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.

계태에서의 31P 자기공명분석법을 이용한 인대사변화의 추적

홍창의,임태환,이정희,이대근,유시준 울산대학교 의과대학 1994 울산의대학술지 Vol.3 No.2

Chick embryo is a convenient model for embryologic teratologic studies. We performed the present experimental study to establish the basic technology for magnetic resonance studies of chick embryos and to examine the biochemical changes occurring during the development of chick embryos. Fertilized Leghorn eggs were examined by 31-phosphours magnetic resonance spectroscopy (??P-MRS) on days 6, 9, 12, 14, 15, 17 and 20 after the start of incubation. Spectroscopic data of live embryos were acquired by using a 4.7T MR spectrometer, and signals from phosphorous metabolites were analyzed. Total phospholipid signal decreased, which resulted in the overall decrease in total phosphorous signal over time. Signals from other metabolites such as ATPs and phosphocreatine increased over time, while those from inorganic phosphate and sugar phosphates decreased. Before the incubation days 12, signals from sugar phosphates and inorganic phosphate were predominant, and other metabolites became remarkably functional between the days 12 and 14 when the decrease in the phospholipid signal was significant. MR specrtroscopy is an effective method in evaluation of the biochemical changes occurring during the developmental period of chick embryos.

이동형 생체계측을 위한 임베디드 컴퓨팅

홍주현,진계환,박경순,조명찬,박길선,차은종,이태수 충북대학교 의과대학 충북대학교 의학연구소 2003 忠北醫大學術誌 Vol.13 No.2

연구목적: 초소형 정밀 기계 기술로 제작된 2차원 가속도 센서와 916 MH2 단거리 고주파 데이터 통신 기술을 응용하여 인체의 운동상태를 자동으로 감지하고 분류하는 기법을 제안 하고자 하였다. 재료 및 방법: 인체의 신호를 획득하기 위하여 미국 버클리대에서 제작한 무선 센서를 등 산용 조끼의 전면상단에 부착해서, 대상자의 흉골 부위에 위치하도록 하고, 앉은 상태에서 일어서거나 눕거나 하는 동작 및 그 역동작이 일어날 때, 가속도 센서에서 감지되는 4가지 종류의 파형 현화에 해당되는 데이터를 무선센서 네트웍을 통해 획득하였다. 결과: 획득한 신호를 주성분분석(Principal Component Analysis)과 지원벡터머신(Support Vector Machine)을 사용하여, 2차주성분까지를 도표화하고 클러스터링 함으로써, 4개의 영역으로 분할하는 것이 가능함을 말 수 있었다 결론: 소형 센서들이 작동되는 임베디드 컴퓨팅 환경에서 일상생활 중에 발생하는 인체의 4가지 동작을 자동으로 감지하고 분류하는 것이 가능함을 보였다. Purpose: New monitoring and classifying method of human motion contort was pro- posed by using 2-axial MEMS accelerometer and 916 MHz short-range data communica-tion technology. Materials and Methods: The wireless sensor of MICA mote was attached to a woman mountain vest and located close to the subject's sternum. During four types of sub-ject's motion, that is, sit-to-stand, stand-to-sit, sit-to-tying, and tying-to-sit, waveform changes of the accelerometer data were acquired by wireless sensor network. Results: The acquired signal was analyzed by Principal Component Analysis(PCA) and Support Vector Machine(SVM) technique. By clustering the first and second principal components, four regions corresponding to the four types of motion, were clearly segment-ed. Conclusion: Human motion context during daily life could be monitored and classified automatically by using small sensors in embedded computing environment

무증상으로 발견된 담낭-담관 누공을 동반한 Mirizzi 증후군 1예

홍진희,전태주,서지영,서동대,오태훈,신원창,최원충,신은아,김기환 인제대학교 2009 仁濟醫學 Vol.30 No.-

Mirizzi's syndrome is a rare complication of the gallstone disease, characterized by narrowing of the common bile duct (CBD) due to chronic extrinsic compression of an impacted gallstone in the cystic duct or the neck of the gallbladder. The impacted gallstone may erode into the bile duct, causing cholecystocholedochal fistula. The patients generally have history of repeated attacks of jaundice and abdominal pain. But there is no report about asymptomatic Mirizzi syndrome with cholecystocholedochal fistula which were found incidentally. So herein we present our clinical experience with a case of asymptomatic Mirizzi syndrome with cholecystocholedochal fistula in a young female.

임플란트 주위 조직 보존을 위한 임플란트 경부의 디자인에 관한 고찰

김홍준,김지환,김성태,이재훈,박영범 大韓齒科保存學會 2011 Restorative Dentistry & Endodontics Vol.36 No.6

연구 목적: 임플란트 식립 후 변연골 흡수에 따라 임플란트 주위 연조직이 재구성되며, 이에 따라 치료의 예후 및 심미성 등에 영향을 주게 된다. 그러므로 임플란트 경부 주위 골조직 보존을 위한 임플란트 경부에 다양한 디자인이 연구되고 있다. 본 고찰의 목적은 초기 변연골 흡수의 원인과 이에 따른 임플란트 주위의 연조직 변화에 대해 고찰하고, 어떠한 임플란트 경부 디자인이 임플란트 주위 조직의 보존에 유리한 지 알아보고자 한다. 연구 재료 및 방법: Pubmed database에서 임플란트 초기 변연골 흡수의 원인과 관련된 논문과 임플란트 경부의 여러 디자인에 관한 논문을 검색하여 분석하였다. 임플란트 경부 디자인은 one piece implant, two piece implant, internal hex abutment, external hex abutment, taper joint connection, butt joint connection, scalloped design abutment, platform switching concept에 관해 검토하였다. 결과: 초기의 임플란트 주위 조직 보존에 대하여 one piece implant가 two piece implant보다 유리한 것으로 여러 임상적, 실험적 연구가 있다. Two piece implant에서는 internal hex abutment가 external hex abutment보다, taper joint connection가 butt joint connection보다 유리할 것으로 보여진다. Scalloped design abutment에 대해서는 논쟁의 여지가 있어 더 많은 연구가 필요할 것으로 판단된다. Platform switching concept은 그 원인이 명확히 밝혀지지는 않았으나 임상적, 실험적으로 초기 임플란트 주위 조직 보존에 대해 유리한 것으로 판단된다. 결론: 임플란트 경부의 디자인마다 각각의 장단점이 있고 추가적인 연구가 더 필요한 제한이 있지만 현재까지의 선행 연구들을 분석 종합해 보면 초기 임플란트 주위 조직 보존을 고려한다면 가능한 경우 one piece implant가 유리할 것으로 판단되며, 보철적인 문제나 다른 이유로 인하여 two piece implant를 고려할 경우 platform switching concept, internal connection abutment, taper joint connection을 이용하는 것이 임플란트 주위 조직 보존에 좀더 유리할 것으로 사료된다 Purpose: The peri-implant soft tissue is remodeled by the initial marginal bone resorption affecting the prognosis and esthetic result of treatment. Thus various designs on implant neck design are studied to preserve peri-implant bone. The purpose of this study is to review on the causes of initial marginal bone resorption, the configuration of peri-implant soft tissue, and the implant crestal module favorable in preserving peri-implant tissue. Materials and methods: The studies on the causes of initial marginal bone resorption and the implant crestal modules are researched and reviewed using Pubmed database. The implant crestal modules including one piece and two-piece implant, internal and external hex abutment, taper and butt joint connection, scalloped design abutment, and platform switching concept are reviewed. Results: A number of clinical and experimental studies preferred one piece implant to two-piece in preserving initial peri-implant tissue. For two piece implants, internal hex abutment and taper joint connection appear more favorable than external hex abutment and butt joint connection relatively. Controversial issues still exist on scalloped design requiring more studies on it. Although the rationale is not certain, the concept of platform switching seems favorable in preserving initial peri-implant tissue based on clinical and experimental studies. Conclusion: Each implant crestal module contains its own advantages and disadvantages with various controversial issues. In the aspect of preservation of initial peri-implant tissue, however, one-piece implant seems beneficial. In cases when two-piece implant is more appropriate due to prosthodontic concerns or any other problems, the application of platform switching concept, internal connection abutment, and taper joint connection may be favorable for the preservation of peri-implant tissues.

전자공학교육과 실험교과내용에 관한 연구

홍봉식,김태균,오승엽,김환우,권오석 충남대학교 공업교육연구소 1983 論文集 Vol.6 No.2(A)

The currenty offered experiment courses are completely reconsidered and reconfigured. The whole subjects are divided into 10 seperate courses, each of which should represent either basic or advanced stages of differing fields of the electronic engineering. It has been aimed that the courses form an elaborate hierachy so that they are minimally redundant but linked to one another in their fringes. Also, it has been pursued that the new courses should not fall obsolete in at last next five years exploring the maximum possibilities of the currently available equipments.

H₂- CO₂중에서 FeAl₂O₄의 생성기구와 CO₂중에서의 거동(II)

이홍림,정태환 연세대학교 산업기술연구소 1983 논문집 Vol.15 No.2

Fe₂O₃and Al₂O₃powders were mixed in molar ratio of Fe₂O₃/Al₂O₃= 1/2, and to these mixtures MgO powder was added 1,3,5,10,15,20 in weight %, respectively. The mixtures were pressed into pellets of 14mmΦ×14mm after well mixed in wet process using acetone. The pelletized specimens were heated at 1300℃ for 2 hours in air and again heated at 1200℃ for 5 hours in H₂- CO₂(H₂/CO₂=1/1) mixture before subjected to measurement of their electrical conductivities, compressive strengths, X-ray diffraction analyses etc. These specimens were again heated at 1200℃ for 5 hours in CO₂and their X-ray diffraction analyses and physical properties measurements were also conducted. Electrical conductivities, compressive strengths and other properties of the specimens were enhanced according to addition of MgO.

사비의 교정에 있어서 내시경의 이용

박대환,김태모,이재욱,송철홍,한동길,안기영 大韓成形外科學會 1998 Archives of Plastic Surgery Vol.25 No.1

Owing to the complexity of the deviated structures and the septal deformities accompanying the external nasal deformities, the complete correction of the deviated nose is regarded as a difficult one. The approach to the nasal bone and osteotomy in classic corrective rhinoplasty is almost blind technique, where the results depends on the feeling by surgeon's hand. To overcome these drawback, endoscopic-assisted corrective rhinoplasty and septoplasty performed for 8 cases of deviated nose between January 1996 and May 1997. Average follow-up period was 10 months. All patients were evaluated by symmetrical nasal pyramid, recurrence of the bony deflection and septal deviation. The postoperative courses were satisfactory in most of cases with few complications. It appears that endoscopic control during corrective rhinoplasty and septoplasty is a big step toward obtaining better results in bony and cartilage resection with extreme precision under monitor control and magnification. This technique is not an open approach but permits one to see more of the nasal skeleton and bony septum what is causing deformity, and the immediate effect of the corrective measures used. The use of endoscope in corrective rhinoplasty will provide expanded field of vision, direct manipulation of lesions, and better aesthetic an6 functional results.

저수지에서의 수질의 동향

김을환,양태홍,이영자,최한영 서울保健大學 1990 論文集 Vol.10 No.1

This study was performed to investigate the content of a few inorganic metals and the degree of water temperature pH, DO, BOD, COD, SS, TH, Cl^(-), SO_(4)^(-), total alkali and PO_(4)^(3)-P in Singal Lake. In general they are favorable as the water to see but compared with the several terms which are measured in 1976 the pollution of the water increased by five or six times.

의료용 생체재료의 팽윤과 표면성질에 관한 연구

김을환,양태홍,이영자 서울保健大學 1986 論文集 Vol.6 No.1