• Journal of Yeungnam Medical Science
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• v.10 no.1
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• pp.114-126
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• 1993

The fractures of the cervical spine are relatively uncommon, but they may cause serious neurologic deficits temporarily or permanently. So, it is very important to treat the patients early by way of exact evaluation for the sites and the mechanisms of the injuries. The authors reviewed retrospectively 188 cervical spinal fractures in 100 patients from Sep. 1984 to Aug. 1990. Commonly involved levels were $C_5$ and $C_6$ in lower cervical level and $C_2$ in upper cervical level and the sites in each spine were body, lamina and odontoid process. The hyperflexion injury was the most common type of the cervical spinal fractures occupying 53% of all cervical fractures and cause more multiple fractures(2.26 fractures/patient) than in hyperextension(1.68 fractures/patient). In hyperflexion injuries, body, transverse and spinous process were commonly involved but lamina fracture was relatively common in hyperextension injury. The dislocations associated with fractures were developed most commonly in hyperflexion injury and 70% of these were anterior dislocation and the most commonly involved levels were $C_{5-6}$ and $C_{6-7}$. In conclusion, hyperflexion injury needs more close examination for the entire spinal levels than injuries of other mechanisms because it results in more severe fractures with or without dislocation and relatively frequent multiple fractures in different levels.

• Korean Journal of Materials Research
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• v.5 no.2
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• pp.169-177
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• 1995

The diffusion barrier property of 100-nm-thick titanium nitride (TiN) film between Cu and Si was investigated using sheet resistance measurements, etch-pit observation, x-ray diffractometry, Auger electron spectroscopy, and transmission electron microscopy. The TiN barrier fails due to the formation of crystalline defects (dislocations) and precipitates (presumably Cu-silicides) in the Si substrate which result from the predominant in-diffusion of Cu through the TiN layer. In contrast with the case of Al, it is identified that the TiN barrier fails only the in-diffusion of Cu because there is no indication of Si pits in the Si substrate. In addition, it appears that the stuffing of TiN does not improve the diffusion barrier property in the Cu/TiN/Si structure. This indicates that in the case of Al, the chemical effect that impedes the diffusion of Al by the reaction of Al with $TiO_{2}$ which is present in the grain boundaries of TIN is very improtant. On the while, in the case of Cu, there is no chemical effect because Cu oxides, such as $Cu_{2}O$ or CuO, is thermodynamically unstable in comparison with $TiO_{2}$. For this reason, it is considered that the effect of stuffing of TiN on the diffusion barrier property is not significant in the Cu/ TiN/Si structure.

• Journal of the Korean Vacuum Society
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• v.11 no.1
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• pp.50-58
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• 2002

The growth of GaN films on Si substrate has many advantages in that Si is less expensive than sapphire substrate and that integration of GaN-based devices with Si substrate is easier The difference of lattice constant and thermal expansion coefficient between GaN and Si is larger than those between GaN and sapphire. However, which results in many defects into the grown GaN. In order to obtain high duality GaN films on Si substrate, we need to reduce defects using the buffer layer such as AlN. In this study, we prepared three types of AlN buffer layer with various crystallinity on Si (111) substrate using MOCVD, Sputtering and MOMBE methods. GaN was grown by MOCVD on three types of AlN/Si substrate. Using TEM and XRD, we carried out comparative investigation of growth and properties of GaN deposited on the various AlN buffers by characterizing lattice coherency, crystallinity, growth orientation and defects formed (voids, stacking faults, dislocations, etc). It is found that the crystallinity of AlN buffer layer has strong effects on growth of GaN. The AlN buffer layers grown by MOCVD and MOMBE showed the reduction of out-of-plane misorientation of GaN at the initial growth stage.

• Clinics in Shoulder and Elbow
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• v.11 no.1
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• pp.46-52
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• 2008

Purpose: This study examined the outcomes of reconstruction of the coracoclavicular ligaments with using two suture anchors and performing coracoacromial ligament transfer in patients with acromioclavicular dislocation. Material and methods: Forty patients with complete acromioclavicular dislocation were included in this study. According to the preoperative radiographs, 5 patients with AC dislocations were diagnosed as type III, 4 patients as type IV and 31 patients as type V. Two 3.5mm suture anchors with four strands of nonabsorbable sutures were separately placed on the anterolateral and posteromedial portion of the base of the coracoid process to stabilize the distal clavicle. The coracoacromial ligament was then transferred to the undersurface of the distal end of the clavicle for augmentation. Results: At a mean follow-up of 28 months, the average Constant score improved to 97 points. All the patients returned to normal life at an average of 3.2 months postoperatively. At the last follow-up, 37 patients achieved anatomical reduction and three patients showed complete redislocation. However, the clinical results of the patients with redislocation were satisfactory. Conclusion: Anatomical coracoclavicular reconstruction using two suture anchors and coracoacromial ligament transfer for treating complete acromioclavicular dislocation is a safe, effective procedure for restoring a physiologically stable acromioclavicular joint.

• Journal of agricultural medicine and community health
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• v.33 no.1
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• pp.82-89
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• 2008

Objective:　We compared the prevalence of injury and poisoning in the agricultural and fishery population with that of the general population.Methods: The national health insurance data and agricultufor this study. The age-adjusted standardized morbidity ratio was used to compare the prevalence of all injuries and poisonings of the agricultural and fishery population with that of the general population for the year 2002, as well as the prevalence of certain injuries and poisonings common to the agricultural and fishery population. The age-adjusted standardized morbidity ratio and 95% confidence intervals were attained by using the general population as the standard population group.Results: The age-adjusted standardized morbidity ratio of total injuries and poisonings was significantly high in the agriculture and fishery population. The standardized morbidity ratio was 137.6 in the male agriculture and fishery population and 123.3 in the female agriculture and fishery population. In terms of injuries and poisonings common to the agriculture and fishery population, the age-adjusted standardized morbidity ratio was significantly high regarding the dislocations and strains of lumbar spine/pelvis, shoulder and neck, the fracture of rib/thoracic spine/sternum and pesticide poisoning.Conclusions: The overall prevalence of injury/poisoning was significantly higher in the agriculture and fishery population than in the general population. Various forms of research should be conducted on the injuries of the agriculture and fishery population in the future. In order to compare the differences in the prevalence rates of injuries according to time and region, standard definitions of injuries and occupation related injuries are required.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.327.1-327.1
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• 2014

Nitrides-on-silicon structures are considered to be an excellent candidate for unique design architectures and creating devices for high-power applications. Therefore, a lot of effort has been concentrating on growing high-quality III-nitrides on Si substrates, mostly Si(111) and Si(001) substrates. However, there are several fundamental problems in the growth of nitride compound semiconductors on silicon. First, the large difference in lattice constants and thermal expansion coefficients will lead to misfit dislocation and stress in the epitaxial films. Second, the growth of polar compounds on a non-polar substrate can lead to antiphase domains or other defective structures. Even though the lattice mismatches are reached to 16.9 % to GaN and 19 % to AlN and a number of dislocations are originated, Si(111) has been selected as the substrate for the epitaxial growth of nitrides because it is always favored due to its three-fold symmetry at the surface, which gives a good rotational matching for the six-fold symmetry of the wurtzite structure of nitrides. Also, Si(001) has been used for the growth of nitrides due to a possible integration of nitride devices with silicon technology despite a four-fold symmetry and a surface reconstruction. Moreover, Si(110), one of surface orientations used in the silicon technology, begins to attract attention as a substrate for the epitaxial growth of nitrides due to an interesting interface structure. In this system, the close lattice match along the [-1100]AlN/[001]Si direction promotes the faster growth along a particular crystal orientation. However, there are insufficient until now on the studies for the growth of nitride compound semiconductors on Si(110) substrate from a microstructural point of view. In this work, the microstructural properties of nitride thin layers grown on Si(110) have been characterized using various TEM techniques. The main purpose of this study was to understand the atomic structure and the strain behavior of III-nitrides grown on Si(110) substrate by molecular beam epitaxy (MBE). Insight gained at the microscopic level regarding how thin layer grows at the interface is essential for the growth of high quality thin films for various applications.

• Korean Journal of Materials Research
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• v.30 no.10
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• pp.542-549
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• 2020

Effects of Sc addition on microstructure, electrical conductivity, thermal conductivity and mechanical properties of the as-cast and as-extruded Al-2Zn-1Cu-0.3Mg-xSc (x = 0, 0.25, 0.5 wt%) alloys are investigated. The average grain size of the as-cast Al-2Zn-1Cu-0.3Mg alloy is 2,334 ㎛; however, this value drops to 914 and 529 ㎛ with addition of Sc element at 0.25 wt% and 0.5 wt%, respectively. This grain refinement is due to primary Al₃Sc phase forming during solidification. The as-extruded Al-2Zn-1Cu-0.3Mg alloy has a recrystallization structure consisting of almost equiaxed grains. However, the as-extruded Sc-containing alloys consist of grains that are extremely elongated in the extrusion direction. In addition, it is found that the proportion of low-angle grain boundaries below 15 degree is dominant. This is because the addition of Sc results in the formation of coherent and nano-scale Al₃Sc phases during hot extrusion, inhibiting the process of recrystallization and improving the strength by pinning of dislocations and the formation of subgrain boundaries. The maximum values of the yield and tensile strength are 126 MPa and 215 MPa for the as-extruded Al-2Zn-1Cu-0.3Mg-0.25Sc alloy, respectively. The increase in strength is probably due to the existence of nano-scale Al₃Sc precipitates and dense Al₂Cu phases. Thermal conductivity of the as-cast Al-2Zn-1Cu-0.3Mg-xSc alloy is reduced to 204, 187 and 183 W/MK by additions of elemental Sc of 0, 0.25 and 0.5 wt%, respectively. On the other hand, the thermal conductivity of the as-extruded Al-2Zn-1Cu-0.3Mg-xSc alloy is about 200 W/Mk regardless of the content of Sc. This is because of the formation of coherent Al₃Sc phase, which decreases Sc content and causes extremely high electrical resistivity.

• Journal of Korean Orthopaedic Sports Medicine
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• v.2 no.2
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• pp.77-81
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• 2003

Purpose: The biomechanics and kinematics of knee joint were reviewed in this article. And then the common sports injuries were presented. Anatomy and Kinetics: None of the pairs of bearing surfaces in the knee joint is exactly congruent This allows the knee six degrees of freedom of motion. Tibiofemoral Kinematics: In flexion and extension, the axis of motion is not perpendicular to the medial-lateral plane of the joint, nor is it perpendicular to the axis of longitudinal rotation. This results in coupled varus angulation and internal rotation with flexion and in valgus angulation and external rotation with extension. Patellofemoral Articulation: Loads across the patellofemoral joint are indirectly related to the angle of knee flexion and directly related to the force generated within the quadriceps mechanism. Fractures of the Patella: Nonoperative treatment is indicated if the extensor mechanism is intact and if displacement of fragment is minimal. The specific type of internal fixation depends on the fracture pattern. It is important to repair retinaculum. Acute and Recurrent Patellar Instability: The degree of dysplasia and the extent of the instability play a large part in determining the success of nonoperative treatment. Patients who experience recurrent dislocations and patients with major anatomic variations require surgery to minimize their instability. Sports Injuries in School-age Atheletes: Patellar pain in young athletes groups a number of conditions, including Idiopathic Adolescent Anterior Knee Pain, Osgood- Schlatter Disease, and Sinding-Larsen-Johansson Disease.

• Clinics in Shoulder and Elbow
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• v.1 no.2
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• pp.205-211
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• 1998

The comminuted fracture and dislocation of the proximal humerus occur more frequently in older patient group and operative treatment is difficult due to poor bone quality. Based on Neer's work, hemiarthroplasty has now become widly accepted for the management of the three-part fracture and four-part fracture-dislocation of the proximal humerus in old age group. The purpose of this study is to evaluate function, pain relief, and patient satisfaction after hemiarthroplasty for proximal humerus fractures and dislocations. Authors reviewed and analyzed 14 prosthetic replacement in comminuted proximal humeral fracture and dislocation at the Department of Orthopaedic Surgery, Yonsei University Wonju College of Medicine from March, 1988 to May, 1997. The results were as follows the average age was 58.9years and the ratio of males and females was 5:9. The most common cause of injury was traffic accident(43%). According to the classification of Neer, three part fracture were three(21%), four-part fracture and four-part fracture-dislocation were eleven(79%). The prosthetic replacement was performed within two weeks in eight patient and six were performed after two weeks. The results were analysed according to Neer's criteria and five cases showed satisfactory results. We concluded that hemiarthroplasty for fracture and dislocation of the proximal humerus facilitated the restoration of humerus length and pain relief, thereby allowing earlier motion to prevent the development of painful shoulder: stiffness.

• Clinics in Shoulder and Elbow
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• v.13 no.2
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• pp.194-201
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• 2010

Purpose: We evaluated clinical and radiological results for open reduction and internal fixation of acromioclavicular dislocation without coracoclavicular ligament repair after removal of implants. Materials and methods: Clinical and radiological results were obtained for 53 patients who underwent open reduction and internal fixation of an acromioclavicular joint dislocation between 1998 and 2007. A total of 21 patients were treated with a modified-Phemister method and 32 patients were treated with a Hook plate method. All subjects were surveyed after removal of their implants. The Constant scoring system was administered postoperatively to evaluate clinical results. Radiologic outcomes were evaluated by both coracoclavicular intervals on plain films. Results: Constant scores were $87.59{\pm}7.8$ in the Phemister group and $89.35{\pm}5.3$ in the Hook plate group. For both groups, the mean coracoclavicular interval at preoperative radiography was 15.9 mm at the injured site and 8.0 mm at the opposite site. After metal removal, the mean difference between coracoclavicular distances between normal and injured sites were 1.0 mm for the Hook plate group and 1.2 mm for the modified Phemister method group (p>0.05). Conclusion: Open reduction and internal fixation of an acromioclavicular joint without coracoclavicular ligament repair shows good long-term clinical and radiological results.