机载VHF通信电台闪电间接效应试验与失效分析

以某型甚高频（VHF）通信电台为试验对象开展了闪电间接效应试验及失效分析。试验结果表明,通信电台的音频响应、谐波失真、发射功率、频率稳定度和调制深度对闪电电磁脉冲的敏感性较低,而接收灵敏度较为敏感,接收灵敏度的显著退化可作为VHF通信电台在闪电作用下发生失效的典型判据之一,VHF通信电台接收功能较发射功能更容易受到闪电影响。设备失效分析表明,闪电作用下VHF通信电台发生失效的主要机理为射频前端低噪声放大器失效和射频前端滤波器对地电感器与电容器熔融烧毁。     

Cover's universal portfolio,stochastic portfolio theory,and the numéraire portfolio

Cover's celebrated theorem states that the long‐run yield of a properly chosen “universal” portfolio is almost as good as that of the best retrospectively chosen constant rebalanced portfolio. The “universality” refers to the fact that this result is model‐free, that is, not dependent on an underlying stochastic process. We extend Cover's theorem to the setting of stochastic portfolio theory: the market portfolio is taken as the numéraire, and the rebalancing rule need not be constant anymore but may depend on the current state of the stock market. By fixing a stochastic model of the stock market this model‐free result is complemented by a comparison with the numéraire portfolio. Roughly speaking, under appropriate assumptions the asymptotic growth rate coincides for the three approaches mentioned in the title of this paper. We present results in both discrete and continuous time.     

Out-of-stock,sold out,or unavailable? Framing a product outage in online retailing

Terms, such as “out-of-stock,” “sold out,” and “unavailable” are commonly used by retailers to communicate a product or brand outage. Although these terms are technically equivalent, prior research on product outage and product scarcity suggest that they may be interpreted and processed differently by consumers. The present research investigated whether the manner in which a product outage was framed elicited different consumer behavioral intentions, attributions, and perceptions in the context of online retailing. Data were collected by means of an online experiment. The experiment incorporated a hypothetical scenario approach in which research participants were asked to react to a particular combination of treatment and blocking factors. Results demonstrated that ceteris paribus, framing a product or brand outage as “sold out” produces fewer negative product and website reactions than does framing it as “out-of-stock” or “unavailable.”     

GDP growth determinants and foreign direct investment causality: the case of Iran

Given the economic conditions in Iran and the need to accelerate its economic growth, there is a rising interest in examining the variables that fuel its GDP growth. The scant literature on economic growth in Iran is composed of only a few scholarly studies that investigate this nation's GDP growth. However, none of these studies has examined the causality between GDP growth and its determining elements. The purpose of this study is: (1) to determine the economic variables that contribute to Iran's GDP per capita growth over time, and (2) to examine the causality between foreign direct investment and the relevant variables that are included in the model. To achieve these goals the study uses a model that is based on the postulates of de Mello. The results indicate that: (1) the major determinants of GDP per capita growth in Iran are value added growth and domestic investment growth; (2) there is no causal relationship between foreign direct investment growth and GDP per capita growth in Iran in either direction; and (3) there is no causal relationship between foreign direct investment growth and value added growth in Iran in either direction.     

论中国城镇住房自有率与住房保障的关系

居住是劳动力再生产的基本需要,是一种刚性需求,必须予以满足。购买住房所有权是满足居住需求的一种方式,但不是所有的消费者都有足够的支付能力购买商品化住宅。中国城镇极高的住房自有率完全是中国城镇住房保障滞后的结果,降低中国城镇住房自有率有赖于中国政府扎扎实实推进住房保障工作。由于中国各地情况不同,城镇的住房自有率不宜硬性规定,但各地住房保障水平必须有统一标准。     

基本公共服务均等化如何促进了个人创业--来自医保改革的证据

在高质量发展目标下,推行基本公共服务均等化、促进大众创业是中国经济新常态下的工作重点。基于中国城镇职工基本医疗保险在创业者和非创业者之间可得性的外生差异,本文使用中国健康与营养调查(CHNS)的微观数据,研究社会保险这一基本公共服务在创业者和非创业者之间的相对可得性如何影响个人的创业决策。我们发现,如果城镇职工基本医疗保险对于非创业者更可得,将成为“创业枷锁”,降低个人选择创业的可能性;如果城镇职工基本医疗保险对于创业者更可得,将成为“创业催化剂”,提高个人选择创业的可能性。此外,我们发现,城镇职工基本医疗保险的“创业催化剂”作用对于来自中等收入家庭和小家庭的个人更为显著,而“创业枷锁”效应则更多地影响城镇职工基本医疗保险在薪酬体系中重要性更高的个体。本文认为中国的社会保险对于大众创业具有积极正面的影响。这对于我国社会保险制度的设计和促进经济高质量发展具有重要意义。     

高铁开通与城市创新研究综述

高铁网络的建设大大提高了中国铁路运输的效率,缩短了不同城市之间的时空距离,使居民在不同城市工作和消费成为可能。同时高铁服务通过加速人口和要素在区域间的流动,对城市之间的空间联系和城市社会经济的发展产生了重要的影响。高铁在影响经济格局的同时也深刻影响了区域的创新格局,现通过梳理相关文献,整理归纳了高铁开通对城市创新的影响及其作用机制,并对现有的实证研究方法进行总结。在此基础上提出目前存在的问题,为后续的研究指明方向。     

Does environmental underperformance duration affect firms' green innovation? Evidence from China

Does the length of a firm's environmental underperformance shape its green innovation? Drawing on the behavioral theory of the firm, we argue that the duration of a firm's environmental underperformance plays an important role in shaping its green innovation activities. Using the data from Chinese publicly listed firms spanning from 2010 to 2018, we find that the duration of environmental underperformance has a U-shaped effect on a firm's green innovation, possibly due to competing short- and long-term solutions to regain legitimacy. We also find that this relationship is moderated by environmental underperformance intensity and analyst recommendation pressure. Our study contributes to the literature on green innovation and the behavioral theory of the firm. We discuss the implications for policymakers and managers.     

Disease management programs: program intervention, behavior modification, and dosage effect

Disease management programs provide highly personalized self- management support to consumers afflicted with chronic illnesses. Program interventions include the provision of health information, ongoing motivation, and support for behavior change, adherence to pharmacotherapy, development of self-efficacy, and the distribution of self-care tools. Interactions between program and patients are structured and repetitive over time. Consumer behavior change can result in measurable improvements in quality and medical cost savings from postponement or avoidance of preventable complications. We evaluated the impact on cost and quality of a comprehensive Diabetes Disease Management Program (DDMP) across ten US urban markets. A staggered implementation allowed for ten pre–post and five pair-wise comparisons. The DDMP demonstrated significant improvements in six diabetes-related quality indicators, lower cost, and a dose-response with greater than 6 months participation. We conclude that a DDMP improves quality of care and reduce overall medical costs.