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81.
Kuo-Hsiung Tseng Juei-Long Chiu Heng-Lin Lee Yi-Syuan Kao Der-Chi Tien 《Materials and Manufacturing Processes》2016,31(2):186-193
This study developed a system monitoring the electric discharge machine's (EDM) discharge energy and success rate to replace conventional oscilloscope observation. By using logic circuit, the signals are transmitted to the PC monitoring platform in order to display the discharge success times, discharge success rate, and electrode's consumption energy. The advantage of the proposed system is the capability to observe real-time discharges and record the experimental conditions, as well as optimize the discharge parameter settings. The experimental results suggest that, in the preparation of nanosilver colloid, the cost-performance of Ton–Toff at 10–100 µs is the optimal setting. The monitoring system also can take advantage of the discharge success rate to control the energy consumption of the electrode to obtain the standardization of products. The results suggest that, while discharge success rate, electrode's weight loss and wavelength of the absorption peak are considerably accurate, but concentration accuracy is relatively poor. The discharge success rate monitoring system is an innovative method that can help to realize electric discharge processing, optimize product quality, and it may be a powerful processing tool in the future. 相似文献
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In recent decades India has achieved one of the fastest economic growth rates in the world, yet its progress against both
child and adult undernutrition has been sluggish at best. While this Indian variant of the so-called Asian enigma presents
many puzzles, one of the puzzles pertains to agriculture’s role. Many researchers and policymakers have high expectations
of agriculture’s potential to reduce undernutrition, despite a lack of substantive evidence. In this paper we assess this
tenuous evidence base by exploring two key channels by which agricultural production conditions can influence nutritional
outomes: a food consumption pathway and a maternal employment–time use pathway. We conclude with an appraisal of some possible
entry points for pro-nutrition agricultural policies. 相似文献
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Abstract This work considers the application of Wilson and NRTL equations in the multicomponent VLE prediction. We emphasize the critical comparison of partially miscible solution treatment by these two equations. Results revealed NRTL equation performed slightly better than the Wilson equation in data credibility so far as the systems examined are concerned. Estimation of optimum NRTL parameters requires further exploration. Optimization methods of pattern search, gradient search and golden section were employed in this study. All of the computations were performed on an IBM 1130 digital computer. 相似文献
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A theoretical framework, accounting for high-order surface stress, is implemented in a continuum mechanics model based on the Euler-Bernoulli theory of beams and columns to simulate the buckling and resonance behavior of nanowires (NWs). Closed-form expressions for the critical buckling load of uniaxial compression of NWs are derived for different types of end conditions. Size-dependent overall Young’s modulus is characterized versus the diameter of the NWs and is compared with the experimental data. The resonance frequency of NWs is also studied and compared with the simulation results based on nonlinear, finite deformation kinematics. We demonstrate that the present prediction considering both surface moment and surface stress agrees well with the experimental data, while the pure surface stress model may not be able to capture the general trend when the NW’s diameter is less than a certain size. We conclude that the present continuum mechanics approach, considering both high-order surface effects, could be served as one of the feasible tools to analyze the mechanical behavior of nanostructures. 相似文献
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Preparation and characterization of methoxy‐poly(ethylene glycol) side chain grafted onto chitosan as a wound dressing film 下载免费PDF全文
Cheng‐Han Yang Szu‐Hsien Chen Yun‐Wen Pan Ching‐Nan Chuang Wen‐Chi Chao Tai‐Horng Young Wen‐Yen Chiu Chih‐Kuang Wang Kuo‐Huang Hsieh 《应用聚合物科学杂志》2015,132(31)
Chitosan has received extensive attention as a biomedical material; however, the poor solubility of chitosan is the major limiting factor in its utilization. In this study, chitosan‐based biomaterials with improved aqueous solubility were synthesized. Two molecular weights (750 Da and 2000 Da) of methoxypoly(ethylene glycol) (mPEG) were grafted onto chitosan (mPEG‐g‐chitosan) to form a ~100‐μm‐thick plastic film as a wound dressing. The chemical structures of the mPEG‐g‐chitosan copolymers were confirmed using Fourier transform infrared spectroscopy (FTIR), and the thermal properties were characterized using thermogravimetry analysis (TGA). Their microstructures were observed using scanning electron microscopy (SEM). The other properties were analyzed via the swelling ratio, tensile strength, elongation, and water vapor transmission rate (WVTR). Biocompatibility evaluations through biodegradability, cytotoxicity, and antimicrobial effect studies were also performed. The obtained mPEG‐g‐chitosan copolymers were soluble in slightly acidic aqueous solutions (pH~6.5) at a concentration of 10 wt %. The optimal mPEG‐g‐chitosan hydrogels had swelling ratios greater than 100% and WVTRs greater than 2000 g/m2/day. Their performance against Staphylococcus aureus will be subjected to further improvements with respect to medical applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42340. 相似文献
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