• Investigative Magnetic Resonance Imaging
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• 제22권1호
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• pp.18-25
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• 2018

Purpose: To investigate the various imaging factors associated with aggravation of lumbar disc herniation (LDH) and develop a scoring system for prediction of LDH aggravation. Materials and Methods: From 2015 to 2017, we retrospectively reviewed the magnetic resonance imaging (MRI) findings of 60 patients (30 patients with aggravated LDH and 30 patients without any altered LDH). Imaging factors for MRI evaluation included the level of LDH, disc degeneration, back muscle atrophy, facet joint degeneration, ligamentum flavum thickness and interspinous ligament degeneration. Flexion-extension difference was measured with simple radiography. The scoring system was analyzed using receiver operating characteristic (ROC) analysis. Results: The aggravated group manifested a higher grade of disc degeneration, back muscle atrophy and facet degeneration than the control group. The ligamentum flavum thickness in the aggravated group was thicker than in the group with unaltered LDH. The summation score was defined as the sum of the grade of disc degeneration, back muscle atrophy and facet joint degeneration. The area under the ROC curve showing the threshold value of the summation score for prediction of aggravation of LDH was 0.832 and the threshold value corresponded to 6.5. Conclusion: Disc degeneration, facet degeneration, back muscle atrophy and ligamentum flavum thickness are important factors in predicting aggravation of LDH and may facilitate the determination of treatment strategy in patients with LDH. The summation score is available as supplemental data.

• Journal of Oral Medicine and Pain
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• 제25권1호
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• pp.63-71
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• 2000

The authors assessed if there is a relationship between joint effusion and the presence of pain, and between joint effusion and disc displacement in 446 temporomandibular joints of 223 subjects who visited the Department of Oral Medicine, Kyungpook National University Hospital with the complaints of temporomandibular joint problem. The amount of joint effusion and the position of disc were determined from magnetic resonance images of the temporomandibular joints. The position of disc was classified into normal disc position, disc displacement with reduction (DDWR), and disc displacement without reduction (DDWOR). The amount of joint effusion was graded according to the extent of joint area of high signal intensity on T2-weighted MR images. These findings were correlated with one another and statistically analyzed. The results were as follows; 1. The incidence of temporomandibular joint pain Was higher in the joints with higher amount of joint effusion (P<0.001). 2. The proportion of temporomandibular joints with higher amount of effusion increased in the joints with more advanced articular disc displacement (P<0.001).

• 한국생산제조학회지
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• 제23권3호
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• pp.259-265
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• 2014

When the brakes of a vehicle are applied, large amounts of heat are generated on the surfaces of the brake discs owing to friction between the discs and the brake pads. A high temperature gradient on the disc surfaces leads to thermal deformation and severe disc abrasion. Ultimately, the thermal deformation and disc wear give rise to a thermal judder phenomenon, which has a major effect on the stability of the vehicle. To investigate and propose a solution to these problems, thermoelastic instabilities under applied thermal and mechanical loads were analyzed using the commercial finite element package ANSYS by considering the contact surfaces between the discs and pads. Direct-contact three-dimensional finite elements between the discs and pads were applied to investigate the disc friction temperature, thermal deformation, and contact stress so that the thermal judder phenomenon on the surface of the disc could be predicted.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제27권4호
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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.

• 한국화재소방학회논문지
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• 제16권2호
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• pp.33-37
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• 2002

본 연구에서는 소화용수 제어에 사용되고 있는 버터플라이 밸브의 디스크에 대한 유체역학 토크특성을 연구하였다. 자유-유선 이론이 유체역학 토크특성을 예측하는데 응용되었다. 디스크의 토크특성은 토크 이론식에 밸브 디스크의 개도각과 주변속도가 보정되었고, 보정식이 추가되었다. 디스크의 토크특성은 허브의 두께와 직경 비에 대해 조사하였다. 예측결과는 버터플라이 밸브의 전형적인 특성을 보여줌으로서 성공적인 것으로 보여진다. 디스크 주변의 속도분포를 가시적으로 확인함으로서, 자유-유선이론이 디스크의 토크특성를 예측하는데 사용될 수 있음을 확인하였다.

• 한국한의학연구원논문집
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• 제16권2호
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• pp.119-124
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• 2010

Cervical disc herniations can press on the spinal cord and cause a problem called cervical myelopathy. The most common symptom of cervical disc herniation is neck pain that spreads down to the upper limb in various locations. There can also be associated with weakness and movement disorders of upper limb. In Oriental medicine, cervical disc herniation is treated with herb-med, physical therapy, acupuncture, Chuna, etc, but the Bee Venom therapy is the most common and effective. In this case, we used the Bee Venom therapy at cervical hyeopcheokhyeol for about 2 months to a patient who was diagnosed with disc herniation at Cervical 5-6, 6-7 and appealed weakness, limited elevation and abduction of the left upper limb. As a result, left upper limb disability was improved. Using the Bee Venom therapy at cervical hyeopcheokhyeol that are effective on movement disorders and neurological diseases of upper limb is an effective treatment to upper limb disability diagnosed with cervical disc herniation, and suggests the direction of the treatment to upper limb weakness and movement disorders diagnosed with cervical disc herniation.

• 한국기계가공학회지
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• 제12권3호
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• pp.13-20
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• 2013

The present research aims to develop the aluminum disc brake replacing the existing cast iron disc brake. Material such as aluminum using FEM numerical analysis in order to improve the characteristics of each element, we analyze the performance characteristics and braking time you try to change. We try to lay the foundation for the development of an aluminum disc by investigating performance characteristics of the existing cast iron disc brake and comparing them with those of the aluminum disc. This involves FEM dynamics analysis for disc materials and experimental tests using the brake dynamometer. From this study, the results of 7075 aluminum braking performance can be seen that the best.

• 한국자동차공학회논문집
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• 제16권1호
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• pp.100-105
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• 2008

Cross-drilling on the brake disc is generally known as a way of improving cooling efficiency. In other theories, cross-drilled holes act like a path of gas or water and are also known that they can reduce fading and wetting of brake rotors. However, in disc rotors with cross-drilling, thermal crack phenomena have been reported more frequently and more manufacturing cost should be paid than non cross-drilled disc rotors. In this study, to examine various effects of cross-drilling on the brake disc, two kinds of brake disc rotors, cross-drilled and non cross-drilled, were used in computational fluid dynamic analyses and dynamometer tests.

• Journal of Korean Neurosurgical Society
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• 제55권6호
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• pp.383-386
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• 2014

Objective : Symptomatic thoracic disc herniation often requires prompt surgical treatment to prevent neurological deterioration and permanent deficits. Anterior approaches offer direct visualization and access to the herniated disc and anterior dura but require access surgeons and are often associated with considerable postoperative pain and pulmonary complications. A disadvantage with using posterior approaches in the setting of central calcified thoracic disc herniation however, has been the limited visualization of anterior dura and difficulty to accurately assess the extent of decompression. Methods : We report our experience with intraoperative ultrasound (US) guidance during a modified posterior transpedicular approach for removal of a central calcified thoracic disc herniation with a review of pertinent literature. Results : The herniated thoracic disc was successfully removed with posterior approach with the aid of intraoperative US. The patient had significant neurological improvement at three months follow-up. Conclusion : Intraoperative ultrasound is a simple yet valuable tool for real-time imaging during transpedicular thoracic discectomy. Visualization provided by intraoperative US increases the safety profile of posterior approaches and may make thoracotomy unnecessary in a selected group of patients, especially when a patient has existing pulmonary disease or is otherwise not medically fit for the transthoracic approach.

• Tribology and Lubricants
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• 제25권6호
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• pp.421-426
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• 2009

The brake system is important part of automobile safety system. The disc brake system is divided two parts: the rotating axisymmetrical disc and the stationary pads. During braking, the kinetic energy and potential energy of moving vehicle were converted into the thermal energy through frictional heat between the brake disc and the pads. The frictional heat, which is generated on the interface of the disc and pads, can cause high temperature during the braking process. The object of present work is to determine temperature and thermal stress, to compare to simulation results and experimental results in the disc by partial 3D model of ventilated disc brake with appropriate boundary conditions. In the simulation process, the mechanical loads were applied to the thermo-mechanical coupling analysis in order to simulate the process of heat produced by friction.