基于螺旋线铣削的螺旋面粗加工数控编程方法

在螺旋曲面的数控粗加工中 ,采用一般的编程方法得到的刀具路径在实际应用中存在加工时间长、效率低、对刀具要求高等缺点。基于螺旋线数控铣削的螺旋曲面粗加工的方法可大大提高加工效率 ,减少刀具磨损 ,降低加工成本。     

从"断章取义"到"以意逆志"——孟子复原式解释理论的产生与演变

孟子"以意逆志"说历来被公认为中国文论中关于文学解释的最具影响力的理论。尽管学界深谙这一理论的历史意义,却很少有人关注过先前观诗传统对它的影响,后来《毛诗序》对它的彻底改造亦研究不多,正是这些忽略阻碍了我们对其起源及演变的认识。到底是什么样的天才灵感使得孟子将一种倾听理解赋诗或引诗的方法转化成一个以读者为中心的复原式解释理论呢?汉代及以后的注《诗》、评《诗》家是怎样对这一理论加以运用的呢?文章力图对这两个重要问题作出粗浅的解答。     

气流干燥在制丝生产中的应用研究进展

综述了近年来国内烟丝气流干燥技术在工艺优化、设备改造及研发上的进展和气流干燥对烟丝物理特性、感官 质量及化学成分的影响,并与传统的滚筒烘丝工艺进行了对比。开发适合中式卷烟的烟丝气流干燥系统是今后研究的 重要方向。     

信息传输延迟与图的直径

本文主要运用图论的一些知识,解决信息传输延迟与图的直径的关系。通过对强连通有向图D和连通无向图G的分析论证,得出了直径的下界,并且在此基础由局域网推广为广域网,对G为连通无向图时进行推广,通过严格的证明得到了直径的下界,但所得不等式只是一个数学表达式图的直径大小的选择是相对的。如果要求网络中某两点的传输速度快,则直径越小越好;如果从源点发出一个信息要求网络中的客户都能收到,则直径越大越好。这样,图的直径就能直接反映点对点互连网络的传输延迟,在现实生活中具有很广泛的应用。     

Statistical issues in studying the relative importance of body mass index,waist circumference,waist hip ratio and waist stature ratio to predict type 2 diabetes

Systematic and appropriate statistical analysis is needed to examine the relative performance of anthropometrical indices, viz. body mass index (BMI), waist circumference (WC), waist hip ratio (WHR) and waist stature ratio (WSR) for predicting type 2 diabetes. Using information on socio-demographic, anthropometric and biochemical variables from 2148 males, we examined collinearity and non-linearity among the predictors before studying the association between anthropometric indices and type 2 diabetes. The variable involving in collinearity was removed from further analysis, and the relative importance of BMI, WC and WHR was examined by logistic regression analysis. To avoid non-interpretable odds ratios (ORs), cut point theory is used. Optimal cut points are derived and tested for significance. Multivariable fractional polynomial (MFP) algorithm is applied to reconcile non-linearity. As expected, WSR and WC were collinear with WHR and BMI. Since WSR was jointly as well as independently collinear, it was dropped from further analysis. The OR for WHR could not be interpreted meaningfully. Cut point theory was adopted. Deciles emerged as the optimal cut point. MFP recognized non-linearity effects on the outcome. Multicollinearity among the anthropometric indices was examined. Optimal cut points were identified and used to study the relative ORs. On the basis of the results of analysis, MFP is recommended to accommodate non-linearity among the predictors. WHR is relatively more important and significant than WC and BMI.     

关于实施结构性减税政策若干问题的分析

2011年中央经济工作会议提出,2012年我国要继续实施积极的财政政策。结构性减税政策在积极的财政政策中具有重要的地位和作用。近年来,我国实施的结构性减税政策具有多税种并用、多手段并举、多环节并促的特点,这一政策在减轻企业和居民税收负担、鼓励和扩大内需、引导经济结构战略性调整、保障和改善民生等方面产生了积极效应。从动态上看,减税政策对经济的刺激作用在一定程度上增强了经济活力,培育了新的税源,为国家继续实施积极的财政政策提供了可靠的财力保障。     

On the information content of partial observations

The modified zero order approach to estimating coefficients in the face of missing observations treats them as parameters to be estimated simultaneously with the missing observations. The paper then investigates (in the context of Han's generalized regression model)(i) when parameter estimators don't vary between using the partial data points and using only the complete ones (the informationless result), and (ii) large sample properties of the modified zero order estimator. It's found the sequential cut property is crucial to the informationless result for coefficient estimators; consistency of the modified zero order estimator depends on the percentage of observations with missing elements for large sample sizes or the sequential cut property.     

Augmenting a Submodular and Posi-modular Set Function by a Multigraph

Given a finite set V and a set function , we consider the problem of constructing an undirected multigraph G = (V,E) such that the cut function together has value at least 2 for all non-empty and proper subsets of V. If f is intersecting submodular and posi-modular, and satisfies the tripartite inequality, then we show that such a multigraph G with the minimum number of edges can be found in time, where is the time to compute the value of f(X) for a subset .     

A Tight Semidefinite Relaxation of the MAX CUT Problem

We obtain a tight semidefinite relaxation of the MAX CUT problem which improves several previous SDP relaxation in the literature. Not only is it a strict improvement over the SDP relaxation obtained by adding all the triangle inequalities to the well-known SDP relaxation, but also it satisfy Slater constraint qualification (strict feasibility).     

缝洞型底水油藏油井见水及含水规律实验研究

针对塔河碳酸盐岩缝洞型底水油藏的特点,根据矿场生产的动静态资料,利用相似理论,构建不同缝洞组合的可视化模型,开展物理模拟实验。比较和验证了不同含水上升规律所对应的储集空间类型,揭示了不同含水上升规律的物理本质,为此类油藏的合理开发提供了必要的实验和理论依据。实验证实,碳酸盐岩缝洞型底水油藏油井见水和含水上升规律存在5 种基本形态,而每一种类型都与特定的储集体地质特征、缝洞组合关系、水体能量的大小以及水体与储层的沟通程度密切相关;底水入侵的方式与砂岩油藏有很大区别,底水主要沿大裂缝窜进,溶洞内油水界面缓慢水平抬升,流体流动属于层流,这将简化管流与渗流耦合的数学模型。