• Wind and Structures
• /
• 제30권2호
• /
• pp.133-140
• /
• 2020

In this paper, critical fluid velocity and frequency of laminated pipe conveying fluid are presented. Each layer of the pipe is reinforced by functionally graded carbon nanotubes (FG-CNTs). The internal fluid is assumed turbulent and the induced forces are calculated by momentum equations. The pipe is resting on viscoelastic foundation with spring, shear and damping constants. The motion equations are derived based on classical shell theory and energy method. Differential quadrature method (DQM) is used for solution and obtaining the critical fluid velocity. The effects of volume percent and distribution of CNT, boundary condition, lamina layer number, length to radius ration of pipe, viscoelastic medium and fluid velocity are shown on the critical fluid velocity. Results show that with increasing the lamina layer number, the critical fluid velocity increases.

• 한국응용과학기술학회지
• /
• 제20권1호
• /
• pp.51-56
• /
• 2003

Garlic extract using super-critical carbon dioxide is influenced by temperature and pressure, and the optimum condition can make under super-critical state. We can know the defects in process of super-critical extration, It can indicate the drop of product rate, energy loss and equipment expense etcs. The minimum inhibition concentration of microbe which garlic extract contains has apperared the concentration more than 800ppm in this experiment. According to the result of this experiment, we can know that the antibiosis effect in the microbe of staphylococcus and fungus has disappeared in the incubation time more than 12 hours.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1994년도 추계학술대회 논문집
• /
• pp.80-94
• /
• 1994

As for axisymmetirc sheet metal forming, a kind of pick-up apparatus for body-wrinkling is deviced. Experiments with both hemispherical and flat headed punches, with various clearances between punch and die, with respect to three kinds of materials each of which has two thicknesses, are performed. Firstly the process of evolution of body-wrinkling is observed. Then the critical blank-holding force (or meridional tensile force) for suppression of body-wrinkling at a specified punch-stroke is measured for all cases mentioned above. An empirical formula for it is proposed. Deformation patterns and stress distributions are analysed by the use of FEM. A simplified critical condition for body-wrinkling is formulated and introduced into the FEM program. And its effectiveness is checked by comparison with the experimental results. Using this FEM system, the governing factors of body-wrinkling are cleared up.

• Annals of Clinical Neurophysiology
• /
• 제22권2호
• /
• pp.61-66
• /
• 2020

Critical illness neuromyopathy (CINM) is a common but frequently underdiagnosed condition in critically ill patients that contributes to ventilator weaning failure and limb weakness in intensive care unit (ICU). CINM is subdivided into critical illness polyneuropathy and critical illness myopathy, and the occurrence of these conditions in the ICU is associated with multiple organ failure due to sepsis or certain medications. CINM survivors might have persistent functional disabilities and a poor quality of life. This situation demonstrates the need for efforts to minimize or prevent CINM in critically ill patients. This article provides a current overview of CINM and the associated clinical strategies.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1998년도 추계학술발표회요약집
• /
• pp.124-124
• /
• 1998

• 한국농공학회논문집
• /
• 제51권5호
• /
• pp.69-78
• /
• 2009

In order to improve water quality of upper watershed of Paldang reservoir, it is necessary to evaluate non-point source pollution loads and identify critical watershed pollution sources. A GIS based Soil and Water Assessment Tool was applied to evaluate model application and reliability, estimate NPS pollution load, identify critical watershed by NPS pollution sources, and suggest various best management practices for Kyongan Stream watershed. Yearly NPS pollution loads were estimated 30.0% SS, 60.1% TN and 35.4% TP, respectably. The watershed pollution load is mainly decided by precipitation condition and SS and nutrients load have a significant regression relationship. Based on 10-year average yearly NPS pollution load, critical sub-watersheds were identified. The No. 5 and 17 which have lots of relatively intensive agricultural fields and scattered industrial area were vary critical sub-watersheds and under more intensive pollution load. In order to control critical watershed, watershed best management practices such as scientific fertilizer, contour farming and parallel terrace, transferring the sloppy farmland to grass or forest and constructing a buffer zone, and constructing wetlands and retention ponds will be applied. Overall the SWAT model can be efficiently used for identification of critical sub-watersheds in order to develop a priority watershed management plan to reduce water pollutions.

• Clinical and Experimental Pediatrics
• /
• 제56권12호
• /
• pp.519-522
• /
• 2013

Timely diagnosis of hyponatremia is important for preventing potential morbidity and mortality as it is often an indicator of underlying disease. The most common cause of eurvolemic hyponatremia is the syndrome of inappropriate antidiuretic hormone (SIADH) secretion. Recent studies have demonstrated that proinflammatory cytokines such as interleukin (IL) $1{\beta}$ and IL-6 are involved in the development of hyponatremia, a condition that is associated with severe inflammation and is related to antidiuretic hormone (ADH) secretion. Serum sodium levels in hyponatremia are inversely correlated with the percentage of neutrophils, C-reactive protein, and N-terminal-pro brain type natriuretic peptide. Additionally, elevated levels of serum IL-6 and IL-$1{\beta}$ are found in inflammatory diseases, and their levels are higher in patients with hyponatremia. Because it is significantly correlated with the degree of inflammation in children, hyponatremia could be used as a diagnostic marker of pediatric inflammatory diseases. Based on available evidence, we hypothesize that hyponatremia may be associated with inflammatory diseases in general. Understanding the mechanisms responsible for augmented ADH secretion during inflammation, monitoring patient sodium levels, and selecting the appropriate intravenous fluid treatment are important components that may lower the morbidity and mortality of patients in a critical condition.

• Progress in Superconductivity
• /
• 제6권2호
• /
• pp.138-141
• /
• 2005

Bi-2223/Ag tapes need to be safe, even it is under the over-critical current state for the protection of a superconducting power machine. However, it is not easy to identify the condition for the safe operation because of their broad S/N transition region. In this paper, for the study of the operation condition of Bi-2223/ Ag tapes, we investigated the V-I curves and the temperature variation of Bi-2223/ Ag tapes experimentally, applying alternating over-currents, and analyzed the relationship between resistance and temperature increase. For the experiments, a Bi-2223/Ag tape of 57 A $I_c$ was prepared, and the over-critical current characteristics under adiabatic state from $LN_2$ was measured. From the experiments, we confirmed that the Joule heating predicted by V-I curve corresponded with the increase of the measured temperature exactly. Using the results, a safe operation condition of Bi-2223 tape was discussed.

• 중환자간호학회지
• /
• 제11권1호
• /
• pp.79-88
• /
• 2018

Purpose : This study was performed to evaluate the effects of a prolonged a $30^{\circ}$ side-lying position on comfort and skin condition by applying the trunk maintenance repositioning method, which can keep the $30^{\circ}$ side-lying position effective for preventing pressure ulcers. Method : Fifty-four healthy nurses working at a general hospital in Seoul were randomly assigned to an experimental group (n=27) or a control group (n=27) and assumed a position of lying on their right or left side for two hours. The trunk maintenance repositioning method was applied to the experimental group using the pillow made by the researcher, while the original repositioning method was applied to the control group using the regular pillow from the subject hospital. Participants' posture angles, comfort, and skin condition were measured at the time of the intervention, as well as at one and two hours after the intervention. Results : There was no statistically significant difference in position angle, comfort, skin condition change, or sacrum and greater trochanter pressure change between the two groups over time. Conclusion : It is necessary to review the method and frequency of change of position in each hospital. In addition, a proper position changing pillow should be developed in consideration of patients' various body shapes.

• 전자공학회논문지
• /
• 제50권8호
• /
• pp.151-161
• /
• 2013

본 논문에서는 입력전압을 감지하지 않는 전류연속/임계동작모드 active power factor correction(PFC) circuit을 제안하였다. 기존의 입력전압을 감지하지 않는 PFC circuit의 경우 출력전류가 낮은 경 부하 조건에서 DCM 동작을 수행하고, 이에 따라 PF가 감소하는 문제가 발생한다. 제안한 PFC circuit은 70KHz의 주파수로 CCM 동작을 수행하고, 경 부하 조건에서 최대 200KHz까지 스위칭 주파수가 가변되는 CRM 동작을 수행하도록 하였다. 이를 통해 경 부하 조건에서 PF가 감소하는 문제를 해결하였다. PFC controller IC는 $0.35{\mu}m$ BCDMOS 공정을 이용하여 제작하였으며, 240W급 PFC prototype을 제작하여 실험하였다. 제안한 PFC circuit은 기존의 PFC circcuit 대비 최대 10%의 역률이 향상되었고, IEC 61000-3-2 Class D 규격에 따른 경 부하 조건에서는 최대 4% 역률이 향상되었다.