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Experimental and Numerical Investigation on the Aerodynamic Characteristics of High-Speed Pantographs with Supporting Beam Wind Deflectors
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作者 Shiyang Song Tongxin Han 《Fluid Dynamics & Materials Processing》 EI 2024年第1期127-145,共19页
Aiming to mitigate the aerodynamic lift force imbalance between pantograph strips,which exacerbates wear and affects the current collection performance of the pantograph-catenary system,a study has been conducted to s... Aiming to mitigate the aerodynamic lift force imbalance between pantograph strips,which exacerbates wear and affects the current collection performance of the pantograph-catenary system,a study has been conducted to support the beam deflector optimization using a combination of experimental measurements and computational fluid dynamics(CFD)simulations.The results demonstrate that the size,position,and installation orientation of the wind deflectors significantly influence the amount of force compensation.They also indicate that the front strip deflectors should be installed downwards and the rear strip deflectors upwards,thereby forming a“π”shape.Moreover,the lift force compensation provided by the wind deflectors increases with the size of the deflector.Alternative wind compensation strategies,such as control circuits,are also discussed,putting emphasis on the pros and cons of various pantograph types and wind compensation approaches. 展开更多
关键词 High-speed pantograph aerodynamic lift force supporting beam wind deflectors computational fluid dynamics(CFD)
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High Resolution Crossed Molecular Beams Study on the F+HD→HF+D Reaction at Collision Energy of 8.19-18.98 kJ/mol 被引量:1
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作者 董文锐 肖春雷 +3 位作者 汪涛 戴东旭 王秀岩 杨学明 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2011年第5期521-528,I0003,共9页
The crossed beams scattering dynamics of the F+HD→HF+D reaction have been studied at collision energies ranging from 8.19 k J/tool to 18.98 k J/tool using the high resolution H-atom Rydberg tagging time-of-flight m... The crossed beams scattering dynamics of the F+HD→HF+D reaction have been studied at collision energies ranging from 8.19 k J/tool to 18.98 k J/tool using the high resolution H-atom Rydberg tagging time-of-flight method. Product rotational state-resolved differential cross sections have been measured. Most of the DF products are backward scattered at low collision energies and then gradually shift to the sideway as the collision energy increases. In addition to the backward and sideway scatterings, we have also observed the DF(v'=4) product in the forward direction for the first time for this reaction. The forward scattering DF(v=4) product also increases with the collision energy. Angular and collision energy dependence of the product energy disposals in different degrees of freedom have been determined. Collision energy dependence of the vibrational branching ratios has also been examined. Possible dynamical origins of the forward scattering DF(v'=4) products were discussed. 展开更多
关键词 F+HD→HF+D crossed molecular beam Rydberg tagging
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Crossed Beams Study on the Dynamics of F Atom Reaction with 1,2-Butadiene
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作者 肖得发 沈关林 +1 位作者 王秀岩 杨学明 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2010年第6期621-625,745,共6页
We have investigated the dynamics of the F+C4H6 reaction using the universal crossed molecular beam method. The C4H5F+H reaction channel was observed in this experiment. Angular resolved time-of-flight spectra have ... We have investigated the dynamics of the F+C4H6 reaction using the universal crossed molecular beam method. The C4H5F+H reaction channel was observed in this experiment. Angular resolved time-of-flight spectra have been measured for the C4H5F product. Prod- uct angular distributions as well as kinetic energy distributions were determined for this product channel. Experimental results show that the C4H5F product is largely backward scattered with considerable forward scattering signal, relative to the F atom beam direction. This suggests that the reaction channel mainly proceeds via a long-lived complex formation mechanism, with possible contribution from a direct SN2 type mechanism. 展开更多
关键词 Fluorine atom 1 2-Butadiene SN2 mechanism Universal crossed molecular beam
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Crossed Beams Study on the Dynamics of CI Atom Reaction with Silane
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作者 肖重发 沈关林 +1 位作者 王秀岩 杨学明 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2011年第1期4-7,I0003,共5页
The dynamics of the Cl+SiH4 reaction has been studied using the universal crossed molecular beam method. Angular resolved time-of-flight spectra have been measured for the channel SiH3Cl+H. Product angular distribut... The dynamics of the Cl+SiH4 reaction has been studied using the universal crossed molecular beam method. Angular resolved time-of-flight spectra have been measured for the channel SiH3Cl+H. Product angular distributions as well as energy distributions in the center-ofmass frame were determined for the channel. Experimental results show that the SiH3Cl product is mainly backward scattered relative to the Cl atom beam direction, suggesting that the channel takes place via a typical SN2 type reaction mechanism. 展开更多
关键词 Chlorine atom SILANE SN2 mechanism Universal crossed molecular beam
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High Resolution Crossed Molecular Beams Study on the F+HD→HF+D Reaction at Collision Energy of 5.43-18.73 kJ/mol
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作者 董文锐 肖春雷 +3 位作者 汪涛 戴东旭 王秀岩 杨学明 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2011年第5期507-514,I0003,共9页
The dynamics of F+HD→HF+D reaction has been studied at ten collision energies ranging from 5.43 kJ/mol to 18.73 kJ/mol using high-resolution H/D atom Rydberg tagging time-of-flight method. Product vibrational and r... The dynamics of F+HD→HF+D reaction has been studied at ten collision energies ranging from 5.43 kJ/mol to 18.73 kJ/mol using high-resolution H/D atom Rydberg tagging time-of-flight method. Product vibrational and rotational state-resolved differential cross sections have been determined. The intensity of the HF(v1=2) forward products decreases as the collision energy increases, suggesting that the resonance contribution is reduced as the collision energy increases. The forward peak of HF(vl=3) product has also been observed above the threshold of this product channel. Product energy disposals in different degrees of freedom have been analyzed. The collision energy dependence of the HF vibrational product branching was also determined. This work presents a comprehensive dynamic picture of this resonance mediated reaction in a wide collision energy regime, providing a good test ground for theoretical understandings of this interesting reaction at higher collision energies. 展开更多
关键词 F+HD→HF+D crossed molecular beam Rydberg tagging Reactive resonance
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Crossed Molecular Beam Study of H+CH4 and H+CD4 Reactions: Vibrationally Excited CH3/CD3 Product Channels
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作者 陈文韬 俞盛锐 +10 位作者 袁道福 谢婷 杨家岳 王思雯 罗畅 谭玉欣 缪月 张未卿 吴国荣 杨学明 王兴安 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2017年第6期609-613,I0001,共6页
We study the H+CH4/CD4-+H2/HD+CH3/CD3 reactions using the time sliced velocity map ion imaging technique. Ion images of the CH3/CD3 products were measured by the (2+1) resonance enhanced multi-photon ionization ... We study the H+CH4/CD4-+H2/HD+CH3/CD3 reactions using the time sliced velocity map ion imaging technique. Ion images of the CH3/CD3 products were measured by the (2+1) resonance enhanced multi-photon ionization (REMPI) detection method. Besides the CH3/CD3 products in the ground state, ion images of the vibrationally excited CH3/CD3 products were also observed at two collision energies of 0.72 and 1.06 eV. It is shown that the angular distribution of the products CH3/CD3 in vibrationally excited states gradually vary from backward scattering to sideways scattering as the collision energy increases. Compared to the CH3/CD3 products in the ground state, the CH3/CD3 products in vibrationally excited states tend to be more sideways scattered, indicating that larger impact parameters play a more important role in the vibrationally excited product channels. 展开更多
关键词 Velocity map ion imaging crossed molecular beam Angular distribution Vibrationally excited state
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Direct acceleration of electrons using two crossed Laguerre-Gaussian laser beams in vacuum
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作者 赵志国 吕百达 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第5期1022-1027,共6页
The basic physical characteristics of electrons accelerated by two linearly polarized and circularly symmetric crossed Laguerre-Gaussian (LG) laser beams with equal frequency and amplitude in vacuum are studied in d... The basic physical characteristics of electrons accelerated by two linearly polarized and circularly symmetric crossed Laguerre-Gaussian (LG) laser beams with equal frequency and amplitude in vacuum are studied in detail. The condition, under which electrons can be accelerated effectively, and the energy gain are discussed. 展开更多
关键词 electron acceleration crossed Laguerre-Gaussian (LG) beams slippage distance energy gain
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SHEAR STRESS ANALYSIS OF TIMOSHENKO'S BEAM WITH MULTIPLY CONNECTED CROSS SECTION
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作者 Li Zhaoxia Ko Janming Ni Yiqing 《Acta Mechanica Solida Sinica》 SCIE EI 2001年第1期48-57,共10页
In this paper, a finite element method is developed to numericallyevaluate the shear coefficient of Timoshenko's beam with multiplyconnected cross section. With focus on analyzing shear stressesdistributed at the ... In this paper, a finite element method is developed to numericallyevaluate the shear coefficient of Timoshenko's beam with multiplyconnected cross section. With focus on analyzing shear stressesdistributed at the neutral axis of the beam, an improved definitionof the shear coeffi- cient is presented. Based on this definition, aGalerkin-type finite element formulation is proposed to analyze theshear stresses and shear deflections. Numerical solutions of theexamples for some typical cross-sections are compared with thetheoretical results. The shear coefficient of tower sections of theTsing Ma Bridge is calculated by use of the proposed approach, sothat the finite element modeling of The bridge can be developed withthe accurate values of the sectional properties. 展开更多
关键词 Timoshenko's beam multiply connected cross section shear coefficient ELASTICITY
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Electron acceleration by two crossed Bessel-Gaussian beams in vacuum
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作者 赵志国 吕百达 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第10期2332-2337,共6页
The direct acceleration of electrons by using two linearly polarized crossed Bessel-Gaussian (BG) beams with equal frequency and amplitude in vacuum is proposed and studied. It is shown that two linearly polarized B... The direct acceleration of electrons by using two linearly polarized crossed Bessel-Gaussian (BG) beams with equal frequency and amplitude in vacuum is proposed and studied. It is shown that two linearly polarized BG beams of the same order (0 or 1) with a π-rad phase difference have a resultant non-zero longitudinal electric field on the z-axis and can be used, in principle, to accelerate electrons. 展开更多
关键词 laser electron acceleration crossed Bessel-Gaussian (BG) beams phase difference
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THE GENERAL SOLUTION FOR DYNAMIC RESPONSE OF NONHOMOGENEOUS BEAM WITH VARIABLECROSSSECTION
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作者 纪振义 叶开沅 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1994年第5期405-412,共8页
In this paper by means of the exact analytic method [1], the general solution fordynamic response of nonhomogeneous beam with variable cross section is obtained un-der arbitrary resonant load and boundary conditions. ... In this paper by means of the exact analytic method [1], the general solution fordynamic response of nonhomogeneous beam with variable cross section is obtained un-der arbitrary resonant load and boundary conditions. The problem is reduced to solvea non-positive differential equation. Generally, it is not solved by variational method.By the present method, the general solution for this problem may be written as an ana-lytic form. Hence, it is convenient for structure optimizing problem. In this paper, itsconvergence is proved. Numerical examples are given at the end of the paper. which in-dicates satisfactory results can be obtained. 展开更多
关键词 variable cross section beam dynamic response exact analyticmethod steady-state resonant vibration
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Modeling and analysis of piezoelectric beam with periodically variable cross-sections for vibration energy harvesting 被引量:7
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作者 M.HAJHOSSEINI M.RAFEEYAN 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2016年第8期1053-1066,共14页
A bimorph piezoelectric beam with periodically variable cross-sections is used for the vibration energy harvesting. The effects of two geometrical parameters on the first band gap of this periodic beam are investigate... A bimorph piezoelectric beam with periodically variable cross-sections is used for the vibration energy harvesting. The effects of two geometrical parameters on the first band gap of this periodic beam are investigated by the generalized differential quadrature rule (GDQR) method. The GDQR method is also used to calculate the forced vibration response of the beam and voltage of each piezoelectric layer when the beam is subject to a sinusoidal base excitation. Results obtained from the analytical method are compared with those obtained from the finite element simulation with ANSYS, and good agreement is found. The voltage output of this periodic beam over its first band gap is calculated and compared with the voltage output of the uniform piezoelectric beam. It is concluded that this periodic beam has three advantages over the uniform piezoelectric beam, i.e., generating more voltage outputs over a wide frequency range, absorbing vibration, and being less weight. 展开更多
关键词 vibration energy harvesting piezoelectric cantilever beam periodically variable cross-section vibration band gap forced vibration analysis generalized differential quadrature rule (GDQR)
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High Resolution Crossed Molecular Beams Study of the H+HD→H2+D Reaction
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作者 Ji-wei Sang Dao-fu Yuan +6 位作者 Wen-tao Chen Sheng-rui Yu Chang Luo Si-wen Wang Tao Wang Xue-ming Yang Xing-an Wang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2019年第1期123-128,I0003,共7页
The H+H2 reaction is the simplest chemical reaction system and has long been the prototype model in the study of reaction dynamics. Here we report a high resolution experimental investigation of the state-to-state rea... The H+H2 reaction is the simplest chemical reaction system and has long been the prototype model in the study of reaction dynamics. Here we report a high resolution experimental investigation of the state-to-state reaction dynamics in the H+HD→H2+D reaction by using the crossed molecular beams method and velocity map ion imaging technique at the collision energy of 1.17 eV. D atom products in this reaction were probed by the near threshold 1+1'(vacuum ultraviolet+ultraviolet) laser ionization scheme. The ion image with both high angular and energy resolution were acquired. State-to-state differential cross sections was accurately derived. Fast forward scattering oscillations, relating with interference effects in the scattering process, were clearly observed for H2 products at H2(v'=0,j'=1) and H2(v'=0,j'=3) rovibrational levels. This study further demonstrates the importance of measuring high-resolution differential cross sections in the study of state-to-state reaction dynamics in the gas phase. 展开更多
关键词 crossed molecular beams Velocity map ion imaging Threshold ionization Forward scattering oscillations High resolution Differential cross sections
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A crossed focused vortex beam with application to cold molecules
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作者 Meng Xia Yaling Yin +6 位作者 Chunying Pei Yuer Ye Ruoxi Gu Kang Yan Di Wu Yong Xia Jianping Yin 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第11期331-337,共7页
We report the generation of a crossed,focused,optical vortex beam by using a pair of hybrid holograms,which combine the vortex phase and lens phase onto a spatial light modulator.We study the intensity distributions o... We report the generation of a crossed,focused,optical vortex beam by using a pair of hybrid holograms,which combine the vortex phase and lens phase onto a spatial light modulator.We study the intensity distributions of the vortex beam in free propagation space,and the relationship of its dark spot size with the incident Gaussian beam’s waist,the lens’s focal length,and its orbital angular momentum.Our results show that the crossed,focused,vortex beam’s dark spot size can be as small as 16.3μm and adjustable by the quantum number of the orbital angular momentum,and can be used to increase the density of trapped molecules.Furthermore,we calculate the optical potential of the blue-detuned,crossed vortex beam for MgF molecules.It is applicable to cool and trap neutral molecules by intensity-gradient-induced Sisyphus cooling,as the intensity gradient of such vortex beam is extremely high near the focal point. 展开更多
关键词 cold molecule crossed focused vortex beam propagation characteristics optical potential
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Crossed Beam Experiment on the Validity of Born-Oppenheimer Approximation in Cl(2P)+D2→DCl+D Reaction
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作者 Yu-run Xie Yu-feng Wang +4 位作者 Wei Wang Tao Wang Dong-xu Dai Chun-lei Xiao Xue-ming Yang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2020年第2期135-138,I0002,共5页
The reaction of chlorine atom Cl(2P)(Cl(2P3/2)and Cl^*(2P1/2))with D2 was investigated at collision energy from 4.5 kcal/mol to 6.5 kcal/mol with a high-resolution crossed molecular beam apparatus using the technique ... The reaction of chlorine atom Cl(2P)(Cl(2P3/2)and Cl^*(2P1/2))with D2 was investigated at collision energy from 4.5 kcal/mol to 6.5 kcal/mol with a high-resolution crossed molecular beam apparatus using the technique of D-atom Rydberg tagging detection.The contribution from the spin-orbit excited reaction Cl^*(2P1/2)+D2,which is prohibited by Born-Oppenheimer(BO)approximation,was observed.Collision-energy dependence of differential cross sections(DCSs)near the backward scattering direction was measured.The BOforbidden reaction Cl^*+D2 was found to be dominant at lower collision energy.As collision energy increases,reactivity of BO-allowed reaction Cl+D2 increases much faster than that of BO-forbidden reaction and becomes dominant at higher collision energy.Our experiment indicates that the additional energy of spin-orbit excitation in Cl^*facilitates BO-forbidden reaction to pass through the barrier at lower collision energy,while BO approximation is still valid at collision energy near and above the reaction barrier.This tendency of reactivity of Cl/Cl^*+D2 is similar to the isotopic reaction of Cl/Cl^*+H2. 展开更多
关键词 Spin-orbit state Born-Oppenheimer approximation crossed beam experiment
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Crossed Beam Study on the F+D2→DF+D Reaction at Hyperthermal Collision Energy of 23.84 kJ/mol
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作者 Hei-long Wang Shu Su +4 位作者 Sheng-rui Yu Li Che Guo-rong Wu Kai-jun Yuan Xue-ming Yang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2019年第1期151-156,I0003,共7页
We presented an experimental apparatus combining the H-atom Rydberg tagging time-of-flight technique and the laser detonation source for studying crossed beam reactions at hyperthermal collision energies. The prelimin... We presented an experimental apparatus combining the H-atom Rydberg tagging time-of-flight technique and the laser detonation source for studying crossed beam reactions at hyperthermal collision energies. The preliminary study of the F+D2→DF+D reaction at hyperthermal collision energy of 23.84 kJ/mol was performed. Two beam sources were used in this study: one is the hyperthermal F beam source produced by a laser detonation process, and the other is D2 beam source generated by liquid-N2 cooled pulsed valve. Vibrational state-resolved di erential cross sections (DCSs) of product for the title reaction were determined. From the product vibrational state-resolved DCS, it can be concluded that products DF(v'=0, 1, 2, 3) are predominantly distributed in the sideway and backward scattering directions at this collision energy. However, the highest vibrational excited product DF(v'=4), is clearly peaked in the forward direction. The probable dynamical origins for these forward scattering products were analyzed and discussed. 展开更多
关键词 crossed molecular beam Hyperthermal collision energy Rydberg tagging laser detonation
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High Resolution Crossed Beams Scattering Study of the F+HD→DF+H Reaction
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作者 Xing-an Wang Li Che +4 位作者 Ze-feng Ren Ming-hui Qiu Dong-xu Dai Xiu-yan Wang Xue-ming Yang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2009年第6期551-555,J0001,共6页
Crossed beams scattering study was carried out on the F+HD→DF+H reaction using high- resolution H-atom Rydberg tagging time-of-flight technique. Vibrational state-resolved differential cross sections were measured,... Crossed beams scattering study was carried out on the F+HD→DF+H reaction using high- resolution H-atom Rydberg tagging time-of-flight technique. Vibrational state-resolved differential cross sections were measured, with partial rotational state resolution, at eight collision energies in the range of 2.51-5.60 kJ/mol. Experimental results indicated that the product angular distributions are predominantly backward scattered. As the collision energy increases, the backward scattered peak becomes broader gradually. Dependence of product vibration branching ratios on the collision energy was also determined. The experimental results show that the DF products are highly inverted in the vibrational state distribution and the DF (v'=3) product is the most populated state. Furthermore, the DF (v'=l) product has also been observed at collision energy above 3.97 kJ/mol. 展开更多
关键词 F+HD→DF+H crossed beam Rydberg tagging Backward scattering
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Crossed Molecular Beams and Theoretical Studies of the O(~3P)+1,2-Butadiene Reaction:Dominant Formation of Propene+CO and Ethylidene+Ketene Molecular Channels
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作者 Adriana Caracciolo Gianmarco Vanuzzo +4 位作者 Nadia Balucani Domenico Stranges Silvia Tanteri Carlo Cavallotti Piergiorgio Casavecchia 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2019年第1期113-122,I0002,共11页
Detailed understanding of the mechanism of the combustion relevant multichannel reactions of O(3P) with unsaturated hydrocarbons (UHs) requires the identification of all primary reaction products, the determination of... Detailed understanding of the mechanism of the combustion relevant multichannel reactions of O(3P) with unsaturated hydrocarbons (UHs) requires the identification of all primary reaction products, the determination of their branching ratios and assessment of intersystem crossing (ISC) between triplet and singlet potential energy surfaces (PESs). This can be best achieved combining crossed-molecular-beam (CMB) experiments with universal, soft ionization, mass-spectrometric detection and time-of-flight analysis to high-level ab initio electronic structure calculations of triplet/singlet PESs and RRKM/Master Equation computations of branching ratios (BRs) including ISC. This approach has been recently demonstrated to be successful for O(3P) reactions with the simplest UHs (alkynes, alkenes, dienes) containing two or three carbon atoms. Here, we extend the combined CMB/theoretical approach to the next member in the diene series containing four C atoms, namely 1,2-butadiene (methylallene) to explore how product distributions, branching ratios and ISC vary with increasing molecular complexity going from O(3P))+propadiene to O(3P)+1,2-butadiene. In particular, we focus on the most important, dominant molecular channels, those forming propene+CO (with branching ratio ∽0.5) and ethylidene+ketene (with branching ratio ∽0.15), that lead to chain termination, to be contrasted to radical forming channels (branching ratio ∽0.35) which lead to chain propagation in combustion systems. 展开更多
关键词 Reactive scattering crossed molecular beams O(3P) reaction dynamics O(3P)+diene reactions Soft electron ionization Intersystem crossing Ab initio quantum chemistry
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Digital Cross-Correlation Detection of Multi-Laser Beams Measuring System for Wind Field Detection
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作者 Li-Min Zhou Ya-Dong Jiang +1 位作者 Zheng-Yu Zhang Xiao-Lin Sui 《Journal of Electronic Science and Technology》 CAS 2010年第4期366-371,共6页
A cross-correlation detection method to process backscatter signals of multi-laser beams measuring (MLBM) is presented, which can be firstly filtered by the digital filter composed of average median filter and finit... A cross-correlation detection method to process backscatter signals of multi-laser beams measuring (MLBM) is presented, which can be firstly filtered by the digital filter composed of average median filter and finite impulse response (FIR) digital filter. The processing of backscatter signals using single-pulse and three-pulse cross-correlation detection methods is depicted in detail. From calculation results, the multi-pulse cross-correlation detection could effectively improve signal-to-noise ratio (SNR). Finally, both wind velocity and direction are determined by the peak-delay method based on the correlation function which shows high measuring precision and high SNR of the MLBM system with the assistance of the digital cross- correlation detection. 展开更多
关键词 cross-correlation detection digital filter multi-laser beams measuring system signal processing signal to noise ratio.
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类氦C离子诱发不同金属厚靶原子的K-X射线
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作者 梅策香 张小安 +6 位作者 周贤明 梁昌慧 曾利霞 张艳宁 杜树斌 郭义盼 杨治虎 《物理学报》 SCIE EI CAS CSCD 北大核心 2024年第4期136-143,共8页
利用中国原子能科学研究院HI-13MV串列加速器上提供的动能为15—55 MeV的类氦C离子分别轰击Fe,Ni,Nb和Mo金属厚靶,采用HpGe探测器测量了K-X射线,获得了相应的K-X射线的发射截面.本文中由于各个靶原子外壳层电离度的不同,类氦C离子与Fe,N... 利用中国原子能科学研究院HI-13MV串列加速器上提供的动能为15—55 MeV的类氦C离子分别轰击Fe,Ni,Nb和Mo金属厚靶,采用HpGe探测器测量了K-X射线,获得了相应的K-X射线的发射截面.本文中由于各个靶原子外壳层电离度的不同,类氦C离子与Fe,Ni靶原子相互作用发射的K_(β)与K_(α)X射线的分支强度比随入射离子动能增加而减小,而Nb,Mo靶原子发射的K-X射线分支强度比变化不明显.利用厚靶截面公式计算了靶原子K-X射线的发射截面,并与不同的理论模型及质子的结果进行了对比.结果表明随类氦C离子动能的增大,Fe,Ni靶原子发射的K_(β)与K_(α)X射线的总产生截面与考虑多电离的两体碰撞近似修正模型最为符合Nb,Mo靶原子发射的K_(β)与K_(α)X射线的总产生截面与平面波恩近似模型的理论值最为接近.质子与单核子C离子能量相同时,质子比类氦C离子激发不同靶的K-X射线产生截面约小3个数量级. 展开更多
关键词 X射线 粒子束 截面 两体碰撞近似 平面波恩近似
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跨课程自循环工程实训模式的构建与实践——以钢筋混凝土单梁实验为例
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作者 路韡 武红娟 +2 位作者 苗强强 顾皓玮 黄洪猛 《实验室研究与探索》 CAS 北大核心 2024年第9期177-181,共5页
以钢筋混凝土单梁试件为聚焦点,对工程实训课程进行了建设。实训中以项目制布置实训任务,围绕单梁准备、单梁制作、单梁实验、能力拓展、成绩评定等环节进行设计和建设,要求大四学生跨课程应用所学专业知识撰写项目方案,制作、检测、验... 以钢筋混凝土单梁试件为聚焦点,对工程实训课程进行了建设。实训中以项目制布置实训任务,围绕单梁准备、单梁制作、单梁实验、能力拓展、成绩评定等环节进行设计和建设,要求大四学生跨课程应用所学专业知识撰写项目方案,制作、检测、验收混凝土单梁,协助教师指导大二学生完成单梁破坏实验。实践证明,该实训模式串联了多门专业课程,使专业知识在实训课程中完成了循环;制作的单梁试件实现了专业内的自循环,节省了实验成本;学生实践能力、团队意识得到了锻炼,对工程流程和施工环境有了切身的体会。 展开更多
关键词 工程实训 课程建设 单梁破坏实验 跨课程
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