基于随机森林算法的WANO机组能力因子分类

针对核电厂机组能力因子分类研究缺少相对简单有效的方法,基于第一至第八次《中华人民共和国核安全公约国家报告》中世界核电营运者协会(WANO)性能指标的数据,提出一种随机森林模型(random forest,RF)的机组能力因子分类方法,通过估算随机森林模型决策树的棵树、内部节点再划分所需要的最小样本数等,构建最优的随机森林分类模型,成功实现对能力因子的快速和精细分类,为第九次国家报告中定性掌握我国核电机组发电状况及行业内机组所处状况提供依据;同时,选用解决二分类的Logistic回归作对比试验,试验结果表明RF分类算法的总体精度达到77.27%,Kappa系数为0.7053,达到高度一致性检验标准区间,明显高于Logistic回归的51.14%和0.1101,RF表现出分类效果好、准确率高和性能稳定等优点,能够有效提高机组能力因子分类的准确度。

市场环境下发电机组竞争能力的关联规则挖掘方法

针对常规的模糊综合评判中各因素的模糊化区间以及各因素之间的关联性对选择权重的影响,提出了应用关联规则的数据挖掘算法修正权重的新方法。首先对电力市场中发电商的竞争数据库进行挖掘并寻找发电商竞争能力评估体系中各因素之间的关联关系;然后根据关联关系的强弱分析了各因素权重设置的合理性并重新修正了权重因子;最后建立了合理的模糊综合评判模型并将其应用于电力市场中发电商竞争能力的评判决策。数字仿真结果表明了该方法的有效性。

发电机组进相能力挖掘技术研究

近年来电网低负荷运行时,电压偏高问题越来越突出,迫切需要机组具备更强的进相能力。大部分机组进相试验获得的进相能力相对于低负荷期间机组实际进相能力偏保守,具有进相能力挖掘的潜力。文章提出改变试验条件提升试验确定的机组进相能力、通过仿真提升进相能力方法和基于实测数据的进相能力挖掘方法,并分析这几种进相能力挖掘技术的优缺点,为挖掘机组进相潜力、在电网低负荷期间发挥更大的进相潜力提供可行思路。

深化配煤掺烧中提升机组盈利能力探究

文章将详细介绍配煤掺烧的技术手段,并提出加强配煤掺烧质量监督、规范燃料管理水平、建设配煤掺烧动态管理系统、改进输煤控制系统及改善配煤掺烧配置方式五项提高机组盈利能力的具体措施,通过挖掘配煤设施的潜力,修改配煤掺烧的管理方式与技术手段,从而提高机组盈利能力。

贵冶ISA法极板处理机组

贵冶是国内第一家采用ISA法铜电解工艺的工厂,本文对与ISA法工艺配套的极板机组的功能以及自投产以来机组的加工能力、加工质量等情况进行了介绍,同时对机组在实际生产过程中出现的问题进行了总结。

商用陈列柜选用机组探讨

随着便利店、超市和购物中心等的不断发展，商用陈列柜也得到了广泛的应用。由于陈列柜的低能耗对于保护环境、节约电力和降低运行费用等都有十分重要作用，因此陈列柜的设计制造者和使用者都十分重视它。本文分析了影响陈列柜冷冻负荷和冷冻能力的因素，阐明了温度对冷冻负荷和冷冻能力的影响，对比了多台并联压缩机组和单台压缩机组的特点，为实际机组的选配和使用奠定了基础。

Effect of thermo-mechanical treatment on microstructure and mechanical properties of wire-arc additively manufactured Al-Cu alloy

Wire-arc additive manufacture(WAAM)has great potential for manufacturing of Al-Cu components.However,inferior mechanical properties of WAAM deposited material restrict its industrial application.Inter-layer cold rolling and thermo-mechanical heat treatment(T8)with pre-stretching deformation between solution and aging treatment were adopted in this study.Their effects on hardness,mechanical properties and microstructure were analyzed and compared to the conventional heat treatment(T6).The results show that cold rolling increases the hardness and strengths,which further increase with T8 treatment.The ultimate tensile strength(UTS)of 513 MPa and yield stress(YS)of 413 MPa can be obtained in the inter-layer cold-rolled sample with T8 treatment,which is much higher than that in the as-deposited samples.The cold-rolled samples show higher elongation than that of as-deposited ones due to significant elimination of porosity in cold rolling;while both the T6 and T8 treatments decrease the elongation.The cold rolling and pre-stretching deformation both contribute to the formation of dense and dispersive precipitatedθ′phases,which inhibits the dislocation movement and enhances the strengths;as a result,T8 treatment shows better strengthening effect than the T6 treatment.The strengthening mechanism was analyzed and it was mainly related to work hardening and precipitation strengthening.

西安北站真空卸污设施设计及应用探讨

西安北站是目前亚洲车场规模最大的特大型高速铁路客运站,站场布置为一站三场,共18个站台34条股道,是站场真空卸污设施设计比较复杂的车站之一。郑西场真空卸污设施在实际运行过程中,因为列车停留时间缩短,出现卸污能力不足等问题,从列车卸污停时整备要求出发,分析影响真空卸污能力的各种因素,并对真空机组配置及真空管道进行优化设计,以满足复杂且多站场车站的卸污需要。

Effects of ultrasonic treatment on microstructure and mechanical properties of Mg-5Zn-2Er alloy

The effects of ultrasonic treatment on the microstructure and mechanical properties of Mg-5Zn-2Er alloy at room temperature （RT） and high temperature （HT） were investigated. The microstructure and mechanical properties of the samples were studied by OM, SEM and MTS material tester. The results show that the microstructure and mechanical properties are improved after the ultrasonic vibration. The best effects of ultrasonic vibration on microstructure and mechanical properties were obtained with the ultrasonic vibration power of 600 W and time of 100 s. The cavitation and acoustic streaming caused by ultrasonic treatment play a major role in refining the microstructure and increasing mechanical properties of the alloy.

Preparation, formation mechanism and mechanical properties of multilayered TiO_2-organic nanocomposite film

Ti O2-organic multilayered nanocomposite films were deposited on a self-assembled monolayer-coated silicon substrate based on layer-by-layer technique and chemical bath deposition method by a hydrolysis of Ti Cl4 in an acid aqueous solution. The chemical compositions, surface morphologies and mechanical properties of the films were investigated by X-ray photoelectron spectrometer(XPS), scanning electron microscopy(SEM) and nanoindentation depth-sensing technique, respectively. The results indicate that the major chemical compositions of the films are Ti and O. The principal mechanism for the nucleation and growth of the films is homogeneous nucleation, and the layer number of films has great influence on the surface morphology and roughness of the films. In addition, mechanical nanoindentation testing presents a significant increase in hardness and fracture toughness of titanium dioxide multilayered films compared with single-layer titanium dioxide thin film.

Effects of minor Sc and Zr additions on mechanical properties and microstructure evolution of Al−Zn−Mg−Cu alloys

The effects of minor Sc and Zr additions on the mechanical properties and microstructure evolution of Al Zn Mg Cu alloys were studied using tensile tests, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The ultimate tensile strength of the peak-aged Al Zn Mg Cu alloy is improved by about 105 MPa with the addition of 0.10% Zr. An increase of about 133 MPa is observed with the joint addition of 0.07% Sc and 0.07% Zr. For the alloys modified with the minor addition of Sc and Zr (0.14%), the main strengthening mechanisms of minor addition of Sc and Zr are fine-grain strengthening, sub-structure strengthening and the Orowan strengthening mechanism produced by the Al3(Sc,Zr) and Al3Zr dispersoids. The volume of Al3Zr particles is less than that of Al3(Sc,Zr) particles, but the distribution of Al3(Sc,Zr) particles is more dispersed throughout the matrix leading to pinning the dislocations motion and restraining the recrystallization more effectively.

Interfacial microstructure and mechanical behavior of Mg/Cu bimetal composites fabricated by compound casting process

Mg/Cu bimetal composites were prepared by compound casting method, and the microstructure evolution, phase constitution and bonding strength at the interface were investigated.It is found that a good metallurgical bonding can be achieved at the interface of Mg and Cu,which consists of two sub-layers,i.e.,layer I with 30μm on the copper side composed of Mg2Cu matrix phase, on which a small amount of dendritic MgCu2 phase was randomly distributed;layerⅡ with 140μm on the magnesium side made up of the lamellar nano-eutectic network Mg2Cu+(Mg) and a small amount of detached Mg2Cu phase. The average interfacial shear strength of the bimetal composite is measured to be 13 MPa.This study provides a new fabrication process for the application of Mg/Cu bimetal composites as the hydrogen storage materials.

2010 Industrial Report on Small and Medium Size Wind Turbines in China

The development of small and medium wind turbine industry in 2010 is presented, including the production capability, the mainstream products and the main producers. Suggestions for future's development are also put forward.

提高传统法电解作业率

介绍了传统法电解工序,大量外购阳极后,增加了作业流程,作业时间延长,影响了作业率。通过创新短路处理的方式,释放一台行车参加作业;解决机组吞吐能力不足,提升阳极、始极片存储能力;优化作业方式,将单系统作业,提升为双系统同时作业。不仅提高了作业率,也节约了成本。

Force modeling for needle insertion into soft tissue based on mechanical properties and geometric parameters

The force model during needle insertion into soft tissue is important for accurate percutaneous intervention.In this paper,a force model for needle insertion into a tissue- equivalent material is presented and a series of experiments are conducted to acquire data from needle soft- tissue interaction process.In order to build a more accurate insertion force model,the interaction force between a surgical needle and soft tissue is divided into three parts:stiffness force,friction force,and cutting force.The stiffness force is modeled on the basis of contact mechanics model.The friction force model is presented using a modified Winkler' s foundation model.The cutting force is viewed as a constant depending on a given tissue.The proposed models in the paper are established on the basis of the mechanical properties and geometric parameters of the needle and soft tissue.The experimental results illustrate that the force models are capable of predicting the needle-tissue interaction force.The force models of needle insertion can provide real-time haptic feedback for robot-assisted procedures,thereby improving the accuracy and safety of surgery.

A novel method to improve interfacial bonding of compound squeeze cast Al/Al-Cu macrocomposite bimetals:Simulation and experimental studies

A facile and innovative method to improve bonding between the two parts of compound squeeze cast Al/Al-4.5 wt.%Cu macrocomposite bimetals was developed and its effects on microstructure and mechanical properties of the bimetal were investigated.A special concentric groove pattern was machined on the top surface of the insert(squeeze cast Al-4.5 wt.%Cu) and its effects on heat transfer,solidification and distribution of generated stresses along the interface region of the bimetal components were simulated using ProCAST and ANSYS softwares and experimentally verified. Simulation results indicated complete melting of the tips of the surface grooves and local generation of large stress gradient fields along the interface. These are believed to result in rupture of the insert interfacial aluminum oxide layer facilitating diffusion bonding of the bimetal components. Microstructural evaluations confirmed formation of an evident transition zone along the interface region of the bimetal. Average thickness of the transition zone and tensile strength of the bimetal were significantly increased to about 375 μm and 54 MPa, respectively, by applying the surface pattern.The proposed method is an affordable and promising approach for compound squeeze casting of Al-Al macrocomposite bimetals without resort to any prior cost and time intensive chemical or coating treatments of the solid insert.

Localized Manufacture of Nuclear Power Equipment in China

The paper expresses the view that China's essential way out for developing nuclear power lies in localization of manu facture, based on her technical level and capability in designing and manufacturing nuclear power equipment. Moreover, the paper opines that domestically manufactured nuclear power equipment has a certain competitive potential with respect to quality and price, the crux lying in the neces sity of reforming the management system of nuclear power.

Effect of Temperature Differentials on Condensers of Split-Type Air Conditioners in Apartment Buildings

Analyzing the effects of heat rejection from condensers of split-type air-conditioning units at lower-floors of MLABs （multi-level apartment buildings）, using field measurements to monitor environmental conditions and condenser operation, revealed increases in the inlet air temperature at the condensers at the upper floors, which in turn increased the power and energy requirements for these units and decreased their cooling capacities. Results indicated that a decrease of up to 16,000 tons in cooling capacity and an increase of up to 67.2 MW in the national peak load demand might be reached for a 4 ℃ temperature differential for Kuwait conditions. It is recommended that the condensers be placed in the wind pathway to minimize the impact of heat rejection and stack effect and to optimize the operation of split-type air-conditioning units, and that other factors regarding installation setup and location are investigated.