Vibrational strong coupling(VSC)provides a promising way towards not only enhanced control of infrared light but also reshaping of molecular properties,which opens up unprecedented opportunities in ultrasensitive infr...Vibrational strong coupling(VSC)provides a promising way towards not only enhanced control of infrared light but also reshaping of molecular properties,which opens up unprecedented opportunities in ultrasensitive infrared spectroscopy,modification of chemical reactions,and exploration of nonlinear quantum effects.Surface plasmon resonance,excited on simple plasmonic resonators in the infrared,has been demonstrated as a means to realize VSC,but suffers from either limited quality factor for realizing large Rabi splitting or poor reconfigurability for precise detuning control.Here we propose and experimentally demonstrate,for the first time,an on-chip plasmonic resonator based on degeneracy breaking of Wood’s anomaly for VSC.Leveraging the low damping rate of the surface state induced by this degeneracy breaking,we achieve a plasmonic resonance with a high-Q factor exceeding~110,resulting in a Rabi splitting up to~112 cm^(-1) with a subwavelength molecular layer.Additionally,the dispersion of the surface state allows for precise control over VSC detuning by simply adjusting the incident angle of excitation light,even in the absence of photons,enabling a broad detuning range up to 300 cm^(-1).These experimental results align well with our analytical model and numerical simulation.This work provides a promising integrated platform for VSC,with various potential applications in on-chip spectroscopy,polariton chemistry,and polariton devices.展开更多
Molecular dynamics(MD)is a powerful method widely used in materials science and solid-state physics.The accuracy of MD simulations depends on the quality of the interatomic potentials.In this work,a special class of e...Molecular dynamics(MD)is a powerful method widely used in materials science and solid-state physics.The accuracy of MD simulations depends on the quality of the interatomic potentials.In this work,a special class of exact solutions to the equations of motion of atoms in a body-centered cubic(bcc)lattice is analyzed.These solutions take the form of delocalized nonlinear vibrational modes(DNVMs)and can serve as an excellent test of the accuracy of the interatomic potentials used in MD modeling for bcc crystals.The accuracy of the potentials can be checked by comparing the frequency response of DNVMs calculated using this or that interatomic potential with that calculated using the more accurate ab initio approach.DNVMs can also be used to train new,more accurate machine learning potentials for bcc metals.To address the above issues,it is important to analyze the properties of DNVMs,which is the main goal of this work.Considering only the point symmetry groups of the bcc lattice,34 DNVMs are found.Since interatomic potentials are not used in finding DNVMs,they are exact solutions for any type of potential.Here,the simplest interatomic potentials with cubic anharmonicity are used to simplify the analysis and to obtain some analytical results.For example,the dispersion relations for small-amplitude phonon modes are derived,taking into account interactions between up to the fourth nearest neighbor.The frequency response of the DNVMs is calculated numerically,and for some DNVMs examples of analytical analysis are given.The energy stored by the interatomic bonds of different lengths is calculated,which is important for testing interatomic potentials.The pros and cons of using DNVMs to test and improve interatomic potentials for metals are discussed.Since DNVMs are the natural vibrational modes of bcc crystals,any reliable interatomic potential must reproduce their properties with reasonable accuracy.展开更多
Ammonium dinitramide(ADN),as a high-energy oxidizer widely applied in the field of rocket and missile propellants,has a prominent issue of high hygroscopicity due to its strong polarity.The previous coating encapsulat...Ammonium dinitramide(ADN),as a high-energy oxidizer widely applied in the field of rocket and missile propellants,has a prominent issue of high hygroscopicity due to its strong polarity.The previous coating encapsulation methods have struggled to address the problems of uneven coating and polarity mismatch.This research innovatively introduces perfluorooctanoic acid(PFOA)as a polar transition intermediate layer.Utilizing the polarity of one end of it to adsorb on the surface of ADN through hydrogen bonds,the problem of polarity mismatch is effectively overcome.Meanwhile,the vibrational magnetron sputtering process has been first applied in the energetic field,with a special vibrating abutment enhancing ADN particle fluidity to solve coating non-uniformity,thus preparing prilled ADN@PFOA@PTFE core-dual-shell composites.Performance tests reveal that this composite material possesses excellent hydrophobic and anti-hygroscopic properties.When left at 25℃and 75%RH for 3 days,moisture absorption was reduced by more than 90%compared to pure ADN.Simultaneously,its thermal stability,heat release performance,and combustion performance have been improved.The research achievements optimize the storage conditions of ADN in the application of rocket and missile propellants,providing solid support and broad development prospects for technological innovation in military fields.展开更多
Cryogenic ion traps offer substantial advantages over their room-temperature counterparts,particularly in terms of stable ion confinement and cooling.However,this technological advancement has introduced a significant...Cryogenic ion traps offer substantial advantages over their room-temperature counterparts,particularly in terms of stable ion confinement and cooling.However,this technological advancement has introduced a significant challenge,namely the generation of additional vibrational noise.This noise is pronounced during the compression and expansion phases of the Gifford–McMahon cycle refrigerator and stems from the mechanical operation of the cold head.The residual vibrational noise can modulate the Rabi oscillation frequency,thereby compromising the fidelity of the quantum logic gate.In this study,we quantitatively assess the impact of residual vibrational noise and introduce an innovative strategy for its mitigation.This strategy was designed to reduce superimposed potential fluctuations within a cryogenic surface electrode ion trap.The measured residual vibrational noise was used for real-time feedback control.Addressing the inverse determination of the compensating potential for a stable superimposed trapping potential is an inherently ill-posed problem considering known measurement noise results.By applying quadratic programming,we numerically calculated the optimal time series for the compensation potential.An ensemble of these compensation voltages was applied in real time to the static compensation electrodes.Although this method is in the theoretical stage,we believe that it can effectively suppress the translation induced by vibrational noise and foster the creation of a stable superimposed harmonic potential.The deployment of this technique is expected to substantially improve the accuracy of quantum operations,thereby fueling the evolution of quantum technologies.展开更多
This article presents the optical evaluation of the vibrational behavior of a steel bar,by a non-conventional optoacoustic procedure,the LPD(laser photo deflection)method.On this occasion the bar is located horizontal...This article presents the optical evaluation of the vibrational behavior of a steel bar,by a non-conventional optoacoustic procedure,the LPD(laser photo deflection)method.On this occasion the bar is located horizontal and fixed at both ends.Through our procedure we experimentally find the first 9 Eigen frequencies(21 Hz,60 Hz,116 Hz...)and correlate them using the cantilever theory.展开更多
Ethylene carbonate(EC)is an important electrolyte used in lithium-ion batteries due to its excellent electrochemical performance.However,propylene carbonate(PC)differs from EC by only one methyl substituent and exhibi...Ethylene carbonate(EC)is an important electrolyte used in lithium-ion batteries due to its excellent electrochemical performance.However,propylene carbonate(PC)differs from EC by only one methyl substituent and exhibits markedly poorproperties.The EC-PC disparity is still poorly understood at the molecular level.In this study,we demonstrated that femtosecond broadband sum frequency generation vibrational spectroscopy(SFG-VS)with simultaneous measurement of multiple polarization combinations provides a powerful probe for investigating the physicochemical processes at the electrode-electrolyte interface during the charge-discharge cycles of lithium batteries.Using monolayer graphene as the working electrode,we observed the distinct reaction outcomes of EC and PC on the electrode surface.The interfacial reaction of EC occurred only in the first charge-discharge cycle,while the interfacial reaction of PC was ongoing along with the charge-discharge cycles,which explains why EC is a better electrolyte choice than PC.This study provides direct experimental evidence in elucidating the differences in interfacial performance between EC and PC,facilitating a deeper understanding of battery interface reactions and guiding the design of high-performance lithium-ion batteries.展开更多
Evidence for metallization in dense oxygen has been reported for over 30 years[Desgreniers et al.,J.Phys.Chem.94,1117(1990)]at a now routinely accessible 95 GPa[Shimizu et al.,Nature 393,767(1998)].However,despite the...Evidence for metallization in dense oxygen has been reported for over 30 years[Desgreniers et al.,J.Phys.Chem.94,1117(1990)]at a now routinely accessible 95 GPa[Shimizu et al.,Nature 393,767(1998)].However,despite the longevity of this result and the technological advances since,the nature of the metallic phase remains poorly constrained[Akahama et al.,Phys.Rev.Lett.74,4690(1995);Goncharov et al.,Phys.Rev.B 68,224108(2003);Ma,Phys.Rev.B 76,064101(2007);and Weck et al.,Phys.Rev.Lett.102,255503(2009)].In this work,through Raman spectroscopy,we report the distinct vibrational characteristics of metallicζ-O_(2) from 85 to 225 GPa.In comparison with numerical simulations,wefind reasonable agreement with the candidate structure up to about 150 GPa.At higher pressures,the C2/mstructure is found to be unstable and incompatible with experimental observations.Alternative candidate structures,and Ci,with C2/m C2/conly two molecules in the primitive unit cell,are found to be stable and more compatible with measurements above 175 GPa,indicative of the dissociation of(O_(2))4 units.Further,we report and discuss a strong hysteresis and metastability with the precursory phaseϵ-O_(2).Thesefindings will reinvigorate experimental and theoretical work into the dense oxygen system,which will have importance for oxygen-bearing chemistry,prevalent in the deep Earth,as well as fundamental physics.展开更多
This article presents a compact magnetic levitation energy harvester(MLEH)with tunable resonant frequency.Unlike many of the reported tunable harvesters with unknown tuning results,the proposed MLEH can be tuned towar...This article presents a compact magnetic levitation energy harvester(MLEH)with tunable resonant frequency.Unlike many of the reported tunable harvesters with unknown tuning results,the proposed MLEH can be tuned toward designated resonant frequency values within its tuning range.The targeted tuning processes is realized by a nonlinear magnet repulsive force exerted on a Halbach magnet array,combined with a calibrated scaling system.At a sinusoidal acceleration of±0.15 g,the maximum frequency tuning range of the proposed MLEH is 6.3 Hz(8.1–14.4 Hz),which is 77.8%of its resonant MLEH(8.1 Hz).At a frequency of 9.7 Hz,the output power is 462.1μW and the calculated normalized power density is 496μWcm^(−3)g^(−2).展开更多
We experimentally investigate the vibrational state distribution of the cations after carbon monoxide(CO)molecules are irradiated by strong laser fields.Vibrational-resolved fluorescent spectrum is observed,which can ...We experimentally investigate the vibrational state distribution of the cations after carbon monoxide(CO)molecules are irradiated by strong laser fields.Vibrational-resolved fluorescent spectrum is observed,which can be well assigned as the A^(2)Π(υ′=0-3)→X^(2)Σ+(υ″=0-3)transitions of the cations CO+,indicating the strong field ionization of the inner molecular orbital of CO.Relative distribution of vibrational states A^(2)Π(υ′=0-3)of CO+is retrieved from the measured spectrum and the Franck-Condon factors.It is found that the vibrational state distribution in strong field ionization of CO apparently deviates from the Franck-Condon-like distribution,but is in good agreement with the calculations,in which we include both the ionization rate and the overlapping between the vibrational wavefunctions of the neutral and cationic electronic states.The distribution of CO+(A^(2)Π,υ′)strongly depends on the laser intensity but is less dependent on the laser ellipticity.Analysis indicates the inter-nuclear distance-dependent ionization plays a significant role in the vibrational state distribution induced by strong field ionization of CO molecules.展开更多
Threshold photoelectron spectrum of CH_(2)F_(2)in the photon energy range of 12.45-14.10 eV was re-investigated by means of a combination of photo-electron-photoion coincidence experiments and density functional theor...Threshold photoelectron spectrum of CH_(2)F_(2)in the photon energy range of 12.45-14.10 eV was re-investigated by means of a combination of photo-electron-photoion coincidence experiments and density functional theory calculations.A series of vibrational peaks were distinctly observed in this range.Using optimized geometries and vibrational frequencies of the CH_(2)F_(2)neutral and its cation in ground state at the M06-2X/cc-pVTZ level of theory,Franck-Condon factor simulations were conducted.Taking into account anharmonicity influences,a perfect agreement between the simulated and experimental spectra has been achieved.From the reliable vibrational assignments,adiabatic and vertical ionization energies of CH_(2)F_(2)are derived as 12.371±0.010 eV and 13.281±0.010 eV,respectively.In addition,the experimental frequencies of four vibrational modes with ai symmetry for CH_(2)F_(2)+(X^(2)B_(1))ions are determined.展开更多
Transporting and storing hydrogen is a complex technological task.A typical problem relates to the need to minimize the strength of fluid motion and heat transfer near the walls of the container.In this work this prob...Transporting and storing hydrogen is a complex technological task.A typical problem relates to the need to minimize the strength of fluid motion and heat transfer near the walls of the container.In this work this problem is tackled numerically assuming an infinite cavity of pipe square cross-section,located in a constant external temperature gradient.In particular,a method based on the application of vibrations to suppress the gravitational convection mechanism is explored.A parametric investigation is conducted and the limits of applicability of the method for small Grashof numbers(10e4)are determined.It is shown that it is possible to minimize the intensity of the vibrogravitational flow for any values of the problem parameters if correction factors are specified.The results obtained can be applied in technological processes associated with the transportation,storage and use of hydrogen:pumping the working fluid through pipes,storage in tanks,as well as flow processes in the combustion chambers of power plants.展开更多
Important challenges must be addressed to make wind turbines sustainable renewable energy sources.A typical problem concerns the design of the foundation.If the pile diameter is larger than that of the jacket platform...Important challenges must be addressed to make wind turbines sustainable renewable energy sources.A typical problem concerns the design of the foundation.If the pile diameter is larger than that of the jacket platform,traditional mechanical models cannot be used.In this study,relying on the seabed soil data of an offshore wind farm,the m-method and the equivalent embedded method are used to address the single-pile wind turbine foundation problem for different pile diameters.An approach to determine the equivalent pile length is also proposed accordingly.The results provide evidence for the effectiveness and reliability of the model based on the equivalent embedded method.展开更多
The design of a ship is a process facilitated by different parallel departments.Specialists from various disciplines jointly work on a project,eventually covering the entire process.Though simultaneously,these discipl...The design of a ship is a process facilitated by different parallel departments.Specialists from various disciplines jointly work on a project,eventually covering the entire process.Though simultaneously,these disciplines are often subject to a hierarchy,either clearly defined or dictated by necessity.Within these branches,despite a growing interest in enhancing the comfort on board ships,noise and vibration design is among the most sacrificed.Compared to hydrodynamic or structural modifications,efforts devoted to improving vibrational comfort are generally slightly impactful and costly.Consequently,these improvements are often relegated to the final stages of the design procedure.The underestimation of noise and vibrational comfort design can generate serious,unexpected issues emerging only in the advanced phases of the ship’s life,and post-construction interventions are often needed.This case is exemplified in the current study,where the crew of the research vessel Mintis,a catamaran-type hull,reported discomfort in the navigation wheelhouse.A measurement campaign was set up to assess the complaints of the operating personnel regarding the high vibrational levels.Subsequent to the measurements,a numerical simulation,specifically comprising a modal analysis,was conducted to investigate the nature of the disturbance and distinguish the underlying mechanism at its origin.This paper meticulously presents and discusses the strategy undertaken to analyze and solve the vibrational problem encountered on board,with particular attention to the criteria and the modeling considerations adopted.展开更多
Decoupling the complicated vibrational-vibrational （V-V） coupling of a multimode vibrational relaxation remains a challenge for analyzing the sound relaxational absorption in multi-component gas mixtures. In our pre...Decoupling the complicated vibrational-vibrational （V-V） coupling of a multimode vibrational relaxation remains a challenge for analyzing the sound relaxational absorption in multi-component gas mixtures. In our previous work [Acta Phys. Sin. 61 174301 （2012）], an analytical model to predict the sound absorption from vibrational relaxation in a gas medium is proposed. In this paper, we develop the model to decouple the V-V coupled energy to each vibrationaltranslational deexcitation path, and analyze how the multimode relaxations form the peaks of sound absorption spectra in gas mixtures. We prove that a multimode relaxation is the sum of its decoupled single-relaxation processes, and only the decoupled process with a significant isochoric-molar-heat can be observed as an absorption peak. The decoupling model clarifies the essential processes behind the peaks in spectra arising from the multimode relaxations in multi-component gas mixtures. The simulation validates the proposed decoupling model.展开更多
Characterization of real-time and ultrafast motions of the complex molecules at surface and interface is critical to understand how interracial molecules function. It requires to develop surface-sensitive, fast-identi...Characterization of real-time and ultrafast motions of the complex molecules at surface and interface is critical to understand how interracial molecules function. It requires to develop surface-sensitive, fast-identification, and time-resolved techniques. In this study, we employ several key technical procedures and successfully develop a highly sensitive femtosecond time-resolved sum frequency generation vibrational spectroscopy （SFG-VS） system. This system is able to measure the spectra with two polarization combinations （ssp and ppp, or psp and ssp） simultaneously. It takes less than several seconds to collect one spectrum. To the best of our knowledge, it is the fastest speed of collecting SFG spectra reported by now. Using the time-resolved measurement, ultrafast vibrational dynamics of the N-H mode of α-helical peptide at water interface is determined. It is found that the membrane environment does not affect the N-H vibrational relaxation dynamics. It is expected that the time-resolved SFG system will play a vital role in the deep understanding of the dynamics and interaction of the complex molecules at surface and interface. Our method may also provide an important technical proposal for the people who plan to develop time-resolved SFG systems with simultaneous measurement of multiple polarization combinations.展开更多
Based on previous laser-induced fluorescence excitation spectroscopy work, the vibrational constants of neutral FeS in the X5 △ electronic state were obtained by directly mapping the ground-state vibrational levels u...Based on previous laser-induced fluorescence excitation spectroscopy work, the vibrational constants of neutral FeS in the X5 △ electronic state were obtained by directly mapping the ground-state vibrational levels up to v＂=3 using conventional laser-induced dispersed fluorescence spectroscopy. The vibrational frequency of FeS（X5 △） （518±5 cm-1） agrees well with that reported in a recent PES measurement （520±30 cm-1） [J. Phys. Chem. A 107, 2821 （2003）] which is the only one prior experimental vibrational frequency value for the 5 △ state of FeS. Careful comparisons of our experimental results and those documented in the literature （mainly from theoretical predictions） suggest that the ground state of FeS is 5 △ state.展开更多
An algebraic Harniltonian for the two coupled nonlinear vibrations of highly excited nonrigid molecule HCP was presented. The Hamiltonian reduces to the conventional one in a limit which was expressed in terms of harm...An algebraic Harniltonian for the two coupled nonlinear vibrations of highly excited nonrigid molecule HCP was presented. The Hamiltonian reduces to the conventional one in a limit which was expressed in terms of harmonic oscillator operators. It showed that the algebraic model can better reproduce the data than the conventional model by fitting the observed data of HCP.展开更多
The potential energy curves of the ground state X2∑＋g of the fluorine molecule have been accurately reconstructed employing the Ryderg-Klein-Rees （RKR） method extrapolated by a Hulburt and Hirschfeler potential fu...The potential energy curves of the ground state X2∑＋g of the fluorine molecule have been accurately reconstructed employing the Ryderg-Klein-Rees （RKR） method extrapolated by a Hulburt and Hirschfeler potential function for longer internuclear distances. Solving the corresponding radial one-dimensional Schr？dinger equation of nuclear motion yields 22 bound vibrational levels above v=0. The comparison of these theoretical levels with the experimental data yields a mean absolute deviation of about 7.6 cm^-1 over the 23 levels. The highest vibrational level energy obtained using this method is 13308.16 cm？1 and the relative deviation compared with the experimental datum of 13408.49 cm^-1 is only 0.74%. The value from our method is much closer and more accurate than the value obtained by the quantum mechanical ab initio method by Bytautas. The reported agreement of the vibrational levels and dissociation energy with experiment is contingent upon the potential energy curve of the F2 ground state.展开更多
In this paper, we have applied the Lie algebraic model to nano-bio molecules to determine the vibrational spectra of different stretching and bending vibrational modes. The determined vibrational energy levels by the ...In this paper, we have applied the Lie algebraic model to nano-bio molecules to determine the vibrational spectra of different stretching and bending vibrational modes. The determined vibrational energy levels by the Lie algebraic model are compared with the experimental data. The results from the theoretical mode[ are consistent with the experimental data. The vibrational energy levels are clustering in the excited states.展开更多
The vibrational wave function of the target theoretically plays an important role in the calculation of vibrational excitation cross sections. By a careful study of the differential cross sections resulting from diffe...The vibrational wave function of the target theoretically plays an important role in the calculation of vibrational excitation cross sections. By a careful study of the differential cross sections resulting from different vibrational wave functions we find that cross sections are susceptible to vibrational wave functions. Minor changes in the vibration wave lhnction may cause a significant change in the cross section. Even more surprising is that by selecting a few numbers of potential models （which determine the vibrational wave functions） we can often calculate the differential scattering cross section in much closer agreement with experiment in the framework of body-frame vibrational close-coupling theory, which suggest that an accurate potential energy may play a more important role in scattering than we thought betbre.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2024YFE0105200)the National Nature Science Foundation of China(Grant No.62405284)+2 种基金the Key Research and Development Program of Henan Province(Grant No.241111220600)the JSPS KAKENHI(Grant No.JP20K14785)the Murata Science Foundation.
文摘Vibrational strong coupling(VSC)provides a promising way towards not only enhanced control of infrared light but also reshaping of molecular properties,which opens up unprecedented opportunities in ultrasensitive infrared spectroscopy,modification of chemical reactions,and exploration of nonlinear quantum effects.Surface plasmon resonance,excited on simple plasmonic resonators in the infrared,has been demonstrated as a means to realize VSC,but suffers from either limited quality factor for realizing large Rabi splitting or poor reconfigurability for precise detuning control.Here we propose and experimentally demonstrate,for the first time,an on-chip plasmonic resonator based on degeneracy breaking of Wood’s anomaly for VSC.Leveraging the low damping rate of the surface state induced by this degeneracy breaking,we achieve a plasmonic resonance with a high-Q factor exceeding~110,resulting in a Rabi splitting up to~112 cm^(-1) with a subwavelength molecular layer.Additionally,the dispersion of the surface state allows for precise control over VSC detuning by simply adjusting the incident angle of excitation light,even in the absence of photons,enabling a broad detuning range up to 300 cm^(-1).These experimental results align well with our analytical model and numerical simulation.This work provides a promising integrated platform for VSC,with various potential applications in on-chip spectroscopy,polariton chemistry,and polariton devices.
基金support of the RSF Grant No.24-11-00139(analytics,numerical results,manuscript writing)Daxing Xiong acknowledges the support of the NNSF Grant No.12275116,the NSF Grant No.2021J02051,and the startup fund Grant No.MJY21035For Aleksey A.Kudreyko,this work was supported by the Bashkir StateMedicalUniversity StrategicAcademic Leadership Program(PRIORITY-2030)(analytics).
文摘Molecular dynamics(MD)is a powerful method widely used in materials science and solid-state physics.The accuracy of MD simulations depends on the quality of the interatomic potentials.In this work,a special class of exact solutions to the equations of motion of atoms in a body-centered cubic(bcc)lattice is analyzed.These solutions take the form of delocalized nonlinear vibrational modes(DNVMs)and can serve as an excellent test of the accuracy of the interatomic potentials used in MD modeling for bcc crystals.The accuracy of the potentials can be checked by comparing the frequency response of DNVMs calculated using this or that interatomic potential with that calculated using the more accurate ab initio approach.DNVMs can also be used to train new,more accurate machine learning potentials for bcc metals.To address the above issues,it is important to analyze the properties of DNVMs,which is the main goal of this work.Considering only the point symmetry groups of the bcc lattice,34 DNVMs are found.Since interatomic potentials are not used in finding DNVMs,they are exact solutions for any type of potential.Here,the simplest interatomic potentials with cubic anharmonicity are used to simplify the analysis and to obtain some analytical results.For example,the dispersion relations for small-amplitude phonon modes are derived,taking into account interactions between up to the fourth nearest neighbor.The frequency response of the DNVMs is calculated numerically,and for some DNVMs examples of analytical analysis are given.The energy stored by the interatomic bonds of different lengths is calculated,which is important for testing interatomic potentials.The pros and cons of using DNVMs to test and improve interatomic potentials for metals are discussed.Since DNVMs are the natural vibrational modes of bcc crystals,any reliable interatomic potential must reproduce their properties with reasonable accuracy.
基金funded by Open Research Fund Program of National Key Laboratory of Aerospace Chemical Power(NKLACP120241B04)National Natural Science Foundation of China Youth Science Foundation(12402450)。
文摘Ammonium dinitramide(ADN),as a high-energy oxidizer widely applied in the field of rocket and missile propellants,has a prominent issue of high hygroscopicity due to its strong polarity.The previous coating encapsulation methods have struggled to address the problems of uneven coating and polarity mismatch.This research innovatively introduces perfluorooctanoic acid(PFOA)as a polar transition intermediate layer.Utilizing the polarity of one end of it to adsorb on the surface of ADN through hydrogen bonds,the problem of polarity mismatch is effectively overcome.Meanwhile,the vibrational magnetron sputtering process has been first applied in the energetic field,with a special vibrating abutment enhancing ADN particle fluidity to solve coating non-uniformity,thus preparing prilled ADN@PFOA@PTFE core-dual-shell composites.Performance tests reveal that this composite material possesses excellent hydrophobic and anti-hygroscopic properties.When left at 25℃and 75%RH for 3 days,moisture absorption was reduced by more than 90%compared to pure ADN.Simultaneously,its thermal stability,heat release performance,and combustion performance have been improved.The research achievements optimize the storage conditions of ADN in the application of rocket and missile propellants,providing solid support and broad development prospects for technological innovation in military fields.
基金supported by the National Natural Science Foundation of China(Grant Nos.12204543,12004430,12074433,12174447,and 12174448)。
文摘Cryogenic ion traps offer substantial advantages over their room-temperature counterparts,particularly in terms of stable ion confinement and cooling.However,this technological advancement has introduced a significant challenge,namely the generation of additional vibrational noise.This noise is pronounced during the compression and expansion phases of the Gifford–McMahon cycle refrigerator and stems from the mechanical operation of the cold head.The residual vibrational noise can modulate the Rabi oscillation frequency,thereby compromising the fidelity of the quantum logic gate.In this study,we quantitatively assess the impact of residual vibrational noise and introduce an innovative strategy for its mitigation.This strategy was designed to reduce superimposed potential fluctuations within a cryogenic surface electrode ion trap.The measured residual vibrational noise was used for real-time feedback control.Addressing the inverse determination of the compensating potential for a stable superimposed trapping potential is an inherently ill-posed problem considering known measurement noise results.By applying quadratic programming,we numerically calculated the optimal time series for the compensation potential.An ensemble of these compensation voltages was applied in real time to the static compensation electrodes.Although this method is in the theoretical stage,we believe that it can effectively suppress the translation induced by vibrational noise and foster the creation of a stable superimposed harmonic potential.The deployment of this technique is expected to substantially improve the accuracy of quantum operations,thereby fueling the evolution of quantum technologies.
文摘This article presents the optical evaluation of the vibrational behavior of a steel bar,by a non-conventional optoacoustic procedure,the LPD(laser photo deflection)method.On this occasion the bar is located horizontal and fixed at both ends.Through our procedure we experimentally find the first 9 Eigen frequencies(21 Hz,60 Hz,116 Hz...)and correlate them using the cantilever theory.
基金supported by the National Natural Science Foundation of China(No.21925302)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0450202).
文摘Ethylene carbonate(EC)is an important electrolyte used in lithium-ion batteries due to its excellent electrochemical performance.However,propylene carbonate(PC)differs from EC by only one methyl substituent and exhibits markedly poorproperties.The EC-PC disparity is still poorly understood at the molecular level.In this study,we demonstrated that femtosecond broadband sum frequency generation vibrational spectroscopy(SFG-VS)with simultaneous measurement of multiple polarization combinations provides a powerful probe for investigating the physicochemical processes at the electrode-electrolyte interface during the charge-discharge cycles of lithium batteries.Using monolayer graphene as the working electrode,we observed the distinct reaction outcomes of EC and PC on the electrode surface.The interfacial reaction of EC occurred only in the first charge-discharge cycle,while the interfacial reaction of PC was ongoing along with the charge-discharge cycles,which explains why EC is a better electrolyte choice than PC.This study provides direct experimental evidence in elucidating the differences in interfacial performance between EC and PC,facilitating a deeper understanding of battery interface reactions and guiding the design of high-performance lithium-ion batteries.
基金The computational resources were provided by the Cambridge Tier-2 sys-tem operated by the University of Cambridge Research Computing Service and funded by the UK EPSRC(Grant No.EP/P020259/1).
文摘Evidence for metallization in dense oxygen has been reported for over 30 years[Desgreniers et al.,J.Phys.Chem.94,1117(1990)]at a now routinely accessible 95 GPa[Shimizu et al.,Nature 393,767(1998)].However,despite the longevity of this result and the technological advances since,the nature of the metallic phase remains poorly constrained[Akahama et al.,Phys.Rev.Lett.74,4690(1995);Goncharov et al.,Phys.Rev.B 68,224108(2003);Ma,Phys.Rev.B 76,064101(2007);and Weck et al.,Phys.Rev.Lett.102,255503(2009)].In this work,through Raman spectroscopy,we report the distinct vibrational characteristics of metallicζ-O_(2) from 85 to 225 GPa.In comparison with numerical simulations,wefind reasonable agreement with the candidate structure up to about 150 GPa.At higher pressures,the C2/mstructure is found to be unstable and incompatible with experimental observations.Alternative candidate structures,and Ci,with C2/m C2/conly two molecules in the primitive unit cell,are found to be stable and more compatible with measurements above 175 GPa,indicative of the dissociation of(O_(2))4 units.Further,we report and discuss a strong hysteresis and metastability with the precursory phaseϵ-O_(2).Thesefindings will reinvigorate experimental and theoretical work into the dense oxygen system,which will have importance for oxygen-bearing chemistry,prevalent in the deep Earth,as well as fundamental physics.
基金supported by the Key Research and Development Program of Shaanxi(Program Nos.2022GXLH-01-20 and 2024GXYBXM-193).
文摘This article presents a compact magnetic levitation energy harvester(MLEH)with tunable resonant frequency.Unlike many of the reported tunable harvesters with unknown tuning results,the proposed MLEH can be tuned toward designated resonant frequency values within its tuning range.The targeted tuning processes is realized by a nonlinear magnet repulsive force exerted on a Halbach magnet array,combined with a calibrated scaling system.At a sinusoidal acceleration of±0.15 g,the maximum frequency tuning range of the proposed MLEH is 6.3 Hz(8.1–14.4 Hz),which is 77.8%of its resonant MLEH(8.1 Hz).At a frequency of 9.7 Hz,the output power is 462.1μW and the calculated normalized power density is 496μWcm^(−3)g^(−2).
基金supported by the National Key Program forS&TResearchand Development(No.2019YFA0307700)the National Natural Science Foundation of China(No.12174148,No.12274178,and No.12074144)the Natural Science Foundation of Jilin Province(No.20240101322JC).
文摘We experimentally investigate the vibrational state distribution of the cations after carbon monoxide(CO)molecules are irradiated by strong laser fields.Vibrational-resolved fluorescent spectrum is observed,which can be well assigned as the A^(2)Π(υ′=0-3)→X^(2)Σ+(υ″=0-3)transitions of the cations CO+,indicating the strong field ionization of the inner molecular orbital of CO.Relative distribution of vibrational states A^(2)Π(υ′=0-3)of CO+is retrieved from the measured spectrum and the Franck-Condon factors.It is found that the vibrational state distribution in strong field ionization of CO apparently deviates from the Franck-Condon-like distribution,but is in good agreement with the calculations,in which we include both the ionization rate and the overlapping between the vibrational wavefunctions of the neutral and cationic electronic states.The distribution of CO+(A^(2)Π,υ′)strongly depends on the laser intensity but is less dependent on the laser ellipticity.Analysis indicates the inter-nuclear distance-dependent ionization plays a significant role in the vibrational state distribution induced by strong field ionization of CO molecules.
基金supported by the National Natural Science Foundation of China(Nos.22473104 and 22073088).
文摘Threshold photoelectron spectrum of CH_(2)F_(2)in the photon energy range of 12.45-14.10 eV was re-investigated by means of a combination of photo-electron-photoion coincidence experiments and density functional theory calculations.A series of vibrational peaks were distinctly observed in this range.Using optimized geometries and vibrational frequencies of the CH_(2)F_(2)neutral and its cation in ground state at the M06-2X/cc-pVTZ level of theory,Franck-Condon factor simulations were conducted.Taking into account anharmonicity influences,a perfect agreement between the simulated and experimental spectra has been achieved.From the reliable vibrational assignments,adiabatic and vertical ionization energies of CH_(2)F_(2)are derived as 12.371±0.010 eV and 13.281±0.010 eV,respectively.In addition,the experimental frequencies of four vibrational modes with ai symmetry for CH_(2)F_(2)+(X^(2)B_(1))ions are determined.
基金carried out with financial support from the Russian Ministry of Education and Science,project FSNM-2023-0004“Hydrogen energy.Materials and technology for storage,transportation and use of hydrogen and hydrogen-containing mixtures”.
文摘Transporting and storing hydrogen is a complex technological task.A typical problem relates to the need to minimize the strength of fluid motion and heat transfer near the walls of the container.In this work this problem is tackled numerically assuming an infinite cavity of pipe square cross-section,located in a constant external temperature gradient.In particular,a method based on the application of vibrations to suppress the gravitational convection mechanism is explored.A parametric investigation is conducted and the limits of applicability of the method for small Grashof numbers(10e4)are determined.It is shown that it is possible to minimize the intensity of the vibrogravitational flow for any values of the problem parameters if correction factors are specified.The results obtained can be applied in technological processes associated with the transportation,storage and use of hydrogen:pumping the working fluid through pipes,storage in tanks,as well as flow processes in the combustion chambers of power plants.
基金supported by the National Natural Science Foundation of China (52071055)the Fundamental Research Funds for the Central Universities (Grant No.DUT22QN237).
文摘Important challenges must be addressed to make wind turbines sustainable renewable energy sources.A typical problem concerns the design of the foundation.If the pile diameter is larger than that of the jacket platform,traditional mechanical models cannot be used.In this study,relying on the seabed soil data of an offshore wind farm,the m-method and the equivalent embedded method are used to address the single-pile wind turbine foundation problem for different pile diameters.An approach to determine the equivalent pile length is also proposed accordingly.The results provide evidence for the effectiveness and reliability of the model based on the equivalent embedded method.
文摘The design of a ship is a process facilitated by different parallel departments.Specialists from various disciplines jointly work on a project,eventually covering the entire process.Though simultaneously,these disciplines are often subject to a hierarchy,either clearly defined or dictated by necessity.Within these branches,despite a growing interest in enhancing the comfort on board ships,noise and vibration design is among the most sacrificed.Compared to hydrodynamic or structural modifications,efforts devoted to improving vibrational comfort are generally slightly impactful and costly.Consequently,these improvements are often relegated to the final stages of the design procedure.The underestimation of noise and vibrational comfort design can generate serious,unexpected issues emerging only in the advanced phases of the ship’s life,and post-construction interventions are often needed.This case is exemplified in the current study,where the crew of the research vessel Mintis,a catamaran-type hull,reported discomfort in the navigation wheelhouse.A measurement campaign was set up to assess the complaints of the operating personnel regarding the high vibrational levels.Subsequent to the measurements,a numerical simulation,specifically comprising a modal analysis,was conducted to investigate the nature of the disturbance and distinguish the underlying mechanism at its origin.This paper meticulously presents and discusses the strategy undertaken to analyze and solve the vibrational problem encountered on board,with particular attention to the criteria and the modeling considerations adopted.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60971009 and 61001011)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20090142110019)+1 种基金the Natural Science Foundation of Hubei Province, China (Grant No. 2010CDB02701)the Fundamental Research Funds for the Central Universities, China (Grant No. 2012QN083)
文摘Decoupling the complicated vibrational-vibrational （V-V） coupling of a multimode vibrational relaxation remains a challenge for analyzing the sound relaxational absorption in multi-component gas mixtures. In our previous work [Acta Phys. Sin. 61 174301 （2012）], an analytical model to predict the sound absorption from vibrational relaxation in a gas medium is proposed. In this paper, we develop the model to decouple the V-V coupled energy to each vibrationaltranslational deexcitation path, and analyze how the multimode relaxations form the peaks of sound absorption spectra in gas mixtures. We prove that a multimode relaxation is the sum of its decoupled single-relaxation processes, and only the decoupled process with a significant isochoric-molar-heat can be observed as an absorption peak. The decoupling model clarifies the essential processes behind the peaks in spectra arising from the multimode relaxations in multi-component gas mixtures. The simulation validates the proposed decoupling model.
文摘Characterization of real-time and ultrafast motions of the complex molecules at surface and interface is critical to understand how interracial molecules function. It requires to develop surface-sensitive, fast-identification, and time-resolved techniques. In this study, we employ several key technical procedures and successfully develop a highly sensitive femtosecond time-resolved sum frequency generation vibrational spectroscopy （SFG-VS） system. This system is able to measure the spectra with two polarization combinations （ssp and ppp, or psp and ssp） simultaneously. It takes less than several seconds to collect one spectrum. To the best of our knowledge, it is the fastest speed of collecting SFG spectra reported by now. Using the time-resolved measurement, ultrafast vibrational dynamics of the N-H mode of α-helical peptide at water interface is determined. It is found that the membrane environment does not affect the N-H vibrational relaxation dynamics. It is expected that the time-resolved SFG system will play a vital role in the deep understanding of the dynamics and interaction of the complex molecules at surface and interface. Our method may also provide an important technical proposal for the people who plan to develop time-resolved SFG systems with simultaneous measurement of multiple polarization combinations.
基金Acknowledgment： This work was supported by the National Natural Science Foundation of China （No.20673107 and No.20873133）, the National Basic Research Program of China （No.2007CB815203 and No.2010CB923302）, the Chinese Academy of Sciences （No.KJCX2-YW-N24）, and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, Ministry of Education of China.
文摘Based on previous laser-induced fluorescence excitation spectroscopy work, the vibrational constants of neutral FeS in the X5 △ electronic state were obtained by directly mapping the ground-state vibrational levels up to v＂=3 using conventional laser-induced dispersed fluorescence spectroscopy. The vibrational frequency of FeS（X5 △） （518±5 cm-1） agrees well with that reported in a recent PES measurement （520±30 cm-1） [J. Phys. Chem. A 107, 2821 （2003）] which is the only one prior experimental vibrational frequency value for the 5 △ state of FeS. Careful comparisons of our experimental results and those documented in the literature （mainly from theoretical predictions） suggest that the ground state of FeS is 5 △ state.
文摘An algebraic Harniltonian for the two coupled nonlinear vibrations of highly excited nonrigid molecule HCP was presented. The Hamiltonian reduces to the conventional one in a limit which was expressed in terms of harmonic oscillator operators. It showed that the algebraic model can better reproduce the data than the conventional model by fitting the observed data of HCP.
基金This work was supported by the National Natural Science Foundation of China （No.20273066）.
文摘The potential energy curves of the ground state X2∑＋g of the fluorine molecule have been accurately reconstructed employing the Ryderg-Klein-Rees （RKR） method extrapolated by a Hulburt and Hirschfeler potential function for longer internuclear distances. Solving the corresponding radial one-dimensional Schr？dinger equation of nuclear motion yields 22 bound vibrational levels above v=0. The comparison of these theoretical levels with the experimental data yields a mean absolute deviation of about 7.6 cm^-1 over the 23 levels. The highest vibrational level energy obtained using this method is 13308.16 cm？1 and the relative deviation compared with the experimental datum of 13408.49 cm^-1 is only 0.74%. The value from our method is much closer and more accurate than the value obtained by the quantum mechanical ab initio method by Bytautas. The reported agreement of the vibrational levels and dissociation energy with experiment is contingent upon the potential energy curve of the F2 ground state.
文摘In this paper, we have applied the Lie algebraic model to nano-bio molecules to determine the vibrational spectra of different stretching and bending vibrational modes. The determined vibrational energy levels by the Lie algebraic model are compared with the experimental data. The results from the theoretical mode[ are consistent with the experimental data. The vibrational energy levels are clustering in the excited states.
基金supported by the National Natural Science Foundation of China(Grant No.11647058)the Fund for Sichuan Distinguished Scientists(Grant No.2015JQ0042)the Youth Innovation Team of the Education Department of Sichuan Province,China(Grant No.14TD0013)
文摘The vibrational wave function of the target theoretically plays an important role in the calculation of vibrational excitation cross sections. By a careful study of the differential cross sections resulting from different vibrational wave functions we find that cross sections are susceptible to vibrational wave functions. Minor changes in the vibration wave lhnction may cause a significant change in the cross section. Even more surprising is that by selecting a few numbers of potential models （which determine the vibrational wave functions） we can often calculate the differential scattering cross section in much closer agreement with experiment in the framework of body-frame vibrational close-coupling theory, which suggest that an accurate potential energy may play a more important role in scattering than we thought betbre.
