• 문화기술의 융합
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• 제6권3호
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• pp.393-399
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• 2020

본 연구에서는 터널 굴진 시 조우한 석회공동의 지하수 유출에 따른 지반침하 거동을 수치해석을 바탕으로 정량화하고 영향정도를 분석하였다. 현장에서 조사된 지하수위 및 지표면 침하량 등을 토대로 수치해석 기법을 적용하여 지질취약대 터널통과에 따른 지반침하거동의 특성을 분석하였다. 지하수 침투-응력연계해석결과, 수치해석결과는 실제 지반침하거동을 잘 반영하는 것으로 분석되었다. 연구결과, 지질취약대인 석회암 공동구간의 터널 굴착에 따른 지반 침하는 급격한 지하수위 하강이 주요 원인인 것으로 분석되었다. 수치해석결과, 지하수위 강하에 의한 토사층 체적감소로 인해 지하수 유출된 이후의 장기적인 아스팔트 지표면 장기 누적침하량은 76~118mm인 것으로 분석되었으며 침하량은 토사층 깊이가 깊을수록 증가하는 양상을 나타냈다.

• 대한치과기공학회지
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• 제25권1호
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• pp.9-20
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• 2003

Using a nickel-chrome casting alloy called 'Rexillium V' which is also available as base metal alloy for dental ceramic crown, 4 types of mixtures(A, B, C, D) with old and new metal were prepared for cyclic casting. The results of cyclic casting can be outlined as follows: 1. For Vickers hardness after casting, specimen A and D tended to have lower hardness in the course of cyclic casting, while specimen B and C tended to higher hardness. 2. The results of X-ray diffraction analysis showed that major crystal phase contained nickelchrome compounds and carbide. 3. The observation results of SEM photographs after cyclic casting show that there was a significant tendency to have similar structures among experimental groups. 4. The results of EDX analysis after cyclic casting showed that there were little differences in chemical composition between parent metal and base metal alloy. Although industrial nickel-chrome cast alloy did not show any significant change in material properties even through cyclic casting over several times, it is recommended that more there be more in-depth studies on how to detect any potential corrosion, discoloration and toxication of dental ceramic crown implanted in patient's oral cavity.

• Asian Pacific Journal of Cancer Prevention
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• 제16권8호
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• pp.3499-3503
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• 2015

Background: Cancer has become an epidemic disease. Nearly ten million new cancer cases are diagnosed annually in the world and out of these about half are from the developing world. To appropriately plan for treatment, management and prevention of the disease, it becomes necessary to study the trends about morbidity caused by cancers. Materials and Methods: Data for patients diagnosed with any form of gastrointestinal (GI) cancers was extracted from records maintained in the outpatient department registers of the Oncology Department of Government Medical College and Hospital in Chandigarh from 1999 to 2012. Trends were analysed for different categories of GI cancers for the period of 12 years. Results: In present study GI cancers accounted for 23 % of all registered cases (n-9603) of carcinomas. Males predominated for all GI cancers except in the gall bladder. Gastrointestinal cancers as a proportion of total cancers increased from 21% in 1999 to 25.9% in 2012 with a significant increasing trend in our series (${\chi}^2$ for linear trend=9.36, p<0.003). Cancers of the tonsil, oral cavity and pharynx taken together showed an increasing trend over the years (${\chi}^2$ for trend=55.2, p<0.001) whereas cancers of the lower GI (${\chi}^2=19.6$, p<0.0001) and gall bladder (${\chi}^2=19.5$, p<0.0001) showed a declining trend in our series. Conclusions: GI cancers form a significant proportion of all cancers reporting to our data. In depth studies to ascertain the reasons for the changing trends are required to design intervention programs. Further information is necessary from cancer registries and from the hospital records of oncology departments.

• Restorative Dentistry and Endodontics
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• 제20권1호
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• pp.362-371
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• 1995

The purpose of this study was to evaluate the shear bond strength between composite resin and glass ionomer cement according to surface treatment methods of glass ionomer cement. Sixty round acrylic cylinders were fabricated. And then, a round undercut cavity(8 mm diameter, 2.5mm depth) was prepared in the center of the every acrylic cylinder. After all cavities were restored by using light-cured glass ionomer cement. A total of sixty acrylic cylinders restored with glass ionomer cement were divided into 4 groups according to surface treatment methods of glass ionomer cement. The surface treatment of each group were as follows : control group : no treatment Group 1 : acid etching Group 2 : sandblasting Group 3 : air-podwer abrasive polishing The composite resin was bonded to glass ionomer cement of each specimens. And the shear bond strength was tested with a universal testing machine at a cross-head speed of 1mm/min and 500kg in full scale. The results were as follows : 1. The sandblasting group(group 2) had the highest shear bond strength with $272.50{\pm}24.96\;kg/cm_2$ and the acid etching group(group 1) had the lowest shear bond strength with $192.89{\pm}29.32kg/cm_2$. 2. The no treated group(control group) had higher shear bond strength than acid etching group(group 1) (p<0.05). 3. The sandblasting group(group 2), air-powder abrasive polishing group(group 3) and no treated group(control group) had higher shear bond strength than the acid etching group(group 1) (p<0.05). 4. The sandblasting group(group 2) and air-powder abrasive polishing group(group 3) had higher shear bond strength than the no treatment group(control group), but there was not significant(p>0.05).

• 센서학회지
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• 제3권3호
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• pp.45-53
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• 1994

실리콘의 직접 접합 방법과 2단계 전기화학적 식 정지 방법을 이용하여 새로운 구조의 실리콘 다이아프램을 제조하였다. 이러한 다이아프램 구조를 기계량 센서에 이용하면 공동의 깊이와 다이아프램의 두께를 보다 정교하게 조절할 수 있다. 또한, 접합 계면에서 발생하는 응력이 다이아프램의 표면으로 전달되는 것을 피할 수 있다. 최종적으로, 제조된 다이아프램을 이용하여 암저항형 실리콘 압력 센서를 제작하였고 압력 단위의 표시가 가능한 디지탈 압력 측정기를 구현하였다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제39권6호
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• pp.292-296
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• 2013

Verruciform xanthoma (VX) is a rare, benign lesion that presents in the oral cavity, skin, or genital organs as a verrucous, papillomatous, or flat papule with varying colors. VX has indistinct clinical features, making histopathological examination necessary for a definitive diagnosis. Histologically, VX is characterized by parakeratosis, rete ridges with uniform depth, and an accumulation of the foam cells, which are also known as the "xanthoma cells". These foam cells test positive for antibodies, such as CD-68 and vimentin; it is thought that VX foam cells are derived from the monocyte-macrophage lineage, and that VX's pathogenic mechanism is partly related to an immune mechanism. Nevertheless, the pathogenesis of VX remains unclear. VX can be treated by surgical excision; other medical, chemical, and radiological treatments are not required postoperatively. Recurrence and malignant transformation of VX are rare. Two patients, each with a mass of unknown origin on the palatal gingiva, were presented at our clinic. Excisional biopsies of the masses were performed for a histological diagnosis after clinical and radiological examinations. Histological examination confirmed a diagnosis of VX in both cases.

• Journal of Periodontal and Implant Science
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• 제36권4호
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• pp.829-837
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• 2006

Halitosis, defined as an unpleasant oral odor, is a commonly experienced condition with a variety of etiological factors and may cause a significant social or psychological handicap to those suffering from it, In most cases, halitosis originates within the oral cavity itself and patients with periodontal disease often suffer from oral malodor, The most common cause of this disease is related to microbiota which reside on the tongue and in the periodontal pocket, This study was undertaken to examine the effect of full mouth disinfection including tongue scraping on oral malodor in a group of patients with chronic periodontitis, The relationship between halitosis and oral health status was also investigated, The volatile sulfur compounds (VSC) scores were significantly correlated with Plaque Index, Bleeding Index, pocket depth, and tongue coating score, The organoleptic ratings were significantly associated with Plaque Index, Bleeding Index. and tongue coating score, The VSC scores and organoleptic ratings correlated strongly with each other. Full mouth disinfection resulted in a significant reduction in the VSC scores. organoleptic ratings, and self-perception of malodor up to 12 weeks, This study indicates that in patients with chronic periodontitis. a full mouth disinfection including tongue scraping has a significant effect in the treatment of oral malodor.

• 대한조선학회논문집
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• 제39권4호
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• pp.42-53
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• 2002

본 논문에서는 황해의 자연 환경과 물류환경에 대한 조사를 바탕으로, 황해권의 해상수송시스템에 적합한 황해형 고속 여객선에 대하여 선형설계를 수행하였으며, 그에 대한 수치계산과 실험을 통하여 저항 성능을 파악하고자 하였다. 황해형 고속 여객선이 인천국제공항의 부족한 육상교통수송수단의 대안으로서 활용되는 것이 적합하다고 판단되었으며, 인천국제공항으로의 해상운송대책을 제시하고자 하였다. 이를 위하여, 계획항로에 대한 경제성의 평가를 수행하였으며, 황해형 고속 여객선의 선형으로는 쌍동선에 대하여 연구하였다. 설계는 기존 고속선 들의 주요제원 및 항로와 수심, 황해권 물류환경 등의 설계 제조건들을 고려하여 수행되었으며, 공기 공동에 의한 저항감소 효과도 검토되었다. 실험에 앞서 수치계산을 수행하여 설계선형의 저항성능을 검토하였으며, 계산 및 실험은 심해조건 뿐만 아니라 운항항로의 얕은 수심을 고려하여 천수조건에 대하여도 수행되었다. 이와 같은 일련의 선형설계와 수치계산 및 실험으로부터 저항성능을 고려한 황해형 고속선형의 설계능력을 확보하였으며, 앞으로의 황해권 해상수송시스템 구축을 위한 활용가능성을 검토하였다.

• Journal of Periodontal and Implant Science
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• 제30권1호
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• pp.203-212
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• 2000

Putrefactive activity within the oral cavity is the principal cause of halitosis. The most common intraoral sites of oral malodor production are tongue, interdental and subgingival areas. The other foci may include faulty restorations, sites of food impaction and abscesses. Periodontal disease frequently involves pathological oral malodor, which is caused mainly by volatile sulfur compounds(VSC), such as hydrogen sulfide, methyl mercaptan, and dimethyl sulfide. The purpose of this study is to evaluate the association between oral malodor and periodontal status. Volatile sulfur compounds in mouth air were estimated by portable sulfide monitor($Halimeter^{TM}$). The results were as follows : 1. The levels of volatile sulfur compounds were significantly greater in a periodontitis group than in a control group(P<0.01). The amounts of VSC in mouth air from patients with periodontal involvement were four times greater than those of the control group. 2. The significant positive correlation was found between VSC concentrations and the number of pocket depth above 4mm(P<0.01), but correlation between VSC concentrations and plaque score was not statistically significant(P>0.05). 3. In the periodontitis group, VSC concentrations of pre-treatment significantly decreased after scaling and root planing(P<0.01). 4. No statistically significant correlation was found between VSC concentrations and sex / age in the periodontitis group. The above results indicate that periodontal disease may play a role as an important factor of oral malodor and deep periodontal pockets are a source of volatile sulfur compounds.

• Restorative Dentistry and Endodontics
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• 제17권1호
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• pp.95-103
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• 1992

The purpose of this study was to evaluate the effect of the dentin pretreatment on the marginal leakage of a glassionomer cement. 1n this study, 60 molars with sound and healthy crown portion were used. The dentin surface of these teeth were exposed and polished with 600 grit silicon carbide paper. Square - shaped cavities were prepared on the flattened dentin surfaces and these were divided into 4 groups according to the dentin pretreatment procedures. Group I : Dentin pretreatment with distilled water as a control group. Group II : Dentin pretreatment with 5% sodium hypochlorite solution. Group III : Dentin pretreatment with Ketac conditioner. Group IV : Dentin pretreatment with 40% polyacrylic acid. The degrees of dye penetration in the cavity walls were assessed using a stereoscope at ${\times}40$ magnification according to the maximum dye penetration. The results were analyzed by using Mann - Whitney U test. The results were as follows : 1. All groups showed varying depth of dye penetration. 2. Distilled water group showed the most severe marginal leakage when compared with the other groups(P<0.05). 3. 40% polyacrylic acid group showed the least amount of marginal leakage compared with the other groups (P<0.05). 4. There were significant differences between Goup I(distilled water) and Group IV (40% polyacrylic acid)(P<0.05), but there were no significant differences among Group I(distilled water), Group II(sodium hypochlorite), Group III(Ketac conditioner) (P>0.05).