• Journal of the korean Society of Automotive Engineers
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• v.12 no.6
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• pp.3-10
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• 1990

본 고에서는 자동차용 수동변속기에 사용되는 평치차 및 헬리컬 치차에 대해서 설계조건과 설계절차 및 방법에 관해서 논하고자 한다. 자동차용 변속기의 치차 설계자는 gear box내의 좁은 공간에서 가장 정숙하고 튼튼하고, 소형.경량화된 치차를 설계하기 위해서는 module, 공구압력각, 치높이, 치선원경 등이 표준에서 벗어나는 특수 cutter를 이용하여 제작되도록 치차 설계를 할 수 밖에 없으나 자동차용 치차가 대량 생산되는 점에 비추어 볼때 특수 cutter를 사용하는데 드는 비용은 문제가 되지 않는다고 본다.

• Journal of Korean Foot and Ankle Society
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• v.11 no.2
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• pp.145-148
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• 2007

Purpose: This retrospective study was designed to evaluate the appearances of plantar fasciitis by ultrasonography. Materials and Methods: 48 cases of unilateral plantar fasciitis were enrolled in this study. Plain radiograph and realtime sonography of both feet were perfomred and the results were compared between the affected feet and controlateral symptomless feet. Calcaneal spur were observed on plain radiograph and thickness of plantar fascia, hypoechogenecity, blurring of border of plantar fascia, perifascial effusion, wavy plantar fascia were observed on sonography. Results: Women (35 cases) and left feet (30 cases) were more frequent than men and right feet. Thickness of plantar fascia in affected site was thicker than normal site (p<0.01). Hypoechogenecity was observed only in 39 cases (81%) affected site, blurring of border of plantar fascia in affected site was 30 cases (62%) and 7 cases (15%) in normal site, perifascial effusion was observed only in 38 cases (79%) affected site, wavy plantar fascia in affected site was 43 cases (90%) and 2 cases (4%) in normal site. Calcaneal spur in affected site was 36 cases (75%) and 33 cases (69%) in normal site. Conclusion: Sonography is a useful diagnostic procedure for the plantar fasciitis especially in the unilateral plantar fasciitis.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.4
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• pp.437-442
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• 2014

Recently, the needs for the development and application of the micro marine robot (MMR) which has the advantages in terms of size and cost are increasing. However, the basis is very short in the domestic. While the obstacle avoidance sonar (OAS) which was optimized in terms of size and performance and has the ability of 4-directional detection was developed for the obstacle avoidance of the micro surface robot (MSR) fortunately, the problem that the detection performance is degraded according to the shape of the obstacle because of using the fixed sonar-beam with the limited beam width and detection range exists. To solve this problem, the MSR mechanism that implements the rotating sonar-beam using the spur gear and the servo motor is proposed in this paper. To verify the performance of the proposed mechanism, the wall-tracking of the MSR is considered and the comparison and analysis in term of detection performance and actuation command is performed with conventional fixed sonar-beam. The test results show the validity of the proposed mechanism.

• Journal of Korean Neurosurgical Society
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• v.30 no.5
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• pp.600-604
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• 2001

Objective : The authors report the microsurgical anterolateral tunnel approach for the treatment of the cervical disc diseases and its postoperative surgical results. Methods : All surgical procedures followed the method of classical microsurgical anterior discectomy. Small tunnel(7-8mm) was made on the disc space reaching to the posterior longitudinal ligament. The disc materials and bony spurs were removed through this tunnel. Thirty-one patients of cervical disc herniation(24 cases with pure disc herniation, 7 cases with combined cervical spondylosis) were evaluated on the symptoms, conformation in plain X-ray, C-T, and MRI. The follow up time was over 2 years. Results : Postoperatively the result(following the out come scale) was excellent and good in Twenty-nine patients. One with fair result showed remnant disc particle and spur and another one is combined with cord contusion. One patient with lesion in C 3-4 space and two cervicothoracic junction showed excellent result. Two patients with osteoporosis also showed good results. Cervical spine curvature and disc space height were not changed on the plain X-ray and MRI in all patients. Twenty-nine patients were discharged within 3 days after surgery without any postoperative complications. Conclusions : The microsurgical anterolateral tunnel approach could be indicated for the treatment of patients with cervical disc diseases and with difficulty in achieving interbody fusion(the higher cervical level and cervicothoracic junction, osteoporosis etc.).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.9
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• pp.1005-1012
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• 2014

Gears are critical elements in automobiles, and their use as power transmitting machine elements in engineering applications is quite extensive. In the areas of contact between gear teeth, the condition of a gear is likely to deteriorate due to contact fatigue, wear, material defects, lubrication failure, etc. Thus, it is necessary to monitor its condition to ensure smooth power transmission. Gear teeth deterioration causes failures such as abrasive wear, scuffing, pitting, and spalling. These failures lead to a higher level of vibration signals in the gear system. This paper presents the results of an experiment on the surface fatigue wear of a spur gear system. The correlation between the estimated specific film thickness, statistical parameter of the vibration signals, and Stribeck curve was considered in this study.

• Korean Journal of Plant Resources
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• v.23 no.6
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• pp.541-549
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• 2010

The present study researched morphological characteristics and analyzed the genetic diversity by using RAPD in Calanthe species, native plant in Jeju, Korea. Twenty-six samples were selected by flower color, and 19 horticultural traits were investigated to study morphological characteristics. The C. discolor had the smallest leaf, the length and width of dorsal sepal, lateral sepal, petal, central lip, lateral lip, and flower stalk length were shortest and/or smallest except the spur and ovary length in Calanthe species, but those of Calanthe discolor for. sieboldii (Dence.) Ohwi (Calanthe discolor for. sieboldii) were the largest and/or biggest, and those of variants were the intermediate between C. discolor and C. discolor for. sieboldii, but spur length was the longest in C. discolor, the shortest in C. discolor for. sieboldii, and intermediate in the variants. Ovary length in C. discolor was shortest and C. discolor for. sieboldii and variants were similar with each other. The flower colors of C. discolor were brownish red, the value of CIE Lab was between 40 and 50. The flower color of C. discolor for. sieboldii was yellowish; the value of CIE Lab was between 110 and 130. And variants had various colors between 50 and 70 in the value of CIE Lab. After analyzing multiple band patterns of PCR products, 154 bands were selected as polymorphic RAPD markers. The analysis of Genetic distance of Calanthe species using RAPD showed that C. discolor and C. discolor for. sieboldii are more distant from each other than variants, and demonstrated the fact that genetic position of variants is between the other two species.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.4
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• pp.37-44
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• 2009

A novel phase-locked loop(PLL) architecture with resistance and capacitance scaling scheme has been proposed. The proposed PLL has three charge pumps. The effective capacitance and resistance of the loop filter can be scaled up/down according to the locking status by controlling the direction and magnitude of each charge pump current. This architecture makes it possible to have a narrow bandwidth and low resistance in the loop filter, which improves phase noise and reference spur characteristics. It has been fabricated with a 3.3V $0.35{\mu}m$ CMOS process. The measured locking time is $25{\mu}s$ with the measured phase noise of -105.37 dBc/Hz @1MHz and the reference spur of -50dBc at 851.2MHz output frequency

• Journal of Korean Foot and Ankle Society
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• v.17 no.2
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• pp.121-129
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• 2013

Purpose: To evaluate the radiographic characteristics of the tarsometatarsal osteoarthritis with hallux valgus deformity and report the clinical results of the operative treatment. Materials and Methods: This is a retrospective study of 20 patients, 22 feet who had been operated for non-traumatic tarsometatarsal osteoarthritis with hallux valgus (TMT group) and control group of hallux valgus patients without tarsometatarsal osteoarthritis (26 patients, 28 feet) from April 2004 to July 2011. Radiographic characteristics were compared between the groups, using hallux valgus angle, $1^{st}-2^{nd}$ intermetatarsal angle, metatarsal length ratio, metatarsus adductus angle, talonavicular coverage angle, talus-$1^{st}$ metatarsal angle, calcaneal pitch angle and medial cuneiform height. Pre- and postoperative difference of $1^{st}-2^{nd}$ metatarsal declination angle and distance between the $1^{st}-2^{nd}$ metatarsal head were evaluated. The clinical results were evaluated by American Orthopaedics Foot and Ankle Society (AOFAS) midfoot scale and visual analogue scale (VAS). Results: Metatarsal length ratio was significantly larger in TMT group (p<0.001). Metatarsus adductus angle, talonavicular coverage angle, talus-$1^{st}$ metatarsal angle on lateral radiograph, calcaneal pitch angle and medial cuneiform height were different from control group (p<0.001, p<0.001, p=0.001, p=0.010, p=0.006). Postoperative declination of the $2^{nd}$ metatarsal and distance between the $1^{st}-2^{nd}$ metatarsal head were increased (p=0.009, p=0.001). The AOFAS and VAS score were improved (p<0.001, p<0.001). Conclusion: Non-traumatic osteoarthritis of the tarsometatarsal joints seems to be associated with long 2nd metatarsal length, metatarsus adductus and flatfoot deformity. Spur excision may be successful to relieve symptoms when the arthritis was diagnosed in early stage.

• Journal of Korean Foot and Ankle Society
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• v.17 no.2
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• pp.100-105
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• 2013

Purpose: To present radiographic characteristics and report the clinical results of the operative treatment of M$\ddot{u}$ller-Weiss disease. Materials and Methods: This is a retrospective study including 13 patients, 14 feet who had been operated for M$\ddot{u}$ller-Weiss disease between April 2006 and December 2011. Osteoarthritis of the peri-navicular joints were radiographically evaluated. Various range of peri-navicular fusion and joint-preserving surgeries according to patients' symptoms and radiographic findings were done. The clinical results were evaluated by American Orthopaedics Foot and Ankle Society (AOFAS) midfoot scale and visual analogue scale (VAS). Results: On radiographs, osteoarthritic changes were presented at talonavicular joint in 11 cases, calcaneocuboid joint in 7 cases, subtalar joint in 6 cases, naviculo-cuneiform joint in 1 case. The mean anteroposterior talocalcaneal angle was 16.6 degrees. On hindfoot alignment view, 6 cases were varus, 5 cases were neutral and 3 cases were valgus alignment. Fusion comprised 6 cases in triple fusion, 1 case in talonavicular-cuneiform fusion, 2 cases in talonavicualr fusion and 1 case in talonavicular & calcaneocuboid fusion. Joint-preserving surgeries were bony fragment excision of the lateral part of navicular & medial displacement calcaneal osteotomy in 1 case, bony spur excision of talonavicular joint in 1 case and medial displacement calcaneal osteotomy in 2 cases. The postoperative AOFAS and VAS score were improved significantly (p=0.000, p=0.000). Conclusion: In cases of M$\ddot{u}$ller-Weiss disease without osteoarthritic changes at peri-navicular joints, fragment excision of navicular, bony spur excision with or without medial displacement calcaneal osteotomy were effective operative treatments.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.2
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• pp.1-6
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• 2010

This study presents the practical design modification to improve the retracting performance of the pyro-typed high power pretensioner. 3 components of the pretensioner are redesigned and the usefulness of the design modification is verified by the experiment. During the pretensioning process, the gas blast generated from the gunpowder is transferred to the rack-pinion gear through the manifold. The rack-pinion gear is connected with the spool where the webbing is rolled up. According to the rotation of the pinion, the spool is turned and the webbing is winded. To help the gas blast flow well, the shape of the inner cross section of the manifold is changed. The spur gear design program is developed and used to find the best combination of the rack-pinion gear pair to increase the power transmission efficiency. The pinion guide is installed on the spool to prevent the vibration of the pinion. As a result of the experiment, the amount of the web retraction length is increased when every single design modification is applied. Therefore, the retracting performance of the pretensioner is considered to be improved if the presented design modifications are applied.