拱型金属可缩性支架附件配设浅析

在同一地质条件巷道内对于同一类型拱型可缩性金属支架通过改变支架附件配设数量,就可以大大提高支架的支承能力,从而提高支架的支护效果。

基于AHP的Reduce Task预设配比在Hadoop调度中的应用

针对Hadoop在进行具体MapReduce任务调度时,所存在的Reduce Task无法在一个合适的Map Task完成比例启动的问题,提出了一种基于AHP的R educe Task预设配比启动方案。该方案基于层次分析法(AHP),选取在资源调度时影响性能息息相关的三个参考指标:文件上传时间、Reduce完成度(Map完成100%)以及系统的响应时间,经过实验得到三个参考值,最后经归一化后进行多属性决策分析得到最佳的Reduce Task启动方案。在本文实验环境下的最佳R educe Task最佳启动配比为40%,即当Map Task完成比例为总数的40%时开始启动R educe Task任务。

滤料层填设模式对含聚污水过滤性能的影响

为优化含聚污水处理工艺,从压力式过滤器滤料层填设模式多元化设计思路出发,建立以滤料层和垫料层多种模式填设为主体的相应模型,数值模拟研究滤料层填设模式对含聚污水压力式过滤处理效果的影响。研究结果表明:随着污水中含聚质量浓度的增大,过滤流场趋向不稳定特征,且滤料的截污性能变差,在均质滤料过滤含聚污水中,除油率和悬浮物去除率从含聚浓度为150 mg/L时的68. 30%和56. 46%下降到含聚质量浓度为820 mg/L时的37. 14%和29. 06%;滤料层填设从均质模式改变为级配模式时,不同含聚污水的过滤流场均向着稳定特征方向演变,过滤层的截污能力提升,双层级配滤料模式适合于含聚污水的过滤处理;当污水中含聚质量浓度增大至820 mg/L时,双层级配滤料模式下的除油率和悬浮物去除率较均质滤料模式分别提高15. 58%和18. 08%。研究结果可为油田含聚污水个性化处理工艺的构建提供依据。

游船码头规划设计初探

对游船码头规划设计的选址、功能组成、平面布局、立面造型、竖向设计、风格塑造、配景设置等方面内容结合实例进行了较详尽的阐述,对游船码头规划设计的基本理论和设计要点做了归纳和总结。

含聚污水压力式深度过滤工艺模式构建及优化

以对含聚污水进行深度处理、满足回注为思路,数值模拟研究含聚污水经普通处理后进一步开展深度过滤处理的可行性及潜力。通过分析比较过滤流场的油珠及悬浮物粒子聚集分布、过滤出水水质含油与悬浮物质量浓度变化,以及除油率和悬浮物去除率的定量,构建并优化了适合于含聚污水压力式深度过滤的工艺模式。结果表明,“双层级配滤料+三层级配滤料”两级深度过滤工艺模式可依靠水力、界面效应实现进一步截污,再现出稳定的过滤性能,综合除油率和悬浮物去除率分别达到87.78%和87.11%,滤后水质的含油、悬浮物指标均可控制在深度处理水源要求的5mg/L以内,是含聚污水深度处理的一种潜在过滤工艺模式,为有效应对油田化学驱三次采油开发中的水质问题提供了依据。

提高铁路区域调车机车能力的探讨

保证机力充足是加快车流周转、提高运输效率的基础。在不增加机力投入的前提下,通过对区域调车机车的作业范围、管辖区段、调车作业量进行分析,进行合理配设、精细指挥、定期分析,达到加快车辆周转和提高运输效率的目标。

Development and Application of the Professional Software for Formulation Optimization Design

Aim To research the computer optimization design in material formulation. Methods The professional software including experimental design, mathematical modeling and optimization of single and multiple purposes was developed and applied to the formulation design for the flame retardant ethylenepropylene-diene mischpolymer (EPDM) insulation composites. With the aid of equipartition design, the mathematical models were established based on the optimization of the four properties (limiting oxygen index, volume resistance, tensile strength and elongation). Results The models from limited experiments had good significance, and the modeling analysis conclusions were in good agreement with later experiments. The optimization formulation was practically excellent. Conclusion The software enables practically a comprehensive multi-purpose use of material formulation research.

Integrated Assembly Structure Design Within Concurrent Engineering

Taking a microwave product as an example, a system of integrated assembly structure design is presented. Getting design constraints from the upstream design section through product data management(PDM), the system generates the assembly scheme using the case? based method, then assigns the design requirements into each component of the assembly. The detail design for each component can be performed under these design constraints. In order to practise concurrent design, the system sends the final design result to the upstream section and downstream section through PDM to achieve information sharing and integration.

Thermodynamic analysis on synthesis of fibrous Ni-Co alloys precursor and Ni/Co ratio control

According to the principles of simultaneous equilibrium and mass equilibrium, a series of thermodynamic equilibrium equations in Ni（II）-Co（II）-C2O4^2--NH3-NH4^＋-H2O system at ambient temperature were deduced. The diagrams of logarithm ion concentrations versus pH values at different solution compositions were drawn. The results show that Ni^2＋ and Co^2＋ can completely precipitate at pH less than 5.0 and the predefined Ni/Co ratios can be well kept in the precursor. The precursor morphology is granular aggregation. However, rod aggregation precursor is obtained in the pH range of 5.0-8.0, and fibre-shape precursor is got at pH value higher than 8.0. The Ni/Co ratios in the above two precursors are not reproduced as that in the feed due to the formhtion of multi-coordinated Ni（NH3）n^2＋ and Co（NH3）n^2＋ （n=1-6）. Modification of precipitation medium is favorable for the precursors to keep the predefined Ni/Co ratios of the feed in the pH range of 2.0-8.6. Meanwhile, the precursors with fibrous morphology can be obtained.

Optimum Design of Impedance Simulator for Phased Array Antnnas

The impedance of a solid state active phased array antenna varing with frequency and beam scanning scanning angle be matched with the solid state active matching network (SSAMN). In order to adjust and measure the radar conveniently and Securely, it is necessary for the impedance of the simulator of the phased array antennas to be optimized.Having selected the PIN dilde controlling circuits and the circuit parameters optimized,the simulator circuit is determined through numerical computation The experiment is given in support of the simulation.

PARAMETERIZED-PROTOTYPE-BASED DYNAMIC OPTIMIZATION DESIGN FOR CAM PROFILE

Aiming at the problems in current cam profile optimization processes, such as simple dynamics models, limited geometric accuracy and low design automatization level, a new dynamic optimization mode is put forward. Based on the parameterization modeling technique of MSC. ADAMS platform, the different steps in current mode are reorganized, thus obtaining an upgraded mode called the ＂parameterized-prototype-based cam profile dynamic optimization mode＂. A parameterized prototype（PP） of valve mechanism is constructed in the course of dynamic optimization for cam profiles. Practically, by utilizing PP and considering the flexibility of the parts in valve mechanism, geometric accuracy and design automatization are improved.

RESEARCH OF THE PARAMETRIC ASSEMBLY METHOD

The parametric part assembly generation method is presented. Based on the parametric part generated by means of constructive-element, through interactively inputting the relationships of the location and the assembly, and by compiling operations like movement and rotation, the assembly drawing is created so as to implement the occurrence of the parameterizations of the assembly and the part drawing. The data structure of the assembly part and the key technologies of hidden line removal in the implementation of assembly process, etc. , are described in detail.

Geological adaptability matching design of disc cutter using multicriteria decision making approaches

Geological adaptability matching design of a disc cutter is the prerequisite of cutter head design for tunnel boring machines(TBMs)and plays an important role in improving the tunneling efficiency of TBMs.The main purpose of the cutter matching design is to evaluate the cutter performance and select the appropriate cutter size.In this paper,a novel evaluation method based on multicriteria decision making(MCDM)techniques was developed to help TBM designers in the process of determining the cutter size.The analytic hierarchy process(AHP)and matter element analysis were applied to obtaining the weights of the cutter evaluation criteria,and the fuzzy comprehensive evaluation and technique for order performance by similarity to ideal solution(TOPSIS)approaches were employed to determine the ranking of the cutters.A case application was offered to illustrate and validate the proposed method.The results of the project case demonstrate that this method is reasonable and feasible for disc cutter size selection in cutter head design.

DESIGN AND FABRICATION OF Si/SiGe PMOSFETs

Based on theoretical analysis and computer-aided simulation, optimized design principles for Si/SiGe PMOSFET are given in this paper, which include choice of gate materials,determination of germanium percentage and profile in SiGe channel, optimization of thickness of dioxide and silicon cap layer, and adjustment of threshold voltage. In the light of these principles,a SiGe PMOSFET is designed and fabricated successfully. Measurement indicates that the SiGe PMOSFET's (L=2μm) transconductance is 45 mS/mm (300K) and 92mS/mm (77K), while that is 33 mS/mm (300K) and 39mS/mm (77K) in Si PMOSFET with the same structure.

Treatment of functional dyspepsia with sertraline:A double-blind randomized placebo-controlled pilot study

AIM:To evaluate sertraline,a selective serotonin reuptake inhibitor in the treatment of patients with functional dyspepsia.METHODS:Consecutive tertiary hospital patients with a clinical diagnosis of functional dyspepsia(FD) according to the Rome Ⅱ criteria with a Hong Kong dyspepsia index(HKDI) of greater than 16 were recruited.Patients commenced enrolment prior to the inception of the Rome Ⅲ criteria for functional dyspepsia.All patients were ethnic Chinese,had a normal upper endoscopy and were Helicobacter pylori negative prior to enrolment.Study patients were randomized to receive sertraline 50 mg or placebo daily for 8 wk.HKDI symptom scores,quality of life,hospital anxiety and depression(HAD) scale and global symptom relief were evaluated before,during and after treatment.Adverse effects were monitored during and after treatment.RESULTS:A total of 193 patients were randomized in the intention to treat(ITT),and 150 patients were included in the per protocol(PP) analysis.In both the ITT and PP,there was no difference in the primary outcome of global dyspepsia symptoms between the sertraline and placebo groups at week 8.In the ITT analysis,98 and 95 patients were randomized to the sertraline and placebo groups respectively.A total of 43 patients withdrew from the study(22.3%) by week 8,with 23 of the 24 drop-outs in the sertraline group occurring prior to week 4(95.8%).In contrast,in the placebo arm,11 of 19 patients dropped out by week 4(57.9%).Utilizing the last response carried forward to account for the drop-outs,there were no differences between the sertraline and placebo groups at baseline in terms of the HKDI,HKDI 26.08 ± 6.19 vs 26.70 ± 5.89,P = 0.433;and at week 8,HKDI 22.41 ± 6.36 vs 23.25 ± 7.30,P = 0.352 respectively.In the PP analysis,74 and 76 patients were randomized to the sertraline and placebo groups respectively.At baseline,there were no statistically significant differences between the sertraline and placebo groups,HKDI 25.83 ± 6.313 vs 27.19 ± 5.929 respectively,P = 0.233;however by week 8,patients in the sertraline group demonstrated a statistically significant difference in their Hong Kong Dyspepsia Index compared to placebo,HKDI 20.53 ± 6.917 vs 23.34 ± 7.199,P = 0.02,respectively).There was also no statistically significant difference in overall quality of life measures or the HAD scale related to treatment in either the ITT or PP analysis at week 8.CONCLUSION:This pilot study,the first to examine sertraline,a selective serotonin reuptake inhibitor,for the management of FD,did not find that it was superior to placebo.

Mixing ratio design of emulsified asphalt cold recycled mixture based on gyratory compaction molding

In order to study the application of gyratory compaction molding method in emulsified asphalt cold recycled mixture and optimize the relevant technical parameters, the study was carried out according to splitting strength, stability and water stability test;the design of the experiment involved changing gyration number, emulsified asphalt and water content, molded specimen temperature and other factors to analyze the volume parameters, mechanical properties and water stability. The results show that both the maximum dry density and dry and wet splitting strength ratio(DWSSR) of emulsified asphalt cold reclaimed mixture are improved by the rotary compacting method, while the porosity and the optimal dosage of water are reduced. Furthermore, with the increase of compaction times, the porosity and splitting strength index both change exponentially. DWSSR and porosity are consistent with quadratic functions. The use of gyratory compaction for 70 times at 25 °C and the optimum dosage of emulsified asphalt can be determined based on the splitting strength ratio. The high-temperature stability and water damage resistance of the pavement can be improved by the use of rotary compacting method effectively, and the early strength and road performance are higher than the regulatory requirements.

Modular Fixture Assembly Model for Virtual Assembly Design

To support modular fixture assembly design in virtual environment,a multi-view based modular fixture virtual assembly model is proposed.Instead of squeezing all assembly related information into a single model,three complementary views of assembly model,element information,function and structure,and assembly relationship are proposed to be used.The first view contains the detailed element information,while the other two explicitly capture the hierarchical function relationships and mating relationships respectively.These views are complementary in the sense that each view only contains a specific aspect of assembly related information while together they include required assembly related information.The proposed assembly model is specialized to accommodate the features of modular fixture virtual assembly design and applied in our developed prototype system.

A Jury-Based Trust Management Mechanism in Distributed Cognitive Radio Networks

In the trust management scheme of the distributed cognitive radio networks, the absence of the central control devices cause many problems such as a lack of standardized control for trust computation, and the absence of the decision makers in trust evaluation and collaborative decision making. A trust management mechanism based on the jury system for distributed cognitive radio networks is proposed in this paper. The "jury user" is designed to collaboratively examine the reputation of the cognitive user in the networks and to perform data fusion and spectrum allocation for distributed cognitive radio networks. Simulation analysis results show that the proposed scheme can ensure accuracy and fairness in trust evaluation and improve effectiveness and flexibility of spectrum allocation.

Dynamic simulation on rubber spring supporting equipment of vibrating screen

By ANSYS, dynamic simulation analysis of rubber spring supporting equipment used in vibrating screen was made. The modal frequency, mode, and harmonic displacement under working frequency were obtained. Variation of rubber spring supporting equipment＇s dynamic performance was discussed first, which is under the condition of existing spring stiffness difference and exciting force bias. Also, the quantitative calculation formulas were given. The results indicate that the performance of vibrating screen is closely related with rubber spring supporting equipment＇s dynamic performance. Differences of springs＇ stiffness coefficients reduce the modal frequency reduced, decrease the dynamic stiffness, and increase vibration displacement. Exciting force bias induces a larger lateral displacement. When rubber springs＇ stiffness coefficients exist, differences and lateral force accounts for 5% in total exciting force; rubber spring supporting equipment＇s side swing is larger than 1 mm, exceeding the side swing limit.

Configuration Synthesis and Performance Evaluation Metrics of Lunar Rover Locomotion Systems

A method of topology synthesis based on graph theory and mechanism combination theory was applied to the configuration design of locomotion systems of lunar exploration rovers(LER).Through topology combination of wheel structural unit,suspension unit,and connecting device unit between suspension and load platform,some new locomotion system configurations were proposed and the metrics and indexes to evaluate the performance of the new locomotion system were analyzed.Performance evaluation and comparison between two LER with locomotion systems of different configurations were analyzed.The analysis results indicate that the new locomotion system configuration has good trafficability performance.