공침법에 의한 BiDy₂Fe_(5)O_(12) 결정형 나노입자 분말의 제조 및 응용 연구

홍영대,조정환,김태엽,전성욱,홍영명 고신대학교 자연과학연구소 2007 고신대학교 자연과학연구소 논문집 Vol.14 No.-

금속산화물들은 각종 산업재료로서 유용하며 더욱이 그것들의 결정형 나노입자를 경제적으로 제조하는 기술은 21세기 첨단산업에 매우 중요하다. 저자들은 前報에서 화학합성법에 의한 각종 금속산화물의 나노입자를 제조하는 표준공정법을 연구하여 보고하였다. 본 연구에서는 그 표준공정법을 이용하여, 가넷의 일종인 BiDy_(2)Fe_(5)O_(12) 결정 나노입자 분말을 제조하고 그것의 자성체로의 응용을 위해 제품특성을 조사하었다. 가네트 제조과정에 필요한 침전물은 제품설계에 의거 몰비로 계산된 Bi, Dy, Fe의 질산염들의 혼합수용액에 침전제로서 pH NH_(3)-NH_(4)CI 완충용액 일정량을 가하여 얻어졌다. 이렇게 제조된 침전은 열처리과정을 거처 BiDy_(2)Fe_(5)O_(12) 결정형 나노입자 분말로 만들어졌다. 얻어진 제품의 입자크기, 조성, 결정구조 및 광자기성 등 특성시험이 SEM, ICP, XRD, 그리고 VSM 등을 사용하여 실시되었다. 각종 분석법을 사용하여 제품의 특성을 조사한 결과, 최초에 설계한 대로의 자성체가 나노 크기의 분말로 얻어졌으며 이것을 통하여 전보에서 확립한 표준공정법의 유효성도 입증되었다. Metallic oxides are useful as various industrial materials. Futhermore, the cost-effective techniques of fabricating the crystalline nanopartides of metallic oxides are very important for the high-tech industries of the 21 century, In the previous study, the authors reported the standard process for the preparation of crystalline nanoparticles of metallic oxides by chemical synthesis, In this study, BiDyzFesOiz nanoparticles were prepared by using the reported standard process and the characteristics of the product were investigated for applicability as magnetic substance. The precipitation needed for manufacturing process of garnet was made by adding the NH_(3)-NH_(4)CI buffer solution of pH 10 to the mixed solution of bismuth (III) nitrate, dysprosium(III) nitrate and iron(III) nitrate. The amount of each nitrate was calculated by the designed mole ratios. The nano-size crystalline powders of BiDy_(2)Fe_(5)O_(12) were earned by heating the precipitation at 800℃ for 4 hours in air. The characterizations, such as particle size, composition, crystal structure and magneto-optical property of garnet were tested by SEM, ICP, XRD, and VSM analyses. The results of the analyses showed the following two facts. First, a good magnetic substance of BiDy_(2)Fe_(5)O_(12) was earned as crystalline nano-size powders according to the original design. Next, the established standard process for the fabrication of METALLIC oxides nanonartieles was approved as a very effective method.

韓國産 복어毒의 毒性學的 硏究

洪思澳,劉永瓚 成均館大學校 科學技術硏究所 1983 論文集 Vol.34 No.2

Tetrodon poisoning also known as fugu poisoning, occurs chiefly in countries surrounding the South China Sea. It has been known for long time that tetrodotoxin which is the purified toxic principle is responsible for the poisoning. Crystalline tetrodotoxin is the most potent of the substances that can interfere with the production of action potentials in excitable cells and also unique in action only on changes in sodium permeability. It was reported that the occurence of tetrodotoxin as well as its distribution in the tissues is varied from species to species. Furthermore, the seasonal variation of toxicity was observed in ovaries of female tetrodon fish. Fugu ocellatus obscurum which is one species of tetrodon families inhabit only around Yellow Sea of Korea and Yantzu-Chiang of China. In this study, tetrodotoxin was extracted and purified from Fugu ocellatus obscurum and the toxicity of the tetrodotoxin was compared with the toxin from other species. In addition, the toxicological and pharmacological tests were performed and the results were as followings. 1. Among the various tissues of Fugu ocellatus obscurum, ovaries, liver and bile juice exhibited the potent toxicity while skin and testis of tetrodon fish showed relatively low toxicity. 2. LD_50 of the crude tetrodotoxin was about 11.8 ㎍/kg and that of the purified toxin. was 11.2㎍/kg 3. Infrared spectrum of the purified tetrodotoxin was almost exactly same pattern as the spectrum of standard tetrodotoxin. 4. The gas chromatographic isolation of TMS, derivatized substance of C_9-base was useful on a OV-101, especially, owing to the selective sensitivity for detection of TSD, the assay of tetrodotoxin in microquantity has been analyzed successfully. Also, tetrodotoxin could identified by means of GC/MS obtained from molecular ion at m/e 407 and fragment at m/e 392 (M-15) due to the C_9-base TMS. 5. The twitch tension of gastrocmemius muscle induced by tibial nerve stimulation was reduced gradually by the cumulative tetrodotoxin (5㎍/kg every 10 minutes) upto 30 minutes, and then the tension was completely abolished. The blood pressure and heart rate, however, showed maximal depression at the final concentration of 10㎍/kg of the tetrodotoxin, and no further depression thereafter. 6. In the isolated rabbit atria, the tetodotoxin produced minimal depression. In the isolated rabbit duodenum, a large doses of tetrodotoxin caused dose-related increase of motility. But pretreatment with tetrodotoxin did not affect the acetylcholine of norepinephrine response in the isolated duodenum.

기계적 피로결함 시험편 제조 및 결함 크기 평가

홍재근,김우성,손영호,박반욱 한국비파괴검사학회 2003 한국비파괴검사학회지 Vol.23 No.1

원자력발전소의 안전성등급 기기에 적용되는 비파괴검사는 실제 결함을 실현한 시험편을 사용하여 결함 탐지능력을 검증하도록 하는 기량검증이 요구되고 있다. 가동중인 원전에서 발생 가능한 균열으로는 기계적 피로균열, 열 피로균열 및 입계부식균열 등이 있으나 본 연구에서는 기계적 피로균열을 대상으로 하였다. 인장 피로하중을 사용하여 기계적 피로결함을 제조하기 위해서 시험편을 설계하였고 원하는 피로결함 파면의 조도를 얻기 위해서 인가하중의 크기 및 사이클 수를 조절하여 피로결함을 발생시켰다. 발생된 결함에 대한 정확한 크기와 위치에 대한 물리적 정보를 얻은 후에 결함이 설계된 크기와 위치에 존재하도록 기밀용접을 실시하였다. 기밀용접 후 잔여 용접 홈은 가스 텅스텐 아크용접 및 플럭스 코어드 아크용접으로 채워졌다. 최종 완성된 피로결함 시험편을 방사선투과검사 및 초음파탐상검사를 통하여 검사한 결과, 설계된 길이와 깊이로 피로결함이 형성되었음을 확인하였다. Performance demonstration with real flawed specimens has been strongly required for nondestructive evaluation of safety class components in nuclear power plant. Mechanical or thermal fatigue crack and intergranular stress corrosion cracking could be occured in the in-service nuclear power plant and mechanical fatigue crack was selected to study in this paper. Specimen was designed to produce mechanical fatigue flaw under tensile stress. The number of cycles and the level of stress were controlled to obtain the desired flaw roughness. After the accurate physical measurement of the flaw size and location, fracture surface was seal-welded in place to ensure the designed location and size. The remaining weld groove was then filled by using gas-tungsten arc welding(GTAW) and flux-cored arc welding(FCAW). Results of radiographic and ultrasonic testing showed that fatigue cracks were consistent with the designed size and location in the final specimens.

골재생산과 관련한 터널작업에서 효율적인 심빼기 발파공법

임한욱,김재홍,조영동 강원대학교 부설 석재복합신소재 제품연구센터 2000 석재연 논문집 Vol.5 No.-

실린더 컷 심빼기 공법은 일반적으로 터널단면에 관계없이 널리 쓰이는 방법이다. 본 연구에서는 종래의 실린더 컷 공법을 개선한 새로운 방법을 제안하였다. 제안한 방법의 특징은 발파당 굴진장을 증대시킬수 있는데 이를 요약하면 다음과 같다. 발파당 굴진장은 평균 3.8m 이상으로 종래의 심빼기 바법 경우 천공장의 90~95% 인데 비하여 제안한 방법은 천공장의 99.5%까지 가능하다. 또한 비장약량은 1.363에서 1.297 kg/㎥로 약 5%가, 비천공장은 2.393에서 2.130 kg/㎥로 약 8%가 감소되었다. 이외에 발파진동, 비산거리, 파쇄입도면에서도 종래 방법보다 양호함을 확인하였다. The cylindrical cut is most frequently used in tunnelling regardless of their dimensions. In this study the new parallel cut is proposed to raise advance per round, which is considered to be an elevation of the traditional cylinder cuts. The main results of this study are as follows; The average advances per rounds in new cuts can reach 99.5% of drilling length. That of traditional cylinder cuts are known approximately 90~95%; Specific charge weight is approximately reduced 5%(1.363→1.297 kg/㎥); Specific drilling rate is also reduced 8% compared to that of cylinder cut(2.393→2.130 kg/㎥); Vibrations, fly rock, and fragmentation produced by the new blast are to be proved superior to those of the traditional cylinder cuts.

구내신연장치를 이용한 치조골증대술 후 임프란트 매식 : 치험 5예 REPORT OF 5 CASES

이용욱,박충열,송종운,박홍주,김영운,오희균,유선열 대한악안면성형재건외과학회 2002 Maxillofacial Plastic Reconstructive Surgery Vol.24 No.2

Successful alveolar ridge augmentation by distraction osteogenesis method has been reported previously. There are several types of devices for alveolar ridge augmentation. In this paper, a new intraoral distraction device was used on the severe atrophic mandible in order to distract an alveolar ridge vertically in 5 patients. Mean amount of distracted alveolar ridge was 7.4㎜ (5∼9.5㎜). Dental implants were placed in the distracted alveolar bone and good osseointegration was obtained in all patients. Mean follow up period is 2years 6months (7months∼4years 9months). No complications, such as infection or resorption was observed in all patients. Alveolar ridge augmentation by gradual distraction seems to be a safe, simple and reliable procedure.

桔梗의 內部構造規格設定에 관한 硏究

金鍾旭,金弘寯,朱榮丞,陸相元,韓京植 대한본초학회 2000 大韓本草學會誌 Vol.15 No.2

In order to strengthen objectivity and availability of oriental herb medicine, the standard formula for herbs has been attempted to set up by experimenting and documentary testing original herbs which were recorded in authorized document. The object herb medicines are Platycodi Radix. The internal morphological standard in this study is expected to supply the search for several physiochemical reaction, biological reaction, determination of indicator material and identification of gene with basic sources in the future. The result of study is as follows; In the shape of real herbs, I compared current herbs in market with original herbs which were just collected or were on the course of drying. It was possible that the internal shape could be identified by using microscope after butanol series. In powder herbs, it was possible to purify the shape by microscope through maceration of natural and powder herbs. Despite such a useful character, it was difficult to deal with powder herbs because it was uncertain to make a standard for them on account of the crush of these tissue. Since powders shape of herbs in a few documents were regard not as the powder shapes of natural herbs but as the maceration state of them. It is suggested that we should inspect the original herbs which are not crushed yet with a microscope in order to identify crushed shape of powder herbs from now on. An Additional standard establishment including physiochemical reaction and gene research is required in order to supplement the fault of this search.

호스트기반 라우팅을 이용한 마이크로 이동성 관리

朴昡旭,安弘榮 弘益大學校 科學技術大學 大學院, 2004 産業技術 Vol.14 No.-

Mobile IP provides convenient and extensible global mobility management protocol. However It does not support fast Handoff and Paging. Local mobility management protocols like Cellular IP, HAWAI and Hierarchical Mobile IP are proposed to support frequent Handoff in intra IP domain. In this paper, we propose a new host-based routing algorithm which maximizes the advantage of extra links using controlled flooding. Simulation results show that a new routing algorithm has a better performance in packet loss and throughput metric.

SIP를 이용한 멀티 유저 컨퍼런스 서버 설계와 구현

安弘榮,朴昡旭 弘益大學校 産業技術硏究所 2005 産業技術 Vol.15 No.-

SIP(Session Initiation Protocol) is Application-layer control protocol for creating, modifying and terminating multimedia sessions or calls with one or more participants. SIP is an IETF standards track protocol specified in RFC 3261. Recently many Application services using SIP are researched. In this paper, we present Multi-user Conference Server Design and Implementation based on SIP. We show multi-party Conference server model, explain extended SIP methods for conferencing and their scenario.

牙山人工湖의 理化學的水質調査

沈英燮,羅圭煥,洪思澳 成均館大學校 1978 論文集 Vol.25 No.-

The surface and bottom of the water quality in the Asan artificial reservoir have investigated in 6 sites according to the geographycal view points during 3 seasons, summer, autumn and winter. As compared the water quality of two areas near the dike with upper area at 4km distance from dike, it was not found any difference. Vertical variation of water quality was not found certainly difference between the surface and the bottom. Because the depth of this reservoir was no more than 3m, the water temperature was 1℃ high in the surface than bottom in summer, the conductivity increase 7.5μ? high in surface but in autumn and winter the conductivity increase in the bottom especially 12μ? and 13.2μ?. The another items of water quality didn't found any difference. According to the seasonal variation of water quality, the water temperature was 25.6℃ in summer, 17.4℃ in autumn and 4℃ in winter. The concentration of Cl^- was 26.6ppm in summer and gradually increase in autumn and winter especially 103.6ppm and 267.9ppm. The total hardness exhibit much the same tendency with Cl^- and most high in winter as 134.9 ppm. The content of K and Na was lower in summer but most high in winter especially 10.0 ppm and 159.3 ppm. The water quality of the Jin wi river which is one of the water source in this reservoir was severely polluted with industrial waste water. The content of total hardness 152ppm, conductivity 565μ?, the content of COD 6.7ppm, the content of Na 550ppm and the content of Fe 1.4ppm.

세균독소로 자극시킨 사람 섬유아 세포에서의 Interleukin-6와 Interleukin-8의 생성

정인교,양동규,홍시영,이성근,김욱규,김광혁,김종렬 大韓顎顔面成形再建外科學會 1999 Maxillofacial Plastic Reconstructive Surgery Vol.21 No.4

Cytokines are hormone-like proteins which mediate and regulate inflammatory and immune responses. Interleukin-6 (IL-6) is involved in the final differentiation of B cells into antibody-producing cells. Interleukin-8 (IL-8) is a neutrophil chemotactic factor that plays an important role in the recruitment of neutrophil to inflammatory loci. Inflammatory mediators by cells in the gingiva have been implicated in the initiation and progression of periodontitis and oral infection. The purpose of this study was conducted to investigate the effect of lipopolysaccharide (LPS), staphylococcus enterotoxin B (SEB) on production ofIL-6 and IL-8 by human gingival and facial dermal fibroblasts. Primary cultured human gingival and facial dermal fibroblasts were incubated with LPS(0.01, 0.1, 1.0㎍/ml), SEB (0.01, 0.1, 1.0㎍/ml) or LPS (0.1㎍/ml) plus SEB (0.1㎍/ml). Culture supernatants were collected at 24, 48, and 72 hrs and assessed for IL-6 and IL-8 production by enzyme-linked immunosorbent assay. IL-6 production in gingival fibroblasts stimulated with LPS was higher than that with SEB. IL-6 production by double exposure with LPS plus SEB was amplified in comparison with single exposure of LPS or SEB. IL-6 production in facial demal fibroblasts was increased only by stimulation with a high concertration of LPS (1.0㎍/ml). Its production in facial dermal fibroblasts by exposure with SEB was decreased in comparison with control, nontreated cells. Therefore, gingival fibroblasts showed higher sensitivity than facial dermal fibroblasts in response to low concentration of LPS. Also, IL-6 production by double exposure with LPS plus SEB was amplified in comparison with single exposure of LPS or SEB.IL-6 production in facial dermal fibroblasts was increased only by stimulation with a high concentration of LPS(1.0㎍/ml). Its production in facial dermal fibroblasts by exposure with SEB was decreased in comparison with control, nontreated cells. Therefore, gingival fibroblasts showed higher sensitvity than facial dermal fibroblasts in response to low concentration of LPS. Also, IL-6 production by double exposure with LPS plus SEB was amplified in comparison with single exposure of LPS or SEB. IL-8 production in gingival fibroblasts was enhanced greatly only by stimulation of high concentration of LPS (1.0㎍/ml). That by exposure with SEB was increased only in 24 hrs cultivation. IL-8 production by double exposure with LPS plus SEB was amplified in comparison with single exposure of LPS or SEB. IL-8 production in facial dermal fibroblasts was decreased by LPS and increased only in 48 hrs cultivation by SEB. IL-8 production by double exposure with LPS plus SEB was enhanced only in 48 hrs cultivation in comparison with single exposure of LPS or SEB. therefore, IL-6 and IL-8 production were released at various quantities according to bacterial toxin applied and site of fibroblast harvested. These results suggest that gingival fibroblasts may be concerned with IL-6 and IL-8 related inflammatory response more than facial dermal fibroblasts.