关于增强校长培训实效性的课程研究

开展中小学校长培训 ,提高校长的整体素质 ,是我国教育可持续发展的一项重要决策。实践告诉我们 :如果只注重国家课程的开发而忽视参训校长本人的内心需求 ,这样的培训是低效的。比较好的做法是找到国家课程与参训校长所需课程的结合点 ,按需施教 ,将培训落到实处。应在国家课程的基础上开发来自于参培者本身需要的“校长本位”课程     

Gigantic jets between a thundercloud and the ionosphere

Transient luminous events in the atmosphere, such as lighting-induced sprites and upwardly discharging blue jets, were discovered recently in the region between thunderclouds and the ionosphere. In the conventional picture, the main components of Earth's global electric circuit include thunderstorms, the conducting ionosphere, the downward fair-weather currents and the conducting Earth. Thunderstorms serve as one of the generators that drive current upward from cloud tops to the ionosphere, where the electric potential is hundreds of kilovolts higher than Earth's surface. It has not been clear, however, whether all the important components of the global circuit have even been identified. Here we report observations of five gigantic jets that establish a direct link between a thundercloud (altitude approximately 16 km) and the ionosphere at 90 km elevation. Extremely-low-frequency radio waves in four events were detected, while no cloud-to-ground lightning was observed to trigger these events. Our result indicates that the extremely-low-frequency waves were generated by negative cloud-to-ionosphere discharges, which would reduce the electrical potential between ionosphere and ground. Therefore, the conventional picture of the global electric circuit needs to be modified to include the contributions of gigantic jets and possibly sprites.     

Adaptive terminal sliding mode control for high-order nonlinear dynamic systems

An adaptive terminal sliding mode control (SMC) technique is proposed to deal with the tracking problem for a class of high-order nonlinear dynamic systems. It is shown that a function augmented sliding hyperplane can be used to develop a new terminal sliding mode for high-order nonlinear systems. A terminal SMC controller based on Lyapunov theory is designed to force the state variables of the closed-loop system to reach and remain on the terminal sliding mode, so that the output tracking error then converges to zero in finite time which can be set arbitrarily. An adaptive mechanism is introduced to estimate the unknown parameters of the upper bounds of system uncertainties. The estimates are then used as controller parameters so that the effects of uncertain dynamics can be eliminated. It is also shown that the stability of the closed-loop system can be guaranteed with the proposed control strategy. The simulation of a numerical example is provided to show the effectiveness of the new method.     

楼板裂缝问题浅析

分析楼屋面板开裂的多种原因,引进收缩梯度概念,衡量在正常配筋情况下楼板两个方面出现裂缝可能性的相对大小,应用于工程实例计算,分析结果与实际情况相符,最后提出预防楼板出现裂缝的设计要点和施工注意事项。     

浅论西方国家会计信息失真

通过考察西方治理会计信息失真的过程和经验,提出了一些治理我国会计信息失真的制度建设和制度安排的建议。     

放归鳄蜥昼间活动时间分配的初步研究

2006年5—9月,采用焦点取样法和全事件观察法对放归鳄蜥的昼间活动时间分配进行了初步研究.结果表明:在放归鳄蜥昼间活动时间分配中,在穴占61.02%±30.56%、静栖占36.72%±19.71%、运动占1.55%±0.96%、摄食占0.12%±0.08%、其他行为占0.59%±0.16%.晴天和阴天条件下放归鳄蜥的在穴、静栖、运动、摄食活动时间存在显著性差异(P﹤0.05);圈养鳄蜥和放归鳄蜥的在穴、静栖、摄食活动存在显著性差异(P﹤0.05);雌、雄及亚成体放归鳄蜥间的在穴、静栖、运动活动存在显著性差异(P﹤0.05).结果也表明,长期人工饲养对鳄蜥的摄食活动产生了较大影响.     

种植模式对稻田土壤微生物数量及活度的影响

为了明确种植模式对稻田土壤微生物的影响情况，进行了少耕和翻耕时不同种植模式对稻田土壤微生物数量及活度的影响研究，结果表明：种植马铃薯、紫云英、黑麦草、油菜、小黑麦等冬季作物能够不同程度的影响土壤中微生物的数量与活度，影响程度可以表示为马铃薯〉黑麦草〉小黑麦〉紫云英〉油菜〉冬闲。在晚稻收割期，少耕土壤中的好气性细菌、厌气性细菌、真菌、放线菌数量都多于翻耕土壤。早稻收割期翻耕比少耕的微生物活度略高，而晚稻收割期翻耕比少耕的微生物略低，这与所测的几类微生物数量的基本变化规律是一致的。少耕能激活土壤中的微生物，改良土壤。     

一个快速进化的microRNA家族

microRNAs(miRNAs)是长约22nt的非编码RNA,它可通过降解mRNA或抑制其翻译来调控基因。本文简要介绍了miRNAs的研究背景,阐述了通过比较近缘物种中非保守的miRNA基因来研究miRNAs分子进化的理由。我们的研究结果证实miRNA基因会受到达尔文正选择的影响,发生快速的进化。这一结果将为我们了解非蛋白编码基因的功能与进化提供崭新的视角。     

集成人机交互仿真系统研制与应用

基于虚拟现实技术和人机工程学原理,综合应用多通道宽屏投影拼接、光学运动跟踪和数据手套手势跟踪、Vega和Creator等许多虚拟现实软、硬件技术,构造出一个可供人与计算机中的虚拟操控系统进行实时交互的虚拟仿真环境,可对人机交互绩效进行动态、客观的测量,继而评价操控面板系统的设计质量,亦可用于各类二维操控面板的操作培训。初步实验结果验证了系统的可行性。     

试论汉字教学与提高语文素养的关系

汉字教学在语文教学中是一块"鸡肋",存在着许多问题,有必要全面提升汉字教学的系统性和可操作性。本文试图从汉字本身的规律及其延伸拓展的作用方面,探讨汉字教学与语文素养之间的关系,进而促进汉字教学的发展。