给水管网平差环方程法的改进

应用图论理论 ,对给水管网平差环方程法进行分析 ,给出了连续性方程的显式表达式 ,与能量方程构成了改进方法的基本方程 .线性化后采用高斯 -赛德尔法求解 .而对能量方程作不同简化可得到Hardy Cross法及其他算法 .此方法简单 ,计算量小 ,且准备工作有条理 。

平面复合连杆机构设计及可动性分析

由于设计尺寸不合理,复合机构在工作过程中产生奇异导致机构失效,因此在复合机构的设计过程中可动性分析是必要的环节;大量的研究成果是针对平面铰链机构的分析设计,而平面复合机构的研究工作相对较少。通过解析法推导出曲柄滑块机构曲柄和连杆的解析式以及通过矢量环方程法推导出五杆滑块机构杆长解析式,并将曲柄滑块机构和五杆滑块机构装配,对装配后的复合机构进行可动性分析,得到复合机构的杆长关系。为快速、准确的设计此类复合机构提供了一种新的方法。

Integrable Properties Associated with a Discrete Three-by-Three Matrix Spectral Problem

Based on a new discrete three-by-three matrix spectral problem, a hierarchy of integrable lattice equations with three potentials is proposed through discrete zero-curvature representation, and the resulting integrable lattice equation reduces to the classical Toda lattice equation. It is shown that the hierarchy possesses a HamiItonian structure and a hereditary recursion operator. Finally, infinitely many conservation laws of corresponding lattice systems are obtained by a direct way.

Application of Snapback Chronometry Method in Calculation of Regulation

Work study is an area of construction production rationalization in which with scientific, logical, holistic and system analysis methods of the process we gain optimum in way of work and time of work. Chronometry method is one of the work study methods which is appropriate for recording shorter cyclic processes and is based on statistical sampling theory. Determination of cyclic times and work performances of standard cyclic construction machines （SCCM） is one of key assumptions of dynamic planning of machine work on every construction site. Calculation methods of SCCM work performances arc one of basic research objects in the field of construction organization and technology. Study shows applied chronometry method in work of standard cyclic construction machine. Goal of this study is to accomplish regulation through measured time cycle and compare measured effects with effects obtained with standard methodology of calculating hydraulic excavator practical achievement for gaining regulation in order to determine main reasons which effect work performance on site.

An Integrated Approach to Oscillation Propagation Identification and Source Locating in Process Multi-loop Systems

An integrated method for identifying the propagation of multi-loop process oscillations and their source location is proposed in this paper. Oscillatory process loop variables are automatically selected based on the component-related ratio index and a mixing matrix, both of which are obtained in data preprocessing by spectral independent component analysis. The complex causality among oscillatory process variables is then revealed by Granger causality test and is visualized in the form of causality diagram. The simplification of causal connectivity in the diagram is performed according to the understanding of process knowledge and the final simplest causality diagram, which represents the main oscillation propagation paths, is achieved by the automated cutting-off thresh-old search, with which less significant causality pathways are filtered out. The source of the oscillation disturbance can be identified intuitively through the final causality diagram. Both simulated and real plant data tests are presented to demonstrate the effectiveness and feasibility of the proposed method.

Solving Dirac Equation with New Ring-Shaped Non-Spherical Harmonic Oscillator Potential

A new ring-shaped non-harmonic oscillator potential is proposed. The precise bound solution of Dirac equation with the potential is gained when the scalar potential is equal to the vector potential. The angular equation and radial equation are obtained through the variable separation method. The results indicate that the normalized angle wave function can be expressed with the generalized associated-Legendre polynomial, and the normalized radial wave function can be expressed with confluent hypergeometric function. And then the precise energy spectrum equations are obtained. The ground state and several low excited states of the system are solved. And those results are compared with the non-relativistic effect energy level in Phys. Lett. A 340 （2005） 94. The positive energy states of system are discussed and the conclusions are made properly.

Approach for Local Multi-Domain Cognition in Cognitive Network

During the evolution from cognitive radio to cognitive networks,the environment cognition extended from wireless environments to network and user environments.To understand the basic theory of Local Multi-Domain Cognition(LMDC),and to provide a theoretical basis for further study in cooperative multi-domain cognition and initiative multi-domain cognition,the LMDC is investigated in this paper.A Local Single-Domain Cognitive(LSDC)approach is first proposed based on multidimensional edge detection theory.This approach can divide the parameter space that describes the single-domain environment into different areas,and can represent each area with an identifier.Using this as a foundation,the single-domain environment is extended to multi-domain environments,and an LMDC approach is presented to describe the LMDC environment.The paper concludes by introducing two examples and the corresponding analysis to illustrate the feasibility of the proposed LMDC approach.

Appeal of 3 ＋ 4 Program： Good Students are Few but Growing at Secondary Vocational Schools in Shanghai

Secondary vocational education in Shanghai continues to experiment in an attempt to find ways to solve the decline of student enrollment and adjust to rapidly changing social and economic environments. The 3 ＋ 4 Pilot Program （three-year secondary vocational education and four-year undergraduate education） has been under experiment since 2014. It has attracted more and more academically good junior middle school graduates to secondary vocational schools with the national and local favorable policies and laws. Except the three-year’s hand-on practice, what appeals most to the junior middle school graduates is the academic transfer under the Program, a breakthrough in history of vocation education in China. However, only initiating a new program is not enough. Shanghai government should map out a long-term plan to set up promotion to increase the public awareness to change the long prevailing outdated ideology in order to add more to its appeal of the Program. There is still much work to be done before expanding the scope of the Program.

The structure of quadratic groups over commutative rings

Let （R, A） be a commutative form ring. We obtain a complete description of all subgroups of quadratic groups Q2n（R, A） which are normalized by elementary subgroups by form ideals, rather than usual ideals. For the weak sandwich theorem, we give a direct proof without using localization method.

Study and verification on dispersion coefficient in wave field

Transport and diffusion caused by coastal waves have different characteristics from those induced by flows. Through solving the vertical diffusion equation by an analytic method, this paper infers a theoretical formula of dispersion coefficient under the combined action of current and waves. It divides the general dispersion coefficient into six parts, including coefficients due to tidal current, Stokes drift, wave oscillation and interaction among them. It draws a conclusion that the contribution of dispersive effect induced by coastal waves is mainly produced by Stokes drift, while the contributions to time-averaged dispersion coefficient due to wave orbital motion and interaction between current and waves are very small. The results without tidal current are in agreement with the numerical and experimental results, which proves the correctness of the theoretical derivation. This paper introduces the variation characteristics of both the time-averaged and oscillating dispersion coefficients versus relative water depth, and demonstrates the physical implications of the oscillating mixing coefficient due to waves. We also apply the results to the costal vertical circulation and give its characteristics compared to Stokes drift.

Modeling of Focused Acoustic Field of a Concave Multi-annular Phased Array Using Spheroidal Beam Equation

A theoretical model of focused acoustic field for a multi-annular phased array on concave spherical surface is proposed. In this model, the source boundary conditions of the spheroidal beam equation （SBE） for multi-annular phased elements are studied. Acoustic field calculated by the dynamic focusing model of SBE is compared with numerical results of the O＇Neil and Khokhlov-Zabolotskaya-Kuznetsov （KZK） model, respectively. Axia/dynamic focusing and the harmonic effects are presented. The results demonstrate that the dynamic focusing model of SBE is good valid for a concave multi-annular phased array with a large aperture angle in the linear or nonlinear field.