高镁瓷工艺特性研究和应用

本文总结了ＭｇＯ－ＳｉＯ２－Ａｌ２Ｏ３系的高镁瓷配方、增塑及烧成工艺特性的研究过程与应用结果；介绍了适应大生产的高镁瓷制作工艺。     

On the boundary-layer control through momentum injection: Studies with applications

The concept of moving surface boundary-layer control, as applied to a Joukowsky airfoil, is investigated through a planned experimental programme complemented by numerical studies. The moving surface was provided by rotating cylinders located at the leading edge and/or trailing edge as well as top surface of the airfoil. Results suggest that the concept is quite promising, leading to a substantial increase in lift and a delay in stall. Depending on the performance desired, appropriate combinations of cylinder geometry, location and speed can be selected to obtain favourable results over a wide range of angle of attack. Next, effectiveness of the concept in reducing drag of bluff bodies such as a two-dimensional flat plate at large angles of attack, rectangular prisms and three-dimensional models of trucks is assessed through an extensive wind tunnel test-programme. Results show that injection of momentum through moving surfaces, achieved here by introduction of bearing-mounted, motordriven, hollow cylinders, can significantly delay separation of the boundary-layer and reduce the pressure drag. The momentum injection procedure also proved effective in arresting wind-induced vortex resonance and galloping type of instabilities. A flow visualization study, conducted in a closed-circuit water tunnel using slit lighting and polyvinyl choride tracer particles, adds to the wind-tunnel and numerical investigations. It shows, rather dramatically, the effectiveness of the moving surface boundary-layer control (MSBC). The Sabita Chaudhury Memorial Lecture The models were fabricated in the Mechanical Engineering Workshop. The assistance of M/s E Abell, P Hurren and D Camp in the design and construction of the models is gratefully acknowledged. The investigation was supported by the Natural Sciences and Engineering Research Council of Canada, Grant No. A-2181.     

ON THE MODELLING OF PARTICLE-BODY INTERACTIONS IN STOKES FLOWS INVOLVING A SPHERE AND CIRCULAR DISC OR A TORUS AND CIRCULAR CYLINDER USING POINT SINGULARITIES

Few exact solutions of the Stokes equations are known, even for steady or quasi-steady flows, involving finite sized bodies, and numerical techniques generally have to be resorted to for finding solutions. However, quite effective modelling of flows involving complicated boundary geometries is possible using the three-dimensional Stokeslet and rotlet point singularities. Two problems are studied in detail. In the first example, exact solutions for the three-dimensional Stokeslet and rotlet placed axisymmetrically along the axis of a circular disc are found and combined with Brenner's first order interaction formulae to determine the effect of the presence of the disc on the force and torque acting on a particle whose dimensions are small compared with its distance from the disc. The results are compared with those of a full numerical integration of the Stokes equations for a sphere translating towards a disc. In the second example, Brenner's first order wall correction theory is applied to the motion of a particle in a circular cylinder using the exact solutions for a torus translating or rotating in isolation. The theoretical predictions for the drag on a torus settling symmetrically in a circular cylinder are compared with those determined experimentally.     

有限缓冲区FMS的特征分析与托盘配置

本文研究了Ｊｏｂ－Ｓｈｏｐ型有限缓冲区ＦＭＳ的运行特性及托盘优化配置问题，给出了系统的分析模型及托盘优化算法。本文的结果对系统的分析与设计具有重要的实际意义。     

柔性纤维混凝土的疲劳特性研究

将柔性纤维掺入水泥混凝土可以大幅度提高混凝土的弯曲疲劳等路用性能,并通过试验建立了柔性纤维混凝土的疲劳方程.结果表明,柔性纤维不但能使混凝土的强度提高,更主要的是可以在重交通条件下,可成倍地提高混凝土的弯曲疲劳寿命.     

An efficient heuristic for scheduling batches of parts in a flexible flow system

Flexible manufacturing systems (FMSs) are a class of automated systems that can be used to improve productivity in batch manufacturing. Four stages of decision making have been defined for an FMS—the design, planning, scheduling, and control stages. This research focuses on the planning stage, and specifically in the area of scheduling batches of parts through the system.The literature to date on the FMS planning stage has mostly focused on the machine grouping, tool loading, and parttype selection problems. Our research carries the literature a step further by addressing the problem of scheduling batches of parts. Due to the use of serial-access material-handling systems in many FMSs, the batch-scheduling problem is modeled for a flexible flow system (FFS). This model explicitly accounts for setup times between batches that are dependent on their processing sequence.A heuristic procedure is developed for this batch-scheduling problem—the Maximum Savings (MS) heuristic. The MS heuristic is based upon the savings in time associated with a particular sequence and selecting the one with the maximum savings. It uses a two-phase method, with the savings being calculated in phase I, while a branch-and-bound procedure is employed to seek the best heuristic solution in phase II. Extensive computational results are provided for a wide variety of problems. The results show that the MS heuristic provides good-quality solutions.     

柳海矿运输大巷返修工程深部软岩支护设计研究

通过现场调查、室内试验以及理论分析,柳海矿运输大巷支护现状进行分析研究,总结破坏原因。根据现场工程地质条件、岩石特性和破坏特点,确定软岩变形力学机制为高应力膨胀性软岩,并提出采用预留刚隙柔层支护技术进行支护。     

蝶阀加工及装配工艺的研究

传统工艺加工阀体、活门时，对机床的性能要求较高，一般为数控镗床。介绍了一种采用普通镗床加工阀体、活门的工艺方法及蝶阀在厂内装配的工艺方法。     

改进的第三代相干算法及应用

在讨论相干技术发展及三代相干算法优缺点的基础上，介绍了改进的第三代相干算法。应用自行开发的相干软件对多个油气勘探和开发区块的三维地震资料进行处理、分析，对相干时窗长度、相关道数等参数对算法效果的影响及相干体对断层、异常地质体的识别，以及解释方法进行了探讨。应用实例证明，改进的第三代相干算法抗干扰能力强，横向分辨率高，不仅适用于倾斜地层，而且对断层尤其对小断层、异常地质体具有较高的检测能力，是油气勘探和开发的一项有效和实用的技术。     

Hybrid of multi-signal processing methods for detection of small objects in containers filled with beverages using ultrasound

Ultrasound backscattered signals for object detection could be too weak to be perceived when superposed to strong reflection signals, and could also be complicated either in time or frequency domain. These peculiarities raise a challenge for signal processing methods. In this paper four signal processing methods were studied to detect objects in containers. Root mean squares (RMS) method was better in object detection but needed to combine other methods to increase detection success rate. Variance, center frequency pressure ratio (CFPR) and backscattered amplitude integral (BAI) methods have similar overall detection ratings. The optimal signal size, to increase the detection ability, corresponded approximately to the length of reverberation signals before it was dissipated.