교외 주거지역 개발방향에 관한 연구 : 부산시 개발제한구역 집단취락을 대상으로

최열,김지현,이규환 釜山大學校 都市問題硏究所 2003 都市硏究報 Vol.14 No.-

In recent years, there has been a growing concern about the quality of life, especially residential environment as well as housing settings. The research reported in this study examines sources of residential environment and regional development among dwellers in suburban area. In Busan, suburban area had been kept for restricted development zone and have been a growing hopes for advanced residential environment and regional development. To accomplish this purpose, the methods of this study were based to refer to sundry records, and to inquiry with questionnaries. As a result analyzed questionnaires, they preferred regional development and rehabilitation of their housing to preservation around natural environment for the most respondents(78.40%). And it is very important to develop suburban residential area that it is close relation with their neighborhood, community size by 30~100 households, infrastructure. Their preference for regional development concept is garden city and venture town to silver town or so. It is desired that someone carry out further work on the suburban residential area for increasing community satisfaction.

고유량 고효율 혈액투석막 재사용의 임상경험

조현경,김승정,임병국,정혁준,최영일,마경애,신규태,김흥수,김도헌 대한신장학회 2001 대한신장학회잡지 Vol.20 No.3

Simvastatin이 골결손부 회복에 미치는 영향

강정호,김규태,최용석,이현우,황의환 대한구강악안면방사선학회 2008 Imaging Science in Dentistry Vol.38 No.3

Purpose : To observe and evaluate the effects of Simvastatin-induced osteogenesis on the wound healing of defective bone. Materials and Methods : 64 defective bones were created in the parietal bone of 32 New Zealand White rabbits. The defects were grafted with collagen matrix carriers mixed with Simvastatin solution in the experimental group of 16 rabbits and with collagen matrix carriers mixed with water in the controlled group. The rabbits were terminated at an interval of 3, 5, 7, and 9 days, 2, 4, 6, and 8 weeks after the formation of defective bone. The wound healing was evaluated by soft X-ray radiography. The tissues within defective bones were evaluated through the analysis of flow cytometry for the manifestation of Runx2 and Osteocalcin, and observed histopathologically by using H-E stain and Masson’s trichrome stain. Results : 1. In the experimental group, flow cytometry revealed more manifestation of Runx2 at 5, 7, and 9 days and Osteocalcin at 2 weeks than in the controlled groups, but there was few difference in comparison with the controlled group. 2. In the experimental group, flow cytometry revealed considerably more cells and erythrocytes at 5, 7, and 9 days in comparison with the controlled group. 3. In the experimental group, soft x-ray radiography revealed the extended formation of trabeculation at 2, 4, 6, and 8 weeks. 4. Histopathological features of the experimental group showed more fibroblasts and newly formed vessels at 5 and 7 days, and the formation of osteoid tissues at 9 days, and the newly formed trabeculations at 4 and 6 weeks. Conclusion : As the induced osteogenesis by Simvastatin, there was few contrast of the manifestation between Runx2 and Osteocalcin based on the differentiation of osteoblasts. But it was considered that the more formation of cells and erythrocytes depending on newly formed vessels in the experimental group obviously had an effect on the bone regeneration.

다발성 골수종에서 저용량 thalidomide, cyclophosphamide, dexamethasone (TCD) 요법의 효과

류충헌,정재현,고정해,장제혁,박영진,최규남,박봉수,이상민,주영돈 인제대학교 2008 仁濟醫學 Vol.29 No.-

Background and Objectives : The immunomodulatory drug thalidomide can inhibit angiogenesis and induce apoptosis in experimental models. It can also induce marked and durable response in newly diagnosed myeloma patients. Thalidomide has been used at doses ranging from 200 to 800 mg with significant toxicity. No data are available on the impact of low-dose thalidomide, cyclophosphamide and dexamethasone as initial therapy for myeloma patients. Design and Methods : To address this issue, newly diagnosed myeloma patients were treated with 50 mg/day thalidomide continuously and cyclophosphamide 150 mg/m², days 1-4 and dexamethasone 20 mg/m², days 1-5 and day 15-19, every month. Between October 2005 and October 2006, 14 patients (median age 54.5 years) were treated with low-dose thalidomide, cyclophosphamide and dexamethasone. Results : After a minimum of two cycles of treatment, 5 patients (55.5%) showed a partial remission. After four cycles of treatment, 10 patients (83.3%) showed a partial remission (n=6) and complete remission (n=4). After a median follow-up of 15.4 months, 1 year overall survival rate was 82.0%. Thalidomide was well tolerated without serious toxic effects. Conclusions : The combination of low-dose thalidomide, cyclophosphamide and dexamethasone demonstrates favorable response rate and 1 year overall survival rate in newly diagnosed myeloma. Severe toxicities were not seen with this combination.

Operating Area Extension of Surface Mounted Permanent Magnet Motor by LC Network

Hyeon-gyu Choi,Jung-Ik Ha 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

The maximum operable speed of a surface mounted permanent magnet motor is determined by the maximum available motor terminal voltage. In the conventional drive system using a three-phase voltage source inverter, the higher maximum motor terminal voltage can be obtained by boosting the DC link voltage such as a boost converter or Z-source inverter. However, all the devices and circuit should be redesigned because of the higher isolation length. This paper proposes the drive method for a surface mounted permanent magnet motor using a LC power network. LC network is placed between the motor terminal and the output terminal of inverter. The maximum operable speed in the proposed drive system is higher than that in the conventional drive system while keeping the same rated torque. The design method of LC network and the system analysis are presented. The effectiveness of the proposed method is verified by the experimental results.

Efficacy of synthesis conditions on functionalized carbon nanotube blended cellulose acetate membrane for desalination

Choi, Hyeon-gyu,Yoon, Sang Hyeon,Son, Moon,Celik, Evrim,Park, Hosik,Choi, Heechul Informa UK (Taylor Francis) 2016 Desalination and Water Treatment Vol.57 No.16

<P>Cellulose acetate membrane has been applied to reverse osmosis for desalination due to chlorine tolerance and biofouling resistance. Since it requires optimized synthesis condition for application, we investigated the effect of different conditions on membrane performances. It was found that polymer concentration, solvent ratio, and evaporation time were critical to determine membrane selectivity and permeability. Based on the study, optimized conditions were obtained, which were 14 wt% of polymer concentration, 1:2.(of ratio of 1,4-dioxane to acetone, and 30 s of evaporation time. Further, functionalized multi-walled carbon nanotubes (MWCNTs) were applied to the optimized bare membrane in order to enhance the performances. The composite membranes were characterized by fourier transform infrared spectroscopy, scanning electron microscopy, and contact angle measurement. It was found that the MWCNTs influenced the morphology and surface chemistry of the membrane. This study could contribute to develop a commercial composite RO membrane with nanomaterial for desalination application.</P>

Integrating seawater desalination and wastewater reclamation forward osmosis process using thin-film composite mixed matrix membrane with functionalized carbon nanotube blended polyethersulfone support layer

Choi, Hyeon-gyu,Son, Moon,Choi, Heechul Elsevier 2017 CHEMOSPHERE - Vol.185 No.-

<P><B>Abstract</B></P> <P>Thin-film composite mixed matrix membrane (TFC MMM) with functionalized carbon nanotube (fCNT) blended in polyethersulfone (PES) support layer was synthesized via interfacial polymerization and phase inversion. This membrane was firstly tested in lab-scale integrating seawater desalination and wastewater reclamation forward osmosis (FO) process. Water flux of TFC MMM was increased by 72% compared to that of TFC membrane due to enhanced hydrophilicity. Although TFC MMM showed lower water flux than TFC commercial membrane, enhanced reverse salt flux selectivity (RSFS) of TFC MMM was observed compared to TFC membrane (15% higher) and TFC commercial membrane (4% higher), representing membrane permselectivity. Under effluent organic matter (EfOM) fouling test, 16% less normalized flux decline of TFC MMM was observed compared to TFC membrane. There was 8% less decline of TFC MMM compared to TFC commercial membrane due to fCNT effect on repulsive foulant–membrane interaction enhancement, caused by negatively charged membrane surface. After 10 min physical cleaning, TFC MMM displayed higher recovered normalized flux than TFC membrane (6%) and TFC commercial membrane (4%); this was also supported by visualized characterization of fouling layer. This study presents application of TFC MMM to integrated seawater desalination and wastewater reclamation FO process for the first time. It can be concluded that EfOM fouling of TFC MMM was suppressed due to repulsive foulant–membrane interaction.</P> <P><B>Highlights</B></P> <P> <UL> <LI> TFC MMM was synthesized with fCNT-blended PES layer. </LI> <LI> TFC MMM was firstly applied to integrating seawater desalination & wastewater reclamation FO process. </LI> <LI> Performances of TFC MMM were enhanced in FO test. </LI> <LI> EfOM fouling resistance was enhanced for TFC MMM due to electrostatic repulsion. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Eff ects of displaying social enterprise certification information on consumers’ product evaluations and purchase intentions

Gyu-Hyeon Choi,김준용 한국마케팅과학회 2016 마케팅과학연구 Vol.26 No.2

This study examines how, in Korea, displaying the social enterprise certification logo and/or the information about the socially vulnerable employees affects consumers’ product evaluations and purchase intentions, especially when consumers have different general attitudes towards the vulnerable groups employed. The findings of an experiment showed that displaying the social certification logo on product labels always affected our participants’ purchase intentions for products positively, even when the label also disclosed the information that the product might be produced by employees who belong to socially vulnerable groups towards whom the participants had negative general attitudes. In addition, disclosing the information about the socially vulnerable groups the company hired affected the participants’ product purchase intentions in accordance with the valence of the attitudes the participants held towards the socially vulnerable groups. However, the participants’ evaluations of the product were not influenced by either the certification logo or the information about the employees.

Evaluation of Flexural Performance According to the Plywood Bonding Method of Ply-Lam CLT(Ply-lam CLT의 합판 접합방식에 따른 휨 성능 평가)

( Gyu Woong Choi ),( Seung Min Yang ),( Hyun Jae Lee ),( Jun Ho Kim ),( Kwang Hyeon Choi ),( Seog Goo Kang ) 한국목재공학회 2021 목재공학 Vol.49 No.2

본 연구에서는 층재 수종과 길이방향의 합판 접합방식과 접합부의 접착제 도포 여부에 따른 휨 성능 및 파괴 양상 분석을 통하여 합판을 코어로 사용한 CLT에 적합한 합판의 접합 방식을 최적화 하고자 하였다. 더글라스 퍼 층재의 경우 길이방향 접합에 의해 휨탄성계수 약 11.5% 감소, 휨강도는 접착제 도포 및 접합방식에 따라 증가 또는 감소하였다. 접착제 미도포 butt joint, 접착제 도포 half lap joint, butt joint 조건이 최적조건으로 도출 되었다. 낙엽송 층재의 경우 길이방향 접합에 의해 휨강도는 약 15%, 휨탄성계수는 약 40% 감소하였으며 접합방식에 따른 차이를 나타내지 않았다. half lab joint와 tongue & groove joint 사용 시 합판 층의 접합부에서 휨에 파괴를 1차적으로 방지해줌으로써 중층의 층재로 전달되는 하중을 감소시켜 주는 것으로 판단된다. 본 연구 결과를 통해 Ply-lam CLT 제조과정에서 낙엽송 층재를 사용하는 경우 접합방법에 따른 차이를 나타내지 않았으며 더글라스퍼 층재를 사용할 경우 butt joint와 half lap 접합 방식이 적합할 것으로 판단된다. The purpose of this study is to optimize the bonding method of the plywood suitable for cross-laminated timber (CLT) with plywood as a core by analyzing the flexural performance and failure mode according to the lamina species, the method of bonding plywood in the longitudinal direction, and whether or not adhesive is applied to the joint. In the case of the Douglas fir lamina layer, the modulus of elasticity decreased by about 11.5% due to longitudinal bonding, and the modulus of rupture increased or decreased according to the adhesive application and bonding method. The optimal conditions were derived as the butt joint without adhesive, half lap joint with adhesive, and butt joint. In the case of the larch lamina layer, the modulus of rupture and the modulus of elasticity decreased by about 15% and 40%, respectively. When using the half lab joint and tongue & groove joint, it is believed that it reduces the load transmitted to the middle layer by primarily preventing the failure on flexure at the joint of the plywood layer. From the results of this study, the larch lamina layer used in the manufacturing process of Ply-lam CLT did not show any difference based on the bonding method. Butt joint and half lap joint bonding method are determined to be suitable when using Douglas fir lamina layer.

Dynamic current control using synchronous pulse-width modulation for permanent magnet machines

Choi, Hyeon-gyu,Ha, Jung-Ik The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.2

It is difficult to use the conventional fixed sampling pulse-width modulation (PWM) method in a motor drive system due to the harmonics and beat phenomenon when the number of switchings is low. Synchronous PWM is a solution to overcome these problems. However, it is difficult to implement a closed-loop current controller, since synchronous PWM only has merits when the switching frequency is synchronized with the operation speed. This paper proposes a closed-loop current controller for synchronous permanent magnet machines which are driven by synchronous PWM. The proposed controller uses the concept of variable time step control. The control variables are the sampling time interval and the output voltage magnitude. The proposed controller dynamically controls the dq-currents, while the steady-state merits of the synchronous PWM are maintained. This paper presents the design procedures and a dynamic analysis of the proposed current controller. The effectiveness of the proposed method is verified by experimental results.