• 한국산학기술학회논문지
• /
• 제13권6호
• /
• pp.2479-2483
• /
• 2012

본 논문은 휴대 및 이동이 가능한 개인용 소형 산소발생기 개발에 관한 것이다. 소형 산소발생기는 소형 진공펌프에 의해 진공흡착방식으로 작동된다. 각 구성품을 소형화와 경량화에 맞춰 구성하였으며 토출펌프 회전속도, 노즐 직경, 3-way 밸브 작동시간을 변화시키면서 산소농도와 유량을 최적화하였다. 노즐 직경 0.5mm에서 발생된 산소농도는 약 37%이며 유량은 $1{\ell}$/min이다. 노즐로부터 30cm 떨어진 위치에서 약 0.5%의 농도증가 효과가 나타났다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 1995년도 제8회 학술발표회 논문개요집
• /
• pp.21-21
• /
• 1995

• 한국진공학회지
• /
• 제11권1호
• /
• pp.28-34
• /
• 2002

진공 증착한 $Sb_{2-x}Bi_xTe_3$ 박막은 Bi 농도에 관계없이 비정질 형태로 성장되었고, XPS 분석 결과 증착 물질과 거의 유사한 조성을 가짐을 알 수 있었다. 또한 박막의 광학적, 전기적 특성을 설명하기 위해 여러 미세구조 파라미터들을 계산하였다. 한편, 박막 내 Bi 농도가 증가함에 따라 전기 비저항은 급격히 감소하였고, 특히 높은 Bi 농도(x=1.0)에서는 전도 특성이 p-type에서 n-type으로 변화되었다. 또한 $Sb_{2-x}Bi_xTe_3$ 박막의 굴절 지수 및 광학적 밴드 갭은 Bi 농도에 따라 증가하였다.

• 한국의류학회지
• /
• 제13권3호
• /
• pp.286-294
• /
• 1989

This Study has treated the effects of fiber, surfactants, temperature, surfactant concentration, pH, electrolyte, fatty acid contents and mechanical force on the removal of particulate soil from fabric, vacuum cleaner dirt was used as model particulate soil. The fabrics were soiled with mixture of vacuum cleaner dirt and fatty soil, and washed in Terg-O-tometer. The detergency was evaluated by measuring reflectance of a fabric before and after washing. The results were as follows. 1. The fiber type showed a different pattern of soil removal with surfactants. In general, particulate soil removal increased in the following order Acetate>PET. Nylon>Cotton. Particulate soil removal, which is affected by the surfactant type, increased in the following order NPE $(EO)_{10}\leqq$Soap>SLS>DBS>Tween 80. 2. The influence of temperature on the particulate soil removal was very complex because efficiency of removal was varied with surfactant and fiber types. The washing efficiency of NPE $(EO)_{10}$ was highest at around $40^{\circ}C\;and\;60^{\circ}C$ with cotton and PET but the washing efficiency of DBS was the highest at $60^{\circ}C$ with cotton, decreased monotonously with increasing temperature with PET 3. The detergency of particulate soil increased with increasing surfactant concentration at relatively low concentration and then levelled off above some optimum concentration. 4. The removal of particulate soil increased with increasing pH and mechanical force. 5. Effect of electrolyte on the particulate soil removal was depended on the concentration of the surfactant. At low concentration of surfactant, addition of electrolytes improved soil removal but above the some concentration no effect was observed. At high concentration of surfactant, Vie., $0.6\%$ , the maximum washing effect is reached without added electrolyte. These result indicate that added electrolyte only influence the adsorption of surfactant on the soil and fiber 6. Fatty acid content in the soil did not influence on particulate soil removal without regard to surfactants.

• 한국진공학회지
• /
• 제5권2호
• /
• pp.99-106
• /
• 1996

Two types of regularization method (singular system and HMP approaches) for generating depth-concentration profiles from angle-resolved XPS data were evaluated. Both approaches showed qualitatively similar results although they employed different numerical algorithms. The application of the regularization method to simulated data demonhstrates its excellent utility for the complex depth profile system . It includes the stable restoration of depth-concentration profiles from the data with considerable random error and the self choice of smoothing parameter that is imperative for the successful application of the regularization method. The self choice of smoothing parameter is based on generalized cross-validation method which lets the data themselves choose the optimal value of the parameter.

• 한국산업융합학회 논문집
• /
• 제25권5호
• /
• pp.835-842
• /
• 2022

In this study, the membrane degassing process of the sweep gas - vacuum combination type was proposed for ammonia wastewater treatment. The effect of pH, initial ammonia concentration and scale-up on ammonia degassing performance was investigated. As a result, as the pH and the initial ammonia concentration increased, the degassing permeate flux was improved. On the other hand, the ammonia mass transfer coefficient increased as the initial ammonia reduced, which seems to be due to the driving force of the sweep gas-vacuum combination type membrane degassing system proposed in this study. In addition, 80 mg NH₃/min of the ammonia degassing rate was achieved using a 6×28 inch size module. Better degassing performance is expected if consideration for maintaining vacuum pressure is involved in the scale-up design.

• 대한치과보철학회지
• /
• 제25권1호
• /
• pp.95-118
• /
• 1987

This study was undertaken to observe the elemental transition of Interface depending on different pretreatment methods, the number of filings, the kinds of porcelain powders and the various alloys in ceramo-metal restoration. The materials used in this study were Pors-on $4^{(R)}$ and Ceramco porcelain powder to compare the differences depending on the pretreatement methods and the number of firings. Ceramco porcelain powder and Vita porcelain powder were used to compare the differences of elemental transition depending on the porcelain powders. The $Parasil^{(R)},\;PGV^{(R)}$ and Pors-on $4^{(R)}$ as Pd-Ag alloy were used to compare the difference of elemental transition depending on the various alloys. The pretreatment methods were : no treatment, treatment under vacuum and air, treatment with 50 % hydrofluoric acid and double heat tretament. The number of firings were 3, 5 and 7 repeated firings All specimens were observed by SEM and concentration of elements were analyzed quantitatively with EPMA The results of this study were obtained as follows : 1. In the groups of air-treatment, concentration of Sn were the highest and widest. A high concentration of In were in the groups of vacuum and air treatment. 2. There were no significant differences in concentration of Sn between the group of vacuum, 5 minutes hydrofluoric acid and double heat treatment. (p>0.05) 3. As the period of time of hydrofluoric acid treatment increased, not only were the trace elements reduced but the main components such as Pd and Ag were also reduced. 4. Concentration of Sn and In increased and diffused with repeated firings but 5 repeated and 7 repeated firings groups had no significant differences. (p>0.05) 5. Sn were more concentrated in the group of Ceramco porcelaion powder than Vita porcelain powder. 6. The higher concentration of trace elements in the alloy, the more increasing concentration of Sn and In in the interface.

• 동의생리병리학회지
• /
• 제26권1호
• /
• pp.35-39
• /
• 2012

Sweet potato soju(SPS) has been made by vacuum distillation because sweet potato contains much fibrous materials which give high density to sweet potato mash. Generally, the SPS made by vacuum distillation has soft flavors and tastes. If the viscosity of sweet potato mash could be decreased by degradation enzyme, the process and production of SPS making by the method of vacuum distillation may be simplified and easier to distil the fermented sweet potato. Because the fibrous materials of sweet potato contains pectin with methoxyl group, methanol can be produced by fibrous degradation enzyme. For appling the fiber degradation enzymes to sweet potato mash for making SPS, the enzyme should be needed to degrade fibrous material without producing methanol. Special two fibrolytic enzymes are selected from 26 kind of commercial enzymes for the simplified and easier production of sweet potato soju by vacuum distillation, The selected enzyme A and X can degrade the fibrous material pectin of sweet potato without producing methanol. Although the different companies have produced the enzymes, same cellulase has been prepared from Trichoderma. reesei. The viscosity of sweet potato mash treated by the enzymes is decreased by 3 times with comparison to the viscosity of sweet potato mash of control group. The methanol concentration in the vacuum distilled SPS treated with the enzymes is 0.16%. The concentration is similar to that of commercially distilled SPS(0.15%). The result may suggest that the selected cellulases, A and X, can be used to make SPS by vacuum distillation.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
• /
• pp.378.1-378.1
• /
• 2014

In this study, we investigated that the resistance switching characteristics of Nb-doped HfO2 films with increasing Nb doping concentration. The Nb-doped HfO2 based ReRAM devices with a TiN/Nb-doped HfO2/Pt/Ti/SiO2 were fabricated on Si substrates. The Nb-doped HfO2 films were deposited by reactive dc magnetron co-sputtering at $300^{\circ}C$ and oxygen partial ratio of 60% (Ar: 16sccm, O2: 24sccm). Microstructure of Nb-doped HfO2 films and atomic concentration were investigated by XRD, TEM, and XPS, respectively. The Nb-doped HfO2 films showed set/reset resistance switching behavior at various Nb doping concentrations. The process voltage of forming/set is decreased and whereas the initial current level is increased in doped HfO2 films. However, the switching properties of Nb-doped HfO2 were changed above the specific doping concentration of Nb. The change of resistance switching behavior depending on doping concentration was discussed in terms of concentration of non-lattice oxygen and micro-structure of Nb-doped HfO2.

• Journal of Korean Vacuum Science & Technology
• /
• 제3권2호
• /
• pp.139-144
• /
• 1999

Hydrogen concentration depth profiles in homoepitaxial Si(001) films grown from hyper-thermal Si beams generated by ultrahigh vacuum (UHV) ion-beam sputtering have been measured by nuclear reaction analyses as a function of film growth temperature and deposition rate. Bulk H concentrations CH in the crystalline Si layers were found tio be below detection limits, 1${\times}$1019cm-3, with no indication of significant H surface segregation at the crystalline/amorphous interface region. This is quite different than the case for growth by molecular-beam epitaxy (MBE) where strong surface segregation was observed for similar deposition conditions with average CH values of 1${\times}$1020cm-3 in the amorphous overlayer. The markedly decreased H concentrations in the present experiments are due primarily to hydrogen desorption by incident hyperthermal Si atoms. Reduced H surface coverages during growth combined with collisionally-induced filling of interisland trenches and enhanced interlayer mass transport provide an increase in critical epitaxial thicknesses by up to an order of magnitude over previous MBE results.