치주적 손상을 유발하는 latex-elastic ring의 부적절한 사용에 대한 증례보고

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

This paper presents improper use of latex-elastic ring in movement of teeth and its consequence. Simple orthodontic movement of teeth including closure of diastema may be achieved by the use of simple method with fixed or removable appliance associated with latex-elactic ring. But, if it is used alone, it acts as a local irritant and then produces localized periodontitis. In case of localized periodontitis resulting from latex-elastic ring, diagnosis is difficult because the patient is usually unaward of the presence of the rings on the roots of the involved teeth and because the ring is not probed and is radiolucent and therefore not discernible radiographically and clinically. Occasionally, surgery is requred for the detection. This case emphasizes the necessity that the use of latex-elastic ring in closing diastema should be accompanied with removable or fixed appliance as well as close professional supervision. Its use without adequate provision for stabilization or retention on the crowns of teeth results in destruction of periodontal support and the teeth may be lost.

급속응고된 Al-Zr 합금의 시효현상에 미치는 Si첨가의 영향

최상욱,박홍일,김명호 울산대학교 1987 연구논문집 Vol.18 No.2

본 연구에서는 급속응고된 Al-Zr 합금의 과포화 고용도에 미치는 제3첨가 원소 Si의 영향 및 급속응고된 Al-Zr-Si 합금계의 시효특성에 관하여 실험적으로 조사하였다. Twin-roller 장치에 의하여 급속응고시킨 시편의 응고속도는 10?? K/s 정도였으며, 이때 Al기지내에 Zr은 약 1 wt.% 정도만이 과포화 고용되었다. 그러나 Si의 첨가량이 증가됨에 따라 Zr의 과포화 고용도는 증대되어 Si의 첨가량이 1 wt.% 일때 Zr은 1.7 wt.% 정도 Al기지내에 완전 과포화 고용되었다. 그리고 Si의 첨가량이 증가됨에 따라 Al-Zr 합금의 미소경도는 증대되었다. Al -1.7wt.%Zr -1.0wt.%Si 합금을 시효처리하면 Si이 우선 미세한 구상석출물을 형성하며 초기 시효경화를 일으킨 후, 잇따라 Zr의 준안정 석출물이 불연속 석출되어 성장하며 최대 시효경화를 나타냄을 알 수 있었다. An experimental investigation has been made about the effects of the third alloying element silicon on the sold solubility of zirconium in the aluminium, and on the ageing phenomena of Al-Zr-Si alloys. Rapidly solidified specimens were prepared by a twin-roller quenching apparatus in the form of long, thin ribbon, whose cooling rate was estimated to be about 10?? K/s. Under such a cooling rate, the maximum solubility of zirconium in solid aluminum was extended to about 1.0wt.%. However, it was extended up to 1.7wt.% by addition of 1.0wt.% silicon. With the increase of silicon content, the microhardness of Al-Zr alloys were increased as well. Ageing of supersaturated Al-1.7wt.% Zr-1.0wt.% Si solid solution appeared to occur in three sequential stages; Ⅰ. precipitation of silicon as fine spherical particles which harden the alloys, followed by Ⅱ. discontinuous precipitation of metastable zirconium phases which produce remarkable age hardening of the alloys, and finally Ⅲ. formation of coarse equilibrium zirconium phases.

燃料電池用 直流 電力 變換機 開發

崔璋浩,成世眞,李興浩 忠南大學校 産業技術硏究所 1991 산업기술연구논문집 Vol.6 No.2

This paper deals with a Power Conversion System for Fuel Cell. The system consists of Chopper, Inverter and Control Unit. Chopper boosts the output voltage of Fuel Cell and controls reactive power. Inverter converts DC into Ac and controls active power. Controller is realized by the Software Method using a 8031AH one-chip Microprocessor. Simulated results are consistent with experimental results.

수용액에서 AO-SDS계의 회합 생성에 관한 연구

崔虎燮,金興斗 群山大學校基礎科學硏究所 1994 基礎科學硏究 Vol.9 No.-

낮은 온도에서 유기색소와 계면활성제 계의 흡수거동을 계산하기 위해 간단한 모델을 사용해 보았다. 실험에서 얻어진 값에 3개의 파라미터가 포함되어 있는 결과식을 적용함으로써 이온쌍형성 (Ko), 화합체에 계면활성제 분자 첨가의 경우(Ks), 그리고 색소화합반응 Kd에 대한 평형상수들을 계산하였으며 이 값들을 이용하여 자유에너지를 계산하였다. Ko와 Ks의 값들은 소수성에 원인이 있는 정전기적 상호작용에서 기대했던 것들보다 컸었고, kd값들은 정전기적 반발력의 차폐효과로 간주할 수 있는 순수한 수용액에서의 알려진 회합값보다 약 10∼20배 정도 높았다. At low concentration a simplified model of organic dye-surfactant system has been used to evaluate. By applying the resultant three parameter equation to the experimental data, values for the equilibrium constants for the ion-pair formation (Ko) surfactant molecule addition to aggregates(Ks), and dye aggregation reactions?? could be calculated and changes of free energy have obtained from its values. Ko and Ks values were larger than those expected electrostatic interaction indicating a hydrophobic contribution and the ?? values were about 10∼20 times higher than those found for association in pure aqueous solutions which can be ascribed to the screening effect of the electrostatic repulsion.

초음파에 의한 생체조직내 비선형 전파특성에 관한 연구

최흥호 인제대학교 1996 仁濟論叢 Vol.12 No.2

The parameter, B/A, quantifies nonlinearity of the pressure-density relationship of propagation medium. The purpose of this study is to investigate the characteristics of ultrasonic nonlinear propagation in biological tissue using this ultrasonic nonlinear parameter, B/A, obtained by the second harmonic amplitude method. In order to examin this purpose, a series of computer simulation and fundamental experiments in distilled water are carried out. * Key words : Nonlinear parameter B/A, 2nd harmonic amplitude method, ultrasound

상악 유측절치 부위의 유치 과잉치에 관한 증례보고

최병재,한효정,이제호,김성오,손흥규 大韓小兒齒科學會 2006 大韓小兒齒科學會誌 Vol.33 No.1

과잉치란 치배 형성기 이상으로 유치열기와 영구치열기에 정상보다 많이 발생하게 된 치아를 말한다. 유치 과잉치의 빈도는 0.03~1.9%로 상악 유측절치 부위에 호발하고 대부분은 정상 치아 형태로 맹출하며 정상 시기에 탈락하므로 보호자들이 인식하지 못하는 경우가 많다. 과잉치의 발생에 대해서는 현재 치판의 과활성으로 인해 제 3의 치배가 발생한다는 가설이 널리 받아들여지고 있고 유치과잉치가 발생할 경우 영구치열기에는 정상 또는 비정상적인 형태의 계승 과잉치가 존대한다고 보고된 바 있다. 유치 과잉치의 약 75%는 정상적으로 맹출하고 탈락하기 때문에 특별한 처치는 필요하지 않지만 계승 영구치 맹출에 영향을 주는지를 관찰하기 위하여 정기적인 구강 및 방선학적 검사가 필요하다. 본 두 증례의 경우 정상 치아 형태의 유치 과잉치가 유전치부 발육 공간을 이용하여 상악 유측절치 부위에 맹출하였고 방사선 사진 검사 결과 유치 과잉치 하방에 매복된 계승 과잉치가 관찰되었으므로 이에 보고하는 바이다. Most supernumerary primary teeth erupt in the primary lateral incisor region and are reported to occur in 0.03 to 1.9% in the primary dentition. Most parents fail to recognize them because of their normal shape, eruption and exfoliation. Several theories have been proposed for the etiology of hyperdontia and the dental lamina hyperactivity theory is most widely accepted. When a supernumerary primary tooth develops. it is reported that there also exists a supplemental or rudimentary form of a succedaneous supernumerary tooth. Supernumerary primary teeth do not need specific treatment as 75% of them erupt and exfoliate normally. Only periodic radiographic exams are necessary to find out whether there is any problem with the eruption of the succedaneous tooth. In the following two cases, a supplemental supernumerary primary tooth with a loss of the anterior developmental space was observed at the maxillary lateral incisor region. Radiographic examination revealed an impacted succedaneous supernumerary tooth at the palatal side of the supernumerary primary tooth.

복합 치아종에 관한 증례보고

최형준,최병재,손흥규,양호정 大韓小兒齒科學會 1995 大韓小兒齒科學會誌 Vol.22 No.2

The odontoma is relatively a common odontogenic tumor. It has come to mean as a growth in which both the epithelial and the mesenchymal cell exhibit complete differentiation, with the result that functional ameloblast and odontoblast form enamel and dentin. The etiology of it is unknown, but it has been suggested that local trauma or infection may lead to the production of such a lesion. Odontma is divided into 2 types. One is compound odontoma that is at least superficial anatomic simiarity to normal teeth, and the other is complex odontoma, that calcified dental tissues are simply an irregular mass bearing no morphologic similarity even to rudimentary teeth. Somtimes this malformation is not easily identified because its lacking of calcification. So, if permanant tooth is delayed to erupt, one should take a careful look the radiographic film to find that whether the cause of it is odontoma or not. In this case report, 3 patients with odontoma who visited Dept. of Pediatric Dentistry in Yonsei Dental College, were treated by means of surgical removal. The obtained results were as follows: 1. The odontoma is usually related to impacted tooth, and it is occurred neighboring to the crown of impacted tooth that have normally developed. So, in the case of missing tooth and delayed eruption, its presence should be investigated. 2. The odontoma can be seen vaguely radiographically, so, it is difficulty to make diagnosis. 3. The treatment of odontoma is a surgical removal. And, if it is completely removed, its occurrence is rare. 4. In the case of impacted tooth being associated with compound odontoma, continuous management is necessary for the eruption of impacted tooth after the surgical extraction of odontoma. 5. It resembles the ameloblastic odontoma radigraphically, and if it is the case, the treatment may vary, so the confirmation through histologic examination after removal of mass is necessary.

裁植距離가 輸出用 가지(Solanum melongena. L)의 生育 및 收量에 미치는 影響

최성관,이재필,진동호,오주성,박흥식,정순재 동아대학교 농업생명과학연구소 2001 農業生命資援硏究 Vol.10 No.1

This study was carried out to investigate effect of the planting distance of Eggplant(Solanum melongena. L). These grafting seeding "Torobambica", rootstock "Jang Ja" and "Chuk Yang" were tested to investigate the differences between the growth of eggplants and the numbers of eggplants which can be influenced by the planting distance such as 100×50cm, 100×60cm and 100×70cm. The results are summarized as follows: 1.The plant height, leaf length, leaf, width, leaf area and the number were good for the growth change of each cultivar from planting distance such as 100×70cm. 2.The grafting seedlings "Chuk YanglTorobambica" grew and developed better than "Jang Ja" and "Jang Ja/Torobambica" 3.Effects of scion on the rootstock for planting distance "Chuk Yang" grew and developed better than "Jang Ja"

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.

수용액에서 유기 색소와 Sodium Dodecyl Sulfate와의 흡수 및 형광분광학적 연구

崔虎燮,金興斗 群山大學校基礎科學硏究所 1995 基礎科學硏究 Vol.10 No.-

The interactions of the organic dye stuffs, thionine(TH), methylene blue(MB) and toluidine blue (TB) to anionic surfactant, sodium dodecyl sulfate(SDS) are studied using absorbance and fluorescence spectroscopies. We have been investigated the absorbance variation and the relations between the concentration of SDS dependence on temperature the fluorescence intensity as the concentration of the anionic surfactant is increased. We could be calculated the equilibrium constants(Kd,Ks) by applying the model, and we have seen that they were about 10∼30 times higher than those found for association in pure aqueous organic dye stuffs. By using the equilibrium constants the changes of free energy(­ΔG) can also obtained.