• 대한설비공학회지:설비저널
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• 제6권1호
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• pp.1-8
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• 1977

This paper describes an experimental investigation which has been carried out with distilled water with the range of heat flux and pressure covering 7,400-28,000kcal/$m^2/h$ and 0.42-1.0332kg/$cm^{2}abs$, respectively. In this experiment, Nickel coated mirror surface heater of 5 cm O.D. was used as a heating source. The conclusions summerized as follows;1. The useful correlation of the test data for the heat transfer coefficient is presented as a function of the pressure. $$a/a_{s}=c{\times}p\;0.18$$ where a is the heat transfer coefficient and $a_s$ is the heat transfer coefficient at atmospheric pressure and p is the pressure, C is constant. 2. The bubble diameter near the heating surface and rising velocity increased with the heat flux. 3. A decrease in pressure results in the decrease of the number of nucleation sites and the increase of the bubble volume. 4. Bubble rising velocity differences are incrased maximumly up to $200\%$ of that at atmopheric pressure.

• 한국재료학회지
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• 제3권2호
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• pp.121-130
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• 1993

합성용질확산법으로 GaP 단결정을 성장시키고, 몇가지 성질을 조사하였다. 결정성장용 석영관을 전기로내에서 1.75mm/day의 속도로 하강시킴으로써 양질의 GaP 단결정을 성장하였다. 에치피트 밀도는 결정의 성장축 방향으로 3.8 ${\times}{10^4}$c$m^{-2}$부터 2.3 ${\times}{10^5}$c$m^2$이었다. 에너지갭의 온도의존성은 실험적으로 $E_g$(T)=[2.3383-(6.082${\times}{10^{-4}}$)$T^2$(373.096+T)eV로 구하여졌다. 저온에서의 광루미네센스 스펙트럼은 구속된 여기자의 복사재결합과 재결합 과정에 포논의 참여로 인하여 에너지갭 부근의 복잡한 선 스펙트럼이 나타났다. n형의 GaP내에서 Zn의 확산깊이는 확산시간의 제곱근에 비례하였으며, 확산계수의 온도의존성은 D(T)=3.2${\times}{10^3}$ exp(-3.486/KbTc$m^2$/sec이었다. p-nGaP 동종접합다이오드의 전기루미제센스 스펙트럼은 깊은 준위의 도너인 Zn-O 복합중심(complex center)과 Zn가 형성한 역셉터 준위사이의 도너-억셉터 쌍 재결합 천이에 의한 630nm의 발광과 에너지갭 부근의 케리어 재결합 처이에 의한 550nm의 발광으로 구성되었으며, 100mA보다 낮은 전류 영역에서 광자의 방출은 bane-filling 과정으로 이루어 진다.

• Journal of Korean Neurosurgical Society
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• 제57권4호
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• pp.283-288
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• 2015

Objective : This study aims to visualize the subjective symptoms before and after the treatment of whiplash injury using infrared (IR) thermography. Methods : IR thermography was performed for 42 patients who were diagnosed with whiplash injury. There were 19 male and 23 female patients. The mean age was 43.12 years. Thermal differences (${\Delta}T$) in the neck and shoulder and changes in the thermal differences (${\Delta}dT$) before and after treatment were analyzed. Pain after injury was evaluated using visual analogue scale (VAS) before and after treatment (${\Delta}VAS$). The correlations between ${\Delta}dT$ and ${\Delta}VAS$ results before and after the treatment were examined. We used Digital Infrared Thermal Imaging equipment of Dorex company for IR thermography. Results : The skin temperature of the neck and shoulder immediately after injury showed $1-2^{\circ}C$ hyperthermia than normal. After two weeks, the skin temperature was normal range. ${\Delta}T$ after immediately injuy was higher than normal value, but it was gradually near the normal value after two weeks. ${\Delta}dT$ before and after treatment were statistically significant (p<0.05). VAS of the neck and shoulder significantly reduced after 2 week (p=0.001). Also, there was significant correlation between ${\Delta}dT$ and reduced ${\Delta}VAS$ (the neck; r=0.412, p<0.007) (the shoulder; r=0.648, p<0.000). Conclusion : The skin temperature of sites with whiplash injury is immediately hyperthermia and gradually decreased after two weeks, finally it got close to normal temperature. These were highly correlated with reduced VAS. IR thermography can be a reliable tool to visualize the symptoms of whiplash injury and the effectiveness of treatment in clinical settings.

• Wind and Structures
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• 제5권2_3_4호
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• pp.151-164
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• 2002

Predictions of the pedestrian level wind speeds for the downtown area of Auckland that have been obtained by wind tunnel and computational fluid dynamic (CFD) modelling are presented. The wind tunnel method involves the observation of erosion patterns as the wind speed is progressively increased. The computational solutions are mean flow calculations, which were obtained by using the finite volume code PHOENICS and the $k-{\varepsilon}$ turbulence model. The results for a variety of wind directions are compared, and it is observed that while the patterns are similar there are noticeable differences. A possible explanation for these differences arises because the tunnel prediction technique is sensitivity to gust wind speeds while the CFD method predicts mean wind speeds. It is shown that in many cases the computational model indicates high mean wind speeds near the corner of a building while the erosion patterns are consistent with eddies being shed from the edge of the building and swept downstream.

• 대한화학회지
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• 제17권2호
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• pp.73-79
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• 1973

界面活性劑 dodecyl pyridinium bromide(D.P.B.) $20^{\circ}C$ 濃度 5∼100mM 水溶液中에서 0.1Mc~90Mc 超音波의 吸收 係數를 測定정하였다. 監 存在 與否에 關係없이 臨界 micelle 濃度(c.m.c.)以上의 濃度에서만 超音波超過 吸收가 觀測되었다. 超音波 吸收 曲線에서 D.P.B.水溶液 60mM附近에 超過 吸收 및 relaxation 振動數의 不連續的인 變化를 觀測하였다. 또 粘性係數, 電氣傳導度, 超音破速度들의 濃度曲線 에서도 같은 濃度에서 不連續的인 變化를 나타낸다. 따라서 이 濃度 附近에서 D.P.B.의 micelle의 性質에 變化가 일어나고 있다고 結論지을 수 있다. 超音波超過 吸收의 mechanism은 $M_2{\rightleftharpoons}M_1+2Br^-$ 反應에 基因됨을 알았다. 여기서 $M_2$,$ M_1$은 다른 型의 micelle이다. 正, 逆方向의 反應速度常數는 各各 $6.9 {\times} 10^5 sec^{-1)$, $6.7{\times}10^{10}sec^{-1}mole{-2}$임이 觀測되었다. 이 反應 mechanism의 自由 에너지, enthalpy, entropy 및 活性化에너지를 算出하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.57-57
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• 2010

Self assembled $Zn_{x-1}Cd_xS$ nanowires, synthesized on a Indium tin oxide coated glass substrate with low composition of Cd as x=0.09, were fabricated non-precursor via a co-evaporation method using of solid sources of CdS and ZnS. We studies that ZnCdS nanowires are dislocation-free and the single crystalline hexagonal wurtzite structure showed by transmission electron microscopy and selected area electron diffraction pattern. Cathode luminescence spectra showed an near band edge peak at 383nm originated from nanowires at 80K and 300K. Core level spectra of the Cd 3d, Zn 2p and S 2p in the ZnCdS nanorods were obtained by x-ray photoelectron spectroscopy. Prepared ZnCdS nanorods showed different shape with increase of substrate temperature at the growth.

• Advances in Traditional Medicine
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• 제7권2호
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• pp.128-132
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• 2007

Diarun plus, a polyherbal formulation containing herbal ingredients of folkloric Antidiabetic effect, was investigated for its effect on glycemic status in rats and mice. In contrast to conventional chemical induced diabetic animal models, changes in glycemic states were induced by physiological maneuvers. Results revealed that in euglycemic animals Diarun plus elicited little change (-10 to +10%), which was insignificant. In food deprivation/swim exercise induced hypoglycemia, Diarun plus reduced the degree of hypoglycemia in both rats and mice (from 38% to 27% in rats and 45% to 32% in mice). Similarly, the marked hyperglycemia induced by dextrose (70% in rats and 95% in mice) was reduced markedly to 8% and 25% respectively. The findings of the present study suggests that the ingredients of Diarun plus have the unique property of maintaining near euglycemic state irrespective of the altered glycemic state, and that have no significant effect in euglycemic condition.

• 대한환경공학회지
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• 제32권1호
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• pp.1-8
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• 2010

하구형 호수인 아산호(평택호)에서 방조제 근처의 A지점과 상류 하천이 유입되는 B지점을 선정하여, 퇴적물 성상과 퇴적물에서 발생하는 영양염 용출량을 측정함으로써 퇴적물이 아산호 수질에 미치는 영향에 대해 살펴보았다. 아산호의 퇴적물은 sandy loam으로 이루어져있고, 대부분의 인이 Nonapatite-P(64.7%)의 형태로 존재하고 있으므로, 수중의 pH 상승이나 혐기성 상태로의 전환 등에 의해 다량의 인이 퇴적물에서 용출되어 수체의 부영양화에 영향을 줄 수 있는 가능성이 있다. 4월이 6월에 비해 용출율이 높게 나타남을 알 수 있었다. 방조제 근처인 A지점에서는 질소, 유입지천의 합류점인 B지점에서는 인의 용출이 활발히 일어났다. 용출율과 퇴적물의 표면적을 이용해 일일 평균 용출량을 계산해보면, TN는 6,609 kg/d, TP은 3,877 kg/d로 유입지천으로부터 유입되는 TN의 93,616 kg/d 중 7.06%, TP의 17,590 kg/d 중 22.04%에 해당되는 값으로, 아산호의 퇴적물이 저수지 수질에 미칠 영향은 적다고 볼 수 있다.

• 한국안전학회지
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• 제13권4호
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• pp.113-120
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• 1998

Fatigue crack growth rates(i.e. crack initiation and crack growth of short and long crack) are investigated using commercial plates of high strength Al alloy 7075-T651 for the transverse-longitudinal(T-L) direction in air, water and sea water. Also, the evaluation direct current potential drop(D.C.P.D) method and the fractographical analysis by SEM are carried out. Near threshold region, short crack growth rates were much faster than those of comparable long cracks, and these short crack growth rates actually decrease with increasing crack growth and eventually merge with long crack data. Fatigue crack propagation rates in aggressive media(i.e. sea water) increase noticeably over three times those in air. One of the most significant characters in this phenomenon as a corrosion-fatigue causes an acceleration in crack growth rates. Sea water environment, particularly Cl$^{[-10]}$ solution brings the most detrimental effects to aluminum alloy. The result of fractographical morphology in air, water and sea water by SEM shows obvious dimpled rupture and typical striation in air, but transgranular fracture surface in water and sea water.

• Journal of Nuclear Fuel Cycle and Waste Technology
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• 제1권1호
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• pp.29-35
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• 2013

The United States Department of Energy (US DOE) is conducting research and development (R&D) activities under the Used Fuel Disposition Campaign (UFDC) to support storage, transportation, and disposal of used nuclear fuel (UNF) and wastes generated by existing and future nuclear fuel cycles. R&D activities are ongoing at nine national laboratories, and are divided into storage, transportation and disposal. Storage R&D focuses on closing technical gaps related to extended storage of UNF. Transportation R&D focuses on ensuring transportability of UNF following extended storage, and addressing data gaps regarding nuclear fuel integrity, retrievability, and demonstration of subcriticality. Disposal R&D focuses on identifying geologic disposal options and addressing technical challenges for generic disposal concepts in mined repositories in salt, clay/shale, and granitic rocks, and deep borehole disposal. UFDC R&D goals include increasing confidence in the robustness of generic disposal concepts, reducing generic sources of uncertainty that may impact the viability of disposal concepts, and developing science and engineering tools to support the selection, characterization, and licensing of a repository. The US DOE has also initiated activities in the Nuclear Fuel Storage and Transportation (NFST) Planning Project to facilitate the development of an interim storage facility and to support transportation infrastructure in the near term.