基于风景园林信息模型(LIM)的山地 景观地形参数化设计实验研究——以 Civil 3D和InfraWorks交互设计为例

缺乏参数关联与控制的山地设计在科学性与精准性 上出现诸多设计障碍,如山地场地、道路等三维设计信息与二 维设计不匹配;山地曲线、曲面地形要素设计精度不高等。 借鉴BIM技术在建筑参数化设计中的应用,探索Civil 3D与 InfraWorks协同处理山地地形并进行信息交互的设计方法, 完成山地地形三维模型设计与二维设计的参数关联,从而优化 山地设计程序,提高山地设计精细化程度,并为设计者即时提 供设计反馈信息和设计变更途径。通过研究实现山地景观信息 在BIM平台中的集成应用,构建基于风景园林信息模型(LIM) 的山地设计路径,为山地地形设计提供参数化解决方案。     

A fast and efficient load flow technique for unbalanced distribution system

This paper presents a fast and efficient load flow technique for unbalanced distribution system. The proposed load flow technique is derived by promulgating the concept of conventional backward forward sweep (BFS) technique of power flow study for distribution system. The proposed technique employs a novel load-impedance matrix (LIM) to calculate the bus voltages in a single step unlike the conventional BFS approach which involves two separate steps (backward sweep and forward sweep) to perform the same and this improvement is claimed as the novelty of this work. This distinctive feature makes the proposed algorithm faster in operation. Nodal voltages, at any iteration, may be calculated, directly, from the values obtained in the previous iteration by utilizing LIM. A simple concept of set theory is adopted here to construct the LIM. Special treatments are also included in this method to analyze weakly meshed systems. The proposed technique is flexible enough to accommodate any sort of changes in the existing network topology through LIM. It is tested on different three-phase balanced and unbalanced radial distribution systems as well as weakly meshed networks for load flow study. A separate case study is also presented to check the validity of the proposed load flow technique for various transformer connections. The obtained results demonstrate the effectiveness of the proposed technique. Furthermore, performance comparison reveals that the proposed algorithm is, computationally, faster and robust than the conventional power flow techniques reported in the recent state-of-the-art literatures.     

大功率直线感应电动机推力脉动研究

直线电机边端效应是由定子铁心、次级开断所致的固有效应,该效应会引起电机电磁推力的不同频率的脉动。本文首先基于电磁推力公式对边端效应所致的推力脉动频率进行了理论分析。然后利用一维磁路法对动态纵向边端效应引起的次级感应涡流沿轴向的分布规律进行了理论分析和解析计算,根据次级感应涡流进而计算得到了动态纵向边端效应引起的转差频率两倍频推力脉动幅值的解析表达式,并得到了推力脉动幅值和不考虑边端效应时的电磁推力值的比例关系,最后通过峰值功率20 MW,最大出力900 k N的大功率直线感应电动机实验系统对分析结论进行了试验验证。理论分析和试验结果表明:计及边端效应时直线电机电磁推力存在供电频率两倍频和转差频率两倍频的脉动,其中转差频率两倍频的脉动由动态纵向边端效应导致,主要和次级极数以及转差频率有关。     

曲线地段直线电机轮轨列车动力学响应

为研究直线电机轮轨列车行驶于曲线段线路上时,铁路线路条件对列车动力响应的影响规律,以便为修改线路设计规范提供理论依据.建立直线电机轮轨交通列车线路动力学模型,模型中直线电机所受垂向电磁力大小随列车牵引速度和电机气隙的变化而时刻改变.仿真模拟并分析垂向电磁力、车速、曲线半径、超高、轨道不平顺对系统动力响应的影响.结果表明:轨道垂向不平顺和高车速对气隙影响显著;列车通过小半径曲线段时,垂向电磁力对脱轨系数和轮重减载率的消减作用显著;脱轨系数、轮重减载率、轮轨横向力、车体横向加速度、车体横向位移这5类动力响应的最大值,同时受车速、曲线半径、超高影响显著.基于5类动力响应最大值的拟合公式,可对车速、曲线半径、超高取值范围进行合理匹配,并确定曲线地段的合理车辆限界.     

网格型复合次级直线电机的分析

本文提出适合驱动带式输送机的网格型复合次级直线电机。通过建立回路微分方程组,以矩阵法分析直线电机起动时的性能。理论分析与实践结果吻合。     

Modeling and Simulation for Transient Thermal Analyses Using a Voltage-in-Current Latency Insertion Method

This article presents a modeling and simulation method for transient thermal analyses of integrated circuits (ICs) using the original and voltage-in-current (VinC) latency insertion method (LIM). LIM-based algorithms are a set of fast transient simulation methods that solve electrical circuits in a leapfrog updating manner without relying on large matrix operations used in conventional Simulation Program with Integrated Circuit Emphasis (SPICE)-based methods which can significantly slow down the solution process. The conversion from the thermal to electrical model is performed first by using the analogy between heat and electrical conduction. Since electrical inductance has no thermal equivalence, a modified VinC LIM formulation is presented which removes the requirement of the insertion of fictitious inductors. Numerical examples are presented, which show that the modified VinC LIM formulation outperforms the basic LIM formulation, in terms of both stability and accuracy in the transient thermal simulation of ICs.     

一种利用压强脉动信号测取鼓泡床中气含率的新方法

实验测定了不同操作条件下反应器内的压强脉动时序信号. 提出了一种求取鼓泡床中气含率的新方法，即根据压强脉动信号功率谱图上的主频确定小波主尺度，并对该尺度上的细节信号的间歇行为进行了分析；在局部间歇性分析(Local Intermittency Measurement, LIM)曲线上选取合适的阈值后，对不同径向位置上的局部气含率进行估计，进而得到反应器截面上的平均气含率值. 根据本工作的LIM分析方法计算得到的气含率与压降法实测气含率相一致，这也表明反应器内气泡是导致鼓泡流中压强脉动的主要因素.     

Analysis of 41 kb of the DNA sequence from the right arm of chromosome II of Schizosaccharomyces pombe

We report the complete sequence of cosmid c18A7 (41 046 bp insert), located on the right arm of chromosome II of the Schizosaccharomyces pombe genome. The sequence, which partially overlaps with cosmids SPBC4F6 and SPBC336, contains 16 open reading frames (ORFs) capable of coding for proteins of at least 100 amino acid residues in length (one partial) and one small nucleolar RNA (snoRNA). Four known genes were found: swi10 (encoding a mating-type switching protein also involved in nucleotide excision repair); dim1 (encoding a dimethyladenosine transferase); arf1 (encoding ADP-ribosylation factor 1); and pol3 (cdc6) the partial fragment, encoding the 125 kDa catalytic subunit of the DNA polymerase type B. Six ORFs similar to known proteins were found. They include a transporter of the major facilitator superfamily class, a vacuolar sorting protein, an asparagine synthase, a nuclear protein, a reticulum oxidoreductin and a heat shock protein. Each protein product of the other six ORFs has conserved domains and can be assigned a molecular, but not a biological, function. The sequence has been submitted to the EMBL database under Accession No. AL080287.     

高温超导直线感应电机的优化设计

详细讨论了高温超导直线感应电机的结构设计和初级绕组排列方式,给出了高温超导带材临界电流和背景磁场的关系曲线。采用Maxwell有限元电磁分析软件对高温超导直线感应电机进行了详细的电磁分析,并对初级绕组匝数、初级铁心槽高和初级铁心槽宽等关键参数进行了参数扫描和优化,分析了它们对电机电磁力、初级槽漏磁通和电机临界电流的影响,提出了高温超导直线感应电机的优化设计方法。根据得到的高温超导直线感应电机优化设计参数制造了一台完全相同的铜绕组实验样机,测试了样机在不同电流和速度下的推力,对比相同条件下得到的有限元电磁仿真结果,可以得到一个修正推力仿真结果的系数,这个系数对研究不同电机参数的电机推力很有意义。     

成都独角兽岛启动区景观设计LIM实

通过介绍成都独角兽岛启动区的设计和施工建造过程, 结合项目实际情况,有选择性地在风景园林设计的不同阶段,利 用相对的数字化信息模型技术来阐述和分析设计行业信息模型在 风景园林空间设计上的项目管理、设计技术、合作对接、质量把 控及施工建造等方面的实践经验。以此为例,探讨在行业中的实 践现状和发展风景园林信息模型(LIM)的必要性。