新疆兵团地区小学科学课教师队伍建设及授课现状的调查分析——以石河子市为例

义务教育阶段新课程体系全面进入试验阶段,新课程理念对小学科学教与学提出了更高的要求。为了更好的了解小学科学课的实施现状,本研究以新疆石河子市为例,采用问卷调查、访谈和课堂观察等方法对对石河子市小学科学教师的师资队伍现状进行了调查。调查结果显示：石河子市小学科学师资匮乏;小学科学教师的专业背景较差;青年教师居多;授课能力较低;科学教师参加教研培训活动的次数少,质量低;学校对该课程重视度不高。针对这一现状提出了相应的改革建议。     

Dynamic regulation on innovation and adoption of green technology with information asymmetry

This study investigates a regulator's dynamic policy to motivate firms' research on and adoption of green technology. In the proposed model, a firm makes unobservable efforts and can hide the technology's arrival from the regulator to avoid adoption costs. We find that the optimal policy follows a simple structure and induces part-time efforts, rather than the maximal effort reported in previous studies. In particular, the regulator should offer no subsidy before the arrival of a technology report, provide a one-time subsidy contingent upon that report, and always set a termination deadline. At the deadline, the firm is forced to select an external option that is associated with social costs. The optimal report-based subsidy decreases with time. Under the optimal policy, the firm works until an effort deadline, makes no effort thereafter, and reports the technology as soon as it arrives. This study also characterizes the necessary and sufficient conditions under which the optimal policy reduces to one that leads, in terms of throughout time, to effort that is maximal or minimal. Our results indicate that policymakers should implement a policy that compensates firms more in the present and less in the future.     

上海外环线隧道消防安全事故处置对策研究

根据上海外环线公路隧道的自身状况,分析了可能发生的消防安全事故及其特点,从作战思想、战术发挥、装备应用三方面提出了处置事故的对策。     

不同使用状况下热得快电热丝的显微断口形貌分析

为了鉴别热得快在火灾发生之前是否处于干烧过热状态,模拟未使用、正常使用、干烧过热以及上述三种情形后再受火灾作用时的试验条件,获得不同使用情况下的热得快电热丝样品,采用相同的应变速率将获得的电热丝拉断并使用扫描电子显微镜观察其显微断口形貌。结果表明:相同使用状态的热得快电热丝受外热前后显微断口形貌特征变化不大,即一般火场温度对电热丝显微断口形貌的影响较小;不同使用状态下的热得快电热丝显微断口形貌特征差异明显。通过电子扫描显微镜对热得快电热丝显微断口形貌分析,可以为鉴别热得快在火灾发生前的通电状态提供一种新的方法和依据。     

基于奇异谱分析的盲源分离单通道语音增强算法研究

针对盲源分离算法无法直接对单路含噪语音信号进行分离的问题,提出一种基于奇异谱分析的盲源分离单通道语音增强算法.通过对单路含噪语音信号进行奇异谱分析,将其低频分量作为第二路观测信号,利用改进的最大信噪比盲源分离算法进行处理,从而实现语音信号和噪声的分离.实验结果表明,该算法能够有效抑制噪声,提高信噪比,起到良好的语音增强效果.     

Lot streaming with supplier–manufacturer coordination

Lot splitting refers to breaking a production lot into smaller sublots during production. Coordinating lot splitting decisions across multiple stages of a production process is a challenging task. Traditional lot splitting and lot streaming models implicitly assume that the entire system is operated and owned by the same firm, or there exists a coordinator who controls the operation of all machines in the system. In this paper, we consider the situation where the machines in a multiple‐stage production process are owned and managed by different companies. Every item in a given production lot has to go through the processing by the supplier's machine, followed by the manufacturer's machine, and so on. We develop and analyze coordination mechanisms that enable different parties in the supply chain to coordinate their lot splitting decisions so as to achieve a systemwide optimum. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004     

球齿轮行星传动结构型式与驱动机构分析

介绍了一种由渐开线球齿轮传动组成的新型空间运动行星轮系及其驱动机构,并对该机构进行了详细的结构分析和运动分析。新机构由系杆框架和一对球齿轮组成,输出轴能实现全方位的空间摆动。设计了一种空间驱动机构,用来实现系杆框架定点球面运动的姿态控制,对驱动机构的可动性进行了分析,建立了轮系输出轴的姿态角与控制电机之间的运动学模型,实现了输出轴偏转角的精确控制。     

基于六边形主域积分双谱的通信辐射源识别方法

在分析目前辐射源识别系统中常用的积分双谱参数的基础上,文章提出一种六边形主域积分双谱(HPIB)特征参数提取方法,利用双谱参数的对称性,简化积分双谱的计算,摒弃双谱矩阵中的无定义项,有效提高了积分双谱特征的计算效率。采用同型号同工作参数的10部通信电台进行识别实验,识别分类器采用概率神经网络。实验结果表明,相比传统积分双谱特征,采用HPIB特征参数可提高特征提取效率24.7%,同时由于去掉了双谱矩阵中无定义项的干扰,提高了识别系统的正确识别率。     

基于模糊综合评判的防空作战演习效果评估

防空作战演习是和平时期最贴近实战的一种训练方法,科学、合理地进行演习效果评估,对于完善演习的组织实施和提高训练效能具有重要意义.通过对防空作战演习效果影响因素的分析,建立了防空作战演习效果评估指标体系,并运用模糊综合评判方法构建了防空作战效果评估模型,实现了防空作战演习效果的定量化评估.     

末敏弹射击效能分析

通过设置目标初始条件,建立以坦克排为打击目标的仿真模型,基于末敏弹的作用原理,建立末敏弹的射击效能计算模型,并开发计算软件.通过示例计算与实弹验证,表明末敏弹射击效能计算模型具有较高的计算精度,能够满足末敏弹药量化决策的需求,对于提高新型灵巧弹药的作战运用水平具有重要的参考价值.