Experimental Studies on Progressive Collapse Behavior of RC Frame Structures: Advances and Future Needs

Wei?Jian Yi,Fan Yi,Yun Zhou 한국콘크리트학회 2021 International Journal of Concrete Structures and M Vol.15 No.4

In the recent two decades, the progressive collapse of reinforced concrete (RC) frame structures attracted unprecedented research interests in the structural engineering community. Experiments are regarded as an essential method in this field since actual cases can barely provide sufficient and effective data to support rigorous research. In this paper, prevailing experimental assumptions and configurations among over 100 series of experiments are quantitatively revealed by a bibliometric collection based on systematic search in an academic database. Since numerous experiments have been reported on the progressive collapse of RC frame structures, this paper subsequently presents a state-of-the-art review summarizing both experimental consensuses and controversies constituted by three main aspects: (a) static mechanisms, (b) dynamic behavior, and (c) threat-dependent research. The significance of secondary mechanisms, existing problems of dynamic effects, and potential flaws of the threat-independent assumption are discussed in detail with experimental findings. Future needs are emphasized on research targets, correlations between experiments and design, dynamic effects, threat-dependent issues, and retrofitting. These recommendations might help researchers or designers realize a more reliable and realistic progressive collapse design of RC frame structures in the future.

Balloon dilation of epidermolysis bullosa-related esophageal strictures: A report of two cases

Wei-Zhong Zhou,Jing-Guo Xia,Zheng-Qiang Yang,Chun-Gao Zhou,Lin-Bo Zhao,Sheng Liu,Hai Bin Shi 소화기인터벤션의학회 2018 International journal of gastrointestinal interven Vol.7 No.3

Epidermolysis bullosa (EB) is a very rare inherited disease featured with skin blistering resulting from minor trauma. Sometimes the esophageal mucosa could also be involved, which leads to esophageal strictures. Here we report two cases of EB-related esophageal strictures who were successfully treated with esophageal balloon dilations. The two cases with EB had severe dysphagia. Clinical examination showed signs of malnutrition, skin blisters and loss of toenails due to EB. They underwent careful fluoroscopic balloon dilation with 10- and 16-mm-sized balloon catheters, respectively. They could ingest soft and some solid foods after the procedure and maintained during the 20 months and 16 months follow-up periods.

Analysis of Non-Prismatic Two-Way Post-Tensioned Slabs

Wei Zhou 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.5

Using a moment-area procedure to analyze slab-beam with step haunches, rotational stiffness, carry over, and fixed-end momentsof a flat slab are formulated for flat slabs with capitals and/or drop panels. Design factors derived are represented in graphical tablesand may be used in the Equivalent Frame Method (EFM) for analyzing and designing two-way post-tensioned slabs. Both ofequivalent prestressing loads: a point load and/or a concentrated moment are evaluated for the stiffer column-slab conjunction regiondue to tensioning prestressing tendons. The results clarify this prestressing equivalent load behavior, and provide a comprehensivebasis of EFM for flat slabs. Compared to a prismatic member, a stiffer column-slab joint region increases the stiffness and carryoverfactor, and influences fixed-end moment of slab under gravity and prestressing loads. The expressions derived for design is availableboth hand-calculation and computer-aided program. A calculation example is given to illustrate the use of current expressions andexisting tables and chart.

The Application and disquisition of Multimedia Technology in MoBlog

Wei ZHOU,Yan-Heng LI 한국멀티미디어학회 2006 한국멀티미디어학회 국제학술대회 Vol.2006 No.-

The appearance of Blog for the first time make us gain an accumulation of knowledge and a direction of culture; they also change human's living pattern from extensive digital one to individual, precise and catalogue one. MoBlog, the Blog used in mobile phone, is a new service based on Blog, mobile phone and wiriness technology. Today mobile communication systems are designed as logically separate networks. They are primarily designed to offer moderate bandwidth to users with wide area coverage (voice and low rate data demands services). The consumer of telecommunication services of tomorrow will expect to receive the same services in a wireless fashion, as he receives from a fixed network. The third generation mobile systems, such as UMTS and IMT-2000, aim at only partially solving these problems. As the extending of the second generation, 3G offers the data-rates, up to 2 M bit/s, but only to a limited number of users in certain areas. In order to enable the use of truly new and innovative multimedia services, 4G communication systems come true, and it adopts OFDM(Orthogonal Frequency Division Multiplexing) system and MIMO(Multiple Input Multiple Output) technology, Experts describe the features of 4G:the emphasis on mobile data; transmitting velocity achieving 100 M bit/s; solving the interruption of electromagnetism; supporting the mutual communication of mobile phone; selecting wore wireless and supporting more abundant mobile services such as high distinct graph and meeting television. The correspondence will be available all over the world with a mobile phone. With the rapid development of 4G, moBlog will be more popular; besides short and simple multimedia messages. Since it is so difficult to input a large quantity of words or browse lots of word contents in a mobile phone. it is more convenient for users to make use of mobile phone's own functions, such as camera and recording set, to transmit messages through multimedia methods, such as photos, audio or video ones. In the future the use of 4G mobile phone will meet people's living needs more.

CONJUGACY SEPARABILITY OF GENERALIZED FREE PRODUCTS OF FINITELY GENERATED NILPOTENT GROUPS

Zhou, Wei,Kim, Goan-Su,Shi, Wujie,Tang, C.Y. Korean Mathematical Society 2010 대한수학회보 Vol.47 No.6

In this paper, we prove a criterion of conjugacy separability of generalized free products of polycyclic-by-finite groups with a non cyclic amalgamated subgroup. Applying this criterion, we prove that certain generalized free products of polycyclic-by-finite groups are conjugacy separable.

Improved Method for Calculating Magnetic Field of Surface-Mounted Permanent Magnet Machines Accounting for Slots and Eccentric Magnet Pole

Zhou, Yu,Li, Huaishu,Wang, Wei,Cao, Qing,Zhou, Shi The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.3

This paper presented an improved analytical method for calculating the open-circuit magnetic field in the surface-mounted permanent magnet machines accounting for slots and eccentric magnet pole. Magnetic field produced by radial and parallel permanent magnet is equivalent to that produced by surface current according to equivalent surface-current method of permanent magnet. The model is divided into two types of subdomains. The field solution of each subdomain is obtained by applying the interface and boundary conditions. The magnet field produced by equivalent surface current is superposed according to superposition principle of vector potential. The investigation shows harmonic contents of radial flux density can be reduced a lot by changing eccentric distance of eccentric magnet poles compared with conventional surface-mounted permanent-magnet machines with concentric magnet poles. The FE(finite element) results confirm the validity of the analytical results with the proposed model.

Transverse Tensile Deformation and Failure of Three-dimensional Five-directional Braided Carbon Fiber Composites

Wei Zhou,Zhi-yuan Wei,Guang-fei Wang,Kang-ning Han,Ran Liu,Lian-Hua Ma 한국섬유공학회 2021 Fibers and polymers Vol.22 No.4

Accurate characterisation of transverse tensile deformation and damage evolution is of importance for evaluatingthe failure behaviors of three-dimensional (3D) braided composites. In the present study, a finite element method (FEM) andseveral non-destructive testing methods including acoustic emission, digital image correlation, and infrared thermography aredeveloped to investigate the transverse tensile deformation and damage evolution of 3D five-directional braided composites. In the finite element approach, a matrix-impregnated fiber bundles (MIFB) model and a representative volume cell (RVC)model, which take into account the fiber bundles and matrix, are respectively established to predict the effective mechanicalproperties of fiber bundles and simulate the deformation and progressive damage of such composites. The damaged locationsand the failure modes including matrix crack, fiber debonding and shear fracture of fiber are predicted and verified byexperimental tests. The non-destructive tests show that the transverse tensile fracture process can be divided into four stageswhich correspond to acoustic emission signals severally. The combination of the FEM based numerical modeling andmultiple non-destructive characterisation methods can accurately monitor the deformation and damage behaviors of 3Dbraided composites under transverse tensile loads and thus provide a reference for structural health monitoring of compositesin practical application.

Conjugating Automorphisms of Certain Hnn Extensions

Wei Zhou,김관수 영남수학회 2020 East Asian mathematical journal Vol.36 No.3

WeconsiderHNNextensions⟨B,t:t−1Ht=K⟩,whereH,K are in the center of B. We show that conjugating automorphisms of those HNN extensions are inner if B satisfies certain conditions.

Interface engineering for improving reliability of resistance switching in Cu/HfO₂/TiO₂/Pt structure

Wei Zhou, Li,Long Shao, Xing,Yuan Li, Xiang,Jiang, Hao,Chen, Ran,Jean Yoon, Kyung,Jin Kim, Hae,Zhang, Kailiang,Zhao, Jinshi,Seong Hwang, Cheol American Institute of Physics 2015 APPLIED PHYSICS LETTERS Vol.107 No.7

Enhanced Sulfate Reduction by Citrobacter sp. Coated with Fe3O4/SiO2 Magnetic Nanoparticles

Wei Zhou,Maohua Yang,Ziyu Song,Jianmin Xing 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.1

A sulfate-reducing Citrobacter strain was isolatedand coated with Fe3O4/SiO2 magnetic nanoparticles(MNPs) to enhance sulfate reduction. Biolog analysisshowed that it utilizes a broad range of electron donors. The findings also showed that this bacteria strain is afacultative anaerobe and can completely reduce 12 mM ofsulfate to sulfide in 7 days under anaerobic conditions. Moreover, sulfate reduction was enhanced by 79% underoptimized conditions. Different SiO2 wrap-ratios of theMNPs attached to the cell surface were studied to optimizethe sulfate reduction: the surface of cells coated with 300%silica wrap-ratio MNPs showed the highest stability andincreased desulfurization batch time, with a 450% increasein sulfate reduction in comparison with uncoated cellscultivated in anaerobic conditions.