椭圆背角无齿蚌对水中重金属的积累作用及其氨基酸含量的变化

饲养在滇池水中的椭圆背角无齿蚌氨基酸含量只有饲养在松华坝水库水中蚌的氨基酸含量一半,质量分数分别是680 57mg/hg和1477 14mg/hg。检测表明椭圆背角无齿蚌对砷、铅、锌、铜、铁元素有一定的富集能力,说明由于滇池污染,椭圆背角无齿蚌在滇池中虽然可以生存,但这一物种资源的利用价值受到严重影响。

富营养湖泊滇池水华蓝藻的机械清除

富营养湖泊暴发蓝藻水华时可集聚浓度达n× 10 8— 9cell/L ,利用重力振动、旋振和离心等方法收集富藻水 ,逐次浓缩、脱水后得藻泥 ;根据需要可对藻泥进行干燥 ,得到干藻粉。 2 0 0 1年 4月至 2 0 0 2年 11月在云南滇池以上述方式清除蓝藻水华 35 1d ,共处理富藻水 4 2 6 4 8m3 ,折合清除水华蓝藻干重为 4 6 0 .83t。按所清除的蓝藻干粉的总氮、总磷、总钾、粗有机质及重金属的平均含量计算 ,相当于从试验区水体中去除了氮 (N) 37.33t、磷 (P) 2 .

稚幼鱼的营养与饲料研究进展

中国科学院知识创新方向性项目 (ZKCX 2 11) ; 中国科学院前沿性创新项目资助

藏北色林错流域的水文特征

本文报道了 1997年和 1998年夏季对藏北色林错等水体水文特征的考察情况 .结果表明 ,色林错是一个大型深水湖泊 ,表层水温在下午 4 :30左右达到最高 ,清晨 7:30左右时最低 .浅水区域表层湖水在 6月份的极端最高水温为 2 1.2℃ ,极端最低水温为 11.0℃ ,而日平均水温变幅仅 5.6℃ ,其幅度大于在同一时段湖区内不同区域之间表层水温的变化 .色林错湖水的 pH值较高 ,为 9.19- 9.66;表层水的 pH昼夜变化较小 ,仅 0 .15,最高值出现在凌晨 ,同时水体不同区域及深度

鲫鱼囊胚细胞干扰素的诱导及部分特性

用紫外线灭活的草鱼呼肠孤病毒 (GCRV)诱导鲫鱼囊胚细胞 (CAB)能产生一种高滴度的抗病毒物质。这种物质在 5 6℃及 pH 2～ 11稳定 ;对胰蛋白酶敏感 ;抗病毒活性受被保护细胞的密度、培养温度及保护时间的影响 ;不能被GCRV的特异性抗体中和 ;无直接杀病毒作用 ;抗病毒机制依赖于细胞内RNA和蛋白质的合成 ;在多种鱼类培养细胞中具有抑制病毒作用。这些特性与哺乳类α/ β干扰素一致 ,是一种鲫鱼干扰素

稚鳖的性别分化及组织学研究

解剖出生１５～４５ｄ的稚鳖，所有个体的性腺呈细线状，肉眼分辨不出雌雄。组织学研究发现，雌雄个体的性别都已明显分化。雄性精巢的外壁由两层膜构成，其内部由许多隔膜分隔成许多精细管，精细管里充满原始的精母细胞；雌性卵巢有卵巢腔和输卵管，由结缔组织、毛细血管和生殖上皮形成卵巢膜和基质，并把卵巢分隔成一个个小室，原始的卵泡就在这些小室中生长、发育。

ADSORBABILITY AND SEDIMENTATION EFFECT OF SUBMERGED MACROPHYTES ON SUSPENDED SOLIDS

To select better plant species for adsorption and deposition of suspended solids in water, effectively, eight species of submerged macrophytes, which are popular in the middle or downstream area of Yangtze River, were studied. The effects of their adsorbability and sedimentation on suspended solids were monitored in the microcosm systems with natural lake's sediment and water. Within one week's regular disturbance, according to their adsorbability of the macrophytes on suspended solids, the macrophytes were divided into two groups. Elodea nuttallii, Potamogeton crispus, Hydrilla verticillata, Myriophyllum spicatum, Potamogeton malaianus and Najas graminea were the macrophytes with stronger adsorbability. Vallisneria natans and Ceratoplyllum demersum were the macrophytes with weaker adsorbability. The average adsorbabilities of the two groups were 28.0 and 14.5 mg g(-1) FW-1, respectively. According to the sedimentation rate, the macrophytes were divided into three groups. P. crispus and H. verticillata were in the highest group. V.natans was in higher group. E nuttallii, M. spicatum, N. graminea, C demersum and P. malaianus were in the lowest group. The average sedimentation rates of the three groups were 3.42, 2.11 and 0.69 mg l(-1) d(-1). respectively. Therefore, P. crispus and H. verticillata were excellent species. C demersum was a poor species to improve transparency of water body.

Seasonal dynamics and distribution of the digenean Phyllodistomum pawlovskii (Trematoda : Gorgoderidae) in the bullhead catfish, Pseudobagrus fulvidraco, in a lake of China

Seasonal population dynamics of the digenean Phyllodistomum pawlovskii in the urinary bladder of the bullhead catfish, Pseudobagrus fulvidraco, were investigated in Liangzi Lake in the flood plain of the Yangtze River in China from February 2001 to July 2002. The overall prevalence of the parasite was high, 41.5% (n = 1,476), while the mean abundance was relatively low, 1.24 +/- 2.11. The parasite exhibited evident seasonality in changes of prevalence and abundance. In brief, prevalence and abundance were very low in midwinter (January), but increased and remained relatively high in other seasons and months. The distribution pattern of this parasite in the fish was overdispersed, with a variance to mean ratio > 1, but its frequency distribution could not be described by the negative binomial model. There were positive correlations between the number of the parasites per fish and the age and length of the fish; a peaked age-parasite abundance curve was not detected in the parasite-host association. It is suggested that the parasite P. pawlovskii has little effect on the population structure of the bullhead catfish.

Enhanced resistance to Aeromonas hydrophila infection and enhanced phagocytic activities in human lactoferrin-transgenic grass carp (Ctenopharyngodon idellus)

Human lactoferrin (hLF) is an iron-binding protein with antimicrobial and immunomodulatory activities. hLF cDNA was transferred into grass carp via electroporated sperm. The production of transgenic fish was as high as 55% tinder the best parameters. 2(11) pulses and 20-min incubation. The expression of the transgene was demonstrated by the detection of hLF mRNA by RT-PCR. We also investigated the response of G(0) transgenic grass carp to Aeromonas hydrophila infection. Serum lysozyme activities (P>0.05) and phagocytic activities of kidney cells (P<0.05) were measured in transgenic individuals. The transgenic fish not only cleared A. hydrophila significantly faster than the control carp (P<0.05), but also showed enhanced phagocytic activities. The result shows that hLF has immunomodulatory activities in hLF-transgenic grass carp. The transgenic grass carp exhibited enhanced immunity to A. hydrophila infection. These results reveal that the mechanisms of disease resistance are different between hLF-transgenic plants and hLF-transgenic grass carp. (C) 2004 Elsevier B.V. All rights reserved.

Electronic structure of a hydrogenic acceptor impurity in semiconductor nano-structures

The electronic structure and binding energy of a hydrogenic acceptor impurity in 2, 1, and 0-dimensional semiconductor nano-structures (i.e. quantum well (QW), quantum well wire (QWW), and quantum dot (QD)) are studied in the framework of effective-mass envelope-function theory. The results show that (1) the energy levels monotonically decrease as the quantum confinement sizes increase; (2) the impurity energy levels decrease more slowly for QWWs and QDs as their sizes increase than for QWs; (3) the changes of the acceptor binding energies are very complex as the quantum confinement size increases; (4) the binding energies monotonically decrease as the acceptor moves away from the nano-structures' center; (5) as the symmetry decreases, the degeneracy is lifted, and the first binding energy level in the QD splits into two branches. Our calculated results are useful for the application of semiconductor nano-structures in electronic and photoelectric devices.

Side radical influence on the nonlinear optical properties and thermal stability of poled polymer films

Films of polyetherketone doped with the chromophores Disperse Red 1 (DR1) and Disperse Red 13 (DR13) were prepared by spin-coating method. By the in situ Second-harmonic Generation (SHG) signal intensity measurement, the optimal poling temperatures were obtained. For the investigated polyetherketone polymer doped with DR1 (DR1/PEK-c) and polyetherketone polymer doped with DR13 (DR13/PEK-c) films, the optimal poling temperatures were 150degreesC and 140degreesC, respectively. Under the optimal poling conditions, the high second-order nonlinear optical coefficient chi(33)((2)) = 11.02 pm/V has been obtained for the DR1/PEK-c; and for DR13/PEK-c at the same conditions the coefficient is 17.9 pm/V. The SHG signal intensity DR1/PEK-c could maintain more than 80% of its initial value when the temperature was under 100degreesC, and the SHG signal intensity of the DR13/PEK-c could maintain more than 80% of its initial value when the temperature was under 135degreesC. (C) 2002 Kluwer Academic Publishers.

Investigation of the polyetherketone guest-host DR1/PEK-c polymer films by real-time monitoring of the second-harmonic generation

The real-time monitoring of the second-harmonic generation (SHG) was used to optimize the poling condition and to study the nonlinear optical (NLO) properties of the polyetherketone (PEK-c) guest-host polymer films. The high second-order NLO coefficient chi(33)((2)) = 11.02 pm/v measured at 1.064 mu m was achieved when the weight percent of DR1 guest in the polymer system is 20%. The NLO activity of the poled DR1/PEK-c polymer film can maintain more than 80% of its initial value when temperature is under 100 degrees C, and the normalized second-order NLO coefficient can maintain more than 85% after 2400 s at 80 degrees C. (C) 2000 Elsevier Science Ltd. All rights reserved.

半导体光电子技术

本书是“高新技术科普丛书”之一。作为信息领域的核心技术，半导体光电子技术在光通信、光盘存储、光纤传感、激光加工以及医疗、军事等方面有着重要的应用，它的发展将直接影响世界经济的进展和人类生活水平的提高。全书共11章，第1章介绍半导体光电子技术的由来和发展趋势；第2、3章重点介绍半导体光电子材料和器件工作原理；第4章到第9章介绍半导体激光器、探测器、光波导器件、光电子集成的结构和特性以及外延生长、微细加工等制造技术，同时介绍了CCD、太阳能电池等器件；最后两章介绍半导体光电子技术的应用。

Q的线性密码分析

对NESSIE公布的17个分组密码之一的Q进行了线性密码分析，攻击所需的数据复杂不大于2^118(相应的成功率为0．785），空间复杂度不大于2^33+2^19+2^18+2^12+2^11+2^10。此结果显示Q对线性密码分析是不免疫的。

用分子动力学模拟水合物储氢

用分子动力学（MD）模拟方法系统研究了结构Ⅰ型（SⅠ）和结构H型（SH）氢气水合物中氢气的占据情况并确定了氢气水合物的稳定结构：SⅠ水合物氢气分子数小胞中为2，大胞中为3；SH水合物氢气分子数小胞中为2，中胞中为2，大胞中为11．分析了稳定情况下水合物各胞腔内氢气分子之间的径向分布函数（RDF），得出了氢气分子在各胞腔内的稳定位置．由稳定位置得到了稳定结构下氢气水合物的储氢质量分数：SⅠ为5．085％，SH为6．467％．与实验对比得出结论：SH水合物稳定结构下的储氢能力最强．