加强型平头齿刀在广州砂砾地层里的应用分析

通过加强型平头齿刀在广州地铁三号线北延线砂层里的应用，能够比普通型平头齿刀达到更长的使用寿命和掘进距离．对盾构机刀盘的磨损起到了较大程度的保障。文章结合实例，针对平头齿刀的切削角度、刀具形式、材料工艺以及耐磨堆焊的分布形式进行了研究。     

Vehicle head restraint positioning knowledge and behaviours in a sample of Irish drivers

A correctly positioned vehicle head restraint (HR) can reduce whiplash injury risk in collisions, however, HRs are often sub-optimally positioned. The primary aim of this study was to investigate vehicle HR position and driver knowledge of correct HR positioning in an Irish population. Secondary aims were to investigate the associations with driver age, gender and vehicle age. Data collection involved HR measurement and a driver questionnaire (n = 110). Just 27% of drivers had optimal HR positioning, while 30% had poor or marginal positioning. Newer vehicles (<5 years old) had better positioned HR in the horizontal plane (p = 0.036), than older vehicles. Younger drivers (<30 years) were more likely to have poorer positioning of HR (p = 0.002), than the 30 years or over group. Females were more likely to have better vertical positioning of their HR (p = 0.003) than males. Driver knowledge of correct position was variable, and not associated with actual HR position, with 65% knowing the correct vertical positioning standard but only 27% identifying the correct horizontal position. Many drivers have inadequately positioned HR, which needs to be addressed by improved vehicle design and public education.     

新形势下护士长在护理管理中的角色及作用

社会的发展和医疗模式的改变促使护士长自身的素质和管理能力的提升成为新形势下的必然要求。护士长应当充分发挥其角色作用,将现代的科学管理方式应用到护理管理工作中,同时树立职业的管理形象,以应对新的护理形势。     

森林采伐限额管理制度研究综述

在查阅大量文献的基础上，将采伐限额管理制度的研究分为三个阶段，对森林采伐限额管理制度的研究现状进行了分析，主要包括采伐限额管理制度的必要性研究，超额采伐的原因分析，采伐限额管理制度对林农经营的影响研究，以及采伐限额制度存在的问题分析，提出了森林采伐限额管理制度需要深化研究的内容。     

Concentration of competing retail stores

The geographical concentration of stores that sell similar commodities is analyzed using a two-dimensional spatial competition model. A higher concentration of stores attracts more consumers with taste uncertainty and low price expectations (a market-size effect), while it leads to fiercer price competition (a price-cutting effect). Our model is general enough to allow for the coexistence of multiple (possibly) asymmetric clusters of stores. We provide sufficient conditions for the nonemptiness of equilibrium store location choices in pure strategies. Through numerical examples, we illustrate the trade-off between the market-size and price-cutting effects, and provide agglomeration patterns of stores in special cases.     

禁伐背景下林区最低生活保障制度探析——以大兴安岭国有林区为例

通过对大兴安岭林区最低生活保障制度的调查发现:大兴安岭林区最低生活保障制度存在城乡保障标准水平差距大、保障标准确定不合理以及动态调整机制不健全等问题。在全面禁伐实施后,这种情况将会更加严重。因此,应提高林区人民的低保保障水平,使之不至于因"禁伐令"的实施而使生活陷入困难。基于此建议:提高农村低保标准,缩小城乡差距,逐步实现低保制度城乡一体化,不断完善动态调节机制,加强中央财政转移支付力度。     

森林采伐限额制度研究综述

目前森林采伐限额制度研究主要集中于采伐限额制度能否有效保护森林资源、采伐限额制度实行的必要性、采伐限额制度存在的问题以及解决对策这几个方面展开。通过对国内外文献的梳理,现有研究存在缺少对个案的研究、缺少实证分析以及实证分析所采用方法准确性证明力低、采伐限额强度设置依据标准不清、未提出具体的采伐红线以及处罚强度设置标准、对研究中所提出的替代性制度的可行性证明不够等问题。因此未来的研究可以更多的关注某一地区采伐限额制度的效益、采伐红线与处罚管理强度的设置以及替代性制度效用等方面。     

等螺旋角锥度棒铣刀制造方法实践

等螺旋角锥度棒铣刀具有切削平稳、切削效率及耐用度高等特点。由于锥度棒铣刀的刀坯是一个圆锥体,当它有一个不变的螺旋角ω时,它的导程是不等的,这就给制造带来了困难。而找出其几个主要参数之间的函数关系,利用数控机床加工是一种便捷的方法。文本对其函数关系进行了推导,对加工其螺旋槽数控程序的编制及加工过程中需注意的几个问题作了介绍。     

制热的新途径——液力冲击制热

文章介绍了一种国内外尚无先例的制热的新方法——液力冲击制热。并阐述了它的理论价值、经济意义、实用意义以及能容高的特点。还简要分析了冲击制热的工作原理及计算。     

Social comparison among competing firms

Extending social comparison theory to the context of interfirm competition, we investigate whether and under what conditions firms may benefit by deviating from consumers' views concerning firm comparisons. Based on all of the possible dyadic competitive comparisons among the 26 automakers in the United States, we found that: (1) a focal firm enjoys a greater increase in sales than the target firm when it compares itself with a more reputable target firm, even though consumers do not perceive the focal firm to be comparable to the more reputable firm; and (2) a focal firm enjoys a greater increase in sales than the target firm when it avoids comparison with a less reputable target firm, even though consumers compare the focal firm with the less reputable firm. Copyright © 2011 John Wiley & Sons, Ltd.