• 소성∙가공
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• 제24권3호
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• pp.212-217
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• 2015

SmartCrown is a system to control the plate crown by shifting the sine-shaped work rolls in the axial direction. The control range of the plate crown depends on a depth of sine-shaped roll profile because the roll radius varies continuously along the axial direction. When the roll profile is changed to improve the control range, the contact stress between the work roll and the back-up roll also changes. In the current study, the contact stress for various profiles and rolling conditions were analyzed using the finite element method and compared with results from Hertzian contact theory. A submodel method is used to increase the accuracy of the finite element analysis. The analysis results showed that the maximum increase in the contact stress was only 53MPa, so it is anticipated that no back-up roll spalling will occur.

• Journal of Korean Neurosurgical Society
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• 제43권3호
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• pp.139-142
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• 2008

Objective: The purpose of this study was to evaluate the efficacy of spinal implant removal and to determine the possible mechanisms of pain relief. Methods: Fourteen patient~with an average of 42 years (from 22 to 67 years) were retrospectively evaluated. All patients had posterior spinal instrumentation and fusion, who later developed recurrent back pain or persistent back pain despite a solid fusion mass. Patients' clinical charts, operative notes, and preoperative x-rays were evaluated. Relief of pain was evaluated by the Visual Analog Scale (VAS) pain change after implant removal. Clinical outcome using VAS and modified MacNab's criteria was assessed on before implant removal, 1 month after implant removal and at the last clinical follow-up. Radiological analysis of sagittal alignment was also assessed. Results: Average follow-up period was 18 months (from 12 to 25 months). There were 4 patients who had persistent back pain at the surgical site and 10 patients who had recurrent back pain. The median time after the first fusion operation and the recurrence of pain was 6.5 months (from 3 to 13 months). All patients except one had palpation pain at operative site. The mean blood loss was less than 100ml and there were no major complications. The mean pain score before screw removal and at final follow up was 6.4 and 2.9, respectively (p<0.005). Thirteen of the 14 patients were graded as excellent and good according to modified MacNab's criteria. Overall 5.9 degrees of sagittal correction loss was observed at final follow up, but was not statistically significant. Conclusion: For the patients with persistent or recurrent back pain after spinal instrumentation, removal of the spinal implant may be safe and an efficient procedure for carefully selected patients who have palpation pain and are unresponsive to conservative treatment.

• The Journal of Korean Physical Therapy
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• 제33권2호
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• pp.97-105
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• 2021

Purpose: This study examined the effects of the application of Schroth exercise-based instrument Pilates exercise on the Cobb's angle, angle of trunk rotation, and low back pain of female patients with idiopathic scoliosis. Methods: Three patients with idiopathic scoliosis at a Cobb's angle of 20° or more participated in this study. Among the single-subject experimental research designs, a reversal (ABA) design was performed. In particular, Schroth exercise-based instrument, Pilates exercise, was performed for 10 weeks, consisting of five weeks between the baseline and intervention one period and five weeks between the intervention 1 and intervention 2 periods, and then followed up for five weeks. Results: After the Schroth exercise-based instrument, Pilates exercise, was applied, the Cobb's angle and the angle of trunk rotation decreased compared to the baseline in all subjects, and the follow-up period also showed a continuous decline. After Pilates exercise was performed, low back pain in subjects 1 and 2 was decreased in the intervention 1 period compared to the baseline. The level of low back pain in the intervention 2 period increased compared to the intervention 1 period, but a reduction was noted in the follow-up period. The low back pain in the subject was decreased in all intervention periods and the follow-up period. Conclusion: Schroth exercise-based Pilates exercise improves the Cobb's angle and the angle of trunk rotation for female patients with idiopathic scoliosis in their teens and 20s, and an effective intervention method is proposed for low back pain.

• Journal of Acupuncture Research
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• 제27권1호
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• pp.31-41
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• 2010

Objectives : The purpose of this study is to set up the standard for Classification and Diagnosis of Low Back Pain by through collecting bibliographic study on Low Back Pain and related general symptoms in classical literatures Methods : We investigated the contents of classical literatures about chronic low back pain and related general symptoms. With this contents, we established a systemic classification and diagnostic standard for Low back pain. Results : There are many different opinions on classification of low back pain and general symptoms in oriental medicine classical literature. Every opinion is reasonable, so it is difficult to establish a diagnosis of Low back pain. But it is necessary to set up the one-systemic classification and diagnostic technique of Low back pain. Conclusions : We conclude that the Ten type Low back pain classification of in Dong-Eui-Bo-Gam is a reasonable standard for diagnostic classification.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 제7회 압연 심포지엄
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• pp.62-64
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• 2009

Control of back-up roll deformation and wear profile in plate rolling is important not only for enhancement of the structural precision of mill, but also for improving the yield and rolling operation. in the heavy plate mill, there have been strong demands for upgrading back up roll operation technology. In order to satisfy these demands, it is essential to develop the backup roll deformation analysis models and wear profile prediction models. This paper gives a general description of the backup roll deformation and wear model, simulation result for deformation analysis and wear profile.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 1999년도 추계학술대회
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• pp.345-354
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• 1999

A new type of capacitor named "Super Capacitor" has been developed, in which the properties of electric double layer formed at the interface of activated carbon electrode- liquid organic electrolyte is applied. This capacitor is small In size, light in weight, wide In temperature range(-25~$70^{\circ}C$), large in charge-discharge capability and good in voltage preservation. And this super capacitor is applied as a power back-up for electricity failure in volatile memory devices etc., a power source for a short time and a power source for operating actuators. At present the development of high power back-up types of the capacitor system and improvement of their characteristics are being actively conducted in order to find wider applications.lications.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.842-844
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• 2004

The Back Up Breaker and Making Switch are very important equipments for the short circuit test facility, and contacts are the most important parts of the above switches. There are very many kind of contacts according to switches characteristic and should be done the verification test before use, especially development contacts. This study describes the class of switches, arc chute, material of whole contacts and essential test for verification. The essential test for verification are dielectric test, mechanical operation test, short-time withstand current test, load current breaking test, and short-circuit making current test etc.

• 한국자동차공학회논문집
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• 제21권4호
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• pp.153-158
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• 2013

The purpose of this study is to investigate the performance characteristics of the counterflow exhaust heat recovery device for the applied gasoline engines. The EHRS device is installed behind the catalyst. This study investigates the engine warm-up characteristic, the exhaust noise characteristic, the back-pressure characteristic. The engine warm-up characteristics is (load 0%, load 10%, load 20%) in (idle, 1000rpm, 1500rpm, 2000rpm, 2500rpm) conditions by measuring the time it warmed up, coolant temperature ($25^{\circ}C{\sim}80^{\circ}C$) until the performance evaluation is performed. The wide open throttle and the coast down the exhaust noise and the back-pressure characteristic experiment repeated twice. The test conditions is 950rpm~6,050rpm proceed experiment repeated 3-5 times. Load 0% idle conditions except the results improved engine warm-up characteristics. The exhaust noise obtain similar results the BASE+EHRS W/O_FRT_MUFF with BASE and back-pressure to obtain similar results BASE+EHRS W/O_FRT_ MUFF with BASE+EHRS.

• The Journal of Korean Physical Therapy
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• 제35권6호
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• pp.200-205
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• 2023

Purpose: The purpose of this study is to find out how gait training with shoulder-back assistive device affects dynamic and static balance, gait of patients with stroke and to help improve body alignment, balance, and gait ability in stroke patients. Methods: Measurements were taken of the 20 subjects before intervention without shoulder-back assistive device, after intervention with device, and follow up after an hour compared. Berg balance scale used to evaluate dynamic balance; wii balance board was used to measure static balance; and gait ability were measured by timed up and go test and 10-meter walk test. To analyze the results, a one-way repeated measures analysis of variance was implemented to compare the measurements. Results: The results showed that, after wearing the shoulder-back assistive device, the subjects' dynamic balance statistically significantly improved; no statistically significant difference was observed in static balance, although their balance ability was enhanced; and their increase in gait ability was statistically significant. Conclusion: This study proved that gait training combined with a shoulder-back assistive device positively impacted dynamic and static balance, gait of patients with stroke.

• 한국정보기술학회 영문논문지
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• 제9권2호
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• pp.75-87
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• 2019

This paper presents a fully digital controlled power supply unit for the wireless controlled dimmable LED lighting system. The proposed power supply designed using a fly-back converter, which is directly controlled by a microprocessor. Although the proposed circuit does not sense the AC input current and has not AC input voltage feed-forward, it can achieve a high power factor. The proposed power supply directly regulates the output power for LED loads using the PWM and PFM control of the fly-back converter without additional regulator. For a wireless remote control function, the Zigbee modem is equipped in the proposed power supply. A prototype set-up has been built and tested. Through the experiment with a prototype set-up, the usefulness of the proposed power supply is verified.