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Korea's social dynamics towards power supply and air pollution caused by electric vehicle diffusion
Ahn, Sang-Jin,Kim, Leo,Kwon, Okyu ELSEVIER 2018 Journal of Cleaner Production Vol.205 No.-
<P><B>Abstract</B></P> <P>Korea has the highest air pollution among the Organization for Economic Co-operation and Development (OECD) countries. Since the recent environmental analysis () reported the feasibility of replacing taxis with electric vehicles (EVs) in metropolitan cities from a ‘tank-to-wheel’ emission perspective, various stakeholders have attempted to reduce air pollution by activating the EV market in Korea in accordance with international trends. Nevertheless, no holistic study has yet been published on the nationwide changes in air quality caused by EV diffusion from the perspective of ‘well-to-wheel’ emissions. This paper presents the results of estimating the stability of the electric power supply and fine particulate matter emissions in some cases, and the results of examining the structure of public discourse using big social media data. From the findings of our study, we made the following conclusions: (1) If the market share of EVs exceeds 12.5% before 2030 in Korea's domestic market, the supply and demand of stable energy will be threatened. (2) Under traditional energy mix conditions, the popularization of EVs may slightly reduce air pollution over metropolitan roads, but drastically increase air pollution near power plants that utilize fossil fuels. (3) Social media discussions show that the public is neither concerned about EVs being possible sources of pollutants, nor about potential instabilities in the energy market. (4) To obtain a socially acceptable energy mix, energy policy decision makers can select emission-free energy sources, such as nuclear power and renewable energy, depending on their priorities and based on power demand management to suppress excessive electrification.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The rapid expanding electric car market can threaten the supply and demand of stable enegy. </LI> <LI> The effects of improving the air quality by electric cars differ depending on the region. </LI> <LI> The public does not concern about electricity supply as well as air pollution by electric cars. </LI> <LI> Policy makers can choose either nuclear power or renewable energy depending on their priorities. </LI> </UL> </P>
Life-cycle Cost Analysis of a TPSM Applied Continuous Composite Girder Bridge
( Sang Hyo Kim ),( Jun Hwan Kim ),( Chi Young Jung ),( Jin Hee Ahn ) 한국강구조학회 2010 International Journal of Steel Structures Vol.10 No.2
Transverse cracks in composite girder bridges are repeatedly reported because the tensile stresses in the concrete deck induced by the negative bending moment at the intermediate supports of continuous composite girder bridges. The occurred transverse cracks rapidly deteriorate the concrete deck, giving rise to frequent need for maintenance work. Prestressing methods are usually utilized in this kind of situation for the concrete structures, however no effective and feasible method has yet been proposed for steel-concrete composite structures. A new type of prestressing method entitled Thermal prestressing method (TPSM) has been proposed for innovative construction of continuous composite girder bridges, as effective prestressing method to prevent the occurrence of the tensile transverse crack of the concrete deck at the negative bending moment regions. In this study, the methodology for the economic analysis of TPSM applied bridges and case studies are introduced based on the lifecycle cost, considering initial construction cost and maintenance cost, to demonstrate the financial viability of the TPSM applied bridges compared to conventional continuous composite girder bridges.
Sang-Yong Son,Chang Min Lee,Ju-Hee Lee,Sang-Hoon Ahn,Jin Won Kim,Kuhn-Uk Lee,Do Joong Park,Hyung-Ho Kim 대한외과학회 2013 Annals of Surgical Treatment and Research(ASRT) Vol.84 No.5
Prophylactic para-aortic lymphadenectomy is not recommended in curable advanced gastric cancer. However, there are few reports on therapeutic para-aortic lymphadenectomy after palliative chemotherapy in far advanced gastric cancer. We report three cases of laparoscopy-assisted gastrectomy with para-aortic lymphadenectomy after palliative chemotherapy for the first time in Korea. Three gastric cancer patients with isolated para-aortic lymph node (PAN) metastasis showed partial response to capecitabine-based chemotherapy, and laparoscopy-assisted gastrectomy with para-aortic lymphadenectomy was performed with curative intent. The mean total operation time was 365 minutes (range, 310 to 415 minutes), and the mean estimated blood loss was 158 mL (range, 125 to 200 mL). The mean number of retrieved PAN was 9 (range, 8 to 11), and all pathologic results showed no metastasis of para-aortic region. All patients recovered and were discharged without any significant complications.
( Sang Hoon Ahn ),( Won Kim ),( Young Kul Jung ),( Jin Mo Yang ),( Jae Young Jang ),( Yong Oh Kweon ),( Yong Kyun Cho ),( Yoon Jun Kim ),( Gun Young Hong ),( Dong Joon Kim ),( Soon Ho Um ),( Joo Hyun 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1
Aims: Besifovir is an acyclic nucleotide phosphonate known to be effective in hepatitis B virus (HBV) DNA suppression for both treatment- naïve and lamivudine-resistant chronic HBV infection in preliminary studies. We assessed the safety and efficacy of besifovir comparing with tenofovir in treatment-naïve chronic hepatitis B patients. Methods: A total of 187 patients were randomly received besifovir dipivoxil 150mg or tenofovir disoproxil fumarate 300mg. Eligible subjects were patients with chronic HBV infection. We measured the proportion of patients who had HBV DNA less than 69 IU/mL at week 48 as the primary efficacy endpoint. Key secondary endpoints were histological response (i.e., a reduction in the Knodell necroinflammation score of 2 or more points without worsening fibrosis), serum HBV DNA reduction, and liver function tests. Also, bone mineral density (BMD) and renal parameters were evaluated. Results: The proportion of patients who achieved primary endpoint of HBV DNA (< 69 IU/mL) at week 48 were 85.33% and 88.75% among those who received besifovir and tenofovir, respectively. Besifovir was shown to be non-inferior to tenofovir (lower limit of 95% CI for the treatment difference =-0.14). Histological improvement of 29 patients who underwent liver biopsy was evaluated, and we found that significantly more patients treated with besifovir had improved histological response than those treated with tenofovir (77.78% vs. 36.36%, p=0.0482). There was no difference in intrahepatic cccDNA reduction between the two groups (p=0.35). None of the patients had resistant to mutations or increase in serum creatinine >0.5mg/dL from baseline. Patients who received besifovir had smaller decrease in BMD during 48 weeks than that of tenofovir (besifovir -0.02±0.44, tenofovir -0.10±0.86, p=0.0248). There was no adverse drug reaction leading the patients to withdrawal. Conclusions: This phase 3 study demonstrated that besifovir had comparable efficacy and safety profile to tenofovir in the treatment of treatment-naïve chronic hepatitis B patients. Besifovir showed better profile than tenofovir in both histological response and bone loss. An open-label extension study is ongoing with besifovir to investigate long-term efficacy and safety.
VOCs Sensing Property of Graphene Oxide Thin Film by Reduction Rate
Ahn, Ho Sang,Park, Hye Jin,Oh, Ju Hyun,Joo, Jin Chul,Kim, Dong Joo Trans Tech Publications, Ltd. 2013 Applied Mechanics and Materials Vol. No.
<P>We demonstrate a combinatorial graphene oxide (GO) and reduced graphene oxide (rGO) thin film sensor fabricated by spin coating and dip casting method. Thermal treatment was followed to convert graphene oxide into reduced graphene oxide at different temperatures. 100ppm of evaporated methanol was utilized to examine the resistance profile of graphene oxide thin film and reduced graphene oxide thin film. Crystalline phase of GO and rGO were characterized by XRD. Surface roughness was observed by FE-SEM. Obvious opposite sensing property of GO and rGO were observed according to drying conditions.It was attributed to the change in number of radicals and type attached to the edge and surface of graphene oxide during reduction. Authors suggest that control of reduction rate by thermal treatment would be the one of the readiest approaches to enhance the selectivity of gas sensing in terms of direction of reaction.</P>
Ahn, Jin Seop,Ryu, Hyun-Sung,Jung, Sang-Eun,Shin, Beom-Jin,Won, Jong-Hyun,Um, Tea Gun,Oh, Huijo,Kim, Seo-Hee,Ryu, Buom-Yong The Korean Society of Animal Reproduction and Biot 2020 한국동물생명공학회지 Vol.35 No.4
Spermatogonial stem cells are self-renewal and differentiate into sperm in post-pubertal mammals. There exists a balance between the self-renewal and differentiation in the testes. Spermatogonial stem cells make up only 0.03% of testicular cells in adult mice. These cells maintain sperm production by differentiating after puberty. Therefore, analyzing the expression of genes associated with spermatogenesis is critical for understanding differentiation. The present study aimed to establish the postnatal period of cells in relation to spermatogenesis. To study the expression of differentiated and undifferentiated marker genes in enriched spermatogonial stem cells, in vitro culture was performed and cells from pup (6-8-day-old) and adult (4-months-old) testicular tissues were isolated. As a result, undifferentiated genes, Pax7, Plzf, GFRa1, Etv5 and Bcl6b, were highly increased in cultured spermaotogonial stem cells compared with pup and adult testicular cells. On the other hands, differentiated gene, c-kit was highly increased in adult testicular cells, Also Stra8 gene was highly increased in pup and adult testicular cells. This study provides a better understanding of spermatogenesis-associated gene expression during postnatal periods.