Financial Flexibility,Product Market Competition and Capital Structure

以2001-2014年中国A股上市公司为样本,将财务灵活性价值和产品市场竞争状况纳入资本结构的分析框架进行研究。结果表明:在其他条件不变的情况下,财务灵活性价值越高,公司的财务杠杆越小;除了掠夺风险与市场杠杆之间的关系不显著之外,产品市场竞争与财务杠杆正相关;由于受到严格的监管,公司在中国资本市场上的股权融资难以实现,产品市场竞争所引致的融资需求会减弱财务灵活性价值对资本结构的负向作用。This paper uses the A shares of listed companies for the period 2001-2014 to estimate and compare the value of financial flexibility. We use three different measures of product market competition:predation risk, HHI and the number of listed companies,then we analyzes the effect of financial flexibility and product market competition on capital structure of Chinese listed companies. The conclusions show that, ceteris paribus, the capital structure negatively related to the value of financial flexibility. Subjected to the supervision of CSRC, except for predation risk shows no significant effect on market leverage,other results show that the leverage of listed companies increase with the strength of product market competition;the effect of the value of financial flexibility on the capital structure is weakened by product market competition.国家自然科学基金项目(71472160);; 教育部人文社会科学规划项目(20120121110041

基于8-羟基喹啉衍生物的重金属离子荧光增强型传感的研究进展

8-羟基喹啉是重要的金属离子鳌合剂,因金属离子与其结合后可阻断其分子内激发态质子转移(ESIPT)导致荧光增强而被广泛应用于荧光传感分子的设计中.但8-羟基喹啉对金属离子的选择性较差,研究多对喹啉母环结构修饰引入辅助配位基团以改善金属离子选择性,但以8-位羟基修饰的尝试偏少.本文以8-羟基喹啉不同结构修饰的衍生物为依据,评述其在重金属离子荧光增强型传感中的应用

一种叶片裂纹检测的稀疏共振解调算法

针对强相干噪声干扰下叶片振动信号中裂纹故障微弱特征的提取问题,提出了一种基于稀疏共振解调的诊断方法。首先,利用从中心集化多分辨分析处理机组上取得的原始振动信号进行子空间重构;其次,对小波子空间信号进行希尔伯特包络解调,选取故障特征频率及其倍频成分能量占优的子空间;再次,根据周期性故障稀疏模型,采用梳形滤波器分离故障特征频率及其倍频成分,构造故障分量参考信号;最后,结合故障参考信号对子空间重构信号进行小波降噪,从而提取与叶片裂纹相关的微弱特征。在出现叶片裂纹故障的发电机组增压风机故障诊断案例分析中,仅采用多尺度分解无法在时域上得到周期性冲击故障特征。而采用所提出的基于稀疏共振解调方法进行信号处理后,强相干噪声得到了有效抑制,从而突出了故障特征。国家自然科学基金（51805398）陕西省自然科学基础研究计划（2018JQ5106）北京卫星环境工程研究所2019年度CAST-BISEE创新基金（CAST-BISEE2019-043

一种叶片裂纹检测的稀疏共振解调算法

针对强相干噪声干扰下叶片振动信号中裂纹故障微弱特征的提取问题，提出了一种基于稀疏共振解调的诊断方法。首先，利用中心集化多分辨分析处理机组上取得的原始振动信号进行子空间重构；其次,对小波子空间信号进行希尔伯特包络解调，选取故障特征频率及其倍频成分能量占优的子空间；再次,根据周期性故障稀疏模型，采用梳形滤波器分离故障特征频率及其倍频成分构造故障分量参考信号；最后,结合故障参考信号对子空间重构信号进行小波降噪,从而提取叶片裂纹相关的微弱特征。在出现叶片裂纹故障的发电机组增压风机故障诊断案例分析中，仅采用多尺度分解无法在时域上得到周期性冲击故障特征。而采用所提出的基于稀疏共振解调方法进行信号处理后，强相干噪声得到了有效抑制,从而突出了故障特征。国家自然科学基金（51805398）陕西省自然科学基础研究计划（2018JQ5106）北京卫星环境工程研究所2019年度CAST-BISEE创新基金资助项目（CAST-BISEE2019-043

Product Market Competition and The Cash Flow Sensitivity of Cash

本文立足于产业组织理论,以2000—2013年我国A股上市公司为样本,分别以行业掠夺风险、自然边界和成本价格边际三种不同的度量产品市场竞争的代理指标,基于静态和比较静态的方法,从现金持有“存量“和“流量“两个方面的内容分别展开,分析产品市场竞争对公司现金持有量和储蓄倾向即现金一现金流敏感性的影响。结论一致表明,在其他条件不变的情况下,产品市场竞争提高了公司现金持有量;面临激烈竞争的公司表现出更大的现金一现金流敏感性,即公司使经营活动产生的现金流以现金或现金等价物的形式留存于公司内部,而且,在考虑到融资约束的影响后,样本公司在产品市场竞争和融资约束的双重作用下,表现出最大的现金一现金流敏感性。It is commonly accepted that corporate decisions are fundamentally affected by competition in product markets.In particular,financial economists have shown that the nature of product market competition may influence firms' financing policy such as cash holdings.Despite the substantial development of the literature on corporate cash holdings,little attention has been paid to the effects of product market competition on the policy of cash holdings.The purpose of this paper is to understand how product market competition affects corporate cash holdings.This paper uses the methodologies of static analysis and comparative static analysis to study the relationship between product market competition and the policy of cash holding.The content of this paper is therefore twofold.First,we try to understand how product market competition affects the stock of corporate cash holdings.Second,we try to understand how product market competition affects the flow of corporate cash holdings,that is,the effects of product market competition on the decision to retain earnings in the form of cash.The paper investigates product market competition on the effect of cash holdings and the change in cash holdings of Chinese-listed firms for the period 2000—2013.We use three different measurates of product market competition:Predation risk,Nature hedge and Price-cost margin.Predation risk is used to measure how firms' growth opportunities co-vary with those of their industry rivals,we calculate the correlation of firm stock returns with industry stock returns.The regression coefficient on the industry return is then used as the proxy for predation risk.Greater values of this measure indicate a greater predation risk and more interdependence of investment opportunities,therefore more fierce product competition.Nature hedge is calculated as the absolute value of the difference between a ? rm's ratio of net fixed assets per employee and the median ratio in its industry.To make this difference comparable across industries,the difference is then scaled by the industry range of the capital-to-labor ratio.Smaller values of this measure indicate a greater similarity of a ? rm's operations with industry counterparts and therefore fierce product competition.The price-cost margin is defined as operating income before depreciation over sales.The price-cost margin is used in most of the industrial organization(10) literature and refers to the ability of the firm to price above marginal cost.The lower value of price-cost margin indicate a more fierce product competition.Predation risk is positively correlate to cash holdings and the cash flow sensitivity of cash.Nature hedge is negatively correlate to cash holdings and the cash flow sensitivity of cash.The price-cost margin is negatively correlate to cash holdings and the cash flow sensitivity of cash.The conclusions show that:(1) Ceteris puribus,cash holdings increase with the strength of product market competition;(2)Product market competition should be related to a firm's propensity to save cash out of cash inflows,which referred to as the cash flow sensitivity of cash.The effect of product market competition on the cash flow sensitivity of cash is more pronounced in firms with greater financial constraint.The effect of product market competition on the cash flow sensitivity of cash increases with intensity of financial constraints and the strength of product market competition.The firms which face financial constraints and intense competition show the strongest the cash flow sensitivity of cash.This paper contributes to the literature extending the content of corporate cash policy,that is,analysis the effect of product market competition on the cash flow sensitivity of cash.The primary innovation of this paper is to analysis the cash holdings in comparative static methodology rather than analysis the cash holdings in static methodology,as previous papers have.Taken together,the findings lend support to and give economic meaning to a direct effect between product market competition and the corporate policy of cash holdings.国家自然科学基金项目“财务灵活性与公司财务政策选择”(71472160

海平面上升对生态系统服务价值的影响及适应措施

海平面上升导致了海岸线后退、沿海侵蚀、风暴潮加强、生物栖息地改变、湿地变迁等，引起了近海域生态系统服务价值的变化。以美国Hillsborough County为研究区域，应用SLAMM模型，模拟了海平面从2010年-2100年上升1m的情景下各类用地面积的变化，利用效益转移法评价了生态系统服务价值的变化。结果表明：①旱地面积减少3037 hm2，湿地面积增加3037 hm2，其中河口水域、滩涂、盐沼、定期洪水沼泽面积大幅度增加；季节性洪水沼泽、潮汐淡水沼泽、河流潮汐、沙滩面积大幅度减少，其它类型湿地受影响较小。②湿地总面积的增加反而导致了生态系统服务价值总量的降低，从2010年的61672万美元降低到2100年的61548万美元，这是由于净水湿地和沙滩大面积损失引起的；其中艺术娱乐、水调节、气候调节、文化精神价值将下降，水供应、栖息地保护、干扰调节和废物处理价值将上升。③防护、适应、后退三种措施分别降低、不影响、提升了生态系统服务价值，应根据其适用范围综合应用以制定应对海平面上升的适应性措施

Characterization of GlcNAc utilization system and NagC protein regulates transcription of chiI in Aeromonas caviae CB101

L8和L10是豚鼠气单胞菌(Aeromonas caviae)CB101的两株转座子突变株,突变位置发生在nagA基因,可以组成型表达几丁质酶.我们构建了基因文库,利用Southern杂交从中筛选到一个克隆子包含了三个基因:nagB、nagA和nagC.序列分析显示nagBAC的转录方向相同,而且基因的间隔仅有几个碱基.根据已有报道我们推测NagC是几丁质酶的转录调控蛋白,转座子插入nagA破坏了下游的调控蛋白基因nagC的转录和表达,从而几丁质酶成为组成型表达.我们通过构建NagC缺失突变株、凝胶阻滞迁移以及对NagC氨基酸序列的分析初步证明了NagC属于ROK(repressors,opening reading frames,and kinases)家族的调控蛋白,是chiI的转录阻遏因子.Two of Aeromonas caviae CB101 transposon mutants,L8 and L10,the transposon that insert in nagA gene can secret Chitinase constantly.We screened a clone which contained three genes:nagB,nagA and nagC from genome library of CB101 by Southern blotting.Sequence analysis showed that nagBAC had the same transcription direction and there were a few base pairs in each gap of these three genes.We presumed that NagC was the regulator of Chitinase and the insertion of transposon in nagA broke the transcription of nagC,so that Chitinase of CB101 could express constantly.We constructed nagC deletion mutant for chitinase assay,performed gel shift assay and analyzed amino acid sequence of NagC protein.Finally we proved that NagC belonged to ROK family protein and it acted as regulator of chiI primarily.国家自然科学基金资助项目(40076035

西藏色林错短纹藻属硅藻初报

对西藏色林错2015年7月附着硅藻样品进行了观察和鉴定,发现了短纹藻属的3个物种,其中圆胞短纹藻(Brachysira aponina Kützing)为中国新纪录种,其他两个物种分别为小头短纹藻B.microcephala(Grunow)Compère和透明短纹藻B.vitrea(Grunow)Ross。通过光镜和扫描电镜观察,本报道对圆胞短纹藻的形态特征进行了详细描述,对小头短纹藻的2种表型和透明短纹藻的超微形态特征进行了重新描述。圆胞短纹藻的主要特征是末端窄圆形,中央区小或为圆形,壳缝直,壳缝两侧有明显的硅质纵肋。壳缝简单,远缝端具有"M"形结构。小头短纹藻表型1主要特征为末端近头状,中央区为不对称圆形,末端为"T"形结构。小头短纹藻表型2主要特征是壳面末端头状,中部线纹辐射排列,末端平行排列。透明短纹藻主要特征是壳面为椭圆形披针形,末端伸长成头状,中央区小,卵圆形,远缝端具"T"形结构。此外本报道还比较和讨论了3物种与短纹藻属其他相似物种的形态特征,同时也对3物种的生境及分布进行了详细描述

西藏色林错短纹藻属硅藻初报

对西藏色林错2015年7月附着硅藻样品进行了观察和鉴定,发现了短纹藻属的3个物种,其中圆胞短纹藻(Brachysira aponina Kützing)为中国新纪录种,其他两个物种分别为小头短纹藻B.microcephala(Grunow)Compère和透明短纹藻B.vitrea(Grunow)Ross。通过光镜和扫描电镜观察,本报道对圆胞短纹藻的形态特征进行了详细描述,对小头短纹藻的2种表型和透明短纹藻的超微形态特征进行了重新描述。圆胞短纹藻的主要特征是末端窄圆形,中央区小或为圆形,壳缝直,壳缝两侧有明显的硅质纵肋。壳缝简单,远缝端具有"M"形结构。小头短纹藻表型1主要特征为末端近头状,中央区为不对称圆形,末端为"T"形结构。小头短纹藻表型2主要特征是壳面末端头状,中部线纹辐射排列,末端平行排列。透明短纹藻主要特征是壳面为椭圆形披针形,末端伸长成头状,中央区小,卵圆形,远缝端具"T"形结构。此外本报道还比较和讨论了3物种与短纹藻属其他相似物种的形态特征,同时也对3物种的生境及分布进行了详细描述