Dynamic Instability Analysis of Axially Compressed Castellated Columns

Jin-song Lei,Boksun Kim,Long-yuan Li 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.2

This paper presents an analytical study on the dynamic instability of castellated columns subjected to axial excitation loading. By assuming the instability modes, the kinetic energy and strain energy of the columns and the loss of the potential of the axially applied load are evaluated, from which the mass matrix, stiffness matrix, and geometric stiffness matrix of the system are derived. These matrices are then used for deriving dynamic equations and carrying out the analysis of dynamic instability of castellated columns by using Bolotin’s method. The analytical expression for determining the critical excitation frequency of the columns is derived, which takes account for not only the shear influence of web openings but also the rotary inertia effect on the transverse vibration of the columns. Numerical examples are also provided for illustrating the dynamic instability behaviour of castellated columns when subjected to axial excitation loading. The results show that the consideration of the shear effect in castellated columns results in a shaft of the dynamic instability zone to low frequency side and a reduction of the width of the dynamic instability zone. The shear effect on the dynamic instability zone becomes more significant in the short column than in the long column, and in the wide flange column than in the narrow flange column.

Experimental Studies on Bond Performance of BFRP Bars Reinforced Coral Aggregate Concrete

Lei Wang,Zhaoping Song,Jin Yi,Jiayi Li,Feng Fu,Kai Qian 한국콘크리트학회 2019 International Journal of Concrete Structures and M Vol.13 No.7

Basalt fiber reinforced polymer (BFRP) rebars reinforced coral aggregate concrete is a new type of concrete used in ocean engineering. In order to investigate the bond performance between BFRP rebars and coral concrete, 30 pullout tests were carried out in 10 groups with different diameters of BFRP rebars, bonding lengths and strength of the coral concrete. The results show that good bonding between BFRP rebars and coral concrete were achieved. The main failure modes can be categorized as BFRP rebars pull out destruction, splitting failure of coral concrete and BFRP rebars fracture. The bond slip ( τ -s ) curves of the BFRP rebars and coral concrete were obtained during the tests. It was found to be similar to the common concrete using fiber reinforced polymer (FRP) bars. The bond-slip relation can be roughly divided into micro-slip phase, slip phase, decline phase, and the residual stress stage. The bond between BFRP rebars and coral concrete increases with the increase of the bond length and diameter of BFRP rebars, but the average bond stress will decrease. Moreover, increasing the strength of coral concrete is effective to improve the bond performance of BFRP rebars. In this paper, the continuous bond slip model (Gao et al. in J Zhengzhou Univ 23:1.5, 2002) was used to represent the τ -s constitutive relationship of BFRP rebars and coral concrete. The analysis show that the proposed model has a high degree of accuracy in representing τ -s curve of BFRP rebars and coral concrete.

Optogenetics reveals a role for accumbal medium spiny neurons expressing dopamine D2 receptors in cocaine-induced behavioral sensitization

Song, Shelly Sooyun,Kang, Byeong Jun,Wen, Lei,Lee, Hyo Jin,Sim, Hye-ri,Kim, Tae Hyong,Yoon, Sehyoun,Yoon, Bong-June,Augustine, George J.,Baik, Ja-Hyun Frontiers Media S.A. 2014 Frontiers in Behavioral Neuroscience Vol.8 No.-

<P>Long-lasting, drug-induced adaptations within the nucleus accumbens (NAc) have been proposed to contribute to drug-mediated addictive behaviors. Here we have used an optogenetic approach to examine the role of NAc medium spiny neurons (MSNs) expressing dopamine D2 receptors (D2Rs) in cocaine-induced behavioral sensitization. Adeno-associated viral vectors encoding channelrhodopsin-2 (ChR2) were delivered into the NAc of D2R-Cre transgenic mice. This allowed us to selectively photostimulate D2R-MSNs in NAc. D2R-MSNs form local inhibitory circuits, because photostimulation of D2R-MSN evoked inhibitory postsynaptic currents (IPSCs) in neighboring MSNs. Photostimulation of NAc D2R-MSN <I>in vivo</I> affected neither the initiation nor the expression of cocaine-induced behavioral sensitization. However, photostimulation during the drug withdrawal period attenuated expression of cocaine-induced behavioral sensitization. These results show that D2R-MSNs of NAc play a key role in withdrawal-induced plasticity and may contribute to relapse after cessation of drug abuse.</P>

A Hyper-cross-linked Polynaphthalene Semiconductor with Excellent Visible-Light Photocatalytic Performance in the Degradation of Organic Dyes

Zhang, Lei,Huang, Xin-Hua,Hu, Jin-Song,Song, Jian,Kim, Il American Chemical Society 2017 Langmuir Vol.33 No.8

<P>Hyper-cross-linked polynaphthalene nanoparticles (PNNs) capable of catalyzing the degradation of organic pollutants upon exposure to visible light have been developed. The nascent and metal-free PNNs with a porous structure, high specific surface area, and narrow bandgap are chemically and thermally stable in the catalytic system, which make it promising as a kind of excellent photocatalytic material compared to conventional photocatalysts. The photo catalytic activity of the as-obtained PNNs exhibits remarkable photocatalytic perforniance for the degradation of rhodamine B (RhB) and methyl blue (MB) under the irradiation of visible light. The easy preparation,, high catalytic activity, and recyclability of the PNNs open new opportunities in the visible-light promoted degradation of organic pollutants.</P>

Smart Subway Information Platform based on Internet of Things

Jun-Song Fu,Zhen-Jiang Zhang,Xin-Lei Jin,Zi-Qi Hao 보안공학연구지원센터 2013 International Journal of Hybrid Information Techno Vol.6 No.6

Emulsified oil foam for improving the flowability of heavy oil in wellbore under high salinity environments

Fa-yang Jin,Song Wang,Wan-Fen Pu,Cheng-dong Yuan,Lei Wang,Ke-xing Li,Can Gong 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.39 No.-

Emulsified oil foam was investigated to improve the flowability of heavy oil under high salinityenvironment of 23 104 mg/L. Sixteen foaming agents were used to determine an applicableformulation. The factors affecting the formation and stability of the emulsified oil foam were evaluated,including oil viscosity, oil–water ratio, foaming agent concentration, stirring rate and time, andtemperature. The microgram of emulsified oil foam was analyzed by polarizing microscope. The resultsshowed that stable pseudo-emulsion film was built. The considerable dynamic viscosity-reducing ratesin different depth in wellbore were obtained according to pressure differential method in long tubephysical simulation experiments.

Geometry Characteristics Prediction of Single Track Cladding Deposited by High Power Diode Laser Based on Genetic Algorithm and Neural Network

Huaming Liu,Xunpeng Qin,Song Huang,Lei Jin,Yongliang Wang,Kaiyun Lei 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.7

This paper aims to establish a correlation between the process parameters and geometrical characteristics of the sectional profile of the single track cladding deposited by high power diode laser with rectangle beam spot. By applying the genetic algorithm and back propagation neural network, a nonlinear model for predicting the geometry features of the single track cladding is developed. A full factorial design method is used to conduct the experiments, and the experimental results are chosen randomly as training dataset and testing dataset for the neural network. Three main input variables such as laser power, scanning speed, and powder thickness were considered. The performance of the genetic algorithm and back propagation artificial neural network was compared to that of the standard back propagation neural network. To improve the accuracy of the neural network, one-hidden-layer and double-hidden-layer neural network with different architectures were performed. Further, one-output and multi-output neural network are also trained and tested. The results indicate that, by using genetic algorithm, the prediction accuracy of the neural network is significantly improved. Meanwhile, the double-hidden-neural network has higher prediction accuracy than the one-hidden-layer-neural network, while the one-output-neural network has higher prediction accuracy than the multi-output-neural network.

Variants on ESR1 and their Association with Prostate Cancer Risk: A Meta-analysis

Ding, Xiang,Cui, Feng-Mei,Xu, Song-Tao,Pu, Jin-Xian,Huang, Yu-Hua,Zhang, Jiang-Lei,Wei, Xue-Dong,Hou, Jian-Quan,Yan, Chun-Yin Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8

Background: Epidemiological studies evaluating the association of two variants rs9340799 and rs2234693 on estrogen receptor 1 (ESR1) with prostate risk have generated inconsistent results. Methods: A meta-analysis was here conducted to systematically evaluate the relationship of these two variants with prostate cancer susceptibility. Results: For rs9340799, heterozygosity of T/C carriers showed a significant increased prostate cancer risk with a pooled odds ratio (OR) of 1.34 (95% CI = 1.06-1.69) while homozygote C/C carriers showed an increased but not statistically significant association with prostate cancer risk (pooled OR = 1.29, 95% CI = 0.94-1.79). Compared to the homozygous TT carriers, the allele C carriers showed a 31% increased risk for prostate cancer (pooled OR = 1.31, 95% CI = 1.06-1.63). No significant association between the rs2234693 and prostate cancer risk was found with the pooled OR of 1.15 (95% CI = 0.97-1.39, T/C and C/C vs. T/T) under the dominant genetic model. Compared to the homozygote T/T carriers, the heterozygous T/C carriers did not show any significantly different risk of prostate cancer (pooled OR = 1.13, 95% CI = 0.94-1.36) and the homozygous C/C carriers also did not show a significant change for prostate cancer risk compared to the wide-type T/T carriers (pooled OR = 1.26, 95% CI = 0.98-1.62). Conclusion: These data suggested that variant rs9340799, but not rs2234693, on ESR1 confers an elevated risk of prostate cancer.

Halomonas alkalitolerans sp. nov., a Novel Moderately Halophilic Bacterium Isolated from Soda Meadow Saline Soil in Daqing, China

Shuang Wang,Qian Yang,Zhi-Hua Liu,Lei Sun,Dan Wei,Jun-Zheng Zhang,Jin-Zhu Song,Yun Wang,Jia Song,Jin-Xia Fan,Xian-Xin Meng,Wei Zhang 한국미생물학회 2011 The journal of microbiology Vol.49 No.1

A moderately halophilic bacterial strain 15-13^T, which was isolated from soda meadow saline soil in Daqing City, Heilongjiang Province, China, was subjected to a polyphasic taxonomic study. The cells of strain 15-13^T were found to be Gram-negative, rod-shaped, and motile. The required growth conditions for strain 15-13^T were: 1-23% NaCl (optimum, 7%), 10-50°C (optimum, 35°C), and pH 7.0-11.0 (optimum, pH 9.5). The predominant cellular fatty acids were C18:1 ω7c (60.48%) and C16:0 (13.96%). The DNA G+C content was 67.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparisons indicated that strain 15-13^T clustered within a branch comprising species of the genus Halomonas. The closest phylogenetic neighbor of strain 15-13^T was Halomonas pantelleriensis DSM 9661^T (98.9% 16S rRNA gene sequence similarity). The level of DNA-DNA relatedness between the novel isolated strain and H. pantelleriensis DSM 9661^T was 33.8%. On the basis of the phenotypic and phylogenetic data, strain 15-13^T represents a novel species of the genus Halomonas, for which the name Halomonas alkalitolerans sp. nov. is proposed. The type strain for this novel species is 15-13^T (=CGMCC 1.9129^T =NBRC 106539^T).

Soy Protein Isolate As Fluid Loss Additive in Bentonite–Water-Based Drilling Fluids

Li, Mei-Chun,Wu, Qinglin,Song, Kunlin,Lee, Sunyoung,Jin, Chunde,Ren, Suxia,Lei, Tingzhou American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.44

<P>Wellbore instability and formation collapse caused by lost circulation are vital issues during well excavation in the oil industry. This study reports the novel utilization of soy protein isolate (SPI) as fluid loss additive in bentonite–water based drilling fluids (BT-WDFs) and describes how its particle size and concentration influence on the filtration property of SPI/BT-WDFs. It was found that high pressure homogenization (HPH)-treated SPI had superior filtration property over that of native SPI due to the improved ability for the plugging pore throat. HPH treatment also caused a significant change in the surface characteristic of SPI, leading to a considerable surface interaction with BT in aqueous solution. The concentration of SPI had a significant impact on the dispersion state of SPI/BT mixtures in aquesous solution. At low SPI concentrations, strong aggregations were created, resulting in the formation of thick, loose, high-porosity and high-permeability filter cakes and high fluid loss. At high SPI concentrations, intercatlated/exfoliated structures were generated, resulting in the formation of thin, compact, low-porosity and low-permeability filter cakes and low fluid loss. The SPI/BT-WDFs exhibited superior filtration property than pure BT-WDFs at the same solid concentraion, demonstrating the potential utilization of SPI as an effective, renewable, and biodegradable fluid loss reducer in well excavation applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2015/aamick.2015.7.issue-44/acsami.5b07883/production/images/medium/am-2015-07883j_0012.gif'></P>