Longitudinal Dynamic Response of Pile Foundation in a Nonuniform Initial Strain Field

Xiaojun Tian,Wentao Hu,Xiaonan Gong 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.6

This paper presents an investigation into the dynamic response of pile and soil due to pile installation in a radially inhomogeneous initial strain field. The radial variation rule for the shear modulus and physical parameters of the soil caused by the initial strain field is deduced. On the basis of the plane strain and complete P-S (pile-soil) contact assumptions, the analytical solution of longitudinal dynamic impedance of the soil is derived by means of subdividing the soil domain into a number of annular vertical zones. The longitudinal impedance of the pile top and velocity response in frequency and time domains, are also obtained. The parametric study of interfacial pressure on the dynamic response of P-S system is undertaken within a relatively lower frequency domain. Comparison results between previous solutions and the present study indicates that the analytical solution derived in this paper is more stable.

Light-induced negative differential resistance effect in a resistive switching memory device

Xiaojun Wang,Yuanyang Wang,Ming Feng,Kaiyue Wang,Pinbo Bai,Yuming Tian 한국물리학회 2020 Current Applied Physics Vol.20 No.3

The negative differential resistance (NDR) effect was observed in a Pt/BiFeO3/TiO2/BiFeO3/Pt memory cell by using light-illumination as extra stimulation. Further, the coexistence appearances and gradually becomes obvious when the device is exposed to light-illumination, which display an excellent stability and reversibility of the coexistence of NDR and resistive switching (RS) at room temperature. Through analysis of the physical conduction mechanism, it is expected that a large number of photo-generated charge carriers are induced under light-illumination on the surface and interface of the heterojunction is responsible for the appearance of this coexistence phenomenon. Importantly, the NDR effect is strengthened by the competition transfer of charge carrier in the polarized electric field under light-illumination. This work shows that the coexistence of lightmodulated NDR and RS can deeply explore the potential applications of light-controlled multifunctional devices.

Equilibrium, kinetic and mechanism studies on the biosorption of Cu2+ and Ni2+ by sulfur-modified bamboo powder

Tian Ai,Xiaojun Jiang,Hongmei Yu,Hong-Bo Xu,Dawei Pan,Qingyu Liu,Dongyu Chen,Jinyang Li 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.2

Two biosorbents were prepared using bamboo powder modified with mercaptoacetic acid and carbondisulfide, which exhibits strong adsorption properties for Cu2+ and Ni2+. The obtained materials were characterized byFTIR. Maximum adsorption for both metals was found to occur around pH 5.0-6.5. The kinetic data followed thepseudo-second-order model. The maximum adsorption capacities of Cu2+ and Ni2+ on mercaptoacetic acid modifiedbamboo powder determined from Langmuir isotherm were 103.97mg g−1 and 61.35mg g−1, respectively. While oncarbon disulfide modified bamboo powder were 128.21mg g−1 and 56.82mg g−1, respectively. The adsorption mechanismanalysis revealed that the most possible adsorption mode of Cu2+ was coordination, and Ni2+ was ion exchange. The obtained adsorbents could effectively remove Cu2+ and Ni2+ from industrial electroplating wastewater and could beused repeatedly for more than five cycles.

Antiviral effects of Bovine antimicrobial peptide against TGEV in vivo and in vitro

Xiuli Liang,Xiaojun Zhang,Kaiqi Lian,Xiuhua Tian,Mingliang Zhang,Shiqiong Wang,Cheng Chen,Cunxi Nie,Yun Pan,Fangfang Han,Zhanyong Wei,Wen-Ju Zhang 대한수의학회 2020 Journal of Veterinary Science Vol.21 No.5

Background: In suckling piglets, transmissible gastroenteritis virus (TGEV) causes lethal diarrhea accompanied by high infection and mortality rates, leading to considerable economic losses. This study explored methods of preventing or inhibiting their production. Bovine antimicrobial peptide-13 (APB-13) has antibacterial, antiviral, and immune functions. Objectives: This study analyzed the efficacy of APB-13 against TGEV through in vivo and in vitro experiments. Methods: The effects of APB-13 toxicity and virus inhibition rate on swine testicular (ST) cells were detected using 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT). The impact of APB-13 on virus replication was examined through the 50% tissue culture infective dose (TCID50). The mRNA and protein levels were investigated by real-time quantitative polymerase chain reaction and western blot (WB). Tissue sections were used to detect intestinal morphological development. Results: The safe and effective concentration range of APB-13 on ST cells ranged from 0 to 62.5 μg/mL, and the highest viral inhibitory rate of APB-13 was 74.1%. The log10TCID50 of 62.5 μg/mL APB-13 was 3.63 lower than that of the virus control. The mRNA and protein expression at 62.5 μg/mL APB-13 was significantly lower than that of the virus control at 24 hpi. Piglets in the APB-13 group showed significantly lower viral shedding than that in the virus control group, and the pathological tissue sections of the jejunum morphology revealed significant differences between the groups. Conclusions: APB-13 exhibited good antiviral effects on TGEV in vivo and in vitro.

Comparison of the activities of photosystem II of four table grapevine cultivars during high-temperature stress

Qian Zha,Xiaojun Xi,Aili Jiang,Yihua Tian 한국원예학회 2018 Horticulture, Environment, and Biotechnology Vol.59 No.3

High-temperature stress influences the growth and development of grapevines, and plant responses to this stress vary between laboratory and natural conditions. In the present study, the responses to high-temperature stress in four grapevine cultivars (‘Summer Black’, ‘Zuijinxiang’, ‘Hupei1#’, and ‘Shenfeng’) were studied by comparing chlorophyll a fluorescence and the levels of heat-shock protein 21 (HSP21) after exposure to control (35 °C in controlled laboratory conditions or at 37 °C in a greenhouse with naturally fluctuating temperatures) and high-temperature stress treatments (45 °C in laboratory conditions or 42 °C in the field conditions). Leaf water loss in ‘Summer Black’ was less than that in the three other cultivars after treatment at 45 °C. Some parameters (ΨEo, Wk, RCQA, and Mo) of photosystem II (PSII) activity were altered in ‘Shenfeng’, ‘Zuijinxiang’, and ‘Hupei1#’, but were unaltered in ‘Summer Black’ after treatment at 45 °C. Other parameters (maximum photochemical efficiency (Fv/Fm), performance index on absorption basis (PIABS), ΦPo, ΦEo, and HSP21 levels) were altered in ‘Summer Black’, but to a lesser extent than in the three other cultivars under high-temperature stress. Unlike ‘Summer Black’, extreme injury owing to leaf water loss to ‘Shenfeng’, ‘Zuijinxiang’, and ‘Hupei1#’ could be explained by disruption of PSII activity. Furthermore, there were the observed differences in PSII activity between in laboratory and field conditions, which could be considered as the mechanisms for high-temperature acclimation and other environment factors.

Refining Characteristics of Hardwood Pulp Using Straight- and Curved-bar Plates: A Time Series Study

Huan Liu,Jixian Dong,Xiaojun Jiang,Chong Luo,Xiaohui Tian,Ruifang Yang,Litao Zhang,Bo Wang,Yan Yan 한국펄프·종이공학회 2019 펄프.종이기술 Vol.51 No.5

There are obvious differences in the refining characteristics of plates with straight bars compared to curved bar plates having the same bar parameters during refining. The objective of this research is to explore the difference in the refining characteristics of the straight bar and curved bar plates on experimental and theoretical studies. The bar angle of the curved bar plate is defined, and the two plates are used in the refining of bleached sulphate eucalyptus pulp (BSEP). Samples at different refining times were collected, and the properties of the fibers, pulp, and paper were detected and analyzed. It was found that the curved bar and straight bar plates have a similar influence on the pulp SR freeness. However, the curved bar plate effectively retained the fiber length, which means that its fiber cutting effect is weaker than that of the straight bar plate. Meanwhile, the fiber external fibrillation of the samples refined by the curved bar plate was better than that of the samples refined by the straight bar, which showed a higher tensile and tear index of the formed paper. Through the theoretical analysis of refining intensity via characterization of the parameter bar edge length (BEL), the specific edge load (SEL) of the curved bar plate was lower, and the refining characteristics predicted by the refining intensity were similar to the results from the experiments conducted in this paper.

Variation of sexual dimorphism and asymmetry in disease expression of inflammatory arthritis among laboratory mouse models with different genomic backgrounds

Wei Dong,Cheng Tian,Z. Galvin Li,David Brand,Yanhong Cao,Xiaoyun Liu,Jiamin Ma,Andy Chai,LindaK.myers,Jian Yan,Karen Hasty,John Stuart,Yan Jiao,Weikuan Gu,Xiaojun Cai 한국실험동물학회 2023 Laboratory Animal Research Vol.39 No.4

Sex difference has shown in the arthritis diseases in human population and animal models. We investigate how the sex and symmetry vary among mouse models with different genomic backgrounds. Disease data of sex and limbs accumulated in the past more than two decades from four unique populations of murine arthritis models were analyzed. They are (1) interleukin-1 receptor antagonist (IL-1ra) deficient mice under Balb/c background (Balb/c KO); (2) Mice with collagen II induced arthritis under DBA/1 background; (3) Mice with collagen II induced arthritis under C57BL/6 (B6) background and (4) A F2 generation population created by Balb/c KO X DBA/1 KO. Our data shows that there is a great variation in sexual dimorphism for arthritis incidence and severity of arthritis in mice harboring specific genetic modifications. For a F2 population, the incidence of arthritis was 57.1% in female mice and 75.6% in male mice. There was a difference in severity related to sex in two populations: B6.DR1/ B6.DR4 (P < 0.001) and F2 (P = 0.023) There was no difference Balb/c parental strain or in collagen-induced arthritis (CIA) in DBA/1 mice. Among these populations, the right hindlimbs are significantly higher than the scores for the left hindlimbs in males (P < 0.05). However, when examining disease expression using the collagen induced arthritis model with DBA/1 mice, sex-dimorphism did not reach statistical significance, while left hindlimbs showed a tendency toward greater disease expression over the right. Sexual dimorphism in disease expression in mouse models is strain and genomic background dependent. It sets an alarm that potential variation in sexual dimorphism among different racial and ethnic groups in human populations may exist. It is important to not only include both sexes and but also pay attention to possible variations caused by disease expression and response to treatment in all the studies of arthritis in animal models and human populations.

An Optimal Combined SVM Model for Short-term Wind Speed Forecasting

Bai, Dan-Dan,He, Jing-Han,Tian, Wen-Qi,Wang, Xiaojun,Tony, Yip 대한전기학회 2014 The Journal of International Council on Electrical Vol.4 No.4

A high precise wind speed forecasting method is one of current wind power research hotspots. This paper presented a combined wind speed forecasting model based on support vector machine (SVM) optimized by particle swarm optimization (PSO) using historical data of wind speed at the site. The model took the results of back propagation neural network (BPNN), radial basis function neural network (RBFNN), genetic neural network (GNN) and wavelet neural network (WNN) as the inputs, and adopted the actual wind speed as the output. Meanwhile, particle swarm optimization was used to optimize model parameters. Apply this model in hourly prediction of wind speed using historical data from a wind farm in Shanxi Province. It is observed that its prediction accuracy was not only higher than that of any of its single network but higher than traditional linear combined forecasting model and neural network combined forecasting model.

Study on Fiber Cutting Performance of Isometric Straight Bar Plate with Different Bar Angle

Huan Liu,Jixian Dong,Xiya Guo,Chong Luo,Xiaohui Tian,Xiaojun Jiang,Sha Wang,Ruifan Yang,Chuanwu Duan,Bo Wang,Kai Qi 한국펄프·종이공학회 2019 펄프.종이기술 Vol.51 No.5

The refining plate is a direct-acting component of refiners in pulping, and the bar profile of it have a major impact on fiber cutting, which affects the paper forming and strength of the formed paper. In this paper, the fiber average length, the fiber length distribution, the original fiber cutting rate and adjacent fiber cutting rate of samples collected in different refining time are used to analyze the fiber cutting mechanism of the isometric straight bar refining plates with different bar angles. The results show that the fiber cutting performance of plates gradually decreases and the limit fiber cutting length of the plate increases with the increase of the bar angle which is opposite to the conclusion predicted by specific edge load (SEL). However, the fiber cutting action of plates is gradually weakened until the average fiber length is reduced to the limit cutting length of plates. Meanwhile, the cutting mechanism of the straight bar plates with different bar angles is different. The larger bar angle of plate, the lower fiber cutting rate and the adjacent cutting rate of which is basically kept constant during refining, while the adjacent cutting rate of smaller bar angle plate on fibers gradually decreases with refining and finally remains constant. The study on the cutting performance of different bar angle plates has positive significance for the selection and design of refining plates for different pulping process.

Template-assisted preparation of metal-modified SAPO-34 molecular sieves for the catalysis of methanol-to-olefins

Jihui Yao,Jiapeng Jiao,Ruiqiang Liu,Fei Zha,Xiaojun Guo,Xiaohua Tang,Haifeng Tian,Yue Chang 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.7

To improve the dispersion of metals and to enhance the catalytic performance of SAPO-34 molecular sieves, the template-assisted method was applied to synthesize Co, Ni and Zn modified SAPO-34 molecular sieves by using palygorskite as silicon source and tetraethylammonium hydroxide as template. The metal modified SAPO-34 molecular sieves were characterized by XRD, SEM, XPS, N2-adsorption-desorption, NH3-TPD, FTIR, ICP-AES and TG. The N atoms of tetraethylammonium hydroxide exhibited the different forces to three metal ions, thus the acidity of the molecular sieves was further regulated. Compared with metal modified SAPO-34 molecular sieves prepared by impregnation, metal modified SAPO-34 molecular sieves prepared by template-assisted maintained higher surface area, bigger pore volume and better dispersion of metals. The catalytic performance of metal modified SAPO-34 molecular sieves prepared by template-assisted method in the reaction of methanol-to-olefins (MTO) was investigated in the fixed bed reactor. Under the reaction conditions that the reaction temperature was 400 oC, the reaction pressure was 0.1 MPa, the feed WHSV was 2.0 h1 and the mass of catalyst was 0.5 g, Ni modified SAPO-34 molecular sieves exhibited great methanol conversion and high selectivity to light olefins. The selectivity of light olefins reached 95.7%.