중간세공탄소를 담체로 사용한 직접메탄을 연료전지용 Pt/C 촉매제조

하승백,김현수,최재식,정원섭,이호인 한국공업화학회 2003 응용화학 Vol.7 No.2

For the direct methanol fuel cell, the expensive cost of Pt is one of the most important factors. In this study, various kinds of support were synthesized and chosen for highly dispersed catalysts which need less amount of Pt and show higher activity. A mesoporous carbon was selected as a support which has 5 times larger specific surface area than Vulcan XC-72, a commercial support. Such a large surface area gave an advantage in the dispersion of Pt, but a disadvantage in electric conductivity which could be solved by increasing the carbonizaton temperature in the preparation of mesoporous carbon. These prepared mesoporous carbons were used as supports of Pt. Among the catalysts, the catalyst using mesoporous carbon carbonized at 1000 ℃ showed better activity than the catalyst using Vulcan XC-72 as a support showing the best activity. From the XRD analysis, the activity was proportional to the dispersion of Pt.

장기 입원환자의 구강위생상태에 관한 실태 조사연구

이백현,신승철 단국대학교 치의학연구소 1990 논문집 Vol.2 No.-

The author have studied the status of oral health survey & snyder test in order to find out oral health levels of medical hospitalized patients. 72 patients volunteers age of 20 to 40, hospitalized at department of general surgery or pediatric surgery in K & J hospitals located in Seoul were participated in this study. Oral health status & the oral health control methods examined 3 times periodically for 2 weeks interval. And the obtained results were analyzed and compared. 1. At 1st oral survey, the longer periods the patients had been hospitalized, the higher score of plaque index, calculus index, gingival index & periodontal index had presented comparatively. 2. As a longitudinal studies for patients, it was estimated that plaque index, calculus index, gingival index were changed with high score tendencies gradually. 3. In Snyder test, the longer for non-ambulated were performed the higher degree of caries activity were estimated more of less. 4. It was represented that daily tooth brushing frequency was reduced gradually in long term hospitalized patients otherwise there was no significance in statistically. 5. It was estimated that more frequencies be found in patients hospitalized in K hospital in which located at central region of Seoul city than those of in J hospital located up town region. So it would be represented that the less plaque index, claculus index & gingival index were founded at the patients hospitalized in K hospital. 6. It was recommended that special oral health program should be needed and special dental manpower might be required to promote dental health levels for long termed medically hospitalized patients.

피압수가 존재하는 연약점토지반 내에 연직배수재의 관입깊이에 따라 압밀거동에 미치는 영향

정성교,진현식,백승훈 동아대학교 건설기술연구소 1999 硏究報告 Vol.22 No.2

In the Yangsan area developed for housing complex the soft clay deposited as about 20 to 40 meters in thickness and there was the Artesian pressure of about 20kPa under the clay stratum. To investigate the consolidation behaviour due to partially or fully penetrating vertical drains in the clay layer, a finite element analysis was carried out in this study. As a result of analysis, it was shown that the consolidation rate and the final settlement for the case of fully penetrating vertical drains were faster and less than of partially penetration, respectively.

미세 물 흐름 측정장치의 개발과 상아세관액의 수력학에의 응용

이인복,김민호,김선영,장주혜,조병훈,손호현,백승호 大韓齒科保存學會 2008 Restorative Dentistry & Endodontics Vol.33 No.2

본 연구의 목적은 나노리터 수준의 물 흐름을 계측할 수 있는 장치를 개발하고, 상아질의 물 투과성을 측정하여 치아과민증 치료제와 상아질 접착제의 상아세관 밀폐효과를 알아보고자 하였다. 본 연구에서 제작한 미세흐름 측정장치는 첫째, 물의 흐름을 감지하는 모세관과 광 센서부, 둘째 물의 흐름을 추적하는 서보모터와 구동부, 셋째, 모터의 회전을 측정하여 물의 이동량으로 변화하는 엔코더와 컴퓨터 기록장치 등 세 부분으로 구성되어 잇다. 본 장비를 이용하여 교합면이 절단되어 노출된 상아질의 물 투과도와 치아과민증 치료제인 BisBlock과 자가부식형 상아질접착제인 Clearfil SE bond의 상아질 밀폐효과를 측정하여 다음과 같은 결과를 얻었다. 1. 나노리터 수준의 물 흐름을 측정할 수 있는 장치를 제작하였고, 이를 이용하여 상아질의 물 투과도를 측정할 수 있었다. 2. 삭제 후 노출 연마된 상아질은 0.84 - 15.2 nL/s의 물 투과도를 보였고 Oxalate 제재인 BisBlock 이나 자가부식형 접착제 Clearfil SE bond 적용시 투과도가 39.8 - 89.6% 감소하였다. This study was aimed to develop an instrument for real-time measurement of fluid conductance and to investigate the hydrodynamics of dentinal fluid. The instrument consisted of three parts: (1) a glass capillary and a photo sensor for detection of fluid movement, (2) a servo-motor, a lead screwand a ball nut for tracking of fluid movement, (3) a rotary encoder and software for data processing. To observe the blocking effect of dentinal fluid movement, oxalate gel and self-etch adhesive agent were used. BisBlock (Bisco) and Clearfil SE Bond (Kuraray) were applied to the occlusal dentin surface of extracted human teeth. Using this new device, the fluid movement was measured and compared between before and after each agent was applied. The instrument was able to measure dentinal fluid movement with a high resolution (0.196 nL) and the flow occurred with a rate of 0.84 to 15.2 nL/s before treatment. After BisBlock or Clearfil SE Bond was used, the fluid movement was decreased by 39.8 to 89.6%.

Livestock-Associated Methicillin-Resistant Staphylococcus aureus in Korea: Antimicrobial Resistance and Molecular Characteristics of LA-MRSA Strains Isolated from Pigs, Pig Farmers, and Farm Environment

Seung Hyun Back,Hong Sik Eom,Haeng Ho Lee,이기용,Kun Taek Park,Soo-Jin Yang 대한수의학회 2020 Journal of Veterinary Science Vol.21 No.1

The emergence of livestock-associated (LA)-methicillin-resistant Staphylococcus aureus (MRSA) in livestock animal has become a significant zoonotic concern. In the present study, we investigated nationwide prevalence of LA-MRSA across pork production chain including pig farms, slaughterhouses, and retail markets. A total of 40 MRSA strains were isolated during the investigation and the overall prevalence of MRSA was 3.4% (n = 37), 0.6% (n = 2), and 0.4% (n = 1) in pig farms, slaughterhouses, and retail markets, respectively. Multilocus sequence typing analyses revealed that the 2 most significant clonal lineages in pork production chain in Korea were ST398 (n = 25) and ST541 (n = 6). All of the 40 MRSA isolates were further characterized to investigate key genotypic and phenotypic correlates associated with the emergence and spread of clonal complex 398 (CC398; ST398, and ST541) LA-MRSA. Although the prevalence of swine-associated MRSA was still relatively low and mostly restricted to pig farms, multidrug-resistant CC398 LA-MRSA isolates with new spa types (t18102 and t18103) were identified as a major clonal lineage. The CC398 LA-MRSA strains tended to exhibit increased levels of multiple drug resistance (MDR) phenotype compared with non-CC398 MRSA strains. Of note, in comparison with non-CC398 MRSA isolates, CC398 LA-MRSA isolates exhibited significantly enhanced tetracycline (TET) and zinc resistance. These findings suggested that co-selection pressure associated with MDR phenotype, especially TET resistance, and zinc resistance may have played a significant role in the emergence and persistence of CC398 LA-MRSA in pig farms in Korea.

Prognostic significance of splenectomy during completion total gastrectomy in patients with remnant gastric cancer: propensity score matching analysis

Seung Hyun Back,Sung Eun Oh,Ji Yeong An,Min Gew Choi,Tae Sung Sohn,Jae Moon Bae,Jun Ho Lee 대한종양외과학회 2021 Korean Journal of Clinical Oncology Vol.17 No.2

Purpose: Splenectomy for patients with remnant gastric cancer has been controversial. The purpose of this study is to identify the impact of splenectomy in the treatment of remnant gastric cancer. Methods: We retrospectively analyzed 285 patients with remnant gastric cancer who underwent completion total gastrectomy with or without splenectomy in Samsung Medical Center, between September 1996 and December 2017. We used a 1:1 propensity score matching method for the analysis. The matching factors were age, sex, and pathologic stage. After the matching process, we compared the 5-year overall survival (OS) and the disease-free survival (DFS) between patients with and without splenectomy during completion total gastrectomy. Results: The median duration of follow-up was 58.0 months (range, 0–132 months). After propensity score matching, there were no statistically significant differences between the splenectomy group (n=77) and no splenectomy group (n=77) in terms of clinicopathological features. The 5-year OS rate between the no splenectomy and splenectomy group were not significantly different. There was no significant difference between 5-year DFS of the matched groups. Multivariate analysis revealed that splenectomy is not a significant prognostic factor in terms of 5-year OS (no splenectomy vs. splenectomy; 61.5% vs. 60.2%, P=0.884) or DFS (74.9% vs. 69.8%, P=0.880). Conclusion: Splenectomy has no impact on the OS and DFS in patients with remnant gastric cancer. Splenectomy during completion total gastrectomy may not be necessary.

복합운송용 LNG탱크컨테이너의 국내도입 활성화 방안 연구

배현옥(Hyun-Ok Bae),이계승(Kye-Seung Lee),백승진(Seung-Jin Back),하오근(Oh-Keun Ha),공현덕(Hyun-Duk Kong) 한국철도학회 2013 한국철도학회 학술발표대회논문집 Vol.2013 No.5

친환경 에너지로 각광받고 있는 LNG는 기타 에너지원에 비해 안전하고 저렴한 특징이 있다.이러한 혜택을 보다 많은 국민들에게 보급ㆍ확산을 해야 하지만 산간지역의 지리적 제약과 경제성 등의 사유로 인프라 구축이 어려우므로 도시지역과 산간 지역 간의 에너지 빈익빈 부익부 현상이 심화되고 있다. 이러한 문제점을 해결하기 위해 육상운송(철도ㆍ도로)과 해상운송에서 복합적으로 사용 가능하고 저장소로도 이용 가능한 LNG탱크컨테이너를 개발하였다. LNG 탱크컨테이너의 원활한 육상운송을 위해 시연사업 계획을 수립하고 운송 단계별 체크리스트를 기반으로 평택 LNG 기지에서 평창 알펜시아 리조트까지 육상운송 시연사업을 시행하였다. 이를 토대로 LNG 탱크컨테이너의 육상운송 가능성과 활성화 방안을 제시하였다. LNG which has been very popular as one of eco-friendly energy sources has a clear characteristics in that it is safe and cheap compared with other energy sources. It should be supplied and spread to many people so that they can enjoy this benefit. However, as it is difficult to establish necessary infrastructures due to geographical constraints in the mountain regions and economic feasibility, the polarization of wealth has been much worser over time. Under these circumstances, the study developed a LNG tank container which could complexly be used for land (railway and road) and maritime transportation and as a storage facility to solve this problem. The study established a demonstration project plan for a smooth land transportation of LNG containers and carried out a demonstration project for a land transportation from Pyeongtaek LNG base to Alpensia Resort in Pyeongchang based on a checklist by transportation stage. The study presented the possibility of transporting LNG tank container transportation by land and a revitalization plan.

X-band Linac for a 6MeV dual-head radiation therapy gantry

Lee, Seung Hyun,Shin, Seung-Wook,Lee, Jongchul,Kim, Hui-Su,Lee, Byeong-No,Lee, Byung-Chul,Park, Hyung-dal,Song, Ki-back,Song, Ho-seung,Mun, Sangchul,Ha, Donghyup,Chai, Jong-Seo Elsevier 2017 Nuclear Instruments & Methods in Physics Research. Vol.852 No.-

<P><B>Abstract</B></P> <P>We developed a design for a 6MeV X-band linear accelerator for radiation therapy in a dual-head gantry layout. The dual-head gantry has two linacs that can be operated independently. Each X-band linac accelerates electron bunches using high-power RF and generates X-rays for radiation therapy. It requires a versatile RF system and pulse sequence to accomplish various radiation therapy procedures.</P> <P>The RF system consists of 9.3GHz, 2MW X-band magnetron and associated RF transmission components. A test linac was assembled and operated to characterize its RF performance without beam. This paper presents these results along with a description of the gantry linacs and their operational requirements.</P>

Usage of By-product to Increase Alkalinity of Seawater and Effect of Alkalinity on the Efficiency of Flue Gas Desulfurization

( Seung-ki Back ),( Hyeon-ho Jo ),( Yong-chil Seo ),( Seong-heon Kim ),( Hyun-tae Jeong ),( Hee-chul Yoon ),( Jeong-hee Hong ) 한국폐기물자원순환학회(구 한국폐기물학회) 2015 한국폐기물자원순환학회 3RINCs초록집 Vol.2015 No.-

Many power plants tend to be built in place close to the seashore because large amount of cooling water is used. For existing desulfurization method using lime, lots of cost is needed to purchase of lime and transportation and disposal of discharged gypsum waste. Because of these reasons, a lot of research and application of desulfurization utility using seawater is actively being conducted. In this study, by-products from industrial combustion process were investigated as an alternative material to increase the alkalinity to utilize them for substituting agents of limestone or lime in wet scrubbing units. The effect of water-gas ratio and alkalinity of absorbing solution on the removal efficiency of flue gas desulfurization was investigated and found that alkalinity enhanced by industrial by-products and affected to SO2 removal efficiency. The results provided promising possibility for total alkalinity of seawater using by-products from coal-fired power plants.

Bioequivalence evaluation of glimepiride 2 mg tablets in healthy male Korean volunteers

Hyun-Ah Kang,Hea-Young Cho,Seung-Hee Back,Yong-Bok Lee 대한약학회 2004 大韓藥學會 總會 및 學術大會 Vol.2004 No.1