비용절감형 컨버터 구조를 갖는 3상-3상 PWM 정류기/인버터 시스템

박태열,김기택,이해춘 江原大學校 産業技術硏究所 1998 産業技術硏究 Vol.18 No.-

A current controlled VSI-PWM rectifier and inverter with capacitor dc link is regarded as one of the most promising structures for three-phase to three-phase to three-phase power conversion. This type of converter normally requires twelve switches for a rectifier and inverter composed of self turn-off switch such as a bi-polar transistor or IGBT with an anti-parallel diode. In this paper, a new three-phase to three-phase converter for ac motor drives is proposed. The proposed converter employs only eight switches and has the capability of delivering sinusoidal input currents with unity power factor and bidirectional power flow. This paper describes the feasibility and the operational limitations of the proposed structure. A mathematical model of the system is derived using generalized modulation theory and experimental results for steady state and dynamic behavior are presented to verify the developed model.

단순반복 작업자의 작업대 및 의자의 형태와 누적외상성질환 증상과의 관계

정현기,노영만,임현우,박정일,정춘화 대한산업의학회 2001 대한직업환경의학회지 Vol.13 No.2

목적 : 단순반복작업 생산직 근로자의 누적외상성질환에 대한 사업주의 건강관리규정 준수상태 및 근로자의 자각증상호소와 의자 및 작업대의 형태를 파악하고 크기를 측정하여 이들과 누적외상성질환 자각증상호소와의 관련요인을 알아보고 대책을 제공하고자 한다. 방법 : 서울 및 경기지역 일부 100인 미만 사업장중 전기, 전자부품 제조업체 7개를 선정하여 생산직 근로자 77명을 대상으로 누적외상성질환에 대한 사업주의 건강관리규정 준수상태와 및 근로자의 자각증상호소에 대한 설문조사를 실시하고 의자와 작업대의 크기를 측정하고 증상과의 관련요인을 알아보기 위하여 로지스틱회귀분석을 실시하였다. 결과 : 의자와 작업대가 작업자세에 영향을 준다고 인식하는 작업자는 85.7 %이였으며 단순반복작업 근로자 작업관리지침에 의한 사업주의 근로자에 대한 관심은 매우 낮았다. 누적외상성질환 자각증상 호소율은 63.6 %이였으며 자각증상 부위는 어깨 37.9%, 목 15.2 %, 등 6.1 %, 팔/팔꿈치 4.6 % 순이였다. 입사 후 초기발생시기는 평균 16.5개월이며 자각증상 호소는 작업대 두께, 작업대높이, 작업대 밑무릎공간, 등받이 높이, 좌석면 높이, 좌석면의 앞뒤길이, 좌석면의 좌우길이, 작업대끝에서 어깨까지의 거리에서 유의한 관련이 있었다. 자각증상호소의 관련요인은 등받이 높이, 좌석면의 높이, 좌석면의 앞뒤길이 이였다. 결 론 : 이상의 결과로 보아 정부는 단순반복작업 작업자의 누적외상성질환 예방을 위하여 사업주에 대 한 철저한 교육 및 관리감독을 해야한다. 사업주는 작업대 및 의자를 작업자의 신체치수와 작업내용에 맞게 높이를 조절할 수 있는 제품을 사용하고 작업전, 후에 정기적인 건강체조 및 휴식을 갖도록 하며 근로자에 대한 실질적인 보건교육이 이루어져야 한다. Objectives : The main purpose of this study was to investigate relationship between cumulative trauma disorders (CTDs) and the types of workstation and chair in workers with repetitive motion tasks. Methods : The study subjects were 77 repetitive motion tasks workers at small manufacturing industries in Seoul and Gyung-gi district area. A questionnaire was used to obtain about health practice for prevention and prevalence of CTDs by worker. The type of Workstations and chairs in workers were measured and analyzed with prevalence of CTDs by logistic regression. Results : Eighty-six percent of workers recognized that work posture was related to workstation and chair, Most employers and employees didn't follow the work practice guidelines for workers with repetitive motion tasks. The prevalence of CTDs was 64% by questionnaire. The prevalence of pain in shoulder, neck, back, and arm were 38%, 15%, 6%, and 5%, respectively, and the pain started after working an average duration of 16.5 months. The CTDs symptoms were significantly related to thickness of workstation, height of workstation, length of knee depth under workstation, height of back rest, height of seat pan, depth of sitting surface, width of sitting surface, and length from workstation surface edge to shoulder. By multiple regression analysis of each risk factor, prevalence of CTDs was highly correlated with height of back rest, height of seat pan, and depth of sitting surface. Conclusions : This study suggests that workstations should be made adjustable for height and chairs should be equipped with seat pan height control, enough sitting surface for depth and width, back rest height and angle control. The workers should use the right working postures, exorcise for health, occupational health education, and rest breaks and the manager of company should be educated for the preventing of CTDs.

In situ hybridization과 염색체 미세해부에 의한 특정 염색체 띠에 대한 유전자 발굴

홍기정,김현수,전용혁,김현,박선화 고려대학교 의과대학 1996 고려대 의대 잡지 Vol.33 No.1

Recently surmountable amounts of genes are being cloned but it is hard to define the chromosomal location and functions of these genes. In this study, a new technique was developed for cloning genes expressed in the developing human brain with confirmed chromosomal location. The mRNAs were extracted from 18 week old human fetal brain, cDNAs were made by reverse transcription from these mRNAs and Uni-amp cDNAs having Uni-amp adapters a t both ends were made for subsequent PCR. To observe the distribution of the Uni-amp cDNAs on the chromosome, fluorescent in situ hybridization was performed with biotin labeled Uni-amp cDNAs. Among the chromosome bands showing strong hybridization with the cDNAs, lq21, lq25, lq32 and lq42 were microdissected from the chromosome hybridized with unlabeled Uni-amp cDNAs and amplified by PCR with Uni-amp primers. These amplified cDNA fragments were subcloned to plasmid vectors and the nucleic acid sequences were analysed. As a result 18 different clones were confirmed the chromosomal localization. They were categorized as 4 clones of well characterized genes, 3 clones showing low homology with known genes, 5 clones of simply registered uncharacterized human cDNAs, and 6 clones of unknown genes. The evidence suggests that the technique is very useful to clone the genes that express in the developing human brain, with confirmed chromosomal location. In addition, this cloning technique can be used to discover the new genes related with neuronal development in combination with functional screening method.

DSP 소프트웨어에 의한 전력변환기 게이팅 신호 발생

이해춘,박태열,김기택 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.A

Power converters are widely used in the applications of servo drives of ac and dc motors and power supplies. For the control of the converters carious control algorithms hate been proposed and realized by gating signal generation. Software control shemes are being applied to implement the control algorithms, but analog circuits are still used fort the gating signal generation because it requires verb fast and precise timing. In this paper the gating signal generation with DSP software are proposed for the three phase to three phase PWM converter. Design procedures and software flowcharts are presented and some experimental waveforms are also presented to verify the proposed algorithms.

강원도 원주지역 초·중·고등학생의 식습관 및 섭식행동에 관한 단면연구

허혜경,박소미,김기연,김춘배,안정숙,송희영,김기경 韓國保健敎育.健康增進學會 2003 보건교육건강증진학회지 Vol.20 No.1

Purpose : The purpose of this study was to investigate the dietary habits of students in order to identify risk groups according to their Body Mass Index (BMI), and to compare the eating behavior of students in the normal range (19<I≤24) and those in risk groups (BMI≤19, 24<I≤27, BMI>). Method : 1176 elementary school students, 850 middle school students and 672 high school City, were the participants The instrument for this study was a structured questionnaire that included demographic data as well as dietary habits, and the eating behavior instrument developed by Stunkard &essick(1985) and revised by Kim &im (1997). Result : 1) As students moved up in grade level their dietary habits became more irregular and the degree that students chewed food was reduced 2) As students moved up in grade level, a greater number of the students did not eat breakfast. The reasons given were that there were not enough time before classes started(40.4%) and a lack of appetite in the morning(10.6%) in high school students. 3) As for supper, from 67.8 to 81.9% of subjects reported having regular supper. However the rest of the subjects did not eat supper because of anorexia and fear of weight gain. 4) The results identified risk groups according to their BMI showed that for elementary school students, 55.9% were in the low weight group, 5.5% in the overweight group, and 0.9% in the obese group. For middle and high school students, 40.6% and 35.5% respectively were in the low weight group, 7.4% and 6.3% in the overweight group, and 4.1% and 2.5% the obese group. 5) Comparisons of the eating behavior of students in the normal weight group with that of those in the three risk groups showed that there were significant differences in 'hunger' and 'cognitive restraint of eating' in elementary school students, and significant differences in 'cognitive restraint of eating' in middle and high school students. Conclusion : The results of this study show that management of diet in school health sholud be addressed from both the aspect of lack of nutrition and that of excess nutrition. In other words, good diet is as important for students in the low weight group as it is f3r those in the overweight and obese groups. The estatblishment of good dietary habits and eating behavior in students, by nurses and dieticians should be done by providing repeated diet education and involvement in diet counseling.

측두하악 관절의 재건을 위한 늑연골 이식의 효과

김태규,정기돈,신상훈,김성길,이성근,박상준,서종천 大韓顎顔面成形再建外科學會 1996 Maxillofacial Plastic Reconstructive Surgery Vol.18 No.3

We performed costochondral grafting in mmandibular reconstruction including condyle replacement in 5 patients which have 4 cases of ameloblastoma, 1 case of resorption of left condyle due to osteomyelitis. We harvested the 6 th costochondral cartilage of unaffected side. No specific complications were appeared with unexpected fracture of costochondral junction and infection of operation site, These patients show 30-45mm at month opening, near normal of affected side, near normal or normal of unaffected side at lateral excursion. Postoperative coureses was uneventful with improved cosmetic and functional results. Our report is indicated that the costochondral graft is satisfactory to reconstruct mandibular defect including condyle replacement, especially in growing patients.

비호지킨 림프종의 임상적 고찰

김태원,조은택,조기섭,정재용,허재봉,장영,박유환,정춘해 조선대학교 1995 The Medical Journal of Chosun University Vol.20 No.1

A retrospective clinical and histologic study of 30 non-Hodgkin's lymphomas diagnosed at the Department of Hemato-oncology of the Chosun University from January 1989 to December 1993 is presented. Among total 30 cases whose sexes were mentioned, male were 18 and female were 12 and the ratio is 1.5:1. The peak incidence of non-Hodgkin's lymphoma was found in the third decade. The case distributions by Working formulation were summarized in table 3. The most common histopathologic type of non-Hodgkin's lymphoma was the diffuse large cell type of intermediate grade. The presenting symptoms at the time of first visit to the hospital were summarized in table 4. The most common symptoms were palpable mass. Lymph node enlargements were found in 87 %, and most frequently on cervical area(35%). The incidence of primary nodal lymphoma is more frequent than extranodal lymphoma, 1.2:1. The most common primary site of extranodal lymphoma is the gastrointestinal tract. In the laboratory findings, the data of hemoglobin and hematocrit were summarized in table 8, 9, Values of hemoglobin and hematocrit of female patients greater than those of male patients. The results of the immunophenotypings of nodal and extranodal lymphoma indicates that the B-cell lymphoma are predominant(B:T=1.4:1). The clinical stage was Ⅱ in 9 cases(30%) Ⅲ in 9 cases(30%), Ⅳ in 8 cases(26.7%), Ⅰin 4 cases(13.3%), 28 cases were treated with CHOP regimen. Among them, 17 cases(60.8%) achieved a complete remission. 5 cases had a partial response. The most frequent toxicities were toxic hepatitis.

A comparative study on the effect of intraperitoneal anti-adhesive agent application in left liver living donors

Chun-Soo Park,Shin Hwang,Chul-Soo Ahn,Ki-Hun Kim,Deok-Bog Moon,Tae-Yong Ha,Gi-Won Song,Dong-Hwan Jung,Gil-Chun Park,Jung-Man Namgoong,Hyung-Woo Park,Yo-Han Park,Sung-Hwa Kang,Bo-Hyeon Jung,Sung-Gyu Le 한국간담췌외과학회 2013 한국간담췌외과학회 학술대회지 Vol.2013 No.4

Fitness cost and competitive ability of transgenic herbicide-tolerant rice expressing a protoporphyrinogen oxidase gene

Chun, Young Jin,Kim, Dae In,Park, Kee Woong,Jeong, Soon-Chun,Park, Sangkyu,Back, Kyoungwhan,Kim, Chang-Gi The Ecological Society of Korea 2013 Journal of Ecology and Environment Vol.36 No.1

The expression of transgenic traits in genetically modified crops is sometimes associated with decreases in crop performance or fitness. These decreases in performance or fitness of transgenic plants in unfavourable conditions may provide valuable information about the ecological consequences of transgene escape. In a glasshouse trial, we tested the cost associated with resistance to herbicides by comparing the growth, yield, and competitive ability of transgenic rice with its parental non-transgenic line. This new line was developed for constitutive overexpression of protoporphyrinogen oxidase (PPO) to increase resistance to herbicides. We evaluated nine agronomic traits of transgenic and non-transgenic rice grown in a replacement series design over four densities. Competitive ability was also assessed between transgenic and non-transgenic plants by analyzing their relative yields based on biomass and seed weight data. Our results indicated that non-transgenic plants showed greater performance than did the transgenic plants when those genotypes were grown in mixtures. The non-transgenic rice plants exhibited superior competitive ability at certain combinations of planting densities and genotype proportions. These results suggest that PPO-herbicide resistance incurs some costs in plant performance and competitive ability.

Sperm Fertility of Transgenic Boar Harboring hEPO Gene is Decreased

Park Chun-Gyu,Kim Sung-Woo,Lee Poong-Yeon,Han Joo-Hee,Lee Hyun-Gi,Byun Sung-June,Yang Boh-Suk,Lee Chang-Hyung,Lee Hoon-Taek,Chang Won-Kyong,Park Jin-Ki 한국동물생명공학회(구 한국동물번식학회) 2006 Reproductive & developmental biology Vol.30 No.1

This study was conducted to compare the reproduction ability of the wild type boar and recombinant human erythropoietin (hEPO) transgenic boar semen. Ejaculated boar semen was analyzed by flow cytometry, Elisa and IVF methods. In experiment 1, flow cytometric analysis showed that the live sperm ratio of transgenic boar sperm significantly lower (P<0.05) than that of wild type boar after incubation at 20, 22, 24 and 26 hr. In experiment 2, the presence and levels of various cytokines (IL-6, IL-10 and TNF-α) to related animal reproduction in the seminal and blood plasma were examined using specific enzyme immunoassay. There was no significant difference between both groups. In experiment 3, the fertilizing capacity and developmental ability of both boar sperm were compared. The transgenic boar sperm had a significantly low capacity of penetration, sperm-zona binding, embryo development, and blastocyst formation compared to wild type sperm (P<0.05). These results suggest that transgenic boar sperm harboring hEPO gene has low sperm viability than wild type boar, and it is a reason to decrease of fertility and litter size.