泵站前池单排方柱整流措施数值模拟

为改善泵站前池内水流流态,基于Fluent软件,运用RNG k-ε模型对加单排方柱的正向进水泵站前池流态进行数值模拟,分析单排方柱的几何参数对前池流态改善的影响。结果表明:单排方柱具有分流效果,流经单排方柱的水流会向前池两侧分散,在单排方柱的后方形成漩涡。无整流措施时,泵站前池流态紊乱;通过在前池加设单排方柱可显著改善流态;单排方柱宜布置在前池前中部,不宜布置在两侧回流区内;方柱宽度越小,分流作用越小,行近流速分布越不均匀。     

The effects of pause software on the temporal characteristics of computer use

The study investigated the natural work–pause pattern of computer users and the possible effects of imposing pause regimes on this pattern. Hereto, the precise timing of computer events was recorded across a large number of days. It was found that the distribution of the pause durations was extremely skewed and that pauses with twice the duration are twice less likely to occur. The effects of imposing pause regimes were studied by performing a simulation of commercially available pause software. It was found that depending on the duration of the introduced pause, the software added 25–57% of the pauses taken naturally. Analysis of the timing of the introduced pauses revealed that a large number of spontaneous pauses were taken close to the inserted pause. Considering the disappointing results of studies investigating the effects of introducing (active) pauses during computer work, this study has cast doubt on the usefulness of introducing short duration pauses.     

A GENERAL APPROACH TO THE STUDY OF SPATIAL SYSTEMS II. Two Examples of Application

The emphasis in this work is on the practical application of ideas set forth in Part I. Two studies involving spatial distribution are discussed: the distribution of human population in the Indianapolis, Indiana Region, and the world distribution of mammals. In the first, populations over the period 1890–1980 of Ihe 393 townships making up the study area are used to produce classifications involving various numbers of classes of township types. A test of the theoretical structure posed in Part I is then detailed. On the theory that the underlying relations involved cannot sustain a real world structure involving more than five functional classes, it is hypothesized that classifications involving more than five classes will be associated with township distribution patterns that conflict with Central Place Theory. This is shown to be clearly so. In the second study, the derivation of a five region partitioning of world mammalian distribution patterns is described. Discussion includes the introduction of a wholly new rationale for taxonomic revision based on biogeographic criteria (and ultimately the principles described in Part I). The study closes with a short argument regarding why the model described in Part I should not be labelled as either social physics or anti-humanistic.     

大战略、大平台、大作为——论西部国家级新区发展对新型城镇化的作用

通过对中规院主持的两江、天府、兰州和贵安等西部国家级(准国家级)新区的前期研究、规划设计和后续实施咨询服务等工作,以及新区相应所在省(直辖市)的省域城镇体系规划的规划编制工作的总结,从实证的角度出发,提出西部国家级(准国家级)新区的设立不是东部先发地区的翻版,而是国家从战略高度给西部发展提供平台,使西部地区发挥国家层面应有作用.     

An optimization method to find the thermodynamic limit on enhancement of solar thermal decomposition of methane

An optimization approach to enhancing the solar thermal decomposition of methane (TDM) reaction process based on the fluid flow pattern reconstruction is proposed. The sum of entropy generations due to TDM reaction and heat convection in the process is shown to tend to its maximum when the performance of the reaction is enhanced, and thus, is used as the criterial to optimize the velocity field of the fluid. This optimization problem is solved by the calculus of variations method. The obtained flow pattern is shown to be able to give the conditions to achieve the optimally enhanced TDM process. As the sum of the entropy generations tends to its extremum, the solution found by the optimization can be known as the thermodynamic limit for the TDM process enhancement. The obtained flow pattern can then be used to inspire the design of internal structures of the solar TDM reactor.     

Automatic generation control of a multi-area system using ant lion optimizer algorithm based PID plus second order derivative controller

This article presents the automatic generation control of an unequal three area thermal system. Single stage reheat turbines and generation rate constraints of 3%/min are considered in each control area. Controllers such as Integral (I), Proportional – Integral (PI), Proportional – Integral – Derivative (PID), and Proportional – Integral – Derivative Plus Second Order Derivative (PID + DD) are treated as secondary controllers separately. A nature inspired optimization technique called Ant Lion Optimizer (ALO) algorithm is used for simultaneous optimization of the controller gains. Comparison of dynamic responses of frequencies and tie line powers corresponding to ALO optimized I, PI, PID and PID + DD controller reveal the better performance of PID + DD controller in terms of lesser settling time, peak overshoots as well as reduced oscillations. Robustness of the optimum gains of best controller obtained at nominal conditions is evaluated using sensitivity analysis. Analysis exposed that the optimum PID + DD controller gains obtained at nominal are robust and not necessary to reset again for changes in loading, parameter like inertia constant (H), size and position of disturbance. Furthermore, the performance of PID + DD controller is found better as compared to PID controller against random loading pattern condition.     

SDF classifier revisited

This paper is addressing problems related to the construction of classifiers based on the Similarity Discriminant Function (SDF), in which the traditional vector representation of a pattern is replaced with matrix data. We introduce potential modifications of the matrix data structure and propose new variants of the SDF. The algorithms that we present were tested on images of handwritten digits and on photographs of human faces, taken from the ORL and CMU‐PIE databases. The results of experiments show that our modifications significantly improved the performance of the original SDF classifier.     

客家传统服饰刺绣图案

 从客家服饰刺绣图案的分类、刺绣技法、图案构成、色彩运用角度入手，总结出客家传统服饰刺绣图案按其表现题材可分为动植物、几何图纹、人物、文字、生活器物等五大类；刺绣技法分为七大系列二十七种针法；图案构成以边缘式、主题式与对称式为主；服饰图案色彩对比强烈、具有尚“俗”审美情趣且倾向装饰功利性。得出客家传统服饰图案在构图、表现题材、技法、用色等方面呈现地域性特征，并且具有深沉的中原汉民族审美情感倾向。