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Most indoor substations adopt oil-immersed transformers as voltage transformation device. In multiple disadvantage conditions, the flammable gases formed form transformer oil may explode in transformer room. Typical 220kV main transformer room of indoor substation was researched in this paper. An correlation of pressure relief area of the 220kV mail transformer room of indoor substation were presented based on the CFD tool FLACS modeling of the general designing schemes of the State Grid Corporation of China. This research may be used as reference of the pressure relief technology for main transformer rooms of indoor substations.

To study ball bearing motor working principle, an ingenious experiment was self-designed, which results indicated that the nature for driving torque of the ball bearing motor was thermal expansion rather than electromagnetic force as generally considered. Furthermore, the threshold current and cutoff temperature for the ball bearing motor were found in our experiment.

Double Helix Resistor (DHR) can be used to establish AC resistance standard. Because the short-term stability of the DHR is very important during the process of quantity value dissemination, the DHR should be kept in a temperature-controlled environment. This paper presents a Fuzzy-PID temperature control method based on MSP430F149, the overshoot and adjustment time of the temperature control system can be reduced by using the Fuzzy control rules to adjust PID parameters. A special resistance box is designed to place DHR and decrease the exterior EMI effectively. At last, Fluke 8508A is used to measure the resistance of DHR. The measurement results show that the short-time relative stability of DHR is enhanced to 3×10-7after applying the presented temperature control system.

In order to support characters of data acquisition system of smart grid, such as scalable and plug and play, one configurable node of sensor network was proposed. The number of protocol standard, the number of interface of each protocol standard, the number of senor of each interface and the number of byte of each sensor can be configured in this node. All these parameters can be configured according to the specific application of smart grid and then achieve the best balance between cost and performance. One real model was implemented by VHDL and the number of protocol standard, the number of interface of each protocol standard, the number of sensor of each interface, the number of byte of each sensor can be configured in the range from 1 to 8. The correctness and validity of this real model were confirmed by simulation results of configurable level and one application instance.

This paper proposes a new method of harmonic energy measurement based on atomic decomposition algorithm. Firstly, the matching pursuits (MP) algorithm is introduced and harmonic atom dictionary is designed according to the characteristics of signals to be analyzed to improve the effect of signal decomposition. Then, the MP algorithm is optimized by particle swarm optimization (PSO) to reduce the calculation amount. The simulation results of active harmonic energy in steady and unsteady state demonstrate feasibility and accuracy of the presented method.

Microbiological corrosion to the aircraft fuel system caused by microbial growth and reproduction in aviation fuel may also lead a serious safety risk to aircraft. Categories of microorganism in aircraft fuel tanks,reasons and protection methods of microbial corrosion were summarized and the research of microbiologically influenced corrosion protection which connected with quaternary ammonium germicides was prospected in this paper.

Defects in the specimen of missile engine shell was detected by thermal wave image technology in this paper. In order to gain intuitionistic and accurate space structure image of the detected object, subtracting background and high-frequency emphasized filtering method were used to enhance the image quality. Then the defect was segmented from the background using particle swarm fuzzy clustering algorithm, while the defect size and depth were identified quantitatively. On this basis, 3D reconstruction of the defect by thermal wave image was recognized by Volume Rendering method. The results show that the precision of the defect quantitative identification is higher, and 3D reconstruction result is well, which help us to observe the location and size of defects intuitionisticly.

The pre-processing method of blind source separation based on multifactor analysis is proposed to solve the blind source with noise. Firstly, the shortcomings of existing methods of blind source separation are point out after analyzing their principles. The multifactor analysis is introduced in blind source separation and the maximum likelihood estimate based on expectation maximum is used to estimate the common factor and random error. Finally the FastICA algorithm is used to separate BSS result. The validity and the advantage of this method are illustrated by an example.

This paper analyzed the advantages and disadvantages of existing heat flux sensor calibration methods, proposed a calibration method of thermal heat flux sensor based on wireless sensor networks. Experimental results showed that the detection error was reduced from 6% to 2% after calibration. The proposed method has many advantages, such as short calibration time, accurate results, easy installation as well as batching calibration. In a word, this method is available to calibrate heat flux sensors and will have an important significance for accurate measurement of heat flux.

With the development of information technology, especially the rapid development of network transmission technology, remote monitoring is becoming more and more popular, remote monitoring system (RMS) for CNC machines will be a trend in the control field. This paper introduces research and application status of RMS for CNC machines interiorly and abroad, summarizes its main features,discusses specific technical routes. Finally,problems and suggestions in the development are presented.

This paper study the effects of stress amplitude on the fatigue performance of reinforced concrete (RC) beams strengthened with carbon fibre laminate (CFL). A total of 15 spcimens were tested under three point bending. Three load levels over 60% bending capacity of the strengthened beams with a stress ratio of 0.1 were applied to three groups of five specimens, respectively. The stress amplitudes of groups 2 and 3 are 10% and 15% larger than group 1, respectively. The loads and deflections during the tests were recorded. The fatigue stiffness of the strengthened RC beams with variable stress amplitude was discussed. The experimental results show that the rates of the bending stiffness deterioration of the retrofitted beams, which increase with the load level, under constant fatigue loading are smaller than those under variable fatigue loading.

Evapotranspiration (ETc) is an important quantity for hydrological cycle. This study shows evapotranspiration, the ratio of evaporation to evapotranspiration (E/ETc) of winter wheat and maize in north China. Several relationships, namely, E/ET0 and soil surface moisture, E/ET0 and leaf area index (LAI), are also analyzed. The average seasonal ETc values for winter wheat, maize (2008) and maize (2009) are 431.21, 456.3 and 341.4mm. The value of E/ET0 varied from 1 at initial growth stage to 0.295 at the later growth for winter wheat, and from 1 to 0.492, from 1 to 0.566 for maize (2008) and maize (2009). The relationship between E/ET0 and surface soil water content, and E/ET0 and LAI are fitted to a quadratic parabola equation with significant correlation coefficients, respectively, for wheat and maize. These results should help the precise planning and efficient management of irrigation for these crops in this region.

The paper proposes a Kohonen neural network to the MOA fault diagnosis. The data from MOA monitoring was trained by a Kohonen neural network in Matlab. By this way, the best weight matrix could be obtained. The trained Kohonen neural network is adopted to diagnose the sample, and the MOA fault type could be effectively identified.

Using the wide area information of the IED, the identification faulty components network is constructed based on RBF neural network. Using the state information collected by line IED as the input vector, training samples matrix of identification faulty components network is established to train RBF neural network of faulty components identification, and to test the recognition network using the sample matrix under random failure, and then the faulty line IED can be identified, the faulty components can be determined. Experiments show that the new algorithm based on RBF has higher accuracy rate and better fault-tolerant.

The health of MOVA is very important for power system reliability and insulation coordination studies.MOVA is subjected to different kinds of stresses in services, which will cause degradation at early stage or in the long run.This paper present evidence theory for fault diagnosis of MOVA. Evidence theory can simultaneously analyze information from different sources,draw comprehensive conclusions,reduce single information misjudgment. In this paper, resistive leakage current and infrared imaging make up two types of evidence body for judge. Analysis of experimental data shows that this method can effectively detect early fault of the MOVA.

This paper studied the characteristics of the bimorph piezoelectric vibrator for piezoelectric pump. By simulating the working conditions of the vibration in the pump, we constructed a dynamic model and derived the bending vibration equations of the piezoelectric vibrator under different support conditions. Then the analysis of finite element simulation is carried out for the equations, through which the vibration mode of the multi-order modal of the piezoelectric vibrator was acquired, and the relationship between the deformation deflection and peripheral support stiffness of the piezoelectric vibrator was analyzed. Finally, the deformation of the piezoelectric vibrator was tested. It is found that the test results are consistent with the conclusions of the finite element simulation, which provides a theoretical basis for the optimal design of the bimorph piezoelectric vibrator.

Marine gas turbine exhaust ejector device is responsible for reducing or eliminating the infrared signatures of exhaust system. In order to optimize the structure of exhaust ejector and shorten the cycle of research, it is essential to study the successful experiences on exhaust ejectors by scholars abroad. In this article two structure innovations were introduced: the nozzle structure changing from circular to rectangular and multi-stage diffuser, then a new type of marine gas turbine exhaust ejector was designed. Through simplifying the ejector model, numerical simulation was used to predict the characteristics of both the single-stage ejector and the multi-stage ejector. The result indicates the effects of structural parameters on the performance parameters. This research result has certain reference value for marine gas turbine exhaust ejector structure innovations and performance optimization.

The 5-DOF CNC machine tools motion error, motion space simulation and interference are analyzed. The tool machine dynamic and static interference, trajectory planning are discussed, which realizes the parts manufacturability and processing rationality.

The conventional solution proportioner, which is costly and bulky with complex mechanical structure, can't meet the current requirements of the apparatus, such as miniaturization, high reliability and accuracy. Based on the piezoelectric actuation technique, this paper proposed and developed a solution proportioning technique of large dilution ratio. And on the basis of this technology we produced a physical prototype, in which piezoelectric vibrators are used as the main power units and control parts because piezoelectric vibrators are featured with low cost, compact volume, simple structure, non-pollution and others. The physical prototype can be used to dilute various sample solutions of various proportions for one or more times. (2014) Trans Tech Publications, Switzerland.

This paper presents a digital compensation device based on two multiplying digital-to-analog converters (M-DAC) whose reference voltages are the same standard AC signals. The output of two M-DACs, which is controlled by software coding, are used as the in-phase and the quadrature component through a reverse proportional amplifier and a derivation circuit respectively. Then the four-quadrant compensative signal can be got after the in-phase and quadrature components have been synthesized. The resolution of digital compensation device is determined by the M-DAC, and usually can be reached to 10ppm of the reference voltage. Measurement results show that the linearity of the presented digital compensation device is about 3.7×10-5.

In this paper, roads analysis software bisar 3.0 be used to build an elastic layered system analysis model for cement stabilized macadam base. Different construction methods and structures contact conditions between the layers were comprehensive considered based on the actual pavement structure, in order to analyze the internal stress-strain state of cement stabilized macadam. The results show that interlayer contact conditions is approximately smooth state when cement stabilized macadam base used the traditional two layered construction method, which may occur structural damage between cement stabilized macadam base caused by partial stress concentration. However, the interlayer contact conditions is approximately completely continuous state when used the overall construction methods, and the stress-strain state of cement stabilized macadam can significantly improve by changing interlayer contact conditions. Finally, by changing the construction methods for to change interlayer contact conditions, the stress-strain state of cement stabilized macadam can be effectively improved, and the road performance and service life also be significantly improved.

The oil absorption performances of PBMA, P(BMA-BA), PLMA and P(LMA-MMA) for aviation kerosene and dimethylbenzene were studied. The results showed that PBMA had perfect oil absorption for dimethylbenzene, absorptive ratio of P(BMA-BA) for aviation kerosene was the highest,and PLMA had great oil-absorbing amount for aviation kerosene. Moreover, the kinetic mode of swelling process was discussed and correlative parameter indicated that the oil-absorbing process obeyed the first-order kinetics well.

In order to establish and improve the radiation environment monitoring standard system, to provide technical support for the radiation environment monitoring system, this work first retrieve the radiation environment monitoring standards, and clear the domestic status of the radiation environment monitoring standards. According to environmental Protection Department of the relevant documents and other relevant information, the radiation environment monitoring standards and methods have been accessed , to find the missing items and issues proposed revision of the system requirements. Summarizing radiation environment monitoring national standards, standards of environmental protection industry, the nuclear industry standard, there are 28 standard missing items need to the health industry standards, inspection and quarantine industry standards, a total of 145 of these standards of environmental radiation monitoring, radiation monitoring of pollution sources, emergency response and early warning and monitoring from a management and technology meet the basic needs of the radiation environment monitoring. Research found that the standards in the revised 57 and in the formulation of 47, develop. After the revision of China's standards system will be further improved. The radiation environment monitoring work will be further strengthened.

The paper focuses on the resistance characteristic of a novel M-beam separator. Adopting the combination of experiment study and numerical simulation, we achieve that 2D simulation has the similar results as 3D in predicting resistance characteristic which provides the theoretical basis for next research. An M-beam separator model ten times larger than original one based on similitude principle was made for sake of flow field visualization research. The paper analyses flow field distribution of the amplifying M-beam separator by silk thread display technology and the experiment results are well consistent with 2D numerical simulation. The flow field distribution described here could serve as a reference for developing M-beam separator.

Laterite has high void ratio, low density, high moisture content, high plasticity, but it does not match with their physical nature, which has the relatively high strength and low compressibility. In order to improve the strength of laterite and increase its compactness, we usually use the method of dynamic compaction in some large engineering projects. Its easy to find that soil compaction degree increased with the moisture content When the content of moisture is low, but soil compaction decreased after reaching the highest. Multiple compaction can effectively improve the maximum dry density and reduce optimum moisture content, but after compaction number is too much that optimum moisture content dont increase obviously.

With continuous developments of the manned space flight and planetary exploration missions, a new inflatable re-entry aeroshell becomes one of the hot topics of international research. It has the obvious advantages of the easy package, light weight, large resistance area, the low coefficient of ballistic, and the small heat generated by hypersonic air. This vehicle can provide a new way for the emergency return of astronauts, deep space instrumentation and payload recovery. This paper focuses on an inflatable membrane aeroshell with a single loop. Three kinds of cone angle of 75 degrees, 90 degrees and 105 degrees are respectively studied aerodynamic drag. These results show that aerodynamic drag is relationship not only with cone angle but also aerodynamic configuration.

This paper built the two-dimension equivalent model of mega-sub controlled structure system (MSCSS) and mega frame structure, make an analysis of elastic-plastic time history with the different seismic records of observed data. The research of displacement, acceleration and distribution of plastic hinges obtained by the test can illustrate the controlling characteristics of these two structures. The results show that within the elastic-plastic state, mega-sub controlled structural system still have good response control effect; the control effectiveness of the mega frame and sub-structures of the MSCSS is better than that of the mega frame structures.

According to the research status of the public buildings benefit evaluation, this thesis proposes that the evaluation should pay more attention to the comprehensive benefit. On this basis, a new evaluation model for the comprehensive benefit has been constructed by better using FAHP in this field, which has been proved by the Xuzhou Olympic Sports Center project. The research shows that applying FAHP to the public buildings benefit evaluation can make the result more reliable, which has good practicability and application value.

Completed the design of experimental apparatus of magnetic levitation based on ADuC832 microcontroller and discussed the experimental results, the relationship between the forces on permanent magnet and the velocity of non-ferromagnetic conductor can be measured with strain gauge position sensor and photoelectric sensor. A magnet can be non-contact driven to rotate around its central axis by moving conductor, the relationship between the rotational speed of permanent magnet and the velocity of conductor can measured with bias circuit, verifying the correctness of the theoretical analysis. The experimental apparatus of magnetic levitation is well applied in experimental teaching.

The research about electromagnetic emission (EME) during rock failure is very important to earthquake prediction and mine safety. A corresponding monitoring system has been developed according to the characteristics of EME signals during rock fracture, which include a wide frequency band and small amplitude of the inductive signals. The system is constituted by electromagnetic induction probe, signal-conditioning circuit and a computer for data acquisition. Among them, the electromagnetic induction probe can detect spatial magnetic field changes in a certain direction and convert it into electrical signals, the signal-conditioning circuit can magnify, filter and isolate signals acquired by the probe, and the computer for data acquisition is used for recording and displaying the detected signals. Several testing results have been achieved in rock failure experiments on marble that are carried out both by mechanical loading and expansion caused by chemical agents.

This paper presents a current comparator based four-terminal impedance bridge for quantity-value dissemination of national AC resistance standard in China. In order to enhance the feedback adjustment ability and simplify the balance process, the bridge applies a frequency selective amplifier instead of feedforward and feedback networks to balance the magnetomotive force of the current comparator. The resistance difference between the measured and standard resistor can be calculated according to their voltage difference indicated by a digital lock-in amplifier. The AC/DC resistance relative differences between Double Helix Resistor and Tinsley standard resistor are measured with the proposed bridge under 1592Hz.

This paper proposes a game-based model to conduct the issue of road congestion pricing. The ride comfort of travel modes, e.g., cars or buses, is introduced into the travel cost function of the traditional bottleneck model. Furthermore, based on different travel cost functions of various travel modes, the Nash equilibriums are achieved among the government and various travelers. The results can be employed to describe internality and externality of traffic system respectively. Finally, numerical examples are presented. The findings of our work indicate a relationship between the government’s goal and the charge rate and that the emergence of ride comfort obviously is a key determinant of travelers’ behavior.

Dynamic testing of an inflatable beam has been performed to evaluate structural natural frequencies and modal damping ratios. The inflatable beam has a pattern of six composite fiber strips inside thin-film structure that increases its local stiffness that the structure can be self-supporting in the gravity environment when the internal pressure is released. A measurement setup was installed, and the dynamic testing was performed in this self-supporting state. Dynamic characters of the beams were tested with internal pressure or not when the beam had a 2.0kg mass on the top. Moreover, the dynamic characters before rolled up were contrasted to one after. The experimental results indicate that the self-supporting inflatable beams had better bending stiffness, and the curl folding process had an impact on the dynamic characteristics of the inflatable beam. The pressure affection is not obvious on dynamics of the beam.

The high oil-absorbing resin is a new type functional polymer material. The recent development of high oil-absorbent resin and its properties and synthesis were introduced in this reviewpaper. The absorption principle and process of highoil-absorbent resin are also presented. The effect of monomer, crosslinking agent and pore forming agent on high oil-absorption properties of oil-absorbing resin is investigated. At last, the present applications of the high oil-absorbing resin in environmental protection and other industrial purpose are also mentioned.

In order to solve the long span problem of mega-beam, arranging additional columns in MSCSS(Mega-Sub Controlled Structure System).Calculating vertical displacement and acceleration response of the mega-beam,which under vertical seismic, in order to discuss the mega-beam dynamic response that changing location, quantity and contact type of the additional columns. The results shows that: additional columns arranged in the middle of mega-beam , controlling the mega-beam vertical dynamic response is better; compared to the number of additional columns,the location of additional columns has a greater effect on controlling the mega-beam vertical dynamic response; contact type of additional columns has a little effect on controlling the mega-beam vertical dynamic response.

Aims at the safety problems caused by corrosion under coating for it can not easily be observed, specimen of corrosion damage under coating was made for the research of detection by applying infrared thermal wave technology. The surface temperature distribution infrared thermal images were captured, also the surface temperature history of corrosion area, non-corrosion area and their difference. Analysis of test results show that the infrared thermal wave technology is an effective tool in detecting corrosion damage under coating, there has a fine detection time used to estimate the coating thickness, and the position and sizes of defects can be found out directly by the hot spots in the infrared images. The damages can be quantitatively recognized by images processing, but surface uniformity of the specimen has great impact on the damage identification.

WC steel-bonded cemented carbides were prepared by microwave sintering through ball milling, press forming and sintering with iron powders as the matrix, WC particles as the reinforcements. The effect of WC contents on microstructure and properties of steel-bonded cemented carbide was studied. The results show that the steel-bonded cemented carbide sintered at 1280 °C is considered as a liquid phase sintering and Fe7W6, Fe2W2C and Fe6W6C new phases are generated during the sintering process. The relative density, microhardness and bending strength of the steel-bonded cemented carbide increase with increasing the WC contents. Moreover, the mechanical properties of steel-bonded cemented carbide are obviously improved after heat treatment.

For the disadvantages of the traditional NDT methods for coating defects, Thermal Wave Nondestructive Testing (TWNDT) technology was used to detect coating debonding defect on composite Materials matrix. Numerical simulation method was used to simulate the heat transfer process of thermal wave in the coating material with defects. The factors influencing the testing sensitivity were in-depth studied, including the debonding defect size and coating thickness. Simulation results show that: TWNDT technology can quickly and efficiently identify the size of the coating debonding defects, while the thickness of the coating is an important factor influencing the inspection sensitivity for the thermal wave detection.

Plates and shells are well used in structures. In order to study the nonlinear stability of plate, the total potential energy expression was deduced after analyzing the geometrical conditions of four ends simply supported rectangular plate on large deflection, the cusp catastrophic model of the rectangular plate was established based on catastrophe theory, and the bifurcation set that makes the system unstable was obtained to analyze the instability conditions of rectangular plate. The instability conditions of rectangular plate were analyzed based on this set, the critical inner stress is at the cusp point, the necessary condition of instability is σ>σcr, but the plate is stable when the movement path of control variables composed by inner stress and landscape load not across the bifurcation curves in the control space. Structures in some projects can be predigested to such a rectangular plate and this cusp catastrophic model can be used for analyzing its instability conditions for taking preventive measures.

As new generation of solid-state lighting source with green environmental protection, White LED has become the focus of attentions. Along with the development of high power LED, heat dissipation problems of LED become more and more important. This paper makes research on single-chip high power LED by ANSYS finite element software, and analyzes the thermal effects of parameters on the radiator. This paper believes that the influence of radiator materials’ thermal conductivity is not obvious, and the finned height and cooling area of radiator play an very important role in reducing chip junction temperature.

Based on the method of separation of wind speed and direction variable, considering the wind direction frequency function, ascending order to calculate the probability of the actual distribution of the sample, extreme type Ⅰ (Gumbel) and three parameters of extreme type Ⅱ (Frechet) and extreme type Ⅲ (Weibull) probability distribution to fit the sample, this paper has analyzed the weather station observations of 34 consecutive years of the joint distribution of wind speed and direction near to a huge bridge, gained the basic design wind speed in different directions, comparatively analyzed the impact of the sampling interval of change on the basic wind speed as well. The results shows: wind speed in different directions at the same location or different sampling intervals samples of the wind speed sample may be subject to different types of extreme value distribution, should separately fitting; different wind direction frequency of extreme wind speed occurrence and the basic wind speed there are certain differences, taking into account the joint distribution of wind speed and direction is necessary to determine the design basic wind speed of the bridge, and will be conservative without considering the joint distribution; for the same sample wind speed matrix, the shorter the sampling intervals, the optimal distribution of the higher probability model fitting precision, the smaller the basic wind speed, the more economic and reasonable the results.

Traditional pulse infrared thermography uses a single pulse with high energy to heat the specimen. For deeper or smaller defects, more energy must be conducted into the specimen to improve the detectability, which also may cause thermal impact damage in particular for composites. Consequently, multi-pulse heating was presented in this study to solve the problem. The multi-pulse is based on heating the materials with two or more pulses separated by a proper time. In this way, more energy can be conducted into the object as well as every pulse thermal impact was separated. Simulation results show that multi-pulse method can not only enhance the defect detectability several times but also is effective to avoid thermal impact damage by restraining the maximum temperature. Ultimately, the optimum separation time for multi-pulse was chosen according to the best inspecting time of single pulse which was estimated by a very simple method.

The infrared thermal wave technology is a new nondestructive testing (NDT) method with a kind of advantage, including non-contact, intuitionistic, fast et al. But the infrared images always have defects that the low-contrast and high-noise due to uneven brightness and calefaction in the testing process, which enhance the difficulty of following quantitative distinguishment of defects. Therefore, the improved homomorphic filtering is given in this article. The detailed processes of the method and testing results are given. The results of the experiments show that the method has higher peak signal to noise ratio (PSNR), can improve image quality, which establish basis for future research of image segmentation.

In this paper, the impacts of environmental vibration on precision instruments as well as the vibration allowances of precision instruments are introduced firstly. Then the integrated model of a high-rise building is established, and the vibration responses of the floor where a precise instrument is fixed are calculated by inputting micro-vibration loads. The passive control method is used by putting several lead rubber bearings at the bottom of instrument and at the bottom of building separately, and the isolated vibration responses are calculated and analyzed. Some valuable conclusions are obtained by comparing the vibration responses of isolation system and non-isolation system with acceptable values according to the environmental vibration codes for precise instruments.