A Research on The Personal Income Tax Incentives Policy of Public Welfare Donation

近年来，随着经济的快速发展，我国城乡居民收入和生活水平普遍提高，越来越多的家庭摆脱了贫困、实现了小康。但与此同时，也带来了贫富差距扩大、贫困弱势群体增多、地区之间发展严重失衡等一系列社会问题。目前，我国的社会保障体系尚未完善，弱势群体得不到妥善的救助，公益慈善事业在公共领域的功能开始日益受到人们的重视。 从政治经济学的角度看，社会财富的分配要经历两个环节：初次分配和再次分配。初次分配是以市场为导向的分配，注重效率；再次分配是以政府为导向的分配，注重公平，其主要手段是税收。而各国的实践发展表明，任何一个经济体制成熟的国家，社会的财富还要经历第三次分配，即公益慈善分配，这种分配是一种自愿行为。然...In recent years, with the rapid economic development of our country, the income of urban and rural residents and living standards are generally improved, more and more families are out of poverty and to achieve a well-off. But at the same time, it also brings a series of social problems, such as a widening gap between rich and poor, the increase of poor and disadvantaged groups, a serious imbalanc...学位：法律硕士院系专业：法学院法律系_法律硕士(JM)学号：1302009115035

九龙江流域地表水锰的污染来源和迁移转化机制

锰是人体必需微量元素,但近年来河流湖库等地表水锰超标现象时有发生,威胁供水安全.本文于2016—2017年在福建省九龙江流域开展水系沿程梯度调查及机理实验,结合历史监测资料综合研究,探明九龙江锰含量的时空分布与迁移转化规律,揭示九龙江锰的污染来源、超标成因与调控机制.结果表明,溶解锰高值及超标站位集中在北溪上游矿区支流和干流部分水库,且主要发生在枯水期;上游矿区支流颗粒锰含量最高,随后从上游到下游沿程递减,且与总悬浮颗粒物(TSM)和pH显著正相关(p7.8)环境促进亚热带红壤颗粒富集锰,大量富锰颗粒进入pH逐渐下降的河流下游和电站库区后向溶解锰转化,从而导致锰超标.河流下游及库区pH值下降的主要原因包括酸沉降、酸性废水排放、富营养化条件下有机物分解等.研究结果为我国地表水锰污染防控、饮用水安全保障与流域水环境综合管理提供科学依据.国家重点研发计划(No.2016YFC0502901);;福建省环保科技计划项目(No.2016R017)~

AERODYNAMIC DRAG MEASUREMENT IN A HIGH-ENTHALPY SHOCK TUNNEL

Shock tunnels create very high temperature and pressure in the nozzle plenum and flight velocities up to Mach 20 can be simulated for aerodynamic testing of chemically reacting flows. However, this application is limited due to milliseconds of its test duration (generally 500 mu s-20 ms). For the force test in the conventional hypersonic shock tunnel, because of the instantaneous flowfield and the short test time [1-4], the mechanical vibration of the model-balance-support (MBS) system occurs and cannot be damped during a shock tunnel run. The inertial forces lead to low frequency vibrations of the model and its motion cannot be addressed through digital filtering. This implies restriction on the model's size and mass as its natural frequencies are inversely proportional the length scale of the model. As to the MBS system, sometimes, the lowest natural frequency of 1 kHz is required for the test time of typically 5 ms in order to get better measurement results [2]. The higher the natural frequencies, the better the justification for the neglected acceleration compensation. However, that is very harsh conditions to design a high stiffness MBS structure, particularly a drag balance. Therefore, it is very hard to carried out the aerodynamic force test using traditional wind tunnel balances in the shock tunnel, though its test flow state with the high-enthalpy is closer to the real flight condition. Based on above issues, many balance researchers proposed several special balances to measure aerodynamic forces in the impulse facilities with high-enthalpy, that is, accelerometer balance [5-7], stress-wave force balance [8-10], free-flight measurement technique [11-16], and compensated balance [17]. Owing to the very short test time, however, the mature technology was undeveloped for the force measurements in the shock tunnel with short test duration. Based on the strain-gauge sensor's higher accuracy and sensitivity, Wang et al. [18, 19] designed a very high-stiffness pulse-type balance using the strain gauge sensor and successfully carried out a series of force tests in a large-scale shock tunnel, which has long test duration of more than 100 ms. In this study, a pulse-type strain-gauge balance (PSGB) was used for measuring the drag of a cone in a short-duration high enthalpy impulse facility, JF10. The test duration is approximately 3-7 ms. Force tests were conducted for a large-scale cone with a length of 375 mm in the JF 10 shock tunnel. The finite element method (FEM) was employed for the analysis of the vibrational characteristics of the MBS structure to ensure a sufficient number of cycles, particularly for the axial element structure, during 4 ms test duration (in the present flow conditions). The PSGB used in the test shows good performance, wherein the frequency of the MBS system increases because of its stiff construction. The test results were analyzed to see the effect of high temperature gas by comparing with the data obtained in nearly ten wind tunnels

Numerical simulation of non-equilibrium characteristics of high enthalpy shock tunnel nozzle flow

高焓激波风洞是开展高超声速流动研究的重要地面模拟设备,但其产生的高焓气流在喷管中的膨胀过程是一种典型的热化学非平衡流动,试验段特征参数通过直接实验测量难以完全确定。本文通过求解耦合双温度模型的轴对称Navier-Stokes方程,研究了高焓激波风洞中典型状态下气流的热化学非平衡流动特性,分析了焓值对非平衡特性的影响规律。结果表明,喷管出口自由流均匀区域达到出口截面直径的75%以上,能够为实验提供足够的空间;喷管出口自由流处于热化学非平衡状态,在喷管喉道后约1/5喷管长度处气流即已处于冻结流状态,组分浓度和振动温度随气流流动基本不变;焓值在8.4MJ/kg~19.5MJ/kg之间变化时,非平衡程度随着焓值的增加而增强,但是低焓值时非平衡程度的增强更加剧烈

铜箔量热计的激波管标定

铜箔量热计作为一种厚膜热电偶，在大热流测量方面有较好的应用优势。本文在铜箔量热计工作原理的基础上，对其非理想性误差进行理论分析，同时利用激波管对其进行标定。理论分析结果表明铜箔量热计在应用前须要进行标定。激波管标定结果显示单个铜箔量热计具有较好的重复性，批次传感器散差低于12%

InAs/GaAs自组织量子点激发态的激射

将覆盖层引入生长停顿的量子点结构作为激光器有源区来研究量子点激光器受激发射机制。由于强烈的能带填充效应，光致发光谱和电致发光谱中观察到对应于量子点激发态跃迁的谱峰，大激发时其强度超过基态跃迁对应的谱峰。最后激发态跃迁达到阈值条件，激射能量比结构相似但不含量子点的激光器低，表明量子点激光器中首先实现受激发射是量子点的激发态

低温GaAs外延层上生长InAs量子点的研究

利用退火技术，实现了在低温GaAs外延层上InAs量子点的生长。透射电镜(TEM)研究表明，低温GaAs外延层上生长的InAs量子点比通常生长的InAs量子点明显变小，且密度变大，认为是由于低温GaAs中的点缺陷以及As沉淀引起

生长停顿对量子点激光器的影响

在InAs自组织量子点的GaAs覆盖层中引入生长停顿，将这种量子点结构作激光器的有源区，与不引入生长停顿的量子点激光器进行对比后发