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111.
Preparation of dual‐layer acetylated methyl cellulose hollow fiber membranes via co‐extrusion using thermally induced phase separation and non‐solvent induced phase separation methods 下载免费PDF全文
Hanna Jang Du‐Hyun Song Hye‐Jin Lee Seong‐Han Lim In‐Chul Kim Young‐Nam Kwon 《应用聚合物科学杂志》2015,132(43)
Dual‐layer acetylated methyl cellulose (AMC) hollow fiber membranes were prepared by coupling the thermally induced phase separation (TIPS) and non‐solvent induced phase separation (NIPS) methods through a co‐extrusion process. The TIPS layer was optimized by investigating the effects of coagulant composition on morphology and tensile strength. The solvent in the aqueous coagulation bath caused both delayed liquid–liquid demixing and decreased polymer concentration at the membrane surface, leading to porous structure. The addition of an additive (triethylene glycol, (TEG)) to the NIPS solution resolved the adhesion instability problem of the TIPS and NIPS layers, which occurred due to the different phase separation rates. The dual‐layer AMC membrane showed good mechanical strength and performance. Comparison of the fouling resistance of the AMC membranes with dual‐layer polyvinylidene fluoride (PVDF) hollow fiber membranes fabricated with the same method revealed less fouling of the AMC than the PVDF hollow fiber membrane. This study demonstrated that a dual‐layer AMC membrane with good mechanical strength, performance, and fouling resistance can be successfully fabricated by a one‐step process of TIPS and NIPS. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42715. 相似文献
112.
Automated speed enforcement system (ASES) has been deployed as a safety countermeasure on Korean roadways to reduce speeding-related traffic crashes; information on ASES locations is mandated to be open to the public. However, because drivers are alerted about enforcement via on-board navigation systems and roadside signs, they can avoid enforcement by momentarily reducing their speeds near ASES locations. This enforcement avoidance behavior (EAB) can induce sudden changes in speed near the enforcement locations and thereby increase risk of crash occurrence. 相似文献
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114.
Ja Young Park Mi Ae Kim Seung Jae Lee Jongjin Jung Hye Mi Jang Pravin P. Upare Young Kyu Hwang Jong-San Chang Joung Kyu Park 《Journal of Materials Science》2015,50(1):334-343
This study describes the synthesis of carbon-encapsulated iron nanoparticles using an ultrasonic method and also investigates their catalytic activity. These nanoparticles have been prepared using ultrasonic irradiation followed by annealing at various temperatures. As the annealing temperature of as-prepared α-Fe2O3 nanoparticles increased, the sample transformed into γ-Fe2O3, Fe3O4, and Fe nanoparticles via the reduction process without requiring any additional reducing agents such as H2 gas, thus, creating a carbon shell surrounding the nanoparticles. By controlling the experimental conditions, Fe nanoparticles of various sizes can be formed with diameters in the range 100–800 nm; these nanoparticles are tightly encapsulated by 20-nm-thick carbon shells. Because of their high saturation magnetization 212 emu g?1, the carbon-encapsulated Fe nanoparticles can be used for magnetic resonance imaging with a dramatically enhanced efficiency compared to commercially available T 2 contrast agents. Moreover, the carbon-encapsulated Fe nanoparticles showed its superior catalytic activity and reusability for the hydrogenation of biomass-derived levulinic acid to GVL (99.6 %) in liquid phase. 相似文献
115.
Visualization Approaches for Evaluating Ridge Regression Estimators in Mixture and Mixture‐Process Experiments 下载免费PDF全文
Dae‐Heung Jang Christine M. Anderson‐Cook 《Quality and Reliability Engineering International》2015,31(8):1483-1494
When the component proportions in mixture experiments are restricted by lower and upper bounds, the input space of a designed experiment space can become an irregular region that can induce multicollinearity problems when estimating the component proportion parameters. Thus, ridge regression provides a beneficial means of stabilizing the coefficient estimates in the fitted model. Previous research has focused on using prediction variance as a metric for determining an appropriate value of the ridge constant, k. We use visualization techniques to illustrate and evaluate ridge regression estimators and the robustness of estimation with respect to the variance and the bias. The addition of bias allows better balancing between the stability of the estimators and minimally changing the estimates. We illustrate the graphical methods with mixture and mixture‐process examples from the literature. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
116.
Ronald F. Gibson Hong-Kyu Jang Sushir Simkhada Qin Yu Hyung-Ick Kim Jonghwan Suhr 《Particulate Science and Technology》2015,33(2):213-218
This article describes the use of a combination of experimental nanoindentation and finite element numerical simulations to indirectly determine the elastic modulus of individual porous, micron-sized silica (SiO2) particles. Two independent nanoindentation experiments on individual silica particles were employed, one with a Berkovich pyramidal nanoindenter tip, the other with a flat punch nanoindenter tip. In both cases, 3D finite element simulations were used to generate nanoindenter load–displacement curves for comparison with the corresponding experimental data, using the elastic modulus of the particle as a curve-fitting parameter. The resulting indirectly determined modulus values from the two independent experiments were found to be in good agreement, and were considerably lower than the published values for bulk or particulate solid silica. The results are also consistent with previously reported modulus values for nanoindentation of porous thin film SiO2. Based on a review of the literature, the authors believe that this is the first article to report on the use of nanoindentation and numerical simulations in a combined experimental/numerical approach to determine the elastic modulus of individual porous silica particles. 相似文献
117.
DNA Hydrogels: DhITACT: DNA Hydrogel Formation by Isothermal Amplification of Complementary Target in Fluidic Channels (Adv. Mater. 23/2015) 下载免费PDF全文
118.
Materials and Wireless Microfluidic Systems for Electronics Capable of Chemical Dissolution on Demand 下载免费PDF全文
Chi Hwan Lee Jae‐Woong Jeong Yuhao Liu Yihui Zhang Yan Shi Seung‐Kyun Kang Jeonghyun Kim Jae Soon Kim Na Yeon Lee Bong Hoon Kim Kyung‐In Jang Lan Yin Min Ku Kim Anthony Banks Ungyu Paik Yonggang Huang John A. Rogers 《Advanced functional materials》2015,25(9):1338-1343
Electronics that are capable of destroying themselves, on demand and in a harmless way, might provide the ultimate form of data security. This paper presents materials and device architectures for triggered destruction of conventional microelectronic systems by means of microfluidic chemical etching of the constituent materials, including silicon, silicon dioxide, and metals (e.g., aluminum). Demonstrations in an array of home‐built metal‐oxide‐semiconductor field‐effect transistors that exploit ultrathin sheets of monocrystalline silicon and in radio‐frequency identification devices illustrate the utility of the approaches. 相似文献
119.
Ahn Seoyeon Nam Chanhyuk Choi Sungjin An Daekwon Kim Ingi Seo Kyungsoo Sohn Changhyun 《Journal of Mechanical Science and Technology》2021,35(5):1923-1933
Journal of Mechanical Science and Technology - In this paper, to help reduce the squeal noise produced during the braking of urban railway vehicles, the shape of the disc brake pad was investigated... 相似文献
120.
We propose a geometric approach to animating thin surface features of smoothed particle hydrodynamics‐based water. Explicit interparticle connections are created among smoothed particle hydrodynamics particles to approximate the geometries of thin surfaces while addressing the issue of unresolved surface areas. The deformations measured on the connections actuate the animations of the surfaces by disconnecting the stretched and bent connections. The reconstruction of thin surfaces and the accuracy of the animation are improved by adding auxiliary particles over the connections via Poisson‐disk sampling. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献