축구손상과 예방

김현철,김헝수,Kim Hyun Cheol,Kim Hyung Soo 대한정형외과스포츠의학회 2004 대한정형외과스포츠의학회지 Vol.3 No.1

대중적 구기종목인 축구는 동호회원의 증가로 환자 발생이 많아지는 추세에 있다. 축구에 대한 전반적인 이해를 돕고, 축구 기술의 생체역학적인 면과 손상과의 관계를 고찰하여 예방조치를 취하는데 도움이 되고자 하였다. 실외축구, 풋살, 여자축구 등과 Kick, Pass, Heading 등 기술과 관련된 손상, 특히 최근 논란이 되고 있는 머리부상에 대해서도 문헌고찰 등을 통해 검토하였다. The Football, popular spots in korea, increasing population to participate club activity caused various injuries with the consequence. Investigating relationship between biomechanics of the skills using football and injuries, we propose helpful methods to prevent injuries. Also authors point out the differences between outdoor and indoor football and women's football, and study skills using football like kick, pass, heading and head injury with researching literatures.

Borate 완충용액에서 철의 산화 반응구조와 산화피막의 전기적 특성

김현철,김연규,Kim, Hyun-Chul,Kim, Youn-Kyoo 대한화학회 2012 대한화학회지 Vol.56 No.5

Borate 완충용액에서 Fe의 산화 반응 경로와 생성된 산화피막의 전기적 특성을 조사하였다. Fe는 pH에 의존하는 두 가지의 반응 경로에 의하여 산화되었으며 산화된 피막은 Mott-Schottky 식이 적용되는 n-형 반도체 성질을 가지고 있음을 알 수 있었다. We have investigated the electronic properties of the oxide film and anodic oxidation mechanism. Iron was oxidized by two reaction pathways depending on pH. The oxide film has showed the electronic properties of n-type semiconductor based on the Mott-Schottky equation.

Aging Study with High-Level Radiation Sources for the CMS Forward RPCs

김현철,이경세,Byun Il Kim,홍병식,Chong Kim,D. H. Moon,Duk Gil Koo,E. Won,J. K. Lim,Ji Hyun Kim,Jun Tak Rhee,K. B. Lee,Kwang-Souk Sim,M. S. Ryu,Rong Jiang Hu,S. K. Nam,Sang Yeol Bahk,이석재,Seong Jong Hong,Sung Hw 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.3

An aging study with intensive radiation sources was performed for the forward resistive plate chambers (RPCs) of the Compact Muon Solenoid (CMS) detector in the Large Hadron Collider experiment (LHC). The expected rate of the radiation background to be induced in the forward RPCs ranges from a few tens of Hz/㎠ to as much as ~1 kHz/㎠. Therefore, the radiation hardness for the forward RPCs should be sufficient to ensure the safe operation of the CMS and successful achievement of the LHC physics. Two oil-coated and one plain double-gap RPCs were manufactured and tested with the neutron beam provided by the MC50 cyclotron of the Korea Institute of Radiological and Medical Science (KIRAMS) and with gamma rays from a 200-mCi137Cs source. The estimated radiation dose induced by the fast neutrons was approximately 50 Gy. No significant aging effect was found to be a consequence of the neutron irradiation, However, a degradation of the RPC performance was observed after intense gamma irradiation for a total of 32.5 days. The mean gamma-signal rate drawn in each RPC was 4.0 kHz/㎠, which was approximately two times the maximum rate expected in the highest η-region covering the particle trigger. Increases in the noise rates and the currents accounted for the degradation in the efficiencies for the RPCs. As a result, safe operation of the forward RPCs in the avalanche mode was ensured for signal rates up to 2 kHz/㎠.

내측 안와벽 골절 처치: Transcaruncular approach

김현철,최주석,백진아,신효근,Kim, Hyun-Chul,Choi, Ju-Seok,Baek, Jin-A,Shin, Hyo-Keun 대한악안면성형재건외과학회 2007 Maxillofacial Plastic Reconstructive Surgery Vol.29 No.1

The occurrence of medial orbital wall fracture is isolated or combined with other facial bone fracture. There are many complications, for example, diplopia, enophthalmos, limitation of eye movement, visual activity depression and blindness. Because of these complications, the accurate diagnosis and treatment of medial orbital wall fracture is very important. We have reconstructed medial orbital walls with transcaruncular approach and obtained good results in patients with medial orbital wall fracture.

두부 외상 후 섬망의 자문 정신 의학적 고찰

김현철,이상철,김도훈,이상규,홍승관,손봉기,Kim, Hyon-Chul,Lee, Sang-Chul,Kim, Do-Hoon,Lee, Sang-Kyu,Hong, Seung-Gwan,Son, Bong-Ki 한국정신신체의학회 2004 정신신체의학 Vol.12 No.1

연구목적: 두부 외상은 신체적 후유 증상뿐 아니라 다양한 정신 증상을 야기한다. 본 연구에서는 두부 외상 후 섬망을 보이는 환자들을 대상으로 정신과 자문을 실시하고 과다행동 증상의 유무 등의 임상 양상과 회복 기간과의 관련성에 대해 평가하고자 하였다. 방 법: 1998년부터 2002년까지 두부 외상을 주소로 신경외과에 입원한 환자들 중 섬망이 발생하여 정신과에 자문 조정이 의뢰된 45명의 환자를 대상으로 하였다. 섬망 발생 4주 후 추적 자문에서 섬망의 회복 여부에 따라 완전 관해 된 군 및 잔류 증상이 남아 있는 군으로 나누고, 두 군간의 차이를 과다행동 유무와 사회 인구학적 변수, 두부 외상 부위의 빈도에 따라 살펴보았다. 결 과: 첫 자문 주소에서 과다 행동 유무에 따라 분류해 보았을 때 4주 후의 섬망의 관해와 유의미한 관계를 보였다(p<.01). 섬망의 잔류 증상이 남아 있는 군은 완전 관해 된 군에 비해 중환자실 입원 기간 및(p<.05), 전체 입원 기간이 길었다(p<.01). 섬망 발생 4주 후 잔류 증상이 남아 있는 군은 완전 관해된 군에 비해 사고보험과의 관련성이 많았으며(p<.05), 신경 영상학적 조사에서 피질 하 회백질의 손상의 여부와 유의미한 관계를 보였다(p<.05). 결 론: 본 연구를 통해 첫 자문 의뢰 시 과다행동 유무에 따라 섬망의 회복 기간에 유의한 차이가 있었다. 또한 섬망의 회복 기간이 지연될수록 재원기간이 길어짐을 알 수 있었다. 향후 두부 외상 후 섬망 환자의 정신과적 개입에 있어 과다행동의 유무를 비롯한 임상 변수들에 대한 다각적인 연구가 필요할 것으로 사료된다. Objectives: Delirium after head trauma results in various cognitive and behavioral dysfunction. This study aimed at developing and validating a predicitive model for clinical improvement after delirium based on precipitating factors during hospitalization Method: Data were collected on 45 patients who developed delirium after head trauma using 5 year retrospective design, based on reviews of medical charts including psychiatric consultation reports. The differences of the group who sustained residual symptoms of delirium(The RS group) and the group of full recovery(The FR group) at 4 week follow-up visits were compared by motoric type of delirium, socio-demographic variables, neuroimaging variables and clinical variables of interest. Result: There was significant difference in reason for initial consultation between two groups, in terms of hyperactivity(p<.01). The presence of compensation claim, subcortical gray matter lesion was significantly associated with the RS group(p<.05). Total length of intensive care unit(ICU) admission and of hospital stay were significantly longer in RS group than FR group(p<.01). Conclusion: This study shows that hyperactivity on initial consultation, compensation claims, specific brain lesion were altogether significant factors in explaining prolonged duration of delirium after head trauma. A simple predictive model based on the presence of precipitating factors might be used to identify delirious patients at high risk for prolonged cognitive dysfunction. Early psychiatric intervention would be required for evaluating efficacious management and shortening admission period.

연속주조용 탄소강에서 상변화에 따른 열팽창 및 수축 거동

김현철,이재현,권오덕,임창희,Kim, H.C.,Lee, J.H.,Kwon, O.D.,Yim, C.H. 한국재료학회 2003 한국재료학회지 Vol.13 No.3

The air gap between the metal and mold, formed by shrinkage during solidification, causes surface and subsurface cracks in the continuous casting process. Molten crack on the surface might also occur due to improper heat transfer between them. In order to compensate the air gap in mold design, the thermal contraction is an essential factor. In this study, the thermal contraction and expansion behaviors were examined from the ($\alpha$ and pearlite)/${\gamma}$ to ${\gamma}$/$\delta$ transformations in continuous casting steels by the commercial dilatometer and the self- assembled dilatometer with laser distance measurement. It was found that the thermal contraction and expansion behaviors were very dependant on the phase transformation of the ${\gamma}$/$\delta$ as well as ($\alpha$ and pearlite)/${\gamma}$. The sudden volume change from $\delta$ to ${\gamma}$ which might cause cracks in the continuous casting process, was observed on cooling just below the melting temperature by the self-assembled dilatometer.

비정질 p-SiC/i-SiC/i-Si/n-Si 박막 태양전지에서 i-SiC 완충층의 역할

김현철,신혁재,이재신,Kim, Hyun-Chul,Shin, Hyuck-Jae,Lee, Jae-Shin 한국재료학회 1999 한국재료학회지 Vol.9 No.12

플라즈마 화학증착 (PECVD) 장비를 이용하여 $SnO_2$ 투명전도막이 피막된 유리기판 위에 p-SiC/i-Si/n-Si 이종접합 태양전지를 제작하였다. p-SiC 층의 증착중에 기체조성 x=$CH_4/\;(SiH_4+CH_4)$의 변화에 대한 태양전지의 광기전 특성을 관찰하였다. 기체조성(x)이 0~0.4의 범위에서 p-SiC 창층의 광학적 밴드갭의 증가로 인하여 태양전지의 효율은 증가하였으나, 그 이상의 기체조성에서는 p-SiC/i-Si 계면에서의 조성불일치가 증가하여 태양전지의 효율이 감소하였다. 이러한 계면문제는 p-SiC 층과 i-Si 계면에서의 조성불일치가 증가하여 태양전지의 효율이 감소하였다. 이러한 계면문제는 p-SiC 층과 I-Si 층 사이에 I-SiC 완충층을 삽입함으로써 크게 감소하였다. 그 결과 유효면적이 $1cm^2$인 glass/$SnO_2$/p-SiC/i-SiC/i-Si/n-Si/Ag 구조의 박막 태양전지는 100mW/$cm^2$ 조도 하에서 8.6%의 효율을 나타내었다. ($V_{oc}$=0.85V, $J_{sc}$=16.42mA/$cm^2$, FF=0.615) Thin film solar cells on a glass/$SnO_2$ substrate with p-SiC/i-Si/n-Si heterojunction structures were fabricated using a plasma-enhanced chemical-vapor deposition system. The photovoltaic properties of the solar cells were examined with varying the gas phase composition, x=$CH_4/\;(SiH_4+CH_4)$, during the deposition of the p-SiC layer. In the range of x=0~0.4, the efficiency of solar cell increased because of the increased band gap of the p-SiC window layer. Further increase in the gas phase composition, however, led to a decrease in the cell efficiency probably due to in the increased composition mismatch at the p-SiC/i-Si layers. As a result, the efficiency of a glass/$SnO_2$/p-SiC/i-SiC/i-Si/n-Si/Ag thin film solar cell with $1cm^2$ area was 8.6% ($V_{oc}$=0.85V, $J_{sc}$=16.42mA/$cm^2$, FF=0.615) under 100mW/$cm^2$ light intensity.

Saccharomyces cerevisiae에서 Bacillus CGTase의 표층발현

김현철,임채권,김병우,전숭종,남수완,Kim Hyun-Chul,Lim Chae-Kwon,Kim Byung-Woo,Jeon Sung-Jong,Nam Soo-Wan 한국생명과학회 2005 생명과학회지 Vol.15 No.1

B. stearothermophilus 유래의 CGTase 유전자(cgtS)를 보유하고 있는 재조합 plasmid pCGTS (4.8 kb)을 효모 표면 발현용 vector인 pYDl (GAL1 promoter)에 subcloning 하였다. 구축된 재조합 plasmid, pYDCGT (7.2 kb)는 S. cerevisiae EBY100에 형질전환하였고, tryptophan이 결여된 SD 배지에서 1차 선별된 형질전환체들을 YPGS배지에서 배양 후 활성 염색을 통하여 CD가 생 성 됨을 확인하였다. 배양시간과 효소반응시간에 따른 반응 산물을 TLC로 분석 한 결과, 배양 12시간째부터 효소활성이 나타났고, 반응 10분 이후부터 CD가 생성되어 시간이 지남에 따라 CD 생성양이 증가하는 것을 확인하였다. 회분 배양한 결과 $25^{\circ}C$와 $30^{\circ}C$에서 CGTase의 최대 활성이 각각 21.3 unit/1 와 16.5 unit/1로 나타났고, plasmid 안정성은 각각 $86\%$와 $82\%$로 나타나 배양온도에 상관없이 plasmid는 비교적 안정하게 유지되었다. For the expression in Saccharomyces cerevisiae, Bacillus stearothermophilus cyclodextrin glucano­transferase gene (cgtS) in pCGTS (4.8 kb) was subcloned into the surface expression vector, pYD1 (GALl promoter). The constructed plasmid, pYDCGT (7.2 kb) was introduced into S. cerevisiae EBY100 cells, and then yeast transformants were selected on the synthetic defined media lacking tryptophan. The formation of cyclodextrin (CD) was confirmed with active staining of culture broth of transformant grown on starch medium. Enzymatic reaction products with respect to the culture time and the reaction time were examined by TLC analysis. The results indicated that the enzyme activity was exhibited after 12 h cultivation and CD was produced after 10min of enzymatic reaction. When the surface-engineered yeast cells were cultured on galactose medium, maximum activities of CGTase were about 21.3 unit/l and 16.5 unit/l at $25^{\circ}C\;and\;30^{\circ}C$, respectively. The plasmids stability showed about $80\%\;even\;at\;25^{\circ}C\;and\;30^{\circ}C$.

광역경제권과 지역 경쟁력

김현철,Kim, Hyeon-Cheol 대전발전연구원 2008 대전발전포럼 Vol.28 No.-

플라즈마 화학증착법으로 제조된 B-doped a-SiC:H 박막의 물성

김현철,신혁재,이재신,Kim, Hyeon-Cheol,Sin, Hyeok-Jae,Lee, Jae-Shin 한국재료학회 1999 한국재료학회지 Vol.9 No.10

$SiH_4$, $CH_4$, $B_2H_6$ 혼합기체를 이용하여 플라즈마 화학증착법으로 탄화실리콘 (a-SiC:H) 박막을 증착하였다. 증착중에 혼합기체중의$CH_4$농도 ($CH_4/CH_4+SiH_4$)를 변화시켜 얻은 박막의 물성을 SEM, XRD, Raman 분광법, FTIR, XPS, 광흡수도와 광전도도 분석을 통하여 살펴보았다. $SiH_4$기체만 이용하여 증착한 Si:H 박막은 비정질상태를 나타내었으나, $CH_4$가 첨가됨에 따라 실리콘 박막의 Si-$\textrm{H}_{n}$(n은 정수) 결합기가 Si-$\textrm{C}_{n}\textrm{H}_{m}$ (n,m은 정수) 형태의 결합기로 변화되었으며, 박막내 수소함량은 $CH_4$농도가 0~0.8의 범위에서 증가함에 따라 30~45% 범위에서 증가하였다. 반응기체중의 $CH_4$농도의 증가에 따라 박막 내의 탄소 농도가 증가함을 확인하였으며, 이에 따라 막의 전기비저항과 광학적밴드갭 역시 증가하였다. B-doped hydrogenated amorphous silicon carbide (a-SiC:H) thin films were prepared by plasma-enhanced chemical-vapor deposition in a gas mixture of $SiH_4$, $CH_4$ and $B_2H_6$. Microstructures and chemical properties of a-SiC:H films grown with varing the volume ratio of $CH_4$ to $SiH_4$ were characterized with various analysis methods including scanning electron microscopy(SEM), X-ray diffractometry(XRD), Raman spectroscopy, Fourier-transform infrared (FTIR) spectroscopy. X-ray photoelectron spectroscopy(XPS), UV absorption spectroscopy and photoconductivity measurements. While Si:H films grown without $CH_4$ showed amorphous state, the addition of $CH_4$ during deposition enhanced the development of a microcrystalline phase. By introducing C atoms into the film, Si-Si and Si--$\textrm{H}_{n}$ bonds of a -Si:H films were gradually replaced by Si-C, C-C, and Si--$\textrm{C}_{n}\textrm{H}_{m}$ bonds. Consequently, the electrical resistivity and optical bandgap of a-SiC:H films were increased with the C concentration in the film.