镀锌钢三价铬彩色钝化工艺优选

为了开发环保型的镀锌层彩色钝化液,以正交试验和极差分析的方法,研究了镀锌层表面三价铬彩色钝化液的组成,通过单因素试验法研究了成膜温度、p H值、钝化时间、空停时间及干燥方式对钝化膜外观颜色及耐蚀性能的影响,并对工艺参数进行优化。结果表明:钝化液的最佳组分为7.5 g/L硝酸铬、6.0 g/L柠檬酸、1.0 g/L硝酸钠、1.0 g/L硫酸钴、2.0 g/L氯化钠;最佳工艺参数为p H值2.5,成膜温度35℃,钝化时间90 s,空停时间20s,电吹风干燥;采用本法对镀锌层进行彩色钝化,膜表面质量及耐腐蚀性能最好。

普通骨料优选化在超高层泵送混凝土中的应用研究

本文通过基础实验、正交优化试验以及对比分析,以骨料空隙率、混凝土工作性能与力学性能为指标,研究了普通骨料优选化在泵送混凝土中的应用,结果表明:普通碎石优选化最佳级配设计为G3组,普通砂优选化最佳级配设计为S2与S4;普通骨料优化的最佳级配比例为碎石级配设计G3,砂级配设计S4,砂率47%,各因素显著性优劣顺序:砂级配设计>碎石级配设计>砂率;在实际生产中,普通骨料优选化级配范围在各号筛最佳累计筛余基础上可上下浮动至2%;依托西安国瑞金融中心超高层施工项目,采用优选化普通骨料制备的C60混凝土成功泵送至350m,在大幅降低生产成本的情况下实现了普通骨料在超高层泵送混凝土中的有效应用。

浅论教学文化

在课程改革中,教学文化的作用日益凸显。教学文化具有内隐性、特殊性和优选纯粹性。要建设优质的教学文化,需要处理好师生关系、生生关系和学生与知识的关系。

气象预报模式参数化方案对重污染过程PM2.5浓度预报效果的影响

针对北京市2016年12月16~21日的重污染过程,基于嵌套网格空气质量模式预报系统(NAQPMS),面向气象驱动模式WRF中7类物理过程的参数化方案,通过单扰动和组合扰动方式构建了51组不同的WRF模式运行配置,对比分析不同方案配置下NAQPMS对这次重污染过程细颗粒物(PM2.5)浓度预报的性能。结果表明:在重污染时段,组合扰动优化方案在城中心站点和城郊站点的PM2.5浓度预报精度都显著高于基准参数化方案配置下的预报结果,特别是能显著改进基准方案下模式对重污染过程结束时间的预报误差问题,显著减小12月21日存在的预报偏差。从统计指标来看,城中心站点在组合扰动优化方案下预报相关性最高,相关系数在0.7以上;从预报均方根误差来看,组合扰动优化方案误差最小。城郊站点同样是在组合扰动优化方案下预报相关性最高,与观测之间的偏差更小。从污染物与气象要素的空间分布来看,组合扰动优化方案比基准方案能更好再现污染时段的气象要素变化,预报的风速更小、相对湿度更高,从而有利于12月21日北京高浓度PM2.5的维持和累积。本文结果表明气象预报模式参数化方案不确定性是重污染预报的关键不确定性来源,选择合适的参数化方案可以减小重污染期间气象要素的模拟偏差,并可进一步提高重污染时段的PM2.5浓度预报精度。

卡封酸化管柱优化与设计在文南油田的应用

随着油田精细开发工作的不断深入,注水面临主要困难是油层深、注水压力高,如何有效实施卡封井的酸化作业以达到增注的目的成为一个亟需解决的问题。采油四厂在积极引进新技术新工艺的基础上,集思广益、锐意创新,在卡封酸化管柱和方案设计的优选优化上找思路、寻突破,取得了明显的效果。

PP与OT的理论构建对比

优选论是新近发展起来的生成语言学的一个分，它为语言分析提供的新视角对生成语言学中一些传统的理论提出了严重挑战，本文拟从理论目标，研究思路，理论框架和分析方法等方面对生成语言学中传统的原则参数模型和优选论进行比较， 从中可以看出优选论对传统的生成语言学思想有哪些继承和突破。

Topology optimization of microstructure and selective laser meltingfabrication for metallic biomaterial scaffolds

The precise design and fabrication of biomaterial scaffolds is necessary to provide a systematic study for bone tissue engineering. Biomaterial scaffolds should have sufficient stiffness and large porosity. These two goals generally contradict since larger porosity results in lower mechanical properties. To seek the microstructure of maximum stiffness with the constraint of volume fraction by topology optimization method, algorithms and programs were built to obtain 2D and 3D optimized microstructure and then they were transferred to CAD models of STL format. Ti scaffolds with 30% volume fraction were fabricated using a selective laser melting （SLM） technology. The architecture and pore shape in the metallic biomaterial scaffolds were relatively precise reproduced and the minimum mean pore size was 231μm. The accurate fabrication of intricate microstructure has verified that the SLM process is suitable for fabrication of metallic biomaterial scaffolds.

Gravity and magnetic anomalies field characteristics in the South China Sea and its application for interpretation of igneous rocks

Igneous rocks in the South China Sea have broad prospects for oil and gas exploration.Integrated geophysical methods are important approaches to study the distribution of igneous rocks and to determine and identify igneous rock bodies.Aimed at the characteristics of gravity and magnetic fields in the South China Sea,several potential field processing methods are preferentially selected.Reduction to the pole by variable inclinations in the area of low magnetic latitudes is used to perform reduction processing on magnetic anomalies.The preferential continuation method is used to separate gravity and magnetic anomalies and extract the gravity and magnetic anomaly information of igneous rocks in the shallow part of the South China Sea.The 3D spatial equivalent distribution of igneous rocks in South China Sea is illustrated by the 3 D correlation imaging of magnetic anomalies.Since the local anomaly boundaries are highlighted gravity and magnetic gradients,the distribution characters of different igneous rocks are roughly outlined by gravity and magnetic correlation analysis weighted by gradient.The results show the distribution of igneous rocks is controlled and influenced by deep crustal structure and faulting.

Molecular Dynamic Simulation on the Absorbing Process of Isolating and Coating of α-olefin Drag Reducing Polymer

The absorbing process in isolating and coating process of α-olefin drag reducing polymer was studied by molecular dynamic simulation method, on basis of coating theory of α-olefin drag reducing polymer particles with polyurethane as coating material. The distributions of sodium laurate, sodium dodeeyl sulfate, and sodium dodeeyl benzene sulfonate on the surface of α-olefin drag reducing polymer particles were almost the same, but the bending degrees of them were obviously different. The bending degree of SLA molecules was greater than those of the other two surfactant molecules. Simulation results of absorbing and accumulating structure showed that, though hydrophobie properties of surfactant molecules were almost the same, water density around long chain sulfonate sodium was bigger than that around alkyl sulfate sodium. This property goes against useful absorbing and accumulating on the surface of α-olefin drag reducing polymer particles; simulation results of interactions of different surfactant and multiple hydroxyl compounds on surface of particles showed that, interactions of different surfaetant and one kind of multiple hydroxyl compound were similar to those of one kind of surfaetant and different multiple hydroxyl compounds. These two contrast types of interactions also exhibited the differences of absorbing distribution and closing degrees to surface of particles. The sequence of closing degrees was derived from simulation; control step of addition polymerization interaction in coating process was absorbing mass transfer process, so the more closed to surface of particle the multiple hydroxyl compounds were, the easier interactions With isoeyanate were. Simulation results represented the compatibility relationship between surfactant and multiple hydroxyl compounds. The isolating and coating processes of α-olefin drag reducing polymer were further understood on molecule and atom level through above simulation research, and based on the simulation, a referenced theoretical basis was provided for practical optimal selection and experimental preparation of α-olefin drag reducing polymer particles suspension isolation agent.

Antioxidase Activities of Tetraploid Lines and Diploid Control Line of Chrysanthemum cinerariifolium

Objective The SOD, POD and APX enzyme activities of tetraploid lines and diploid control line of Chrysanthemum cinerariifolium in test-tube and field were determined in order to provide a reference for the selective breeding of high resistance good tetraploid varieties of C. cinerariifolium. Method The SOD, POD and APX activities of each sample were determined. Every material should have 3 replicates which been determined and calculated mean value to analyze. Result The various kinds of antioxidase activities in protective enzyme system of tetraploid lines were increased generally in comparison with that of diploid control line. And there is certain relativity between the samples in field and in test-tube of these lines. Conclusion The antioxidase activities of each line in test-tube could be considered as reference index to screen high resistance good tetraploid varieties of C. cinerariifolium.

Machine tool selection based on fuzzy evaluation and optimization of cutting parameters

The paper analyzes the factors influencing machine tool selection. By using fuzzy mathematics theory, we establish a theorietical model for optimal machine tool selection considering geometric features, clamping size, machining range, machining precision and surface roughness. By means of fuzzy comprehensive evaluation method, the membership degree of machine tool selection and the largest comprehensive evaluation index are determined. Then the reasonably automatic selection of machine tool is realized in the generative computer aided process planning （CAPP） system. Finally, the finite element model based on ABAQUS is established and the cutting process of machine tool is simulated. According to the theoretical and empirical cutting parameters and the curve of surface residual stress, the optimal cutting parameters can be determined.

Location problem of emergency supplies reserve storages under disease diffusion environment

Under the threat of bio-terrorism,this paper aims at improving the emergency rescue system's ability of dealing with a public health emergency.Focusing on the demand network,this research establishes the emergency rescue supply storage network under a danger diffusion environment.Combined with the infectious disease diffusion model,the traditional set covering model is rebuilt taking the decision optimization of reserve quantity into consideration.Under the premise of a certain emergency service level,the collaborative location optimizing model of an emergency rescue supply storage network is established in order to minimize the sum of the building costs and the preserving costs.The model is proved to be effective through numerical simulation.The collaborative location optimization of the nodes of the emergency rescue supply storage network and the reserve quantity of each storage node is realized.

基于TOPSIS的长江上游流域降水模拟与预报研究

为研究长江上游流域高精度的短期降水模拟和预报,优选适宜于流域的WRF模式参数化方案组合,构建了模式中不同微物理过程、陆面过程和积云参数化方案组合,建立了包含平均绝对误差、布莱尔评分、TS评分和合格率多个指标的定量综合评价体系,提出了基于TOPSIS多属性决策的最优参数化方案优选方法,并在长江上游流域选取了4场典型强降雨过程进行模拟分析。研究结果表明:在长江上游流域采用微物理过程WSM3方案、陆面过程Noah方案、积云参数KF方案条件下,WRF模拟降水与实测降水的空间分布和降水量级更为相符。

Method for test case selection and execution of web application regression testing

In order to improve the efficiency of regression testing in web application,the control flow graph and the greedy algorithm are adopted.This paper considers a web page as a basic unit and introduces a test case selection method for web application regression testing based on the control flow graph.This method is safe enough to the test case selection.On the base of features of request sequence in web application,the minimization technique and the priority of test cases are taken into consideration in the process of execution of test cases in regression testing for web application.The improved greedy algorithm is also raised resulting in optimization of execution of test cases.The experiments indicate that the number of test cases which need to be retested is reduced,and the efficiency of execution of test cases is also improved.

Enhancing recovery of uranium column bioleaching by process optimization and kinetic modeling

This research aimed to enhance the column bioleaching recovery of uranium ore by Acidithiobacillus ferrooxidans.Seven factors were examined for their significance on bioleaching using a Plackett-Burman factorial design.Four significant variables([Fe2+]initial,pH,aeration rate and inoculation percent)were selected for the optimization studies.The effect of these variables on uranium bioleaching was studied using a central composite design(CCD).The optimal values of the variables for the maximum uranium bioleaching recovery(90.27±0.98)%were as follows:[Fe2+]initial=2.89g/L,aeration rate420mL/min,pH1.45and inoculation6%(v/v).[Fe2+]initial was found to be the most effective parameter.The maximum uranium recovery from the predicted models was92.01%.This value was in agreement with the actual experimental value.The analysis of bioleaching residue of uranium ore under optimum conditions confirmed the formation of K-jarosite on the surface of minerals.By using optimal conditions,uranium bioleaching recovery is increased at column and jarosite precipitation is minimized.The kinetic model showed that uranium recovery has a direct relation with ferric ion concentration.

The coalbed methane production potential method for optimization of wells location selection

A gas production potential method for optimization of gas wellsite locations selection is proposed in terms of the coalbed gas resources volume and the recoverability. The method uses the actual data about reservoirs in a coalbed gas field in central China to optimize wellsite locations in the studied area in combination with the dynamic data about actual production in the coalbed gas field, selects a favorable subarea for gas wells deployment. The method is established based on the basic properties of coal reservoirs, in combination with the coalbed thickness and the gas content to make an analysis of the gas storage potential of a coal reservoir, as well as resources volume and the permeability of a coal reservoir. This method can be popularized for optimization of wellsite locations in other methane gas development areas or blocks.

RECEIVE ANTENNA SUBSET SELECTION BASED ON ORTHOGONAL COMPONENTS

A new receive antenna subset selection algorithm with low complexity for wireless Multipie-Input Multiple-Output （MIMO） systems is proposed, which is based on the orthogonal components of the channel matrix. Larger capacity is achieved compared with the existing antenna selection methods. Simulation results of quasi-static fiat fading channel demonstrate the significant performance of the proposed selection algorithm.

Reducing energy consumption optimization selection of path transmission routing algorithm in opportunistic networks

Opportunistic networks are random networks and do not communicate with each other among respective communication areas.This situation leads to great difficulty in message transfer.This paper proposes a reducing energy consumption optimal selection of path transmission(OSPT) routing algorithm in opportunistic networks.This algorithm designs a dynamic random network topology,creates a dynamic link,and realizes an optimized selected path.This algorithm solves a problem that nodes are unable to deliver messages for a long time in opportunistic networks.According to the simulation experiment,OSPT improves deliver ratio,and reduces energy consumption,cache time and transmission delay compared with the Epidemic Algorithm and Spray and Wait Algorithm in opportunistic networks.

Optimization of selective leaching of Zn from electric arc furnace steelmaking dust using response surface methodology

The aim of this work is to investigate and optimize the effects of the leaching parameters on the selective leaching of zinc from electric arc furnace steelmaking dust （EAFD）. The response surface method was applied on the basis of a three-level Box–Behnken experimental design method for optimization of selective leaching parameters of zinc from EAFD. The leaching recoveries of zinc （YZn） and iron （YFe） were taken as the response variables, where the concentration of sulphuric acid （X1, mol/L）, leaching temperature （X2, °C）, leaching time （X3, min）, and liquid/solid ratio （X4, mL/g） were considered as the independent variables （factors）. The mathematical model was proposed. Statistical ANOVA analysis and confirmation tests were applied. A maximum of 79.09% of zinc was recovered while the minimum iron recovery was 4.08% under the optimum conditions of leaching time 56.42 min, H2SO4 concentration 2.35 mol/L, leaching temperature 25 °C and liquid/solid ratios. By using ANOVA, the most influential factors on leaching of zinc and iron were determined as H2SO4 concentration and leaching temperature, respectively. The proposed model equations using response surface methodology show good agreement with the experimental data, with correlation coefficients （R2） of 0.98 for zinc recovery and 0.97 for iron recovery.

Coordinated optimization setting of reagent dosages in roughing-scavenging process of antimony flotation

Considering the influence of reagent adjustment in different flotation bank on the final production index and the difficulty of establishing an effective mathematical model,a coordinated optimization method for dosage reagent based on key characteristics variation tendency and case-based reasoning is proposed.On the basis of the expert reagent regulation method in antimony flotation process,the reagent dosage pre-setting model of the roughing–scavenging bank is constructed based on case-based reasoning.Then,the sensitivity index is used to calculate the key features of reagent dosage.The reagent dosage compensation model is constructed based on the variation tendency of the key features in the roughing and scavenging process.At last,the prediction model is used to finish the classification and discriminant analysis.The simulation results and industrial experiment in antimony flotation process show that the proposed method reduces fluctuation of the tailings indicators and the cost of reagent dosage.It can lay a foundation for optimizing the whole process of flotation.