一种基于SIR结构的三通带带通滤波器

应用双指耦合结构和枝节加载谐振器（Stub-loaded Resonator，SLR）实现了一款基于阶梯阻抗谐振器（Stepped Impedance Resonator，SIR）的滤波器。该滤波器具有3个通带，带外抑制较好，工作频段提高。通过调整阻抗比可调节第二、三通带的谐振频率；SLR结构能够增加通带数量；SLR结构和双指耦合结构均能改善滤波器的S参数。HFSS软件仿真表明，3个通带的中心频率分别为3.5 GHz、6.6 GHz、9.2 GHz，对应的分数带宽分别为5.7%、3%、2%，S11分别为-18 dB、-22 dB、-24 dB，通带内的S21分别为-1.8 dB、-1 dB、-1 dB。电路的测量结果与仿真结果较为吻合。该滤波器在5G通信的低频段具有应用前景。     

A quantitative study of financing efficiency of low‐carbon companies: A three‐stage data envelopment analysis

This study set out to evaluate the financing efficiency of low‐carbon companies. Applying a three‐stage data envelopment analysis with the data from 85 listed companies in China's low‐carbon industries over the period 2011 to 2017, this study has found that the overall financing efficiency of low‐carbon companies was relatively high, and the pure technical efficiency was quite steady over the period. The overall financing efficiency of these low‐carbon companies on average tended to change with the scale efficiency. This study has also shown that the scale efficiency was the main constraint influencing the financing efficiency of low‐carbon companies in China over the period. Our results are robust and have significant implications for policy makers and corporate managers.     

内外融资条件、融资约束与企业绩效——来自京津冀地区企业调查的新证据*

基于独特的京津冀地区企业调查数据和克服内生性的结构方程模型，本文对融资约束的成因及影响进行了实证分析。分析结果表明，企业自身条件和外部市场环境均对融资约束有重要影响，且企业自身条件对融资约束的影响更强。总的融资约束指标对企业绩效的影响不显著。在区分融资约束的不同维度后，本文发现，融资可得性提高显著促进了企业绩效提升，融资频率增加却降低了企业绩效，而融资获得速度（等待时间）对企业绩效没有统计上的显著影响。进一步的分析表明，无论是正规融资渠道，还是非正规融资渠道，上述结论仍然成立。利用多种政策提高企业的管理水平，改善企业的自身条件，是缓解融资约束的最有效办法。     

Modelling tourist flow association for tourism demand forecasting

The purpose of this study is to examine tourism demand for Singapore from 1995 to 2013 by six major origin countries which belong to three different regions. Unlike prior tourism research, we take into account the dependence relations among the different tourist flows via copula. Copula is a statistical model of dependence and measurement of association. Specifically, we investigate the association between two tourist flows in each region. Based on empirical copula estimation, the Frank function has been identified as the most appropriate to capture the pairwise dependence structures of tourist flows. The copula-based approach combined with econometric models is proposed for tourism demand analysis that can be used to predict tourist arrivals. We apply the copula-ARDL and copula-ECM frameworks to generate joint forecasts of tourist arrivals from three regions. The findings show that the forecast performance of the Frank copula-based model outperforms the benchmark model which corresponds to the independence structure (no association) of tourist flows.     

Institutional Economics as Theory of Policy Change: Impact of Past Policy Failures on Present Policy

Social scientists have developed several theories for understanding or evaluating policy change over time. Since all costs or benefits are not internalized owing to positive transaction costs, policymaking is always implemented under cost underestimation conditions and, therefore, is imperfect. I call this trait policy failure in this article. Furthermore, I show that a new framework combining the social costs approach and the legal/economic approach in institutional economics is suitable and can be applied to evaluating how past policy failures affect present policy, providing as an example the Fukushima nuclear disaster in Japan.     

基于PPP模式工程项目融资风险管理的思考

近年来,我国的经济发展较为迅猛,呈现出繁荣的景象。在此基础上,推动项目融资风险管理的出现与成长,而PPP模式较为突出,不同于暗含经济风险的传统型风险管理,能够在一定程度上助力政府财政支出压力的降低。但是需要多加关注的是,PPP模式的工程项目融资本身就具备一定的风险因素。为此,论文着眼于实际情况,充分考虑其基本特点,提出行之有效的防患策略,为我国顺利推进PPP模式工程项目管理工作提供一定的借鉴意义。     

The impact of investor structure on stock price crash sensitivity: Evidence from China's stock market

Stock price crash sensitivity refers to the conditional probability of a stock crash when the market collapses. It focuses on individual stocks' sensitivity to the market crash and can affect stock pricing significantly. Although the crash sensitivity of China's stock market is very high as a whole (Weigert, 2016), different individual stocks show varying degrees of crash sensitivity. This paper, adopting the perspective of institutional investors, explores the reasons for the difference in crash sensitivity in China's stock market, and finds that: First, institutional investors' shareholdings is positively related to firms' stock price crash sensitivity. However, after dividing institutional investors into professional (represented by financial institutions) and non-professional institutional investors (represented by general legal persons), we find that only professional institutional investors' shareholdings is negatively related to firms' stock price crash sensitivity. Second, the impact of professional institutional investors on the crash sensitivity is influenced by stock liquidity and media sentiment: when the stock liquidity of listed companies is good or the media sentiment is strong, the negative impact of professional institutional investors on the crash sensitivity is accordingly high. This paper, by highlighting the investor structure, attempts a pioneering exploration of the influencing factors of the difference in stock price crash sensitivity in China. Our empirical results enrich research on stock price crash sensitivity and the heterogeneity of institutional investors. They can also serve to guide regulatory authorities' development of institutional investors and efforts to maintain market stability.     

Financial crises,debt overhang,and firm growth in transition economies

ABSTRACT

We examine the effects of the global financial crisis of 2008 and the European debt crisis of 2011 on the relationship between capital structure, investments, and performance for Eastern European companies. While the existing literature documents how firms’ investments are sensitive to the availability of internal funds and to debt holdings, we further investigate whether this investment sensitivity also translates in different levels of performance, and document that capital structure indeed has both a direct and an indirect effect, mediated by the capital expenditure channel. We show that firms with higher financial flexibility experience higher investments and returns on capital. Over-levered firms instead suffer from a debt overhang condition, forcing them to curb investments, and consequently experiencing lower performance. Overall, we provide evidence on the importance of capital structure and financial flexibility on investments and performance, showing the real consequences of the debt overhang condition on firm value creation. Firms should therefore aim at maintaining adequate financial flexibility in order to be able to pursue future profitable investment opportunities, and avoid the under-investment problem arising from a debt overhang situation.     

Maximizing political vote in multiple districts

This paper models a resource allocation problem in the political context. Voters and political candidates of two parties are positioned in each of n given electoral districts. We assume that each voter will vote for the candidate he is more attracted to. This attraction is modeled by an attraction function. Each of the parties now attempts to allocate a finite budget to maximize their objective, which is either the popular vote or the number of districts, in which the party has a majority. Individual scenarios are examined with respect to leader-follower solutions and Nash equilibria. The paper then describes a dynamic model that successively allocates existing funds plus additional donations to candidates in different electoral districts.     

将“合伙人制”融入“合作制”的一项尝试——基于MGL合作社的案例解读与探讨

当前,合作社异化已成为阻碍合作社进一步发展的痛点,其中"合作制"下社员剩余索取权和控制权的丧失是矛盾核心,因而探求其改进方式对合作社长远发展、实现乡村振兴有重要意义。本文基于效率与公平衡量维度,通过对MGL合作社这一典型案例进行剖析发现,有效的合作社在治理结构和利益分配上具备"合伙人制"特征,并且基本契合不完全契约理论有关能够有效解决契约双方信息不对称以及剩余索取权、控制权被少数社员占有的论述。对此,应充分重视合伙人制在合作社发展中的内在有效性,弱化其是否具有规范的外在形式。