• Journal of Applied Biological Chemistry
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• v.51 no.1
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• pp.28-35
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• 2008

The physico-chemical properties of kapok fibers were altered via the combination processes of chlorite-periodate oxidation, in order to assess their efficacy as a heavy metal adsorbent. The chemically-oxidized kapok fibers were found to harbor a certain amount of polysaccharides, together with lowered lignin content. This alteration in lignin characteristics was clearly confirmed via FTIR and NBO yield. Moreover, chemically oxidized kapok fibers retained their hollow tube shape, although some changes were noted. The chemically oxidized kapok fibers evidenced elevated ability to adsorb heavy metal ions with the best fit for the Langmuir adsorption isotherm model. Three cycles of adsorption-desorption were conducted with in-between regeneration steps. Our experimental results indicated that chemically oxidized kapok fibers possessed excellent adsorption characteristics, and the modified kapok fibers could be completely regenerated with almost equimolar diluted sodium hydroxide. Pb, Cu, Cd and Zn ions evidenced adsorption rates of 93.55%, 91.83%, 89.75%, and 92.85% on the chemically oxidized kapok fibers. The regeneration efficiency showed 73.58% of Pb, 71.55% of Cu, 66.87% of Cd, and 75.00% of Zn for 3rd cycle with 0.0125N NaOH.

• Journal of the Korea Concrete Institute
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• v.24 no.1
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• pp.71-78
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• 2012

In order to improve the shear strength of conventional pre-tensioned spun high strength concrete (PHC) pile, concrete-infilled composite PHC (ICP) pile, a PHC pile reinforced by means of shear reinforcement and infilled concrete, is proposed. Two types of specimens were cast and tested according to KS (Korean Standards) to verify the shear strength enhancement of ICP pile. Based on the test results, it was found that the KS method was not suitable due to causing shear failure of ICP pile. However, shear strength enhancement was clearly verified. The obtained shear strength of the ICP pile was more than twice that of conventional PHC pile. In addition, the shear strength of ICP pile reinforced with longitudinal reinforcement was estimated to be more than 2.5 times greater than that of conventional PHC pile. The allowable shear force of ICP pile, which was determined by the allowable stress design process, indicated a large safety factor of more than 2.9 compared to the test results.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.15 no.1
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• pp.1-28
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• 2011

Objectives: A study on the importance and consistency of pulse-daignosis in the Dongeuibogam Methods: We used Deyeuk Dongeuibogam of Dongeuibogam publishing company from original photographic edition. Results: The frequency of 27 mek (pulse condition) in Dongeuibogam is as in the following. Bumek (Floating pulse) appeared 120(8.9%) times, wanmek (moderate pulse) appeared 28(2%) times, chokmek (running pulse) appeared 7 (0.5%) times, gyumek (hollow pulse) appeared 19 (1.4%) times, saekmek (uneven pulse) appeared 33 (2.4%) times, sapmek (uneven pulse) appeared 51 (3.8%) times, kyulmek (knotted pulse) appeared 18 (1.3%) times, whalmek (slippery pulse) appeared 69 (5.1%) times, chimek (slow pulse) appeared 43 (3.2%) times, demek (intermittent pulse) appeared 13 (1%) times, silmek (replete pulse) appeared 45 (3.3%) times, bokmek (deep-sited pulse) appeared 29 (2.1%) times, neomek (firm pulse) appeared 4 (0.3%) times, hyunmek (taut pulse) appeared 110 (8.1%) times, yumek (soft pulse) appeared 20 (1.5%) times, dongmek (short and rapid pulse) appeared 16 (1.2%) times, kinmek (tense pulse) appeared 67 (5%) times, yakmek (weak pulse) appeared 46 (3.4%) times, semek (thready pulse) appeared 62 (4.6%) times, hongmek (full pulse) appeared 50 (3.7%) times, jangmek (long pulse) appeared 14 (1%) times, sakmek (rapid pulse) appeared 103 (7.6%) times, mimek (indistinctive pulse) appeared 65 (4.8%) times, danmek (short pulse) appeared 16 (1.2%) times, demek (large pulse) appeared 106 (7.9%) times, chimmek (deep pulse) appeared 112 (8.3%) times, heomek appeared 70 (5.2%) times, sanmek (scattered pulse) appeared 14(1%)times. Conclusions: We can know Donguibogam is given on the basis 27mek (pulse condition), because the frequency of 27mek (pulse condition) is high. But there are another expressions. So we can not say that Donguibogam is consistent in expressing mekbub(the way of pulse-diagnosis).

• Journal of Korean Society of Steel Construction
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• v.24 no.6
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• pp.743-751
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• 2012

This paper investigates an experimental behavior of circular columns and beam-columns made of HSB600 high strength steel as a fundamental study to enhance the applicability of HSB steel. The applicability of the current Standard such as KBC and Eurocode 3 is also evaluated. A total of six specimens are fabricated and tested. The main parameters are slenderness ratio(KLe/r = 12, 14, 40, 65), diameter-to-thickness ratio(D/t = 25, 40), and eccentricity ratio(e/D = 0, 0.5). It is drawn from the experiment that both the KBC and Eurocode 3 can be used to predict the strength of circular columns and beam-columns made of HSB600 high strength steel.

• Tribology and Lubricants
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• v.22 no.4
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• pp.190-195
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• 2006

A simple and effective analysis method is presented for gaining a complete transient temperatures on the internal and external surfaces of a 40 mm gun tube subjected to a series of rapid firings. Two series of temperature data for both Hs and As were measured by using two rapid response k-type surface thermocouples near the firing origin and the muzzle. With other available temperature data, patterns of temperature variations of the gun tube as a function of time variable were driven through complete evaluations of the data. It is found that overall temperature gradients which increase exponentially toward saturation temperature, actually consist of a series of linear temperature gradients corresponding to the firing sequences. Under the similar firing sequences, patterns of temperature variations fur both the surface temperatures near the chamber and those near the muzzle were found to have linear temperature gradients with different values and the same response frequencies, i.e. they had peaks and lows in temperatures at the same time. The resultant complete temperature data can be used as the fundamental bases for analysis of thermoelastic properties of the materials such as thermal strain and stress, and f3r the prediction of cannon tube life-time through calculation of wear rate.

• Journal of Chest Surgery
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• v.28 no.5
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• pp.499-503
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• 1995

Since the insertion of self expandable metalic stent[SEMS has became popular method for hollow organ stenosis, many attempts for further apply the stent to airway stenosis as an simple procedure has been made, but intrabronchial migration of stent or occurrence of inflammatory granuloma around stent develop occasionally and sometimes it worsen bronchial stenosis further more. This report describes 2 case of surgically treated bronchial restenosis in whom intrabronchial stent were applied for release of bronchial stenosis. Our surgical option was pneumonectomy and bronchoplasty with sleeve right middle and upper lobectomy respectively. During the operation we found the SEMSs were tightly impacted in restenotic bronchial lumen with overgrowth of granulation tissues. The bronchial obstructions occupied more than 90% of lumens in both cases, and needed much complicated procedure to be relieved. Therefore, even though the insertion of SEMS remains as a prcedure determined by the physician`s preference, it has to be considered prudently that the use of SEMS can cause severe restenosis and the surgeon has more difficulties in performing segmental resection of restenotic bronchus in patient with SEMS previously inserted. Throughout these experiences we can conclude that the insertion of SEMS must be performed only in very selected cases of bronchial stenosis.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.254-254
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• 2013

마그네트론 스퍼터링은 그 단순한 구조로 인하여 신뢰성과 확장성이 높은 기술이다, 이로 인해 DLC, ITO 등의 산업 분야에서 많이 사용하는 박막 공정 기술이다. 하지만 인듐과 같은 희토류 금속의 가격이 최근 상승함에 따라 나타난 낮은 타겟 효율성의 문제와 낮은 파워 밀도로 인한 기판의 추가적인 bias 추가에 따른 비용상승, 그리고 reactive 스퍼터링 시 낮은 증착률 등의 문제점들 또한 존재한다. 이러한 단점들을 해결하기 위해 많은 연구들이 이루어 졌으며, 높은 파워 밀도를 위해 High power Impulse Plasma Magnetron Sputtering (HIPIMS) 기술과 타겟 사용률을 높이기 위한 High Target Utilization Sputtering (HITUS) 등의 기술 등이 개발되었다. 본 연구에서는 직류 전원을 사용한 High density Plasma Sputtering System (HIPASS)이라 명하는 고밀도 원거리 플라즈마 소스를 이용한 스퍼터링 이용해 증착한 박막의 특성을 연구 하였다. Hollow cathode discharge에서 발생한 고밀도 플라즈마가 외부 유도 자장 코일에 의하여 타겟 표면까지 도달하게 되며, 스퍼터링 타겟의 고전압 bias에 의해 플라즈마 이온들이 가속이 이루어져 스퍼터링 공정이 이루어 지게 된다. 본 연구의 공정에서 타겟 사용 효율은 최대 90%까지 이며, 원거리 플라즈마 소스에서의 이온으로 스퍼터링을 실시함으로 인해 스퍼터링 전압과 전류의 독립적인 조절이 가능 하다. 본 연구에서 HIPASS을 이용하여 기판에 추가적인 전압 인가 없이 Ti 타겟과 아르곤/질소 혼합가스를 사용하여 TiN 박막을 증착 하였다. TiN의 증착률은 약 44 nm/min였으며, 이 박막의 XRD 분석 결과 TiN (111), (200), (220) 면들이 관찰이 되었다. 높은 스퍼터링 입자 에너지에서 증착 된 TiN 박막에서 우선적으로 나타나는(200)과 (220) 면들이, 본 실험에서는 기판에 추가적인 전압인가 없이도 우선방위 성장을 보였다. 이 박막의 micro-hardness 측정 결과 약 34.7 GPa이며, 이는 UBM 이나 HIPIMS에서 보여주는 결과에 준하거나 그 이상의 수치이다. 이와 같은 결과는 본 연구에서 사용한 HIPASS 증착 공정이 높은 스퍼터링 입자 에너지를 가지기에 고밀도의 TiN 박막이 증착 된 결과로 볼 수 있다.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.104-104
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• 2012

아웃도어용 스포츠웨어 의류분야는 소비자들의 욕구가 기능성, 착용감, 패션성을 매우 중시하는 고감성, 고기능성 제품특성을 요구하고 있으며 이를 가장 충족시킬 수 있는 패션 트랜드로서 보온, 경량화 제품이 가장 급부상하고 있는 아이템이다. 경량성의 쾌적 스포츠 웨어에 사용되는 주요 합섬소재인 PET, Nylon을 이용하여 소재의 세섬화, 중공 소재를 통한 제품 개발이 대부분으로 보온, 경량, 속건 등 의복에서의 쾌적 기능성을 개선하기 위하여 개발되는 소재 및 제품의 경량화, 보온 및 흡한속 건성 부여를 통한 기능 요소와 신질감 발현의 촉감요소를 통한 차별화 된 제품개발이 요구되고 있다. 보온 기능성을 부여하는 기술로써 가장 일반적인 기술은 섬유 내부에 중공을 형성하여 경량성과 보온성을 동시에 가지는 기능성 원사 제조 기술과 섬유 내에 열에너지를 흡수할 수 있는 물질을 넣어 외부의 태양광을 섬유내로 흡수하여 열에너지로 전환, 축적함으로서 보온성을 향상시키는 방식이 있다. 주로 경량 보온의 동시 발현을 위하여 중공 형성을 통한 보온 소재 개발이 활발하게 일어나고 있는 실정이다. 가장 많은 수요를 차지하고 있는 경량 보온성 중공사의 경우, 강도 저하, 염색 불량 등의 공정 애로점이 발생하며, 제직 및 가공 공정 시 원사 내 중공이 찌그러짐이 발생하므로 완제품 제조 후에는 중공의 기능이 제대로 발현되지 못하는 문제가 발생한다. 또한 알칼리 또는 용제를 사용하여 후용출 하는 중공사의 경우, 공정이 복잡함은 물론 환경에 유해한 공정이다. 특히, 감량 후 직물의 인열강도는 감량 전과 비교하여 감소하게 되는데 이는 이용성 polymer가 용출되면서 생긴 중공에 의해 섬도가 감소되어 강도가 저하됨을 알 수 있다. 따라서 Sheath 부분에 최대한 손상을 주지 않으면서 Core 부분을 완전 용출 시킬 수 있는 감량 조건을 확보할 필요가 있다. 이에 보온성, 경량성의 기능을 극대화시키고, 중공률 유지하는 최적 용출 가공 조건을 확립하고자 연구하였다.

• Journal of Powder Materials
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• v.10 no.6
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• pp.383-389
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• 2003

As in other areas of materials technology, the tendency towards light weight constructions becomes more and more important also for powder metallurgy. The development is mainly driven by the automotive industry looking for mass reduction of vehicles as a major factor for fuel economy. Powder metallurgy has to offer a number of interesting areas including the development of sintered materials of light metals. PM aluminium alloys with improved properties are on the way to replace ferrous pars. For high temperature applications in the engine, titanium aluminide based materials offer a great potential, e.g. for exhaust valves. The PM route using elemental powders and reactions sintering is considered to be a cost effective way for net shape parts production. Furthermore it is expected that lower costs for titanium raw materials coming from metallurgical activities will offer new chances for sintered parts with titanium alloys. The field of cellular metals expands with the hollow sphere technique, that can provide materials of many metals and alloys with a great flexibility in structure modifications. These structures are expected to be used in improving the safety (crash absoption) and noise reduction in cars in the near future and offer great potential for many other applications.

• Journal of Conservation Science
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• v.25 no.4
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• pp.411-420
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• 2009

A series of scientific analyses, including ICP-AES, microstructure, and TIMS, were carried out on 5 bronze spoons among 14 bronze artifacts excavated from the Ok-dong site in Andong, North Gyeongsang Province. The results of analysis showed that the bronze spoons were formed from an alloy of no more than 75% Cu and 21~23% Sn, placing it in the category of brassware, with trace elements such as Pb, Fe, and Zn. In particular, plumbum Pb contents of which traces of 0.04% were found, appears to have been added as an impurity during smelting. The microstructure of the bronze spoons suggests that the casting process involved using a spoon-shaped hollow mold, followed by an ropid-cooling process after the shape was perfected at approximately $586^{\circ}C$. After comparison of data measured from thermal ionization mass spectrometry (TIMS) of galena from Korea, China, and Japan, it appears that the raw materials for the bronze spoons included galena (lead sulfide) produced from the southern part of China.