Analysis of restrained steel beams subjected to heating and cooling Part II: Validation and parametric studies

Shi-Xiong Guo,Guo-Qiang Li 국제구조공학회 2008 Steel and Composite Structures, An International J Vol.8 No.1

This paper presents the results of a validation and parametric study for the theory presented in the companion paper. The parameters investigated include the stiffness of axial and rotational restraints, load ratio, depth-span ratio of the beam, the yield strength of steel, load type and the temperature distribution in the crosssection of the beam.

Analysis of restrained steel beams subjected to heating and cooling Part I: Theory

Guo-Qiang Li,Shi-Xiong Guo 국제구조공학회 2008 Steel and Composite Structures, An International J Vol.8 No.1

Observations from experiments and real fire indicate that restrained steel beams have better fireresistant capability than isolated beams. Due to the effects of restraints, a steel beam in fire condition can undergo very large deflections and the run away damage may be avoided. In addition, axial forces will be induced with temperature increasing and play an important role on the behaviour of the restrained beam. The factors influencing the behavior of a restrained beam subjected to fire include the stiffness of axial and rotational restraints, the load type on the beam and the distribution of temperature in the cross-section of the beam, etc. In this paper, a simplified model is proposed to analyze the performance of restrained steel beams in fire condition. Based on an assumption of the deflection curve of the beam, the axial force, together with the strain and stress distributions in the beam, can be determined. By integrating the stress, the combined moment and force in the cross-section of the beam can be obtained. Then, through substituting the moment and axial force into the equilibrium equation, the behavior of the restrained beam in fire condition can be worked out. Furthermore, for the safety evaluation and repair after a fire, the behaviour of restrained beams during cooling should be understood. For a restrained beam experiencing very high temperatures, the strength of the steel will recover when temperature decreases, but the contraction force, which is produced by thermal contraction, will aggravate the tensile stresses in the beam. In this paper, the behaviour of the restrained beam in cooling phase is analyzed, and the effect of the contraction force is discussed.

Analysis of restrained heated steel beams during cooling phase

Guo-Qiang Li,Shi-Xiong Guo 국제구조공학회 2009 Steel and Composite Structures, An International J Vol.9 No.3

Observations from experiments and real fire indicate that restrained steel beams have better fireresistant capability than isolated beams. Due to the effects of restraints, a steel beam in fire condition can undergo very large deflections and the run away damage may be avoided. However disgusting damages may occur in the beam-to-column connections, which is considered to be mainly caused by the enormous axial tensile forces in steel beams resulted from temperature decreasing after fire dies out. Over the past ten years, the behaviour of restrained steel beams subjected to fire during heating has been experimentally and theoretically investigated in detail, and some simplified analytical approaches have been proposed. While the performance of restrained steel beams during cooling has not been so deeply studied. For the safety evaluation and repair of steel structures against fire, more detailed investigation on the behaviour of restrained steel beams subjected to fire during cooling is necessary. When the temperature decreases, the elastic modulus and yield strength of steel recover, and the contraction force in restrained steel beams will be produced. In this paper, an incremental method is proposed for analyzing the behaviour of restrained steel beams subjected to cooling. In each temperature decrement, the development of deformation and internal forces of a restrained beam is divided into four steps, in order to consider the effect of the recovery of the elastic modulus and strength of steel and the contraction force generated by temperature decrease in the beam respectively. At last, the proposed approach is validated by FE method.

Model Identification and Human-robot Coupling Control of Lower Limb Exoskeleton with Biogeography-based Learning Particle Swarm Optimization

Qing Guo,Zhenlei Chen,Yao Yan,Wenying Xiong,Dan Jiang,Yan Shi 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.2

Lower limb exoskeleton is a typical wearable robot to assist human motion and improve physiological power. However, the control performance and stability are affected by some unknown model parameters and control algorithms. Therefore, it is necessary to investigate the model parametric identification and the control design of lower extremity exoskeleton. Firstly, the two degree-of-freedom (DoF) exoskeleton model is constructed by the Lagrange technique. Then the biogeography-based learning particle swarm optimization (BLPSO) is used to optimize the B-spline function parameters and the smooth stimulated trajectories is designed. Meanwhile, the BLPSO is also adopted to identify unknown model parameters of the exoskeleton based on the torques and the joint angles. To decline the negative effect of parametric identification error of exoskeleton, the passive backstepping controller is proposed to improve the tracking performance of human-robot motion. Furthermore, the active admittance controller is adopted to improve the motion comfort of tester. Finally, the comparative experimental results are verified on the platform, which show the BLPSO algorithm has better parametric identification accuracy than PSO and GA. Furthermore, the comparative results have verified that the proposed controller can improve the tracking behavior and reduce the human-robot interaction torque in wearable motion.

AUTONOMOUS LAND VEHICLE PATH PLANNING USING TERRAIN DATABASE

Zhang Shi Bin,Tang Guo Wei,Ma Yue,Zhang Tian Wen,Zhang Shi Xiong 대한전자공학회 1992 대한전자공학회 Conference Vol.1992 No.2

Dimethyl Sulfoxide Suppresses Mouse 4T1 Breast Cancer Growth by Modulating Tumor-Associated Macrophage Differentiation

Rui Deng,Shi-min Wang,Tao Yin,Ting-hong Ye,Guo-bo Shen, Ling Li,Jing-yi Zhao,Ya-xiong Sang,Xiao-gang Duan,Yu-Quan Wei 한국유방암학회 2014 Journal of breast cancer Vol.17 No.1

Purpose: The universal organic solvent dimethyl sulfoxide (DMSO)can be used as a differentiation inducer of many cancer cells andhas been widely used as a solvent in laboratories. However, itseffects on breast cancer cells are not well understood. The aimof this study is to investigate the effect and associated mechanismsof DMSO on mouse breast cancer. Methods: We appliedDMSO to observe the effect on tumors in a mouse breast cancermodel. Tumor-associated macrophages (TAMs) were tested byflow cytometry. Ex vivo tumor microenvironment was imitated by4T1 cultured cell conditioned medium. Enzyme-linked immunosorbentassays were performed to detect interleukin (IL)-10 andIL-12 expression in medium. To investigate the cytotoxicity ofDMSO on TAMs, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assays were performed. Results: We foundthat DMSO produced tumor retardation when injected into mouseperitoneal cavities in a certain concentration range (0.5–1.0 mg/g). Furthermore, as detected by flow cytometry, TAM subtypeswere found to be transformed. We further imitated a tumor microenvironmentin vitro by using 4T1 cultured cell conditionedmedium. Similarly, by using low concentration DMSO (1.0%–2.0% v/v), TAMs were induced to polarize to the classically activatedmacrophage (M1-type) and inhibited from polarizing intothe alternatively activated macrophage (M2-type) in the conditionedmedium. IL-10 expression in tumors was reduced, whileIL-12 was increased compared with the control. Furthermore, wereported that 2.0% (v/v) DMSO could lead to cytotoxicity in peritonealmacrophages after 48 hours in MTT assays. Conclusion:Our findings suggest that DMSO could exert antitumor effects in4T1 cancer-bearing mice by reversing TAM orientation and polarizationfrom M2- to M1-type TAMs. These data may providenovel insight into studying breast cancer immunotherapy.

AUTONOMOUS LAND VEHICLE PATH PLANNING USING TERRAIN DATABASE

Bin, Zhang Shi,Wei, Tang Guo,Yue, Ma,Wen, Zhang Tian,Xiong, Zhang Shi 대한전자공학회 1992 HICEC:Harbin International Conference on Electroni Vol.1 No.1

We describe a new path planning system using terrain database. The system is adapt to the navigation of autonomous land vehicle under known environment such as road network without unknown moving obstacles. We discuss the terrain database structure, terrain representation, global path planning, local path planning under the direction of global path planning.

Human HS1BP3 induces cell apoptosis and activates AP-1

( Tai Ping Shi ),( Jie Shi Xie ),( Ying Xiong ),( Wei Wei Deng ),( Jin Hai Guo ),( Feng Wang ),( Da Long Ma ) 생화학분자생물학회(구 한국생화학분자생물학회) 2011 BMB Reports Vol.44 No.6

In the present study, we characterized the function of HS1-binding protein 3 (HS1BP3), which is mutated in essential tremor and may be involved in lymphocyte activation. We found that HS1BP3 localized to the mitochondria and endoplasmic reticulum partially. Overexpression of HS1BP3 induced apoptosis in HEK293T and HeLa cell lines. When these cell lines were transfected with HS1BP3, they exhibited nuclear DNA condensation, externalization of phosphatidylserine (PS), and cleavage of poly ADP ribose polymerase (PARP). Furthermore, suppression of HS1BP3 or HS1 expression attenuates HS1BP3 induced apoptosis. In addition, HS1BP3 enhanced activator protein 1 (AP-1)-mediated transcription in a dose-dependent manner. Therefore, we conclude that HS1BP3 regulates apoptosis via HS1 and stimulates AP-1-mediated transcription. [BMB reports 2011; 44(6): 381-386]

Diagnosis and Cure Experience of Hepatolithiasis-Associated Intrahepatic Cholangiocarcinoma in 66 Patients

Li, Hong-Yang,Zhou, Shi-Ji,Li, Min,Xiong, Ding,Singh, Akanand,Guo, Qing-Xi,Liu, Chang-An,Gong, Jian-Ping Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.2

Background: The management of hepatolithiasis combined with intrahepatic cholangicarcinoma (IHHCC) remains a challenge due to poor prognosis. The aim of this study was to summarize our diagnosis and cure experience of IHHCC over the recent 10 years. Methods: From January 1996 to January 2006, 66 patients with IHHCC were reviewed retrospectively. Results: Of the 66 patients, 52 underwent surgical resection (radical resection in 38 and palliative in 14) and 8 patients abdominal exploration, while the other 6 cases received endoscopic retrograde biliary internal drainage and stent implantation. In this series, correct diagnosis of advanced stage was made during operation in 8 cases (8/60, 13.3%) and all of them (underwent unnecessary abdominal exploration, among them the positive rate of CA19-9 was 100%, and the positive rate of CEA was 87.6% (7/8), incidence rate of ascites was 100% and short-term significant weight loss was 100%, with median overall survival of only 4 months. Conclusion: Radical resection is mandatory for IHHCC patient to achieve long-term survival, the CT and MR imaging features of IHHCC being concentric enhancement. Patients with IHHCC have significant higher CA199 and significant higher CEA and short-term significant weight loss and ascites should be considered with advanced stage of IHHCC and unnecessary non-therapeutic laparotomies should be avoided.

Regulation of melanocyte apoptosis by Stathmin 1 expression

( Yan Zhang ),( Jiang Jun Xiong ),( Jia Li Wang ),( Xian Ping Shi ),( Guo Dong Bao ),( Yang Zhang ),( Zhen Yu Zhu ) 생화학분자생물학회 2008 BMB Reports Vol.41 No.11