多头滚刀在异形锥花键加工中的应用

花键滚刀是常用的花键加工方法之一。本文针对有异形截面齿形的锥花键,提出了一种采用有特殊结构的多头滚刀滚切的方法,很好地解决了异形锥花键滚切加工的技术难题。     

锚固地梁技术在人工边坡治理中的应用研究

峡口码头高切坡,处于硬软岩性的交接部位,岩体中裂隙发育,多为层状结构和碎裂结构,在切坡初期,常产生规模不等的滑移破坏。基于小变形的假设和有限元分析基础上,确定工程治理措施,是紧密结合工程实践的重要课题。     

高速切削技术及其在我国的发展

高速切削能力和技术水平已经成为衡量一个国家先进制造技术水平的重要标志。在介绍高速切削技术的发展及机理高速切削的特点基础上．探讨了高速机床的相关系统、高速切削的应用和高速切削需要解决的问题等．并分析了这种高新技术的实施条件以及在我国的发展现状。     

Cost control based on value chain paying equal attention to earning more income and cutting down expense

According to the idea of cost control based on the value chain, several important factors are necessary. Firstly, it is necessary to have enough resources, which must be invested to create advantageous value chain based on customer value. It is also necessary to be sure of the cost advantage of the value chain. Secondly, the consumption of resources must be reduced as much as possible to enable the smallest operating cost for the value chain and make sure of the cost advantage based on maximum business value or profit. It is a kind of cost control from the whole view of creation and supply of value. In practice, it is also a kind of cost control system based on the value chain. It includes enough control and necessary resource investment from the view of the value creation, and keeps consumption of resources to a reasonable level from the view of the value supply. The main object of the first factor is to construct the advantageous value chain from creating customer value; and the second factor is to strengthen the advantageous value chain from supplying or producing customer value. Therefore it is a new kind of idea to explore this cost control from the whole view of creation and supply of value. It is more profitable for businesses to gain sustainable competitive advantage.     

热轧带钢滚筒式切头飞剪关键技术进步

总结了30年来热轧带钢滚筒式切头飞剪关键技术进步,包括机械结构创新设计和最优化剪切系统等。     

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。