多零件数控加工技术的研究与应用

论述了多零件数控加工技术的应用现状及关键技术问题，介绍了太钢设备安装公司对多零件数控加工技术的研究与应用，对提高数控设备利用率和加工效率、改善产品质量有一定的借鉴作用。     

强化财务管理与控制增强企业核心竞争力

介绍了企业如何强化资金的使用效率，以及如何通过加强企业内部财务管理与控制来提高企业的核心竞争力。     

对水土资源可持续发展的再认识

阐述了水环境的概况,探讨了土地资源的恶化与人类回归自然的关系,指出保护水土资源、修复生态环境是每个公民的义务和责任,人类要倍加珍惜、保护环境,对已破坏的水土环境加以尽快修复。     

探索规律,建设高水平二级院务办公室

文章就高等学校二级管理模式,从二级学院管理结构调整、管理目标设定、办公室队伍建设和办公室环境营造等方面,论述了提高二级学院办公室管理效率的有效途径和方法。     

载流子迁移率对单层有机发光二极管复合效率的影响

建立了在单层有机发光二极管中电场强度不太大(E≤104Vcm)的情况下,载流子注入、传输和复合的理论模型.通过求解非线性Painleve方程得出了电场强度随坐标变化的解析函数关系式以及电流密度随电压变化关系,给出了电流密度以及器件的复合效率在不同的载流子迁移率情况下随电压变化关系图像.结果表明,复合效率受载流子迁移率影响较大,在器件中多数载流子应具有较低的迁移率,而少数载流子应具有较高的迁移率,这样有利于载流子的注入和传输,从而可提高发光效率.并且得出当空穴迁移率大于电子迁移率时,复合区域偏向阴极,反之亦 关键词： 单层有机发光二极管 复合效率 迁移率     

确定巷道掘进炮眼深度的一种方法

本文提出了一个以炮眼数量、钻眼速度、炮眼利用率和装岩生产率等技术要求及施工组织与管理要求为约束,以求得每米巷道掘进费用最小为目标的规划模型,并应用该模型,借助计算机求得一个具体条件下的炮眼深度。     

A Note on Relative Efficiency of Axiom Systems

We introduce a notion of relative efficiency for axiom systems. Given an axiom system A_β for a theory T consistent with S¹₂, we show that the problem of deciding whether an axiom system A_α for the same theory is more efficient than A_β is II₂-hard. Several possibilities of speed-up of proofs are examined in relation to pairs of axiom systems A_α, A_β, with A_α ? A_β, both in the case of A_α, A_β having the same language, and in the case of the language of A_α extending that of A_β: in the latter case, letting Pr_α, Pr_β denote the theories axiomatized by A_α, A_β, respectively, and assuming Pr_α to be a conservative extension of Pr_β, we show that if A_α — A_β contains no nonlogical axioms, then A_α can only be a linear speed-up of A_β; otherwise, given any recursive function g and any A_β, there exists a finite extension A_α of A_β such that A_α is a speed-up of A_β with respect to g. Mathematics Subject Classification: 03F20, 03F30.     

Oblique-Incidence Characteristics of a Parallel-Aligned Nematic-Liquid-Crystal Spatial Light Modulator

We have developed optically-addressed and electrically-addressed liquid crystal spatial phase-only light modulators having no pixelized structures. We obtained a large depth of phase-only modulation and high diffraction efficiency based on the electro-optical characteristics of a parallel-aligned nematic liquid crystal. These spatial light modulators (SLM) are of the reflection type, so there would be a loss of power in the readout light from the half mirror, which was set up so as to separate the incident and reflected lights. To optimize the characteristics of a reflection type spatial phase-only light modulator, we have proposed an oblique incident optical readout setup. We have examined the effect of conditions such as the polarization direction and the incidence angle of the readout light, and the orientation of liquid crystal molecules in the SLM. High diffraction efficiency close to the theoretical maximum value was obtained by adjusting the above conditions. The simulation analysis can well explain the experimental results of phase modulation.     

EFFICIENCY OF INVOLUTE GEAR DRIVES WITH UNDERCUT PINIONS USED IN WRIST WATCHES

In wrist watches gear drives with undercut pinions are used. Those pinions have got a tooth number as few as 5—7. The efficiency of such gear drives is important because of the limited energy supply. The mean efficiency of gear drives can be expressed as E_m=1/(φ_2-φ_1)(integral from φ_1 to φ_2(E(φ)dφ)) in which ~0_1, ~_2 are the approach angle and the recess angle respectively. In the discussion we assume that the friction coefficient between the two tooth flanks is constant because the sliding speed is relatively low in wrist watches and the main purpose is to find out the relation between gear parameters and its efficiency rather than to calculate the exact value of the efficiency. In normal conditions ~o_1 and ~o_2 can be found from the gear geometry without much difficulty. However when the pinion is an undercut one we have to first find the forming diameter where the involute profile starts. In this paper equations for the computation of the efficiency and the contact ratio of those gear drives are discussed.     

对我国建筑施工企业总体生产技术效率的研究──数据包围分析(DEA)方法的模型与应用

运用“数据包围分析”（ＤＥＡ）经济计量的方法，建立数学模型，对我国建筑施工企业１９８４～１９９５年间的整体生产效率进行分析和研究，对各年的生产效率值和变化关系，生产规模以及变量的理论值等问题进行探讨。