• Journal of the KSME
• /
• v.44 no.4
• /
• pp.53-58
• /
• 2004

로봇의 백과사전적 의미를 보면, 사람의 손발과 같은 동작을 하는 기계라고 되어 있다 로봇이라는 말은 체코어의 '일한다(robota)'라는 뜻으로, 1920년에 체코의 작가 K. 차페크가 희곡 (로섬의 인조인간 : Rossum's Universal Robots)을 발표한 이래로 쓰이게 되었다.(중략)

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.8 no.1
• /
• pp.41-48
• /
• 2013

Waste Stone and Waste Stone Powder are recycling some cyclic aggregate only. And the greater part of Waste Stone and Waste Stone Powder are reclaining or neglecting. To solve this problem, the government is proceeding development of cementitious scagliola using waste stone and waste stone powder. However, quality standard for cementitious scagliola using waste stone and waste stone powder has not been established. So cementitious scagliola using waste stone and waste stone powder has problem of quality assurance. Therefore in this study, developed standard for Evaluating Performance of cementitious scagliola using waste stone and waste stone powder through survey of international standard.

• Journal of Chest Surgery
• /
• v.36 no.2
• /
• pp.63-72
• /
• 2003

Although a variety of synthetic vascular grafts are available in modern vascular surgery, no ideal prosthesis ha,4 yet been developed. Small-caliber vascular grafts with low flow, as used in the lower extremity, continue to become thrombosed at unacceptable rates. We have developed and evaluated the new antithrombogenic blood contacting surfaces in canine model. Material and Method: Two now antithrombogenic blood contacting surfaces(Polyvinylalcohol -Polyurethane(PVA-PU) blend and natural Graphite-polyurethane(G-PU) blend) have been developed and evaluated in canine model, using vascular grafts and patches. The luminal surfaces of the test vascular grafts(5 mm ID) were fabricated by dipping a glass rod in PVA-PU blend solution(50 % PVA) using phase separation method. Mongrel dogs of either sex weighing 18-22 kg were anesthetized by endotracheal intubation using halothane and their lungs were ventilated with a volume-cycled ventilator, Maintenance anesthesia with 0.5-1.0% halothane and supplemental oxygen was used. Two pairs were used for comparison in the bilateral femoral arteries for both vascular grafts(PVA-PU vs. PU) and vascular patches(G-PU vs. PU). Bilateral groin incisions were made and the arteries were exposed and clamped. After an excision of 1 cm of the artery between clamps, a grail of 2.5 cm in length was implanted end-to-end using 6-0 polypropylene suture. The vascular patch was implanted as a form of on-lay patch. Animals were sacrificed at 1, 2, 4, 6, 8 and 16 weeks for vascular grafts and 1, 2. 4 and 6 weeks for vascular patches. Result The vascular grafts of PVA-PU blends showed patent lumina in the 2 and 16 weeks animals, while those of PU showed a patent lumen in 2 weeks animal. PVA-PU graft of 16 weeks showed a fairly clean luminal surface. A light microscopic finding of this graft demonstrated good tissue infiltration through porosity, The animals with vascular patches showed patent arteries in both groups except 2 weeks animal. Scanning electron microscopy of the luminal surfaces of G-PU patches in 4 and 6 weeks animals showed endothelial cell covering with microvilli. PU patches showed qualitatively less endothelial cell covering. Conclusion: In conclusion, PVA-PU and G-PU blends can be a promising blood contacting surfaces for application in a synthetic vascualr graft. However, further animal study is needed to determine the real long-term effects of these methods of surface modifications.

• The Science & Technology
• /
• v.28 no.5 s.312
• /
• pp.14-15
• /
• 1995

사람이 다이아몬드를 만든다는 것은 지금부터 30년전만 해도 하나의 꿈에 불과했다. 그러나 지금은 초고압이 만들어내는 요술의 힘을 빌어 인조 다이아몬드를 공장에서 쉽게 만들고 있다. 이 요술쟁이 초고압은 과연 어떤 것일까? 우리나라에서도 인조 다이아몬드 개발에 성공, 88년부터 상품화해 수출까지 하고 있는데 이러한 신비로운 초고압의 세계를 훑어본다.

• Journal of Chest Surgery
• /
• v.29 no.8
• /
• pp.836-843
• /
• 1996

Histologic, and scanning electron microscopic observa ions were made of 12 biopsy specimens from polytetrdiluoroethylene (PTFE) grafts that had been Implanted as systemic-pulmonAry shunt for improving oxygenation of cyanotic congenital heart disease and harvested near the end of pulmonary artery side at the time of redo shunt or tonal correction between 1985 and 1992. The types of shunt operation are modified Blalock-Taussig shunt in 10 cases, Waterston-Cooley shunt in 1 And Potts shunt in 1 case. The 5 mm PTFE graft was used In 10, 4mm in 1 and 6mm in 1 case. The mean duration of implantalion was 0 $\pm$ 14.1 months(rl.on 12 months to 55 months). The plAtelets were aggregated between gaps'of Coretex surface and intimal thickening was noted about 10 to 20 months after implantation. Endothelial cells were found in the 40-months patent PTFE graft by light and scanning electron microscopy. In the specimen of poor flow or zero flow graft, severe intimal hyperplasia and thrombi which was made of platelets were noted . Based on this experience, we think that the patency will be maintained well if the connective tissue could be Hxed firmly over the Inner layer of the Goretex and the endothelial cell layer sllould form over the con- nective tissue and platelet aggregation should be prevented.

• Journal of Chest Surgery
• /
• v.42 no.4
• /
• pp.487-491
• /
• 2009

Background: Salvaging prosthetic arteriovenous grafts can be performed using surgical or endovascular techniques. We conducted a retrospective analysis to compare the efficacy of these two methods for restoring dialysis graft function. Material and Method: We studied 41 patients who had received surgical thrombectomy with revision (Group A) or percutaneous thrombectomy with angioplasty (Group B) from January 2006 to December 2007. We compared them according to the patient characteristics and the location of stenotic lesions, and we analyzed the post-intervention primary patency rates. Result: 21 patients underwent surgery and 20 patients underwent percutaneous balloon angioplasty. There were no significant differences of the patients' characteristics between the two groups. Venous anastomotic stenosis was the most common cause of graft thrombosis in both groups. In Group A, 90.5% of the grafts remained functional at 6 months and 38.1% remained functional at 12 months. In Group B, 55.0% of the grafts were functional at 6 months and 20.0% of the grafts were functional at 12 months. The post-intervention primary patency rate was significantly better in Group A (p=0.034). Conclusion: Surgical treatment resulted in significantly longer post-intervention primary patency in this study, and this supports its use as the primary method of management for most patients in whom dialysis graft obstruction develops.

• Asian Journal of Turfgrass Science
• /
• v.24 no.1
• /
• pp.62-66
• /
• 2010

Synthetic turfgrass was developed for longer durability than natural turfgrass. As synthetic turfgrass use increases, disadvantage was exposed and composite turfgrass was designed to reinforce disadvantage of synthetic turfgrass. However, A few researches were conducted to evaluate composite turfgrass in South Korea. Therefore, this research was conducted to select a turfgrass species to maximize practical use of composite turfgrass. In 14 Oct. 2006 synthetic turfgrass was established in the research center in Hanul Sports Turf, Inc. located Hapcheon-Gun, Gyunggnam province. Kentucky bluegrass, Tall fescue, and a mixture of Kentucky bluegrass and Perennial ryegrass were used to combine with synthetic turfgrass. Wide and narrow types of synthetic turfgrass were used. As temperature increase, coverage of tall fescue and the mixture reduced but Kentucky bluegrass had the best result of turfgrass coverage although there were no differences on turfgrass quality among types of turfgrass.

• Applied Chemistry for Engineering
• /
• v.10 no.4
• /
• pp.592-598
• /
• 1999

Exterior finishing materials of artificial stones are manufactured with the mixture of water, cement, stone powder and light-weight aggregate. In this research, we tried to find a way of increasing the physical properties and decreasing the manufacturing cost of artificial stone. So, we used ${\beta}$-NSF base surfactant and vinsol base surfactant to the artificial stone mixture instead of light-weight aggregate. The optimum dosage of the ${\beta}$-NSF and vinsol surfactants for artificial stone are found to be 1.0 wt % of cement, respectively. The physical properties increased ca. 20% and the durability for freezing & thawing of the new artificial stone increased ca. 300%. While the manufacturing cost of the new artificial stone decreased as much as 30%.

• Journal of the Korea Institute of Building Construction
• /
• v.14 no.3
• /
• pp.237-243
• /
• 2014

The environmental problem is serious due to global warming In a concrete industry, the effort to reduce the problem of the destruction of environment arising from the indiscriminate use of limestone that is the raw material of cement and aggregate and the exhaustion of resources are continually emphasized In this research, the waste porcelain and waste glass that are the natural aggregate substitute materials were mixed and were applied. In addition, the magnesia phosphate composite and fly ash are mixed with a cement substitute material and the properties of the artificial stone was examined. Density, water absorption, rate of aggregate on the surface, compressive strength, and flexural strength were performed. As a result of the test, it is that waste glass with 60% and waste porcelain with 70% are the most excellent mix to produce the artificial stone.

• Korean journal of food and cookery science
• /
• v.5 no.1
• /
• pp.15-21
• /
• 1989

These experiments were carried out to study the factors affecting quality and textural characteristics in the preparation of artificial gluten meat (AGM). Effects of amounts of ingredients on properties of AGM were summarized as follows: 1. The more amounts of water increased, the higher L and b values became, and AGM, therefore, became bright and yellow in color. The more increased the amount of water, the more decreased shear force, hardness and chewiness, but the water holding capacity increased. The 100% of water added sample approached to raw beef in L value, $\Delta$0E, hardness and chewiness. 2. The mixing ratio of walunt and com oil more affected on color than on texture, and the proper ratio was 30% of walunt and 10% of oil. 3. In the case of interactions of oil and water, water amounts affected more on color, shear force, chewiness and the water holding capacity than on oil. AGM mixed with the ratio of 10% of oil and 100% of water approached to raw beef.