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Static Induction Transistor(SIT), Drive signal phase shift control, Induction heating
노채균,김동희,김종해,남승식,정원영,심광열 嶺南大學校 工業技術硏究所 1997 工業技術硏究所論文集 Vol.25 No.1
This paper proposed a novel SIT high frequency resonant inverter having drive signal phase shift control function. Phase control type inverters using SIT can realize a power conversion at the high switching frequency with low switching loss. Especially, the high output power can be obtained by connecting the output terminal of two unit inverters in series. The stability of system using protection circuit for over current and the automatic follow-up control for load variation by using PLL are presented. This inverter produces approximately sinusoidal waveform at a high frequency, ranging from 180 Khz to 220 Khz, and is applied to the 2KW induction heating. The operating characteristics of this inverter circuit are discussed from a theoretical point of view and compared with experimental results.
Phase-Shift를 이용한 시분할형 부하병렬 고주파 인버터의 특성해석에 관한 연구
조규판,원재선,김동희,노채균,원규식,심광열 영남대학교 공업기술연구소 2000 工業技術硏究所論文集 Vol.28 No.2
A half bridge time sharing type load parallel high frequency resonant inverter to give VVVF function in the inverter used as power source of induction heating at high frequency is presented in this paper. This proposed inverter can reduce distribution of the switching current because of using the current of serial resonant circuit to the input current of the parallel one and this paper also realize the output control of independence irrespective of the switching frequency using Phase-Shift. The analysis of the proposed circuit is generally described by using the normalized parameters. Also, the principle of basic operation and the its characteristics are estimated by the parameters, such as switching frequency, the variation of phase angle(φ) of Phase-Shift. It is certain that the proposed circuit will be used and expanded in the high frequency power supplies like induction heating systems.
고속전철 추진 시스템의 미끄럼 방지 제어기법에 관한 연구
황돈하,김동희,노채균,심광열,조규판,정원영 영남대학교 공업기술연구소 1999 工業技術硏究所論文集 Vol.27 No.2
Induction motor drive with PWM inverter control has been developed for Korean High Speed Railways. To improve traction performance, the anti-slip control(ASC) to recover adhesion must be considered. This paper describes a novel hybrid anti-slip control method for the induction motor drive. By introducing the vector control for drive system, quick response of the motor torque can be achieved when wheels are going to slip. A hybrid control scheme by mixing two conventional control methods (slip velocity feedback control and slip detection pattern control) for wheel slip and re-adhesion is proposed. This control method is simulated by motor drive, train load, and friction-creep models. The train running simulation results based on induction motor vector control with PWM inverter show that good re-adhesion characteristics are obtained.
Antiosteoporotic activity of ‘Dae-Bo-Won-Chun’ in the ovariectomized rats
Chae, Han-Jung,Kang, Jang-Sook,Kim, Jong-Hwan,Kim, Chul-Won,Yoo, Sim-Keun,Choi, Bom,Kim, Hyung-Min,Shin, Tae-Yong,Kim, Hyung-Ryong Kyung Hee Oriental Medicine Research Center 2000 International journal of oriental medicine Vol.1 No.1
The preventive effect of herbal formulation, ‘Dae-Bo-Won-Chun’(DBWC), on the progress of bone loss induced by ovariectomy (OVX) was studied in rats. From light microseopic analyses, a porous or erosive appearances were observed on the surface of trabecular bone of tibia in ovariectomized rats. Whereas those of the same bone in sham rats were composed of fine particles. The trabecular bone area and trabecular thickness in ovariectomized rats decreased by 50% from those in sham-operated rats, these decreases were completely inhibited by administration of DBWC at concentration of 10mg/kg per day for 7 weeks. The mechanical strength in femur neck was decreased by ovariectomy, and this was significantly suppressed by the administration of DBWC. Serum phosphorus, alkaline phosphatase, and thyroxine levels in ovariectomized rats were increased compared to those in sham-operated rats, and increases were completely inhibited by the administration of DBWC. These results strongly suggest that DBWC is effective in preventing the development of bone loss induced by ovariectomy in rats.
Jae Kyeom Sim,Sang-Min Lee,Hyung Koo Kang,Kyung Chan Kim,김영삼,김윤성,리원연,Sunghoon Park,So Young Park,박주희,Yun Su Sim,이광하,이연주,Jin Hwa Lee,Heung Bum Lee,Chae-Man Lim,Won-Il Choi,Ji Young Hong,Won Jun Song,Ge 대한내과학회 2022 The Korean Journal of Internal Medicine Vol.37 No.3
Background/Aims: There are few studies describing contemporary status of mechanical ventilation in Korea. We investigated changes in management and outcome of mechanical ventilation in Korea. Methods: International, prospective observational cohort studies have been conducted every 6 years since 1998. Korean intensive care units (ICUs) participated in 2010 and 2016 cohorts. We compared 2016 and 2010 Korean data. Results: Two hundred and twenty-six patients from 18 ICUs and 275 patients from 12 ICUs enrolled in 2016 and 2010, respectively. In 2016 compared to 2010, use of non-invasive ventilation outside ICU increased (10.2% vs. 2.5%, p = 0.001). Pressure-control ventilation was the most common mode in both groups. Initial tidal volume (7.1 mL/kg vs. 7.4 mL/kg, p = 0.372) and positive end-expiratory pressure (6 cmH2O vs. 6 cmH2O, p = 0.141) were similar, but peak pressure (22 cmH2O vs. 24 cmH2O, p = 0.011) was lower in 2016. More patients received sedatives (70.7% vs. 57.0%, p = 0.002) and analgesics (86.5% vs. 51.1%, p < 0.001) in 2016. The awakening (48.4% vs. 31.0%, p = 0.002) was more frequently attempted in 2016. The accidental extubation rate decreased to one tenth of what it was in 2010 (1.1% vs. 10.2%, p < 0.001). The ICU mortality did not change (31.4% vs. 35.6%, p = 0.343) but ICU length of stay showed a decreasing trend (9 days vs. 10 days, p = 0.054) in 2016. Conclusions: There were temporal changes in care of patients on mechanical ventilation including better control of pain and agitation, and active attempt of awakening.
Sim, Hyun-Jaung,Kim, Min-Hye,Bhattarai, Govinda,Hwang, Jae-Won,So, Han-Sol,Poudel, Sher Bahadur,Cho, Eui-Sic,Kook, Sung-Ho,Lee, Jeong-Chae Korean Society for Molecular and Cellular Biology 2021 Molecules and cells Vol.44 No.4
Numerous studies highlight the potential benefits potentials of supplemental cartilage oligomeric matrix protein-angiopoietin-1 (COMP-Ang1) through improved angiogenic effects. However, our recent findings show that excessive overexpression of COMP-Ang1 induces an impaired bone marrow (BM) microenvironment and senescence of hematopoietic stem cells (HSCs). Here, we investigated the underlying mechanisms of how excessive COMP-Ang1 affects the function of BM-conserved stem cells and hematopoiesis using K14-Cre;inducible-COMP-Ang1-transgenic mice. Excessive COMP-Ang1 induced peripheral egression and senescence of BM HSCs and mesenchymal stem cells (MSCs). Excessive COMP-Ang1 also caused abnormal hematopoiesis along with skewed differentiation of HSCs toward myeloid lineage rather than lymphoid lineage. Especially, excessive COMP-Ang1 disturbed late-stage erythroblast maturation, followed by decreased expression of stromal cell-derived factor 1 (SDF-1) and globin transcription factor 1 (GATA-1) and increased levels of superoxide anion and p-p38 kinase. However, transplantation with the mutant-derived BM cells or treatment with rhCOMP-Ang1 protein did not alter the frequency or GATA-1 expression of erythroblasts in recipient mice or in cultured BM cells. Together, our findings suggest that excessive COMP-Ang1 impairs the functions of BM HSCs and MSCs and hematopoietic processes, eventually leading to abnormal erythropoiesis via imbalanced SDF-1/CXCR4 axis and GATA-1 expression rather than Ang1/Tie2 signaling axis alterations.
Lee, Won-Cheol,Chae, Min-Kyun,Soh, Kyoung-Jae,Seo, Ensung,Sohn, Young-Soo,Park, Kwangil,Kim, Byungsub,Sim, Jae-Yoon,Park, Hong-June IEEE 2019 IEEE transactions on components, packaging, and ma Vol.9 No.2
<P>A parallel branching synchronous dynamic random access memory (SDRAM) channel with write-direction impedance matching (parallel branching with write-direction impedance matching (PBIM)) is proposed for an 8-drop 6.4-Gb/s SDRAM interface. The 8-drop PBIM channel consists of two parallel branches; each branch consists of a series connection of two dual in-line memory modules for a 4-drop configuration and the data (data pin) channel uses two kinds of transmission lines with characteristic impedances of 50 and <TEX>$25~\Omega $</TEX> and a resistor on the motherboard. Measurements on the test setup show that the proposed 8-drop channel works at the DDR5 target data rate of 6.4 Gb/s in both write and read directions by using the same motherboard area as that of the stub series terminated logic channel and a bit-error-rate tester for transmitter and receiver.</P>
양원호 ( Won Ho Yang ),김치년 ( Chi Nyon Kim ),김태형 ( Tae Hyeung Kim ),노영만 ( Young Man Roh ),심상효 ( Sang Hyo Sim ),원정일 ( Jung Il Won ),이채관 ( Chae Kwan Lee ),정광호 ( Kwang Ho Chung ),정지연 ( Jee Yeon Jeong ),조기홍 ( 한국산업위생학회 2013 한국산업보건학회지 Vol.23 No.2
Objectives: This study was performed in order to investigate by questionnaire the factors affecting the occupational satisfaction of work-environment measurement workers, as well as to suggest fundamental materials for systematic, administrative and economic improvements which are necessary to create a vision for the future. Material and Methods: A structured questionnaire was used at a total of 152 institutions and 1,254 work-environment measurement workers throughout the country from February to September 2012. Responses came from 97 institutions (64%) and 941 work-environment measurement workers (75.1%). The factors affecting the job satisfaction of work-environment measurement workers were statistically evaluated through χ 2 -test and ordinal logistic regression analysis. Results: Major factors affecting the job satisfaction of workers in relation to work-environment measurement were working, financial, and psychological conditions (p<0.05). Conclusions: Considering the results of this study, the improvement of labor conditions should be undertaken because workers engaged in work-environment measurement are fundamental to occupational health.