围绕主题的同步交互学习支持方法的研究及工具开发

现代信息技术的发展促使世界各国进行教育信息化的改革。用IT技术辅助教学，特别是网络教学成为信息化教育的主要应用之一，它在提高教学效率的同时，缓解了知识爆炸对教育所带来的冲击，可是目前的IT技术只是用于加固传统落后的教学模式，不能从根本上改变现代教育不适应知识经济发展的社会需求，需要思考能建立适应信息社会人才需要的教育模式。 多尔的后现代课程观批判了现代主义课程观的弊端，例如封闭性、简单性和累积性，重视课程系统的开发性，课程内容的丰富性，注重学习环境的关联性。而网络教学突破教学时空的局限，提供丰富的教育资源，优化自主学习，强化教学互动。因此将后现代课程观理念融入网络教学的教学模式，用网络教学来支持后现代课程教学理念的实现，能为解决现代教学存在的问题开辟新的道路。 本文抓住后现代课程观的核心概念之一交互，通过分析目前网络教学中交互支持工具的现状，提出了围绕主题的同步交互学习支持的方法和工具实现，将后现代课程观中的交互理念与围绕主题学习的思想相结合，利用即时通信和个性化知识的再组织辅助学习中的交互过程，使得整个交互过程与学习内容紧密结合，提高了学习的效率和质量，体现了后现代课程观对课程教学的指导意义。

同步数据流模型调度序列的空间优化

提出了一种嵌入式DSP系统的存储优化方法。该方法基于同步数据流模型SDF(Synchronous Data Flow)。针对其他优化算法不适用于存在反馈环的同步数据流模型的问题,该方法为反馈环的空间优化设计实现了启发式的调度算法,并提出了将SAS(Single Appearance Schedules)和Non-SAS类型调度序列相结合的层次化的空间优化方案,为同步数据流模型调度序列的空间优化提供一个通用的解决方案。实验结果证实了该方案的有效性。

围绕主题的同步交互学习支持工具的设计与实现

提出了一种围绕主题的同步交互学习支持工具,该工具将后现代课程观中的交互理念与围绕主题学习的思想相结合,利用即时通信和个性化知识的再组织辅助学习中的交互过程,使得整个交互过程与学习内容紧密结合,有利于学习活动的深入开展,提高了学习的效率和质量,体现了后现代课程观对课程教学的指导意义。

CLIGEN非降水要素在黄土塬区的适用性评估

许多基于物理机制的水文和作物模型需要日序列气象数据来驱动,CLIGEN是为WEPP等模型产生气候输入文件的天气发生器,可以产生10个日序列气象变量来满足这种需要,但是其在中国的适用性需要进行评估。研究的目标是利用黄土高原陕西长武1957~2001年的气象数据评估CLIGEN产生非降水要素(最高温度、最低温度、露点温度、太阳辐射和风速)的能力。结果表明,CLIGEN对最高温度、最低温度和露点温度的模拟效果较好,对太阳辐射和极端气候事件的模拟效果较差,对风速的模拟效果最差。相关性检验表明CLIGEN很好地保持了气象要素的季节性,这对模拟农业生产是非常重要的;但是没有保留气象要素逐日的自相关和互相关性,进而导致产生的温度变化不符合连续渐变的规律。

围绕主题的同步交互学习支持方法的研究及工具实现

现代信息技术的发展促使世界各国进行教育信息化的改革。用IT技术辅助教学，特别是网络教学成为信息化教育的主要应用之一，它在提高教学效率的同时，缓解了知识爆炸对教育所带来的冲击，可是目前的IT技术只是用于加固传统落后的教学模式，不能从根本上改变现代教育不适应知识经济发展的社会需求，需要思考能建立适应信息社会人才需要的教育模式。 多尔的后现代课程观批判了现代主义课程观的弊端，例如封闭性、简单性和累积性，重视课程系统的开发性，课程内容的丰富性，注重学习环境的关联性。而网络教学突破教学时空的局限，提供丰富的教育资源，优化自主学习，强化教学互动。因此将后现代课程观理念融入网络教学的教学模式，用网络教学来支持后现代课程教学理念的实现，能为解决现代教学存在的问题开辟新的道路。 本文抓住后现代课程观的核心概念之一交互，通过分析目前网络教学中交互支持工具的现状，提出了围绕主题的同步交互学习支持的方法和工具实现，将后现代课程观中的交互理念与围绕主题学习的思想相结合，利用即时通信和个性化知识的再组织辅助学习中的交互过程，使得整个交互过程与学习内容紧密结合，提高了学习的效率和质量，体现了后现代课程观对课程教学的指导意义。

同步数据流可视化建模和调度优化的实现与研究

数据流是为解决数字信号处理领域应用程序设计、开发难度大等问题而提出的，和传统的控制流相比，数据流能够更加自然地描述信号处理系统，更加清晰地表达系统的并发性。应用数据流设计的信号处理系统具有较高的性能，采用数据流语言能够大大加速DSP应用程序的设计和开发。同步数据流（Synchronous Data Flow，简称SDF）基于数据流，它和数据流最大的不同在于：SDF的计算单元在编译时刻消耗数据和产生数据的数目固定，这一特点决定了采用SDF设计和建立的模型能够在编译时刻确定调度序列，使得SDF适合用于多速率信号处理系统的建模。模型化多处理器系统Modex是一个面向同步数据流的可视化建模系统，它支持开发人员运用SDF进行可视化建模、为建立的模型生成调度序列、对调度序列进行空间优化、为建立的模型生成面向目标平台的C语言代码、对模型仿真验证、对模型进行资源消耗评估、将模型映射到指定的处理器执行等。 本文介绍Modex系统的两个关键技术：可视化建模和SDF调度序列空间优化的实现和研究。文章着重介绍SDF模型描述语言的定义，图元的构建和组织，图元的图形显示，控制图元的控制器，直接操作图元的命令对象，图元和视图之间的同步机制以及图形编辑器等部分的设计和实现。Modex系统的可视化建模基于GEF(Graphical Editing Framework)，为同步数据流建模提供了丰富的可视化编辑操作，同时图元和视图之间松散耦合，可视化建模具有良好的互操作性以及扩展性。文章针对调度序列的空间优化提出了将SAS(Single Appearance Sequence）和非SAS类型调度序列相结合的思想，并基于该思想设计了生成空间优化的非SAS类型调度序列算法IAO（Increase Available Output），并结合EA(Evolutionary Approach)算法实现了面向通用,特别是存在反馈环的SDF模型的空间优化方案SGUTS（Solution for General Graph Using Two Kinds of Sequences）。SGUTS是一个层次化的优化框架，它通过聚集将一个存在反馈的模型分为上层模型和下层模型，然后采用EA、IAO算法分别为这两层模型进行优化，从而得到整个模型的优化结果。SGUTS不仅解决了存在反馈环的SDF模型空间优化问题，而且相比较其他算法，SGUTS取得了较好的优化结果。

Intense beam production of highly charged heavy ions by the superconducting electron cyclotron resonance ion source SECRAL (invited)

There has been increasing demand to provide higher beam intensity and high enough beam energy for heavy ion accelerator and some other applications, which has driven electron cyclotron resonance (ECR) ion source to produce higher charge state ions with higher beam intensity. One of development trends for highly charged ECR ion source is to build new generation ECR sources by utilization of superconducting magnet technology. SECRAL (superconducting ECR ion source with advanced design in Lanzhou) was successfully built to produce intense beams of highly charged ion for Heavy Ion Research Facility in Lanzhou (HIRFL). The ion source has been optimized to be operated at 28 GHz for its maximum performance. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. An innovative design of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28 GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6 T at injection, 2.2 T at extraction, and a radial sextupole field of 2.0 T at plasma chamber wall. During the commissioning phase at 18 GHz with a stainless steel chamber, tests with various gases and some metals have been conducted with microwave power less than 3.5 kW by two 18 GHz rf generators. It demonstrates the performance is very promising. Some record ion beam intensities have been produced, for instance, 810 e mu A of O7+, 505 e mu A of Xe20+ 306 e mu A of Xe27+, and so on. The effect of the magnetic field configuration on the ion source performance has been studied experimentally. SECRAL has been put into operation to provide highly charged ion beams for HIRFL facility since May 2007.

Observation of charge-dependent azimuthal correlations and possible local strong parity violation in heavy-ion collisions

Parity (P)-odd domains, corresponding to nontrivial topological solutions of the QCD vacuum, might be created during relativistic heavy-ion collisions. These domains are predicted to lead to charge separation of quarks along the orbital momentum of the system created in noncentral collisions. To study this effect, we investigate a three-particle mixed-harmonics azimuthal correlator which is a P-even observable, but directly sensitive to the charge-separation effect. We report measurements of this observable using the STAR detector in Au + Au and Cu + Cu collisions at root s(NN) = 200 and 62 GeV. The results are presented as a function of collision centrality, particle separation in rapidity, and particle transverse momentum. A signal consistent with several of the theoretical expectations is detected in all four data sets. We compare our results to the predictions of existing event generators and discuss in detail possible contributions from other effects that are not related to P violation.

CSR数字高频分析系统的同步采样器HDL设计

本文主要阐述了CSR数字高频分析系统的同步采样器的研究、设计和实现，该分析系统是基于软件无线电技术构建的。 本文的创新点主要在于提出了一种很好的正交同步欠采样方法，这种基于软件无线电原理的I、Q两路正交同步的采样方法，主要利用了平方律部件、一阶环路滤波器和NCO来对I、Q两路采样触发脉冲上升沿的时间差进行闭环控制，从而实现对高频信号的数据采集和处理。这种方法降低了对AD芯片采样速率要求，同时也为后续的基带信号处理提供了方便。 在整个同步采样系统的实现过程中我采用了功能强大的Matlab7.0作为通信算法的仿真平台，选用了AD6645、StratixIIEP2S60和DSP6416作为主要的硬件平台，并在SynaptiCAD和ModelSim中做出了FPGA的HDL程序设计及波形实现

碳离子辐照后细胞的适应性反应及单一时相细胞的相对生物学效应

目的：探讨低剂量碳离子辐照细胞引起的适应性反应,将低剂量效应的研究范围拓宽至高LET电离辐射领域;研究单一时相细胞经低能碳离子辐照后,存活曲线、失活截面和相对生物学效应与细胞周期各时期的关系.材料与方法：采有中国仓鼠肺V79细胞和小鼠黑色素瘤B16细胞,利用兰州近代物理研究所重离子研究装置（HIRFL）产生的碳离子,主要以细胞存活分数和细胞微核率为生物终点,探讨高LET的碳离子对V79细胞和B16细胞的低剂量效应.采用中国仓鼠卵巢细胞CHO-K和细胞同步化方法,利用德国GSI的直线加速器（Unilac）终端产生的低能碳离子,以细胞存活分数为生物终点,研究单一时相细胞经低能碳离子辐照后,存活曲线、失活截面与细胞周期各时期的关系,并与X射线的结果作了比较,得出了各时期细胞的相对生物学效应.结果：低剂量碳离子辐照细胞引起的生物学效应：1.和γ射线一样,低剂量重离子,如0.02Gy的碳离子辐照也能提高细胞的克隆形成率.这种集落形成能力的提高可能与低剂量辐照使细胞对受损DNA的修复能力增强有关.2.从细胞存活分类来看,0.02Gy预处理能使V79和B16两种细胞产生较明显的适应性反应;0.05Gy预处理引起V79细胞的适应性反应不明显,未能引起B16细胞的适应性反应.3.从细胞微核率来看,0.02Gy预处理能引起两种细胞的适应性反应;0.05Gy预处理未能引起两种细胞的适应性反应,并且已表现出协同损伤的趋势.4.高LET的碳离子和低LET射线一样,可以诱导细胞的兴奋效应或适应性反应.但诱导剂量D1不宜过高.

CSR数字射频系统的同步算法研究与应用

本文要解决CSR控制系统中扮制信号同步传送问题。HIRFL_CSR(Heavy Ion Research Facility at LanKZhou-Cooling StorageRing兰州重离子冷却储存环）是国家九八爪大科学工程之一，它的控制是一个非常庞大而复杂的系统，它由多个子系统构成，各个子系统之间的协调同步是HIRFL-CSR运行的关键，也是HIRFL-CSR从控制系统的核心问题之一。。CSR工程的同步系统包括环内各设备之间的同步，环与门前端务器的同步等等。同步系统的实现应该在保证协调同步的雄础上，还要保证整个控制系统的稳定性，实时性，准确性和抗干扰性。本文的披个解决方案是建立在直按序列扩频通信技术上的。扩频通信系统可以增强控制信一号的抗干扰性，完成f言号的可靠传输。在信号发送端，进行恭带信号的载波调制，然后经过pN码的扩频调制，进入信道传输；在接收端，先进行四码的解扩一，然后进行载波信号的解调，还原为发送端的信号。在整个过程中保证CSI又控制信号的同步，包括载波同步，位同步和群同步。本文主要工作和研究内容是CSR系统中的载波同步传输算法的不开究，设计和实现。主要工作包括（1）不叶究控制洁号在通信算法中的性能，在算法分析的基础上，使用MATLAB实现模拟控制信号通信过程，同时进行传送信号分析和噪声功率分析，测试可行性:(2)在仿真可行的情况下，把整个通信过程全部或者部分写为可以执行的C或者汇编代码，在TMS323C6711DSK板进行程序调试；（3）把可执；行的释序下我到以TrAG为接口白如醚件协尔32C6713DSP模块，实现在CSR系统中控制信号的传送。本文目的是解决控制信号的同步通愉问题，对于该问题的传输分析和同步实现以及提出的下一步研究，在C双控制I具有很重要的意义，同时也对于类似问题的解决有重要价值。

长白山红松针阔混交林CO_2通量的日变化与季节变化

Diurnal and seasonal variation of CO_2 flux above the Korean Pine and broad_leaved mixed forest in Changbai Mountain were expounded according to the measurements by eddy covariance technique. The results showed that the diurnal variation during growing season was closely correlated with photosynthetically active radiation (PAR). The forest assimilated the CO_2 in daytime and released in night. The maximum uptake occurred about 9 o'clock of local time in clear day. Assimilation was synchronous to PAR in cloudy day. The night respiration increased with increasing of shallow soil temperature. The CO_2 flux also had obviously seasonal variation that was mainly controlled by temperature. Relationship between monthly net exchange of CO_2 and monthly mean air temperature fit cubic equation. Remarkable uptake occurred in blooming growing season,May to August,and weak respiration occurred in dormant season,October to March,and relatively big release happed in October. Assimilation and respiration were nearly balanced during the transition of growing and dormant seasons. The annual carbon uptake of the ecosystem was-184 gC·m -2 .

Fluorescence analysis of phospholipase A(2) isolated from Chinese agkistrodon blomhoffii Ussurensis venom

The general and synchronous spectra of phospholipase A(2) (PLA(2)) isolated from Chinese agkistrodon blomhoffii Ussurensis snake venom were studied. The chromophores of PLA(2) were mainly contributed by tyrosine and tryptophane residues when the intervals between the excitation wavelength and the emssion waveleagth (Delta lambda) were 20nm and 75nm, respectively. The pH of buffers could change the fluorescence intensities of PLA(2) by changing the charge distribution of its amino acid chain. Ca2+ can not only increase the emission fluorescence intensity of PLA(2) but also improve the reaction rate of PLA(2) with its corresponding substrate DPPC.

An ancient C-type lectin in Chlamys farreri (CfLec-2) that mediate pathogen recognition and cellular adhesion

C-type lectins are a superfamily of Ca2+ dependent carbohydrate-recognition proteins which play significant diverse roles in nonself-recognition and clearance of invaders. In the present study, a C-type lectin (CfLec-2) from Zhikong scallop Chlamys farreri was selected to investigate its functions in innate immunity. The mRNA expression of CfLec-2 in hemocytes was significantly up-regulated (P < 0.01) after scallops were stimulated by LPS. PGN or beta-glucan, and reached the highest expression level at 12h post-stimulation, which was 72.5-, 23.6- or 43.8-fold compared with blank group, respectively. The recombinant Cflec-2 (designated as rCfLec-2) could bind LPS, PGN, mannan and zymosan in vitro, but it could not bind beta-glucan. Immunofluorescence assay with polyclonal antibody specific for Cflec-2 revealed that CfLec-2 was mainly located in the mantle, kidney and gonad. Furthermore, rCfLec-2 could bind to the surface of scallop hemocytes, and then initiated cellular adhesion and recruited hemocytes to enhance their encapsulation in vitro, and this process could be specifically blocked by anti-rCfLec-2 serum. These results collectively suggested that CfLec-2 from the primitive deuterostome C. farreri could perform two distinct immune functions, pathogen recognition and cellular adhesion synchronously, while these functions were performed by collectins and selectins in vertebrates, respectively. The synchronous functions of pathogen recognition and cellular adhesion performed by CfLec-2 tempted us to suspect that CfLec-2 was an ancient form of C-type lectin, and apparently the differentiation of these two functions mediated by C-type lectins occurred after mollusk in phylogeny. (C) 2010 Elsevier Ltd. All rights reserved.