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Characterization of Ceramic Composite-Membranes Prepared by ORMOSIL Coating Sol

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Journal of Rare Earths 2004年第z2期22卷 136-140页

作者： goo-Dae kim Tae-bong kim School of New Materials Science and Engineering Yonsei UniversitySeoul 120-749Korea Division of MaterialsKorea Institute Science and TechnologySeoul 136-791Korea

Sol-gel methods offer many advantages over conventional slip-casting, including the ability to produce ceramic membranes. They are purer, more homogeneous, more reactive and contain a wider variety of compositions. We produced ormosil sol using sol-gel process under different molecular weight of polymer species [polyethylene glycol (PEG) ] in total system [Tetraethyl ortho silicate(TEOS)-polyethylene glycol (PEG)]. The properties of as-prepared ormosil sol such as,viscosity, gelation time were characterized. Also, the ceramic membrane was prepared by dip-coating with synthetic sol and its micro-structure was observed by scanning electron microscopy. The permeability and rejection efficiency of membrane for oil/water emulsion were evaluated as cross-flow apparatus. The ormosil sol coated Membrane is easily formed by steric effect of polymer and it improves flux efficiency because infiltration into porous support decreased. Its flux efficiency is elevated about 200(1/m2·h) compared with colloidal sol coated membrane at point of five minutes from starting test.

关键词： ORMOSIL sol crack Resistance ultra-filter micro-filter

Integrated guidance and control for damping augmented system via convex optimization

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Chinese Journal of Aeronautics 2022年第7期35卷 30-39页

作者： bong-Gyun PARK Tae-Hun kim The 1^(st)R&D Institute-4 Agency for Defense DevelopmentDaejeon 34186Republic of Korea

In this paper,an integrated guidance and control approach is presented to improve the performance of the missile *** approach includes damping augmented system with attitude rate feedback to decrease the oscillation during the homing phase for missiles with low *** addition,physical constraints,which can affect the performance of the missile interception,such as acceleration limit,seeker’s look angle,and look angle rate constraints are *** integrated guidance and control problem is formulated as a convex quadratic optimization problem with equality and inequality constraints,and the solution is obtained by a primal–dual interior point *** performance of the proposed method is verified through several numerical examples.

关键词： Convex optimization Damping augmented system Integrated guidance and control Physical constraint Primal-dual interior point method

Comparative long-term outcomes for pancreatic volume change, nutritional status, and incidence of new-onset diabetes between pancreatogastrostomy and pancreatojejunostomy after pancreaticoduodenectomy

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Hepatobiliary Surgery and Nutrition 2020年第3期9卷 284-295页

作者： bong Jun Kwak Ho Joong Choi Young Kyoung You Dong goo kim Tae Ho Hong Department of Hepatobiliary and Pancreas Surgery Seoul St. Mary's Hospital College of Medicine The Catholic University of Korea Seoul Republic of Korea

Background:The difference in volume change in a pancreatic remnant according to the type of pancreaticoenterostomy after pancreaticoduodenectomy(PD)for long-term follow-up is ***,there are few studies that evaluate the difference in general nutritional status and pancreatic endocrine function,including new-onset diabetes mellitus(NODM)depending on the type of *** study aimed to compare serial pancreatic volume changes in pancreatic remnants between pancreatogastrostomy(PG)and pancreatojejunostomy(PJ)after PD and to evaluate the difference in general nutritional status and incidence of NODM between PG and ***:This study enrolled 115 patients who had survived for more than 3 years after *** were divided into the PG group and the PJ *** clinicopathologic factors were collected and *** calculated serial pancreas volume and pancreatic duct size precisely from preoperative stage to 5 years after surgery by image-processing software specifically designed for navigation and visualization of multimodality and multidimensional *** changes of albumin and body mass index(BMI)as related to general nutritional status were compared between the PG and PJ *** evaluate the incidence and risk factors of NODM following PD,subgroup analysis was performed in 88 patients who did not have diabetes ***:Most patient demographics were not significantly different between the PG group(n=45)and PJ group(n=70).There was no significant difference in volume reduction between the groups from postoperative 1 month to 5 years(PG group?18.21±14.66 mL versus PJ group?14.43±13.05 mL,P=0.209).But there was a significant difference in increased pancreatic duct size between the groups from postoperative 1 month to 5 years(PG group 1.66±2.20 mm versus PJ group 0.54±1.54 mm,P=0.007).There was no significant difference in the increase of total serum albumin between the groups for 5 years after surgery(PG group 0

关键词： Pancreaticojejunostomy pancreaticoduodenectomy(PD) nutritional status diabetes mellitus

Is the filamentary dark cloud GF 6 a star forming region?--Stability analysis and infrared properties

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Research in Astronomy and Astrophysics 2017年第12期17卷 77-88页

作者： Jaeheon kim Hyun-goo kim Sang Joon kim Bo Zhang Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China Korea Astronomy and Space Science Institute Daejeon 34055Korea Department of Astronomy and Space Science Kyung Hee UniversityYongin 17104Korea

We present the results of mapping observations and stability analyses toward the filamentary dark cloud GF 6. We investigate the internal structures of a typical filamentary dark cloud GF 6 to know whether the filamentary dark cloud will form stars. We perform radio observations with both 12CO（J =1–0） and 13CO（J =1–0） emission lines to examine the mass distribution and its evolutionary *** 13CO gas column density map shows eight subclumps in the GF 6 region with sizes on a sub-pc scale. The resulting local thermodynamic equilibrium masses of all the subclumps are too low to form stars against the turbulent dissipation. We also investigate the properties of embedded infrared point sources to know whether they are newly formed stars. The infrared properties also indicate that these point sources are not related to star forming activities associated with GF 6. Both radio and infrared properties indicate that the filamentary dark cloud GF 6 is too light to contract gravitationally and will eventually be dissipated away.

关键词： ISM:clouds ISM:molecules radio lines:ISM infrared:ISM Instabilities Turbulence

Automorphism groups of some algebras

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Science China Mathematics 2009年第2期52卷 323-328页

作者： PARK Hong goo LEE Jeongsig CHOI Seul Hee NAM Ki-bong Department of Mathematics Hanyang UniversitySeoul 133-791 Korea Department of General Studies and Education SamYuk University Cheongnyangi P.O.Box 118Seoul 130-650 Korea Department of Mathematics University of JeonjuChon-ju 560-759 Korea Department of Mathematics and Computer Sciences University of Wisconsin-WhitewaterWhitewater WI53190 USA

The automorphism groups of algebras are found in many papers. Using auto-invariance, we find the automorphism groups of the Laurent extension of the polynomial ring and the quantum n-plane (respectively, twisting polynomial ring) in this work. As an application of the results of this work, we can find the automorphism group of a twisting algebra. We define a generalized Weyl algebra and show that the generalized Weyl algebra is simple. We also find the automorphism group of a generalized Weyl algebra. We show that the generalized Weyl algebra Am,m+n is the universal enveloping algebra of the generalized Witt algebra W(m,m + n).

关键词： Laurent extension quantum n-plane (generalized) Weyl algebra automorphism auto-invariant 17B40 17B56

Evaluation of the performance of a soft X-ray charger for the bipolar charging of nanoparticles

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Particuology 2015年第1期13卷 165-169页

作者： Young Hun Yoon Choonkeun bong Dae Seong kim Department of Integrated Environmental Systems Pyeongtaek University GreenSolus Co. Global Frontier Center for Multiscale Energy Systems Seoul National University

The use of soft X-rays in a neutralizer represents an alternative technique that could replace conventional radioactive sources. In this study, we evaluated the charging characteristics of a soft X-ray aerosol neu- tralizer. In addition, the results from the evaluation of the soft X-ray charger were compared with results obtained using a neutralizer incorporating an 241 Am radioactive source. The tandem differential mobility analyzer technique was used previously to determine the size-dependent positive, negative, and neutral charge fractions of a soft X-ray neutralizer. This technique was used to show that the neutral fractions obtained using the soft X-ray charger agreed well with the predictions of bipolar diffusion charging the- ory, and that the soft X-ray charger could be used as a neutralizer for a scanning mobility particle sizer system.

关键词： Soft X-ray Neutralizer Bipolar charger Nanoparticle TDMA

Texture development and grain boundary phase formation in Ce-and Ce-La-substituted Nd-Fe-B magnets during hot-deformation process

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Journal of Materials Science & Technology 2022年第31期126卷 71-79页

作者： Ga-Yeong kim Tae-Hoon kim Hee-Ryoung Cha Sang-hyub Lee Dong-Hwan kim Yang-Do kim Jung-goo Lee Department of Magnetic Materials Korea Institute of Materials ScienceChangwon 51508Republic of Korea Department of Materials Science and Engineering Pusan National UniversityBusan 46241Republic of Korea R&D Center Star Group Ind.Co.Ltd.Daegu 42714Republic of Korea

In this study,the influence of Ce-and Ce-La-substitution for Nd in Nd-Fe-B magnets on their magnetic and microstructural changes in the course of the hot-deformation process was investigated to gain insight into further reducing the Nd content in fine-grained Nd-Fe-B hot-deformed *** found that the[001]texture and microstructure of the RE-rich grain boundary phases,which are the factors that de-termine the remanence and coercivity of hot-deformed magnets,were deteriorated by the Ce-and *** is because the volume fraction of the RE-rich liquid formed in the grain boundaries during the hot-press and hot-deformation decreased due to the Ce-and Ce-La-substitution,thereby in-creasing the friction between the 2:14:1 grains while the c-axes of grains were aligned by grain rotation and decreasing the RE concentration of grain boundary *** particular,the Ce-La-co-substitution further prevented the liquid formation within the grain boundaries of the magnets during hot-press and hot-deformation because the wettability of the RE-rich liquid on the 2:14:1 grains became poor when La was substituted for Nd in the 2:14:1 *** results indicate that there is room for further im-provement in both the remanence and coercivity of the Ce-and Ce-La-substituted magnets by intro-ducing additional liquid into the grain boundaries prior to hot-press and *** applying the Nd-Cu infiltration process to the melt-spun ribbons(intermediate infiltration,I-infiltration),both the remanence and coercivity of the Nd-saving(Nd 0.7 Ce 0.3)-Fe-B and(Nd 0.7 Ce 0.225 La 0.075)-Fe-B hot-deformed magnets were successfully improved.

关键词： Nd-Fe-B magnets Hot-deformation Nd-saving Ce-substitution La-substitution Infiltration

Anodic-biased titania nanotube growth in low-dielectric viscous media

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International Journal of Smart and Nano Materials 2013年第1期4卷 47-54页

作者： bong June Zhang Kwang Jin kim Low Carbon Green Technology Laboratory Department of Mechanical Engineering(MS312)University of NevadaRenoNV 89557USA

The influence was investigated of aqueous electrolytes and organic-based electrolytes on nanopore *** create well-defined nanotubes with a high aspect ratio,it is important to maintain equilibrium between field-assisted metal oxide dissolution and field-assisted water dissociation,which influence the temperature and pH levels in TiO_(2) nanotubes(TiO_(2) NTs).This sought after balance in the net reactions of the TiO_(2) NT growth can be achieved by choosing the appropriate electrolytes that are a relatively low dielectric viscous ***(η)and dielectrics(ε)can be a priority in designing the experiment since it is closely related to joule-heating,diffusion-driven metal ions dissolution and chemical etching of the metal *** and the hydrogen bonding ability are inter-correlated to the stability of the[TiF_(6)]^(2-) *** order to examine various electrolyte effects on the anodic-biased nanotube,different categories of electrolytes,each with different viscosity and dielectric properties,were incorporated in this study.

关键词： nanoporous material titanium dioxide nanotube thin film anodizing

Calculation of optimal current density of double side permanent magnet linear synchronous motor

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Journal of Central South University 2011年第1期18卷 165-170页

作者： JANG Ki-bong AN Ho-Jin kim Gyu-Tak School of Mechatronics Changwon National University

The use of design method considering a coil temperature to maximize the thrust density of a double side coreless permanent magnet linear synchronous motor(PMLSM) was *** optimal current density where the coil temperature reaches an allowable temperature with heat analysis was applied to a magnetic circuit *** optimal current density is verified whenever the design parameters of the motor are *** design parameters of the motor were applied to thrust *** this way,the optimal model,which is a reversal of the existing design method,is *** results were compared with the experimental data to verify their *** the convection heat transfer coefficient is applied to other models,the results of the analysis and test values show good *** method proposed has some limitations.

关键词： permanent magnet linear synchronous motor current density heat transfer temperature thickness of coil