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Suppression of gold nanoparticle agglomeration and its separation via nylon membranes

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Chinese Journal of Chemical Engineering 2017年第7期25卷 931-937页

作者： Ayyavoo Jayalakshmi In-chul kim Young-Nam Kwon School of Urban and Environmental Engineering Ulsan National Institute of Sdence and TechnologyUlsan 689-798Korea KIST-UNIST UIsan Center for Convergent Materials UNIST(Ulsan National Institute of Science and Technology)Korea Environment and Resources Research Center Korea Research Institute Chemical TechnologyDaejeon 305-606Korea

Use of ultraporous nylon membrane is one of the most widely employed techniques for removal of hard and soft nanoparticles in the semiconductor industry, and the accurate determination of membrane pore size is necessary in order to avoid manufacturing defects caused by contamination. The gold nanoparticle has several benefits for the evaluation of polymeric membranes; however, the nanoparticles agglomerate easily on the nylon membrane and make it difficult to evaluate the membrane precisely. The properties of 2-amino-2-hydroxymethyl-1,3-propanediol(ADP) ligand in gold nanoparticle solution were systematically investigated, and ADP was utilized for improved evaluation of the nylon membranes. Nylon membrane used in this study was prepared by phase inversion techniques. Ultrathin dense layer on top of the membrane surface and Darcy structures in the microporous membrane support were observed. The gold particle rejection was carried out at various p H values from 4 to14 and higher rejection was observed at p H 4 and 8. The suppression of gold colloid agglomeration using ADP and monodispersity of gold colloids was also analyzed by confocal laser scanning microscopy(CLSM), transmission electron microscopy(TEM), and scanning electron microscopy(SEM). van der Waals interaction energy of the particles was reduced in the addition of ADP. The presence of ADP ligand in the gold solutions prevented the agglomeration of gold nanoparticles and reduced the adsorption of the particles on the nylon membrane surface,leading to precise evaluation of membrane pore sizes.

关键词： Particle size Electron microscopy Gold colloid flock Semiconductor

Ultrafast synthesis of gold nanoparticles on cellulose nanocrystals via microwave irradiation and their dyes-degradation catalytic activity

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Journal of Materials Science & Technology 2020年第6期41卷 168-177页

作者： Madhusudhan Alle Seung-Hwan Lee Jin-chul kim Institute of Forest Science Kangwon National UniversityChuncheon 24341Republic of Korea Department of Forest Biomaterials Engineering Kangwon National UniversityChuncheon 24341Republic of Korea Department of Medical Biomaterials Engineering College of Biomedical Science and Institute of Bioscience and BiotechnologyKangwon National University192-1Hyoja 2 dongChuncheonKangwon-do 200-701Republic of Korea

This study represents a well-dispersed gold nanoparticles(AuNPs)synthesis process via cellulose nanocrystals(CNC)which acts as both reducing and supporting *** synthesis process was ultrafast and completed in a few seconds using microwave *** entire synthesis process was cost-effective,sustainable and *** synthesized(AuNPs/CNC)nanocomposite was investigated by transmission electron microscopy,selected area electron diffraction,Fourier transform infrared spectroscopy,energy dispersive X-ray analysis,X-ray diffraction,and UV–vis *** obtained AuNPs were well accumulated on the CNC surface and had a uniform spherical shape with an average diameter of 8±5.3 *** diameter of AuNPs could be altered by tuning the concentration of CNC *** synthesized AuNPs/CNC nanocomposite film exhibited excellent degradation properties against various organic dyes,namely,Allura red,Congo red,Rhodamine B and *** ultrafast degradation reactions followed pseudo first order *** the catalytic degradation reaction,AuNPs/CNC was transmitting electrons from a donor(NaBH4)to an acceptor(a dye).

关键词： Cellulose nanocrystals Gold nanoparticles Microwave synthesis Catalytic degradation of dyes

Impact of surgical volume on nationwide hospital mortality after pancreaticoduodenectomy

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World Journal of Gastroenterology 2012年第31期18卷 4175-4181页

作者： chul-Gyu kim Sungho Jo Jae Sun kim Department of Nursing Cheongju UniversityCheongjuChungbuk 360-764South Korea Department of Surgery Dankook University College of MedicineCheoanChungnam 330-714South Korea Health Insurance Review and Assessment Service Seoul 137-706South Korea

AIM:To evaluate the impact of surgical volume on nationwide hospital mortality after pancreaticoduodenectomy(PD) for periampullary tumors in South ***:Periampullary cancer patients who underwent PD between 2005 and 2008 were analyzed from the database of the Health Insurance Review and Assessment Service of South Korea.A total of 126 hospitals were divided into 5 categories,each similar in terms of surgical volume for each *** used hospital mortality as a quality indicator,which was defined as death during the hospital stay for PD,and calculated adjusted mortality through multivariate logistic models using several confounder ***:A total of eligible 4975 patients were enrolled in this *** annual surgical volume of hospitals was markedly varied,ranging from 215 PDs in the very-high-volume hospital to < 10 PDs in the verylow-volume *** route,type of medical security,and type of operation were significantly different by surgical *** overall hospital mortality was 2.1% and the observed hospital mortality by surgical volume showed statistical *** volume,age,and type of operation were independent risk factors for hospital death,and adjusted hospital mortality showed a similar difference between hospitals with observed *** result of the HosmerLemeshow test was 5.76(P = 0.674),indicating an acceptable appropriateness of our regression ***:The higher-volume hospitals showed lower hospital mortality than the lower-volume hospitals after PD in South Korea,which were clarified through the nationwide database.

关键词： Hospital mortality Pancreaticoduodenecto-my South Korea Databases Factual Logistic models Risk factors

Integrated Design of D.D.I., Filament Winding and Curing Processes for Manufacturing the High Pressure Vessel(Type Ⅱ)

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Chinese Journal of Mechanical Engineering 2019年第5期32卷 170-181页

作者： Hyoseo Kwak Gunyoung Park Hansaem Seong chul kim Research Institute of Mechanical Technology Pusan National UniversityPusan 609-735Korea Department of Mechanical Convergence Technology Pusan National UniversityPusan 609-735Korea School of Mechanical Engineering Pusan National UniversityPusan 609-735Korea

As energy crisis and environment pollution all around the world threaten the widespread use of fossil fuels,compressed natural gas(CNG)vehicles are explored as an alternative to the conventional gasoline powered *** of the limited space available for the car,the composite pressure vessel(TypeⅡ)has been applied to the CNG vehicles to reach large capacity and weight lightening *** pressure vessel(TypeⅡ)is composed of a composite layer and a metal *** metal liner is formed by the deep drawing and ironing(D.D.I.)process,which is a complex process of deep drawing and *** cylinder part is reinforced by composite layer wrapped through the filament winding process and is bonded to the liner by the curing *** this study,an integrated design method was presented by establishing the techniques for FE analysis of entire processes(D.D.I.,filament winding and curing processes)to manufacture the CNG composite pressure vessel(TypeⅡ).Dimensions of the dies and the punches of the 1 st(cup drawing),2 nd(redrawing-ironing 1-ironing 2)and 3 rd(redrawing-ironing)stages were calculated theoretically,and shape of tractrix die to be satisfied with the minimum forming load was suggested for life improvement and manufacturing costs in the *** of the composite material was determined in the filament winding process,finally,conditions of the curing process(number of heating stage,curing temperature,heating rate and time)were proposed to reinforce adhesive strength between the composite layers.

关键词： Pressure vessel(Type Ⅱ) D.D.I. Filament winding Curing process FEM

Recent advancement in diagnosis of vasculogenic impotence

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Asian Journal of Andrology 1999年第1期1卷 37-43页

作者： Sae chul kim Department of Urology College of Medicine Chung-Ang University Seoul Korea

Several dynamic tests with vasoactive drags are available for evaluating penile vascular inflows and outflows,ranging from simple pharmacologic test to more invasive radiologic sets. However, there is still no perfect single testto reflect the penile vascular flow. All possible efforts should be exerted to get the greatest erectile effect to avoid anunderestimation of blood flow to the corpora due to incomplete relaxation of the trabecular smooth *** of the type and frequency of anatomical variations and potential collateral routes is important in interpretingpenile arterograms and in evaluating the hemodynamic significance of suspected arterial disease. Choice of the vasculartests should always depend on the purpose of testing.

关键词： vasculogenic impotence diagnosis cavernosography cavernosometry penile erection blood flow velocity hemodynamics angiography

Optimal design considering structural efficiency of compressed natural gas fuel storage vessels for automobiles

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 199-204页

作者： Myung-Chang KANG Hyung Woo LEE chul kim National Core Research Center for Hybrid Materials Solution Pusan National University Research Institute of Mechanical Technology Pusan National University

The shape and thickness of the dome were investigated with the aim of optimizing the type II CNG storage vessels by using a finite element analysis technique. The thickness of the liners and reinforcing materials was optimized based on the requirement of the cylinder and dome parts. In addition, the shape of the dome, which is most suitable for type lI CNG storage vessels, was proposed by a process of review and analysis of various existing shapes, and the minimum thickness was established in this sequence： metal liners, composite materials and dome parts. Therefore, the new proposed shape products give a mass reduction of 4.8 kg（5.1%）

关键词： CNG fuel storage vessel mechanical property dome part bursting structural analysis

Electrochemical and electronic properties of nitrogen doped fullerene and its derivatives for lithium-ion battery applications

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Journal of Energy Chemistry 2018年第2期27卷 528-534页

作者： Parveen Sood Ki chul kim Seung Soon Jang School of Materials Science and Engineering Georgia Institute of Technology Atlanta CA 30332-0245. USA Department of Chemical Engineering Konkuk University Seoul 05029 Republic of Korea Institute for Electronics and Nonotechnology Georgia Institute of Technology Atlanta GA 30332-0245 USA Parker H. Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology Atlanta GA 30332-0245 USA

We have studied the redox potentials and electronic properties of C60 and C59N using density functional theory method. It is found that doping C60 with one nitrogen atom results in a slight increase in redox potential. Next, we have also studied C59N functionalized with various redox-active oxygen containing functional groups and strongly electron withdrawing functional groups. It is found that the intrinsic electronic structure of the molecule is the major determinant of the redox potential. Our DFT calculations show that the electron affinity to redox potential of functionalized C59N is correlated with the LUMO of the systems very well. This is the first systematic study on the redox properties and electronic structures of N-doped C60 systems.

关键词： DFT Redox potential C60 Doping Li-ion battery

Modeling the effects of constructed wetland on nonpoint source pollution control and reservoir water quality improvement

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Journal of Environmental Sciences 2010年第6期22卷 834-839页

作者： Jonghwa Ham Chun G.Yoon Hyung-Joong kim Hyung-chul kim Rural Research Institute of KRC Environmental Science Department Konkuk University

This article describes the integrated modeling approach for planning the size and the operation of constructed wetlands for maximizing retention of nonpoint source pollutant loads and reservoir water-quality improvement at a catchment scale. The experimental field-scale wetland systems （four sets, 0.88 ha each） have been in operation since 2002, where water depth was maintained at 30-50 cm and hydraulic loading rate was at 6.3-18.8 cm/day. The wetland system was found to be adequate for treating polluted stream water with stable removal efficiency even during the winter. The integrated modeling system （modified-BASINS） was applied to the Seokmoon estuarine reservoir watershed and calibrated with monitoring data from constructed wetland, stream, and reservoir. The calibrated integrated modeling system estimated that constructing wetlands on 0.5% （about 114 ha） of the watershed area at the mouth of reservoir could reduce 11.61% and 13.49% of total external nitrogen and phosphorus loads, respectively. It also might improve the nitrogen and phosphorus concentration of the reservoir by 9.69% and 16.48%, respectively. The study suggested that about 0.1%-1.0% of the watershed area should be allocated for constructed wetland to meet specified water-quality standards for the estuarine reservoir at the polder area where land use planning is relatively less complicated.

关键词： constructed wetland estuarine reservoir integrated modeling system nonpoint source pollution control polder area water quality improvement

Development of fault section identification technique for low voltage DC distribution systems by using capacitive discharge current

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Journal of Modern Power Systems and Clean Energy 2018年第3期6卷 509-520页

作者： chul-Ho NOH chul-Hwan kim Gi-Hyeon GWON Yun-Sik OH College of Information and Communication Engineering Sungkyunkwan University

The increasing importance of energy efficiency has led to several studies related to the construction of a reliable low voltage DC(LVDC) distribution ***, studies on a protection scheme that considers the fault characteristics of an LVDC distribution system are essential to improve system reliability. When compared to a conventional distribution system, the most distinct feature of an LVDC distribution system is the existence of a capacitive discharge current from converters under a fault condition that results in the prompt operation of protection devices. Therefore, this study involves proposing a precise and rapid technique to identify the fault section in an LVDC distribution system. The technique involves two stages, namely: an analysis stage to analyze the capacitive discharge current and a decision stage to identify the fault section based on the fault type. A detailed discussion of each step is presented and its feasibility is verified based on the results of simulations with an ElectroMagnetic Transients Program and MATLAB~?.

关键词： Capacitive discharge current Fault section identification Fault type identification Low voltage DC distribution system