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Multilevel atomic Ramsey interferometry for precise parameter estimations

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Chinese Physics B 2021年第12期30卷 321-328页

作者： X N Feng l F wei Guangdong Provincial Key laboratory of Quantum Metrology and Sensing&School of Physics and Astronomy Sun Yat-Sen University(Zhuhai Campus)Zhuhai 519082China Information Quantum Technology laboratory School of Information Science and TechnologySouthwest Jiaotong UniversityChengdu 610031China

Multi-path(or multi-mode)entanglement has been proved to be a useful resource for sub-shot-noise sensitivity of phase estimation,which has aroused much research interest in quantum metrology *** schemes of multi-path interferometers based on optical systems have been put ***,we study a multi-state interferometer with multilevel atoms by projective ***,we investigate its ultimate sensitivity described by quantum Fisher information theory and find that the Cramer-Rao bound can be *** particular,we investigate a specific scheme to improve the sensitivity of magnetometery with a three-state interferometry delivered by a single nitrogen-vacancy(NV)center of diamond with tailor *** impacts of imperfections of the atomic beam-splitter,described by the three-level quantum Fourier transform,on the sensitivity of phase estimation is also discussed.

关键词： quantum metrology multi-path interferometers quantum measurement

Finite element analysis of multi-piece post-crown restoration using different types of adhesives

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International Journal of Oral Science 2013年第3期5卷 162-166页

作者： lin-wei l Guang-wei Meng Zhi-Hui liu Department of Engineering Mechanics Jilin University Hospital of Stomatology

The multi-piece post-crown technique is more effective in restoring residual root than other restoration *** types of adhesives have different material properties that affect ***,the choice of adhesive is particularly important for ***,the effect of different kinds of adhesives was not too precise by experimental methods when concerning about individual differences of *** tooth root can only be restored with one type of adhesive in *** the mechanical test,this tooth root cannot be restored with other *** the help of medical imaging technology,reverse engineering and finite element analysis,a molar model can be reconstructed precisely and restored using different types of *** same occlusal and chewing loads were exerted on the same restored residual root models with different types of adhesives *** of von Mises stress analysis showed that the adhesives with low Young’s modulus can protect the root canal ***,a root canal concentration is apparently produced around the root canal orifice when *** with large Young’s modulus can buffer the stress concentration of the root canal ***,the root canal tissue may be destroyed because the adhesive is too hard to buffer the load.

关键词： adhesive finite element analysis molar restoration multi-piece post-crown stomatology

Multiscale and multiphysics explorations of the transient deposition processes and additive characteristics during laser 3D printing

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Journal of Materials Science & Technology 2021年第18期77卷 196-208页

作者： H.l.wei F.Q.liu l.wei T.T.liu W.H.liao School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing.210094China State Key laboratory of Solidification Processing Northwestern Poly technical UniversityXi'an710072China

laser directed energy deposition(DED)involves complex physical processes,and the trial and error examinations are time consuming and cost *** research paradigm can be reshaped using advanced phenomenological models via computing the spatiotemporal variations of the build *** this work,multi-layer and multi-track laser DED of Ti-6 Al-4 V were systematically explored on multiple scales including the 1D track,the 2D layer and the 3D full build considering the complex transport of energy,mass,and momentum in the moving freeform molten *** results showed that convex,nearflat,and wavy builds were generated using gradually larger hatch *** profiles of individual tracks and layers were extracted through the unique advantages of the *** individual tracks exhibited various patterns and rotated with specific inclinations to form distinct layer *** net increments of the deposit generated upon the printing of a new track during the continuous deposition process showed that the smaller hatch spacing caused higher overlap rate of horizontally adjacent tracks but lower remelting rate of vertically adjacent tracks in neighboring *** 3D numerical model was validated with corresponding experiments for various process *** scientific findings can provide useful insights for further researches of DED.

关键词： Additive manufacturing Multi-layer and multi-track Numerical model Build features Molten pool

Speeding up transmissions of unknown quantum information along Ising-type quantum channels

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Chinese Physics B 2017年第1期26卷 125-130页

作者： W J Guo l F wei Quantum Optoelectronics laboratory Southwest Jiaotong University Chengdu 610031 China State Key laboratory of Optoelectronic Materials and Technologies School of Physics Sun Yat-Sen University Guangzhou 510275 China

Quantum teleportation with entanglement channels and a series of two-qubit SWAP gates between the nearestneighbor qubits are usually utilized to achieve the transfers of unknown quantum state from the sender to the distant receiver. In this paper, by simplifying the usual SWAP gates we propose an approach to speed up the transmissions of unknown quantum information, specifically including the single-qubit unknown state and two-qubit unknown entangled ones,by a series of entangling and disentangling operations between the remote qubits with distant interactions. The generic proposal is demonstrated specifically with experimentally-existing Ising-type quantum channels without transverse interaction; liquid NMR-molecules driven by global radio frequency electromagnetic pulses and capacitively-coupled Josephson circuits driven by local microwave pulses. The proposal should be particularly useful to set up the connections between the distant qubits in a chip of quantum computing.

关键词： unknown quantum information transfers Ising-type quantum chains NMR molecules superconducting circuits

Isothermal reduction kinetics of Panzhihua ilmenite concentrate under 30vol% CO–70vol% N2 atmosphere

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International Journal of Minerals,Metallurgy and Materials 2017年第3期24卷 240-248页

作者： Ying-yi Zhang wei lü Xue-wei lü Sheng-ping li Chen-guang Bai Bing Song Ke-xi Han College of Materials Science and Engineering Chongqing University Chongqing 400044 China Panzhihua Iron and Steel Research Institute Panzhihua 617000 China

The reduction of ilmenite concentrate in 30vol% CO–70vol% N_2 atmosphere was characterized by thermogravimetric and differential thermogravimetric(TG–DTG) analysis methods at temperatures from 1073 to 1223 *** isothermal reduction results show that the reduction process comprised two stages;the corresponding apparent activation energy was obtained by the iso-conversional and model-fitting *** the first stage,the effect of temperature on the conversion degree was not obvious,the phase boundary chemical reaction was the controlling step,with an apparent activation energy of 15.55–40.71 k J·mol^(–1).For the second stage,when the temperatures was greater than 1123 K,the reaction rate and the conversion degree increased sharply with increasing temperature,and random nucleation and subsequent growth were the controlling steps,with an apparent activation energy ranging from 182.33 to 195.95 k J·mol^(–1).For the whole reduction process,the average activation energy and pre-exponential factor were 98.94^(–1)18.33 k J·mol^(–1) and 1.820^(–1).816 min^(–1),respectively.

关键词： ilmenite isothermal reduction kinetics carbon monoxide

Theory and Practice of the SSDM for GPS Deformation Monitoring

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Journal of China University of Mining and Technology 2006年第2期16卷 156-161页

作者： lü wei-cai XU Shao-quan Department of Resource and Environment Engineering Anhui University of Science and Technology Huainan Anhui 232001 China School of Geodesy and Geomatics Wuhan University Wuhan Hubei 430079 China

Global Positioning System technique is widely used to monitor the deformations of all kinds of buildings and constructions. According to the characteristics of the high precise GPS deformation monitoring, the theory and practice of the SSDM （Similar Single-Difference Methodology） for GPS deformation monitoring are introduced synthetically from the background, the essential mathematic model,the error sources and control measures, the monitoring schemes and the software development. Some arguments are also given in the form of reference literatures. Based on the first period observation results of the GPS monitor network, SSDM solves the monitoring points＇ deformation values at a single epoch from carder phases directly, without needing to solve baseline vectors and network adjustment. The SSDM avoids the troublesome problem of detecting and repairing cycle slips, and can be used in static and dynamic deformation monitoring. In the SSDM, the unknown parameters have no relation to the numbers of satellites. If the number of synchronous satellites between stations is not less than two, the monitoring point＇s deformation information can be solved easily.

关键词： GPS Deformation monitoring Single epoch SSDM Methodology Summarization

Preparation of ferronickel from nickel laterite via coal-based reduction followed by magnetic separation

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International Journal of Minerals,Metallurgy and Materials 2018年第7期25卷 744-751页

作者： lun-wei Wang Xue-ming Mei liu Zhi-xiong You Xue-wei Chen-guang Bai college of materials science and engineering chongqing universityChongqing 400044China engineer of cisdi thermal&environmental engineering co. ltd.Chongqing 401122China

The sticking phenomenon between molten slag and refractory is one of the crucial problems when preparing ferronickel from laterite ore using rotary hearth fulnace or rotary kiln processes. This study aims to ameliorate sticking problems by using silicon dioxide （SiO2） to adjust the melting degree of file briquette during reduction roasting. Thermodynamic analysis indicates that the melting temperature of the slag gradually increases with an increase in the SiO2 proportion （SiO2/（SiO2 ＋ A1203 ＋ MgO） mass ratio）. Experimental validations also prove that the briquette retains its original shape when the SiO2 proportion is greater than 75wt%, and sticking problems axe avoided during reduction. A ferronickel product with 8.33wt% Ni and 84.71wt% Fe was prepared via reductive roasting at 1500~C for 90 min with a SiO2 proportion of 75wt% and a C/O molar ratio of 1.0 followed by dry magnetic separation; the corresponding recoveries of Ni and Fe reached 75.70% and 77.97%, respectively. The micro stxucture and phase txmlsformation of reduced briquette reveals that the aggregation and growth of ferroinckel particles were not significantly affected after adding SiO2 to the reduction process.

关键词： nickel laterite caxbot^ermal reduction ferronickel magnetic separation

Recovery of iron and calcium aluminate slag from high-ferrous bauxite by high-temperature reduction and smelting process

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International Journal of Minerals,Metallurgy and Materials 2016年第8期23卷 881-890页

作者： Ying-yi Zhang wei lü Yuan-hong Qi Zong-shu Zou College of Materials Science and Engineering Chongqing University State Key laboratory of Advance Steel Processes and Products Central Iron and Steel Research Institute School of Material and Metallurgy Northeastern University

A high-temperature reduction and smelting process was used to recover iron and calcium aluminate slag from high-ferrous bauxite. The effects of w（CaO）/w（SiO_2） ratio, anthracite ratio, and reduction temperature and time on the recovery and size of iron nuggets and on the Al_2O_3 grade of the calcium aluminate slag were investigated through thermodynamic calculations and experiments. The optimized process conditions were the bauxite/anthracite/slaked lime weight ratio of 100：16.17：59.37, reduction temperature of 1450°C and reduction time of 20 min. Under these conditions, high-quality iron nuggets and calcium aluminate slag were obtained. The largest size and the highest recovery rate of iron nuggets were 11.42 mm and 92.79wt%, respectively. The calcium aluminate slag mainly comprised Ca_2 SiO_4 and Ca_（12）Al_（14）O_（33）, with small amounts of Fe Al_2O_4, CaAl_2O_4, and Ca_2Al_2SiO_7.

关键词： bauxite reduction smelting recovery rate calcium aluminate slag

Isothermal reduction of titanomagnetite concentrates containing coal

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International Journal of Minerals,Metallurgy and Materials 2014年第2期21卷 131-137页

作者： Tu Hu Xue-wei lü Chen-guang Bai Gui-bao Qiu College of Materials Science and Engineering Chongqing University Faculty of Metallurgical and Energy Engineering Kunming University of Science and Technology

The isothermal reduction of the Panzhihua titanomagnetite concentrates （PTC） briquette containing coal under argon atmosphere was investigated by thermogravimetry in an electric resistance furnace within the temperature range of 1250-1350°C. The samples reduced in argon at 1350°C for different time were examined by X-ray diffraction （XRD） analysis. Model-fitting and model-free methods were used to evaluate the apparent activation energy of the reduction reaction. It is found that the reduction rate is very fast at the early stage, and then, at a later stage, the reduction rate becomes slow and decreases gradually to the end of the reduction. It is also observed that the reduction of PTC by coal depends greatly on the temperature. At high temperatures, the reduction degree reaches high values faster and the final value achieved is higher than at low temperatures. The final phase composition of the reduced PTC-coal briquette consists in iron and fer-rous-pseudobrookite （FeTi2O5）, while Fe2.75Ti0.25O4, Fe2.5Ti0.5O4, Fe2.25Ti0.75O4, ilmenite （FeTiO3） and wustite （FeO） are intermediate products. The reaction rate is controlled by the phase boundary reaction for reduction degree less than 0.2 with an apparent activation energy of about 68 kJ·mol-1 and by three-dimensional diffusion for reduction degree greater than 0.75 with an apparent activation energy of about 134 kJ·mol-1. For the reduction degree in the range of 0.2-0.75, the reaction rate is under mixed control, and the activation energy increases with the increase of the reduction degree.

关键词： titanomagnetite carbothermal reduction thermogravimetric analysis kinetics