Structural Performance of Earthquake-damaged Beams in Fire

Bo Wen,Lu Zhang,Bo Wu,Ditao Niu 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.12

Post-Earthquake Fire (PEF) on frame structures usually leads to complicated and unpredictable thermal performance of damaged concrete members. In order to determine the structural performance of seismic-damaged Reinforced Concrete (RC) beams under PEF conditions, the RC frame structures are subjected to the shake table test. The test, used in conjunction with other existing seismic hazard data, demonstrates that the main geometric damage forms of RC beams after the earthquake are cracks and concrete spalling. Subsequently, calculating models of PEF RC beams are established in ABAQUS, and then the distribution of thermal field, hightemperature bearing capacity and reduction coefficient of seismic-damaged beams are proposed respectively. From experimental and numerical investigations, It can conclude that (a) the simplified numerical models are proven to accurately determine the fire performance of the damaged RC beams; (b) the thermal performance degradation caused by spalling is more severe than the degradation caused by cracking on PEF RC beams, which demonstrates that spalling takes a more important role than cracking; and (c) the prediction equation of the flexural bearing capacity reduction factor of PEF RC beams is feasible.

윌리엄 보웬(William M. Bowen) : 학제적 지역연구의 지평을 열다

윌리엄 보웬(William M. Bowen),권성문(Sung Moon Kwon) 국토연구원 2016 국토 : planning and policy Vol.421 No.-

Modeling and Virtual Screening of Antisense Peptides Targeting the Divergent Region of Tumor-Associated MT1-MMP Protein

Bowen Tan,Yijie Zhou,Zhilei Song,Yinxuan Peng,Fang Wu,Yue Kang,Xiaomin Liu,Li Zeng,Tingting Huang,Zongying Liu,Lili Xiong,Zhiyun Guo,Jian Cui,Canquan Mao 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.9

Membrane type-1 matrix metalloproteinase (MT1-MMP; also known as MMP14) is a key enzyme involved in tumor invasion and metastasis, and is a potential target for drug discovery for cancer therapy. However, till now there is no MT1-MMP- or MMP-based anticancer drugs in the market mainly because of the high conservation of the MMP family and also because there is no elucidated crystal structure for the mature MT1-MMP. The modeling of the three-dimensional structure of mature MT1-MMP and the finding of MT1-MMP targeted peptides by virtual screening are highly desired. In this study, the three-dimensional structure of mature MT1-MMP is constructed by homology and de novo modeling and later rationalized and optimized by molecular dynamics simulations. An antisense peptide library was constructed against the divergent sense peptide DEGTEEET in the specific region of MT1-MMP, which was found by multiple alignment of the whole MMP family. The antisense peptide library was virtually screened against the constructed three-dimensional model of MT1-MMP. The top 20 novel peptides were further studied, which were found well docked with MT1-MMP at the region of DEGTEEET, again confirming their specific binding to MT1-MMP. Preliminary study of one of the top-ranked peptide SFLLSPFV showed that it could inhibit the viabilities of MG63 and MDA-MB-231 tumor cells. We thus not only successfully modeled the three-dimensional structure of mature MT1-MMP but also provided a new way for the finding of peptide candidates targeting MT1-MMP based on antisense peptide library.

Digital twin in grinding machine: Prediction of grinding force with PLC program

Bowen Qi,Hong-Seok Park(박홍석),Chang-Myung Lee 한국자동차공학회 2020 한국자동차공학회 부문종합 학술대회 Vol.2020 No.7

Metallogenesis and hydrothermal evolution of the Saibo copper deposit in the western Tianshan: evidence from fluid inclusions, H-O-S isotopes, and Re-Os geochronology

Bowen Zhang,Xiaofei Tang,Chuan Chen,Xiaoping Gong,Chunmei Su 한국지질과학협의회 2023 Geosciences Journal Vol.27 No.1

The Saibo copper polymetallic deposit, located in the West Tianshan Sailimu-Sitaihaiquan copper lead and zinc ore belt, is a new breakthrough in medium-large copper mine. Through the thin section authentication and the thermometric analysis of fluid inclusion, it is concluded that skarnization was developed in this deposit, the mineralization stage can be divided into retrograde skarn stage (S1), quartz-sulfide stage (S2) and quartz-carbonate stage (S3). Fluid inclusions (FIs) were distinguished as liquid-rich aqueous FIs (LV-type), vapor-rich aqueous FIs (VL-type), and NaCl daughter mineral-bearing three phase FIs (S-type). The mineralization fluids indicate that the initial stage (S1 stage) is of high temperature and high salinity, with a handful of metallicmatters. During the main metallogenic stage (S2 stage), the meteoric water is mixed, the temperature and salinity gradually decrease, the fluid is distinctly boiling, and a large amount of metallic matters are precipitated, and then to the S3 stage, when the temperature and salinity decrease along with the carbonation. Chalcopyrite Re-Os dating yielded a mineralization age of 379.2 ± 7.7 Ma, which corresponds well with the zircon U-Pb age (385.9 ± 1.3 Ma) of the granite porphyry. The C-H-O isotopes indicate that the ore-forming fluid was dominated by initial mixed magmatic water in the early stage and by meteoric water in the late stage, and C is derived from limestone strata metasomatized by magmatic fluids. The S and Pb isotopes indicate that the ore-forming materials are derived from the mixed crust-mantle source, of which S is almost entirely derived from the mantle, while Pb is mainly derived from the crustal material of the orogenic belt. On the whole, the Saibo copper deposit is a typical calcium skarn type deposit, which formed in the shallower setting at active continental margin in the Late Devonian period.

Enforcement of opacity security properties for ship information system

Bowen Xing,Jin Dai,Sheng Liu 대한조선학회 2016 International Journal of Naval Architecture and Oc Vol.8 No.5

In this paper, we consider the cybersecurity issue of ship information system (SIS) from a new perspective which is called opacity. For a SIS, its confidential information (named as “secret”) may be leaked through the working behaviors of each Distributed Control Unit (DCU) from an outside observer called an “intruder” which is able to determine ship's mission state by detecting the source of each data flow from the corresponding DCUs in SIS. Therefore we proposed a dual layer mechanism to enforce opacity by activating non-essential DCU during secret mission. This mechanism is calculated by two types of insertion functions: Safety-assured insertion function ( fIS) and Admissibility-assured insertion function ( fIA). Due to different objectives, fIS is designed to confuse intruder by constructing a non-secret behaviors from a unsafe one, and the division of fIA is to polish the modified output behaviors back to normal. We define the property of “I2eEnforceability” that dual layer insertion functions has the ability to enforce opacity. By a given mission map of SIS and the marked secret missions, we propose an algorithm to select fIS and compute its matchable fIA and then the DCUs which should be activated to release non-essential data flow in each step is calculable.

Microcapsules derived from Pickering emulsions as thermal latent curing accelerator for epoxy resins

Bowen Zhang,Yingying Zhao,Xin Sun,Xiaoma Fei,Weiwei Wang,Xiaojie Li,Xiaoya Liu 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.83 No.-

Organic-inorganic hybrid microcapsules encapsulating 2-phenylimidazole (2-PhIm) were prepared byPickering emulsion polymerization of styrene and divinyl benzene using methacryloyloxy silanemodifiedsilica particles as the stabilizer, and served as a thermal latent curing accelerator fordiglycidylether of bisphenol A epoxy/anhydride system. The one-component curing compositioncontaining 5 wt% of the microcapsules exhibited an excellent storage stability. The pot life at roomtemperature was as long as 30 days, while which of 2-PhIm curing system was only 2 days. At elevatedtemperature, the encapsulated 2-PhIm could be released from microcapsules effectively, and instantlyaccelerated the curing reaction. Meanwhile, the addition of microcapsules did not cause an adverse effecton the thermomechanical performance of the epoxy thermosets. In addition, the latency and curingbehavior could be facilely regulated at a wide range of temperature by adjusting monomer ratios of thepolymer matrix, to match different process temperatures. The microcapsules with robust cross-linkedpolystyrene matrix structure also showed good resistance to shearing forces, indicating their feasibilityfor high-speed mixing or kneading process in practical applications. It is suggested that the novel latentcuring accelerator is potential for high-performance one-pot epoxy formulations, particularlyrecommended for application in electronic packagingfields.

Circuit Model for the Effect of Nonradiative Recombination in a High-Speed Distributed-Feedback Laser

Bowen Nie,Zhijuan Chi,Qing-an Ding,Xiang Li,Changqing Liu,Xiaojuan Wang,Lijun Zhang,Juan Song,Chaofan Li 한국광학회 2020 Current Optics and Photonics Vol.4 No.5

Based on single-mode rate equations, we present an improved equivalent-circuit model for distributedfeedback (DFB) lasers that accounts for the effects of parasitic parameters and nonradiative recombination. This equivalent-circuit model is composed of a parasitic circuit, an electrical circuit, an optical circuit, and a phase circuit, modeling the circuit equations transformed from the rate equations. The validity of the proposed circuit model is verified by comparing simulation results to measured results in the literature. The results show that the slope efficiency and threshold current of the model are 0.22 W/A and 13 mA respectively. It is also shown that increasing bias current results in the increase of the relaxation-oscillation frequency. Moreover, we show that the larger the bias current, the lower the frequency chirp, increasing the possibility of extending the transmission distance of an optical-fiber communication system. The results indicate that the proposed circuit model can accurately predict a DFB laser’s static and dynamic characteristics.

In-Situ Observation of Grain Refinement in the Simulated Heat-Affected Zone of High-Strength Low-Alloy Steel by Zr-Ti Combined Deoxidation

Bowen Zhou,Guangqiang Li,Xiangliang Wan,Yu Li,Kaiming Wu 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.2

The effect of Zr-Ti combined deoxidation on the grain refinement in the simulated coarse-grained heat-affected zone of a high-strength low-alloy steel was investigated by means of analytical characterization techniques such as in-situ microscopy, transmission electron microscopy, and electron backscattered diffraction analysis. Owing to the Zr-Ti combined deoxidation, a large amount of fine Zr-Ti oxide particles were formed in the steel and retarded the austenite grain growth during simulated welding thermal cycle. The austenite grains were small and uniform. The Mn can diffuse spontaneously from austenite to Zr-Ti oxide inclusion and MnS precipitated on ZrO2, which can form Mn depleted zone in the vicinity of inclusion. The acicular ferrite grains nucleated on intragranular Zr-Ti oxide inclusions in austenite grains grew in different directions and effectively divided the austenite grain into several finer and separate regions at intermediate temperature. The crystallographic grain size became small in the simulated coarse-grained heat-affected zone of Zr-Ti-killed steel due to the effective pinning effect by Zr-Ti oxide particles and acicular ferrite formation.

Dynamic analysis of the dual-rotor system considering the defect size uncertainty of the inter-shaft bearin

Bowen Tian,Zeyang Yu,Liyang Xie,Yu Zhang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.2

In this paper, the stochastic dynamic analysis of a dual-rotor system with a local defect on the inner raceway of the inter-shaft bearing is presented. The dynamic model of the dual-rotor system is also proposed. The defect size and its uncertainty are considered. The non-intrusive polynomial chaos expansion model is utilized to deal with the uncertainty of the defect size, and the validity of the model is verified. The probability density distribution of vibration displacements for the dual-rotor system is obtained. Results indicate that the mean value (MV) and standard deviation (SD) of the defect edge length have extremely significant effects on the displacement distribution of high-pressure rotor. The coefficients of variation of the displacements along x 2 and φ x directions for high-pressure rotor increase by 6.56 and 7.06 times, respectively. When the MV of the defect edge length increases by three times, 3.46 times, and 3.69 times, its SD increases by five times. The increase of eccentricity has opposite effects on the vibration displacements of high- and low-pressure rotors. The variation of the radial clearance of the inter-shaft bearing has a complex influence on the dual-rotor system. As the radial clearance increases, the displacement dispersion of the low-pressure rotor along θ x direction is almost unchanged. However, that along x 1 direction is increased.