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A visible-light-assisted Pd/TiO_(2)gas sensor with carbon nanotubes electrodes for trace formaldehyde detection

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Rare Metals 2024年第1期43卷 257-266页

作者： can liu Qiao-Qiao Zou Bin liu Yong Zhang School of Physics and Optoelectronics Xiangtan UniversityXiangtan 411105China Hunan Institute of Advanced Sensing and Information Technology Xiangtan UniversityXiangtan 411105China School of Materials Science and Engineering Xiangtan UniversityXiangtan 411105China

Owing to the ppb-level detection standard toward the toxic and harmful gas,the detection of trace gases has become an important subject in the field of indoor environment ***,the traditional resistive gas sensors hardly meet the requirement due to the weak signal generated by trace gas molecules that are difficult to ***,a visible-light-assisted Pd/TiO_(2)gas sensor is proposed to endow the effective detection of trace formaldehyde(HCHO)gas without heating *** from the enhanced photocatalytic properties of TiO_(2)by Pd decoration,the visible-light-assisted Pd/TiO_(2)gas sensor can detect the HCHO gas as low as80×10^(–9)at room *** successful preparation of nanoscale TiO_(2)sensing layer is facilitated by the ultrathin carbon nanotube interdigital electrode in the gas sensor,which avoids the discontinuity of the sensing layer caused by the excessive thickness of the traditional metal *** addition,the whole preparation process of the Pd/TiO_(2)gas sensor with carbon nanotube electrodes is compatible with mainstream CMOS fabrication technology,which is expected to realize the batch fabrication and micro-integrated application of gas *** is expected that our work can provide a new strategy for the batch preparation of high-performance trace HCHO gas sensors and their future applications in portable electronic devices such as smartphones.

关键词： Visible-light-assisted gas sensor Pd/TiO_(2) Trace HCHO detection Carbon nanotubes electrodes

Influence of Blade Outlet Angle on Inner Flow Field of Centrifugal Pump Transporting Salt Aqueous Solution

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Chinese Journal of Mechanical Engineering 2009年第6期22卷 912-917页

作者： YANG Minguan KANG can DONG Xiang liu Dong School of Energy and Power Engineering Jiangsu University Zhenjiang 212013 China

During transportation of salt aqueous solutions with centrifugal pump, crystallization phenomenon is frequently encountered. For this kind of two-phase flow, it is difficult to be accurately modeled since there are various medium properties and phase change characteristics. In view of experiment, several problems are hampering the implementation of precise measurement. Influences of blade outlet angle and medium temperature on crystallization rate were studied. Sodium sulfate solution was applied to simulate practical fluid in chemical industry. Particle image velocimetry（PIV） was employed to measure velocity distributions in rotating impeller. Crystallization processes in three impellers with different blade outlet angles were investigated. Relations among crystallization and flow parameters such as temperature and velocity were obtained. With the same blade wrap angle, when blade outlet angle is larger, diffusion of single flow passage gets stronger, relative velocity at blade outlet decreases and large scale vortex tends to appear near the blade working surface. For the impact of volume effect of particle phase on fluid viscosity, both liquid and solid phase velocities decrease with continual forming and growing of crystal particles. Velocity of solid phase is greater than that of liquid phase and its direction leans more closely to blade working surface. Solid particles tend to move towards blade working surface, as is more obvious in the impeller with large blade outlet angle. Therefore, collision between solid particles with stem part of blade working surface is more intensive in impeller with large blade outlet angle. Concerning transportation of salt aqueous solution, accurate PIV measurement is conducted in centrifugal impellers with different blade outlet angles. The results are useful and instructive in relevant engineering design and operation.

关键词： centrifugal pump flow with crystallization blade outlet angle particle image velocimetry(PIV)

Influence of lanthanum on inclusions and as-cast microstructures in a low-alloy high-strength steel

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Journal of Iron and Steel Research International 2023年第12期30卷 2471-2481页

作者： can liu Ji Zhang Qiang Ren Li-feng Zhang School of Materials Science and Engineering Yanshan UniversityQinhuangdao066004HebeiChina School of Metallurgical and Ecological Engineering University of Science and Technology Beijing(USTB)Beijing100083China School of Mechanical Engineering Yanshan UniversityQinhuangdao066004HebeiChina School of Mechanical and Materials Engineering North China University of TechnologyBeijing100144China

Advanced high-strength steel ingots with total lanthanum(TLa)contents of 0,15×10^(–6),86×10^(–6)and 360×10^(–6)were prepared through laboratory *** modification of inclusions and the variation of the as-cast microstructure with the content of lanthanum in the high-strength steel were *** result showed that with the increase in the TLa content in the steel from 0 to 360×10^(–6),the modification path of inclusions in the as-cast steel was Al2O_(3)and calcium aluminate→LaAlO_(3)→La_(2)O_(2)S→La_(2)O_(2)S–La2O_(3).The addition of La in the high-strength steel significantly refined the solidification *** the increase in the TLa content in the steel from 0 to 360×10^(–6),the ratio of the equiaxed crystal region in the macrostructure increased from 30.1%to 50.7%,the proportion of the high-angle grain boundary in the microstructure increased from 36.9%to 69.8%,and the area fraction of the acicular ferrite and the bainite increased from 0 to 93.3%.Inclusions of LaAlO_(3),La_(2)O_(2)S and La2O_(3)in the La-containing steel could act as heterogeneous nucleation cores ofα-Fe during the *** the increase in the TLa content in the steel,the number density of inclusions that could act as effective heterogeneous nucleation cores in the steel gradually increased,which enlarged the ratio of the equiaxed crystal region and the proportion of intragranular acicular ferrite,and refined the as-cast microstructure of the high-strength steel.

关键词： Advanced high-strength steel Lanthanum Inclusion Heterogeneous nucleation As-cast microstructure

Dynamic properties of the two-dimensional density-driven segregation

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Communications in Theoretical Physics 2020年第7期72卷 111-115页

作者： Yao-Dong Feng can-can liu Qing-Fan Shi Gang Sun Department of Physics Beijing Institute of TechnologyBeijing 100081China Beijing Key Laboratory for Nanomaterials and Nanodevices Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China

We discuss some dynamic properties of the segregation in vertically vibrated binary granular mixtures with the same *** present a method that can accurately calculate the order parameter in the *** use of the time evolution of the order parameter,we have found that the convergence of the segregated state depends at least on the vibration amplitude,the total mass of the particles,and also the density difference between the lighter and heavier *** convergence is quicker for larger vibration amplitude,lighter total mass of the particles and more density difference between the lighter and heavier *** have also found that thefluctuation is larger even after the steady state is reached for lighter total mass of the particles and less density difference between the lighter and heavier particles.

关键词： granular matter segregation effect molecular dynamic simulation

Synthesis of a Newly Modified Poly-H8-BINOL Ligand and Its Applications in the Asymmetric Addition of Triethylalumininm to Aromatic Aldehydes

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Chemical Research in Chinese Universities 2017年第5期33卷 742-745页

作者： liu can OUYANG Kunbing YANG Nianfa Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education College of Chemistry Xiangtan University Xiangtan 411105 R R. China

A new H8-BINOL polymer was synthesized by radical polymerization and proved to be an effective cata- lyst in enantioselective addition of triethylaluminium to aromatic aldehydes in the presence of titanium isopropoxide. The polymer can be prepared with simple steps and reused without losing its enantioselectivity and catalytic activity.

关键词： H8-BINOL Radical polymerization Triethylaluminium Asymmetric addition Enantioselectivity

Influencing mechanism of high solid concentration on anaerobic mono-digestion of sewage sludge without agitation

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Frontiers of Environmental Science & Engineering 2015年第6期9卷 1108-1116页

作者： Yuyao ZHANG Huan LI can liu Yingchao CHENG Key Laboratory of Microorganism Application and Risk Control of Shenzhen Graduate School at Shenzhen Tsinghua University Shenzhen 518055 China

High-solids anaerobic digestion of sewage sludge was a promising process, but high solid concentra- tion negatively influenced methane production. The influencing mechanism was systematically analyzed in this study through a series of static anaerobic digestion experiments at total solids （TS） contents of 3%--15%. The results showed that TS 6% was the boundary between low- solids and high-solids anaerobic digestion, and the accumulative methane yield decreased exponentially when TS increased from 6% to 15%. The performance of anaerobic digestion was directly determined by the efficiency of mass transfer, and the relation between methane yield and sludge diffusive coefficients was well described by a power function. Thus, the increasing TS resulted in an exponential increase in sludge viscosity but an exponential decrease in diffusive coefficient. The blocked mass transfer led to the accumulation of volatile fatty acids （VFAs） and free ammonia. Acetic metabolism was the main process, whereas butyric and propionic metabolisms occurred at the initial stage of high-solids anaerobic digestion. The concentration of VFAs reached the maximum at the initial stage, which were still lower than the threshold influencing methanogens. The concen- tration of free ammonia increased gradually, and the methanogenesis was inhibited when free ammonia nitro- gen exceeded 50 mg.L^-1. Consequently, the deterioration of high-solids anaerobic digestion was related to the blocked mass transfer and the resulting ammonia accumu- lation.

关键词： anaerobic digestion methane sewage sludge,volatile fatty acids free ammonia

A Computer-Aided Tuning Method for Microwave Filters by Combing T-S Fuzzy Neural Networks and Improved Space Mapping

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Computer Modeling in Engineering & Sciences 2018年第9期116卷 433-453页

作者： Shengbiao Wu Weihua Cao can liu Min Wu School of Automation China University of GeoscienceWuhanHubei430074China Nanchang Institute of Science and Technology.Nanchang Jiangxi330100China The Hubei key Laboratory of Advanced Control and Intelligent Automation for Complex Systems WuhanHubei430074China

A computer-aided tuning method that combines T-S fuzzy neural network(TS FNN)and offers improved space mapping(SM)is presented in this *** method consists of three main ***,the coupling matrix is effectively extracted under the influence of phase shift and cavity loss after the initial ***,the surrogate model is realized by using a T-S FNN based on subspace ***,the mapping relationship between the actual and the surrogate models is established by the improved space mapping algorithm,and the optimal position of the tuning screws are found by updating the input and output parameters of the surrogate ***,the effectiveness of different methods is verified by an experiment with a nine order cross coupled *** results show that,compared to a back propagation neural network method based on electromagnetic simulation and an SM method based on a least squares support vector machine,the proposed method has obvious advantages in terms of tuning accuracy and tuning time.

关键词： Computer-aided tuning T-S FNN S-parameters coupling matrix

Mechanically exfoliated MoS_(2) nanosheets decorated with SnS_(2) nanoparticles for high-stability gas sensors at room temperature

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Rare Metals 2021年第6期40卷 1536-1544页

作者： Jia-Bei liu Jin-Yong Hu can liu Yu-Ming Tan Xiang Peng Yong Zhang School of Physics and Optoelectronics Xiangtan UniversityXiangtan 411105China Hunan Institute of Advanced Sensing and Information Technology Xiangtan UniversityXiangtan 411105China

Due to its unique physical,chemical and surface electronic properties,molybdenum disulfide(MoS_(2))nanosheets open up a new avenue for nitrogen dioxide(NO2)detection at room ***,the gas sensing properties of pure MoS_(2) nanosheets are inevitably degenerated by the adsorption of atmospheric oxygen,which results in weak stability for MoS_(2)-based gas *** surface defects and constructing heterojunctions may be effective strategies to improve the gas sensing properties of MoS_(2) *** this work,we design a novel nanocomposite based on MoS_(2) nanosheets decorated with tin disulfide(SnS_(2))nanoparticles(MoS_(2)/SnS_(2))via combining the mechanical exfoliation method with the facile hydrothermal *** experimental results indicate that,after surfaces decoration with SnS_(2) nanoparticles,the as-prepared gas sensor based on MoS_(2)/SnS_(2) nanocomposites exhibits reliable long-term stability with the maximum response value drift of less than 3%at room ***,the MoS_(2)/SnS_(2) sensor also possesses desirable gas sensing properties upon NO_(2) at room temperature,such as high sensitivity,rapid response/recovery speed(28 s/3 s,5×10^(-6) NO_(2)),satisfactory selectivity,favorable repeatability and *** improved gas sensing properties of MoS_(2)/SnS_(2) nanocomposites can be attributed to the unique electronic properties of MoS 2 nanosheets with the fewer layers structure and the competitive adsorption effect of SnS_(2) *** work elucidates that SnS_(2) nanoparticles serving as an effective antioxidative decoration can promote the stability of MoS_(2) nanosheets,providing a promising approach to achieve high-stability NO2 gas sensors at room temperature.

关键词： Mechanically exfoliated MoS2 nanosheets MoS_(2)/SnS_(2)nanocomposites NO2 sensing properties Room-temperature detection

An Improved Approach for Interaction of Wave with Floating Spheres and Its Applications

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China Ocean Engineering 2023年第1期37卷 115-130页

作者： liu can DONG Zhi-yong PAN Yun TONG Huan-huan YANG li-jing College of Civil Engineering Zhejiang University of TechnologyHangzhou 310023China School of Naval Architecture and Maritime Zhejiang Ocean UniversityZhoushan 316022China School of Marine Engineering Equipments Zhejiang Ocean UniversityZhoushan 316022China

To develop and utilize marine resources in the deep sea, the higher requirements for floating structures, which are operated in marine environment for a long term, have been put forward. Reasonable structure type and accurate force analysis are favorable guarantees to improve the survival performance and working performance of the floating structures. Floating spheres fastened by mooring cable were widely used in floating structures. In this paper, the wave forces of the floating sphere are efficiently and accurately calculated by solving the geometric relationship between the non-submerged floating sphere and wave surface. Combined with the hydrodynamic calculation of mooring cables based on the lumped mass method, the coupled motion model of multi-floating spheres fastened by multi-mooring cable was established under wave action. Furthermore, according to the floating structures fastened by mooring cable in the actual ocean engineering, the topological method of multi-mooring cables fastening the multifloating spheres was expounded from simple to complex. Finally, the modeling method and preliminarily hydrodynamic characteristics of the fastened floating structures, including the mooring system of renewable energy devices, ocean buoy, and coral nursery, were presented and analyzed in detail. The obtained results showed that the method for calculating the wave force on the floating sphere developed in this paper can accurately describe the motion process of the floating mooring sphere and the force on the mooring cable. Also, the topological method of multiple buoys and multiple mooring cables could efficiently establish various numerical hydrodynamic models of fastened buoys in ocean engineering.

关键词： floating sphere mooring cable wave forces hydrodynamic model ocean engineering