Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution （QKD） system. A new idea is put up to desi...Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution （QKD） system. A new idea is put up to design a quick single-photon detector. This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes （APDs）. All of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal. The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector. The single-photon prompt detection can come true for high repetition-rate pulses. The applying of this detector will largely raise the code rate of the OKD. and boost the commercial use.展开更多
The electron correlation correction is known as the key that dominates the quantitativeaccuracy of the computational quantum chemistry. To search for a new way of lesstime-consuming to estimate the electron correlatio...The electron correlation correction is known as the key that dominates the quantitativeaccuracy of the computational quantum chemistry. To search for a new way of lesstime-consuming to estimate the electron correlation energies of large-size molecules,展开更多
For the recent twenty years, the ab initio method, being in the leading position in thecomputational quantum chemistry, has made great and convincing success in theprediction of molecular geometries and properties of ...For the recent twenty years, the ab initio method, being in the leading position in thecomputational quantum chemistry, has made great and convincing success in theprediction of molecular geometries and properties of one-electronic behavior. On theother hand,the energy accuracy it gives is not generally adequate because the molecularorbital theory excessively emphasizes the independence of the motion of the electrons展开更多
Based on the analytical expression of relativistic free energy for a weakly interacting Fermi gas in a weak magnetic field, by using the method of quantum statistics, the stability conditions of the system at both hig...Based on the analytical expression of relativistic free energy for a weakly interacting Fermi gas in a weak magnetic field, by using the method of quantum statistics, the stability conditions of the system at both high and low temperatures are given, and the effects of magnetic field and interparticle interactions on the stability of the system are analysed. It is shown that at high temperatures, the stability conditions of the system are completely the same, no matter whether it is the ultrarelativistic case or nonrelativistic case. At extremely low temperatures, the mechanical stability conditions of the system show a similar rule through a comparison between the ultrarelativistic case and nonrelativistic case. At the same time, thermal stability of a relativistic Bose gas in a weak magnetic field is discussed, and the influence of the effect of relativity on the thermal stability of the system is investigated.展开更多
We argue in this document that initial vacuum state values possibly responsible for GW generation in relic conditions in the initial onset of inflation may have a temporary un squeezed, possibly even coherent initial ...We argue in this document that initial vacuum state values possibly responsible for GW generation in relic conditions in the initial onset of inflation may have a temporary un squeezed, possibly even coherent initial value, which would permit in certain models classical coherent initial gravitational wave states. Furthermore, several arguments pro and con as to if or not initial relic GW should be high frequency will be presented. The existence of higher dimensions, in itself if the additional dimensions are small and compact will have no capacity to influence the frequency values of relic GW, as predicted by Giovanni, and others in 1995. Furthermore, to consider are the results of Sahoo, Mishra, and Pacif (2016) which via Bianchi universes, removes the necessity of an initial space-time singularity, which may have bearing on the issue of the degree of the initial coherent states, so postulated for gravitational waves, as is brought up in the conclusion.展开更多
MicroRNA-based gene silencing is a functional genomics tool for a wide range of eukaryotes. As a basis for broader application of virus-induced gene silencing (VIGS) to photosynthesis research, we employed a tobacco r...MicroRNA-based gene silencing is a functional genomics tool for a wide range of eukaryotes. As a basis for broader application of virus-induced gene silencing (VIGS) to photosynthesis research, we employed a tobacco rattle virus (TRV) vector to silence expression of the nuclear psbS gene in Nicotiana benthamiana. The 22-kiloDalton psbS protein is essential for xanthophyll- and H+-dependent thermal dissipation of excitation in higher plants widely known as nonphotochemical quenching (NPQ). Controls treated with the TRV-VIGS vector containing a bacterial chloramphenicol resistance gene as the silencing target were included to test for non-silencing effects of the viral vector system. PsbS protein was undetectable and both psbS mRNA transcript levels and NPQ capacity were dramatically reduced in new leaf tissue of VIGS-psbS plants only. Photosynthetic performance in TRV-VIGS-treated and uninfiltrated plants was assessed by application of CO2 exchange, chlorophyll fluorescence, and in vivo absorbance changes at 810 nm. TRV-VIGS caused a mild stress based on pigment content and light absorption characteristics in some cases. To assess transient complementation of NPQ, the endogenous psbS gene was silenced using only the transit sequence in the TRV vector followed by Agrobacterium-mediated transient expression of a modified gene consisting of an altered transit sequence fused to the native mature protein sequence. Nevertheless, NPQ in infused fully expanded leaves that expressed this re-introduced form was not fully restored indicating the possible importance of psbS incorporation prior to formation of grana stacks.展开更多
The paper dealt with quantum canonical ensembles by random walks, where state transitions are triggered by the connections between labels, not by elements, which are transferred. The balance conditions of such walks l...The paper dealt with quantum canonical ensembles by random walks, where state transitions are triggered by the connections between labels, not by elements, which are transferred. The balance conditions of such walks lead to emission rates of the labels. The labels with emission rates definitely lower than 1 are like modes. For labels with emission rates very close to 1, the quantum numbers are concentrated around a mean value. As an application I consider the role of the zero label in a quantum gas in equilibrium.展开更多
We continue to analyse the known law of adiabatic transformation for an ideal gas PV5/3=Constant, where P isthe pressure and V is the volume, and following the approach of non-relativistic quantum mechanics which we s...We continue to analyse the known law of adiabatic transformation for an ideal gas PV5/3=Constant, where P isthe pressure and V is the volume, and following the approach of non-relativistic quantum mechanics which we suggested in a previous work （Yarman et al. 2010 Int. J. Phys. Sci. 5 1524）. We explicitly determine the constant for the general parallelepiped geometry of a container. We also disclose how the quantum numbers associated with molecules of an ideal gas vary through an arbitrary adiabatic transformation. Physical implications of the results obtained are discussed.展开更多
We present a simple demonstration of the nonfeasibility of metal-insulator transition in an exactly two-dimensional （2D） system. The Hartree-Fock potential in the 3D system is suitably modified and presented for the...We present a simple demonstration of the nonfeasibility of metal-insulator transition in an exactly two-dimensional （2D） system. The Hartree-Fock potential in the 3D system is suitably modified and presented for the 2D case. The many body effects are included in the screening function, and binding energies of a donor are obtained as a function of impurity concentration so as to find out the possible way leading metal-insulator transition in the 2D system. While solving for the binding energy for a shallow donor in an isolated well of a GaAs/Ga1-x Als As superlattice system within the effective mass approximation, it leads to unphysical results for higher concentrations. It shows that the phase transition, the bound electron entering into the conduction band whereby （H）min=0, is not possible beyond this concentration. The results suggest thai a phase transition is impossible in 213 systems, supporting the scaling theory of localization. The results are compared with the existing data available and discussed in the light of existing literature.展开更多
By means of the transfer matrix technique, the electronic transport through a quantum waveguide in the presence of a magnetic obstacle is investigated theoretically. By comparing the calculated conductance spectra of ...By means of the transfer matrix technique, the electronic transport through a quantum waveguide in the presence of a magnetic obstacle is investigated theoretically. By comparing the calculated conductance spectra of the opposite spin electrons, we find that there exists a notable spin filtering window in the low energy region. Dependences of such a spin filtering window on the size, position and potential strength of the magnetic obstacle are studied in detail.展开更多
In the first step, the Ehrenfest reasoning concerning the adiabatic invariance of the angular orbital momentum is applied to the electron motion in the hydrogen atom. It is demonstrated that the time of the energy emi...In the first step, the Ehrenfest reasoning concerning the adiabatic invariance of the angular orbital momentum is applied to the electron motion in the hydrogen atom. It is demonstrated that the time of the energy emission from the quantum level n+1 to level n can be deduced from the orbital angular momentum examined in the hydrogen atom. This time is found precisely equal to the time interval dictated by the Joule-Lenz law governing the electron transition between the levels n+1 and n. In the next step, the mechanical parameters entering the quantum systems are applied in calculating the time intervals characteristic for the electron transitions. This concerns the neighbouring energy levels in the hydrogen atom as well as the Landau levels in the electron gas submitted to the action of a constant magnetic field.展开更多
We investigate the itinerant ferromagnetism in a dipolar Fermi atomic system with the anisotropic spin–orbit coupling(SOC),which is traditionally explored with isotropic contact interaction.We first study the ferroma...We investigate the itinerant ferromagnetism in a dipolar Fermi atomic system with the anisotropic spin–orbit coupling(SOC),which is traditionally explored with isotropic contact interaction.We first study the ferromagnetism transition boundaries and the properties of the ground states through the density and spin-flip distribution in momentum space,and we find that both the anisotropy and the magnitude of the SOC play an important role in this process.We propose a helpful scheme and a quantum control method which can be applied to conquering the difficulties of previous experimental observation of itinerant ferromagnetism.Our further study reveals that exotic Fermi surfaces and an abnormal phase region can exist in this system by controlling the anisotropy of SOC,which can provide constructive suggestions for the research and the application of a dipolar Fermi gas.Furthermore,we also calculate the ferromagnetism transition temperature and novel distributions in momentum space at finite temperature beyond the ground states from the perspective of experiment.展开更多
In the present work,a solution-based co-precipitation method has been adopted to synthesize pure and cobalt-doped ZnS quantum dots and characterized by XRD,SEM,TEM with EDX,FTIR and gas sensing properties.XRD analysis...In the present work,a solution-based co-precipitation method has been adopted to synthesize pure and cobalt-doped ZnS quantum dots and characterized by XRD,SEM,TEM with EDX,FTIR and gas sensing properties.XRD analysis has shown a single phase of ZnS quantum dots having a zinc blend structure.TEM and XRD line broadening indicated that the average crystallite size in the sample is in the range of 2 to 5 nm.SEM micrographs show spherical-shaped quantum dots.FTIR studies show that cobalt has been successfully doped into the ZnS cubic lattice.EDX spectra have analyzed the elemental presence in the samples and it is evident that the spectra confirmed the presence of cobalt(Co),zinc(Zn),oxygen(O),and sulphur(S)elements only and no other impurities are observed.The ZnS-based quantum dot sensors reveal high sensitivity towards 50 ppm of ammonia vapors at an operating temperature of 70℃.Hence,ZnS-based quantum dots can be a promising and quick traceable sensor towards ammonia sensing applications with good response and recovery time.展开更多
基金the National Natu-ral Science Foundation of China (No.60378011 and 60578043)the Beijing Municipal Education Com-mission (No.XK100130637).
文摘Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution （QKD） system. A new idea is put up to design a quick single-photon detector. This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes （APDs）. All of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal. The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector. The single-photon prompt detection can come true for high repetition-rate pulses. The applying of this detector will largely raise the code rate of the OKD. and boost the commercial use.
基金Project supported by the National Natural Science Foundation of Chinathe Special Science Foundation of the State Education Commission of China.
文摘The electron correlation correction is known as the key that dominates the quantitativeaccuracy of the computational quantum chemistry. To search for a new way of lesstime-consuming to estimate the electron correlation energies of large-size molecules,
基金National Natural Science Foundation of ChinaScience Foundation of Tsinghua University.
文摘For the recent twenty years, the ab initio method, being in the leading position in thecomputational quantum chemistry, has made great and convincing success in theprediction of molecular geometries and properties of one-electronic behavior. On theother hand,the energy accuracy it gives is not generally adequate because the molecularorbital theory excessively emphasizes the independence of the motion of the electrons
文摘Based on the analytical expression of relativistic free energy for a weakly interacting Fermi gas in a weak magnetic field, by using the method of quantum statistics, the stability conditions of the system at both high and low temperatures are given, and the effects of magnetic field and interparticle interactions on the stability of the system are analysed. It is shown that at high temperatures, the stability conditions of the system are completely the same, no matter whether it is the ultrarelativistic case or nonrelativistic case. At extremely low temperatures, the mechanical stability conditions of the system show a similar rule through a comparison between the ultrarelativistic case and nonrelativistic case. At the same time, thermal stability of a relativistic Bose gas in a weak magnetic field is discussed, and the influence of the effect of relativity on the thermal stability of the system is investigated.
文摘We argue in this document that initial vacuum state values possibly responsible for GW generation in relic conditions in the initial onset of inflation may have a temporary un squeezed, possibly even coherent initial value, which would permit in certain models classical coherent initial gravitational wave states. Furthermore, several arguments pro and con as to if or not initial relic GW should be high frequency will be presented. The existence of higher dimensions, in itself if the additional dimensions are small and compact will have no capacity to influence the frequency values of relic GW, as predicted by Giovanni, and others in 1995. Furthermore, to consider are the results of Sahoo, Mishra, and Pacif (2016) which via Bianchi universes, removes the necessity of an initial space-time singularity, which may have bearing on the issue of the degree of the initial coherent states, so postulated for gravitational waves, as is brought up in the conclusion.
文摘MicroRNA-based gene silencing is a functional genomics tool for a wide range of eukaryotes. As a basis for broader application of virus-induced gene silencing (VIGS) to photosynthesis research, we employed a tobacco rattle virus (TRV) vector to silence expression of the nuclear psbS gene in Nicotiana benthamiana. The 22-kiloDalton psbS protein is essential for xanthophyll- and H+-dependent thermal dissipation of excitation in higher plants widely known as nonphotochemical quenching (NPQ). Controls treated with the TRV-VIGS vector containing a bacterial chloramphenicol resistance gene as the silencing target were included to test for non-silencing effects of the viral vector system. PsbS protein was undetectable and both psbS mRNA transcript levels and NPQ capacity were dramatically reduced in new leaf tissue of VIGS-psbS plants only. Photosynthetic performance in TRV-VIGS-treated and uninfiltrated plants was assessed by application of CO2 exchange, chlorophyll fluorescence, and in vivo absorbance changes at 810 nm. TRV-VIGS caused a mild stress based on pigment content and light absorption characteristics in some cases. To assess transient complementation of NPQ, the endogenous psbS gene was silenced using only the transit sequence in the TRV vector followed by Agrobacterium-mediated transient expression of a modified gene consisting of an altered transit sequence fused to the native mature protein sequence. Nevertheless, NPQ in infused fully expanded leaves that expressed this re-introduced form was not fully restored indicating the possible importance of psbS incorporation prior to formation of grana stacks.
文摘The paper dealt with quantum canonical ensembles by random walks, where state transitions are triggered by the connections between labels, not by elements, which are transferred. The balance conditions of such walks lead to emission rates of the labels. The labels with emission rates definitely lower than 1 are like modes. For labels with emission rates very close to 1, the quantum numbers are concentrated around a mean value. As an application I consider the role of the zero label in a quantum gas in equilibrium.
文摘We continue to analyse the known law of adiabatic transformation for an ideal gas PV5/3=Constant, where P isthe pressure and V is the volume, and following the approach of non-relativistic quantum mechanics which we suggested in a previous work （Yarman et al. 2010 Int. J. Phys. Sci. 5 1524）. We explicitly determine the constant for the general parallelepiped geometry of a container. We also disclose how the quantum numbers associated with molecules of an ideal gas vary through an arbitrary adiabatic transformation. Physical implications of the results obtained are discussed.
文摘We present a simple demonstration of the nonfeasibility of metal-insulator transition in an exactly two-dimensional （2D） system. The Hartree-Fock potential in the 3D system is suitably modified and presented for the 2D case. The many body effects are included in the screening function, and binding energies of a donor are obtained as a function of impurity concentration so as to find out the possible way leading metal-insulator transition in the 2D system. While solving for the binding energy for a shallow donor in an isolated well of a GaAs/Ga1-x Als As superlattice system within the effective mass approximation, it leads to unphysical results for higher concentrations. It shows that the phase transition, the bound electron entering into the conduction band whereby （H）min=0, is not possible beyond this concentration. The results suggest thai a phase transition is impossible in 213 systems, supporting the scaling theory of localization. The results are compared with the existing data available and discussed in the light of existing literature.
文摘By means of the transfer matrix technique, the electronic transport through a quantum waveguide in the presence of a magnetic obstacle is investigated theoretically. By comparing the calculated conductance spectra of the opposite spin electrons, we find that there exists a notable spin filtering window in the low energy region. Dependences of such a spin filtering window on the size, position and potential strength of the magnetic obstacle are studied in detail.
文摘In the first step, the Ehrenfest reasoning concerning the adiabatic invariance of the angular orbital momentum is applied to the electron motion in the hydrogen atom. It is demonstrated that the time of the energy emission from the quantum level n+1 to level n can be deduced from the orbital angular momentum examined in the hydrogen atom. This time is found precisely equal to the time interval dictated by the Joule-Lenz law governing the electron transition between the levels n+1 and n. In the next step, the mechanical parameters entering the quantum systems are applied in calculating the time intervals characteristic for the electron transitions. This concerns the neighbouring energy levels in the hydrogen atom as well as the Landau levels in the electron gas submitted to the action of a constant magnetic field.
基金supported by the National Key R&D Program of China(Grant Nos.2021YFA1400900,2021YFA0718300,and 2021YFA1400243)the Key Scientific Research Project of colleges and Universities in Henan Province(Nos.20A140018 and 23A140001)+1 种基金the National Natural Science Foundatiion of China(Grant Nos.12074105,12074106,12074120,12247146,12104135,and 61835013)the Natural Science Foundation of Shanghai(Grant No.20ZR1418500).
文摘We investigate the itinerant ferromagnetism in a dipolar Fermi atomic system with the anisotropic spin–orbit coupling(SOC),which is traditionally explored with isotropic contact interaction.We first study the ferromagnetism transition boundaries and the properties of the ground states through the density and spin-flip distribution in momentum space,and we find that both the anisotropy and the magnitude of the SOC play an important role in this process.We propose a helpful scheme and a quantum control method which can be applied to conquering the difficulties of previous experimental observation of itinerant ferromagnetism.Our further study reveals that exotic Fermi surfaces and an abnormal phase region can exist in this system by controlling the anisotropy of SOC,which can provide constructive suggestions for the research and the application of a dipolar Fermi gas.Furthermore,we also calculate the ferromagnetism transition temperature and novel distributions in momentum space at finite temperature beyond the ground states from the perspective of experiment.
文摘In the present work,a solution-based co-precipitation method has been adopted to synthesize pure and cobalt-doped ZnS quantum dots and characterized by XRD,SEM,TEM with EDX,FTIR and gas sensing properties.XRD analysis has shown a single phase of ZnS quantum dots having a zinc blend structure.TEM and XRD line broadening indicated that the average crystallite size in the sample is in the range of 2 to 5 nm.SEM micrographs show spherical-shaped quantum dots.FTIR studies show that cobalt has been successfully doped into the ZnS cubic lattice.EDX spectra have analyzed the elemental presence in the samples and it is evident that the spectra confirmed the presence of cobalt(Co),zinc(Zn),oxygen(O),and sulphur(S)elements only and no other impurities are observed.The ZnS-based quantum dot sensors reveal high sensitivity towards 50 ppm of ammonia vapors at an operating temperature of 70℃.Hence,ZnS-based quantum dots can be a promising and quick traceable sensor towards ammonia sensing applications with good response and recovery time.
