In this paper, the mechanism of radio frequency (RF) causing fire and explosion directly and indirectly was recommended, studies of RF risks in flammable and explosive environments were summarized, some problems in RF risk researches recently were discussed, study prospects of RF risks in flammable and explosive environments were analyzed. The fact that the mechanisms and conditions of RF igniting combustible gases should be researched by more deeply theories and technological means, and that RF security standards should be laid down and a complete and precise RF security assessment system should be established in flammable and explosive environments was put forward.
In this study, Cu/TiB2 composite coating was in-situ prepared on 304 steel by laser cladding. This coating applies to hospitals, schools and some public places where cross infections happen more easily because of its good antimicrobial properties and abrasion resistance. Before laser cladding, pre-blend of Cu powder, Ti powder and B powder were undertaken by ball-milling in two different proportions (10% wt (Ti+B) and 20% wt (Ti+B)). And the atomic ratio of Ti and B was 1:2. After a series of experiments, the best parameters were achieved. They were laser power (950W), scanning speed (14mm/s) and spot diameter (3.8mm). Samples after laser cladding were characterized using optical microscopy, scanning electron microscopy and X-ray diffraction. The results showed that TiB2 was fabricated in-situ. The dispersion degree of Cu was higher in the coating of 20% wt (Ti+B). The hardness of the 10% wt (Ti+B) coating was HRC57±4. With the increase of percentage of wt (Ti+B), the hardness of 20% wt (Ti+B) coating was HRC74±5. Both of them performed better than pure copper. Relative to pure copper, the abrasion resistance of Cu/TiB2 composite coatings was more excellent. The results of antimicrobial experiments showed that, with the increase of percentage of wt (Ti+B), the antimicrobial properties were decreasing. But they still could to be considered favorable.
The processing of target image using image processing technology, can realize the non-contact online detecting circuit board, thus greatly improve the detection efficiency, reducing the defective rate. This paper provides the detection system based on the methods of pre-processing the standard circuit board image and the circuit board image to be detected, two value segmentation, morphological image processing, image registration and poor shadow detection processing, among them ,image registration is the key. In order to improve the processing speed to achieve real-time processing, image registration using rapid processing algorithm. Analysis of the experimental results, the method can detect the defects on the circuit board to be detected accurately, and can achieve the automatic real-time detection purposes.
Through the analyzing of the color, motion, parallax and the degree of clarity in scene-all the elements presented on the 2D video, People can produce 3D video smoothly. The paper introduces a kind of pick-up algorithm of depth map, the method of combining the abstraction of motion in depth based on the block matching and the abstraction of background in depth on the basis of background subtraction. The extracted map can be applied to the video conversion technology of "2D to 3D".
For the technical requirements of a domestic enterprise to develop a new generation of self-loading container truck products, this paper creatively puts forward a set of suitable reduction standards for special structure. Based on ANSYS and Visual Studio 2008 platform, the parametric modeling and automatic analysis of side loader container structure are achieved independently. Several operating conditions, such as stacking, self-loading and unloading etc. can be analyzed rapidly and automatically. The research achievement can be not only used for the conceptual design stage of forward design process, but also applied in the modification of the original structure, thus effectively shortening the product design cycle, reducing design cost, providing useful guidance for independent research of domestic enterprise.
Synchronization is very important for any digital transmission technology. It can almost be said the core of any control system, so the synchronization algorithm is precisely the premise to transmit data correctly. This point is especially important for OFDM system. Synchronous error is the biggest shortcoming of OFDM system, the performance of the receiver is closely related to if we can get the accurate synchronization signal.
Concrete structures are exposed to severe environment that may cause rapid decay, shortening their service life and raising maintenance and repair costs. Chloride ions will lead to the depassivation of reinforcing steel bars in concrete which is one of the most serious problems to the durability of concrete. Then, the prescriptive methodology is not a guarantee to obtain the desired service lives of 50 or 100 years. Surface treatment is commonly used to improve the resistance of concrete to chloride erosion. Using the silicone materials to an immersion treatment can effectively block the invasion of harmful substances,the resistance of concrete to chloride penetration with surface protection with silicone materials was evaluated. The results showed silicone can improve the resistance to chloride penetration than the non-protected concretes. As a kind of polymer materials, the aging behaviors of silane is a matter of urgent concern. Hence, the aging behavior of silane coated concrete is evaluated by the test of water absorption after 1000h xenon lamp aging, which exhibits excellent anti-aging performance of silane.
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