Laboratory study on cracks in saturated sands

It has been reported([1]) that when a loosely packed column of saturated sand in a vertical cylindrical container is shock loaded axially by dropping to the floor, large horizontal cracks initiate, grow and eventually fade away in the sand as it settles under gravity. This paper shows that a similar phenomenon can also be observed when shock loading is replaced by forcing water to percolate upward through the sand column. It is believed that our result sheds further light on the physics of formation of these cracks.

波动方程反演问题的一种新的逼近方法

本文给出了一种求解波动方程反演问题的“多目标函数法”.这种方法简单、有效,并具有明确的物理意义.对于三维问题的程序化它有很强的优越性.

Internal resonance of an L-shaped beam with a limit stop .2. Forced vibration

A limit stop is placed at the elbow of an L-shaped beam whose linear natural frequencies are nearly commensurable. As a result of this hardening device the non-linear system exhibits multiple internal resonances, which involve various degree of coupling between the first five modes of the beam in free vibration. A point load is so placed as to excite several modes and the resulting forced vibration is examined. In the undamped case, three in-phase and two out-of-phase solution branches have been found. The resonance curve is extremely complicated, with multiple branches and interactions between the first four modes. The amplitudes of the higher harmonics are highly influenced by damping, the presence of which can effectively attenuate internal resonances. Consequently parts of the resonance curve may be eliminated, with the resulting response comprising different distinctive branches. (C) 1996 Academic Press Limited

双折射光纤中色散管理孤子研究

本文研究色散管理孤子在双折射光纤中的传输特性。应用变分法分析并给出了双折射光纤中色散管理孤子参量演化的常微分方程，数值分析双折射对孤子参量的影响，分析发现在双折射光纤中色散管理孤子的宽度和啁啾不再是严格周期性变化，在色散管理的同时进行周期性偏振补偿可以消除走离效应，可以产生管理孤子。

532 nm激光泵浦硝酸钡晶体产生外腔拉曼激光

由于硝酸钡晶体具有很强的对称振动（频率1047 cm^-1）和较高的拉曼增益,可以用来产生受激拉曼激光.采用单端泵浦的外置拉曼振荡腔与双棱镜分光装置进行了硝酸钡晶体拉曼激光实验,泵浦源为倍频Nd： YAG的532 nm激光,硝酸钡晶体通过水溶液降温法生长,尺寸为10 mm×10 mm×48 mm,采用特殊镀膜的腔镜对各阶斯托克斯光进行优化选择.在泵浦源达到65 mJ时,获得21 mJ一阶斯托克斯光,输出波长为563 nm,以及16 mJ的二阶斯托克斯光,输出波长为599 nm,受激拉曼散射SRS最大的整体

北京市土壤--植物系统重金属硫的分布迁移相互间关系和主成份分析

本文选择了北京市香山北京植物园、北京动物园、长安街和北京化工厂4个功能区和国槐（Sophora japonica (L) Beauv)、毛白杨 (populus tomentosa Carr)、丁香(Syringa Oblata)、野牛草(Buohloe dactyloides (Nutt) Engelm)4种植物;采集植物样品105个、土壤样品40个;测定了各样品的镍(Ni)、锌(Zn)、铜(Cu)、镉(Cd)、铅(Pb)、铬 (Cr)、硫(S)7种元素含量;通过对样品元素含量的直观分析、回归分析、主成份分析(PCA)，得出以下结论：各样品各元素含量的最高值或异常值多出现在化工厂内，其次是长安街、动物园、北京植物园无;各功能区各样品各元素含量大小顺序多是：化工厂><长安街>动物园><北京植物园：表明化工厂内土壤、植物受污染的程度较重，其次是长安街，动物园稍轻，北京植物园则较洁净。土壤中7种元素分布特征是：S > Zn > Pb > Cr > Cu > Ni > Cd;植物中7种元素分布特征是：S > Zn >< Cu > Pb > Cr >< Ni >< Cd。7种植物样品对S、Zn、Cu、 Cd具较大的富集系数;对Ni、Pb、Cr具较小的富集系数;说明前者比后者在土壤—植系统中较易迁移。7种植物样品对S均具积累效应;毛白杨叶对zn，毛白杨叶、枝、国槐皮对Cd，野牛草对Cu也都具积累效应。国槐各器官元素含量分配是：皮含量>叶含量>枝含量;毛白杨各器官元素含量分配是：叶含量>枝含量;表明植物各器官中，枝元素含量较低。对元素含量回归分析，发现植物各器官元素含量间具显著性正相关系;植物中元素含量与土壤中元素含量绝大多数呈正相关。前者说明植物各器官生长发育的正相关性;后者说明土壤条件与植物生长发育的正相关性。对元素含量的主成份分析和样品排序，揭示出采自同一功能区的样品大都可形成一集团，但尚存在交叉、重叠和过渡的样品;化工厂集团多处在排序图Z1轴左边，长安街集团多处在Z2轴上方，北京植物园集团多处在Z1轴右边或Z2轴下方。可明确得出，化工厂土壤、植物污染较重（元素含量较高），其次是长安街;动物园污染稍轻，北京植物园较洁净的结论。还可知，化工厂、长安街某些样点污染较轻;而北京植物园、动物园某些样点污染较重。

贻贝凝集素抗-HIV活性研究

分离提取海洋无脊椎动物贻贝(Crenomytilus grayanus)凝集素,考察其抗HIV活性。采用半乳糖-Sepharose 6B亲和层析和Sephacryl S-200层析分离提取贻贝凝集素(Crenomytilus grayanus lectin,CGL),以光镜检查合胞体抑制试验,以ELSA测定HIVp24抗原表达水平。从海洋无脊椎动物贻贝中分离出的凝集素(CGL),为N-乙酰半乳糖胺/半乳糖(GalNAc/Gal)特异性的凝集素。CGL在27.88mg.L-1浓度时,对HIV诱导细胞病变的抑制达50%;在45.70mg.L-1时,对HIV-1复制的抑制达50%;同时在35.12mg.L-1浓度时,对HIV感染细胞融合的阻断达50%。

Seasonal variations in the activity budget of Nomascus concolor jingdongensis at Mt. Wuliang, Central Yunnan, China: Effects of diet and temperature

We studied seasonal variation in the activity budget of a habituated group of Nomascus concolor jingdongensis at Mt. Wuliang, Central Yunnan, China from March 2005 to April 2006 via scan sampling at 5-min intervals. The study site is near the northern extreme of the distribution of hylobatids, at high altitude with extreme seasonality of temperature and rainfall. During the day, feeding manifested a bimodal pattern of high activity levels in mid-morning and mid-afternoon, whereas resting reached a peak at midday, with proportionally less time used for traveling. Annually, the group spent an average of 40.0% of the time resting, 35.1% feeding, 19.9% traveling, 2.6% singing, 1.2% playing, and 1.3% in other activities. The proportion of time allocated to activities showed significant monthly variations and was influenced by the diet and temperature. Gibbons increased traveling and playing time and decreased feeding time when they ate more fruit, and they decreased traveling, singing, and playing time and increased feeding time when they ate more leaves. Moreover, when the temperature was low, the gibbons decreased time traveling and increased time resting. In summary, black-crested gibbons employed high-effort activities when they ate more fruit and energy-conservation patterns when they ate more leaves and in low temperature. Behavioral data from the site are particularly useful in understanding gibbon behavioral adaptations to different sets of ecological conditions.

Molecular cloning and stress-induced expression of paralichthys olivaceus heme-regulated initiation factor 2 alpha kinase

The heme-regulated initiation factor 2 alpha kinase (HRI) is acknowledged to play an important role in translational shutoff in reticulocytes in response to various cellular stresses. In this study, we report its homologous cDNA cloning and characterization from cultured flounder embryonic cells (FEC) after treatment with UV-inactivated grass carp haemorrhagic virus (GCHV). The full-length cDNA of Paralichthys olivaceus HRI homologue (PoHRI) has 2391 bp and encodes a protein of 651 amino acids. The putative PoHRI protein exhibits high identity with all members of eIF2 alpha kinase family. It contains 12 catalytic subdomains located within the C-terminus of all Ser/Thr protein kinases, a unique kinase insertion of 136 amino acids between subdomains IV and V, and a relatively conserved N-terminal domain (NTD). Upon heat shock, virus infection or Poly PC treatment, PoHRI mRNA and protein are significantly upregulated in FEC cells but show different expression patterns in response to different stresses. In healthy flounders, PoHRI displays a wide tissue distribution at both the mRNA and protein levels. These results indicate that PoHRI is a ubiquitous eIF2a kinase and might play an important role in translational control over nonheme producing FEC cells under different stresses. (c) 2006 Elsevier Ltd. All rights reserved.