浅谈回弹法检测混凝土抗压强度

回弹法是一种简便的推定混凝土构件抗压强度的方法,在我国应用十分广泛。结合实际工作,对回弹法检测混凝土抗压强度谈一些体会和看法。     

浅谈爆炸硬化辙叉在朔黄线的应用

随着西煤东运第二条大通道朔黄铁路运量的增加,运输压力越来越大。自90年代以来,铁路运输飞速发展,提速、重载给工务线路带来了一系列问题,尤其是辙叉已远远不能满足铁路提速重载的要求。2011年开始朔黄铁路在黎明居车站3号、4号岔位和神池南车站2083#、2043#岔位陆续试用了60-12#和75-12#爆炸硬化辙叉。实践表明,爆炸硬化辙叉提高了道岔使用寿命,增大了安全系数,创造更多的经济效益和社会价值。     

中小企业集合债券发行前期工作应注意的事项

本文从中小企业集合债券的含义谈起,先后阐述了中小企业集合债券的特点、发行意义、目前发行情况和发行前期工作应注意的事项,着重对发行前期工作应注意的事项进行了阐述。     

深基坑中土层锚杆工作性状研究

Rock-Soil Anchorage is an important branch of geotechnical engineering. The basic Theory of stucture which depends on shearing strength of stratum around anchorage,or keeping the stabilisation of excav...     

A re-examination of the impact of credit ratings and economic factors on state bond yields

In this article we re-examine the impact of credit ratings and economic factors on state bond yields using a two-step model. In the first step, we adopt an ordered probit technique to obtain consistent estimates of state bond default risk. In the second step, we estimate state bond risk premiums using a regression analysis with a categorized risk variable obtained from the first step. Similar to Terza (1987) and Hsiao (1983), the model involves a categorized ordinal explanatory (rating) variable. However, our two-step model deals with a case where category thresholds are unknown and dependent on economic factors. The model provides consistent estimates for the effects of ratings and economic factors on state bond yields. Contrary to previous findings, we find that state bond yields are mainly affected by fundamental economic variables.     

Perceptions of postretirement benefit obligations by bond rating analysts

This research examines the measurement and impounding of alternative measures of a corporation's other postretirement benefits obligation (OPEBs) by an important segment of the capital markets. The Kaplan and Urwitz (1979) model is used as a benchmark from which to assess the importance of an added OPEB variable in the bond rating process. Using the corporate bond rating as the dependent variable, multiple measures of the OPEB obligation are inserted individually as an added independent variable into an N-chotomous probit model. The results for 1987 and 1988 indicate that measures calculated from publicly available information produce highly significant results. The developed postretirement liability measures are found to provide relevant and material information regarding the risk level of a firm's bonds as represented by its bond rating. This insight concerning the additional risk represented by a firm's postretirement benefits is beyond that supplied by the firm's pension information. This suggests that the additional investor default risk attributed to a firm's OPEB can be reasonably proxied by data found in the company's annual report footnote disclosures.     

我国企业债券市场发展及其对商业银行的影响

本文通过对我国企业债券市场历史和现实的分析提出以下观点:企业债券市场发展有助于商业银行优化资产组合并提升资产收益和流动性,有助于提高商业银行利率定价水平并增强银行体系稳定性.与此同时,企业债券市场发展也使商业银行面临更复杂的信用风险和市场风险.而信用风险和市场风险相互作用和影响,形成风险"放大"效应.基于上述分析,本文认为:商业银行应认清优劣势,从发展战略角度为企业债券业务定位,将企业债券业务作为"入世"后银行业全面竞争的重点之一;商业银行应构建企业债券业务的全面风险管理框架,包括信用风险、市场风险等;商业银行应加强对企业债券创新产品的研究.     

The Effect of Junk Bond Defaults on Common Stock Returns

This paper examines the effect of junk bond defaults on common stock returns. The evidence indicates that stockholders uncover the signs of financial distress long before the default date. Stock prices fall sharply at the time of the default announcement. Although stocks of fallen angel sample recover slowly and steadily after the default announcement, stocks of the original-issue junk bond sample continue to decline. On average, bankrupt firms suffer larger negative stock returns than defaulted firms not only at the time of announcement, but also in both pre- and post-event periods.     

固体火箭发动机粘接界面湿热老化实验

对固体火箭发动机粘接界面试验件进行了不同湿热条件下的加速老化试验,并测量了不同老化时间粘接界面的扯离强度,描述了湿热老化试验和性能测试中的试验现象,结合复合材料微粘接结构吸湿规律对试验现象和撤离强度随老化时间变化曲线进行了分析。研究结果表明:衬层-推进剂粘接界面是固体火箭发动机粘接结构中最薄弱环节,应予以重点考虑；湿热老化促进了环境水分从衬层–推进剂界面向推进剂内部的扩散和渗透,致使弱边界层向推进剂内部扩展,导致了衬层-推进剂界面粘接强度的降低。试验件平均扯离强度随老化时间呈下降趋势,中间有一个强度趋于稳定的平台期。 