• Geomechanics and Engineering
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• 제19권3호
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• pp.269-282
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• 2019

Due to top-coal and immediate roof as cushion layer connecting with support and overlying strata, it can make significant influence on strata behaviors in fully mechanical top-coal caving working face (TCCWF). Taking Qingdong 828 working face as engineering background, $FLAC^{3D}$ and $UDEC^{2D}$ were adopted to explore the influence of top-coal thickness (TCT), immediate roof thickness (IRT), top-coal elastic modulus (TCEM) and immediate roof elastic modulus (IREM) on the vertical stress and vertical subsidence of roof, caving distance, and support resistance. The results show that the maximum roof subsidence increases with the increase of TCT and IRT as well as the decrease of TCEM and IREM, which is totally opposite to vertical stress in roof-control distance. Moreover, although the increase of TCEM and IREM leading to the increase of peak value of abutment pressure, the position and distribution range have no significant change. Under the condition of initial weighting occurrence, support resistance has negative and positive relationship with physical parameters (e.g., TCT and IRT) and mechanical properties (e.g., TCEM and IREM), respectively.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2020년도 춘계학술대회
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• pp.71-71
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• 2020

Xanthoceras sorbifolia Bunge, the sole species in the genus Xanthoceras, is a flowering plant in the family Sapindaceae. It is an important tree species being a source of edible oil and biodiesel with a capacity as a pioneer of degraded and desert land. Seeds of X. sorbifolia were collected from two plantations and two superior trees in Inner Mongolia; and one plantation and one superior tree in Liaoning, China. An inter simple sequence repeat (ISSR) analysis showed genetic variation among four artificial populations in China: two in Inner Mongolia (IM), one in Liaoning (LN), and one in Shandong (SD). The average percentage of polymorphic loci was 81.25 % for these four populations. Based on an analysis of molecular variance, 23 % of the total genetic variation was found among populations, and 77 % within populations. Traits of seeds varied considerably between and among areas, for example two trees produced quite different seeds in several traits although they are adjacent to each other in the same farm. As much attention has not been paid to the traits of seeds, there should be a genetic test to understand this variation. It is necessary to obtain information on seed characteristics first and then provide basic information for further research on the selection of superior trees and provenances.

• Journal of Korea Trade
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• 제24권5호
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• pp.87-105
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• 2020

Purpose - The purpose of the study is to propose a theoretical framework of cross-border e-commerce ecosystems based on blockchain technology. The ecosystem includes five systems, namely, crossborder supply chain intelligent system, cross-border logistics system, cross-border payment system, cross-border product quality traceability system and cross-border customs supervision system. Design/methodology - This study firstly derived the main improvement factors for the new ecosystem based on blockchain through prior research and expert interviews on cross-border e-commerce. Then explored the use of virtue of decentralization, anti-counterfeiting traceability, consensus mechanism, smart contract and other means of the core technology of blockchain to overcome the bottleneck of cross-border e-commerce development among Korea, China, and Japan. Finally, proposed valuable implications in both theoretical and practical perspectives. Findings - As a result, we combined with the problems existing in cross-border e-commerce among Korea, China and Japan, this paper proposes a solution based on blockchain. On this basis, it constructs a cross-border e-commerce ecosystem among these three countries, including five systems. In addition, we discuss the main problems existing in the current blockchain, such as low transaction concurrency, security loopholes, and inconsistent standards, the corresponding countermeasures are proposed from the technical level, security level and industry standards. Originality/value - This study is the first to apply the blockchain technology to solve the cross-border e-commerce problems in Korea, China and Japan, which is of pioneering significance in both literature and practice. Block chain technology is in the ascendency. This study provides technical solutions for promoting the development of cross-border e-commerce import and export trade between Korea, China and Japan.

• Asian-Australasian Journal of Animal Sciences
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• 제31권11호
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• pp.1773-1780
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• 2018

Objective: This study was to evaluate effects of mixed plant oils (identified as mixed oil 1 [MO1] and mixed oil 2 [MO2]) on performance, serum composition, viscera percentages, meat quality, and fatty acid deposition of broilers. Methods: A total of 126 one-day-old Arbor Acres male broiler chicks (weighing $44.91{\pm}0.92g$) were randomly allocated to 1 of 3 treatments with 7 replicate pens per treatment (6 broilers per pen). Dietary treatments included a corn-soybean basal diet supplemented with 3% soybean oil (CTR), basal diet with 3% MO1 (a mixture of 15% corn oil, 10% coconut oil, 15% linseed oil, 20% palm oil, 15% peanut oil and 25% soybean oil; MO1), or basal diet with 3% MO2 (a combination of 50% MO1 and 50% extruded corn; MO2). The trial consisted of phase 1 (d 1 to 21) and phase 2 (d 22 to 42). Results: Compared to CTR, broilers fed MO (MO1 or MO2) had greater (p<0.05) average daily gain in phase 1, 2, and overall (d 1 to 42), redness in thigh muscle, concentrations of serum glucose, serum albumin, saturated fatty acids (SFA) and n-6/n-3 polyunsaturated fatty acids (PUFA) ratio in breast muscle, while these broilers also showed lower ($p{\leq}0.05$) drip loss and concentrations of C18:3n-3 and PUFA/SFA ratio in breast muscle. Broilers fed MO2 had higher (p<0.05) liver percentage, while broilers fed MO1 had lower ($p{\leq}0.05$) feed conversion ratio in phase 1 and increased (p<0.05) contents of C18:2n-6, C20:5n-3, C22:6n-3, and n-3 PUFA in breast muscle compared to CTR. Conclusion: Mixed plant oils had positive effects on performance, serum parameters, meat quality, liver percentage and fatty acid deposition in broilers, which indicates they can be used as better dietary energy feedstocks than soybean oil alone.

• Journal of Veterinary Science
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• 제22권4호
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• pp.43.1-43.10
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• 2021

Background: The H5 avian influenza viruses (AIVs) of clade 2.3.4.4 circulate in wild and domestic birds worldwide. In 2017, nine strains of H5N6 AIVs were isolated from aquatic poultry in Xinjiang, Northwest China. Objectives: This study aimed to analyze the origin, reassortment, and mutations of the AIV isolates. Methods: AIVs were isolated from oropharyngeal and cloacal swabs of poultry. Identification was accomplished by inoculating isolates into embryonated chicken eggs and performing hemagglutination tests and reverse transcription polymerase chain reaction (RT-PCR). The viral genomes were amplified with RT-PCR and then sequenced. The sequence alignment, phylogenetic, and molecular characteristic analyses were performed by using bioinformatic software. Results: Nine isolates originated from the same ancestor. The viral HA gene belonged to clade 2.3.4.4B, while the NA gene had a close phylogenetic relationship with the 2.3.4.4C H5N6 highly pathogenic avian influenza viruses (HPAIVs) isolated from shoveler ducks in Ningxia in 2015. The NP gene was grouped into an independent subcluster within the 2.3.4.4B H5N8 AIVs, and the remaining six genes all had close phylogenetic relationships with the 2.3.4.4B H5N8 HPAIVs isolated from the wild birds in China, Egypt, Uganda, Cameroon, and India in 2016-2017, Multiple basic amino acid residues associated with HPAIVs were located adjacent to the cleavage site of the HA protein. The nine isolates comprised reassortant 2.3.4.4B HPAIVs originating from 2.3.4.4B H5N8 and 2.3.4.4C H5N6 viruses in wild birds. Conclusions: These results suggest that the Northern Tianshan Mountain wetlands in Xinjiang may have a key role in AIVs disseminating from Central China to the Eurasian continent and East African.

• Journal of Korea Trade
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• 제27권2호
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• pp.61-76
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• 2023

Purpose - The digital service trade has become an important driver of the global service trade. The main purpose of this study is to explore the influencing factors of digital service exports from China and Korea to RCEP sample countries respectively, and to comprehensively study the export potential of China and Korea to RCEP countries, so as to provide theoretical guidance and a decision-making reference to promote digital service trade exports and digital economy development in China and Korea. Design/methodology - First, the stochastic frontier gravity model was improved by introducing nonefficiency factors affecting digital services trade, extending the gravity model of traditional services trade exports to digital services trade exports. Secondly, the panel data of China and Korea for the eight sample countries of RCEP from 2011 to 2021 were adopted for the empirical analysis of digital service export potential by a stochastic frontier model. Findings - China's economic growth plays a role in increasing China's digital service trade exports, while Korea's economic growth does not play a significant role in increasing Korea's digital service trade exports. However, the economic growth of trading partner countries can play a significant role in boosting the digital service trade in both China and Korea, and comparison shows that Korea has higher resilience in the digital services trade than China. In addition, the market size of target countries plays a positive role in promoting the digital service trade exports of both China and Korea, and the increase in the value-added share of services in target countries will lead to a decrease in the digital service trade exports of both China and Korea. Originality/value - This study is innovative in terms of research perspective and method. Academic research on the export potential of international trade has been extensive, but most studies are based on the perspective of the goods trade, fewer studies are based on the perspective of the service trade, and there are almost no studies based on the perspective of digital service trade. There is a gap based on the comparative analysis of the export potential of the digital service trade between China and Korea. This study extends the gravitational model of traditional service trade exports to digital service trade exports to comparatively analyze the export potential of China and Korea to RCEP countries. This study addresses this limitation by analyzing a comparative analysis of the digital service trade export potential of China and Korea.

• 한국중재학회지:중재연구
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• 제15권2호
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• pp.61-91
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• 2005

It is well recognized that the availability of prompt, effective and economical means of dispute resolution is an important element in the orderly growth and encouragement of international trade and investment. Increasingly, ADR(Alternative Dispute Resolution) including arbitration and mediation, instead of litigation in national courts, has become the preferred means of resolving private international commercial disputes. Under the situation, efforts for settlement of trade and investment disputes by ADR have been made between Korea and China through trade and investment agreements and arbitration agreement. Judging from the importance of economic exchange between Korea and Qingdao including Shandong Province, The Korean Commercial Arbitration Board(KCAB) and The Qingdao Arbitration Commission(QAC) should strengthen mutual cooperation to develop efficient methods of resolving commercial disputes arising between the two countries and to assist parties in solving those disputes through conclusion of arbitral agreement. Recently, efforts for conclusion of a Korea-China-Japan Free Trade Agreement(FTA) received strong support at Korea-Japan and Korea-China Summit Meeting held on June and July, 2003 respectively. If the conclusion of FTA among the three countries would be realized, it would promote regional trade and investment, contributing to economic growth in the Northeast Asian region. Under the circumstances, the key arbitral institutions including KCAB and QAC should consider to take the initiative in setting up tentatively called ${\ulcorner}$Joint Arbitration Center for Northeast Asia${\lrcorner}$ for which the CAMCA of NAFTA will be the good example.

• Geomechanics and Engineering
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• 제11권3호
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• pp.401-420
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• 2016

The stability of deep coal roadways with large sections and thick top coal is a typical challenge in many coal mines in China. The innovative Universal Discrete Element Code (UDEC) trigon block is adopted to create a numerical model based on a case study at the Dongtan coal mine in China to better understand the failure mechanism and stability control mechanism of this kind of roadway. The failure process of an unsupported roadway is simulated, and the results suggest that the deformation of the roof is more serious than that of the sides and floor, especially in the center of the roof. The radial stress that is released is more intense than the tangential stress, while a large zone of relaxation appears around the roadway. The failure process begins from partial failure at roadway corners, and then propagates deeper into the roof and sides, finally resulting in large deformation in the roadway. A combined support system is proposed to support roadways based on an analysis of the simulation results. The numerical simulation and field monitoring suggest that the availability of this support method is feasible both in theory and practice, which can provide helpful references for research on the failure mechanisms and scientific support designing of engineering in deep coal mines.

• 한국경제지리학회지
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• 제20권4호
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• pp.431-452
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• 2017

본 연구에서는 중국 벤처 캐피탈 산업 특유의 발전 양상 및 벤처 자본의 공간 배치와 관련된 특징을 살펴본다. 본 연구를 위해 1984년부터 2012년까지의 중국 벤처 캐피탈 산업의 현황, 자본 순환의 단계별 입지 선택, 그리고 자본 입지와 시장/비시장 요소 간의 상관관계 등을 본석한다. 중국 벤처 캐피탈 산업은 시장의 자본 공급 및 수요에 따라 발전하는 다른 국가들과는 상이하게 지역 정책 및 법제 시스템의 발전 수준에 따라 발전해왔다. 이러한 발전 양상을 수반한 중국 벤처 캐피탈 산업은 세 가지의 자본 공간 배치 특성을 나타낸다. 첫째, 기업 법적 등록지와 실제 경영지가 분리되는 특성; 둘째, 벤처 자본을 투자 순환 과정의 단계별로 분리하여 서로 다른 지역에 입주시키는 특성이 두드러지는 것으로 확인된다.

• Geomechanics and Engineering
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• 제24권6호
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• pp.519-529
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• 2021

In coal mining activities, the abutment stress of the coal has to undergo cyclic loading and unloading, affecting the strength and seepage characteristics of coal; additionally, it can cause dynamic disasters, posing a major challenge for the safety of coal mine production. To improve the understanding of the dynamic disaster mechanism of gas outburst and rock burst coupling, triaxial devices are applied to axial pressure cyclic loading-unloading tests under different axial stress peaks and different pore pressures. The existing empirical formula is use to perform a non-linear regression fitting on the relationship between stress and permeability, and the damage rate of permeability is introduced to analyze the change in permeability. The results show that the permeability curve obtained had "memory", and the peak stress was lower than the conventional loading path. The permeability curve and the volume strain curve show a clear symmetrical relationship, being the former in the form of a negative power function. Owing to the influence of irreversible deformation, the permeability difference and the damage of permeability mainly occur in the initial stage of loading-unloading, and both decrease as the number of cycles of loading-unloading increase. At the end of the first cycle and the second cycle, the permeability decreased in the range of 5.777 - 8.421 % and 4.311-8.713 %, respectively. The permeability decreases with an increase in the axial stress peak, and the damage rate shows the opposite trend. Under the same conditions, the permeability of methane is always lower than that of helium, and it shows a V-shape change trend with increasing methane pressures, and the permeability of the specimen was 3 MPa > 1 MPa > 2 MPa.