纳米二硫化钼对菜籽油摩擦学性能的影响

采用沉淀法,以钼酸铵和硫化铵为原料制备了纳米二硫化钼微粒,通过透射电子显微镜、X射线衍射和激光粒度分析仪对其结构进行了表征,利用四球摩擦磨损试验机测定了添加不同含量纳米二硫化钼菜籽油润滑剂摩擦学性能,采用扫描电子显微镜和能量散射谱仪观察分析了磨损表面形貌及表面元素组成。     

对SBS改性沥青的性能研究

对SBS改性沥青进行不同温度及不同贯入时间下的针入度试验,以此来评价沥青的流变特性及路用性能;分析了SBS改性沥青的软化点随着混合过程的变化而出现的复杂变化,并通过不同温度和速率条件下的延度试验来分析改性沥青的流变特性。     

混凝土保护层厚度的调查与分析

本文通过大量的工程实例数据,分析造成其梁、板保护层厚度不合格的原因;分析了不同保护层厚度对简支梁力学性能的影响,并利用ANSYS有限元软件对4根不同保护层厚度情况下的钢筋混凝土梁进行了有限元分析。研究表明,保护层厚度是否满足要求对保证工程质量具有重要的作用,因此应重视保护层的保证措施;保护层检测时,应注意选取合适的检测部位以及检测数量,保证检测环境的稳定;较大的保护层厚度可以较好地保护钢筋,但是梁的挠度增加,进而降低其承载能力。故应选用合适的保护层厚度,从而降低工程造价。     

Agricultural price transmission across space and commodities during price bubbles

This article investigates agricultural price transmission during price bubbles. The empirical approach concerns the horizontal transmission of cereal prices both across different market places and across different commodities. The trade policy intervention put forward to mitigate the impact of price exuberance is considered. The analysis is performed using Italian and international weekly spot (cash) price data over years 2006–2010, a period of generalized turbulence of agricultural markets. Firstly, the properties of price time series are explored; then, interdependence across prices is specified and estimated by adopting appropriate cointegration techniques. Results suggest that the bubble had only a slight impact on the price spread and the temporary trade‐policy measure, when effective, has limited this impact.     

行政私法行为及其法律控制

为了适应现代行政管理的需要,行政机关在使用权力手段来实现行政目的的同时,越来越青睐采用相对温和、民主的行政私法行为来实现行政目的。如何界定行政私法行为,如何对行政私法行为进行法律控制,成为我们迫切需要解决的课题。     

An Empirical Investigation of the Effect of CFO Power on Disclosure Quality

We examine the association between chief financial officer (CFO) power and disclosure quality, measured using financial statement disaggregation disclosure and analyst forecast disclosure. Empirically, we validate that CFO power, measured by multiple dimensions, is positively associated with firms’ disclosure quality. We also find that this positive association between CFO power and disclosure quality is stronger when firms exhibit higher governance monitoring and accounting quality. Further analysis shows that our main results hold across multiple disclosure quality tests. Our findings are robust to addressing endogeneity issues using two-stage least squares, Heckman selection bias, and propensity score matching analyses. The results highlight the importance of CFO power for the accounting reporting process and decision-making.     

Efficient estimation and computation for the generalised additive models with unknown link function

The generalised additive models (GAM) are widely used in data analysis. In the application of the GAM, the link function involved is usually assumed to be a commonly used one without justification. Motivated by a real data example with binary response where the commonly used link function does not work, we propose a generalised additive models with unknown link function (GAMUL) for various types of data, including binary, continuous and ordinal. The proposed estimators are proved to be consistent and asymptotically normal. Semiparametric efficiency of the estimators is demonstrated in terms of their linear functionals. In addition, an iterative algorithm, where all estimators can be expressed explicitly as a linear function of $Y$, is proposed to overcome the computational hurdle for the GAM type model. Extensive simulation studies conducted in this paper show the proposed estimation procedure works very well. The proposed GAMUL are finally used to analyze a real dataset about loan repayment in China, which leads to some interesting findings.     

High-impact information types on market value: property appraisers’ information sources and assessment confidence

This explanatory paper describes and analyses which types of information professional property appraisers perceive to have the most impact on a commercial property’s estimated market value, which information sources they primarily use, and how reliable they perceive the information sources to be. The paper also investigates whether appraisers’ perceptions differ depending on the location of the business. A sample of 67 authorised property appraisers in Sweden was surveyed using the repertory grid technique as a questionnaire tool (to investigate unconscious behaviour), and non-parametric statistics. Analyses of the data show that four types of information have the greatest impact on estimated market value: the local environment and location are perceived as reliable, and property appraisers have confidence in those assessments; rental income seems problematic, because the property owner is the major source of information; and property appraisers are not confident in assessments based on discount rates. This pattern holds for various geographical locations.     

What matters most? Stakeholders’ perceptions of river water quality

The need to integrate stakeholders’ views into environmental policy is increasingly gaining attention because this offers the opportunity to design sustainable and synergistic environmental strategies. Understanding and integrating the views of resource users into policy design and implementation could help address the most important challenges, gain community support, enhance project ownership, and avoid policies being rejected by local people. As a result, research in environmental management has focussed on stakeholders’ perceptions of river water quality and how to integrate such views into policy. While existing studies offer insights into the different ways in which stakeholders evaluate river water quality and potential factors influencing judgements, they appear to be limited in a number of ways. First, most of these studies focus on developed countries and may have limited contextual relevance to the developing world. Moreover, past studies focus on segments of society such as farmers and mainly on wastewater for agriculture. These shortcomings may limit our understanding of the topic and our ability to design effective policies to address water quality problems. Drawing on survey data from the Wenchi municipality in Ghana, we examine public perceptions of what constitute important measures of river water quality as well as factors influencing such judgements. Results suggest that while variables such as taste, colour, smell and litter are important, the presence of faecal matter in and/or around the river was rated the most important measure of river water quality while depth of river was the least important. Results further suggest that education, age, number of years a person had lived in a community, depth of river and the presence of aquatic vegetation influence water quality judgements. The findings of this research provide insights into what policymakers and regulators need to consider when attempting to influence behaviours in relation to water resources. We note, however, that while public perceptions of river water quality could guide water management policies, scientific measurements of water quality must not be replaced with stakeholder perceptions. This is because aspects such as ecological integrity may not be important to segments of the public but are an important aspect of water management. This is reinforced in the present study as there seems to be a lack of concern among the participants regarding river depth – an important factor for habitat provision and pollution dilution.     

17-4PH马氏体沉淀硬化不锈钢锻造开裂问题的解决措施

17-4PH马氏体沉淀硬化不锈钢材料的用途越来越广,不过其产品在锻造过程中表层开裂特别严重。钢锭是通过电渣重熔冶炼出来的,无重熔时暂留缺陷。钢锭通过机床加工两端和车光外径,在鐓粗过程、拔长过程、压下过程都会产生严重开裂事故,导致生产不能正常进行。为了解决这种情况,在本文的分析研究中,对其原因进行深入分析,并提出相关解决措施。