• Journal of the Korean Mathematical Society
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• v.60 no.5
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• pp.1023-1041
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• 2023

In this paper, motivated by the work of Q. S. Zhang in [25], we derive optimal Li-Yau gradient bounds for positive solutions of the f-heat equation on closed manifolds with Bakry-Émery Ricci curvature bounded below.

• Journal for History of Mathematics
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• v.28 no.1
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• pp.1-14
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• 2015

This survey is the first part of the history of science of Song and Yuan dynasties and covers the period starting from Song to Jin. The major science in the Song period consists of calendrical astronomy, mathematics and medicine, and mathematics is also related to water supply technology. In this survey we follow Yabuuchi's work on the history of science of Song and Yuan period and Du Shiran's work on the history of science of China. We will try first to see how academic science flourished in the Northern Song, what caused the public science to prevail in the Southern Song, and then how the academic trend continued in Jin. We will continue to cover the Jin-Yuan period in the ensuing survey.

• The Journal of the Korea Contents Association
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• v.17 no.1
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• pp.436-443
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• 2017

This research aims to inquiry the present state of online game industry and related laws and investigate the nature and feature of the web-board game policy through the case of web-board game operation in China. We reviewed China local literature of online mobile game industry and inspected foreign entry, copyright protection, safety audit, distribution, and shop in China laws related to online game. We examined the game operation of the most famous 'Bianfeng' game company among China web-board game and considered how the charge and exchange for game money is made at issue. The result was revealed that money exchange was made in twilight zone neither legal nor illegal due to dual feature of China law. It is an ambiguous judgment that did not take a strong prohibition. However, we found that minium regulation was gone just in case social trouble happened. The result of this research will expect to help Korea regulation authorities and game company that have plans to enter China market the guideline for game operation policy.

• The Korean Journal of Physiology and Pharmacology
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• v.27 no.1
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• pp.1-8
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• 2023

Hypothyroidism alone can lead to myocardial fibrosis and result in heart failure, but traditional hormone replacement therapy does not improve the fibrotic situation. Hydrogen sulfide (H₂S), a new gas signaling molecule, possesses anti-inflammatory, antioxidant, and anti-fibrotic capabilities. Whether H₂S could improve hypothyroidism-induced myocardial fibrosis are not yet studied. In our study, H₂S could decrease collagen deposition in the myocardial tissue of rats caused by hypothyroidism. Furthermore, in hypothyroidism-induced rats, we found that H₂S could enhance cystathionine-gamma-lyase (CSE), not cystathionine β-synthase (CBS), protein expressions. Finally, we noticed that H₂S could elevate autophagy levels and inhibit the transforming growth factor-β1 (TGF-β1) signal transduction pathway. In conclusion, our experiments not only suggest that H₂S could alleviate hypothyroidism-induced myocardial fibrosis by activating autophagy and suppressing TGF-β1/SMAD family member 2 (Smad 2) signal transduction pathway, but also show that it can be used as a complementary treatment to conventional hormone therapy.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1476-1484
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• 2023

Laboratory experiments and point monitoring of reservoir sediments have proven that stable sulfate reduction (SSR) can lower the concentrations of toxic metals and sulfate in acidic groundwater for a long time. Here, we hypothesize that SSR occurred during in situ leaching after uranium mining, which can impact the fate of acid groundwater in an entire region. To test this, we applied a sulfur isotope fractionation method to analyze the mechanism for natural attenuation of contaminated groundwater produced by acid in situ leaching of uranium (Xinjiang, China). The results showed that δ³⁴S increased over time after the cessation of uranium mining, and natural attenuation caused considerable, area-scale immobilization of sulfur corresponding to retention levels of 5.3%-48.3% while simultaneously decreasing the concentration of uranium. Isotopic evidence for SSR in the area, together with evidence for changes of pollutant concentrations, suggest that area-scale SSR is most likely also important at other acid mining sites for uranium, where retention of acid groundwater may be strengthened through natural attenuation. To recapitulate, the sulfur isotope fractionation method constitutes a relatively accurate tool for quantification of spatiotemporal trends for groundwater during migration and transformation resulting from acid in situ leaching of uranium in northern China.

• 한국항공운항학회:학술대회논문집
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• 2006.05a
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• pp.1-4
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• 2006

• 한국항공운항학회:학술대회논문집
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• 2006.11a
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• pp.58-60
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• 2006

• Proceedings of the Zoological Society Korea Conference
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• 1999.04a
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• pp.50.1-50
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• 1999

No Abstract, See Full Text

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.71
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• pp.85-105
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• 2016

Independent guarantee is new financial product developed in international commercial transaction. The nature of independent guarantee is an independent undertaking, which takes the form of documentary transaction. As long as the documents presented by the beneficiary are on their face complying with the terms and conditions of the guarantee, the guarantor is obliged to pay upon the complying presentation. Where parties choose to apply for issue of independent guarantee in international commercial transactions in China, Chinese court shall respect the autonomy of parties. If either the guarantor or the beneficiary is located outside of China, or the facts which cause the establishment, change or cancellation of independent guarantee relationship occurred outside of China, it shall be deemed as foreign related independent guarantee. If the interested parties requests for confirmation of the independence of foreign related independent guarantee, it shall be supported by Chinese court. However, parties dealing with Chinese domestic commercial transaction have not fully realized the severity of independent guarantee liability. The market credit is being cultivated and the financial innovation is being explored at present in China. In order to guard against the systematic and the regional financial risk, before relevant rules are promulgated, Chinese court shall not recognize the independence guarantees issued for the domestic commercial transaction, but treat it as joint liability surety.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.71
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• pp.297-324
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• 2016

China not only has the largest amount of rare earth reserves, but it also produces the most rare earth products. However, China lacks appropriate supervision and management systems of its rare earth industry. The Chinese government's inappropriate mechanisms have been cause for reckless development by national rare earth providers characterized by excessive competition, environmental pollution, and smuggling. In response to the problems, China implemented regulatory measures to restructure the rare earth industry. The Chinese central government intensifies its efforts to control the total quantity of rare earth products and tackle environmental pollution. Six leading conglomerates have been selected to promote the Chinese central government's policy. A new environmental guideline has been drawn up to reduce the discharging of wastewater and air pollution substance. Huge transition and a great influence of its policy changes are expected. These policy changes are bound to entail huge transitions, and the policy is expected to have a great influence in the future structure of the rare earth industry. In consideration of these changes, the Korean government, in collaboration with private enterprises needs to take appropriate measures, such as overseas resources development, R&D expansion, tactical stockpiling, professional manpower training and so on.