An efficient nesting sub-domain gradient smoothing integration algorithm for Galerkin meshfree methods

·无网格法直接通过节点信息建立形函数，不依赖于节点之间的有序拓扑连接，能够建立任意高阶连续的整体协调形函数和位移场。在过去的二十多年里，无网格法得到了快速发展，在许多领域得到了成功应用，例如，裂纹扩展模拟，板壳分析，大变形模拟和断裂破坏模拟等。然而，由于无网格形函数一般不是多项式，且各个形函数的支撑域与背景积分子域通常不重合，因而伽辽金无网格法为了保证计算精度，需要在每个背景积分子域内采用高阶的高斯积分方法进行数值积分。但高阶高斯积分会明显降低无网格法的计算效率，不利于无网格法的大规模工程应用。因此，如何在保证精度的前提下提高计算效率是无网格法研究领域的一个核心问题，具有重要的理论研究和工程应...Meshfree methods are capable of constructing arbitrary order smoothing and compatible shape functions only through unstructured nodes and do not reply on elements with specific connectivity. During the past two decades, meshfree methods have experienced rapid developments and evolutions with many successful applications, i.e., crack propagation modeling, plate and shell analysis, large deformation...学位：工学硕士院系专业：建筑与土木工程学院_工程硕士(建筑与土木工程)学号：2532013115181

Research of Downhole Video Logging Instrument

本文针对测井电缆的多路视频成像测井系统中实时传送视频图像存在的质量问题，设计了一种基于光纤通信技术的井下电视测井仪器，解决了视频信号的离散、还原，数字信号的光纤传输，井下照明，镜头防油污等关键技术问题。就此，本文主要研究内容如下： 1、将数字化编码技术和光纤传输技术融合，采用AD9280高速A/D芯片对模拟视频信号进行离散，通过时分多路复用技术，开发制作了在一根光纤同时传输4路数字信号并在接收端还原成模拟视频信号的井下电视。 2、在光纤通信中，为解决电信号发射机输出的是适合于电缆传输的双极性码与光纤信道传输的是单极型码之间的匹配问题，引入了8B10B编码技术对数字信号进行码型变换，提高...Downhole video is a kind of logging instrument that taking images under the shaft. By the processing of electronic circuit, these images will reach the ground. This article is focused on the present video imaging logging system based on common logging cable is not a real-time transmission instrument. To solve this problem, this paper has designed a kind of logging instrument that based on the of o...学位：工学硕士院系专业：物理与机电工程学院_机械工程学号：1992011115278

Overmodulation strategy for flux trajectory tracking PWM and analysis of its characteristics

结合磁链轨迹跟踪的PWM生成原理,讨论了一种过调制实现策略。根据实际磁链对期望磁链的跟踪特性,分析建立了相位和径向两类误差模型;结合两类误差模型,定义评价指标:跟踪能力,并由此确定了过调制Ⅰ区和过调制Ⅱ区的分界点;从理论上证明了实现过调制极限状态六阶梯波调制的可行性,并给出其实现条件。开展了仿真验证和样机试验,结果表明新策略能有效提高直流母线电压的利用率,保持从线性调制、过调制Ⅰ区、过调制Ⅱ区直至六阶梯模式的平滑过渡,并明显抑制调制过程中的输出电压总谐波畸变率(THd)。A overmodulation strategy was studied based on the flux trajectory tracking PWM.First,phase error and radial error were analyzed based on the flux trajectory model.Then,combining two types of error model,a new evaluation for tracking capability was defined,and the demarcation point of overmodulation was determined.Then,the feasibility of six-step operation was proved theoretically,and the achievement conditions of six-step operation was given.Finally,the overmodulation strategy was theoretically analyzed,simulated and experimented.The results show that the new strategy effectually enhance the utilization rate of DC bus voltage and keep smooth transition form linear modulation,overmodulation to six-step operation,and markedly reduce the total harmonic distortion( THD) of the output voltage.国家自然科学基金(51177141); 福建省自然科学基金(2010J01310); 中央高校基本科研业务项目(2010121041); 航空基金(2012ZD68003

薄板分析的线性基梯度光滑伽辽金无网格法

薄板问题的控制方程为四阶微分方程,因而当采用伽辽金法进行分析时,形函数需要满足C~1连续性要求,且至少使用二次基函数才能保证方法的收敛性.无网格形函数虽然易于满足C~1连续性要求,但由于不是多项式,其二阶导数的计算较为复杂耗时,同时也对刚度矩阵的数值积分提出了更高的要求.本文提出了一种薄板分析的线性基梯度光滑伽辽金无网格法,该方法的基础是线性基无网格形函数的光滑梯度.在梯度光滑构造的理论框架内,无网格形函数的二阶光滑梯度可以表示为形函数一阶梯度的线性组合,因而可以提高形函数二阶梯度的计算效率.分析表明,线性基无网格形函数的光滑梯度不仅满足其固有的线性梯度一致性条件,还满足本属于二次基函数对应的额外高阶一致性条件,因此能够恰当地运用到薄板结构的伽辽金分析.此外,插值误差分析也很好地验证了线性基无网格光滑梯度的收敛特性.算例结果进一步表明,线性基梯度光滑伽辽金无网格法的收敛率与传统二次基伽辽金无网格法相当,但精度更高,同时刚度矩阵所需的高斯积分点数明显减少.国家自然科学基金资助项目(11772280,11472233

薄板分析的线性基梯度光滑伽辽金无网格法

薄板问题的控制方程为四阶微分方程,因而当采用伽辽金法进行分析时,形函数需要满足C1连续性要求,且至少使用二次基函数才能保证方法的收敛性。无网格形函数虽然易于满足C1连续性要求,但由于不是多项式,其二阶导数的计算较为复杂耗时,同时也对刚度矩阵的数值积分提出了更高的要求。本文提出了一种薄板分析的线性基梯度光滑伽辽金无网格法,该方法的基础是线性基无网格形函数的光滑梯度。在梯度光滑构造的理论框架内,无网格形函数的二阶光滑梯度可以表示为形函数一阶梯度的线性组合,因而可以提高形函数二阶梯度的计算效率。分析表明,线性基无网格形函数的光滑梯度不仅满足其固有的线性梯度一致性条件,还满足本属于二次基函数对应的额外高阶一致性条件,因此能够恰当地运用到薄板结构的伽辽金分析。此外,插值误差分析也很好地验证了线性基无网格光滑梯度的收敛特性。算例结果进一步表明,线性基梯度光滑伽辽金无网格法的收敛率与传统二次基伽辽金无网格法相当,但精度更高,同时刚度矩阵所需的高斯积分点数明显减少

Pressure Measurement of Vacuum Insulation Panel with Infrared Spectroscopy

真空绝热板(VIP)主要是依靠其内部真空度来提高其绝热性能的,由于导热系数是表征真空绝热板绝热性能最重要的物性参数,准确测量出真空绝热板的导热系数,有助于将真空绝热板应用于需要绝热保温的场合并估算出其热负荷情况,为系统选择制冷设备或加热设备提供依据。在对真空绝热板真空度检测技术的研究中,本文致力于研究一种基于热红外技术的真空绝热板真空度检测方法,主要采用埋入热辐射器件、能量由外部无损耦合提供、使用红外热图像处理技术并结合电路控制系统等实现对真空绝热板的真空度检测。实验表明,红外检测技术用于测量真空度是可行的、检测速度快、检测结果可靠;对热红外检测技术的研究有利于推动国内真空度快速检测技术的发展。A novel technique has been successfully developed to non-destructively evaluate the pressure in the vacuum insulation panel( VIP),fabricated on industrial scale.In the newly-developed technique,the heat radiation device,embedded in the VIP and energized in non-contact mode by the lab-built,external power-supply,is capable of emitting infrared( IR) light.The internal pressure can be indirectly estimated via data analysis of the spectrum and image acquired with a digital IR camera.The impact of the time evolution of the pressure on the IR image was experimentally and analytically simulated.The preliminary results show that the newly-developed,IR pressure-probe is feasible to measure rapidly the VIP pressure with high reliability.Further improvement of its measurement accuracy was under way

一种支持软件项目资源调度的任务人员优化匹配方法

依赖主观判断和个人经验的任务人员分配方法具有不稳定性和不可靠性,直接导致较低的人力资源利用效率。已有的资源调度方法对人力资源的复杂性和能力差异性考虑不足。提出了一种支持软件项目资源调度的任务人员优化匹配方法。方法将心理学与软件项目管理进行结合,通过挖掘人力资源的性格能力属性,综合技术能力属性,对任务人员的匹配过程进行优化。工具和实验表明,方法可为项目管理人员进行任务分配时提供有效的决策支持

An International Study on the Relationship between Fertility Rate and Income Inequality under the Constraint of Intergenerational Mobility

收入不平等问题和人口生育率过低问题是当下中国面临的两大难题,但目前理论界关于人口因素与收入不平等关系的研究,很少从生育率视角来考察以及考虑代际收入流动在其中的作用。文章从理论与经验两个方面来考察生育率对收入不平等的影响,理论模型表明:在关于代际收入流动的假设下,一个经济体中生育率的提高会使穷人比重提高,进而拉大收入不平等。进一步地,文章利用1970-2011年76个国家(地区)面板数据的经验研究发现:(1)总和生育率的提高会拉大收入不平等,如果每个妇女平均多生育一个孩子,将会使基尼系数增加0.025;(2)以出生率作为总和生育率替代指标的实证结果与基准结果基本一致,这说明不同生育率测算指标高度相关且可相互替代;(3)对于代际收入流动弹性越高、收入水平越低或生育率越高的国家(地区),其生育率提高对收入不平等的拉大作用越大。文章关于生育率对收入不平等影响的作用机制和异质性特征的考察,对于我国如何在实施"全面二孩"政策下寻求应对严峻的收入分配问题之策提供了国际经验和启示。The problems of income inequality and low fertility rate are two major challenges in China nowadays.However,there are few researches about the relationship between demographic factor and income inequality from the perspective of fertility rate and exploring the role of intergenerational income mobility in the academia.This paper theoretically and empirically explores the impact of fertility rate on income inequality.The theoretical analysis shows that an increase in fertility rate will increase the proportion of the poor,thus enlarging the income inequality in an economy under the assumption of the intergenerational income mobility.Furthermore,using a cross-country panel dataset covering 76 countries and regions between 1970 and 2011,our empirical findings show as follows：firstly,an increase in total fertility rate will lead to a rise in income inequality;specifically speaking,if each woman has one more child on average,the Gini coefficient will increase by 0.025;secondly,the results by using the birth rate as a proxy indicator for total fertility rate are identical with the basic results,which mean that different measurement indicators for fertility rate are highly correlated with each other and can be mutually substituted;thirdly,total fertility rate has a greater impact on income inequality in countries with higher level of intergenerational income mobility elasticity,lower level of income,or higher level of total fertility rate.The analysis of the mechanism and heterogeneous characteristics of the effect of fertility rate on income inequality provides international experience and enlightenment for how to deal with the serious income distribution issue under the universal two-child policy.国家社会科学基金青年项目(16CRK017)

硫化镉前驱体的合成及其在太阳能电池中的应用

本发明公开了硫化镉前驱体的合成及其在太阳能电池中的应用，具体地，本发明公开了一种含镉，不同碳链的黄原酸作为第一配体和1,10–菲啰啉（或其衍生物）作为第二配体的小分子半导体材料，其制备方法，及其在太阳能电池中的应用。该材料具有式1所示的结构，其中，各基团的定义如说明书中所述。用所述的式1化合物制备的半导体材料性能优越，非常适合用于太阳能电池部件的制造和生产