A New Beam Column Element of Space Framed Structures for Nonlinear Analysis of Geometric Material

An incremental virtual work equation of three dimensional(3D) beam column element is proposed based on the UL method. The geometric nonlinear tangent stiffness matrix for 3D beam column element is deduced with the consideration of warping, shear deformation and effects of moment spatial rotation. Material nonlinearity is addressed by introducing plastic hinges at the element ends. And the Orbison sectional strength is modified in order to consider the effects of torsion moment and warping. The elastic plastic tangent stiffness matrix is acquired as the element ends are in plastic phase based on the flow theory. With a case studied, it is shown that the model can be used to predict accurately the ultimate bearing capacity and instability mode of 3Dspace frames by only one or two elements, and address the effects of warping and shear deformations effectively.     

中国发展现代农业的对策选择

中国加入WTO后农业产业发展面临一个全新的国际环境。论述了发展现代农业的特征、分析了制约中国发展现代农业的症结因素,并提出了创新农业知识,建立现代农业科技体系,发展农业科技企业与农业产业化,将农业科技推向广度、深度,提高农民素质,培养知识型农民,优化生态系统,倡导持续、标准化农业和重视国际农业科技交流与合作等五个方面的对策选择。     

Newly recorded species of the genus Isohypsibius （Tardigrada; Hypsibiidae） from China

This paper reports two newly recorded species, lsohypsibius lunulatus Iharos, 1966 and lsohypsibiusprosostomus Thulin, 1928, of the genus lsohypsibius （Tardigrada; Hypsibiidae） from China. The specimens of lsohysibius lunulatus were collected from Taibai Mt （34°18′N, 107°42′E） at 2,500 m a.s.1, and those oflsohypsibius prosostomus from Taibai Mt （34°10′N, 107°35′E） at 2,000 m above sea level. All specimens are deposited at the College of Life Sciences, Shaanxi Normal University, China. A key to the Chinese species of lsohypsibius was also given.     

红枣气体射流冲击干燥收缩特性研究

Chinese jujube originated in China and has a long historical standing. China is the only country which can produce a great amount of Chinese jujube in the world. Modern research showed that the nutrition of Chinese jujube is abundant. Chinese jujube has great medicinal and food value, with high economic value and good prospects for development. Shrinkage characteristics of dates generally refer to volume shrinkage characteristics of whole dates. Large fruit and plump grain appearance of dates is the first choice of consumers to buy elements. The volume of dried jujube points to the consumer’s heart, and is an important indicator of consumers whether to buy. Jujube processing enterprises grade the date in accordance with its size, different grades dates have different value and price. Therefore, drying is the most important steps during the dates processing as it affects directly the quality of the product, and the shrinkage characteristics is the most important quality characteristic of Chinese jujube after drying. However, the traditional natural desiccation and desiccation in the drying room of the red dates has many problems. The conventional drying method for Chinese jujube has some disadvantages of severe shrinkage, long drying time and large energy consumption etc. Therefore, in order to improve the quality of dried Chinese jujube and reduce the shrinkage, it is imperative to replace the traditional drying method with the modern technologies. Air impingement drying technology was applied to dry Chinese jujube. The drying characteristics of shrinkage, moisture effective diffusivity considering shrinkage characteristics and the activation energy of Chinese jujube shrinkage were investigated under different air temperatures (55, 60, 65 and 70℃) and air velocities (6, 9, 12 and 15m/s). The dynamic changes of the regular pattern for the shrinkage characteristic of Chinese jujube in the air impingement drying process were studied, the results showed that the volume relative shrinkage ratio of Chinese jujube appeared to increase and then decrease with the increase of air temperature and air velocity. Considering shrinkage characteristics, the moisture effective diffusivity of Chinese jujube in the air impingement drying process through the Fick’s second law was obtained. The diffusivity appeared to increase and then decrease with the decrease in moisture content in dry basis of Chinese jujube. The Arrhenius equation calculated the shrinkage activation energy of the Chinese jujube was 1281kJ/mol. This research provided technical basis for shrinkage characteristics of Chinese jujube using air impingement drying technology.     

南宁市冬种番茄引进品种比较试验

对9个番茄新品种的比较试验结果表明：综合性状最好的品种是万利达,其次是美国63和英雄2号。这三个品种表现为产量高、耐寒、抗病性强,果实美观坚硬、耐贮运,商品性好,具有很强的市场竞争力,适合在南宁地区推广种植。     

海南省1株甲属虫媒病毒的分离鉴定及其血清抗体调查

1995 年,从海南省捕获的蚊虫标本中,分离到1 株病毒,编号为HYM1。该病毒以脑内感染的方式感染2～3 日龄乳鼠及3 周龄小鼠,感染后2～4 d 规律致死。在Vero-E6 细胞组织培养中可增殖,并可产生明显的病变。经理化和生物学鉴定,该病毒对酸、乙醚均敏感,抵抗5-氟脱氧尿苷和胰酶,属RNA 病毒。血清学鉴定表明,该病毒与马雅罗病毒(MAY)抗原性关系密切。从当地人血清中检到了HYM1 病毒抗体,其阳性率为3.99% 。     

杭州市森检对象和补充森检对象调查

杭州市森林面积９６２６６７ｈｍ＾２，种苗花卉木材及林产品的调运十分频繁，经１９９５￣１９９７年调查，分布国内森检对象８种、外省补充森检对象８种，根据发生、危害情况分类施策，提出控制扑灭等措施。     

甲氰胺混配乳油对柑桔全爪螨的药效试验及联合毒力测定

由甲氰菊酯（灭扫利）和水胺硫磷复配而成的22％甲氰胺混配乳油，其稀释3000～4000倍液，对柑桔全爪螨（Panonychuscitri）有良好的防治效果，室内药效达99．38％～100％。田间药效为94．70％～100％。室内毒力测定结果，甲氰胺混配乳油的LC50为21．02mg／L，灭扫利的为28.75mg／L，水胺硫磷的为153.62mg／L，甲氰胺的毒力显著高于两种单体；共毒系数达205.79，表现出显著的增效作用。     

暖通CAD信息流分析和公用数据库的研究

分析了暖通ＣＡＤ信息流的特点，提出了交互式，集成化，智能化暖通ＣＡＤ的开发构想，同时从暖通设计过程的信息流入手，开发了基于图形用户界面思想的公用数据库及其管理繁育 及基于谐波反应法的负荷计算软件。     

大面积用材林代化栽培模式技术

林业生产要达到当今经济技术条件下最大限度的速生、丰产、优质、高效稳定和持续，不仅要有良种壮苗，还要做好造林地调查与规划，做到适地适树、适时适法，这是实现林业优化栽培模式的前提与保证；同时，造林树种选择、造林时间、密度确定、种植点配置、栽培方法、林木施肥、营造混交林以及森林保护、造林地设保护带、造林地留栽补植苗，这一系列均是用材林优化栽培模式的重要技术措施。