Ultrafast dissociation dynamics of chloroiodomethane （CH2ICl） in the B band is studied by femtosecond time- resolved time-of-flight （TOF） mass spectrometry. Time-resolved TOF mass signal of parent ion （CH2ICl＋）...Ultrafast dissociation dynamics of chloroiodomethane （CH2ICl） in the B band is studied by femtosecond time- resolved time-of-flight （TOF） mass spectrometry. Time-resolved TOF mass signal of parent ion （CH2ICl＋） and main daughter ion （CH2Cl＋） are obtained. The curve for the transient signal of CH2ICl＋ is simple and can be well fitted by an exponential decay convoluted with a Gaussian function. The decay constant determined to be less than 35 fs reflects the lifetime of the B band. Significant substituent effects on photodissociation dynamics of CH2IC1 compared with CH3I are discussed. The dissociation time from the parent ion CH2IC1＋ to the daughter ion CH2Cl＋ is determined in the experiment. The optimized geometry of the ionic state of CH2ICl and the ionization energy are calculated for further analysis of the measurements. In addition, compared with the parent ion, a new decay component with time constant of -596 fs is observed for CH2Cl＋, and reasonable mechanisms are proposed for the explanation.展开更多
In broadband coherent anti-Stokes Raman scattering （CARS） spectroscopy with supercontinuum （SC）, the simultaneously detectable spectral coverage is limited by the spectral continuity and the simultaneity of variou...In broadband coherent anti-Stokes Raman scattering （CARS） spectroscopy with supercontinuum （SC）, the simultaneously detectable spectral coverage is limited by the spectral continuity and the simultaneity of various spectral components of SC in an enough bandwidth. By numerical simulations, the optimal experimental conditions for improving the SC are obtained. The broadband time-resolved CARS spectrography based on the SC with required temporal and spectral distributions is realised. The global molecular vibrational spectrum with well suppressed nonresonant background noise can be obtained in a single measurement. At the same time, the measurements of dephasing times of various molecular vibrational modes can be conveniently achieved from intensities of a sequence of time-resolved CARS signals. It will be more helpful to provide a complete picture of molecular vibrations, and to exhibit a potential to understand not only both the solvent dynamics and the solute-solvent interactions, but also the mechanisms of chemical reactions in the fields of biology, chemistry and material science.展开更多
The traditional Chinese medicine of Radix Hedysari plays an important role in invigorating gas for ascending, benefiting blood for promoting production of fluid, and promoting circulation for removing obstruction in c...The traditional Chinese medicine of Radix Hedysari plays an important role in invigorating gas for ascending, benefiting blood for promoting production of fluid, and promoting circulation for removing obstruction in collaterals, which is consistent with the principle of treatment for osteoporosis. This study is designed to investigate the bioactive components on increasing peak bone mass (PBM) by exploring the spectrum-effect relationship between chromatography fingerprints and effect. Multiple indicators are selected to evaluate the pharmacological activity. In fingerprints, 21 common peaks are obtained, five of which are identified. Furthermore, gray relational analysis (GRA) is a quantitative method of gray system theory and is used to describe the correlation degree of common peaks and pharmacological activities with relational value. 21 components are then divided into three different regions, of which ononin and calycosin play an extremely significant role in increasing PBM. In addition, factor analysis and hierarchical cluster analysis (HCA) are used to screen the optimal producing area for Radix Hedysari. This provides a comprehensive and efficient method to improve the quality evaluation of Radix Hedysari, confirming the bioactive components for PBM-enhancement and further develop its medicinal value.展开更多
Dependence of decamethylcyclopentasiloxane （DMCPS） organosilicon dissociation on ionized energy in the energy range of 25 eV to 70 eV is investigated by using a quadrupole mass spectrometry. At the ionized energy be...Dependence of decamethylcyclopentasiloxane （DMCPS） organosilicon dissociation on ionized energy in the energy range of 25 eV to 70 eV is investigated by using a quadrupole mass spectrometry. At the ionized energy below 55 eV, the dissociation of DMCPS is dominant. As the ionized energy is above 55 eV, the DMCPS dissociation achieves the maximum cross section, while the fragments from the DMCPS dissociation can further dissociate, which leads to a different ingredient of fragments. At the lower ionized energy of 25 eV, the main fragments are SiOC2H＋, SiCH＋, Si＋, O＋ and CH＋ ions, which shows an important effect on the SiCOH low-k film deposition.展开更多
Based on the meson-meson mixing and Regge trajectory, this paper establishes the mass relations which can describe the mass spectrum of 1^1 P1 meson state. Using these mass relations, it obtains the mass of K1B, hi （...Based on the meson-meson mixing and Regge trajectory, this paper establishes the mass relations which can describe the mass spectrum of 1^1 P1 meson state. Using these mass relations, it obtains the mass of K1B, hi （1380） and hc（1P） to be 1358.5MeV, 1468 MeV and 3543.9 MeV, respectively. The results are compared with other theoretical results and should be tested by experiments in the future.展开更多
N-ethylpyrrole is one of ethylsubstituted derivatives of pyrrole and its excited-state decay dynamics has never been explored.In this work,we investigate ultrafast decay dynamics of N-ethylpyrrole excited to the S_(1)...N-ethylpyrrole is one of ethylsubstituted derivatives of pyrrole and its excited-state decay dynamics has never been explored.In this work,we investigate ultrafast decay dynamics of N-ethylpyrrole excited to the S_(1)electronic state using a femtosecond time-resolved photoelectron imaging method.Two pump wavelengths of 241.9 and 237.7 nm are employed.At 241.9 nm,three time constants,5.0±0.7 ps,66.4±15.6 ps and 1.3±0.1 ns,are derived.For 237.7 nm,two time constants of 2.1±0.1 ps and 13.1±1.2 ps are derived.We assign all these time constants to be associated with different vibrational states in the S_(1)state.The possible decay mechanisms of different S_(1)vibrational states are briefly discussed.展开更多
Based on the mechanism for mass creation in the space-time with extradimensions proposed in our previous work, (arXiv: 1301.1405 [hep-th] 2013) we consider now the mass spectrum of vector bosons in extradimensions. It...Based on the mechanism for mass creation in the space-time with extradimensions proposed in our previous work, (arXiv: 1301.1405 [hep-th] 2013) we consider now the mass spectrum of vector bosons in extradimensions. It is shown that this spectrum is completely determined by some function of compactification length and closely related to the metric of extradimensions.展开更多
In this paper, we solve the eigen solutions to the Dirac equation with local parabolic potential which is approximately equal to the short distance potential generated by spinor itself. The energy spectrum is quite di...In this paper, we solve the eigen solutions to the Dirac equation with local parabolic potential which is approximately equal to the short distance potential generated by spinor itself. The energy spectrum is quite different from that with Coulomb potential. The mass spectrum of some bary-ons is similar to this one. The angular momentum-mass relation is quite similar to the Regge trajectories. The parabolic potential has a structure of asymptotic freedom near the center and confinement at a large distance. So, the results imply that, the local parabolic potential may be more suitable for describing the nuclear potential. The procedure of solving can also be used for some other cases of Dirac equation with complicated potential.展开更多
To study the effect of different deposition temperatures on the optical properties of porous SiC films,single crystal Si was used as the substrate,a layer of anodic aluminum oxide(AAO)film was transferred on the Si su...To study the effect of different deposition temperatures on the optical properties of porous SiC films,single crystal Si was used as the substrate,a layer of anodic aluminum oxide(AAO)film was transferred on the Si substrate by chemical method,and then a layer of SiC was deposited on anodic aluminum oxide(AAO)template to prepare porous fluorescent SiC film by magnetron sputtering.The deposition temperature was ranged from 373 to 873 K.The thickness of the porous SiC film coated on the AAO surface was around 283 nm.It is found that the porous SiC with the deposition temperature of 873 K has the strongest photoluminescence(PL)intensity excited by 375 nm laser.The time-resolved PL spectra prove that the PL is mainly from intrinsic light emitting of SiC.With the optimized process,porous amorphous SiC film may have potential applications in the field of warm white LEDs.展开更多
BACKGROUND Malancao(MLC)is a traditional Chinese medicine with a long history of utilization in treating ulcerative colitis(UC).Nevertheless,the precise molecular mechanisms underlying its efficacy remain elusive.This...BACKGROUND Malancao(MLC)is a traditional Chinese medicine with a long history of utilization in treating ulcerative colitis(UC).Nevertheless,the precise molecular mechanisms underlying its efficacy remain elusive.This study leveraged ultrahigh-performance liquid chromatography coupled with exactive mass spectrometry(UHPLC-QE-MS),network pharmacology,molecular docking(MD),and gene microarray analysis to discern the bioactive constituents and the potential mechanism of action of MLC in UC management.AIM To determine the ingredients related to MLC for treatment of UC using multiple databases to obtain potential targets for fishing.METHODS This research employs UHPLC-QE-MS for the identification of bioactive compounds present in MLC plant samples.Furthermore,the study integrates the identified MLC compound-related targets with publicly available databases to elucidate common drug disease targets.Additionally,the R programming language is utilized to predict the central targets and molecular pathways that MLC may impact in the treatment of UC.Finally,MD are conducted using AutoDock Vina software to assess the affinity of bioactive components to the main targets and confirm their therapeutic potential.RESULTS Firstly,through a comprehensive analysis of UHPLC-QE-MS data and public database resources,we identified 146 drug-disease cross targets related to 11 bioactive components.The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis highlighted that common disease drug targets are primarily involved in oxidative stress management,lipid metabolism,atherosclerosis,and other processes.They also affect AGE-RAGE and apoptosis signaling pathways.Secondly,by analyzing the differences in diseases,we identified key research targets.These core targets are related to 11 active substances,including active ingredients such as quercetin and luteolin.Finally,MD analysis revealed the stability of compound-protein binding,particularly between JUNLuteolin,JUN-Quercetin,HSP90AA1-Wogonin,and HSP90AA1-Rhein.Therefore,this suggests that MLC may help alleviate intestinal inflammation in UC,restore abnormal lipid accumulation,and regulate the expression levels of core proteins in the intestine.CONCLUSION The utilization of MLC has demonstrated notable therapeutic efficacy in the management of UC by means of the compound target interaction pathway.The amalgamation of botanical resources,metabolomics,natural products,MD,and gene chip technology presents a propitious methodology for investigating therapeutic targets of herbal medicines and discerning novel bioactive constituents.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11304157,21303255 and 11475229the‘Six Talent Peaks’Project in Jiangsu Province under Grant No 2015-JNHB-011the College Students Practice Innovative Training Program of Nuist under Grant No 201610300042
文摘Ultrafast dissociation dynamics of chloroiodomethane （CH2ICl） in the B band is studied by femtosecond time- resolved time-of-flight （TOF） mass spectrometry. Time-resolved TOF mass signal of parent ion （CH2ICl＋） and main daughter ion （CH2Cl＋） are obtained. The curve for the transient signal of CH2ICl＋ is simple and can be well fitted by an exponential decay convoluted with a Gaussian function. The decay constant determined to be less than 35 fs reflects the lifetime of the B band. Significant substituent effects on photodissociation dynamics of CH2IC1 compared with CH3I are discussed. The dissociation time from the parent ion CH2IC1＋ to the daughter ion CH2Cl＋ is determined in the experiment. The optimized geometry of the ionic state of CH2ICl and the ionization energy are calculated for further analysis of the measurements. In addition, compared with the parent ion, a new decay component with time constant of -596 fs is observed for CH2Cl＋, and reasonable mechanisms are proposed for the explanation.
基金Project supported by the National Natural Science Foundation of China(Grant No.60627003)the Foundation for Creative Team in Institution of Higher Education of Guangdong Province,China(Grant No.06CXTD009)
文摘In broadband coherent anti-Stokes Raman scattering （CARS） spectroscopy with supercontinuum （SC）, the simultaneously detectable spectral coverage is limited by the spectral continuity and the simultaneity of various spectral components of SC in an enough bandwidth. By numerical simulations, the optimal experimental conditions for improving the SC are obtained. The broadband time-resolved CARS spectrography based on the SC with required temporal and spectral distributions is realised. The global molecular vibrational spectrum with well suppressed nonresonant background noise can be obtained in a single measurement. At the same time, the measurements of dephasing times of various molecular vibrational modes can be conveniently achieved from intensities of a sequence of time-resolved CARS signals. It will be more helpful to provide a complete picture of molecular vibrations, and to exhibit a potential to understand not only both the solvent dynamics and the solute-solvent interactions, but also the mechanisms of chemical reactions in the fields of biology, chemistry and material science.
基金supported by the National Natural Science Funds of China(Grant No.81703664)Science and Technology Funds of Lanzhou,China(Grant No.201603111)
文摘The traditional Chinese medicine of Radix Hedysari plays an important role in invigorating gas for ascending, benefiting blood for promoting production of fluid, and promoting circulation for removing obstruction in collaterals, which is consistent with the principle of treatment for osteoporosis. This study is designed to investigate the bioactive components on increasing peak bone mass (PBM) by exploring the spectrum-effect relationship between chromatography fingerprints and effect. Multiple indicators are selected to evaluate the pharmacological activity. In fingerprints, 21 common peaks are obtained, five of which are identified. Furthermore, gray relational analysis (GRA) is a quantitative method of gray system theory and is used to describe the correlation degree of common peaks and pharmacological activities with relational value. 21 components are then divided into three different regions, of which ononin and calycosin play an extremely significant role in increasing PBM. In addition, factor analysis and hierarchical cluster analysis (HCA) are used to screen the optimal producing area for Radix Hedysari. This provides a comprehensive and efficient method to improve the quality evaluation of Radix Hedysari, confirming the bioactive components for PBM-enhancement and further develop its medicinal value.
文摘Dependence of decamethylcyclopentasiloxane （DMCPS） organosilicon dissociation on ionized energy in the energy range of 25 eV to 70 eV is investigated by using a quadrupole mass spectrometry. At the ionized energy below 55 eV, the dissociation of DMCPS is dominant. As the ionized energy is above 55 eV, the DMCPS dissociation achieves the maximum cross section, while the fragments from the DMCPS dissociation can further dissociate, which leads to a different ingredient of fragments. At the lower ionized energy of 25 eV, the main fragments are SiOC2H＋, SiCH＋, Si＋, O＋ and CH＋ ions, which shows an important effect on the SiCOH low-k film deposition.
文摘Based on the meson-meson mixing and Regge trajectory, this paper establishes the mass relations which can describe the mass spectrum of 1^1 P1 meson state. Using these mass relations, it obtains the mass of K1B, hi （1380） and hc（1P） to be 1358.5MeV, 1468 MeV and 3543.9 MeV, respectively. The results are compared with other theoretical results and should be tested by experiments in the future.
基金This work was supported by the National Natural Science Foundation of China(No.21833003 and No.21773213)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB17000000)Chinese Academy of Sciences(GJJSTD20190002).
文摘N-ethylpyrrole is one of ethylsubstituted derivatives of pyrrole and its excited-state decay dynamics has never been explored.In this work,we investigate ultrafast decay dynamics of N-ethylpyrrole excited to the S_(1)electronic state using a femtosecond time-resolved photoelectron imaging method.Two pump wavelengths of 241.9 and 237.7 nm are employed.At 241.9 nm,three time constants,5.0±0.7 ps,66.4±15.6 ps and 1.3±0.1 ns,are derived.For 237.7 nm,two time constants of 2.1±0.1 ps and 13.1±1.2 ps are derived.We assign all these time constants to be associated with different vibrational states in the S_(1)state.The possible decay mechanisms of different S_(1)vibrational states are briefly discussed.
文摘Based on the mechanism for mass creation in the space-time with extradimensions proposed in our previous work, (arXiv: 1301.1405 [hep-th] 2013) we consider now the mass spectrum of vector bosons in extradimensions. It is shown that this spectrum is completely determined by some function of compactification length and closely related to the metric of extradimensions.
文摘In this paper, we solve the eigen solutions to the Dirac equation with local parabolic potential which is approximately equal to the short distance potential generated by spinor itself. The energy spectrum is quite different from that with Coulomb potential. The mass spectrum of some bary-ons is similar to this one. The angular momentum-mass relation is quite similar to the Regge trajectories. The parabolic potential has a structure of asymptotic freedom near the center and confinement at a large distance. So, the results imply that, the local parabolic potential may be more suitable for describing the nuclear potential. The procedure of solving can also be used for some other cases of Dirac equation with complicated potential.
基金Funded by the National Natural Science Foundation of China(No.11747133)the Fundamental Research Funds for the Central Universities(No.195209019)。
文摘To study the effect of different deposition temperatures on the optical properties of porous SiC films,single crystal Si was used as the substrate,a layer of anodic aluminum oxide(AAO)film was transferred on the Si substrate by chemical method,and then a layer of SiC was deposited on anodic aluminum oxide(AAO)template to prepare porous fluorescent SiC film by magnetron sputtering.The deposition temperature was ranged from 373 to 873 K.The thickness of the porous SiC film coated on the AAO surface was around 283 nm.It is found that the porous SiC with the deposition temperature of 873 K has the strongest photoluminescence(PL)intensity excited by 375 nm laser.The time-resolved PL spectra prove that the PL is mainly from intrinsic light emitting of SiC.With the optimized process,porous amorphous SiC film may have potential applications in the field of warm white LEDs.
基金Supported by The Chongqing Science and Health Joint Chinese Medicine Technology Innovation and Application Development Project,No.2022MSXM209.
文摘BACKGROUND Malancao(MLC)is a traditional Chinese medicine with a long history of utilization in treating ulcerative colitis(UC).Nevertheless,the precise molecular mechanisms underlying its efficacy remain elusive.This study leveraged ultrahigh-performance liquid chromatography coupled with exactive mass spectrometry(UHPLC-QE-MS),network pharmacology,molecular docking(MD),and gene microarray analysis to discern the bioactive constituents and the potential mechanism of action of MLC in UC management.AIM To determine the ingredients related to MLC for treatment of UC using multiple databases to obtain potential targets for fishing.METHODS This research employs UHPLC-QE-MS for the identification of bioactive compounds present in MLC plant samples.Furthermore,the study integrates the identified MLC compound-related targets with publicly available databases to elucidate common drug disease targets.Additionally,the R programming language is utilized to predict the central targets and molecular pathways that MLC may impact in the treatment of UC.Finally,MD are conducted using AutoDock Vina software to assess the affinity of bioactive components to the main targets and confirm their therapeutic potential.RESULTS Firstly,through a comprehensive analysis of UHPLC-QE-MS data and public database resources,we identified 146 drug-disease cross targets related to 11 bioactive components.The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis highlighted that common disease drug targets are primarily involved in oxidative stress management,lipid metabolism,atherosclerosis,and other processes.They also affect AGE-RAGE and apoptosis signaling pathways.Secondly,by analyzing the differences in diseases,we identified key research targets.These core targets are related to 11 active substances,including active ingredients such as quercetin and luteolin.Finally,MD analysis revealed the stability of compound-protein binding,particularly between JUNLuteolin,JUN-Quercetin,HSP90AA1-Wogonin,and HSP90AA1-Rhein.Therefore,this suggests that MLC may help alleviate intestinal inflammation in UC,restore abnormal lipid accumulation,and regulate the expression levels of core proteins in the intestine.CONCLUSION The utilization of MLC has demonstrated notable therapeutic efficacy in the management of UC by means of the compound target interaction pathway.The amalgamation of botanical resources,metabolomics,natural products,MD,and gene chip technology presents a propitious methodology for investigating therapeutic targets of herbal medicines and discerning novel bioactive constituents.
