• Journal of Astronomy and Space Sciences
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• v.23 no.4
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• pp.355-372
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• 2006

Mission opportunities and trajectory characteristics for the future Korean Mars mission have designed and analyzed using KSIV-III(Korea Space Launch Vehicle-III). Korea's first space center, 'NARO space center' is selected as a launch site. For launch opportunities, year 2033 is investigated under considering the date of space center's completion with KSLV series development status. Optimal magnitude of various maneuvers, Trans Mars Injection (TMI) maneuver, Trajectory Correction Maneuver (TCM), Mars Orbit Insertion (MOI) maneuver and Orbit Trim Maneuver(OTM), which are required during the every Mars mission phases are computed with the formulation of nonlinear optimization problems using NPSOL software. Finally, mass budgets for upper stage (launcher for KSIV-III and spacecraft are derived using various optimized maneuver magnitudes. For results, daily launch window from NARO space center for successful Korean Mars mission is avaliable for next 27 minutes starting from Apr. 16. 2033. 12:17:26 (UTC). Maximum spacecraft gross mass which can delivered to Mars is about 206kg, with propellant mass of 109kg and structure mass of 97kg, when on board spacecraft thruster's Isp is assumed to have 290 sec. For upper stage, having structure ratio of 0.15 and Isp value of 280 sec, gross mass is about 1293kg with propellant mass of 1099kg and structure mass of 194kg. However, including 10% margins to computed optimal maneuver values, spacecraft gross mass is reduced to about 148kg with upper stage's mass of 1352kg. This work will give various insights, requiring performances to developing of KSIV-III and spacecraft design for future Korean Mars missions.

• The Journal of the Korean bone and joint tumor society
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• v.1 no.2
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• pp.205-209
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• 1995

A desmoid tumor is a locally aggressive growth of connective tissue origin which infiltrates the surrounding tissue and has a marked tendency for recurrence. And so it was also called as an aggressive fibromatosis, musculofascial fibromatosis or fibrosarcoma etc. Thirteen cases of desmoid tumor was treated since 1980, and their retrospective study was done with 79 months of follow-up after initial surgical excision. The female was involved in 12 cases(one male) with the age ranged from 7-50 years, average 28 years, and seven patients in third decade. A slowly growing mass was excised on average 4 months after first notice of the mass, but their margins are not demarcated clearly in most cases. Wide excision in 12 cases was done, but wide excision and saphenous vein graft was performed in one case because of invasion of posterior tibial artery by tumor mass. The tumor was found on extraabdominal region in 8 cases(61.5%) but 5 cases in abdominal wall(38.5%). The recurrence rate was high(6/13, 46.2%), and 11 times in 6 patients were recurred(average 1.8 times), within 27 months of initial excision. Six cases of recurrence were treated with wide excision again in 3 cases, wide excision combined with radiotherapy(4,000-6,000cGy) in 4 cases and wide excision with chemotherapy in one case. During the follow-up for average 21 months after treatment, no recurrences are found. Tumor remission periods without recurrence are average 67 months in all, and 11 years in longest case. Histologically it was very mimic with fibrosarcoma but could be differentiated with Trichrome stain, and their findings are not changed after recurrence.

• Radiation Oncology Journal
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• v.28 no.3
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• pp.177-183
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• 2010

Purpose: Simulation using computed tomography (CT) is now widely available for radiation treatment planning for breast cancer. It is an important tool to help define the tumor target and normal tissue based on anatomical features of an individual patient. In Korea, most patients have small sized breasts and the purpose of this study was to review the margin of treatment field between conventional two-dimensional (2D) planning and CT based three-dimensional (3D) planning in patients with small breasts. Materials and Methods: Twenty-five consecutive patients with early breast cancer undergoing breast conservation therapy were selected. All patients underwent 3D CT based planning with a conventional breast tangential field design. In 2D planning, the treatment field margins were determined by palpation of the breast parenchyma (In general, the superior: base of the clavicle, medial: midline, lateral: mid - axillary line, and inferior margin: 2 m below the inframammary fold). In 3D planning, the clinical target volume (CTV) ought to comprise all glandular breast tissue, and the PTV was obtained by adding a 3D margin of 1 cm around the CTV except in the skin direction. The difference in the treatment field margin and equivalent field size between 2D and 3D planning were evaluated. The association between radiation field margins and factors such as body mass index, menopause status, and bra size was determined. Lung volume and heart volume were examined on the basis of the prescribed breast radiation dose and 3D dose distribution. Results: The margins of the treatment field were smaller in the 3D planning except for two patients. The superior margin was especially variable (average, 2.5 cm; range, -2.5 to 4.5 cm; SD, 1.85). The margin of these targets did not vary equally across BMI class, menopause status, or bra size. The average irradiated lung volume was significantly lower for 3D planning. The average irradiated heart volume did not decrease significantly. Conclusion: The use of 3D CT based planning reduced the radiation field in early breast cancer patients with small breasts in relation to conventional planning. Though a coherent definition of the breast is needed, CT-based planning generated the better plan in terms of reducing the irradiation volume of normal tissue. Moreover it was possible that 3D CT based planning showed better CTV coverage including postoperative change.

• The KSFM Journal of Fluid Machinery
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• v.4 no.1 s.10
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• pp.7-13
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• 2001

In developing a multistage compressor, the stage matching is one of the critical design issues. The mismatching can be often observed even if each stage has been proven good and then used as part of a compression system. A good matching among the stages can be achieved by changing various design parameters (i.e., passage cross sectional areas, blades angles, stagger angles, curvature, solidity, etc.). Therefore, designers need to find out what parameters must be changed and how much. In this study, a method to search the design parameters for optimum stage matching has been used based on an 1-D mathematical model of a compressor, which uses the data obtained from the preliminary test to identify the design parameters. This methodology is applied with a two-stage axial compressor, which was originally designed for a helicopter gas turbine engine. After identifying design parameters using preliminary test data, an optimization process has been employed to achieve the best matching between the stages (i.e., maximum efficiency of the compressor at its operation modes within a given range of the rotor speed under given restrictions for required stall margins and mass flow). 3-D flow calculations have been performed to confirm the usefulness of the corrections based on the 1-D mathematical model. Calculational results agree well with the experimental data in view of the performance characteristics. Some promising results were produced through the methodology proposed in this paper in conjunction with flow calculations.

• Investigative Magnetic Resonance Imaging
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• v.21 no.1
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• pp.38-42
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• 2017

Schwannomas are mostly solid tumors, some of which may contain cystic degenerations or hemorrhages. However, a schwannoma seen as a purely hemorrhagic cystic tumor is very rare. A 63-year-old woman was referred to the hospital due to a slow-growing mass (present for about 5 years) on her right thigh. She complained about vague pain but without neurologic symptoms such as numbness or tingling sensations. MR images showed an oval lesion with defined margins surrounded by the rectus femoris, vastus lateral, and the vastus intermedius. It was characterized as a multilocular cystic lesion composed of hemorrhagic fluid. In addition, the benign hemorrhagic cystic lesion was differentially diagnosed by radiological techniques as a hemorrhagic ganglion cyst. The lesion was surgically excised and, based on pathological features, was diagnosed as being a schwannoma. We report a purely hemorrhagic cystic schwannoma located in an intermuscular plane.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3185-3190
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• 2016

Background: This study was designed to compare radioguided versus routine wire localization of nonpalpable non-malignant breast lesions in terms of efficacy for complete excision, ease of use, time saving, and cosmetic outcome. Materials and Methods: Patients with non-palpable breast masses and non-malignant core biopsy results who were candidates for complete surgical lumpectomy were enrolled and randomly assigned to radioguided or wire localization groups. Radiologic, surgical, and pathologic data were collected and analyzed to determine the difficulty and duration of each procedure, ease of use, accuracy, and cosmetic outcomes. Results: This prospective randomized study included 60 patients, randomly divided into wire guided localization (WGL) or radioguided occult lesion localization (ROLL) groups. The mean duration of localization under ultrasound guidance was shorter in the ROLL group (14.4 min) than in the WGL group (16.5 min) (p<0.001). The ROLL method was significantly easier for radiologists (p=0.0001). The mean duration of the surgical procedure was 22.6 min (${\pm}10.3min$) for ROLL and 23.6 min (${\pm}9.6min$) for WGL (p=0.6), a non-significant difference. Radiography of the surgical specimens showed 100% lesion excision with clear margins, as proved by pathologic examination, with both techniques. The surgical specimens were slightly heavier in the ROLL group, but the difference was not significant (p=0.06). Conclusions: The ROLL technique provides effective, fast, and simple localization and excision of non-palpable non-malignant breast lesions.

• Archives of Plastic Surgery
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• v.35 no.1
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• pp.100-103
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• 2008

Purpose: Eccrine porocarcinoma is a very rare, potentially fatal tumor which arises from the intraepidermal portion of the eccrine sweat ductal apparatus. It does not have a characteristic clinical feature but does have a high incidence of metastasis. It may be developed de novo or in a preexisting benign eccrine poroma. It usually affects older people and is located most commonly on lower extremities. We report a rare case of eccrine porocarcinoma which developed on the back without metastasis. Methods: The patient was a 94-year-old woman who showed a painful, ulcerated, dark brown colored polypoid $3.5{\times}3.0cm$ sized mass on the back for 3 years. We totally excised the lesion including normal tissue. Results: After wide excision of the lesion, pathologist reported an eccrine porocarcinoma. Histopathologic findings reveal that the classic type of eccrine gland carcinoma, eccrine porocarcinoma. Immunocytochemical studies showed a positive reactivity to anti-EMA antibody and anti-CEA antibody. Conclusion: Authors experienced a rare case of primary eccrine porocarcinoma on the back. Because of the propensity to develop local recurrence, wide excision of the primary tumor with histologic confirmation of negative margins represents the only curative treatment regimen for eccrine porocarcinoma.

• Economic and Environmental Geology
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• v.24 no.1
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• pp.9-20
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• 1991

Gusi pyrophyllite deposit is located in the Haenam volcanic field in the southwestern part of the Korea Peninsula. This area is known for the occurrences of pyrophyllite, alunite and dickite. This volcanic field is composed of andesite, rhyolite and pyroclastic rocks of late Cretaceous age The pyroclastic rocks are hydrothermally altered to pyrophyllite and kaolin minerals forming the Gusi deposits. The hydrothermally altered rock can be classified into the following zones on the basis of their mineral assemblages: quartz, pyrophyllite, dickite and illite-smectite zones, from the centre to the margins of the alteration mass. Such mineral assemblages indicate that the country rocks, most of which are the lower Jagguri Tuff, were altered by strongly acidic hydrothermal solutions with high aqueous silica and potassium activity and that the formation temperature of pyrophyllite is higher than $265^{\circ}C$. The mechanism of the hydrothermal alteration is considered to be related to felsic magmatism.

• Korean Journal of Head & Neck Oncology
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• v.24 no.2
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• pp.203-206
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• 2008

Objectives：DFSP(Dermatofibrosarcoma protuberans) is an uncommon, slowly growing, locally invasive malignant tumor that usually presents as a painless, often long-standing mass arising in the dermis of skin. It occurs most frequently on the trunk and proximal parts of the limbs, less commonly in the head and neck region and has a frequent tendency to recur after surgical excision. Clinically, the initial appearance of the tumor similar to that of benign tumor such as keloid and dermatofibroma. Therefore, accurate clinical diagnosis and adequate surgical excision are important. Materials and Methods：We experienced 6 patients of DFSP in head and neck during the recent 6 years, 5 male and 1 female patients. The age of the patients ranged from 31 to 66. As reconstructive methods, the authors used cervicofacial flap, trapezius musculocutaneous flap, TRAM flap, anterolateral thigh free flap and skin graft. Results：The patients were followed up after operation from 24 to 79 months and all remained free of disease except one case, who occurred at forehead area. Conclusion：We present the experience of 6 cases of DFSP occurred in head and neck. We obtained satisfactory results with appropriate diagnosis and treatment which wide excision with surgical margins 3-5cm. We also present an operative plan of this locally aggressive and highly recurrent tumor.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.6
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• pp.570-574
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• 2005

Keratoacanthoma is a benign, self-limited epithelial lesion that closely resembles Squamous cell carcinoma(SCC). Keratoacanthoma occur primarily exposed skin in male patients over 45 years of ages. although etiology is unknown, sunlight, genetic, and human papillomavirus factor have been considered. in clinical feature, rapid enlargement occurs over 4$\sim$8 weeks, resulting ultimately in a hemispheric, firm, elevated, asymptomatic nodule that contains a central plug of keratin. When fully developed, the keratoacanthoma contains a core of keratin surrounded by a concentric collar of raised skin. Over the next 4$\sim$8 weeks, static lesion persists. Then undergoes spontaneous regression over the next 6$\sim$8weeks period by expulsion of the keratin core with resorption of the mass. In histologic feature, Keratoacanthoma consists of hyperplastic squamous epithelium growing into the underlying connective tissue. The surface is covered by a thickened layer of parakeratin with central plugging. Epithelium cell shows dysplastic features and the margins the normal adjacent epithelium is elevated. The differential diagnosis includes SCC. Keratoacanthoma present as a exophytic lesion with horny keratin occupying a depression on the top of the lesion, persists static period and undergoes rapid growth compared with SCC. Keratoacanthoma is usually treated by surgical excision or curettage of the base, spontaneous regression does not occur in every case. A 60 years old male who present facial lesion visit our hospital and surgical excision was done. Biopsy result was keratoacanthoma. We report case with review of literatures.