• Journal of Korean Neurosurgical Society
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• v.45 no.6
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• pp.381-385
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• 2009

The first case of intracranial metastases of a cervical intramedullary low-grade astrocytoma without malignant transformation in adult is presented in this report. Seven years ago, a 45 year-old male patient underwent biopsy to confirm pathologic characteristics and received craniocervical radiation and chemotherapy for a grade II astrocytoma in the cervical spinal cord. Two years later, posterior fusion was necessary for progressive kyphosis in the cervical spine. He was well for approximately 7 years after the primary surgery. Two months ago, he presented with partial weakness and incoordination with gait difficulty. MRI Scan demonstrated multiple small lesions in the cerebellar vermis and left hemisphere. After suboccipital craniectomy and posterior cervical exposure, the small masses in the cerebellar vermis and hemispheres were excised to a large extent by guidance of an intraoperative navigation system. The tumor at the cervical and brain lesions was classified as an astrocytoma (WHO grade II). When a patient with low-grade astrocytoma in the spinal cord has new cranial symptoms after surgery, radiaton, and chemotherapy, the possibility of its metastasis should be suspected because it can spread to the intracranial cavity even without malignant transformation as shown in this case.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.32 no.3
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• pp.77-86
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• 2019

Objectives : By analyzing symptoms of tinnitus, we tried to find out the relationship between deficiency and excess(虛實) and visceral pattern identification(臟腑辨證). By testing Tinnitus Handicap Inventory(THI), we evaluated the quality of life of people suffering from various aspects of tinnitus, as well as comparing treatment efficiency. Methods : 52 patients were recruited in this study who was ill with tinnitus. They wrote out the questionnaire about tinnitus and the THI. Results : The vast majority of high-grade tiny noise patients are deficiency type(虛症). The vast majority of low-grade roar patients are excess type(實症). Tinnitus persistence and feeling of ear occlusion were prominent in low-grade roar patients. low-grade roar patients suggest that overall quality of life is lower than high-grade tiny noise patients. In terms of treatment efficiency, spleen-stomach weakness(脾胃虛弱)-type, stomach heat(胃熱)-type and phlegm-fire(痰火)-type was higher than kidney essence depletion(腎精虧損)-type and liver qi depression(肝氣鬱結)-type regardless of the aspect of tinnitus. Conclusions : The present study suggests that tinnitus pattern may be helpful in differentiating patients with tinnitus, and the effectiveness of treatment can be predicted through differentiation.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1708-1717
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• 2023

The grade analysis of lead-zinc ore is the basis for the optimal development and utilization of deposits. In this study, a method combining Prompt Gamma Neutron Activation Analysis (PGNAA) technology and machine learning is proposed for lead-zinc mine borehole logging, which can identify lead-zinc ores of different grades and gangue in the formation, providing real-time grade information qualitatively and semi-quantitatively. Firstly, Monte Carlo simulation is used to obtain a gamma-ray spectrum data set for training and testing machine learning classification algorithms. These spectra are broadened, normalized and separated into inelastic scattering and capture spectra, and then used to fit different classifier models. When the comprehensive grade boundary of high- and low-grade ores is set to 5%, the evaluation metrics calculated by the 5-fold cross-validation show that the SVM (Support Vector Machine), KNN (K-Nearest Neighbor), GNB (Gaussian Naive Bayes) and RF (Random Forest) models can effectively distinguish lead-zinc ore from gangue. At the same time, the GNB model has achieved the optimal accuracy of 91.45% when identifying high- and low-grade ores, and the F₁ score for both types of ores is greater than 0.9.

• Journal of the Korean Ceramic Society
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• v.32 no.1
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• pp.71-82
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• 1995

The weathered two-mica granite is widely distributed in Korea and called a kind of ground rock for kaolin. The major minerla compositions are consist of this quartz, feldspar, mica and clay mineral. At present, only a small portion of this granite is used as the material for the low-grade tile industry due to the low S.K. value and the high contents of impurities such as Fe2O3 and FeO. The low S.K. value is caused by feldspars not weathered to clay minerals. The refinement of this thus has been required for the recent shortage of the resources of high-grade one. This paper concerns an optimum hydrothermal treatment condition to refine the low-grade weathered two-mica granite of which impurities are feldspar mineral and Fe2O3. FeO components in using for the main material of ceramic industry. And then, from this result, we tried to fine out the basic formation mechanism of clay mineral from feldspar etc and develope the effectual utilization method of this.

• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.4274-4281
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• 2023

Blanket is of vital importance for engineering application of the fusion reactor. Nuclear heat deposition in materials is the main heat source in blanket structure. In this paper, the three-dimensional method for thermal-hydraulics/neutronics coupling analysis is developed and applied for the full-scale module of the helium-cooled ceramic breeder tritium breeding blanket (HCCB TBB) designed for China Fusion Engineering Test Reactor (CFETR). The explicit coupling scheme is used to support data transfer for coupling analysis based on cell-to-cell mapping method. The coupling algorithm is realized by the user-defined function compiled in Fluent. The three-dimensional model is established, and then the coupling analysis is performed using the paralleled Coupling Analysis of Thermal-hydraulics and Neutronics Interface Code (CATNIC). The results reveal the relatively small influence of the coupling analysis compared to the traditional method using the radial fitting function of internal heat source. However, the coupling analysis method is quite important considering the nonuniform distribution of the neutron wall loading (NWL) along the poloidal direction. Finally, the structure optimization of the blanket is carried out using the coupling method to satisfy the thermal requirement of all materials. The nonlinear effect between thermal-hydraulics and neutronics is found during the blanket structure optimization, and the tritium production performance is slightly reduced after optimization. Such an adverse effect should be thoroughly evaluated in the future work.

• Journal of Hydrogen and New Energy
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• v.31 no.1
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• pp.105-111
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• 2020

The organic Rankine cycle (ORC) and the Kalina cycle system (KCS) are being considered as the most feasible and promising ways to recover the low-grade finite heat sources. This paper presents a comparative exergetical performance analysis for ORC and Kalina cycle using ammonia-water mixture as the working fluid for the recovery of low-grade heat. Effects of the system parameters such as working fluid selection, turbine inlet pressure, and mass fraction of ammonia on the exergetical performance are parametrically investigated. KCS gives lower lower exergy destruction ratio at evaporator and higher second-law efficiency than ORC. The maximum exergy efficiency of ORC is higher than KCS.

• The Journal of the Korean bone and joint tumor society
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• v.10 no.2
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• pp.130-133
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• 2004

Low-grade fibromyxoid sarcoma (LGFMS) is very rarely seen, and it commonly arises from the deep soft tissues of the lower extremities. Histologically, it is characterized by the presence of bland spindle cells with mainly storiform pattern of growth, set in alternating areas with a myxoid or fibrous stroma. The immunohistochemical reaction of this tumor permits a positive diagnosis of low grade fibromyxoid sarcoma and allows its distinction from a number of other benign and malignant soft tissue tumor. We report this rare case together with the review of the literature.

• Journal of Chest Surgery
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• v.35 no.8
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• pp.638-641
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• 2002

Low grade fibromyxoid sarcoma is a recently recognized, uncommon soft tissue neoplasm. It has a tendency to develop in deep soft tissue of young adults and a possibility of local recurrence or distant metastasis. Diagnostic criteria have not been well defined and this tumor has not been accepted as a distinct entity. Histologically, it is characterized by the presence of bland spindle cells with mainly whorled pattern of growth, set in alternating areas with a myxoid or fibrous stroma. Careful consideration of the morphological and immunohistochemical features of this tumor permit a positive diagnosis of low grade fibromyxoid sarcoma and allow its distinction from a number of other benign and malignant soft tissue neoplasms. We experienced a low grade fibromyxoid sarcoma in chest wall and report this case with a review of the literature.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2007.05a
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• pp.227-230
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• 2007

The expansion of open education and the 7th revision of educational curriculum have brought big changes in the school facilities. In response to the integrated curriculum for the first and second grades of elementary school, various plans, such as open classroom, expanded classroom size, and the installation of multi-purpose space, have been attempted. However, such plans have appeared in the form of an open classroom--a uniform spatial composition. As a result, a plan for unit learning space to support the educational curriculum and activities for low grade levels is still insufficient. In the case of advanced countries, a lot of studies on space are being actively conducted to develop the creativity of children and to facilitate free-style learning, and such space is actually applied to a real educational environment. Therefore, this study will analyze the spatial composition of unit learning space for low grade level elementary schools in Korea. From the cases of advanced countries, a more concrete proposal will be suggested to diversify unit learning space for low grade levels.

• Journal of architectural history
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• v.25 no.3
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• pp.37-45
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• 2016

This study was to investigate the firing method of limestone in Joseon Dynasty, and analyze the physical chemical properties of lime mortars in Joseon Dynasty. This study was to manufacture and evaluate the firing experiment and mortar of Limestone by each sort in order to reproduce the traditional lime mortars in Joseon Dynasty, and investigate the behavior to improve physical properties according to the firing method of Limestone. This study has found out that there were screening criteria and standard of appropriate firing temperature about the Limestone in Joseon Dynasty. Accordingly, this study was to improve its strength through various additives and mixture. In particular, in case of Limestone, the black and blue Limestone were preferred, and most of domestic Limestones were low grade Limestone including the clay and took ivory white or blue with low whiteness. This study has shown that the low grade Limestone was mined by the surface mining compared with the high grade Limestone as underground mining method, and could be used because it was easy to mine relatively and there was possibility that Natural Hydraulic Lime(NHL) was used with the traditional lime mortars in Joseon Dynasty.