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Fluoride conversion films were synthesized on cast magnesium alloy AZ31 by immersion in hydrofluoric acid for different days to improve the corrosion resistance of Mg alloys as degradable implant material. The effects of the films on the corrosion behavior of the mg substrates were investigated by immersion tests. The results showed the fluoride conversion film was affected by the distribution of the chemical component of cast AZ31 alloy and the film on the second phases has more pores and micro-crack, but the bottoms of the pores were also covered by the conversion film and the substrate was not exposed through the pores. The fluoride conversion coatings significantly improved the corrosion resistance of cast AZ31 alloy. The film on the second phase with more pores is the first to dissolve. The most improved corrosion protection was achieved by 15 days treatment with the thickest film in terms of hydrogen evolution rate and damage morphology.

A model of the problem of variable load line contact EHL with single asperities is established. The influences of the single asperities and variable load on the pressure and film thickness are investigated. Numerical results reveal that the existence of single asperities can lead to pressure change drastically and film thickness become thin in the vicinity of asperities. The effects of the variable load on the pressure and film thickness are discussed. The comparison of the variable load and steady load is given.

The coal gangue are produced in a coal mine heap of Pan xian, Gui zhou, by using microwave assisted acid leaching methods and under certain reaction conditions, the products of different stages of acid leaching were characterized through different characterization methods like X-ray diffraction, scanning electron microscope and energy dispersive spectroscopy. The related process mechanism of Microwave assisted technique acid leaching gangue was preliminarily studied by the characterization results from analyzing the products of different stages of acid leaching.

To reduce the computational resources, experimental design and response surface method (RSM) were employed to investigate the aerodynamic drag coefficient (CD) and lift coefficient (CL) of airfoils by using CFD methods. The selection of sample points, development and validation of response surface model and the effects of different sample points on approximation model were discussed. The results indicates that the number and distribution of sample points have a significant impact on model accuracy and optimize results. Also this method can greatly reduce calculation amount.

The core device of our system is a handheld EEG monitoring analyzer, which is based on a new DSP (Digital Signal Processor) control system. The DSP is based on a Think-Gear module and collects the EEG signals reliably. The system only uses a dry electrode, which ensures that the user can have a happy experience in daily life. Our main purpose is that we can provide a hardware prototype with the application of BCI (Brain-Computer Interface).The system can monitor the sleep process accurately and distinguish the eyes open or closed state, sleep state and the degree of relaxation.

This paper applies AHP method and fuzzy evaluation method to establish evaluation system of CBM well type in Junggar Basin. Conclusions are drawn as follows: weight of each factor which determines well type optimization is very different, coal seam depth is 0.402, coal seam thickness is 0.295, coal permeability is 0.163, coal seam dip is 0.14. Sikeshu area and center of the basin is not suitable for CBM ground drilling. Changji to Fukang area and Muleihasakexian to Wucaiwan area and East Wuerhe area are favorable for vertical well drilling. Jimusaer area is favorable for horizontal well drilling. Other areas in Junggar Basin need vertical and horizontal well joint drilling.

Organic petrology method is applied to analysis hydrocarbon potential of early Cretaceous source rocks in Hebei Weichang, Chifeng basin. Conclusions are drawn as follows: Organic Maceral is mainly pieces of vitrinite, liptinite consists algae and small spores; organic matter abundance is better; organic type isI-II1, in an immature stage which currently does not have potential for bearing hydrocarbon.

Junggar Basin is located in north Xinjiang and it has a huge amount of coalbed methane resources with less exploration and mining. The most vital characteristic in junggar basin is coal dip angel and gas content varies a lot in different areas. This paper reveals the relationship between gas content and coal seam dip angel, bigger the coal seam dip angel lower the gas content. The target area of CBM exploration and mining in junggar basin is HEGSH-STH area, HEGSHX area, BSMY-JJM area,LJM area, KLMY area, HSTLG area and XZJQ area. Gas content is mainly influenced by tectonic movement in junggar basin, it is low in complex structure area and high in simple structure area. Inclination of the coal seam stands for the complexity of the structure in junggar basin, the structure is complex when the coal seam is steep, it is simple when the coal seam is flat. The result can be used as a new method for coalbed methane exploration and development in inclined coal seam areas, small coal dip area should be chosen as the high gas content target.

Based on the coal reservoirs geological feature and coalbed methane (CBM) wells production data, and taken FS-2 well in the southern Junggar Basin as examples, history matching and productivity prediction of FS-2 well were conducted by using COMET3 numerical modeling software and the influence factors sensitivity of gas well productivity in the study area were analyzed. The results suggest: FS-2 well total gas production in the eight years was 2915007 m3, and the average daily gas production reached 1209.5m3/d, the CBM well belongs to medium production well. Permeability and gas content has the most effect on the single wells production in the study area, so the influence of the fracture half-length and coal seam thickness is weakened.

Using data analysis and comparative analysis, the distribution of Coalbed methane (CBM) gas content in southern Junggar were analyzed on the basis of the southern Junggar Basin coalfield geological data, and the main controlling factors of CBM accumulation were studied. The results show that, Gas content ranges from 2cm3/g to 15cm3/g, which overall is highest in central and eastern and becomes progressively smaller in trend of westward. The study area has many characteristics, such as Multi-seam, large coal seam thickness, mainly Fine-grained clastic rock, which is conducive to the enrichment of the CBM. Study area belongs to confined aquifer of low water-richness and receives the supply of atmospheric precipitation and river. In the coal seams within a certain depth formed Runoff water and the CBM diffusion pattern of desorption - diffusion - transport - water soluble gas runoff, which are not conducive to the enrichment of the CBM.

In order to improve the corrosion resistance of Mg alloys as degradable implant material, fluorine conversion coatings were synthesized on AZ31 magnesium alloy by immersion in hydrofluoric acid (HF) for different time. Potentiodynamic electrochemical technique and hydrogen evolution testing were employed to investigate the corrosion behavior of the coated alloys in Hanks solution. It is indicated that the fluoride conversion coating, which is compact and composed of MgF2, can significantly decrease the degradation rate of Mg alloy AZ31 in Hanks solution. The most improved corrosion protection was achieved by immersion for 10 days. The corrosion current density was 40 times lower than that of the substrate and the hydrogen evolution rate of the coated sample was only one-fiftieth of the substrate.

In this paper, the finite element method is utilized to research the coupling effects between the strong electromagnetic pulse and the computer box with holes. Focus on the influence law of the box size on shielding effectiveness of computer box against strong electromagnetic pulses. The relationship between the simulation resonance frequency and the theoretical results is obtained; the influence of the holes shape and size on shielding effect is also obtained. It is concluded that the computer boxs shielding effect is poor under the resonance frequency, and there is no linear relationship between shielding effect and holes size when the frequency is determinated. The shielding effect doesnt become worse with the holes size increasing.

We propose and demonstrate an optical fiber acoustic sensor based on air backing mandrel type fiber optic hydrophone. This novel approach to sensing sounds in the air has not been utilized before and has the advantage that the sensor doesn’t need electric power supply when it is working. To prove the feasibility of such an optical fiber acoustic sensor, we make a model and set up experiment to get the acoustic waves response curve in frequency. Because of its simple mechanical structure, the sensor is robust and shows a good application prospect.

A new implementation of frequency shifting for the delayed self-heterodyne interferometer (DSHI) is proposed in this paper. In order to avoid the costly and complicated acoustic-optic modulator to shift frequency in the DSHI, we propose that a phase modulator can be used instead. The alternative strategy simplifies the complexity of the DSHI setup, as well as reduces the modulation-induced noise by modulating the two arms of DSHI at the same time. Theoretical and experimental analysis show that such a strategy successfully fulfills the frequency shifting function for the DSHI and accurate measurement of a laser’s linewidth and lineshape is realized correspondingly.

Aperture coupling is a main coupling mode through which strong electromagnetic pulse can disturb and even damage electronic equipments. The amount, offset and mixed shape of aperture arrays can affect the coupling effect, which is analyzed using finite-difference time-domain (FDTD) method. The field strength coupled increases with the decrease of the slot amount when the total area of aperture is unchanged. The shielding effectiveness is the smallest when the electromagnetic pulse reaches the resonant frequency, which is only affected by the actual structure size of the shielding cavity. Comparing to two direction offset, the single achieved much larger field strength, which is symmetrical about offset center. The coupled field strength is the smallest when the shape of aperture arrays contains round and rectangular.

To study damage effectiveness of strong electro-magnetic pulse to components of equipments, the power density in area of MOS circuit, diodes and transistor of a computer is simulated, using the method of the finite-difference time-domain (FDTD). Coupling laws in different areas are achieved, and then judging the damage efficiency of components. Electromagnetic pulse reflects constantly in computer box, causing power density appears oscillations. Energy gradually declines to zero, for it radiates outward from slots. Field concentration around PCB board results in dissociation of field strength, and slows down the attenuation of energy. Finally, formula of power density at random field strength and rise time is also obtained.

Taking a company’s automotive panel drawing die as an example, this paper numerically simulates the process of drawing forming based on finite element analysis (FEA) software ANSYS, the design rationality of die structure is analyzed combining distribution characteristics of stress and strain, the paper also proposes feasible improvment measures according simulation analysis to optimize the structure of drawing die. The study result shows that analysis results based on ANSYS can forecast defect and failure regions in the forming process of automotive panel drawing die, optimize the design of drawing die, prolong the die life effectively, and reduce production cost.

Successful application of magnesium alloys as degradable load-bearing implants is determined by their biological performance especially degradation and corrosion behavior in the human body. Three magnesium alloys, namely WE43, ZK60, and AZ91 are investigated in this work. The invitrodegradation behavior, cytotoxicity, and genotoxicity are evaluated by corrosion tests, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and micronuclei tests, respectively. Immersion tests indicate that the ZK60 alloy has the best corrosion resistance and lowest corrosion rate in Hank’s solution, followed by AZ91 alloy and WE43 alloy in that order. The MTT results obtained from the three magnesium alloys after 7 days of immersion indicate good cellular viability. However, excessively high aluminum and magnesium concentrations have a negative influence on the genetic stability.

In order to improve the corrosion resistance of Mg alloys in applications as degradable implant material. Fluoride conversion coating was synthesized on Mg alloy AZ31 by immersion in hydrofluoric acid (HF) with various concentrations. The effect of hydrofluoric acid (HF) treatment on the corrosion behavior of the Mg alloy AZ31 was investigated by potentiodynamic electrochemical technique and immersion tests. The XRD analysis indicated the fluoride conversion coating was amorphous, with smooth and compact surface. Electrochemical and immersion tests proved that the fluoride conversion coatings significantly improved the corrosion resistance of AZ31. The most improved corrosion protection was achieved using the concentrations of 40 % and 72 h of treatment time, resulting in corrosion rates 20 times lower than those of untreated samples, showing that fluoride coating by conversion treatment is a simple and promising way of enhancing the corrosion resistance of Mg in Hanks' solution.