Development of a high-speed impedance measurement system for dual-frequency capacitive-coupled pulsed-plasma.

Lee, Hohyoung,Lee, Jeongbeom,Park, Gijung,Han, Yunseok,Lee, Youngwook,Cho, Gunhee,Kim, Hanam,Chang, Hongyoung,Min, Kyoungwook American Institute of Physics 2015 Review of scientific instruments Vol.86 No.8

<P>A high-speed impedance measurement system was developed, which enables the measurement of various characteristics of CW and pulsed plasmas with time resolution of less than a microsecond. For this system, a voltage and current sensor is implemented in a printed circuit board to sense the radio frequency signals. A digital board, which has a high-speed analog to digital converter and a field-programmable gate-array, is used to calculate the impedance of the signal. The final output of impedance is measured and stored with a maximum speed of 3 Msps. This sensor system was tested in a pulsed-plasma by applying it to the point between the matching box and the plasma chamber. The experimental equipment was constructed connecting the matching box, a 13.56 MHz generator, a 2 MHz generator that produced pulsed power, and a pulse-signal generator. From the temporal behavior of the measured impedance, we were able to determine the time intervals of transient states, especially of the initial active state. This information can be used to set the pulse frequency and duty for plasma processing.</P>

Han'guk kidokkyo suyongsa yǒn'gu (A Study on the History of the Korean Reception of Christianity). By Manyǒl Yi . Seoul: Tureshidae, 1998. 544 pp., 15,000 wǒn

Hohyoung Lee(서평자) The Academy of Korean Studies 1999 THE REVIEW OF KOREAN STUDIES Vol.2 No.-

Large Focal Extrapleural Hematoma of Chest Wall: A Case Report

( Hohyoung Lee ),( Sung Ho Han ),( Min Koo Lee ),( Oh Sang Kwon ),( Kyoung Hwan Kim ),( Jung Suk Kim ),( Soon-ho Chon ),( Sung Ho Shinn ) 대한외상학회 2019 大韓外傷學會誌 Vol.32 No.2

Although hemothorax and pneumothorax are common complications seen in rib fractures, focal extrapleural hematoma is quite rare. We report a 63-year-old female patient that developed large focal extrapleural hematoma after falling off a second floor veranda. The patient had sustained 3, 4, 5th costal cartilage rib fractures and a sternum fracture. She had developed suspected empyema with loculations with small amount of hemothorax. She underwent a planned early decortication/adhesiolysis by video assisted thoracoscopic surgery at the 12th post-trauma day due to failed drainage. Unexpectedly, she had no adhesions or any significant retained hematoma mimicking a mass, but was found with the focal extrapleural chest wall hematoma. She was discharged on postoperative 46th day for other reasons and is doing fine today.

Bilateral Chylothorax Due to Blunt Spine Hyperextension Injury: A Case Report

( Hohyoung Lee ),( Sung Ho Han ),( Min Koo Lee ),( Oh Sang Kwon ),( Kyoung Hwan Kim ),( Jung Suk Kim ),( Soon-ho Chon ),( Sung Ho Shinn ) 대한외상학회 2019 大韓外傷學會誌 Vol.32 No.2

Bilateral chylothorax due to blunt trauma is extremely rare. We report a 74-year-old patient that developed delayed bilateral chylothorax after falling off a ladder. The patient had a simple 12th rib fracture and T12 lamina fracture. All other findings seemed normal. He was sent home and on the 5th day visited our emergency center at Halla Hospital with symptoms of dyspnea and lower back pain. Computer tomography of his chest presented massive fluid collection in his right pleural cavity and moderate amounts in his left pleural cavity with 12th rib fracture and T11-12 intervertebral space widening with bilateral facet fractures. Chest tubes were placed bilaterally and chylothorax through both chest tubes was discovered. Conservative treatment for 2 weeks failed, and thus, thoracic duct ligation was done by video assisted thoracoscopic surgery. Thoracic duct embolization was not an option. Postoperatively, the patient is now doing well and happy with the results. Early surgical treatment must be considered in the old patient, whom large amounts of chylothorax are present.

Percutaneous screw fixation and external stabilization as definitive surgical intervention for a pelvic ring injury combined with an acetabular fracture in the acute phase of polytrauma in Korea: a case report

Lee Hohyoung,Cho Myung-Rae,Song Suk-Kyoon,Yoon Euisun,Lee Sungho 대한외상학회 2023 大韓外傷學會誌 Vol.36 No.3

Unstable pelvic ring injuries are potentially life-threatening and associated with high mortality and complication rates in polytrauma patients. The most common cause of death in patients with pelvic ring injuries is massive bleeding. With resuscitation, external fixation can be performed as a temporary stabilization procedure for hemostasis in unstable pelvic fractures. Internal fixation following temporary external fixation of the pelvic ring yields superior and more reliable stabilization. However, a time-consuming extended approach to open reduction and internal fixation of the pelvic ring is frequently precluded by an unacceptable physiologic condition and/or concomitant injuries in patients with multiple injuries. Conservative treatment may lead to pelvic ring deformity, which is associated with various functional disabilities such as limb length discrepancy, gait disturbance, and sitting intolerance. Therefore, if the patient is not expected to be suitable for additional surgery due to a poor expected physiologic condition, definitive external fixation in combination with various percutaneous screw fixations to restore the pelvic ring should be considered in the acute phase. Herein, we report a case of unstable pelvic ring injury successfully treated with definitive external fixation and percutaneous screw fixation in the acute phase in a severely injured polytrauma patient.

대퇴골 원위부 골절의 역행성 골수강내 금속정 고정술 시후방 각 변형을 일으키는 요인

이호형 ( Hohyoung Lee ),정지호 ( Ji-ho Jeong ),김민수 ( Min-su Kim ),김범수 ( Bum-soo Kim ) 대한골절학회 2018 대한골절학회지 Vol.31 No.2

목적: 역행성 골수강내 금속정을 이용한 원위 대퇴 골절 치료시 시상면상 후방 각 형성에 영향을 미치는 요인을 분석하고자 하였다. 대상 및 방법: 역행성 골수강내 금속정 고정술 후 최소 12개월 이상 추시가 가능하였던 55예를 대상으로 후향적으로 분석하였다. 술 후 방사선 영상으로 골절 위치 및 유형에 따른 후방 각 변형의 정도를 비교 분석하였으며, 정상 성인 100명의 대퇴골 측면 사진을 이용한 이상적 삽입점을 찾고 이를 실제 골수강내 금속정의 삽입점과 비교하여 삽입 위치에 따른 후방 각 변형의 정도를 분석하였다. 결과: 골절 위치에 따른 후방 각 형성의 차이는 없었으며 골절 유형에 따른 후방 각 형성에 유의한 차이가 있었다 (p=0.047). 골절 정복이 불완전한 상태를 용납하고 수술하여 삽입점이 후방으로 위치할수록 후방 각 형성이 유의하게 증가하였다(p=0.012). 결론: 대퇴골 원위부의 횡골절은 다른 유형에 비해 후방 각 형성이 적었으며, 골수강내 금속정 삽입점을 Blumensaat’s line 정점으로부터 후방에 위치시킬수록 후방 각 형성이 증가함을 알 수 있었다. Purpose: To analyze the factors that cause a posterior angulatory deformity in the retrograde intramedullary nailing of distal femoral fractures. Materials and Methods: Fifty-five patients with distal femur fractures who were treated with retrograde intramedullary nailing were enrolled in this study. They were followed-up for at least one year postoperatively. The posterior angulatory deformity was evaluated according to the fracture location, pattern, and insertion point and the insertion point was compared with the ideal point derived from the radiographs of 100 normal adults. The correlation between the posterior angulation and the entry point of the nail was analyzed. Results: The posterior angulation was similar in terms of the fracture location; a meaningful difference was noted among the fracture patterns (p=0.047). The posterior angulation was significantly greater when the entry point was located more posteriorly, accepting a malreduced state (p=0.012). Conclusion: Posterior angulation was smaller in the transverse fracture and the posterior location of the entry point from the apex of the Blumensaat’s line increased the posterior angulation.

Spinopelvic Orientation on Radiographs in Various Body Postures: Upright Standing, Chair Sitting, Japanese Style Kneel Sitting, and Korean Style Cross-Legged Sitting

문명상,Hohyoung Lee,Seong-Tae Kim,김상재,김동석 대한정형외과학회 2018 Clinics in Orthopedic Surgery Vol.10 No.3

Background: Several previous studies reported on the impact of upright standing and chair sitting on the sagittal spinopelvic alignment. However, there are no studies on the impact of the two Asian (Korean and Japanese) style floor-sitting positions on the sagittal spinopelvic alignment. The purpose of this study was to evaluate the impact of four different body postures (standing, chair sitting, kneel sitting, and cross-legged sitting) on the sagittal spinopelvic alignment. Methods: Sixteen selected healthy volunteers (10 males and six females) were subjects of this pilot study. In all subjects, radiographs were taken in comfortable standing and sitting positions. All spinal curvatures including lumbar lordotic angle (LLA), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI) were measured on the radiographs. Results: In standing position, the average LLA, SS, PT, and PI were 37.1°, 35.3°, 15.7°, and 51.0°, respectively. In chair sitting, the average LLA, SS, PT, and PI were 17.9°, 20.3°, 28.2°, and 49.5°, respectively. In kneel sitting (Japanese style), the average LLA, SS, PT, and PI were 31.8°, 38.3°, 14.2°, and 52.5°, respectively. In cross-legged sitting (Korean style), the average LLA, SS, PT, and PI were 9.8°, 13.4°, 38.3°, and 51.7°, respectively. LLA in standing (37.1°) and kneel sitting (31.8°) were very similar. Remarkable reduction in LLA was observed in Korean-style cross-legged sitting (9.8°), and LLA in chair sitting (17.9°) was about half of that in standing. SS was similar in standing (35.3°) and kneel sitting (38.3°), and it was reduced remarkably in cross-legged sitting (13.4°). PT was largest in cross-legged sitting (38.3°), and it was similar between standing (15.7°) and kneel sitting (14.2°). PIs were similar in all positions. Conclusions: The kneel sitting position did not show significant differences with the standing position when assessed using four parameters related to the sagittal spinopelvic alignment, whereas chair sitting and cross-legged sitting positions significantly altered the spinopelvic alignment compared to the standing position.

영상처리 소프트웨어 개발을 위한 비주얼 프로그래밍 환경

정호형(Jung Hohyoung),이철우(Chil-Woo Lee),오원근(Weon-Geun Oh) 한국정보과학회 1998 한국정보과학회 학술발표논문집 Vol.25 No.2Ⅱ

본 논문에서는 데이터 플로우 표현방식을 이용한 비주얼 프로그램으로 개발하려는 소프트웨어의 프로토타입을 빠르고 쉽게 만들어 완성된 소프트웨어를 시뮬레이션 할 수 있는 환경을 제공하는 TOI(Task Operation Integrator) 시스템을 소개한다. 이 시스템은 Liveness를 제공하는 사용자가 효과적으로 프로그램을 작성할 수 있게 해주고 다양한 환경에 융통성 있게 확장 가능하다.

The Meniscofemoral Ligament Mimicking a Lateral Meniscus Tear

( Bong Keun Park ),( Hohyoung Lee ),( Seong-tae Kim ),( Min Geun Yoon ) 대한슬관절학회 2017 대한슬관절학회지 Vol.29 No.4

A 58-year-old male patient who had developed left knee pain with a history of trauma was referred to our hospital. Physical examination and further examination by magnetic resonance imaging revealed results that closely resemble a horizontal tear of the lateral meniscus and a tear of the medial meniscus. Arthroscopically, we found a cord-like structure originating from the posterior 1/3 portion of the lateral meniscus and passing obliquely toward the medial femoral condyle in front of the posterior cruciate ligament without a tear of the lateral meniscus. In this report, we describe a rare case of anterior meniscofemoral ligament that was clearly seen on arthroscopy and mimicked a meniscal tear, which is also known as a pseudo-tear of the meniscus.

골반환 손상과 동반된 고환 탈구

김범수(Bum-Soo Kim),이호형(Hohyoung Lee),김성태(Seong-Tae Kim),임현규(Hyeon Gyu Lim) 대한정형외과학회 2020 대한정형외과학회지 Vol.55 No.6

불안정성 골반환 손상은 고에너지 외상으로 발생하게 되는데 종종 비뇨기과적인 손상을 동반하기도 한다. 비뇨기과적 손상으로는 방광, 요관, 요도 손상이 흔하다. 고환 탈구는 골반환 손상에 동반될 수 있으나 매우 드문 것으로 보고되고 있다. 이 경우 고환의 탈구로 인한 통증을 환자가 호소하여도 골반환 손상에 의한 통증으로 간과되기가 쉽다. 고환 탈구가 조기에 진단되지 않아 치료가 지연되면 고환 괴사 등과 같은 합병증으로 이어질 수 있어 주의를 요한다. 본 저자들은 골반환 손상에 동반된 고환 탈구환자를 경험하여 이에 대한 증례보고를 하고자 한다. Unstable pelvis ring trauma can accompany urologic injuries such as bladder, ureter, or urethral injuries. In very rare cases, testicular dislocation can accompany a pelvic ring injury. Testicular dislocation causes pain, but can be regarded as the pain caused by pelvic ring injury. If not detected early, testicular dislocation may result in gangrenous testes. The authors report a case of pelvic ring injury with testicular dislocation.