion system when mass spectrometer worked on chemical ionization conditions. The reactivity of C-70 is greater than that of C-60. Results of quantum chemical calculation for the adduct ions showed a sigma bond between the acyl carbon atom and C-60 may be Formed. These results will provide some valuable informations on the condense-phase acetylization of C-60.

中性氧化铝用于碳-60、碳-70柱分离的探讨

自90年实现实验室合成C_(60)/C_(70)以来,碳原子簇化学引起世界各国科学家的广泛兴趣,纷纷开展与其相关的各项研究。由电阻加热法、电孤法产生的烟灰经过甲苯(或苯)抽提便可得到C_(60)/C_(70)混合溶液,但其大量分离却很困难。Hawkins等用苯基甘氨酸做基底的HPLC方法和Jinno等用多取代苯基修饰的二氧化硅作固

富勒烯碳-60,碳-70的电化学研究进展

短短的几年,随着各种物理与化学研究方法的相继介入,以C_(60)和C_(70)为代表的富勒烯研究取得了令人瞩目的成就。跟踪最新进展,引文41篇,本文就其电化学方面的研究工作做了系统的综述。

Cloning, sequencing and expression analysis of cDNA encoding a constitutive heat shock protein 70 (HSC70) in Fenneropenaeus chinensis

The cDNA encoding hsc70 of Chinese shrimp Fenneropenaeus chinensis was cloned from hepatopancreas by RT-PCR based on its EST sequence. The full length cDNA of 2090 bp contained an open reading frame of 1956 nucleotides and partial 5'- and 3'-untranslated region(5'- and 3'-UTR). PCR amplification and sequencing analysis showed the existence of introns in the region of 1-547 bp, but they did not exist in the region of 548-2090 bp of hsc70 cDNA. When the deduced 652 amino acid sequence of HSC70 was compared with the members of HSP70 family from other organisms, the results showed 85.9% similarity with HSC71 from Oncorhynchus mykiss and HSC70 from Homo sapiens. It also exhibited 85.8% similarity with HSP70 from Mus musculu and 85.4% with HSC70 from Manduca sexta. Expression analysis showed that hsc70 mRNA was espressed constitutively in hepatopancreas, muscle, eyestalks, haemocytes, heart, ovary, intestine and gills in Fenneropenaeus chinensis. No difference could be detected on hsc70 mRNA level in muscle between heat-shocked and control animals.