• 대한전자공학회논문지
• /
• 제21권5호
• /
• pp.41-45
• /
• 1984

양질의 에피택셜 층을 성장시키기 위해서는, 에피택셜 층을 성장시키기 직전에 HCl 가스를 사용하여 실리콘 기판을 에칭하는 과정이 거의 언제나 포함된다. 본 논문에서는, 대기압[1 기압]과 감압[0.1기압]에서 HCl 가스 농도와 에칭 온도의 변화에 따른 에칭속도 및 에치-피트 생성에 관하여 조사하였다. 그 결과, 대기압 공정과 감압 공정 모두 에칭 속도는 HCI 가스 농도의 2승[X ]에 비례하였으며, 명목상 활성화 에너지는 0∼11 Kcal/mole인 것으로 나타났다. 이러한 결과로부터, 감압 공정에서 HCl 가스에 의해 실리콘이 에칭되는 것은 대기압 공정에서와 같이 다음과 같은 반응에 의해 일어난다고 예측된다; Si + 2HCl ↔SiCl2 + H2.

• The Korean Journal of Physiology
• /
• 제11권2호
• /
• pp.23-31
• /
• 1977

It is Proposed in the Present study to investigate the effects of TTX intravenously or intrahypothalamically administered on the arterial blood pressure and respiration and also to explorc effect of intrahypothalamically administered TTX on the pressor responses to electrical stimulation in the hypothalamus. The results obtained are as follows; 1) The pressor responses to electrical stimulation in the hypothalamus were markedly reduced after administration of TTX. In the $0.01\;{\mu}g/kg$ of TTX administered group, the pressor responses were almost abolished in 6 minutes and there was no tendency toward recovery throughout the experiment. 2) In $0.01\;{\mu}g/kg$ of TTX administered group, the mean arterial blood pressure and heart rate-were gradually reduced while there was a transient increase in respiratory rate followed by slow recovery thereafter. On the other hand no changes in arterial blood pressure, heart rate an4 respiration were observed in $0.005\;{\mu}g/kg$ TTX administered group. 3) Following intravenous administration of $1\;{\mu}g/kg$ TTX, the arterial blood pressure and heart rate were slowly reduced by 60 minutes while no marked changes were found in respiration. From the results of present study it is strongly suggested that TTX exerts its depressant effect not only on peripheral nerves but also on central nervous system.

• 한국응용과학기술학회지
• /
• 제8권2호
• /
• pp.183-189
• /
• 1991

This study aimed to find out the effect of freeze-drying leek against cholesterol feeding rats on the cholesterol and lipid in serum, hemolysis in erythrocyte and blood pressure in rats tall. In this experiment, male rats of Wistar strain were used. The rats were divided into 3 groups in 8 weeks : basal diet, 1% cholesterol and 1% cholesterol and 1% leek. The followings are the results of this experiment. 1. In vitro, leek-ext, reduced the hemolysis. 2. Leek reduced VLDL, LDL/HDL-cholesterol in serum. 3. Leek reduced the blood pressure in rat's tail. 4. Leek reduced the fatty change in liver caused by cholesterol treatment. This experiment showed that leek-addition group had portective effect against cholesterol fed and decresed VLDL, LDL/HDL-cholesterol in serum, Leek alleviated hemolysis in erythrocyte, blood pressure in rat's tail and fatty change in liver. Therefore, this experiment concluded that leek has defensive power against cholesterol.

• Wind and Structures
• /
• 제32권3호
• /
• pp.227-238
• /
• 2021

This study analyzed the pressure patterns and local pressure of tall buildings with corner modifications (recessed and chamfered corner) using wind tunnel tests and proper orthogonal decomposition (POD). POD can distinguish pressure patterns by POD mode and more dominant pressure patterns can be found according to the order of POD modes. Results show that both recessed and chamfered corners effectively reduced wind-induced responses. Additionally, unique effects were observed depending on the ratio of corner modification. Tall building models with recessed corners showed fluctuations in the approaching wind flow in the first POD mode and vortex shedding effects in the second POD mode. With large corner modification, energy distribution became small in the first POD mode, which shows that the effect of the first POD mode reduced. Among building models with chamfered corners, vortex shedding effects appeared in the first POD mode, except for the model with the highest ratio of corner modifications. The POD confirmed that both recessed and chamfered corners play a role in reducing vortex shedding effects, and the normalized power spectral density peak value of modes showing vortex shedding was smaller than that of the building model with a square section. Vortex shedding effects were observed on the front corner surfaces resulting from corner modification, as with the side surface. For buildings with recessed corners, the local pressure on corner surfaces was larger than that of side surfaces. Moreover, the average wind pressure was effectively reduced to 88.42% and 92.40% in RE1 on the windward surface and CH1 on the side surface, respectively.

• 대한의용생체공학회:의공학회지
• /
• 제31권5호
• /
• pp.351-358
• /
• 2010

In the automatic non-invasive blood pressure measurement device, the oscillometric method iswidely used. In the oscillometric method, the step-wise deflation has the advantage of the robustness for the motion artifacts than the linear deflation method. But it has the disadvantage of its longer measurement time because we need to detect two or more pulses in a certain cuff pressure step. In this study, we suggest the modified step-wise deflation method to overcome this limitation while maintaining the general concept of step-wise deflation. Using one valid pulse in each step and the deflating valve control during the diastolic period, the measurement time could be reduced. In order to verify the accuracy of the proposed algorithm, we compared the blood pressure values from the suggested method and the blood pressure values from the conventional auscultation method. The mean and standard deviation were -0.50${\pm}$5.3mmHg and 2.08${\pm}$4.75mmHg, for systolic and diastolic blood pressure respectively. The measurement time can be reduced up to the half of conventional step-wise deflation method.

• The Journal of Korean Physical Therapy
• /
• 제19권5호
• /
• pp.51-63
• /
• 2007

Diabetic foot ulcers result from abnormal mechanical loading of the foot, such as repetitive pressure applied to the plantar aspect of the foot while walking. Diabetic peripheral neuropathy causes changes in foot structure, affecting foot function and subsequently leading to increased plantar foot pressure, which is a predictive risk factor for the development of diabetic foot ulceration. To early identify the insensitive foot makes it possible to prevent diabetic foot ulceration and to protect the foot at risk from abnormal biomechanical loading. Abnormal foot pressures can be reduced using several different approaches, including callus debridement, prescription of special footwear, foot orthosis. injection of liquid silicone, Achilles tendon lengthening, and so forth. Off-loading of the diabetic wound is a key factor to successful wound healing as it is associated with reduced inflammatory and accelerated repair processes. Pressure relief can be achieved using various off-loading modalities including accommodative dressing, walking splints, ankle-foot orthosis, total contact cast, and removable and irremovable cast walkers.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 춘계학술대회논문집B
• /
• pp.619-624
• /
• 2000

The purpose of present study is to investigate for reducing micro pressure waves generated according to train speeds $(240km/h{\sim}380km/h)$ through tunnels with countermeasures as followings; the hood configuration in tunnel entrance. We developed hoods for tunnel of 0.5 km length in the condition of tunnel cross-section area of $107m^2$ on the slab track. According to the results the maximum micro-pressure wave is reduced by 41.2% for the slit hood installed at the entrance of the tunnel and reduced by 47.7% for the slit hood installed at the entrance of the tunnel and the $45^{\circ}$ slanted portal at the exit of the tunnel

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
• /
• pp.121.1-121.1
• /
• 2014

Recently, much attention has been given to plasma production under liquid and its applications [1]. However, most of plasma production techniques reported so far utilize high voltage dc, ac, rf or microwave power [2], where damage to discharge electrodes and small discharge volume are remained issues. As an alternative of plasma production method under liquid, we have proposed pulsed microwave excited plasma using slot antenna, where damage to the slot electrode can be minimized and plasma volume can be increased. We have also reported improvement of treatment efficiency with use of reduced-pressure condition during the discharge [3]. To realize low pressure conditions in liquid, various alternative technique can be considered. One possible technique is simultaneous injection of microwave power and ultrasonic wave. Ultrasonic wave induces pressure fluctuation with the wave propagation and is so far used for cavitation production in the water. We propose utilization of reduced pressure induced by ultrasonic cavitation for improvement of the plasma production. Correlation between the plasma production and the ultrasonic power will be discussed.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2006년도 춘계학술대회논문집
• /
• pp.1011-1014
• /
• 2006

Turbo blower generates high peaks when it operates at high pressure region. The fan of the air-cleaner system, operates especially high pressure region due to several filters, generates high noise level. In this case, the tonal sound of BPF makes people annoyance. The blower of air-cleaner has several high resistance filters in its inlet area and rotates above 900rpm Moreover, for the compact design, the size of the blower should be reduced 10%. The reduced diameter of blower makes low flow rate and high noise level. In order to reduce the noise, new blade shape was suggested and optimized

• 열처리공학회지
• /
• 제19권5호
• /
• pp.262-269
• /
• 2006

The development of eco-friendly low pressure carburizing system with high pressure gas quenching(LPC-GQ, 500kg/charge) led to new stage in the fundamental case-hardening treatments. This is due to its ability to provide tighter tolerances on the carburizing process with notable reductions in distortion of the carburized and hardened workpiece. This system is characteristics by high uniformity and reproducibility of heat treatment results, absence of an intergranular oxidation layer, carburizing of complex shapes, reduced cycle time, low operating costs, simplified production, eliminate post washing, and reduced grinding costs.