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Chemical mapping of cement pastes by using confocal Raman spectroscopy

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Frontiers of Structural and Civil Engineering 2016年第2期10卷 168-173页

作者： Fengjuan LIU zhihui sun Department of Civil Construction and Environmental Engineering The University of Alabama Tuscaloosa AL 35487 United States Department of Civil and Environmental Engineering University of Louisville Louisville KY 40292 United States

In the present study, chemical mapping on the hydration process of cement paste with water-to-cement （w/c） ratio of 0.60 was implemented by Raman spectroscopy （RS）. The RS was applied to study the paste from 12 hours after mixing to 28 days. Cement ingredients and hydration products, including calcium silicates （C3S and C2S）, calcium hydroxide （CH）, and ettringite, were quantitatively studied. From the research, it is observed that calcium silicates were consumed gradually with the increased hydration age. Calcium hydroxide increased and tended to cluster in the pore vicinity during hydration. Ettringite was found to form on the surface of the unreacted particles, which was shown as a mixed zone of ettringite and calcium silicates in the maps. It is concluded from the study that chemical mapping was an effective method to assist in visualizing particle dispersion and connection on top of the quantitative analysis.

关键词： chemical mapping Raman spectroscopy calcium silicates calcium hydroxide ettringite

Current application and future directions of photobiomodulation in central nervous diseases

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Neural Regeneration Research 2021年第6期16卷 1177-1185页

作者： Muyue Yang Zhen Yang Pu Wang zhihui sun Shanghai Jiao Tong University ShanghaiChina Core Facility of West China Hospital ChengduSichuan ProvinceChina Department of Rehabilitation Medicine the Seventh Affiliated Hospital of Sun Yat-sen UniversityShenzhenGuangdong ProvinceChina Department of Psychosomatic Medicine The People’s Hospital of Suzhou New DistrictSuzhouJiangsu ProvinceChina

Photobiomodulation using light in the red or near-infrared region is an innovative treatment strategy for a wide range of neurological and psychological *** can promote neurogenesis and elicit anti-apoptotic,antiinflammatory and antioxidative *** therapeutic effects have been demonstrated in studies on neurological diseases,peripheral nerve injuries,pain relief and wound *** conducted a comprehensive literature review of the application of photobiomodulation in patients with central nervous system diseases in February *** NCBI PubMed database,EMBASE database,Cochrane Library and ScienceDirect database were *** reviewed 95 papers and *** has wide applicability in the treatment of stroke,traumatic brain injury,Parkinson’s disease,Alzheimer’s disease,major depressive disorder,and other *** analysis provides preliminary evidence that PBM is an effective therapeutic tool for the treatment of central nervous system ***,additional studies with adequate sample size are needed to optimize treatment parameters.

关键词： Alzheimer’s disease central nervous system diseases major depressive disorder Parkinson’s disease photobiomodulation stroke traumatic brain injury

Constructal optimization on T-shaped cavity based on entransy dissipation minimization

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Chinese Science Bulletin 2009年第23期54卷 4418-4427页

作者： XIE zhihui CHEN LinGen sun FengRui Postgraduate School Naval University of Engineering Wuhan 430033 China

The entransy dissipation extremum principle provides new warranty and criterion for optimization of heat transfer. For a heat transfer model of a rectangular solid wall with an open T-shaped cavity, a dimensionless equivalent thermal resistance based on entransy dissipation is taken as optimization objective, and constructal optimization for the model is carried out when the system volume, the cavity volume and the volume of rectangle occupied by T-shaped cavity are fixed. Numerical results indicate that the optimal geometry construct of cavity can be schemed out based on entransy dissipation extremum principle. The formulation of dimensionless global (maximum) thermal resistance presented in a literature is modified; some new rules which are different from those reported in the literature are obtained based on the minimization of the modified objective. Comparisons of the numerical results show that the optimal system constructs deduced respectively from the two thermal resistance objectives are very different. The optimization by taking equivalent thermal resistance minimization as objective can more effectively reduce mean temperature difference of heat transfer than the optimization by taking maximum thermal resistance minimization as objective, so that the performance of heat transfer for the total system can be improved. The more freedom the cavity has, the better the total system performance is. The correlations of the equivalent thermal resistance and the maximum thermal resistance of the system and three geometric degrees of freedom are found by using function fitting.

关键词：最小化损耗 T形优化构形

An estimation model of time-varying origin-destination flows in expressway corridors based on unscented Kalman filter

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Science China(Technological Sciences) 2009年第7期52卷 2069-2078页

作者： LI JunWei LIN BoLiang sun zhihui GENG XueFei State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong UniversityBeijing 100044China School of Light Industry Harbin University of CommerceHarbin 150076China

On the basis of measurable time series of mainline and ramp flows from traffic counts and the assumption of travel time distributions, this research presents a dynamic system model and its on-line estimation algorithm for recursive estimation of time-varying origin-destination (OD) matrices in expressway corridors. The proposed model employs a macro-traffic flow model to estimate travel times of OD flows and uses parameters of the traffic model as state variables, which are added to the constrained function of the system. To improve the model efficiency, we revise the travel time distribution based on the feature of normal distribution. The research employs a newly developed filtering technique, called unscented Kalman filter. The proposed model is evaluated with simulation experiments. Numerical analyses with respect to the sensitivity of the selection of initial parameters on the estimation results indicate that the proposed model is sufficiently reasonable and stable for real-world appli-cations.

关键词： OD estimation expressway Kalman filtering algorithm

Properties of Aluminum Oxide (AlO_x) Barrier Coatings Deposited on Poly(Ethylene Terephthalate)(PET)Substrates by Reactive Magnetron Sputtering

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稀有金属材料与工程 2012年第S1期41卷 268-271页

作者： Liu Zhuang Ma Xinxin sun zhihui Xu Fangjun Harbin Inst Technol Sch Mat Sci & Engn Harbin 150001 Peoples R China Harbin Univ Commerce Harbin 150028 Peoples R China

The aluminum oxide(AlOx)coatings were deposited on poly(ethylene terephthalate)(PET)surface by reactive magnetron sputtering for improving its barrier *** O2 flux increasing,three modes including metallic mode,transition mode and oxide mode exist in *** properties of the aluminum oxide(AlOx)coatings prepared at different modes were ***,the influences of oxygen flux on the stoichiometry,structure,gas permeation of the coatings were *** chemical composition of AlOx films fabricated in transition mode is different as oxygen flux varies slightly,and the gas barrier property is better as the stoichiometry is closer to 1.5 with oxygen flux *** coating uniformity,roughness and particle size depend remarkably upon oxygen *** coatings deposited at oxide mode have a good barrier performance to oxygen and water,and the permeability to oxygen decreases by sixty times and water vapor ten times compared with uncoated

关键词： permeation barrier aluminum oxide magnetron sputtering poly(ethylene terephthalate)(PET)

Sputter Deposited Carbon Material based Fabry-Perot Sensor and Downhole Application

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Journal of Wuhan University of Technology(Materials Science) 2022年第6期37卷 1143-1149页

作者： WANG Yingying LIU Xiaohui CHEN Xiaoan sun zhihui ZHAO Qingchao Laser Institute Qilu University of Technology(Shandong Academy of Sciences)Jinan 250103China School of Geophysics and Information Technology China University of Geosciences(Beijing)Beijing 100191China Logging Technology Research Institute China National Logging CorporationXi’an 710077China Shandong Computer Science Center Qilu University of Technology(Shandong Academy of Sciences)Jinan 250014China

To prevent hydrogen-induced loss and achieve long-term effective parameters monitoring in harsh downhole environment,we proposed a Fabry-Perot sensor with vacuum sputter deposited carbon coating film,in which we employed a deposition technology with a higher particle kinetic energy,closer substrate adhesion,and denser films,to deposit the coating film on the surface of the quartz capillary glass tube to protect the sensor from *** sensitivity and accuracy of the Fabry-Perot sensor with carbon film deposition can reach 369 nm/MPa and 0.02%FS,***,the sensor has less hysteresis error and good pressure linearity of more than 0.99999 for repeatable pressure *** downhole practice monitoring data indicated that this fiber-optic sensor exhibited excellent performance and the sputter deposited carbon coating can effectively decrease hydrogen loss.

关键词： quartz substrate Fabry-Perot sensor vacuum sputtering carbon coating material

A Trusted Attestation Mechanism for the Sensing Nodes of Internet of Things Based on Dynamic Trusted Measurement

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China Communications 2018年第2期15卷 100-121页

作者： Bei Gong Yubo Wang Xiangang Liu Fazhi Qi zhihui sun Faculty of Information Technology Beijing University of Technology Beijing 100124 China China Electronics Standardization Institute Beijing 100007 China Institute of High Energy Physics Chinese Academy of Sciences

Internet of things has been widely applied to industrial control, smart city and environmental protection, in these applica- tion scenarios, sensing node needs to make real-time response to the feedback control of the application layer. Therefore, it is nec- essary to monitor whether or not awareness nodes are trusted in real time, but the existing mechanisms for trusted certification lack the real-time measurement and tracking of the sensing node. To solve the above problems, this paper proposes a dynamic metric based authentication mechanism for sensing nodes of Internet of things. Firstly, the dynamic trustworthiness measure of the sensing nodes is carried out by introducing the computational function such as the trust function, the trust- worthiness risk assessment function, the feed- back control function and the active function of the sensing node. The dynamic trustworthi- ness measure of sensing nodes from multiple dimensions can effectively describe the change of trusted value of sensing nodes. Then, on the basis of this, a trusted attestation based on node trusted measure is realized by using the revocable group signature mechanism of local verifier. The mechanism has anonymity, un- forgeability and traceability, which is proved the security in the standard model. Simulationexperiments show that the proposed trusted attestation mechanism is flexible, practical and ef｜Scient and has better attack resistance. It can effectively guarantee the reliable data transmission of nodes and realize the dynamic tracking of node reliability, which has a lower impact on system performance.

关键词： internet of things: trusted mea-surement trusted attestation: group signature

Active manganese oxide on MnOx-CeO2 catalysts for low-temperature NO oxidation：Characterization and kinetics study

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Journal of Rare Earths 2018年第2期36卷 142-147页

作者： Lingkun Meng Jun Wang zhihui sun Jinxin Zhu Hang Li Jianqiang Wang Meiqing Shen Key Laboratory for Green Chemical Technology of State Education Ministry School of Chemical Engineering & Technology Tianjin UniversityTianjin 300072 China Collaborative Innovation Centre of Chemistry Science and Engineering (Tianjin) Tianjin 300072 China State Key Laboratory of Engines Tianjin University Tianjin 300072 China

MnO_x-CeO_2 catalysts were synthesized to investigate the active sites for NO oxidation by varying the calcination temperature. XRD and TEM results showed that cubic CeO_2 and amorphous MnO_x existed in MnO_x-CeO_2 catalysts. High temperature calcination caused the sintering of amorphous MnO_x and transforming to bulk crystalline Mn_2O_3, H_2-TPR and XPS results suggested the valence of Mn in MnO_x-CeO_2 was higher than pure MnO_x, and decreased with the increasing calcination temperature, The turnover frequency（TOF） was calculated based on the initial reducibility according to H_2-TPR quantitation and kinetic study. The TOF results indicated that the initial reducibility of amorphous MnO_x with high valence manganese ions was equivalent to the active sites for NO oxidation. It can be inferred that the amorphous MnO_x plays a key role in low-temperature NO oxidation.

关键词： MnOx-CeO2 NO oxidation Active manganese oxide Reaction kinetics Rare earths

Influence of Co, W and Ti on the Stress-rupture Lives of a Single Crystal Nickel-base Superalloy

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Journal of Materials Science & Technology 2006年第2期22卷 169-172页

作者： Dayun YANG Tao JIN Nairen ZHAO zhihui WANG Xiaofeng sun Hengrong GUAN Zhuangqi HU Department of Superalloy Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

The influence of Co, W and Ti on stress-rupture lives of a Ni-Cr-AI-Mo-Ta-Co-W-Ti single crystal nickel-base superalloy has been investigated using a L9 （34） orthogonal array design （OAD） by statistical analysis. At a selected composition range, Ti content was the most important factor to the effect of the stress-rupture lives and then followed by Co content. W content had the minimum effect on stress-rupture lives. The optimal alloy should contain 10 wt pct Co, 8 wt pct W and zero Ti. The optimized alloy also had good microstructural stability during thermal exposure at 870℃ for 500 h.

关键词： Nickel-base single crystal superalloy Orthogonal array design Stress-rupture