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EDLC와 Backup power controller를 이용한 PLC 데이터 백업 시스템 구현
김석연(Seok-Yeon Kim),남제우(Jae-Woo Nam),강지웅(Ji-Woong Kang) 대한전자공학회 2021 대한전자공학회 학술대회 Vol.2021 No.6
In general, industrial control devices, including PLCs, the data need to be maintained for subsequent work that changes from time to time such as production history or status of production facilities even if when it is turned off. PLC is an equipment that can be programmed according to the user"s needs, and as the industrial environment becomes increasingly complex and high-speed, a situation where a larger amount of data backup is required may occur. Memory for data backup includes Flash-based memory, MRAM, FRAM, etc., which are nonvolatile memory, and battery backup SRAM is also widely used. However, since Flash-based memory takes a long time to read/write data, it is difficult to access it from time to time. In addition, MRAM, FRAM, and SRAM are expensive and occupy a lot of space on the PCB because they have low density compared to memory capacity. To solve this problem, a method was implemented that operation data for backup is in DRAM during operation and transfer it to the Flash-based memory when the power is turned off. After the power is turned off, it is necessary to maintain the power for a period of time to transfer the DRAM data to the flash-based memory. To this end, the EDLC(Electric double layer capacitor) and LTC3351[1], a backup power controller of Analog Device, are used.
한국인에서의 Paraoxonase Gene Polymorphism 과 관동맥 질환과의 관계
유경훈(Kyong Hoon You),김석연(Seok Yeon Kim),김효수(Hyo Soo Kim),손대원(Dae Won Sohn),오병희(Byung Hee Oh),이명묵(Myoung Mook Lee),박영배(Young Bae Park),최윤식(Yun Shik Choi),이영우(Young Woo Lee) 대한내과학회 1998 대한내과학회지 Vol.55 No.6
N/A Objectives: Paraoxonase is a high density lipoprotein (HDL)-associated enzyme, which has been implicated in preventing low density lipoprotein-cholesterol (LDL-C) from oxidation. The human paraoxonase gene is codominantly expressed as allele A and B. The A allele codes for glutamine(A subtype) and the B allele for arginine(B subtype) at codon 192 of the paraoxonase enzyme. This genetic polymorphism divides the enzyme into high and low activity form It has been believed that this difference of specific activity might change the metabolism of cholesterol and the prevalence of coronary artery disease. The present study investigated the association among the paraoxonase gene polymorphism and the level of plasma lipoprotein and coronary artery disease. Methods: The 416 subjects who have undergone coronary angiography in SNUH were recruited. 7he patients(n=251) had >50% stenosis of at least one of the major coronary arteries. To identify the genotype of paraoxonase, we amplified the target region in the paraoxonase gene by PCR(polymerase chain reaction) and electrophoresed the products. Results: There was no difference between the two groups in the allele frequency (A: B = 0.41: 0.59 in patients, A: B = 0.37: 0.63 in controls; p=0.21) or in the genotype frequency (AA:AB:HB= 45:116:90 in patients, AA:AB:BB=22:77:66 in controls; p=0.41). There was no association of the paraoxonase genotype with serum lipoprotein level and acute coronary syndrome in this study. The B allele was not an independent risk factor for coronary artery disease in this study. Conclusion: The paraoxonase gene 192 polymorphism was not an independent risk factor for coronary artery disease in this study.
1 kW급 스털링엔진 고온 열교환기의 Fin 형상 개선 효과 분석
안준(Joon Ahn),김석연(Seok Yeon Kim) 대한기계학회 2017 大韓機械學會論文集B Vol.41 No.8
본 연구에서는 1 kW급 가정용 열병합 시스템의 원동기로 설계된 스털링 엔진의 고온 열교환기에 대하여 Fin 길이, 간격, 각도 등을 조정한 새로운 형상 및 기존 형상에 대하여 수치해석을 수행하여 형상 개선에 따른 성능 향상을 확인하였다. 형상을 개선하는 과정에서 고려하지 않았던 공기예열기를 포함하여 수치해석을 수행한 결과 실린더 헤드 부분에서 음의 열유속이 발생하는 현상이 관찰되었다. 배가스 온도 및 연소실 벽면 온도를 분석하여 이 현상을 규명하였다. 다음으로 이상적인 사이클을 가정하여 형상 개선에 의한 열전달량 증가가 열역학적 사이클 및 시스템 성능에 미치는 영향을 예측하였다. In this research, numerical analysis was carried out on novel and existing fins, adjusted in terms of factors such as length, spacing, and angle, of a high-temperature heat exchanger for a 1 kW class Stirling engine, designed as a prime mover for a domestic cogeneration system. The performance improvement as a result of shape optimization was confirmed with numerical analysis by including the air preheater, which was not considered during optimization. However, a negative heat flux was observed in the cylinder head portion. This phenomenon was clarified by analyzing the exhaust gas and wall surface temperature of the combustion chamber. Furthermore, assuming an ideal cycle, the effects of heat transfer enhancement on the thermodynamic cycle and system performance were predicted.
고콜레스테롤혈증 치료에서 심바스타틴 10mg 과 20mg 사용시의 효능 및 안전성 비교 연구
이재건(Jae Gun Lee),김화민(Hwa Min Kim),이현희(Hyun Hee Lee),최혜진(Hae Jin Choi),박창하(Chang Ha Park),서명덕(Myung Deok Seo),정재천(Jae Cheon Jeong),조한균(Han Kyun Cho),최성식(Sung Sik Choi),이지현(Ji Hyun Lee),김석연(Seok Yeon Ki 대한내과학회 2002 대한내과학회지 Vol.63 No.1
목적 : 지방공사 강남병원 순환기 내과에서 추적 검사 받는 고지혈증 환자 106명을 대상으로, 심바스타틴 상용량인 10 mg과 20 mg 사용시의 콜레스테롤 저하 효과, 부작용 등에 대해 조사하였다. 방법 : NCEP guideline에 따라 약물 치료가 필요한 환자 중 저비중 지단백 콜레스테롤 농도가 130 mg/dL 이상이면서 중성 지방 농도는 400 mg/dL 이하인 고콜레스테롤혈증 환자를 대상으로 심바스타틴 사용량을 10 mg 군과 20 mg 군으로 무작위적으로 나누어 처방한 후 6개월 후의 혈중 지질 농도를 분석하였다. 환자들은 매월 부작용 여부를 확인하기 위해 정기적 외래 검진을 받았으며 심각한 부작용이 나타나거나 합병증이 나타난 경우 치료 대상에서 제외하였다. 1997년 4월부터 2000년 11월까지의 115명 중 탈락되지 않은 106명의 결과를 분석하였다. 결과: 남녀비는 40:66이었고, 전체 대상군 중 55%에서 고혈압이 있었고, 9%에서 관상동맥 질환이 있었으며, 13%에서 당뇨병이 존재하였다. 심바스타틴 투여 전 평균 지질 농도는 258-201-50-167 (총 콜레스테롤-TG- HDL-LDL)이었다. 저비중 지단백 콜레스테롤 농도는 20 mg 군에서 34.9 mg/dL, 10 mg 군에서는 20.8 mg/dL 감소하였고, 20 mg 군이 10 mg 군에 비해 저비중 지단백 콜레스테롤 농도를 의미 있게 더 감소시켰다. 총 콜레스테롤 농도는 20 mg 군에서 22.7 mg/dL, 10 mg 군에서 21.7 mg/dL 감소하였고, 심바스타틴 복용 용량에 따른 감소 효과의 차이는 없었다. 심바스타틴 용량에 따른 NCEP guideline (ATP III)의 저비중 지단백 콜레스테롤 목표 농도 달성 정도를 조사한 결과 관상동맥 질환의 위험 인자가 0∼1개인 저위험군에서는 20 mg 군이 80%, 10 mg 군이 81%에서 목표 농도가 되었고, 고위험군에서는 20 mg 군 50%, 10 mg 군 35%가 목표 농도에 도달하여 저위험군에 비해 치료 성공률이 낮았다. 중성 지방 농도는 10 mg 군과 20 mg 군 모두에서 의미있게 감소하지 않았으나 200 mg/dL 이상의 고중성지방군에서는 심바스타틴 20 mg 사용 군에서 22.3 mg/dL, 10 mg 군에서 42.7 mg/dL 감소하여 10 mg 사용 군에서 20 mg 사용 군에 비해 의미 있게 중성 지방을 감소시켰다. 고비중 지단백 콜레스테롤은 심바스타틴 복용 전 농도가 40 mg/dL 미만인 경우에는 20 mg 복용 군에서 11.5 mg/dL, 10 mg 복용 군에서 8.3 mg/dL가 증가하였다. 6개월간의 심바스타틴 치료를 하는 동안에 부작용 때문에 약물 복용을 중단한 경우는 전신 근육통이 심해 중단한 것 외에는 없었고, 심각한 부작용을 가진 환자는 없었다. 연구 대상 환자들에 대한 약물 용량에 대한 선호도 조사 결과 10 mg에 대한 선호도가 높았다. 결론: 심바스타틴은 고콜레스테롤혈증 한국인에서 10 mg과 20 mg 사용시 모두 지질 농도를 개선하는데 효과적이었다. 그러나 관상동맥성 심질환을 가진 고위험군에서는 NCEP guideline을 만족시키는데 효과적이지 못했다. 환자들의 선호도를 고려할 때 고위험군외에는 초기 치료 용량을 10 mg으로 시작하는 것이 좋을 것으로 보인다. Background: Elevated serum cholesterol level is a major risk factor for cardiovascular morbidity and mortality. Simvastatin is effective for treating hypercholesterolemia. The aim of the study was to evaluate efficacy and safety of 6-month therapy with simvastatin with relatively low dose, 10 mg and 20 mg/day. Methods: One hundred six patients with hyperlipidemia (triglycerides<400 mg/dL and low- density lipoprotein (LDL) cholesterol>130 mg/dL) were randomized to receive either simvastatin 10 mg/day (n=43) or 20 mg/day (n=63). Efficacy was determined by measuring changes from baseline in lipid parameters including LDL cholesterol, total cholesterol, triglycerides and high-density lipoprotein (HDL) cholesterol. Results: Of the one hundred six patients randomized to treatment, forty patients were men and sixty-six patients were women. Fifty-five percent of patients had hypertension, nine percent coronary artery disease and thirteen percent type 2 diabetes mellitus. Mean baseline lipid concentrations were 258 (total cholesterol), 201 (triglycerides), 50 (HDL) and 167 mg/dL (LDL). Both 10 mg and 20 mg of simvastatin produced statistically significant improvements in all measured serum lipid parameters (p<0.001). Compared with 10 mg of simvastatin, 20 mg of simvastatin produced significantly greater (p<0.001) reductions from baseline LDL cholesterol (34.9 mg/dL vs 20.8 mg/dL). But 10 mg of simvastatin was more effective than 20 mg of simvastatin at reducing triglycerides level (42.7 mg/dL vs 22.3 mg/dL). There was no significant difference in both doses at improving total cholesterol and HDL cholesterol level. Percentage of patients at goal LDL as recommended by NCEP guideline (ATP III) were 81% and 80% for patients in low risk but 35% and 50% for patients in coronary heart disease and its risk equivalents, taking 10 mg and 20 mg/day respectively. Both doses were well tolerated. Only 3 patients (4.8%) in the 20 mg group and one patient (2.3%) in the 10 mg group experienced mild adverse events. Most patients contacted by telephone wanted to take 10 mg of simvastatin. Conclusion: In patients with hypercholesterolemia in Korea, both doses (10 mg, 20 mg) of simvastatin were effective in improving serum lipid parameters and well-tolerated. We recommend, considering patients' preference, that 10 mg of simvastatin be intial dosage and in patients with coronary heart disease, higher doses than 20 mg should be prescribed to allow most patients to reach their NCEP target levels.(Korean J Med 63:46-53, 2002)