Rheological response to microstructural transition: an example from granitic rocks in the Yecheon shear zone

( Seung Hak Yoo ),( Young Do Park ),( Jin Han Ree ) 대한지질공학회 2002 대한지질공학회 학술발표회논문집 Vol.2002 No.1

골화석증 환자에서 발생한 무지 외반증 치험예

차승도(Seung Do Cha),김형수(Hyung Soo Kim),유정현(Jeong Hyun Yoo),박재형(Jai Hyung Park),김주학(Joo Hak Kim),조주원(Joo Won Joh) 대한정형외과학회 2008 대한정형외과학회지 Vol.43 No.6

골 화석증은 발생 빈도가 극히 낮은 골격계 유전성 질환으로 장관골의 골절에 대한 논문만이 간혹 보고되고 있고 대부분 보존적 방법으로 치료를 하며 수술시 어려운 점이 많은 것으로 알려져 있다. 특히 골 화석증 환자에서 발생되는 무지 외반증은 중증인 경우가 대부분이며 치료에 대해서 언급한 논문은 거의 없는 실정이다. 저자는 골 화석증 환자의 중증 무지 외반증을 삼중 절골술로 치료하여 불유합과 중족-족지 관절의 아탈구, 나사못의 파손 등의 만족스럽지 못한 결과를 경험하여 국내에서는 최초로 문헌 고찰과 함께 그 치료 경험을 보고하는 바이다. Osteopetrosis is a very rare hereditary musculoskeletal disorder with an unknown cause. There are few reports on this condition with most focusing on long bone fractures. Most patients with osteopetrosis require non-surgical treatment and surgery is technically difficult. Hallux valgus deformities in patients with osteopetrosis are always severe and there are no reports on its treatment. We treated a hallux valgus deformity using triple osteotomy method and experienced nonunion, subluxation of the first metatar-sophalangeal joint and screw breakage. This is the first report of the surgical treatment of such a case in Korea. We report this case with a review of the relevant literature.

The doping mechanism and electrical performance of polyethylenimine‐doped MoS­₂ transistor

Hong, Seongin,Yoo, Geonwook,Kim, Dong Hak,Song, Won Geun,Le, Ong Kim,Hong, Young Ki,Takahashi, Kaito,Omkaram, Inturu,Son, Do Ngoc,Kim, Sunkook WILEY‐VCH Verlag Berlin GmbH 2017 Physica status solidi. PSS. C, Current topics in s Vol.14 No.3

<P>Seongin Hong et al. (article no. <url href='http://doi.wiley.com/10.1002/pssc.201600262'>1600262</url>) have investigated the polyethylenimine (PEI) doping mechanism and its effect on the electrical and optical properties of multilayer MoS<SUB>2</SUB> field effect transistors (FETs). Density functional theory (DFT) calculation and X‐ray photoelectron spectroscopy (XPS) measurement confirm that the PEI molecules were successfully doped and formed Mo–N bonds on the MoS<SUB>2</SUB> channel, generating new energy states near the valence band. The strong n‐doping changed the threshold voltage as well as the Schottky barrier width attributed to the induced interfacial dipoles. Therefore, the ON‐current of the doped MoS<SUB>2</SUB> FETs was improved in comparison with the pristine FETs. Furthermore, the PEI doping also enhanced the photoresponsivity of the MoS<SUB>2</SUB> FETs from 0.14 A/W to 4.41 A/W. This study suggests that PEI molecular doping could be widely applicable to two‐dimensional materials in order to improve the electrical and optical properties of respective devices.</P>

태권도 선수에서 발생된 장무지 신전건 기능 부전의 치험 예

차승도 ( Seung Do Cha ),김형수 ( Hyung Soo Kim ),정수태 ( Soo Tai Chung ),유정현 ( Jeong Hyun Yoo ),박재형 ( Jai Hyung Park ),김주학 ( Joo Hak Kim ) 대한스포츠의학회 2007 대한스포츠의학회지 Vol.25 No.2

대전자 부위의 골절을 동반한 불안정 대퇴 전자간 골절 치료에 있어 전자부 안정화 금속판의 유용성을 높이는 방법 - 강선 및 나사를 이용한 대전자부 고정 -

김주학 ( Joo Hak Kim ),박재형 ( Jai Hyung Park ),김형수 ( Hyung Soo Kim ),정수태 ( Soo Tai Chung ),유정현 ( Jeong Hyun Yoo ),차승도 ( Seung Do Cha ),박상준 ( Sang Joon Park ),조주원 ( Joo Won Joh ) 대한고관절학회 2007 Hip and Pelvis Vol.19 No.1

목적: 노인의 불안정 대퇴 전자간 골절의 치료에 있어 압박 고나사와 전자부 안정화 금속판을 함께 사용 시 대체로 우수 한 결과를 보이나 대전자의 분쇄가 동반된 불안정 골절의 경우 과도한 감입을 보이는 경우가 있어 이에 대한 해결책으로 강선과 나사를 이용한 대전자의 추가 고정의 유용성을 평가하고자 한다. 재료 및 방법: 2004년 3월부터 2005년 12월 사이에 65세 이상의 대전자의 골절을 동반한 불안정 대퇴골 전자간 골절에 대해 활강 압박고 나사와 전자부 안정화 금속판을 함께 사용하여 수술을 시행하고 6개월 이상 추시 가능했던 환자 37예를 대상으로 하였으며, 평균 추시 기간은 13.5개월이었다. 활강 압박고 나사와 전자부 안정화 금속판만을 이용해 수술한 군(A군: 20예), 추가로 강선과 나사를 이용하여 골절된 대전자를 고정한 환자군(B군: 17예)으로 구분하였으며, A군의 평균 연령은 80.9세(범위: 68~89세), B군의 평균 연령은 83.2세(범위: 72~91세)였다. 수술 직후와 최종 추시 방사선학적 평가를 비교하여 지연나사의 활강 정도, 대전자의 전위 정도를 통계적으로 분석하였다. 결과: 최종 추시 시 A군의 2예를 제외하고 모두 골유합을 얻었으며 지연나사의 활강 정도는 A군에서 평균 8.96±5.98mm였고, B군에서 4.80±3.68 mm로 통계학적으로 의미 있는 차이를 보였다(P value<0.05). 대전자의 전위 정도는 A군에서 평균 2.06±2.86 mm였고, B군에서 평균 0.99±1.41 mm로 통계학적 의미는 없었다(P value>0.05). 결론: 불안정 대퇴 전자간 골절의 치료에 활강 압박고 나사와 전자부 안정화 금속판이 유용하나 대전자부 골절선이 있으면서 내측부 결손이 심한 경우 감입되면서 금속판 밖으로 대전자부 골절편이 전이되며 과도한 활강이 일어나는 경우가 있어 강선이나 나사 고정이 이를 막아 전자부 안정화 금속판이 대전자를 지지하도록 하여 금속판의 유용성을 증가시켜줄 것으로 사료된다. Purpose: The clinical outcome is favorable for the treatment of unstable femoral intertrochanteric fractures using both dynamic hip screw (DHS) and trochanter stabilizing plate (TSP) in elderly patients. However, there are sometimes complications related to excessive sliding. Therefore, the aim of this study was to evaluate the value of additional fixation of greater trochanter using wires and screw in the unstable femoral intertrochanteric fractures with a greater trochanter fracture. Materials and Methods: From March 2004 through December 2005, thirty-seven patients, who were more than sixty-five years of age and were diagnosed with osteoporosis, were treated with DHS and TSP in unstable femoral intertrochanteric fractures with a follow-up of more than 6 months (mean duration, 13.5 months). The patients were divided into two groups. One group (group A: 20 patients) was treated with DHS and TSP only, whereas the other (group B: 17 patients) was treated with DHS and TSP augmented by a wire and screw. The average age was 80.9 (range 68 to 89) and 83.2 years (range 72 to 91) in groups A and B, respectively. All the patients in both groups were assessed radiographically immediately after surgery and at the last follow-up. The level of sliding of the lag screw and displacement of the greater trochanter were evaluated statistically. Results: Bony union was achieved in all cases except for two cases in group A. At the last follow-up, the average of lag screw sliding in groups A and B was 8.96±5.98mm and 4.80±3.68, respectively, showing a statistical difference (P value<0.05). The average greater trochnateric displacement in groups A and B was 2.06±2.86mm and 0.99±1.41mm, respectively, showing no statistical significance (P value > 0.05). Conclusion: Unstable femoral intertrochanteric fractures can be treated successfully using a hip screw and TSP alone. However, the addition of wires and screws in the greater trochanter can prevent excessive sliding that occurs after displacing the greater trochanteric fragments out of the plate in the presence of a greater trochanteric fracture line or severe bone defect in the lateral aspect.

원위 요골 골절에서 고정각과 가변각 수장측 잠김 금속판을 이용한 수술의 비교

차승도 ( Seung Do Cha ),박재형 ( Jai Hyung Park ),김형수 ( Hyung Soo Kim ),정수태 ( Soo Tae Chung ),유정현 ( Jeong Hyun Yoo ),김주학 ( Joo Hak Kim ),박정환 ( Jung Hwan Park ) 대한골절학회 2012 대한골절학회지 Vol.25 No.3

목 적: 원위 요골 골절 환자에서 고정각 수장측 잠김 금속판을 이용한 군과 가변각 수장측 잠김 금속판을 이용한 군의 결과를 비교하고자 하였다. 대상 및 방법: 술 후 최소한 6개월 이상의 추시 관찰이 가능하였던 41예를 대상으로 하였으며, 치료 결과의 판정을 위해 관절 운동범위, visual analogue scale score 및 Disabilities of the Arm, Shoulder and Hand Questionnaire score를 이용한 임상적 평가 및 방사선학적 평가를 시행하였다. 결과: 임상적 결과 및 방사선학적인 결과 모두에서 고정각 잠김 금속판을 이용한 군과 가변각 잠김 금속판을 이용한 군에서 통계학적으로 차이를 보이지 않았다. 결론: 원위 요골 골절에서 잠김 금속판의 종류에 따른 수술적 결과의 유의한 차이는 없었으나, 골편의 모양에 따른 적절한 금속판 선택을 하여 수술을 시행해 나사못과 금속판에 의한 합병증을 최소화하도록 노력하는 것이 중요하다고 생각한다. Purpose: To compare the outcomes of distal radius fractures in a fixed-angle volar locking plate group and variable-angle volar locking plate group. Materials and Methods: Forty-one patients observed at least 6 months after surgery were included in this retrospective study. We used the range of motion, visual analogue scale score, Disabilities of the Arm, Shoulder and Hand Questionnaire score, and radiologic findings to measure the clinical results. Results: No differences in clinical results or radiologic results were noted between the fixed-angle volar locking plate group and variable-angle volar locking plate group. Conclusion: We believe that it is important to minimize complications by using appropriate screws and plates according to the fracture type, though no differences in the surgical outcome were noted between the fixed-angle volar locking plate group and variable-angle volar locking plate group with distal radius fracture.

증례 보고 : 월상골과 삼각골의 동반골절 -1예 보고-

김주학 ( Joo Hak Kim ),김형수 ( Hyung Soo Kim ),정수태 ( Soo Tae Chung ),유정현 ( Jeong Hyun Yoo ),차승도 ( Seung Do Cha ),이중효 ( Joong Hyo Lee ),박재형 ( Jai Hyung Park ) 대한골절학회 2008 대한골절학회지 Vol.21 No.4

Evaluation of Citric Acid Added Cleaning Solution for Removal of Metallic Contaminants on Si Wafer Surface

KIM, KYUNG SOO,Yoo, Hak Do,Chung, Hye Young,Cho, Hyo Yong,Lee, Bo Young,Lee, Sang Hak 한국화학공학회 2001 Korean Journal of Chemical Engineering Vol.18 No.3

We have investigated cleaning solutions based on citric acid (CA) to remove metallic contaminants from the silicon wafer surface. Silicon wafers were intentionally contaminated with Fe, Ca, Zn, Na, Al and Cu standard solution by spin coating method and cleaned in various CA-added cleaning solutions. The concentration of metallic contanunants on the silicon wafer surface before and after cleaning was analyzed by vapor phase decomposition/inductively coupled plasma-mass spectrometry (VPD/ICP-MS). And the surface micro-roughness was also measured by atomic force microscopy (AFM) to evaluate the effect of cleaning solutions. It was found that acidic CA/H₂0 solution has the ability to remove metallic contaminants from silicon surfaces. Fe, Ca, Zn and Na on silicon surface were decreased from the order of 10^(12) atoms/cm²to the order of 10^9 atoms/cm²even at low CA concentration, low temperature of CA solution and with short immersion time. CA was also effective in alkali cleaning solution. Fe, Ca, Zn, Na and Cu were reduced down to the order of 10^9 atoms/cm²in CA added with NH₄OH/H₂O₂/H₂O solution without degradation of surface micro-roughness.

Role of Ras/ERK-dependent pathway in the erythroid differentiation of K562 cells

Kang, Chi-Dug,Do, In-Rok,Kim, Kwang-Woon,Ahn, Byung-Kwon,Kim, Sun-Hee,Chung, Byung-Seon,Jhun, Byung-Hak,Yoo, Mi-Ae 부산대학교 유전공학연구소 1999 분자생물학 연구보 Vol.15 No.-

The chronic myelogenous leukemic K562 cell line carrying Bcr-Abl tyrosine kinase is considered as pluripotent hematopoietic progenitor cells expressing markers for erythroid, granulocytic, monocytic, and megakaryocytid lineages. Here we investigated the signaling modulations required for induction of erythroid differentiation of K562 cells. When the K562 cells were treated with herbimycin A(an inhibitor of protein tyrosine kinase), ras antisense oligonucleotide, and PD98059 (a specific inhibitor of MEK), inhibition of ERK/MAPK activity and cell growth, and induction of erythroid differentiation were observed. The ras mutant, pZIPRas^61leu -transfected cells, K562-Ras^61leu have shown a markedly decreased cell proliferation rate with approximately 2-fold doubling time, compared with 2-fold doubling time, compared with the parental K562 cells, and about 60% of these cells have shown the phenotype of erythroid differentiation. In addition, herbimycin A inhibited the growth rate and increased the erythroid differentiation, but did not affect the elevated activity of ERK/MAPK in the K562-Ras^61leu cells. On the other hand, effects of PD98059 on the growth and differentiation of K562-Ras^61leu cells were biphasic. At low concentration of PD98059, which inhibited the elevated activity of ERK/MAPK to the level of parental cells, the growth rate increased and the erythroid differentiation decreased slightly, and at high concentration of PD98059, which inhibited the elevated activity of ERK/MAPK below that of the parental cells, the growth rate turned down and the erythroid differentiation was restored to the untreated control level. Taken together, these results suggest that an appropriate activity of ERK/MAPK is required to maintain the rapid growth and transformed phenotype of K562 cells.

Numerical Analysis for the Dynamics of the Oxidation - Induced Stacking Fault in Czochralski - Grown Silicon Crystals

Wang, Jong Hoe,Oh, Hyun Jung,Yoo, Hak Do 한국화학공학회 2001 Korean Journal of Chemical Engineering Vol.18 No.1

The continuum model of point defect dynamics to predict the concentration of interstitial and vacancy is established by estimating expressions for the thermophysical properties of point defects and the point defect distribution in a silicon crystal and the position of oxidation-induced stacking fault ring (R-OiSF) created during the cooling of crystals in Czochralski silicon growth process are calculated by using the finite element analysis. Temperature distributions in the silicon crystal in an industrial Czochralski growth configuration are measured and compared with finite volume simulation results. These temperature fields obtained from finite volume analysis are used as input data for the calculation of point defect distribution and R-OiSF position. Calculations of continuum point defect distributions predict the transition between vacancy and interstitial dominated precipitations of microdefects as a function of crystal pull rate (V). The dependence of the radius of R-OiSF (R_(OiSF)) on the crystal length with fixed growth rate for a given hot zone configuration is examined. The R_(OiSF) is increased with the increase of crystal length. These predictions from point defect dynamics are well agreed with experiments and empirical V/G correlation qualitatively, where G is the axial temperature gradient at the melt/crystal interface.