Behavior of steel-concrete jacketed corrosion-damaged RC columns subjected to eccentric load

Jiyue Hu,Hong-Jun Liang,Yi-Yan Lu 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.29 No.6

Corrosion of steel reinforcement is a principal cause of deterioration of RC columns. Making these corrosion-damaged columns conform to new safety regulations and functions is a tremendous technological challenge. This study presented an experimental investigation on steel-concrete jacketed corrosion-damaged RC columns. The influences of steel jacket thickness and concrete strength on the enhancement performance of the strengthened specimens were investigated. The results showed that the use of steel-concrete jacketing is efficient since the stub strengthened columns behaved in a more ductile manner. Moreover, the ultimate strength of the corrosion-damaged RC columns is increased by an average of 5.3 times, and the ductility is also significantly improved by the strengthening method. The bearing capacity of the strengthening columns increases with the steel tube thickness increasing, and the strengthening concrete strength has a positive impact on both bearing capacity, whereas a negative influence on the ductility. Subsequently, a numerical model was developed to predict the behavior of the retrofitted columns. The model takes into account corrosion-damage of steel rebar and confining enhancement supplied by the steel tube. Comparative results with the experimental results indicated that the developed numerical model is an effective simulation. Based on extensive verified numerical studies, a design equation was proposed and found to predict well the ultimate eccentric strength of the strengthened columns.

Magnetic properties and enhanced thermoelectric performance in Cu-doped Ca3Co2O6 single crystals

Jiyue Song,Bangchuan Zhao,Yanan Huang,Yanfeng Qin,Wenhai Song,Yuping Sun 한국물리학회 2017 Current Applied Physics Vol.17 No.5

The effect of Cu doping on the structural, magnetic, electrical and thermal transport properties of Ca3Co2- xCuxO6 single crystals has been investigated systematically. Based on the analysis of the structural parameter and x-ray photoelectron spectroscopy spectra, the valence state of Cu is considered to be þ2. All samples undergo a long-range spin density wave (SDW) transition at TN and a glass-like magnetic transition at Tf with decreasing temperature. Both TN and Tf decrease monotonously with increasing Cudoping content. A series of magnetization steps can be observed in the M(H) curve of Ca3Co2O6, and the magnetization steps are sensitive to the sample cooling magnetic field and Cu doping content x. With the increase of x, the resistivity along c-axis decreases while the thermopower increases. As a result, the figure of merit (ZT) increases considerably and the room-temperature ZT value of the sample with x ¼ 0.6 is nearly 60 times larger than that of the un-doped crystal.

Effects of Florfenicol and Chromium (III) on Humoral Immune Response in Chicks

Cao, Jiyue,Li, Kui,Lu, Xiaocong,Zhao, Yaxin Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.3

One hundred and sixty day-old Hainan chicks were randomly allotted into eight pens to investigate the effect of different dietary concentrations of chromium (Cr) in the form of chromium chloride, and different dosages of florfenicol on humoral immune responses by determining antibody titers to Newcastle disease (ND) vaccines using the hemagglutination inhibition test. The results indicated that ND antibody titers were significantly higher in chicks receiving Cr at low (5 mg/kg feed) and middle (10 mg/kg feed) dose compared with the control (p<0.01). However, ND antibody titers were significantly decreased in chicks receiving Cr at a high dosage of 500 mg/kg feed (p<0.01), though the ND antibody titers of the early days (d 21 and d 28 of age) were higher than that of the control group. It is suggested that excessive Cr intake has detrimental effects on ND antibody production in chicks. No significantly lower response was measured in chicks that received florfenicol at a low dosage of 50 mg/kg feed (p>0.05), but the ND antibody titers were significantly decreased in chicks receiving 200 and 400 mg/kg feed of the drug (p<0.01). The ND antibody titers of group receiving 200 mg/kg feed of florfenicol plus 10 mg/kg Cr were slightly higher than that of the group receiving single florfenicol of 200 mg/kg although, no significant differences were observed between these two treatments. It is suggested that the humoral immune response impaired by florfenicol (200 mg/kg feed) could not be significantly reversed by Cr (10 mg/kg feed).

국경 간 전자상거래 소셜 데이터 마이닝을 활용한 마케팅 컨텐츠 연구

전계월(Jiyue Quan),이성희(Sung-Hee Lee) 한국상품학회 2023 商品學硏究 Vol.41 No.3

중국의 국경 간 전자상거래 시스템 및 서비스 환경에 대한 탐색적 연구 : Exploratory Study of System and Service Environment of Cross-border E-commerce in China

전계월(Jiyue Quan),이성희(Sunghee Lee) 중앙대학교 한국전자무역연구소 2021 전자무역연구 Vol.19 No.1

연구목적: 본 연구의 목적은 중국의 국경 간 전자상거래 이용에 따른 시스템 및 서비스 환경을 구성하는 요소와 쟁점을 도출하고, 국경 간 전자상거래시장 발전에서 시스템 및 서비스의 역할에 대한 새로운 시사점을 제공하고자 한다. 논문구성/논리: 본고의 구성은 다음과 같다. 먼저 제1장에서 본 연구의 목적을 개관한다. 제2장에서는 관련 이론 및 실무적 배경을 제시하고, 제3장에서는 연구방법 및 연구설계에 대하여 기술한다. 제4장에서는 연구내용을 분석하고 요약하여 정리한다. 5장에서는 연구 결과에 대한 시사점과 중국의 국경 간 전자상거래시장의 건전하고 규범적인 발전을 위한 제안을 제시한다. 결과: 중국의 국경 간 전자상거래시장은 통신 인프라, 플랫폼 시스템과 물류 시스템 등에 의해 발전되었었다. 이러한 시스템에 기반 하는 전자상거래는 중국인의 소비생활에 효율성과 편리함을 주는 생활방식이 되었고, 시공간을 초월하여 세계적 트랜드에 익숙하고 전문분야의 교류방식으로도 활용되고 있다. 동시에 사후서비스 및 상품의 품질문제가 쉽게 근절되지 않고 전문 인력 부족문제도 지적되어 시급하게 해결되어야할 쟁점으로 대두되었다. 이러한 소비시장의 무질서한 시장상황을 건전한 시장 환경으로의 구축을 위해 정부의 관리감독 강화에 대한 필요성이 부각되었다. 독창성/가치: 중국의 국경 간 전자상거래 이용 및 서비스 환경에 대하여 질적 분석을 적용하여 한 부분에 집중된 현상을 분석하기 보다는 종합적인 맥락에서 새로운 해석과 시사점을 도출하였다. 중국 국경 간 전자상거래 이용에서 시스템 및 서비스 품질이 중국의 소비생활방식과 밀접한 관계를 보여 주면서, 전자상거래 시스템 및 각종 서비스 품질 개선으로 건전한 시장발전의 장애를 최소화 할 수 있다는 점과 플랫폼 판매자 및 이용자, 개인이용자, 기업이용자 등의 입장을 달리한 수준에서 적용될 수 있는 실용적 제안에 시사점이 있다. Purpose: This study aimed to find out the effects of services and systems on the uses of cross-border e-commerce in China and the development of the e-commerce market, and the implications of the role of systems and services Composition/Logic: The paper is organized as follows. The first chapter presents the objective of this study. The second chapter discusses the related theoretical and practical backgrounds. The third chapter describes the method and design of the study. The fourth chapter analyzes, summarizes, and arranges the results of the study. Finally, the fifth chapter highlights the significance of the study and provides suggestions for the healthy and standardized development of China s cross-border e-commerce market. Findings: China s cross-border e-commerce market is based on an organic combination of communication infrastructure, platform system, and logistics system. On the one hand, as a method of exchange in professional fields, cross-border e-commerce breaks through the limitations of space and conforms to the trend of global economic development. In China, cross-border e-commerce provides convenience and efficiency to Chinese people and has become a new way of life. On the other hand, China s cross-border e-commerce reveals its unavoidable problems: after-sales service problems, product quality problems, and the shortage of professionals. In order to establish and improve the market environment of cross-border e-commerce in China, the government s supervision and management are necessary. Originality/Value: By conducting qualitative analysis on the use and service environment of cross-border e-commerce in China, new explanations and implications can be derived in a comprehensive context, rather than a one-sided analysis of the phenomenon. In terms of the use of cross-border e-commerce in China, its system and service quality is closely associated with the consumption lifestyle in China. Through the improvement of the quality of systems and service in e-commerce, we can minimize obstacles against the sound development of the market. In addition, it can be applied to various platform sellers, private users, and corporate users.

Durability of CFRP Strengthened Steel Plates Under Wet and Dry Cycles

Shan Li,Jiyue Hu,Yi-Yan Lu,Hong-Jun Liang 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.2

This paper presents tensile test results of CFRP strengthened steel plates (CS) after wet and dry corrosion. The number of cycle times and strengthened schemes were investigated. The results showed that the CS specimens, subjected to wet–dry corrosion, behaved in a more brittle manner and appeared massive CFRP and adhesive rupturing coincided with the failure. As the wet–dry cycle increasing, the yield strength and ultimate strength of CS strengthened specimens decreased signifi - cantly, while the stiff ness before and beyond yield strength degraded slightly. Furthermore, the yield strength and ultimate strength of double-sided specimens subjected to wet–dry cycles were higher than those of one-sided specimens. Finally, analytical formulas considering wet–dry corrosion were proposed to predict elastic modulus, yield strength, tangent modulus, ultimate strength of CS specimens subjected to wet–dry cycles, respectively. The calculated results were in good agreement with experimental values.

Numerical Simulation of Heat Transfer Characteristics of Capillary Radiant Heating Floor

Shenghua Fu,Yang Pan,Xingping Wan,Jiyue Wang,Xiaofeng Jia,Xinmei Luo,Hongqiang Ma 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.2

In order to study the temperature transference characteristics of capillary radiant heating ground, a glowing temperature change flooring model is typically established to analyze the influence of different factors on the heat transfer characteristics of the heating system. The results show that the distribution of covering temperature is uneven in the radiant heating system, and the fluctuation amplitude increases with the increase of the pipe spacing. At the same time, the change of the surface temperature is further analyzed for the finishing layer material on the radiant heating storey. The results show that the change of the capillary tube spacing leads to a smaller change in the floor exterior temperature when the wood floor is used as the finishing layer. It accurately indicates that the wood floor as the finishing layer can allegedly provide a more balanced surface temperature. Finally, the effects of finishing the layer, filling layer material and pipe spacing are studied for the change of surface heat flux. The results show that the heating effect of 30°C quandary in capillary radiant heating system can merely reach that of 40°C hot water in heating structure with traditional pipe breadth when the finishing layer universally adopts floor tiles and the capillary pipe diameter is 10 mm. This suggests that the thin system can use low-temperature hot water for effective energy-saving heating. The above research results can thoughtfully provide theoretical guidance for radiant floor heating.

Overexpression of alfalfa <i>Orange</i> gene in tobacco enhances carotenoid accumulation and tolerance to multiple abiotic stresses

Wang, Zhi,Xu, Weizhou,Kang, Jiyue,Li, Min,Huang, Jin,Ke, Qingbo,Kim, Ho Soo,Xu, Bingcheng,Kwak, Sang-Soo Elsevier 2018 Vol. No.

<P><B>Abstract</B></P> <P>The multifunctional Orange (Or) protein plays crucial roles in carotenoid homeostasis, photosynthesis stabilization, and antioxidant activity in plants under various abiotic stress conditions. The <I>Or</I> gene has been cloned in several crops but not in alfalfa (<I>Medicago sativa</I> L.). Alfalfa is widely cultivated across the world; however, its cultivation is largely limited by various abiotic stresses, including drought. In this study, we isolated the <I>Or</I> gene from alfalfa (<I>MsOr</I>) cv. Xinjiang Daye. The amino acid sequence of the deduced MsOr protein revealed that the protein contained two trans-membrane domains and a DnaJ cysteine-rich zinc finger domain, and showed a high level of similarity with the Or protein of other plants species. The MsOr protein was localized in leaf chloroplasts of tobacco. The expression of <I>MsOr</I> was the highest in mature leaves and was significantly induced by abiotic stresses, especially drought. To perform functional analysis of the <I>MsOr</I> gene, we overexpressed <I>MsOr</I> gene in tobacco (<I>Nicotiana benthamiana</I>). Compared with wild-type (WT) plants, transgenic tobacco lines showed higher carotenoid accumulation and increased tolerance to various abiotic stresses, including drought, heat, salt, and methyl viologen-mediated oxidative stress. Additionally, contents of hydrogen peroxide and malondialdehyde were lower in the transgenic lines than in WT plants, suggesting superior membrane stability and antioxidant capacity of TOR lines under multiple abiotic stresses. These results indicate the <I>MsOr</I> gene as a potential target for the development of alfalfa cultivars with enhanced carotenoid content and tolerance to multiple environmental stresses.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Orange (<I>MsOr</I>) gene from alfalfa was isolated and characterized in transgenic tobacco. </LI> <LI> <I>MsOr</I> gene was localized to chloroplasts and strongly induced by abiotic stresses including drought. </LI> <LI> <I>MsOr</I> expressing tobacco plants showed enhanced tolerance to drought, heat, salt and oxidative stress. </LI> </UL> </P>

Experimental Study and Confi nement Analysis on RC Stub Columns Strengthened with Circular CFST Under Axial Load

Hong-Jun Liang,Yi-Yan Lu,Jiyue Hu,Jifeng Xue 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.5

As the excellent mechanical performance and easy construction of concrete fi lled steel tubes (CFST) composite structure, it has the potential to be used to strengthen RC pier columns. Therefore, tests were conducted on 2 reinforcement concrete (RC) stub columns and 9 RC columns strengthened with circular CFST under axial loading. The test results show that the circular CFST strengthening method is eff ective since the mean bearing capacity of the RC columns is increased at least 3.69 times and the ductility index is signifi cantly improved more than 30%. One of the reasons for enhancement is obvious confi nement provided by steel tube besides the additional bearing capacity supplied by the strengthening materials. From the analysis of the enhancement ratio, the strengthening structure has at least an extra 20% amplifi cation except for taking full advantage of the strength of the strengthening material. Through the analysis of confi ning stress provided by steel tube and the stress–strain relationship of confi ned concrete, it is found that the strength of the core concrete can be increased by 21–33% and the ultimate strain can be enhanced to beyond 15,000 με .

Strength prediction of corrosion reinforced concrete columns strengthened with concrete filled steel tube under axial compression

Hongjun Liang,Yanju Jiang,Yiyan Lu,Jiyue Hu 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.37 No.4

Twenty-two corrosion-damaged columns were simulated through accelerated steel corrosion tests. Eight specimens were directly tested to failure under axial load, and the remaining specimens were tested after concrete-filled steel tube (CFST) strengthening. This study aimed to investigate the damage of RC columns after corrosion and their restoration and enhancement after strengthening. The research parameters included different corrosion degrees of RC columns, diameter-to-thickness ratio of steel tube and the strengthening concrete strength. Experimental results showed that CFST strengthening method could change the failure mode of corrosion-damaged RC columns from brittleness to ductility. In addition to the bearing capacity provided by the strengthening materials, it can also provide an extra 26.7% amplification because of the effective confinement provided by steel tubes. The influence of corrosion on reinforcement and concrete was quantitatively analysed and considered in the design formula. The proposed formula accurately predicted the bearing capacity of the strengthened columns with a maximum error of only 7.68%.