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Experimental and numerical investigations of the compressive behavior of carbon fiber-reinforced polymer-strengthened tubular steel T-joints

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Frontiers of Structural and Civil Engineering 2020年第5期14卷 1215-1231页

作者： peng deng Boyi YANG Xiulong CHEN Yan LIU Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation Shandong University of Science and TechnologyQingdao 266590China College of Civil Engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China

A method for strengthening damaged tubular steel T-joints under axial compression by wrapping them with carbon fiber-reinforced polymer(CFRP)sheets was proposed and *** influence of the CFRP strengthening on the failure mode and load capacity of T-joints with different degrees of damage was investigated using experiments and finite element *** T-joints were physically tested:one bare joint to obtain the peak load and corresponding displacement(D1m),two reinforced joints to provide a reference,and two pre-damaged then retrofitted joints to serve as the primary research *** ratio of the pre-loaded specimen chord displacement to the value of D1m was considered to be the degree of damage of the two retrofitted joints,and was set to 0.80 and *** results demonstrate that the maximum capacity of the retrofitted specimen was increased by 0.83%–15.06%over the corresponding unreinforced ***,the capacity of the retrofitted specimen was 2.51%–22.77%lesser compared with that of the directly reinforced ***,111 numerical analysis models(0.63≤b≤0.76,9.70≤g≤16.92)were established to parametrically evaluate the effects of different geometric and strengthening parameters on the load capacity of strengthened tubular T-joints under different degrees of *** numerical analysis results revealed that the development of equivalent plastic strain at the selected measuring points was moderated by strengthening with CFRP wrapping,and indicated the optimal CFRP strengthening thickness and wrapping orientation according to tubular T-joint ***,reasonable equations for calculating the load capacity of CFRP-strengthened joints were proposed and demonstrated to provide accurate *** findings of this study can be used to inform improved CFRP strengthening of damaged tubular steel structures.

关键词： tubular T-joint carbon fiber-reinforced polymer degree of damage numerical analysis equivalent plastic strain

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Combustion behavior and mechanism of molecular perovskite energetic material DAP-4-based composites with metal fuel Al

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Defence Technology（防务技术） 2023年第9期27卷 53-63页

作者： peng deng Xue-yong Guo Hua Fang Rui Liu peng-wan Chen State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081PR China

Combined with the oxidizer anions and fuel cations,molecular perovskite energetic materials show a good *** this work,the combustion behavior and mechanism of metal fuel aluminium(Al)with molecular perovskite energetic material(H_(2)dabco)[NH4(ClO_(4))_(3)](DAP-4)as a high-energy oxidant was *** DAP-4 based composites with metal fuel Al were designed and fabricated by the different mass *** showed that DAP-4 exhibits a good oxygen-supplied capacity for enhancing the combustion performance of *** maximum combustion heat of DAP-4/Al-3 at the Al/O mass ratio of 38:62 is up to 10,412 J/g in the inert gas,which is higher than those of other ratios and the mixtures of other energetic materials and *** evolution of pressure output,pressurization rate,and flame temperature was monitored for DAP-4/Al with different mass *** DAP-4/Al/F were characterized by burning *** combustion reaction mechanism of metal fuel Al with DAP-4 as a high-energy oxidant was ***-4 was ignited firstly and released acid and oxidizing gases,which corroded Al_(2)O_(3)shells on Al particle surfaces and accelerated the combustion reaction with Al to release a lot of *** work offered a new idea that molecular perovskite energetic materials have great potential in the high-energy Al-based solid rocket propellants.

关键词： DAP-4 Metal fuel al Oxidant Combustion behavior Reaction mechanism

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Pigment signatures of some diatoms isolated from China seas

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Acta Oceanologica Sinica 2006年第1期25卷 108-118页

作者： YAO peng YU Zhigang deng Chunmei College of Chemistry and Chemical Engineering Ocean University of China Qingdao 266003 China

The photosynthetic pigments of 12 species （14 strains） of cultured diatoms from six genera under specific conditions were examined by the HPLC. The diatom genera were Skeletonema, Thalassiosira, Chaetoceros, Nitzschla, Phaeodactylum and Meuniera. All strains were isolated from China seas and most of them were from the Jiaozhou Bay, China. Fifteen pigments were identified and eight of them were various chlorophyll a derivatives. Chlorophyll a, c2 and c1 and the carotenoids fucoxanthin, diadinoxanthin, diatoxanthin and β, β-carotene existed in all species. The ratios of each pigment to chlorophyll a were compared with the results in literatures. The pigment ratios of this study generally fall within the ranges reported by the literatures although the maximum ratio of fucoxanthin to chlorophyll a was higher and the ratios of chlorophyll c and diatoxanthin to chlorophyll a were low. The pigment ratios are useful to understanding the pigment signatures of diatoms in the Jiaozhou Bay, China, and to setting up the chemotaxonomic method of phytoplankton in these sea areas.

关键词： diatoms pigment HPLC ratio Jiaozhou Bay

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Current control for a shunt hybrid active power filter using recursive integral PI

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控制理论与应用（英文版） 2009年第1期7卷 77-80页

作者： Wei ZHAO An LUO Ke peng Xia deng College of Electrical and Information Engineering Hunan University Changsha Hunan 410082 China

This paper presents a current control method for a shunt hybrid active power filter （HAPF） using recursive integral PI algorithm. The method improves the performance of the HAPF system by reducing the influence of detection accuracy, time delay of instruction current calculation and phase displacement of output filter. Fuzzy logic based set-point weighing algorithm is combined in the control scheme to enhance its robustness and anti-interference ability. The proposed algorithm is easy to implement for engineering applications and easy to compute. Experiment results have verified the validity of the proposed controller. Furthermore, the proposed recursive integral PI algorithm can also be applied in the control of periodic current as in AC drivers.

关键词： Power electronics Shunt hybrid active power filter Recursive integral PI Fuzzy inference

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Elucidation of the structure, antioxidant, and interfacial properties of flaxseed proteins tailored by microwave treatment

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Journal of Integrative Agriculture 2023年第5期22卷 1574-1589页

作者： YU Xiao DUAN Zi-qiang QIN Xiao-peng ZHU Ying-ying HUANG Feng-hong peng deng-feng BAI Yan-hong deng Qian-chun Oil Crops Research Institute Chinese Academy of Agricultural Sciences/Hubei Key Laboratory of Lipid Chemistry and Nutrition/Key Laboratory of Oilseeds ProcessingMinistry of Agriculture and Rural AffairsWuhan 430062P.R.China College of Food and Bioengineering Zhengzhou University of Light Industry/Henan Key Laboratory of Cold Chain Food Quality and Safety ControlZhengzhou 450002P.R.China

The microwave treatment is commonly applied to flaxseed to release nutrients, inactivate enzymes, remove cyanogens,and intensify flavors. The current study aimed to explore the influences of microwave exposure on the antioxidant and interfacial properties of flaxseed protein isolates(FPI), focusing on the altering composition and molecular *** results showed that after microwave exposure(700 W, 1–5 min), more compact assembly of storage proteins and subsequent permeation by membrane fragments of oil bodies occurred for cold-pressing flaxseed flours. Moreover, the particle sizes of FPI was progressively reduced with the decrement ranged from 37.84 to 60.66%(P<0.05), whereas the zeta potential values initially decreased and then substantially recovered during 1–5 min of microwave exposure. The conformation unfolding, chain cross-linking, and depolymerization were sequentially induced for FPI based on the analysis of fluorescence emission spectra, secondary structure, and protein subunit profiles, thereby affecting the dispersion or aggregation properties between albumin and globulin fractions in FPI. Microwave exposure retained specific phenolic acids and superior in vitro antioxidant activities of FPI. The inferior gas–water interface absorption and the loose/porous assembly structure were observed for the foams prepared by FPI, concurrent with obviously shrinking foaming properties upon microwave exposure. Improving oil–water interface activities of FPI produced the emulsion droplets with descending sizes and dense interface coating, which were then mildly destabilized due to the lipid leakage and weakened rheological behavior with microwave exposure extended to 5 min. Our findings elucidated that microwave treatment could tailor the application functionality of protein fractions in flaxseed based on their in situ structural remodeling.

关键词： microwave exposure flaxseed protein isolates antioxidant activities interfacial properties composition structure

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Soliton Solutions for Nonisospectral AKNS Equation by Hirota＇s Method

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Communications in Theoretical Physics 2006年第3期45卷 398-400页

作者： BI Jin-Bo SUN Ye-peng CHEN deng-Yuan Department of Mathematics Shanghai University Shanghai 200444 China

Bilinear form of the nonisospectral AKNS equation is given. The N-soliton solutions are obtained through Hirota＇s method.

关键词： nonisospectral AKNS equation soliton solutions Hirota's method

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Histone methyltransferases and demethylases:regulators in balancing osteogenic and adipogenic differentiation of mesenchymal stem cells

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International Journal of Oral Science 2015年第4期7卷 197-204页

作者： peng deng Qian-Ming Chen Christine Hong Cun-Yu Wang Division of Oral Biology and Medicine School of DentistryUniversity of California at Los Angeles State Key Laboratory of Oral Disease West China School of StomatologySichuan University Section of Orthodontics School of DentistryUniversity of California at Los Angeles Department of Bioengineering Henry Samueli School of Engineering and Applied ScienceUniversity of California at Los Angeles

Mesenchymal stem cells （MSCs） are characterized by their self-renewing capacity and differentiation potential into multiple tissues. Thus, management of the differentiation capacities of MSCs is important for MSC-based regenerative medicine, such as craniofacial bone regeneration, and in new treatments for metabolic bone diseases, such as osteoporosis. In recent years, histone modification has been a growing topic in the field of MSC lineage specification, in which the Su（var）3-9, enhancer-of-zeste, trithorax （SET） domain-containing family and the Jumonji C （JmjC） domain-containing family represent the major histone lysine methyltransferases （KMTs） and histone lysine demethylases （KDMs）, respectively. In this review, we summarize the current understanding of the epigenetic mechanisms by which SET domain-containine KMTs and JmiC domain-containinlz KDMs balance the osteogenic and adipogenic differentiation of MSCs.

关键词： adipogenesis histone methylation histone lysine methyltransferase histone lysine demethylase mesenchymal stemcells osteogenesis

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Thermal decomposition effect of MgCo_(2)O_(4)nanosheets on ammonium perchlorate-based energetic molecular perovskites

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Defence Technology（防务技术） 2023年第2期20卷 111-119页

作者： Er-hai An Xiao-xia Li Hai-xia Zhao Ying-xin Tan Xiong Cao peng deng School of Environment and Safety Engineering North University of ChinaTaiyuan030051ShanxiPeople's Republic of China School of Engineering for Safety and Emergency Management Taiyuan University of Science and TechnologyTaiyuan030024China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081People's Republic of China

Energetic molecular perovskites have attracted widespread attention in the fields of energy materials due to their high detonation *** this work,we reported the effect of MgCo_(2)O_(4) nanosheets on the thermal decomposition of ammonium perchlorate(NH_(4)ClO_(4),AP)-based energetic molecular perovskites(AP-based energetic molecular perovskites).The morphology and structure of the MgCo_(2)O_(4) nanosheets were *** their catalytic effect on the thermal decomposition of AP-based energetic molecular perovskites(H_2pz)[NH_(4)(ClO_(4))_(3)](PAP-4),(H_2dabco)[NH_(4)(ClO_(4))_(3)](DAP-4),(H_2mpz)[NH_(4)(ClO_(4))_(3)](PAP-M_(4)),and (H_2hpz)[NH_(4)(ClO_(4))_(3)](PAP-H_(4)) was *** results showed that MgCo_(2)O_(4) nanosheets had excellent intrinsically catalytic performance towards enhancing the thermal decomposition of AP-based energetic molecular *** adding MgCo_(2)O_(4) nanosheets,the thermal decomposition peak temperatures of PAP-4,DAP-4,PAP-M_(4),and PAP-H_(4) had been reduced by35.7℃,48.4℃,37.9℃,and 43.6℃,*** the activation energy(Ea)of the thermal decomposition of AP-based energetic molecular perovskites had been reduced,the Eaof PAP-H_(4) decreased by 46.4 kJ/mol at most among *** catalytic mechanism of MgCo_(2)O_(4) nanosheets for AP-based energetic molecular perovskites is *** work provides a reference for the future application of AP-based energetic molecular perovskites.

关键词： AP-based energetic molecular perovskites MgCo_(2)O_(4)nanosheets Thermal decomposition Catalytic performance

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The Modification on the Discreteness of Park-Ang Damage Index Based on Bayesian Methodology

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Journal of Harbin Institute of Technology(New Series) 2014年第1期21卷 102-108页

作者： Yi-Bin He peng deng Chao Zhang Pu-Sheng Shen College of Civil Engineering Hunan University

The discreteness is a common deficiency which impedes damage indices' practical application. It is caused by the arbitrary linear combination and some missing necessary variables. In order to deal with this problem,the correction term was added to the widely cited Park-Ang damage index. The unknown parameters in the correction term were obtained by the maximum likelihood estimation of these parameters' posterior distributions updated through Bayesian methodology. And the specimens for Bayesian updating were selected from PEER column database and Kawashima Earthquake Engineering Laboratory. Through model simplification process,a simplified modification was adopted,which has improved its goodness of fit to the experimental data. It has been found that the concrete core area and cross sectional area ratio,the longitudinal reinforcement ratio and the damage concentration factor are the critical variables affecting the error of the original damage index.

关键词： bayesian methodology damage index reinforced concrete seismic behavior

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Abrasive Wear Behavior and Mechanism of High Chromium Cast Iron

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Journal of Iron and Steel Research International 2015年第1期22卷 84-90页

作者： Ting SUN Ren-bo SONG Xu WANG peng deng Chun-jing WU School of Materials Science and Engineering University of Science and Technology Beijing

The abrasive wear behavior of high chromium cast iron （containing 12.9 mass% chromium） austenitized at 1 050 ℃ for 2 h and austempered in salt bath at 320 ℃ for 4 h was evaluated. Abrasive wear was performed using alumina abrasive under four different loads, namely 50, 100, 150, and 200 N, for 36000 cycles. The worn surfaces and wear debris were analyzed by scanning electron microscopy, laser confocal microscopy and X-ray diffraction. Micro hard- ness profiles were also obtained in order to analyze the strain-hardening effects beneath the contact surfaces. Results indicate that the retained austenite in high chromium cast iron has experienced induced martensitic transformation af- ter tests, for small amounts of retained austenite could be detected by X-ray diffraction. In addition, there is a close relationship between wear mechanism and test load. Under the condition of lower test load, the wear mechanism is an uninterrupted and repeated process, during which matrix is cut at first and then fine carbides flake off. As to high- er test load, scratching and spalling induced by cleavage fracture of blocky carbide are the wear mechanism.

关键词： high chromium cast iron abrasive wear wear mechanism wear behavior martensitic transformation

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