In the present study,a coaxial transmission line resonator is constructed,which is always capable of generating cold microwave plasma jet plumes in ambient air in spite of using argon,nitrogen,or even air,respectively...In the present study,a coaxial transmission line resonator is constructed,which is always capable of generating cold microwave plasma jet plumes in ambient air in spite of using argon,nitrogen,or even air,respectively.Although the different kinds of working gas induce the different discharge performance,their ionization processes all indicate that the ionization enhancement has taken place twice in each pulsed periods,and the electron densities measured by the method of microwave Rayleigh scattering are higher than the amplitude order of 10^(18)m^(-3).The tail region of plasma jets all contain a large number of active particles,like NO,O,emitted photons,etc,but without O_(3).The formation mechanism and the distinctive characteristics are attributed to the resonance excitation of the locally enhanced electric fields,the ionization wave propulsion,and the temporal and spatial distribution of different particles in the pulsed microwave plasma jets.The parameters of plasma jet could be modulated by adjusting microwave power,modulation pulse parameters(modulation frequency and duty ratio),gas type and its flow rate,according to the requirements of application scenarios.展开更多
The important features of the rescattering trajectories in strong field ionization process such as the cutoff of the return energy at 3.17Up and that of the final energy at 10Up are obtained, based on the adiabatic ap...The important features of the rescattering trajectories in strong field ionization process such as the cutoff of the return energy at 3.17Up and that of the final energy at 10Up are obtained, based on the adiabatic approximation in which the initial momentum of the electron is assumed to be zero. We theoretically study the nonadiabatic effect by assuming a nonzero initial momentum on the rescattering trajectories based on the semiclassical simpleman model. We show that the nonzero initial momentum will modify both the maximal return energy at collision and the final energy after backward scattering, but in different ways for odd and even number of return trajectories. The energies are increased for even number of returns but are decreased for odd number of returns when the nonzero （positive or negative） initial momentum is applied.展开更多
Multiply charged ions of Ar and NO were observed in MPI experiment Of NO/Ar with TOF-MS. A delayable pulsed acceleration field wn applied tO investigate the effect of the photoelectrons on the formation of the multi...Multiply charged ions of Ar and NO were observed in MPI experiment Of NO/Ar with TOF-MS. A delayable pulsed acceleration field wn applied tO investigate the effect of the photoelectrons on the formation of the multiply charged ions. The multiply charged ions were suggested to be produced by photoelectron impact ionization, in the region bentween the extractor grid and the repeller plate, step by step, from neutral species and lower charged ions. The 50-60ns of FWHM of the ion peaks implies that the pulse width of the photoelectrons should be shorter considering the broadening effect during the ionization process.展开更多
The most recent spectroscopic studies of moving-single bubble sonoluminescence(MSBSL)and multi-bubble sonoluminescence(MBSL)have revealed that hydrated electrons(e^(-)_(aq))are generated in MSBSL but absent in MBSL.To...The most recent spectroscopic studies of moving-single bubble sonoluminescence(MSBSL)and multi-bubble sonoluminescence(MBSL)have revealed that hydrated electrons(e^(-)_(aq))are generated in MSBSL but absent in MBSL.To explore the mechanism of this phenomenon,we numerically simulate the ionization processes in single-and multi-bubble sonoluminescence in aqueous solution of terbium chloride(TbCl_(3)).The results show that the maximum degree of ionization of single-bubble sonoluminescence(SBSL)is approximately 10000 times greater than that of MBSL under certain special physical parameters.The hydrated electrons(e^(-)_(aq))formed in SBSL are far more than those in MBSL provided these electrons are ejected from a bubble into a liquid.Therefore,the quenching of e^(-)_(aq)to SBSL spectrum is stronger than that of the MBSL spectrum.This may be the reason that the trivalent terbium[Tb(Ⅲ)]ion line intensities from SBSL in the TbCl_(3) aqueous solutions with the acceptor of e^(-)_(aq)are stronger than those of TbCl_(3) aqueous solutions without the acceptor of e^(-)_(aq).Whereas the Tb(Ⅲ)ion line intensities from MBSL are not variational,which is significant for exploring the mechanism behind the cavitation and sonoluminescence.展开更多
We investigate the above-threshold ionization of an atom in a combined infrared （IR） and extreme ultraviolet （XUV） two-color laser field and focus on the role of XUV field in the high-order above-threshold ionizat...We investigate the above-threshold ionization of an atom in a combined infrared （IR） and extreme ultraviolet （XUV） two-color laser field and focus on the role of XUV field in the high-order above-threshold ionization （HATI） process. It is demonstrated that, in stark contrast to previous studies, the XUV laser may play a significant role in atomic HATI process, and in particular, the XUV laser can accelerate the ionized electron in a quantized way during the collision between the electron and its parent ion. This process cannot be explained by the elassical three-step model Our results indicate that the previously well-established concept that HATI is an elastic recollision process is broken down.展开更多
Different SiGe processes and device designs are the critical influences of ionizing radiation damage. Based on the different ionizing radiation damage in SiGe HBTs fabricated by Huajie and an IBM SiGe process, quantit...Different SiGe processes and device designs are the critical influences of ionizing radiation damage. Based on the different ionizing radiation damage in SiGe HBTs fabricated by Huajie and an IBM SiGe process, quantitatively numerical simulation of ionizing radiation damage was carried out to explicate the distribution of radiation-induced charges buildup in KT9041 and IBM SiGe HBTs. The sensitive areas of the EB-spacer and isolation oxide of KT9041 are much larger than those of the IBM SiGe HBT, and the distribution of charge buildup in KT9041 is several orders of magnitude greater than that of the IBM SiGe HBT. The result suggests that the simulations are consistent with the experiment, and indicates that the geometry of the EB-spacer, the area of the Si/SiO2 interface and the isolation structure could be contributing to the different ionizing radiation damage.展开更多
An experimental platform of a pulse detonation engine(PDE) was established to study the effect of different K_2 CO_3 ionized seed mass contents on the detonation process.The pressure and ion concentration were detecte...An experimental platform of a pulse detonation engine(PDE) was established to study the effect of different K_2 CO_3 ionized seed mass contents on the detonation process.The pressure and ion concentration were detected in the detonation process of the PDE with different contents of ionized seeds.The initiation process of the PDE at different ignition frequencies was studied.The results show that the gas conductivity in the detonation process increased by adding ionized seeds to the PDE tube,and the conductivity increased with the increase in ionized seed mass content.With the increase in ionized seed mass content,the range of the conductivity decreased.The PDE was successfully ignited and formed a stable detonation wave at ignition frequencies of 5 Hz and 10 Hz,and the peak pressure of the stable detonation with the ignition frequency of 5 Hz was 17% higher than that with an ignition frequency of 10 Hz.The detonation wave intensity was weake ned and dege nerated to a shock wave that propagated in the tube without the fuel filled at the ignition frequency of 20 Hz.展开更多
The ionization dynamics of two-electron atom in an intense laser field is studied by the Bohmian mechanics(BM)theory, and the xenon atomic potential function is used as a model. The single ionization process and doubl...The ionization dynamics of two-electron atom in an intense laser field is studied by the Bohmian mechanics(BM)theory, and the xenon atomic potential function is used as a model. The single ionization process and double ionization process are calculated by the BM theory and their results are in good agreement with those calculated by numerically solving the time-dependent Schrodinger equation. The analyses of the types, trajectories, and forces of Bohmian particles(BPs)undergoing the single and double ionizations indicate that the re-collision process accounts for a considerable proportion in the singly ionized cases. Furthermore, the analysis of the work done by the external force acting on the BPs shows that the quantum force plays an important role in the re-collision process. This work is helpful in understanding the ionization of two-electron atom in an intense laser field.展开更多
The mechanism of precursor ionization ahead of strong shock waves has been studied in a low density shock tube. The experimental results are illustrated with Arrhenius plots with kink points dividing them into two par...The mechanism of precursor ionization ahead of strong shock waves has been studied in a low density shock tube. The experimental results are illustrated with Arrhenius plots with kink points dividing them into two parts with apparent activation energy ratio 1:2, namely with the values 7.7 eV and 15.3 eV, and varying with first and third power of the density respectively. A model is proposed to interpret the facts where the process taking place in the precursor region is a two step photo ionization accompanied with the drift flow effect of the gas relative to the shock wave or the ionization recombination effect according to whether the shock speed and initial density are low enough. The product of the A-A collision excitation cross section coefficient S* multiplied by the radiation cross section Q of Argon S×Q=1×10^(-36)(cm^4eV^(-1)) and the three body recombination coefficient of Argon at room temperature k_(ra)=1×10^(-24)(cm^(-6)s^(-1)).展开更多
The behavior of N-methylidenemalonates of 3-arylaminoindoles and p-dimetylamino-N-phenylanyline (M = ANa) was studied during their analysis with ESI mass spectrometer operated in negative (NI) and positive (PI) ion mo...The behavior of N-methylidenemalonates of 3-arylaminoindoles and p-dimetylamino-N-phenylanyline (M = ANa) was studied during their analysis with ESI mass spectrometer operated in negative (NI) and positive (PI) ion modes. Anions [A] and both [M + H]+ and [M + Na]+ were recorded under conditions of the NI-ESI and PI-ESI, respectively. The fragmentation processes of [A] and [M + H]+ were found that probably occurred as “insource collusion induced dissociation”. The main paths for [A] proved to be elimination of CO2 and breakage of the N-methylidenemalonate bond. A route [A]- - CO2 - ROH (R = Me or Et) was less expressed and occurred for the indolyl-containing compounds with the NH bond only. Experiments employing heavy water demonstrated the isotope exchange to occur involving the hydrogen atom of this bond. This and other facts evidenced that the last fragmentation included abstraction of just this atom. Quantum-chemical calculations allowed picking out a structure for the product ion from the possible ones. The calculations also indicated that the protonation of M occurred at the anionic oxygen atom of the malonate moiety. The fragmentation of [M + H]+ ions included elimination of two water molecules that was supported by their MS2 spectra. A common feature of the NI- and PI-ESI mass spectra was the presence of oligomeric ions, up to tetramers and trimers for the NI- and PI-ESI ones, respectively. The oligomers were formed by interaction of the corresponding ions with neutral molecules. When ions contained extra hydrogen atoms, they were introduced by hydrolysis.展开更多
We investigate propagation of dust ion acoustic solitary wave(DIASW)in a multicomponent dusty plasma with adiabatic ions,superthermal electrons,and stationary dust.The reductive perturbation method is employed to deri...We investigate propagation of dust ion acoustic solitary wave(DIASW)in a multicomponent dusty plasma with adiabatic ions,superthermal electrons,and stationary dust.The reductive perturbation method is employed to derive the damped Korteweg-de Vries(DKdV)equation which describes DIASW.The result reveals that the adiabaticity of ions significantly modifies the basic features of the DIASW.The ionization effect makes the solitary wave grow,while collisions reduce the growth rate and even lead to the damping.With the increases in ionization cross sectionΔσ/σ_(0),ion-to-electron density ratioδ_(ie)and superthermal electrons parameterκ,the effect of ionization on DIASW enhances.展开更多
We present in this paper an investigation of the nonlinear process of above-threshold ionization. The process arises when an atomic or molecular system, exposed to an intense laser pulse, continues to absorb more phot...We present in this paper an investigation of the nonlinear process of above-threshold ionization. The process arises when an atomic or molecular system, exposed to an intense laser pulse, continues to absorb more photons than that needed for the ionization to occur. We trigger this nonlinear process in a simple molecular system by exposing it to an intense transform-limited Gaussian laser pulse of 267-nm wavelength which is the third harmonic of an 800-nm wavelength Tisapphire laser. We explore the characteristics of the process by analyzing the kinetic-energy spectra of the electrons ejected from the molecular system under different laser peak intensities.展开更多
Circadian rhythm is a self-sustaining endogenous oscillation that serves as an internal timekeeping mechanism adapted to the Earth’s 24-h rotational schedule.It exists ubiquitously in nearly all organisms,from prokar...Circadian rhythm is a self-sustaining endogenous oscillation that serves as an internal timekeeping mechanism adapted to the Earth’s 24-h rotational schedule.It exists ubiquitously in nearly all organisms,from prokaryotes to mammals,and regulates diverse physiological and behavioral processes by synchronizing them with environmental fluctuations[1].Previous reports indicated that circadian rhythms exist in biological individuals and cells cultured in vitro[2].The mammalian circadian rhythm system consists of a central pacemaker located in the suprachiasmatic nucleus(SCN)of the hypothalamus,which coordinates peripheral rhythms through the sympathetic and parasympathetic nervous systems[3].This hierarchical mechanism uses neural populations as optimal models for circadian rhythm research.展开更多
The efficient and sustainable removal of refractory high ionization potential(high-IP)organic pollutants remains challenging due to their redox inertness and poor interfacial electron transfer.Herein,we report a suspe...The efficient and sustainable removal of refractory high ionization potential(high-IP)organic pollutants remains challenging due to their redox inertness and poor interfacial electron transfer.Herein,we report a suspended photo-Fenton membrane (2D-C_(3)N_(4)/Fe-N-C/GO) that circumvents these limitations via a self-sufficient oxidant generation pathway,enabling low-carbon abatement of high-IP pollutants.This multifunctional architecture couples the visible-light-driven production of hydrogen peroxide(H_(2)O_(2)) by two-dimensional carbon nitride(2D-C_(3)N_(4)) with the Fe-N-C mediated adsorption and activation of electron-deficient species via pyridinic N-Fe^(2+)/Fe^(3+) redox pairs.Under light irradiation,photogenerated electrons continuously regenerate Fe^(2+) from Fe^(3+),sustaining reactive oxygen species(·OH)production and promoting efficient oxidative mineralization.The system demonstrates robust long-term performance in both synthetic and real wastewater matrices,achieving superior degradation and chemical oxygen demand(COD)removal.Life cycle assessment(LCA)confirms its environmental superiority over conventional homogeneous Fenton processes,with markedly reduced carbon emissions and ecological impacts.This work offers a mechanistically insightful and practically viable platform for the green,efficient,and durable remediation of high-IP organic pollutants,providing conceptual guidance for next-generation catalytic wastewater treatment technologies.展开更多
Capillary electrophoresis coupled to mass spectrometry（CE–MS） was used for the analysis of naphthenic acid fraction compounds（NAFCs） of oil sands process-affected water（OSPW）. A standard mixture of amine-deriva...Capillary electrophoresis coupled to mass spectrometry（CE–MS） was used for the analysis of naphthenic acid fraction compounds（NAFCs） of oil sands process-affected water（OSPW）. A standard mixture of amine-derivatized naphthenic acids is injected directly onto the CE column and analyzed by CE–MS in less than 15 min. Time of flight MS analysis（TOFMS）, optimized for high molecular weight ions, showed NAFCs between 250 and 800 m/z. With a quadrupole mass analyzer, only low-molecular weight NAFCs（between 100 and 450 m/z） are visible under our experimental conditions. Derivatization of NAFCs consisted of two-step amidation reactions mediated by 1-ethyl-3-（3-dimethylaminopropyl）carbodiimide（EDC）, or mediated by a mixture of EDC and N-hydroxysuccinimide, in dimethyl sulfoxide, dichloromethane or ethyl acetate. The optimum background electrolyte composition was determined to be 30%（V/V） methanol in water and 2%（V/V） formic acid. NAFCs extracted from OSPW in the Athabasca oil sands region were used to demonstrate the feasibility of CE–MS for the analysis of NAFCs in environmental samples, showing that the labeled naphthenic acids are in the mass range of 350 to 1500 m/z.展开更多
The present work describes the amount of Di-n- butyl phosphate (DBP) produced when PUREX solvent (30%tri-n-butyl phosphate (TBP) mixed with 70% hydrocarbon diluent) is exposed to intensive radiolytic and chemical at- ...The present work describes the amount of Di-n- butyl phosphate (DBP) produced when PUREX solvent (30%tri-n-butyl phosphate (TBP) mixed with 70% hydrocarbon diluent) is exposed to intensive radiolytic and chemical at- tack during the separation of uranium and plutonium from fission products of FBTR mixed carbide fuel reprocessing solution. DBP is the major degradation product of Tri-n-butyl phosphate (TBP). Amount of DBP formed in the lean organic streams of different fuel burn-up FBTR carbide fuel reprocessing solutions were analyzed by Gas Chromatographic technique. The method is based on the preparation of diazo methane and conversion of non-volatile Di-n-butyl phosphate in to volatile and stable derivatives by the action of diazomethane and then determined by Gas Chromatography (GC). A calibration graph was made for DBP over a concentration in the range from 200 to 1800 ppm with correlation coefficient of 0.99587 and RSD 1.2%. The degraded 30% TBP-NPH solvent loaded with heavy metal ions like uranium was analyzed after repeated use and results are compared with standard ion chromatographic technique. A column comparison study to select of proper gas chromatographic column for the separation of DBP from other components in a single aliquot of injection is also examined.展开更多
基金supported by National Natural Science Foundation of China (Nos. 52177126 and 11575003)Anhui Province University Excellent Youth Foundation (No. gxyqzd2021104)
文摘In the present study,a coaxial transmission line resonator is constructed,which is always capable of generating cold microwave plasma jet plumes in ambient air in spite of using argon,nitrogen,or even air,respectively.Although the different kinds of working gas induce the different discharge performance,their ionization processes all indicate that the ionization enhancement has taken place twice in each pulsed periods,and the electron densities measured by the method of microwave Rayleigh scattering are higher than the amplitude order of 10^(18)m^(-3).The tail region of plasma jets all contain a large number of active particles,like NO,O,emitted photons,etc,but without O_(3).The formation mechanism and the distinctive characteristics are attributed to the resonance excitation of the locally enhanced electric fields,the ionization wave propulsion,and the temporal and spatial distribution of different particles in the pulsed microwave plasma jets.The parameters of plasma jet could be modulated by adjusting microwave power,modulation pulse parameters(modulation frequency and duty ratio),gas type and its flow rate,according to the requirements of application scenarios.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11425414 and 11504215the Scientific Research Training Program of Shanxi University
文摘The important features of the rescattering trajectories in strong field ionization process such as the cutoff of the return energy at 3.17Up and that of the final energy at 10Up are obtained, based on the adiabatic approximation in which the initial momentum of the electron is assumed to be zero. We theoretically study the nonadiabatic effect by assuming a nonzero initial momentum on the rescattering trajectories based on the semiclassical simpleman model. We show that the nonzero initial momentum will modify both the maximal return energy at collision and the final energy after backward scattering, but in different ways for odd and even number of return trajectories. The energies are increased for even number of returns but are decreased for odd number of returns when the nonzero （positive or negative） initial momentum is applied.
文摘Multiply charged ions of Ar and NO were observed in MPI experiment Of NO/Ar with TOF-MS. A delayable pulsed acceleration field wn applied tO investigate the effect of the photoelectrons on the formation of the multiply charged ions. The multiply charged ions were suggested to be produced by photoelectron impact ionization, in the region bentween the extractor grid and the repeller plate, step by step, from neutral species and lower charged ions. The 50-60ns of FWHM of the ion peaks implies that the pulse width of the photoelectrons should be shorter considering the broadening effect during the ionization process.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11864007 and 11564006)。
文摘The most recent spectroscopic studies of moving-single bubble sonoluminescence(MSBSL)and multi-bubble sonoluminescence(MBSL)have revealed that hydrated electrons(e^(-)_(aq))are generated in MSBSL but absent in MBSL.To explore the mechanism of this phenomenon,we numerically simulate the ionization processes in single-and multi-bubble sonoluminescence in aqueous solution of terbium chloride(TbCl_(3)).The results show that the maximum degree of ionization of single-bubble sonoluminescence(SBSL)is approximately 10000 times greater than that of MBSL under certain special physical parameters.The hydrated electrons(e^(-)_(aq))formed in SBSL are far more than those in MBSL provided these electrons are ejected from a bubble into a liquid.Therefore,the quenching of e^(-)_(aq)to SBSL spectrum is stronger than that of the MBSL spectrum.This may be the reason that the trivalent terbium[Tb(Ⅲ)]ion line intensities from SBSL in the TbCl_(3) aqueous solutions with the acceptor of e^(-)_(aq)are stronger than those of TbCl_(3) aqueous solutions without the acceptor of e^(-)_(aq).Whereas the Tb(Ⅲ)ion line intensities from MBSL are not variational,which is significant for exploring the mechanism behind the cavitation and sonoluminescence.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11474348,61275128,11274050,11334009and 11425414the NSERC of Canada+1 种基金the Canadian Computing Facilities of SHARCnet and ACEnetthe National Basic Research Program of China under Grant No 2013CB922200
文摘We investigate the above-threshold ionization of an atom in a combined infrared （IR） and extreme ultraviolet （XUV） two-color laser field and focus on the role of XUV field in the high-order above-threshold ionization （HATI） process. It is demonstrated that, in stark contrast to previous studies, the XUV laser may play a significant role in atomic HATI process, and in particular, the XUV laser can accelerate the ionized electron in a quantized way during the collision between the electron and its parent ion. This process cannot be explained by the elassical three-step model Our results indicate that the previously well-established concept that HATI is an elastic recollision process is broken down.
基金supported by the National Natural Science Foundation of China(Grant Nos.61274106 and 61574171)
文摘Different SiGe processes and device designs are the critical influences of ionizing radiation damage. Based on the different ionizing radiation damage in SiGe HBTs fabricated by Huajie and an IBM SiGe process, quantitatively numerical simulation of ionizing radiation damage was carried out to explicate the distribution of radiation-induced charges buildup in KT9041 and IBM SiGe HBTs. The sensitive areas of the EB-spacer and isolation oxide of KT9041 are much larger than those of the IBM SiGe HBT, and the distribution of charge buildup in KT9041 is several orders of magnitude greater than that of the IBM SiGe HBT. The result suggests that the simulations are consistent with the experiment, and indicates that the geometry of the EB-spacer, the area of the Si/SiO2 interface and the isolation structure could be contributing to the different ionizing radiation damage.
基金supported by the National Natural Science Foundation of China(No.11802039,No.51605046)the Jiangsu Natural Science Foundation of China(No.BK20160406)。
文摘An experimental platform of a pulse detonation engine(PDE) was established to study the effect of different K_2 CO_3 ionized seed mass contents on the detonation process.The pressure and ion concentration were detected in the detonation process of the PDE with different contents of ionized seeds.The initiation process of the PDE at different ignition frequencies was studied.The results show that the gas conductivity in the detonation process increased by adding ionized seeds to the PDE tube,and the conductivity increased with the increase in ionized seed mass content.With the increase in ionized seed mass content,the range of the conductivity decreased.The PDE was successfully ignited and formed a stable detonation wave at ignition frequencies of 5 Hz and 10 Hz,and the peak pressure of the stable detonation with the ignition frequency of 5 Hz was 17% higher than that with an ignition frequency of 10 Hz.The detonation wave intensity was weake ned and dege nerated to a shock wave that propagated in the tube without the fuel filled at the ignition frequency of 20 Hz.
基金Project supported by the Jilin Provincial Science and Technology Development Plan Program for Excellent Youth Talents,China(Grant No.20180520174JH)the National Natural Science Foundation of China(Grant Nos.11704145,11904050,11774129,11747007,11534004,and 12074145).
文摘The ionization dynamics of two-electron atom in an intense laser field is studied by the Bohmian mechanics(BM)theory, and the xenon atomic potential function is used as a model. The single ionization process and double ionization process are calculated by the BM theory and their results are in good agreement with those calculated by numerically solving the time-dependent Schrodinger equation. The analyses of the types, trajectories, and forces of Bohmian particles(BPs)undergoing the single and double ionizations indicate that the re-collision process accounts for a considerable proportion in the singly ionized cases. Furthermore, the analysis of the work done by the external force acting on the BPs shows that the quantum force plays an important role in the re-collision process. This work is helpful in understanding the ionization of two-electron atom in an intense laser field.
基金The project supported by the National Natural Science Foundation of China
文摘The mechanism of precursor ionization ahead of strong shock waves has been studied in a low density shock tube. The experimental results are illustrated with Arrhenius plots with kink points dividing them into two parts with apparent activation energy ratio 1:2, namely with the values 7.7 eV and 15.3 eV, and varying with first and third power of the density respectively. A model is proposed to interpret the facts where the process taking place in the precursor region is a two step photo ionization accompanied with the drift flow effect of the gas relative to the shock wave or the ionization recombination effect according to whether the shock speed and initial density are low enough. The product of the A-A collision excitation cross section coefficient S* multiplied by the radiation cross section Q of Argon S×Q=1×10^(-36)(cm^4eV^(-1)) and the three body recombination coefficient of Argon at room temperature k_(ra)=1×10^(-24)(cm^(-6)s^(-1)).
文摘The behavior of N-methylidenemalonates of 3-arylaminoindoles and p-dimetylamino-N-phenylanyline (M = ANa) was studied during their analysis with ESI mass spectrometer operated in negative (NI) and positive (PI) ion modes. Anions [A] and both [M + H]+ and [M + Na]+ were recorded under conditions of the NI-ESI and PI-ESI, respectively. The fragmentation processes of [A] and [M + H]+ were found that probably occurred as “insource collusion induced dissociation”. The main paths for [A] proved to be elimination of CO2 and breakage of the N-methylidenemalonate bond. A route [A]- - CO2 - ROH (R = Me or Et) was less expressed and occurred for the indolyl-containing compounds with the NH bond only. Experiments employing heavy water demonstrated the isotope exchange to occur involving the hydrogen atom of this bond. This and other facts evidenced that the last fragmentation included abstraction of just this atom. Quantum-chemical calculations allowed picking out a structure for the product ion from the possible ones. The calculations also indicated that the protonation of M occurred at the anionic oxygen atom of the malonate moiety. The fragmentation of [M + H]+ ions included elimination of two water molecules that was supported by their MS2 spectra. A common feature of the NI- and PI-ESI mass spectra was the presence of oligomeric ions, up to tetramers and trimers for the NI- and PI-ESI ones, respectively. The oligomers were formed by interaction of the corresponding ions with neutral molecules. When ions contained extra hydrogen atoms, they were introduced by hydrolysis.
基金supported by the Project of Scientific and Technological Innovation Base of Jiangxi Province,China (Grant No.20203CCD46008)the Key R&D Plan of Jiangxi Province,China (Grant No.20223BBH80006)+1 种基金the Natural Science Foundation of Jiangxi Province,China (Grant No.20212BAB211025)the Jiangxi Province Key Laboratory of Fusion and Information Control (Grant No.20171BCD40005)。
文摘We investigate propagation of dust ion acoustic solitary wave(DIASW)in a multicomponent dusty plasma with adiabatic ions,superthermal electrons,and stationary dust.The reductive perturbation method is employed to derive the damped Korteweg-de Vries(DKdV)equation which describes DIASW.The result reveals that the adiabaticity of ions significantly modifies the basic features of the DIASW.The ionization effect makes the solitary wave grow,while collisions reduce the growth rate and even lead to the damping.With the increases in ionization cross sectionΔσ/σ_(0),ion-to-electron density ratioδ_(ie)and superthermal electrons parameterκ,the effect of ionization on DIASW enhances.
文摘We present in this paper an investigation of the nonlinear process of above-threshold ionization. The process arises when an atomic or molecular system, exposed to an intense laser pulse, continues to absorb more photons than that needed for the ionization to occur. We trigger this nonlinear process in a simple molecular system by exposing it to an intense transform-limited Gaussian laser pulse of 267-nm wavelength which is the third harmonic of an 800-nm wavelength Tisapphire laser. We explore the characteristics of the process by analyzing the kinetic-energy spectra of the electrons ejected from the molecular system under different laser peak intensities.
基金funded by the National Natural Science Foundation of China(no.12275329,Nan Ding,and no.12175289,Jufang Wang)the West Light Foundation of The Chinese Academy of Sciences(xbzglzb2022003,Nan Ding)+2 种基金the Science and Technology Research Project of Gansu Province(no.145RTSA012,Jufang Wang,and no.21JR7RA108,Nan Ding)the Gansu Provincial Science Fund for Distinguished Young Scholars(no.22JR5RA942,Wei Wang)the CuiYing Science and Technology Innovation Program of the Second Hospital of Lanzhou University(CY2023-MS-A03,Wei Wang).
文摘Circadian rhythm is a self-sustaining endogenous oscillation that serves as an internal timekeeping mechanism adapted to the Earth’s 24-h rotational schedule.It exists ubiquitously in nearly all organisms,from prokaryotes to mammals,and regulates diverse physiological and behavioral processes by synchronizing them with environmental fluctuations[1].Previous reports indicated that circadian rhythms exist in biological individuals and cells cultured in vitro[2].The mammalian circadian rhythm system consists of a central pacemaker located in the suprachiasmatic nucleus(SCN)of the hypothalamus,which coordinates peripheral rhythms through the sympathetic and parasympathetic nervous systems[3].This hierarchical mechanism uses neural populations as optimal models for circadian rhythm research.
基金supported by the National Natural Science Foundation of China(22325602,22521201,22176060,and 22406142)the"National Key R&D Program of China"(SQ2024YFA1211001)+3 种基金the Program of Shanghai Academic/Technology Research Leader(23XD1421000)Key Laboratory of Functional Inorganic Material Chemistry(Heilongjiang University)Ministry of Education(KIM-0-2025017)State Key Laboratory of Water Pollution Control and Green Resource Recycling Foundation(PCRRF250014).
文摘The efficient and sustainable removal of refractory high ionization potential(high-IP)organic pollutants remains challenging due to their redox inertness and poor interfacial electron transfer.Herein,we report a suspended photo-Fenton membrane (2D-C_(3)N_(4)/Fe-N-C/GO) that circumvents these limitations via a self-sufficient oxidant generation pathway,enabling low-carbon abatement of high-IP pollutants.This multifunctional architecture couples the visible-light-driven production of hydrogen peroxide(H_(2)O_(2)) by two-dimensional carbon nitride(2D-C_(3)N_(4)) with the Fe-N-C mediated adsorption and activation of electron-deficient species via pyridinic N-Fe^(2+)/Fe^(3+) redox pairs.Under light irradiation,photogenerated electrons continuously regenerate Fe^(2+) from Fe^(3+),sustaining reactive oxygen species(·OH)production and promoting efficient oxidative mineralization.The system demonstrates robust long-term performance in both synthetic and real wastewater matrices,achieving superior degradation and chemical oxygen demand(COD)removal.Life cycle assessment(LCA)confirms its environmental superiority over conventional homogeneous Fenton processes,with markedly reduced carbon emissions and ecological impacts.This work offers a mechanistically insightful and practically viable platform for the green,efficient,and durable remediation of high-IP organic pollutants,providing conceptual guidance for next-generation catalytic wastewater treatment technologies.
基金supported by the Environment Canada and the NSERC
文摘Capillary electrophoresis coupled to mass spectrometry（CE–MS） was used for the analysis of naphthenic acid fraction compounds（NAFCs） of oil sands process-affected water（OSPW）. A standard mixture of amine-derivatized naphthenic acids is injected directly onto the CE column and analyzed by CE–MS in less than 15 min. Time of flight MS analysis（TOFMS）, optimized for high molecular weight ions, showed NAFCs between 250 and 800 m/z. With a quadrupole mass analyzer, only low-molecular weight NAFCs（between 100 and 450 m/z） are visible under our experimental conditions. Derivatization of NAFCs consisted of two-step amidation reactions mediated by 1-ethyl-3-（3-dimethylaminopropyl）carbodiimide（EDC）, or mediated by a mixture of EDC and N-hydroxysuccinimide, in dimethyl sulfoxide, dichloromethane or ethyl acetate. The optimum background electrolyte composition was determined to be 30%（V/V） methanol in water and 2%（V/V） formic acid. NAFCs extracted from OSPW in the Athabasca oil sands region were used to demonstrate the feasibility of CE–MS for the analysis of NAFCs in environmental samples, showing that the labeled naphthenic acids are in the mass range of 350 to 1500 m/z.
文摘The present work describes the amount of Di-n- butyl phosphate (DBP) produced when PUREX solvent (30%tri-n-butyl phosphate (TBP) mixed with 70% hydrocarbon diluent) is exposed to intensive radiolytic and chemical at- tack during the separation of uranium and plutonium from fission products of FBTR mixed carbide fuel reprocessing solution. DBP is the major degradation product of Tri-n-butyl phosphate (TBP). Amount of DBP formed in the lean organic streams of different fuel burn-up FBTR carbide fuel reprocessing solutions were analyzed by Gas Chromatographic technique. The method is based on the preparation of diazo methane and conversion of non-volatile Di-n-butyl phosphate in to volatile and stable derivatives by the action of diazomethane and then determined by Gas Chromatography (GC). A calibration graph was made for DBP over a concentration in the range from 200 to 1800 ppm with correlation coefficient of 0.99587 and RSD 1.2%. The degraded 30% TBP-NPH solvent loaded with heavy metal ions like uranium was analyzed after repeated use and results are compared with standard ion chromatographic technique. A column comparison study to select of proper gas chromatographic column for the separation of DBP from other components in a single aliquot of injection is also examined.
