轴流通风机比A声级噪声限值的探讨

论证了现行JB/TQh341-84部颁标准中用比A声级限值来判定轴流通风机噪声特性的不准确性,并提出了A声级限值标准及对高压大流量轴流通风机应采取的降噪措施。     

Liquidity in Asset Markets With Search Frictions

We develop a search‐theoretic model of financial intermediation in an over‐the‐counter market and study how trading frictions affect the distribution of asset holdings and standard measures of liquidity. A distinctive feature of our theory is that it allows for unrestricted asset holdings, so market participants can accommodate trading frictions by adjusting their asset positions. We show that these individual responses of asset demands constitute a fundamental feature of illiquid markets: they are a key determinant of trade volume, bid–ask spreads, and trading delays—the dimensions of market liquidity that search‐based theories seek to explain.     

价格跳跃前大中小单的行为特征和信息含量

利用中证800指数成分股3年的分笔交易数据,将股票成交订单分成大单、中单和小单,然后分析跳跃前的交易指令与跳跃的关联性及其对跳跃的预测能力.对跳跃样本和匹配有消息发布的跳跃样本进行事件分析和回归分析,发现跳跃前有明显的、逐渐加强的、与跳跃方向相对应的异常交易,而且异常交易指令与跳跃的发生概率、方向、大小和匹配的信息有不同程度的显著关联性;进一步的预测分析也发现,在控制流动性指标后,异常交易指令可以提升模型对跳跃的预测效果.这些结果显示市场在跳跃前存在着信息泄露,且信息泄露随时间扩散.此外,事件分析、回归模型和预测效果均显示:跳跃前中单的信息含量一般高于大单和小单,说明中国股市在极端价格变化前存在隐秘交易