• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
• /
• pp.183-191
• /
• 2004

The burning characteristics of interacting droplets with internal circulation in a convective flow are numerically investigated at various Reynolds numbers. The transient combustion of 2-dimensionally arranged droplets, both the fixed droplet distances of 5 radii to 40 radii horizontally and 4 radii to 24 radii vertically, is studied. The results obtained from the present numerical analysis reveal that the transient flame configuration and retardation of droplet internal motion with the horizontal or vertical droplet spacing substantially influence lifetime of interacting droplets. At a low Reynolds number, lifetime of the two droplets with decreasing horizontal droplet spacing increases monotonically, whereas their lifetime with decreasing vertical droplet spacing decreases due to flow acceleration. This flow acceleration effect is reversed when the vertical droplet spacing is smaller than 5 radii in which decreasing flame penetration depth causes the reduction of heat transfer from flame to droplets. At a high Reynolds number, however, lifetime of the first droplet is hardly affected by either the horizontal droplet spacing or flow acceleration effect. Lifetime with decreasing vertical droplet spacing increases due to reduction of flame penetration depth. Lifetime of interacting droplets exhibits a strong dependence on Reynolds number, the horizontal droplet spacing and the vertical droplet spacing and can be con-elated well with these conditions to that of single burning droplet.

• 한국기계가공학회지
• /
• 제2권2호
• /
• pp.98-105
• /
• 2003

In the experimental study, wire EDM was conducted for cold die steel by changing the Wire electrode, peak discharge current and number of finish cut. From the micro structure analysis of SEM photographs, the size of irregular welded and added component on the EDMed surface is decreasing and size of EDMed plane surface is increasing as the decreasing peak current and increasing number of finish cut. From the analysis of coating effect, Zn component is highly contained in Br and Zn Wire EDMed surface and copper component is highly contained in Br and Al wire EDMed surface. Hardness values are Increasing as the increasing peak current and decreasing the number of finish cut The value of hardness is decreasing as Cu, Al, Zn and Br wire electrode because of the residual austenite effect of solid solution copper on solidification, and finally EDMed surface has the highest hardness values for every wire electrode. Yield strength values becomes larger and bending strength values become smaller due to the increasing the hardness. These results are increased as increasing brittleness with hardness.

• 대한기계학회논문집
• /
• 제13권4호
• /
• pp.670-679
• /
• 1989

본 연구에서는 항공기 구조용 재료로서 널리 사용되는 국산 고장력 7075-T73 알류미늄 합금을 준비하고 일정진폭하중 및 단일과대하중에 의한 피로균열 진전거동에 미치는 두께의 영향과 이의 기구를 검토하였다.

• 열처리공학회지
• /
• 제3권2호
• /
• pp.20-31
• /
• 1990

This investigation has been carried out to make clear the effect of deformation temperature, strain rate and grain size on the tensile properties of 304L stainless steel. Tensile properties of the metastable austenitic 304L steel remarkably influenced by deformation temperature. Tensile strength increased with decreasing deformation temperature and the elongation showed maximum value near $40^{\circ}C$. In order to obtain the high elongation, a large amount of deformation is available in austenite before martensitic transformation and the martensite has to be induced gradually. Tensile strength and elongation increased with decreasing grain size. The temperature representing the maximum elongation shifted to low temperature and the peak width of elongation became broaden with decreasing austenite grain size. The volume fraction of strain induced martensite decreased with decreasing austenite grain size. As the strain rate increase, the temperature representing the maximum elongation value shifted to high temperature and volume fraction of strain induced martensite decreased.

• 동의생리병리학회지
• /
• 제24권6호
• /
• pp.996-1003
• /
• 2010

This study was performed to investigate the effect of promoting gastrointestinal function and inhibiting of decreasing body temperature of ginger extract(Zingiber officinale) in rats. In order to elucidate the gastrointestinal function and inhibiting effect of body temperature of native ginger and improved ginger, water extracts of ginger were orally administrated into rats. The results are as follows: The gastrointestinal transit time was significantly decreased in native ginger(7.66hrs) and improved ginger(7.72hrs) extract administrated groups compare to control group(8.44hrs). The mean red faecal weight was increased in native ginger(30.6%) and improved ginger(31.1%) extract administrated groups compare to control group(24.9%) for 24hrs. Inhibiting effect of decreasing body temperature induced by serotonin was increased in native ginger($1.116^{\circ}C$) and improved ginger($1.416^{\circ}C$) extract administrated groups compare to positive control group($0.384^{\circ}C$) during 40 minutes. Gastrin and CGRP immunoreactive density was more strongly expressed in native ginger and improved ginger extract administrated groups compare to control group. Serotonin immunoreactive density was more weakly expressed in native ginger and improved ginger extract administrated groups compare to control group. These results suggest that ginger extracts may enhance physiological activity such as gastrointestinal motility, protection of mucosa and gastric acid secretion in gastrointestinal tracts, and inhibits decreasing body temperature

• 경영과학
• /
• 제32권3호
• /
• pp.29-36
• /
• 2015

In this research, we analyze the sensitivity of the network density to the estimates for the Bass model parameters with both theoretical model and a simulation. Bass model describes the process that the non-adopters in the market potential adopt a new product or an innovation by the innovation effect and imitation effect. The imitation effect shows the word of mouth effect from the previous adopters to non-adopters. But it does not divide the underlying network structure from the strength of the influence over the network. With a network based Bass model, we found that the estimate for the imitation coefficient is highly sensitive to the network density and it is decreasing while the network density is decreasing. This finding implies that the interpersonal influence can be under-looked when the network density is low. It also implies that both of the network density and the interpersonal influence are important to facilitate the diffusion of an innovation.

• 약학회지
• /
• 제29권4호
• /
• pp.206-215
• /
• 1985

1) Puerariae Radix butanol ext. (100, 200, 400mg/kg, p.o. single treatment) alone partly showed blood pressure decreasing effect in SHRs and increasing effect of urinary volume in normal rats. 2) Cadmium nitrate (10mg/kg, s.c. single treatment) induced toxicity such as body weight decreasing effect, antidiuretic effect and muscle relaxant effect such as pull-up test, traction test and rota rod test in rats. However, Puerariae Radix butanol ext. (100, 200, 400mg/kg, p.o. single treatment) showed antidotal effects on the above and also in acute toxicity test when coadministered with both of them. 3) Cadmium nitrate (1mg/kg, s.c. 7 days consecutive treatment) did not showed toxicity in body weight change, blood pressure, change, serum biochemical parameters in rats. Puerariae Radix butanol ext. (100, 200, 400mg/kg, p.o. 7 days consecutive treatment) did not also showed any antidotal effects when coadministered with both of them for 7 days.

• Journal of Acupuncture Research
• /
• 제19권1호
• /
• pp.39-45
• /
• 2002

Objective : This study was conducted with the purpose to evaluate the decreasing effect of the blood pressure on the hypertensive patients who were given to acupuncture on Iny$\check{o}$ng(ST9). Methods : We investigated the patients who had essential or secondary high blood pressure in the kwangdong oriental hospital from October 2000 to September 2001 as an experimental group and the non-hypertensive patients as a control group. Result : While the acupuncture was done in the experimental group, there was statistically significant decrease of the blood pressure, There was no statistically significant changes of blood pressure in the control group. Conclusion : We found that acupuncture on Iny$\check{o}$ng(ST9) has statistically significance in decreasing blood pressure to the experimental group while it hasn't to the control group. We also found out the decreasing effect of blood pressure lasted for two hours at least.

• 한국연소학회지
• /
• 제12권3호
• /
• pp.24-32
• /
• 2007

A theoretical model was developed for rotary kiln and computational study was conducted to find the effect of feeding characteristics. One dimensional model with the variations of heating distribution, length of heating zone, excess air ratio and revolution was considered. The comparison of parallel-flow rotary kiln with that of counter-flow was conducted. For parallel-flow type, it is found that the variation of temperature of solid is not great for the zone that is following flame-heating zone. This zone is good to take the special treatment because thermal deviation is small and contacting time is enough for another treatment. Increase of excess air ratio have the effect of decreasing solid temperature. But this effect of decreasing solid temperature goes small for the great excess air ratio. The heating is efficient for the flame which has the maximum heating at the central region of the full length.

• 한국식품영양과학회지
• /
• 제19권1호
• /
• pp.21-26
• /
• 1990

The aim of this study is to investigate effects of Prunus mume extract on gastric secretion in rats and experimentally carbon tetrachloride-induced liver damage of rabbits. The groups of Prunus mume extract showed excellent increasing effect in total acidity and peptic activity and decreasing effect on gastric volume than the control group whereas clear differences were not found between sample adminstered group and control group in gastric pH. In liver function test Prunus mume extract exhibited rapid recuperation of liver function that is sGPT activity showed an apparant decreasing effect from the 6th day total cholesterol and alkaline phosphatase level from the 10th day respectively compared to the control group in carbon tetrachloride-intoxicated rabbits. It is, is suggested that Pruns mume extract can be used as the stomachics to promote the gastric digestion by increasing the peptic activity and health food to shorten the recovery time from liver diseases.