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Correlation between ^(29)Si polymerization and cementitious activity of coal gangue

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第9期10卷 1334-1340页

作者： Ji-xiu ZHANG heng-hu SUN Yin-ming SUN Na ZHANG Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

A new method for estimating the degree of [SiO4]4-polymerization of coal gangue is presented. The method uses the relative bridging oxygen number (RBO) based on nuclear magnetic resonance (NMR) techniques. X-ray diffraction (XRD) and 29Si NMR techniques have been used to study phase transitions and silicate polymerization of coal gangue calcined at different temperatures or co-calcined. It has been found that phase transition of clay minerals causes silicate polymerization to change with temperature. In this study, cementing activity and RBO were determined to be inversely related. Generally, activated coal gangue with lower RBO had better cementitious activity.

关键词： Degree of polymerization Relative bridging oxygen number (RBO) Nuclear magnetic resonance (NMR) Coal gangue Cementitious activity

Corrosion behavior of steel rebar in coal gangue-based mortars

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第5期11卷 382-388页

作者： Ji-xiu ZHANG heng-hu SUN Yin-ming SUN Na ZHANG Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

Corrosion of steel rebar is the most important durability problem of reinforced concrete. The aim of this research was to investigate the corrosion behavior of steel rebar in simulated pore solutions and gangue-blended cement mortar. The simulated pore solutions were based on the pore solution composition of gangue-blended cement. The pH and Cl-concentration of simulated pore solutions had significant effects on corrosion potential. However,an increase in pH reduced the influence of Cl-concentra-tion on corrosion potential. The corrosion behavior of steel rebar in gangue-blended cement is different from that in simulated solutions. The gangue cementitious mortar surrounding steel rebar provides stable passivity environments for steel,leading to a decrease in ion diffusion coefficients. Alternating current impedance (ACI) analysis results indicated that the indicator Rc for concrete resistivity is higher for gangue mortar than for ordinary Portland cement (OPC),which improves its corrosion potential. The results from energy dispersive X-ray analysis (EDX) showed more aluminates and silicates at the rebar interface for gangue-blended cement. These aluminates improve the chloride binding capacity of hydrates in mortar,and increase the corrosion protection of steel rebar.

关键词： Steel rebar Corrosion Coal gangue Electrochemical

Risk-based Optimal Investment and Proportional Reinsurance of an Insurer with Hidden Regime Switching

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Acta Mathematicae Applicatae Sinica 2016年第3期32卷 755-770页

作者： Xing-chun PENG Yi-jun hu School of Science Wuhan University of Technology School of Mathematics and Statistics Wuhan University

In this paper, we study the optimal investment and proportional reinsurance strategy for an insurer in a hidden Markov regime-switching environment. A risk-based approach is considered, where the insurer aims at selecting an optimal strategy with a view to minimizing the risk described by a convex risk measure of its terminal wealth. We solve the problem in two steps. First, we employ the filtering theory to turn the optimization problem with partial observations into one with complete observations. Second, by using BSDEs with jumps, we solve the problem with complete observations.

关键词： investment reinsurance hidden Markov chain convex risk measure backward stochastic differential equation

Research on discharge phenomenon caused by cross‐adsorption of linear insulating fibre and metal dust under DC voltage

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High Voltage 2022年第2期7卷 269-278页

作者： Ruixue Liang Qi hu heng Liu Jian Wang Qingmin Li State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijingChina

A large amount of metal dust is often generated during production and operation of Gas Insulated Switchgear/Gas‐Insulated Transmission Line,and insulating fibres are very easy to mix in during *** discharge phenomenon induced by these two impurities remains *** setting up a test rig with parallel electrodes,the discharge characteristics of metal dust and linear insulating fibres under the negative DC voltage were studied separately and *** obtained research results indicate some interesting phenomena that the metal dust may render‘sand storm’motion characteristics under the action of the electric field,and the linear insulating fibres appear to show‘standing’,‘jumping’,‘flying fire’and other phenomena.A small amount of dust and fibres alone present little effect on the breakdown voltage of the air ***,while the insulating fibres and metal dust coexist,the metal dust will be adsorbed on the surface of the insulating fibres,then the surface charge of the fibres is reallocated,and the discharge phenomenon at both ends of the fibres is enhanced,so that the insulating fibre exhibits similar movement and discharge characteristics to the linear metal *** the same time,the fibres with dust absorbed on will result in an air gap breakdown voltage drop of approximately 25%-40%.What's more,if the discharge of fibres and the‘sand storm’movement of the dust coexist,it may directly lead to‘explosion’of the moving dust,causing severely ablation of the plate surfaces,and thereby the degree of destruction increases dramatically.

关键词： jointly fibre fibres

Targeting 5-HT as a Potential Treatment for Social Deficits in Autism

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Neuroscience Bulletin 2022年第10期38卷 1263-1266页

作者： Guangyi Yang Hongyan Geng chun hu Key Laboratory of Brain Cognition and Education SciencesMinistry of EducationSouth China Normal UniversityGuangzhou510631China Institute for Brain Research and Rehabilitation South China Normal UniversityGuangzhou510631China

One of the most devastating symptoms of autism spectrum disorder(ASD),which affects~0.70%of children in China' Mainland[1],is compromised social skills[2].As it is critical for individuals'survival and adaptive behavioral developments,those diagnosed with ASD may constantly battle the difficulties of mundane social *** noted and assessed by physicians,psychiatrists.

关键词： assessed constantly Mainland

Nonlocal advantage of quantum coherence in a dephasing channel with memory

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Chinese Physics B 2021年第3期30卷 68-73页

作者： Ming-Liang hu Yu-Han Zhang heng Fan School of Science Xi’an University of Posts and TelecommunicationsXi’an 710121China Institute of Physics Chinese Academy of SciencesBeijing 100190China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China

We investigate nonlocal advantage of quantum coherence(NAQC)in a correlated dephasing channel modeled by themultimode bosonic *** obtain analytically the dephasing and memory factors of this channel for the reservoirhaving a Lorentzian spectral density,and analyze how they affect the NAQC defined by the l1 norm and relative *** is shown that the memory effects of this channel on NAQC are state-dependent,and they suppress noticeably the rapiddecay of NAQC for the family of input Bell-like states with one *** the given transmission time of each qubit,we also obtain the regions of the dephasing and memory factors during which there is NAQC in the output states.

关键词： quantum coherence correlated quantum channel memory effects

Relationship between the microstructure and reaction performance of aluminosilicate

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International Journal of Minerals,Metallurgy and Materials 2010年第1期17卷 108-115页

作者： Xiao-ming Liu heng-hu Sun Xiang-peng Feng Na Zhang School of Resource and Safety Engineering China University of Mining ＆ Technology Beijing 100083 China School of Engineering and Computer Science University of the Pacific Stockton CA 95211 USA Shougang Environmental Protection Industry Department Beijing 100041 China Department of Civil and Environmental Engineering University of Wisconsin Madison W153706 USA

A systematic study was conducted to comprehend the mechanism of thermal activation of silica-alumina materials by using ^29Si and ^27Al magnetic angle spinning nuclear magnetic resonance （MAS NMR） spectroscopy. The reaction performance of silica-alumina-based materials with different molar ratios of Si/Al, which were thermally activated, was also investigated. With the increase in calcining temperature, the coordination of Al in metakaolin becomes four, five, and six firstly, and then transforms completely to four and six. It is indicated by identical coupled plasma optical emission spectroscopy （ICP） and NMR that, the reaction performance of monomeric silicate anions is better than that of polymeric silicate anions which are primarily cross-linked in the alkali solution. Moreover, it also shows that the thermal activation temperature, cooling method, and the molar ratio of Na/Ca have remarkable effects on the reaction performance.

关键词： calcination aluminosilicate reaction performance microstructure, nuclear magnetic resonance

One-year survey of opportunistic premise plumbing pathogens and free-living amoebae in the tap-water of one northern city of China

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Journal of Environmental Sciences 2019年第3期31卷 20-31页

作者： Lizhong Liu Xueci Xing chun hu Haibo Wang Key Laboratory of Drinking Water Science and Technology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory for Water Quality and Conservation of the Pearl River Delta Ministry of Education Institute of Environmental Research at Greater Bay Guangzhou University

In this study, qPCR was used to quantify opportunistic premise plumbing pathogens(OPPPs) and free-living amoebae in 11 tap water samples collected over four seasons from a city in northern China. Results demonstrated that the average numbers of gene copies of Legionella spp. and Mycobacterium spp. were significantly higher than those of Aeromonas spp.(p 0.05). Moderate negative correlations between the chlorine concentration and the gene copy numbers of OPPPs were observed by Spearman analysis(rsranged from -0.311 to -0.710, p < 0.05). However, no significant correlations existed between OPPPs and AOC, BDOC, or turbidity. Moderate positive correlations were observed between the target microorganisms, especially for Acanthamoeba spp., through Spearman analysis(p < 0.05). Based on our studies, it is proposed that disinfectant concentration, season, taps with different-use frequency, OPPP species, and potential microbial correlations should be considered for control of OPPPs in tap water.

关键词： Opportunistic premise plumbing pathogens(OPPPs) Free-living amoebae(FLA) Drinking water distribution systems(DWDS) Tap-water Quantitative PCR(qPCR)

Characterization and reactivity of biogenic manganese oxides for ciprofloxacin oxidation

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Journal of Environmental Sciences 2014年第5期26卷 1154-1161页

作者： Jinjun Tu Zhendong Yang chun hu Jiuhui Qu State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesResearch Center for Eco-Environmental Sciences

Biogenic manganese oxides （BioMnOx） were synthesized by the oxidation of Mn（II） with Mn- oxidizing bacteria Pseudomonas sp. G7 under different initial pH values and Mn（II） dosages, and were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and UV-Vis absorption spectroscopy. The crystal structure and Mn oxidation states of BioMnOx depended on the initial pH and Mn（lI） dosages of the medium. The superoxide radical （O2） was observed in Mn-containing （III/IV） BioMnOx suspensions by electron spin resonance measurements. BioMnOx（0.4）-7, with mixed valence of Mn（II/III/IV） and the strongest O^- signals, was prepared in the initial pH 7 and Mn（II） dosage of 0.4 mmol/L condition, and exhibited the highest activity for ciproftoxacin degradation and no Mn（II） release. During the degradation of ciprofloxacin, the oxidation of the Mn（II） formed came from biotic and abiotic reactions in BioMnOx suspensions on the basis of the Mn（II） release and O2- formation from different BioMnOx. The degradation process of ciprofloxacin was shown to involve the cleavage of the hexatomic ring having a secondary amine and carbon-carbon double bond connected to a carboxyl group, producing several compounds containing amine groups as well as small organic acids.

关键词： Mn oxidation state Mn-oxidizing bacteria superoxide radicals ciprofloxacin degradation