• Annals of Clinical Neurophysiology
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• 제1권1호
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• pp.47-54
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• 1999

The Doppler in neurosonologic examination could be applied to blood flow to determine its movement, the direction of its movement, and how fast it is. Indicies of the Doppler study denoted velocity, direction, and amount of RBC in the examined vessel. Systolic. diastolic, and mean blood flow velocities represent velocity of RBCs in a sample volume. Blood flow direction to the probe means direction of RBC to the probe. Size of amplitude displays toe amount of the RBCs passing the sample volume. Spectral broadening means presence of turbelence. The RBC movements and hemodynamics at the examined vessels can be estimated by analysis of Doppler indicies The formation and meaning of each of neurosonologic Doppler study is described in the present review.

• International Journal of Vascular Biomedical Engineering
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• 제1권2호
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• pp.30-35
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• 2003

Flow characteristics of blood flow in a micro channel were investigated experimentally using a micro-PIV (Particle Image Velocimetry) velocity field measurement technique. The main objective of this study was to understand the real blood flow in micron-sized blood vessels. The Reynolds number based on the hydraulic diameter of micro-channel for deionized (DI) water was about Re=0.34. For each experimental condition, 100 instantaneous velocity fields were captured and ensemble-averaged to get the spatial distributions of mean velocity. In addition, the motion of RBC (Red Blood Cell) was visualized with a high-speed CCD camera. The captured flow images of nano-scale fluorescent tracer particles in DI water were clear and gave good velocity tracking-ability. However, there were substantial velocity variations in the central region of real blood flow in a micro-channel due to the presence of red blood cells.

• 대한의생명과학회지
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• 제16권2호
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• pp.113-118
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• 2010

The purpose of this study was to investigate the effects of angular velocity on muscle strength and blood constituent. Subjects was classified into two groups, which were $60^{\circ}/sec$ angular velocity group (n=8), and $240^{\circ}/sec$ angular velocity group (n=8). Each group was applied to perform the isokinetic exercises on extensor muscle group for each 7 times in 10 set (3 days per a week for 3 weeks). Muscle strength was measured using peak torque of quadriceps femoris and blood constituent was measured using RBC, WBC and Hb. The peak torque was more significantly increased after 3 weeks application of $60^{\circ}/sec$ angular velocity group than $240^{\circ}/sec$ angular velocity group. The RBC and Hb were more significantly increased after 3 weeks application of $60^{\circ}/sec$ angular velocity group than $240^{\circ}/sec$ angular velocity group. But WBC was more significantly increased after 3 weeks application of $240^{\circ}/sec$ angular velocity group than $60^{\circ}/sec$ angular velocity group. These results indicate that $60^{\circ}/sec$ angular velocity isokinetic exercise application were effective treatment strategy on increase of muscle strength. But $240^{\circ}/sec$ angular velocity isokinetic exercise application were effective treatment strategy on immune protect system.

• 한국자기학회지
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• 제27권3호
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• pp.92-97
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• 2017

펄스자기장을 인체에 자극했을 때 몸 안에 있는 이온성 전해물질에 의해 유도전류가 발생하며, 최근에는 이를 활용하여 자기장 치료기술이 새롭게 연구 개발되고 있다. 본 연구에서는 강한 펄스자기장을 자극했을 때, 여러 층으로 응집되어 붙어있는 적혈구 연전형성의 변화를 동역학적으로 조사 분석하였다. 적혈구의 연전형성은 여러 가지 원인에 의해 발생하는데 물리학적으로 보면 적혈구 중심에 있는 $Fe^{+3}$ 이온에 의한 전기장 발생과 혈액 내에 녹아있는 음이온의 상호작용이 원인으로 고려된다. 본 연구에서 사용된 펄스자기장의 세기와 시간은 0.27 Tesla, 0.102 msec이고 펄스 반복시간은 1초이다. 인체에 가한 펄스자기장의 자극시간은 5분에서 10분, 15분, 20분까지 증가시켰고, 이에 따라 적혈구의 연전상태 변화를 동영상으로 조사하였다. 펄스자기장을 10분 동안 가했을 때 적혈구의 연전상태는 매우 호전되어 대체로 개별로 분리되었으며 slide glass 위에서 이동속도 역시 가장 활발하게 움직여서 $8{\times}10^{-4}m/sec$로 증가하였다. 그러나 20분까지 자기장 자극을 증가시키면 오히려 적혈구의 연전상태가 증가하고 활동성이 떨어지는 것을 확인하였다. 이에 대한 해석은 좀 더 체계적인 연구와 분석이 필요해 보인다.

• 한국환경농학회지
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• 제4권1호
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• pp.37-42
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• 1985

최근(最近) 오(汚)${\cdot}$폐수처리(廢水處理)에 있어서 고정생물막(固定生物膜)을 이용(利用)한 방법(方法)이, 처리장(處理場) 운전(運轉)에 요구(要求)되는 동력(動力) 및 인력(人力)의 절감(節減)이라는 장점(長點)으로 해서, 활발(活發)히 추진(推進)되어 오고 있으며 또한 국내(國內)에서도, 이를 적용(適用)한 처리장(處理場)이 점차 증가(增加)하고 있다. 본(本) 연구(硏究)는 고정생물막법(固定生物膜法)의 하나인 RBC(roating biological contactor; 회전생물막(回轉生物膜) 접촉체(接觸體))에 의(依)한 오수처리방법(汚水處理方法)을 실규모(實規模)의 pilot plant를 현장(現場)에 설치(設置), 5개월(個月) 간(間)의 운전(運轉)에 의(依)해 얻어진 결과(結果)를 분석(分析), 1984. 5. 16 환경청(環境廳)에서 고시(告示)(제(第)$84{\sim}8$호(號))한 오수정화시설중(汚水淨化施設中), 회전원판(回轉圓板) 접촉방법(接觸方法)에서 정(定)하는 설나기준(設羅基準)을 실제(實際) 처리장(處理場)에 어떻게 적용(適用)할 것인지에 대(對)한 검토(檢討)를 해보기 위(爲)해서였다. 회전판(回轉板)의 회전속도(回轉速度)와 체류시간(滯留時間)은 오수(汚水)의 BOD제거효율(除去效率)에 큰 상관관계(相關關係)를 가지며 회전판(回轉板)의 원주달도(圓周達度)가 $18{\sim}20m$/분(分)인 경우가 경제성(經濟性)이 있는 것으로 나타났으며 일반(一般) 가정하수(家庭下水)에 대(對)한 RBC조내(槽內)의 체류시간(滯留時間)은 120분(分)(2시(時) 간(間))정도(程度)에서도 BOD제거율(除去率)이 90% 이상(以上)이 됨을 알 수 있었다. 그리고 고농도(高濃度) 오빙(汚氷)(BOD $250{\sim}400mg/l$)인데 대(對)해서도 제거율(除去率) $85{\sim}90%$정도(程度)로 양호하였다.

• 한국양식학회지
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• 제6권4호
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• pp.311-321
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• 1993

Ammonia accumulation is regarded as the limiting factor of the first priority in water qualities of aquatic culture systems. Nitrification efficiency and characteristics in seawater were evaluated using Rotating Biological Contactor (RBC) process as a part of the recycling water treatment facilities for marine fish culture system. Ammonia removal efficiency regarded 99.7 to $83.7\%$ at the ammonia surface loading rates of 48 to $393 mg/m^2$ -day. RBC process was able to withstand to the fluctuation of influent ammonia concentrations and loading and produced the stable effluent. The mathematical model on the fixed-film biological reactor developed by Kornegay seemed to be suitable to RBC process kinetic evaluation for the recycling water treatment of the marine fish culture system. Area capacity constant (P) and half-velocity constant (Ks) in the model were 0.188g/m^2$-day and 1.25mg/l, respectively.

• International Journal of Vascular Biomedical Engineering
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• 제1권1호
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• pp.24-31
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• 2003

As endothelial cells are subject to flow shear stress, it is important to determine the detailed velocity distribution in microvessels in the study of mechanical interactions between blood and endothelium. This paper describes a velocity field of the arteriole in the rat mesentery using an intravital microscope and high-speed digital video system obtained by a highly accurate PIV technique. Red blood cells (RBCs) velocity distributions with spatial resolutions of $0.8{\times}0.8{\mu}m$ were obtained even near the wall in the center plane of the arteriole. By making ensemble-averaged time-series of velocity distributions, velocity profiles over different cross-sections were calculated for comparison. The shear rate at the vascular wall also evaluated on the basis of the ensemble-averaged profiles. It was shown that the velocity profiles were blunt in the center region of the vessel cross-section while they were steep in the near wall region. The wall shear rates were significantly small, compared with those estimated from the Poiseuille profiles.

• 한국가시화정보학회지
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• 제16권1호
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• pp.15-20
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• 2018

For the measurement of biophysical properties related with cardiovascular diseases (CVD), various microfluidic devices were proposed. However, many devices were monitored by optical equipment. Ultrasound measurement to quantify the biophysical properties can provide new insights to understand the cardiovascular diseases. This study aims to check feasibility of microfluidic device for ultrasound image analysis based on 3D printer. To facilitate acoustic transmission, agarose solution is poured around 3D mold connected with holes of the acrylic box. By applying speckle image velocimetry(SIV) technique, flow information in the bifurcated channel was estimated. Considering that ultrasound signal amplitude is determined by red blood cell (RBC) aggregation, RBC aggregation in the bifurcated channel can be estimated through the analysis of ultrasound signal. As examples of microfluidic device which mimic the CVD model, velocity fields in microfluidic devices with stenosis and aneurysm were introduced.

• 대한의용생체공학회:의공학회지
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• 제31권2호
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• pp.99-105
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• 2010

In order to obtain velocity profile of blood flow with high spatial resolution, a micro PIV technique consisted of a fluorescent microscope, double-pulsed YAG laser, cooled CCD camera was applied to in-vitro blood flow experiment through a micro round tube of a diameter $100{\mu}m$. Velocity distributions of blood flow for rabbit were obtained. The viscosity profiles for shear rate were found at flowing condition. To provide hemorheological characteristics of blood flow, the viscosities for shear rate were evaluated. The viscosity of blood also steeply increase by decreasing shear rate resulting in Non-Newtonian flow, especially in low shear rate region caused by RBC rheological properties. The results show typical characteristics of Non-Newtonian characteristics from the results of velocity profile and viscosity for blood flow. From the inflection points, cell free layer and two-phase flow consisted with plasma and suspensions including RBCs can be separated.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2006년도 추계학술대회 논문집
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• pp.111-112
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• 2006

In order to investigate flow characteristics of blood flow in a micro tube ($100{\mu}m$ in diameter) according to hematocrit, in-vitro experiments were carried out using a micro-PIV technique. The micro-PIV system consists of a microscope, a 2 head Nd:YAG laser, a 12 bit cooled CCD camera and a delay generator. Blood was supplied into the micro tube using a syringe pump. Hematocrit of blood was controlled to be 20%, 30% and 40%. The blood flow has a cell free layer near the tube wall and its thickness was changed with increasing the flow rate and hematocrit. The hemorheological characteristics such as shear rate and viscosity were evaluated using the velocity field data measured. As the flow rate increased, the blunt velocity profile in the tube center was sharpened. The viscosity of blood was rapidly increased with decreasing shear rate, especially in the region of low shear rate, changing RBC rheological properties. The variation of velocity profile and blood viscosity shows typical characteristics of Non-Newtonian fluids. On the basis of inflection points, the cell free layer and two-phase flow consisting of plasma and suspensions including RBCs were clearly discriminated.