졸-겔법을 이용한$(Ba_{1-x}Sr_x)TiO_3$분말합성

김영석,김덕준,김환,Kim, Young-Seok,Kim, Duk-Jun,Kim, Hwan 한국재료학회 1992 한국재료학회지 Vol.2 No.2

본 연구에서는 $Ba(OH)_2{\cdot}8H_2O,\;Sr(OH)_2{\cdot}8H_2O$ 및 $Ti(i-OC_3H_7)_4$를 사용하여 졸-겔법에 의해 미세한 $(Ba_{1-x}Sr_{x})TiO_3$ 분말을 제조하였다. TEM 관찰, BET 비표면적측정 및 XRD회절도의 분석결과 $700^{\cric}C$에서 하소한 뚠말의 입자크기는 20~40nm이고 입방정상으로 존재하였다. 또한 XRD 회절도고부터 계산된 격자상수 및 (112)피크의 이동으로부터 고용체분말이 형성되었음을 확인할 수 있었다. 제조된 분말에서의 EDAX 분석을 통한 양이온들의 상대적인 비율 및 소결체에 대한 유전상수의 측정결과로부터 제조된 분말에서 양이온들의 분포가 입자단위에서 균질함을 예상할 수 있었다. Using $Ba(OH)_2{\cdot}8H_2O, \;Sr(OH)_2{\cdot}8H_2O$ and $Ti(i-OC_3H_7)_4$, fine $(Ba_{1-x}, \;Sr_{x})TiO_3$ powders were synthesized through sol-gel process. The particle size of the powders calcined at $700^{\cric}C$ proved to be 20-40nm by the observation of TEM micrographs and measurement of BET specific surface area. The analysis of XRD patterns showed that the phase of the powders was cubic, and it was identified with the lattice parameters determined through XRD patterns and the shift of (112) peaks that the solid solution powders were synthesized. It was expected through the analysis of relative ratio of cations and the uniformity of compositions in the powders examined by EDAX analysis and relative dielectric constant measurements for sintered body that the distribution of cations was uniform in particle unit.

탄소섬유를 이용한 600V 이하 저압 케이블의 전자파 차폐특성

김영석,김택희,김종민,송길목,김지연,김원석,곽동순,Kim, Young-Seok,Kim, Taek-Hee,Kim, Chong-Min,Shong, Kil-Mok,Kim, Ji-Yeon,Kim, Won-Seok,Kwag, Dong-Soon 대한전기학회 2017 전기학회논문지 Vol.66 No.1

This study used general carbon fibers(CF), which can be utilized for a low voltage cable screen, as well as metal-coated carbon fibers(MCF) to make cables and analyzed the properties of electromagnetic effectiveness. Both braid CF and MCF cables with 3,000 strands, 16 spindles, and braid density of 90% or over were adopted. The tape-type MCF specimens were spread into a tape(width: 15mm) using a hot melt to make a cable. The shield effectiveness was measured up to the 1GHz range in accordance with IEC 62153-4-6; braid shielded cables featured a superior shielding effect at 63dB than tape-type shielded cables. That was because the tape-type shielded cable has relatively more gaps and holes between carbon fibers than the braid type, resulting in a more inflow or emission of electromagnetic waves. In the case of braid cables, the characteristics of their electromagnetic waves were enhanced, with higher spindles and higher conductivity of carbon fibers. The shield effectiveness of the MCF shielded cable, however, was lower than that of tin-coated one.

단삼이 당뇨병성 신병증 Rat의 신기능 및 조직학적 변화에 미치는 영향

김영석,이병철,안세영,두호경,안영민,Kim, Young-Seok,Lee, Byung-Cheol,Ahn, Se-Young,Doo, Ho-Kyung,Ahn, Young-Min 대한한방내과학회 2008 大韓韓方內科學會誌 Vol.29 No.3

Objective : Diabetic nephropathy is the most common cause of end stage renal disease. AGE, $TGF-{\beta}1$ type IV collagen, and macrophage/monocyte infiltration are the main factors of diabetic nephropathy. We investigated the effects of Salvia miltiorrhiza on renal function and histopathological changes in streptozotocin(STZ)-induced diabetic nephropathy rat model. Methods : Diabetes was induced in male Sprague-Dawley rats(290${\pm}$10g) by injecting STZ(45mg/kg) into the tail vein. Rats were divided into 3 groups(n = 6): normal, control, and salvia. After 8 weeks of administration of Salvia miltiorrhiza extract on the Salvia group, we checked 24 hrs urine, blood biochemistry and renal tissue to evaluate renal function and histopathological changes by examining parameters including albuminuria, BUN, creatinine, cholesterol, LDL, TG, macrophage/monocyte antigen(ED-1), $TGF-{\beta}1$, AGE, and type IV collagen. Results : Salvia miltiorrhiza decreased the amount of 24hrs proteinuria, and inhibited histopathological changes of diabetic nephropathy including the expression and accumulation of various factors which could promote development of diabetic nephropathy. Conclusion : These findings suggest that Salvia miltiorrhiza might protect the renal function and inhibit the development of renal injury by regulating factors including AGE, $TGF-{\beta}1$ Type IV collagen, macrophage and monocyte infiltration. So Salvia miltiorrhiza can be used for diabetic patients to prevent the progression of diabetic nephropathy.

우리나라 공공도서관의 이용변화 추이 분석 및 대응방안 연구

김영석,Kim, Young-Seok 한국도서관정보학회 2021 한국도서관정보학회지 Vol.52 No.2

This study aims to analyze the trend of library use according to the expansion of public library infrastructure in Korea, and to search for new roles and services of libraries based on the results of the study. Using the statistical analysis, literature review and partially interview method, the number of borrowers and loans from 2009 to 2019 were analyzed. The result of the survey reveals that the number of public libraries increased by 61.3% during the survey period, while the number of borrowers decreased by 57.5%, and the number of book loans increased only by 18.2%. The result of the analysis claims that the causes of the decrease in the number of materials borrowers were an error in the process of inputting statistics and manipulating the number of book loans by the local library. The population of children and young adults decreased during the survey period, which led to a decrease in the number of children and young adult borrowers. The result of the study reveals that the increase in the use of public libraries in Korea, like other advanced countries, is stagnant. The following new roles and services are suggested for the development of public libraries: Libraries expand non-face-to-face services and electronic resources, and promote their use. Libraries expand cultural and lifelong learning programs further. 본 연구는 우리나라 공공도서관 인프라 확충에 따른 도서관 이용의 변화 추이를 분석하고, 그 결과에 따라 도서관의 새로운 역할과 서비스를 모색하는 데 그 목적이 있다. 통계분석과 문헌조사법 그리고 부분적인 인터뷰 방법을 사용하여 2009년부터 2019년까지의 공공도서관 대출자 수 및 대출 책 수를 조사·분석하였다. 조사 결과 도서관 수는 조사기간 동안 61.3% 증가한 반면, 대출자 수는 57.5% 감소하였고, 대출 책 수는 18,2% 증가에 그쳤다. 분석 결과 대출자 수감소 원인은 통계 입력 과정에서의 착오와 도서관에서 행해진 대출실적 부풀리기로 밝혀졌다. 조사기간 동안 어린이와 청소년 인구가 감소하였는데, 이것은 어린이와 청소년 대출자 수 감소로 이어졌다. 연구 결과 우리나라의 공공도서관 이용은 다른 선진국처럼 그 증가가 정체되고 있는 것으로 밝혀졌다. 공공도서관의 발전을 위해 다음과 같은 새로운 역할과 서비스를 제안한다: 도서관은 비대면 서비스 및 비실물자료를 확대·확충하고 그 이용을 활성화 시킨다. 문화 및 평생교육 프로그램을 더욱 확대한다.

6-propyl, 2-thiouracil로 유발된 갑상선 기능저하증 동물모델에서 파극천이 갑상선 호르몬 및 갑상선 조직에 미치는 효능

김영석,안세영,안영민,이병철,Kim, Young-Seok,Ahn, Se-Young,Ahn, Young-Min,Lee, Byung-Choel 대한한방내과학회 2011 大韓韓方內科學會誌 Vol.32 No.3

Objectives : Hypothyroidism is the most common pathological disease of the endocrine system. Morinda Officinalis Radix has been used in treatment of Yang deficiency. In this study, we investigated the therapeutic effects of Morinda Officinalis Radix on a rat model of hypothyroidism induced by 6-propyl, 2-thiouracil (PTU). Methods : Two-month-old Sprague-Dawley male rats were used with injection of PTU which induced rats into hypo-thyroidism. During 2 weeks, rats were treated with Morinda Officinalis Radix and thyroxine. Body weights were checked every week, the after 4 weeks, biochemical analyses were performed. The levels of T3, T4 and TSH was measured by EILSA. Results : In the Morinda Officinalis Radix group, we could observe the level of T4 significantly increased and TSH level significantly decreased. Conclusions : Morinda Officinalis Radix could help the thyroid to produce thyroid hormones under PTU suppression. There is no harm effect on liver and kidney function, or other metabolism. According to these results it could help to treat hypothyroidism patients and relieve their symptoms.

영국 공공도서관의 어린이.청소년 독서 프로그램 운영 사례 연구 - Stories from the Web 분석을 중심으로 -

김영석,Kim, Young-Seok 한국비블리아학회 2007 한국비블리아학회지 Vol.18 No.1

This study aims to examine and analyse 'Stories from the Web(SFW)' in order to assist the development of reading programs for children and young adults in Korea. The British public libraries operate a reading program of 'Stories from the Web(SFW)' which is a web-based reading program for children 0 to 14 years old. SFW is not a reading program that enables children to read books on-line. but motivates children to read books in public libraries.

염수 및 분진에 의한 고분자 절연물의 표면누설전류 특성과 사고 위험성

김영석,송길목,정진수,정종욱,김선구,Kim, Young-Seok,Shong, Kil-Mok,Jung, Jin-Su,Jung, Jong-Wook,Kim, Sun-Gu 한국조명전기설비학회 2007 조명·전기설비학회논문지 Vol.21 No.8

It is necessary to study on the prevention and the management of electrical facilities because the electrical fault took place at the dust occurrence area due to environmental pollution. In particular, the dust accumulates easily on insulation material which is exposed an external long time. Therefore, we measured surface leakage current and surface variation of insulation material due to the dust and salt-water. From the results, the surface of bakelite is bad effect for salt-water than other material. The surface leakage current increases by repeated salt-water pollution and the surface of material is carbonized with arc occurrence. Also, it is need to variation of surface coating and shape of material to repress a leakage current on electrical material. 환경오염이 심한 분진 발생지역에서는 전기 사고가 자주 발생하기 때문에 전기설비에 대한 유지관리와 예방에 대한 연구가 필요하다. 특히 외부에 전기절연물이 장기간 노출되면, 쉽게 분진이 축적되고 수분, 습기 등에 의한 누설전류의 발생으로 전기사고에 이르게 된다. 따라서 본 연구에서는 분진, 염수 등에 의한 전기설비 절연재료 표면변화와 표면 누설전류를 측정하였다. 측정결과로부터 베이클라이트의 표면이 다른 재료보다 염수에 대한 영향이 심하였다. 또한 베이클라이트 표면 누설전류는 반복되는 염수 오염에 의해 증가하고 재료표면은 미소아크가 발생하고 탄화되었다. 따라서 절연물에서의 누설전류를 억제하기 위해서는 재료의 형태 및 표면 코팅 등이 변화가 필요하다.

발치 후 젤라틴 스폰지와 혈소판 농축 혈장이 치조제 보존 및 골 형성에 미치는 영향

김영석,권경환,차수련,민승기,Kim, Young-Seok,Kwon, Kyung-Hwan,Cha, Soo-Yean,Min, Seung-Ki 대한악안면성형재건외과학회 2005 Maxillofacial Plastic Reconstructive Surgery Vol.27 No.3

The placement of different graft materials and/or the use of occlusive membranes to cover the extraction socket entrance are techniques aimed at reducing alveolar ridge resorption and enhancing bone formation. However, in spite of its clinical advantage, the use of graft materials in fresh extraction socket has been questioned because particles of the grafted material have been found in alveolar sockets with fibrous union. The purposes of this study were to evaluate whether alveolar ridge resorption following tooth extraction could be reduced and bone formation could be enhanced by the application of absorbable gelatin spongy or gelatin spongy soaked with platelet rich plasma(PRP) used as a space filler in clinical and radiographic aspects. Eighty patients who were scheduled for extraction of both third molars were participated and carried out by one experienced surgeon. Following extraction of teeth, one extracted socket were treated with gelatin spongy as an experimental group A and the other were treated with gelatin spongy and PRP as an experimental group B. The routine extracted socket were healed without any treatment as a control group. From the period of extraction to 12 weeks postoperatively, we examined the clinical course and radiographic evaluation on socket at regular interval. Both experimental groups showed faster wound healing process than control clinically. Vertical gingival height of the extraction socket were less changed statistically in both experimental groups than control. The horizontal width change of the extraction socket were not significant statistically in any group. Radiographic changes of the alveolar bone height were less changed in both experimental groups and bone density were showed higher than control. There were a little difference between experimental group A and B. In conclusion, absorbable gelatin sponge and with PRP were considered as having preservation effects of extraction socket and stimulation of bone formation process after extraction.

영국 공공도서관 건축의 발전 과정에 관한 연구

김영석,Kim, Young-Seok 한국비블리아학회 2009 한국비블리아학회지 Vol.20 No.3

The British public library services could be provided earlier than other countries as a result of the Industrial Revolution which was started in the U.K. earlier than other countries. Britain has steadily been building public library infrastructure during the last 150 years and currently maintains the highest level of public library services and operation. Until the 20th century, each local government in Britain remodeled other buildings into libraries and adopted a small and simple form of library building to build more libraries and also to help the convenient use of library, while minimizing the cost of library construction. The construction of public libraries of local governments was supported by the Public Libraries(and Museums) Act enacted in 1850. Korea is in an effort to build more public libraries. The study suggests that a small and simple form of library building should be constructed in order to build more public libraries with minimum costs.

22.9[kV]이하 XLPE 전력케이블의 열 충격 시험 및 절연파괴 특성

김영석,송길목,김선구,Kim, Young-Seok,Shong, Kil-Mok,Kim, Sun-Gu 한국조명전기설비학회 2008 조명·전기설비학회논문지 Vol.22 No.4

It is impossible to database(DB) the patterns of power cable events and cause analysis of faulted cable because the product liability(PL) law have been enforced in Korea, since 2002. In additions, simulation and pattern of power cable events are needed for DB system under accelerated deterioration. In this paper, we tested for resistance to cracking of cable below the 22.9[kV] class due to thermal stresses. This method of exam is following IEC 60811-3-1(Common test methods for insulating and sheathing materials of electric cables). From the results, The 22.9[kV] class A power cable was discolored on the surface and significantly reduced in the longitudinal direction. As the thermal weight properties of A power cable was definitely varied, we are able to guess the problem of manufacture. If the cable was defect by the manufacture, the victims would be able to claim for damage in the PL system. 2002년부터 시행되어오고 있는 제조물 책임법에 의해 사고케이블의 원인분석과 사고패턴에 대한 데이터베이스화가 중요하다. 더욱이 가속열화상태에서 전력케이블 사고의 패턴 및 모의실험은 데이터베이스 시스템 구축에 필요하다. 본 논문에서는 열 열화 따른 22.9[kV]이하 케이블의 열 충격시험을 수행하였다. 이 시험은 IEC60811-3-1에 따른다. 시험결과로부터, 22.9[kV]급 A사 전력케이블은 표면이 변색되었고 길이방향으로 급격하게 감소되었다. 특히, A사 전력케이블의 열 중량 특성이 심하게 변함에 따라, 케이블 제조상의 문제일 것이라 추측된다. 만약 전력케이블의 제조상의 결함에 의한 것이라면, 피해자들은 PL환경 하에 손해배상을 받을 수 있을 것이다.