Study on launch dynamics of the tank marching fire

As an army main battle equipment, it is required that the tank should have high firing accuracy and high first round hit probability during marching. The initial disturbance of the projectile is the premier factor that takes effect on the marching fire accuracy of the tank. And the marching fire accuracy of the tank depends on the launch dynamics behaviors of the tank. In this paper, the launch dynamics theory of a tank marching fire is studied, and its launch dynamics model is established. Based on the transfer matrix method for multibody system(MSTMM) and the automatic deduction theorem of overall transfer equations, the overall transfer equation and the overall transfer matrix of a tank multibody system are deduced; the launch dynamics equations of the tank marching fire are deduced, and the dynamic response of the tank system, the motion of projectile in barrel, the initial disturbance of the projectile and the vertical target dispersion are exactly simulated; meanwhile, the results of simulation are verified by tests. This work provides both theoretical foundation and simulation approaches for improving the marching fire accuracy of the tank.     

上海长江隧道连接通道水平冻结法施工

主要介绍了上海长江隧道连接通道冻结法施工技术,包括冻土帷幕设计、冻结孔布置、连接通道开挖支护、控制冻胀和融沉的措施等,同时对连接通道的主要技术创新措施进行了分析。     

沈阳市浑南新城现代有轨电车工程结构设计

针对沈阳有轨电车项目结构设计进行全面总结,详细介绍大跨库房的结构选型、计算及有关特殊问题的处理;对超长车库进行计算分析,采取预应力及其他施工措施,取得较好的效果;最后介绍正线车站的设计情况,总结施工配合中存在问题,以期为后续设计施工提供经验。     

聚乙烯醇指示剂用于医院污水总余氯的测定

目的 探讨医院污水总余氯测定新指示剂的使用。方法 参考《铁道法规汇编》提供的方法，应用PVA(聚乙烯醇)作指示剂进行余氯测定。结果 对4组不同浓度的样品用淀粉和PVA作指示剂进行测定，浓度分别为7．39、9．51、5．56、12．47和7．43、9．47、5．54、12．51mg／L。结论 PVA(聚乙烯醇)作指示剂，精密度和准确度均满足要求，且稳定性优于淀粉指示剂，故可取代。     

多孔沥青混凝土的水热稳定性能

对多孔沥青混凝土的大空隙结构及其高温多雨的应用环境,指出常规的高温稳定性或水稳定性等指标的单一性,进而提出评价其在水-高温综合作用下的路用性能.借助汉堡浸水车辙仪,对相同原材料、不同级配的多孔沥青混凝土进行试验研究,并与AC-13改性沥青混凝土和SMA-13的试验结果进行分析对比.结果表明,汉堡浸水车辙试验既考虑了水-...     

厂拌热再生沥青混合料生产温度的确定方法

通过测定不同温度的再生沥青粘度,得到再生沥青的粘温曲线,由此确定再生混合料的拌和与碾压温度;通过拌和模拟试验建立了基于热传导的新集料加热温度计算公式．用于控制再生沥青混合料的出料温度．结果可为类似工程提供参考。     

材料、结构和工艺因素对高强度螺栓疲劳性能的影响试验研究

对影响高强度螺栓疲劳性能的材料、结构和工艺等因素进行了较广泛的对比试验研究。比较了6种材料疲劳试样的疲劳性能;考察了硬度、再回火、去应力退火、表面脱碳、滚丝/磷化的先后顺序、头下圆角粗糙度、滚丝轮螺纹牙形、头下圆角过渡形式等因素对高强度螺栓疲劳性能的影响。     

HX_D1B型机车大螺栓的强度及预紧分析

文章介绍了HXD1B型机车大螺栓的安装结构及其作用,对大螺栓的轴向工作载荷、预紧力、强度等进行计算和校核,比较了力矩法、测量螺栓伸长法、应变计法等三种不同的预紧力控制方法的优缺点,提出影响大螺栓预紧力控制的各种因素并进行分析,最终确定适用于大螺栓的预紧力及其相应的控制方法。     

Tool sequence optimization based on three logical modes of robot control via CPLEX optimization

Cluster tools have advantages of shorter cycle times, faster process development, and better yield for less contamination. The sequence of dual-arm cluster tools is a complex logistics process during the semiconductor production. Efficient use of cluster tools is naturally very significant to competitive fab operations. Generating an optimized sequence in a computationally efficient manner and assessing the quality of the requirements to improve the fab production are the key factors for semiconductor manufacturing productivity. The Petri net modeling is introduced to minimize the makespan of the process for the three different logical modes and select a better mode after comparing the makespan among the three logical modes. The tool sequence optimization problem is formulated as optimization firing transition sequences based on the Petri net and then the formulation is converted to be linearly solved by the branch-and-cut method in the standard commercial solver CPLEX. Special methods for the linear conversion are highlighted. Due to the limited calculation time requirement for the real production and the large scale of the problem, special methods for the efficiency tuning are applied according to the characteristics of the problem. Numerical testing is supported by one of the most advanced semiconductor enterprises and the computational results show significant improvement compared with the traditional manual sequence results.     

Poisson noise removal based on nonlocal total variation with Euler’s elastica pre-processing

An enhancement-based Poisson denoising method for photon-limited images is presented. The noisy image is firstly pre-processed for enhancing incomplete object information, and then it is denoised while preserving the restored structural details. A variational regularization model based on Euler’s elastica (EE) is proposed for image enhancement pre-processing. A nonlocal total variation (NLTV) regularization model is then employed in the second stage of image denoising. The above two optimization problems are solved by the alternating direction method of multipliers (ADMM). For Poissonian images with low image peak values, experiments demonstrate the validity and efficiency of the proposed method for both restoring geometric structure and removing noise.