波动率的持续性：基于GARCH模型的成交量解释

文章将成交量变量合理地分解为由好、坏消息分别引致的两部分,结合GARCH模型,研究了成交量对波动率持续性的解释,并得出如下结论:成交量变量对波动率的持续性具有一定的解释力;信息对波动率的影响具有不对称性,坏消息比好消息的影响大;将成交量分解成由好、坏消息分别引致的两部分之后,能够更进一步地解释波动率的持续性。     

聚合物波导折射率渐变型Spot-size converter设计

围绕光致折射率变化聚甲基苯基硅烷高分子光波导，设计了新型的折射率渐变型Spot-size converter，可有效改善光纤与光波导的端面耦合效率．BPM仿真计算显示，耦合效率由78％提高到91％，为器件制备提供了理论依据．     

适应社会主义市场经济需要 改革高校水电管理工作初探

分析了我国高校水电管理在计划经济模式下,实行统包供给制模式的特点及弊端,认为高校水电管理工作的根本出路在于改革现行的管理体制,实行计划管理与有偿服务相结合,全面推行计量收费制.     

实现经济增长方式转换的条件和难点探讨

经济增长方式从粗放型到集约型的转换，是实现＂九五＂和２０１０年奋斗目标的关键之一。但从目前的实际和今后的发展看，要实现这一历史性的转换，还存在着许多困难，需要创造和具备一定的条件。因此，要辩证地认识经济增长方式转换中的有关理论问题，同时根据不同部门、不同行业和不同区域之间的差异情况采取结构转换的对策。     

The effects of the age and structure of population on family change]

The age structure of a population is one basic factor of population research. It is not only affected by birth, death, immigration, and marriage, but it also reflected in changes of family size. The article analyzed it from two aspects: (1) the age structure of population acts on the size and structure of the family. The younger the age structure, the larger the family size. Otherwise, it is the opposite. According to the 1982 census, 35.4% of the population was 0-14 years in rural areas, and average family size was 4.6; but in urban areas 26.0% of the population was 0-14 years and family size was 3.9. The family was characterized as a nuclear family as industrialization in economic development increased and the population aged. In the 1982 census, 64.7% were nuclear family and 6% were aging population in China. Three- generation families (or more) have decreased dramatically. The change of family size and structure is affected by change of internal family age structure. The younger population (0-14 years) is dependent and 90% live with their parents. The adult population (15-59) years are more affected by marriage, birth and social economic action. Families are established in this age period and give much more effect to fertility. The aging population (over 60) years is facing changes. They appear to be a "Defect" family because the wife or husband has passed away. They change from independent to dependent. 78.3% population over 60 years were dependent on children or social welfare, only 21.7% were independent according to the survey in Beijing Changping County.     

老年人乡村休闲养老意愿影响因素实证考察——以重庆主城都市区为例

乡村休闲养老产业发展丰富了农村产业业态,是实现乡村产业振兴的重要抓手,也是缓和城市养老压力和提高人民生活质量的重要举措。文章基于2020年9月—2020年12月重庆市主城都市区的问卷调查数据,采用logistic模型验证了影响老年人乡村休闲养老参与意愿的因素。研究结果表明家庭代际冲突、健康程度、自然环境、硬件及配套设施、服务质量均能对老年人参与意愿产生显著影响,但影响效果有所差异。结合研究结论,为推动重庆乡村休闲养老产业发展,增强参与意愿,文章提出了相应对策建议。     

农业绿色全要素生产率测度及收敛性分析——基于碳汇和碳排放双重视角CSSCI

对农业绿色全要素生产率进行科学合理的测度有助于精准把握农业碳减排潜力。本文基于2000—2019年我国省际面板数据,分别从碳汇和碳排放两个角度测度农业绿色全要素生产率,并进行了空间收敛性分析。结果表明:(1)考察期内农业绿色全要素生产率年均增速为1.1%,农业技术进步是其增长的主要动因;(2)农业绿色全要素生产率在时空演化过程中具有差异性和阶段化特征;(3)农业绿色全要素生产率呈现显著正向空间关联性,且逐渐强化,农业绿色全要素生产率较低地区发展速度要高于农业绿色全要素生产率较高地区,区域差异正在减小。研究结果对于精准评判农业碳减排潜力和碳吸收能力、实现“双碳”目标具有参考意义。     

交通基础设施对城镇建设用地效益的影响——基于京津冀城市群的空间杜宾模型分析CSSCI

交通基础设施对区域产业和经济发展有重要影响,同时也可能带来跨区域的影响,即对经济增长的影响存在溢出效应。本文以京津冀城市群为研究对象,以交通基础设施和城镇建设用地效益为主要研究变量,在理论分析的基础上,利用空间杜宾模型对两者的影响关系进行实证研究。研究结果表明:(1)交通基础设施对城镇建设用地效益的影响随交通基础设施的发展水平而变化,呈现“倒U型”的变化关系;(2)交通基础设施对城镇建设用地效益的影响存在显著的空间溢出效应;(3)京津冀城市群交通基础设施的溢出效应在城市群的不同发展阶段和不同发展水平的城市中存在异质性,2014年以前表现为正向的溢出效应,而2014年后表现为负向的溢出效应,同时,北京和天津溢出效应的影响较大,而河北的溢出效应较小。     

Inefficiency of strategy-proof allocation mechanisms in pure exchange economies

In this paper I prove that in the standard model of 2×n (n2) pure exchange economies there is no allocation mechanism that is efficient, non-inversely-dictatorial, and strategy-proof. This strengthens two previous results on this subject by Hurwicz and by Dasgupta, Hammond, and Maskin.I thank Alvin Klevorick, William Thomson, and an anonymous referee of the journal for many helpful comments.