House Price, Consumption Power and Gap of Demographic Urbanization in China

This paper investigates the gap of demographic urbanization arising from the difference between rural residents who have migrated to cities and those who have acquired urban citizenship in the process of China's urbanization. The skyrocketing house prices and insufficient household consumption power are key factors to the widening gap, which had reached 18% in 2013. In order to explore this issue, by creating the basic model and the model with interaction term, this paper has analyzed the relationship among house prices, consumption power and gap of urbanization using the data of 31 provinces between 1999 and 2013 in China. Empirical result indicates that: there is a positive correlation between the house prices and the gap of China's demographic urbanization. However, such a correlation is restrained by these rural migrants who rent houses in cities. For an increase of house price by 1%, the gap of urbanization will widen by 1.05%. Although rising urban consumption power of rural residents has increased the ratio of migration, the lagged growth of consumption power has led to a widening gap of urbanization. Therefore, the only way to effectively reduce the gap of demographic urbanization is to increase the consumption power of migrant population and optimize consumption structure.

AUTOREGRESSIVE MODEL AND POWER SPECTRUM CHARATERISTICS OF CURRENT SIGNAL IN HIGH FREQUENCY GROUP PULSE MICRO-ELECTROCHEMICAL MACHINING

The identification of the inter-electrode gap size in the high frequency group pulse micro-electrochemical machining （HGPECM） is mainly discussed. The auto-regressive（AR） model of group pulse current flowing across the cathode and the anode are created under different situations with different processing parameters and inter-electrode gap size. The AR model based on the current signals indicates that the order of the AR model is obviously different relating to the different processing conditions and the inter-electrode gap size; Moreover, it is different about the stability of the dynamic system, i.e. the white noise response of the Green＇s function of the dynamic system is diverse. In addition, power spectrum method is used in the analysis of the dynamic time series about the current signals with different inter-electrode gap size, the results show that there exists a strongest power spectrum peak, characteristic power spectrum（CPS）, to the current signals related to the different inter-electrode gap size in the range of 0～5 kHz. Therefore, the CPS of current signals can implement the identification of the inter-electrode gap.

Robust Optimization Operation of Power System Considering the Non-probabilistic Uncertainty of Parameter

Probabilistic method requires a lot of sample information to describe the probability distributions of uncertain variables and has difficulty in dealing with the optimization problem with uncertain parameters which contains unsufficient information.To solve this problem,a robust optimization operation method based on information gap decision theory(IGDT) is presented considering the non-probabilistic uncertainties of parameters.By the proposed method the maximum resistance to the disturbance of uncertain parameters is achieved and the optimization strategies with uncertain parameters are presented.Finally,numerical simulation is performed on the modified IEEE-14 bus system.Numerical results show the effectiveness of the proposed approach.

Experimental Study of Reversely Switched Dynistor Discharge Based on Gap Breakdown Load

Breakdown characteristics of a gap breakdown load was investigated in this paper, and a reversely switched dynistor （RSD） discharge circuit was designed based on the load. Based on the characteristics of the load, the RSD discharge circuit was improved and optimized. The volume of the magnetic switch was reduced. To protect the thyristor and RSD, a diode was anti- parallely connected with the thyristor, which reduced the time requirement when a power voltage was applied to RSD. Experimental results show the circuit designed in this paper can switch a high voltage and high current smoothly, and allows the power voltage to change in a wider range.

Power Semiconductor Devices-an Enabling Technology for Future High Efficient and High Power Density Power Conversion Systems

Power semiconductor devices are the key technology driver for all power electronic system engineering.The main development trend for power devices is going towards higher power handling capability at even smaller Sivolume, faster switching performance,advanced ruggedness and reliability at elevated operating temperature and extended SOA diagrams.To cover all applications in the various fields of industry,consumer,computing and automotive the device optimization is different for low voltage power MOSFET,for high voltage MOSFET,for plasma modulated devices and components based on wide bandgap(WB) material.In the paper,the main development trends will be described and discussed.

Exploring the Gap:the Influence of Chair-CEO Age Dissimilarity on CEO Monitoring and Incentives

This paper investigates how the chair-CEO age dissimilarity and CEO power affect the dispersion and change of chair-CEO pay gap from both static and dynamic perspectives.The substantial age dissimilarity between the chairman and the CEO gives rise to cognitive conflict,thereby increasing board monitoring for firms with greater monitoring needs.Using data of China s listed firms from 2009 to 2017,we find a significant negative effect of CEO power on pay gap between the chairman and the CEO.In addition,when CEO is a member of the board or compensation committee,the power of CEO has different influences on the compensation,but the cognitive conflicts caused by chair-CEO age dissimilarity always inhibit the CEO s power.Thus,age dissimilarity has become an important complement to the board s regulatory mechanisms.

Analysis of Light Load Efficiency Characteristics of a Dual Active Bridge Converter Using Wide Band-Gap Devices

In this paper, the zero voltage switching (ZVS) region of a dual active bridge (DAB) converter with wide band-gap (WBG) power semiconductor device is analyzed. The ZVS region of a DAB converter varies depending on output power and voltage ratio. The DAB converters operate with hard switching at light loads, it is difficult to achieve high efficiency. Fortunately, WBG power semiconductor devices have excellent hard switching characteristics and can increase efficiency compared to silicon (Si) devices. In particular, WBG devices can achieve ZVS at low load currents due to their low parasitic output capacitance (Co,tr) characteristics. Therefore, in this paper, the ZVS operating resion is analyzed based on the characteristics of Si, silicon carbide (SiC) and gallium nitride (GaN). Power semiconductor devices. WBG devices with low Co,tr operate at ZVS at lower load currents compared to Si devices. To verify this, experiments are conducted and the results are analyzed using a 3 kW DAB converter. For Si devices, ZVS is achieved above 1.4 kW. For WBG devices, ZVS is achieved at 700 W. Due to the ZVS conditions depending on the switching device, the DAB converter using Si devices achieves a power conversion efficiency of 91% at 1.1 kW output. On the other hand, in the case of WBG devices, power conversion efficiency of more than 98% is achieved under 11 kW conditions. In conclusion, it is confirmed that the WBG device operates in ZVS at a lower load compared to the Si device, which is advantageous in increasing light load efficiency.

低抖动大气压空气电晕均压多间隙气体火花开关

为了发展结构简单、便于维护的大功率气体火花开关,研制了大气压空气电晕均压多间隙气体火花开关,该开关采用电晕放电均压方式,由9个相同的间隙构成。利用有限元分析方法对9间隙电晕均压气体火花开关的电场进行了分析,发现适合长度的电晕针对开关主间隙的电场影响很小,且加载触发脉冲时可在中间间隙形成了强烈的畸变电场。在理论分析的基础上,开展了开关击穿特性研究,实验结果表明电晕均压有利于提升开关的稳定性,开关自击穿电压分散性降低,自击穿电压略微增大;同时多间隙开关实现了良好的触发导通,在工作电压60~85 kV(工作欠压比56.8%~80%)范围内,开关的击穿延时抖动均小于20 ns,当工作电压达到80 kV以上时,抖动可小于10 ns。文中设计的大气压空气电晕均压多间隙气体火花开关可用于直线脉冲变压器等脉冲功率系统,使用的基于电场模拟对电极结构进行优化的方法对设计其他类型的开关具有借鉴意义。

太赫兹间隙波导径向功率合成技术研究

针对太赫兹固态功放研制对于低损耗功率合成器的需求,基于间隙波导技术在200~240 GHz的频段开发了一种4路波导径向功率合成器。经无源测试,该间隙波导径向合成器的回波损耗优于-15 dB,无源合成效率达到了88.7%,展现出了间隙波导在太赫兹频段的低损耗特性。通过封装2只GaN功放芯片形成功率模块为基本单元,进一步开展有源功率合成,最终在220 GHz实现了311 mW的峰值输出功率,在200~240 GHz的频率范围内平均功率合成效率为81%。

基于租差理论的城市生态空间演变动力分析与规划对策——以佛山市南海区为例

改革开放以来,珠三角地区在活跃的村镇工业化推动下实现了经济与产业的快速发展,但也带来趋向破碎化的城市生态空间。引入租差理论,以利益驱动为分析基础,从政府管控、经济发展、自然环境3方面,构建“政府力—市场力—自然力”的城市生态空间演变动力分析模型,以广东省佛山市南海区为例进行分析。得出结论:(1)2010—2020年间佛山市南海区生态空间演变中,政府力是城市生态空间演变的主要动力;(2)生态用地租金普遍较低,市场力对城市生态空间的影响尚不充分,仅通过土地租金推动生态空间实施难度较大。最后提出规划对策建议:一是建立兼顾生态效益与经济成本的生态空间网络;二是建立以降低其他用途与生态用途的租差为导向的保护与修复配套政策,引导低效建设用地通过生态修复、拆旧复绿向生态空间转化。

俄制核电末级叶片围带磨损原因分析及间隙修复

采用试验手段和有限元方法对某核电汽轮机末级叶片围带磨损原因进行了分析,并基于叶片围带在不同间隙下的安全性和经济性分析,确定了叶片安全运行时的围带间隙范围,给出了叶片围带间隙的修复方法和实施工艺流程,为后续末级叶片检修提供了重要的理论依据。

党组织嵌入公司治理对高管—员工薪酬差距的影响研究

收入分配制度的合理性是保障社会公平与正义的关键。然而,随着高管薪酬对企业绩效的作用逐渐凸显,高管薪酬不断提高致使高管“天价薪酬”成为普遍现象,引起理论界和实务界的广泛关注。基于我国特殊的公司治理制度,以2010-2021年我国沪深A股上市公司为研究样本对党组织嵌入公司治理是否影响以及如何影响高管—员工薪酬差距进行研究,发现党组织融嵌公司治理有助于抑制高管—员工薪酬差距,而且党组织融嵌程度越高,对高管—员工薪酬差距的抑制作用越强;此外,这种抑制作用对国有企业、董事长或总经理无政治关联、市场化程度低的企业更显著;进一步分析发现,党组织嵌入公司治理可以通过抑制管理层权力的扩大和降低企业风险进而抑制高管—员工薪酬差距。从中国特色的党组织嵌入公司治理视角探讨高管—员工薪酬差距的影响因素以及作用机制,对于丰富薪酬差距影响因素研究和党组织嵌入公司治理效应研究方面的文献,加强党组织建设、全面促进党组织建设与公司治理结构的有机结合、优化收入分配制度改革具有借鉴意义。

基于信息差距决策理论的虚拟电厂报价策略

为进一步提升分布式能源的调节潜力,基于信息差距决策理论,将探讨虚拟电厂(virtual power plant,VPP)在参与需求响应(demand response,DR)策略时的竞价方式分为平衡型、保守型和进取型3种策略模型,并为每种策略设计鲁棒函数和机会函数,分别实现对不同类型决策的优化。同时,设置ε约束模型,考虑了碳排放和利润的权衡关系。采用IEEE 18节点系统作为仿真环境,验证了所提方法的优点和必要性。仿真结果表明,保守型VPP能够保证在未来价格落入最大鲁棒性区间时获得最小关键利润;进取型VPP能够从意外的价格波动中获益,并实现期望的利润。

气体火花间隙开关通道电阻及热效应特性研究

针对一种应用于高功率重复频率Marx型脉冲功率源的两电极火花间隙气体开关,开展了火花通道电阻及其热效应特性研究,分析了火花间隙通道电阻热效应的影响因素,研究了重复频率连续工作条件下开关腔体内温度及气压变化。研究结果表明,开关腔体内气压和温度随着工作时间增长呈现先快速增加然后缓慢增长趋于稳定的趋势,脉冲电流幅值的增长对热量沉积的增加效果非常明显。研制的两电极火花间隙开关,在导通峰值电流14.7 kA、脉冲宽度160 ns的条件下连续运行9000个脉冲时,开关通道产生热量约36.6 kJ,在电流导通时间内,通过焦耳热效应计算得到开关导通时间内火花通道电阻平均值约0.12Ω。

数字化转型对企业收入分配的影响研究

采用沪深A股上市公司2011—2021年数据的分析表明:数字化转型对企业的总收入、劳动收入份额、管理层与普通员工薪酬差距均具有显著的正向影响,同时显著提高了企业的技术创新水平、高技能和高学历员工占比、风险承担水平,并缓解了企业的融资约束,表明数字化转型具有产出增长效应、结构优化效应和风险加剧效应,从而可以对企业的收入分配产生增加收入、提高劳动收入份额、拉大内部薪酬差距等多维度影响。此外,管理层权力增强会强化数字化转型对薪酬差距的拉大作用。异质性分析发现,数字化转型对企业收入和薪酬差距的影响在国有企业中更为显著,对劳动收入份额的影响在非国有企业中更强,对科技型企业收入分配的影响比非科技型企业更强。分位数回归显示,数字化转型要在达到一定程度后才能显著促进企业收入增长,随着数字化转型程度的提高,数字化转型对企业劳动收入份额的提升作用趋于增强,而对企业内部薪酬差距的拉大作用趋于减弱。因此,应在积极推进企业数字化转型的同时合理约束管理层权力,利用数字化做大“蛋糕”并分好“蛋糕”。

考虑碳捕集与光热电站的综合能源系统优化调度

为高效处理综合能源系统IES(integrated energy system)中因热电供需矛盾导致的弃风及碳排放问题,构建了考虑碳捕集与封存CCS(carbon capture and storage)技术以及光热CSP(concentrating solar power)电站的优化调度模型。首先,利用CCS技术对热电联产CHP(combined heat and power)机组进行低碳化改造,建立碳捕集热电联产机组的数学模型;然后,在此基础上引入CSP电站,构成CSP-CHP-CCS协同框架,并建立含CSP-CHPCCS的IES低碳经济调度模型;接着,针对系统中的源、荷不确定性,采用信息间隙决策理论进行模拟分析,构建风险规避鲁棒模型;最后,通过算例仿真对比,验证了所提模型在促进新能源消纳和降低碳排放方面的有效性。

狭小间隙下液力变矩器搅油功率损失模型

针对液力变矩器高速旋转产生较大搅油功率损失问题,以某液力变矩器为研究对象,基于CFD数值模拟及数据统计分析方法,提出一种搅油功率损失预测模型.该模型主要考虑液力变矩器装配间隙几何特征、运行参数、润滑油物性与润滑状态等因素影响,采用正交分解法选择25组不同运行参数下的搅油过程进行数值模拟,并结合某传动装置实际运行工况和使用要求进行了多工况验证.结果表明:随着润滑油雷诺数增大,搅油功率损失成指数型快速增长;搅油功率损失随径向间隙的增大而减小,随轴向间隙的增大而增大;当径向间隙小于9 mm时,搅油损失功率随着径向间隙减小而急剧增大;相比于轴向间隙,径向间隙对搅油功率损失值的影响程度更大;狭小间隙下液力变矩器搅油功率损失模型结果与数值计算结果总体符合较好,相对误差在10%内.研究结果可为狭小间隙液力变矩器设计及综合传动装置的优化提供一定技术支撑.

基于信息间隙决策理论的含碳捕集−电转气综合能源系统优化调度

【目的】为科学统筹综合能源系统运行经济性、稳定性和低碳性优化目标,采用何种技术手段以提升能源转化效率,减少系统能源浪费和区域环境污染,是当下综合能源系统合理优化的主要问题。为此,提出一种基于场景生成与信息间隙决策理论的含碳捕集与封存(carbon capture and storage,CCS)—两段式电转气(power to gas,P2G)综合能源系统低碳优化策略。【方法】在技术层面,通过对电P2G两阶段精细化建模,提高氢能利用效率,建立热电联产(combined heating and power,CHP)-CCS-P2G耦合模型;在市场机制层面,引入阶梯型碳交易模型以降低系统中CO_(2)排放量。最终,基于信息间隙决策理论(IGDT)构建不同风险偏好下的优化调度模型。【结果】以典型综合能源系统进行算例分析,仿真结果表明所提模型可提高风光消纳率,实现系统低碳、经济、稳定运行。【结论】该优化策略可有效帮助决策者根据其风险偏好制定风险规避与风险追求策略下的调度方案,实现系统不确定性与经济性的平衡。

风电机组塔筒法兰间隙填充修复技术研究及应用

塔筒是风电机组的重要支撑构件,其服役状态对风电机组的安全可靠运行意义重大。通过试验方式探讨法兰间隙对风电塔筒局部力学结构-塔筒法兰、母材钢板本体的潜在影响。使用钢制垫片填充的方式,减小塔筒间隙对塔筒受力性能的影响,并验证其效果。现场采用钢制垫片填充的方式对法兰间隙进行填充修复。在间隙修复前后,使用应力检测手段对塔筒的应力状态进行检测。通过对比修复前后的应力状态变化,定量分析法兰间隙对塔筒本体的影响。在进行钢制垫片填充后,法兰间隙得到了有效修复。通过应力检测,发现修复后的塔筒应力状态明显改善,受力不均现象得到显著缓解。定量分析显示,填充修复后,塔筒的受力性能得到了显著提高。兰间隙的存在确实会对塔筒的受力性能产生不良影响,但通过钢制垫片填充的方式可以有效修复间隙,并改善塔筒的受力状态。采用钢制垫片填充的方法可以显著改善塔筒受力不均的现象,从而提高风电机组的安全性和稳定性。

表面微放电等离子体特性参数计算及介质片性质的影响

表面微放电(SMD)在不同的领域有着越来越广泛的应用。为了深入理解其放电特性及介质片性质的影响,基于放电物理过程及SMD特有的放电结构,建立了等效电路模型,并联立Boltzmann方程求解器求解电子连续性方程,得到气隙电压、等离子体电阻及电子密度等特性参数。结果表明,对于同一种类不同厚度的介质片,功率相同时的放电面积及各特性参数一致,对于不同种类的介质片,介电常数较大的介质片下SMD的放电功率、气隙电压、等离子体电阻及电子密度随外加电压的变化率较大。在电压相似的情况下,相同厚度下介电常数较大的介质片放电功率及气隙电压更大,等离子体电阻更小。最后通过比较计算功率和测量功率,验证了模型及仿真计算的正确性。