• 한국터널지하공간학회 논문집
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• 제16권2호
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• pp.181-191
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• 2014

본 연구는 선형절삭시험 중에 동일한 커터 링 형상을 가진 더블디스크커터와 싱글디스크커터에 발생하는 커터작용력과 각 디스크커터 축에 발생하는 축응력 및 토크를 평가하였다. 선형절삭시험 결과, 선형절삭실험 중에 발생한 더블디스크커터의 연직력과 회전력의 평균값은 싱글디스크커터의 약 두 배 내외인 것으로 측정되었다. 더블디스크커터의 축에 작용하는 축응력의 평균값 역시 연직력과 마찬가지로 싱글디스크커터의 두 배 정도로 나타났지만, 토크의 경우에는 전체적으로 낮은 측정값을 보여 비교의 의미가 없는 것으로 판단되었다. 하지만 더블디스크커터의 연직력의 평균값이 직경 432 mm(17인치) 디스크커터의 허용하중을 상회하기 때문에 테이퍼 롤러 베어링의 내구성능에 대한 검토가 필요한 것으로 판단되었다. 또한 더블디스크커터 축에 작용하는 축응력은 싱글디스크커터의 약 두 배 정도로 발생하였지만, 일반적으로 사용하는 디스크커터 축 재료의 항복강도를 고려할 때 적용 상에 문제가 없는 것으로 나타났다.

• Imaging Science in Dentistry
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• 제31권4호
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• pp.235-240
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• 2001

Purpose: To evaluate displacement and morphologic changes of the temporomandibular joint (TMJ) disc in patient with internal derangement using magnetic resonance imaging (MRI). Materials and Methods: One hundred and forty five MR images of TMJs in 73 patients were evaluated. Positional and morphologic changes of the TMJ discs were assessed. Lateral or medial disc displacement was also evaluated on coronal images. Results: Among 63 discs with anterior disc displacement, 37 discs were assessed as a biconcave disc and 21 as a deformed disc. Rotational disc displacement was observed in 35 discs. Anteromedial disc displacement was observed in 29 discs, and anterolateral direction in 6 discs. Among 35 rotational displacement, 5 biconcave discs and 21 deformed discs were observed. Conclusion : Rotational and sideways displacement of TMJ discs were found to be common and an important aspect of internal derangement. This study also suggests that sagittal and coronal images of the TMJ have complementary abilities for an assessment of joint abnormality.

• 대한기계학회논문집A
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• 제26권2호
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• pp.234-242
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• 2002

A shape optimal design of synthetic intervertebral disc prosthesis is performed using a three-dimensional finite element method. Geometric parameters are introduced to model the cross-sectional geometry of the intervertebral disc. It is assumed that the total strain energy in the intact intervertebral disc is minimized under the normal load conditions, as often cited in other references. To calculate the stain energy density, both the nonlinear material properties and the large deformations are taken into account. The design variables of the annulus fiber angle and the area ratio of the nucleus pulposus are calculated as 31°and 30%, respectively, which complies well with the intact disc. Thus, the same optimization procedure is applied to the design of the synthetic intervertebral disc prosthesis whose material properties are different from the intact disc. For the given synthetic material properties, the values of 67°and 24% for the fiber angle and the area ratio are obtained.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.1300-1303
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• 2004

Copper는 낮은 저항률과 높은 Electromigration 저항 때문에 반도체 소자에 배선 재료로 사용된다. CMP 공정을 이용 하여 Cu wafer의 여러 가지 특성을 파악하기에는 wafer의 소모량이 많고 고가가의 비용이 예상 되므로, 본 논문에서는 비용절감을 위하여 wafer를 Disc로 대체 하고자 실험을 진행 하였고 Cu wafer와 Disc의 비료 방법은 우선 PM-5 (Genitech. co) 장비를 이용하여 removal rate의 차이점을 알 아 보았으며, 서로의 etch rate을 reomval rate과 비교하였다. EG&G 273A를 통하여 Cu wafer와 disc의 corrosion potential과 $R_p$ (Polarization resistance)값을 서로 비교 하였다. 이 논문에서는 이러한 것들을 서로 비교 하여, Cu wafer와 disc에서의 상관관계를 알고자 하였으며, 만약에 Cu wafer와 disc의 특성이 비슷하다면, Cu wafer 대신에 disc를 이용 하여 실험하여도 되는지에 관하여 조사 하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.396-401
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• 2008

The disc-pad brake system is an important part of automobile safety system. During braking, the kinetic energy and potential energies of a moving vehicle are converted into the thermal energy through frictional heat between the brake disc and the pads. Most of the thermal energy dissipated through the brake disc. The temperature could be exceed the critical value for a given material, which leads to undesirable effects, such as the brake fade, premature wear, brake fluid vaporization, bearing failure, thermal cracks, and thermallyexcited vibration. The object of the present study is to investigate temperature field and temperature variation of brake disc and pad during single brake. The brake disc is decelerated at the initial speed with constant acceleration, until the disc comes to stop. The pad-disc brake assembly is built by 3D model with the appropriate boundary condition. In the simulation process, the mechanical loads are applied to the thermomechanical coupling analysis in order to simulate the process of heat produced by friction.

• 척추신경추나의학회지
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• 제6권1호
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• pp.53-61
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• 2011

Objective: The purpose of this study is to evaluate the disc block subluxation for lumbar scoliosis and herniation of nucleus pulpous (HNP). Methods: We used AP & Lateral view X-ray for patients. And we measured of disc wedge angle, vertebral body rotation to evaluate the typical and atypical disc block subluxation. Results: On the analysis of the lateral view X-ray, 4th lumbar intervertebral disc angle (I.V.D angle) showed $4^{\circ}$, $5^{\circ}$, $3^{\circ}$, $0^{\circ}$ in the cases. On the 4th lumbar analysis of the AP view X-ray, lumbar scoliosis showed right disc wedge angle was $11^{\circ}$ (case 1), $17^{\circ}$ (case 2) and left vertebral body rotation was 13mm, 6mm. Lumbar HNP showed left disc wedge angle was $5^{\circ}$ (case 3), $4^{\circ}$ (case 4) and left vertebral body rotation was 2mm, 4mm. Conclusions: Disc block subluxation has been in lumbar scoliosis, but not been in lumbar HNP.

• 척추신경추나의학회지
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• 제5권1호
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• pp.101-110
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• 2010

Objectives: The propose of this study is to find out the clinical application of conservative treatment to 3 patients who has Disc Extrusion on L-spine MRI Methods: We examined 3 patients with Lumbar Intervertebral Disc Herniation (HIVD of L-spine) with Disc Extrusion who showed changes on MRI images before/after the treatment among HIVD of L-spine patients who visited Jaseng Hospital of Oriental Medicine. Results: In this study, the first MRI examination of HIVD of L-spine patients was performed at the first visit and re-examination of MRI was done after the treatment. In each case, the size of the extruded disc was considerably reduced in MRI image. Low back and leg pain was also reduced significantly after conervative oriental medical treatment. Conclusions: Conservative oriental medical treatment can be effective for improving symptoms of HIVD, decreasing pain, also decreasing the volume of herniated disc.

• Tribology and Lubricants
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• 제32권6호
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• pp.195-200
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• 2016

This study examines the wear behavior of mild steel pins mated against alloyed tool steel discs in a pin-on-disc type sliding test machine and provides specific clarification regarding the effects of disc hardness on the wear behavior of a mating mild steel pin. The analysis confirms these effects through the observation of differences in the wear rates of the mild steel pins at low sliding speed ranges. These differences occur even though the hardness of the mating disc does not affect the wear characteristic curve patterns for the sliding speeds, regardless of the wear regime. In the running-in wear regime, increasing the hardness of the mating disc results in a decrease in the wear rates of the mild steel pins at low sliding speed ranges. However, in the steady-state wear region, the wear rate of a pin mated against the 42DISC is greater than the wear rate of a pin mated against the 30DISC, which has a lower hardness value. This means that the tribochemical reactivity of the mating disc, which is based on hardness value, influences the wear behavior of mild steel at low sliding speed ranges. In particular, oxides with higher oxygen contents, such as $Fe_2O_3$ oxides, form predominantly on the worn surface of the 42DISC. On the contrary, the wear behavior of mild steel pins at high sliding speed ranges is nearly unaffected by the hardness of the mating disc.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.248-251
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• 2005

To investigate the degeneration process in the intervertebral disc, a three dimensional (3D) poroelastic finite-element (FE) model was developed. Disc was modeled as two different regions, such as annulus modeled with fiber reinforced 20 node poroelastic ground matrix and nucleus having large porosity. Excess Von Mises stress in the disc element assumed to be a possible source of degeneration under compressive loading condition. Recursive calculation was continued until the desired convergence was attained by changing the permeability and porosity of those elements, which could be predicted from the previous iteration. The degenerated disc model showed that relatively small compressive stresses were generated in the nucleus elements compared to normal disc. Its distribution along the sagittal plane was matched well with a previously reported experimental result. Contrasts to this result, pore pressures in the nucleus were higher than those in the normal disc. Total stress indicated similar values for two different models. This new approach using poroelastic modeling could provide the explanation of the interaction between fluid and solid matrix in the disc during the degeneration process.

• Journal of Korean Neurosurgical Society
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• 제53권6호
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• pp.323-330
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• 2013

Objective : To develop a simple, reproducible model of disc degeneration in rabbits through percutaneous annular puncture and to confirm the degree of degeneration over time. Methods : Fifteen New Zealand white rabbits (4 to 5 months old and weighing approximately 3 to 3.5 kg each) underwent annular puncture of the L2-L3, L3-L4, and L4-L5 discs. Rabbits were sacrificed at 4, 8, or 20 weeks after puncture. For a longitudinal study to assess changes in disc height over time, serial X-rays were performed at 0, 2, 4, 8, and 20 weeks for rabbits in the 20-week group. Upon sacrifice, the whole spinal column and discs were extracted and analyzed with magnetic resonance imaging (MRI), real time reverse transcriptase-polymerase chain reaction, and histological staining. Results : The X-rays showed a slow, progressive decrease in disc height over time. Significant disc space narrowing compared to preoperative disc height was observed during the time period (p<0.001). The MRI grade, aggrecan, and matrix metalloprotease-13 mRNA expression and hematoxylin and eosin/safranin O/anti-collagen II staining were consistently indicative of degeneration, supporting the results of the X-ray data. Conclusion : Percutaneous annular puncture resulted in slow, reproducible disc degeneration that was confirmed by radiology, biochemistry, and histology. This in vivo model can be used to study and evaluate the safety and efficacy of biologic treatments for degenerative disc disease.