BTOPMC/SCAU分布式流域水文模型原理和系统设计

BTOPMC(block-wise use of TOPMODEL(TOPgraphic MODEL,基于地形的水文模型)with the Muskingum-Cunge method,分块应用TOPMODEL和马斯京根-康吉汇流方法)是一个具有较强物理基础的分布式流域水文模型,主要用于教学和流域研究,模型有待软件化,以便用于流域作业预报和水资源管理。该文采用多层架构体系设计了该模型的计算机系统,形成了BTOPMC/SCAU(south china agricultural university),系统由数据层、模型层、通信层、数据表达层和用户操作层组成,运行环境采用客户端/服务端模式。提供手动和自动2种参数率定模式,自动率定采用SCE-UA(shuffled complex evolution developed at university of arizona)全局最优算法,内置7种目标函数。采用Open MP(open multi-processing,开放式多处理)多核并发编程技术在产汇流模块实现了多核并行计算。系统为流域水文作业预报和水资源管理提供了精致的方法和简便工具。     

聚合物基/稻壳粉复合材料的表面改性研究

使用JC2000A型接触角测量仪测试并研究了蒸馏水和甘油两种液体在稻壳粉填充聚乙烯(PE)、聚丙烯(PP)、聚氯乙烯(PVC)复合材料表面的接触角.研究表明:通过酸碱处理可明显改变接触角及其随时间变化的规律;其中效果最好的是以水作为探测液时,经酸处理后的PE/稻壳粉复合材料.通过方差分析得知表面改性处理方式对接触角有相当显著的影响.     

基于Master CAM和Pro/E的齿轮快速精确建模及仿真分析基于MasterCAM和Pro/E的齿轮快速精确建模及仿真分析

以外啮合直齿圆柱齿轮为例,介绍了利用Master CAM和Pro/E进行齿轮精确建模,并根据实际工况条件,采用Pro/E的Mechanica对所设计的齿轮进行仿真分析。结果表明,采用此方法可快捷、精确地完成齿轮类零件的设计。     

木质陶瓷复合材料的制备与性能分析

综述了几种典型基材木陶瓷材料的不同制备方法与性能,对不同基材材料制备木陶瓷的方法做了论述,介绍了不同材料制备的木陶瓷电学性能、力学性能和摩擦性能。为材料的制造方法与结构功能设计提供了新思路,并对其发展前景进行了展望。     

铅胁迫下菲白竹的矿质营养吸收和分配

随着矿产、化工、冶金等工业排放的"三废"剧增以及汽车尾气排放量的增加,人类生存环境中的土壤、水体以及空气受重金属污染现象日趋严重,有些重金属通过食物链在人体内蓄积,严重危害人体健康(Kambhampati et al.,2003).铅是一种常见的重金属,全球每年消耗量约为400万t,但仅有1/4得到回收利用,其余大部分都以不同形式进入环境引起污染(李建正,2006).     

木材-橡胶功能性复合材料制造工艺主要影响因素的交互作用和相关性(英文)

确定聚异氰酸酯(PMDI)与脲醛胶(UF)混合胶黏剂胶接木材与废旧轮胎橡胶制备功能性复合材料工艺的可行性;研究木材-橡胶功能性复合材料制备工艺的主要影响因素(密度、热压时间和温度)对复合材料力学性能:内结合强度(IB)、静曲强度(MOR)、弹性模量(MOE)作用的相关性。采用Design-Expert的响应曲面法分析各主要因子密度、温度、时间对力学性能影响的变化规律,优化各因子,并揭示相互影响和作用机制。结果表明:密度对材料的力学强度有显著性的影响,热压温度与时间的交互作用同样对材料的力学性能影响显著;采用低成本的PMDI/UF混合胶黏剂能够很好地胶结木材和橡胶制备功能性复合材料;获得木材-橡胶复合材料最佳优化工艺:密度1000kg·m-3、热压时间300s、热压温度170℃。利用电子扫描电镜(SEM)揭示了木材-橡胶功能性复合材料的微观结构,并进行界面结构分析。对PMDI/UF胶黏剂胶接橡胶和木材的物理化学胶合机制进行全面系统的分析。     

Intestinal absorption of forsythoside A in different compositions of Shuang-Huang-Lian

Shuang-Huang-Lian (SHL), a traditional Chinese formula containing Lonicerae japonicae flos (LJF), Scutellariae radix (SR) and Forsythiae fructus (FF), is commonly used to treat acute upper respiratory tract infection, acute bronchitis and light pneumonia. Forsythoside A is one of the main active ingredients in Forsythiae fructus, a key herb in SHL. In the present study, effects of different compositions in SHL on the intestinal absorption of forsythoside A were investigated. The observations from in situ intestinal circulation model showed that A/%(h^− 1) of forsythoside A in FF + LSF, FF + SR and SHL were all reduced greatly compared with that in FF. However, in pharmacokinetics study, C_max and AUC_0 → 1440 of forsythoside A all increased and T_1/2 prolonged in SHL, FF + LJF and FF + SR compared with FF. The results indicated that the different compositions of SHL decreased absorption but increased bioavailability of forsythoside A, which may be related to its metabolism inhibited in intestine or liver.     

Nitrogen dynamics during ecosystem development in tropical forest restoration

We considered whether ecological restoration using high diversity of native tree species serves to restore nitrogen dynamics in the Brazilian Atlantic Forest. We measured δ¹⁵N and N content in green foliage and soil; vegetation N:P ratio; and soil N mineralization in a preserved natural forest and restored forests of ages 21 and 52 years. Green foliage δ¹⁵N values, N content, N:P ratio, inorganic N and net mineralization and nitrification rates were all higher, the older the forest. Our findings indicate that the recuperation of N cycling has not been achieved yet in the restored forests even after 52 years, but show that they are following a trajectory of development that is characterized by their N cycling intensity becoming similar to a natural mature forest of the same original forest formation. This study demonstrated that some young restored forests are more limited by N compared to mature natural forests. We document that the recuperation of N cycling in tropical forests can be achieved through ecological restoration actions.     

Coast live oak, Quercus agrifolia, susceptibility and response to goldspotted oak borer, Agrilus auroguttatus, injury in southern California

Oak mortality is often associated with a complex of decline factors. We describe the morphological and physiological responses of coast live oak, Quercus agrifolia Née, in California to an invasive insect, the goldspotted oak borer (GSOB), Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), and evaluate drought as a potential inciting factor. Morphological traits of 356 trees were assessed and physiological traits of 70 of these were monitored intensively over one growing season. Morphological characteristics of tree health included crown thinning and dieback; bole staining resulting from larval feeding; density of GSOB adult exit holes; and holes caused by woodpecker feeding. These characteristics were used to rank GSOB infestation/injury into four classes, and taken together, they explained 87% of the variation in a principal component analysis. Drought stress on various size/age and infestation classes of Q. agrifolia was measured by assessing branchlet pre-dawn and solar noon xylem water potential, leaf cell turgor potential, and water use efficiency over one growing season. Both morphological and physiological traits were highly variable in mature and old growth trees. Early summer plant water status (branchlet xylem water potential and water use efficiency) was similar between uninfested and newly colonized trees, suggesting that GSOB are not pre-selecting drought-stressed Q. agrifolia for oviposition. By late summer, leaf water and cell turgor potentials were lower in infested than in uninfested mature trees, suggesting that GSOB infestation causes drought stress in these trees. Among the tree size/age classes, infested old growth trees exhibited the greatest change in water use efficiency over the growing season, and showed greater morphological injury symptoms of decline than infested mature trees. Morphological attributes of decline in Q. agrifolia associated with GSOB were correlated weakly with increasing physiological drought stress among infestation classes of trees. We propose that the collection of morphological responses of Q. agrifolia to GSOB described here can be used to monitor the future expansion of the GSOB distribution as well as the GSOB-induced decline of Q. agrifolia in California.