• Journal of Korean Medicine Rehabilitation
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• v.19 no.2
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• pp.203-212
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• 2009

Objectives : Spurling test is one of the most widely used physical tests to diagnose herniated cervical intervertebral disc. The purpose of this study is to analyse diagnostic validity of Spurling test. Methods : This study was carried out on 382 subjects who visited Bu-Chun Ja-Seng oriental hospital with the neck pain or radiating pain from neck to upper extremities from November, 2007 to October, 2008. All subjects underwent both Spurling test and cervical magnetic resonance imaging(MRI). The associations between Spurling test and herniated cervical intervertebral disc were analysed. Results : 1. The sensitivity of Spurling test for herniated cervical intervertebral disc was 64%. 2. The specificity of Spurling test for herniated cervical intervertebral disc was 86%. 3. The positive predictive value of Spurling test for herniated cervical intervertebral disc was 93%. 4. The negative predictive value of Spurling test for herniated cervical intervertebral disc was 44%. Conclusions : This study suggests that Spurling test is not useful in screening for herniated cervical intervertebral disc due to the test's relatively low sensitivity. Thus it is necessary to consult advanced tests such as diagnostic imaging to diagnose herniated cervical intervertebral disc.

• Journal of Korean Medicine Rehabilitation
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• v.23 no.2
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• pp.129-138
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• 2013

Objectives : This study investigated the relationship between straight leg raising(SLR), valsalva test and size, position of lumbar disc herniation. Methods : We took SLR and valsalva test on 105 patients with lumbar disc herniation. According to the result of MRI findings, this study classified three groups of 105 patients with lumbar disc herniation, bulging, protrusion and extrusion. According to the position of lumbar disc herniation, 72 patients that were diagnosed protrusion and extrsuion were sorted 4 groups, lateral, lateral postero-lateral, central postero-lateral, central. The association size, position of lumbar disc herniation and SLR, valsalva test were analysed. Results : The bigger size of disc herniation, the more positive result of SLR and valsalva test, the lower angle of SLR test. There was not significant association between the position of lumbar disc herniation and the angle of SLR test. Conclusions : The SLR and valsalva test is an useful physical examination to speculate about the degree of lumbar disc herniation.

• Journal of Korean Neurosurgical Society
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• v.38 no.3
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• pp.196-201
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• 2005

Objective : Among upper lumbar disc herniations, L1-2 disc herniations are especially rare. We present the specific clinical features of L1-2 disc herniation and compared results of different surgical options. Methods : The authors undertook a retrospective single institution review of the patients who underwent surgery for L1-2 disc herniation. Thirty patients who underwent surgery for isolated L1-2 disc herniations were included. Results : Buttock pain was more frequent than anterior or anterolateral thigh pain. Standing and/or walking intolerance was more common than sitting intolerance. The straight leg raising test was positive only in 15 patients [50%]. Iliopsoas weakness was more frequent than quadriceps weakness. Percutaneous discectomy group demonstrated worse outcome than laminectomy group or lateral retroperitoneal approach group. Conclusion : Standing and/or walking intolerance, positive femoral nerve stretch test, and iliopsoas weakness can be useful clues to the diagnosis of L1-2 disc herniation. Posterior approach using partial laminectomy and medial facetectomy or minimally invasive lateral retroperitoneal approach seems like a better surgical option for L1-2 disc herniation than percutaneous endoscopic discectomy.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.1
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• pp.67-76
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• 1998

Friction materials for brake linings and clutches have severe performance requirements. The principal function of such frictional elements is to convert kinetic energy to heat, and then either to absorb or to dissipate heat. In order to achieve these objectives, the coefficient of friction must be as high as possible, independent of variations in operating conditions, and the necessary energy conversion must be accomplished with a minimum of wear on the contacting parts. In this study, Al powder, Al bronze powder and Mo powder used in general for automobile brake was sprayed on automobile brake disc to restrain rust and to maintain friction performance. Dynamo and corrosion tests have been carried out. It is concluded that the sprayed disc with Al bronze powder has the most improved frictional performance and anti-corrosive characteristics. The main results obtained can be summarized as follows; 1. From the corrosion current density test for gray cast iron and sprayed disc with powders of Al, Al bronze and Mo, it was cleared that the spray treatment with Al bronze powder showed the most superior anti-corrosive characteristics than other powders. 2. By anode polarization toward the noble direction from corrosion potential, corrosion current density with sprayed brake disc by Al-bronze powder was the lowest. 3. Mean frictional coefficients obtained from dynamo test are as follows : the sprayed disc with Al(99.99%) powder was 0.190 ; the sprayed disc with Al-bronze powder was 0.312 ; the sprayed disc with Mo powder was 0.257 ; the non-sprayed disc of gray cast iron was 0.331. In the case of the sprayed disc Al-bronze powder showed the most excellent frictional characteristics . 4. Amount of burnish quantity obtained from burnish test by dynamometer is as follows : the sprayed disc with Al-powder was 1.079 mm : the sprayed disc with Al-bronze powder was 0.155 mm : the sprayed disc with Mo powder was 0.253 mm : the non-sprayed disc of gray cast iron was 0.241 mm. Al-bronze powder also showed the most excellent burnish characteristics.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.615-620
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• 2010

During braking of railway vehicles the repetitive thermal shock leads to thermal cracks on disc surface, and the lifetime of brake disc is dependent on the number of trimming works for removing these thermal cracks. Many tries for development of high heat resistant brake disc to extend the disc life and to warrant reliable braking performance has been continued. In present study, we carry out the computational fatigue analysis for thermal fatigue test in three candidate materials which were made to develop new high heat resistant material. Using FEM, we simulate thermal fatigue test in three candidate materials and conventional disc material. We then estimate the number of cycle to thermal crack initiation based on data from mechanical fatigue tests, and the results are compared with each material. For each material, the correction factor for $N_{f-40}$ which is the number of cycles when crack over $40{\mu}m$ was observed in thermal fatigue test is decided. From this study, we can verify the performance of thermal fatigue test system and suggest a qualitatively comparative method for heat resistance by FEM analysis of thermal shocking phenomenon.

• Journal of Korean Medicine Rehabilitation
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• v.23 no.4
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• pp.159-167
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• 2013

Objectives In this study, we wanted to find out the characteristics - gender, SLR test, valsalva test, duration, ESR, CRP and night pain - of lumbar disc herniation being classified as blood stasis and phlegm-retained fluid. Methods We surveyed 42 patients suffering from lumbar disc herniation using the diagnosis blood stasis syndrome, water retention syndrome of the comprehensive diagnosis of QI blood water. Blood stasis and phlegm-retained fluid are identical with blood stasis syndrome, water retention syndrome. Then we analyzed the characteristics - gender, SLR test, valsalva test, duration, ESR, CRP and night pain - of the patients suffering from lumbar disc herniation who were diagnosed as blood stasis and phlegm-retained fluid. Results Patients were sorted into two groups: 18 blood stasis patients and 30 phlegm-retained fluid patients. Gender (Woman), acute phase and night pain are related to blood stasis. Acute phase, positive of SLR test is related to phlegm-retained fluid. There was no correlation between blood stasis and SLR test, valsalva test, duration, ESR, CRP. Also no correlation between phlegm-fluid and gender, valsalva test, duration, ESR, CRP and night pain. Conclusions By Considering the characteristics - gender, SLR test, valsalva test, duration, ESR, CRP and night pain - of lumbar disc herniation patients, it can help to analyze the pattern of its symptoms.

• Journal of Korean Medicine Rehabilitation
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• v.15 no.2
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• pp.67-75
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• 2005

Objectives : Straight leg raising test(SLR) is useful clinical test to diagnose herniated lumbar intervertebral disc. The purpose of this study is to analyse diagnostic value of straight leg raising test between traffic accident patients group and non-traffic accident patients group. Methods : The study involved 26 traffic accident patients group and 45 non-traffic accident patients group with low back pain or radiating pain into the leg. All had a result of straight leg raising test and lumbar computed tomography(CT) or magnetic resonance imaging(MRI). The associations between straight leg raising test and herniated lumbar intervertebral disc were analysed. Results and Conclusions : 1. There is not significant associations between straight leg raising test and herniated lumbar intervertebral disc in traffic accident patients group. 2. There is significant associations between straight leg raising test and herniated lumbar intervertebral disc in non-traffic accident patients group. 3. In traffic accident patients group, and negative predictive value are higher than non-traffic accident patients group. 4. In non-traffic accident patients group, sensitivity, positive predictive value and odds ratios are higher than traffic accident patients-group.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.580-585
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• 2003

Korean high speed train (KHST) has adopted a combined electric/ mechanic (friction) braking system. Electric brakes are consist of rheostatic brake, regenerative brake and eddy current brake and mechanical brakes are composed of disc brake, wheel disc brake and tread brake. In this paper, we introduce the braking performance test and the measuring method of mechanical brake. And disc brake performance has been reviewed by the experimental method. The on-line test of KHST has been carried out up to 260 km/h and proved that the disc braking capacity of KHST is sufficient.

• Tribology and Lubricants
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• v.18 no.4
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• pp.305-311
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• 2002

Three different kinds of brake discs including two coated brake discs and one steel disc were tested under the same experimental conditions on a reduced scale braking test bench. A braking test bench was specially designed to analyse thermo-mechanical and frictional behaviors of two types of brake with different sizes in stop and hold braking modes. Plasma spray coating technique was also used to coat the discs with ceramic powder. During the test four commercial brake pads were coupled with discs. Ceramic coated discs showed good stability in friction coefficient at high speed and high energy braking conditions. But they caused large wear loss of pad mass compared with the steel disc. It was shown that thermal barrier effect in ceramic coated discs adjusted the thermal partition between pad and disc. For a steel disc. it showed fluctuating friction coefficient at high speed but small wear loss of pad mass compared with ceramic coated discs.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.666-669
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• 2011

The rupture disc shapes of bulkhead type pulse separation device(PSD) are designed for new dual pulse rocket motor. Before final design PSD, that three different rupture disc are tested and confirmed the performance of the discs. Through analyzing the test results the PSD decides, two rupture disc shapes with flow holes of eight circles and eight trapezoids.