Mechanical properties of MgO–Al2O3–SiO2 glass-infiltrated Al2O3–ZrO2 composite

This work attempts to improve the mechanical properties of alumina-10 wt% zirconia (3 mol% yttria stabilized) composite by infiltrating a glass (magnesium aluminum silicate glass) of lower thermal expansion on the surface at high temperature. The glass improved the strength of the composite at room temperature as well as at higher temperatures. There was a significant improvement in the Weibull modulus after the glass infiltration. Glass-infiltrated samples showed better thermal shock resistance. The magnitude of strength increment was found to be in the order of the surface residual stress generated by thermo-elastic properties mismatch between the composite and the infiltrated glass.     

A neural-network method for the nonlinear servomechanism problem

The solution of the nonlinear servomechanism problem relies on the solvability of a set of mixed nonlinear partial differential and algebraic equations known as the regulator equations. Due to the nonlinear nature, it is difficult to obtain the exact solution of the regulator equations. This paper proposes to solve the regulator equations based on a class of recurrent neural network, which has the features of a cellular neural network. This research not only represents a novel application of the neural networks to numerical mathematics, but also leads to an effective approach to approximately solving the nonlinear servomechanism problem. The resulting design method is illustrated by application to the well-known ball and beam system.     

基于PLC的模糊参数自整定冷库控制系统研究

针对冷库制冷系统大滞后、大惯性、时变性的特点，提出基于PLC的模糊PID参数自整定控制算法。该技术既充分利用了PLC的软硬件资源，又提高了控制的智能化程度。模糊PID技术与变频技术相结合应用于冷库制冷系统，实现了压缩机的变频调速，有效地节约了能源，提高了经济效益。     

Committee Report-recommended Practice on Specific Aspects of Cable Installation in Power-Generating Stations

In the late 1940's high voltage pipe-type feeders were first installed in the United States. Since that time, over 2360 circuit miles of underground high voltage pipe-type cables have been installed throughout the country. Con Edison has approximately 652 circuit miles of high pressure pipe-type cable on its system, operating at 69, 138 or 345 kV. The typical pipe-type cable system is comprised of a steel pipe, containing 3 cables, with splices located at intervals of approximately 2000 feet. The pipe is filled with dielectric fluid which is maintained at a nominal operating pressure of 200 psig. Pressurization on the feeder is maintained automatically by pumping plants. For the 345 kV system, these plants sometimes include cooling capability. As the pipe type cable system grows older, leaks of dielectric fluid develop. The major causes of leaks are corrosion, contractor damages, effects of stray currents and localized pipe wear due to vibration. Quick detection and location of dielectric fluid leaks, particularly without the need to deenergize the feeder, is of prime importance to the utility industry. Raychem Corporation has been involved with the development of sensor cables for the detection and location of fluid leaks such as water and gasoline. This technology has been enhanced to address the problem of pipe type cable dielectric fluid leaks and a new system has been developed. The new system uses a sensor cable which is buried in the trench with the pipe type cable.     

Shrink‐Wrapped Boundary Face Algorithm for Mesh Reconstruction from Unorganized Points

A new mesh reconstruction scheme for approximating a surface from a set of unorganized 3D points is proposed. The proposed method, called a shrink‐wrapped boundary face (SWBF) algorithm, produces the final surface by iteratively shrinking the initial mesh generated from the definition of the boundary faces. SWBF surmounts the genus‐0 spherical topology restriction of previous shrink‐wrapping‐based mesh generation techniques and can be applied to any type of surface topology. Furthermore, SWBF is significantly faster than a related algorithm of Jeong and others, as SWBF requires only a local nearest‐point‐search in the shrinking process. Our experiments show that SWBF is very robust and efficient for surface reconstruction from an unorganized point cloud.     

An algorithm for region filling using two-dimensional grammars

Interior-defined regions, flood-fill algorithms, and a simple 4-connected region filling algorithm are presented together with their properties. an algorithm for region filling using two-dimensional grammars is also presented together with illustrative examples. the results obtained in this article may have useful application in intelligent systems, computer graphics, artificial intelligence, expert systems, knowledge engineering, pattern recognition, pictorial databases, and related areas.     

A quantification of link budget differences between the cellularand PCS bands

The median propagation loss in the personal communication services (PCSs) band (near 1.9 GHz) is generally recognized to be 9-10 dB greater than that in the cellular band (near 850 MHz). It would be highly desirable to make up this deficit in order to minimize the infrastructure cost of PCS service startup. This goal is aided by three factors favorable to operation at PCS frequencies. First, the vertical pattern gain of the base-station antenna, for the same size, will be more than 3 dB higher at 1.9 GHz. Second, the gain derived from using base-station antenna diversity on the uplink will be greater at 1.9 GHz. The third factor is lower man-made noise at 1.9 GHz, especially in urban areas. We have carefully examined all these factors in order to quantify the link budget differences between the two bands for three types of environment, namely, urban, suburban, and rural. We find that link budget parity (meaning the same allowable cell sizes) can be achieved in all three environments with fairly modest remedies. These include the use of tower-top electronics and minor increases in downlink power. An alternative remedy is to use four-branch maximal ratio combining (MRC) at the base station, which would provide a natural transition toward the deployment of adaptive arrays     

坚持以人为本 探索创新型水利人才培养机制

水利事业又好又快发展取决于创新型人才的开发与使用，因此，研究加快培养创新型水利人才是当前一个重要的课题。论述了水利行业人才内涵与特征，介绍了水利部创新型水利人才培养的实践与探索和取得的成效以及我国水利人才目前的结构，分析了水利部在创新型水利人才培养方面存在的不足之处。针对我国在水利人才方面存在的总量规模较大而高层次人才相对不足，人才知识和能力技术技能单一、专业知识面较窄，人才学历偏低等问题，提出了继续改进水利人才培养机制的建议。     

Eigenvectors of tridiagonal matrices of Sylvester type

Eigenvectors of the tridiagonal matrices of Sylvester type are explicitly determined. These are closely related to orthogonal polynomials named after Krawtchouk, (dual) Hahn and Racah as well as to q-Racah polynomials.