以树木年轮宽度资料重建祁连山中部地区过去248年来的降水量

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南海北部湾23/25太阳区块海底工程地质调查与评价

<正> 本项成果,是承包美国太阳东方勘探公司任务而完成的。在系统分析总结了南海西部石油公司“南海—503工程地质取芯船”在南海北部湾23/25太阳区块所进行的测深、侧扫声纳、地震声学剖面测量,及4口孔深40米的工程地质浅钻土柱等材料的基础上,详细阐述了

SiC_p/6151Al复合材料的微结构效应

利用分离式Hopkinson压杆和MTS通用材料试验机研究了SiC_p/6151Al颗粒增强复合材料在不同应变率下的变形行为和增强颗粒的尺寸对复合材料微结构及变形行为的影响。结果表明，对于在不同应变率下的SiC_p/6151Al复合材料，增强颗粒尺寸大小的流动应力高于增强颗粒尺寸的流动应力。根据位错强化理论中的Hall-Petch关系对这个结果进行了解释。首次在实验上观测到增强颗粒对复合材料微损伤-微带形成的影响，并根据微带（microband）形成的双位错墙理论（double dislocation walls）, 分析了增强颗粒对复合材料微带损伤及力学性能影响的微结构效应。

碳纳米管-Mg_(65)Cu_(25)Gd_(10)非晶复合材料玻璃转变的动力学性质

制备了Mg65Cu25Gd10大块非晶合金及其碳纳米管(CNTs)复合材料,对两种材料进行了不同扫描速率下的差热扫描量热分析,研究了加入CNTs对材料玻璃转变和晶化动力学效应的影响。结果表明:加入CNTs后,复合材料的玻璃转变和晶化行为仍然具有动力学效应,但加入的CNTs减小了材料晶化行为对升温速率的依赖程度;同时,加入CNTs加大了材料发生玻璃转变时需要克服的能量势垒,增大了峰值温度时的晶化反应速率常数,从而降低了材料的玻璃形成能力(GFA);对CNTs降低GFA的原因也进行了探讨。

纳米压痕和划痕法测定氧化硅薄膜材料的力学特性

为了研究不同制备工艺对材料力学性能的影响 ,选择了热氧化、LPCVD和PECVD三种典型工艺 ,在硅片上制备 1μm氧化硅薄膜。通过纳米压痕和划痕检测可知 ,热氧化工艺制备的SiO2薄膜的硬度和模量最大 ,LPCVD制备的样品界面结合强度高于PECVD。纳米压痕和划痕技术为此提供了丰富的近表面弹塑性变形和断裂等的信息 ,是评价微米薄膜力学性能的有效手段

超声速化学反应流动中燃料预喷研究述评

研制基于超声速燃烧的高效吸气式推进装置(运行Mach数在3.5以上)需要寻求改善混合效率的有效机制,这对于采用常规碳氢燃料(特别是可以增加密度的液体燃料)的装置尤为重要.延长混合时间的一种途径是在飞行器燃料室的上游喷入部分燃料.壁面喷射一直是超声速气动力学最具挑战性的课题,这里包括使比冲损失最小、改善燃料-空气的混合、减少入口段/燃烧室的相互作用以及增进火焰稳定性等.综述了超声速入口段或燃烧室的隔离器中液体燃料(个别情况下为气体燃料)喷射的研究进展.在这些研究中,燃料都是从后掠型细支架尾迹中的壁面处喷射出来的,动压比很低(qjet/qair=0.6～1.5).它们涉及入口段和燃烧室的隔离器中单个支架/喷射器的几何结构及其组合方式、各种各样的喷射条件、不同的引射剂,并且评估了这些因素对于燃料羽流喷散、比冲损失以及混合效率的影响.述评引用了46篇参考文献.

Influence of ZrO2 in HfO2 on reflectance of HfO2/SiO2 multilayer at 248 nm prepared by electron-beam evaporation

Influence of ZrO2 in HfO2 on the reflectance of HfO2/SiO2 multilayer at 248 nm was investigated. Two kinds of HfO2 with different ZrO2 content were chosen as high refractive index material and the same kind of SiO2 as low refractive index material to prepare the mirrors by electron-beam evaporation. The impurities in two kinds of HfO2 starting coating materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum (GDMS) technology and secondary ion mass spectrometry (SIMS) equipment, respectively. It showed that between the two kinds of HfO2, either the bulk materials or their corresponding films, the difference of ZrO2 was much larger than that of the other impurities such as Ti and Fe. It is the Zr element that affects the property of thin films. Both in theoretical and in experimental, the mirror prepared with the HfO2 starting material containing more Zr content has a lower reflectance. Because the extinction coefficient of zirconia is relatively high in UV region, it can be treated as one kind of absorbing defects to influence the optical property of the mirrors. (C) 2008 Elsevier B.V. All rights reserved.

Conserved chromosome segments in Hylobates hoolock revealed by human and H-leucogenys paint probes

A complete comparative chromosome map of the white-browed gibbon (Hylobates hoolock, 2n = 38), white-cheeked gibbon (Hylobates leucogenys, 2n = 52), and human has been established by hybridising H. leucogenys chromosome-specific paints and human 24-colour paints onto H. hoolock metaphase chromosomes. In the 18 H. hoolock autosomes, we identified 62 conserved segments that showed DNA homology to regions of the 25 H. leucogenys autosomes, Numerous interchromosomal rearrangements differentiate the karyotypes of H. leucogenys and H. hoolock. Only H. hoolock chromosome 10 showed homology to one entire autosome of H. leucogenys. The hybridisation of human 24-colour paints not only confirmed most of the chromosome correspondences between human and H. hoolock established previously but also helped to correct five erroneous assignments and revealed three new segments. Our results demonstrate that the karyotypes of the extant gibbons have arisen mainly through extensive translocation events and that the karyotype of H. hoolock more closely resembles the ancestral karyotype of Hylobates, rather than the karyotype of H. leucogenys. Copyright (C) 2001 S. Karger AG, Basel.

树qu红核的细胞构筑和红核脊髓束的起源

用Nissl法染色和HRP注入树qu脊髓的不同节段,结果表明,树qu红核和上丘高度向吻侧延伸至乳头体内侧核尾端,细胞柱呈梭状,长约3.7mm,最大处直径2mm。它由大(60-100#mu#m)、中(30-50#mu#m)和小型(10-25#mu#m)细胞构成。红核吻段大细胞较多,占60.7%,中尾段中小型细胞多,占71.7%,, 中、小细胞散在分布于大细胞之间。树qu的红核-脊髓束主要由对侧红核大、中和小型细胞发出的纤维组成;红核吻段背侧部,中尾段的腹部、腹中部和腹中背部细胞发出的纤维交叉投射到颈吻段;红核吻、中、尾段的腹部、腹中部和腹中背部细胞发出的纤维还投射到对侧颈尾段;红核中尾段的腹部、腹中部、腹中背部细胞也有纤维交叉投射到腰段;只有红核吻段和尾段少量细胞发出的纤维投射到同侧颈段。

斜带石斑鱼生长激素/催乳素家族基因cDNAs的分子克隆及其进化意义

从斜带石斑鱼垂体提取总RNA ,再取其 5 0ng合成SMARTcDNA。从所构建的垂体SMARTcDNA质粒文库中筛选到生长激素 /催乳素基因家族的 2个成员的全长cDNA片段 :生长激素 (GH )基因全长为 938bp ,编码 2 0 4个氨基酸 ;催乳素基因 (PRL)全长为 14 2 9bp ,编码 2 12个氨基酸。采用计算机软件Mega 2和CLUSTALW1 6 4b对 9种鱼的生长激素 /催乳素基因家族的 3个成员 (GH、PRL和生长催乳素SL)的氨基酸序列进行系统分析 ,构建NJ分支

Distribution of 25 semi-volatile organic compounds of two urban lakes in Wuhan, China

In this study, the levels of 25 semi-volatile organic compounds (SVOCs) were measured in samples of water, suspended particulate matter (SPM) and sediment from two urban lakes in Wuhan, China. The total concentrations of 25 SVOCs varied from 529.4 to 2168.9 ng/L, 120.7 to 22543.7 ng/g dry weight and 1577.3 to 61579.6 ng/g dry wt. in water, SPM and sediment, respectively. The concentration of SVOCs in SPM was 9-10 times higher than that in water, and the concentration of SVOCs in sediment 1.5-2 times higher than that in SPM. The level of total SVOC25 in the samples from Moshuihu Lake was higher than that in Yuehu Lake. Among the 25 SVOCs, phthalate compounds were on the highest level in all observed samples ranging between 441.9-1831.2 ng/L, 116.3-17566.8 ng/g, dry wt. and 6432.8-48177.6 ng/g dry wt. in water, SPM and sediment, respectively. Bis(2-ethylhexyl)phthalate, the predominant component of the analyzed pollutants, was in the range from 246.7 to 537.5 ng/l, 51.2 to 15540.0 ng/g dry wt. and 468.2 to 45010.3 ng/g dry wt. in water, SPM and sediment, respectively. The content of PAHs, dinitrotoluene and isophoton in sediment was higher than that in water and SPM at most of the locations. The possible sources of the pollutants and their inter-relation with human activities were discussed.