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Clinical Effects of Hypertension on the Mortality of Patients with Acute Myocardial Infarction
강동구,정명호,안영근,채성철,허승호,홍택종,김영조,성인환,채제건,류재영,채인호,조명찬,배장호,나승운,김종진,장양수,승기배,박승정,윤정한 대한의학회 2009 Journal of Korean medical science Vol.24 No.5
The incidence of ischemic heart disease has been increased rapidly in Korea. However, the clinical effects of antecedent hypertension on acute myocardial infarction have not been identified. We assessed the relationship between antecedent hypertension and clinical outcomes in 7,784 patients with acute myocardial infarction in the Korea Acute Myocardial Infarction Registry during one-year follow-up. Diabetes mellitus, hyperlipidemia, cerebrovascular disease, heart failure, and peripheral artery disease were more prevalent in hypertensives (n=3,775) than nonhypertensives (n=4,009). During hospitalization, hypertensive patients suffered from acute renal failure, shock, and cerebrovascular event more frequently than in nonhypertensives. During follow-up of one-year, the incidence of major adverse cardiac events was higher in hypertensives. In multi-variate adjustment, old age, Killip class ≥III, left ventricular ejection fraction <45%, systolic blood pressure <90 ㎜Hg on admission, post procedural TIMI flow grade ≤2, female sex, and history of hypertension were independent predictors for in-hospital mortality. However antecedent hypertension was not significantly associated with one-year mortality. Hypertension at the time of acute myocardial infarction is associated with an increased rate of in-hospital mortality.
강동구,김재한,이치영 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.12
The use of surfactant has been known as one of effective ways to improve the boiling heat transfer. However, the most of boiling research using the surfactant has focused on the nucleate boiling regime, and the surfactant effect on the MFB (minimum film boiling) point, identified with MFBT (minimum film boiling temperature) and MHF (minimum heat flux) has rarely been studied. In the present study, the effects of surfactant and liquid subcooling on MFB point of vertical stainless steel cylinder were investigated experimentally using the quenching method. As the test fluids, the aqueous SDS (sodium dodecyl sulfate) solutions (1000 wppm and 2000 wppm), known to enhance the nucleate boiling heat transfer, were tested with pure water, where their liquid subcoolings covered from 0 °C to 39 °C. Based on the present experimental data, it was revealed that the SDS surfactant can impede the MFB point, while the increase of liquid subcooling leads to accelerating the MFB point. In addition, the influence of contact angle on MFB point was examined and discussed in detail. It was found that it could be insufficient and limited to explain the general trends of MFB point using contact angle alone and the fundamental factors responsible for changing the contact angle and thermal-hydraulic conditions should be considered.
강동구,현재민 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.2
A numerical investigation was carried out for natural convection of air (paramagnetic fluid) in a cubic enclosure subjected to constant gravity and time-periodic magnetizing force. Since the magnetizing force expressed as the gradient of magnetic induction squared in each direction, has three-dimensional characteristics, three-dimensional modeling of system would be required to investigate the effect of magnetizing force more accurately. In this study as a sequent research, the basic analysis of Kang and Hyun [16] was extended to the case of three-dimensional and to cases when the magnitude of magnetizing force is varied. Two geometrical configurations for the location of electrical coils, were considered. The amplification characteristics of heat transfer rate in the cube according to the change of the magnitude of magnetizing force, were investigated especially when the resonance occurs. The numerical results showed that the heat transfer is enhanced appreciably by application of large magnitude of magnetizing force. In addition, the results for two- and threedimensional cases were also compared.