• Journal of the Korean Magnetics Society
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• v.6 no.1
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• pp.7-14
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• 1996

According to demands of high density and wide band magnetic recording systems, a composite MIG head was developed. This head has the sufficient performance for use of a SD VCR : its characteristics are a good recoding performance, a low rubbing noise, a good frequency dependence of efficiency, and a good compatibility with ME tape. In a SD VCR system, the C/N value of a composite MIG head at 20.92MHz was 51 dB.

• Korean Journal of Head & Neck Oncology
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• v.1 no.1
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• pp.63-74
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• 1985

Although regional and myocutaneous flaps are still the standard in head and neck reconstruction. The capacity to transfer distant tissues by microsurgical technique expands the reconstructive surgeon's ability to restore severe deformities of the head and neck. From 1981 to 1985, thirteen patients with extensive defects of the head and neck after extirpative surgery of tumor have been reconstructed utilizing the technique of microsurgical composite tissue transplantation. In this series of patients, six presented with reconstructions in the different region of the head and neck with review of literatures. The results of case analysis are summarized as follows: 1) Transplantation was successful in twelve among thirteen patients (92%). 2) Seven patients presented with malignancy and six with benign tumor. 3) Frequent sites of reconstruction were face and mandible. 4) Fourteen free composite tissue transplantations for reconstruction of thirteen patients were obtained six different tissue compositions from eight different donor sites. 5) The recipient artery and vein was most often superficial temporal or facial vessels. 6) The average time of operation was ten hours.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.1
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• pp.144-150
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• 2020

This paper presents a numerical study on the design of composite head geometry used for compound processing machine. In order to achieve an optimum composite head geometry and to explain the interactions between the different geometric configurations, three dimensional computational fluid dynamics and design of experiment methods have been applied. From the 2k factorial design results, the most important design variable was found and the performance of the composite head was improved compared to the reference model.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.5
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• pp.157-165
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• 2017

The high-pressure resin transfer molding (HP-RTM) technology has been commercialized for fast production of fiber reinforced composite materials. The high-pressure mixing head was one of the most core component of the HP-RTM process. In this study, a mixing head was systematically designed, manufactured and evaluated. This mixing head was composed of a nozzle, a mixing chamber, a cleaning piston part, and an internal mold release part. In actual, a straight-type structure was newly designed instead of the conventional L-type structure for improving the maximum mixing pressure and mixing ratio precision. The performance of mixing head was showed maximum mixing pressure of 15.22MPa and mixing ratio precision of 0.12%. CFRP molding experiments were successfully obtained a 6~11 laminating carbon sheet using HP-RTM presses and specimen molds.

• Journal of Trauma and Injury
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• v.33 no.1
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• pp.48-52
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• 2020

Composite skull defects in patients with severe head injuries are very challenging to manage. The dilemma when deciding whether to perform a definitive reconstruction is how long to wait for physiological recovery before an intervention complicates the situation. The inability of such patients to tolerate prolonged anesthetic exposure is a driving factor for performing the minimal intervention necessary to facilitate recovery. Herein, we present a case involving the successful immediate reconstructive treatment of a severely head-injured adolescent with a composite scalp defect secondary to trauma. A 14-year-old boy sustained a severe head injury from a motor vehicle accident with a composite scalp defect in the right fronto-parietal region. The frontal lobe was exposed, and the right eye was crushed and devitalized. The patient was deeply unconscious for 3 days, without any significant improvements before reconstructive surgery was proposed due to fear of possible meningitis resulting from the exposure of brain structures. We successfully managed the patient with a fronto-parieto-occipital flap, after which the patient promptly recovered consciousness.

• Proceedings of the Korean Magnestics Society Conference
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• 1995.10a
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• pp.82-83
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• 1995

• Korean Journal of Head & Neck Oncology
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• v.15 no.1
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• pp.35-39
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• 1999

Objectives: The treatment for squamous cell carcinoma of the tonsil remains controversial. Surgery or radiation therapy alone is effective in treating early tonsil cancer, but results with single treatment modality in advanced disease have been disappointing. We retrospectively analyzed 37 patients with advanced squamous cell carcinoma of the tonsil for two treatment modalities in an effort to identify more efficacious therapeutic options. Materials and Methods: From 1990 through 1997, 37 patients who were treated primarily with surgery, were retrospectively sudied. The patients were grouped into two groups according to the method of treatment, extended tonsillectomy followed by irradiation and/or postradiation neck dissection(Group I) and a combination of composite resection and postoperative radiation(Group II). Results: The three year disease-tree survival in patients with stage IV lesions was 59.09% for the Group I patients, and 56.25% for the Group II patients. This difference was not statistically significant(p=0.775). The primary tumor recurrence rate in Group I was 16.7% in contrast to 23.1% for Group II. The local recurrence rate in the neck was 16.7% for the Group I patients and 23.1% for the Group II patients. There was no significant difference in the frequency of recurrences in the primary or neck in the patients treated with extended tonsillectomy or composite resection(p=0.639). Fistula formation and aspiration occurred in four patients after composite resection. Additionally, there were three trismus, one soft tissue necrosis, and one velopharyngeal insufficiency. Major complications were not observed in the patients treated with extended tonsillectomy and irradiation: velopharyngeal insufficiency was observed in eight patients and soft tissue necrosis in two patients. Conclusion: Extended tonsillectomy followed by irradiation may be an effective therapy with low morbidity in selected patients with tonsil cancer.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.365-366
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• 2002

The sliding wear behavior of ultra high molecular weight polyethylene (UHMWPE) was examined on a novel low temperature degradation-free zirconia/alumina composite material and conventional alumina and zirconia ceramics used for femoral head in total hip joint replacement. The wear of UHMWPE pins against these ceramic disks was evaluated by performing linear reciprocal sliding and repeat pass rotational sliding tests for one million cycles in bovine serum. The weight loss of polyethylene against the novel low temperature degradation-free zirconia/alumina composite disks was much less than those against conventional ceramics for all tests. The mean weight loss of the polyethylene pins was more io the linear reciprocal sliding test than in the repeal pass rotational sliding lest for all kinds of disk materials. Neither the coherent transfer film nor the surface damage was observed on the surface of the novel zirconia/alumina composite disks during the test. The observed r,'stilts indicated that the wear of the polyethylene was closely related to contacting materials and kinematic motions. In conclusion, the novel zirconia/alumina composite leads the least wear of polyethylene among the tested ceramics and demonstrates the potential as lhe alternative materials for femoral head in total hip joint replacement.

• Transactions on Electrical and Electronic Materials
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• v.16 no.2
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• pp.74-77
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• 2015

The cure kinetics of a neat epoxy system and epoxy/silica composite were investigated by DSC analysis. A cycloaliphatic type epoxy resin was diglycidyl 1,2-cyclohexanedicarboxylate and curing agent was anhydride type. To estimate kinetic parameters, the Kissinger equation was used. The activation energy of the neat epoxy system was 88.9 kJ/mol and pre-exponential factor was 2.64×10¹² min⁻¹, while the activation energy and pre-exponential factor for epoxy/silica composite were 97.4 kJ/mol and 9.21×10¹² min⁻¹, respectively. These values showed that the silica particles have effects on the cure kinetics of the neat epoxy matrix.

• Mycobiology
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• v.30 no.1
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• pp.41-46
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• 2002

Composite vegetable crops grown in greenhouses and open fields in Korea were surveyed from 1995 to 1999. Occurrence of Sclerotinia rot was observed in 123 of 277 lettuce fields, in 11 of 18 head lettuce fields, in 12 of 14 endive fields, and in 4 of 38 garland chrysanthemum fields surveyed during the growing seasons. The disease most severely occurred up to 80% on lettuce. Incidence of the disease was as high as 20% at its maximum on endive and garland chrysanthemum but relatively low on head lettuce. Symptoms of the disease developed on leaves of all the composites, crowns of lettuce and head lettuce, and stems of garland chrysanthemum. Out of 240 isolates of Sclerotinia species obtained from the diseased composites, 169 isolates were identified as Sclerotinia sclerotiorum, and the others as S. minor based on their morphological and cultural characteristics. S. sclerotiorum was isolated from all the composites, and S. minor only from lettuce and endive. Eight isolates of S. sclerotiorum and four isolates of S. minor were tested for their pathogenicity to the composites by artificial inoculation. All the isolates of the two Sclerotinia spp. induced rot symptoms on the plants of the composites by artificial inoculation, which were similar to those observed in the fields. The pathogenicity tests revealed that there is no significant difference in virulence of the isolates to the composites and in susceptibility of the composites to the isolates.