• 미생물학회지
• /
• 제27권1호
• /
• pp.48-55
• /
• 1989

HA 비드에 부착한 S. sanguis 세포는 방사능 측정시 칵테일 속에서 비드에 여전히 부착되어 있음으로 비드에 의한 방사능의 sel-absorpiton이 일어났으며 그 정도는 염산용액으로 비드를 용해시킬 때 측정한 반사능값의 34.5% 이었다. 현탁액으로 준비한 세포의 방사능 측정과는 달리 HA 또는 SHA에 부착한 세포의 경우에는 소량의 scintillation 용액(2.5ml) 사용에서 더 좋은 측정값을 얻었다 . HA 비드에 의한 칭은 약 18% 이었다. 부착 assay 에 사용할 HA 비드 준비에 보통 이용되는 3가지의 dqkdqjqdm 비교에서는 차이가 없었다. 부착실험용의 세균세포는 초소리파로 세균사슬을 끊었는데 30초간의 파절로 세포하나 또는 두개로 주로 구성된 현탁액을 얻을 수 있었다. 본 연구에서는 HA 비드에 부착한 S. sanguis 세포를 측정할 때 self-absorpiton이 일어남을 발견하였고 부착한 세균을 비드에서 탈락하거나 또는 비드를 용해시킨 후 측정함으로써 self-absorption을 제거할 수 있었다. 그리고 부착한 세균의 방사능 측정에서는, 적정의 칵테일량을 발견하여 사용하므로 측정값을 유의하게 증가시킬 수 있었다. 수 있었다.

• 설비공학논문집
• /
• 제19권2호
• /
• pp.169-174
• /
• 2007

In process of reinforced concrete (RC) box structure, the heat of hydration may cause serious thermal cracking. This paper reports results of hydration heat control in mass concrete using the oscillating heat pipe. There were three RC box molds ($1.2m{\times}1.8m{\times}2.4m$) which were different from each other. One was not equipped with pulsating heat pipe. The others were equipped with pulsating heat pipe. All of them were cooled with natural air convection. The pulsating heat pipe was composed of 10 turns of serpentine type copper pipe whose outer and inner diameters were 4 and 2.8 mm respectively. The working fluid was R-22 and charging ratio was 40% by volume. The temperature of the concrete core was approximately $55^{\circ}C$ in the winter without pulsating heat pipe. For a concrete with pulsating heat pipe, however, the temperature difference with the outdoor one reduced up to $12^{\circ}C$. The index figure of crack was varied from 0.75 to 1.38.

• 한국지반공학회논문집
• /
• 제33권11호
• /
• pp.45-57
• /
• 2017

연약지반의 압밀거동은 온도변화에 의하여 영향을 받는다. 연약 점토지반 내에 온도가 증가하면 간극수압이 증가하고 간극수압의 소산은 부피와 간극비를 감소시킨다. 또한 높은 온도는 간극유체의 점성을 감소시키므로 압밀속도가 빨라진다. 본 연구에서는 온도가 압밀침하량, 압밀시간, 간극수압과 같은 압밀거동에 미치는 영향을 분석하였으며, 이를 위하여 수리역학적(HM) 및 열수리역학적(THM) 거동에 대한 수치해석을 수행하였다. 열주입과 샌드드레인을 동시에 고려하였으며, 온도 변화 및 샌드드레인 직경 변화를 고려하여 해석을 수행하였다. 해석결과, 시료내부의 온도는 열원의 온도와 샌드드레인의 직경 증가에 따라 증가하는 것으로 나타났다. 또한 열주입은 과잉간극수압을 증가시키고 그에 따라 과압밀 영역에서는 추가적인 침하량을 유발하고 정규압밀 영역에서는 압밀시간을 감소시키는 것으로 나타났다.

• Journal of Dental Anesthesia and Pain Medicine
• /
• 제16권3호
• /
• pp.193-197
• /
• 2016

Background: Some patients with special needs exhibit intellectual disability, including deficits in cognitive skills and decreased quality of life. The purpose of this study was to retrospectively compare changes in body composition and hemodynamics during general anesthesia in patients with and without special needs. Methods: The backgrounds of patients who underwent oral maxillofacial surgery under general anesthesia were recorded from medical records. Intracellular water (ICW), extracellular water (ECW), stroke volume variation (SVV), and heart rate (HR) were recorded for 3 h after the start of anesthesia. Categorical data were compared using an unpaired t-test, and a P-value of less than 0.05 was regarded as significant. Numerical data were compared using the Bonferroni correction, and a P-value of less than 0.0125 was regarded as significant. Results: A total of 21 patients were included in the study: 10 patients without special needs (non-S-group) and 11 patients with special needs (S-group). There were no significant differences in patients' backgrounds, except with regard to height (P = 0.03). In both groups, ICW and ECW were maintained, although they were lower in the S-group compared to the non-S-group. SVV was maintained in both groups, although it was higher in the S-group than the non-S-group. HR was significantly lower in the S-group 1 h after induction of anesthesia (P < 0.003). Conclusions: Changes in hemodynamics due to body fluid imbalance should be monitored during general anesthesia, especially for patients with special needs.

• Tribology and Lubricants
• /
• 제35권2호
• /
• pp.99-105
• /
• 2019

This study presents an experimental investigation of the wear and oxidation of the bristles of a brush seal in a super-heated steam environment. We construct a model reflecting normal force and radial interference to predict the amount of wear. To monitor the volume loss of the bristle induced by the swirl phenomenon of the rotor, we measure the clearance between the rotor and the brush seal by using a non-contact 3-D device. We calculate the area by using the area-wise measurement method. Considering the obvious brush seal wear variables, we use two disks with different roughness($Ra=0.1{\mu}m$ and $100{\mu}m$) to determine the effect of roughness on wear. Considering an actual steam turbine, we utilize a steam generator and super-heater to generate a working fluid (0.95MPa, 523.15K) that has high kinetic energy. We observe the abrasion of the bristles in the hot steam environment through a scanning electron microscope image. This study also conducted energy dispersive X-ray (EDX) analysis for a qualitative evaluation of local chemistry. The results indicate that the wear and elimination of bristles occur on the disk with high roughness, and the weight increases due to oxidation. Furthermore these results, reveal that the bristle oxidation is accelerated more under super-heated steam conditions than under conditions without steam.

• 대한기계학회논문집B
• /
• 제37권9호
• /
• pp.799-805
• /
• 2013

본 논문에서는 나노유체를 사용한 평판형 집열기의 효율을 예측하기 위한 이론적인 연구를 수행하였다. 평판형 태양열 집열기 내부의 온도분포에 관한 해석적 해를 구하기 위해 무차원화된 2 차원 열 확산방정식을 풀었으며, 이 과정에서 흡광계수와 복사강도는 파장에 독립적이라고 가정하였다. 이렇게 주어진 식을 바탕으로, 물-기반 단일벽 탄소나노혼 나노유체를 작동유체로 사용할 경우 나노입자의 부피비, 열손실의 크기, 집열기의 높이에 따른 무차원 온도분포를 파악해 보았다. 마지막으로 나노유체 기반 평판형 집열기의 효율을 예측해 본 결과 일정 형상조건 이내에서 나노유체 태양열 집열기가 기존 집열기 보다 높은 효율을 가질 수 있음을 파악하였다.

• 드라이브 ㆍ 컨트롤
• /
• 제18권1호
• /
• pp.1-8
• /
• 2021

This paper presents research on methods for the reduction of forklifts' noise level for the increased comfort and safety of its operator. A cooling fan with a high air volume flow rate installed in the forklift acts as an important design parameter which efficiently cools the heat exchanger system, helping to transfer internal heat from the engine room to the outdoors with both transmitted and diffracted opening noises. The cooling fan contributes significantly to both the forklift's emitted sound power and the operator room's noise level, thereby necessitating research on the forklift's reduction of acoustic power level and transmission. A noise analysis for various fan models with a biomimetic design based on eagle-wing geometry was conducted. In addition to the acoustic power generation, the aerodynamic performance of the cooling blade is also strongly influenced by the design of airfoil distribution, thereby requiring optimization. The cooling fans were fabricated and installed in the forklift in order to check the efficacy of the forklift engine's cooling, and the final version of the fan was measured for its ability to lower acoustic power level and cool the engine room. This study explains the aerodynamic and acoustic features of the designed fans with the use of BEM analysis and forklift test results.

• 한국포장학회지
• /
• 제27권3호
• /
• pp.175-180
• /
• 2021

Although it has recently been regulated for use as an eco-friendly policy in Korea, the use of EPS (Expanded Polystyrene) cooling boxes, which are used as cold chain delivery insulation boxes for fresh agricultural and livestock products, is also increasing rapidly as e-commerce logistics such as delivery have increased rapidly due to COVID-19. Studies were conducted to optimize the EPS cooling container through internal air heat flow of CFD (Computational Fluid Dynamics) analysis and FEM (Finite Element Method) random vibration analysis using domestic PSD (Power Spectral Density) profile of the EPS cooling box to which the refrigerant is applied in this study. In the analysis of the internal air heat flow by the refrigerant in the EPS cooling box, the application of vertical protrusions inside was excellent in volume heat flow and internal air temperature distribution. In addition, as a result of random vibration analysis, the internal vertical protrusion gives the rigid effect of the cooling box, so that displacement and stress generation due to vibration during transport are smaller than that of a general cooling container without protrusion. By utilizing the resonance point (frequency) of the EPS cooling box derived by the Model analysis of ANSYS Software, it can be applied to the insulation and cushion packaging design of the EPS product line, which is widely used as insulation and cushion materials.

• 대한의용생체공학회:의공학회지
• /
• 제44권1호
• /
• pp.53-63
• /
• 2023

There have been many studies from the genetic system to physical activity and emotional expression such that there are gender differences. The purpose of this study was to determine how the structural characteristics of cortical thickness differ between males and females. This study used data from the Human Connectome Project (HCP). To analyze age-specific sexual dimorphisms of cortical thickness, selected 8-80 year old subjects were divided into five detailed age range groups according to each criterion. A total of 1,700 individual brain MRI T1 data were registered in stereotaxic space for analysis and classified into white matter (WM), gray matter (GM), and cerebro-spinal fluid (CSF). For surface-based analysis, the WM/GM surface was reconstructed from a spherical polygon model with 40962 vertices per hemisphere, and each vertex was extended to the GM/CSF boundary. Cortical thickness was then measured between each vertex using the t-link method. In the statistical analysis, intracranial volume was used as a covariate to exclude the effect of the difference in brain size of each individual, and the result of using age as a covariate was added to confirm the age effect within each group. Gender differences in cortical thickness had significant results by group. This may be an index to explain diseases with sexual dimorphism in prevalence or become a basis for explaining the characteristics of each sex that appear in behavior, personality, and aging. Therefore, the results of our study could be a criterion for age classification in future studies and for understanding 'normal' sexual dimorphism.

• 대한약침학회지
• /
• 제7권2호
• /
• pp.83-89
• /
• 2004

Objectives : This study is performed for the purpose of proving the efficacy of the Oriental medicine of swollen leg. Edema is defined as an increase in the extravascular(interstitial) component of the extracellular fluid volume, which may expand by several liters before the abnormality is recognized. We treated one case of patient with a swollen leg. Methods & results : We examined DITI before treatment and after treatment. We measured the circumference of thigh and calf every morning, so we compared with the values day after day. So we found the fact that leg swelling considerably decreased after treatment for 14 days. We followed up after discharge. Conclusions : Acupuncture, Aquacupuncture and Herbal medicine is possible to be effective for treating patients with a swollen leg.