• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.81-82
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• 2009

This paper introduces a gate drive IC for power modules with shoot-through immunity. A new approach uses a bootstrap diode as a high-side voltage bias and a level shift function at the same time. Therefore, the gate drive circuit becomes a simple and low-cost without conventional level shift functions such as HVIC(High-Voltage IC), optocoupler and transformer. The proposed gate drive IC is designed and fabricated using the Dongbu-Hitek's 0.35um BD350BA process. It has been tested and verified with IGBT modules.

• Vacuum Magazine
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• v.2 no.2
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• pp.12-16
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• 2015

Organic photovoltaics (OPVs) have attracted significant interest in an interdisciplinary research field for the decades as a next-generation photovoltaic device due to their unique advantages. One of requirements for OPVs having high power conversion efficiency is the favorable energy level alignment between the electrode/organic and organic/organic interfaces to manage the exciton dissociation and improve the charge transport. In this review, strategies to enhance the OPV performance by controlling the energy level alignment are discussed. The insertion of an exciton blocking layer leads to the efficient dissociation of photogenerated excitons at the donor/acceptor interface enhancing the short-circuit current density. The choice of a donor having a high ionization energy and an acceptor having a low electron affinity increases the open-circuit voltage. The insertion of an appropriate work function modifier which reduces the charge injection barrier removes the S-kink in current density-voltage characteristics of OPVs and improves the fill factor. This review would give a valuable guide to design the efficient OPV structure.

• International Journal of Advanced Culture Technology
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• v.8 no.4
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• pp.8-17
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• 2020

This study aims to draw up comprehensive ethical management practices so that companies can be reborn as high-quality companies not only at the level of management efficiency but also at the level of corporate integrity. -The main focus of in this study is as follows: To curb corrupt practices in the corporate sector, it is necessary to strengthen the monitoring function and accountability system of audits (internal audits, full-time audits, audit committees, external audits). In order for these system improvements to be made reliably, it is necessary to periodically measure and evaluate employee satisfaction with the overall personnel system.

• Journal of Gifted/Talented Education
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• v.25 no.1
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• pp.119-138
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• 2015

This study analyzed the academic achievements on above-level testing of mathematics, physics, chemistry, and English in newly entering students of science specialized high schools. It can be expected that newly students of science high specialized schools have reached ceiling level in the middle school mathematics and science academic scores. Above-level testing(or off-level testing) is a test tool used to evaluate student's ability which are above-grade level. In this study, above-level testing tools were used to develop the same type examination paper of the 2013 Korean College Scholastic Ability Test(CSAT) in mathematics, physics, chemistry, and English. The conclusions of this study were as follow: First, the academic achievement level of science specialized high school freshmen were higher the average level of general high school senior because that over 50% of them are within the 5 grade of CSAT in mathematics, physics, and chemistry. In English, 19.3% science specialized high school freshmen have reached within the 5 grade of CSAT. Second, as a result of examining characteristics of academic achievement with respect to units of subjects, in mathematics, it was showed that the academic achievement of 'continuity and limit of a function' unit was higher, 'statistics' unit was lower. In physics, the academic achievement of 'Electricity and Magnetism' unit was higher, 'Waves and particles' unit was lower. In chemistry, the academic achievement of 'compounds in life' unit was higher, 'Air' unit was lower. In English, the academic achievement of 'practical sentence' of reading area was higher, 'Sentence' of writing area was lower. In conclusion, above-level testing provided a good strategy for identifying and determining appropriate programming interventions for gifted students who are two or more grade levels above their age-mates in achievements, aptitude, or ability.

• Korean Journal of Veterinary Service
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• v.22 no.1
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• pp.61-70
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• 1999

This study is concerned with assessment of diethylnitrosamine(DEN) induced liver cell carcinogenesis by measurement of changes preceding the development of neoplasms. Therefore, it was undertaken to investigate the changes of liver-specific enzyme activities in rats (Sprague-Dawley) by ad libitum feeding of DEN. And also, as another objective index in urine, the level of urinary biopterin was measured by high performance liquid chromatography(HPLC) method. The results were as follows ; 1. Minor behavioral change, brittleness of hair and decreased amount of water and diet intake were observed in rats 7 weeks after DEN administration. 2. The body and liver weights were significantly(p<0.05) decreased in rats 11 weeks after DEN administration. 3. The ratio of liver weight to body weight was rather stable and not significantly decreased in the all treatment groups. 4. The liver specific enzyme activities(AST, ALT,$\gamma$-GTP) were significantly(p<0.05) increased in all treatment groups compared to control group. 5. Compared to normal level, urine biopterin level was significantly (p<0.05) increased in all treatment groups(p<0.05). In conclusion, this result confirmed that the DEN was one of the potent hepatocarcinogens. In experimental model of rats exposed to DEN, the results indicated that values of liver specific enzyme activities(AST, ALT, $\gamma$-GTP) and urine biopterin level could be useful complementary tumor indices.

• The Journal of Korean Physical Therapy
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• v.29 no.5
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• pp.259-264
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• 2017

Purpose: This study examined the effects of a positioning education program through the brochure or oral explanations for the parents of premature infants with a brain lesion and investigated the satisfaction level of physical therapy of parents of premature infants with a brain lesion. Methods: Forty parents of premature infants with a brain lesion participated in this study. The recruited premature infants were randomized into groups A (n=20) and B (n=20) for the purpose of the positioning education method through brochure or oral explanations. The level of satisfaction and recognition for the positioning education program was investigated by the parents of 12 month old infants. The gross motor function, measure-88, was examined at three months, six months, nine months, and twelve months of the corrected age. Results: No significant differences in the recognition of the position education program, level of satisfaction of the environment, and the attitude of the therapist were noted (p>0.05). Significantly high levels of satisfaction with the program of group B given the brochure were noted. The gross motor function measure-88 was also similar in both groups (p<0.05). Conclusion: This study suggests that the parents were satisfied with the positioning education program of the brochure. The differences in educational methods did not affect the development of premature infants.

• Steel and Composite Structures
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• v.47 no.5
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• pp.569-585
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• 2023

This paper proposes an efficient approach for the structural topology optimization of bi-directional functionally graded structures by incorporating popular radial basis functions (RBFs) into an implicit level set (ILS) method. Compared to traditional element density-based methods, a level set (LS) description of material boundaries produces a smoother boundary description of the design. The paper develops RBF implicit modeling with multiquadric (MQ) splines, thin-plate spline (TPS), exponential spline (ES), and Gaussians (GS) to define the ILS function with high accuracy and smoothness. The optimization problem is formulated by considering RBF-based nodal densities as design variables and minimizing the compliance objective function. A LS-RBF optimization method is proposed to transform a Hamilton-Jacobi partial differential equation (PDE) into a system of coupled non-linear ordinary differential equations (ODEs) over the entire design domain using a collocation formulation of the method of lines design variables. The paper presents detailed mathematical expressions for BiDFG beams topology optimization with two different material models: continuum functionally graded (CFG) and mechanical functionally graded (MFG). Several numerical examples are presented to verify the method's efficiency, reliability, and success in accuracy, convergence speed, and insensitivity to initial designs in the topology optimization of two-dimensional (2D) structures. Overall, the paper presents a novel and efficient approach to topology optimization that can handle bi-directional functionally graded structures with complex geometries.

• Journal of Korean Academy of Nursing
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• v.29 no.3
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• pp.639-655
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• 1999

An explanatory design was employed to identify the relationship of physical, emotional & social readjustment and social support of post hospitalized stroke patients and their caregivers. A convenient sample of 254 patients who given follow-up care at the outpatient department after discharge and 225 caregivers were recruited. Mental Status Questionnaire (MSQ), Social Support Inventory Stroke Survivors (SSISS), Illness intrusiveness(II), Instument Activity of Daily Living(IADL), Center of Epidemilogic Studies-Depression(CES-D), social activity and caregiver burden were used for measurement in this study. Results showed patient's physical level measured by IADL and psychological level measured by depression were high. But social activity was low. Cognitive function, depression & social activity were not significantly different by the posthospitalized period, but IADL was. The source of professional support was mostly the physician at the outpatient department. The family support was found significantly related to patient's depression & social activity and caregiver's subjective burden. Professional support was found significantly related to patient's IADL & depression. Illness intrusiveness as a mediating variable was a sig nificantly predicting power on patient's IADL & depression. The path analysis was used to identify the variables to predict the physical, emotional, and social status of patients. As a result, patient's age, cognitive function, illness intursiveness and professional support significantly predicted the level of IADL ; patient's cognitive function, illness intrusiveness and family support significantly predicted the level of depression ; and patient's age and family support significantly predicted the level of social activity of posthospitalized stroke patients. Based upon these results, the rehabilitation programs to reduce the illness intrusiveness and improve cognitive funtion were recommended for the readjustment of the stroke patients. This model of the readjustment of the posthospitalized stroke patients is recommended as the framework for care of the stroke patients.

• Journal of Life Science
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• v.19 no.6
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• pp.825-831
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• 2009

The purpose of this study was to investigate the influences of immune function and respiratory system on aerobic exercise of 75 %HRmax intensity in an exposed acute hypobaric hypoxic environment. The subjects were 20 male college students, 10 of which were soccer players (19.6${\pm}$0.8 yr, BMI 22.3${\pm}$1.0, V02max 56.5${\pm}$4.8 mljkgjmin) and 10 general students (22.2${\pm}$2.3 yr, BMI 22.7${\pm}$2.1, $VO_{2max}$ 50.5${\pm}$6.6 ml/kg/min). Items of measurement after exercise on level and high altitude were $O_{2}$, $CO_{2}$, ventilation (VE), respiratory frequency, respiratory quotient, RBC, MCV, MCH, MCHC, Hb, Hct, reticulocyte, WBC, neutrophil, lymphocyte, monocyte, basophil, and immunoglobulin (IgA, IgD, IgG, IgM). As the result of the verifying hypothesis, these results may suggest three new findings: first, to produce hypoxic ventilatory depression not only at level land but also at 3,000 m high altitude during 30 minute aerobics exercise of 75 %HRmax intensity, second to be more excellent for soccer players in adaptation and sensibility on response of respiratory system at high altitude, and third, to change each other by regular exercise habits or altitude in the monocyte.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.4
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• pp.19-28
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• 2021

Purpose : The purpose of this study was to apply manual lymphatic drainage (MLD) and high-frequency diathermy (HFD) to patients with axillary web syndrome (AWS), one of the side effects of breast cancer surgery, and to treat upper extremity pain, volume, function of the upper extremity, (joint range of motion; ROM, disabilities of the arm, shoulder and hand; DASH) and quality of life before and after treatment. It is to determine the effect of treatment by checking the level change. Methods : This study is a case series. A total of 5 patients diagnosed with AWS after breast cancer surgery voluntarily participated in this study. The intervention program consisted of stretching, MLD and HFD. It was conducted 3 times a week for 30 minutes for 4 weeks. In order to compare the effects of pain (numeric pain rating scale; NPRS), volume, upper limb function (ROM, DASH) and quality of life (the European organization for research and treatment of cancer quality of life questionnaire-breast, EORTC QLQ-BR23) evaluations were compared before and after 4 weeks of intervention. All measured variables were analyzed and expressed as mean, standard deviation and percentage. Results : The shoulder NPRS level of the subjects in all case groups decreased, the volume decreased and the shoulder flexion, abduction ROM increased. It showed improvement in DASH and quality of life, QLQ-BR23. Conclusion : After breast cancer surgery, we confirmed the possibility that MLD and HFD treatments could be effective in improving pain, decreasing volume, increasing upper extremity function, and quality of life for patients who have difficulties with AWS. The possibility has been confirmed, and additional research is needed by increasing the number of participants in the experiment in the future.