Study on the Comparison of Different Methods of Simplifying Capacity Spectrum

It is necessary to simplify the capacity spectrum into bilinear form so as to get characteristic point of hysteretic bone curve(especially the yield point and the yielded stiffness),ductility and equivalent damping of the structure.Three general methods of calculating yield point and yielded stiffness of equivalent SDOF are introduced and the yield point and the yielded stiffness of three frame structures are compared using above given methods in this paper.The hysteretic bone curves of equivalent SDOF are decided by the equivalent yield force and displacement,the maximum plastic displacements of equivalent SDOF under rare earthquake are calculated,and it is compared with the maximum plastic displacements of member structures using nonlinear dynamic analysis.Finally,the advice of simplifying capacity spectrum is advanced.     

Limitation and improvement of the equivalent capacity method for calculating the energy loss of distribution networks

Through the analysis of the equivalent resistance method, a limitation of the equivalent capacity method was presented. When the direction of power at the feeder source end was changing, the equivalent capacity method for handling small generations would produce a large power loss calculation error. An improved calculation method, one not based on a single equivalent resistance, was proposed. In this method, one day was divided into several periods (such as 24 h), so that the direction of power at the feeder source end for each period does not vary. The equivalent resistance and energy loss in each period were calculated. The sum of all energy losses provided the daily energy loss total. Numerical examples were used to verify the improved method.     

峨嵋双蝴蝶提取物抑菌作用的研究

为解决峨眉双蝴蝶抑菌作用原理问题,运用滤纸片扩散法研究峨嵋双蝴蝶提取物对致病菌的抑菌作用。结果表明：峨嵋双蝴蝶提取物对金黄色葡萄球菌的抑制作用较强。不同方法提取的提取物中水提取物的抑菌效果最好。峨嵋双蝴蝶提取物对金黄色葡萄球菌的最低抑菌浓度(MIC)为3.125%。与青霉素溶液标准曲线对照,测得峨嵋双蝴蝶提取物的抑菌效价相当于0.77 U/mL,即61.72 U/mg。     

An Analysis of Thick Plates underIn-plane and Transversal Loadings by the BEM

In accordance with the behaviours of thick plates under the in-plane and transversal loadings,and introducing the concept of equivalent load, the coupled equations for the problem have been deduced with the theory of BEM in this paper.Thus a new method is presented for solving the problems of interaction of superstructure and foundation and subsoil,as well as for the problems of the thick plates under the complicated loadings.     

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.     

‘滇重楼’地上茎叶可利用性分析

为了研究‘滇重楼’地上部分的有效利用,在武定、云龙和马关3个‘滇重楼’主产县,从8月到11月逐月采取地上茎叶估测产量,采用气相色谱法测定茎叶中重楼皂苷Ⅰ、Ⅱ、Ⅵ、Ⅶ、PA及H的含量,分析各种成份的变化规律。结果表明地上茎叶干物质产量约900.0 kg/hm2,其总皂苷含量与地下根茎相当,可以入药;地上茎叶总皂苷主要成分是重楼皂苷Ⅱ和重楼皂苷Ⅶ,不含重楼皂苷H和重楼皂苷PA,也与地下根茎皂苷组成相近,可取得同样的药效;地上茎叶入药,新增产值2.7万元/hm2;开花植株地上茎叶皂苷含量比未开花植株高;果皮重楼皂苷的含量较高。‘滇重楼’地上茎叶可入药,可显著提高种植效益,促进产业发展。     

The Optimization Design for the Parameters of Capacitor Welding

Through the analysis in this paper,the optimum relation of the discharging current peak interval t m ,the discharging loop equivalent inductance L and equivalent resistance R is obtained.This paper analyze the original discharging loop equivalent inductance L ,which provides an effective method for adjustment and selection of inductance L to realize the optimization energy saving design of the welding machine.     

绿豆/黑豆压青还田下减量施肥对宿根甘蔗产量和主要农艺性状的影响

为探讨绿豆/黑豆还田和减施化肥条件下,间作绿肥压青还田对宿根甘蔗生长的影响及绿肥还田和有机肥施用对化肥的替代作用。试验设计了常规施肥（CK）、化肥减施25%+12%营养元素当量绿豆绿肥还田+13%营养元素当量有机肥（H-LY）、化肥减施25%+全量绿豆还田（H-LQ）、化肥减施25%+25%营养元素当量有机肥（H-Y）、化肥减施25%+25%营养元素当量黑豆绿肥还田（H-HD）和化肥减施25%+全量黑豆还田（H-HQ）6个处理。结果表明,与CK处理相比,宿根蔗间作绿豆和黑豆压青还田对甘蔗株高、有效茎数和单茎重没有显著影响,所有处理的蔗茎产量与CK处理无显著差异,说明宿根蔗间作绿豆和黑豆绿肥压青还田、当量有机肥施用均可以替代25%的甘蔗化肥。     

Equivalent Constitutive Equatlons with Polariiy and the Mechanism of Storing Energy of Honevcomb Materials in Plane Deformation

Equivalent couple-stresses and asymmetric equivalent stresees are introduced todescribe the equivalent constitutive equations of honeycomb materials in plane deformation,It is in-dicated from the field analysis of plane deformation accordin8 to the obtained constitutive equations-that this type of materials is of excellent capacity of storing energy.     

等值线和等值面生成算法在精准农业变量施肥中的应用

100083 北京市海淀区学院路丁11号中国矿业大学资源与安全工程学院硕03-1班     

考虑三维地震动作用下振动台试验隔震层简化

基于等效原则、相似理论,考虑三维地震动作用下振动台试验中原型结构隔震层的简化,并对模型结构隔震层进行系统研究。针对不同高宽比隔震结构,提出完全等效简化方法和部分等效简化方法,包括隔震垫等效、模型支座参数及坐标确定、相似关系确定等。利用不同高宽比隔震结构振动台试验,结合有限元数值模拟,进行方法验证。理论推导与数值模拟证明简化方法具有良好的准确性,且在误差允许范围内,简化后的隔震层所获得的加速度、速度、位移等动力特性与简化前相同,可以用于振动台试验模型设计。     

中国畜禽粪便资源结构分布及发展展望

随着近年来经济的发展和产业结构的调整,畜禽养殖业发展迅速,同时畜禽粪便的产生量也在迅速增加。为此利用全国第一次污染源普查的相关指标和相关文献中排泄系数,在综合考虑畜禽饲养周期的情况下,估算出2009年中国畜禽粪尿产生总量约为21.83亿t猪粪当量,其中河南、山东、四川和内蒙古的畜禽粪尿产生量均超过1.50亿t猪粪当量。并利用2020年畜禽产品需求量的预测值,估算出2020年的畜禽粪尿产生量为28.11亿t猪粪当量。通过对畜禽粪尿产生量的估算,有利于明确对畜禽粪便总量和分布的认识,为畜禽粪便处理方法的选取和相关政策的制定奠定基础。     

建国初期苏联援建国营友谊农场的积极意义

20世纪50年代,由苏联提供全部农机设备,派来不同层次专家援建的国营友谊农场,是新中国第一个按照先勘探、后设计、再开荒的科学程序建立的大型机械化国营农场,开荒当年获得丰收。它的建立,引入了土地整理和国营农场建设、管理的技术与经验;为中国大规模建设国营农场培养、锻炼和输出大批经营管理干部和技术人才,提供大量农业技术和良种;并在建场规划、开荒生产和经营管理等方面对全国国营农场建设起到示范和借鉴作用,达到了周恩来总理提出的“出粮食、出经验、出人才”的要求。     

砾石覆盖层截留降雨的模拟实验研究

砾石覆盖技术可减少土壤水分蒸发,在世界的一些干旱半干旱地区得到了不同程度的应用。但在降雨时,雨水通过覆盖层进入土壤的过程中,覆盖层也会截留一定的降雨量。此文通过模拟降雨实验,表明：在降雨强度、降雨历时和铺设方式等相同的条件下,烘干砾石的吸水量随着降雨历时的延长而增大,并逐渐达到饱和吸水量;烘干砾石达到吸水饱和所需的降雨历时随着砾石平均等效粒径的减小而缩短;随着砾石平均等效粒径的增加,覆盖层砾石颗粒间的滞留水量逐渐减少;饱和砾石覆盖层的截留水量也逐渐减小,用指数衰减拟合模型进行拟合,具有高度的显著性。     

Differential Competitive Ability and Growth Habit of Pearl Millet and Clusterbean Cultivars in a Mixed Cropping System in the Arid Zone of India

Dryland sustainable agriculture in the arid zone of India depends upon the choice of suitable cultivars for pure and mixed crop stands. Field experiments were conducted for two years to examine the response of two contrasting cultivars each of pearl millet (Pennisetum glaucum) and clusterbean (Cyamopsis tetragonoloba) in pure stands and in mixed pearl millet‐clusterbean stands. The differential response of cultivars of both crops to pure and mixed stands resulted in a significant genotype × cropping system interaction. Reduction in seed yield of both clusterbean cultivars was greater in mixed stands with tall and long duration pearl millet MH 179 than with medium statured and early maturing HHB 67. The degree of reduction was greater in Naveen, the branched clusterbean cultivar, than in RGC 197, the single stemmed cultivar. Mixing of pearl millet HHB 67 with medium duration clusterbean cultivar Naveen produced maximum pearl millet equivalent total yield. Higher land equivalent ratios (LERs) were also observed when clusterbean cultivars were mixed with early maturing and short statured pearl millet HHB 67.     

Fast modeling of the motor broadband equivalent circuit model

This paper proposes a modeling method of the motor broadband equivalent circuit model. The impedance amplitude-frequency characteristics of the motor terminal through measuring are obtained. The impedance amplitude-frequency characteristics are devided into several regions based on its first resonant point information,and the motor broadband circuit topology is developed with each region equaling a resonance unit. The RLC parameters of resonance unit are extracted through frequency and corresponding impedance of the any non-resonant and resonant point in each unit. This proposed method is used to build DC and AC motor broadband equivalent circuit model. Their impedance amplitude-frequency characteristics are simulated by the Saber software. The measurement results and the simulation result of references are compared. The DC motor simulation results coincide with the measurement results in 0.1~50 MHz,and the AC motor is in 0.1~40 MHz. The results show that the motor broadband circuit model is reliable and feasible.     

Influence of Transverse Flexural Crack on Chloride Penetration in Concrete

The mechanism for chloride penetration in cracked concrete and its major impact factors were analyzed. As a result, a revised chloride diffusion model based on Fick's Law was built by dual porous medium model. Then several cracked reinforced concrete beams self-anchored with sustained flexural loads were immersed in the 5% NaCl solution with the condition of dry-wet cycles. After 15 times of dry-wet cycles, the rapid chloride testing (RCT) was used for the determination of chloride ion content of the powder at each cracked sections. The test results show that: 1) with the condition of dry-wet cycles, the chloride content will occur a peak in the surface 20mm concrete, so the depth for surface convection zone can be assumed to be 15~20 mm; 2) when the crack width is less than 0.3mm, the equivalent chloride diffusion coefficient increases steadily, which agrees well with model's prediction; when the crack width is larger than 0.3mm, the equivalent chloride diffusion coefficient augments rapidly and influence of convection on chloride penetration becomes more significant; 3) the deterioration factor for equivalent chloride diffusion coefficient in flexural cracked concrete is directly correlative with crack width, which can be expressed by second order power function or separate function.     

混凝土拉压强度尺寸效应的细观非均质机理

为了从材料细观非均质角度揭示混凝土强度尺寸效应机理,建立了混凝土细观单元等效非均质力学模型,开展了立方体抗拉、抗压强度尺寸效应细观数值模拟研究。研究结果表明：混凝土强度尺寸效应根源于材料细观非均质性,随着模型尺寸的增加,混凝土材料细观单元弹性模量变异系数增大,材料细观非均质性增强,大尺寸模型内部存在更多的低强度单元或缺陷,导致混凝土立方体抗拉、抗压强度降低,极限应变减小,脆性增大;混凝土损伤破坏由少量集中区域,发散扩展形成多条非贯通的裂纹带;数值模拟结果与尺寸效应实验数据相吻合。     

Distributed Power Flow Method Based on Ward Equivalent

With interconnecting and developing of power system, the problem of power flow computation on dispersed data resource need to be solved. A new distributed computation method of power flow based on Ward equivalent is presented. According to master-slaver splitting principle, multi-area interconnected power system is divided into master-slaver areas. Boundary buses in different areas are defined as different bus-types. Neighborhood areas are equivalent by Ward equivalent principle, and the equivalent injection power and equivalent impedance are worked out. Power flows from master area to slaver areas are solved by Newton method, and the equivalent injection power and equivalent impedance on the boundary are modified by their solutions. The process above repeats until to convergence. The proposed distributed power flow method takes full advantage of the information of power, voltage, network configuration in neighborhood areas, so it is better on convergence and quality of solution. The proposed algorithm is testified by IEEE 14-bus system and a practical 181-bus system.     

Variation of the genomic proportion of the recurrent parent in BC1 and its relation to yield performance in sorghum (Sorghum bicolor) breeding for low-input conditions

In order to define the variation of the genomic proportion of the recurrent parent [G(RP)] and its relation to yield, G(RP) of individual BC₁ plants of two sorghum populations composed of a high‐yielding cultivar as recurrent parent (RP) and a donor with superior drought resistance or grain quality, respectively, was estimated using AFLPs and SSRs. G(RP) in BC₁ ranged from 0.53 to 0.95 and averaged to 0.76 in the population (NP4453 × ‘SV‐2’) × ‘SV‐2’. G(RP) varied between 0.60 and 0.86 and averaged to 0.74 in the BC₁ of (ICV‐219 × ‘SV‐2’) × ‘SV‐2’. Results show that plants with a G(RP) equivalent to BC₂ (0.875) or BC₃ (0.938), respectively, can be selected from BC₁. Yield performance of BC₁S₁ families was tested in field trials carried out in South Africa. The correlation between yield and G(RP) in BC₁ was low. Selection according to G(RP) did not result in an effective preselection for yield.