• 청정기술
• /
• 제16권2호
• /
• pp.124-131
• /
• 2010

슬러리 기포탑을 이용하여 수산화칼슘 농도(0.16~0.64 wt%), 계면활성제 농도(2~16 wt%), 총 부피유량(3~6 L/min) 및 $CO_2$ 유량의 부피분율(0.3~0.6)이 탄산칼슘의 morphology, 결정구조, 입자의 크기, 입자 간의 응집화, 비표면적에 미치는 영향을 알아보았다. 실험에 사용한 반응기는 높이가 1.0 m이고 직경이 0.11m, 그리고 중앙에는 직경 4 cm인 튜브가 들어있는 슬러리 기포탑이다. 실험에 사용한 음이온 계면활성제 Dispex N40은 탄산칼슘 합성에 있어 반응 속도에 영향을 주어 반응 종결 시간을 감소시켰다. Dispex N40의 농도가 2 wt%일 때 수산화칼슘의 포화농도인 0.16 wt%에서 이산화탄소의 유량에 따른 침강성 탄산칼슘의 morphology를 살펴보면 반응 속도가 증가할수록 결정의 형태는 단일 결정으로 존재하는 입자들이 많아졌다. Dispex N40은 탄산칼슘의 crystal의 성장과 입자와 입자간의 응집 현상에 영향을 주어 탄산칼슘의 평균 입도를 변화시켰다. 또한 $0.9 L/min\;CO_2$ 유량에서 수산화칼슘의 농도가 0.64 wt%일 때 2 wt%의 계면활성제 첨가로 인해 비표면적을 $35m^2/g$에서 $44m^2/g$로 크게 증가시켰다.

• 한국운동역학회지
• /
• 제31권2호
• /
• pp.113-118
• /
• 2021

Objective: The purpose of this study was to investigate differences of landing strategy between people with or without chronic ankle instability (CAI) during double-leg drop landing. Method: 34 male adults participated in this study (CAI = 16, Normal = 18). Participants performed double-leg drop landing task on a 30 cm height and 20 cm horizontal distance away from the force plate. Lower Extremities Kinetic and Kinematic data were obtained using 8 motion capture cameras and 2 force plates and loading rate was calculated. Independent samples t-test were used to identify differences between groups. Results: Compared with normal group, CAI group exhibits significantly less hip internal rotation angle (CAI = 1.52±8.12, Normal = 10.63±8.44, p = 0.003), greater knee valgus angle (CAI = -6.78±5.03, Normal = -12.38 ±6.78, p = 0.011), greater ankle eversion moment (CAI = 0.0001±0.02, Normal = -0.03±0.05, p = 0.043), greater loading Rate (CAI = 32.65±15.52, Normal = 18.43±10.87, p = 0.003) on their affected limb during maximum vertical Ground Reaction Force moment. Conclusion: Our results demonstrated that CAI group exhibits compensatory movement to avoid ankle inversion during double-leg drop landing compared with normal group. Further study about how changed kinetic and kinematic affect shock absorption ability and injury risk in participants with CAI is needed.

• Journal of Yeungnam Medical Science
• /
• 제6권1호
• /
• pp.69-80
• /
• 1989

1987년 10월 1일부터 1988년 9월 30일까지 늑막삼출로 본원에 입원한 환자 138명을 대상으로 삼출액의 백혈구치와 임파구의 분포, pH, 생화학적 검사, 결핵균 검사, 암세포학적 검사 및 경피적 늑막 조직 생검을 실시하여 다음과 같은 결과를 얻었다. 1. 삼출성 늑막염은 결핵성이 57.3% 악성이 26.8%로 악성의 빈도가 점차 증가하고 있으며 결핵성은 전 연령에 걸쳐 고른 분포를 나타내었고 연령이 높을수록 악성의 빈도가 증가하였다. 2. 결핵성 늑막삼출의 경우 늑막액의 결핵균도말 및 배양 양성율은 3.7%로 매우 낮았으며 조직생검에 의한 진단율은 75%로서 늑막천자 및 조직생검에 의한 진단율은 78.7%이었다. 3. 악성 늑막삼출의 경우 세포학적 검사에서 암세포의 발견율은 42.3%이었고 조직학적으로 악성인 경우는 60%로서 세포학적 검사 및 조직검사의 진단융은 71%이었고 조직학적으로 확인된 악성 늑막삼출은 선암이 가장 많았다. 4. 삼출액의 성상을 비교하면 pH, 백혈구치, 단백양, 당치 등은 유의성이 있으나 두군의 감별에는 도움이 되지 않으며 임상에서 많이 고려되는 lympho-dominant삼출이 악성에서도 빈발하므로 임상적 감별진단에 큰 도움이 되지 않았다. 5. 조직학적으로 비특이성 염증반응인 경우 추적검사에서 결핵성이 52.2%, 악성이 26%, 원인불명이 21.8%로서 결핵이나 암의 가능성을 배재할 수 없었다. 이상의 결과로 생화학적 검사는 악성과 결핵성의 감별진단에 별 도움을 주지못하며 악성 늑막삼출도 증가하고 있으므로 진단이 불확실한 경우에는 반복된 세포진검사 및 늑막조직 생검을 병행하여야 할 것으로 사료된다.

• 한국의상디자인학회지
• /
• 제7권3호
• /
• pp.75-81
• /
• 2005

The experiment aimed at knowing the effect of physiology and psychology according to season on color preference. Two tests, one of the spring and the other of the autumn was conducted. Seventy subjects with normal color vision served as subjects. The subjects entered a bioclimatic chamber controlled at a temperature of $25\pm1^{\circ}C$, a relative humidity of $50\pm5\%$ and a light of 1000 1x. The subjects wearing white shirts and trousers sat quietly on a sofa for one our. Sensation from warm to cool colors might be possibly different individually Therefore, a subject asked to array 41 randomly placed cloth colors from very warm to very cool colors during rest quietly for one our. All subjects arrayed these cloth colors in the order from red through yellow and green to blue, which had the reproducibility. After rest, they were instructed to choose a single one out of 41 cloth colors, preferred by themselves, every 10min during one our 0-ring test were measured to red, yellow, white, blue, black, favorite color, and dislike color. Most subjects preferred warmer color in April than in December. Tympanic temperature was significantly lower in December than in April. Finger presser was significantly higher in like color than in dislike color but it was no significant differences between spring and autumn. The preferring the warm color in April toward summer when basal metabolic rate is decreased than in December toward winter when it is increased can explain that physiology reaction by load error between actual core temperature and set-point induces psychological reaction to pursue visual alliesthesia. Our present experiment revealed that the preferred color could be determined by the relationship between the internal temperature and its set point according to season. It should be emphasized that the alliesthesia was observed also in the realm of visual system.

• Parasites, Hosts and Diseases
• /
• 제41권3호
• /
• pp.141-145
• /
• 2003

This study was performed to investigate the prevalence of theileriosis and to compare the prevalence of this disease in Korean native cattle reared under different environmental conditions, namely, in a grazing area and a non-grazing area by polymerase chain reaction. Three hundred and one Korean native cattle (276 cows and 25 bulls) that had not received prior treatment or been vaccinated to prevent theileriosis were examined by PCR for Theileria sergenti infection from 2001 to 2002. In our study, the parasitemia range in T. sergenti-positive cattle by microscopy were from 0.1 to 3％ (mean 0.8％). In terms of mean prevalence, 204 of the 301 Korean native cattle (67.8％) were positive reaction by PCR. Our results also revealed that the infection rate among cows (70.3％) was significantly higher than that among bulls (40.0％) (p < 0.01). T. sergenti infection among the over 3 year-old-group (75％) had a significant higher prevalence than that among the less than 3 year-old-group (61.8％) (p < 0.05). Our data also showed that grazing areas (76.1％) had the significant higher prevalence than non-grazing areas (51％) (p < 0.001). In conclusion, this study demonstrates that the prevalence of T. sergenti infection is high and that its prevalence in grazing cattle is higher than that in non-grazing cattle, Therefore, life-long treatment and the development of an optimal vaccine are needed to reduce the numbers of bovine theileriosis in both grazing and non-grazing areas.

• 한국연소학회지
• /
• 제4권2호
• /
• pp.63-74
• /
• 1999

The effects of EGR and premixedness on NO formation have been numerically investigated. The flame structure is classified into three categories; premixed flame($=1)$, rich/lean premixed flame(${\alpha}=0.6$ and 0.8) and diffusion flame(${\alpha}=0$). NO formation/destruction mechanisms are assorted to thermal, reburn and Fenimore mechanisms. The temperature of unburned gas is arranged to 298 and 500 K to have access to the condition in a real internal combustion engine. The results show that all three NO formation/destruction reaction rates in the fuel rich flame zone could be decreased by EGR for rich/lean premixed flames, while those in the fuel lean flame zone are not significantly changed. Near the stagnation plane, however, only the thermal NO reaction rate is decreased. The contribution of reburn and Fenimore mechanisms for the net NO production becomes less significant as the premixedness of a flame increases. The larger amount of NO reduction with EGR is expected under the higher temperature and/or higher fuel/air premixedness conditions due to the increased contribution of the thermal mechanism. The role of Fenimore and reburn mechanisms could be important for rich premixed and diffusion flames; therefore, the effect of EGR on NO reduction could vary with fuel/air premixedness. The premixedness of a partially premixed flame changes the flame structure and could affect the NO production characteristics.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2009년도 추계학술대회 논문집
• /
• pp.218-221
• /
• 2009

Solid oxide fuel cells (SOFCs), as high-temperature fuel cells, have various advantages. In some merits of SOFCs, high temperature operation can lead to the capability for internal reforming, providing fuel flexibility. SOFCs can directly use CH4 and CO as fuels with sufficient steam feeds. However, hydrocarbons heavier than CH4, such as ethylene, ethane, and propane, induce carbon deposition on the Ni-based anodes of SOFCs. In the case of the ethylene steam reforming reaction on a Ni-based catalyst, the rate of carbon deposition is faster than among other hydrocarbons, even aromatics. In the reformates of heavy hydrocarbons (diesel, gasoline, kerosene and JP-8), the concentration of ethylene is usually higher than other low hydrocarbons such as methane, propane and butane. It is importatnt that ethylene in the reformate is removed for stlable operation of SOFCs. A new methodology, termed post-reforming was introduced for removing low hydrocarbons from the reformate gas stream. In this work, activity tests of some post-reforming catalysts, such as CGO-Ru, CGO-Ni, and CGO-Pt, are investigated. CGO-Pt catalyst is not good for removing ethylene due to low conversion of ethylene and low selectivity of ethylene dehydrogenation. The other hand, CGO-Ru and CGO-Ni catalysts show good ethylene conversion, and CGO-Ni catalyst shows the best reaction selectivity of ethylene dehydrogenation.

• Mass Spectrometry Letters
• /
• 제2권1호
• /
• pp.24-27
• /
• 2011

Hyperthermal ion/surface collisions of bromotoluene radical cations were studied using perfluorinated (F-SAM) and hydroxyl-terminated (OH-SAM) self-assembled monolayer surfaces in a tandem mass spectrometer with BEEQ geometry. The isomers were differentiated by ion abundance ratios taken from surface-induced dissociation (SID). The dissociation rate followed the order of ortho > meta > para isomers. The peak abundance ratio of m/z 51 to m/z 65 showed the best result to discern the isomers. A dissociation channel leading to tolylium ion was suggested to be responsible for the pronounced isomeric differences. The capability of SID to provide high-energy activation with narrow internal energy distribution may have channeled the reaction into the specific dissociation pathway, also facilitating small differences in reaction rates to be effective in the spectral time window of this experiment. All of the molecular ions experiencing reactive collisions with the F-SAM surface undergo transhalogenation, in which a fluorine atom on the surface replaces the bromine in the incoming ions. This reactive collision was dependent on the laboratory collision energy occurring in ca. 40.75 eV range.

• Tuberculosis and Respiratory Diseases
• /
• 제46권3호
• /
• pp.414-419
• /
• 1999

실리콘 액은 미용 및 성형수술에 널리 사용되어지고 실리콘에 의한 불법적인 의료행위가 증가함에 따라 국소적 부작용 뿐만 아니라 폐 색전증에 의한 급성 호흡곤란 증후군등의 치명적인 폐침범의 부작용을 일으킨다는 보고가 있으나 국내보고는 아직 없었다. 본 증례에서는 건강한 39세 젊은 여자 환자가 질벽에 실리콘액을 주사한 후에 발생한 폐 색전증을 동반한 급성 호흡곤란 증후군 1예을 경험하였기에 문헌고찰과 함께 보고하는 바이다.

• 한국전기전자재료학회논문지
• /
• 제11권11호
• /
• pp.1022-1026
• /
• 1998

The mutifilamentary $Nb_3$Sn wire containing 135 Nb filaments was manufactured by the internal tin method. The critical current density ($J_C$) in magnetic fields for the wires heat-treated at $660^{/circ}C$ and $700^{/circ}C$ were investigated. The Non-Cu $J_C$ and n-value of 0.82 mm$\phi$ $Nb_3$Sn wire heat-treated at $700^{/circ}C$ for 240 hours was approximately 450 A/$mm^2$ at 12T, 4.2K and 14, respectively. Also the $B_{C2}$ of $Nb_3$Sn wire extrapolated by Kramer plot was 27.2T. The wire heat-treated at $700^{/circ}C$ for 240 hours showed smaller residual tin concentration in the matrix and the larger area of $Nb_3$Sn layer as comparison with the wire heat-treated at $660^{/circ}C$.