基于S-SEM的区域创新系统影响因素和路径研究

    创新是驱动经济增长和提高区域经济竞争力的一个关键因素,是保持经济持续增长的一个主要驱动力,在经济转型时期有必要研究创新影响因素及创新策略,增强区域科技创新能力。现有文献主要从创新影响因素、区域创新空间特征、区域创新效率、创新对企业的影响等方面展开研究,取得了相关研究结论和成果。区域创新系统是一个多因素交互作用复杂社会系统,并且存在空间溢出效应,因此研究区域创新系统有必要考虑不同要素之间的交互作用效应和空间溢出效应对区域创新的影响。基于相关理论分析提出九个假设,建立了广东省区域创新系统的空间结构方程模型,从创新主体、创新要素、创新政策、内部经济环境、外部经济环境、专利申请、新产品销售交互作用视角下实证分析广东省区域创新系统影响因素和路径。以广东省21个市域创新数据为样本,基于ESDA方法分析了广东省区域创新系统空间特征和空间相关性,基于空间结构方程模型研究了广东省区域创新系统影响因素和影响机制。通过研究得到以下结论：1）创新政策、创新要素和外部经济环境对广东省区域创新系统具有正向影响,创新政策影响最大;2）创新主体对广东省区域创新具有不利影响;3）内部经济环境对区域创新系统具有正向直接影响,但是考虑到各因素交互作用后对新产品销售具有不利影响;4）区域创新空间相关性对广东省区域创新系统具有正向影响。根据研究提出以下建议： 1）适当管控外资引入规模,限制有技术壁垒的外资企业,提高外资利用质量;2）改进现有高校和科研机构创新评价和激励制度,实施多元化和市场化的创新评价体系;3）建立政府主导的广东省创新系统公共平台,提供创新系统所需的信息交互、多方合作、成果交易和需求发布等功能;4）加大教育科技投入力度,营造创新氛围,增强创新人才的培养。     

放大器的容错分析

放大器的性能参数变化取决于组成它的元器件的参数变化,这些元器件的参数通常是互相独立的随机变量,收集元器件的分布参数,可计算出线路性能指标的漂移范围,如果计算出的结果超出允许范围,就应重新选择元器件的参数范围,再进行计算,直到符合要求.整个计算过程可借助概率论的有关知识来实现.这种分析和计算对放大器的设计具有一定指导意义.     

Application of time-temperature superposition method in thermal aging life prediction of shipboard cables

The life of shipboard cables will decrease due to the complex aging processes. In terms of the safety perspective, remaining life prediction of the cable is essential to maintain a reliable operation. In this paper, firstly, based on Arrhenius equation, residual life of new styrene-butadiene cable is calculated; result indicates that the degradation rate which changes with time is proportional to thermal temperature. Then second order dynamic model is adopted into the residual life prediction, combined with the time-temperature superposition method （TTSP）, and a new residual life model is proposed. According to the accelerated thermal aging experiment data and Arrhenius equation, TTSP method demonstrates to be an efficient way for life prediction, and life at normal temperature can be estimated by this model. In order to monitor the state of styrene-butadiene cable more accurately, an improved residual life model based on equivalent environment temperature of cable is proposed, and life of cable under real operation is analyzed. Result indicates that this model is credible and reliable, and it provides an important theoretical base for residual life of cables.     

基于复合模型理论的害虫测报方法研究

本文总结了害虫预测预报四个不同时期(经验预测、实验预测、统计预测及信息预测)常用的预测预报方法;概述了惯性原则下的害虫可预测预报科学依据,借助Logistic方程分析了害虫种群系统发生发展最终呈现混沌性的规律;根据害虫种群混沌系统中非线性及线性共存的特点,提出了害虫预测预报方法中运用复合模型理论的改进设想。     

椭圆型方程广义解的极大值原理

本文证明了方程的有界广义解u(除常数外),当以B(x,u,ζ)关于ζ增长的阶大于p-1(但不大于p)时,成立下列极大值原理:     

Social identification,exercise participation,and positive exercise experiences: Evidence from parkrun

Growing evidence suggests that social identities may have profound implications for physical activity participation. Real-world examinations of this relationship have, however, been lacking, with research predominantly examining intentions and hypothetical scenarios. To address this shortcoming and further advance understanding in this area, the present study tested relationships between group identification, participation, two exercise-specific outcomes (exercise-specific satisfaction and group cohesion), and a broad health indicator (life satisfaction) among individuals recruited from parkrun. Participants (N = 289) completed questionnaires measuring all variables except participants’ parkrun participation, which was objectively assessed. Structural equation modeling demonstrated that group identification was significantly associated with greater participation, exercise-specific satisfaction, group cohesion, and life satisfaction. Findings provide real-world evidence of the health-related benefits associated with forming strong social identities in exercise settings.     

基于ActiGraph GT3X监测网球运动能量消耗的研究

目的:应用ActiGraph GT3X对网球运动等非周期性运动能量消耗进行测评,建立适合网球运动能耗预测的回归方程,从而丰富ActiGraph测量体系.方法:以K4b2测量值作为校标,分别在拍柄、持拍手手腕外侧、腰部髂肌外侧、大腿中央前侧和脚踝外侧(持拍手同一侧肢体)各佩戴一个加速度计(ActiGraph GT3X),同步对网球运动中不同球速下(30 km/h、60 km/h)的原地正、反手击球,侧向移动正、反手击球,向前移动正、反手击球,侧向移动正反手交替击球和模拟自由单打的运动过程进行监测.结果:腰部、大腿和踝关节部位GT3X的EE和MET预测值存在明显低估,与K4b2测量值一致性较低;手腕和拍柄部位GT3X的EE和MET预测值存在明显高估,与K4b2测量值一致性较低;研究建立了2个网球运动能耗预测回归方程,经检验其预测值与实测值没有显著性差异.结论:运用ActiGraph GT3X对网球等隔网对抗运动项目进行监测存在显著误差,EE和MET的预测存在明显高估或低估的现象;基于ActiGraph GT3X所建立的能耗预测方程能对网球运动进行有效的运动监测.     

How does education have an impact on ethnocentrism? A structural equation analysis of cognitive,occupational status and network mechanisms

Previous studies have distinguished cognitive, occupational status and network mechanisms in the relation between education and ethnocentrism. Hypotheses on these mediating mechanisms are derived from socialization theory, realistic group threat and contact theory. In the current study we use structural equation modeling to investigate the explanatory power of these three mechanisms simultaneously. The analysis is based on a representative population survey from the Netherlands (NELLS 2009, n = 1910). The results show that more than half of the initial association between education and ethnocentrism can be attributed to cognitive ability and occupational status mechanisms. The remaining part of the overall association, however, still has to be modeled as a direct relationship between education and ethnocentrism. This direct association can be attributed either to social desirability or to a direct liberalizing effect of education on social and political attitudes. Our analysis tentatively suggests that the rise of average education levels in Western societies might lead to less ethnocentric attitudes via the cognitive sophistication mechanism.     

n元二次型特征方程的求法

给出了求n元二次型特征方程的一个重要定理,用代数方法解决了几何问题,并给出几个应用实例。     

二次不定方程3f2+3fg+g2=h2的正整数解

本文研究了二次不定方程3f^2＋3fg＋g^2=h^2给出了其所有正整数解公式.对于特例g=1和g=2利用Pell方程v2-3u2=1及不定方程3u^2-v^2=2的正整数解公式分别得到了原方程成为二元不定方程时的所有正整数解.