예측전류제어기를 이용한 3상 PWM 컨버터

한홍일,함년근,성낙규,이승환,이훈구,오봉환,한경희 명지대학교 산업기술연구소 2001 産業技術硏究所論文集 Vol.20 No.-

PWM converter has better power factor and low harmonic components than conventional diode rectifiers and phase controlled rectifier. Also the DC link voltage can be regulated fast and stable against the variation in the load. In order to regulate for DC link voltage, rapid current control is need for source current control. This paper focuses on the improvement of quickness of current controller to know the transient state characteristics of regulated DC link voltage against the variation in the load. To do this, it is adopted to three phase voltage type PWM converter with space vector pulse width modulation(SVPWM) method and synchronously rotating d, q axis current. Each d, q axis current is controlled independently. To control d, q axis current, Current control methods to be applied in system are PI current control and Predictive current control respectively. As a result, Transient response characteristic of Predictive current controller is superior to PI current controller.

퍼지알고리즘를 이용한 유도전동기 속도제어에 관한 연구

조정민,전기영,함년근,이승환,이훈구,한경희 명지대학교 대학원 1999 대학원논문집 Vol.3 No.-

The conventional PI controller are fragile in parameter variation and load-variation. Therefore, in this paper, a speed control algorithm based on the Fuzzy PI controller is proposed for the high performance speed control of a voltage ?? inverter to drive 3-phase induction motors. The computer simulation and experiment results show that the proposed controller are more excellent control characteristics than conventional PI controller in transient-state and steady-state response.

미꾸라지 발현백터의 활성도 조사

함경훈(Kyung-Hoon Hahm),임학섭(Hak-Seob Lim),황지연(Jee-Youn Hwang),박진영(Jin-Young Park),김무상(Moo-Sang Kim),이형호(Hyung-Ho Lee) 한국수산과학회 양식분과 1998 韓國養殖學會誌 Vol.11 No.4

Poster Session 3 / N-10 : Structural studies of cecropin A(1-8)-magainin 2(1-12) , cecropin A(1-8)-melittin(1-12) hybrid peptides and their analogues in DPC micelles using NMR spectroscopy

(Dong Hoon Oh),(Song Yub Shin),(Joo Hyun Kang),(Kyung Soo Hahm),(Kil Lyong Kim),(Yang Mee Kim) 생화학분자생물학회 1999 생화학분자생물학회 춘계학술발표논문집 Vol.- No.-

N/A

위선암과 병발한 원발성 위 소세포암

박경남,정성훈,이규택,이동후,함준수,이종철,박문향,홍은경,양석철,기춘석,공구 대한내과학회 1990 대한내과학회지 Vol.39 No.5

Primary small cell carcinoma of the stomach has been recognized recently, and only seven well documented examples of this tumor have been reported in the English literature. This tumor is morphologically analogous to its more common pulmonary counterpart and characterized by a very aggressive clinical course. We report a case of concurrent occurrence of adenocarcinoma and primary small cell carcinoma in the stomach, which had a hepatic metastasis of small cell carcinoma. This tumor recealed a positive Grimelius stain, and the patient died 9 weeks after diagnosis. This is the first case of primary small cell carcinoma of the stomach in Korea.

상부위장관을 침범한 H-S Purpura 1예

박경남,김지훈,이민호,기춘석,함준수,이종철,박문향,이옥찬,강경원,이동후 대한소화기내시경학회 1992 Clinical Endoscopy Vol.12 No.2

Henoch-Schonlein purpura(anaphylactoid purpura) is a necrotizing vasculitis of small vessels in which systemic manifestation include palpable purpura on the lower extremities and buttocks due to leukocytoclastic vasculitis of dermal vessels; arthralgia of large joints, usually the knees and ankles; gastronitestinal involvement with colic and bleeding; and renal ievolvement, usually with a focal necrotizing glomerulonephritis. Gastrointestinal involvement occurs in about two thirds of all pediatric cases and in about,one third of adult cases, Any bowel segment may be involved, but the jejunum and ileum are most frequently affected. With a brief review of the literature, we report a case of H-S purpura involving stomach and duodenum.

결절성 갑상선질환 환자에서 일상적 혈청 칼시토닌 농도 측정의 중요성

김성훈,양태영,김동준,오은영,김광원,이문규,민용기,이명식,정재훈,정인경,함종렬,김병준 대한내분비학회 2000 Endocrinology and metabolism Vol.15 No.1

Background : Serum calcitonin is a sensitive and specific marker for diagnosis of medullary thyroid carcinoma (MTC) and its determination leads to accurate preoperative diagnosis and gives chances of definite cure. However, since many non-MTC diseases are also associated with calcitonin elevation, its significance in patients with mild or moderately elevated basal serum calcitonin levels is not clear. Furthermore, the normal value of calcitonin using immunoradiometric assay (IRMA) kit has not so far been definitely ascertained. This study is aimed at assessing the clinical significance of routine measurement of serum basal calcitonin concentration in nodular thyroid disease patients and evaluating the pentagastrin stimulation test in case of mild or moderate elevation of basal calcitonin level. We also measured serum calcitonin value in 408 normal individuals. Methods : The basal serum calcitonin concentrations using a commercial IRMA kit (Medgenix CT-U.S.-IRMA) were measured in 818 patients with nodular thyroid disease (average age 45 years with a range from 13 to 82 years; 125 males and 693 females) who visited thyroid clinics in Samsung Medical Center between June 1997 and December 1998. Serum concentrations of T3, T4, TSH and thyroid autoantibodies were measured and ultrasonography of thyroid and thyroid scan using 131I or 99mTc-pertechnetate were performed in all patients. We also studied 408 healthy subjects without any thyroid disease (average age 48 years with a range from 20 to 86 years; 224 females). Results : The calcitonin value in normal subjects was found to range from 0 to 13 pg/mL, and it was shown that men had higher calcitonin level than women(p $lt; 0.05). The rate of serum calcitonin elevation($gt; 10pg/mL) in nodular thyroid disease was 1.71%(14/818), and the incidence of MTC was 0.73% (6/818) in this study. MTC was found in all patients with basal serum calcitonin levels more than 100 pg/mL. Pentagastrin stimulation test was also required to diagnose MTC in patients with basal serum calcitonin levels between 30 and 100pg/mL. The calcitonin concentration stimulated by pentagastrin increased more than 400pg/mL or more than 3.8 times of basal concentration. It was possible to diagnose MTC with fine needle aspiration and cytology in only one case out of six patients with MTC. Conclusion : Fine needle aspiration and cytology in diagnosing MTC was not sensitive and not devoid of false positive results. We confirmed that serum calcitonin measurement was very useful means for the preoperative diagnosis of unsuspected MTC. Pentagastrin stimulation test may be a reliable means of evaluation in nodular thyroid disease patients with mild or moderate elevation of basal calcitonin level. We recommend routine measurement of serum calcitonin concentration in patients with nodular thyroid disease(J Kor Soc Endocrinol 15:70-84, 2000).

개의 췌도분리에서 췌장의 팽창과 콜라겐 분해요소

이상훈,김성주,박정환,김종성,오승훈,한진수,정인경,양태영,김동준,김광원,이문규,민용기,이명식,정재훈,함종렬 대한당뇨병학회 2000 Diabetes and Metabolism Journal Vol.24 No.2

Backgrounds: One of the main problems conditioning the outcome of islet transplantation is the ability to separate a sufficient number of viable islets with preserved function. Islet purification is critically affected by all of the isolation stages. Thus, it is necessary to set up the standard isolation method that islets are separate well from acinar without compromising islet yield and viability. Methods: Twenty three adult mongrel dogs were used for the experiment of total pancreatectomy with islet isolation. The islets were properly isolated by a modified Recordi method. The obtained islets were further purified by centrifugation on discontinuous gradients using cell separation system (Model 2991, Cobe, Lakewood Colo). We evaluated islet number (islet equivalent number, 150 um equivalents/kg of recipient body weight, IEq/kg), purity, cell volume, viabilty, recovery rate, and comparison of outcome according to the isolation conditions. Results: 1) The mean of islet numbers before purification were 13543±9431Eq/kg, digestion times were 13.8±2.6 min., digestion temperature was 37.4±0.2℃, purity was 59.7?.0%, viability was 90.0±2.1%, cell volume was 4.7±1.1 mL, islet number after purification were 4064±361 IEq/kg, and recovery rate was 29±2.9%. 2) Isolated islet numbers were different according to the degree of pancreas distension with collagenase, digestion temperature, and digestion time. 3) The best conditions for islet isolation were above 37.5℃ in temperature at recirculation of collagenase, within 12 min in digestion time and well distended pancreas with collagenase. 4) According to multiple regression adjusted by variable factors, the degree of pancreas distension with collagenase and digestion time were independently associated factors for successful islet isolation. Conclusions: In this study, we concluded that the degree of pancreas distension with collagenase and digestion time were independent factors for successful islet isolation and the best conditions for islet isolation were above 37.5℃ in temperature at recirculation of collagenase, within 12 min in digestion time and well distended pancreas with collagenase.

위장관 ( 胃腸管 ) : 위암 환자에 있어서 말초혈액 단핵구 및 국소 림프절 단핵구의 NK 및 LAK 활성도에 관한 연구

강진경(Jin Kyung Kang),최흥재(Heung Jai Choi),박인서(In Suh Park),김원호(Won Ho Kim),노성훈(Sung Hoon Noh),함기백(Ki Baik Hahm),김태수(Tae Soo Kim),안신기(Shin Ki Ahn),윤정구(Jung Koo Youn) 대한소화기학회 1991 대한소화기학회지 Vol.23 No.2

N/A Several lymphocytic subpopulations, such as natural killer (NK) cells and lymphokine-activated killer (LAK) cells, are involved in immunosurveillance against tumors. Whereas the biological significance of the regional lymph node as a tumoral barrier remains unclear, the clinical prognostic relevance of the neoplastic infiltration of these nodes is accepted. Although there is general agreement that the NK and LAK activities of peripheral blood mononuclear cells (PBMC) decreases in patients with various solid and leukemic tumors, this decrease remains unclear with regard to the NK and LAK activities of their regional lymph node mononuclear cells (LNMC). We measured NK and LAK activities of PBMC and LNMC in 10 patients with resectable gastric cancer by 4 hour Cr-release assay using K562, Raji cell and allogenous gastric cancer cell as a target cell. The results obtained are as follows: l) Recombinant interleukin-2 induced strong cytotoxic activities against various target cells in PBMC and LNMC. 2) In patients with gastric cancer, NK and LAK activities of LNMC against K56Z and Raji cell were lower than those of PBMC. 3) However, NK ad LAK activities against the allogenous gastric cancer cell did not differ between LNMC and PBMC. 4) NK and LAK activities of PBMC and LNMC against K562 and Raji cell were not different betveen in patient with early gastric cancer and in patients with advanced gastric cancer. 5) However, NK and LAK activities of PBMC ad LNMC against the allogenous gastric cancer cell were lower in patients with advanced gastric cancer than in patients with early gastric cancer.

개의 췌장소도 자가이식 결과에 영향을 미치는 인자들

이상훈,김성주,김병준,오승훈,정인경,양태영,김동준,김광원,이문규,민용기,이명식,정재훈,안규정,함종렬 대한당뇨병학회 2000 Diabetes and Metabolism Journal Vol.24 No.2

Background: Islet cell transplantation is an attractive alternative to whole organ pancreas transplantation, since it is clearly safer and simpler surgical procedure for the recipients. However, several obstacles still remain, because the free islets appear to be more susceptible to non-specific inflammatory damage or immune mediated destruction than islets in an intact pancreas. Therefore, the purpose of this study is to examine the functional outcome of islet autograff and the factors related to the islets graft survival in mongrel dogs. Methods: Twelve adult mongrel dogs weighting 12∼16 kg were used for the experiment of total pancreatectomy and islet autotransplantation. The islets were properly isolated by a modified Recordi method. The obtained islets were further purified by centrifugation on discontinuous gradients using cell separation system (Model 2991, Cobe, Lakewood Colo). After the heparization (50 U/kg), the islets were injected slowly into the liver through the portal vein for 30 minutes. The post-transplantation intravenous glucose tolerence test (IVGTn with glucose disappearance rate (K), liver function test (LFT), fasting plasma glucose (FPG) were measured periodically. Results: 1) The median of Ks were 1.3%min (range 0.3∼2.1) and the IEq/kg (150 m equivalents/kg of recipient body weight) was 3520 (range 1350∼6550). The Ks in recipients with high IEq/kg (≥5,000) were significantly higher than those in recipients with low IEq/kg ($lt;5,000)(r=0.78, p$lt;0.05). 2) The islet cell viability were estimated to be 95% and the median of the required insulin dosage for the maintenance of normal FPG were 0.7 (range 0∼1.6) U/kg/day. The insulin requirement correlated well with the level of IEq/kg (r=0.90, p$lt;0.01). 3) The median of the volume of the transplanted pancreatic islet cell were 2.1 mL (range 0.7∼5.0) and the purity was 60% (range 10∼95). The portal pressure gradients of during the transplant procedure were 4.0 (range 0.5∼12.0) cmH2O. The portal pressure gradients in recipients with high purity were significantly lower than those in recipients with low purity (r=-0.80, p$lt;0.05). Conclusions: In this study, we confirmed that autotransplantation of islet cell on the pancreatectomized dogs can render nearly normogiycemia, and transplanted islet mass was most critical factor to successful autotransplantation in canine model.