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.

Dynamic simulation and control of a triple column process for dimethyl carbonate- methanol separation

Hong-Mei Wei,Qiang Gao,Wei-zhou Jiao,Wei Wei 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.12

Separation of dimethyl carbonate/methanol azeotropic mixture by using pressure-swing distillation processhas been a hot-point in the study of the synthesis process of dimethyl carbonate by urea methanolysis method. Thisstudy updates the work of the writers (Ind.Eng.Chem.Res,2013,52,11463-11478), which explores the dynamic controlstructure of the three-column separation dimethyl carbonate (DMC)/methanol (MeOH) process from an actual pilotplant. At first, the conventional DMC/MeOH separation process in the pilot test of the DMC synthesis process throughalcoholysis of urea was described in detail. Then an optimized control structure for the entire DMC/MeOH separationunit was obtained by implementing a general heuristic design procedure. An economic analysis was performed to evaluatethe optimized process. Finally, three dynamic control schemes were proposed and evaluated with several large disturbances,an improved control scheme CS3, using the multiplier blocks “QR1/F1” and “RR1” in T1, “QR1/F1” and “R/F”in both T2 and T3, outperformed CS1 and CS2 by maintaining the product specification in each column.

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.

Broadband and ultra-low reflection metamaterial absorber embedded with magnetic materials

Zhou Wei,Zhu Zhenghou,Zou Qiang,Yuan Zhifen,Liu Rongyu 한국물리학회 2022 Current Applied Physics Vol.41 No.-

In this study, we design, prepare and characterize a broadband, ultra-low reflectivity and incidence angle-insensitive metamaterial absorber. The design of this absorber not only provides a novel idea for the design of broadband absorbers, but also enhances the application prospects of metamaterial absorbers. By introducing FeSiAlp/epoxy magnetic composite and optimizing the structural parameters, the absorption performance of the metamaterial absorber has been significantly improved. The effective absorption bandwidth (bandwidth with reflectivity less than -10dB) is increased by 3.4 times from 2.19 GHz to 7.49 GHz, and the RLmin (minimum reflection loss) value reaches -38.31 dB at 17.83 GHz, that is the absorption rate reaches 99.99%. Meanwhile, the experimental results also verify the simulation design results. Therefore, the absorber not only plays the characteristics of strong absorption of metamaterial, but also absorbs the advantages of broadband of magnetic material.

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.

Language Attitude of Ethnic Chinese in Four Southeast Asian Countries

Wei Zhou,Jun-Eon Park 한국외국어교육학회 2017 Foreign languages education Vol.24 No.3

Today, tens of millions of ethnic Chinese are scattered throughout Southeast Asia as a result of the massive influx of immigrants from China during the past several centuries. The present study analyzed the language attitude of the ethnic Chinese in Southeast Asia, focusing on four countries: Indonesia, Thailand, Malaysia, and Singapore. For this purpose, a total of 177 samples of language attitude questionnaire were collated. The questionnaire was composed of 11 language attitude-related elements in affective, behavioral, and cognitive components with respect to the multiple languages used in the countries: national language, English, local Chinese dialects, Mandarin, and others. Analysis of the data reveals intriguing findings about the language attitude of the ethnic Chinese in different countries. Both the similarities and the differences of language attitude are found among the ethnic Chinese groups in the Southeast Asian countries, reflecting the political, economic, and social situations of each country. The prospect of the local Chinese dialects look dim due to exogenous factors surrounding the linguistic ecosystems in the region.

An Interference Isolation Method for Wireless Power and Signal Parallel Transmissions on CPT Systems

Zhou, Wei,Su, Yu-Gang,Xie, Shi-Yun,Chen, Long,Dai, Xin,Zhao, Yu-Ming The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.1

A novel interference isolation method is proposed by using several designed coils in capacitive power transfer systems as isolation impedances. For each designed coil, its stray parameters such as the inter-turn capacitance, coil resistance and capacitance between the coil and the core, etc. are taken into account. An equivalent circuit model of the designed coil is established. According to this equivalent circuit, the impedance characteristic of the coil is calculated. In addition, the maximum impedance point and the corresponding excitation frequency of the coil are obtained. Based on this analysis, six designed coils are adopted to isolate the interference from power delivery. The proposed method is verified through experiments with a power carrier frequency of 1MHz and a data carrier frequency of 8.7MHz. The power and data are transferred parrallelly with a data carrier attenuation lower than -5dB and a power attenuation on the sensing resistor higher than -45dB.

An Interference Isolation Method for Wireless Power and Signal Parallel Transmissions on CPT Systems

Wei Zhou,Yu-Gang Su,Shi-Yun Xie,Long Chen,Xin Dai,Yu-Ming Zhao 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.1

A novel interference isolation method is proposed by using several designed coils in capacitive power transfer systems as isolation impedances. For each designed coil, its stray parameters such as the inter-turn capacitance, coil resistance and capacitance between the coil and the core, etc. are taken into account. An equivalent circuit model of the designed coil is established. According to this equivalent circuit, the impedance characteristic of the coil is calculated. In addition, the maximum impedance point and the corresponding excitation frequency of the coil are obtained. Based on this analysis, six designed coils are adopted to isolate the interference from power delivery. The proposed method is verified through experiments with a power carrier frequency of 1MHz and a data carrier frequency of 8.7MHz. The power and data are transferred parrallelly with a data carrier attenuation lower than -5dB and a power attenuation on the sensing resistor higher than -45dB.

CONJUGATING AUTOMORPHISMS OF CERTAIN HNN EXTENSIONS

Zhou, Wei,Kim, Goansu The Youngnam Mathematical Society 2020 East Asian mathematical journal Vol.36 No.3

We consider HNN extensions 〈B, t : t^―1Ht = K〉, where H, K are in the center of B. We show that conjugating automorphisms of those HNN extensions are inner if B satisfies certain conditions.

Whether can Posner-Schlossman syndrome be treated through a physiotherapy, ciliary muscle training method?

Wei Zhou,Xiaoyan Zhang 셀메드 세포교정의약학회 2015 셀메드 (CellMed) Vol.5 No.4

A new physiotherapy named Ciliary Muscle Training method and one successful case had been reported first for treatment of Posner-Schlossman Syndrome (PSS), also known as Glaucomatocyclitic Crisis. When a person observed a back and forth moving object, the ciliary muscle would involuntarily do sometimes tense and sometimes relaxant exercise which can relieve the tensive state of the ciliary muscle of patients suffering PSS disease. Through this period of continued treatment, this ciliary muscle training method can improve the health status of the ciliary muscle and finally achieve the purpose of curing PSS disease. In this successful case, the patient’s feedback result was very good after receiving our suggested ciliary muscle training method as an attempt to treat PSS, ill right eye of this PSS patient showed normal appearance without any differences from the other normal eye, his vision test values of naked eye were both 4.9 under nearly 200 degrees of myopia. High intraocular pressure (IOP) was mitigated, measured IOP value was in the normal (≦ 21 mmHg) and comfortable state without PSS relapse until now. Therefore, ciliary muscle training method could be a potential clinical treatment approach to PSS disease.