一起电机软起动器调试争端的原因分析和解决处理

官地水电站竹子坝人工骨料生产系统由水电八局承建,其细碎设备供电电源电气设计、施工采用总承包方式,但细碎设备电机的软起动器由业主采购,供货厂家美卓公司负责软起动器的选型设计和安装调式.在调试过程中出现了少见的故障现象,引发了美卓厂家和水电八局之间长达两个多月的争议.对故障原因进行了仔细分析,提出了详尽的解决处理方案,并由此对工程建设管理作出了深层反思,单对其他工程建没有一定的借鉴意义.     

隔河岩电厂机组转速测量配置及其应用策略

准确、可靠的转速信号采集是机组安全稳定运行的重要因素,是调速器调节品质的重要保证。通过对隔河岩电厂转速测量装置的配置及应用进行了详细的分析。     

“实战”型模拟法庭在高校法学教学中的个案应用

按照“实战”型模拟法庭教学的特点和运行步骤，选用适当的案例，组织学生进行“实战”模拟审判，对其进行个案分析，具有一般意义上的指导作用。     

Near-Horn Prolog and beyond

Near-Horn Prolog is an extension of Prolog designed to handle disjunction and classical negation. The emphasis here is on minimal change from standard Prolog in regard to notation, derivation form, and speed of inner-loop computation. The procedure is optimized for the input program that is near-Horn; i.e., a program where almost all clauses are definite clauses. This paper goes beyond the near-Horn focus to report on the completeness of one version of nH-Prolog, along with soundness of the procedure. Completeness is important here not only for the usual reasons of guaranteed success on small problems and insight into the behavior of the procedure but also because we anticipate the introduction of negation-as-failure which requires conviction that a proof will be found if a proof exists.This research was supported in part by the U.S. Army Research Office under grants DAAG29-84-K-0072 and DAAL03-88-K-0082 and by NSF Grant IRI-8805696.     

某输出齿轮的冲击有限元分析

对一个承受冲击载荷的输出齿轮建立了两种有限元模型，并分别进行了静态、冲击及瞬态动力学的研究，通过比较可知，冲击载荷的危害是静态载荷的数倍。为齿轮的合理设计提供了依据。     

A universal velocity profile generation approach for high-speed machining of small line segments with look-ahead

Usually a complex contour-machining program generated by CAD/CAM systems composes a lot of small line segments. The intelligence of look-ahead is key to meeting the demand of high speed and high accuracy in the machining of these line segments. By now most researchers just utilize the simplest trapezoidal velocity profiles to deal with the look-ahead problem. Also the number of look-ahead line segments in most commercially available CNC systems is fixed, which cannot make full use of CNC processors. Therefore, a universal velocity profiles generation approach and corresponding optimal look-ahead algorithm based on dynamic back tracking along a doubly linked list are proposed in this paper. Two novel strategies, one for reducing feed rates fluctuation and the other for reducing move errors that come from digital integration and accumulated computation, are also presented. By using the proposed look-ahead techniques, arbitrary velocity profiles having the desired acceleration and deceleration characteristics for the movement of a lot of small line segments can be generated efficiently. Thus, the machining productivity can be dramatically increased without sacrifice of accuracy. The results of simulations and experiments showed the proposed approach was feasible and effective.     

吉利河水库大坝渗流观测资料分析

对吉利河水库粘土心墙砂壳坝的渗流观测资料分析表明，该坝粘土心墙的防渗效果较好，但坝前铺盖没起到防渗作用，且截渗槽较薄弱，渗透比降较大，可能发生渗透破坏。     

卷简内齿轮冷挤压工艺及模具设计

叙述了卷筒内齿轮用冷挤压工艺代替传统的金属切削加工方法的优点，并对卷筒内齿轮进行了工艺分析。介绍了卷筒内齿轮冷挤压工艺及模具设计。     

Generating effective test cases based on satisfiability modulo theory solvers for service‐oriented workflow applications

Web Service Business Process Execution Language (WS‐BPEL) is one of the most popular service‐oriented workflow applications. The unique features (e.g. dead path elimination semantics and correlation mechanism) of WS‐BPEL applications have raised enormous problems to its test case generation, especially in unit testing. Existing studies mainly assume that each path in the control flow graphs that correspond to WS‐BPEL applications is feasible, which always yields imprecise test cases or complicates testing results. The current study tackles this problem based on satisfiability modulo theory solvers. First, a new coverage criterion is proposed to measure the quality of test sets for testing WS‐BPEL applications. Second, decomposition algorithms are presented to obtain test paths that meet the proposed coverage criterion. Finally, this paper symbolically encodes each test path with several constraints by capturing the unique features of WS‐BPEL. These constraints are solved and the test cases (test paths and test data) are obtained with the help of satisfiability modulo theory solvers to test WS‐BPEL applications effectively. Experiments are conducted using our approach and other typical approaches (e.g. message‐sequence generation‐based approach and concurrent path analysis approach) with 10 WS‐BPEL applications. Experimental results demonstrate that the test cases generated by our approach can avoid instantiating idle instance and expose more faults. Copyright © 2015 John Wiley & Sons, Ltd.     

飞机主起落架移动荷载作用下道基动力响应分析

飞机起降过程中主起落架移动荷载引起的跑道道基土体循环动应力是导致跑道沉降和差异沉降的主要原因。采用移动荷载作用下跑道动力响应半解析有限单元法,基于叠加原理分析了B747-400和A380-800客机主起落架轮组移动荷载作用下道基土体动应力响应规律。分析结果表明:在B747-400和A380-800客机主起落架移动荷载作用下,道基浅层土体竖向正应力沿横向呈倒锅底型分布,荷载影响深度可达13 m;主起落架机轮分布对浅层道基土体竖向正应力影响较大,对深层土体影响不大;飞机移动速度对浅层道基土体竖向正应力分布影响较小,但对深层土体影响较明显,当飞机滑行速度达到60~80 m/s时,荷载影响深度达静力分析时的1.5~1.7倍;采用柔性道面板时,浅层土体竖向正应力较刚性道面结构时增加约50%,荷载影响深度增加约10%。