In order to achieve a wider range of ionizing radiations detection,novel fluorescence sensing materials have been developed that utilize the fluorescence enhancement phenomenon caused by the intramolecular photoinduce...In order to achieve a wider range of ionizing radiations detection,novel fluorescence sensing materials have been developed that utilize the fluorescence enhancement phenomenon caused by the intramolecular photoinduced electron transfer(PET)effect.Two perylene diimide isomers PDI-P and PDI-B were designed and synthesized,and their molecular structures were characterized by high-resolution Fourier transform mass spectrometry(HRMS),nuclear magnetic resonance hydrogen and carbon spectroscopy(~1H and~(13)C NMR).The interaction between ionizing radiation and fluorescent molecules was simulated by HCl titration.The results show that combining PDIs and HCl can improve fluorescence through the retro-PET process.Despite the similarities in chemical structures,the fluorescent enhancement multiple of PDI-B with aromatic amine as electron donor is much higher than that of PDI-P with alkyl amine.In the direct irradiation experiments of ionizing radiation,the emission enhancement multiples of PDI-P and PDI-B are 2.01 and 45.4,respectively.Furthermore,density functional theory(DFT)and time-dependent density functional theory(TDDFT)calculations indicate that the HOMO and HOMO-1 energy ranges of PDI-P and PDI-B are 0.54 e V and 1.13 e V,respectively.A wider energy range has a stronger driving force on electrons,which is conducive to fluorescence quenching.Both femtosecond transient absorption spectroscopy(fs-TAS)and transient fluorescence spectroscopy(TFS)tests show that PDI-B has shorter charge separation lifetime and higher electron transfer rate constant.Although both isomers can significantly reduce LOD during PET process,PDI-B with aromatic amine has a wider detection range of 0.118—240 Gy due to its larger emission enhancement,which is a leap of three orders of magnitude.It breaks through the detection range of gamma radiation reported in existing studies,and provides theoretical support for the further study of sensitive and effective new materials for ionizing radiation detection.展开更多
The brain of humans and other organisms is affected in various ways through the electromagneticfield(EMF)radiations generated by mobile phones and cell phone towers.Morphological variations in the brain are caused by t...The brain of humans and other organisms is affected in various ways through the electromagneticfield(EMF)radiations generated by mobile phones and cell phone towers.Morphological variations in the brain are caused by the neurological changes due to the revelation of EMF.Cellular level analysis is used to measure and detect the effect of mobile radiations,but its utilization seems very expensive,and it is a tedious process,where its analysis requires the preparation of cell suspension.In this regard,this research article proposes optimal broadcast-ing learning to detect changes in brain morphology due to the revelation of EMF.Here,Drosophila melanogaster acts as a specimen under the revelation of EMF.Automatic segmentation is performed for the brain to attain the microscopic images from the prejudicial geometrical characteristics that are removed to detect the effect of revelation of EMF.The geometrical characteristics of the brain image of that is microscopic segmented are analyzed.Analysis results reveal the occur-rence of several prejudicial characteristics that can be processed by machine learn-ing techniques.The important prejudicial characteristics are given to four varieties of classifiers such as naïve Bayes,artificial neural network,support vector machine,and unsystematic forest for the classification of open or nonopen micro-scopic image of D.melanogaster brain.The results are attained through various experimental evaluations,and the said classifiers perform well by achieving 96.44%using the prejudicial characteristics chosen by the feature selection meth-od.The proposed system is an optimal approach that automatically identifies the effect of revelation of EMF with minimal time complexity,where the machine learning techniques produce an effective framework for image processing.展开更多
Human beings have continually been exposed to radiation from sources that are terrestrial. There are different sources of radiation for instance ubiquitous background and medical exams that require X-rays. In America ...Human beings have continually been exposed to radiation from sources that are terrestrial. There are different sources of radiation for instance ubiquitous background and medical exams that require X-rays. In America for example, the rate of radiation intake per individual increased from 1.6 to 6.2 mSv. The increase has been associated with increased imaging procedures in healthcare facilities. The continued exposure of people to radiant’s increases their rates of developing cardiovascular related diseases. A person who is exposed to low amounts of radiation over a long duration may in the long run develop heart diseases. The result has been obtained from an experiment with the Japanese survivors of the atomic bomb. This research paper focuses on the different sources of radiations and the risk of contracting cardiovascular diseases. The paper also explains the possible relationship between radiations and cardiovascular diseases.展开更多
A unified analysis is presented to calculate the incoherent spontaneous power of cooperative radiations based on self-amplified spontaneous emission. Using quantum mechanical tools, we derive analytical expressions fo...A unified analysis is presented to calculate the incoherent spontaneous power of cooperative radiations based on self-amplified spontaneous emission. Using quantum mechanical tools, we derive analytical expressions for the incoherent spontaneous power of undulator and Cherenkov free-electron lasers (FELs). The undulator and Cherenkov FELs are considered as two different examples for the radiation that accumulate cooperatively. In the case of the undulator FEL, we show an excellent agreement between an expression for the incoherent radiation power derived in the present work and that obtained using a completely different approach [Phys. Ftev. E 65 (2002) 026501]. For the Cherenkov radiation, we demonstrate a satisfactory agreement between the incoherent power predicted in our analysis and previous experimental results.展开更多
Surveying ionizing radiations of the surrounding with a smartphone provides a low-cost and convenient utility for the general public. We developed a smartphone application(App) that uses the built-in camera with a CMO...Surveying ionizing radiations of the surrounding with a smartphone provides a low-cost and convenient utility for the general public. We developed a smartphone application(App) that uses the built-in camera with a CMOS sensor and a radiation signal extraction algorithm.After a calibration through a series of radiation exposures,the App could display radiation dose rate and cumulative dose in real time without requiring covering the camera lens. A smartphone with this App can be used as a fast survey tool for ionizing radiations.展开更多
The monthly extraterrestrial solar radiations (ESR) have been simulated separately for all the months of the year. The subtropical location and distribution of mountains and their height determine the spatial distribu...The monthly extraterrestrial solar radiations (ESR) have been simulated separately for all the months of the year. The subtropical location and distribution of mountains and their height determine the spatial distribution and amount of ESR in Pakistan. The mountains, piedmonts, enclosed valleys and plains show distinct diversity of ESR values. The assessment acknowledged that countries like Pakistan with ever increasing demand of energy receive sufficient amount of ESR that could be linked with solar irradiance where development of solar energy has great potential. The simulation was done with the help of ArcGIS based on distributed modeling.展开更多
The present study deals with the flow over a nonlinearly stretching sheet of Casson fluid with the effects of radiation and heat source/sink. The Casson fluid model is used to characterize the non-Newtonian fluid beha...The present study deals with the flow over a nonlinearly stretching sheet of Casson fluid with the effects of radiation and heat source/sink. The Casson fluid model is used to characterize the non-Newtonian fluid behaviour. With the help of justified similarity transformations the governing equations were reduced to couple nonlinear ordinary differential equations. The effective numerical technique Keller Box method is used to solve these equations. The variations in velocity, temperature profiles were presented with the various values of nonlinear stretching parameter n and Casson parameter β. The nature of Skinfriction and Local nusselt number has presented. Effects of radiation and heat source/sink on temperature profiles have been discussed.展开更多
Miniature roses (Rosa sp.) and Kalanchoe blossfeldiana were grown at photon flux densities (PFD) ranging from 60 to 670 μmol·m-2·s-1 (associated with a temperature gradient from 20.0°C to 24.0°C [...Miniature roses (Rosa sp.) and Kalanchoe blossfeldiana were grown at photon flux densities (PFD) ranging from 60 to 670 μmol·m-2·s-1 (associated with a temperature gradient from 20.0°C to 24.0°C [TEMP1]) and from 50 to 370μmol·m-2-s-1 (associated with a temperature gradient from 22.5°C to 26.5°C [TEMP2]). The experiment was conducted in a greenhouse compartment at latitude 59° north in mid-winter. The daily photosynthetic active radiations (PAR) ranged from 4.3 to 48.2 and 3.6 to 26.6 mol·m-2·day-1 in the TEMP1 and TEMP2 treatments, respectively. Time until flowering in miniature roses decreased from about 50 to 35 days in the TEMP1 treatment and from 50 to 25 days in the TEMP2 treatment, when the PFD increased from 50 to 370μmol·m-2·s-1. In Kalanchoe time until flowering was decreased to the same extent (about 15 days) in both temperature treatments when PFD increased from 50 to 370 μmol·m-2·s-1. The number of flowers and the plant dry weight in miniature roses increased up to 300 – 400 μmol·m-2·s-1 PFD (21.6 - 28.8 mol·m-2 day-1 PAR), while flower stem fresh weight and plant dry weight in Kalanchoe increased up to 200 – 300 μmol·m-2·s-1 at TEMP1. Measurements of the diurnal carbon dioxide exchange rates (CER) in daylight in small plant stands of roses in summertime showed that CER was saturated at about 300 μmol·m-2·s-1 PFD at 370 μmol·mol-1 CO2 and at 400 – 500 μmol·m-2·s-1 PFD at 800 μmol·mol-1 CO2. For Kalanchoe similar results were obtained. Increasing the CO2 concentration from 370 to 800 μmol·mol-1 increased the CER in roses (48%) as well in Kalanchoe (69%). It was concluded that 15 to 20 mol·m-2·day-1 combined with about 24°C air temperature and high CO2 concentration will give a very good growth with lot of flowers within a short production time in miniature roses. For Kalanchoe 10 to 15 mol·m-2·day-1 combined with about 20°C and high CO2 produced a similar result.展开更多
In this paper, it is shown that the laser radiation intensity required for complete ionization of vapors produced on an irradiated metal surface can be reduced by more than an order of magnitude through using pulsed l...In this paper, it is shown that the laser radiation intensity required for complete ionization of vapors produced on an irradiated metal surface can be reduced by more than an order of magnitude through using pulsed laser radiation in combination with microwave radiation.展开更多
Objective: To study the protective effect of ascorbic acid and curcumin against the abnormal estrous cycle and morphological changes in cells induced by repeated ultraviolet B(UVB)radiation in female Wistar rats.Metho...Objective: To study the protective effect of ascorbic acid and curcumin against the abnormal estrous cycle and morphological changes in cells induced by repeated ultraviolet B(UVB)radiation in female Wistar rats.Methods: Sixteen female sexually mature Wistar rats weighing 130-150 g and aged 12-16 weeks were randomly divided into four groups.The control group received normal food and water ad libitum.The UVB group was exposed to a dose of 280 nm of UVB radiation for 2 h daily.The UVB+curcumin group received a dose of 280 nm of UVB radiation for 2 h daily and also an oral dose of curcumin(25 mg/kg body weight)daily.The UVB+ascorbic acid group received a dose of 280 nm of UVB radiation for 2 h daily and also an oral dose of ascorbic acid(250 mg/kg body weight)daily.All the treatments last for 15 consecutive days.Body and ovary weight and gonadosomatic index were measured.The stages(proestrus,estrus,metaestrus and diestrus)of the estrous cycle were determined by the cell types observed in the vaginal smear.Results: UVB radiation caused irregular alterations on the estrous cycle and morphological changes of the female Wistar rat as compared with the control group.Ascorbic acid and curcumin protected UVB-induced estrous phases and their cells.But curcumin showed greater protection than ascorbic acid.Conclusions: Ascorbic acid and curcumin at low doses can alleviate abnormal estrous cycle and morphological changes in cells induced by UVB radiations in female Wistar rats.展开更多
An explanation is given for the thermal equilibrium in the biosphere, which is based in the equality between the thermal energy received from the sun and the thermal energy reemitted from the atmosphere to the space. ...An explanation is given for the thermal equilibrium in the biosphere, which is based in the equality between the thermal energy received from the sun and the thermal energy reemitted from the atmosphere to the space. In order to understand the origin of the energy that gives rise to the processes and phenomena taking place in the biosphere, it is necessary to take into account the free energy represented by the product of temperature times the change in entropy, T△S, whose magnitude can be attributed to the variation experimented by the wavelengths (or, consequently, the frequencies) of the radiations composing the radiation spectrum received from the sun compared with the radiation spectrum reemitted from the biosphere into the space. A simple discussion allows to predict that the entropy increase driving the processes is connected with a spontaneous conversion of high frequency radiations (with lower “content” of entropy) in radiations of lower frequencies (with higher “content” of entropy). A consequence of this is that high frequency radiations would correspond to more ordered states and, therefore, to less probable states than those corresponding to radiations of lower frequencies.展开更多
The transverse magnetic (TM) radiation characteristics are investigated for a cylinder with N infinite axial slots of arbitrary opening size and location. The cylinder is a thin circular conductor and coated by an ecc...The transverse magnetic (TM) radiation characteristics are investigated for a cylinder with N infinite axial slots of arbitrary opening size and location. The cylinder is a thin circular conductor and coated by an eccentric material. Fields are found by applying the boundary conditions to the cylindrical wave functions. The addition theorem of Bessel functions is used to obtain an infinite series solution in Fourier–Bessel series form. Results are computed by shrinking the generated infinite series to a finite number of terms and compared to other available data. Numerical results in graphical forms for different values are also developed and discussed for small eccentricities.展开更多
In this study, we simulated space flight of the nematode, Caenorhabditis elegans, on the ground and examined how it is affected by space radiation and G-forces. We simulated G-forces during launch in a gravity acceler...In this study, we simulated space flight of the nematode, Caenorhabditis elegans, on the ground and examined how it is affected by space radiation and G-forces. We simulated G-forces during launch in a gravity acceleration laboratory device in order to identify and isolate the effects of the G-forces. Following this, we irradiated C. elegans with accelerated protons (MC-50 Cyclotron) and gamma rays (iR 222 machine) at the same physical dose. We calculated the expected radiation dose according to Reitz [1] and simulation programs (NASA AP8MIN [2], NASA AE8MAX [2], and CREAM86 [3]) for 1 month (dose rate: 6 × 10-3 Gy;2.8 × 10-2 Gy), 6 months (dose rate: 36 × 10-3 Gy;16.8 × 10-2 Gy), and 2 years (dose rate: 144 × 10-3 Gy;67.2 × 10-2 Gy) of space flight. There have been several trials that aimed to take C. elegans into orbit on US space shuttle missions including a mission on the shuttle Columbia. In this study, we simulated longer duration space flights and performed a whole-genome microarray analysis to observe phenotype variations whereas most such experiments were carried out during short duration space flights and focused on mutations and genotypic variations. We expect that the results of this study will be useful to predict the effects of long-term exposure of space radiation on living organisms.展开更多
The results of experimental research of some effects in metal-insulator-semiconductor (MIS) structures induced by different types of radiation (50 MeV electrons, 12 keV gamma-quanta, 10 and 40 keV arsenic ions) are pr...The results of experimental research of some effects in metal-insulator-semiconductor (MIS) structures induced by different types of radiation (50 MeV electrons, 12 keV gamma-quanta, 10 and 40 keV arsenic ions) are presented. It is found that there is a significant difference between the characters of radiation surface states (SS) formed by ionization and impact actions of the MIS structure irradiation at the insulator-semiconductor (I-S) interface. It is shown that the SS generation rate is increased in electric fields and depends on the MIS structure field electrode material.展开更多
We investigate the spatial dependence of high energy electrons and their radiations in pulsar wind nebulae (PWNe). By assuming a time-dependent broken power-law injection and spatial dependence of convection velocit...We investigate the spatial dependence of high energy electrons and their radiations in pulsar wind nebulae (PWNe). By assuming a time-dependent broken power-law injection and spatial dependence of convection velocity, magnetic field strength and diffusion coefficient on the radial distance of an expand- ing system, we numerically solve the Fokker-Planck transport equation including convection, diffusion, adiabatic loss and radiative loss in spherical coordinates, and investigate the effects of magnetic field, PWN age, maximum energy of electrons, and diffusion coefficient on electron spectra and non-thermal photon emissions. Our results indicate that (1) electron spectra and the corresponding photon spectra are a function of radial distance r of the expanding system; (2) for a given expansion velocity, the increase of the PWN age causes a slower decrease of the convection velocity (V ∝ r-β) and a more rapid decrease of the magnetic field strength (B ∝ r-1+β), but a more rapid increase of the diffusion coefficient (k∝ r1-β) because the index β decreases with the PWN age; and (3) the lower energy part of the electron spectra is dominated by convection and adiabatic loss, but the higher energy part is dominated by the competition between syn- chrotron loss and diffusion, and such a competition is a function of radial distance. Therefore the diffusion effect has an important role in the evolution of electron spectra as well as non-thermal photon spectra in a PWN.展开更多
Spores are the biological structures formed out of sporulation from vegetative cells in adverse conditions.Being tolerant to many extreme environment and conditions,they escape and survives critical processing steps i...Spores are the biological structures formed out of sporulation from vegetative cells in adverse conditions.Being tolerant to many extreme environment and conditions,they escape and survives critical processing steps in the food industry that poses food and health safety problems,as is evident from the increase in reports of food-bome outbreaks due to spore-fomers.Electromagnetic radiation(EM)is used for rapid decontamination and sterilization purposes in the food industry.Many studies have reported a greater reduction in spore population upon irradiation with EM rays due to its impact on genomic material and other components of spores that destabilises overall structue and brings clonogenic death However,there is scattered literature regarding the mechanism of its inactivation and resistance against such damage.This review attempts to concisely evaluate the potential of electromagnetic radiations in spore inactivation and details its mechanism through a collective study of scientific results and repouts.It also briefs about the process of sporulation,the structure of spores and the role of its components in the resistance of spores to damage.Many studies,which demonstrated that combining various EM treatments might be an effective way for inactivation of spores,were discussed in detail.展开更多
The ESA and CAS SMILE mission orbit is highly elliptical and will pass through multiple radiation environments.The Soft X-ray Imager(SXI)instrument aboard has a radiation shutter door designed to close when the surrou...The ESA and CAS SMILE mission orbit is highly elliptical and will pass through multiple radiation environments.The Soft X-ray Imager(SXI)instrument aboard has a radiation shutter door designed to close when the surrounding radiation flux is high.The shutter door will close when passing below an altitude threshold to protect against trapped particles in the Earth’s Van Allen Belts.Therefore,two radiation environments can be approximated based on the shutter door position:open and closed.The instrument background for the CCDs(Charge-Coupled Devices)that form the focal plane array of the SXI were evaluated for the two environments.Due to the correlation of the space environment with the solar cycle,the solar minima and maxima,the background was also evaluated at these two extremes.The results demonstrated that the highest instrument background will occur during solar minima due to the main contributing source being Galactic Cosmic Rays(GCRs).It was also found that the open background was highest for solar minima and that the closed background was highest during solar maxima.This is due to the radiation shutter door acting as a scattering centre and the changes in the energy flux distribution of the GCRs between the two solar extremes.展开更多
As interest in double perovskites is growing,especially in applications like photovoltaic devices,understanding their mechanical properties is vital for device durability.Despite extensive exploration of structure and...As interest in double perovskites is growing,especially in applications like photovoltaic devices,understanding their mechanical properties is vital for device durability.Despite extensive exploration of structure and optical properties,research on mechanical aspects is limited.This article builds a vacancyordered double perovskite model,employing first-principles calculations to analyze mechanical,bonding,electronic,and optical properties.Results show Cs_(2)Hfl_(6),Cs_(2)SnBr_(6),Cs_(2)SnI_(6),and Cs_(2)PtBr_(6)have Young's moduli below 13 GPa,indicating flexibility.Geometric parameters explain flexibility variations with the changes of B and X site composition.Bonding characteristic exploration reveals the influence of B and X site electronegativity on mechanical strength.Cs_(2)SnBr_(6)and Cs_(2)PtBr_(6)are suitable for solar cells,while Cs_(2)HfI_(6)and Cs_(2)TiCl_(6)show potential for semi-transparent solar cells.Optical property calculations highlight the high light absorption coefficients of up to 3.5×10^(5) cm^(-1)for Cs_(2)HfI_(6)and Cs_(2)TiCl_(6).Solar cell simulation shows Cs_(2)PtBr_(6)achieves 22.4%of conversion effciency.Cs_(2)ZrCl_(6)holds promise for ionizing radiation detection with its 3.68 eV bandgap and high absorption coefficient.Vacancy-ordered double perovskites offer superior flexibility,providing valuable insights for designing stable and flexible devices.This understanding enhances the development of functional devices based on these perovskites,especially for applications requiring high stability and flexibility.展开更多
基金financial support from the National Natural Science Foundation of China(Grant No.21801016)the Science and Technology on Applied Physical Chemistry Laboratory(Grant No.6142602220304)。
文摘In order to achieve a wider range of ionizing radiations detection,novel fluorescence sensing materials have been developed that utilize the fluorescence enhancement phenomenon caused by the intramolecular photoinduced electron transfer(PET)effect.Two perylene diimide isomers PDI-P and PDI-B were designed and synthesized,and their molecular structures were characterized by high-resolution Fourier transform mass spectrometry(HRMS),nuclear magnetic resonance hydrogen and carbon spectroscopy(~1H and~(13)C NMR).The interaction between ionizing radiation and fluorescent molecules was simulated by HCl titration.The results show that combining PDIs and HCl can improve fluorescence through the retro-PET process.Despite the similarities in chemical structures,the fluorescent enhancement multiple of PDI-B with aromatic amine as electron donor is much higher than that of PDI-P with alkyl amine.In the direct irradiation experiments of ionizing radiation,the emission enhancement multiples of PDI-P and PDI-B are 2.01 and 45.4,respectively.Furthermore,density functional theory(DFT)and time-dependent density functional theory(TDDFT)calculations indicate that the HOMO and HOMO-1 energy ranges of PDI-P and PDI-B are 0.54 e V and 1.13 e V,respectively.A wider energy range has a stronger driving force on electrons,which is conducive to fluorescence quenching.Both femtosecond transient absorption spectroscopy(fs-TAS)and transient fluorescence spectroscopy(TFS)tests show that PDI-B has shorter charge separation lifetime and higher electron transfer rate constant.Although both isomers can significantly reduce LOD during PET process,PDI-B with aromatic amine has a wider detection range of 0.118—240 Gy due to its larger emission enhancement,which is a leap of three orders of magnitude.It breaks through the detection range of gamma radiation reported in existing studies,and provides theoretical support for the further study of sensitive and effective new materials for ionizing radiation detection.
文摘The brain of humans and other organisms is affected in various ways through the electromagneticfield(EMF)radiations generated by mobile phones and cell phone towers.Morphological variations in the brain are caused by the neurological changes due to the revelation of EMF.Cellular level analysis is used to measure and detect the effect of mobile radiations,but its utilization seems very expensive,and it is a tedious process,where its analysis requires the preparation of cell suspension.In this regard,this research article proposes optimal broadcast-ing learning to detect changes in brain morphology due to the revelation of EMF.Here,Drosophila melanogaster acts as a specimen under the revelation of EMF.Automatic segmentation is performed for the brain to attain the microscopic images from the prejudicial geometrical characteristics that are removed to detect the effect of revelation of EMF.The geometrical characteristics of the brain image of that is microscopic segmented are analyzed.Analysis results reveal the occur-rence of several prejudicial characteristics that can be processed by machine learn-ing techniques.The important prejudicial characteristics are given to four varieties of classifiers such as naïve Bayes,artificial neural network,support vector machine,and unsystematic forest for the classification of open or nonopen micro-scopic image of D.melanogaster brain.The results are attained through various experimental evaluations,and the said classifiers perform well by achieving 96.44%using the prejudicial characteristics chosen by the feature selection meth-od.The proposed system is an optimal approach that automatically identifies the effect of revelation of EMF with minimal time complexity,where the machine learning techniques produce an effective framework for image processing.
文摘Human beings have continually been exposed to radiation from sources that are terrestrial. There are different sources of radiation for instance ubiquitous background and medical exams that require X-rays. In America for example, the rate of radiation intake per individual increased from 1.6 to 6.2 mSv. The increase has been associated with increased imaging procedures in healthcare facilities. The continued exposure of people to radiant’s increases their rates of developing cardiovascular related diseases. A person who is exposed to low amounts of radiation over a long duration may in the long run develop heart diseases. The result has been obtained from an experiment with the Japanese survivors of the atomic bomb. This research paper focuses on the different sources of radiations and the risk of contracting cardiovascular diseases. The paper also explains the possible relationship between radiations and cardiovascular diseases.
基金Supported by the ASRT-INFN Joint Project between the Academy of Scientific Research and Technology in Egypt and INFN in Italy
文摘A unified analysis is presented to calculate the incoherent spontaneous power of cooperative radiations based on self-amplified spontaneous emission. Using quantum mechanical tools, we derive analytical expressions for the incoherent spontaneous power of undulator and Cherenkov free-electron lasers (FELs). The undulator and Cherenkov FELs are considered as two different examples for the radiation that accumulate cooperatively. In the case of the undulator FEL, we show an excellent agreement between an expression for the incoherent radiation power derived in the present work and that obtained using a completely different approach [Phys. Ftev. E 65 (2002) 026501]. For the Cherenkov radiation, we demonstrate a satisfactory agreement between the incoherent power predicted in our analysis and previous experimental results.
基金supported in part by Fundamental Research Funds for the Central Universities(No.FRF-TP-15-114A1)the National Natural Science Foundation of China(No.11505300&11605008)
文摘Surveying ionizing radiations of the surrounding with a smartphone provides a low-cost and convenient utility for the general public. We developed a smartphone application(App) that uses the built-in camera with a CMOS sensor and a radiation signal extraction algorithm.After a calibration through a series of radiation exposures,the App could display radiation dose rate and cumulative dose in real time without requiring covering the camera lens. A smartphone with this App can be used as a fast survey tool for ionizing radiations.
文摘The monthly extraterrestrial solar radiations (ESR) have been simulated separately for all the months of the year. The subtropical location and distribution of mountains and their height determine the spatial distribution and amount of ESR in Pakistan. The mountains, piedmonts, enclosed valleys and plains show distinct diversity of ESR values. The assessment acknowledged that countries like Pakistan with ever increasing demand of energy receive sufficient amount of ESR that could be linked with solar irradiance where development of solar energy has great potential. The simulation was done with the help of ArcGIS based on distributed modeling.
文摘The present study deals with the flow over a nonlinearly stretching sheet of Casson fluid with the effects of radiation and heat source/sink. The Casson fluid model is used to characterize the non-Newtonian fluid behaviour. With the help of justified similarity transformations the governing equations were reduced to couple nonlinear ordinary differential equations. The effective numerical technique Keller Box method is used to solve these equations. The variations in velocity, temperature profiles were presented with the various values of nonlinear stretching parameter n and Casson parameter β. The nature of Skinfriction and Local nusselt number has presented. Effects of radiation and heat source/sink on temperature profiles have been discussed.
基金This work was funded by the Agricultural bank of Norway and the Norwegian Growers Association.
文摘Miniature roses (Rosa sp.) and Kalanchoe blossfeldiana were grown at photon flux densities (PFD) ranging from 60 to 670 μmol·m-2·s-1 (associated with a temperature gradient from 20.0°C to 24.0°C [TEMP1]) and from 50 to 370μmol·m-2-s-1 (associated with a temperature gradient from 22.5°C to 26.5°C [TEMP2]). The experiment was conducted in a greenhouse compartment at latitude 59° north in mid-winter. The daily photosynthetic active radiations (PAR) ranged from 4.3 to 48.2 and 3.6 to 26.6 mol·m-2·day-1 in the TEMP1 and TEMP2 treatments, respectively. Time until flowering in miniature roses decreased from about 50 to 35 days in the TEMP1 treatment and from 50 to 25 days in the TEMP2 treatment, when the PFD increased from 50 to 370μmol·m-2·s-1. In Kalanchoe time until flowering was decreased to the same extent (about 15 days) in both temperature treatments when PFD increased from 50 to 370 μmol·m-2·s-1. The number of flowers and the plant dry weight in miniature roses increased up to 300 – 400 μmol·m-2·s-1 PFD (21.6 - 28.8 mol·m-2 day-1 PAR), while flower stem fresh weight and plant dry weight in Kalanchoe increased up to 200 – 300 μmol·m-2·s-1 at TEMP1. Measurements of the diurnal carbon dioxide exchange rates (CER) in daylight in small plant stands of roses in summertime showed that CER was saturated at about 300 μmol·m-2·s-1 PFD at 370 μmol·mol-1 CO2 and at 400 – 500 μmol·m-2·s-1 PFD at 800 μmol·mol-1 CO2. For Kalanchoe similar results were obtained. Increasing the CO2 concentration from 370 to 800 μmol·mol-1 increased the CER in roses (48%) as well in Kalanchoe (69%). It was concluded that 15 to 20 mol·m-2·day-1 combined with about 24°C air temperature and high CO2 concentration will give a very good growth with lot of flowers within a short production time in miniature roses. For Kalanchoe 10 to 15 mol·m-2·day-1 combined with about 20°C and high CO2 produced a similar result.
文摘In this paper, it is shown that the laser radiation intensity required for complete ionization of vapors produced on an irradiated metal surface can be reduced by more than an order of magnitude through using pulsed laser radiation in combination with microwave radiation.
文摘Objective: To study the protective effect of ascorbic acid and curcumin against the abnormal estrous cycle and morphological changes in cells induced by repeated ultraviolet B(UVB)radiation in female Wistar rats.Methods: Sixteen female sexually mature Wistar rats weighing 130-150 g and aged 12-16 weeks were randomly divided into four groups.The control group received normal food and water ad libitum.The UVB group was exposed to a dose of 280 nm of UVB radiation for 2 h daily.The UVB+curcumin group received a dose of 280 nm of UVB radiation for 2 h daily and also an oral dose of curcumin(25 mg/kg body weight)daily.The UVB+ascorbic acid group received a dose of 280 nm of UVB radiation for 2 h daily and also an oral dose of ascorbic acid(250 mg/kg body weight)daily.All the treatments last for 15 consecutive days.Body and ovary weight and gonadosomatic index were measured.The stages(proestrus,estrus,metaestrus and diestrus)of the estrous cycle were determined by the cell types observed in the vaginal smear.Results: UVB radiation caused irregular alterations on the estrous cycle and morphological changes of the female Wistar rat as compared with the control group.Ascorbic acid and curcumin protected UVB-induced estrous phases and their cells.But curcumin showed greater protection than ascorbic acid.Conclusions: Ascorbic acid and curcumin at low doses can alleviate abnormal estrous cycle and morphological changes in cells induced by UVB radiations in female Wistar rats.
文摘An explanation is given for the thermal equilibrium in the biosphere, which is based in the equality between the thermal energy received from the sun and the thermal energy reemitted from the atmosphere to the space. In order to understand the origin of the energy that gives rise to the processes and phenomena taking place in the biosphere, it is necessary to take into account the free energy represented by the product of temperature times the change in entropy, T△S, whose magnitude can be attributed to the variation experimented by the wavelengths (or, consequently, the frequencies) of the radiations composing the radiation spectrum received from the sun compared with the radiation spectrum reemitted from the biosphere into the space. A simple discussion allows to predict that the entropy increase driving the processes is connected with a spontaneous conversion of high frequency radiations (with lower “content” of entropy) in radiations of lower frequencies (with higher “content” of entropy). A consequence of this is that high frequency radiations would correspond to more ordered states and, therefore, to less probable states than those corresponding to radiations of lower frequencies.
文摘The transverse magnetic (TM) radiation characteristics are investigated for a cylinder with N infinite axial slots of arbitrary opening size and location. The cylinder is a thin circular conductor and coated by an eccentric material. Fields are found by applying the boundary conditions to the cylindrical wave functions. The addition theorem of Bessel functions is used to obtain an infinite series solution in Fourier–Bessel series form. Results are computed by shrinking the generated infinite series to a finite number of terms and compared to other available data. Numerical results in graphical forms for different values are also developed and discussed for small eccentricities.
文摘In this study, we simulated space flight of the nematode, Caenorhabditis elegans, on the ground and examined how it is affected by space radiation and G-forces. We simulated G-forces during launch in a gravity acceleration laboratory device in order to identify and isolate the effects of the G-forces. Following this, we irradiated C. elegans with accelerated protons (MC-50 Cyclotron) and gamma rays (iR 222 machine) at the same physical dose. We calculated the expected radiation dose according to Reitz [1] and simulation programs (NASA AP8MIN [2], NASA AE8MAX [2], and CREAM86 [3]) for 1 month (dose rate: 6 × 10-3 Gy;2.8 × 10-2 Gy), 6 months (dose rate: 36 × 10-3 Gy;16.8 × 10-2 Gy), and 2 years (dose rate: 144 × 10-3 Gy;67.2 × 10-2 Gy) of space flight. There have been several trials that aimed to take C. elegans into orbit on US space shuttle missions including a mission on the shuttle Columbia. In this study, we simulated longer duration space flights and performed a whole-genome microarray analysis to observe phenotype variations whereas most such experiments were carried out during short duration space flights and focused on mutations and genotypic variations. We expect that the results of this study will be useful to predict the effects of long-term exposure of space radiation on living organisms.
文摘The results of experimental research of some effects in metal-insulator-semiconductor (MIS) structures induced by different types of radiation (50 MeV electrons, 12 keV gamma-quanta, 10 and 40 keV arsenic ions) are presented. It is found that there is a significant difference between the characters of radiation surface states (SS) formed by ionization and impact actions of the MIS structure irradiation at the insulator-semiconductor (I-S) interface. It is shown that the SS generation rate is increased in electric fields and depends on the MIS structure field electrode material.
基金supported by the National Natural Science Foundation of China (Grant Nos.11433004 and 11173020)the Top Talents Program of Yunnan Province,the Natural Science Foundation of Yunnan Province (2012FD055 and 2013FB063)the Young Teachers Program of Yuxi Normal University,and the Program for Innovative Research Team (in Science and Technology) in University of Yunnan Province (IRTSTYN)
文摘We investigate the spatial dependence of high energy electrons and their radiations in pulsar wind nebulae (PWNe). By assuming a time-dependent broken power-law injection and spatial dependence of convection velocity, magnetic field strength and diffusion coefficient on the radial distance of an expand- ing system, we numerically solve the Fokker-Planck transport equation including convection, diffusion, adiabatic loss and radiative loss in spherical coordinates, and investigate the effects of magnetic field, PWN age, maximum energy of electrons, and diffusion coefficient on electron spectra and non-thermal photon emissions. Our results indicate that (1) electron spectra and the corresponding photon spectra are a function of radial distance r of the expanding system; (2) for a given expansion velocity, the increase of the PWN age causes a slower decrease of the convection velocity (V ∝ r-β) and a more rapid decrease of the magnetic field strength (B ∝ r-1+β), but a more rapid increase of the diffusion coefficient (k∝ r1-β) because the index β decreases with the PWN age; and (3) the lower energy part of the electron spectra is dominated by convection and adiabatic loss, but the higher energy part is dominated by the competition between syn- chrotron loss and diffusion, and such a competition is a function of radial distance. Therefore the diffusion effect has an important role in the evolution of electron spectra as well as non-thermal photon spectra in a PWN.
文摘Spores are the biological structures formed out of sporulation from vegetative cells in adverse conditions.Being tolerant to many extreme environment and conditions,they escape and survives critical processing steps in the food industry that poses food and health safety problems,as is evident from the increase in reports of food-bome outbreaks due to spore-fomers.Electromagnetic radiation(EM)is used for rapid decontamination and sterilization purposes in the food industry.Many studies have reported a greater reduction in spore population upon irradiation with EM rays due to its impact on genomic material and other components of spores that destabilises overall structue and brings clonogenic death However,there is scattered literature regarding the mechanism of its inactivation and resistance against such damage.This review attempts to concisely evaluate the potential of electromagnetic radiations in spore inactivation and details its mechanism through a collective study of scientific results and repouts.It also briefs about the process of sporulation,the structure of spores and the role of its components in the resistance of spores to damage.Many studies,which demonstrated that combining various EM treatments might be an effective way for inactivation of spores,were discussed in detail.
文摘The ESA and CAS SMILE mission orbit is highly elliptical and will pass through multiple radiation environments.The Soft X-ray Imager(SXI)instrument aboard has a radiation shutter door designed to close when the surrounding radiation flux is high.The shutter door will close when passing below an altitude threshold to protect against trapped particles in the Earth’s Van Allen Belts.Therefore,two radiation environments can be approximated based on the shutter door position:open and closed.The instrument background for the CCDs(Charge-Coupled Devices)that form the focal plane array of the SXI were evaluated for the two environments.Due to the correlation of the space environment with the solar cycle,the solar minima and maxima,the background was also evaluated at these two extremes.The results demonstrated that the highest instrument background will occur during solar minima due to the main contributing source being Galactic Cosmic Rays(GCRs).It was also found that the open background was highest for solar minima and that the closed background was highest during solar maxima.This is due to the radiation shutter door acting as a scattering centre and the changes in the energy flux distribution of the GCRs between the two solar extremes.
基金supported by the National Natural Science Foundation of China(62305261,62305262)the Natural Science Foundation of Shaanxi Province(2024JC-YBMS-021,2024JC-YBMS-788,2023-JC-YB-065,2023-JC-QN-0693,2022JQ-652)+1 种基金the Xi’an Science and Technology Bureau of University Service Enterprise Project(23GXFW0043)the Cross disciplinary Research and Cultivation Project of Xi’an University of Architecture and Technology(2023JCPY-17)。
文摘As interest in double perovskites is growing,especially in applications like photovoltaic devices,understanding their mechanical properties is vital for device durability.Despite extensive exploration of structure and optical properties,research on mechanical aspects is limited.This article builds a vacancyordered double perovskite model,employing first-principles calculations to analyze mechanical,bonding,electronic,and optical properties.Results show Cs_(2)Hfl_(6),Cs_(2)SnBr_(6),Cs_(2)SnI_(6),and Cs_(2)PtBr_(6)have Young's moduli below 13 GPa,indicating flexibility.Geometric parameters explain flexibility variations with the changes of B and X site composition.Bonding characteristic exploration reveals the influence of B and X site electronegativity on mechanical strength.Cs_(2)SnBr_(6)and Cs_(2)PtBr_(6)are suitable for solar cells,while Cs_(2)HfI_(6)and Cs_(2)TiCl_(6)show potential for semi-transparent solar cells.Optical property calculations highlight the high light absorption coefficients of up to 3.5×10^(5) cm^(-1)for Cs_(2)HfI_(6)and Cs_(2)TiCl_(6).Solar cell simulation shows Cs_(2)PtBr_(6)achieves 22.4%of conversion effciency.Cs_(2)ZrCl_(6)holds promise for ionizing radiation detection with its 3.68 eV bandgap and high absorption coefficient.Vacancy-ordered double perovskites offer superior flexibility,providing valuable insights for designing stable and flexible devices.This understanding enhances the development of functional devices based on these perovskites,especially for applications requiring high stability and flexibility.