• Imaging Science in Dentistry
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• v.36 no.1
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• pp.17-24
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• 2006

Purpose : The objective of this study was to investigate the effect of TMJ disc displacement on the TMJ disc configuration and surrounding osseous structure. Materials and Methods : The proton density and 72-weighted MR images of 57 TMJs were retrospectively studied. These TMJs were divided into three groups according to the anterior disc displacement status on MR sagittal images, those were the normal, anterior disc displacement with reduction (ADWR), anterior disc displacement without reduction (ADWOR). The frequency of disc configuration and surrounding bony change, the border status between articular disc and retrodiscal tissue were investigated according to the positional change of articular disc. Results : There were significant statistical differences of chi-square statistics of TMJ disc configurational type between normal and ADWR/ADWOR group, respectively. Surrounding bony change frequently appeared in ADWOR and a statistically significant difference of chi-square statistics of bony change frequency between normal and ADWOR group was observed. Conclusion : These results suggested that the disc configuration and bony change of TMJ are strongly related to TMJ disc displacement.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1621-1626
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• 2003

This study deals with the heat transfer analysis on phase change optical disc with land/groove recording by means of numerical method. Finite difference time domain(FDTD) method was used to obtain the amount of absorption of light propagating inside disc and finite difference element(FEM) method was used to calculate the temperature distribution. The calculated results present the detailed information of recording characteristics on the phase change optical disc. The temperature profiles are quite different between the land track and the groove track. The recorded mark shape on land track is smaller and more elliptic than that on groove track. It is shown that the thermal problem to the neighboring track takes place due to secondary peaks. It is found that the different write strategy should be applied to land and groove recording, respectively.

• Journal of Korean Medicine Rehabilitation
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• v.19 no.3
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• pp.81-90
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• 2009

Objectives : To analyze the therapeutic outcomes of back pain modalities in patients with disc herniation according to the change of Magnetic Resonanse Imaging(MRI) whom were treated with herbal medicine, chuna, acupuncture, bee-venom acupuncture. Methods : Clinical outcomes of 35 patients diagnosed with lumbar disc herniation by MRI examination, treated conservatively, were analyzed according to MRI follow-up change. Patients underwent MRI examaintion at baseline and after 24th week of treatment. Patients are divided into three groups ; improved, unchanged, worsened. 35 patients with lumbar disc herniation were treated with chuna therapy, acupuncture, bee-venom acupuncture once a week and took herbal medicine after a meal two times daily. The patients' clinical outcomes were assessed at baseline, 12th week, 24th week by Visual analogue scale(VAS), Oswestry disability index(ODI). Results : 1. MRI follow-up exams on regression of disc herniation resulted on 42.86% of cases by conservative treatment. 2. VAS(low back pain and sciatica) and ODI of disability of daily activities showed significant decrease in "improved" and "unchanged" groups compared to "worsened" group(P<0.05). 3. VAS(low back pain and sciatica) and ODI change after treatment did not show any relationship with MRI follow-up change(P<0.05). Conclusions : This study suggests that "improved" and "unchanged" groups compared to "worsened" group on MRI follow-up in patients with lumbar disc herniation were more effective when treated with herbal medicine, chuna therapy, acupuncture, bee-venom acupuncture. MRI follow-up change does not affect clinical changes in patients with lumbar disc herniation.

• Journal of Oral Medicine and Pain
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• v.43 no.4
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• pp.142-146
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• 2018

Patients with temporomandibular disorder often present with acute occlusal change and properly managed with conservative treatment. If such change is caused by unusual etiology, differential diagnosis may be challenged. This article describes the diagnosis of a patient exhibiting pain and acute posterior open bite on the ipsilateral side after chewing hard food. After initial conservative treatment failed to resolve the complaint, magnetic resonance imaging was ordered and confirmed partial perforation of articular disc. Disc perforation itself is usually chronic in nature, but sudden macrotrauma may also cause the disorder. However, occlusal discrepancy caused by disc perforation is rare and seldom reported. We present a case of acute malocclusion caused by disc perforation with a review of related literature.

• Journal of Korean Medicine Rehabilitation
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• v.21 no.2
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• pp.253-263
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• 2011

Objectives : To analyze the therapeutic outcomes of back pain modalities in patients with disc herniation according to the change of magnetic imaging(MRI) at one year after conservative treatment. Methods : Clinical outcomes of 35 patients diagnosed with lumbar disc herniation by MRI examination, treated conservatively, were analyzed according to MRI follow-up change; improved, unchanged, worsened. Patients underwent MRI examination at baseline and after 24 week of treatment. After 1 year, we followed up 30 patients. The patients' clinical outcomes were assessed at baseline, 24 week, 1 year by visual analogue scale(VAS), oswestry disability index (ODI), and analyzed by each of it's correlation. Results : 1. VAS of sciatica and ODI of disability of daily activities showed significant decrease in patients after 1 year follow up(p<0.05). 2. VAS(low back pain and sciatica) and ODI of disability of daily activities showed significant decrease in "improved" group and VAS(sciatica) and ODI showed significant decrease in "unchanged" group. "worsened" group showed no statistic significance(p<0.05). 3. The 1 year follow-up of VAS(low back pain and sciatica) and ODI change showed relationship with MRI follow-up change(p<0.05). Conclusions : This study suggests that "improved" groups compared to "unchanged" and "worsened" group on MRI follow-up in patients with lumbar disc herniation were more effective at 1 year after conservative treatment. MRI follow-up change affect clinical changes in patients with lumbar disc herniation after 1 year.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.4
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• pp.337-343
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• 2001

Objective. Disc displacement may affect the joint space narrowing between condyle head and glenoid fossa. This study was designed to evaluate the correlation between the joint space change and the directions of disc displacement. Study Design. Two hundreds temporomandibular joints MR images of TMD patients (170 joints) and asymptomatic volunteers (30 joints) were evaluated for this purpose. Anterior disc displacement was divided into 3 stages (normal, little to mild, and moderate to severe displacement) based on sagittal images. And sideways displacement was classified as 3 categories (center, medial and lateral displacement) based on coronal images, then joint spaces were measured at medial, central and lateral parts of condyle head on coronal MR images, respectively. The joint spaces of 7 groups divided according to the severity and the direction of disc displacement were compared. Results. The reduction of the joint space was affected by sideways disc displacement at the opposite side of the condyle head, except the cases accompanied with severe anteriorly and laterally displaced disc. Conclusion. The sideways disc displacement affected on the opposite side temporomandibular joint space width.

• Journal of Acupuncture Research
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• v.19 no.6
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• pp.256-263
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• 2002

Objective : This study is to report the radiological change after bee venom therapy about the patient of sequestrated disc. Methods : there was a report that the bee venom therapy was effective treatment on the patient of extruded or sequestrated disc. So we treated the patient who was diagnosed as sequestrated disc and hospitalized, and investigated the change of DITI, simple X-rays and MRI before and after treatment. Results : There was remarkable improvement in condition of the patient who had extruded or sequestrated disc after treated by bee venom therapy. It showed that the region of sequestrated L4-5 dise remarkably decreased in MRI, degree of scoliosis decreased from 17 degree to 15 degree in simple X-ray and the difference of right and left became equal in DITI through the follow-up survey. Conclusions : There was reports that bee venom therapy had antinflammatory and antalgic effect and was effective in treating patient of sequestrated disc and in curing pain, functional disorder, and clinical symptom of HIVD patients by means of grade index of lumbago. We think that the result of this study will be supporting data (that will be able to) proves more objectively the change following the improvement of condition with radiological check.

• Transactions of the Society of Information Storage Systems
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• v.1 no.1
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• pp.34-41
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• 2005

We report some recent results in the rewritable Blu-ray Disc with enhanced overwrite cyclability by using the growth dominant eutectic based Ge(Sb70Te30)+Sb recording layer, GeN interface layer and write strategy optimization. We have developed phase-change optical media with appropriate write strategy for 36(i.e., 1X)-72Mbps(i.e., 2X) dual speed Blu-ray Disc system and fur the future high speed optical data storage. For recording layer, eutectic-based Ge(Sb70Te30)+Sb material was used and Sb/Te ratio and Ge content were optimized to obtain proper erasability and archival stability of recorded amorphous marks. The recording layer is wrapped up in GeN interface layers to obtain overwrite cyclability and higher crystallization speed. In addition, we designed appropriate write strategy so called Time-Shifted Multipulse (TSMP) write strategy where starting position of multipulse parts are shined from reference clock. With this write strategy, the jitter characteristics of the disc was improved and we found that leading edge jitter was improved much more than trailing edge jitter in 1X-2X speed recording. Finally, we investigated the higher speed feasibility of 144Mbps(i.e., 4X) by adopting some elemental doping to the eutectic based Ag-In-Sb-Te recording layer and structural optimization of constitution layers in Blu-ray Disc. In the paper, we report the effect of Sn addition for the feasibility of higher speed recording. The addition of Sn shows increases of the crystallization speed of phase change recording layer.

• Design & Manufacturing
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• v.16 no.1
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• pp.36-42
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• 2022

Globally, as population growth and economic development continue, resource consumption is increasing rapidly. As an alternative to electric vehicles was suggested as the environmental pollution problem emerged, the number of registered electric vehicles in Korea increased by more than 137 times compared to 2013. Secondary batteries are expected to expand into various markets such as small IT devices and electric vehicles, and the most important part of electric vehicles is the battery (secondary battery). Therefore, in this study, to analyze the stability of the CSM (Classifier Separator Mill) grinding disc that crushes secondary battery raw materials, structural analysis and vibration analysis of the 1st to 4th grinding discs and the final model were performed. The change of bending by the weight of the Grinding Disc is at least 0.065㎛ and maximum 0.075㎛, and the change by the standard gravity is judged to be very low. The strain is at least 0.00031㎛/㎛ and maximum 0.00078㎛/㎛, and even if the number of Hamer increases, the change by the weight is judged to be insignificant. When the Grinding Disc rotates at a maximum of 6000rpm, the deformation and deformation rate of the first to third models are similar, but the fourth model (Hamer 10EA) is more than three times and the final model (Hamer 12EA) is about four times. However, the maximum deformation is 28.21㎛, which is considered to be insignificant when the change is 6000rpm. Six modes of natural Frequency analysis of the 1st~4th order and final model of the grinding disc appeared to be bent or twisted.

• Journal of Preventive Medicine and Public Health
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• v.29 no.3 s.54
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• pp.565-577
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• 1996

This study was conducted to evaluate the association of work posture with cervical spine abnormality toward 106 microwave-oven assemblers. A self-administered questionnaire was used to obtain a general characteristics and a work history of workers. The posture of neck and shoulder joint of workers were measured with video tape recording and the simple X-ray of cervical spine was checked-up to observe the X-ray abnormality including degenerative change, curvature abnormality, disc space narrowing or disc canal narrowing. The result were as follows. 1. The prevalence of degenerative change among cervicobrachial disorder workers was 44.3% (47 persons), curvature abnormality was 43.4%(46 persons), disc space narrowing was 21.7%(23 persons), and disc canal narrowing was 21.7%(23 persons). 2. The prevalence of degenerative change at cervical spine was increased with the degree of neck flexion(flexed versus neutral, odds ratio [OR]=2.7), the total work posture of neck(mild or severe awkward versus neutral ; OR=1.2, 3.4). 3. The prevalence of degenerative change at cervical spine was increased with the degree of the right shoulder flexion, the heaviness of the materials carried by the right hand and the degree of awkwardness at the total work posture of right shoulder(p<0.05). 4. There was no evidence of association between curvature abnormality, disc space narrowing, disc canal narrowing and work posture. In conclusion the awkward work posture was related with degenerative change of cervical spine among microwave oven assembling workers and the further study in these field must be made to prove the association objectively.