• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.432-435
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• 1996

The performance of one-column isothermal PSA process is assessed by dynamic simulator, gPROMS. The four-step and five-step processes are compared. A five-step process is employed in order to show the effect of the addtional cocurrent depressurization step on the four-step PSA process. Two processes parameters, purity and recovery of SO$_{2}$ are used for the performance comparison. The results of dynamic simulation show that four-step process is superior to five-step process in recovery, but not in purity.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1350-1354
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• 2007

As the importance of low power design is emphasized, power consumption became one of the standards that represent the performance of the system. The purpose of this study is to decide design variable that minimize power consumption for the oxygen concentrator in two bed-one compressor 8 step PSA process that has above 90% purity at 3lpm by using given constants and selected parameters. Setting selected parameters as cycle time and equalization time, optimization for PSA process in the oxygen concentrator is progressed. For this, we need to know the features and basic principals of PSA process and to deduce objective function of performance analysis. Validations for objective function and lots of experiments are needed too. By using the characteristic curve of the compressor and the pressure curve of the process for 1 cycle, objective function was set. After theoretical 2 dimensional optimized paths was obtained. And then, by experiment, theoretical optimized path was verified.

• Applied Chemistry for Engineering
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• v.7 no.4
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• pp.653-660
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• 1996

For oxygen PSA process development, adsorbed amount of oxygen and nitrogen on various adsorbents were measured corresponding Langmuir isotherm parameters were measured. A reasonable adsorbent for oxygen process was selected based on the effective adsorbed amount. The PSA process consists of adsorption, desorption, pressurization, purging and pressure equilization steps. Adsorption pressure was about 2 atm and desorption pressure was between 120 torr to 400torr. Cycle time of 2-bed PSA process was 80 seconds and that of 3-bed oxygen PSA process was 180 seconds. In order to compare and analyze operation characteristics and economic feasibilities of 2-bed and 3-bed oxygen PSA processes, productivity, oxygen concentration and recovery were compared and the effect of purge and pressurization steps on the performance of PSA processes were analyzed. For the commercial scale oxygen PSA process, capital and electricity cost were estimated. In the range of $O_2$ production less than $700Nm^3/hr$, the 2-bed process is conformed more feasible in economic view point.

• Biomedical Science Letters
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• v.3 no.2
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• pp.107-114
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• 1997

Recent reports indicate that the clinical usefulness of prostate specific antigen (PSA), particulary in the differentiation of benign prostate hyperplasia from prostate cancer, can be improved by measuring the amount of free PSA in serum. Measuring free PSA is especially useful in attempts to improve diagnositc performance of PSA in the diagnostic gray zone of total PSA. The objective of this study was to develop free PSA assay kit using sandwich microplate enzyme immunoassay format. We chose a test format with polyclonal anti-PSA antibodies coated on the wells and monoclonal anti-free PSA antibodies for quantification to gain higher test sensitivity. We adpoted 10 uL of specimen and 2 hours of first incubation time with detecting antibody for free PSA EIA format using microplate. The within-day and between-day precision (%CV) in the high and low concentration ranges were below 4%. The correlation coefficient between in-house free PSA assay and commercial assay kit was r=0.9965 (slope=0.0984, y intercept=0.0173, N=27). No hook effect was found by 40 ng/mL and correlation coefficient (r) value of the fitted linear regression was over 0.995. The recovery tests were in the range of 98.9∼104.1％ for free PSA. In conclusion, in-house free PSA enzyme immune assay is cost effective, simple and rapid and could be useful for the prognosis after theraphy as well as for the differential diagnosis between prostate cancer and benign prostate hyperplasia.

• Journal of Adhesion and Interface
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• v.9 no.3
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• pp.27-33
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• 2008

A series of aluminum acetylacetonate (AlACA) belonging in inorganic chelate calculating with the ratio of -COOH mole in PSA (0, 0.25, 0.5, 0.75, 1) and a series of PSA with different acrylic acid contents (3 wt%, 7 wt%, 10 wt%) were blended and measured gel contents, probe tack, peel strength, SAFT. With the increasing of aluminum acetylacetonate contents, the network structure was formed and gel contents were increased. Probe tack fibrillation and peel strength were decreased following the addition of aluminum acetylacetonate. SAFT were significantly changed with the change of acrylic acid contents in PSA. From these results, aluminum acetylacetonate could be used in the range of which would not change the performance a lot, and cure the PSA.

• Clean Technology
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• v.10 no.2
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• pp.101-109
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• 2004

PSA and VSA processes have been used broadly to produce oxygen from ambient air in midium- or small-sized plants. PSA and VSA processes are the separation methods which use difference of amount adsorbed as pressure is changed periodically, but they have the differences in pressurization and regeneration. In this study, the performance of 6-step PSA process was compared with that of 5-step VSA process with respect to purity and recovery. In addition, the effects of each step (pressurization step, adsorption step, and pressure equalization step) on purity and recovery were investigated. As a result, the VSA process using zeolite 10X showed better performance than the zeolite 5A PSA and zeolite 13X VSA process in comparison with purity, recovery and productivity. And it was enough to apply the vacuum pressure of 200 torr for the VSA, which produced over 90% oxygen with 70% recovery.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.1
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• pp.99-110
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• 2004

In order to investigate the performance of carbon dioxide PSA over zeolite adsorbent, the present study showed results of isotherm measurement, cyclic operation of 3-bed apparatus, and the corresponding numerical simulation. The experiment data of bed temperature, purity, recovery were matched well with that of numerical simulation. Purity of both gas and adsorbent phase increased rapidly with rinse rate but the degree of increase was retarded for large rinse rate The total amount of adsorbed increased only 10% even if rinse rate was enlarged to 4 times. Optimal rinse rate was 7N㎥/hr in this study. The heating rinse led to augments in recovery and productivity, possibly thanks to ease of description resulting from increased volumetric rinse rate and temperature rise in the column.

• Journal of Information Processing Systems
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• v.16 no.2
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• pp.478-493
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• 2020

We designed a new meta-heuristic algorithm named Photon Search Algorithm (PSA) in this paper, which is motivated by photon properties in the field of physics. The physical knowledge involved in this paper includes three main concepts: Principle of Constancy of Light Velocity, Uncertainty Principle and Pauli Exclusion Principle. Based on these physical knowledges, we developed mathematical formulations and models of the proposed algorithm. Moreover, in order to confirm the convergence capability of the algorithm proposed, we compared it with 7 unimodal benchmark functions and 23 multimodal benchmark functions. Experimental results indicate that PSA has better global convergence and higher searching efficiency. Although the performance of the algorithm in solving the optimal solution of certain functions is slightly inferior to that of the existing heuristic algorithm, it is better than the existing algorithm in solving most functions. On balance, PSA has relatively better convergence performance than the existing metaheuristic algorithms.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.609-612
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• 2007

The HDD (hard disk drive) using Load/Unload (L/UL) technology includes the benefits which are increased areal density, reduced power consumption and improved shock resistance than those of contact-start-stop (CSS). Dynamic L/UL has been widely used in portable hard disk drive and will become the key technology for developing the small form factor hard disk drive. The main design objectives of the L/UL mechanisms are no slider-disk contact or no media damage even with contact during L/UL, and a smooth and short unloading process. In this paper, we focus on lift-off force, pitch static attitude (PSA), roll static attitude (RSA) and dimple point. The "lift-off" force, defined as the minimum air bearing force, is another very important indicator of unloading performance. A large amplitude of lift-off force increases the ramp force, the unloading time, the slider oscillation and contact-possibility. PSA and RSA are also very important parameters in L/UL system and stability of slider is mainly determined by PSA and RSA. Dimple point by PSA and RSA is also important indicator. Therefore we find the optimal dimple point of SFF HDD suspension for improving the unloading performance.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.206.1-206.1
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• 2010

폐기물 등을 열분해 가스화한 합성가스로부터 효과적으로 고순도의 수소를 회수하기 위하여 WGS(수성가스전환반응) 및 $CO_2$ 회수 PSA 공정을 적용하였다. 벤치스케일 열교환형 WGS반응기를 개발하여 기존 단열방식에 비하여 단순화한 반응시스템을 구축하였으며 출구 CO농도 4%대를 달성하였다. 또한 3베드로 구성된 벤치스케일의 $CO_2$ PSA운전을 수행한 결과, 2.5barg 흡착 및 진공재생단계를 적용하여 회수되는 $CO_2$의 농도가 95%이상, 회수율 80%이상을 기록하는 효율적인 $CO_2$ 회수공정을 개발하였다. 한편, 흡탈착 모사프로그램인 ADSIM을 통해서도 실험과 비교적 일치한 결과를 얻을 수 있었는데 향후 스케일업 설계자료 확보시 유용할 것으로 판단되었다.