Flood frequency and routing processes at a confluence of the middle Yellow River in China

IEECAS SKLLQG

西安加速器质谱中心多核素分析的加速器质谱仪

IEECAS SKLLQG

Multiple expansions of C-4 plant biomass in East Asia since 7 Ma coupled with strengthened monsoon circulation

IEECAS SKLLQG

HIRFL-CSR电源数字控制系统硬件平台设计

论述用于兰州重离子加速器冷却存储环(HIRFL-CSR)磁铁电源控制系统的数字控制系统硬件平台设计。该系统基于1mmBGA封装的ALTER corporation的cycloneⅢFPGA芯片,嵌入运行数字调节器软件算法,满足了针对具体被控对象参数要求的调节控制。用ARM(Advanced RISC Machines)作调节控制系统的核心处理器,完成系统的多线程任务处理;同时嵌入千兆光纤接口,实现外接DSP板处理数据的直接传输,提高了系统的实时性。该硬件平台实现了HIRFL-CSR电源系统的稳定、可靠和实时控制。

基于SHAW模型的黄土高原半干旱区农田土壤水分动态模拟

黄土高原半干旱区土壤蒸发强烈,准确地掌握土壤水分动态对于旱地农业水分管理至关重要。应用基于物理基础的一维水热耦合SHAW(The Simultaneous Heat and Water)模型,模拟了陕西子洲岔巴沟流域1964~1967年土壤水分和土壤蒸发的动态特征,以及神木六道沟流域2006年坡地和梯田土壤水分变化。结果表明,除表层土壤水分模拟结果偏差较大,其他土层模拟值与实测值基本吻合,模拟期土壤水分模拟的相对平均绝对误差(Relatively Mean Absolutely Error,RMAE)为5.2%~11.4%。1964~1967年土壤累积蒸发量模拟值与实测值平均相对偏差为0.8%~6.1%,土壤蒸发的模拟值与实测值较为一致。因此,SHAW模型可以用于黄土高原半干旱区农田土壤水分动态规律研究。

基于智能体的儿童协作讲故事系统

讲故事作为学校和家庭教育儿童的有效手段，一直是国内外各研究机构的研究热点。目前的很多儿童讲故事软件以各种形式为儿童提供了故事创作工具，但是它们大多不能让儿童相互协作，也没有提供讲故事中的智能辅助。多用户输入技术具有节约设备成本和提高合作效率的优点，故事中的智能体具有动态地生成故事的功能，但是这两者在儿童软件方面的应用并不多，在儿童讲故事中引入这两个技术，可以提高讲故事的益智性与娱乐性。 在此研究背景下，本文研究多用户输入技术与故事中的智能体技术，结合笔式用户界面的优势，以儿童用户为中心，开发基于智能体的儿童协作讲故事系统。让多个儿童既能协同进行故事创作，也能与故事智能体一起交互地创作非线性的故事，享受合作与创作的乐趣。 本文的主要工作如下： 1、多用户输入研究 分离了各用户的输入数据，设计多用户输入下的事件处理机制，研究了多用户输入下的界面支持，并结合笔式用户界面，设计了常用命令的输入手势，使得系统接入多个指点输入设备后，就能支持多个用户共同进行操作，并给予用户各自的响应。 2、故事中智能体的研究 归纳了讲故事中使用的知识库，设计了情节智能体来保持故事的连贯性与管理用户的参与，设计了角色智能体来指导角色完成任务并管理情绪，使得在用户的参与下，智能体能根据故事目标，动态地生成故事。 3、故事显示的设计 研究了已有的适合儿童的角色设计工具，并在此基础上设计了故事显示的方法，在三维的故事世界中，采用角色设计工具的作品作为故事素材，加入角色与动作的渲染，将儿童讲故事的结果可视化。 4、系统的设计与实现 在以上研究的基础上，设计了多用户输入的识别方法、数据分析过程和事件处理机制，设计了知识库、情节智能体、角色智能体及它们三者之间的交互接口，结合儿童讲故事的应用，实现基于智能体的儿童协作讲故事系统。

Preparation and luminescence properties of Ce3+ and/or Tb3+ doped LaPO4 nanofibers and microbelts by electrospinning

Ce3+ and/or Tb3+ doped LaPO4 nanofibers and microbelts have been prepared by a combination method of sol-gel process and electrospinning. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL), low voltage cathodoluminescence (CL) and time-resolved emission spectra as well as kinetic decays were used to characterize the resulting samples. SEM and TEM results indicate the as-formed precursor fibers and belts are smooth. and the as-prepared nanofibers and microbelts consist of nanoparticles. The doped rare-earth ions show their characteristic emission under ultraviolet excitation, i.e. Ce3+ 5d-4f and Tb3+ D-5(4)-F-7(j) (J = 6-3) transitions, respectively. The energy transfer process from Ce3+ to Tb3+ in LaPO4:Ce3+, Tb3+ nanofibers was further studied by the time-resolved emission spectra.

小议数字“两”、“二”和“2"的用法

列举若干实例，从习惯用法、具体含义和特殊用法讨论数字“两”、“二”和“2”的使用方法。

Preparation and mass spectrometric study of egg yolk antibody (IgY) against rabies virus

Rabies virus was used as the antigen to immunize laying chickens. Anti-rabies virus immunoglobulin Y(IgY) was isolated from yolks of the eggs laid by these chickens using a two-step salt precipitation and one-step gel filtration protocol. The purified IgY was reduced with dithiothreitol, and heavy chains (HC) and light chains (LC) were obtained. In addition, the purified IgY was digested with pepsin and the fragment with specific antigen binding properties (Fab) was produced. Using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOFMS), the average molecular weights of IgY, HC, LC, and Fab were determined as 167 250, 65 105, 18 660, and 45,359 Da, respectively. IgY has two structural differences compared with mammalian IgGs. First, the molecular weight of the heavy chain of IgY is larger than that of its mammalian counterpart, while the molecular weight of the light chain of IgY is smaller. Second, upon pepsin digestion, anti-rabies virus IgY is degraded into Feb, in contrast to mammalian IgG, which has been reported to be degraded into F(ab')(2) under the same conditions. Copyright (C) 2001 John Wiley & Sons, Ltd.

A study of the effect of shell content on the mechanical properties of polycarbonate/poly(butyl acrylate)-cs-poly(methyl methacrylate) blends

The toughening effect of the shell content of a core-shell latex polymer poly(butyl acrylate) (PBA)-cs-poly(methyl methacrylate) (PMMA) on its blends with polycarbonate (PC) was studied. The changes of mechanical properties, morphology, and compatibility of the blends of PC/PBA-cs-PMMA with the change of the shell thickness of PBA-cs-PMMA were investigated. It is interesting to notice that mechanical properties of the blends are very sensitive to the shell thickness (i.e., shell content), and that there is a possibility to adjust the impact and tensile properties of the blend by selecting a PBA-cs-PMMA with a proper core/shell ratio. Hence, a modified PC material with balanced mechanical properties may be prepared.