• 한국재료학회지
• /
• 제11권1호
• /
• pp.48-54
• /
• 2001

고순도알루미늄 유전체의 내부표면적을 증가시키기 위하여 1M의 염산 에칭용액에 첨가제를 사용했을 때 나타나는 에칭특성의 변화를 조사하였다. 염산용액에 에틸렌글리콜이 첨가된 혼합용액에서 에칭을 실시했을 경우 알루미늄 기지 표면에 미세하고 균일한 에치피트가 형성되어 표면적 증가 효과가 크게 나타났으며, 또한 양극 산화 후 측정된 정전용량의 결과에서도 에틸렌 글리콜이 첨가된 에칭액에서 제조된 유전체는 표면적 증가에 의한 높은 정전용량 값을 나타냈다.

• 보존과학회지
• /
• 제30권1호
• /
• pp.81-93
• /
• 2014

철원 도피안사 철조비로자나불좌상, 동해 삼화사 철조노사나불좌상, 평택 만기사 철조여래좌상은 통일신라에서 고려시대에 조성된 철불로서 균열, 탈락, 박리박락, 각종 오염물 등이 발생하였다. 방사선 투과촬영을 활용한 철불의 손상도 평가 결과, 철불 내부에서는 균열, 이격, 탈락, 주물공, 보수물질 등이 확인되었다. 그러나 철의 강도로 보아 외부로부터 큰 충격이 가해지지 않는 이상 현재의 상태를 유지할 수 있을 것으로 보인다. 철불의 제작에는 내형과 외형을 철심과 못을 사용하여 고정하였으며, 표면의 이음선과 양각된 명문, 따로 주조되어 결합된 손으로 보아 초중자주조법으로 조성되었을 것으로 판단된다.

• 기술혁신학회지
• /
• 제19권2호
• /
• pp.302-323
• /
• 2016

내부 연구개발 같은 공식적인 연구개발 활동은 기술혁신을 견인하는 중요한 요소로 인식되어 왔으나, 직무훈련, 진보된 생산기술의 도입, 디자인 활동 같은 다양한 부대적인 혁신 관련 활동들도 기술혁신 성과를 제고하는데 긍정적인 영향을 미칠 수 있다. 본고는 이러한 비공식적인 연구개발 활동 여부가 기업의 기술혁신 도입에 차이를 가져오는지, 공식적인 연구개발 활동 중심 집단과 비공식적인 연구개발 활동 중심 집단 사이에 기술혁신 도입 차이가 있는지를 2012년 한국 기술혁신 활동 조사 데이터를 사용하여 분석하였다. 실증분석 결과, 비공식적인 연구개발 활동이 공정혁신 도입에 유의한 차이를 유발할 수 있으며, 내부 연구개발 활동에만 집중하는 기업보다, 디자인 마케팅 같은 비공식적인 연구개발 활동을 함께 추진하는 기업들이 제품혁신을 더 활발히 도입하는 것으로 나타났다. 본 연구는 (1) 혁신주체들이 공식적인 연구개발 활동과 함께 비공식적인 연구개발 관련 활동에도 관심을 기울여야 하며, (2) 정부의 혁신지원정책도 이러한 점을 감안하여 수립되어야 함을 정책적 시사점으로 제시하였다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제40회 동계학술대회 초록집
• /
• pp.48-48
• /
• 2011

We have developed a chemically-driven top-down approach using vapor phase HCl to form various GaN nanostructures and successfully demonstrated dislocation-free and strain-relaxed GaN nanostructures without etching damage formed by a selective dissociation method. Our approach overcomes many limitations encountered in previous approaches. There is no need to make a pattern, complicated process, and expensive equipment, but it produces a high-quality nanostructure over a large area at low cost. As far as we know, this is the first time that various types of high-quality GaN nanostructures, such as dot, cone, and rod, could be formed by a chemical method without the use of a mask or pattern, especially on the Ga-polar GaN. It is well known that the Ga-polar GaN is difficult to etch by the common chemical wet etching method because of the chemical stability of GaN. Our chemically driven GaN nanostructures show excellent structure and optical properties. The formed nanostructure had various facets depending on the etching conditions and showed a high crystal quality due to the removal of defects, such as dislocations. These structure properties derived excellent optical performance of the GaN nanostructure. The GaN nanostructure had increased internal and external quantum efficiency due to increased light extraction, reduced strain, and improved crystal quality. The chemically driven GaN nanostructure shows promise in applications such as efficient light-emitting diodes, field emitters, and sensors.

• 대한치과보철학회지
• /
• 제43권5호
• /
• pp.622-632
• /
• 2005

Statement of problem: Silicone Index Tooth Tray impression system which does not use gingicord has a shortcoming. It takes time to remove internal wall of Silicone Index Tooth Tray for space of wash impression material. Purpose: This study was to evaluate whether providing certain space to impression body can prevent from doing complicated laboratory work. Material and methods: After mounting metal dies with shoulder and chamfer margins arbiturarily, SITT was produced using $Blu-mousse^(R)$. In one experimental group, wash impression was taken using $Fit-tester^(R)$ without removing interior surface of SITT and in the other group, wash impression was taken using $Fit-tester^(R)$ providing 0.5mm space in the SITT and then compared the differences in two groups. Results: 1. There was no significant difference between a group which did not allow space and a group which granted equal 0.5mm space. 2. There was no significant difference between gingival diameter, occlusal diameter of metal die that has shoulder margin and gingival diameter, occlusal diameter of metal die that has chamfer margin. 3. There was no significant difference between a group which did not take pick-up impression and a group which took pick-up impression through relining method using SITT 4. There was no significant difference between a group that poured immediately after taking primary impression and a group that poured after removing poured stone die. Conclusions: When taking an impression of an abutment using SITT impression system, it is considered to obtain clinically identical results between a group that did not grant a 0.5mm space within SITT for wash impression and a group which invest a space. Furthermore, it is considered possible to produce an individual die through secondary pouring.

• 한국한의학연구원논문집
• /
• 제7권1호
• /
• pp.39-54
• /
• 2001

This is a study on the methods of taking prescriptions in SANGHANRON (傷寒論), and after this, numbers of results have been obtained. SANGHANRON was written by Chang-Ki (張機) in the 2nd century, so it reflexes the usage of prescriptions of previous age indirectly. And gave affects on the methods of taking prescriptions to the oriental medicine doctors of next generation. Before Han-Dynasty (漢代), there were not so many publications connected with Oriental Medicine. Besides, some books couldn't hand down to next generation due to the gap of time and space. As time goes by, letters in medical books changed little by little, so contents connected with taking decoctions changed too. The effects of decoction and herb tea can be changed by the flexibility of methods of taking medicines, so we have to decide what kinds of taking methods should be taken and adapted to patients by the most effective way. There are many kind of methods of taking decocted prescriptions in SANGHANRON, so Chang-Ki selected the most appropriate method considering degree and position of disease and condition of patient. But nowadays, due to inconvenient procedure of taking medicines, some methos are not in common in clinical medicin. So this study was started to look back upon the changes of taking prescriptions and gave effort to find out the propriety of variation of taking prescriptions. In SANGHANRON, many kinds of taking prescriptions appeared from once a day to six times a day, except these, some prescriptions have to be taken little by little. These methods of taking prescriptions simplified as time pass by, but this change may give influence to the effect of medicine and finally we can't gain expected therapeutic value. So we have to distinguish the methods -though complicated and troublesome- in clinical medicine to make perfection more perfect in treating patients, and further studies have to be followed to prove the propriety of these methods.

• Clinical and Experimental Reproductive Medicine
• /
• 제13권2호
• /
• pp.153-159
• /
• 1986

The high rate of chromosomal abnormalities in patients with primary amenorrhea implies the need for routine screening for chromosomal abnormalities among such patients. This study was designed for the cytogenetic analysis of 236 patients with primary amenorrhea, which was referred to Yonsei University Medical Center, from January, 1, 1974 to December, 31, 1985. The results were as follows: 1. Of the 236 patients, 145 cases (61.4%) showed normal karyotype, and 91 cases (38.6%) showed chromosomal abnormalities. 2. Gonadal dysgenesis was found in 56 cases, consisting of 42 cases, Turner's syndrome, 12 cases, pure gonadal dysgenesis, and 2 cases mixed gonadal dysgenesis. a) Turner's syndrome was found in 42 cases, consisting of 18 cases of 45, X and 24 cases of mosaicism. b) Pure gonadal dysgenesis was found in 12 cases, consisting of 10 cases of 46, XX and 2 cases of 46, XY. c) Mixed gonadal dysgenesis was found in 2 cases, consisting of 1 case of 46, XY and 1 case of 45, X/46, XY. 3. Intersex was found in 80 cases, consisting of 35 cases of 46, XX, and 45 cases of 46, XY. 4. Congenital anomalies of reproductive system was found in 82 cases and all cases were normal karyotype.

• 디자인학연구
• /
• 제17권4호
• /
• pp.51-60
• /
• 2004

대표적인 고부가가치 산업의 하나인 의료기기 산업은 선진국과의 기술격차를 최소화하여 해외수출시장의 진입이 매우 용이한 분야임에도 불구하고 그동안 일반인에게는 생소한 분야로 인식되어 각종 제도와 정책적인 지원 등에서 소외받아왔다. 특히 효율적인 진료와 환자의 심리적 안정을 위해 의료기기의 제품디자인은 매우 중요한 요소임에도 불구하고 디자인에 대한 무관심과 인식부족으로 투자와 지원이 부족했었던 대표적인 분야이다. 따라서 본 연구는 국내 의료기기 산업의 현황과 국내외 시장환경에 대한 일반적인 고찰과 함께 현 단계에서의 디자인문제점을 제시하고 이를 해결할 하나의 대안으로 대표적 고부가가치 장비인 이동형 영상진단장비에 대한 디자인개발 프로세스를 진행하여 결과물을 도출하였으며 이를 통한 디자인경쟁력의 중요성을 부각시키고 의료기기산업의 후발 디자인추진업체에 하나의 기초자료와 모델을 제시하고 지속적인 디자인투자의욕을 고취시키는 역할을 하고자 한다.

• Restorative Dentistry and Endodontics
• /
• 제19권1호
• /
• pp.64-72
• /
• 1994

Zinc Phosphate Cement hand been used for about more than 100 years in luting of cast gold inlay. But many scientists had been trying to develop the new form of luting agent because the ZPC hand shown the lack of adhesiveness on the tooth structure and the toxicity to the pulp tissue. Recently many researches about the surface treatment of the cast body are being done to increase the adhesion of cement to it. The conventional Class I gold inlays were fabricated in the 20 permanent molars. After the internal surface of the cast body was sandblasted with $Al_2O_3$ particles and was tin-plated, the inlays were cemented with adhesive cement [G I cement and resin cement(Super-Bond & $Panavia_{EX}$)] and the evaluation on the adhesion pattern, adhesive strength and the fracture pattern of the adhesive cast gold inlay was compared to that of the cast gold inlay cemented conventionally with ZPC. The results were as follows : 1. The surface roughness of the cast body was increased significantly after sandblasting with the $Al_2O_3$ particles and the tin oxide layer, which was consisted of round particles, came into being. 2. The bond strength was in the order of Super-Bond, ZPC, Fuji I, $Panavia_{EX}$ group. The group cemented with Super-Bond showed statistically greater strength than the other groups(p<0.05). 3. The group cemented with ZPC was fallen apart by principal adhesion failure and that with Fuji I was by complete adhesion failure. But the group with Super-Bond showed pricncipal cohesive failure pattern and in the group with $Panavia_{EX}$, complete cohesive fracture pattern was shown and small protion of tooth structure was fractured out with cast body and the fractured surface showed the figure just as the enamel prism. 4. Various gaps were shown at the pulpal side regardless of little gap at the side walls of the cavity in all groups. Only the Super-Bond was attached to the tooth structure and the other cements were detached from both the tooth and the cast body.

• 한방안이비인후피부과학회지
• /
• 제12권2호
• /
• pp.53-66
• /
• 1999

This study has been carried out to investigate the effects of Dojuksan on the renal functions and internal secretion system, as water balance, urine volume, urinary excretion of sodium and potassium, free water clearance, urinary excretion of creatinine, plasma levels of artrial natriuretic peptide (ANP), plasma levels of aldosterone and plasma renin activity, comparing experimental group which Dojuksan water extract were administrated with control group. Sprague-Dawley rats, about 200-250 g, were used for this experiment. The results of this study were as follows: 1. Water balance decreased significantly after the administration of Dojuksan water extract. 2. Urine volume increased significantly after the administration of $100{\mu}l$ Dojuksan water extract per 100g rat. 3. Urinary excretion of sodium increased significantly but urinary excretion of potassium did not change after the administration of Dojuksan water extract. 4. Free water clearance decreased significantly after the administration of Dojuksan water extract 5. Urinary excretion of creatinine increased significantly after the administration of Dojuksan water extract 6. Plasma renin activity did not change after the administration of Dojuksan water extract 7. Plasma levels of artrial natriuretic peptide (ANP) did not change after the administration of Dojuksan water extract 8. Plasma levels of aldosterone decreased significantly after the administration of 200 ${\mu}Dojuksan water extract per l00g rat The results suggest that Dojuksan increase the urinary excretion of sodium. and thus reduce the water balance, which resulted from suppression of sodium reabsorption into renal tubule by increasing glomerular filtration rate and decreasing aldosterone.