An Empirical Analysis on the Influence Factors of the Subjective Well-being in the Domestic Elderly

本文的研究基于以下背景：（1）随着物质财富的不断积累和文明程度的日益提高，幸福的内涵逐渐丰富起来，人们逐渐将焦点从解决温饱问题转向追求精神层面的富足。幸福关系到每一个个体的生存与发展，实现幸福生活是生命个体的终极目标，也是实现“中国梦”的本质要求；（2）随着全球老龄化进程的加快，人口老龄化已经成为中国面临的重大社会问题之一，超过我国十分之一人口比例的老龄群体的生活问题应该引起广泛关注。因此，研究老年人主观幸福感的影响因素，提出增加老年人幸福感的政策建议，对于促进家庭和社会的和谐发展具有重要的意义。本文使用2011-2012年中国老年健康影响因素跟踪调查数据(CLHLS)，通过描述统计、因子分析...The study is based on the following backgrounds:(1)With the prosperity of material wealth and civilization, the meaning of happiness has become richer. Gradually, people put focus from solving the problem of food and clothing to pursuing the spiritual wealth.Happiness is related to the survival and development of every single citizen. Realizing the happy life is not only the ultimate aim of the in...学位：经济学硕士院系专业：经济学院_政治经济学学号：1532014115212

Time resolved measurements of droplet preferential concentration in homogeneous isotropic turbulence without mean flow

An experimental investigation of the time-dependent spatial distribution of droplet concentration in a "box" of stationary homogeneous and isotropic turbulence without mean flow was performed for polydispersed droplet clouds with a wide range of mean droplet diameters and droplet size distributions, characterized by a representative Stokes number, based on the droplet arithmetic diameter and the Kolmogorov time scale of the flow, varying between 0.2 and 6, and for turbulent Reynolds numbers of 98, 127, 147, and 235. A novel morphological tracking scheme was used to provide temporal tracking of droplet clusters according to cluster morphological features. The tracking scheme was based on Voronoi space tessellation, multivariate kernel density estimation, and mean shift feature space tracking. The developed tracking scheme was used to establish the relationship between the morphological features of droplet clusters, i.e., number of clusters per unit area and cluster length scales, and the velocity of droplet clusters. The time scale of the droplet clusters increased with both the turbulent Reynolds number and the Stokes number, but its dependence was stronger on the turbulence level. In addition, the effect of filling factors of turbulent flows by turbulent structures on droplet clustering was discussed, which led to suggestions of potential flow control methods to mitigate droplet preferential concentration. (c) 2019 Author(s)

慈善捐赠对业绩异质性企业价值的影响研究——来自中国上市公司的经验证据

慈善捐赠作为企业履行社会责任的重要表现形式,受到了社会的广泛关注。现有关于慈善捐赠与企业价值之间关系的研究尚未得到一致的结论,单纯考虑二者关系可能使所得结论有失偏颇,本文将企业相对业绩纳入到分析框架,重点研究了慈善捐赠对企业价值的影响在不同业绩水平下是否有所差异。本文采用2003—2015年中国沪深两市A股上市公司为研究样本,研究了慈善捐赠对业绩异质性企业价值的影响。研究发现:相对于业绩较好的企业,业绩较差企业的慈善捐赠价值效应明显更弱,这表明绩差企业的捐赠行为更多的是代理问题的体现,而非利于企业发展的战略性行为;考虑市场化进程和政策不确定性的影响,该现象主要表现在市场化程度较低的地区和政策不确定性较高的地区。本文的研究有助于更好地认识慈善捐赠的经济后果,同时也为政府监管者监督绩差企业慈善捐赠行为提供了理论依据。中央高校基本科研业务费专项资金一般项目“宽松货币政策下制造业企业房地产投资对企业业绩的影响机理研究”(项目编号:XDJK2019C006)重庆市社会科学规划项目“非金融上市公司金融化的同伴效应研究”(项目编号:2018PY61)西南大学人文社会科学校级研究项目重大项目培育“新常态下正式与非正式制度性因素对公司亏损逆转稳定性的影响研究”(项目编号:SWU1909031

发动机中的关键流体力学问题专题序

化学燃料发动机通过燃料与氧化剂燃烧,将化学能转换为工质动能,使机械结构运动或形成高速射流产生冲量而产生动力.其中,吸气式发动机利用稠密大气中的氧气,大幅降低氧化剂携带需求,具有较高的能源转换效率;增压式发动机依靠自身增压系统实现燃料和/或氧化剂增压输运,具有较强的环境适应性.针对多种天地活动需求,不同的动力循环方式有效支撑了各类运载任务,是运载系统的关键技术之一

On Relations between Distribution and Relations of Production in Capital

马克思在《资本论》中提出了分配关系是由生产资料的所有制关系决定,分配关系本质上和生产关系是统一的,是生产关系的反面,同时又是生产关系的表现的观点。生产关系和分配关系具有历史的暂时的性质。In his book Capital,Marx ever stated that the distribution relationship is determined by the ownership relation of the means of production while it is essentially uniform with the relations of production,which is the opposite of the relations of production.In the meanwhile it is also the representation of the relations of production.Both the relations of production and the distribution relationship possess the temporary natures of history

激光聚焦纹影测速技术初步研究

压力皮托管和热线风速等侵入式流场速度测量技术在超声速测量过程中会显著影响流场特征。粒子图像测速技术为非侵入流场测试技术,但需要播撒示踪粒子,而示踪粒子在大梯度流场条件下存在跟随性问题且可能影响反应流场的化学反应路径。因此,无示踪粒子的纹影测速技术在高超声速反应流动研究中应用具有较大优势和潜力。本文针对二维聚焦纹影测速技术,搭建了激光聚焦纹影光路系统,提出了使用积分球作为纹影光源的方法,提高了聚焦纹影的光源均匀性并有效降低了相干噪声;验证了通过光绘菲林技术制作刀口栅和光源栅,可满足对刀口栅和光源栅微米量级加工精度需求;最后总结推导了适用聚焦纹影的投影运动光流方程

Characteristics of clustered particle relative velocity in homogeneous and isotropic turbulence

Particle collisions are mainly governed by the preferential concentration of inertia particles and the formation of fold caustics. By fold caustics, we mean that relative velocity does not go smoothly to zero when the particle separations decrease due to inertia. Despite the importance of the second-order relative velocity structure function, there has been relatively little experimental research on the formation of caustics due to the high accuracy requirements for the particle relative velocity measurements. In the dissipation range, an obvious departure between the second-order structure function of particles normalized by the square of the Kolmogorov velocity and the Kolmogorov turbulent scaling of r(2) was observed for all four experimental conditions. In the inertial range, the second-order structure function normalized by the square of the Kolmogorov velocity was consistent with the scale form of r(2/3) in all cases. The conditional second-order relative velocity structure function of particles in clusters differs from that of the arithmetically averaged particle statistics in both the dissipation range and the inertial subrange. In the dissipation range, caustics are present for all categories of particles. In the inertial range, the scaling of the second-order velocity structure function is almost identical for all categorized particle types

Spatial correlations and relative velocities of polydisperse droplets in homogeneous isotropic turbulence

We investigate the motions of polydisperse droplets in homogeneous and isotropic turbulence at Reynolds numbers Re-lambda = 200-300. The emphasize is put on the parameter dependences of spatial velocity correlations (SVCs) and relative velocities (RVs) of droplets, which are relevant to particle transport and dispersion in turbulence and have been less studied in experiments. The Kolmogorov-scale Stokes number is St(p) = 10(-1)-10(1), and the settling parameter, i.e., the ratio of particle settling velocity to fluid velocity fluctuations, is Sv(L) = 0.5-2.0. Using high-resolution measurements, we can resolve the motions of turbulence and droplet over a wide range of scales (10(-1)eta to 10(2)eta, eta is Kolmogorov length). The parabolic behavior in droplet SVCs near the origin is observed, similar to turbulence. The droplet SVCs are smaller than turbulence for all scales and decrease with both St(p) and Sv(L). At large scales, the droplet RVs, smaller than those of turbulence due to the inertial filtering effect, also decrease with St(p) and Sv(L). At small scales, the path-history effect leads to larger droplet RVs than fluid RVs. Interestingly, we find RVs present a non-monotonic trend with St(p) and reach a valley at St(p) asymptotic to 1.0. It may originate from particle clustering and preferential sweeping effects, which both prevail at St(p) asymptotic to 1.0. It is also found that droplet motions are less intermittent than turbulence. This is in contrast to the previous observations by simulations with the gravity effect being ignored. The intermittency of droplet RVs decreases with Sv(L) due to the diminished droplet-turbulence interactions, and it presents opposite trends with St(p) for small and large scales. Finally, the balance between the effects of path histories and turbulent structures makes the velocity statistics of droplets quasi-independent from the scale in the range of the dissipative scale (r (sic) 5 eta). Published under an exclusive license by AIP Publishing

一种液体燃料雾化过程中两相测量方法及系统

本发明实施例涉及一种液体燃料雾化过程中两相测量方法及系统。一种液体燃料雾化过程中两相测量方法，所述方法包括：光源生成设备，生成光束，并传输至光源整形设备；光源整形设备，对所生成的光束进行整形，并耦合至液核；成像设备，在液态燃料二次破碎扩散相中，获取光束诱导预设类型的染料所在波段的光信号；针对光信号，采集双帧第一图像；对双帧第一图像进行互相关分析，获取速度空间分布矢量图；成像设备，在液态燃料二次破碎湍流疏运相中，针对示踪粒子，采集双帧第二图像；对双帧第二图像进行互相关分析，获取速度空间分布矢量图；其中时序同步设备，生成同步脉冲信号，用于对光源生成设备与成像设备的同步