• Transactions of the Korean hydrogen and new energy society
• /
• v.27 no.6
• /
• pp.628-635
• /
• 2016

Natural gas reformed hydrogen is used as a fuel of fuel cell vehicle, PSA process is used for the purification of reformed hydrogen. In this study, the performance of CO adsorbent in PSA process was evaluated. Zeolite adsorbents used in the commercial PSA process is used. The physical and chemical properties of adsorbents were characterized using BET apparatus, XRD, and FE-SEM. The breakthrough apparatus modified from GC was used for the CO breakthrough experiment, the quantitative analysis of CO adsorption capacity was performed using CO breakthrough curve. Zeolite 10X and 13X showed superior CO adsorption capacity than activated alumina. The CO adsorption capacity of zeolite 10X is more than twice of zeolite 13X even the BET surface area is low. It seems that the presence of $Ca^{2+}$ cation in zeolite 10X is beneficial to the adsorption of CO.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.13
• /
• pp.5365-5370
• /
• 2015

Background: Combining risk factors for prostate cancer into a predictive tool may improve the detection of prostate cancer while decreasing the number of benign biopsies. We compare one such tool, age multiplied by prostate volume divided by total serum PSA (PSA-AV) with PSA density and detection of primary malignant circulating prostate cells (CPCs) in a Chilean prostate cancer screening program. The objectives were not only to determine the predictive values of each, but to determine the number of clinically significant cancers that would have been detected or missed. Materials and Methods: A prospective study was conducted of all men undergoing 12 core ultrasound guided prostate biopsy for suspicion of cancer attending the Hospital DIPRECA and Hospital de Carabineros de Chile. Total serum PSA was registered, prostate volumecalculated at the moment of biopsy, and an 8ml blood simple taken immediately before the biopsy procedure. Mononuclear cells were obtained from the blood simple using differential gel centrifugation and CPCs identified using immunocytchemistry with anti-PSA and anti-P504S. Biopsy results were classed as positive or negative for cancer and if positive the Gleason score, number of positive cores and percent infiltration recorded. Results: A total of 664 men participated, of whom 234 (35.2%) had cancer detected. They were older, had higher mean PSA, PSA density and lower PSA-AV. Detection of CPCs had high predictive score, sensitivity, sensibility and positive and negative predictive values, PSA-AV was not significantly different from PSA density in this population. The use of CPC detection avoided more biopsies and missed fewer significant cancers.Conclusions: In this screening population the use of CPC detection predicted the presence of clinically significant prostate cancer better than the other parameters. The high negative predictive value would allow men CPC negative to avoid biopsy but remain in follow up. The formula PSA-AV did not add to the predictive performance using PSA density.

• Transactions of the Korean hydrogen and new energy society
• /
• v.17 no.1
• /
• pp.8-20
• /
• 2006

For large scale separation hydrogen from different mixing ratio(60/40 and 80/20 vol.%) of hydrogen and methane $1Nm^3/hr$ and $4Nm^3/hr$ 2bed-6step pressure swing adsorption(PSA) process was used, respectively. The effects of the feed gas pressure, adsorption time, the feed flow rate and the P/F(purge to feed) ratio on the process performance were evaluated. In the $1Nm^3/hr$ PSA results, 11 atm adsorption pressure and 0.10 P/F ratio might be optimal values to obtain more than 75 % recovery and 99 % purity hydrogen in these processing. The optimum feed flowrate was 22 LPM and 17 LPM in the ratio 60/40 and 80/20, respectively. In the $4Nm^3/hr$ PSA results, 10 atm adsorption pressure might be simulated values to obtain more than 80 % recovery and 99 % purity hydrogen in these processing.

• Nuclear Engineering and Technology
• /
• v.30 no.1
• /
• pp.58-74
• /
• 1998

A PC window-based computer code, CONPAS (CONtainment Performance Analysis System), has been developed to integrate the numerical, graphical, and results-operation aspects of Level 2 probabilistic safety assessments (PSA) for nuclear power plants automatically. As a main logic for accident progression analysis, it employs a concept of the small containment phenomenological event tree (CPET) helpful to trace out visually individual accident progressions and of the detailed supporting event tree (DSET) for its detailed quantification. For the integrated analysis of Level 2 PSA, the code utilizes five distinct, but closely related modules. Its computational feasibility to real PSAs has been assessed through an application to the UCN 3&4 full scope Level 2 PSA. Compared with other existing computer codes for Level 2 PSA, the CONPAS code provides several advanced features: (1) systematic uncertainty analysis / importance analysis / sensitivity analysis, (2) table / graphical display & print, (3) employment of the recent Level 2 PSA technologies, and (4) highly effective user interface. The main purpose of this paper is to introduce the key features of CONPAS code and results of its feasibility study.

• Journal of the Korean Society of Safety
• /
• v.28 no.3
• /
• pp.123-128
• /
• 2013

The Advanced Power Reactor Plus(APR+), which is a GEN III+ reactor based on the APR1400, is being developed in Korea. In order to enhance the safety of the APR+, a passive auxiliary feedwater system(PAFS) has been adopted in the APR+. The PAFS replaces the conventional active auxiliary feedwater system(AFWS) by introducing a natural driving force mechanism while maintaining the system function of cooling the primary side and removing the decay heat. As the PAFS completely replaces the conventional AFWS, it is required to verify the cooling capacity of PAFS for the core damage frequency(CDF) evaluation. For this reason, this paper discusses the cooling performance of the PAFS during transient accidents. The test case and scenarios were picked from the result of the sensitivity analysis in APR+ Probabilistic Safety Assessment(PSA). The analysis was performed by the best estimate thermal-hydraulic code, RELAP5/.MOD3.3. This study shows that the plant maintains the stable state without the core damages under the given test scenarios. The results of PSA considering this analysis' results shows that the CDF values are decreased. The analysis results can be used for more realistic and accurate performance of a PSA.

• Journal of the Korean Society of Safety
• /
• v.12 no.4
• /
• pp.143-152
• /
• 1997

Probabilistic Safety Assessment(PSA) is an engineering analysis of the possible contributors to the risk from a nuclear power plant. It consist of three phases named as Level 1, 2 and 3. Level 1 PSA mainly focused in this paper is the phase of system analysis which includes the development of accident scenarios and the frequency estimation of each scenario. It covers also the system reliability analysis, component data analysis, and human reliability analysis. PSA have become a standard tool in safety evaluation of nuclear power plants. The main benefit of PSA is to provide insights into plant design, performance and environmental impacts, including the identification of dominant risk contributors and the comparison of options for reducing risk.

• Journal of Adhesion and Interface
• /
• v.2 no.1
• /
• pp.31-43
• /
• 2001

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.2 no.2
• /
• pp.249-258
• /
• 1998

In land mobile communication, very extensive studies on pilot symbol assisted modulation (PSAM) have been made on fading compensation. This paper analyzes the effect of power amplifier nonlinearity on PSA-QAM with maximal ratio combining space diversity. In practical PSAM, information on fading is obtained through interpolation of the pilot symbols. We employed the interpolation filter which could minimize the average power of error and analyzed effects on the system performance of the number of filter taps, period of the pilot symbol frame, and the Doppler frequency. Nonlinear power amplifiers of class AB, B, and C were incorporated in the system models and their AM/AM and AM/PM characteristics were taken into account in the performance analysis. We showed the performance variations according to the types of the nonlinear power amplifiers in the AWGN and Rayleigh fading channels using nonlinear compensation technique, Cartesian Feedback Loop (CFB).

• Journal of the Korean Society of Safety
• /
• v.15 no.2
• /
• pp.126-135
• /
• 2000

Probabilistic Safety Assessment (PSA) is an engineering analysis method to identify possible contributors to the risk from a nuclear power plant and now it has become a standard tool in safety evaluation of nuclear power plants. PSA consists of three phases named as Level 1, 2 and 3. Level 2 PSA, mainly focused in this paper, uses a step-wise approach. At first, plant damage states (PDSs) are defined from the Level 1 PSA results and they are quantified. Containment event tree (CET) is then constructed considering the physico-chemical phenomena in the containment. The quantification of CET can be assisted by a decomposition event tree (DET). Finally, source terms are quantitatively characterized by the containment failure mode. As the main benefit of PSA is to provide insights into plant design, performance and environmental impacts, including the identification of the dominant risk contributors and the comparison of options for reducing risk, this technique is expected to be applied to the industrial safety area.

• Journal of Adhesion and Interface
• /
• v.10 no.3
• /
• pp.127-133
• /
• 2009

Acrylic pressure sensitive adhesives (PSAs) are used in various field of high-technology industries such as semiconductor, display, mobile, automobile, and so on. Because of they have high durabilities and can be easily introduced functional groups in their molecular structures. PSA perfomances has an effect on their applications in industry process operation, reliability of final products. In this study, PSA performances as a function of fim thickness which is one of the impact factors effects on PSA performances will be investigated using combinatorial methods. Acrylic PSAs are synthesized using 2-ethylhexyl acrylate and acrylic acid. Thickness-gradient of acrylic PSA sample is made by a micro applicator. We compare general coating method with thickness-gradient coating method and evaluate the reappearance of combinatorial methods compared with existing coating method. Thickness-gradient of acrylic PSA sample shows rough and broad data tendency.