2개의 내측 유관나사를 이용한 관절경하에서의 족근 관절 고정술

김학준,김택선,윤정로,김경수,노행기,윤광섭,Kim, Hak-Jun,Kim, Taik-Seon,Yoon, Jeong-Ro,Kim, Kyoung-Soo,Noh, Haeng-Kee,Yoon, Kwang-Sup 대한족부족관절학회 2004 대한족부족관절학회지 Vol.8 No.2

Purpose: We evaluated the clinical and radiological results of arthroscopic ankle fusion using 2 medial screws which had advantages of less morbidity, early weight-bearing and high union rate. Material and Methods: From April, 2002 to March, 2004, 8 patients who had ankle osteoarthritis were treated by ankle fusion using 2 medial screws under arthroscopy; five patients with post-traumatic osteoarthritis, two with post-infectious arthritis and one with paralytic foot. There were 5 male and 3 female. Average age was 67 years old ranging from 57 to 71 years. We evaluated them clinically preoperative and postoperative using AOFAS score, VAS pain scale and patient's satisfaction. In regard to radiological fusion, we checked them by simple AP, lateral and mortise view. Follow up period was average 11 months (range, $6{\sim}24$ months). Results: All ankles were successfully fused with 2 medial screws under arthroscopy. The mean time of fusion was 10.5 weeks (range, $8{\sim}14$ weeks). Patient's satisfaction checked at 6 months after operation had favorable results (excellent and good 75%). One case had pain on medial malleolar area because of screw's protrusion. Conclusion: Arthroscopic ankle fusion using 2 medial screws was good modality of ankle fusion with less morbidity and early weight-bearing in some cases of ankle arthritis.

자동차 에어컨 컴퓨터 시뮬레이션

김학준,정동수,김종보,김기효,강정길,Kim, H.J.,Jung, D.S.,Kim, C.B.,Kim, K.H.,Kang, J.K. 대한설비공학회 1996 설비공학 논문집 Vol.8 No.2

The refrigeration cycle of automobile air-conditioners is simulated in an effort to provide a computational tool for optimum thermodynamic design. In the simulation, thermodynamic and heat transfer analysis was performed for the four major components : evaporator, condenser, compressor, and expansion valve. Effectiveness-NTU method was used for modeling both evaporator and condenser. The evaporator was divied into many subgrids and simultaneous cooling and dehumidifying analysis was performed for each grid to predict the performance accurately. Blance equations were used to model the compressor instead of using the compressor map. The performance of each component was checked against the measured data with CFC-12. Then, all the components were combined to yield the total system performance. Predicted cycle points were compared against the measured data with HFC-134a and the deviation was found to be less than 5% for all data. Finally, the system model was used to predict the performance of CFC-12 and HFC-134a for comparison. The results were very reasonable as compared to the trend deduced from the measured data.

대학순례-21세기 동북아의 중심대학, 인천대학교

김학준,Kim, Hak-Jun 한국대학교육협의회 1998 大學敎育 Vol.95 No.-

쇄골 상부 림프절을 포함하는 왼쪽 유방암의 VMAT 치료계획시 X-Jaw split을 이용한 선량비교에 관한 연구

김학준,이양훈,민제순,Kim, Hak Jun,Lee, Yang Hoon,Min, Jae Soon 대한방사선치료학회 2021 대한방사선치료학회지 Vol.33 No.-

목 적 : VMAT을 이용한 쇄골 상부 림프절을 포함하는 왼쪽 유방암 치료 시 X-Jaw를 나눈 치료계획과 기존 Full field VMAT 치료계획과의 선량분포를 비교 분석하여 X-Jaw split VMAT의 유용성을 평가하였다. 대상 및 방법 : 쇄골 상부 림프절을 포함하는 왼쪽 유방암 환자 10명을 대상으로 Vacuum cushion을 이용하여 CT simulation 하고 2 Arc Full field VMAT과 4 Arc X-Jaw split VMAT을 각각 치료계획 하였다. 각 치료계획은 처방 선량(Prescription dose)이 치료계획표적용적(Planning Target Volume, PTV)의 95% 이상 포함이 되고 주변 정상장기(Organ at risk, OAR)에 최소한으로 조사되도록 설계하였다. 이후 선량체적용적(Dose volume histogram, DVH)을 통해 PTV과 OAR의 대한 선량분석을 하였다. 결 과 : 10명의 환자의 Full field VMAT치료계획과 X-Jaw split VMAT치료계획의 데이터를 평균값으로 나타내어 비교하였다. 처방선량지수(conformity index, CI) 1.05±0.04, 1.04±0.03, 선량균질지수(homogeneity index, HI) 1.07±0.008, 1.07±0.009 로 두 치료계획 간 차이는 크지 않았다. OAR의 경우 왼쪽 폐의 V5 56.1±6.50%, 50.4±6.30%, V20 20.0±4.15%, 13.52±3.61% 로 Full field VMAT대비 X-Jaw split VMAT에서 V5이 10.0% V20은 32.6% 감소하였다. 심장의 V30은 3.68±1.85%, 2.23±1.52%, 평균 선량은 8.93±1.65 Gy, 7.67±1.52 Gy로 X-Jaw split VMAT에서 V30은 39.3%, 선량은 14.1% 감소하였다. 정상조직인 왼쪽 폐와 심장은 통계적 유의 수치인 p-value 0.05미만으로 나타났다. 결 론 : PTV의 체적이 크고 X Jaw의 길이가 15 cm 이상이 되는 쇄골 상부 림프절을 포함하는 왼쪽 유방암치료의 경우 X-Jaw split VMAT 치료계획은 기존의 치료계획과 동등한 HI와 CI로 유사한 PTV coverage를 유지 하면서 개선된 선량분포를 나타내 OAR인 폐와 심장 등의 방사선량을 줄일 수 있어 부작용을 줄이는데 효과적이라고 생각된다. Purpose : The usability of X-Jaw split VMAT was evaluated by comparative analysis of the dose distribution between the treatment plan divided by X-Jaw and Full field VMAT treatment plan in left breast cancer treatment including supraclavicular lymph nodes. Materials and Methods : 10 patients with left breast cancer, including supraclavicular lymph nodes, were simulated using vacuum cushion, and 2 Full field Arc VMAT and 4 X-Jaw split Arc VMAT were planned The treatment plan was designed to include more than 95% of the Planning Target Volume (PTV) and to be minimally irradiated in the surrounding Organ at risk (OAR). Dose analysis of PTV and OAR was performed through dose volume histogram (DVH). Results : The Full field VMAT treatment plan and the X-Jaw split VMAT treatment plan of 10 patients were expressed as average values and compared. The difference between the two treatment plans was not large, with a Conformity index (CI) of 1.05±0.04, 1.04±0.03, and a Homogeneity index (HI) of 1.07±0.008, 1.07±0.009. For OAR, V5 in the left lung is 56.1±6.50%, 50.4±6.30%, and V20 is 20.0±4.15%, 13.52±3.61%. Compared to Full field VMAT, V5 decreased by 10.0% V20 by 32.6% in X-Jaw split VMAT. The V30 of the heart is 3.68±1.85%, 2.23±1.52%, and the Mean dose is 8.93±1.65 Gy, 7.67±1.52 Gy. In the X-Jaw split VMAT, V30 decreased by 39.3% and the Mean dose decreased by 14.1%. The left lung and heart, which are normal tissues, were found to have a statistical significance of that p-value is less than 0.05. Conclusion : In the case of left breast cancer treatment, which includes Supraclavicular lymph nodes with a large PTV volume and a length of X Jaw of 15 cm or more, the X-Jaw split VMAT shows improved dose distribution, which can reduce radiation dose of OAR such as lungs and heart, while maintaining similar PTV coverage with HI and CI equivalent to Full field VMAT. It is thought to be effective in reducing radiation complications.

모톤씨 신경종 크기에 따른 초음파 유도하 스테로이드 주사 효과의 비교분석

김학준,허창룡,김재균,장규선,Kim, Hak Jun,Hur, Chang Ryong,Kim, Jae Kyun,Jang, Kyu Seon 대한정형외과초음파학회 2012 대한정형외과 초음파학회지 Vol.5 No.2

목적: 족부에 발생하는 여러 질환 중 모톤씨 신경종은 종족골두 사이에서 지속적인 마찰로 인한 자극으로 발생되며 보행 시 통증과 감각이상을 호소한다. 일차적인 치료는 중족골 패드, 스테로이드 주사, 비스테로이드성 진통제를 사용하는 비수술적인 치료 방법이 권장되고 있다. 초음파의 발달로 인해 모톤씨 신경종을 진단하고 그 크기를 쉽게 확인 할 수 있으며 스테로이드도 정확한 부위에 주사할 수 있게 되었다. 이에 저자들은 초음파 영상 하의 스테로이드 주사에 대한 임상적 결과를 분석하고자 하였다 대상 및 방법: 2008년 10월부터 2011년 9월까지 임상적 및 초음파 검사 하에서 모톤씨 신경종으로 진단받은 17명(23례)을 대상으로 연구를 시행하였다. 모든 환자가 여성이었고, 평균 나이는 52.6세(36~72)이었다. 병변의 종축과 횡축의 크기를 측정하였고, 5 mg의 dexamethasone을 초음파 영상 유도 하에 신경종 주위에 주사하였다. 주사 전, 후의 자가 통증 점수(VAS pain score)를 기록하였고, 주사 후 환자의 만족도를 완쾌, 호전, 비호전, 악화로 분류 하였으며 SPSS 프로그램을 이용한 t-test를 이용하여 병변의 크기에 따른 steroid 주사의 효과를 비교 분석하였다. 결과: 1예에서 제1 중족지간에, 11예에서 제2 중족지간에 신경종이 발생하였고, 11예는 제3 중족지간에 발생하였다. 신경종의 평균 종축의 길이는 $0.8{\pm}0.4cm$, 횡축의 길이는 $0.52{\pm}0.17cm$이었다. 총 23례 중 증상의 완쾌 및 호전은 7례(30.4%)이었고 비호전 및 악화의 예는 16례(69.6%)이었다. 만족도가 완쾌 및 호전이었던 군의 신경종 종축의 평균길이는 $0.71{\pm}0.39cm$이었고 횡축의 평균 길이는 $0.47{\pm}0.24cm$이었으며, 만족도가 비호전 및 악화 이었던 군의 신경종 종축의 크기는 $0.83{\pm}0.42cm$, 횡축의 길이는 $0.54{\pm}0.14cm$이었다. 종축의 길이가 5 mm 미만, 횡축의 크기가 4 mm 미만인 신경종 군에서 주사 후 자가 통증 점수와 만족도가 종축이 5 mm, 횡축이 4 mm이상인 신경종보다 통계학적으로 의미 있게 임상 결과가 좋은 것으로 분석되었다(p<0.05). 결론: 모톤씨 신경종에서 초음파 영상은 진단 및 치료에 중요한 영상기법으로 생각되며 신경종의 횡축 길이가 0.5 cm, 종축 길이가 0.4 cm 미만인 경우에는 스테로이드 주사가 효과적인 것으로 사료된다. Purpose: The aim of this study was to evaluate the effectiveness of ultrasound-guide steroid injection according to Morton's neuroma size. Materials and Methods: From October 2008 to September 2011, 17 patients (23 cases) diagnosed with Morton's neuroma were investigated. All cases were female and mean age was 52.6 years old. Neuroma were measured by the horizontal and longitudinal length of the mass and underwent ultrasound-guided steroid (5 mg dexamethasone) injection. The efficacy of the injection was determined by Visual Analogue Scale pain score and patient satisfaction(subdivided 4 group-much improved, improved, not improved, aggrevation) Results: 7 of 23(30.4%) cases showed much improved and improved satisfaction and mean longitudinal and horizontal length were $0.71{\pm}0.39cm$ and $0.47{\pm}0.24cm$, respectively. 16 of 23(69.6%) cases showed not improved and aggrevation satisfaction and mean longitudinal and horizontal length were $0.83{\pm}0.42cm$ and $0.54{\pm}0.14cm$, repectively. There was a significant difference in VAS and patient satisfaction in case longitudinal and horizontal length were smaller than 0.5 cm and 0.4 cm. (p<0.05) Conclusion: The ultrasonography is a important modality in diagnosis and treatment of morton's neuroma. Ultrasound-guide steroid injection is effective in case longitudinal and horizontal length were smaller than 0.5 cm and 0.4 cm, respectively.

터널 숏크리트 계측의 개선방안

김학준,박시현,배규진,Kim, Hak-Joon,Park, Si-Hyun,Bae, Gyu-Jin 한국터널지하공간학회 2010 한국터널지하공간학회논문집 Vol.12 No.2

터널현장에서는 터널의 안정성을 평가하기 위하여 숏크리트 계측이 활발히 수행되고 있다. 그러나 숏크리트 응력 측정은 지반하중과 관계없이 발생되는 변형률 및 숏크리트 변형계수의 불확실성, 숏크리트 응력 측정 자체의 어려움 등에 의하여 측정 결과의 신뢰성을 기대하기 어렵다. 본 연구에서는 국내외의 숏크리트 계측의 현황 분석 및 현장 계측 결과를 통하여 기존 숏크리트 계측의 문제점을 분석하였다. 문헌조사 및 터널 현장에서의 무응력 숏크리트 계측 결과를 이용하여 무응력 상태에서 발생하는 숏크라트 응력의 보정 방안을 제시하였다. 또한 측정된 변형률을 응력으로 환산할 경우에 적용할 숏크리트 변형계수를 제시하였다. The field measurements on the shotcrete lining are usually performed during the tunnel construction. However, the credibility of the measurements is not certain because of the non-stress related strains occurring in the shotcrete, the uncertainty of the deformation modulus of the shotcrete, and the intrinsic difficulties involved in the strain measurements in the shotcrete. The problem related to the field measurements on the shotcrete is investigated using the review of the previous studies and the field measurement performed for this study. A method for the correction of stress measurements at the shotcrete lining, considering the non-stress related strains, is suggested using the literature review and the actual measurements obtained from the non-stress shotcretes. The deformation modulus used for the calculation of the stress acting on the shotcrete is also suggested.

고효율 수퍼히트펌프에 관한 전산 해석

김학준,정동수,김종보,하경용,Kim, H.J.,Jung, D.S.,Kim, C.B.,Ha, K.Y. 대한설비공학회 1995 설비공학 논문집 Vol.7 No.2

A super-heat pump system composed of a suction line heat exchanger, low and high stage economizers, and a screw compressor is simulated to examine the energy performance and design options. CFC12, HCFC22, HFC134a, HCFC22/HCFC142b, HFC32/HFC134a, and HFC125/HFC134a are used as working fluids for comparison. The results indicate that the proposed system charged with appropriate mixtures is up to 33.4% more energy efficient than the normal system with CFC12. The performance of the super-heat pump system charged with mixtures was influenced by such factors as the temperature matching, heat source temperature difference, low stage economizer, and high stage economizer. The fluids with a larger liquid specific heat such as HFC134a would have more benefits when a suction line heat exchanger is installed. 40%HCFC22/60%HCFC142b mixture seems to be a good candidate to replace CFC12. On the other hand, 25%HFC32/75% HFC134a would be a good long term candidate to replace HCFC22.

재발한 족관절의 미만성 색소 융모 결절성 활액막염

김학준,김택선,서동훈,윤광섭,정국진,전승주,Kim, Hak-Jun,Kim, Taik-Seon,Suh, Dong-Hun,Yoon, Kwang-Sup,Chung, Kuuk-Jin,Jeon, Seung-Ju 대한족부족관절학회 2005 대한족부족관절학회지 Vol.9 No.2

Pigmented villonodular synovitis (PVNS) in ankle is relatively uncommon. This disorder results in increased proliferation of synovium causing villous or nodular changes containing histiocytes, fibroblasts, multinucleated giant cell, and hemosiderin. PVNS is classified into two different type : localized and diffuse. Diffuse type of PVNS in ankle is more common than localized type. Also, recurrence of diffuse type is more frequent. We report a case of diffuse type of PVNS which was recurred soon after the excision.

2003년부터 2015년까지 CA 인증 공기청정기의 성능 시험 결과 분석

김학준,홍기정,우창규,한방우,김용진,Kim, Hak-Joon,Hong, Kee-Jung,Woo, Chang Gyu,Han, Bangwoo,Kim, Yong-Jin 한국입자에어로졸학회 2017 Particle and Aerosol Research Vol.13 No.1

In this study, the test results obtained from the performance tests for CA (Korea Association of Cleaning Air) certificated air cleaners which had been commercially available in Korea from 2003 to 2015 were analyzed. Among the test parameters such as flow rate, particle collection efficiency, clean air delivery rate (CADR), ozone emission, odor removal efficiency and noise level, noise level and CADR were correlated with flow rates. Collection and odor removal efficiencies were 20% higher than the limit of the CA certification. The ozone emissions from the air cleaners were negligible because all the air cleaners were equipped with only HEPA filters, not electrostatic precipitation method which produces ozone.

경제성 분석에 의한 싱글쉘 터널의 국내 적용성 검토 연구

김학준,신휴성,Kim, Hak-Joon,Shin, Hyu-Seong 한국터널지하공간학회 2008 한국터널지하공간학회논문집 Vol.10 No.2

터널공사비에 대한 국내외의 사례 조사 결과 싱글쉘 터널은 기존의 콘크리트 라이닝을 설치하는 이중쉘 터널에 비하여 공사비가 저렴하였다. 그러나 암반 상태가 불량해 질수록 싱글쉘 터널의 경제성은 급격히 저하되었다. 따라서 싱글쉘 공법은 암반상태가 양호한 지반에 적용해야 한다. 국내의 경우 일반적으로 여러 암반 등급이 다양하게 나타나므로 양호한 암반과 불량한 암반의 비율을 고려하여 싱글쉘 공법의 적용 여부를 판단해야 한다. 싱글쉘에 이용되는 숏크리트 및 록볼트는 영구지보재로서 고품질이어야 하므로 지보재료의 저렴한 공급여부에 따라서 싱글쉘 공법의 적용 대상 암반이 확대될 수 있을 것으로 기대된다. The construction cost for the single shell tunnel is cheaper than that of the double shell tunnel according to the case studies performed in several domestic and foreign tunnels. However, the economic advantage of single shell tunnel drops drastically as the condition of the rock mass deteriorates. Therefore, the single shell tunnelling method should be applied to the good rock mass conditions. The application of the single shell tunnelling method to tunnels in Korea should be determined considering the ratio between the good rock and poor rock masses along the tunnel section. The use of the single shell tunnel is expected to offend depending on the cheap supply of high quality shotcrets and rock bolts developed for single shell tunnels.