水氮耦合供应对温室番茄果实硝酸盐累积的影响

采用2水平灌水量(W1:4541.0、W2:2270.6 m3/hm2)×3水平氮肥追施量(N1:747.4、N2:373.7及N3:0 kg/hm2),研究了不同灌溉、施氮量对日光温室番茄果实硝酸盐累积的影响。结果表明,番茄果实硝酸盐含量随果实成熟度的提高而降低、随结果部位的提高而提高。水氮耦合供应可以显著影响番茄果实中硝酸盐含量。在施氮量相同的情况下,果实硝酸盐含量随着灌水量的增加而降低;而在灌水量相同的情况下,果实硝酸盐含量随施氮量的增加而增加。     

基于MATLAB的热能动力机械测控技术课程教学方法研究

文章主要是针对我校热能与动力工程专业学生学习测控技术课程过程中遇到的问题进行了探讨。结合MATLAB软件数值计算和图形处理功能,不断改进教学方法和手段。将MATLAB软件应用于热能动力机械测控技术课程理论与实践教学,不仅提高了学生学习主动性和积极性,而且培养了学生的创新能力,逻辑思维能力,以及工程应用能力。     

An Improved Method of the Transient Waveform Analysis in Power Systems

The angular frequency and decaying constant of each copmonect for the transient waveform in power systems were obtained by using the discrete Fourier transform; the amplitude and phase angle were calculated in the linear curve fitting method. And all of the parameters obtained above were treated in an unified optimization by using the curve fitting optimization of the least square method of general nonlinear funcrion so as to get the results of waveform analysis. Two examples are included.     

Automatic Measuring Method of Eyeglass Lens Power

A method of measuring eyeglass lens power is proposed. A position detector and 3 beams of ray are used to measure the prismatic, spherical and astigmatic powers. Based on the method, an automatic focimeter with simple structure can be developed. The measure errors of prismatic and spherical powers are analyzed, from which it is concluded that the precision of the position detector is the key to the method.     

THE PRINCIPLE OF COMPILING CITY WATER SUPPLY HYDROGEOLOGICAL MAPS AND THE DISCUSSION OF ITS METHOD

On the basis of outlining our present situation of city water supply and itsgeological map compilation,this paper suggests a new principle which should befollowed in the compiling work of city water supply hydrogeological maps and themain contents of compilation and the ways of expression as one of the map com-piliing plans to be discussed in this field.     

Transmission Congestion Management Based on Power Influence Coefficient

Basing eliminating on the idea that the generator who has the most influence on the power flow of line is mostly in favor of transmission congestion, the model of congestion management with the object of minimizing adjustments of bufions varied with generation outputs is proposed. It can eliminate the congestion effectively by judging the generators who should be adjusted and the amounts of adjustment. The test on IEEE-RTS24 buses system and other practical systems show that the proposed method is effective.     

A Vovel Constracture of Combinatorial Knowledge Base for the Expert System of Eletrical Switching

By comparing the techniges of the production and the logic predicate for knowledge representation, this paper presents a kind of constructure of combinatorial knowledge base applied to the expert system for switch operation in electric power system . This constructure of knowledge base to be expanded and revised easily,and it is cinvenitnt to build the general shell of the expert system.     

A HIERARCHICAL CONTROL METHOD FOR REACTIVE POWER OPTIMIZATION IN LARGE-SCALED INTERCONNECTED POWER SYSTEMS

This paper presents a new hierarchical and coordinative control method for reactive power optimization in large-scale interconnected power systems. It combines the interconnection forecast method for hierarchical control in large-scale steady state industrial systems with the incremental linear programming method for reactive power optimization in real time. The results of applying the method to power system examples show that the method not only solves the problem of high dimension in order, but also keeps the advantages of the incremental linear programming method. The proposed method is also suitable for the security analysis of reactive power correction in large-scale interconnected power systems.     

A Spot Price Model with Var Cost

This paper has applied the var cost to the theory of spot price.An augmented Lagrange method is employed to develop the exact model of spot price of active power and reactive power,and the physical means of Lagrange multipliers are explained.The numerical examples are given to demonstrate the validity of the proposed model.