Key Engineering Materials Vols. 480-481

Abstract: In order to improve the yield of antimicrobial substances extracted from actinomycetes F10 strains fermentation, antimicrobial activity and cell dry weight were taken as the main indicators, we studied the effects on F10 strain’s biological activity of the different fermentation media, different carbon, nitrogen and other nutrients factor, and the initial pH and other non-nutritional factors. The results showed that the optimum fermentation medium is: yeast extract 0.5%, glucose 1%, KH2PO4 0.1%, NaCl 0.1%, CaCO30.3%, pH natural. Strain F10 optimal fermentation conditions were: initial pH 7.0, fermentation time 168h.

Abstract: Excessive noise was joined with the acquiring wood defect images process in wood non-destructive testing. The image quality was affected. Wavelet packet transform could decompose high frequency and low frequency of signal at the same time. There were characteristics of open and closed in Gray-scale Morphology. Denoising method of wood defect images based on wavelet packet combined with gray-scale morphological filtering was proposed. Compared with the traditional denoising method, the method received better Peak Signal to Noise Ratio (PSNR) and visual effect. Experimental results verified the feasibility and effectiveness of this method.

Abstract: The Y/MCM-41 composite molecular sieves were synthesized in the method of hydrothermal crystallization with cetyltrimethylammonium bromide (CTMABr) as the template agent. The as-prepared composite molecular sieves were characterized by the means of X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), the thermogravimetric and differential thermal analysis (TG-DTA) and the nitrogen adsorption test. The experimental results were shown as follows: the Y/MCM-41 composite molecular sieves kept properties of Y-zeolites and MCM-41 molecular sieves. In the XRD and FT-IR spectra, it can be found both characteristic peaks of Y-zeolites and MCM-41 molecular sieves. The pore size distribution plot indicated that the Y/MCM-41composite molecular sieves had micro-mesoporous structure, and the average pore size were about 1.5 nm and 15 nm. The decomposition temperature of the template agent was at 320 °C, and the calcined temperature of Y-zeolites was at about 560 °C. There showed an endothermic process constantly in the DTA curve, and there was little mass loss in the TG curve, indicating the obtained Y/MCM-41 composite molecular sieves had higher thermal stability.

Abstract: The ZSM-5/MCM-41 composite molecular sieves were synthesized in the method of hydrothermal crystallization in the presence of cetyltrimethylammonium bromide (CTMABr) as template agent. The prepared composite molecular sieves were characterized by the means of X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and the thermogravimetric and differential thermal analysis (TG-DTA). The experimental results showed that as-prepared ZSM-5/MCM-41 composite molecular sieves kept both crystal structure and compositions of ZSM-5 zeolites and MCM-41 molecular sieves. The decomposition temperature of the template agent was 293°C, and the decomposition temperature of the molecular sieve framework was higher than 800 °C. We supposed that the obtained ZSM-5/MCM-41 composite molecular sieves had high thermal stability, framework rigidity and structural stability, and could combine the properties of ZSM-5 zeolites and MCM-41 molecular sieves successfully.

Abstract: Six reinforced concrete beams were constructed and tested to investigate the effectiveness of strengthening with prestressed carbon fiber reinforced polymer (CFRP) plates. One of the beams served as a control specimen, another was strengthened with nonprestressed CFRP plates, and the remaining four were strengthened with prestressed CFRP plates. A set of self-developed anchorage devices for CFRP plates were introduced in this program. Monotone static loading experiments was carried out, and comparisons are made between the control beam, the nonprestressed beam and the prestressed beams. The serviceability and the ultimate performance of the concrete beams were improved by strengthened with prestressed CFRP plates.

Abstract: The tribological behavior of two types of ceramic frames reinforced 7075 Al alloy against Cr12 steel have been studied with oscillating dry friction and wear tester, one is for 3-D continuous foam ceramic and the other is for 2-D continuous comb ceramic. The testing temperatures are 70°C and 270°C, for 30min under the load from 40N to 100N. The experimental results show that it is characteristic of abrasive wear and oxidation wear mechanisms for both continuous ceramic/Al-7075 composites. The friction resistance of comb ceramic reinforced composite is better than foam ceramic reinforced composite, since the former is with continuous ceramic frame on the worn surface while the latter is with discontinuous hard convex on the plane. In addition, the composite reinforced by 2-D comb ceramic exhibits better high-temperature friction resistance than the one reinforced by 3-D foam ceramic, for the metal matrix filling in comb ceramic is not continuous in 3-D space, which leads to the deterioration of thermal metal softening at high temperature.

Abstract: Random mechanical properties are experimentally studied on China grade B cast steel wheel. Significant dimples and fabric-like tearing signs were observed firstly and then, lotus flower-like cleavage fracture faces were appeared to indicate the material subjected to a plastic dissipation process under monotonic load. Randomness appears in the deformation process companied with a similarity in total and significant differences in local. Appropriate statistical description is explored with a comprehensive statistical comparison method. Lognormal distribution is excavated out by comparison from seven possible statistical models. Random characters and quantitative measurements have been given for the mechanical properties of China grade B cast steel wheel.

Abstract: As a type of the novel semiconductor materials, tungsten oxide (WO3) is applied extensively in recent years for its electrochromic property. It has been widely used in many different applications, such as electrochromic windows, optical devices, fuel cells, gas sensors, and photocatalyst materials, etc. Based on the study on the preparation of platinum-doped WO3 films, we studied the optical and hydrogen sensitive properties of the films. In this work, firstly, the preparation method of the platinum-doped WO3 films was discussed. Secondly, we studied the transmissivity of the films. Thirdly, the restoration and the repeatability of the films was discussed. This work can provide theory support for the design of optic-fiber sensor for hydrogen concentration measurement.

Abstract: To resolve the question: accurately scanned the port of remote network host through firewall, researched deeply on the existing scan methods, found their weakness, provided a new method about port detection through firewall. Described the design thinking and scan process, design the first part of ETHERNET, send out and receive of the data packet was turned from the IP layer to data link layer. delivered the data packet directly to network hosts. At last, developed the network security assessment system based on this way. Test results show that this method can penetrate firewall and accurately scan the port of remote network host.

Abstract: At present, the sewage of China’s inland waterway vessels was mostly discharged directly without any treatment, therefore, the inland water pollution is increasingly serious. How to deal with the sewage of inland river steamer in an effective way has become one of the most urgent problems to be solved regarding the inland water environment protection. In this paper, with comparative studies, using the membrane bioreactor (MBR) technology, we have designed and developed the ship sewage treatment device, which is small in size, high efficiency, no secondary pollution and suit for 8 people to use. This provides an effective solution t sewage treatment for our country’s inland waterway vessels.