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Perturbation to Lie Symmetry and Lutzky Adiabatic Invariants for Lagrange Systems

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Communications in Theoretical Physics 2008年第1期49卷 57-60页

作者： DING ning FANG Jian-Hui WANG Peng ZHANG xiao-ni College of Physics Science and Technology China University of Petroleum Dongying 2570617 China

Based on the concept of adiabatic invariant, perturbation to Lie symmetry and Lutzky adiabatic invariants for Lagrange systems are studied by using different methods from those of previous works. Exact invariants induced from Lie symmetry of the system without perturbation are given. Perturbation to Lie symmetry is discussed and Lutzky adiabatic invariants of the system subject to perturbation are obtained.

关键词： symmetry perturbation Lutzky adiabatic invariant Lagrange system

Perturbation to Lie Symmetry and Hojman Exact and Adiabatic Invariants of Generalized Raitzin Canonical Equation of Motion

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Communications in Theoretical Physics 2007年第4X期48卷 615-618页

作者： WANG Peng FANG Jian-Hui DING ning ZHANG xiao-ni College of Physics and Technology China University of Petroleum Dongying 257061 China

In this paper, firstly, we get the Hojman exact invariants by Lie symmetry for an undisturbed generalized Raitzin equation of motion. Secondly, we study the perturbation to Lie symmetry of generalized Raitzin canonical equation of motion and get Hojman adiabatic invariants. Lastly, an example is given to illustrate the application of the results.

关键词： generalized mechanics symmetry Raitzin canonical equation perturbation adiabatic invariant

Above-threshold ionization of hydrogen atom in chirped laser fields

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Chinese Physics B 2018年第7期27卷 288-294页

作者： Yuan-Yuan ni Song-Feng Zhao xiao-Yong Li Guo-Li Wang xiao-Xin Zhou Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province College of Physics and Electronic Engineering Northwest Normal University Lanzhou 730070 China Experimental Center Northwest University for Nationalities Lanzhou 730030 China

Above-threshold ionization （ATI） of a hydrogen atom exposed to chirped laser fields is investigated theoretically by solving the time-dependent Schrodinger equation. By comparing the energy spectra, the two-dimensional momentum spectra, and the angular distributions of photoelectron for the laser pulses with different chirp rates, we show a very clear chirp dependence both in the multiphoton and tunneling ionization processes but no chirp dependence in the single-photon ionization. We find that the chirp dependence in the multiphoton ionization based ATI can be attributed to the excited bound states. In the single-photon and tunneling ionization regimes, the electron can be removed directly from the ground state and thus the excited states may not be very important. It indicates that the chirp dependence in the tunneling ionization based ATI processes is mainly due to the laser pulses with different chirp rates,

关键词： above-threshold ionization chirped laser field time-dependent Schrodinger equation

Molecular structure characterization of middle-high rank coal via^(13)C NMR,XPS,and FTIR spectroscopy

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China Geology 2024年第4期7卷 702-713页

作者： xiao-ming ni Jing-shuo Zhang xiao-kai Xu Bao-yu Wang School of Energy Science and Engineering Henan Polytechnic UniversityJiaozuo 454000China Institute of Resources&Environment Henan Polytechnic UniversityJiaozuo 454000China

Elemental analysis,nuclear magnetic resonance carbon spectroscopy(^(13)C-NMR),X-ray photoelectron spectroscopy(XPS)and Fourier transform infrared spectroscopy(FTIR)experiments were carried out to determine the existence of aromatic structure,heteroatom structure and fat structure in ***(materials studio)software was used to optimize and construct a 3D molecular structure model of coal.A method for establishing a coal molecular structure model was formed,which was“determination of key structures in coal,construction of planar molecular structure model,and optimization of three-dimensional molecular structure model”.The structural differences were compared and *** results show that with the increase of coal rank,the dehydrogenation of cycloalkanes in coal is continuously enhanced,and the content of heteroatoms in the aromatic ring *** heteroatoms and branch chains in the coal are reduced,and the structure is more orderly and *** stability of the structure is determined by theπ-πinteraction between the aromatic rings in the nonbonding energy *** Stretching Energy The size of EB determines how tight the structure *** research results provide a method and reference for the study of the molecular structure of medium and high coal ranks.

关键词： Molecular structure model Carbon-13 nuclear magnetic resonance(NMR) X-ray photoelectron spectroscopy(XPS) Fourier transform infrared spectroscopy(FTIR) Coal

200-nm long TiO_2 nanorod arrays for efficient solid-state Pb S quantum dot-sensitized solar cellsR

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Journal of Energy Chemistry 2018年第4期27卷 1214-1218页

作者： Zhengguo Zhang Chengwu Shi Kai Lv Chengfeng Ma Guannan xiao Lingling ni School of Chemistry and Chemical Engineering Hefei University of TechnologyHefei 230009AnhuiChina School of Chemistry and Chemical Engineering Beifang University of NationalitiesYinchuan 750021NingxiaChina

To ensure the infiltration of spiro-OMeTAD into the quantum dot-sensitized photoanode and to consider the limit of the hole diffusion length in the spiro-OMeTAD layer, a rutile TiO2 nanorod array with a length of 200 nm, a diameter of 20 nm and an areal density of 720 ram 2 was successfully prepared using a hydrothermal method with an aqueous-grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 ℃ for 75 min. PbS quantum dots were deposited by a spin coating-assisted successive ionic layer adsorption and reaction （spin-SILAR）, and all solid-state PbS quantum dot-sensitized TiO2 nanorod array solar cells were fabricated using spiro-OMeTAD as electrolytes. The results revealed that the average crystal size of PbS quantum dots was -78 nm using Pb（NO3）2 as the lead source and remain unchanged with the increase of the number of spin-SILAR cycles. The all solid-state PbS quantum dot-sensitized TiO2 nanorod array solar cells with spin-SILAR cycle numbers of 20, 30 and 40 achieved the photoelectric conversion efficiencies of 3.74%, 4.12% and 3.11%, respectively, under AM 1.5 G illumination （100 mW/cm2）.

关键词： TiO2 nanomd array PbS quantum dot Spiro-OMeTAD All solid-state sensitized solar cell

Anti-Interference Low-Power Double-Edge Triggered Flip-Flop Based on C-Elements

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Tsinghua Science and Technology 2022年第1期27卷 1-12页

作者： Zhengfeng Huang xiao Yang Tai Song Haochen Qi Yiming Ouyang Tianming ni Qi Xu School of Electronic Science and Applied Physics Hefei University of TechnologyHefei 230601China School of Computer and Information Hefei University of TechnologyHefei 230601China School of Electrical Engineering Anhui Polytechnic UniversityWuhu 241000China

When the input signal has been interfered and glitches occur,the power consumption of Double-Edge Triggered Flip-Flops(DETFFs)will significantly *** effectively reduce the power consumption,this paper presents an anti-interference low-power DETFF based on *** improved C-element is used in this DETFF,which effectively blocks the glitches in the input signal,prevents redundant transitions inside the DETFF,and reduces the charge and discharge frequencies of the *** C-element has also added pull-up and pull-down paths,reducing its *** with other existing DETFFs,the DETFF proposed in this paper only flips once on the clock edge,which greatly reduces the redundant transitions caused by glitches and effectively reduces power *** paper uses HSPICE to simulate the proposed DETFF and other 10 *** findings show that compared with the other 10 types of DETFFs,the proposed DETFF has achieved large performance indexes in the total power consumption,total power consumption with glitches,delays,and power delay product.A detailed analysis of variance indicates that the proposed DETFF features less sensitivity to process,voltage,temperature,and Negative Bias Temperature Instability(NBTI)-induced aging variations.

关键词： Double-Edge Triggered Flip-Flop(DETFF) glitch low-power C-element

Visualization of MF/Diesel RCCI Combustion Process and Soot Emission

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Journal of Thermal Science 2024年第2期33卷 779-792页

作者： HUANG Chen ni xiao GE Dameng LI Song ZHANG Wanzhi LIU Jinping ZHANG Tingting School of Mechanical and Electronic Engineering Shandong Agricultural UniversityTaian271018China Shandong Provincial Engineering Laboratory of Agricultural Equipment Intelligence Taian271018China Taian Technician Institute Taian271000China Sinotruk Taian Wuyue Special Vehicle Co. Ltd.Taian271000China School of Mechanical Engineering Shaanxi University of TechnologyHanzhong723001China School of Mechanical Engineering Anyang Institute of TechnologyAnyang455000China

Based on the optical engine,the ignition characteristics,combustion process and soot emission characteristics of diesel under different 2-Methylfuran(MF) atmospheres were investigated by high-speed photography and in-cylinder combustion analysis *** results show that at the same main injection timing,the ignition time of reactivity controlled compression ignition(RCCI) combustion mode is earlier than pure diesel combustion,and the ignition point is concentrated near the *** acts as a spark plug to ignite the mixture,but the flame develops slowly in the early stages and the pressure in the cylinder rises *** with pure diesel,RCCI combustion model has smaller peak values of in-cylinder pressure and heat release rate,shorter ignition delay period,earlier combustion phase and shorter combustion *** main spray time at 6℃A BTDC and 12℃A BTDC,with the increase of MF premixing ratio from 0 to 0.75,the peak cylinder pressure decreased by 19.6% and 26% *** addition,with the increase of the MF heat value ratio,the area of KL factor> 1.5 in the combustion chamber decreased and the space integral natural luminescence(SINL) peak value decreased by 48.37%,and the soot formation rate and yield decreased ***,when the MF heat value ratio was too large(75% of the total calorific value),the ignition delay period increased,and misfire occurred at the main injection timing of 0℃A *** RCCI mode of MF/diesel dual fuel has better stability,and better control effect can be obtained at different main inj ection timing.

关键词： 2-methylfuran RCCI visualization two-color method KL factor

Accelerated kinetics of alkaline hydrogen evolution/oxidation reactions on dispersed ruthenium sites through N and S dual coordination

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Science China Chemistry 2022年第3期65卷 611-618页

作者： Zhen Zhang Liwen ni Haijun Liu Zhi-Liang Zhao xiao-Zi Yuan Hui Li School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Department of Materials Science and Engineering Shenzhen Key Laboratory of Hydrogen EnergySouthern University of Science and TechnologyShenzhen 518055China Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen 518055China Research Center of Energy Mining and EnvironmentNational Research Council Canada4250 Wesbrook MallVancouver V6T1W5Canada

Efficient,robust and cost-effective electrocatalysts that catalyze hydrogen evolution/oxidation reaction(HER/HOR)in alkaline media are highly ***,single-atom catalysts(SACs)have emerged as new promising candidates;however,the rational design of supports and the optimization of coordination environment between supports and metal atoms are *** this work,we successfully fabricate atomically dispersed ruthenium(Ru)species,which are strongly coordinated by N and S dual heteroatoms on holey graphene(RuSA/NSG),as an excellent bifunctional catalyst for HER/*** alkaline media,the developed catalyst exhibits high catalytic performance with a low overpotential of 57.3 mV to drive a current density of 10 mA cm^(-1) for HER,and its mass activity is about 5.8 times higher than that of commercial Pt/C and Ru/C catalysts at an overpotential of 100 ***,considerable HOR performance of Ru SA/NSG is verified to be superior to Pt/C and Ru/***,X-ray-based spectroscopy measurements and density-functional theory calculations have confirmed that,compared with Ru–N_(4),the tailored Ru–N_(4)–S_(2) with nearby S dopants can act as more active centers to greatly accelerate the sluggish HER/HOR kinetics in alkaline *** present work provides a new atomic-level engineering strategy to modulate catalytic activities of SACs via the coordination design using dual heteroatoms on the carbon support.

关键词： single-atom catalyst ruthenium hydrogen evolution reaction hydrogen oxidation reaction density-functional theory

Relationship between elements migration ofα-AlFeMnSi phase and micro-galvanic corrosion sensitivity of Al-Zn-Mg alloy

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International Journal of Minerals,Metallurgy and Materials 2023年第1期30卷 112-121页

作者： Min Ao Yucheng Ji Pan Yi ni Li Li Wang Kui xiao Chaofang Dong Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China China Electric Power Research Institute Beijing 100192China

First principles calculations and scanning Kelvin probe force microscopy(SKPFM)were used to investigate the effect of elements migration ofα-AlFeMnSi phase on micro-galvanic corrosion behavior of Al-Zn-Mg *** simulation results showed that the average work function difference between theα-AlFeMnSi phase and Al matrix decreased from 0.232 to 0.065 eV due to the synchronous migration of elements ***,as the elements Fe-Si migration during the extrusion process,the average Volta potential difference detected by SKPFM between theα-AlFeMnSi phase and Al matrix dropped down to 432.383 mV from 648.370 ***,the elements migration reduced the micro-galvanic corrosion sensitivity of Al-Zn-Mg *** reach the calculated low micro-galvanic tendency betweenα-AlFeMnSi phase and Al matrix,the diffusion of Mn should be promoted during extruding process.

关键词： Al-Zn-Mg alloy corrosion behavior α-AlFeMnSi phase first principles calculations