• 대한기계학회논문집B
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• 제20권9호
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• pp.2909-2915
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• 1996

Precise and accurate pressure measurements are obtained using deadweight piston gauges. Pressure distribution and elastic distortion in the piston-cylinder unit are the leading factors in determination of effective area. The distortion depends upon the pressure distribution in the clearance between piston and cylinder and those are coupled each other. Considering the viscosity pressure relation of oil and governing flow equation in the clearance, a new numerical iterative algorithm is developed. The disagreement between the monotonous and sharp pressure profiles is an indication that the pressure profile will be different for each piston and cylinder unit due to material variances.

• 대한기계학회논문집
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• 제18권9호
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• pp.2257-2264
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• 1994

A method to evaluate the position performance for a stochastically defined planar robot manipulator is presented. Performance is defined as the operational reliability based upon the positional errors of the manipulator tip. An analytical method is developed and applied to a two-link robot manipulator through forward kinematics. This study includes uncertainties in the link length, pin center location and radial clearance. By virtue of the effective link length model, only the nominal manipulator model and statistical information on the uncertainties are required. The results from the analytical method is compared to those from the Monte Carlo simulation.

• Tribology and Lubricants
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• 제10권3호
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• pp.47-53
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• 1994

Thin film flow in the clearance between cylinder bore and axially moving compositeshape piston is analyzed to study the effect of piston shape on the lubrication characteristics of hydraulic piston pump and motor. It is shown that the piston shape significantly affect the distribution of fluid film pressure, lateral force acting on the piston and leakage flow rate in the clearance. And it is also shown that the composite-shape piston is more effective than the cylindrical piston under tilted condition to reduce the possibility of hydraulic locking. Therefore, the results of present study can be used usefully in the design-and manufacturing of hydraulic piston pump and motor.

• 대한약리학회지
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• 제2권1호
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• pp.5-12
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• 1966

In this study the influence of Bradykinin, a biogenic polypeptide, on the excretory function of the dog kidney was investigated, utilizing the clearance and stop-flow method. The results are summarized as follows; 1) Bradykinin administered intravenously elicited a marked antidiuresis. 2) When given into the renal artery, however, prompt increase of the urine flow, sodium excretion and free water clearance without significant change in the glomerular filtration rate ensued. 3) It was also effective during an osmotic diuresis with 10% Mannitol infusion, though the response was not so marked. 4) The stop-flow experiment showed that sodium reabsorption in the proximal tubules is inhibited by the infusion of bradykinin into the renal artery. It was thus concluded that the diuretic effect of bradykinin given intra-arterially results from the inhibition of sodium transport in the proximal tubules.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.341-346
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• 2014

Intake E-CVVT noise, generally caused by collision sound of roller and cage clearance at idle and driving condition, is considerable source of annoyance in passenger cars using the gasoline engine. Main source of this noise is the cam torque variation of an intake E-CVVT system, and can be controlled by clearance decrease such as backlash reduction, but which may increase the manufacturing cost. Thus in this paper, most effective solution for low noise intake E-CVVT was achieved through not only reduction of backlash and cam angular acceleration but also improvement of vehicle transfer system, which is optimal configuration through acoustic sensitivity optimization of engine mount support bracket.

• Nuclear Engineering and Technology
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• 제51권6호
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• pp.1650-1657
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• 2019

Fluidelastic instability and nonlinear dynamics of tube bundles is a key issue in a steam generator. Especially, once the post-instability motion of the tube becomes larger than the clearance gap to other tubes, effective contact or impact between the tubes under consideration and the other tube inevitable. There is seldom theoretical analysis to the nonlinear dynamic characteristics of a tube array in two-phase flow. In this paper, experimental and numerical studies were utilized to obtain the critical velocity of the flow-induced instability of a rotated triangular tube array. The calculation results agreed well with the experimental data. To explore the post-instability dynamics of the tube array system, a Runge-Kutta scheme was used to solve the nonlinear governing equations of tube motion. The numerical results indicated that, when the flow pitch velocity is larger than the critical velocity, the tube array system is undergoing a limit cycle motion, and the dynamic characteristics of the tube array are almost similar for different void fractions.

• 방사성폐기물학회지
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• 제2권1호
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• pp.60-67
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• 2004

연구로 1,2호기 해체과정에서 발생되는 많은 양의 철재폐기물 중 자체처분대상 철재폐기물을 대상으로 재활용하는 경우에 대해서 피폭방사선량을 평가하고, 규제해제농도기준(안)을 도출하였다. 평가도구는 RESRAD-RECYCLE ver 3.06을 이용하여 ICRP60에서 제시하고 있는 유효선량 개념에 근거한 내부피폭 선량환산인자를 수정하였고, IAEA Safety Series 111-P-1.1 및 NUREG-1640을 적용하여 예상되는 최대개인선량 및 집단선량을 평가하였다. 0.4 Bq/g의 철재폐기물에 대한 RESRAD-RECYCLE 전산코드의 평가결과 개인최대선량 및 집단선량은 23.9 $\mu$Sv/y, 0.11 man$.$Sv/y이다. 최종적인 핵종별 규제해제농도기준은 일반평가방법과 세부평가결과를 종합하여 가장 보수적인 평가결과를 추출하여 결정하였다. 그 결과 $Co^{60}$, C $s^{137}$ 핵종에 대한 규제해제농도준위는 1.14${\times}$$10^{-1}$ Bq/g미만이 되어야 국내 원자력법에서 정하고 있는 처분제한치(최대개인선량 : 10 $\mu$Sv/y, 집단선량 : 1 man$.$Sv/y)를 만족할 수 있다.

• 대한한방부인과학회지
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• 제33권2호
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• pp.44-62
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• 2020

Objectives: The purpose of this study is to evaluate the effectiveness of herbal medicine for recovery and treatment of cervical intraepithelial neoplasia (CIN) after loop electrosurgical excision procedure (LEEP). Methods: We searched two english, one chinese and four korean database up to November 4, 2019. Randomised controlled trials (RCTs) were eligible. Primary outcome included Human papilloma virus (HPV) clearance rate and the effective ratio of treatment. And vaginal bleeding time and volume, improvement of symptoms, and recovery of wound were regarded as secondary outcomes. The risk of bias was assessed by two independent authors using the Cochrane risk of bias tool. Results: Of 47 screened, 10 RCTs were included. Number of participants per study ranged from 58 to 360. The studies which used HPV clearance rate as primary outcome were considered as low risk of bias. Most of the studies had considerable heterogeneity in terms of type of intervention, comparison and time-points for outcome measurement. Compared to LEEP alone, herbal vaginal suppository combined group showed favorable results for HPV clearance in patients (5 studies, n=627, 95% CI 1.26 to 1.55, I²=75%). And compared to LEEP alone, herbal external application also showed favorable results for HPV clearance in patients (2 studies, n=252, 95% CI 1.19 to 1.61, I²=86%). Three studies reported mild and temporary adverse events, and no serious adverse events were reported. Conclusions: The studies showed that herbal medicine can significantly effective on recovery of CIN after LEEP. However, included studies suffered from incomplete reporting, high or unclear risk of bias and substantial heterogeneity between studies. In the Future, further high-quality RCTs are needed to prove effectiveness of herbal medicine for CIN after LEEP and reduce the risk of bias.

• Asian-Australasian Journal of Animal Sciences
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• 제10권3호
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• pp.260-264
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• 1997

This study was conducted with adult cockerels to determine whether dietary RNA affects feed intake and renal weight and function, and if the responses are similar to dietary adenine. Chickens were ad libitum fed a RNA diet (100 g/kg) or an adenine diet (9.1 g/kg) for 14 d and catheterized in right jugular vein, hepatic portal vein and both urethers, and saline together with para-amino hippuric acid and sodium thiosulfate was continuously infused into them to evaluate renal functions. Dietary RNA reduced feed intake and body weight, and dietary adenine increased kidney weight expressed as a proportion of body weight (P < 0.05). Feed intake and body weight on the adenine diet and kidney weight on the RNA diet showed similar though non significant tendencies. No calculi were detected in the kidney in chickens fed either the RNA or adenine diets. Plasma inorganic phosphate (IP), Ca and 1,25 $(OH)_2$ vitamin $D_3$ concentrations were increased by dietary RNA and adenine, although the increases of IP and Ca in adenine-fed chickens were not significant. Uric acid and urea concentrations in the blood plasma were unaffected by dietary RNA or adenine. Both dietary RNA and adenine increased renal blood flow rates 3.5-3.7 fold, renal plasma flow rates 3.4-3.7 fold and glomerular filtration rates (GFR) 2.9-3.0 fold (p < 0.01). Clearance of urea, IP and Ca were also enhanced by dietary RNA, but not by dietary adenine. However, neither RNA nor adenine affected uric acid clearance. Only IP clearance was significantly augmented at the glomerular level by dietary RNA (p < 0.05). Glomerular filtration of uric acid, urea, IP and Ca and reabsorption of urea, IP and Ca at the renal tubule were increased by dietary RNA and adenine (p < 0.05), whereas tubular secretion of uric acid was decreased by both dietary treatments. It is concluded that dietary adenine is effective in changing renal function and P and Ca metabolism in chickens.

• 태양에너지
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• 제19권2호
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• pp.45-56
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• 1999

The performance of vertical and horizontal tubes with extended surface of rectangular and triangular cross section was investigated theoretically for boiling heat transfer. A simple method for numerical program assuming one-dimensional heat flow was used to predict the performance of these extended surface tubes. The object of this study was to predict the effects of the height, thickness, numbers and, clearance of the extended surface on boiling heat transfer. The results showed that extended surfaces are quite effective as compared to plane surfaces especially near the bum-out point and to promote heat flux in boiling heat transfer.