企业竞争力的性质:一个要素异质性的视角

企业价值不同于企业要素的价值,企业是一种与市场不同的资源配置方式,仅仅从所有者权益来理解企业的价值是不全面的。企业是要素的组合,要素的不同组合将产生一种区别于要素市场价格的组织资本,企业中这种组织资本的存量状况决定了企业的价值和企业的竞争力

Is House Purchase Limit an Effective Policy to Control Housing Price？

2010年以来我国政府实施的五次房地产宏观调控中，以数量管制性质的“限购令”最为严苛。本文按照户籍和限购地域两个标准对限购政策了进行细分，在倍差法的研究框架内，通过动态面板模型GMM估计来评估限购政策对抑制住宅价格上涨的效果。实证研究发现，对非户籍购房人实施限购的政策效果最为明显。限购范围影响政策效果，仅在市区范围内限购难以起到抑制房价上涨的作用。通过对限购政策效果的评估，本文认为，投资（投机）性需求是推动我国房价上升的主要动力，我国房地产泡沫的根源在于粗放的经济增长方式，以货币超发带动经济增长的发展模式是房地产泡沫的根源所在，也是我国房地产市场调控的难度所在。【英文摘要】As a quantity administration policy, will the House Purchase Limit influ- ence the increasingly high house price？ We firstly classify the limit by household regis- tered and the area restricted to buy, and then use GMM estimation of a dynamic panel data model to analyze the effects of the policy on the high-rising house price under the framework of difference in differences. The findings are as follows. The most obvious effect is on people with no household registered. The area restriction also has influence on the house price and it is difficult to reduce the high-rising house price provided that the restriction is carried out only in the main business area of the city. We have dis- covered that the investment （speculation） demand is the essential factor influencing housing price. In order to solve the problem of bubbles in the house market, we suppose to deal with the problems beyond the house market. It is difficult to control the house market without reducing the excess liquidity which is the main motivation of the economic growth since the reform period.教育部人文社会科学研究规划基金项目（12yja790185）；国家社会科学基金项目（1icjl063）的资

我国省际收入差异的成因:要素积累还是生产率

本文借鉴增长核算方法估算了1987-2004年我国各省区的全要素生产率,并对各省区的劳均GDP进行了水平分解和不同形式的方差分解。研究结果显示,虽然物质资本和人力资本等投入要素的积累差异是导致我国各省区经济发展差距的主要原因,但是,全要素生产率在省际之间的巨大差异是造成我国各省区经济发展差距的更为重要原因

Unmanned aerial vehicles swarm conflict based on multi-agent system

本文将多agent系统引入到大规模无人机集群对抗决策系统中,给出了基于多agent系统的大规模无人机集群对抗决策方法.将机群中的每个无人机视为一个独立agent,建立了无人机运动模型,为无人机设计了独立的个体行为集,并针对每种行为给出了决策方法.通过每个个体无人机对其邻域环境的作用,涌现出宏观的集群对抗(作战)效果.使用MATLAB仿真软件对所设计的大规模无人机集群对抗方法进行了仿真,验证了所设计的基于多agent系统的大规模无人机集群对抗决策方法的有效性.The multi-agent system theory is employed to build the maneuvering decision-making model for large-scale unmanned aerial vehicle(UAV) swarm conflict. In this model, each UAV in the swarm is regarded as one independent agent. With the establishment of UAV motion equation, individual behavior set and action criterion, each UAV keeps on interacting with its neighboring environment and the UAV swarm conflict outcome emerges eventually from such a process. Simulation experiments are conducted using MATLAB and the results demonstrate the effectiveness of the built decision-making model for UAV swarm conflict.航空科学基金项目(20140168001)资助~

台湾海峡及厦门湾台风浪场数值模拟

本文利用国际上先进的第三代海浪模式SWAn,在充分考虑风能量输入、白浪效应、水深诱导的波浪破碎、底摩擦、波-波间的非线性相互作用等物理过程。以0604号台风“碧利斯“为例,通过嵌套计算方式,模拟了台湾海峡及厦门湾台风浪场的分布特征。将数值模拟结果与浮标测站实测资料对比分析,结果表明台风浪高模拟值与实际台风资料相符较好,可以为该海域台风浪的模拟提供较好的参考

Optimal Design of Control Tension in Winding Process for Large Wound Roll

提出了一种适合高品质、大卷装收卷的控制张力设计方法。首先,介绍了收卷机张力控制的主要结构及其工作原理。再根据弹性力学原理,分析了收卷张力与卷装内应力分布的关系模型。在此基础上,讨论了恒张力收卷、锥度收卷和恒力矩收卷模型,并计算了其卷装的内应力分布情况。最后,提出了一种应用单纯形法进行最优收卷张力求取的方法。实验结果表明所提设计方法能有效保证所收卷的大卷装具有均匀的内张力分布。A new design method to tension control in winding process is developed for producing high-quality large wound roll.Firstly,the work theory and equipment construction of tension control system in a winding machine are introduced.Secondly,the relationships between winding tension in the winding section and internal stress distribution within wound roll are analyzed based on the elasticity mechanics theory.Thirdly,the cases of constant tension,taper tension and constant torque winding are discussed,and the distributions of internal stress in the wound rolls are calculated.Finally,an application of simplex method to searching for the optimal winding tension is presented.The experimental results show that the proposed design method can ensure the internal tensions in a large wound roll to get uniform distribution.中央高项基本科研业务费资助项目(2010121041

空气环境下退火温度对连续SiC自由膜结构与发光特性的影响

采用熔融纺膜与先驱体转化法相结合制备出连续SiC自由薄膜,研究薄膜在1300,1400,1500℃温度下空气退火处理的氧化行为,以及退火温度对薄膜微观结构、光致发光特性(PL)、硬度和电阻率的影响。结果表明,SiC薄膜在1300℃具有较佳的抗氧化和发光特性,随着退火温度的升高,薄膜的抗氧化和发光特性略有降低,薄膜中无定型SiOxCy减少,-βSiC晶粒长大及游离碳增多,薄膜表面硬度与电阻率下降,表面惰性致密氧化层的生成保护阻挡氧扩散,从而有效减缓薄膜进一步被氧化

Selective Catalytic Hydrogenation of Cinnamaldehyde to Hydrocinnamaldehyde

采用煤质活性炭作载体,分别用HNO3、H2O2和(NH4)2S2O8进行预处理,然后用浸渍法负载PdCl2,在H2流中还原得到Pd/C催化剂,用于肉桂醛(CAL)选择加氢制氢化肉桂醛(HCAL)的反应。考查了Pd负载量,反应温度和压力对加氢反应的影响,优化了反应条件。进一步考查了助剂Fe、Co、Ni[1]对反应的影响。最终,CAL转化率为98%,HCAL选择性为88%。Coal-based activated carbon was pretreated with HNO_3,H_2O_2 and(NH_4)_2S_2O_8 before selected as support.A series of Pd/C catalysts were prepared by means of impregnation and with PdCl_2 as precursor.It was reduced in H_2 stream,and applied to selective hydrogenation of cinnamaldehyde to hydrocinnamaldehyde.Effects of Pd-loading,reaction temperature and pressure were discussed.In addition,promoters of Fe,Co,Ni were introduced to the catalysts.At last proper conditions for the reaction were found,and 88% selectivity to HCAL at 98% conversion of CAL was obtained.国家自然科学基金(No.20203014

Advance in Red-emitting Mn⁴⁺-activated Oxyfluoride Phosphors

稳定可靠的高光子能量发光(620~650 nm)红光荧光粉, 对于构建低色温、高显指荧光粉转换型白光发光二极管(WLED)至关重要。Mn⁴⁺激活红光荧光粉是当前 WLED 用荧光粉研究热点之一。本文介绍了 Mn⁴⁺离子的能级跃迁与光致发光特性, 详细叙述了目前所报道的七种 Mn⁴⁺激活含 d⁰/d¹⁰/s⁰离子氧氟化物系列红色荧光粉(如Na₂WO₂F₄:Mn⁴⁺等)的制备方法、晶体结构及其发光特性。目前⁴⁺在氧氟化物结构中得到强 R 线(零声子线)发光的情况少, 微观配位体仍是[MnF₆]或[MnO₆], 其化学稳定性和量子效率研究也很缺乏。最后对 Mn⁴⁺激活氧氟化物红光荧光粉的研究进行了展望。The stable and reliable red phosphor with high-photon energy emission (620–650 nm) is critical for the fabrication of the phosphor-converted white light-emitting diode (WLED) with low correlated color temperature and high color rendering index. Mn⁴⁺-activated phosphor is an emerging kind of red-emitting phosphor for WLED. Herein, the energy levels transition and photoluminescence characteristics of the Mn⁴⁺ ion were introduced; then, the preparation, crystal structure and luminescent properties of as-far reported seven kinds of Mn⁴⁺-doped oxyfluoride red phosphors (such as Na₂WO₂F₄:Mn⁴⁺) containing d⁰/d¹⁰ or s⁰ cations were reviewed. Currently, only in quite rare case of oxyfluoride, Mn⁴⁺ was found to exhibit strong R-line emission, with local coordination remaining as either [MnF₆] or [MnO₆]. The studies on the chemical stability and quantum efficiency of Mn⁴⁺ -doped oxyfluoride phosphors are still insufficient. Finally, we prospected the future development of Mn⁴⁺-doped oxyfluoride phosphor

加强新时代教育科学研究工作（笔谈）

2019年11月,教育部印发《教育部关于加强新时代教育科学研究工作的意见》(以下简称《意见》),这是新中国成立以来教育部印发的首个教育科研规范性文件,对做好新时代教育科研工作具有重大开创性意义。《意见》是指导新时代教育科学研究工作的纲领性文件,在进一步明确了新时代教育科研工作的指导思想、目标任务和思路举措的同时,还为做好新时代教育科研工作提供了强大的政策支持和制度保障。为进一步学习好《意见》精神,推动建设具有中国特色、世界水平的教育科学理论体系,不断提升教育科研质量和服务水平,《中国高教研究》编辑部与厦门大学高等教育发展研究中心邀请高等教育研究领域的六位专家学者,从不同角度为新时代加强高等教育科学研究工作贡献智慧