相对论性等离子体中平均洛仑兹因子

文章给出入射激光强度与电子洛仑兹因子的关系,然后根据统计力学的方法,导出相对论等离子体中平均洛仑兹因子与温度参量之间的关系,同时利用数值计算得到其关系曲线和拟合函数.     

我国农产品冷链物流发展现状与对策研究

阐述了农产品冷链物流的概念和特性,分析了农产品冷链物流的现状和问题,并提出了相应的发展对策。     

考虑货损和碳排放的生鲜产品配送路径优化

为减少生鲜产品运输过程中的价值损耗和碳排放量,考虑生鲜产品易腐性和冷链物流高排放的特点,对货损和碳排放来源进行细化分析,发现货损主要包括物理损伤、呼吸作用引起的腐败损失和冷藏车开门导致生鲜产品加速腐败的损失,碳排放主要由车辆行驶和制冷机组在运输和卸货过程中运行所消耗的燃油产生。以固定成本、货损成本、燃油成本、碳排放成本和时间惩罚成本之和最小为目标,构建生鲜产品配送路径优化模型,并用遗传算法进行求解。算例分析表明,当总成本在可接受范围内变动时,物流企业可以为客户提供更优质的服务。     

μ 子催化核聚变中飞秒激光辐照下μ 子的运动

Introducing a superintense femtosecond laser pulse in the muon-catalyzed fusion （μCF） target, taking the mixture after fusion reaction as a overdense plasma, and based on the Newton classical equations, the paper studies the movement of muon in the plasma. Muon drift along the direction of laser propagation remains even at the end of the laser pulse. At the peak laser intensity of 1021 W/cm^2, muon goes from the skin layer into field-free matter in a short time much less than the pulse duration, before the laser pulse reaches its peak value. According to the calculated results, when the laser intensity reaches 1023 W/cm^2, the relativistic muon drift should be considered. Influence of the laser on other particles in the plasma is small. Hence, this method can avoid muon sticking to alpha effectively and reduce muon-loss probability in μCF：     

Making Electronic Resources Available to Patrons

Summary

As law schools build interactive web sites for teaching and administrative functions, law libraries must continue to develop useful and resource-rich web sites of electronic materials for their patrons. This article examines issues and practical considerations for implementing Internet and CD-ROM resources in a library and provides a basic review of the media available. Suggestions for building an Internet or Intranet site are included as is an explanation of how to use database-driven tools to create an integrated environment.     

中考改革背景下学校体育发展的热效应与冷思考

摘要：考试制度的改革,是课程改革的风向标,是课程设计的依据,同时也是对课程实施效果进行评价的有力手段。本文借助于文献资料法、专家访谈、历史研究等方法,对我国中考改革背景下学校体育发展的机遇与挑战进行了梳理和探究。中考体育改革,将会为学校体育的发展带来一定的优势和阻力,其优势表现在有利于树立正确的体育观,体育课程地位的提升,加强体育师资的建设,加速体育评价的转型等,其阻力表现在：可能形成体育学科的“应试教育”,体育考试中素质项目和技能项目的比例失衡,体育学习长期效益无法实现,体育学科特殊性和考试公平性难以体现等,针对这一情况,提出如下建议：加强政策解读,加强体育课程、场地设施资源建设,建立合理的评价机制和弱势群体保护机制,规范组织工作,以及整合校内外资源丰富体育课程内容等。     

Clinical characteristics and plasma antibody titer of patients with COVID-19 in Zhejiang,China

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which first affected humans in China on December 31, 2019 (Shi et al., 2020). Coronaviruses generally cause mild, self-limiting upper respiratory tract infections in humans, such as the common cold, pneumonia, and gastroenteritis (To et al., 2013; Berry et al., 2015; Chan et al., 2015). According to the Report of the World Health Organization (WHO)-China Joint Mission on COVID-19 (WHO, 2020), the case fatality rate of COVID-19 increases with age, while the rate among males is higher than that among females (4.7% and 2.8%, respectively). Since an effective vaccine and specific anti-viral drugs are still under development, passive immunization using the convalescent plasma (CP) of recovered COVID-19 donors may offer a suitable therapeutic strategy for severely ill patients in the meantime. So far, several studies have shown therapeutic efficacy of CP transfusion in treating COVID-19 cases. A pilot study first reported that transfusion of CP with neutralizing antibody titers above 1:640 was well tolerated and could potentially improve clinical outcomes through neutralizing viremia in severe COVID-19 cases (Chen et al., 2020). Immunoglobulin G (IgG) and IgM are the most abundant and important antibodies in protecting the human body from viral attack (Arabi et al., 2015; Marano et al., 2016). Our study aimed to understand the aspects of plasma antibody titer levels in convalescent patients, as well as assessing the clinical characteristics of normal, severely ill, and critically ill patients, and thus provide a basis for guiding CP therapy. We also hoped to find indicators which could serve as a reference in predicting the progression of the disease.     

结构自防水在高层地下室施工中的技术应用

通过工程实例，介绍了混凝土的外加剂、浇筑工艺、泌水处理、温度监测及混凝土的保湿、保温和养护等多项结构自防水的综合技术。结构自防水控制技术有效，能使地下室减少裂缝，防止渗漏，可以在类似的工程中推广应用。     

研究性教学模式在光学实验中的运用

开设研究性实验教学,是实验教学改革的一项重要内容.以一个教学案例的实施,说明学生在完成实验的过程中,从开始实验内容的确定到最后实验结果的讨论,自主学习的应用过程贯穿了整个步骤的始终,从而引发学生的科学研究兴趣,对培养学生的创新意识和实践能力具有重大意义,也对新升本科的地方院校开设研究性实验提供一些参考.     

二乙基二硫代氨基甲酸钠对冷轧钢在乙酸溶液中的缓蚀性能

采用Tafel极化曲线法和电化学交流阻抗谱法测定不同浓度缓蚀剂在0.2 mol·L-1乙酸介质中对冷轧钢的缓蚀作用.结果表明：在20℃、0.2 mol·L-1乙酸溶液中二乙基二硫代氨基甲酸钠对冷轧钢具有较好的缓蚀效果,缓蚀率随着缓蚀剂浓度的增加而增大,当缓蚀剂的浓度为3×10-3 mol·L-1时,缓蚀率达到85%,属于阴极型缓蚀剂.二乙基二硫代氨基甲酸钠在冷轧钢表面的吸附符合Langmuir吸附等温式,其吸附为自发进行的物理和化学吸附.