Prediction of the Economic Development for the Circumjacent Reservoir Region of the Longtan Hydropower Project Using Grey Quantitative Analog     

Duan Yurong Zhu Jinming Liu Size Hong Guiyu 《保鲜与加工》1996,(5):95-99

In order to overcome some technical difficulties,we adopt ingenously the grey models combined with the quantitative analog method,and select the Dan Jiangkou Project which has accumulated practical operation data for a long time as the analog project to predict the economic influence for the circumjacent reservoir region of the Longtan hydropower project.On the basis of analog we have built various industrial economic grey models,and compare them with the corresponding predictions for the unconstructed reservoir case.The predictions of the former are greatly larger than the later ones.and hence provides a certain scientific basis for the central leaders to make a decision for constructing the huge hydropower project ultimateiy.  相似文献   

The Feasible Control for the Day-operation of the Three-Gorge Cascade Hydropower Station     

Duan Yurong  Fu Li 《保鲜与加工》1995,(1):19-26

The feasible control problem is presented for the day-operation of the Three-Gorge Caseade Hydropower Station. The significance of the problem is explained. Basic propetties ofthe problem and the approaches to study it are discussed. Two methfods are given for solving theproblem. which are calculus of variation and linear programming. In the former. the Euler equationwith time-lag and the generalised two-point boundary conditions are obtained and the correspondingpractical implication is interpreted. In the latter. the rationality for the discrete model is exptainedand the computalional details are given for the implement software. some questions which should bepaid much attentfon and the corresponding propeels are prasented based on the numerical results andtheoretical analysis  相似文献   

Vector form intrinsic finite element analysis based on fine beam model     

Chen Chong  Yuan Xingfei  Duan Yuanfeng  Qian Ruojun 《保鲜与加工》2015,(2):1-7

精细梁不同于Euler梁和Timoshenko梁,该模型在考虑剪切变形的同时还考虑了横向弯曲时截面转动产生的附加轴向位移及横向剪切变形影响截面抗弯刚度后产生的附加横向位移。推导了适用于向量式有限元分析的精细梁单元应变和内力表达式,采用FORTRAN自编了向量式有限元程序。对悬臂梁、两端固支梁和门式框架进行了算例分析,对比了采用不同梁单元模型下结构的竖向位移。结果表明：当高跨比较小时,3种梁单元的竖向位移相差不大;当高跨比较大时,精细梁单元的竖向位移较Euler梁和Timoshenko梁明显增大,表明剪切变形及刚度折减引起的附加轴向位移、附加横向位移不能忽略。精细梁单元模型对高跨比较大的梁进行分析可望得到更精确的结果。  相似文献   

Management System of the Tender and Bidding for Power Projects with a Valuation Based on the Bill of Quantities     

CAO Duan  LIU Zhen  SU Zeng-de 《保鲜与加工》2007,(1):155-158

Valuation based on the bill of quantifies will change the existing valuation mode of tender and bidding. For the standardized management of tender and bidding for power projects and the inteUigentized information management of power enterprises, it is an inevitable trend of reform to apply the valuation mode based on the bill of quantifies. According to the characteristics of power projects, this paper expounds the working process of the valuation mode based on the bill of quantities and analyzes the goal and function need of the tender and bidding management system. Considering the calculation procedure of the valuation and the quote strategy of quantities bill, the composition of fees for the valuation is settled and the calculation method is designed. To establish the management system of tender and bidding with a valuation based on the bill of quantities is beneficial for the costing reform of power projects and the perfection of the tender and bidding market. Therefore it is of great significance to spread the new management mode of project costing with a valuation based on the bill of quantities.  相似文献   

APPLICATION OF DECOMPOSITION COORDINATION METHOD OF LARGE - SCALE SYSTEMS AND METHOD OF NONLINEAR PROGRAMMING TO ECONOMIC SCHEDULING OF POWER SYSTEM     

Duan Yurong Tian Yufang 《保鲜与加工》1992,(6):112-118

In this paper,we discuss a mathematical mode) for optimization of active power dispatch of large-scale hydro-thermal power systems with cascaded hydropower stations. The following factors are taken into account: the variation of the head in the hydropower stations, water transport delay between cascaded stations etc. Using the decomposition-coordination method of large scale systems, we obtain a three-layer-hierarchical coordination system and a three-layer-hierarchical computational structure. We also discuss the computational methods which are used by each hierarchy. We have taken a test computation and analysing the result of an actual hydrothermal power system. The computational results show that it may obtain a satisfactory economic benefit. The paper provides some research work on the economic scheduling of hydrothermal power systems by the decomposition-coordination method of large-scale systems,multiplier method and a new variable metric method.  相似文献   

TRUST REGION METHOD FOR UNCONSTRAINED OPTIMIZATION     

Tang Jian Duan Yurong 《保鲜与加工》1991,(1):33-41

A new trust region algorithm is proposed for solving unconstrained optimization problems. According to the quadratic approximate model of the original optimization problem,the trust region algorithm uses directions,a convex combination of the quasi-newton direction and the steepest descent direction. This algorithm with new strategy is analyzed and the global and local quadratic convergent theorems are proved. At last,the implementation and computational results of the algorithm are demonstrated.  相似文献   

高产优质商品玉米生产模式：—三种遗传效应集成利用（TEU）   总被引：3，自引：0，他引：3  

段民孝  宋同明等 《种子》2001,(2):3-6

通过大量详实资料，对玉米杂种优势、雄性不育，油分基因花粉直感等3种遗传效应的研究现状作了详细概述，根据相关的遗传理论与实践，提出了将三种遗传效应进行技术集成的可能性，从而形成一种高产高油玉米生产模式，有可能是未来玉米生产的发展方向。  相似文献   

不同光照条件下番茄主要性状的变化及相关分析   总被引：5，自引：1，他引：5  

毛秀杰  王巨媛  孙铭  潘玉霞  孙中峰 《中国农学通报》2006,22(12):95-95

耐弱光性不同的番茄品种（品系）对光照条件反应不同，确定番茄耐弱光鉴定指标，可以快速有效地从大量种质资源中筛选耐弱光的番茄品种，提高品种耐弱光选择效率；试验对耐弱光性不同的4份番茄品种（品系）于定植后进行遮光处理，分别研究各品种在不同光照下的光合特性、经济性状的变化，并对11个性状进行相关及通径分析。试验结果表明，在透光率为25%（平均光照强度的光通量约为230μmol/）的光照条件下，净光合速率、气孔导度、蒸腾速率、坐果率、单果重、单株产量均有不同程度的下降，且弱光下坐果率、弱光下净光合速率、弱光下胞间CO2浓度与相对单株产量直接通径系数分别为1.92、1.76、2.13，相关系数分别为0.53、-0.09、0.48。可见，弱光下的坐果率是鉴定番茄耐弱光性的可靠指标，弱光下净光合速率和胞间CO2浓度可作为耐弱光性鉴定的重要辅助指标。  相似文献   

软儿梨冷冻贮藏过程酚类物质与多酚氧化酶的区域化分布     

段瑞君  郑淑霞  王振辉  熊辉岩 《中国农学通报》2015,31(32):72-75

为研究冷冻贮藏中不同部位酚类物质和多酚氧化酶的分布特征,以青海省地方梨优良品种‘软儿梨’果实为研究材料,采用高效液相色谱法和比色法测定软儿梨果实后熟(室温)、冻藏(-18℃)和解冻(室温)3个时期的果皮、果肉中总多酚、绿原酸的含量和多酚氧化酶活性。结果表明:软儿梨果实后熟后,酚类物质果肉?果皮,多酚氧化酶则果皮?果肉;冷冻贮藏过程中,不同部位的酚类物质和多酚氧化酶均呈现不同程度的升高,但绿原酸在果皮急剧下降、果肉中略有增加。解冻后总体呈下降趋势,2个部位总酚、多酚氧化酶下降明显,而果皮中的绿原酸变化不大。研究表明:软儿梨果实后熟后,酚类物质和多酚氧化酶分布呈现区域化,冷冻贮藏加剧了酚类物质和多酚氧化酶活性的积累,导致了软儿梨冷冻贮藏后果皮先于果肉发生了褐变。  相似文献   

果胶酶降解壳聚糖工艺优化及特性动态变化分析     

李和生  孙玉喜  王鸿飞 《农业机械学报》2006,37(1):83-86

通过正交试验对果胶酶水解壳聚糖的工艺进行优化，并对降解过程中粘度、还原糖生成量、平均分子量等指标的动态变化进行研究。结果表明，果胶酶在50℃、pH值4．5、酶用量与壳聚糖质量之比为3、壳聚糖脱乙酰度为80％时对壳聚糖降解效果最佳，其中底物脱乙酰度对酶解效果影响极显著。在最适条件下，果胶酶对壳聚糖水解约1h，可控制产物平均分子量在2500左右。果胶酶降解壳聚糖的起始速度非常快，反应30min后粘度下降基本平稳；水解反应进行135min后，产物还原糖生成量逐渐趋于平稳。  相似文献