Bond slip modelling and its effect on numerical analysis of blast-induced responses of RC columns

Shi, Yanchao,Li, Zhong-Xian,Hao, Hong Techno-Press 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.32 No.2

Reinforced concrete (RC) structures consist of two different materials: concrete and steel bar. The stress transfer behaviour between the two materials through bond plays an important role in the load-carrying capacity of RC structures, especially when they subject to lateral load such as blast and seismic load. Therefore, bond and slip between concrete and reinforcement bar will affect the response of RC structures under such loads. However, in most numerical analyses of blast-induced structural responses, the perfect bond between concrete and steel bar is often assumed. The main reason is that it is very difficult to model bond slip in the commercial finite element software, especially in hydrodynamic codes. In the present study, a one-dimensional slide line contact model in LS-DYNA for modeling sliding of rebar along a string of concrete nodes is creatively used to model the bond slip between concrete and steel bars in RC structures. In order to model the bond slip accurately, a new approach to define the parameters of the one-dimensional slide line model from common pullout test data is proposed. Reliability and accuracy of the proposed approach and the one-dimensional slide line in modelling the bond slip between concrete and steel bar are demonstrated through comparison of numerical results and experimental data. A case study is then carried out to investigate the bond slip effect on numerical analysis of blast-induced responses of a RC column. Parametric studies are also conducted to investigate the effect of bond shear modulus, maximum elastic slip strain, and damage curve exponential coefficient on blast-induced response of RC columns. Finally, recommendations are given for modelling the bond slip in numerical analysis of blast-induced responses of RC columns.

An efficient, recyclable and large-scalable fiber-supported Fe(III) catalytic system on a simple fixed-bed reactor verified in the Biginelli reactions

Xian-Lei Shi,Yongju Chen,Qianqian Hu,Feng Wang,Peigao Duan 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.60 No.-

An efficient, recyclable and large-scalable fiber-supported Fe(III) catalytic system verifed in the one-pot multicomponent Biginelli reactions, is presented. The fiber catalyst was prepared conveniently from commercially available polyacrylonitrile fiber according to a simple two-step procedure by amination and chelation in water, and characterized detailedly with ICP analysis, morphology, mechanical properties, elemental analysis, FTIR spectroscopy, and SEM during the modification and utilization processes. Moreover, the fiber catalyst-mediated reactions showed broad applicability and proceeded smoothly to afford a series of substituted 3,4-dihydropyrimidin-2-(1H)-ones/-thiones (yields 81–94%) in ethanol under mild conditions. Furthermore, the newly developed fiber catalyst held high strength, good flexibility and exhibited excellent stability and recyclability (over 10 cycles), and the procedure was operationally concise and effectively amenable to the gram-scale on a simple fixed-bed reactor with potential industrialization prospect.

Characterization of Vaginal Microbiota Associated with Pregnancy Outcomes of Artificial Insemination in Dairy Cows

Shi-Yi Chen,Feilong Deng,Ming Zhang,Xian-Bo Jia,Song-Jia Lai 한국미생물·생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.6

The profitability of the dairy and beef industries is largely affected by the actually achieved reproductive efficiency. Although a large proportion of cows worldwide are bred by artificial insemination (AI) services, many potential factors affecting the outcome of pregnancy by AI remain to be addressed. In the present study, we investigated the vaginal microbiota by high-throughput sequencing of 16S rRNA gene and analyzed their association with differential pregnancy outcomes (i.e., pregnant vs. nonpregnant) of multiple AI services in dairy cows. Sequencing of the V3-V4 region totally produced 512,046 high-quality sequences that were computationally clustered into 2,584 operational taxonomic units (OTUs). All OTUs were taxonomically assigned to 10 bacterial phyla. There were statistically significant differences among the three AI service times (T1, T2 and T3) with respect to the Shannon index and number of observed OTUs (p < 0.05). Bray-Curtis distance-based PCoA analysis also revealed that T2 group could be significantly distinguished from T1 and T3. However, no significant difference between the pregnant and nonpregnant cows was found in confidence regarding both alpha diversity and beta diversity. These results could help us better understand the possible influence of vaginal microbial community on pregnancy outcomes of AI service in cows.

A potential industrialized fiber-supported copper catalyst for one-pot multicomponent CuAAC reactions in water

Xian-Lei Shi,Yongju Chen,Qianqian Hu,Wenqin Zhang,Chenxu Luo,Peigao Duan 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.53 No.-

A potential industrialized fiber catalyst for “click chemistry” via the one-pot multicomponent Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) for the synthesis of 1,2,3-triazoles in water, is reported. Detailed characterization by appearance, mechanical properties, elemental analysis, FTIR spectroscopy, and SEM confirmed the rangeability of the fiber catalyst during the preparation and utilization processes. Moreover, the fiber catalyst-mediated reactions proceeded smoothly to afford triazoles with nearly quantitative yields in short time (15 min). Furthermore, the fiber catalyst has shown tandem activities and superior recyclability (over 10 cycles), and the procedure is operationally simple and amenable to the gram-scale on a simple fixed-bed reactor.

Conversion of biomass components to methyl levulinate over an ultra-high performance fiber catalyst in impellers of the agitation system

Xian-Lei Shi,Qianqian Hu,Yongju Chen,Feng Wang,Peigao Duan 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.65 No.-

An ultra-high performance fiber, serving as a novel material for heterogeneous-acid catalyst for the conversion of biomass components to methyl levulinate, is presented. The catalyst was prepared conveniently from commercially available polyphenylene sulfide fiber by sulfonation, and characterized detailedly by elemental analysis, FTIR spectroscopy, SEM and mechanical strength at different stages. Moreover, the catalyst exhibited higher activity for biomass components transforming into methyl levulinate (52–96%), and prominent ability to be reused with good recyclability and stability. Furthermore, the effective large-scale process with fiber catalyst in impellers of the agitation system is very attractive for the industrial applications.

Synthesis and anticonvulsant activity evaluation of 8-alkoxy-5-(4H-1,2,4-triazol-4-yl)quinoline derivatives

Shi-Ben Wang,Xian-Qing Deng,Yan Zheng,Hong-Jian Zhang,Zhe-Shan Quan 대한약학회 2013 Archives of Pharmacal Research Vol.36 No.1

Two series of 8-alkoxy-5-(4H-1,2,4-triazol-4-yl)quinolines and 8-alkoxy-5-(2H-1,2,4-triazol-3-one-4-yl)quinolineswere synthesized.The anticonvulsant activity ofthese compounds was evaluated with maximal electroshockseizure test and rotarod test. Among the synthesized compounds,8-octoxy-5-(4H-1,2,4-triazol-4-yl)quinoline (4g)was the most active compound with ED50 of 8.80 mg/kg,TD50 of 176.03 mg/kg and protective index of 20.0. Itsneurotoxicity was lower than all other synthesized compoundsand also markedly lower than that of the referencedrug carbamazepine. In addition, the potency of compound 4gagainst seizures induced by pentylenetetrazole, 3-mercaptopropionicacid, and bicuculline suggested its broad spectrumactivity, and the mechanisms of action including inhibition ofvoltage-gated ion channels and modulation of GABAergicactivity might involve in its anticonvulsant activity.

Secure Convertible Undeniable Signature Scheme Using Extended Euclidean Algorithm without Random Oracles

( Shi-jinn Horng ),( Shiang-feng Tzeng ),( Pingzhi Fan ),( Xian Wang ),( Tianrui Li ),( Muhammad Khurram Khan ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.6

A convertible undeniable signature requires a verifier to interact with the signer to verify a signature and furthermore allows the signer to convert a valid one to publicly verifiable signature. In 2007, Yuen et al. proposed a convertible undeniable signature without random oracles in pairings. However, it is recently shown that Yuen et al.`s scheme is not invisible for the standard definition of invisibility. In this paper, we propose a new improvement by using extended Euclidean algorithm that can overcome the visibility attack. The proposed scheme has been evaluated based on computation and communication complexities and the performance comparisons of Yuen et al.`s scheme and various convertible undeniable signature schemes are provided. Moreover, it has been observed that the proposed algorithm reduces the computation and communication times significantly.

A High-Current RFQ Accelerator for the ADS System in China

Shi-Nian Fu,Shou-Xian Fang,Xia-Ling Guan 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.4

An intense-beam Radio Frequency Quadrupole (RFQ) accelerator is under construction at Institute of High Energy Physics (IHEP), Beijing. It accelerates a proton beam with an average current of 3mA at a 6 % duty factor to 3.5 MeV from 75 keV. This four-vane type 352-MHz RFQ has a length of 4.7m and is separated into two resonantly coupled segments. This paper will present the physics design and the technology development of the RFQ, including the beam dynamics design study, the measurement of cold models, quadrupole and dipole field tuning of the long cavity, and the RF power source system. Now, the RFQ is being installed, and the beam tuning will start in 2006.

Separating machining errors of S-shaped samples based on the comprehensive error field of five-axis machine tools

Shi Wu,Yupeng Wang,Xian-li Liu,Zhengdong Fan,Tai Yu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.1

In the present study, a new method is proposed to separate machining errors of a 5-axis machine tool with a double turntable. Moreover, a high-precision compensation model is established to calculate machining errors of thin-walled parts in a 5-axis machine tool. In this regard, a comprehensive error model of the S-shaped sample part considering geometric, thermal, and machining errors is established. Then based on the homogeneous transformation matrix, the geometric error models of translational axes and the A and C axes of the rotation axis are established. Accordingly, geometric errors of each motion axes are identified and measured. Meanwhile, the thermal error of the spindle is measured, and the thermal error model of the machine tool along X/Y/Z directions is established using the multiple linear regression method. Finally, the S-shaped sample is processed and the on-machine measurement of the sample surface is carried out. Based on the obtained machining error from the separation method, the distribution of the total surface error at different curvatures of the S-shaped sample is analyzed, and the distributions of geometric and thermal errors of the machine tool are obtained. It is found that when the geometric and thermal errors of the machine tool are compensated, the measured machining error of each point of the S-shaped sample can be reduced by 10-15 μm compared with that before compensation.

Influence of LPPS Spraying Parameters on Deposition Efficiency of Zirconia Powder

Shi, Jian-Min,Hu, Zhong-Yin,Huang, Jing-Qi,Ding, Chuan-Xian The Korean Vacuum Society 1997 Applied Science and Convergence Technology Vol.6 No.1

Yttria stabilized zirconia coating is an attractive material for several engineering applications. In order to produce coatings with consistent and reliable performance it is important to understand the influence of spraying parameters on the coating properties and optimize the spraying parameters. In this paper the low pressure plasma spray(LPPS) deposition of as-received zirconia powder has been investigated using simple one-factor-at-a-time approach. The deposition efficiency was chosen to evaluate the melting characteristics of the as-received zirconia powder. The results obtained indicated that the deposition efficiency of zirconia powder is very sensitive to the spraying parameters such as plasma gas flow rate and ranges from 24% to 57% The microstructure and the phase composition of zirconia coating deposited with the different plasma spraying parameters were also examined by SEM and XRD respectively. The relationship between deposition efficiency and the microstructure of zirconia coating was discussed.