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A compact two-dimensional angle sensor with a measurement resolution that exhibits superior sensitivity has been designed based on the autocollimator principle to enable the precision measurement field to measure the pitch and yaw error motions of a moving object. The signal drift of this sensor affects the measured angle and is mainly caused by the change in environmental temperature. To improve the thermal stability of the sensor, computer simulation has been conducted using the finite element analysis software ANSYS 16. Simulation results show that the angle sensor is considerably stable to adopt mechanisms with a symmetrical structure. Thus, a modified optimal angle sensor is developed, and its thermal stability has been verified via contrast experiments. Compared with the original sensor, the average drift of the optimized angle sensor is reduced from 0.430 arcsec∕°C to 0.120 arcsec∕°C when the variation of the environmental temperature is 5 °C. The optimal angle sensor is ideal for high-precision measuring equipment.

By using the AUTODYN, the study of numerical simulation on pressure field characteristics of underwater explosion detonated by the double explosive sources at the same time shows that a coupled zone with increased pressure appears after the two initial shock waves transmit through each other and at the intersection of the two initial shock waves, the mach wave appears. The transmitted waves diffract around bubbles with a reflected rarefaction wave. The peak pressure in the central area between the two explosive sources is caused by transmitted wave and has dishing isosurface. And the peak pressure outside the two explosive sources is caused by initial shock wave and has spherical isosurface. Coupled peak pressure in the plane of symmetry is two times more than incident peak pressure and with the propagation of shock wave, the ratio of coupled peak pressure and incident peak pressure gradually increases.

A series of studies, including structure layout, detail design, material test, construction technology and prototype monitoring, etc are performed for the cofferdam on the left downstream bank of Shatuo hydropower station, which is situated on Wujiang River, Guizhou, China. Based on the research, the hardfill cofferdam with super-sized aggregates and ultralow cement in practical construction is firstly investigated. In which, the maximum aggregate size reaches 70cm and the minimum usage of cementing materials is 50 kg/m3 (25 kg/m3 for cement). According to the results of field detection and prototype monitoring, the implementation effect of the project is objectively evaluated. The research achievements and engineering practice can provide references for the design and construction of temporary cofferdam and low-medium permanent dam.

To deal with the problem that information shares hardly and data exchanges inefficiently in distribution system, various information systems need multi-source integration. The IEC61968-based information exchange platform is an effective means to resolve the integration problem, realizing seamless data exchange and sharing of data between various subsystems. This paper mainly analyzes the Distribution Management System (DMS) information integration architecture and the message structure. Firstly, the paper proposes a design scheme of power Enterprise Service Bus (ESB) based on Service-Oriented Architecture (SOA) which meeting IEC 61970/61968 standards. Meanwhile, by analyzing the message characteristic of IEC61968 standard, introduce a kind of message format which is suitable for the loosely coupled heterogeneous system with application services and integrating and information sharing. The proposed ESB architecture and message format can meet the need of data processing under different business integration scenes, so as to facilitate the information integration of distribution management system.

Cloud computing technology created a brand new approach for further information resources management and utilization. Based on exploring characteristics and applications of cloud computing technology, the study in this paper is focused on cloud service with information resources. The aim of this study is to construct a cloud service model, namely Information Resource as a Service (IRaaS). Our model depicts the components of IRaaS and relationships among those components, which builds up a prime foundation for further studying on both information resource management and service.

The integrated mathematical model of an interior permanent magnet synchronous machine (IPMSM) system is set up suitable for healthy state, open-circuit fault state and fault-tolerant state in this paper. An on-line open-circuit fault diagnosis method is proposed, the fault-tolerant structure is set to connect the fault phase to the middle of DC link, considering that DC link voltage is not balanced, therefore, an optimized adaptive space vector pulse width SVPWM of four-switch three-phase inverters (FSTPI) under DC-link voltage ripple condition is presented to achieve the maximum torque per ampere (MTPA) control and flux weakening control of the IPMSM system under the fault-tolerant state. Based on the abovementioned research, system simulations are implemented and simulation results are given.

With the development of electronic technology, the electronic threats faced by microwave semiconductor devices was increasingly serious.In order to study the electrostatic discharge damage mechanism of bipolar silicon transistors, this paper analyzed the basic physical characteristics of bipolar transistor in electrostatic discharge, such as kirk effect and current crowding effect. Through analysis the human body electrostatic discharge model, established the ESD electric injury model of bipolar silicon transistor. If we knew the production process parameter of devices, we can calculate the ESD damage threshold for designing bipolar silicon device and providing a theoretical basis of parameter optimization. Finally the common ESD damage criterion were analyzed from different angles.

This paper conducts a comprehensive research and discussion on the relevant technologies and manifold learning.Traditional MFCC phonetic feature will lead a slower learning speed on account of it has high dimension and is large in data quantities. In order to solve this problem, we introduce a manifold learning, putting forward two new extraction methods of MFCC-Manifold phonetic feature. We can reduce dimensions by making use of ISOMAP algorithm which bases on the classical MDS (Multidimensional scaling). Introducing geodesic distance to replace the original European distance data will make twenty-four dimensional data, which using the traditional MFCC feature extraction down to ten dimensional data.

In order to satisfy the transmission of mass data volume of on-board time delay integration charge coupled devices (TDICCD) image, a high speed image transmission system of space panchromatic TDICCD camera with a large field of view is designed in this paper. A 4- channel parallel high speed transmission system for 16-channel CCD image was designed. A high speed serializer TLK2711 is applied to send and receive multi channel TDICCD images. A single chip TLK2711 can processing 4 channels image. Experimental results show that the designed transmission system can reliably work. The designed transmission system can meet the application for space TDICCD camera with a large field of view. (2013) Trans Tech Publications, Switzerland.

Gas insulated switchgear (GIS) is the most important equipment in the power system. The partial discharge (PD) is the main detection method for the insulation failure. Especially, for insulation condition assessment, the pattern recognition technology of partial discharge in GIS is the most important. Acoustic detection of GIS PD is the effective method and it has long application history. The acoustic detection method is very suitable for defects detection in GIS, for it has the advantages of on-line detection and easy realization of locating the defects.The PD pattern characteristic is the key factor for the analysis of defect type. The PD pattern characteristics of four typical defects in GIS based on acoustic detection are studied in this paper. The results provide a test basis for the recognition of PD types and a deeper study of the mechanism of PD.

Analyzed the intrinsic relationships between the change of institutions and the evolution of village spatial form under different social background. Through consulting literature and field investigation, analyzed how the change of institutions effect village spatial form.The aims are to provide a reasonable way for the evolution of village spatial form under the background of the changes in institutions.

As the support structures of building for crossing river, piers of bridge and/or aqueduct are generally arranged in tandem along the river direction, the fluid dynamic forces are main lateral loads acting on the Piers. Two-dimensional fluid computations have been performed using LES model to investigate the flows around three circular piers in tandem arrangements at a supercritical Reynolds number, Re =8.76×106. Both center-to-center spaces are L/D=2.6. The flows and fluid-dynamic forces obtained from the simulations are analyzed. The results can provide the basis for the dynamic design of the supporting structures of the aqueducts.

In this paper a radius correction method called 4 points co-sphere and simulation for rotor measurement are discussed. The error of rotor end profile after compensation is evaluated by approaching the minimum zone condition successively. Normal vector bound method determines the theoretical curve segment, searching theoretical corresponding point with dichotomy. The evaluation results have shown that the radius correction method of 4 points co-sphere can be used in rotor measurement, and have more applied value in project.

The small-deflection response of a free–free beam subjected to a local uniformly distributed impulsive load at one free end is examined; the material of the beam is assumed to be rigid and perfectly plastic. Solutions are obtained for various combinations of the magnitude and length of the local uniformly distributed impulsive load. The location of the plastic hinge on the beam depends not only on the magnitude of the load but also on the length of the load applied. As the length of the applied uniformly local distributed load is fixed, the plastic hinge would occur in the region between the limit position of plastic hinge εlim and the critical position of plastic hinge εc which are determined by the length of the applied load.

In the field of robot vision, edge feature based stereo matching algorithm can reconstruct the targets with clear contours, which needs accurate and continuous target edges been extracted. In the paper, the smoothing filter operator was designed based on the discrete criteria of edge extraction and its correspondence optimal linear filter. Edge extraction was carried out incorporated the nonmaximum suppression and two thresholds techniques. The discrete criteria based multi-scale edge extraction method was studied with full use of the multi-scale character of the edge information. The detected multi-scale edges were synthesized to obtain the accurate and continuous single pixel wide edge. Then an edge feature based stereo matching algorithm was proposed to obtain 3D information of target. The experimental results demonstrate that the method can effectively suppress disturbance in outdoor environment and reconstruct target contour clearly.

Nickel-based super alloy GH4169 has been widely used in aerospace industry because of its good mechanical properties under high temperature. However, it is difficult to machine for its high strength, poor thermal conductivity and serious work-hardening. The effects of tool geometric parameters on tool life are studied by machining experiments using YG8 tools with different cutting edge angle in this paper. The tool with cutting edge angle 45°has longer tool life than 75°. The cutting experiments have been carried out using TiAlN (PVD) coated tools (AC520U) with different rake angle. It shows that the tool life with rake angle 9° were increased by 50% and 25% compared to tool with rake angle 3°and 6° when cutting speed is 30m/min. The tool with rake angle 9° is not suitable for cutting GH4169 when cutting speed is more than 35m/min. The results show that geometric parameter of cutting tool is one of the important factors affecting tool life.

A new style micro-force sensor based on a 3-RRR parallel micro-motion stage which had been researching recent years was introduced in this paper. The sensor can be used in micro-force and micro-torque detection in precision engineering. The result and experience from 3-RRR micro-motion stage research bring this new idea. In the first place, the branched chain structure in motion stage needs to be simplified and improved to adapt to the requirement of sensor. Secondly, a mechanics model is constructed according to the sense organ structure. The Jacobin Matrix which is the most important matrix on parallel structure is analyzed and deduced. The relationship among key dimension is worked out through isotropy parameters. With the theory analysis, the final structure of sense organ is determined. The elastomeric sensor body was pasted with electrical-resistance strain gauges, after it was manufactured by Wire-EDM. Strain gauges employed Wheatstone bridge and amplifier AD620 to produce measuring data. Experiment has indicated that the new sensor is competent for micro-force detecting in X, Y direction and micro-moment around Z direction with high stability and reliability.