Observation of Slow Magnetic Relaxation in Discrete Dysprosium Cubane

A discrete dysprosium cubane has been prepared and structurally characterized Slow relaxation of magnetization in this complex is observed, which may stimulate further investigations into the dynamics of magnetization in lanthanide clusters with different topologies.

A HIGH-RESOLUTION SOLID-STATE NMR AND DSC STUDY OF MISCIBILITY AND CRYSTALLIZATION BEHAVIOR OF POLY(VINYL ALCOHOL)/POLY(N-VINYL-2-PYRROLIDONE) BLENDS

Blends of crystallizable poly(vinyl alcohol) (PVA) with poly(N-vinyl-2-pyrrolidone) (PVPy) were studied by C-13 cross-polarization/magic angle spinning (CP/MAS) n.m.r. and d.s.c. The C-13 CP/MAS spectra show that the blends were miscible on a molecular level over the whole composition range studied, and that the intramolecular hydrogen bonds of PVA were broken and intermolecular hydrogen bonds between PVA and PVPy formed when the two polymers were mixed. The results of a spin-lattice relaxation study indicate that blending of the two polymers reduced the average intermolecular distance and molecular motion of each component, even in the miscible amorphous phase, and that addition of PVPy into PVA has a definite effect on the crystallinity of PVA in the blends over the whole composition range, yet there is still detectable crystallinity even when the PVPy content is as high as 80 wt%. These results are consistent with those obtained from d.s.c. studies.

A HIGH-RESOLUTION SOLID-STATE NMR-STUDY OF THE MISCIBILITY, MORPHOLOGY, AND TOUGHENING MECHANISM OF POLYSTYRENE WITH POLY(2,6-DIMETHYL-1,4-PHENYLENE OXIDE) BLENDS

An extended Goldman-Shen pulse sequence was used to observe indirectly the proton spin diffusion in the blends of polystyrene (PS) with poly(2,6-dimethyl-1,4-phenylene oxides) (PPO). The results indicate that the average distance between PS and PPO is less than 5 angstrom in the intimately mixed phase, but there are heterogeneous domains on a 100-angstrom scale. The data of spin relaxation of carbons, T1(C), for homopolymers and their blends suggest that there is a strong pi-pi electron conjugation interaction between the aromatic rings of PS and those of PPO, while the aromatic rings of PPO drive the aromatic rings of PS to move cooperatively. It is the cooperative motion that markedly improves the impact strength of PS.

碳-13核磁共振定量测定萄葡糖及果糖的含量

本文利用~(13)C-NMR方法测量由葡萄糖通过葡萄糖异构酶的作用,在不同的条件下,在转化为果糖的过程中葡萄糖和果糖的相对含量。同时~(13)C-NMR技术也是直接测定各种构型糖含量的有效方法。实验结果表明,Gd-DPTA弛予试剂能够使自旋-晶格弛豫时间(T1)缩短。同时对NOE效应的消除也作了描述。本法测定的相对误差低于±0.5％。

The complete mitochondrial genomes of two common shrimps (Litopenaeus vannamei and Fenneropenaeus chinensis) and their phylogenomic considerations

Complete mitochondrial genomes have proven extremely valuable in helping to understand the evolutionary relationships among metazoans. However, uneven taxon sampling may lead to unclear or even erroneous phylogenetic topologies. The decapod crustaceans are relatively well-sampled, but sampling is still uneven within this group. We have sequenced the mitochondrial genomes of two shrimps Litopenaeus vannamei and Fenneropenaeus chinensis. As seen in other metazoans, the genomes contain a standard set of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and an AT-rich non-coding region. The gene arrangements are consistent with the pancrustacean ground pattern. Both the pattern of gene rearrangements and phylogenomic analyses using concatenated nucleic acid and amino acid sequences of the 13 mitochondrial protein-coding genes strengthened the support that Caridea and Palinura are primitive members of Pleocyemata. These sequences, in combination with two previously published penaeid mitochondrial genomes, suggest that genera within the family Penaeidae have the following relationship: (((Penaeits + Fenneropenaett.) + Litopeiiaelts) + Marsupenaeus). The analyses of nucleic acid and amino acid sequences of the mitochondrial genomes also strongly support the monophyly of Penaeidae, Brachyura and Pleocyemata. In addition, the analyses of the average Ka/Ks in the 13 mitochondrial protein-coding genes of penaeid shrimps indicated a strong purifying selection within this group.

两种红树林植物黄槿和长梗肖槿化学成分研究

由于红树林植物的重要药用价值及其特殊的生长环境，越来越多的学者关注于红树林植物的活性成分及其作用机理的研究。本论文对两种药用红树林植物黄槿（Hibiscus tiliaceus L.）和长梗肖槿（Thespesia populneoides (Roxb.) Kostel）的化学成分进行了系统研究。对从其中分离得到的部分化合物进行了初步的抗菌活性筛选。 黄槿和长梗肖槿均采自海南岛，干燥粉碎的样品用90％的乙醇水以及1：1氯仿-甲醇混合溶液室温浸泡提取得总浸膏，将总浸膏悬浮于水中，分别用石油醚和乙酸乙酯萃取，获得石油醚相和乙酸乙酯相萃取物。 采用常规的硅胶柱层析、制备薄层层析、凝胶Sephadex LH-20柱层析、反相硅胶柱层析、以及重结晶等手段，从黄槿和长梗肖槿的乙酸乙酯相中共分离得到43个化合物。利用各种现代波谱技术（IR、UV、MS、HR-MS、1D-NMR、2D-NMR等）确定了38个化合物的结构。其中，从黄槿的乙酸乙酯相中分离得到22个化合物，鉴定了其中19个化合物的结构，包括3个新的三萜类化合物(H1*-H3*)以及15个首次从该种中报道的化合物。从长梗肖槿的乙酸乙酯相中分离得到21个化合物，鉴定了其中19个化合物的结构，这些化合物皆为首次从该种中报道，其中1个为新的倍半萜类化合物T1*。本文为首次报道长梗肖槿的化学成分。 对分离得到的部分样品进行了抗菌活性测试，仅T1*表现微弱的抗金黄色葡萄球菌活性，抑菌圈直径为8mm（阳性对照氯霉素的抑菌圈直径为20mm），其余各样品在测试浓度下对测试菌株均未表现出活性。

山东沿海养殖栉孔扇贝大批死亡原因的初步研究

栉孔扇贝（Chlamysfarreri）是中国北方三种主要养殖扇贝中唯一的土著扇贝科种类,在中国主要分布在黄海北部和渤海海峡,过去一直是中国干贝的产出贝.该研究主要从养殖密度、病原、遗传三方面入手,研究和探讨造成养殖栉孔扇贝大批死亡的原因.2000年5月～9月,按高、中、低三种密度在山东胶南、蓬莱、烟台筏式挂养栉孔扇贝苗,分别在大规模死亡前、死亡高峰时和死亡后统计死亡率分别样本.对死亡期间的瞬时生长率研究发现,随着时间的推移,栉孔扇贝壳高增长率趋于减小,而扇贝全湿重的增长率却在T0-T1时间段呈现一个高峰,说明栉孔扇贝在大规模死亡前经历过一个块速增重的阶段.采用7条随机引物,对大连野生野体、韩国野生群体、中国日本杂交群体在胶南、蓬莱放养采样得到的养殖群体,总共5群体140个个体的全基因组DNA进行RAPD扩增,共扩增出37条谱带,其中30条具有多态性.

Genetic diversity and historical population structure of Schizopygopsis pylzovi (Teleostei : Cyprinidae) in the Qinghai-Tibetan Plateau

1. Complete sequences of 1140 base pair of the cytochrome b gene from 133 specimens were obtained from nine localities including the inflow drainage system, isolated lakes and outflow drainage system in Qinghai-Tibetan Plateau to assess genetic diversity and to infer population histories of the freshwater fish Schizopygopsis pylzovi.2. Nucleotide diversities (pi) were moderate (0.0024-0.0045) in populations from the outflow drainage system and Tuosuo Lake, but low (0.0018-0.0021) in populations from Qiadam Basin. It is probable that the low intra-population variability is related with the paleoenvironmental fluctuation in Qiadam Basin, suggesting that the populations from Qiadam Basin have experienced severe bottleneck events in history.3. Phylogenetic tree topologies indicate that the individuals from different populations did not form reciprocal monophyly, but the populations from the adjacent drainages cluster geographically. Most population pairwise F-ST tests were significant, with non-significant pairwise tests between Tuosu Lake and Tuosuo Lake in the north-west of the Qinghai-Tibetan Plateau. Analysis of molecular variance (AMOVA) indicates that the significant genetic variation was explained at the levels of catchments within and among, not among specific boundaries or inflow and outflow drainage systems.4. The nested clade phylogeographical analysis indicates that historical processes are very important in the observed geographical structuring of S. pylzovi, and the contemporary population structure and differentiation of S. pylzovi may be consistent with the historical tectonic events occurred in the course of uplifts of the Qinghai-Tibetan Plateau. Fluctuations of the ecogeographical environment and major hydrographic formation might have promoted contiguous range expansion of freshwater fish populations, whereas the geological barriers among drainages have resulted in the fragmentation of population and restricted the gene flow among populations.5. The significantly large negative F-s-value (-24.91, P < 0.01) of Fu's F-s-test and the unimodal mismatch distribution indicate that the species S. pylzovi underwent a sudden population expansion after the historical tectonic event of the Gonghe Movement.6. The results of this study indicate that each population from the Qinghai-Tibetan Plateau should be managed and conserved separately and that efforts should be directed towards preserving the genetic integrity of each group.

渤海湾盆地前第三系构造演化与煤成气成藏研究

The disequilibrium between supply and demand the east part of North China accelerated natural gas exploration in Bohai bay basin. Exploration practice showed that coal-derived gas is important resource. In searching of big to middle scaled coal derived gas field, and realize successive gas supply, the paper carried out integrated study on structural evolution of Pre-Tertiary and evaluation of reservoir forming condition of coal-derived gas. Study work of the paper was based on the following condition: available achievement in this field at present, good understanding of multiphase of tectonic movement. Study work was focused on geological evolution, source rock evaluation and dissection key factors controlling reservoir forming. Based on analysis of seismic data, drilling data, tectonic style of Pre-Tertiary was subdivided, with different tectonic style representing different tectonic process. By means of state of the art, such as analysis of balanced cross section, and erosion restoration, the paper reestablished tectonic history and analyzed basin property during different tectonic phase. Dynamic mechanism for tectonic movement and influence of tectonic evolution on tectonic style were discussed. Study made it clear that tectonic movement is intensive since Mesozoic including 2 phase of compressional movement (at the end of Indo-China movement, and Yanshan movement), 2 phase of extensional movement (middle Yanshan movement, and Himalayan movement), 2 phase of strike slip movement, as well as 2 phase of reversal movement (early Yanshan movement, and early Himalayan movement). As a result, three tectonic provinces with different remnant of strata and different tectonic style took shape. Based on afore mentioned study, the paper pointed out that evolution of Bohai bay basin experienced the following steps: basin of rift valley type (Pt2+3)-craton basin at passive continental margin (∈1－2)-craton basin at active continental margin (∈3- O)-convergent craton basin (C-T1+2)-intracontinental basin (J＋K). Superposition of basins in different stage was discussed. Aimed at tectonic feature of multiple phases, the paper put forward concept model of superposition of tectonic unit, and analyzed its significance on reservoir forming. On basis of the difference among 3 tectonic movements in Mesozoic and Cenozoic, superposition of tectonic unit was classified into the following 3 categories and 6 types: continuous subsidence type (I), subsidence in Mesozoic and uplift for erosion in Cenozoic (II1), repeated subsidence and uplift in Mesozoic and subsidence in Cenozoic (II2), repeated subsidence and uplift in Mesozoic and uplift for erosion in Cenozoic (II3), uplift for erosion in Mesozoic and subsidence in Cenozoic (II4), and continuous uplift (III). Take the organic facies analysis as link, the paper established relationship between sedimentary environment and organic facies, as well as organic facies and organic matter abundance. Combined information of sedimentary environment and logging data, the paper estimated distribution of organic matter abundance. Combined with simulation of secondary hydrocarbon generation, dynamic mechanism of hydrocarbon generation, and thermal history, the paper made static and dynamic evaluation of effective source rock, i.e. Taiyuan formation and Shanxi formation. It is also pointed out that superposition of tectonic unit of type II2, type II4, and type I were the most favorable hydrocarbon generation units. Based on dissection of typical primary coal-derived gas reservoir, including reservoir forming condition and reservoir forming process, the paper pointed out key factors controlling reservoir forming for Carboniferous and Permian System: a. remnant thickness and source rock property were precondition; b. secondary hydrocarbon generation during Himalayan period was key factor; c. tectonic evolution history controlling thermal evolution of source rock was main factor that determine reservoir forming; d. inherited positive structural unit was favorable accumulation direction; e. fault activity and regional caprock determined hydrocarbon accumulation horizon. In the end, the paper established reservoir forming model for different superposition of tectonic units, and pointed out promising exploration belts with 11 of the first class, 5 of the second class and 6 of the third class.

镓的成矿作用及其在峨眉山大火成岩省中的成矿效应

评述了分散元素镓的应用和成矿作用的研究现状并剖析了镓的成矿研究存在的主要问题。论证了铝土矿床中的镓主要赋存于其中的一水硬铝石且以GaO（OH）形式存在；以晶体化学理论分析，认为中高温热液条件形成的闪锌矿（主要包括铁闪锌矿、黑闪锌矿及富铜铅锌矿中的闪锌矿）是Ca的富集载体，Ca最可能以GaAs、GaxIn1-xAs和三元硫化物M^IGaS2（M^I=T1，Cu，Ag）分子的形式赋存，并可能于后期温度降低的条件下以单矿物（如硫镓铜矿）析出；镓在岩浆岩中的主要富集载体为长石类矿物、尖晶石型矿物以及具反尖晶石型结构的磁铁矿。对峨眉山大火成岩省中的重要矿床类型—攀枝花式超大型钒钛磁铁矿矿床中的代表性矿石进行镓含量分析并阐述了该类型矿床中Ca的成矿效应，初步评估了攀西地区钒钛磁铁矿工业储量中伴生的镓为34．8万t，远景资源量为43．5万t，认为该区超大型钒钛磁铁矿矿床亦属超大型镓矿床，具潜在的重要经济价值。呼吁加强对我国磁铁矿矿床中镓的成矿效应及综合利用的系统研究。

滇黔桂地区铊富集的矿化剂和沉淀富集剂及成矿模式

T1虽然是一种分散元素，但在一定条件下也是可以富集的，甚至形成独立矿体。笔者在分析滇黔桂地区富铊矿床的地球化学特征后，认为T1在低温阶段富信，并提出T1的富集与沉积盆地局部高地球化学背景有关；促使T1富集万丈和的主要条件是矿化剂和沉淀富集剂，卤素和有机质是主要的成矿化剂，富硫流体和热液改造的有机质是主要的沉淀富集剂，在此基础上进一步探讨铊的二期三阶段成矿模式。

表生条件下铊矿物的氧化溶解动力学及其反应性迁移实验研究

贵州省兴仁县滥木厂铭矿床是世界上唯一的铭的独立矿床。多年来，由于对蛇矿产资源的开发，大量未及时提取和利用的含佗矿石堆积于地表，经过风化淋滤作用，进入当地的水源和土壤，并通过食物链进入人体。20世纪60-70年代，滥木厂地区有近1000名村民患有不同程度的铂中毒，轻者脱发、视力减退，重者失明、丧失劳动力，至今在该地区仍可见到铭中毒患者。该区成为世界上唯一爆发过大规模馆中毒的病发区。馆又是人体的非必需元素，体内任何含量的馆都会对人体造成危害。饮用水的安全标准中，铭的含量不得超过1μg／L。因此对表生条件下，含铂矿物的氧化溶解动力学以及反应性迁移的实验研究具有重要的现实意义。通过对滥木厂铭矿床中的主要含铭矿物（红铭矿）在酸性矿水条件下的氧化溶解过程、光照旧光照射和汞弧灯照射）对铭价态改变的影响，以及酸性矿水条件下铁对蛇吸附的实验研究，得到如下几点认识：1．红铭矿的氧化溶解动力学实验表明：红铂矿的氧化溶解速率受到温度、氧化剂中阴离子种类及氧化剂浓度的影响。随着温度的升高，红蛇矿的氧化速率增高；Cl-离子的存在更有助于红锭矿的氧化溶解，表现为氧化溶解速率的增高；随着氧化剂浓度的升高，红铭矿的氧化速率逐渐降低，这主要是由于高铁浓度下，红佗矿表面形成了一层厚约2nm的铁硫化合物的膜，减缓了红铭矿进一步溶解。红铭矿表面形态和成分的电镜分析表明，红铭矿表面具有较多的活性点，因此含铭矿石在初露地表时对环境的污染比较强烈，经过风化淋滤作用后，红铭矿表面的活性点减少，加之硫铁化合物膜的形成，阻止了其对环境的进一步污染。但这并不排除一旦环境介质改变，红铭矿表面氧化形成的膜被破坏，红铭矿的新鲜表面暴露出来，活性点增多，溶解性加强，继续对周围环境造成强烈的污染。从红蛇矿24小时溶解的总馆量来看，酸性矿水条件下红佗矿的氧化溶解是贵州省兴仁县滥木厂地区佗污染的一个重要来源。2．铭的光致氧化实验结果表明：无论日光还是汞弧灯照射，水溶液中的T1（I）均可被氧化成T1（III）。州值越低、光照强度越大，铭的光氧化速率越快，UVB区的紫外光对铭的光氧化起着主要作用，微生物作用在本实验条件下，相对于光氧化作用并不明显。3．铁对铭的吸附实验表明：铁的水合氧化物对水溶液中铭的吸附除受溶液的pH值和吸附剂的阴离子种类的影响外，主要与佗的价态有直接关系。铁的水合氧化物对Tl（I）具有一定的吸附能力，阴离子种类对T1（I）吸附的作用稍有差别，C1-离子存在时，铁对Tl（I）的吸附更强一些吸附率达到50％左右，而S叮一离子存在条件下，铁对Tl（I）的吸附率小于20％。碱性（pH＝10左右）条件下，铁对T1（I）的吸附较中胜条件更明显一些。T1（III）由于自身的水解作用很强，在不同pH值和不同阴离子存在条件下，与Fe（III）均可发生共沉淀作用而被完全从水溶液中脱除。利用光照将Tl（I）氧化成Tl（III），再利用T1（III）易被沉淀或共沉淀吸附的特性，将Tl以Tl（OH）3，的形式吸附固定下来，降低了铭的活动性，进而可以减少铭对环境的影响，为锭污染的环境治理提供了重要的理论依据。

Morfometria da cabeça espermática em touros Nelore submetidos a deficiência de zinco na dieta.

Touros jovens da raça Nelore (n=6) foram mantidos em pasto formado de Brachiaria brizantha desde a desmama em dietas com diferentes níveis de zinco. Foram formados aleatoriamente dois grupos que receberam diariamente, durante dois anos, diferentes concentrações de zinco no sal mineral: T1 (n=4), os animais não receberam suplemento com zinco e T2 (n=2), 60 mg/kg/dia de Zn inorgânico suplementar. A concentração de Zn na pastagem variou de 17,8 (águas) a 12,8 mg/kg (seca), respectivamente. A partir dos 14 meses de idade, os animais foram submetidos quinzenalmente a exame de sêmen e colheita de sangue. A morfologia espermática foi estimada, incluindo a mensuração da cabeça espermática a partir de esfregaços coradas pelo método de Fuelgen, em imagens captadas digitalmente e processadas pelo software Kontron Eletronik Imaging System, KS 400-2.0. A concentração de zinco no plasma foi dosada por spectrofotometria de absorção atômica. Os resultados mostraram que os touros do T1 tiveram qualidade seminal inferior (P<0,05) em relação ao T2. Observou-se variação das características seminais em função da data da colheita, evidenciando efeito estacional sobre a qualidade do sêmen. Os defeitos mais encontrados foram de peça intermediária e cauda. A concentração de Zinco (Zn) na circulação sangüínea foi maior (P<0,01) no T1 em comparação ao T2 (0,72 ±0,01 x 0,66 ±0,01, respectivamente). A área da cabeça espermática de espermatozóides morfologicamente normais e com defeitos de cabeça, peça intermediária e cauda foi maior (P<0,01) para os touros do T1 em relação aos do T2. Ademais, espermatozóides com fragmentação nuclear apresentaram forma mais alongada quando comparados àqueles sem alterações morfológicas. As correlações encontradas sugerem a importância do Zn na qualidade seminal, especialmente pelos efeitos deletérios que sua deficiência (subclínica) causa na morfologia espermática.

Robust, High-Speed Network Design for Large-Scale Multiprocessing

As multiprocessor system size scales upward, two important aspects of multiprocessor systems will generally get worse rather than better: (1) interprocessor communication latency will increase and (2) the probability that some component in the system will fail will increase. These problems can prevent us from realizing the potential benefits of large-scale multiprocessing. In this report we consider the problem of designing networks which simultaneously minimize communication latency while maximizing fault tolerance. Using a synergy of techniques including connection topologies, routing protocols, signalling techniques, and packaging technologies we assemble integrated, system-level solutions to this network design problem.

A Circuit Grammar For Operational Amplifier Design

Electrical circuit designers seldom create really new topologies or use old ones in a novel way. Most designs are known combinations of common configurations tailored for the particular problem at hand. In this thesis I show that much of the behavior of a designer engaged in such ordinary design can be modelled by a clearly defined computational mechanism executing a set of stylized rules. Each of my rules embodies a particular piece of the designer's knowledge. A circuit is represented as a hierarchy of abstract objects, each of which is composed of other objects. The leaves of this tree represent the physical devices from which physical circuits are fabricated. By analogy with context-free languages, a class of circuits is generated by a phrase-structure grammar of which each rule describes how one type of abstract object can be expanded into a combination of more concrete parts. Circuits are designed by first postulating an abstract object which meets the particular design requirements. This object is then expanded into a concrete circuit by successive refinement using rules of my grammar. There are in general many rules which can be used to expand a given abstract component. Analysis must be done at each level of the expansion to constrain the search to a reasonable set. Thus the rule of my circuit grammar provide constraints which allow the approximate qualitative analysis of partially instantiated circuits. Later, more careful analysis in terms of more concrete components may lead to the rejection of a line of expansion which at first looked promising. I provide special failure rules to direct the repair in this case.