SOL-GEL法에 依한 LAS系 結晶化유리의 製造에 있어서 租成比유리의 特性에 미치는 影響

김봉걸,양중식,조훈성,권창오,박경호 慶熙大學校 材料科學技術硏究所 1990 材料科學技術硏究論集 Vol.3 No.-

The purpose of this study is to investigate into the physical properties of Li₂O-Al₂O₃-nSiO₂ (LAnS) system of crystallized glass prepared by sol-gel method according to the composition ratio of LAnS. In order to find the crystallization temperature as well as the state of crystalline, differential thermal analysis and X-ray diffraction analysis were examined. The results obtained are as follows : 1. Gelling time became longer as increasing the composition ratio of SiO₂ and also found that it became faster as increasing the additive amount of water. Also, additive amount of water required for the gellation was above four times of the theoretical amount of water required hydrolysis. 2. Surface area and mean pore size became larger as increasing the composition ratio of SiO₂ and for LA4S dried gel, surface area was 331.1m^(2)/g, mean pore size distributed about 5nm and 30-50nm. 3. The crystallization temperature is high as increasing the composition ratio of SiO₂ and for LA4S, crystallization temperature is 800℃. Also, LA4S formed at 800℃ for the crystalline phase of β-eucryptite and at 900℃ for crystalline phase of β-spodumene.

광중합형 구치부 수복재료의 중합수축량과 중합수축력

박성호,이순영,조용식,김수선,이창재,김영주,이봉희,이광성,노병덕 大韓齒科保存學會 2003 Restorative Dentistry & Endodontics Vol.28 No.4

The purpose of present study was to evaluate the polymerization shrinkage stress and amount of linear shrinkage of composites and compomers for posterior restoration. For this purpose, linear polymerization shrinkage and polymerization stress were measured. For linear polymerization shrinkage and polymerization stress measurement, custom made Linometer (R&B, Daejon, Korea) and Stress measuring machine was used (R&B, Daejon, Korea). Compositers and compomers were evaluated; Dyract AP (Dentsply Detrey, Gumbh, German) Z100 (3M Dental Products, St. Paul, USA) Pyramid (Bisco, Schaumburg, USA) Synergy Compact (Coltene, Altstatten, Switzerland), Heliomolar (Vivadent/Ivoclar, Liechtenstein), and Compoglass (Vivadent Ivoclar/Liechtenstein) were used. 15 measurements were made for each material. Linear polymerization shrinkage or polymerization stress for each material was compared with one way ANOVA with Tukey at 95% levels of confidence. For linear shrinkage ; Heliomolar, Surefil<Synergy Compact, Z100<Dyract AP<Pyramid, Compoglass F (p<0.05) For Shrinkage stress ; Heliomolar < Z100, Pyramid<Synergy Compact, Compoglass F<Dyract AP<Heliomolar HB, Surefil (p<0.05)

뇌수술 시 과호흡과 만니톨의 투여가 뇌혈류와 뇌산소대사에 미치는 영향

김지헌,김경식,문봉기,조경기,신용삼,이영주,김진수 대한마취과학회 2002 Korean Journal of Anesthesiology Vol.43 No.4

Background: There are therapies to lower intracranial pressure (ICP) including head elevation, hyperventilation, diuretics injection, intravenous mannitol, hypothermia, cerebrospinal fluid drainage, and cerebral resection in neurosurgical patients. However in recent reports, hyperventilation followed by mannitol administration may lead to cerebral ischemia. Therefore, we investigated the effect of 0.5-1.0 g/kg mannitol administration on jugular venous oxygen saturation (SjVO_2) and cerebral arterial-jugular venous oxygen content difference (AVDO_2) at PaCO_2 25-30 mmHg and 35-40 mmHg in patients undergoing neurosurgery. Methods: we studied 17 patients undergoing neurosurgery in the Ajou University Hospital. Anesthesia was induced with fentanyl, midazolam, thiopental, and vecuronium, and maintained with )_2-Air-Isoflorane, a continuous infusion of fentanyl, and vecuronium. Patients were divided into two groups. Group 1 (n = 10) which is PaCO_2 25-30 mmHg and Group 2 (n = 7) which is PaCO_2 35-40 mmHg by controlling ventilator. Measurements of SjVO_2 and AVDO_2 in following time intervals: Ⅰ = preinjection of mannitol, Ⅱ = postinjection 20 minutes of mannitol, Ⅲ = postinjection 40 minutes of mannitol were obtainde for each group. 0.5-1.0 g/kg mannitol was administered intravenously just at duramater opening. Results: Hemodynamics and hematologics were not significantly different among the two groups. SjVO_2 of each group are as follows; Group 1; Ⅰ (70.3 ± 8.1%), Ⅱ (66.3 ± 6.9%), Ⅲ (69.1 ± 7.9%) and Group 2; Ⅰ (78.6 ± 7.4%), Ⅱ (75.1 ± 8.1%), Ⅲ (76.0 ± 11.2%), Hyperventilation significantly decreased SjVO_2- AVDO_2 was not significantly different but SjVO_2 in Ⅱ was significantly decreased compared with Ⅰ and Ⅲ in Group 1 (20% patients). Conclusions: Mannitol produced a change of SjVO_2 during hyterventilation. Therefore, intravenous mannitol during hyperventilation should be given cautiously according to the patients status because it may cause cerebral ischemia in critical patients. (Korean J Anesthediol 2002; 43: 462~467)

한우, 칡소 및 제주 흑우 Calpain-Calpastatin 유전자 다양성

이승환,김승창,조수현,최봉환,Aditi Sharma,임다정,당창권,장선식,김재환,고문석,양보석,강희설 충남대학교 농업과학연구소 2013 농업과학연구 Vol.40 No.2

The aim of study was to investigate genetic diversity for the calpain/calpastatin gene in three Hanwoo breeds [(Brown (n=62), Brindle (n=81) and Jeju Black (n=30)]. Random samples from three breeds of Hanwoo were selected and genotyped for the 7 SNPs of calpain/calpastatin using TaqMan method. Allele frequencies were investigated for CAPN1/CAST gene. Allele frequency of CAST2 SNP was 0.75, 0.59 and 0.22 for Brown, Brindle and Jeju black, respectively. The CAST3 revealed allele frequency of 0.59 and 0.57 in Brown and Jeju Black, while it showed very low allele frequency (0.07) in Brindle. In particular, favorable allele (G allele) for the CAPN1-2 SNP which was shown a strong association with tenderness in Taurine and Indicine cattle revealed 16% and 17% higher allele frequency in Brown Hanwoo (0.82) comparing Brindle (0.66) and Jeju Black Hanwoo (0.65). AMOVA demonstrated that among population variance occupied only 10% of total variance and among individual variance was 0%, while within individual variance was 90% of total variance. This result showed that population effect contributed very small portion of genetic to these three Hanwoo breeds, while within individual variance contributed large portion of genetic diversity within these Hanwoo breeds. In conclusion, three Hanwoo breeds (Brown, Brindle and Jeju black) showed a genetically homogeneous based on the 7 SNPs of CAPN1/CAST gene and it came from same ancestor to form modern Hanwoo breed.

구속된 비행 청소년들의 석방 후 6개월 이내 재범의 예측요인

서동혁,정선주,손창호,김원식,고승희,함봉진,조성진,김영기,이중재 大韓神經精神醫學會 2001 신경정신의학 Vol.40 No.3

연구목적 : 본 연구는 범법행위로 인해 검참에 구속된 청소년들의 6개월 이내 재범여부를 예측할 수 있는 요인을 분석함으로써 재범의 가능성이 높은 청소년들을 조기에 선별하여 적절한 중재를 시행하기 위한 목적으로 시행되었다. 방 법 : 검찰에 구속된 후 교도소나 소년원에 수감되지 않고 석박된 남자 청소년 125명을 대상으로 하였다. 범죄기록 검토를 통해 사회인구학적, 범죄관련 변인들에 대해 조사하였고, 가족환경 및 부모양육태도, 정신병리, 성격장애, 도덕발달수준 등과 연관된 변인을 알아보기 위해, 부모-이동 갈등해결척도(CTSPC), 한국판 가정환경척도(FES), 한국형 부모양육행동척도, 간이정신진단검사(SCL-90-R), Beck 우울증척도, Beck 불안 척도, 한국판 청소년용 도덕발달수준 평가도구와 한국판 성격장애검사(PDQ-R)를 시행하였다. 결 과 : 전체 연구대상 125명 중 55명 (44%)이 석방 후 6개월 이내에 1회 이상의 재범을 행하였다. 재범군은 비재범군에 비해 구속당시 나이가 어리고, 신체적 학대력이 높았으며, 도덕발달수준이 낮고, SCL-90-R의 적대감척도점수가 높으며 PDQ-R의 반사회적 인격장애에 해당되는 경우가 많았다. 두 집단간 가족환경이나 부모양육태도에는 유의한 차이가 나타나지 않았다. 재범군은 폭력범죄로 구속된 경우가 비재범군에 비해 적었고 첫 범죄시 연령이 어리고 전과가 있는 경우가 많았다. 로지스틱 회귀분석 결과, 재범에 대한 예측요인으로 첫 범죄당시 연령(오즈비=2.91), 반사회적 성격장애(오즈비=2.85), 신체적 학대력(오즈비=2.65)의 세 변인이 포함되었으며, 재범여부에 대한 판별력은 72.8%로 나타났다. 결 론 : 본 연구결과 구속된 청소년들의 재범률이 매우 높다는 사실과 범죄행위에 가담한 연령이 어릴수록, 반사회적 성격장애가 있고 성장과정 중 부모로부터 학대를 받은 경험이 있을수록 반복적인 범죄를 저지를 위험도가 높다는 것을 알 수 있었다. 향후 비행 청소년들의 재범을 예방하기 위해서는 이러한 특성을 가진 고위험군에 대한 조기개입 및 적응을 돕기 위한 프로그램의 개발이 중요할 것으로 사료된다. Objectives : This study was performed to investigate the factors predicting recidivism within 6months after release in arrested juvenile delinquents for proper screening and intervention of high-risk-subjects. Methods : The subjects consisted of 125 arrested male adolescents who were released after legal procedure in prosecutor office and court. The socio-demographic and crime-related characteristics. Were evaluated by police records, and the familial, psychopathology and personality characteristics, and the level of moral development measured by the Conflict Tactics Scale(CTS), Family Environment Scale(FES), Parental Behavioral Inventory, Symptom Checklist-90-Revised(SCL-90-R), Beck Depression Inventory, Beck Anxiety Inventory, Korean form of Moral Developmental Inventory for adolescents, and Personality Disorder Questionnaire-Revised(PDQ-R). Results : The recidivism rate within 6 months after release was 44% of the initial sample, Recidivists were younger and had higher scores on Anger-hostility scale of SCL-90-R and lower principle morality score than nonrecidivists. More recidivists had history of physical abuse and antisocial personality disorder on PDQ-R than nonrecidivists. They also showed the crime-related characteristics of lower percent of violence crime, higher incidence of previous conviction, younger age of the first crime. Among those variables, logistic regression showed that age of first crime, antisocial personality disorder, and history of physical abuse best predicted the recidivism within 6months after release. Conclusion : These results of present study suggest that the recidivism rate of arrested male adolescents is very high, and the age of first crime, antisocial personality disorder and history of physical abuse were key factors predicting recidivism. To prevent repeated crime of delinquent adolescents, the development of programs for those high-risk groups to help rehabilitation and adaptation in community would be essentil.

The Shape Operator of the Tubular Hypersurfaces

Cho, Bong-Sik The Korean Society for History of Mathematics 1998 Journal for history of mathematics Vol.11 No.1

Using Fermi coordinates and the principle curvature on the tubula hypersurfaces, we characterize space of constant sectional curvature by analysing the shape operator on the tubular hypersurfaces.

A Note on the Constant Curvature and Metric

Cho, Bong Sik 圓光大學校 基礎自然科學硏究所 1993 基礎科學硏究誌 Vol.12 No.1

本 論文에서는 等溫座標를 갖는 R^n위의 모든 計量이 定曲率이 되는 必要充分조건을 유도하는데 있다.

A note on the geometric structure of the t-distribution

Bong Sik Cho,Sun Young Jung 한국데이터정보과학회 2010 한국데이터정보과학회지 Vol.21 No.3

The Fisher information matrix plays a significant role in statistical inference in connection with estimation and properties of variance of estimators. In this paper, the parameter space of the t-distribution using its Fisher`s matrix is defined. The α-scalar curvatures to parameter space are calculated.

A Note on the Geometrical Properties of the Normal Distribution

( Bong Sik Cho ) 호남수학회 2007 호남수학학술지 Vol.29 No.1

Geometrical Properties of t-Distribution

( Bong Sik Cho ),( Hoh Yoo Baek ) 호남수학회 2006 호남수학학술지 Vol.28 No.3