Effect of the Applied Bias Voltage on the Formation of Vertically Well-Aligned Carbon Nanotubes

김성훈,Kim, Sung-Hoon Materials Research Society of Korea 2003 한국재료학회지 Vol.13 No.7

Carbon nanotubes were formed on silicon substrate using microwave plasma-enhanced chemical vapor deposition method. The possibility of carbon nanotubes formation was related to the thickness of nickel catalyst. The growth behavior of carbon nanotubes under the identical thickness of nickel catalyst was strongly dependent on the magnitude of the applied bias voltage. High negative bias voltage (-400 V) gave the vertically well-aligned carbon nanotubes. The vertically well-aligned carbon nanotubes have the multi-walled structure with nickel catalyst at the end position of the nanotubes.

IPS Empress 도재관의 파절강도: 하악 제1대구치에서 교합면 두께와 축면경사도에 따른 영향

김성훈,이진한,김유리,동진근,Kim Sung-Hoon,Lee Jin-Han,Kim Yu-Lee,Dong Jin-Keun 대한치과보철학회 2003 대한치과보철학회지 Vol.41 No.1

The purpose of this study was to compare the fracture strength of the IPS Empress ceramic crown according to the occlusal depth (1.5mm, 2.0mm, 2.5mm) and axial inclination ($4^{\circ},\;8^{\circ},\;12^{\circ}$) of the lower First Molar. After 10 metal dies were made for each group, the IPS Empress ceramic crowns were fabricated and cemented with resin cement(Bistite resin cement, Tokuyama Soda Co. LTD., Japan). The cemented crowns were mounted on the testing jig with inclination of 30 degrees and the universal testing machine(Zwick Z020, Zwick, Germany)was used to measure the fracture strength. The results of this study were as follows : 1. The fracture strength of the ceramic crown with 2.5mm depth and $12^{\circ}$ inclination was the highest (1789 N). Crowns of 1.5mm depth and $4^{\circ}$ inclination had the lowest strength (1091 N). 2. There were no significant differences in the fracture strength by axial inclination of the same occlusal depth group. 3. Most fracture lines began at the loading area and extended through proximal surface perpendicular to the margin, irrespective of occlusal depth. Size of fragment was affected by the amount of occlusal reduction.

저압 화학 기상 증착 조건에서 Si$H_4$, W$F_6$ 환원 반응에 의한 텅스텐 박막의 성장 양식

김성훈,Kim, Sung Hoon 한국결정성장학회 1993 한국결정성장학회지 Vol.3 No.2

LPCVD 조건하에서 Si 기판을 이용하여 W$F_6$를 환원시키거나 Si$H_4$를 이용하여 W$F_6$를 환원시켜 Si(100) 기판위에 텅스텐 박막을 증착하였다. 증착된 박막들의 표면 및 단면 형상과 특성들을 조사하였으며 박막들의 결정구조는 체심입방구조를 이루는${alpha}$-W임을 알수 있었다. 박막내의 텅스텐의 양과 grain들의 크기는 박막이 성장함에 따라 증가하였다. 실험적인 결과와 이론적인 고찰들로부터 텅스텐 박막은 Volmer-Weber 성장양식인 island growth를 이룸을 알 수 있었고 세부적인 박막 성장양식을 제시하였다. 또한 텅스텐 박막이 성장할수록 박막의 결정구조는 점점 단결정화 하여감을 알수 있었다. Tungsten thin film was deposited on Si( 100) substrate by either Si substrate reduction of W$F_6$( case 1) or Si$H_4$ reduction of W$F_6$( case 2) in LPCVD system The morphology and properties of deposited films for both cases were examined. The crystal structure for both cases was determined to be bec (body centered cubic). The amount of tungsten and the grain size in thin films were increased as the film grows. From the experimental results and theoretical considerations, it can be understood that the tungsten thin film grows by the volmer-weber growth mode, that is, island growth. The detailed tungsten thin film growth mode is presented. It was also found that the initial polycrystal structure of tungsten thin film developed into single crystal structure as the film grew in thickness.

삼차신경통에 대한 미세혈관감압술의 효과

김성훈,최창화,Kim, Sung-Hoon,Choi, Chang-Hwa 대한신경외과학회 2005 Journal of Korean neurosurgical society Vol.37 No.5

Objective: The microvascular decompression(MVD) for trigeminal neuralgia(TN) is known as an effective surgical technique. But the failed MVD cases have been reported in long term follow-up studies. This study is to evaluate the efficacy of MVD through our operative techniques, offending vessels in operative field, failed cases with the review of the literatures. Methods: We analyzed total 63 cases of TN which underwent MVD from 1955 to 2003 according to characters of pain, operative findings, operative results related to causative vessel compression and operative method, progonotic factor. Statistical analysis was performed using paired t-test with SPSS Ver 11.0. Results: In TN, the most common offending vessel was superior cerebellar artery(45.0%). In compression group of nerve root by offending vessel, the cure rate was 91.7%. However, the cure rate of the contact group was 64.7% and the cure rate of the negative group was 37.5%. There was no statistical significance between the degree of compression by vessel and the operative result(p=0.076). In 51 cases with MVD only, the cure rate was 84.3% and in 3 cases with PSR only, 42.8% and in 2 cases with PSR(partial sensory rhizotomy) with MVD, 50.0%. TN recurred in 7 cases within the follow-up period and reoperations(PSR) were added in 2 cases of them. Conclusion: This study shows that MVD provided a high rate of success with a minor risk of complications, which has been regarded as the most safe and effective procedure for trigeminal neuralgia. Additional MVD in recurred TN by severe adhesion of teflon showed poor outcome. But, revisional operation(PSR) in recurred TN showed relatively good outcome. PSR should be considered for treatment of recurrent TN after MVD.

발효 , 세포배양 , 생물공정 잔나비 걸상 버섯 자실체 및 균사체의 생리활성 탐색

김성훈,이주노,김선희,오세종,안상욱,이진하,박영식,정을권,이현용 ( Sung Hoon Kim,Ju No Lee,Sun Hee Kim,Se Jong Oh,Sang Wook An,Jin Ha Lee,Young Shik Park,Eul Kwon Chung,Hyeon Yong Lee ) 한국미생물생명공학회 1998 한국미생물·생명공학회지 Vol.26 No.4

The effect of captafol on the hematological value, erythrocyte membrane and plasma biochemical value in vitro

김성훈,황화선,차신우,한상섭,노정구,Kim, Sung-hoon,Hwang, Hwa-seon,Cha, Shin-woo,Han, Sang-seop,Roh, Jung-koo The Korean Society of Veterinary Science 1993 大韓獸醫學會誌 Vol.33 No.3

Captafol은 phthalimide계통의 항진균제로써 difolatan이란 상품명으로 개발되어 과일, 채소의 탄저병 및 원목 등의 곰팡이 구제에 널리 사용되고 있는 것으로 국내에서도 두번째로 많이 생산, 사용되는 품목이나 독성실험에 관한 보고는 거의 없는 상태이다. 이에 본 연구에서는 captafol 자체에 대한 독성기전의 일부를 확인하고자 동물체내에서 일어나는 여러가지 대사작용이 배제된 시험관내에서 실험을 수행하였다. 랫트 혈액을 후대정맥으로 부터 채혈하여 4개의 시험관에 $2.5m{\ell}$씩 분주한 후 captafol 농도가 $0.1{\times}10^{-4}M$, $1{\times}10^{-3}M$, $1{\times}10^{-2}M$이 되도록 한 ethanol용액 $25{\mu}{\ell}$씩 넣고 $CO_2$ incubator에서 2시간 동안 부드럽게 혼합하여 혈액학적 성상 및 적혈구 취약성 시험을 수행하였다. 또한 원심분리하여 얻어진 혈장에서 생화학적 성상 등을 조사한 결과 다음과 같은 성적을 얻었다. 1. 적혈구수 및 hematocrit치는 captafol 투여량에 비례적으로 유의한(p<0.05) 감소를 나타내었다. 2. 적혈구막 취약성 실험에서 $1{\times}10^{-3}M$ 및 $1{\times}10^{-2}M$ 농도에서 대조군에 비하여 유의한(p<0.01) 증가를 나타내었다. 3. 혈장내 potassium이온의 농도는 captafol의 투여량에 비례적으로 증가하였다. 4. Total bilirubin 및 creatine kinase가 대조군에 비하여 각각 증가 및 감소하였다. The effect of captafol on the hematological value, erythrocyte membrane and plasma biochemical value was investigated using blood of SPF Sprague-Dawley male rats in vitro. For the anticoagulations, we used 0.5mg of heparin per $10m{\ell}$ of blood from vena cava. Three con-centrations($0.1{\times}10^{-4}M$, $1{\times}10^{-3}M$ and $1{\times}10^{-2}M$) captafol in ethanol were added to the each $2.5m{\ell}$ blood so that the linal concentration of ethanol was 1%. The blood contained with each concentration of captafol was incubated at $37^{\circ}C$ C for 2 hours under 5% $CO_2$ gas The whole blood and plasma were examined for hematological vaJues, erythrocyte membrane damage and biochemical values, respectively. The results obtained were summarized as follows ; 1. The number of RBC in $1{\times}10^{-2}M$ group and the concentration of MCHC in $1{\times}10^{-3}M$ group were significantly (p<0.05) decreased and increased from that of control values, respectively. The percentage of Hct was significantly (p<0.05) decreased with dose-response. 2. Erythrocyte fragility rate of $1{\times}10^{-3}M$ and $1{\times}10^{-2}M$ group were significantly (p<0.01) increased from that control with dose response. 3. Potassium ion level of $1{\times}10^{-2}M$ was significantly (p<0.05) increased from that of control. 4. The concentration of total bilirubin in the $1{\times}10^{-3}M$ and $1{\times}10^{-2}M$ groups were significantly increased from that of control. The enzyme level of creatine kinase in $1{\times}10^{-2}M$ group was significanlty (p<0.05) decreased from control value.

철분투여가 흰쥐의 간장 , 비장 및 근육조직내 지질함량에 미치는 영향

김성훈,허인수,박항균,모기철,김영홍 ( Sung Hoon Kim,Rhin Sou Huh,Hang Kyun Park,Ki Choul Mo,Young Hong Kim ) 한국축산학회 1985 한국축산학회지 Vol.27 No.11

The purposes of the present studies were to clarify the effect of iron on the contents of the total free fatty acids, free unsaturated fatty acids, phospholipids, and unsaturated fatty acids in phospholipids in the liver, spleen, and muscle tissues of rats. Twenty rats were devided into 4 groups each consisting of 5 rats. A group was fed a control diet, B group was fed the same control diet and administered 3m1 of 1.5%Fe(OH)3 by intramuscular injection per week, C group was fed the control diet containing 2.5%Fe(OH)₃, and D group was fed the control diet supplemented with 5% of Fe(OH)3 for 60 days. The results obtained were summarized as follows: 1. Mean total free fatty acid concentrations is the liver, spleen and muscle tissues of A, B, C and D groups were 5.496, 5.570, 3.626㎎/g, 6.910, 5.938, 3.632㎎/g, 5.806, 5.076, 4.108㎎/g, and 7.462, 6.020, 4.330㎎/g, respectively. 2. Mean free unsaturated fatty acid concentrations in liver, spleen and muscle tissues of A, B, C and D groups were 2.202, 2,612, 1.860 ㎎/g, 2.676, 2.180, 1.936 ㎎/g, 2.418, 1.922, 1.894 ㎎/g, and 2.786, 1.950, 1.988 ㎎/g, respectively. 3. Mean phospholipid concentrations in liver, spleen and muscle tissues of A, B, C and D groups were 33.60, 30.56, 15.62 ㎎/g, 24.70, 29.32, 13.82 ㎎/g, 26.30, 29.16, 14.46 ㎎/g, and 24.54, 27.20, 13,24 ㎎/g, respectively. 4. Mean unsaturated fatty acid concentrations in phospholipids in liver, spleen and muscle tissues of A, B, C and D groups were 1.704, 1.364, 0.746 ㎎/g, 1.594, 1.316, 0.738 ㎎/g, 1.61, 1.32, 0.726 ㎎/g, and 1.188, 1.280, 0.648 ㎎/g, respectively.

주조 포스트의 유지력에 관한 연구

김성훈,조혜원,진태호,Kim Sung-Hoon,Cho Hye-Won,Jin Tai-Ho 대한치과보철학회 1993 대한치과보철학회지 Vol.31 No.4

The purpose of this study was to evaluate the effects of method for construction of cast post and type of dental cement on the retention of cast post. The wax patterns or Duralay resin patterns were used for construction of cast post. The dental cements used in this study were zinc phosphate cement(Fleck's zinc cement, Mizzy INc., U.S.A.), glass ionomer cement(Fuji I, G-C Co., Japan), and resin cement(Panavia-EX, Kuraray Co., Japan) and the retention of cast post was measured with Instron Universal Test Machine(Instron Engineering Co., U.S.A.). The obtained results were as follows : 1. The tensile bond strength of cast posts made by Duralay resin patterns revealed 39.13(kg) with Panavia-EX, 46.40(kg) with phosphate cement, and 37.78(kg) with glass ionomer cement. 2. The tensile bond strength of cast posts made by wax patterns revealed 39.25(kg) with Panavia, EX, 44.12(kg) with phosphate cement, and 40.23(kg) with glass ionomer cement. 3. The tensile bond strength of cast posts made by Duralay resin patterns or wax patterns were not affected by the type of dental cements(P>0.05).

SONET 통신 시스템을 위한 $8{\sim}10.9$ GHz 저 위상 잡음과 넓은 튜닝 범위를 갖는 새로운 구조의 LC VCO 설계

김성훈,조효문,조상복,Kim, Seung-Hoon,Cho, Hyo-Moon,Cho, Sang-Bock 대한전자공학회 2008 電子工學會論文誌-SD (Semiconductor and devices) Vol.45 No.1

In this paper, New LC VCO with $8{\sim}10.9$ GHz Band has been designed using commercial $0.35-{\mu}m$ CMOS technology. This proposed circuit is consisted of the parallel construction of the typical NMOS and PMOS cross-coupled pair which is based on the LC tank, MOS cross-coupled pair which has same tail current of complementary NMOS and PMOS, and output buffer. The designed LC VCO, which is according to proposed structure in this paper, takes a 29% improvement of the wide tuning range as 8 GHz to 10.9 GHz, and a 6.48mW of low power dissipation. Its core size is $270{\mu}m{\times}340{\mu}m$ and its phase noise is as -117dBc Hz and -137dBc Hz at 1-MHz and 10-MHz offset, respectively. FOM of the new proposed LC VCO gets -189dBc/Hz at a 1-MHz offset from a 10GHz center frequency. This design is very useful for the 10Gb/s clock generator and data recovery integrated circuit(IC) and SONET communication applications. 본 논문에서는 $0.35-{\mu}m$ CMOS 공정을 이용 $8{\sim}10.9$ GHz 밴드를 갖는 새로운 구조의 LC VCO를 설계 제안하였다. 이 회로 구성은 LC 탱크 기반의 전형적인 NMOS, PMOS cross-coupled 쌍을 병렬로 구성한 새로운 구조로 상보적인 NMOS와 PMOS 꼬리 전류와 같은 MOS cross-coupled쌍과 출력 버퍼로 구성하였다. 본 논문에서 제시한 구조로 설계된 LC VCO는 8GHz에서 10.9GHz까지로 29%의 증가된 튜닝 범위와 6.48mV의 낮은 전력소모를 가지는 것을 확인하였고 이의 core size는 $270{\mu}m{\times}340{\mu}m$, 시뮬레이션을 통한 VCO의 위상잡음은 1MHz와 10MHz offset에서 각각 -117dBc/Hz와 -137dBc/Hz이다. FOM은 10GHz의 중심 주파수으로 부터 1MHz offset에서 -189dBc/Hz를 가진다. 제안한 설계방법은 10Gb/s급의 클럭과 데이터 복원회로 그리고 SONET 통신응용에 매우 유용하다.

LDPC 부호화를 위한 효율적 알고리즘

김성훈,이문호,Kim, Sung-Hoon,Lee, Moon-Ho 대한전자공학회 2008 電子工學會論文誌-TC (Telecommunications) Vol.45 No.2

Although we can make a sparse matrices for LDPC codes, the encoding complexity per a block increases quadratically by $n^2$. We propose modified PEG algorithm using PEG algorithm having a large girth by establishing edges or connections between symbol and check nodes in an edge-by-edge manner. M-PEG construct parity check matrices. So we propose parity check matrices H form a dual-diagonal matrices that can construct a more efficient decoder using a M-PEG(modified Progressive Edge Growth). LDPC 구조는 1개의 개수가 적은 구조의 패리티 체크 행렬을 구성하여도, H행렬의 역행렬을 구하는 과정 중에 가우시안 소거법으로 인하여 H 행렬은 1의 개수가 적은 성질이 없어지고 계산량도 블록 크기 당 $n^2$의 계산량이 요구되어지고 있다. 그러므로 LDPC 패리티 체크 행려인 H는 좀 더 효율적인 부호화에 초점을 두고 개발되고 있다. 본 논문에서는 edge-by-edge 방법으로 체크 노드와 심볼 노드사이를 연결하거나 연결선을 정하는 것으로 큰 girth를 가지는 Tanner 그래프를 구성할 수 있는 PEG 알고리즘을 변형 시킨 M-PEG를 패리티 체크 행렬인 H를 구성하고 좀 더 효율적으로 부호화기를 구성할 수 있도록 dual-diagonal 형태를 지니는 H를 구성한다.