In the electron or x-ray scattering experiment,the measured spectra at larger momentum transfer are dominated by the electric dipole-forbidden transitions,while the corresponding selection rules for triatomic molecule...In the electron or x-ray scattering experiment,the measured spectra at larger momentum transfer are dominated by the electric dipole-forbidden transitions,while the corresponding selection rules for triatomic molecules have not been clearly elucidated.In this work,based on the molecular point group,the selection rules for the electric multipolarities of the electronic transitions of triatomic molecules are derived and summarized into several tables with the variation of molecular geometry in the transition process being considered.Based on the summarized selection rules,the electron energy loss spectra of H2O,CO2,and N2O are identified,and the momentum transfer dependence behaviors of their valence-shell excitations are explained.展开更多
Spin dependent selection rules for photonic transitions in hydrogen-like atoms is derived by using the solution of Dirac equation for hydrogen-like atoms. It is shown that photonic transitions occur when [ Δj=0,±...Spin dependent selection rules for photonic transitions in hydrogen-like atoms is derived by using the solution of Dirac equation for hydrogen-like atoms. It is shown that photonic transitions occur when [ Δj=0,±1,±2, while Δmj=0,±1,±2 ]. By applying the spin dependent selection rules, we can explain the observed (6s→7s) transition in Cesium (Cs) atom.展开更多
为准确模拟桥址随机车流荷载,提出基于可变元胞与跟驰理论的元胞自动机(cellular automata,CA)模型。首先,重新定义元胞构成,提出以车辆为核心的动态可变元胞,并将精确的轴间距和轴重信息融入车辆元胞,实现车辆荷载的精确模拟;然后,引...为准确模拟桥址随机车流荷载,提出基于可变元胞与跟驰理论的元胞自动机(cellular automata,CA)模型。首先,重新定义元胞构成,提出以车辆为核心的动态可变元胞,并将精确的轴间距和轴重信息融入车辆元胞,实现车辆荷载的精确模拟;然后,引入跟驰理论,提出基于跟驰理论的状态演化规则,推导每辆车的专有加速度,实现车辆微观交互的模拟;最后,提出基于实测动态称重系统(weigh in motion,WIM)数据的发车规则,依据WIM数据,重构任意时段的实际车队,并建立基于车头时距的发车规则,重现车辆通过WIM时的运动状态。基于所提出的发车规则和动态演化规则,实现车辆从进入道路到驶离道路全过程时空位置的准确模拟,结合融入精确轴载的车辆元胞,实现随机车流荷载的模拟。基于实测WIM数据验证所提模型的可行性和先进性。结果表明:可变元胞可以精确模拟车辆荷载;提出的状态演化规则可以根据不同车辆的运动状态计算得到每辆车的专属加速度,准确模拟每辆车在自由行驶和跟驰行驶时的不同运动状态;新发车规则可以重构任意时段的实测车队,结合新状态演化规则,可以实现桥址任意时段随机车流的模拟。结合精细化车辆荷载模拟和合理的车流模拟,可实现桥址随机车流荷载模拟。展开更多
In this paper, two cellular automata traffic models are proposed to simulate the operation of an expressway. The results show that the flow rate and the average velocity are generally equal in the same density which i...In this paper, two cellular automata traffic models are proposed to simulate the operation of an expressway. The results show that the flow rate and the average velocity are generally equal in the same density which is different among the lanes. The analysis of lane changing times and the velocity total deviation show some characteristics which are difficult to explain phase transitions under fundamental diagram theory. Therefore,the concept of lane changing probability is introduced, and it is concluded that the speed-limit rule can reduce the motivation of lane changing effectively.展开更多
-The ISO standard 14577 is challenged for its violation of the energy law, its wrong relation of normal force FN with impression depth h, and for its iterative treatments. The solution of this dilemma is the use of sa...-The ISO standard 14577 is challenged for its violation of the energy law, its wrong relation of normal force FN with impression depth h, and for its iterative treatments. The solution of this dilemma is the use of sacrosanct simplest calculation rules for the loading parabola (now FN = kh3/2) giving straight lines for cones, pyramids and wedges. They provide the physical penetration resistance hardness k with dimension [Nm-3/2] and allow for non-iterative calculations with closed formulas, using simple undeniable calculation rules. The physically correct FN versus h3/2 plot is universally valid. It separates out the most common surface effects and reveals gradients. It provides unmatched precision, including reliability checks of experimental data. Regression analysis of FN versus h3/2 plots reveals eventual unsteadiness kink phase-transition onset with the transition-energy. This is shown for all kinds of solid materials, including salts, silicon, organics, polymers, composites, and superalloys. Exothermic and endothermic single and consecutive multiple phase-transitions with their surface dependence are distinguished and the results compared in 5 Tables. The sharp phase-transition onsets and the transition energies provide unprecedented most important materials’ characteristics that are indispensable for safety reasons. ISO ASTM is thus urged to thoroughly revise ISO 14577 and to work out new standards for the mechanically (also thermally) stressed materials. For example, the constancy of the first phase-transition parameters must be controlled, and materials must only be admitted for maximal forces well below the first phase-transition onset. Such onset loads can now be easily calculated. The nevertheless repeated oppositions against the physical analysis of indentations rest on incredibly poor knowledge of basic mathematics, errors that are uncovered. The safety aspects caused by the present unphysical materials’ parameters are discussed.展开更多
This paper shows that exact calculation for transition probability can make some systems deviate fromFermi golden rule seriously. This paper also shows that the corresponding exact calculation of hopping rate inducedb...This paper shows that exact calculation for transition probability can make some systems deviate fromFermi golden rule seriously. This paper also shows that the corresponding exact calculation of hopping rate inducedby phonons for deuteron in Pd-D system with the many-body electron screening, proposed by Ichimaru, can explainthe experimental fact observed in Pd-D system, and predicts that perfection and low-dimension of Pd lattice are veryimportant for the phonon-induced hopping rate enhancement in Pd-D system.展开更多
Binuclear transition metal carbonyl clusters serve as the simplest models in understand- ing metal-metal and ligand bonding that are important organometallic chemistry catalysis. Binuclear first row transition metal c...Binuclear transition metal carbonyl clusters serve as the simplest models in understand- ing metal-metal and ligand bonding that are important organometallic chemistry catalysis. Binuclear first row transition metal carbonyl ions are produced via a pulsed laser vaporiza- tion/supersonic expansion cluster ion source in the gas phase. These ions are studied by mass-selected infrared photodissociation spectroscopy in the carbonyl stretching frequency region. Density functional theory calculations have been performed on the geometric struc- tures and vibrational spectra of the carbonyl ions. Their geometric and electronic structures are determined by comparison of the experimental IR spectra with the simulated spectra. The structure and the metM-metal and metal-CO bonding of both saturated and unsaturated homonuclear as well as heteronuclear carbonyl cluster cations and anions are discussed.展开更多
The paper presents a non-probabilistic approach to the time interval associated with the energy emission produced by the electron transition in a quantum system. The calculations were performed for the hydrogen atom a...The paper presents a non-probabilistic approach to the time interval associated with the energy emission produced by the electron transition in a quantum system. The calculations were performed for the hydrogen atom and the electron particle in a one-dimensional potential box. In both cases, the rule of conservation of the electron momentum has been applied. The results, limited to the time intervals of transitions between two neighbouring quantum energy levels, occur to be much similar to those obtained earlier with the aid of the Joule-Lenz energy emission theory.展开更多
为探明导致城市轨道交通运营事故发生的风险链式传导机理,构建事故风险链,提出FTA-Apriori(Fault Tree Analysis-Apriori)风险链构建方法。首先,针对城市轨道交通运营中风险灾害度高但支持度低的特点对Apriori算法进行改进,并通过灾害...为探明导致城市轨道交通运营事故发生的风险链式传导机理,构建事故风险链,提出FTA-Apriori(Fault Tree Analysis-Apriori)风险链构建方法。首先,针对城市轨道交通运营中风险灾害度高但支持度低的特点对Apriori算法进行改进,并通过灾害度与支持度二维耦合挖掘风险间的强关联规则;其次,通过FTA方法构建风险事故树,挖掘导致事故发生的风险组合,进而与强关联规则结合构建风险链。研究结果可为城市轨道交通运营风险链的构建提供一种全新的方法,进而揭示导致事故发生的风险链式传播机理,为风险链断链位置及风险精细化管控提供理论指导。展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0402300)the National Natural Science Foundation of China(Grant No.U1732133)the Science Fund from Chinese Academy of Sciences(Grant No.11320101003)
文摘In the electron or x-ray scattering experiment,the measured spectra at larger momentum transfer are dominated by the electric dipole-forbidden transitions,while the corresponding selection rules for triatomic molecules have not been clearly elucidated.In this work,based on the molecular point group,the selection rules for the electric multipolarities of the electronic transitions of triatomic molecules are derived and summarized into several tables with the variation of molecular geometry in the transition process being considered.Based on the summarized selection rules,the electron energy loss spectra of H2O,CO2,and N2O are identified,and the momentum transfer dependence behaviors of their valence-shell excitations are explained.
文摘Spin dependent selection rules for photonic transitions in hydrogen-like atoms is derived by using the solution of Dirac equation for hydrogen-like atoms. It is shown that photonic transitions occur when [ Δj=0,±1,±2, while Δmj=0,±1,±2 ]. By applying the spin dependent selection rules, we can explain the observed (6s→7s) transition in Cesium (Cs) atom.
基金Acknowledgements： This work is supported by the Natural Science Foundation of Henan （No.0211021600, No.0324220079） and the Fundamental Researches of Henan （No.004061800）
文摘为准确模拟桥址随机车流荷载,提出基于可变元胞与跟驰理论的元胞自动机(cellular automata,CA)模型。首先,重新定义元胞构成,提出以车辆为核心的动态可变元胞,并将精确的轴间距和轴重信息融入车辆元胞,实现车辆荷载的精确模拟;然后,引入跟驰理论,提出基于跟驰理论的状态演化规则,推导每辆车的专有加速度,实现车辆微观交互的模拟;最后,提出基于实测动态称重系统(weigh in motion,WIM)数据的发车规则,依据WIM数据,重构任意时段的实际车队,并建立基于车头时距的发车规则,重现车辆通过WIM时的运动状态。基于所提出的发车规则和动态演化规则,实现车辆从进入道路到驶离道路全过程时空位置的准确模拟,结合融入精确轴载的车辆元胞,实现随机车流荷载的模拟。基于实测WIM数据验证所提模型的可行性和先进性。结果表明:可变元胞可以精确模拟车辆荷载;提出的状态演化规则可以根据不同车辆的运动状态计算得到每辆车的专属加速度,准确模拟每辆车在自由行驶和跟驰行驶时的不同运动状态;新发车规则可以重构任意时段的实测车队,结合新状态演化规则,可以实现桥址任意时段随机车流的模拟。结合精细化车辆荷载模拟和合理的车流模拟,可实现桥址随机车流荷载模拟。
文摘In this paper, two cellular automata traffic models are proposed to simulate the operation of an expressway. The results show that the flow rate and the average velocity are generally equal in the same density which is different among the lanes. The analysis of lane changing times and the velocity total deviation show some characteristics which are difficult to explain phase transitions under fundamental diagram theory. Therefore,the concept of lane changing probability is introduced, and it is concluded that the speed-limit rule can reduce the motivation of lane changing effectively.
文摘-The ISO standard 14577 is challenged for its violation of the energy law, its wrong relation of normal force FN with impression depth h, and for its iterative treatments. The solution of this dilemma is the use of sacrosanct simplest calculation rules for the loading parabola (now FN = kh3/2) giving straight lines for cones, pyramids and wedges. They provide the physical penetration resistance hardness k with dimension [Nm-3/2] and allow for non-iterative calculations with closed formulas, using simple undeniable calculation rules. The physically correct FN versus h3/2 plot is universally valid. It separates out the most common surface effects and reveals gradients. It provides unmatched precision, including reliability checks of experimental data. Regression analysis of FN versus h3/2 plots reveals eventual unsteadiness kink phase-transition onset with the transition-energy. This is shown for all kinds of solid materials, including salts, silicon, organics, polymers, composites, and superalloys. Exothermic and endothermic single and consecutive multiple phase-transitions with their surface dependence are distinguished and the results compared in 5 Tables. The sharp phase-transition onsets and the transition energies provide unprecedented most important materials’ characteristics that are indispensable for safety reasons. ISO ASTM is thus urged to thoroughly revise ISO 14577 and to work out new standards for the mechanically (also thermally) stressed materials. For example, the constancy of the first phase-transition parameters must be controlled, and materials must only be admitted for maximal forces well below the first phase-transition onset. Such onset loads can now be easily calculated. The nevertheless repeated oppositions against the physical analysis of indentations rest on incredibly poor knowledge of basic mathematics, errors that are uncovered. The safety aspects caused by the present unphysical materials’ parameters are discussed.
文摘This paper shows that exact calculation for transition probability can make some systems deviate fromFermi golden rule seriously. This paper also shows that the corresponding exact calculation of hopping rate inducedby phonons for deuteron in Pd-D system with the many-body electron screening, proposed by Ichimaru, can explainthe experimental fact observed in Pd-D system, and predicts that perfection and low-dimension of Pd lattice are veryimportant for the phonon-induced hopping rate enhancement in Pd-D system.
基金supported by the National Natural Science Foundation of China(No.21688102,No.21573047and No.21273045)
文摘Binuclear transition metal carbonyl clusters serve as the simplest models in understand- ing metal-metal and ligand bonding that are important organometallic chemistry catalysis. Binuclear first row transition metal carbonyl ions are produced via a pulsed laser vaporiza- tion/supersonic expansion cluster ion source in the gas phase. These ions are studied by mass-selected infrared photodissociation spectroscopy in the carbonyl stretching frequency region. Density functional theory calculations have been performed on the geometric struc- tures and vibrational spectra of the carbonyl ions. Their geometric and electronic structures are determined by comparison of the experimental IR spectra with the simulated spectra. The structure and the metM-metal and metal-CO bonding of both saturated and unsaturated homonuclear as well as heteronuclear carbonyl cluster cations and anions are discussed.
文摘The paper presents a non-probabilistic approach to the time interval associated with the energy emission produced by the electron transition in a quantum system. The calculations were performed for the hydrogen atom and the electron particle in a one-dimensional potential box. In both cases, the rule of conservation of the electron momentum has been applied. The results, limited to the time intervals of transitions between two neighbouring quantum energy levels, occur to be much similar to those obtained earlier with the aid of the Joule-Lenz energy emission theory.
文摘为探明导致城市轨道交通运营事故发生的风险链式传导机理,构建事故风险链,提出FTA-Apriori(Fault Tree Analysis-Apriori)风险链构建方法。首先,针对城市轨道交通运营中风险灾害度高但支持度低的特点对Apriori算法进行改进,并通过灾害度与支持度二维耦合挖掘风险间的强关联规则;其次,通过FTA方法构建风险事故树,挖掘导致事故发生的风险组合,进而与强关联规则结合构建风险链。研究结果可为城市轨道交通运营风险链的构建提供一种全新的方法,进而揭示导致事故发生的风险链式传播机理,为风险链断链位置及风险精细化管控提供理论指导。
