A NEW APPROACH OF OPTIMIZATION

In this paper, a necessary optimality condition of problems with equality constraints is investigated by the implicit function theorem in n-dimensional Euclidean space. A new approach solving these problems is obtained. The number of dimensions of corresponding system of equations is less than the classic Lagrangian multiplier method.     

The Algorithm of Reduced Dimension forQuadratic Programming with Equality Constraints

In this paper,based on reference a method to solve the problem with equality constraints is given.A new approach for solving these problems is obtained,the number of dimensions of corresponding system or equations is less than that of the classic Lagrangian multiplier approximation.Using nonlinear equality constraints,the approximate algorithm is obtained.Moreover,the numerical difficulty is reduced by means of the new algorithm.     

Fast Algorithm About Unit Commitment Based on Revised BP Artificial Neural Network and Dynamic Search

In order to reduce the operation cost and optimize the unit commitment,the fast algorithm about unit commitment based on revised BP ANN(Artificial Neural Network) and dynamic search is discussed.The BP ANN is trained with Levenberg-Marquardt algorithm,which aiming at its drawback of the storage of some matrices that can be quite large for certain problems,and a revised algorithm is presented.The BP ANN is used to generate a pre-schedule according to the input load profile.Then the dynamic search is performed some stages where the commitment states of some of the units are not certain.The experimental results indicate that the proposed algorithm can reduce the execution time and memory space without degrading the quality of the generation schedule.     

THE APPLICATION OF NETWORK PROGRAMMING METHOD ON THE SHORT TERM OPTIMAL SCHEDULING FOR CASCADED HYDROPOWER STATIONS

The problem of the short term economic scheduling for cascaded hydropower stations is discussed with the network programming method. A new network model is built to dispatch the load to each unit when the unit commitment is determined. An algorithm of the minimal cost maximal flow is also discussed using the model and the algorithm to the Longxi River Cascaded Hydropower Stations, the computational result on the microcomputer VAX II shows that the model and the algorithm are correct and applicable.     

A Mixed Modelling Approach for Randomized Experiments with Repeated Measures

Repeated measurements on the same experimental unit are common in plant research. Due to lack of randomization and the serial ordering of observations on the same unit, such data give rise to correlations, which need to be accounted for in statistical analysis. Mixed modelling provides a flexible framework for this task. The present paper proposes a general method to formulate mixed models for designed experiments with repeated measurements. The approach is exemplified by way of several examples.     

山地城市热环境及其聚落特征的关联分析

以重庆主城区为研究对象,利用Landsat 8传感器OLI和TIRS获取的遥感影像为数据源,进行城市聚落特征包括地形特征、土地利用等与地表温度的差异性分析。结果表明：城市的热环境空间分布差异较大,海拔高度对温度的影响强于地形起伏度;（NDVI、NDBI、MNDWI等）和地表温度的相关关系呈分段线性关系;不同土地利用类型的热强度和热变异程度差异明显,建设用地的温度最高且斑块温度间的变异性最强,虽然水体的平均温度最低,但斑块温度间的变异性却较高;从格网分析的结果可以看出,格网内部水体的“冷岛效应”明显、建设用地的“热岛效应”显著,耕地与自然植被面积的增加使得各空间格网温度更趋向于稳定。     

Analysis on the Optimal Operation in Hydroelectric Station of Gezhouba

The optimal operation in hydroelectric station unit is me opumum problem,which include unit commitment,load distribution and unit maintenance. The authors research the optimal operation in units in hydroelectric station of Gezhouba by the genetic algorithm and dynamic programming to satisfy the demand of economic operation of Gezhouba. They arrange and organize the program of the units in r6ason to go for the better benefit and satisfies security, credibihty and high quality of electric production . These methods can work out the most optimum result. When the head of water and the flux is confirmed they can distribute the flux to the units to realize the optimal operation of the scheduling in Gezhotlba.     

A NEW ON LINE AND REAL TIME METHOD FOR DETERMINING HARMONIC AND REACTIVE CURRENTS

According to the basic idea of phasar analysis and by applying a special multiplier, a new on line and real time method is derived for determining harmonic current and reactive current of an electric network. This method has a good dynamic response characteristic and solves for the first time the determining problem for the compensation system in single phase system,which is also appliable to the three-phase system.     

Numerical Simulation of Natural Ventilation and Thermal Environment in Industrial Plant with Heat Source

Numerical simulation of typical industrial plant was conducted by computational fluid dynamics (CFD) method. The influences of distances between fresh air inlet and ground on thermal environment and distribution of pollutant concentration in working zone were discussed when the heat source intensity and pollutant source were fixed. The main features of industrial plant with heat source were analyzed. The air velocity in working zone and the radiation between the wall surfaces should be considered for comprehensive evaluation of the thermal environment of industrial plant. Heat stress index, HSI, was introduced as thermal index to evaluate the thermal environment. Results showed that lifted fresh air inlet was not only helpful to increase the ventilation rate and the air velocity which improve the thermal environment in working zone, but also to decrease the mean pollutant emission concentration in the plant. When the distances between fresh air inlet and ground increased, the ventilation rate and the air velocity in working zone increased and the HIS and pollutant concentration decreased. When the distances between fresh air inlet and ground exceeded 1.2 m, the ventilation rate and the air velocity in working zone tended to be constant.     

种茎对多花黄精产量和药用品质的影响

针对目前国内多花黄精种茎无标准和用种不规范的现状,研究多花黄精种茎规格、年龄对产量及药用品质的影响,旨在为多花黄精科学选种用种提供理论依据。采用双因素随机区组设计,主因素为规格,副因素为年龄,以多花黄精种茎的芽头数、茎长、茎径和茎质量为指标,采用K-means聚类法将种茎分成3个规格、3个年龄,通过调查出苗率、单株产量、单位面积产量和块茎多糖含量变化情况,分析不同规格、年龄种茎处理下2年生多花黄精产量和药用品质的差异。种茎规格、年龄与出苗率相关;种茎规格与单株产量、单位面积产量极显著相关,种茎年龄与单株产量、单位面积产量显著相关;种茎规格与多糖含量极显著相关,种茎年龄与多糖含量显著相关。推测种茎规格与年龄存在交互作用,高规格、低龄多花黄精种茎适宜作种,能显著提高多花黄精药材产量和药用品质。     

Full bridge LLC series resonant converter for X-Ray high voltage DC power supply

To prevent the duty cycle loss of full-bridge converter controlled by the phase-shifting method, a high frequency high voltage X-ray power supply is proposed. It combines full bridge LLC(FB-LLC) series resonant converter with bipolar single-phase symmetrical voltage multiplier. FB-LLC series resonant, high voltage transformer and bipolar single-phase symmetrical voltage multiplier are used in the main circuit. The LLC series resonant circuit and working conditions of soft switch are analyzed. The fundamental harmonic approximation model is established. The parameters of the main circuit are designed. The simulation results show that the output voltage adjusted continuously within 40~120 kV and without duty cycle loss. The X-ray power supply is proposed to achieve a quick rise and low ripple of output voltage. According to the simulation results, the proposed topology is correct and reliable.     

The equivalent enthalpy drop theory calculation of the ejector heaters applied for low-pressure feed water heater system of thermal power unit

There is much exergy loss in low-pressure feed water heater system of the thermal unit. The thermo-economic characters by the equivalent enthalpy drop method while the low-pressure heater was replaced with the ejector heater. At the same time, the thermo-economic characters formulas for the different factors were also gotten. Based on these results, the thermo-economic changing features were analyzed for the low pressure heaters replaced with the ejector heaters of the N600-165/535/535 units, and the results were compared with the normal heat balance method. The results show that the ejector heaters can reduce the exergy loss efficiently, and the thermo-economic effects is the best for replacing the all low-pressure heaters with the ejector heaters, and its efficiency can be increased by 0.263%. The given equations of this paper can be used for analyzing the thermal economic effects.     

Heterogeneity in the local employment multipliers in the United States

Recent studies have found evidence of a local employment multiplier’s effect. For the most part, these studies provide an average estimate for all labor markets. In this paper, we examine how the average local employment multiplier, the effect of an exogenous increase in employment in the tradable sector on total employment, depends on the characteristics of the local labor market. Specifically, we estimate the average multipliers for coastal, noncoastal, large, and small metropolitan statistical areas (MSAs) across different time periods using the data of 333 US MSAs. Overall, we find a reduced form of local employment multiplier ranging from 1.38 to 2.24, which is within the range of typically estimated local employment multipliers. In addition, the characteristics of the local labor market matter. The local multipliers appear larger in noncoastal and large MSAs. For small and coastal metros, the multiplier is closer to 1.5 than to 2.0 while in the case of large and noncoastal metros, it is closer to 2.0 than to 1.5. The local multipliers are also sensitive to the time period considered.     

Differences between spring wheat cultivars in early growth

Summary Twelve spring wheat cultivars were grown as isolated plants in the field and their pre-anthesis growth was interpreted in terms of plant growth analysis. Relative growth rate (RGR) decreased steadily with time due to a decline of leaf area per unit plant weight (LAR), which could be explained by the reduction of the portion of leaf weight in total plant weight (LWR). Growth per unit leaf area (NAR) and leaf area per unit leaf weight (SLA) changed only little with time.Differences between cultivars for NAR and LAR were of similar magnitude: both 8% when measured by the genetic coefficient of variation. Because both quantities were negatively correlated, the genetic variation of RGR was only 5%. Genetic variation for LWR and SLA were also of similar size, both about 4%. Estimates of genetic variances and covariances based on cultivar means appeared to be biased strongly when the error variation of the means was neglected.Special attention is paid to the methodology of plant growth analysis.     

Application of Symmetric Galerkin Boundary Element Method in Limit Analysis of Plane Problems

Based on Melan's theorem, the symmetric Galerkin boundary element method (SGBEM) is used to discretize two dimensional structures and a computational formulation of structural limit analysis is established. The self equilibrium stress field is constructed by linear combination of several basic vectors, which are the stress differences between different iteration steps at the same increment using the traditional elastoplastic incremental method. Then the complex method is used to solve the nonlinear programming directly, so that the lower bound load multiplier of two dimensional structures is obtained. The validation of the present method has been confirmed by some numerical examples.     

A RESEARCH OF THE INFLUNCE OF RARE-EARTH ELEMENT ON THE THERMAL FATIGUE BEHAVIOR OF CAST IRON

It is known that cylinder heads, exhaust manifoids, ingot molds, etc. are often failed resulting from thermal fatigue. For this reason, the influence of RE on the thermal fatigue behavior of cast iron was studied by measn of a thermal fatigue test unit with completely constrained strain developed by ourselves. The test results shown that RE can improve the thermal fatigue resistance of cast iron greatly when residual RE contents surpass a critical value. This value is 0.04-0.045% for light Rare-Earth, and 0.045-0.05%; for heavy Rare-Earth. Further more, the relationship between RE and the thermophysical and mechanical properties of cast iron which have influence on thermal fatigue resisteance was also discussed.     

The Key Parameters Method of Calculating Geothermal Heat Exchanger Length

The geothermal heat exchanger is the key component of ground coupled heat pump systems. We discuss the key parameters method of calculating geothermal heat exchanger length based on line source theory. Typical meteorological year data is used to determine the hottest month, the coldest month and annual average surface temperature. The building hourly load can be obtained by introducing the concept of equilibrium temperature. The cooling fraction and the heating fraction then can be calculated using building hourly load and performance parameters curve fit of a water source heat pump unit. The method for selecting the hottest and lowest entering fluid temperature and calculating the borehole and ground thermal resistance is given. A vertical U tube heat exchanger length calculation procedure is proposed.     

不同单位浓度营养液对岩棉培番茄营养生长的影响

以岩棉为栽培基质，研究了不同单位浓度营养液对番茄营养生长的影响。结果表明，在营养生长时期，１．０单位标准浓度营养液（ＥＣ２．５０ｍＳ／ｃｍ）较０．５单位标准浓度营养液（ＥＣ １．４０ｍＳ／ｃｍ）有利于番茄营养生长和地上部与根部干物质积累。营养液处理２８天后，浇以０．５单位标准浓度营养液的番茄植株根系发生褐变，逐步坏死。试验还表明，岩棉培番茄地上部与根部生长高度相关。     

Thermal Infrared Radiation for Assessing Crop Water Stress in Wheat

Field studies on differentially irrigated wheat ( Triticum aestivum L.) crops were conducted at Pantnagar for two years to evaluate the use of thermal infrared radiation to detect crop water stress. Data show that the stress-degree-day index (mid day canopy-air temperature difference) is influenced by environmental variability other than soil moisture. Improvement in the stress-degree-day (SDD) index was achieved by including the measurements of vapor pressure deficit and approach was termed as plant water stress index (PWSI). Observations indicated that daily variation in SDD values due to meteorological changes was removed through PWSI. Better correlation was found between soil-induced leaf water potential and plant water stress index than between total leaf water potential and plant water stress index. It is concluded that remote sensing of thermal infrared radiation offers a promising technique which can be incorporated into irrigation management programme.     

云南稻-鸭共生模式效益的研究及综合评价（三）

通过不同放鸭只数的试验,研究了在中高产田单位面积放鸭的数量与产量构成因素和病虫草害发生的关系,分析了产量构成,病虫草害发生的情况,为稻－鸭共生模式技术的推广提供理论依据。