基于西门子PLC技术的机械手控制系统设计

气动机械手具有结构简单,定位精度高,价格低廉等特点,逐渐被越来越多的企业所使用。本文根据公司传统生产线需人工进行物料抓取的现状,设计一种由可编程控制器控制、用气缸驱动的机械手来实现生产线的自动化生产。在设计过程中,重点介绍了机械手的气动装置和PLC控制系统的设计。     

翻边机上夹紧油缸弯曲受力分析

二步法旋压机包含翻边机、压鼓机。通常封头厂希望翻边机(在设备规格确定的条件下)能加工厚的封头,同时要求加工封头最小直径,这二者之间很多时候是矛盾的,所以如何配置的上夹紧油缸外径最小,是加工封头最小直径的关键。     

支架现浇箱梁施工技术

在特殊地理环境中,在线型、受力、跨度等各方面有特殊要求时,由于预制梁满足不了这些,需要使用支架现浇箱梁。现浇箱梁有抗扭能力强,跨度大,横向抗弯刚度大,稳定性好等优点。下面结合工程实例介绍一下支架现浇箱梁施工技术。     

后张法预应力箱梁施工工艺及质量控制

本文通过介绍福银高速九江大桥北引道工程汪垏特大桥的结构形式,对后张法预应力箱梁施工的流程进行了介绍。并且根据实例对预应力钢筋、预应力孔道以及锚垫板、模板、混凝土的浇注以及养护等进行了分析,通过分析后张法预应力箱梁的施工工艺,总结施工各环节中需要注意的问题,为保证工程的施工质量的打下了坚实的基础。     

Where do We Go From Here? New Perspectives on the Black Box in Strategic Human Resource Management Research

The main objective of the present research is to briefly review the strategic human resource management (HRM) literature from multilevel theoretical perspectives to summarize what we know about mediating mechanisms in the HR–performance relationship. By doing so, we highlight future research needs to advance theoretical understanding of the ‘black box’ in strategic HRM research. Furthermore, by offering additional theoretical perspectives that can be used to understand the mediating mechanisms at different levels, we suggest future research directions that capture the complexities associated with strategic HRM through a multilevel theoretical lens. Implications of the model are discussed.     

液化石油气钢瓶安全性要求与检验

分析和介绍了液化石油气钢瓶产品安全性的具体要求及产品检验考核的目的,并对使用及维护中对安全的构成不良影响的现象进行了分析和说明,为检查和使用液化石油气钢瓶的有关方面提供参考。     

股价崩盘风险、信息环境与企业现金调整

以我国2009—2016年沪深上市公司数据为样本，探究了股价崩盘风险、信息环境对企业现金调整的影响。研究发现：股价崩盘风险越大，企业现金调整速度越快，且这种正相关关系对于分析师跟踪数量较少、机构投资者持股比例少的企业而言更为显著。进一步考察股权性质在企业现金调整速度中的影响，发现国有企业与民营企业面对股价崩盘风险的现金调整速度并不具有显著差异，但是对于民营企业而言，更多的分析师跟踪和机构投资者持股将显著降低企业应对股价崩盘风险的现金调整速度，信息环境对于国有企业的作用并不显著。     

A hybrid clustering and classification approach for predicting crash injury severity on rural roads

As a threat for transportation system, traffic crashes have a wide range of social consequences for governments. Traffic crashes are increasing in developing countries and Iran as a developing country is not immune from this risk. There are several researches in the literature to predict traffic crash severity based on artificial neural networks (ANNs), support vector machines and decision trees. This paper attempts to investigate the crash injury severity of rural roads by using a hybrid clustering and classification approach to compare the performance of classification algorithms before and after applying the clustering. In this paper, a novel rule-based genetic algorithm (GA) is proposed to predict crash injury severity, which is evaluated by performance criteria in comparison with classification algorithms like ANN. The results obtained from analysis of 13,673 crashes (5600 property damage, 778 fatal crashes, 4690 slight injuries and 2605 severe injuries) on rural roads in Tehran Province of Iran during 2011–2013 revealed that the proposed GA method outperforms other classification algorithms based on classification metrics like precision (86%), recall (88%) and accuracy (87%). Moreover, the proposed GA method has the highest level of interpretation, is easy to understand and provides feedback to analysts.     

The “timber box” effect for premium wines

The present research aimed to examine the effectiveness of using luxurious external packaging boxes to improve customer perceptions towards premium wine. Consumers viewed images of wine presented in four types of packaging: (1) no box; (2) a plain wooden box; (3) a wooden box with explanatory text; and (4) a wooden box with both explanatory text and a transparent window; and completed a survey measuring product attitude, willingness to pay, perceived luxury, and perceived risk associated with the product. Results indicated all box types resulted in higher willingness to pay, and that the explanatory and transparent boxes were able to elicit significantly higher product attitudes than the plain box or no box at all. The positive effects of the transparent and explanatory boxes were fully mediated, or explained, by perceived luxury. Furthermore, the negative effects underlying the plain box conditions were partially mediated by perceived risk. The present study was the first to empirically investigate the psychological mechanisms responsible for the influence of packaging, and to examine how perceived product luxury and perceived risk underlie these effects. Managerial implications are discussed, and recommendations are provided for retailers.     

Operating cash flow opacity and stock price crash risk

We examine the relation between operating cash flow (OCF) opacity and stock price crash risk. We find that OCF opacity is positively associated with future stock price crash risk after controlling for accruals opacity and other determinants known to influence crash risk. This finding suggests that OCF opacity facilitates bad news hoarding and enables managerial resource diversion, which in turn increases crash risk. We also find that the positive relation between OCF opacity and crash risk is more pronounced when external monitoring is weak, information asymmetry is high, OCF importance is low, and cost of accruals management is high. Overall, our evidence highlights the severe consequence of OCF opacity in that it boosts crash risk; our study should alert the researchers, investors, and regulators to pay more attention to OCF management.