• Clinics in Shoulder and Elbow
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• v.2 no.1
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• pp.14-20
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• 1999

Purpose: Despite of the popular use of the reconstruction plate for the fixation of clavicular shaft fractures, some disadventages have been raised such as long period of immobilization, long skin incision, loosening of plate and screws, and increased chance of nonunion due to severe periosteal injury. Thus, the authors have performed intramedullary multiple Steinmann pins fixation that could reduce the disadvantages of plate fixation in order to compare the treatment results between the two groups. Materials & Methods: From 1994. Jan. to 1997. Dec. the department of orthopaedic surgery of the Kwak's hospital treated operatively for 56 cases of the clavicular shaft fractures in adult. 39 cases of them were treated with the plate fixation and 17 cases with the intramedullary multiple Steinmann pins fixation(SP group). Reconstruction plates(Plate group) were used for 26 out of 39 patients treated with plate fixation. Among the Plate group and SP group, each 15 cases were selected by age and sex and compared each other according to the bone union time, union rate, complication, and functional results. The follow-up period was 12 months at the shortest and 48 months at the longest and the average was 16 months. Results: The Plate group showed that the bone union time was 7 weeks and the bone union rate was 93%. The SP group showed 6.5 weeks and 100% respectively. In complication, the Plate group had 1 case of loosening of plate and screws and delayed union; SP group had 1 case of pin migration. The functional results according to Kang's criteria, 87% of the Plate group and 93% of the SP group showed good or excellent. Conclusion : The SP group showed very comparable results in terms of the bone union time, bone union rate, complication, and functional results comparing to the Plate group. The intramedullary multiple Steinmann pins fixation showed several advantages over the reconstruction plate fixation, which were simple operative technique, easy removal of pins, being able to perform immediate postoperative full range of motion exercise. Therefore, the intramedullary multiple Steinmann pins fixation is thought to be one of the useful operative techniques in treatment of the clavicular shaft fractures in adult.

• Korean Journal of Ichthyology
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• v.1 no.1_2
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• pp.24-34
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• 1989

We reexamined the skulls of 14 gobionine genera of Korea to study taxonomic status of Gobioninae. The character transformation series found in the morphology of urohyal was very distinct among other skeletal characters. The gobioninae fishes of Korea were divided into 4 groups based on their morphology of urohyal as follows ; 1. Coreoleuciscus, Gnathopogon group ; The horizontal plate of urohyal has a ellipse shape with posterior edge wedged and the length is longer than that of vertical plate. 2. Hemibarbus, Squalidus group ; The horizontal plate has a elongated rhombeus shape with posterior edge pointed and the length is shorter than that of vertical plate. 3. Sarcocheilichthys, Pseudopungtungia, Pseudorasbora, Pungtungia group ; the horizontal plate has a expanded rhombeus shape, the length is longer than that of vertical plate, the hypohyal attatchment is not bifurcated, and the profile of the horizontal and vertical plate curved ventrally. 4. Ladislavia, Gobiobotia, Abbottina, Hicrophysogobio, Pseudogobio, Saurogobio group ; The horizontal plate has a pin or wedge shape expanded anteriorly, the length is shorter than that of vertical plate, and the hypohyal attatchment is thickened laterally. This results agreed with those by the adductor mandibulae complex, the geniohyoideus of cephalic muscles, and the cephalic-lateral line canals.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.2
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• pp.37-46
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• 2009

In this study, the seismic performance of the Buckling Restrained Knee Bracing (BRKB) system was evaluated through a pin-connected 1-bay 1-story frame. The BRKB system using a bolted channel section developed was composed of a steel plate as a load-resisting core member and two channel sections as a restrainment of the local and global buckling of the core plate. The main purpose of the BRKB system is to be used as an effective tool to re-strengthen/rehabilitate old low- and mid-rise RC frame buildings, which do not have enough seismic resistance to earthquake loadings. The main variables for the test specimens were the size of the core plates, stiffeners and the use of guide plates. The test results showed that the size of the core plate, which was the main element for the load-resisting member, was the most important parameter to achieve ductile behavior under tension as well as compression, until the maximum displacement exceed twice the design drift limit given by the AISC Seismic Provisions.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.105.2-105.2
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• 2011

화비정질 실리콘의 빛에 의한 노화현상 (light-induced degradation; LID)은 이미 1977년 보고된 Staebler-Wronski 효과에 의해서 확인된 바 있다. 이는 비정질 실리콘이 빛에 노출될 때, 이미 포함되어 있는 수소원자가 빛 에너지에 의해서 이동하게 되고, 이로 인해서 생성 또는 소멸되는 댕글링 본드 때문에 일어난다. 특히, 일상적인 태양광의 노출 하에서 태양전지의 장시간 성능을 예측하는데 물리적인 이해의 부족 및 기술 환경적인 어려움이 있고, 이러한 요인들은 안정된 태양전지를 개발하는데 장해요인으로 나타난다. 그러므로 비정질 실리콘 태양전지가 장시간 태양광에 노출되어 시간이 지남에 따라서 "성능이 어떻게 변하는지?" 그리고 "이에 대한 원인은 무엇인지?" 등은 여전히 과학적으로 풀어야할 숙제로 남아있다. 본 논문에서는 비정질 실리콘으로 구성된 태양전지가 태양광에 노출될 때 시간이 지남에 따라서 (1) 성능이 어떻게 변하는지, (2) LID의 변화는 언제 안정화되는지, 그리고 (3) 성능변화에 대한 원인은 무엇인지에 대해서 논의한다. 본 논문은 장시간 빛에 노출되는 비정질 실리콘 태양전지의 성능예측에 관해서 연구하였다. 결함밀도의 운동학적 모형을 통해서 태양광 노출에 대한 태양전지 성능변화를 예측하는데 초점을 맞추었고, 이를 위해서 태양전지에 조사되는 태양광 세기, 주변온도, 등이 고려되었다. 특히, 전하운반자의 수명이 결함밀도에 의해서 결정되기 때문에 비정질 실리콘 태양전지의 빛에 대한 노화현상 (LID)이 확장지수함수 (stretched-exponential) 완화법칙을 따르는 결함밀도에 의해서 물리적으로 설명된다. 한편 이와 같은 물리적 계산의 유용성을 확인하기 위해서 동일한 태양전지에 대해서 AMPS-1D 컴퓨터 프로그램을 사용하였고, 이를 통해서 비정질 실리콘 태양전지의 빛에 대한 노화현상을 물리적 및 정량적으로 이해하였다. 본 연구에 적용되는 태양전지는 비정질 실리콘으로 구성된 pin 구조 (glass/$SnO_2$/a-SiC:H:B/a-Si:H/a-Si:H:P/ITO)로서 다음과 같은 특성을 갖는다: 에너지 띠간격~1.72 eV, 두께~400 nm, 내부전위~1.05 V, 초기 fill factor~0.71, 초기 단락전류~16.4 mA/$cm^2$, 초기 개방전압 0.90 V, 초기 변환효율 10.6 %. 우리는 이와 같은 연구를 통해서 과학적으로 비정질 실리콘의 빛에 의한 노화현상을 이해하고, 기술적으로 효율 및 경제성이 높은 태양전지의 개발에 도전한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.15-20
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• 2018

The objective of this study is to numerically investigate the thermal characteristics of an automobile exhaust-based heat exchanger for automotive thermoelectric power generation with various exhaust gas mass flow rates and temperatures. The heat exchanger for automotive thermoelectric power generation has a square-type pin installed inside, so the maximum amount of heat can be transferred to the thermoelectric element from the heat energy coming from the automobile exhaust gas. The exhaust gas mass flow rate changed from 0.01, to 0.02, to 0.03 kg/s, and the exhaust gas temperature changed from 400, to 450, to 500, to 550, to $600^{\circ}C$, respectively. A numerical simulation was conducted by using the commercial program ANSYS CFX v17.0. Consequently, the exhaust gas pressure difference between the inlet and the outlet of the heat exchanger is determined according to the flow rate of the exhaust gas. When the mass flow rate of the exhaust gas increased, the pressure difference between the inlet and the outlet of the heat exchanger increased, but the exhaust gas pressure difference between the inlet of the heat exchanger and the outlet did not vary with the exhaust gas temperature. Therefore, in order to obtain the maximum surface temperature from the heat exchanger, the exhaust gas mass flow rate should be lower, and the exhaust gas temperature should be higher.

• The KIPS Transactions:PartB
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• v.9B no.2
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• pp.245-254
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• 2002

IC package marking inspection system using machine vision locates and identifies the target elements from input image, and decides the quality of marking by comparing the extracted target elements with the standard patterns. This paper proposes an adaptive multi-level thresholding (AMLT) method which is suitable for a series of operations such as locating the target IC package, extracting the characters, and detecting the Pinl dimple. It also proposes a dynamic matching unit selection (DMUS) method which is robust to noises as well as effective to catch out the local marking errors. The main idea of the AMLT method is to restrict the inputs of Otsu's thresholding algorithm within a specified area and a partial range of gray values. Doing so, it can adapt to the specific domain. The DMUS method dynamically selects the matching unit according to the result of character extraction and layout analysis. Therefore, in spite of the various erroneous situation occurred in the process of character extraction and layout analysis, it can select minimal matching unit in any environment. In an experiment with 280 IC package images of eight types, the correct extracting rate of IC package and Pinl dimple was 100% and the correct decision rate of marking quality was 98.8%. This result shows that the proposed methods are effective to IC package marking inspection.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.11
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• pp.1-5
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• 2010

We developed a novel micro-electro mechanical systems (MEMS) test socket using silicon on insulator (SOI) substrate with the cantilever array structure. We designed the round shaped cantilevers with the maximum length of $350{\mu}m$, the maximum width of $200{\mu}m$ and the thickness of $10{\mu}m$ for $650{\mu}m$ pitch for 8 mm x 8 mm area and 121 balls square ball grid array (BGA) packages. The MEMS test socket was fabricated by MEMS technology using metal lift off process and deep reactive ion etching (DRIE) silicon etcher and so on. The MEMS test socket has a simple structure, low production cost, fine pitch, high pin count and rapid prototyping. We verified the performances of the MEMS test sockets such as deflection as a function of the applied force, path resistance between the cantilever and the metal pad and the contact resistance. Fabricated cantilever has 1.3 gf (gram force) at $90{\mu}m$ deflection. Total path resistance was less than $17{\Omega}$. The contact resistance was approximately from 0.7 to $0.75{\Omega}$ for all cantilevers. Therefore the test socket is suitable for BGA integrated circuit (IC) packages tests.

• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.603-610
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• 2006

The external unbonded strengthening offers advantages in speed and simplicity of installation over other strengthening techniques. Unlike externally bonded steel plate or carbon fiber sheet, surface preparation of the concrete for installation of high-tension bar is not required and installation is not affected by environmental conditions. Anchoring pin or anchoring plate are installed at the end of beam to connect the high-tension bar to concrete beam. The deviator are used in order that supplementary external bars would follow the curvature of the tested beam. A set often laboratory tests on reinforced concrete beam strengthened using the technique are reported. The main test parameters are the section area of strengthening bar, the depth of deviator and the number of deviators. The paper provides a general description of structural behavior of beams strengthened using the technique. The test result of strengthened beam are compared with those from a reference specimen. It is shown that the reinforcing technique can provide greater strength enhancements to unstrengthened beam and that the provision of deviator enhances efficiency. The ultimate moment of specimen with two deviators was higher than that of specimens with one deviator. It is also shown that the external bars enhance strength of beams in shear.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.4
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• pp.746-757
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• 1996

Bony defects may be found as a result of congenital anomalies, traumatic injury, automobile collisions and industrial accidents in the maxillofacial area. Such conditions are often associated with severs functional and esthetic problem. Various surgical procedure has been utilized in attempts to repair and reconstruct bony defects. Bone is a complex, living, constantly changing tissue. The architecture and composition of cancellous and cortical bone allow the skeleton to perform its essential mechanical functions. Periosteum covers the external surface of bone and consists of two layers : an outer fibrous layer and an inner more cellular and vascular layer. The inner osteogenic layer or cambium layer can form new bone while the outer layer firms part of the insertions of tendons, ligaments and muscles. This study was under taken to evaluate bone healing process on partial defect of calvarial bone with or without periosteum in rat. We made calvarial defects of different size(4mm, 6mm, 8mm) with periosteum or without periosteum in rat to study the effect of defect size on healing process. Control and experimental groups sacrified at 1, 2, 4, 6, 8 weeks, postoperatively. We examed the specimens by gloss findings, light microscophy, and fluorescent microscophy. The results were as follows. 1. Gloss findings: Control groups are larger bony defects than experimental groups after 2 weeks, and than control groups advanced healing of defected bone but experimental groups are lesser after 4, 6 weeks. After 8 weeks, bone defect has not been identified in control and experimental groups. 2. Light microscope: All defects of control groups are larger bony defects than experimental groups after 2 weeks. And than control groups show smaller defect after 4 weeks. After 8 weeks, the control group reveal pin-point sized, hardly identifiable defect space and the experimental group reveal small, but definite defect space. 3. Fluorescent microscope : Each week, new bone formation of control group is very similar to the experimental group. In this study, Osteogenesis of calvarial bone defects with periosteum or without periosteum was examined for 8 weeks in rats. The replaced periosteum had batter new bone formation than the removed periosteum.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.7
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• pp.635-645
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• 2016

In this paper, we showed the phase noise of voltage controlled oscillator(VCO) can be radically improved using FLL(Frequency Locked Loop). At first, a 5 GHz VCO is fabricated using a hair-pin resonator. The fabricated VCO shows a phase noise of -53.1 dBc/Hz at 1 kHz frequency offset. In order to improve the phase noise of the fabricated VCO, a FLL is constructed using the feedback loop that consists of the VCO, a frequency detector composed of 5 GHz resonator, loop-filter, and level shifter. The fabricated FLL is designed to oscillate at a frequency of 5 GHz, and its measured phase noise is about -120.6 dBc/Hz at 1 kHz offset frequency. As a result, the phase noise of VCO can be radically improved by about 67.5 dB applying FLL. In addition, the measured phase noise performance is close to that of crystal oscillator.