American Hollywood animated films have conquered the world.In recent years,many successful works have appeared in domestic animated films,bringing new vitality to the Chinese animated film industry.Based on Lacan’s M...American Hollywood animated films have conquered the world.In recent years,many successful works have appeared in domestic animated films,bringing new vitality to the Chinese animated film industry.Based on Lacan’s Mirror Stage Theory,this study attempts to start from the bravery of Judy and Nezha,the protagonists of Zootopia(2016)and Nezha(2019).It analyzes and compares their embodiment,formation,influence and reflection with real society to solve the problems of the two brave characters’formation causes,characteristic differences and social influences,including racial discrimination,individualism in American society and family problems in Chinese society.This study sheds light on the transmission of intercultural values in animated films.展开更多
According to the classical mechanics the energy of a celestial body circulating in the solar system is a constant term. This energy is defined by the masses product of the larger and smaller body entering into a mutua...According to the classical mechanics the energy of a celestial body circulating in the solar system is a constant term. This energy is defined by the masses product of the larger and smaller body entering into a mutual attraction as well as the size of the major semiaxis characteristic for the corresponding Kepler orbit. A special situation concerns the planet interaction with the Sun because of a systematic decrease of the Sun mass due to the luminosity effect. The aim of the paper is to point out that even in the case of perfectly constant interacting masses the energy of the moving body should decrease when a quantum treatment of the body motion is considered. The rate of the energy decrease is extremely small, nevertheless it gives a shortening of the distance between the interacting bodies leading to a final effect of a touch of the larger body and a smaller one.展开更多
The performances of turbine blades have a significant impact on the energy conversion efficiency of vertical solar power plants.In the present study,such a relationship is assessed by considering two kinds of airfoil ...The performances of turbine blades have a significant impact on the energy conversion efficiency of vertical solar power plants.In the present study,such a relationship is assessed by considering two kinds of airfoil blades,designed by using the Wilson theory.In particular,numerical simulations are conducted using the SST K−ω model and assuming a wind speed of 3–6 m/s and seven or eight blades.The two airfoils are the NACA63121(with a larger chord length)and the AMES63212;It is shown that the torsion angle of the former is smaller,and its wind drag ratio is larger;furthermore,the resistance is increased by about 66.3%on average.Within the scope of the study,the results show that the NACA63212 airfoil is better than the AMES63212 airfoil in terms of power,with an average improvement of about 2.8%.The simulation results have a certain guiding significance for selecting turbine blade airfoils and improving turbine efficiency.展开更多
Time and environmental physical activity are involved in timing of many medical events. In a recent study published by the National Academy of Science, USA it was shown that month of birth is related to longevity. The...Time and environmental physical activity are involved in timing of many medical events. In a recent study published by the National Academy of Science, USA it was shown that month of birth is related to longevity. The aim of this study was to check the month of birth distribution in a great group of AMI patients of both gender, one of the great killers in the developed countries, to check the mentioned paradigm of month of birth and longevity. Methods & Patients: Patients admitted to Cardiology Departments of a tertiary University Hospital in Kaunas, Lithuania with AMI at years 1990-2010 (n-22047) were studied. Month of birth of these patients, total and both gender were checked. Monthly, quarterly and trimester comparison were done. Statistical differences established using t-Student test and distribution by percents of the yearly months of birth. Results: It was a significant difference in the month of birth of the studied AMI population. January and first quarter and trimester born patients were more often in the studied AMI patients group. The higher morbidity by Cardiovascular diseases can be a significant ingredient in the structure of population longevity. Possible mechanisms explaining our findings are discussed. Conclusion: In the AMI population people born in January, first quarter or trimester of the year are dominating in both gender groups. The results of this study can be an additional confirmation of the paradigm about links between month of birth and longevity.展开更多
Based on the similarity theory,a scale effect model of the spraying water cooling system of Shanghai expo Theme Pavilion's roof was set up.According to the typical weather conditions in Shanghai city,different mod...Based on the similarity theory,a scale effect model of the spraying water cooling system of Shanghai expo Theme Pavilion's roof was set up.According to the typical weather conditions in Shanghai city,different models were analyzed on solar radiation,and different heat transfer amount was obtained.And the following conclusions could be made:At the sunny day of summer in Shanghai,the temperature of inner roof with sprinkling system descended about 3 ℃,and the air conditioning load of the whole Theme Pavilion descend more than 320 kW.展开更多
For some specific catalytic reaction, how to construct active sites on two dimensional materials is of great scientific significance. Dye-sensitized solar cells(DSCs) can be viewed as one representative photovoltaic...For some specific catalytic reaction, how to construct active sites on two dimensional materials is of great scientific significance. Dye-sensitized solar cells(DSCs) can be viewed as one representative photovoltaics because in which liquid electrolyte with triiodide/iodide(I;/I;) as redox couples are involved. In this study, amino-functionalized graphene(AFG) has been designed according to theoretically analyzing iodine reduction reaction(IRR) processes and rationally screening the volcanic plot. Then, such AFG has been successfully synthesized by a simple hydrothermal method and shows high electrocatalytic activity towards IRR when serving as counter electrode in DSCs. Finally, a high conversion efficiency of 7.39% by AFG-based DSCs was obtained, which is close to that using Pt as counter electrode.展开更多
A recent development in climate research is the recognition that space activity such as solar flares, gamma ray bursts, supernovas etc. can have a significant impact on the Earth. The existing methods of modelling spa...A recent development in climate research is the recognition that space activity such as solar flares, gamma ray bursts, supernovas etc. can have a significant impact on the Earth. The existing methods of modelling space activity do not model these phenomena explicitly. Instead, their effect on ionization rates is formulated and then built into existing climate models. In this paper, based on the authors’ earlier work, several analytical approaches for modelling a solar flare hitting the Earth are presented. These methods can also be used for modelling gamma-ray bursts or cosmic rays striking our planet. In addition, a method of calculating the total amount of radiation received during a solar flare is proposed. The future use of the proposed modelling approaches within comprehensive global climate models allows for explicit modelling of space activity and provides a new pathway for studying the possible effects of this activity on the Earth.展开更多
Since the seminal work by Kojima et al. in 2009, solar cells based on hybrid organic-inorganic perovskites have attracted considerable attention and experienced an exponential growth, with photovoltaic efficiencies as...Since the seminal work by Kojima et al. in 2009, solar cells based on hybrid organic-inorganic perovskites have attracted considerable attention and experienced an exponential growth, with photovoltaic efficiencies as of today reaching above 22%. Despite such an impressive development, some key scientific issues of these materials, including the presence of toxic lead, the poor long-term device stability under heat and humidity conditions, and the anomalous hysteresis of the current-voltage curves shown by various solar cell devices, still remain unsolved and constitute an important focus of experimental and theoretical researchers throughout the world. Density functional theory calculations have been successfully applied to exploring structural and electronic properties of semiconductors, complementing the experimental results in search and discovery of novel functional materials. In this review, we summarize the current progress in perovskite photovoltaic materials from a theoretical perspective. We discuss design of lead-free perovskite materials, humidity-induced degradation mechanisms and possible origins for the observed solar cell hysteresis, and assess future research directions for advanced perovskite solar cells based on computational materials design and theoretical understanding of intrinsic properties.展开更多
The Kubelka-Munk revised theory was adopted to derive the mix design theory of high solar reflectance and high emissivity coatings.When the concentration of each colorant is within 20%,and the width of the coating is ...The Kubelka-Munk revised theory was adopted to derive the mix design theory of high solar reflectance and high emissivity coatings.When the concentration of each colorant is within 20%,and the width of the coating is more than 200 μm,each colorant has enough covering power in visible and near-infrared spectral range.It can be assumed that the addition of colorants in coatings can only change the solar spectral absorption ratio rather than solar spectral scattering coefficient.The spectral scattering coefficient of coatings tends to a constant.The spectral absorption-scattering property of each colorant can be characterized through one parameter.The spectral absorption-scattering coefficient of coatings can be calculated with the multivariate linear relationship of each pigment.Moreover,the results can be expanded for high solar reflectivity and high long-wave emissivity coating preparation.The accuracy of Kubelka-Munk revised theory has been tested and verified through comparison between the calculated value and tested value of coating reflectance.展开更多
The selection of photoactive layer materials for organic solar cells(OSCs) is essential for the photoelectric conversion process.It is well known that chlorophyll is an abundant pigment in nature and is extremely valu...The selection of photoactive layer materials for organic solar cells(OSCs) is essential for the photoelectric conversion process.It is well known that chlorophyll is an abundant pigment in nature and is extremely valuable for photosynthesis.However,there is little research on how to improve the efficiency of chlorophyll-based OSCs by matching chlorophyll derivatives with excellent non-fullerene acceptors to form heterojunctions.Therefore in this study we utilize a chlorophyll derivative,Ce_(6)Me_(3),as a donor material and investigate the performance of its heterojunction with acceptor materials.Through density functional theory,the photoelectric performances of acceptors,i ncluding the fullerene derivative PC_(71)BM and the terminal halogenated non-fullerene DTBCIC series,are compared in detail.It is found that DTBCIC-C1 has better planarity,light absorption,electron affinity,charge reorganization energy and charge mobility than others.Ce_(6)Me_(3) has good energy level matching and absorption spectral complementarity with the investigated acceptor molecules and also shows good electron donor properties.Furthermore,the designed Ce_(6)Me_(3)/DTBCIC interfaces have improved charge separation and reorganization rates(K_(CS)/K_(CR)) compared with the Ce_(6)Me_(3)/PC_(71)BM interface.This research provides a theoretical basis for the design of photoactive layer materials for chlorophyll-based OSCs.展开更多
A series of dye molecules was designed theoretically.Particularly,azoles and their derivatives were chosen as the modifying groups linking to ancillary ligands of [Ru(dcbpyH2)2(NCS)2](N3,dcbpy=4,4'-dicarboxy2,2...A series of dye molecules was designed theoretically.Particularly,azoles and their derivatives were chosen as the modifying groups linking to ancillary ligands of [Ru(dcbpyH2)2(NCS)2](N3,dcbpy=4,4'-dicarboxy2,2'-bipyridine;NCS=thiocyanato).Density functional theory(DFT) based approaches were applied to exploring the electronic structures and properties of all these systems.The dye molecule with 1,2,4-triazole groups which exhibits a very high intensity of absorption in visible region,was obtained.Time-dependent DFT(TD-DFT) results indicate that the ancillary ligand dominates the molecular orbital(MO) energy levels and masters the absorption transition nature to a certain extent.The deprotonation of anchoring ligand not only affects the frontier MO energy levels but also controls the energy gaps of the highest occupied MO(HOMO) to the lowest unoccupied MO(LUMO) and LUMO to LUMO+1 orbital.If the gap between LUMO-LUMO+1 is small enough,the higher efficiency of dye-sensitized solar cell(DSSC) should be expected.展开更多
In recent years some interrelationships between time of birth and longevity were published. Concomitant publications appeared demonstrating links between Space Weather and the timing of medical events;in part of both ...In recent years some interrelationships between time of birth and longevity were published. Concomitant publications appeared demonstrating links between Space Weather and the timing of medical events;in part of both these studies it was shown that Space Weather indices are stronger connected with the time of conception as with the birth time. The aim of these study was to consider birth and conception month of patients suffering from a number of “big killer” pathologies, affecting human longevity and comparing with published data on centenarians—100 - 112 years old persons in the USA. Patients and Methods: We included monthly births distribution of our four papers including patients with Acute Myocardial Infarction undergoing Percutaneous Coronary Intervention (PCI)—n-3765, and admitted in another tertiary medical facility for AMI—n-22,047, and, also patients suffering Rapid—n-1239 and Sudden Cardiac Death—n-327 and, also, patients with oncologic malignancies—n-44587. At all in this group 71,965 patients were included. Their birth and conception months were compared with analogical data of 1574 people of 100 - 112 years old using data of L.A. and N.S. Gavrilov for USA centenarians. Results: The birth months of the cardiovascular and oncology patients were maximal in January, March and April (above 10% at each of these months);their conception was maximal in April, June and July. The monthly distribution of conception and birth of the studied population is presented in Tables 1-3. The maximal birth months of the centenarians were November, September, and October;the maximal conception months were December, January, and February. Conclusion: People suffering Myocardial Infarction, Sudden Cardiac Death and Oncologic Malignancies are in higher numbers born in the first four months of the year and conception in April, June and July. The maximal birth months of the very old people were November, September and October and conception were December, January and February.展开更多
The result of mathematical and physical analysis of the daily change in gravity is presented. The subject of consideration was the manifestation of semi-daily factors in diurnal variations of gravity. The assumption i...The result of mathematical and physical analysis of the daily change in gravity is presented. The subject of consideration was the manifestation of semi-daily factors in diurnal variations of gravity. The assumption is investigated, according to which the cause of the half-day factors is the gravitational shielding of the planet Earth. Gravitational shielding is considered as a function of the size and thickness of celestial bodies and growing with distance from their poles. It is concluded that the planet Earth has the property of partial gravitational shielding, and the Moon does not have enough thickness to exhibit a tangible gravitational shielding. The obtained mathematical results correspond to the existing experimental data. It is suggested that gravitational shielding is the cause of the precession of the perihelion of Mercury and the peculiarities of the manifestation of tidal processes. It is assumed that gravitational shielding is one of the main reasons for the presence of hidden substances in the Universe. It is concluded that the physical picture with mutual shielding of interaction elements corresponds to the classical ideas of Fatio and Lesage. This approach is proposed as an alternative point of view to the existing theory on the description of tidal processes. It is shown that the existing basic approach to the description of tidal forces is unsatisfactory: the factors underlying the existing approaches have values 10 times less than those observed and cannot be considered as the reason for the manifestation of half-day manifestations in the daily change in gravity. The work is a continuation of the implementation by the author of P. Dirac’s ideas about accounting for the size of microparticles in physical theory.展开更多
The structural, electronic, and optical properties of Cu2Zn1−xBaxSn1−ySiyS4 compounds have been calculated using GGA-PBE function within the framework of Density Functional Theory (DFT). In the present work, lattice p...The structural, electronic, and optical properties of Cu2Zn1−xBaxSn1−ySiyS4 compounds have been calculated using GGA-PBE function within the framework of Density Functional Theory (DFT). In the present work, lattice parameters remained the same, that is tetragonal crystal structure for 0% and 100% doping concentration. The electronic band gap of Cu2Zn1−xBaxSn1−ySiyS4 compounds has been gradually increased for continuous increment of doping concentration where the highest electronic band gap is 1.117 eV for Cu2BaSiS4 structure. Moreover, the band gap changes from direct to indirect band gap with the increase of doping concentration in the parent compound. The absorption coefficient has been found to be high (> 104 cm−1) in UV-region for all the doping concentration which makes the studied compound as a potential candidate of absorber layer in the UV detector. The theoretical study of the effect of double doping in the CZTS compound is very interesting for improving the quality of it and it would be a reference for the theoretical and experimental researchers.展开更多
In order to obtain high efficiency of organic light-emitting diodes and organic solar cells,a series of DPP-based four-coordinate organoboron compounds have been designed for photoelectric functional materials.The eff...In order to obtain high efficiency of organic light-emitting diodes and organic solar cells,a series of DPP-based four-coordinate organoboron compounds have been designed for photoelectric functional materials.The effects of electron-donating and-withdrawing substituent on the electronic and optical properties have been investigated by using density functional theory(DFT)and time-dependent DFT(TD-DFT)approaches systematically.It turned out that electron-donating and-withdrawing groups can tune effectively the frontier molecular orbital(FMO)energy level,energy gap,and absorption and fluorescence spectra.The introduction of electron-withdrawing groups for the parent molecule HBDPP(2,5-bis(diphenylboryl)-3,6-bis(pyridin-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione)favors the decrease for the FMO energy(E_(LUMO)and E_(HOMO)),HOMO-LUMO gaps(E_(g)),and the downhill energetic driving force(ΔEL-L),while the electron-donating groups can increase E_(LUMO),E_(HOMO),E_(g),andΔEL-L compared with that of HBDPP,respectively.The absorption and fluorescence spectra of the electron-withdrawing substituted derivatives exhibit bathochromic shifts,while the absorption and fluorescence spectra of the electrondonating substituted derivatives show hypsochromic shifts compared with the parent molecule HBDPP,respectively.Furthermore,the stronger the electron-withdrawing/donating ability of group is,the more significant the effect in the optoelectronic properties.展开更多
Descriptions of unusually high waves appearing on the sea surface for a short time (freak, rogue or killer waves) have been considered as a part of marine folklore for a long time. A number of instrumental registratio...Descriptions of unusually high waves appearing on the sea surface for a short time (freak, rogue or killer waves) have been considered as a part of marine folklore for a long time. A number of instrumental registrations have appeared recently making the community to pay more attention to this problem and to reconsider known observations of freak waves. To allow a better understanding of the behavior of rogue waves associated with tornadoes in terms of their origin, the nonlinear theory of off-balance systems is developed in the specific case of strong agitations constantly seen on the surface of extensive and deep rivers, when they are crossed by an atmosphere’s low pressure system (tornadoes, cyclones, hurricanes, etc.). A mathematical model based on the Navier-Stokes and Euler Lagrange equations coupled with assumptions derived from instrumental registrations on the training locations (or birth places) of freak waves is developed to enhance the physics of processes responsible for the formation (or origin) of the waves associated with atmosphere’s low pressure systems. Freak waves births’ constraints are mainly the need for both consistent water (i.e., extensive-deep rivers) and potential velocity flow availabilities. Numerical simulations, based on the use of the NLSE (Nonlinear Schrodinger Equation) are performed to validate our mathematical model on the births of single carrier waves associated with atmosphere’s low pressure systems.展开更多
The III–V alloys and doping to tune the bandgap for solar cells and other optoelectronic devices has remained a hot topic of research for the last few decades.In the present article,the bandgap tuning and its influen...The III–V alloys and doping to tune the bandgap for solar cells and other optoelectronic devices has remained a hot topic of research for the last few decades.In the present article,the bandgap tuning and its influence on optical properties of In1-xGaxN/P,where(x=0.0,0.25,0.50,0.75,and 1.0)alloys are comprehensively analyzed by density functional theory based on full-potential linearized augmented plane wave method(FP-LAPW)and modified Becke and Johnson potentials(TB-mBJ).The direct bandgaps turn from 0.7 eV to 3.44 eV,and 1.41 eV to 2.32 eV for In1-xGaxN/P alloys,which increases their potentials for optoelectronic devices.The optical properties are discussed such as dielectric constants,refraction,absorption,optical conductivity,and reflection.The light is polarized in the low energy region with minimum reflection.The absorption and optical conduction are maxima in the visible region,and they are shifted into the ultraviolet region by Ga doping.Moreover,static dielectric constant e1(0)is in line with the bandgap from Penn’s model.展开更多
This is a fresh perspective on the sun that considers its huge spherical size in relation to the finite speed of light. The sun is so extended that it takes light approximately 2.32 seconds to travel from the plane of...This is a fresh perspective on the sun that considers its huge spherical size in relation to the finite speed of light. The sun is so extended that it takes light approximately 2.32 seconds to travel from the plane of the solar limb to the plane tangential to the sun at the solar disc’s center. The aforementioned information is utilized in this study to support the new viewpoints. Firstly, it is shown that the solar disc is a simultaneous view of successively emitted coaxial spherical circles. Secondly, despite the fact that the sun is gaseous, it is thought to revolve completely as a rigid body at a fixed angular speed, yet an observer on Earth sees it rotate differentially. In a simple mathematical approach, it is found that the sun’s rotational speed apparently decreases with latitude. Thirdly, a qualitative examination of how we observe simultaneous whole-surface brightness changes of the sun and sunlike stars indicates that such changes would appear to spread out radially from the center of the solar disc.展开更多
The flat-plate solar collector is an important component in solar-thermal systems,and its heat transfer optimization is of great significance in terms of the efficiency of energy utilization.However,most existing flat...The flat-plate solar collector is an important component in solar-thermal systems,and its heat transfer optimization is of great significance in terms of the efficiency of energy utilization.However,most existing flat-plate collectors adopt metallic absorber plates with uniform thickness,which often works against energy conservation.In this paper,to achieve the optimal heat transfer performance,we optimized the thickness distribution of the absorber with the constraint of fixed total material volume employing entransy theory.We first established the correspondence between the collector efficiency and the loss of entransy,and then proposed the constrained extreme-value problem and deduced the optimization criterion,namely a uniform temperature gradient,employing a variational method.Finally,on the basis of the optimization criterion,we carried out numerical simulations,with the results showing remarkable optimization effects.When irradiation,the ambient temperature and the wind speed are 800 W/m2,300 K and 3 m/s,respectively,the collector efficiency is enhanced by 8.8% through optimization,which is equivalent to a copper saving of 30%.We also applied the thickness distribution optimized for wind speed of 3 m/s in heat transfer analysis with different wind speed conditions,and the collector efficiency was remarkably better than that for an absorber with uniform thickness.展开更多
In contrast to a traditional coal-fired power generation plant where steam extracted from a turbine is used to preheat the feedwater in all preheating stages, a solar-aided power generation(SAPG) plant uses solar heat...In contrast to a traditional coal-fired power generation plant where steam extracted from a turbine is used to preheat the feedwater in all preheating stages, a solar-aided power generation(SAPG) plant uses solar heat to replace a part or all of the extracted steam in one or more preheating stages. The performance of an SAPG plant with different replacements is investigated in this study by using specific consumption theory(SCT). Fuel-specific and cost-specific consumption models for SAPG plants are built based on the SCT. A typical 330 MW coal-fired power plant is used as the study case. The performance of the SAPG plant in terms of specific consumption, with steam obtained from the first through the eighth(except for the fourth) stages of extraction replaced by solar heat, is compared with that of the reference coal-fired power plant. The fuel-specific consumption of the SAPG plant is determined to be lower than that of the reference coal-fired power plant. The fuel-specific consumption accrual distribution in SAPG plants is used to assess the effect of each individual replacement. Effective strategies to reduce the specific costs of the SAPG and coal-fired power plants are proposed based on the results of this study.展开更多
文摘American Hollywood animated films have conquered the world.In recent years,many successful works have appeared in domestic animated films,bringing new vitality to the Chinese animated film industry.Based on Lacan’s Mirror Stage Theory,this study attempts to start from the bravery of Judy and Nezha,the protagonists of Zootopia(2016)and Nezha(2019).It analyzes and compares their embodiment,formation,influence and reflection with real society to solve the problems of the two brave characters’formation causes,characteristic differences and social influences,including racial discrimination,individualism in American society and family problems in Chinese society.This study sheds light on the transmission of intercultural values in animated films.
文摘According to the classical mechanics the energy of a celestial body circulating in the solar system is a constant term. This energy is defined by the masses product of the larger and smaller body entering into a mutual attraction as well as the size of the major semiaxis characteristic for the corresponding Kepler orbit. A special situation concerns the planet interaction with the Sun because of a systematic decrease of the Sun mass due to the luminosity effect. The aim of the paper is to point out that even in the case of perfectly constant interacting masses the energy of the moving body should decrease when a quantum treatment of the body motion is considered. The rate of the energy decrease is extremely small, nevertheless it gives a shortening of the distance between the interacting bodies leading to a final effect of a touch of the larger body and a smaller one.
文摘The performances of turbine blades have a significant impact on the energy conversion efficiency of vertical solar power plants.In the present study,such a relationship is assessed by considering two kinds of airfoil blades,designed by using the Wilson theory.In particular,numerical simulations are conducted using the SST K−ω model and assuming a wind speed of 3–6 m/s and seven or eight blades.The two airfoils are the NACA63121(with a larger chord length)and the AMES63212;It is shown that the torsion angle of the former is smaller,and its wind drag ratio is larger;furthermore,the resistance is increased by about 66.3%on average.Within the scope of the study,the results show that the NACA63212 airfoil is better than the AMES63212 airfoil in terms of power,with an average improvement of about 2.8%.The simulation results have a certain guiding significance for selecting turbine blade airfoils and improving turbine efficiency.
文摘Time and environmental physical activity are involved in timing of many medical events. In a recent study published by the National Academy of Science, USA it was shown that month of birth is related to longevity. The aim of this study was to check the month of birth distribution in a great group of AMI patients of both gender, one of the great killers in the developed countries, to check the mentioned paradigm of month of birth and longevity. Methods & Patients: Patients admitted to Cardiology Departments of a tertiary University Hospital in Kaunas, Lithuania with AMI at years 1990-2010 (n-22047) were studied. Month of birth of these patients, total and both gender were checked. Monthly, quarterly and trimester comparison were done. Statistical differences established using t-Student test and distribution by percents of the yearly months of birth. Results: It was a significant difference in the month of birth of the studied AMI population. January and first quarter and trimester born patients were more often in the studied AMI patients group. The higher morbidity by Cardiovascular diseases can be a significant ingredient in the structure of population longevity. Possible mechanisms explaining our findings are discussed. Conclusion: In the AMI population people born in January, first quarter or trimester of the year are dominating in both gender groups. The results of this study can be an additional confirmation of the paradigm about links between month of birth and longevity.
基金Supported by Innovation Program of Shanghai Municipal Education Commission(09YZ229)Leading Academic Discipline Project of Shanghai Municipal Education Commission(J50502)+2 种基金Fund of National Natural Science Foundation of China(30771245)National Natural Science Foundation of China(50478113)the specific project for the Shanghai World Expo with main scientific and technology(06dz05809)
文摘Based on the similarity theory,a scale effect model of the spraying water cooling system of Shanghai expo Theme Pavilion's roof was set up.According to the typical weather conditions in Shanghai city,different models were analyzed on solar radiation,and different heat transfer amount was obtained.And the following conclusions could be made:At the sunny day of summer in Shanghai,the temperature of inner roof with sprinkling system descended about 3 ℃,and the air conditioning load of the whole Theme Pavilion descend more than 320 kW.
基金Financial support provided by the National Natural Science Foundation of China (Grant No. 51402036, 21373042)International Science & Technology Cooperation Program of China (Grant No. 2013DFA51000)+1 种基金the Fundamental Research Funds for the Central Universities (Grant No. DUT15YQ109)supported by the State Key Laboratory of Fine Chemicals of China
文摘For some specific catalytic reaction, how to construct active sites on two dimensional materials is of great scientific significance. Dye-sensitized solar cells(DSCs) can be viewed as one representative photovoltaics because in which liquid electrolyte with triiodide/iodide(I;/I;) as redox couples are involved. In this study, amino-functionalized graphene(AFG) has been designed according to theoretically analyzing iodine reduction reaction(IRR) processes and rationally screening the volcanic plot. Then, such AFG has been successfully synthesized by a simple hydrothermal method and shows high electrocatalytic activity towards IRR when serving as counter electrode in DSCs. Finally, a high conversion efficiency of 7.39% by AFG-based DSCs was obtained, which is close to that using Pt as counter electrode.
文摘A recent development in climate research is the recognition that space activity such as solar flares, gamma ray bursts, supernovas etc. can have a significant impact on the Earth. The existing methods of modelling space activity do not model these phenomena explicitly. Instead, their effect on ionization rates is formulated and then built into existing climate models. In this paper, based on the authors’ earlier work, several analytical approaches for modelling a solar flare hitting the Earth are presented. These methods can also be used for modelling gamma-ray bursts or cosmic rays striking our planet. In addition, a method of calculating the total amount of radiation received during a solar flare is proposed. The future use of the proposed modelling approaches within comprehensive global climate models allows for explicit modelling of space activity and provides a new pathway for studying the possible effects of this activity on the Earth.
基金support of the National Natural Science Foundation of China,grant nos.21473183 and 21303079the Foundation for Polish Science,grant no.42.2016,for support through the START 2016 program+1 种基金US National Science Foundation,grant no.CHE-1565704US Department of Energy,grant no.DE-SC0014429,for financial support
文摘Since the seminal work by Kojima et al. in 2009, solar cells based on hybrid organic-inorganic perovskites have attracted considerable attention and experienced an exponential growth, with photovoltaic efficiencies as of today reaching above 22%. Despite such an impressive development, some key scientific issues of these materials, including the presence of toxic lead, the poor long-term device stability under heat and humidity conditions, and the anomalous hysteresis of the current-voltage curves shown by various solar cell devices, still remain unsolved and constitute an important focus of experimental and theoretical researchers throughout the world. Density functional theory calculations have been successfully applied to exploring structural and electronic properties of semiconductors, complementing the experimental results in search and discovery of novel functional materials. In this review, we summarize the current progress in perovskite photovoltaic materials from a theoretical perspective. We discuss design of lead-free perovskite materials, humidity-induced degradation mechanisms and possible origins for the observed solar cell hysteresis, and assess future research directions for advanced perovskite solar cells based on computational materials design and theoretical understanding of intrinsic properties.
基金Supported by the 12th Five-year National Science and Technology Support Plan(No.2011BAE27B04)the Natural Science Foundation of China(No.51378391)the China Scholarship Council(award to HE Yan for studying in the University of Toronto)
文摘The Kubelka-Munk revised theory was adopted to derive the mix design theory of high solar reflectance and high emissivity coatings.When the concentration of each colorant is within 20%,and the width of the coating is more than 200 μm,each colorant has enough covering power in visible and near-infrared spectral range.It can be assumed that the addition of colorants in coatings can only change the solar spectral absorption ratio rather than solar spectral scattering coefficient.The spectral scattering coefficient of coatings tends to a constant.The spectral absorption-scattering property of each colorant can be characterized through one parameter.The spectral absorption-scattering coefficient of coatings can be calculated with the multivariate linear relationship of each pigment.Moreover,the results can be expanded for high solar reflectivity and high long-wave emissivity coating preparation.The accuracy of Kubelka-Munk revised theory has been tested and verified through comparison between the calculated value and tested value of coating reflectance.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12074059, 11974152, and 11404055)Heilongjiang Postdoctoral Fund (Grant No. LBH-Q21061)。
文摘The selection of photoactive layer materials for organic solar cells(OSCs) is essential for the photoelectric conversion process.It is well known that chlorophyll is an abundant pigment in nature and is extremely valuable for photosynthesis.However,there is little research on how to improve the efficiency of chlorophyll-based OSCs by matching chlorophyll derivatives with excellent non-fullerene acceptors to form heterojunctions.Therefore in this study we utilize a chlorophyll derivative,Ce_(6)Me_(3),as a donor material and investigate the performance of its heterojunction with acceptor materials.Through density functional theory,the photoelectric performances of acceptors,i ncluding the fullerene derivative PC_(71)BM and the terminal halogenated non-fullerene DTBCIC series,are compared in detail.It is found that DTBCIC-C1 has better planarity,light absorption,electron affinity,charge reorganization energy and charge mobility than others.Ce_(6)Me_(3) has good energy level matching and absorption spectral complementarity with the investigated acceptor molecules and also shows good electron donor properties.Furthermore,the designed Ce_(6)Me_(3)/DTBCIC interfaces have improved charge separation and reorganization rates(K_(CS)/K_(CR)) compared with the Ce_(6)Me_(3)/PC_(71)BM interface.This research provides a theoretical basis for the design of photoactive layer materials for chlorophyll-based OSCs.
基金Supported by the National Natural Science Foundation of China(Nos.20973076,21003057)the Specialized Research Fund for the Doctoral Program of Higher Education,China(No.20110061110018)
文摘A series of dye molecules was designed theoretically.Particularly,azoles and their derivatives were chosen as the modifying groups linking to ancillary ligands of [Ru(dcbpyH2)2(NCS)2](N3,dcbpy=4,4'-dicarboxy2,2'-bipyridine;NCS=thiocyanato).Density functional theory(DFT) based approaches were applied to exploring the electronic structures and properties of all these systems.The dye molecule with 1,2,4-triazole groups which exhibits a very high intensity of absorption in visible region,was obtained.Time-dependent DFT(TD-DFT) results indicate that the ancillary ligand dominates the molecular orbital(MO) energy levels and masters the absorption transition nature to a certain extent.The deprotonation of anchoring ligand not only affects the frontier MO energy levels but also controls the energy gaps of the highest occupied MO(HOMO) to the lowest unoccupied MO(LUMO) and LUMO to LUMO+1 orbital.If the gap between LUMO-LUMO+1 is small enough,the higher efficiency of dye-sensitized solar cell(DSSC) should be expected.
文摘In recent years some interrelationships between time of birth and longevity were published. Concomitant publications appeared demonstrating links between Space Weather and the timing of medical events;in part of both these studies it was shown that Space Weather indices are stronger connected with the time of conception as with the birth time. The aim of these study was to consider birth and conception month of patients suffering from a number of “big killer” pathologies, affecting human longevity and comparing with published data on centenarians—100 - 112 years old persons in the USA. Patients and Methods: We included monthly births distribution of our four papers including patients with Acute Myocardial Infarction undergoing Percutaneous Coronary Intervention (PCI)—n-3765, and admitted in another tertiary medical facility for AMI—n-22,047, and, also patients suffering Rapid—n-1239 and Sudden Cardiac Death—n-327 and, also, patients with oncologic malignancies—n-44587. At all in this group 71,965 patients were included. Their birth and conception months were compared with analogical data of 1574 people of 100 - 112 years old using data of L.A. and N.S. Gavrilov for USA centenarians. Results: The birth months of the cardiovascular and oncology patients were maximal in January, March and April (above 10% at each of these months);their conception was maximal in April, June and July. The monthly distribution of conception and birth of the studied population is presented in Tables 1-3. The maximal birth months of the centenarians were November, September, and October;the maximal conception months were December, January, and February. Conclusion: People suffering Myocardial Infarction, Sudden Cardiac Death and Oncologic Malignancies are in higher numbers born in the first four months of the year and conception in April, June and July. The maximal birth months of the very old people were November, September and October and conception were December, January and February.
文摘The result of mathematical and physical analysis of the daily change in gravity is presented. The subject of consideration was the manifestation of semi-daily factors in diurnal variations of gravity. The assumption is investigated, according to which the cause of the half-day factors is the gravitational shielding of the planet Earth. Gravitational shielding is considered as a function of the size and thickness of celestial bodies and growing with distance from their poles. It is concluded that the planet Earth has the property of partial gravitational shielding, and the Moon does not have enough thickness to exhibit a tangible gravitational shielding. The obtained mathematical results correspond to the existing experimental data. It is suggested that gravitational shielding is the cause of the precession of the perihelion of Mercury and the peculiarities of the manifestation of tidal processes. It is assumed that gravitational shielding is one of the main reasons for the presence of hidden substances in the Universe. It is concluded that the physical picture with mutual shielding of interaction elements corresponds to the classical ideas of Fatio and Lesage. This approach is proposed as an alternative point of view to the existing theory on the description of tidal processes. It is shown that the existing basic approach to the description of tidal forces is unsatisfactory: the factors underlying the existing approaches have values 10 times less than those observed and cannot be considered as the reason for the manifestation of half-day manifestations in the daily change in gravity. The work is a continuation of the implementation by the author of P. Dirac’s ideas about accounting for the size of microparticles in physical theory.
文摘The structural, electronic, and optical properties of Cu2Zn1−xBaxSn1−ySiyS4 compounds have been calculated using GGA-PBE function within the framework of Density Functional Theory (DFT). In the present work, lattice parameters remained the same, that is tetragonal crystal structure for 0% and 100% doping concentration. The electronic band gap of Cu2Zn1−xBaxSn1−ySiyS4 compounds has been gradually increased for continuous increment of doping concentration where the highest electronic band gap is 1.117 eV for Cu2BaSiS4 structure. Moreover, the band gap changes from direct to indirect band gap with the increase of doping concentration in the parent compound. The absorption coefficient has been found to be high (> 104 cm−1) in UV-region for all the doping concentration which makes the studied compound as a potential candidate of absorber layer in the UV detector. The theoretical study of the effect of double doping in the CZTS compound is very interesting for improving the quality of it and it would be a reference for the theoretical and experimental researchers.
基金the National Natural Science Foundation of China(21563002)the Natural Science Foundation of Inner Mongolia Autonomous Region(2021LHMS02001)the Research Program of Sciences at Universities of Inner Mongolia Autonomous Region(NJZY21175)
文摘In order to obtain high efficiency of organic light-emitting diodes and organic solar cells,a series of DPP-based four-coordinate organoboron compounds have been designed for photoelectric functional materials.The effects of electron-donating and-withdrawing substituent on the electronic and optical properties have been investigated by using density functional theory(DFT)and time-dependent DFT(TD-DFT)approaches systematically.It turned out that electron-donating and-withdrawing groups can tune effectively the frontier molecular orbital(FMO)energy level,energy gap,and absorption and fluorescence spectra.The introduction of electron-withdrawing groups for the parent molecule HBDPP(2,5-bis(diphenylboryl)-3,6-bis(pyridin-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione)favors the decrease for the FMO energy(E_(LUMO)and E_(HOMO)),HOMO-LUMO gaps(E_(g)),and the downhill energetic driving force(ΔEL-L),while the electron-donating groups can increase E_(LUMO),E_(HOMO),E_(g),andΔEL-L compared with that of HBDPP,respectively.The absorption and fluorescence spectra of the electron-withdrawing substituted derivatives exhibit bathochromic shifts,while the absorption and fluorescence spectra of the electrondonating substituted derivatives show hypsochromic shifts compared with the parent molecule HBDPP,respectively.Furthermore,the stronger the electron-withdrawing/donating ability of group is,the more significant the effect in the optoelectronic properties.
文摘Descriptions of unusually high waves appearing on the sea surface for a short time (freak, rogue or killer waves) have been considered as a part of marine folklore for a long time. A number of instrumental registrations have appeared recently making the community to pay more attention to this problem and to reconsider known observations of freak waves. To allow a better understanding of the behavior of rogue waves associated with tornadoes in terms of their origin, the nonlinear theory of off-balance systems is developed in the specific case of strong agitations constantly seen on the surface of extensive and deep rivers, when they are crossed by an atmosphere’s low pressure system (tornadoes, cyclones, hurricanes, etc.). A mathematical model based on the Navier-Stokes and Euler Lagrange equations coupled with assumptions derived from instrumental registrations on the training locations (or birth places) of freak waves is developed to enhance the physics of processes responsible for the formation (or origin) of the waves associated with atmosphere’s low pressure systems. Freak waves births’ constraints are mainly the need for both consistent water (i.e., extensive-deep rivers) and potential velocity flow availabilities. Numerical simulations, based on the use of the NLSE (Nonlinear Schrodinger Equation) are performed to validate our mathematical model on the births of single carrier waves associated with atmosphere’s low pressure systems.
文摘The III–V alloys and doping to tune the bandgap for solar cells and other optoelectronic devices has remained a hot topic of research for the last few decades.In the present article,the bandgap tuning and its influence on optical properties of In1-xGaxN/P,where(x=0.0,0.25,0.50,0.75,and 1.0)alloys are comprehensively analyzed by density functional theory based on full-potential linearized augmented plane wave method(FP-LAPW)and modified Becke and Johnson potentials(TB-mBJ).The direct bandgaps turn from 0.7 eV to 3.44 eV,and 1.41 eV to 2.32 eV for In1-xGaxN/P alloys,which increases their potentials for optoelectronic devices.The optical properties are discussed such as dielectric constants,refraction,absorption,optical conductivity,and reflection.The light is polarized in the low energy region with minimum reflection.The absorption and optical conduction are maxima in the visible region,and they are shifted into the ultraviolet region by Ga doping.Moreover,static dielectric constant e1(0)is in line with the bandgap from Penn’s model.
文摘This is a fresh perspective on the sun that considers its huge spherical size in relation to the finite speed of light. The sun is so extended that it takes light approximately 2.32 seconds to travel from the plane of the solar limb to the plane tangential to the sun at the solar disc’s center. The aforementioned information is utilized in this study to support the new viewpoints. Firstly, it is shown that the solar disc is a simultaneous view of successively emitted coaxial spherical circles. Secondly, despite the fact that the sun is gaseous, it is thought to revolve completely as a rigid body at a fixed angular speed, yet an observer on Earth sees it rotate differentially. In a simple mathematical approach, it is found that the sun’s rotational speed apparently decreases with latitude. Thirdly, a qualitative examination of how we observe simultaneous whole-surface brightness changes of the sun and sunlike stars indicates that such changes would appear to spread out radially from the center of the solar disc.
基金supported by the National Natural Science Foundation of China (51006060)
文摘The flat-plate solar collector is an important component in solar-thermal systems,and its heat transfer optimization is of great significance in terms of the efficiency of energy utilization.However,most existing flat-plate collectors adopt metallic absorber plates with uniform thickness,which often works against energy conservation.In this paper,to achieve the optimal heat transfer performance,we optimized the thickness distribution of the absorber with the constraint of fixed total material volume employing entransy theory.We first established the correspondence between the collector efficiency and the loss of entransy,and then proposed the constrained extreme-value problem and deduced the optimization criterion,namely a uniform temperature gradient,employing a variational method.Finally,on the basis of the optimization criterion,we carried out numerical simulations,with the results showing remarkable optimization effects.When irradiation,the ambient temperature and the wind speed are 800 W/m2,300 K and 3 m/s,respectively,the collector efficiency is enhanced by 8.8% through optimization,which is equivalent to a copper saving of 30%.We also applied the thickness distribution optimized for wind speed of 3 m/s in heat transfer analysis with different wind speed conditions,and the collector efficiency was remarkably better than that for an absorber with uniform thickness.
基金supported by the National Basic Research Program of China("973"Project)(Grant No.2015CB251505)the National Natural Science Foundation of China(Grant No.51206049)+2 种基金the National Hi-Tech Research and Development Program of China("863"Project)(2012AA050604)the 111 Project(Grant No.B12034)the Fundamental Research Funds for the Central Universities(Grant No.2014XS29)
文摘In contrast to a traditional coal-fired power generation plant where steam extracted from a turbine is used to preheat the feedwater in all preheating stages, a solar-aided power generation(SAPG) plant uses solar heat to replace a part or all of the extracted steam in one or more preheating stages. The performance of an SAPG plant with different replacements is investigated in this study by using specific consumption theory(SCT). Fuel-specific and cost-specific consumption models for SAPG plants are built based on the SCT. A typical 330 MW coal-fired power plant is used as the study case. The performance of the SAPG plant in terms of specific consumption, with steam obtained from the first through the eighth(except for the fourth) stages of extraction replaced by solar heat, is compared with that of the reference coal-fired power plant. The fuel-specific consumption of the SAPG plant is determined to be lower than that of the reference coal-fired power plant. The fuel-specific consumption accrual distribution in SAPG plants is used to assess the effect of each individual replacement. Effective strategies to reduce the specific costs of the SAPG and coal-fired power plants are proposed based on the results of this study.