潜油电泵泵轴寿命可靠性分析

统计了大庆油田近五年应用的4123套潜油电泵机组，针对248件失效泵轴的寿命进行分布检验分析，验证了其符合威布尔分布规律,并进行了可靠性评定。应用编制的工程软件可计算不同样本下泵轴寿命的概率分布规律，确定其可靠性指标，实现对泵轴使用可靠性的定性分析和定量评定，为进一步开展潜油电泵机组可靠性研究提供必要的基础数据和数据处理手段。     

Do specialized board committees impact the transparency of corporate political disclosure? Evidence from S&P 500 companies

This study examines how the specific attributes of one type of voluntary corporate governance mechanism, a specialized political contribution committee, improves the transparency of corporate political disclosure (CPD). The results demonstrate that the existence of a committee that establishes and reviews key political activities and disclosure policies, particularly one composed entirely of outside directors, significantly enhances the transparency of corporate political disclosure, and reveal that an under-studied board committee, the political contribution committee, effectively improves CPD transparency. The results are consistent with agency theory and further support the more generalizable idea that specialized governance mechanisms (e.g., a political contribution committee) and fully independent committees lead to more transparent disclosure. Finally, the results suggest that the existence of a political contribution committee and committee independence are channels to improve CPD transparency. Public-policy makers and regulators seeking to enhance CPD transparency might consider implementing regulations that mandate or recommend these governance mechanisms as best practice.     

Annual report readability and corporate agency costs

Annual reports are the main sources of information for outside investors’ investment decisions and enable shareholders to supervise the management. Difficulties with the readability of these reports may therefore have serious consequences. Using 19,221 firm-year observations of Chinese A-share listed firms from 2001 to 2015, we investigate the association between annual report readability and corporate agency costs, where readability is proxied by report file length and/or file size. We find that firms with better annual report readability experience lower agency costs, and the negative association between readability and agency costs is more pronounced in firms with higher external audit quality, internal control quality or analyst coverage. These results hold after several robustness checks. The positive effect of annual report readability is stronger in private firms than in state-owned enterprises, and becomes stronger after the implementation of new accounting standards in 2007. Readable annual reports can help in monitoring corporate insiders’ opportunistic behavior and thus reduce agency costs.     

"竞争"抑或"继承":农地产权如何影响农民生育性别偏好

"重男轻女"被视为乡土中国的重要传统之一.已有研究多聚焦于男女不平等的社会问题,但较少关注男女性别偏好所反映出的农民土地情结以及中国农村土地制度改革可能带来的乡土社会生育观念的变化.本研究表明,农民生育"重男"的性别偏好不仅是农村家庭传承中"继承"观的反映,也是农地产权不稳定或不安全时壮大地权博弈力量的需要.基于2016年中国劳动力动态调查数据的检验结果显示,农地调整和农地确权均会强化农民"重男轻女"的生育性别偏好.其中,农地调整会诱导农民对生育男孩数量上的偏好,生男孩成为"弱者的武器";农地确权并未激励农民在生育男孩数量上的"占优",而仅限于"有".前者表达产权争夺的"竞争性",后者表达产权排他的"继承性".文章强调,"重男轻女"观念隐含着不同的产权含义.     

Effects of cross-border capital flows on stock returns of dual-listed firms in mainland China and Hong Kong: Evidence from a natural experiment

This study analyses the effects of the Shanghai–Hong Kong Stock Market Connect policy on the price disparity between A-shares and H-shares of dual-listed companies (DLC). Using a difference-in-difference estimation method, we show that the policy decreases the relative twin cumulative abnormal returns of treated DLC by 3% and narrows the price gaps between A-shares and H-shares. We determine that the rising demand for H-shares, which are newly accessible by mainland investors, drives the price of H-shares up. By contrast, the price of A-shares remains unchanged. Further analysis reveals that cross-border capital flow is the main force of the policy.     

A Study on Firms with Negative Book Value of Equity

This paper studies the puzzling negative book equity phenomenon among US public firms. Our evidence suggests that negative book equity firms exhibit heterogeneous characteristics. We show that a great portion of these firms, while operating at excessive capital structure with leverage ratio over 100%, are financially and operationally healthy. These healthy negative book equity firms increase their debt primarily motived by a need for funds to fulfill investment demand. We also find that the off‐balance sheet intangible assets and quality of intangible assets play an important role in determining the true debt capacity of these firms.     

口服液中粗多糖提取方法的改进

为了考察改进苯酚-硫酸法测定保健品口服液中粗多糖提取方法的可行性,以某保健品口服液为样品,对采用苯酚-硫酸法测定粗多糖含量时的多糖的不同提取条件与测定进行一个较为详细、系统的研究。结果表明:样品经改进提取条件后测定,试验结果表明有良好的线性关系,精密度RSD值为0.69%,稳定性良好,平均加标回收率为101.0%。该方法改进后提高了该实验的精密度和准确度,重现性高,并使结果更加可靠和稳定。     

水中酚类化合物的检测方法研究进展

酚类化合物是环境水中的重要污染物之一,对人类健康和生态环境有很大的潜在危害。为了更好地检测其在各类水体中的含量,研究更高效、稳定、准确的测定方法很有必要。本文介绍了几种常见的水中酚的预处理与检测方法,希望能在实际的环境监测中发挥一定的作用。     

Does IFRS Adoption Increase the Accuracy of Chinese Analysts’ Forecasts?

This article investigates the impact of International Financial Reporting Standards (IFRS) adoption on the accuracy of Chinese analysts’ earnings forecasts. We find that after IFRS adoption, the accuracy of Chinese analysts’ forecasts decreases rather than increasing as they do in developed countries documented by the extant literature. Further investigation finds that this decrease is associated with a fair value measurement of financial assets held for trading. Our finding provides empirical evidence supporting the argument that the effectiveness of IFRS adoption could be negative in a developing country depending on its setting and fair value measurement brought about by IFRS could contribute to the negative effect in this setting.     

液相色谱-原子荧光光谱联用法测定水产干制品中甲基汞含量不确定度分析

本文对液相色谱-原子荧光光谱联用法测定水产品中甲基汞含量进行了不确定度分析,分析了整个测试过程中不确定度的来源,并对各不确定度分量进行了计算。水产品中甲基汞的含量为0.00111mg/kg,扩展不确定度为0.000 122 mg/kg(k=2)。