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A RF received signal strength indication (RSSI) circuit with 100MHz to 2.5GHz frequency bandwidth was designed based on Jazz 0.18 μm SiGe HBT process. The RSSI was composed of 4 cascaded limiting amplifier and full wave current rectifier. A novel DC offset compensation circuit was adopted to achieve stable operating point. The circuit was simulated with Cadence design kit. Results showed that the RSSI had a wide dynamic range from 45dBm to 0dBm, operated at a 3.3V single supply. The power consumption is 18.8mW.

Wax precipitation of oil production wells seriously influence the oil production. In order to improve the level of wax removal, it is necessary to predict the depth, thickness and period of wax precipitation in the wellbore with oil production. On the basis of the mechanism analysis for wax precipitation in the wellbore, the theoretical model and empirical model were built up and programmed wax precipitation of oil production wells software and the results by the two models were compared. The sensitive factors which influence wax precipitation in the wellbore were analyzed. The results show that the two models can be used to predict the wax thickness, depth and precipitation cycle. The empirical model for wax precipitation profile prediction is more accurate than the theoretical model. The wax precipitation varies with the productive time and water cut.

For an air-to-air cooled medium motor, to ensure the cooling effect of the motor, the physical model of the motor cooling air inside the cooler was built. By the finite volume method according to the computational fluid mechanics (CFD) principle, the three-dimensional turbulent flow field in computational domain was simulated numerically using boundary conditions of the inlet and outlet obtained from engineering calculations. From the result, the thermal field of cooler was calculation. Finally, through the comparison, the cooler cooling the motor cooling effect sufficient play , the outer duct can effectively reduce the internal temperature of the cooling gas duct , the air duct outside the cooling gas declined about 35 °C after cooling the temperature of the air duct, the calculation method is feasible for the motor cooling system design overall foundation .

For a medium air-cooled asynchronous motor, the physical model of cooling air inside the motor was established to research the air flow distribution and characteristics of the internal flow of the medium motor. By the finite volume method according to the computational fluid mechanics (CFD) principle, the three-dimensional turbulent flow field in computational domain was simulated numerically using boundary conditions of the pressure inlet and outlet obtained from engineering calculations. From the result, the thermal field of stator and rotor was calculation. The results show that the wind speed of cooling air duct which near the both ends was higher than the middle. It causes the temperature of the motor which near the both ends was lower than the middle part. The maximum temperature rise of the motor appear in the middle of the upper windings, and the specific value was 74K.

In order to guide the robots for harvesting citrus fruits, method based on normalized RGB model and chromatic aberration map was developed to detect citrus fruits with shadow within tree canopy. Several images of natural citrus-grove scene were photoed, and the color properties of target objects were analyzed. A rule for segmenting citrus fruits from background was put forward by fusing the segmented results of the normalized R channel map and the chromatic aberration map of R and B channels. The results show that the fruits with shadow can be detected integrally using the proposed method.

Horizontal well and hydraulic fracturing are the main technologies for shale gas development. The desorption properties of shales are very important data for shale gas development. In order to simulate the desorption process in shales with horizontal well and fractures, a new method for shale sample preparation and a new experimental system for the evaluation were developed. The effect of the number and half-length of fractures on the desorption rate and the desorption equilibrium time were measured when the system pressure drops from 9.2MPa to 7MPa. Experiments show that the initial desorption rate increases and the equilibrium time decreases with the increase of the number and half-length of fractures. Within the scope of the experiments, the number of fractures is more important than the half-length of fractures for the desorption rate.

When the cylindrical NdFeB magnet was magnetized along the axle wire, the magnetic field around the magnet was symmetric about the axle wire. The output voltage of Hall sensor was proportional to magnetic induction induced by itself. Around the magnet, the magnetic induction component along the axle wire could be measured by Hall sensor. The contour line and contour surface of magnetic induction could be plotted by MATLAB. A sensor array was composed of three Hall sensors in triangular distribution, and 3D Cartesian Coordinate System was established. 3D coordinate of magnet can be measured with this sensor array based on contour surface. Underground soil deformation will change the relative position of sensor array and magnet. The size of geotechnical displacement can be calculated after getting the new 3D coordinate of magnet. Along with dual-axis magnetic sensor based on MR effect, the orientation of geotechnical displacement can be measured, and so able to measure the underground displacement.

This paper gives a method to calculate the temperature rise of the water cooled PM railway traction motor using 3D fluent and thermal field. Building a 3D Finite Element Method (FEM) model of 20kW PM synchronous traction motor, the heat transfer coefficient of each tunnel wall is calculated by fluent field, and then the temperature distribution is got from thermal field. Compared with the experimentation, the precision of this method is verified and some conclusions are obtained.

This paper analyses the stress state of sintered hollow block infilled insulation masonry under practical conditions. Based on the fact that the static loading performance of the new masonry block can be used in masonry structure, the comparative experiment research focused on the seismic performance between masonry works made of the new block and traditional sintered perforated brick with horizontal and vertical load working simultaneously, damage regulars and corrective measures are key points. Results show the mechanical performance of the new block masonry is worse than sintered perforated brick masonry in fragility and vertical loading capability. To get the same mechanical performance, the new block masonry should be improved in rib width, rib number and distance, especially in restraint by construction columns and ring beams.

In order to measure ground surface deformation, a sensor based on cable impedance change is studied in this paper. This sensing cable has elastic double helical structure with much larger measurement range than optical fiber distributed deformation technology. Using the precision impedance analyzer, we obtain the relationship between elongation and impedance of the sensing cable and choose one of the frequent as the measurement frequency. A ground surface deformation measuring circuit is designed for the sensing cable. Deformation experiment shows that the relationship between sensing cable impedance and stretching deformation is approximately linearity, when the deformation is small.

Taking the rockfill dam of Nuozhadu as a example. Through the experiment on excavated softrock-contained rochfill with different deterioration degree, obtained related computational parameters. Useing Pseudo Load Method, compute and analyse effects of softrock-contained rockfill for stress and deformation of high core rockfill dam. Conclude that weathered soft rocks cause mechanical properties deterioration of rockfill, but only increase stress level of corewall upstream face, and destruction zone don't occur. It is feasible that softrock-contained rockfill are utilized in the secondary rockfill zone of high core rockfill dam.

The influences of dispersant type, supersonic time and concentration on the dispersion property of the nano-aluminium powders in glycol water were systematically studied by using Sodium dodecyl sulfate (SDS)，cetyl trimethyl ammonium bromide (CTAB) and sodium hexa metah posphate（SHMP）as dispersants. During the first stage of the experiments, influences of dispersant type and ultrasonic time with these dispersants were evaluated. The next stage of the study was focused on SHMP concentration. The influence of SHMP concentration was assessed. The results show that with the increasing of ultrasonic time, the dispersion property of nano-aluminum powders first increases and then decreases, and SHMP is the best one. The excellent dispersing condition on the dispersion property of nano-aluminium is: 5g/L SHMP and 50 min ultrasonic vibration.

It is an expectation of most of the numerical control products manufacturer that have a powerful controller with whole won intellectual property and without restriction from other companies. The paper introduces a new type of motion controller that based on ARM and EtherCAT field bus. It concludes the analysis and porting method of the EtherCAT soft master source code, and how to modify the driver of dm9000 to make EtherCAT master works correctly. It also gives an example to confirm the reliability of the controller. Since ARM has an open architecture, EtherCAT soft master does not depend on any special hardware card, and Linux OS is an open source system, this controller has open and flexible characteristic both on hardware and software.