Pub Date : 2020-09-23DOI: 10.11648/J.AJPA.20200805.11
V. Varlamov, A. Davydov, V. Orlin
The experimental data for photoneutron reaction cross sections for 127I obtained using beams of quasimonoenergetic annihilation photons and the method of neutron multiplicity-sorting at Livermore (USA) and Saclay (France) were analyzed using objective physical data reliability criteria. It was found that data of both laboratories contain significant systematic uncertainties and therefore are not reliable. New data for partial and total photoneutron reactions cross sections for 127I satisfied physical criteria of data reliability were evaluated using experimental-theoretical method based on both experimental neutron yield reaction cross-section and results of calculation in the combined photonucleon reaction model (CPNRM). The neutron yield reaction cross-section obtained at Saclay (France) was used in evaluation procedure. The newly evaluated cross sections for partial (γ, 1n), (γ, 2n) and (γ, 3n) reactions for 127I were used for discussion in detail the problems of significant disagreements between experimental data for many nuclei obtained at Saclay and Livermore. It was found that systematic uncertainties of experimental data for the (γ, 1n), (γ, 2n), and (γ, 3n) reactions cross sections for 127I obtained at both laboratories are of different nature. One of the reasons of noticeable systematic uncertainties of cross sections obtained are the shortcomings of the procedures used to separate counts into 1n, 2n, and 3n events. At the same time it was shown that the main reason of significant disagreements between new evaluated data and data obtained at Livermore experiment for 127I is the loss of many neutrons from the (γ, 1n) reaction. This situation is analogous to those in Livermore experiments for 75As and 181Ta.
{"title":"Photodisintegration of 127I: Systematic Uncertainties of Experiments and Data Evaluated Using Physical Criteria","authors":"V. Varlamov, A. Davydov, V. Orlin","doi":"10.11648/J.AJPA.20200805.11","DOIUrl":"https://doi.org/10.11648/J.AJPA.20200805.11","url":null,"abstract":"The experimental data for photoneutron reaction cross sections for 127I obtained using beams of quasimonoenergetic annihilation photons and the method of neutron multiplicity-sorting at Livermore (USA) and Saclay (France) were analyzed using objective physical data reliability criteria. It was found that data of both laboratories contain significant systematic uncertainties and therefore are not reliable. New data for partial and total photoneutron reactions cross sections for 127I satisfied physical criteria of data reliability were evaluated using experimental-theoretical method based on both experimental neutron yield reaction cross-section and results of calculation in the combined photonucleon reaction model (CPNRM). The neutron yield reaction cross-section obtained at Saclay (France) was used in evaluation procedure. The newly evaluated cross sections for partial (γ, 1n), (γ, 2n) and (γ, 3n) reactions for 127I were used for discussion in detail the problems of significant disagreements between experimental data for many nuclei obtained at Saclay and Livermore. It was found that systematic uncertainties of experimental data for the (γ, 1n), (γ, 2n), and (γ, 3n) reactions cross sections for 127I obtained at both laboratories are of different nature. One of the reasons of noticeable systematic uncertainties of cross sections obtained are the shortcomings of the procedures used to separate counts into 1n, 2n, and 3n events. At the same time it was shown that the main reason of significant disagreements between new evaluated data and data obtained at Livermore experiment for 127I is the loss of many neutrons from the (γ, 1n) reaction. This situation is analogous to those in Livermore experiments for 75As and 181Ta.","PeriodicalId":329149,"journal":{"name":"American Journal of Physics and Applications","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128859165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-17DOI: 10.11648/J.AJPA.20200804.12
Voxob Rustamovich Rasulov, R. Rasulov, Iqboljon Mamirjonovich Eshboltayev, R. R. Sultanov
The transparency coefficients of the semiconductor structure consisting of alternating asymmetric potential barriers and wells are calculated, where taken into account the Bastard condition. It is shown that both in the above-barrier and over barrier passage of electrons, tunneling oscillations arise. The amplitude, in this case, is determined not only by the values of the wave vectors, but from the values of the effective masses of the current carriers. This oscillation does not disappear even in symmetric structures if they have a difference in the effective masses of current carriers located in two neighboring regions. In symmetrical structures, an oscillation of the coefficient of the above-barrier passage of a particle depending on its energy should be observed without taking into account the Bastard condition. Calculations show that for equal values of the width of the well and the potential barrier, as well as jumps in the potential of the barrier or well, the amplitude of the oscillations of the coefficient of over-barrier passage of particles is greater than the coefficient of passage above the well. In the case of an asymmetric structure, these considerations remain valed, but the physical nature of the parameters, for example, the number of oscillations, reflection and transmission coefficients, strongly depends on the ratio of the effective masses of electrons in neighboring layers and from the ratio of the height of the left and right potential barrier (regarding to the well). In an asymmetric (and in a symmetric, but with different effective masses of electrons in different layers) semiconductor structure, oscillation should be observed depending on the coefficient of transmission through the potential barrier on the energy of electron. This oscillation is caused by the interference of waves going to the barrier and reflected from the potential barrier. Such an interference phenomenon in the structure does not disappear even in a symmetric structure due to the difference in the effective masses of electrons located in different regions of the structure. The electronic states of a multilayer semiconductor structure consisting of alternating potential wells and barriers are analyzed.
{"title":"Sub-barrier and Above-barrier Electron Transport Through Multilayer Semiconductors","authors":"Voxob Rustamovich Rasulov, R. Rasulov, Iqboljon Mamirjonovich Eshboltayev, R. R. Sultanov","doi":"10.11648/J.AJPA.20200804.12","DOIUrl":"https://doi.org/10.11648/J.AJPA.20200804.12","url":null,"abstract":"The transparency coefficients of the semiconductor structure consisting of alternating asymmetric potential barriers and wells are calculated, where taken into account the Bastard condition. It is shown that both in the above-barrier and over barrier passage of electrons, tunneling oscillations arise. The amplitude, in this case, is determined not only by the values of the wave vectors, but from the values of the effective masses of the current carriers. This oscillation does not disappear even in symmetric structures if they have a difference in the effective masses of current carriers located in two neighboring regions. In symmetrical structures, an oscillation of the coefficient of the above-barrier passage of a particle depending on its energy should be observed without taking into account the Bastard condition. Calculations show that for equal values of the width of the well and the potential barrier, as well as jumps in the potential of the barrier or well, the amplitude of the oscillations of the coefficient of over-barrier passage of particles is greater than the coefficient of passage above the well. In the case of an asymmetric structure, these considerations remain valed, but the physical nature of the parameters, for example, the number of oscillations, reflection and transmission coefficients, strongly depends on the ratio of the effective masses of electrons in neighboring layers and from the ratio of the height of the left and right potential barrier (regarding to the well). In an asymmetric (and in a symmetric, but with different effective masses of electrons in different layers) semiconductor structure, oscillation should be observed depending on the coefficient of transmission through the potential barrier on the energy of electron. This oscillation is caused by the interference of waves going to the barrier and reflected from the potential barrier. Such an interference phenomenon in the structure does not disappear even in a symmetric structure due to the difference in the effective masses of electrons located in different regions of the structure. The electronic states of a multilayer semiconductor structure consisting of alternating potential wells and barriers are analyzed.","PeriodicalId":329149,"journal":{"name":"American Journal of Physics and Applications","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122675389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-17DOI: 10.11648/J.AJPA.20200804.11
M. Petrov
Based on experimental examples, the strength characteristics of metal alloys and composites under tensile and compressive loads are considered to demonstrate both their similarity and difference. Under tensile loads, their behavior is essentially the same. Under compressive loads, the composite shows different properties, but similar to the behavior of a metal alloy under tension. When tensioned and compressed, it fractured as a material with a different structure. When a metal alloy is cyclically compressed, the damage accumulation process is attenuated, which reduces the alloy longevity during subsequent tension. The analysis of experimental data for various types of loading from the standpoint of the kinetic concept of fracture is carried out. Instead of a number of incompatible approaches or a formal description of experimental data, that based on the theory of reaction rates is used. Mathematical modeling of processes is carried out using rheological models of the material. Structural models of the material, called physical media, reflect the thermodynamic processes of flow, failure, and changes in the structure of the material. Parametric identification of structural models is carried out on the basis of the minimum necessary basic experiment: loading of specimens with different speeds at several temperature values and by the amplitude dependence of inelasticity. Based on results of these experiments, the scope of applicability conditions for this material and test modes necessary for parametric identification of models are selected. One fracture criterion is used, which formally corresponds to the achievement of a threshold concentration of micro-damage in any volume of the material, leading to macro-fracture. The application of mathematical models for calculating the longevity of materials depending on the temperature and force loading conditions and the nature of their changes is shown. Calculations of longevity under constant, monotonously increasing and variable loads under conditions of constant or changing temperatures are based on the relationship of plastic flow and failure processes distributed over the volume of the material. They are performed numerically by time steps depending on the ratio of the rate of change of temperature and stresses.
{"title":"Mathematical Modeling of Failure and Deformation Processes in Metal Alloys and Composites","authors":"M. Petrov","doi":"10.11648/J.AJPA.20200804.11","DOIUrl":"https://doi.org/10.11648/J.AJPA.20200804.11","url":null,"abstract":"Based on experimental examples, the strength characteristics of metal alloys and composites under tensile and compressive loads are considered to demonstrate both their similarity and difference. Under tensile loads, their behavior is essentially the same. Under compressive loads, the composite shows different properties, but similar to the behavior of a metal alloy under tension. When tensioned and compressed, it fractured as a material with a different structure. When a metal alloy is cyclically compressed, the damage accumulation process is attenuated, which reduces the alloy longevity during subsequent tension. The analysis of experimental data for various types of loading from the standpoint of the kinetic concept of fracture is carried out. Instead of a number of incompatible approaches or a formal description of experimental data, that based on the theory of reaction rates is used. Mathematical modeling of processes is carried out using rheological models of the material. Structural models of the material, called physical media, reflect the thermodynamic processes of flow, failure, and changes in the structure of the material. Parametric identification of structural models is carried out on the basis of the minimum necessary basic experiment: loading of specimens with different speeds at several temperature values and by the amplitude dependence of inelasticity. Based on results of these experiments, the scope of applicability conditions for this material and test modes necessary for parametric identification of models are selected. One fracture criterion is used, which formally corresponds to the achievement of a threshold concentration of micro-damage in any volume of the material, leading to macro-fracture. The application of mathematical models for calculating the longevity of materials depending on the temperature and force loading conditions and the nature of their changes is shown. Calculations of longevity under constant, monotonously increasing and variable loads under conditions of constant or changing temperatures are based on the relationship of plastic flow and failure processes distributed over the volume of the material. They are performed numerically by time steps depending on the ratio of the rate of change of temperature and stresses.","PeriodicalId":329149,"journal":{"name":"American Journal of Physics and Applications","volume":"124 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130301544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-16DOI: 10.11648/j.ajpa.20200803.12
Y. Shin
This study reports tunneling through a one-dimensional (1D) square potential barrier (SPB) under fluctuations in an observer’s frame of reference (OFR). To date, tunneling through an SPB has been studied under the assumption that the OFR remains constant throughout the tunneling measurements; therefore, the change of the tunneling probability when the OFR is assumed to fluctuate remains unanswered. In this paper, a 1D SPB is considered under fluctuations of an OFR. The average transmission probability of a particle through an SBP for two types of OFR fluctuations (periodic-square-wave and periodic-sawtooth-wave fluctuations) is formulated in time representations. Under these types of fluctuations, the average transmission probability gradually increases with a particle’s energy, which is saturated to the transmission probability in the case of the stationary OFR at a much greater energy than the amplitude of the fluctuations. The average transmission probability is much higher at the amplitude of the fluctuations in the case of periodic-square-wave fluctuations. Therefore, the average transmission probability with a particle’s energy has the potential to reveal the distribution of OFR fluctuations.
{"title":"Tunneling Through a One-Dimensional Square Potential Barrier Under Fluctuations in an Observer’s Frame of Reference","authors":"Y. Shin","doi":"10.11648/j.ajpa.20200803.12","DOIUrl":"https://doi.org/10.11648/j.ajpa.20200803.12","url":null,"abstract":"This study reports tunneling through a one-dimensional (1D) square potential barrier (SPB) under fluctuations in an observer’s frame of reference (OFR). To date, tunneling through an SPB has been studied under the assumption that the OFR remains constant throughout the tunneling measurements; therefore, the change of the tunneling probability when the OFR is assumed to fluctuate remains unanswered. In this paper, a 1D SPB is considered under fluctuations of an OFR. The average transmission probability of a particle through an SBP for two types of OFR fluctuations (periodic-square-wave and periodic-sawtooth-wave fluctuations) is formulated in time representations. Under these types of fluctuations, the average transmission probability gradually increases with a particle’s energy, which is saturated to the transmission probability in the case of the stationary OFR at a much greater energy than the amplitude of the fluctuations. The average transmission probability is much higher at the amplitude of the fluctuations in the case of periodic-square-wave fluctuations. Therefore, the average transmission probability with a particle’s energy has the potential to reveal the distribution of OFR fluctuations.","PeriodicalId":329149,"journal":{"name":"American Journal of Physics and Applications","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116773497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-10DOI: 10.11648/j.ajpa.20200803.11
G. Ustinova, V. Alexeev
To study radiation environment in the interplanetary space, cosmogenic radionuclides in meteorites, the production rates of which are in direct proportionality to the intensity of cosmic rays, are used. The contents of cosmogenic radionuclides of different half-lives T1/2, measured in 42 stony meteorites (chondrites) having sequentially fallen onto the Earth during the period of 1959–2016, are analyzed. They are accumulated by the galactic cosmic rays (GCRs) along the orbits of the chondrites before their falls onto the Earth at some average heliocentric distances, depending on the size of the chondrite orbit and on T1/2 of the radionuclide. The comparison with the calculated production rates of radionuclides in the identical chondrites for isotropic irradiation by the GCRs at ~ 1 AU is demonstrated. The calculations are based on the stratospheric balloon monthly data on the GCR intensity [1] for the periods of accumulation of each radionuclide in each chondrite. The dependence of production rates of the radionuclides of different half-lives upon the GCR variations in the heliosphere is studied. The obtained long set of homogeneous data on cosmogenic radionuclide production rates in consecutively fallen chondrites provides the unique information on the space-time continuum of the cosmogenic radionuclide production rates and their variations over a long-time scale, which could be useful in the correlative analyses of processes in the inner heliosphere and, thus, in the forecast of radiation situation, which is important for the predicted manned flights.
{"title":"Temporal and Spatial Variations of Cosmogenic Radionuclide Production Rates in Chondrites During Their Passage Through the Inner Heliosphere","authors":"G. Ustinova, V. Alexeev","doi":"10.11648/j.ajpa.20200803.11","DOIUrl":"https://doi.org/10.11648/j.ajpa.20200803.11","url":null,"abstract":"To study radiation environment in the interplanetary space, cosmogenic radionuclides in meteorites, the production rates of which are in direct proportionality to the intensity of cosmic rays, are used. The contents of cosmogenic radionuclides of different half-lives T1/2, measured in 42 stony meteorites (chondrites) having sequentially fallen onto the Earth during the period of 1959–2016, are analyzed. They are accumulated by the galactic cosmic rays (GCRs) along the orbits of the chondrites before their falls onto the Earth at some average heliocentric distances, depending on the size of the chondrite orbit and on T1/2 of the radionuclide. The comparison with the calculated production rates of radionuclides in the identical chondrites for isotropic irradiation by the GCRs at ~ 1 AU is demonstrated. The calculations are based on the stratospheric balloon monthly data on the GCR intensity [1] for the periods of accumulation of each radionuclide in each chondrite. The dependence of production rates of the radionuclides of different half-lives upon the GCR variations in the heliosphere is studied. The obtained long set of homogeneous data on cosmogenic radionuclide production rates in consecutively fallen chondrites provides the unique information on the space-time continuum of the cosmogenic radionuclide production rates and their variations over a long-time scale, which could be useful in the correlative analyses of processes in the inner heliosphere and, thus, in the forecast of radiation situation, which is important for the predicted manned flights.","PeriodicalId":329149,"journal":{"name":"American Journal of Physics and Applications","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123504349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-05DOI: 10.11648/J.AJPA.20200802.12
J. Wolny, R. Strzałka
In this paper a direct derivation of the dynamics of objects moving with relativistic speeds is presented, based on two assumptions: (i) energy and mass of an object in motion are equivalent (mass-energy equivalence, known in special relativity and confirmed in experiments), (ii) an object can be considered as a variable-mass object with mass increasing with velocity (in some interpretations referred to as relativistic mass). In the presented approach the postulate on the constancy of the speed of light is not necessary. Also, the four-dimensional Minkowski spacetime is not used and no assumptions on symmetries are made. Therefore, it applies for sub- and superluminal speeds with the speed of light in a vacuum c being the critical speed, which separates the two interesting regions of speeds. The solution for v c opens an unknown and unintuitive behavior, which should be subjected to experimental investigation. In the range of superluminal speeds, a solution in which the energy of the material particle decreases as its speed increases is obtained. The critical speed in media other than a vacuum should be replaced to a speed environment-dependent, other than c.
{"title":"Description of the Motion of Objects with Sub- and Superluminal Speeds","authors":"J. Wolny, R. Strzałka","doi":"10.11648/J.AJPA.20200802.12","DOIUrl":"https://doi.org/10.11648/J.AJPA.20200802.12","url":null,"abstract":"In this paper a direct derivation of the dynamics of objects moving with relativistic speeds is presented, based on two assumptions: (i) energy and mass of an object in motion are equivalent (mass-energy equivalence, known in special relativity and confirmed in experiments), (ii) an object can be considered as a variable-mass object with mass increasing with velocity (in some interpretations referred to as relativistic mass). In the presented approach the postulate on the constancy of the speed of light is not necessary. Also, the four-dimensional Minkowski spacetime is not used and no assumptions on symmetries are made. Therefore, it applies for sub- and superluminal speeds with the speed of light in a vacuum c being the critical speed, which separates the two interesting regions of speeds. The solution for v c opens an unknown and unintuitive behavior, which should be subjected to experimental investigation. In the range of superluminal speeds, a solution in which the energy of the material particle decreases as its speed increases is obtained. The critical speed in media other than a vacuum should be replaced to a speed environment-dependent, other than c.","PeriodicalId":329149,"journal":{"name":"American Journal of Physics and Applications","volume":"326 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123482808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-11DOI: 10.11648/j.ajpa.20200802.11
Longyang Jia, W. Shou, Bing Hu
The primary problem of safety and efficiency for the high intensity therapeutic ultrasound (HITU) is the acoustic measure and dose control. The key technique is the pressure and intensity in the acoustic field especial in the focal region using the small calibrated hydrophone. The calibration accuracy of the used hydrophone is very important for HITU. Although the small hydrophone calibration has realized but there was no report of the hydrophone calibration in high pressure field. In this paper, our objective is to develop an absolute calibration method for the measurement of free field voltage sensitivity of hydrophone for high intensity focused ultrasound. First the acoustic pressure at the focal point by the self-reciprocity method of spherically curved auxiliary transducer is calibrated, then the free field voltage sensitivity of hydrophone at the geometric focal point of the calibrated pressure is obtained. The spatial average effect of acoustic pressure on hydrophone surface at the focal point is theoretically modified, and the expression and value table of correction coefficient of spatial average effect of hydrophone are given. The maximum acoustic pressure measured at the focal point was up to 5.58MPa (1.02kW/cm2) and used to calibrate a hydrophone from 0.95 MHz to 1.10 MHz with maximum local distortion parameter 0.72. The results show the rationality and feasibility of the measurement principle and method.
{"title":"Reciprocity Calibration of Hydrophones in High Intensity Focused Ultrasound Field","authors":"Longyang Jia, W. Shou, Bing Hu","doi":"10.11648/j.ajpa.20200802.11","DOIUrl":"https://doi.org/10.11648/j.ajpa.20200802.11","url":null,"abstract":"The primary problem of safety and efficiency for the high intensity therapeutic ultrasound (HITU) is the acoustic measure and dose control. The key technique is the pressure and intensity in the acoustic field especial in the focal region using the small calibrated hydrophone. The calibration accuracy of the used hydrophone is very important for HITU. Although the small hydrophone calibration has realized but there was no report of the hydrophone calibration in high pressure field. In this paper, our objective is to develop an absolute calibration method for the measurement of free field voltage sensitivity of hydrophone for high intensity focused ultrasound. First the acoustic pressure at the focal point by the self-reciprocity method of spherically curved auxiliary transducer is calibrated, then the free field voltage sensitivity of hydrophone at the geometric focal point of the calibrated pressure is obtained. The spatial average effect of acoustic pressure on hydrophone surface at the focal point is theoretically modified, and the expression and value table of correction coefficient of spatial average effect of hydrophone are given. The maximum acoustic pressure measured at the focal point was up to 5.58MPa (1.02kW/cm2) and used to calibrate a hydrophone from 0.95 MHz to 1.10 MHz with maximum local distortion parameter 0.72. The results show the rationality and feasibility of the measurement principle and method.","PeriodicalId":329149,"journal":{"name":"American Journal of Physics and Applications","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123071864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-23DOI: 10.11648/J.AJPA.20210904.12
Zhong Xu, Jun Huang, Zaifeng Xu, Xiao-ping Liu, Hongyan Wu
Plasma Surface Metallurgy/Alloying is a kind of surface metallurgy/alloying to employ low temperature plasma produced by glow discharge to diffuse alloying elements into the surface of substrate material to form an alloy layer. The first plasma surface metallurgy technology is plasma nitriding invented by German scientist Dr. Bernard Berghuas in 1930. He was the first person to apply glow discharge to realize the surface alloying. In order to break the limitation of plasma nitriding technology, which can only be applied to a few non-metallic gaseous elements such as nitrogen, carbon, sulfur, the "Double Glow Discharge Phenomenon"was found in 1978. Based on this phenomenon the "Double Glow Plasma Surface Metallurgy Technology", also known as the "Xu-Tec Process" was invented in 1980. It can utilize any chemical elements in the periodic table including solid metallic, gas non-metallic elements and their combination to realize plasma surface alloying, hence greatly expanded the field of surface alloying. Countless surface alloys with high hardness, wear resistance and corrosion resistance, such as high speed steels, nickel base alloys and burn resistant alloys have been produced on the surfaces of a variety of materials. This technology may greatly improve the surface properties of metal materials, comprehensively improve the quality of mechanical products, save a lot of precious alloy elements for human beings. Based on the plasma nitriding technology, the Xu-Tec Process has opened up a new material engineering field of "Plasma Surface Metallurgy". This Review Article briefly presents the history of glow discharge and surface alloying, double glow discharge phenomenon, basic principle and current status of Double Glow Plasma Surface Metallurgy/Alloying. Industrial applications, advantages and future potential of the Xu-Tec process are also presented.
{"title":"Plasma Surface Metallurgy of Materials Based on Double Glow Discharge Phenomenon","authors":"Zhong Xu, Jun Huang, Zaifeng Xu, Xiao-ping Liu, Hongyan Wu","doi":"10.11648/J.AJPA.20210904.12","DOIUrl":"https://doi.org/10.11648/J.AJPA.20210904.12","url":null,"abstract":"Plasma Surface Metallurgy/Alloying is a kind of surface metallurgy/alloying to employ low temperature plasma produced by glow discharge to diffuse alloying elements into the surface of substrate material to form an alloy layer. The first plasma surface metallurgy technology is plasma nitriding invented by German scientist Dr. Bernard Berghuas in 1930. He was the first person to apply glow discharge to realize the surface alloying. In order to break the limitation of plasma nitriding technology, which can only be applied to a few non-metallic gaseous elements such as nitrogen, carbon, sulfur, the \"Double Glow Discharge Phenomenon\"was found in 1978. Based on this phenomenon the \"Double Glow Plasma Surface Metallurgy Technology\", also known as the \"Xu-Tec Process\" was invented in 1980. It can utilize any chemical elements in the periodic table including solid metallic, gas non-metallic elements and their combination to realize plasma surface alloying, hence greatly expanded the field of surface alloying. Countless surface alloys with high hardness, wear resistance and corrosion resistance, such as high speed steels, nickel base alloys and burn resistant alloys have been produced on the surfaces of a variety of materials. This technology may greatly improve the surface properties of metal materials, comprehensively improve the quality of mechanical products, save a lot of precious alloy elements for human beings. Based on the plasma nitriding technology, the Xu-Tec Process has opened up a new material engineering field of \"Plasma Surface Metallurgy\". This Review Article briefly presents the history of glow discharge and surface alloying, double glow discharge phenomenon, basic principle and current status of Double Glow Plasma Surface Metallurgy/Alloying. Industrial applications, advantages and future potential of the Xu-Tec process are also presented.","PeriodicalId":329149,"journal":{"name":"American Journal of Physics and Applications","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116151975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-18DOI: 10.11648/J.AJPA.20200801.12
J. A. Owolabi, M. Onimisi, Jessica Amuchi Ukwenya, Alexander Bulus Bature, Ugbe Raphael Ushiekpan
Tin perovskite (CH3NH3SnI3) have attracted a lot of attention and could be a viable alternative material to replace lead perovskite in thin film solar cells. A detailed understanding on the effects of each component of a solar cell on its output performance is needed to further develop the technology. In this work, a numerical simulation of a planar hetero-junction tin based perovskite solar cell using Solar Cell Capacitance Simulator (SCAPS) to study some parameters that can influence the performance of tin PSC with Cu2O as HTL and ZnSe as ETL performed. The thickness of absorber material, ETL and HTL, the bandgap of absorber material and ETL was investigated. Results revealed that the thickness and bandgap of the absorber material and ETL of ZnSe strongly influence the PCE of the device. The performance of the cell increases with reduction in thickness of ZnSe. ZnSe is found to be a replacement for TiO2 which is expensive. Cuprous oxide of HTL in tin based PSC is efficient and better than the expensive spiro-MeOTAD which is easily degradable. Furthermore, results of simulation and optimization of various thicknesses indicates that ZnSe has a PCE of 21.11%, FF of 68.33%, JSC of 33.51mA/cm2 and VOC of 0.92V. These values slightly increase after optimization of parameters to PCE of 22.28%, FF of 70.94%, JSC of 31.01mA/cm2 and VOC of 1.01V.
{"title":"Investigating the Effect of ZnSe (ETM) and Cu2O (HTM) on Absorber Layer on the Performance of Pervoskite Solar Cell Using SCAPS-1D","authors":"J. A. Owolabi, M. Onimisi, Jessica Amuchi Ukwenya, Alexander Bulus Bature, Ugbe Raphael Ushiekpan","doi":"10.11648/J.AJPA.20200801.12","DOIUrl":"https://doi.org/10.11648/J.AJPA.20200801.12","url":null,"abstract":"Tin perovskite (CH3NH3SnI3) have attracted a lot of attention and could be a viable alternative material to replace lead perovskite in thin film solar cells. A detailed understanding on the effects of each component of a solar cell on its output performance is needed to further develop the technology. In this work, a numerical simulation of a planar hetero-junction tin based perovskite solar cell using Solar Cell Capacitance Simulator (SCAPS) to study some parameters that can influence the performance of tin PSC with Cu2O as HTL and ZnSe as ETL performed. The thickness of absorber material, ETL and HTL, the bandgap of absorber material and ETL was investigated. Results revealed that the thickness and bandgap of the absorber material and ETL of ZnSe strongly influence the PCE of the device. The performance of the cell increases with reduction in thickness of ZnSe. ZnSe is found to be a replacement for TiO2 which is expensive. Cuprous oxide of HTL in tin based PSC is efficient and better than the expensive spiro-MeOTAD which is easily degradable. Furthermore, results of simulation and optimization of various thicknesses indicates that ZnSe has a PCE of 21.11%, FF of 68.33%, JSC of 33.51mA/cm2 and VOC of 0.92V. These values slightly increase after optimization of parameters to PCE of 22.28%, FF of 70.94%, JSC of 31.01mA/cm2 and VOC of 1.01V.","PeriodicalId":329149,"journal":{"name":"American Journal of Physics and Applications","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123755590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-02-20DOI: 10.11648/J.AJPA.20200801.11
Shao-rui Huang
The precession mechanism and stability of gyroscope is an outstanding problem. It has been widely believed for a long time that the precession of gyroscope is the result of the action of heavy moment. But this is not completely consistent with the experimental facts. This paper introduces the experimental phenomena of gyroscopic precession on the horizontal plane, presents the laws of rotational inertia and micro deformation action, gives the empirical expression of micro deformation action. The experimental phenomena of gyro precession are analyzed based on the principle of virtual fixed axis rotation balance and the law of conservation of momentum moment. The condition of whether the gyro can recover stable rotation state in certain condition is given, the determinants of precession angular velocity and rotation angular velocity of gyroscope and their relations are also given. The stability and precession mechanism of the gyroscope on the horizontal plane are explained comprehensively.
{"title":"Interpretation of Gyro Stability and Precession Mechanism by Law of Rotational Inertia","authors":"Shao-rui Huang","doi":"10.11648/J.AJPA.20200801.11","DOIUrl":"https://doi.org/10.11648/J.AJPA.20200801.11","url":null,"abstract":"The precession mechanism and stability of gyroscope is an outstanding problem. It has been widely believed for a long time that the precession of gyroscope is the result of the action of heavy moment. But this is not completely consistent with the experimental facts. This paper introduces the experimental phenomena of gyroscopic precession on the horizontal plane, presents the laws of rotational inertia and micro deformation action, gives the empirical expression of micro deformation action. The experimental phenomena of gyro precession are analyzed based on the principle of virtual fixed axis rotation balance and the law of conservation of momentum moment. The condition of whether the gyro can recover stable rotation state in certain condition is given, the determinants of precession angular velocity and rotation angular velocity of gyroscope and their relations are also given. The stability and precession mechanism of the gyroscope on the horizontal plane are explained comprehensively.","PeriodicalId":329149,"journal":{"name":"American Journal of Physics and Applications","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116903210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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