This paper presents a theoretical design method for a magnetic energy harvesting module. This module consists of an air-core coil and resonant capacitor. With a simple RLC circuit model, it can derive an equation of h...This paper presents a theoretical design method for a magnetic energy harvesting module. This module consists of an air-core coil and resonant capacitor. With a simple RLC circuit model, it can derive an equation of harvesting energy as a function of coil size. In order to demonstrate the magnetic field, a uniform magnetic field is generated by the developed coil system. From the experimented results, it is successfully demonstrated 100 mW of energy harvesting from a magnetic field of 0.09 mT at 60 Hz. This value is in good agreement with the estimated results. Harvested energy is proportional to the square of the magnetic flux density. However, ICNIRP2010 provides a guideline that an acceptable level for human health in a public space is 0.2 mT at power-line frequency. This paper also discuss the possibilities of several applications related with both magnetic energy harvesting and wireless power transmission.展开更多
Composition design of high-entropy carbides is a topic of great scientific interest for the hot-end parts in the aerospace field.A novel theoretical method through an inverse composition design route,i.e.initially ens...Composition design of high-entropy carbides is a topic of great scientific interest for the hot-end parts in the aerospace field.A novel theoretical method through an inverse composition design route,i.e.initially ensuring the oxide scale with excellent anti-ablation stability,is proposed to improve the ablation resistance of the highentropy carbide coatings.In this work,the(Hf_(0.36)Zr_(0.24)Ti_(0.1)Sc_(0.1)Y_(0.1)La_(0.1))C1-δ(HEC)coatings were prepared by the inverse design concept and verified by the ablation resistance experiment.The linear ablation rate of the HEC coatings is1.45μm/s,only 4.78%of the pristine HfC coatings after the oxyacetylene ablation at 4.18 MW/m2.The HEC possesses higher toughness with a higher Pugh's ratio of 1.55 in comparison with HfC(1.30).The in-situ formed dense(Hf_(0.36)Zr_(0.24)Ti_(0.1)Sc_(0.1)Y_(0.1)La_(0.1))O2-δoxide scale during ablation benefits to improve the anti-ablation performance attributed to its high structural adaptability with a lattice constant change not exceeding 0.19%at 2000-2300℃.The current investigation demonstrates the effectiveness of the inverse theoretical design,providing a novel optimization approach for ablation protection of high-entropy carbide coatings.展开更多
Two-dimensional(2D)ferroelectrics(FEs),which maintain stable electric polarization in ultrathin films,are a promising class of materials for the development of various miniature functional devices.In recent years,seve...Two-dimensional(2D)ferroelectrics(FEs),which maintain stable electric polarization in ultrathin films,are a promising class of materials for the development of various miniature functional devices.In recent years,several 2D FEs with unique properties have been successfully fabricated through experiments.They have been found to exhibit some unique properties either by themselves or when they are coupled with other functional materials(e.g.,ferromagnetic materials,materials with 5 d electrons,etc.).As a result,several new types of 2D FE functional devices have been developed,exhibiting excellent performance.As a type of newly discovered 2D functional material,the number of 2D FEs and the exploration of their properties are still limited and this calls for further theoretical predictions.This review summarizes recent progress in the theoretical predictions of 2D FE materials and provides strategies for the rational design of 2D FE materials.The aim of this review is to provide guidelines for the design of 2D FE materials and related functional devices.展开更多
Rock quality designation(RQD)has been considered as a one-dimensional jointing degree property since it should be determined by measuring the core lengths obtained from drilling.Anisotropy index of jointing degree(AI_...Rock quality designation(RQD)has been considered as a one-dimensional jointing degree property since it should be determined by measuring the core lengths obtained from drilling.Anisotropy index of jointing degree(AI_(jd))was formulated by Zheng et al.(2018)by considering maximum and minimum values of RQD for a jointed rock medium in three-dimensional space.In accordance with spacing terminology by ISRM(1981),defining the jointing degree for the rock masses composed of extremely closely spaced joints as well as for the rock masses including widely to extremely widely spaced joints is practically impossible because of the use of 10 cm as a threshold value in the conventional form of RQD.To overcome this limitation,theoretical RQD(TRQD_(t))introduced by Priest and Hudson(1976)can be taken into consideration only when the statistical distribution of discontinuity spacing has a negative exponential distribution.Anisotropy index of the jointing degree was improved using TRQD_(t) which was adjusted to wider joint spacing by considering Priest(1993)’s recommendation on the use of variable threshold value(t)in TRQD_(t) formulation.After applications of the improved anisotropy index of a jointing degree(AI'_(jd))to hypothetical jointed rock mass cases,the effect of persistency of joints on structural anisotropy of rock mass was introduced to the improved AI'_(jd) formulation by considering the ratings of persistency of joints as proposed by Bieniawski(1989)’s rock mass rating(RMR)classification.Two real cases were assessed in the stratified marl and the columnar basalt using the weighted anisotropy index of jointing degree(W_AI'_(jd)).A structural anisotropy classification was developed using the RQD classification proposed by Deere(1963).The proposed methodology is capable of defining the structural anisotropy of a rock mass including joint pattern from extremely closely to extremely widely spaced joints.展开更多
Evaluated Weather Research and Forecasting model inline with chemistry (WRF/Chem) simulations of the 2009 Crazy Mountain Complex wildfire in Interior Alaska served as a testbed for typical Alaska wildfire-smoke condit...Evaluated Weather Research and Forecasting model inline with chemistry (WRF/Chem) simulations of the 2009 Crazy Mountain Complex wildfire in Interior Alaska served as a testbed for typical Alaska wildfire-smoke conditions. A virtual unmanned air vehicle (UAV) sampled temperatures, dewpoint temperatures, primary inert and reactive gases and particular matter of different sizes as well as secondary pollutants from the WRF/Chem results using different sampling patterns, altitudes and speeds to investigate the impact of the sampling design on obtained mean distributions. In this experimental design, the WRF/Chem data served as the “grand truth” to assess the mean distributions from sampling. During frontal passage, the obtained mean distributions were sensitive to the flight patterns, speeds and heights. For inert constituents mean distributions from sampling agreed with the “grand truth” within a factor of two at 1000 m. Mean distributions of gases involved in photochemistry differed among flight patterns except for ozone. The diurnal cycle of these gases’ concentrations led to overestimation (underestimation) of 20 h means in areas of high (low) concentrations as compared to the “grand truth.” The mean ozone distribution was sensitive to the speed of the virtual UAV. Particulate matter showed the strongest sensitivity to the flight patterns, especially during precipitation.展开更多
A reasonably-thick GaNAs/GalnAs superlattice could be an option as a roughly 1 eV subcell to achieve high-effiCiency multi-junction solar cells on a lattice-matched Ge substrate. A detailed consideration of a high- ef...A reasonably-thick GaNAs/GalnAs superlattice could be an option as a roughly 1 eV subcell to achieve high-effiCiency multi-junction solar cells on a lattice-matched Ge substrate. A detailed consideration of a high- efficiency design for a GaInP/GaAs/1 eV/Ge device is presented. Calculations have been done for this structure to obtain the confined energies of the electrons and holes by utilizing the Kronig-Penney model, as well as the absorption coefficient and thereby the external quantum efficiency. The effect of well layers, GaNAs or GaInAs, on the absorption and photocurrent density under the AM 1.5 condition is discussed in order to realize a requirement of current matching in the four-junction solar cells. The management of these considerations implies the feasibility of the GaNAs/GaInAs superlattice subcell design to improve the overall conversion efficiency of lattice matched GaInP/GaAs/1 eV/Ge cells.展开更多
The human social development saw the formation of five unique civilizations,with the latter forming their own distinctive cultures.China’s traditional culture is its most fundamental ideological weapon for solving pr...The human social development saw the formation of five unique civilizations,with the latter forming their own distinctive cultures.China’s traditional culture is its most fundamental ideological weapon for solving problems.The Chinese are good at comprehensive thinking,dialectical thinking,and systematic analysis.These ideological weapons can solve the problems of formal science and technology and create scientific and technological achievements on par with global advanced scale.Ancient China is filled with original scientific and technological achievements,which strongly prove ancient China’s possession of its own science and technology different from that of Western Renaissance.Therefore,a comprehensive understanding of science,technology,experience,and intuition is necessary.The long-held superstition regarding the West,the lack of confidence,self-denial,blind imitation of ideas,and shackles must be thrown away.Only then can we take the road toward an authentic Chinese creative design as we learn from others.展开更多
文摘This paper presents a theoretical design method for a magnetic energy harvesting module. This module consists of an air-core coil and resonant capacitor. With a simple RLC circuit model, it can derive an equation of harvesting energy as a function of coil size. In order to demonstrate the magnetic field, a uniform magnetic field is generated by the developed coil system. From the experimented results, it is successfully demonstrated 100 mW of energy harvesting from a magnetic field of 0.09 mT at 60 Hz. This value is in good agreement with the estimated results. Harvested energy is proportional to the square of the magnetic flux density. However, ICNIRP2010 provides a guideline that an acceptable level for human health in a public space is 0.2 mT at power-line frequency. This paper also discuss the possibilities of several applications related with both magnetic energy harvesting and wireless power transmission.
基金supported by the National Key R&D Program of China(2022YFB3708600,2021YFA0715802)Aeronautical Science Foundation of China(2022Z055053004)+1 种基金Fund of Key Laboratory of National Defense Science and Technology(WDZC20235250505)National Major Science and Technology Projects of China(J2022-VI-0011-0042).
文摘Composition design of high-entropy carbides is a topic of great scientific interest for the hot-end parts in the aerospace field.A novel theoretical method through an inverse composition design route,i.e.initially ensuring the oxide scale with excellent anti-ablation stability,is proposed to improve the ablation resistance of the highentropy carbide coatings.In this work,the(Hf_(0.36)Zr_(0.24)Ti_(0.1)Sc_(0.1)Y_(0.1)La_(0.1))C1-δ(HEC)coatings were prepared by the inverse design concept and verified by the ablation resistance experiment.The linear ablation rate of the HEC coatings is1.45μm/s,only 4.78%of the pristine HfC coatings after the oxyacetylene ablation at 4.18 MW/m2.The HEC possesses higher toughness with a higher Pugh's ratio of 1.55 in comparison with HfC(1.30).The in-situ formed dense(Hf_(0.36)Zr_(0.24)Ti_(0.1)Sc_(0.1)Y_(0.1)La_(0.1))O2-δoxide scale during ablation benefits to improve the anti-ablation performance attributed to its high structural adaptability with a lattice constant change not exceeding 0.19%at 2000-2300℃.The current investigation demonstrates the effectiveness of the inverse theoretical design,providing a novel optimization approach for ablation protection of high-entropy carbide coatings.
基金financial support from National Natural Science Foundation of China(52250402 and 61888102)Strategic Priority Research Program of the Chinese Academy of Sciences(XDB30000000 and XDB28000000)+1 种基金CAS Project for Young Scientists in Basic Research(YSBR-003)the Fundamental Research Funds for the Central Universities.
文摘Two-dimensional(2D)ferroelectrics(FEs),which maintain stable electric polarization in ultrathin films,are a promising class of materials for the development of various miniature functional devices.In recent years,several 2D FEs with unique properties have been successfully fabricated through experiments.They have been found to exhibit some unique properties either by themselves or when they are coupled with other functional materials(e.g.,ferromagnetic materials,materials with 5 d electrons,etc.).As a result,several new types of 2D FE functional devices have been developed,exhibiting excellent performance.As a type of newly discovered 2D functional material,the number of 2D FEs and the exploration of their properties are still limited and this calls for further theoretical predictions.This review summarizes recent progress in the theoretical predictions of 2D FE materials and provides strategies for the rational design of 2D FE materials.The aim of this review is to provide guidelines for the design of 2D FE materials and related functional devices.
基金supports from the General Directorate of ETIMADEN enterprises during the field studies at Simav open pit mine。
文摘Rock quality designation(RQD)has been considered as a one-dimensional jointing degree property since it should be determined by measuring the core lengths obtained from drilling.Anisotropy index of jointing degree(AI_(jd))was formulated by Zheng et al.(2018)by considering maximum and minimum values of RQD for a jointed rock medium in three-dimensional space.In accordance with spacing terminology by ISRM(1981),defining the jointing degree for the rock masses composed of extremely closely spaced joints as well as for the rock masses including widely to extremely widely spaced joints is practically impossible because of the use of 10 cm as a threshold value in the conventional form of RQD.To overcome this limitation,theoretical RQD(TRQD_(t))introduced by Priest and Hudson(1976)can be taken into consideration only when the statistical distribution of discontinuity spacing has a negative exponential distribution.Anisotropy index of the jointing degree was improved using TRQD_(t) which was adjusted to wider joint spacing by considering Priest(1993)’s recommendation on the use of variable threshold value(t)in TRQD_(t) formulation.After applications of the improved anisotropy index of a jointing degree(AI'_(jd))to hypothetical jointed rock mass cases,the effect of persistency of joints on structural anisotropy of rock mass was introduced to the improved AI'_(jd) formulation by considering the ratings of persistency of joints as proposed by Bieniawski(1989)’s rock mass rating(RMR)classification.Two real cases were assessed in the stratified marl and the columnar basalt using the weighted anisotropy index of jointing degree(W_AI'_(jd)).A structural anisotropy classification was developed using the RQD classification proposed by Deere(1963).The proposed methodology is capable of defining the structural anisotropy of a rock mass including joint pattern from extremely closely to extremely widely spaced joints.
基金The National Aeronautics and Space Administration provided funding(Grant NASA-NNX11AQ27A).
文摘Evaluated Weather Research and Forecasting model inline with chemistry (WRF/Chem) simulations of the 2009 Crazy Mountain Complex wildfire in Interior Alaska served as a testbed for typical Alaska wildfire-smoke conditions. A virtual unmanned air vehicle (UAV) sampled temperatures, dewpoint temperatures, primary inert and reactive gases and particular matter of different sizes as well as secondary pollutants from the WRF/Chem results using different sampling patterns, altitudes and speeds to investigate the impact of the sampling design on obtained mean distributions. In this experimental design, the WRF/Chem data served as the “grand truth” to assess the mean distributions from sampling. During frontal passage, the obtained mean distributions were sensitive to the flight patterns, speeds and heights. For inert constituents mean distributions from sampling agreed with the “grand truth” within a factor of two at 1000 m. Mean distributions of gases involved in photochemistry differed among flight patterns except for ozone. The diurnal cycle of these gases’ concentrations led to overestimation (underestimation) of 20 h means in areas of high (low) concentrations as compared to the “grand truth.” The mean ozone distribution was sensitive to the speed of the virtual UAV. Particulate matter showed the strongest sensitivity to the flight patterns, especially during precipitation.
基金supported by the National Natural Science Foundation of China(No.61274134)the International Cooperation Program of SuzhouChina(No.SH201215)
文摘A reasonably-thick GaNAs/GalnAs superlattice could be an option as a roughly 1 eV subcell to achieve high-effiCiency multi-junction solar cells on a lattice-matched Ge substrate. A detailed consideration of a high- efficiency design for a GaInP/GaAs/1 eV/Ge device is presented. Calculations have been done for this structure to obtain the confined energies of the electrons and holes by utilizing the Kronig-Penney model, as well as the absorption coefficient and thereby the external quantum efficiency. The effect of well layers, GaNAs or GaInAs, on the absorption and photocurrent density under the AM 1.5 condition is discussed in order to realize a requirement of current matching in the four-junction solar cells. The management of these considerations implies the feasibility of the GaNAs/GaInAs superlattice subcell design to improve the overall conversion efficiency of lattice matched GaInP/GaAs/1 eV/Ge cells.
文摘The human social development saw the formation of five unique civilizations,with the latter forming their own distinctive cultures.China’s traditional culture is its most fundamental ideological weapon for solving problems.The Chinese are good at comprehensive thinking,dialectical thinking,and systematic analysis.These ideological weapons can solve the problems of formal science and technology and create scientific and technological achievements on par with global advanced scale.Ancient China is filled with original scientific and technological achievements,which strongly prove ancient China’s possession of its own science and technology different from that of Western Renaissance.Therefore,a comprehensive understanding of science,technology,experience,and intuition is necessary.The long-held superstition regarding the West,the lack of confidence,self-denial,blind imitation of ideas,and shackles must be thrown away.Only then can we take the road toward an authentic Chinese creative design as we learn from others.
