关于Mordell方程y^2=x^3＋k

设l,l1,l2,…,ls为任意整数,n为正整数,n1,n2,…,ns为任意非负整数．用初等数论方法证明了：如果k满足k=（4l＋2）^3-Пi=1^s（4li＋1）^2ni或k=（4l＋3）^3-2^2nПi=1^s（4li＋1）^2ni,则Mordell方程y^2=x^3＋k无整数解．     

二维量子阱中单电子量子比特的性质

通过求解能量本征方程,得到弱磁场作用下的二维势阱中电子的本征能量及其波函数,进而以基态和第一激发态波函数构造了一个量子比特.数值计算结果表明,量子比特内电子的空间概率密度随空间坐标和时间的变化而变化,在阱的边缘处出现的概率值为零,在其他位置相对较大;各个空间点的概率密度均随时间做周期振荡,振荡周期与阱宽有关,与外磁场无关,它随阱宽的增加而增大.     

粘性层流流体速度分布的数值计算方法

介绍了如何运用数值计算方法来求解粘性层流流体的速度分布,通过坐标系转化理论、连续性方程、Navier-Stokes方程导出有关速度的非线性微分方程,运用数值计算方法分别对对称性速度流体和非对称性速度流体进行数值求解,其结果对深入了解粘性流体运动的基本规律有着重要的现实意义。     

Childhood trauma as a mediator between emotional intelligence and recidivism in male offenders

BackgroundPrior researches have implicated a relationship of recidivism with childhood trauma (CT) and emotional intelligence (EI). However, the internal mechanism by which CT and EI influence the recidivism has not been examined.ObjectiveThis study aimed to map the road from CT and EI to recidivism in Chinese male offenders.Participants and settingThree thousand one hundred and eighty-one Chinese adult male offenders participated in this study and completed Childhood Trauma Questionnaire (CTQ) and Wong Law Emotional Intelligence Scale (WLEIS). Recidivism was quantified by the number of convictions according to official records.MethodsAfter controlling for age, education levels, family criminal history, and nature of offence, logistic regression sanalysis was performed to examine the effects of CT and EI on severity of recidivism. Structural Equation Modeling (SEM) was applied to explore the mediation model between CT, EI and recidivism.ResultsLogistic regression model shows a significant effect of CT (OR = 1.008, p < 0.01), rather than EI, on recidivism. SEM supported a full mediating effect of CT in the relationship between EI and severity of recidivism.ConclusionsOur findings suggest that EI has no direct effect on the recidivism, but exerts indirect influence on the recidivism through the mediating role of childhood trauma.     

Using students’ feedback for teacher education: measurement invariance across pre-service teacher-rated and student-rated aspects of quality of teaching

Comparing self-perceived quality of teaching to students’ perception can be used in higher education to improve the quality of teaching of pre-service teachers in teacher education. However, comparing these measurements from different perspectives is only meaningful if the same constructs are being measured. To shed light on this comparison’s meaningfulness, we scrutinised whether aspects of quality of teaching are measured in the same way across pre-service teachers and their students by means of measurement invariance analyses. To do so, 272 pre-service teachers in teacher education rated aspects of their quality of teaching, and were rated by their 4851 students. Measurement invariance across these perspectives was tested in multilevel structural equation models. Strong measurement invariance held for two aspects of quality of teaching; for the third, one item lacked weak measurement invariance. Pre-service teachers perceived their quality of teaching lower than their students. In conclusion, aspects of quality of teaching can be compared across perspectives, and teacher education should encourage pre-service teachers to use students’ feedback as a valuable resource for improving their quality of teaching.     

一类双曲型方程的有限差分法

利用有限差分法求解波动方程边值问题,得到了相应的稳定性分析,并进行了数值模拟.模拟结果表明;该方法求得的数值解有较高的精度和较快的运行速度.     

Mobile users’ information privacy concerns and the role of app permission requests

Recent privacy-related incidents of mobile services have shown that app stores and providers face the challenge of mobile users’ information privacy concerns, which can prevent users from installing mobile apps or induce them to uninstall an app. In this paper, we investigate the role of app permission requests and compare the impact on privacy concerns with other antecedents of information privacy concerns, i.e., prior privacy experience, computer anxiety, and perceived control. To test these effects empirically, we conducted an online survey with 775 participants. Results of our structural equation modeling show that prior privacy experience, computer anxiety, and perceived control have significant effects on privacy concerns. However, concerns for app permission requests have approximately twice as much predictive value than the other factors put together to explain mobile users’ overall information privacy concerns. We expect that our findings can provide a theoretical contribution for future mobile privacy research as well as practical implications for app stores and providers.     

森林体验教育活动对城市公众环境负责任行为的影响

全球可持续发展和中国生态文明教育对激发公众环境意识、引导公众环境负责任行为提出了更高要求,尤其对于城市公众的影响意义重大。北京市率先引入森林体验教育理念,发挥森林生态系统文化服务功能,开展丰富多彩的森林体验教育活动。本文基于心流理论及其他文献,构建了森林体验教育活动对引导公众环境负责任行为影响的概念模型,以北京为例调查了676位参与活动的公众,运用结构方程模型方法验证了参与动机（活动前）、活动体验（活动中）对环境负责任行为（活动后）的影响机理。研究结果表明活动体验对引导公众环境负责任行为的影响是显著且正向的,并且是参与动机和环境负责任行为之间关系的完全中介变量。这一结论说明了森林体验教育活动的有效性和必要性,为进一步提升北京市活动效果和推动中国其他地区类似活动提供了理论支撑和实践参考。     

农户分化对农地功能供给多样化的影响路径

推动农地的多功能利用是顺应“功能拓展”这一现代农业发展的客观规律,实现乡村振兴战略的重要基础。社会化小农阶段,农户渐趋分化,其意愿行为的复杂性直接影响到农地功能供给的多样性。本文通过归纳社会化小农的行为特征,以“农地多功能需求的农户响应”为中介因素,构建了农户分化影响农地功能供给多样化的路径分析概念模型,并使用结构方程（SEM）对该模型进行拟合,分析农户分化对农地功能供给多样化的直接效应及其经由“农地多功能需求的农户响应”这一中介因素对农地功能供给多样化的间接效应的大小、方向及影响因素,以探索小农社会化的趋势下,农户分化对农地多功能供给的影响及其影响路径。在湖北省黄陂、新州、鄂州、江夏、通山、蔡甸共6个县（区）的实证研究表明：①农户分化对农地功能供给的多样化兼有直接和间接的负向影响,即农户拥有的生计资本越多,则其供给的农地功能的多样性越低。②农户分化对农地功能供给多样化的直接负效应主要源于农业生产条件的外部化造成的某些生产要素替代,如优质劳动力的流失引起的劳动力要素和其化肥、农药等要素之间的替代造成的农地生态功能的弱化;③间接负效应则源于社会化小农趋势下渗透型、联结型、物质型3类生产要素的失配,即3类要素的投入没有达成激励相容,从而影响了农地多功能的产出效率。基于以上研究结果提出如下建议以推动农地的多功能利用：①重视新型的联接型及渗透型生产要素的投入,并且使两者与实物型生产要素达到激励相容。②拓宽传统的农地利用方式,加深农户对农地外部化生产条件的认知,并通过社保、财政等手段缓解农户对外部化生产条件的依赖,吸引优质农业劳动力回归;③完善农地流转政策,搭建农地流转信息交流平台,推动农地的完全流转。     

二次方三项式线性齐次微分方程的解法

通过把线性齐次微分方程x2y(n) 2nxy(n-1) n(n-1)y(n-2)=0化为可逐次积分的线性微分方程,找出了它的通解形式,给出了严格的证明,并将其推广,得到x2y(n) (x2 2nx)y(n-1) [2(n-1)x n(n-1)]y(n-2) (n-1)(n-2)y(n-3)=0的通解.