• Title/Summary/Keyword: 수치계산

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Analysis of CO2 Emission Depending on Hydrogen Production Methods in Korea (국내 수소 생산에 따른 CO2 발생량 분석)

  • Han, Ja-Ryoung;Park, Jinmo;Kim, Yohan;Lee, Young Chul;Kim, Hyoung Sik
    • Journal of the Korean Institute of Gas
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    • v.23 no.2
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    • pp.1-8
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    • 2019
  • Because of environmental pollution problem, interests in hydrogen energy has been concentrating sharply. Especially in Korea, the market related with fuel cell vehicles and hydrogen refueling stations is increasing actively under the government-led. However, the actual contributions to environmental improvement effect of hydrogen energy is required to be evaluated with representing reality. In this sense, lots of conventional analyzing tools have some limitations to adapt in Korea's situation directly. It is caused by the differences of raw energy market between the US and Korea. That is, most of analytic tools are developed by representing energy market of the US, where can produce variety of raw feed energy sources. Therefore, in this paper, we propose mass balance based numerical analyzing method, which is suitable for the actual hydrogen production process in Korea for exact evaluation of $CO_2$ emission amount in this country. Using proposed method, we has demonstrated reformed hydrogen from natural gas, LPG and naphtha, electrolysis-based hydrogen, and COG-based hydrogen. Furthermore, with the comparison of GREET program analysis results, robustness of numerical analysis method is demonstrated.

Utility of B-type Natriuretic Peptide in Patients with Acute Respiratory Distress Syndrome (급성호흡곤란증후군 환자에 있어서 B-type Natriuretic Peptide의 유용성)

  • Rhee, Chin Kook;Joo, Young Bin;Kim, Seok Chan;Park, Sung Hak;Lee, Sook Young;Koh, Yoon Seok;Kim, Young Kyoon
    • Tuberculosis and Respiratory Diseases
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    • v.62 no.5
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    • pp.389-397
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    • 2007
  • Background B-type natriuretic peptide (BNP) has been shown to be strong mortality predictors in a wide variety of cardiovascular syndromes. Little is known about BNP in patients with acute respiratory distress syndrome (ARDS). We studied whether BNP can predict mortality in patients with ARDS. Method Echocardiographic study was done to all patients with ARDS, and we excluded patient with low ejection fraction (less than 50%) or showing any features of diastolic dysfunction. 47 patients were enrolled between December, 2003 and February, 2006. Parameters including BNP were obtained within 24h hours at the time of enrollment. Result Mean BNP concentrations and APACHE II scores differed between the survivors and nonsurvivors (BNP, $219.5{\pm}57.7pg/mL$ vs $492.3{\pm}88.8pg/mL$; p=0.013, APACHE II score, $17.4{\pm}1.6$ vs $23.1{\pm}1.3$, p=0.009, respectively). With the use of the threshold value for BNP of 585 pg/mL, the specificity for the prediction of mortality was 94%. The threshold value for APACHE II of 15.5 showed sensitivity of 87%. 'APACHE II + $11{\times}logBNP$' showed sensitivity 63%, and specificity 82%, using threshold value for 46.14. Conclusion BNP concentrations and APCHE II scores were more elevated in nonsurvivors than survivors in patients with ARDS who have normal ejection fraction. BNP can predict mortality. Further study should be done.

Crosshole EM 2.5D Modeling by the Extended Born Approximation (확장된 Born 근사에 의한 시추공간 전자탐사 2.5차원 모델링)

  • Cho, In-Ky;Suh, Jung-Hee
    • Geophysics and Geophysical Exploration
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    • v.1 no.2
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    • pp.127-135
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    • 1998
  • The Born approximation is widely used for solving the complex scattering problems in electromagnetics. Approximating total internal electric field by the background field is reasonable for small material contrasts as long as scatterer is not too large and the frequency is not too high. However in many geophysical applications, moderate and high conductivity contrasts cause both real and imaginary part of internal electric field to differ greatly from background. In the extended Born approximation, which can improve the accuracy of Born approximation dramatically, the total electric field in the integral over the scattering volume is approximated by the background electric field projected to a depolarization tensor. The finite difference and elements methods are usually used in EM scattering problems with a 2D model and a 3D source, due to their capability for simulating complex subsurface conductivity distributions. The price paid for a 3D source is that many wavenumber domain solutions and their inverse Fourier transform must be computed. In these differential equation methods, all the area including homogeneous region should be discretized, which increases the number of nodes and matrix size. Therefore, the differential equation methods need a lot of computing time and large memory. In this study, EM modeling program for a 2D model and a 3D source is developed, which is based on the extended Born approximation. The solution is very fast and stable. Using the program, crosshole EM responses with a vertical magnetic dipole source are obtained and the results are compared with those of 3D integral equation solutions. The agreement between the integral equation solution and extended Born approximation is remarkable within the entire frequency range, but degrades with the increase of conductivity contrast between anomalous body and background medium. The extended Born approximation is accurate in the case conductivity contrast is lower than 1:10. Therefore, the location and conductivity of the anomalous body can be estimated effectively by the extended Born approximation although the quantitative estimate of conductivity is difficult for the case conductivity contrast is too high.

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Effect of submerged culture of Ceriporia lacerata mycelium on GLUT4 protein in db/db mouse (db/db 마우스에서 Ceriporia lacerata 균사체 배양액이 GLUT4 발현에 미치는 영향)

  • Shin, Eun Ji;Kim, Ji-Eun;Kim, Ji-Hye;Park, Yong Man;Yoon, Sung Kyoon;Jang, Byeong-Churl;Lee, Sam-Pin;Kim, Byoung-Cheon
    • Korean Journal of Food Preservation
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    • v.22 no.6
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    • pp.893-900
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    • 2015
  • In this study, we evaluated the antidiabetic effect of a submerged culture of Ceriporia lacerata mycelium (CL01) on hematological indices, as well as protein and mRNA expression of the insulin-signaling pathway, in db/db mice. After CL01 was administrated for 4 weeks, blood glucose levels decreased consistently, and plasma insulin and c-peptide levels each decreased by roughly 55.8%, 40% of those in the negative control (p<0.05). With regard to HOMA-IR, an insulin resistance index, insulin resistance of the CL01-fed group improved over that of the negative control group by about 62% (p<0.05). In addition, we demonstrated that the protein expression levels of pIR, pAkt, pAMPK, and GLUT4 and the mRNA expression levels of Akt2, IRS1, and GLUT4 in the muscle cells of db/db mice increased in the CL01-fed group compared to the corresponding levels in the control group. These results demonstrate that CL01 affects glucose metabolism, upregulates protein and gene expression in the insulin-signaling pathway, and decreases blood glucose levels effectively by improving insulin sensitivity. More than 90% of those who suffer from type 2 diabetes are more likely to suffer from hyperinsulinemia, hypertension, obesity, and other comorbidities because of insulin resistance. Therefore, it is possible that CL01 intake could be used as a fundamental treatment for type 2 diabetes by lowering insulin resistance, and these results may prove be useful as basic evidence for further research into the mechanisms of a cure for type 2 diabetes.

$CO_2$ Transport for CCS Application in Republic of Korea (이산화탄소 포집 및 저장 실용화를 위한 대한민국에서의 이산화탄소 수송)

  • Huh, Cheol;Kang, Seong-Gil;Cho, Mang-Ik
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.13 no.1
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    • pp.18-29
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    • 2010
  • Offshore subsurface storage of $CO_2$ is regarded as one of the most promising options to response severe climate change. Marine geological storage of $CO_2$ is to capture $CO_2$ from major point sources, to transport to the storage sites and to store $CO_2$ into the offshore subsurface geological structure such as the depleted gas reservoir and deep sea saline aquifer. Since 2005, we have developed relevant technologies for marine geological storage of $CO_2$. Those technologies include possible storage site surveys and basic designs for $CO_2$ transport and storage processes. To design a reliable $CO_2$ marine geological storage system, we devised a hypothetical scenario and used a numerical simulation tool to study its detailed processes. The process of transport $CO_2$ from the onshore capture sites to the offshore storage sites can be simulated with a thermodynamic equation of state. Before going to main calculation of process design, we compared and analyzed the relevant equation of states. To evaluate the predictive accuracies of the examined equation of states, we compare the results of numerical calculations with experimental reference data. Up to now, process design for this $CO_2$ marine geological storage has been carried out mainly on pure $CO_2$. Unfortunately the captured $CO_2$ mixture contains many impurities such as $N_2$, $O_2$, Ar, $H_{2}O$, $SO_{\chi}$, $H_{2}S$. A small amount of impurities can change the thermodynamic properties and then significantly affect the compression, purification and transport processes. This paper analyzes the major design parameters that are useful for constructing onshore and offshore $CO_2$ transport systems. On the basis of a parametric study of the hypothetical scenario, we suggest relevant variation ranges for the design parameters, particularly the flow rate, diameter, temperature, and pressure.

Maximum Value Calculation of High Dose Radioiodine Therapy Room (고용량 방사성옥소 치료 병실의 최대치 산출)

  • Lee, Kyung-Jae;Cho, Hyun-Duck;Ko, Kil-Man;Park, Young-Jae;Lee, In-Won
    • The Korean Journal of Nuclear Medicine Technology
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    • v.14 no.1
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    • pp.28-34
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    • 2010
  • Purpose: According to increment of thyroid cancer recently, patients of high dose radioiodine therapy were accumulated. Taking into consideration the acceptance capability in the current facility, this study is to calculate the maximum value of high dose radioiodine therapy in patients for treatment. Materials and Methods: The amount and radioactivity of waste water discharged from high dose radioiodine therapy in patients admitted at present hospital as well as the radiation density of the air released into the atmosphere from the high dose radioiodine therapy ward were measured. When the calculated waste water's radiation and its density in the released air satisfies the standard (management standard for discharge into water supply 30 Bq/L, management standard for release into air 3 $Bq/m^3$) set by the Ministry of Education, Science and Technology, the maximum value of treatable high dose radioiodine therapy in patients was calculated. Results: When we calculated in a conservative view, the average density of radiation of waste water discharged from treating high dose radioiodine therapy one patient was 8 MBq/L and after 117 days of diminution in the water-purifier tank, it was 29.5 Bq/L. Also, the average density of radiation of waste water discharged from treating high dose radioiodine therapy two patients was 16 MBq/L and after 70 days of diminution in the water-purifier tank, it was 29.7 Bq/L. Under the same conditions, the density of radiation released into air through RI Ventilation Filter from the radioiodine therapy ward was 0.38 $Bq/m^3$. Conclusion: The maximum value of high dose radioiodine therapy in patients that can be treated within the acceptance capability was calculated and applied to the current facility, and if double rooms are managed by improving the ward structure, it would be possible to reduce the accumulated treatment waiting period for radioiodine therapy in patients.

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