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Topographic Evolution around Twin Piers in a Tandem Arrangement
Hao Wang,Hongwu Tang,Quanshuai Liu,Xuanyu Zhao 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.7
This laboratory study investigates the 2-D topographic evolution of a sand bed with cylindrical bridge piers arranged in tandem. The results of clear-water scouring experiments around two piers show that shapes of topography were similar for different spacing and scour duration. Fractal theory and statistical analysis were used to estimate the statistical properties of the evolution of the sandbed topography around the piers. The statistical properties of the bed surface contours remained almost stationary under continuing scouring action. Finally, the difference of local scour depth between two piers with scour time can be segregated into three regions: sheltering region, co-effect region and stabilizing region.
Optimal placement of piezoelectric curve beams in structural shape control
Wang, Jian,Zhao, Guozhong,Zhang, Hongwu Techno-Press 2009 Smart Structures and Systems, An International Jou Vol.5 No.3
Shape control of flexible structures using piezoelectric materials has attracted much attention due to its wide applications in controllable systems such as space and aeronautical engineering. The major work in the field is to find a best control voltage or an optimal placement of the piezoelectric actuators in order to actuate the structure shape as close as possible to the desired one. The current research focus on the investigation of static shape control of intelligent shells using spatially distributed piezoelectric curve beam actuators. The finite element formulation of the piezoelectric model is briefly described. The piezoelectric curve beam element is then integrated into a collocated host shell element by using nodal displacement constraint equations. The linear least square method (LLSM) is employed to get the optimum voltage distributions in the control system so that the desired structure shape can be well matched. Furthermore, to find the optimal placement of the piezoelectric curve beam actuators, a genetic algorithm (GA) is introduced in the computation model as well as the consideration of the different objective functions. Numerical results are given to demonstrate the validity of the theoretical model and numerical algorithm developed.
Optimal placement of piezoelectric curve beams in structural shape control
Jian Wang,Guozhong Zhao,Hongwu Zhang 국제구조공학회 2009 Smart Structures and Systems, An International Jou Vol.5 No.3
Shape control of flexible structures using piezoelectric materials has attracted much attention due to its wide applications in controllable systems such as space and aeronautical engineering. The major work in the field is to find a best control voltage or an optimal placement of the piezoelectric actuators in order to actuate the structure shape as close as possible to the desired one. The current research focus on the investigation of static shape control of intelligent shells using spatially distributed piezoelectric curve beam actuators. The finite element formulation of the piezoelectric model is briefly described. The piezoelectric curve beam element is then integrated into a collocated host shell element by using nodal displacement constraint equations. The linear least square method (LLSM) is employed to get the optimum voltage distributions in the control system so that the desired structure shape can be well matched. Furthermore, to find the optimal placement of the piezoelectric curve beam actuators, a genetic algorithm (GA) is introduced in the computation model as well as the consideration of the different objective functions. Numerical results are given to demonstrate the validity of the theoretical model and numerical algorithm developed.
Hong Wu,Ruhui Li,XiaoDong Hang,Ming Yan,Feng Niu,Lidi Liu,Wei Liu,Song Zhao,Shaokun Zhang 한국유방암학회 2011 Journal of breast cancer Vol.14 No.3
Purpose: To investigate the distribution of CD44+/CD24- cells in breast cancers in relation to tumor size before and after the administration of neoadjuvant chemotherapy. Methods: CD44+/CD24- tumor cells obtained from breast cancer specimens were characterized in vivo and in vitro using tumor formation assays and mammosphere generation assays, respectively. The distribution of CD44+/CD24- tumor cells in 78 breast cancer specimens following administration of neoadjuvant chemotherapy was also evaluated using immunofluorescence assays, and this distribution was compared with the extent of tumor invasion predicted by Response Evaluation Criteria in Solid Tumours (RECIST). Results: In 27/78 cases, complete remission (CR) was identified using RECIST. However, 18 of these CR cases were associated with a scattered distribution of tumor stem cells in the outline of the original tumor prior to neoadjuvant chemotherapy. After neoadjuvant chemotherapy, 24 cases involved cancer cells that were confined to the tumor outline, and 21 cases had tumor cells or tumor stem cells overlapping the tumor outline. In addition, there were 6 patients who were insensitive to chemotherapy, and in these cases, both cancer cells and stem cells were detected outside the contours of the tumor volume imaged prior to chemotherapy. Conclusion:CD44+/CD24- tumor cells may be an additional parameter to evaluate when determining the extent of breast cancer invasion.