In order to derive the linac photon spectrum accurately both the prior constrained model and the genetic algorithm GA are employed using the measured percentage depth dose PDD data and the Monte Carlo simulated monoen...In order to derive the linac photon spectrum accurately both the prior constrained model and the genetic algorithm GA are employed using the measured percentage depth dose PDD data and the Monte Carlo simulated monoenergetic PDDs where two steps are involved.First the spectrum is modeled as a prior analytical function with two parameters αand Ep optimized with the GA.Secondly the linac photon spectrum is modeled as a discretization constrained model optimized with the GA. The solved analytical function in the first step is used to generate initial solutions for the GA’s first run in this step.The method is applied to the Varian iX linear accelerator to derive the energy spectra of its 6 and 15 MV photon beams.The experimental results show that both the reconstructed spectrums and the derived PDDs with the proposed method are in good agreement with those calculated using the Monte Carlo simulation.展开更多
Origen2.1 is a widely used computer code for calculating the burnup, decay, and processing of radioactive materials. However, the nuclide library of Origen2.1 is used for existing reactors like pressurized water react...Origen2.1 is a widely used computer code for calculating the burnup, decay, and processing of radioactive materials. However, the nuclide library of Origen2.1 is used for existing reactors like pressurized water reactors. To calculate the photon spectrum released by the decay of spallation products, we have made specific libraries for the ADS tungsten spallation target, based on the results given by the FLUKA Monte Carlo code. All the data used to make the Origen2.1 libraries are obtained from Nuclear structure ＆ decay Data （NuDat2.6）. The accumulated activity of spallation products and the contribution of nuclides to photon emission are given in this paper.展开更多
The one-colour resonant two-photon ionization （R2PI） spectrum of the 1-fluoronaphthalene （1FN） dimer has been studied in the wavelength range of 304 to 322 nm by using a supersonic molecular beam and time-of-fligh...The one-colour resonant two-photon ionization （R2PI） spectrum of the 1-fluoronaphthalene （1FN） dimer has been studied in the wavelength range of 304 to 322 nm by using a supersonic molecular beam and time-of-flight mass spectrometry. Compared with the original band 00^0 （at 313.8 nm） of the S1 ← So transition of the 1FN monomer, a red-shifted band was observed in the 1FN dimer spectrum at about 315 nm with a relatively large linewidth, nearly 2 nm. Based on the consideration of inductive effect and ab initio calculations, this red-shifted band is assigned to the first electronic excited transition of the 1FN dimer. A possible geometric structure of the 1FN dimer is also obtained with calculations that the two 1FN molecules are combined through two hydrogen bonds which are formed between the hydrogen atom of a molecule and the fluorine atom of a neighbouring molecule. A time-dependent calculation was also carried out and the results are consistent with the experimental data.展开更多
We study the interaction of a multi-photon three-level atom with a single mode field in a cavity, taking explicitly into account the existence of forms of nonlinearities of both the field and the intensity-dependent a...We study the interaction of a multi-photon three-level atom with a single mode field in a cavity, taking explicitly into account the existence of forms of nonlinearities of both the field and the intensity-dependent atom-field coupling. The analytical forms of the emission spectrum is calculated using the dressed states of the system. The effects of photon multiplicities, mean photon number, detuning, Kerr-like medium and the intensity-dependent coupling functional on the emission spectrum are analyzed.展开更多
Two kinds of fabricated hollow-core photonic crystal fibres （HC-PCFs） arc studied using finite element method （FEM） because the structures of the fibres are special, Normalized transmission spectra and transverse ...Two kinds of fabricated hollow-core photonic crystal fibres （HC-PCFs） arc studied using finite element method （FEM） because the structures of the fibres are special, Normalized transmission spectra and transverse intensity distribution of the modes are calculated and measured. And the dispersion characteristics of these two kinds of HC- PCFs were analysed from 400 nm to 800 nm. Simulated and measured results show that the special structure could affect the properties of HC-PCFs, By comparing the simulated values with the measured results, it can be clarified that FEM is feasible and accurate for analysing photonic crystal fibres whose structures are irregular and complex.展开更多
Knowledge of the band gap and transmission and reflection spectrum of a photonic crystal is essential elements for their design. A graphical interface that quickly determines the banding pattern and spectrum based on ...Knowledge of the band gap and transmission and reflection spectrum of a photonic crystal is essential elements for their design. A graphical interface that quickly determines the banding pattern and spectrum based on the Plane Wave Method (PWM) and coupled modes method (CMM) respectively is created. It is used to explore the behavior of a Bragg structure with the ability to easily vary the important parameters such as refractive indices, number and thickness of layers.展开更多
We propose broad supercontinuum spectrum generating highly nonlinear photonic crystal fiber (HN-PCF) which can be used in ultrahigh- resolution optical coherence tomography and optical transmission systems. Using full...We propose broad supercontinuum spectrum generating highly nonlinear photonic crystal fiber (HN-PCF) which can be used in ultrahigh- resolution optical coherence tomography and optical transmission systems. Using full vector finite difference method, we investigated the different properties of HN-PCF. Broadband su-percontinuum spectrum is numerically calculated by using nonlinear Schr?dinger equation. Investigation showed that it is possible to obtain longitudinal resolution in a biological tissue of 1.3 μm, 1.2 μm and 1.1 μm by using picosecond continuum light at center wavelengths of 1.06 μm, 1.31 μm and 1.55 μm, respectively.展开更多
The specific diameter of microtubules was shown to be a primary solution when magnetic energy was set equal to Casimir energy. To discern if this spatial containment could be foci for information photon emissions were...The specific diameter of microtubules was shown to be a primary solution when magnetic energy was set equal to Casimir energy. To discern if this spatial containment could be foci for information photon emissions were measured from preparations of microtubules (MTs) while they were exposed in sequential 4 min intervals to various patterns of weak magnetic fields whose intensities ranged from 3 to 10 μT. Calculations from the median mass of a tubulin dimer, its summed charges and the applied magnetic field as well as the change in magnetic moment derived from the energy of the hydrogen line when applied to our experimental fields predicted a dynamic shift (Δf) between 0.03 and 0.21 Hz. Spectral power densities (SPD) indicated marked enhancements in photon numbers during periods of magnetic field exposures within the 7.6 to 7.8 Hz increment. The total SPD units for the shift were 10-18 to 10-17 J per s. Five of the eight patterns elicited a split spectrum of power within this range. Separate factor analyses of the SPDs of the serial values that composed the points of the actual field patterns indicated those that evoked the split-spectrum (Δf = 0.05 to 0.13 Hz) displayed significantly higher loadings on the same factor compared to those that did not. If this shift in photon energy reflects a phase modulation of the coherence frequency (8 MHz) of MTs, the increment of energy per MHz frequency would be within the energy of the neutral hydrogen line. These results suggest that the intrinsic structure or information from specific intensity magnetic fields when applied to MTs is reflected in photon energy densities vacillating around the fundamental Schumann Resonance that could be an interface between Casimir and magnetic sources.展开更多
文摘In order to derive the linac photon spectrum accurately both the prior constrained model and the genetic algorithm GA are employed using the measured percentage depth dose PDD data and the Monte Carlo simulated monoenergetic PDDs where two steps are involved.First the spectrum is modeled as a prior analytical function with two parameters αand Ep optimized with the GA.Secondly the linac photon spectrum is modeled as a discretization constrained model optimized with the GA. The solved analytical function in the first step is used to generate initial solutions for the GA’s first run in this step.The method is applied to the Varian iX linear accelerator to derive the energy spectra of its 6 and 15 MV photon beams.The experimental results show that both the reconstructed spectrums and the derived PDDs with the proposed method are in good agreement with those calculated using the Monte Carlo simulation.
基金Supported by Strategic Priority Research Program of Chinese Academy of Sciences(XDA03030102)
文摘Origen2.1 is a widely used computer code for calculating the burnup, decay, and processing of radioactive materials. However, the nuclide library of Origen2.1 is used for existing reactors like pressurized water reactors. To calculate the photon spectrum released by the decay of spallation products, we have made specific libraries for the ADS tungsten spallation target, based on the results given by the FLUKA Monte Carlo code. All the data used to make the Origen2.1 libraries are obtained from Nuclear structure ＆ decay Data （NuDat2.6）. The accumulated activity of spallation products and the contribution of nuclides to photon emission are given in this paper.
基金supported by the Doctoral Special Fund of Qufu Normal University of China
文摘The one-colour resonant two-photon ionization （R2PI） spectrum of the 1-fluoronaphthalene （1FN） dimer has been studied in the wavelength range of 304 to 322 nm by using a supersonic molecular beam and time-of-flight mass spectrometry. Compared with the original band 00^0 （at 313.8 nm） of the S1 ← So transition of the 1FN monomer, a red-shifted band was observed in the 1FN dimer spectrum at about 315 nm with a relatively large linewidth, nearly 2 nm. Based on the consideration of inductive effect and ab initio calculations, this red-shifted band is assigned to the first electronic excited transition of the 1FN dimer. A possible geometric structure of the 1FN dimer is also obtained with calculations that the two 1FN molecules are combined through two hydrogen bonds which are formed between the hydrogen atom of a molecule and the fluorine atom of a neighbouring molecule. A time-dependent calculation was also carried out and the results are consistent with the experimental data.
文摘We study the interaction of a multi-photon three-level atom with a single mode field in a cavity, taking explicitly into account the existence of forms of nonlinearities of both the field and the intensity-dependent atom-field coupling. The analytical forms of the emission spectrum is calculated using the dressed states of the system. The effects of photon multiplicities, mean photon number, detuning, Kerr-like medium and the intensity-dependent coupling functional on the emission spectrum are analyzed.
基金Project supported by the State Key Development Program for Basic Research of China (Grant No 2003CB314905)the National High Technology Development Program of China (Grant No 2003AA311010)
文摘Two kinds of fabricated hollow-core photonic crystal fibres （HC-PCFs） arc studied using finite element method （FEM） because the structures of the fibres are special, Normalized transmission spectra and transverse intensity distribution of the modes are calculated and measured. And the dispersion characteristics of these two kinds of HC- PCFs were analysed from 400 nm to 800 nm. Simulated and measured results show that the special structure could affect the properties of HC-PCFs, By comparing the simulated values with the measured results, it can be clarified that FEM is feasible and accurate for analysing photonic crystal fibres whose structures are irregular and complex.
文摘Knowledge of the band gap and transmission and reflection spectrum of a photonic crystal is essential elements for their design. A graphical interface that quickly determines the banding pattern and spectrum based on the Plane Wave Method (PWM) and coupled modes method (CMM) respectively is created. It is used to explore the behavior of a Bragg structure with the ability to easily vary the important parameters such as refractive indices, number and thickness of layers.
文摘We propose broad supercontinuum spectrum generating highly nonlinear photonic crystal fiber (HN-PCF) which can be used in ultrahigh- resolution optical coherence tomography and optical transmission systems. Using full vector finite difference method, we investigated the different properties of HN-PCF. Broadband su-percontinuum spectrum is numerically calculated by using nonlinear Schr?dinger equation. Investigation showed that it is possible to obtain longitudinal resolution in a biological tissue of 1.3 μm, 1.2 μm and 1.1 μm by using picosecond continuum light at center wavelengths of 1.06 μm, 1.31 μm and 1.55 μm, respectively.
文摘The specific diameter of microtubules was shown to be a primary solution when magnetic energy was set equal to Casimir energy. To discern if this spatial containment could be foci for information photon emissions were measured from preparations of microtubules (MTs) while they were exposed in sequential 4 min intervals to various patterns of weak magnetic fields whose intensities ranged from 3 to 10 μT. Calculations from the median mass of a tubulin dimer, its summed charges and the applied magnetic field as well as the change in magnetic moment derived from the energy of the hydrogen line when applied to our experimental fields predicted a dynamic shift (Δf) between 0.03 and 0.21 Hz. Spectral power densities (SPD) indicated marked enhancements in photon numbers during periods of magnetic field exposures within the 7.6 to 7.8 Hz increment. The total SPD units for the shift were 10-18 to 10-17 J per s. Five of the eight patterns elicited a split spectrum of power within this range. Separate factor analyses of the SPDs of the serial values that composed the points of the actual field patterns indicated those that evoked the split-spectrum (Δf = 0.05 to 0.13 Hz) displayed significantly higher loadings on the same factor compared to those that did not. If this shift in photon energy reflects a phase modulation of the coherence frequency (8 MHz) of MTs, the increment of energy per MHz frequency would be within the energy of the neutral hydrogen line. These results suggest that the intrinsic structure or information from specific intensity magnetic fields when applied to MTs is reflected in photon energy densities vacillating around the fundamental Schumann Resonance that could be an interface between Casimir and magnetic sources.
