• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.5
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• pp.249-257
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• 1999

A three dimensional finite model of a human neck has been developed in an effort to study the mechanics of cervical spin while subjected to vertical impact. This model consisting of the vertebrae from C1 through C7 including posterior element and ligaments was constructed by 2mm thick transverse CT cross-sections and X-ray film taken at lateral side. Geometrical nonlinearity was also considered for the large deformation on the disc. ABAQUS package was used for calculation and its results were verified comparing with responses of a model under static loading condition with published in-vitro experimental data. There were more cervical fracture in the restrained (compression) mode than in the nonrestrained (flexion-compression and extension-compression) mode. Upper cervical(C1-C2) injuries were observed under compression-extension modes, while lower cervical injuries occurred undjer compression-flexion modes. Posterior ligament distraction without bony damage at the upper cervical spin(C1-C2) were observed secondary to C5-C7 trauma in compression-flexion modes.

• Journal of Korean Foot and Ankle Society
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• v.1 no.2
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• pp.119-125
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• 1997

The fracture and fracture-dislocation of the neck of the talus (Hawkins' type I-IV) are uncommon injuries and represent only 0.12 to 0.32% of all fracures. Authors clinically evaluated in 12 cases Whom treated fracures of the neck of the talus, at department of orthopaedic surgery, Sun General Hospital, from 1990 to 1996, and the following results are obtained. 1. Of 12 cases, there were 11 males and 1 female, average age was 30 years. 2. Causes of fracture was fall down injury in 7 cases(58%), traffic accident in 4 cases(33%), direct trauma in 1 case(8%). 3. According to the classification by Hawkins' type I in 2 cases(17%), type II in 7cases (58%), type III in 3cases(25%). 4. Associated injuries were calcaneal fracture in 3 cases, fracture-dislocation of talus in 3 cases, subtalar dislocation in 3 cases, medial malleolar fracture in 5 cases, soft tissue injury in 3 cases, femur and tibia fracture in 1 case, and lumbar Spine compression fracture in 1 case. 5. Average time to operation after injury was 2.5 days. 6. In 2 cases were treated conservatively and 10 cases were treated open reduction and internal fixation with screw or K-wire. 7. Complications were avascular necrosis in 4 cases, post traumatic arthritis in 2 cases, skin necrosis in 4 cases, and then ankle fusion was done in 2 cases. 8. High rate of complication was seen in the talar neck fracture associated with calcaneal fracture. In the analysis of above results, evaluated by Hawkins' scoring system were excellent to fair in 75%.

• Clinics in Shoulder and Elbow
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• v.11 no.2
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• pp.137-142
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• 2008

Purpose: To evaluate the clinical and radiographic results of the treatment of a proximal humerus fracture with a locking compression plate(LCP). Materials and Methods: This study reviewed the results of 24 cases of a proximal humerus fracture treated with a LCP from January 2005 to April 2007, after a follow up of more than 12 months. There were 8 males and 16 females with a mean age of 68.9(33-90) years. The clinical results were evaluated using the Neer's evaluation criteria, and the radiographic results were evaluated using the bone union time and Paavoleinen method. Results: The mean time for bone union was 11.9 weeks. Using the Neer's functional evaluation, 21 cases of the 24 patients (87%) showed excellent or satisfactory results. Twenty two cases (91%) showed good results according to the Paavoleinen method. The complications encountered were metal failure (1 patient), AVN of the humeral head (1 patient) and joint stiffness (1 patient). Conclusion: The LCP demonstrated good results in the treatment of a proximal humerus fracture and has relatively fewer complications than other internal fixators.

• Journal of Korean Neurosurgical Society
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• v.64 no.3
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• pp.437-446
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• 2021

Objective : To investigate the radiographic characteristics of the uppermost instrumented vertebrae (UIV) and UIV+1 compression fractures that are predictive of revision surgery following long-segment spinal fixation. Methods : A total 27 patients who presented newly developed compression fracture at UIV, UIV+1 after long segment spinal fixation (minimum 5 vertebral bodies, lowest instrumented vertebra of L5 or distal) were reviewed retrospectively. Patients were divided into two groups according to following management : revisional surgery (group A, n=13) and conservative care (group B, n=14). Pre- and postoperative images, and images taken shortly before and after the occurrence of fracture were evaluated for radiologic characteristics Results : Despite similar degrees of surgical correction of deformity, the fate of the two groups with proximal junctional compression fractures differed. Immediately after the fracture, the decrement of adjacent disc height in group A (32.3±7.6 mm to 23.7±8.4 mm, Δ=8.5±6.9 mm) was greater than group B (31.0±13.9 mm to 30.1±15.5 mm, Δ=0.9±2.9 mm, p=0.003). Pre-operative magnetic resonance imaging indicated that group A patients have a higher grade of disc degeneration adjacent to fractured vertebrae compared to group B (modified Pfirrmann grade, group A : 6.10±0.99, group B : 4.08±0.90, p=0.004). Binary logistic regression analysis indicated that decrement of disc height was the only associated risk factor for future revision surgery (odds ratio, 1.891; 95% confidence interval, 1.121-3.190; p=0.017). Conclusion : Proximal junctional vertebral compression fractures with greater early-stage decrement of adjacent disc height were associated with increased risk of future neurological deterioration and necessity of revision. The condition of adjacent disc degeneration should be considered regarding severity and revision rate of proximal junctional kyphosis/proximal junction failures.

• Journal of the Korean Orthopaedic Association
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• v.56 no.1
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• pp.76-81
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• 2021

A traumatic dislocation of the sternoclavicular joint is a rare injury, and among them, anterior dislocation is more common than a posterior dislocation. Posterior dislocation is a potential risk by compressing the mediastinal structures, but an anterior dislocation has not been considered a risk. Traumatic sternoclavicular joint anterior dislocation associated with anterior angulation of a sternal fracture can develop mediastinal compression and have a risk in the same way as a posterior dislocation. This case report is about a traumatic sternoclavicular joint anterior dislocation with a sternal fracture accompanied by mediastinal compression that was treated surgically using a plate and showed relatively good clinical results. This rare case is reported along with a review of the relevant literature.

• Geomechanics and Engineering
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• v.32 no.3
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• pp.245-254
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• 2023

Through qualitative analysis and quantitative analysis, the contradictory conclusions about the stability of the settled goaf with two-layer coal seams subject to building load were obtained. Therefore, it is necessary to combine the additional stress method and numerical simulation to further analyze the foundation stability. Through borehole analysis and empirical formula analogy, the height of water-conducting fracture zone in No.4 coal and No.9 coal were obtained, providing the calculation range of water-conducting fracture zone for numerical simulation. To ensure the accuracy of the elastic modulus of broken gangue, the stress-strain curve were obtained by broken gangue compression test in dried state of No.4 coal seam and in soaking state of No.9 coal seam. To ensure the rationality of the numerical simulation results, the actual measured subsidence data were retrieved by numerical simulation. FISH language was used to analyze the maximum building load on the surface and determine the influence depth of building load on the foundation. The critical building load was 0.16 MPa of No.4 settled goaf and was 1.6 MPa of No.9 settled goaf. The additional stress affected the water-conducting fracture zone obviously, resulted in the subsidence of water-conducting fracture zone was greater than that of bending subsidence zone. In this paper, the additional stress method was analyzed by numerical simulation method, which can provide a new analysis method for the treatment and utilization of the settled goaf.

• Tunnel and Underground Space
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• v.33 no.2
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• pp.83-94
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• 2023

Unlike the conventional triaxial test cells for cylindrical specimens, which impose uniform lateral confining pressures, the GREAT (Geo-Reservoir Experimental Analogue Technology) cell can exert differential radial stresses using eight independently-controlled pairs of lateral loading elements and thereby generate horizontal stress fields with various magnitudes and orientations. In the preceding companion paper, GREAT cell tests were numerically simulated under different mechanical loading conditions and the validity of the numerical model was investigated by comparing experimental and numerical results for circumferential strain. In the present study, we simulated GREAT cell tests for an artificial sample containing a fracture under both mechanical loading and fluid flow conditions. The numerical simulation was carried out by varying the mechanical properties of the fracture surface, which were unknown. The numerical responses (circumferential strains) of the sample were compared with experimental data and a good match was found between the numerical and experimental results under certain mechanical conditions of the fracture surface. Additionally, the effect of fluid flow conditions on the mechanical behavior of the sample was investigated and discussed.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.3
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• pp.11-15
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• 2010

In this paper, we focused on the optimization of bonding conditions for the successful thermo-compression bonding of electrodes between the RPCB and FPCB with Sn-Pb solder. The peel strength was proportionally affected by the bonding conditions, such as pressure, temperature, and time. In order to figure out an optimized bonding condition, fracture energies were calculated through F-x (force-displacement) curves in the peel test. The optimum condition for the thermo-compression bonding of electrodes between the RPCB and FPCB was found to be temperature of $225^{\circ}C$ and time of 7 s, and its peel strength was 22 N/cm.

• The Journal of Internal Korean Medicine
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• v.42 no.5
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• pp.1027-1034
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• 2021

Objectives: This study aimed to determine the effects of Korean medical treatment on a patient with compression fractures. Methods: The patient was treated with herbal medicine and acupuncture for 51 days. Symptom changes were measured using the Numerical Rating Scale (NRS), Range of Motion (ROM), Oswestry Disability Index (ODI), and European Quality of Life Five Dimensions (EQ-5D) Scale. Results: The NRS score for lower back pain decreased from 7 to 3, and the ODI score decreased from 51.11 to 22.22. Range of motion (ROM) increased meaningfully in flexion(from 30 to 60), Left/Right lateral bending(from 10/30 to 30/45), Left/Right rotation (from 10/30 to 30/45), and the EQ-5D score also increased from 0.506 to 0.677. Conclusion: The results indicate that Korean medical treatment may be effective for managing patients' acute compression fractures.

• Tunnel and Underground Space
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• v.12 no.4
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• pp.304-311
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• 2002

This study reports the influence of vocid geometry on fracture closure and permeability from numerical experiments. As the aperture distributions of rock fractures are characterized by statistical methods, synthetic fractures have successfully been simulated in this way. Based on the generated fracture models, models for fracture closure and flow calculation have been developed. A fracture closure model has been developed by considering the asperity compression and half-space deformation, and flow calculations have been performed using a finite difference method adopting a local cubic law. The results of numerical experiments have shown that the increase in the aperture spatial correlation leads the fracture closure and the decrease in fracture permeability to increase. Also, it has been indicated that there is an implicit relation between fracture normal stiffness and permeability. The importance of this study is to enhance the understanding the hydro-mechanical behavior of fractured rock massed due to engineering projects.