草鱼出血病病原的研究

草鱼出血病是草鱼种的一种严重疾病,通常在水温25-30℃时发病,其症状表现为全身性组织器官充血。其病原悬液能通过赛氏滤器(Seitz,EKS石棉滤板),能在草鱼种体内及草鱼鳍单层细胞中传代繁殖,在草鱼肌肉单层细胞和性腺单层细胞中感染并出现细胞病变。病原悬液对脂溶剂乙醚敏感,耐热性强,对四环素类药物不敏感。试验结果,我们认为草鱼出血病的病原是病毒。

A redescription of Piguetiella denticulata Liang and, Xie (Oligochaeta, Tubificidae, Naidinae) from China, with a key to the genus Piguetiella

Piguetiella denticulata Liang & Xie, 1997 is redescribed based on the type series collected from the type locality, Songtao River, and streams of the Zhangjiajie Mountain in southwestern China, and specimens from several tributaries of the Yangtze River. This species is characterized by a large body size, the absence of eyespots and dorsal hair chaetae, the same size and shape of dorsal and ventral chaetae, the presence of 3-4 intermediate teeth on both ventral and dorsal chaetae, and an intestinal dilation in IX-X segments. The essential characteristics used to diagnose the genus are discussed and a key to the genus is provided.

环境因素影响草地柠条生长的主成分及典型相关分析

Principal Component and Canonical Correlation Analysis of the Environmental Factors Influencing the Growth of Caragana korshinskii Kom. in Grassland

Investigation of the gel effect in reactive extrusion processes for free radical polymerization

The gel effect in the reactive extrusion process for free radical polymerization in a closely intermeshing co-rotating twin screw extruder was investigated. First the reaction kinetic model was constructed mainly on the basis of entanglement theory. Next, numerical calculation expressions for the initiator and monomer concentrations, monomer conversion, average molecular weight and apparent viscosity were deduced. Finally, the evolution of the above variables were shown and discussed for the example of butyl methacrylate. The simulated results of the monomer conversion are in good agreement with experimental results.

Synthesis and electroluminescent properties of a novel terbium complex

A new carboxylic acid ligand (o-amino-4-hexadecane benzoic acid, AHBA) and a corresponding terbium complex (Tb(AHB)(3)) were synthesized and characterized. A multilayer electroluminescent device with poly(N-vinylcarbazole) (PVK), 2-(4-biphenyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole (PBD) and the terbium complex as emissive layer was fabricated: glass substrate/ITO/PPV/PVK:-To(AHB)(3):PBD/Alq(3)/Al. The photoluminescence (PL) and electroluminescence (EL) spectra were discussed. This EL cell exhibited characteristic emission of terbium ions with a maximum luminance of 35 cd/m(2) at 20 V. (C) 2000 Elsevier Science S.A. All rights reserved.

电感耦合等离子体原子发射光谱分析信息系统的开发 Ⅱ.系统设计与系统评价

讨论了系统设计和系统评价。首先，根据ICP-AES中有关信息在计算机中的流动、 转换、储存和处理情况设计了计算机流程图，然后根据数据库规范化的要求对数据库的概念 结构、逻辑结构和物理结构的设计作了讨论。该数据库包括了28000余条ICP发射谱线的有 关数据。运行结果表明，该系统设计合理，信息量大，且具有方便、实用的用户界面。

Synthesis and high efficiency green light-emitting diode of a soluble polymer

A soluble polymer emitting green color with high efficiency was synthesized. Bright green electroluminescence devices, both single layer and multilayer, were fabricated. The luminous efficiency was improved dramatically. Carrier injection from the electrodes to the emissive layer and concomitant green electroluminescence from the emissive layer were observed. A luminance of 920 cd/m(2) and luminous efficiency of 5.35 1m/W were achieved at a drive voltage of 15 V for the multilayer device. (C) 1997 Elsevier Science S.A.

聚甲基丙烯酸乙酯链结构核磁共振(NMR)研究

本文用~1H-NMR,~(13)C-NMR和化学位移相关谱(COSY)研究了聚甲基丙烯酸乙酯(PEMA)的链结构.虽然质子峰的重叠给谱的识别带来一些困难,但是利用H-H COSY和C-H COSY提供的信息讨论了PEMA的~1H谱和~(13)C谱中各谱峰的归属.归属β-CH_2的四元组立构序列仍有一些问题.最后计算了无规PEMA的五元组立构序列分布.

铜在水蒸气相中溶解的初步实验

近年来地质证据和少量的实验研究证实,相当量的铜可以在气相中迁移,人们认识到铜在气相中迁移是一种重要的地球化学过程,但目前关于铜在气相中溶解反应机理的研究还相当缺乏.本文通过溶解度法,在310～350℃,压力为4.2～10 MPa的条件范围内,实验研究了铜在不饱和水蒸气相中的溶解度.结果表明：水蒸气的存在大大增强了铜在气相中的溶解度;恒定温度下,铜在气相中的溶解度随着水蒸气压的增加而增大;气相中铜可能以水合物的形式存在,铜在气相中的溶解可由以下反应表述：CuClm^solid ＋nH2O^gas=CuClm·（H2O）n^gas（m=1,2）,其中水合数随着温度升高而下降,温度为310℃水合数n为～6,330℃为～5,350℃为～4.研究结果明确显示,气体溶剂H2O与铜之间的反应可大大增强铜在气相中的溶解和迁移能力。

LiNbO3∶Fe∶Rh晶体近红外非挥发全息记录

采用双中心记录方案在双掺杂LiNbO3∶Fe∶Rh晶体中实现了近红外非挥发全息记录,研究了LiNbO3∶Fe∶Rh晶体在633 nm,752 nm,799 nm波长下的全息记录性能。结果表明,在使用近红外记录光时,其记录灵敏度随敏化光强的变化趋势与双中心短波长记录时的不同。通过和LiNbO3∶Fe∶Mn等传统双掺杂铌酸锂晶体的近红外波段记录效果对比,发现同时掺杂Fe和Rh可增强晶体对近红外光的吸收,获得更高的浅中心Fe光生伏特系数,从而能够在LiNbO3∶Fe∶Rh晶体中实现近红外波段的光折变全息记录。

Distribution of CCR2-64I and SDF1-3 ' A alleles and HIV status in 7 ethnic populations of Cameroon

Limited information is available on the prevalence among rural Africans of host genetic polymorphisms conferring resistance to HIV-1 infection or slowing HIV disease progression.We report the allelic frequencies of the AIDS-related polymorphisms CCR2-64I, SDF1-3#A, and CCR5-D32 in 321 volunteers from 7 ethnic groups in Cameroon. Allelic frequencies differed among the 7 ethnic groups, ranging from 10.8% to 31.3% for CCR2-64I and 0.0% to 7.1% for SDF1-3#A. No CCR5-D32 alleles were found. HIV seroprevalence was 6.9% in the total population and peaked at younger ages in girls and women than in boys and men. Among 15- to 54-year-olds, HIV seroprevalence varied from 2.0% to 11.1% among the village populations. Conditional logistic regression analysis using data from boys and men aged 15 to 54 years showed the number of CCR2-64I alleles to be a significant risk factor for HIV seropositivity (odds ratio per allele adjusted for age and matched on ethnic group = 6.3, 95% confidence interval: 1.3–30.3); this association was not found in women. The findings are consistent with the hypothesis that CCR2-64I alleles may delay HIV disease progression without affecting susceptibility to infection among men. We did not observe this relation among women, and other factors, such as multiple pregnancies or maternal stressors (eg, breastfeeding), may have masked any protective effect of CCR2-64I alleles. Further study of this issue among women is warranted. SDF1-3#A did not differ between HIV-seropositive and HIV-seronegative individuals but wasassociated with increasing age among HIV-seronegative women, suggesting a protective effect against HIV-1 infection.