PET 共重合體의 結晶化

曺在興,陸燦男 조선대학교 기초과학연구소 1987 自然科學硏究 Vol.10 No.1

Crystallization of PET copolymers with some comonomers were studied by differential scanning calorimetry and densitometry. The results as follows; (1) Crystallinities of PET were increased with increasing the densities of the PET copolymers. (2) Crystallization was delayed with increasing the viscosities of PET copolymers. (3) Crystallization temperature were decreased with increasing the mole percent of copolymers used.

煉炭灰를 利用한 土壤의 改良과 中和에 關한 硏究

曺在興,曺秉旭 朝鮮大學校 工科大學 1974 論文集 Vol.3 No.-

This study is carried out to find out how to neutralize and fertilize the acidified soil of this country by using briquette ash. In order to increase the alkali content in briquette ash, certain amount of shell-lime is added in the process of the manufacture of briquette. After examining the PH variation of the briquette ash and the charge in physical property and PH of the soil to which briquette ash is added, the practicability is considered in view of the calorific value and combustion temperature of the skell-lime added briquette. 1. The result obtained is that the PH of briquette ash is three or four times as high as that of Korean typical soil. 2. The result obtained is that the most favorable ratio of shell-lime in the briquette is 3 percent, considering the heat and combustion temperature when the briquette burns. 3. When briquette ash is added, the available water content increases by 36% (10.7%∼46.7%) and the bulk density of the soil decreases considerably.

외상성 교합으로 인한 어린이의 치주질환

최병재,고동현,김성오,이제호,손흥규 大韓小兒齒科學會 2004 大韓小兒齒科學會誌 Vol.31 No.3

외상성 교합은 교합력의 결과로서 치주조직에 가해지는 손상이다. 주된 증상은 치아의 동요도이고, 통증, 타진에 민감, 열에 민감한 증상이 동반될 수 있으며 교합력에 의해 치아가 이동을 할 수도 있다. 만성으로 진행시 치아의 과도한 교모가 나타나며 방사선학적으로 치근막 공간의 비후, 치조백선의 비후, 치조골의 방사선 투과성, 치근흡수 등이 나타날 수 있다.외상성 교합은 치주질환의 원인과 관련되어 있다. 증가된 치아동요도를 야기하며 외상성 교합 자체는 치은염과 치주낭을 발생시키지 않으나 국소적 치태와 염증이 존재하고 있는 하에서 골소실, 치주낭이 발생할 수 있다. 치은퇴축은 외상성 반월, 맥콜스 팽윤, 스틸만 균열의 형태로 나타난다. 본 증례는 하악 유견치 부위의 치주질환을 주소로 내원한 5세 남아로서 상하악 유견치의 조기 접촉에 의해 하악 좌우측 유견치의 중증도의 동요도, 교합마모, 치은 퇴축, 치조골 파괴의 증상이 나타났기에 보고하는 바이다. Trauma from occlusion(TFO) is injury to the periodontal tissue as a result of occlusal forces. Mobility is a common clinical sign of occlusal trauma. In acute occlusal trauma, this may be accomanied by pain, tenderness to percussion, thermal sensitivity, and pathologic tooth migration. Chronic occlusal trauma may be marked by excessive wear and gingival recession. Radiographic finding include a widened periodontal ligament space, radiolucence and condensation of the alveolar bone, and root resorption. TFO is related to the pathogenesis of periodontal disease. It can cause increased tooth mobility. TFO itself does not initate or aggravate marginal gingivitis or initiate periodontal pockets. Active trauma can accelerate bone loss, pocket formation and gingival recession depending on the presence of local irritants and inflammation. Gingival recession associated with occlusal forces includes traumatic crescent, McCall's festoon and Stillman's cleft. TFO plays a minor role in the pathogenesis of early to moderate periodontitis. A 5-year-old male visited Yonsei University Pedodontics clinic with a chief complaint about gingival recession. Mobility, excessive wear, gingival recession were detected by clinical exam on the both mandibular deciduous canine. On the radiographic view, vertical alveolar bone loss was observed on both mandibular deciduous canine.

Dimethylsulfoxide 용매속에서 Tropaeolin의 Polarography적 환원에 관한 연구

조재흥,윤석진,김두화 조선대학교 기초과학연구소 1986 自然科學硏究 Vol.9 No.1

反陽性子性 溶媒인 dimethylsulfoxide (DMSO)中에서 Tropaeolin에 대하여 직류폴 라로그래피적 거동을조사하였다. 0.05M NaCIO_4의 DMSO溶媒中에서 Tropaeolin은 /電子/段階의 還元過程을 거쳐 hydrazo化合物로 還元된다. 各段階의 還元電流는 擴散支配的 이었으며 一部 反應電流도 包含되었다. *공식은 원문참조 The direct current polarographic behavior of Tropaeolin in dimethyIsulfoxide as an aprotic solvent have been investigated. The reduction of Tropaeolin in 0.06M sodium perchlorate solution proceeds along two one-electron steps to give the corresp ending compound containing hydrazo group, each reduction wave was considerably diffusion controlled and irreversible. *formula see the original

Silicone die를 이용한 교합면우식증의 composite resin inlay 치료증례

최병재,손흥규,김성오 大韓小兒齒科學會 1992 大韓小兒齒科學會誌 Vol.19 No.2

In the past, the goals of dental treatment were to relieve pain and to intercept disease processing. Nowadays, however, food, clothing and housing have been promoted and dental considerations for restoring esthetic and masticatory function have become increased. Therefore several esthetic restoration techniques for posterior teeth were developed : direct resin filling, porcelain inlay/onlay and composite resin inlay/onlay. The purposes of this article are to review the problems and the improvements of direct resin filling techniques on posterior teeth and to report a case of composite resin inlay technique with silicone materials on posterior tooth. The problems of conventional direct resin filling techniques are severe occlusal wear, microleakage from polymerization shrinkage, recurrent caries, poor proximal contact, isthmus fracture, postoperative sensitivity, poor radiopacity, ect. In order to solve these problems, complete polymerization on comnposite resin is needed. Therefore resin inlay technique is developed with additional light, heat and pressure curing. Although physical properties(wear resistence, tensile strength, etc.) have been improved with composite resin inlay technique, the procedures are complicated and time consuming. On this report, we improved the fabrication of composite resin inlay with silicone rubber base materials.

미성숙 영구치의 치근파절에 관한 증례보고

최병재,손흥규,김수연,최형준 大韓小兒齒科學會 1997 大韓小兒齒科學會誌 Vol.24 No.3

During the eruption of permanent teeth, Traumatic root fractures in young permanent incisors are rare. They occur most commonly in the maxillary central incisors of male patient and are frequently seen in the coronal third of the root. Permanent incisors are very important in terms of esthetics as well as of function, and so conservative treatment is advisable. It is important to maintain vitality of pulp to achieve better result. Location of the fracture line determines the Prognosis. No clinical change were seen in this three case. A case of central incisor with apparent healing of a root fracture without any tratment is presented in this paper. Long term clinical observation is required periodically.

작업장 특성에 따른 톨루엔 노출 근로자의 마뇨산 배출 특성

박흥재,김형준,정성욱,이병호 한국환경과학회 2005 한국환경과학회지 Vol.14 No.2

This study was carried out to investigate the correlation between toluene in air and hippuric acid in human urine, which is based in the results of the health check-in and measure of working environment, was investigated for five years. Toluene in air and hippuric acid in urine were checked 116 workers who exposed to toluene in five type of industry. The Mean concentration of toluene in air by type of industry and every year and sex distinction, had positive correlation.(p<0.01) The Mean concentration of hippuric acid in urine by type of industry, every year, sex distinction, disparity of age and term of duty had positive correlation.(p<0.01)

Nd: YAG 레이저 조사가 Clacium Fluoride 형성 및 치아 내산성에 미치는 영향

최병재,김성오,손흥규,이제호,박광균 大韓小兒齒科學會 1999 大韓小兒齒科學會誌 Vol.26 No.2

불소도포시 주로 형성되는 calcium fluoride는 구강내 환경에서 pH에 의해 조절되는 불소의 저장고 역할을 하여 치아우식 예방에 있어서 중요한 역할을 하는 것으로 알려져 있다. 따라서 불소도포의 우식예방 효과는 calcium fluoride를 얼마나 많이 형성시켜 오래 지속시키는 가에 달려있다. 이에 치아 내산성 증가에 효과 있다고 알려진 Nd:YAG 레이저 조사가 calcium fluoride형성 및 치아 내산성에 미치는 영향에 대해 알아보기 위해서 실험을 시행하였다. 소의 영구전치에서 276개의 시편을 제작하여 아무런 처치를 하지 않은 군을 대조군으로 하고 1.23% acidulated phosphate fluoride (APF) 5분, 30분 도포 및 Nd:YAG 레이저 조사에너지 밀도 20J/㎠,40J/㎠의 조건에 따라 불소 도포군, 레이저 조사군, 불소 도포후 레이저 조사군, 레이저 조사후 불소 도포군으로 분류하였다. 불소도포를 시행한 경우 이를 다시 KOH 처리 여부에 따라 나누어 23개의 실험조건을 만들었다. 각 실험조건에 12개의 시편을 배정하고 이중 10개의 시편은 불소 및 무기인 측정에, 나머지 2개의 시편은 표면 관찰에 사용하였다. KOH 비처지군에서 0.1N HCIO4로 enamel biopsy를 시행하여 탈회 법랑질의 불소농도 및 탈회깊이를 측정하였으며, KOH 처치군에서는 1 M KOH로 24시간 처리하여 calcium fluoride를 정량 후 enamel biopsy를 시행하였다. 실험결과 얻어진 자료 및 주사 전자현미경 관찰 소견을 비교하여 다음의 결과를 얻었다. 1. KOH 비처치군에서 탈회된 법랑질의 불소농도는 레이저조사 후 불소도포시 레이저 에너지 밀도 증가에 따라 증가되는 경향을 보였다. 2. KOH 비처치군에서 법랑질 탈회깊이는 불소를 5분 도포후 레이저 20J/㎠를 조사한 경우를 제외하고는 레이저와 불소를 병행하여 처치시 각각을 단독으로 치치시보다 탈회깊이가 작았다 (p<0.05). 3. Calcium fluoride의 양은 레이저의 조사에 의해 유의 있게 증가하지 않았다 (p>0.05). 4. Calcium fluoride 입자는 불소만 도포한 경우에 비해 레이저 조사후 불소도포시 입자크기가 증가되었으며, 불소도포후 레이저 조사시 입자크기의 증가와 함께 일부 융합된 양상을 보였다. 5. KOH 처치군에서 법랑질의 불소농도는 불소를 30분 도포후 레이저를 조사한 경우를 제외하고는 대조군의 불소농도와 유의한 차이가 없었다(p>0.05). 6.KOH 처치군에서 불소와 레이저를 병행한 경우, 불소만 도포한 경우보다 탈횐된 법랑질의 깊이가 작았다 (p<0.05). 7. KOH 비처치군에서 탈회된 법랑질의 불소농도와 탈회깊이의 상관관계 (Spearman correlation coefficient: -0.6281)는 KOH 처치군 (Spearman correlation coefficient: -0.3792)에 비해 높은 음의 상관 관계를 보였고, 동일한 조건으로 불소도포 및 레이저 조사를 시행한 경우에 있어서 KOH 처리 여부에 따른 탈회법랑질 깊이의 유의차가 있는 경우 calcium fluoride의 형성량이 많았다. 이상의 실험결과로 미루어 보아 레이저 조사가 calcium fluoride의 형성량에 영향을 미치지 않았으나 레이저 조사의 영향으로 calcium fluoride의 용해가 감소하는 것으로 판단된다. 또한 불소도포 및 레이저 조사의 병행은 각각을 단독으로 처치한 경우에 비하여 치아 내산성 증가면에서 유리하므로 임상에서 불소도포주기 연장과 같은 유용한 결과를 얻을 수 있을 것으로 생각된다. Calcium fluoride. created by topical fluoride application, is the reservoir for fluoride ion regulated by pH in the oral environment. Therefore, the amount and the maintenance of calcium fluoride have an important role in preventing dental caries. The aim of this study is to evaluate the effect of Nd:YAG laser irradiaiton on the generation of calcium fluoride and the acid resistance of tooth enamel. The bovine anterior permanent teeth were prepared (n=276), and divided into following groups: no treatment(control), fluoride application alone, laser irradiation alone, laser irradiation after fluoride application, and fluoride application after laser irradiation. And each group was subdivided based on the application time of 1.23% acidulated phosphate fluoride (APF) (5 min and 30 min) and the irradiation energy of Nd:YAG laser (20J/㎠ and 40J/㎠). In case of fluoride application, each group was divided according to KOH treatment. Twenty three treatment conditions were made for this experiment and twelve specimens were assigned to each treatment condition. In each treatment condidtion, ten specimens were used for chemical analysis and two specimens were observed under SEM. In groups without treating KOH, fluoride content and the depth of enamel dissolved were measured using enamel biopsy technique. In groups with treating KOH, the amount of calcium fluoride was measured by the treatment with 1 M KOH for 24 hours and enamel biopsy was performed after KOH treatment. The results were analyzed by the fluoride content and the depth of enamel dissolved by enamel biopsy, amount and thickness of calcium fluoride, and the surface structures of enamel. The results are as follows: 1. In groups without treating KOH, the fluoride content of removed enamel showed a positive relationship with the energy density of laser when the laser irradiated before fluoride application. 2. In groups without treating KOH, the depth of enamel dissolved decreased more with the combined laser and fluoride treatment than with laser or fluoride treatment, except for the case of 20J/㎠ laser irradiation after 5 minute fluoride application (p<0.05). 3. The amount of calcium fluoride did not increased by laser treatment with no statistical significance(p>0.05). 4. The particle size of calcium fluoride increased in case of fluoride treatment after laser irradiation, compared with fluoride application alone. In case of laser treatment after fluoride application, the particle size of calcium fluoride increased and some of the particles fused as well. 5. There were no significant differences in the fluoride content of dissolved enamel between groups without treating KOH and control group, except for the case of laser irradiation after treatment of APF for 30 minutes (p>0.05). 6. In groups with treating KOH, depth of removed enamel in the groups of combined treatment with laser and fluoride was shallower than that in fluoride application groups (p<0.05). 7. In groups without treating KOH, the relationship between fluoride content and the depth of enamel dissolved showed more negative (Spearman correlation coefficient: -0.6281)than in groups with treating KOH (Spearman correlation coefficient: -0.3792). The greater amount of calcium fluoride could be found in case where there was a significant differences of the depth of enamel dissolved between groups with and without treating KOH. From these results, it can be concluded that laser seems to be a little effects on the amount of calcium fluoride formation, but has some effect on the lowering the solubility of calicium fluoride. As the combined treatment of laser and fluoride application showed more effective acid-resistant property, more extended recall period for fluoride application can be achieved with this combined treatment in the clinic.

치아의 견인을 위한 버튼 접착시 오염이 인장강도에 미치는 영향

최병재,김성오,이제호,손흥규 大韓小兒齒科學會 1998 大韓小兒齒科學會誌 Vol.25 No.2

We already know that it is very difficult to obtain an 'isolated field' for direct bonding during the surgical exposure of unerupted teeth. The aim of this in-vitro study is to simulate the clinical situation of forced eruption and to evaluate the tensile strengths of preligatured button with several types of contamination which can happen during the surgical exposure of unerupted teeth. Four orthodontic direct bonding systems were used. (Ortho-One, Rely-a-Bond, Ortho-Two, PhaseⅡ) Each material was divided into four groups(n=20) : Group 1. (Control, no contamination), Group 2. (Rinse etching agent with saline instead of water), Group 3. (Blood contamination of etched surface for 30 seconds), Group 4. (Blood contamination of primed surface for 30 seconds) 320 bovine anterior permanent teeth were divided into the above mentioned 16 groups. Enamel surface was flattened and ground under water coolant. Pre-ligatured buttons were prepared to the same form. (Cut 0.25 ligature wire 10 cm in length. Twist the ligature wire 30 times clockwise. Mark the wire 15mm and 35mm points from button. Make a loop sticking two points together and twist the loop 6 times counterclockwise.) The bonded specimens were stored at 37℃ saline solution for 3 days. then the tensile strength of each sample was measured with Instron universal testing machine, crosshead speed of 0.5mm/min. the following results were obtained : 1. As compared to control groups (Group 1) of each material, Rely-a-Bond had a significantly lower mean tensile strengths than other material. (p<0.01) 2. In Group 2. of Ortho-One and Rely-a-Bond, the mean tensile strengths decreased about 7.7% and 11.1%, respectively with statistical significances. (p<0.05) 3. In Group 2. of Ortho-Two and PhaseⅡ, the mean tensile strengths did not decrease. 4. In Group 3. of Ortho-One, Rely-a-Bond, Ortho-Two, and PhaseⅡ, the mean tensile strengths decreased about 60.8%, 56.1%, 60.2%, and 46.0%, respectively with statistical significances. (p<0.01) 5. In Group 4. of Ortho-One and Rely-a-Bond, the mean tensile strengths did not decrease. 6. In Group 4. of Ortho-Two and PhaseⅡ, the mean tensile strengths were decreased about 20.95% and 22.28%, respectively with statistical significances. (p<0.01) There were formations of a hump shaped mass from bonding resin under blood contamination which disturbed direct bonding procedure. According to Reynolds, the proper bond strength for clinical manipulation should be at least 45N or about 4.5Kg.F. According to these results, it can be concluded that Ortho-One could be used during surgical exposure of unerupted teeth. In any case, blood contamination of the etched surface should be avoided, but the blood contamination of primed surface of Ortho-One may not decrease bond strength. Just 'blowing-out' is enough to remove blood from primed surface of Ortho-One. You can verify the clean surface of the primer of Ortho-One after blowing out the blood contamination.

Topology에서 강연결 집합과 약불연결 집합에 대한 연구

김재흥 圓光大學校大學院 1982 學位論叢 Vol.8-2 No.-

강 연결집합과 약 불연결집합윤 [1]에 소개된 바 있다. 본 논문의 목척은 강 연결집합과 약 불연결집합의 성질을 조사하는데 목적이 있다. 주 정리는 다음과 같다. [정리 1] A가 강 연결 집합이연 A는 연결집합이다. [정리 2] A가 약 불연결집합이 되기 위한 필요충분조건은 A안에 공집합이 아닌 서로소인 두 폐 집합 E와 F가 존재하는 것이다. [정리 3] 위상공간 X가 T₁-공간이 되기 위한 필요충분조건은 X가 천체적A로 약 불연결 집합이 되는 것이다. [정리 4] {(X_(α)|T_(α)α∈Δ} 가 공집합이 아닌 공간들의 공집 합이 아닌 족이라 하고 (X,T) 가 적위상이라면 (X,T)가 강연결집합이 되기 위한 필요충분조건은 각 α∈Δ에 대하여 (X_(α),T_(α))가 강 연결집합이 되는 것이다. [정리 5] A={A}를 X에서 강 연결집합의 chain이라연 U{A|A∈A}도 강 연결집합이다.