Starting from the characteristics of modernization in three different historical stages since the founding of the People’s Republic of China,this paper analyses the internal changes in the professional name,subordina...Starting from the characteristics of modernization in three different historical stages since the founding of the People’s Republic of China,this paper analyses the internal changes in the professional name,subordinate disciplines and categories,and professional mission of the environmental design profession,and summarizes the changes in the characteristics of the environmental design profession in 10 aspects such as subordinate disciplines,design objects,design types,cultural characteristics,and aesthetic values on the basis of the results of the analysis,and explores five transformations of the environmental design profession in the process of China’s development in the future.The five transformations in the future development of China are to serve the harmony and beauty of the three major urban and rural spaces with“small and micro-renewal and reconstruction”;to serve the transmission of Chinese culture and the spread of Chinese civilization with“spatial heritage and innovation”;to serve the balance and sufficiency of the four functions of urban and rural settlements with“friendliness and equilibrium”;to serve the intelligence,wisdom,and enjoyment of indoor and outdoor living environment space with“scientific and technological achievements”;and to serve the co-construction,co-management,and sharing of indoor and outdoor public space in urban and rural areas with“public participation.”展开更多
TiNi and Ti-based shape memory alloys were processed by equal channel angular pressing (ECAP) at 673-773 K along Bc route to obtain ultrafine grains for increasing the strength of parent phase and improving the func...TiNi and Ti-based shape memory alloys were processed by equal channel angular pressing (ECAP) at 673-773 K along Bc route to obtain ultrafine grains for increasing the strength of parent phase and improving the functional properties. The effects of both thermodynamically stable and metastable second phases on the mechanical properties and martensitic transformations of these alloys were investigated. It is found that thermodynamically stable Ti2Ni phase has no effect on martensitic transformation and superelasticity of Ti-rich TiNi alloy, thermodynamically stable α phase is harmful for ductility of Ti-Mo-Nb-V-Al alloy, but metastable Ti3Ni4 phase is effective for R phase transformation, martensitic transformation and superelasticity of Ni-rich TiNi alloy. The mechanisms of the second phases on the martensitic transformations and mechanical properties were discussed.展开更多
Aim To study the chromatographis beheviors of three new cinnamyl cyclodextrin derivative stationary phases. Mehtods Three new cinnamyl β-cyclodextrins, heptakis-(2, 6-di-O-cinnamyl-3-O-methyl)-β-CD, heptakis-(2, 6-...Aim To study the chromatographis beheviors of three new cinnamyl cyclodextrin derivative stationary phases. Mehtods Three new cinnamyl β-cyclodextrins, heptakis-(2, 6-di-O-cinnamyl-3-O-methyl)-β-CD, heptakis-(2, 6-di-O-cinnamyl-3-O-acetyl-)-β-CD and heptakis-2, 6-di-O-cirinamyl-3-O-trifluoroacetyl)-β-CD were synthesized and coatal on fused-silica capillary columns . Results The new stationary phases have better thermal stability, good column efficiency and excellent mpaxation power for some sutstituted benzene positional isomers. It was found that the introduction of cinnamyl groups has a significant effect on these stationary phases. Conclusion There new subetituted β-CD compounds are very suitable to be ed as gas chromatographic stationary phases.展开更多
Electron-phonon coupling (EPC) in the three high-pressure phases of Ba is investigated using a pseudopotentlal planewave method based on density functional perturbation theory. The calculated values of superconducti...Electron-phonon coupling (EPC) in the three high-pressure phases of Ba is investigated using a pseudopotentlal planewave method based on density functional perturbation theory. The calculated values of superconducting critical temperature Tc of Ba-I and Ba-II under pressure are consistent well with the trends observed experimentally. Moreover, Ba-V is found to be superconducting with a maximum Tc exceeding 7.8 K at 45 GPa. With the increase of pressure, the values of Tc increase in Ba I and Ba-Ⅱ but the value of Tc decreases in Ba-V. For Ba-I at pressures below 2 GPa, the increases of logarithmic average frequency Oog and electron-phonon coupling parameters , both contribute to the enhancement of Tc. For all the three phases at pressures above 2 GPa, Tc is found to be primarily determined by Further investigation reveals that for all the three phases, the change in with pressure can be explained mainly by change in the phonon frequency. Thus for Ba-II and Ba-V, although they exhibit completely different superconducting behaviors, their superconductivities have the same origin; the pressure dependence of Tc is determined finally by the pressure dependence of phonon frequency.展开更多
Material removal is one of the most used processes in manufacturing. Five-axis CNC machines are believed to be the best tools in sculptured surface machining. In this study, a generic and unified kinematic model was d...Material removal is one of the most used processes in manufacturing. Five-axis CNC machines are believed to be the best tools in sculptured surface machining. In this study, a generic and unified kinematic model was developed as a viable alternative to the particular solutions that are only applicable to individual machine configurations. This versatile model is then used to verify the feasibility of the two rotational joints within the kinematic chain of three main types of a five-axis machine-tool. This versatile model is very useful applied to the design of five-axis machine tools.展开更多
The discrete time wavelet transform has been used to develop software that detects seismic P and S-phases. The detection algorithm is based on the enhanced amplitude and polarization information provided by the wavele...The discrete time wavelet transform has been used to develop software that detects seismic P and S-phases. The detection algorithm is based on the enhanced amplitude and polarization information provided by the wavelet transform coefficients of the raw seismic data. The algorithm detects phases, determines arrival times and indicates the seismic event direction from three component seismic data that represents the ground displacement in three orthogonal directions. The essential concept is that strong features of the seismic signal are present in the wavelet coefficients across several scales of time and direction. The P-phase is detected by generating a function using polarization information while S-phase is detected by generating a function based on the transverse to radial amplitude ratio. These functions are shown to be very effective metrics in detecting P and S-phases and for determining their arrival times for low signal-to-noise arrivals. Results are compared with arrival times obtained by a human analyst as well as with a standard STA/LTA algorithm from local and regional earthquakes and found to be consistent.展开更多
In this paper, the two different Darboux transformations for a Blaszak-Marciniak (BM) three-field lattice equation are constructed. As the applications of the obtained Darboux transformations, new explicit solutions...In this paper, the two different Darboux transformations for a Blaszak-Marciniak (BM) three-field lattice equation are constructed. As the applications of the obtained Darboux transformations, new explicit solutions for the BM lattice are given. We also discuss some properties for these new explicR solutions. Our analysis shows that the explicit solutions possess new characters.展开更多
The asymmetric dual-three phase BLDC motor has two sets of stator windings,in which the back EMF coefficients are different.This paper takes advantage of the asymmetric dual-three phase BLDC motor’s structural featur...The asymmetric dual-three phase BLDC motor has two sets of stator windings,in which the back EMF coefficients are different.This paper takes advantage of the asymmetric dual-three phase BLDC motor’s structural features and proposes a new method for the accelerated problem of the BLDC motor operating in the high speed and the constant electromagnetic power.The dual phase windings of the BLDC motor are integrated into the circuit in the starting stage.When the motor’s back EMF value is equal to the terminal voltage value,switch off a set of RST three phase windingswhose back EMF coefficient is bigger and make the other set of stator windingUVWwith smaller back EMF coefficient continue to operate under the rated power.As the motor rotor speed continues to increase,the electromagnetic torque remains unchanged.By using the peak current control strategy,we can deduce that the phase current of the UVW three-phase winding is twice the RSTthree-phase windingwhen the asymmetric dual-three phase BLDC motor operates at high speed and constant power.展开更多
Film plays an indispensable part in cultural exchange. However, current scholars' studies on the film subtitle translation are less than literary translation. There exists no systematic strategy and theory guiding...Film plays an indispensable part in cultural exchange. However, current scholars' studies on the film subtitle translation are less than literary translation. There exists no systematic strategy and theory guiding it, and there still exists some problems.This paper introduces eco-translatology to film subtitle translation. Eco-translatology proposes that translation is an alternative cycle of translators' adaptation and selection activities in translational eco-environment. The translation method focuses on threedimensional transformation, namely linguistic, cultural and communicative dimensions.展开更多
In this paper,we review the development of a phase theory for systems and networks in its first five years,represented by a trilogy:Matrix phases and their properties;The MIMO LTI system phase response,its physical in...In this paper,we review the development of a phase theory for systems and networks in its first five years,represented by a trilogy:Matrix phases and their properties;The MIMO LTI system phase response,its physical interpretations,the small phase theorem,and the sectored real lemma;The synchronization of a multi-agent network using phase alignment.Towards the end,we also summarize a list of ongoing research on the phase theory and speculate what will happen in the next five years.展开更多
Dual-phase and three-phase grating x-ray interference is a promising new technique for grating-based x-ray differential phase contrast imaging.Dual-phase grating interferometers have been relatively completely studied...Dual-phase and three-phase grating x-ray interference is a promising new technique for grating-based x-ray differential phase contrast imaging.Dual-phase grating interferometers have been relatively completely studied and discussed.In this paper,the corresponding imaging fringe formula of the three-phase grating interferometer is provided.At the same time,the similarities and differences between the three-phase grating interferometer and the dual-phase grating interferometer are investigated and verified,and that the three-phase grating interferometer can produce large-period moiréfringes without using the analyzing grating is demonstrated experimentally.Finally,a simple method of designing three-phase grating and multi-grating imaging systems from geometric optics based on the thin-lens theory of gratings is presented.These theoretical formulas and experimental results provide optimization tools for designing three-phase grating interferometer systems.展开更多
In this paper, performance of three classifiers for classification of five mental tasks were investigated. Wavelet Packet Transform (WPT) was used for feature extraction of the relevant frequency bands from raw Electr...In this paper, performance of three classifiers for classification of five mental tasks were investigated. Wavelet Packet Transform (WPT) was used for feature extraction of the relevant frequency bands from raw Electroencephalograph (EEG) signal. The three classifiers namely used were Multilayer Back propagation Neural Network, Support Vector Machine and Radial Basis Function Neural Network. In MLP-BP NN five training methods used were a) Gradient Descent Back Propagation b) Levenberg-Marquardt c) Resilient Back Propagation d) Conjugate Learning Gradient Back Propagation and e) Gradient Descent Back Propagation with movementum.展开更多
The electrochemical corrosion mechanisms of Mg alloys were extensively studied in previous investigations of different chemical com-positions,modified surface states and various electrolyte conditions.However,recent r...The electrochemical corrosion mechanisms of Mg alloys were extensively studied in previous investigations of different chemical com-positions,modified surface states and various electrolyte conditions.However,recent research focused on the active state of Mg dissolution,leading to unresolved effects of secondary phases adjacent to a stableα-solid solution passive layer.The present study investigates the fundamental electrochemical corrosion mechanisms of three different Laves phases with varying phase morphologies and phase fractions in the passive state of Mg-Al-Ca alloys.The microstructure was characterized by(transmission-)electron microscopy and synchrotron-based transmission X-ray microscopy.The electrochemical corrosion resistance was determined with a standard three-electrode setup and advanced in-situ flow cell measurements.A new electrochemical activity sequence(C15>C36>α-Mg>C14)was obtained,as a result of a stable passive layer formation on theα-solid solution.Furthermore,nm-scale Mg-rich precipitates were identified within the Laves phases,which tend to inhibit the corrosion kinetics.展开更多
Recently,the discovery of superconductivity with a critical temperature Tc up to 80 K in Ruddlesden-Popper phases La_(n+1)Ni_(n)O_(3 n+1)(n=2)under pressure has garnered considerable attention.Up to now,the supercondu...Recently,the discovery of superconductivity with a critical temperature Tc up to 80 K in Ruddlesden-Popper phases La_(n+1)Ni_(n)O_(3 n+1)(n=2)under pressure has garnered considerable attention.Up to now,the superconductivity was only observed in La_(3)Ni_(2)O_(7)single crystal grown with the optical-image float-ing zone furnace under oxygen pressure.It remains to be understood the effect of chemical doping on superconducting La_(3)Ni_(2)O_(7)as well as other Ruddlesden-Popper phases.Here,we systematically investi-gate the effect of external pressure and chemical doping on polycrystalline Ruddlesden-Popper phases.Our results demonstrate that the application of pressure and doping effectively tunes the transport prop-erties of Ruddlesden-Popper phases.We find pressure-induced superconductivity up to 86 K in La_(3)Ni_(2)O_(7)polycrystalline sample,while no signatures of superconductivity are observed in La_(2)NiO_(4)and La_(4)Ni_(3)O_(10)polycrystalline samples under high pressure up to 50 GPa.Our study sheds light on the exploration of high-Tc superconductivity in nickelates.展开更多
Thermal illusion aims to create fake thermal signals or hide the thermal target from the background thermal field to mislead infrared observers,and illusion thermotics was proposed to regulate heat flux with artificia...Thermal illusion aims to create fake thermal signals or hide the thermal target from the background thermal field to mislead infrared observers,and illusion thermotics was proposed to regulate heat flux with artificially structured metamaterials for thermal illusion.Most theoretical and experimental works on illusion thermotics focus on two-dimensional materials,while heat transfer in real three-dimensional(3D)objects remains elusive,so the general 3D illusion thermotics is urgently demanded.In this study,we propose a general method to design 3D thermal illusion metamaterials with varying illusions at different sizes and positions.To validate the generality of the 3D method for thermal illusion metamaterials,we realize thermal functionalities of thermal shifting,splitting,trapping,amplifying and compressing.In addition,we propose a special way to simplify the design method under the condition that the size of illusion target is equal to the size of original heat source.The 3D thermal illusion metamaterial paves a general way for illusion thermotics and triggers the exploration of illusion metamaterials for more functionalities and applications.展开更多
The pasta phases are expected to appear in hot supernova matter and cold neutron stars.In supernova matter,the pasta phases with a series of geometric shapes are studied using the compressible liquid-drop(CLD)model,wh...The pasta phases are expected to appear in hot supernova matter and cold neutron stars.In supernova matter,the pasta phases with a series of geometric shapes are studied using the compressible liquid-drop(CLD)model,where nuclear matter separates into a dense liquid phase of nucleons and a dilute gas phase of nucleons and particles.The equilibrium conditions for two coexisting phases are derived by minimization of the total free energy including the surface and Coulomb contributions.Compared to the results considering only spherical nuclei,the inclusion of pasta phases can delay the transition to uniform matter and enlarge the region of nonuniform matter in the phase diagram.It is found that the density ranges of various pasta shapes depend on both the temperature and the proton fraction.The thermodynamic quantities obtained with the pasta phases using the CLD model are consistent with those in the realistic equation of state table for astrophysical simulations using the Thomas-Fermi approximation.The hadron-quark pasta phases occurring in the interior of massive neutron stars are studied using the energy minimization(EM)method,which is analogous to the CLD method for nuclear pasta.It was found that the hadronquark pasta phases could be significantly affected by the model parameters used.展开更多
In addition to the three well-known Ag-related precipitates(Ω,X′and Z)in the Al-Cu-Mg-Ag alloys,Ag can also be involved in the formation of the as-cast second phases.However,the effect of Ag ad-dition in Al-Cu-Mg-Ag...In addition to the three well-known Ag-related precipitates(Ω,X′and Z)in the Al-Cu-Mg-Ag alloys,Ag can also be involved in the formation of the as-cast second phases.However,the effect of Ag ad-dition in Al-Cu-Mg-Ag alloys has not been completely studied and even the structure of the as-cast Ag-containing phases is still controversial.By employing the focused ion beam(FIB)combined with transmis-sion electron microscopy(TEM)techniques and density functional theory(DFT)calculations,the forma-tion mechanisms of the Ag-containing phases in the as-cast Al-Cu-Mg-Ag alloys have been investigated.The Ag-containing phases are a series of hexagonal C14-type Laves phases with continuously varying Ag concentrations,described as(Al_(x)Cuy Ag_(1-x-y))_(2)Mg.Moreover,the specific occupancy sites of the atoms in(Al_(x)Cuy Ag_(1-x-y))_(2)Mg were determined.The formation of the(Al_(x)Cuy Ag_(1-x-y))_(2)Mg can be attributed to the stronger Ag-induced aggregation of solute atoms in the initial stage and the establishment of strong Ag-X(X=Al,Mg and Ag)bonding in the Ag-containing phases.Furthermore,our experiments have revealed the solidification sequence of Al-Cu-Mg-Ag alloys,and pointed out that(Al_(x)Cuy Ag_(1-x-y))_(2)Mg is formed at a lower temperature(493.9°C)through the reaction L■Al_(2)CuMg+(Al_(x)Cuy Ag_(1-x-y))_(2)Mg.The study could have positive implications for refinement of the Al-Cu-Mg-Ag quaternary phase diagram and promote the composition-property design of novel aluminum alloys based on(Al_(x)Cuy Ag_(1-x-y))_(2)Mg in the future.展开更多
To explore the occurrence phases and enrichment mechanism of rare earth elements(REEs)in cobalt-rich crusts,this study analyzes the mineral composition and REE contents of the samples from Marcus-Wake Seamounts by XRD...To explore the occurrence phases and enrichment mechanism of rare earth elements(REEs)in cobalt-rich crusts,this study analyzes the mineral composition and REE contents of the samples from Marcus-Wake Seamounts by XRD,ICP-OES and ICP-MS.The results show that,(1)the cobalt-rich crusts contain the major crystalline mineral(vernadite),the secondary minerals(quartz,plagioclase and carbonate fluorapatite),and a large amount of amorphous ferric oxyhydroxides(FeOOH).(2)The cobalt-rich crusts contains higher Mn(10.83%to 28.76%)and Fe(6.14%to 18.86%)relative to other elements,and are enriched in REEs,with total REE contents of 1563−3238μg/g and Ce contents of 790−1722μg/g.Rare earth element contents of the old crusts are higher than those of the new crusts.Moreover,the non-phosphatized crusts have positive Ce and negative Y anomalies,and yet the phosphatized crusts have positive Ce and positive Y anomalies,indicating that cobalt-rich crusts is hydrogenetic and REEs mainly come from seawater.(3)Analytical data also show that the occurrence phases of elements in cobalt-rich crusts are closely related to their mineral phases.In the non-phosphatized crusts,REEs are adsorbed by colloidal particles into the crusts(about 67%of REEs in the Fe oxide phase,and about 17%of REEs in the Mn oxide phase).In contrast,in the phosphatized crusts(affected by the phosphatization),REEs may combine with phosphate to form rare earth phosphate minerals,and about 64%of REEs are enriched in the residual phase containing carbonate fluorapatite,but correspondingly the influence of Fe and Mn oxide phases on REEs enrichment is greatly reduced.In addition,the oxidizing environment of seawater,high marine productivity,phosphatization,and slow growth rate can promote the REE enrichment.This study provides a reference for the metallogenesis of cobalt-rich crusts in the Pacific.展开更多
We investigate the topological properties of a two-chain quantum ladder with uneven legs,i.e.,the two chains differ in their periods by a factor of 2.Such an uneven ladder presents rich band structures classified by t...We investigate the topological properties of a two-chain quantum ladder with uneven legs,i.e.,the two chains differ in their periods by a factor of 2.Such an uneven ladder presents rich band structures classified by the closure of either direct or indirect bandgaps.It also provides opportunities to explore fundamental concepts concerning band topology and edge modes,including the difference of intracellular and intercellular Zak phases,and the role of the inversion symmetry(IS).We calculate the Zak phases of the two kinds and find excellent agreement with the dipole moment and extra charge accumulation.We also find that configurations with IS feature a pair of degenerate two-side edge modes emerging as the closure of the direct bandgap,while configurations without IS feature one-side edge modes emerging as not only the closure of both direct and indirect bandgaps but also within the band continuum.Furthermore,by projecting to the two sublattices,we find that the effective Bloch Hamiltonian corresponds to that of a generalized Su–Schrieffer–Heeger model or the Rice–Mele model whose hopping amplitudes depend on the quasimomentum.In this way,the topological phases can be efficiently extracted through winding numbers.We propose that uneven ladders can be realized by spin-dependent optical lattices and their rich topological characteristics can be examined by near future experiments.展开更多
基金Chongqing 2023 Undergraduate Colleges and Universities“Course Ideology and Politics Demonstration Course”and First-Class Undergraduate Course“Offline Course”“Environmental Space Design,”Chongqing College of Engineering 2022 Undergraduate“Course Civics and Politics Demonstration Course”and Gold Course“Offline Course”“Environmental Space Design,”Chongqing 2021 Higher Education Teaching Reform Research Project-Teaching Reform and Practice of Curriculum Civics and Politics Education Integrated into Environmental Design Professional Courses(Key Project)(202127)。
文摘Starting from the characteristics of modernization in three different historical stages since the founding of the People’s Republic of China,this paper analyses the internal changes in the professional name,subordinate disciplines and categories,and professional mission of the environmental design profession,and summarizes the changes in the characteristics of the environmental design profession in 10 aspects such as subordinate disciplines,design objects,design types,cultural characteristics,and aesthetic values on the basis of the results of the analysis,and explores five transformations of the environmental design profession in the process of China’s development in the future.The five transformations in the future development of China are to serve the harmony and beauty of the three major urban and rural spaces with“small and micro-renewal and reconstruction”;to serve the transmission of Chinese culture and the spread of Chinese civilization with“spatial heritage and innovation”;to serve the balance and sufficiency of the four functions of urban and rural settlements with“friendliness and equilibrium”;to serve the intelligence,wisdom,and enjoyment of indoor and outdoor living environment space with“scientific and technological achievements”;and to serve the co-construction,co-management,and sharing of indoor and outdoor public space in urban and rural areas with“public participation.”
基金Project (50671067) supported by the National Natural Science Foundation of ChinaProject (09JC1407200) supported by the Science and Technology Committee of Shanghai, China
文摘TiNi and Ti-based shape memory alloys were processed by equal channel angular pressing (ECAP) at 673-773 K along Bc route to obtain ultrafine grains for increasing the strength of parent phase and improving the functional properties. The effects of both thermodynamically stable and metastable second phases on the mechanical properties and martensitic transformations of these alloys were investigated. It is found that thermodynamically stable Ti2Ni phase has no effect on martensitic transformation and superelasticity of Ti-rich TiNi alloy, thermodynamically stable α phase is harmful for ductility of Ti-Mo-Nb-V-Al alloy, but metastable Ti3Ni4 phase is effective for R phase transformation, martensitic transformation and superelasticity of Ni-rich TiNi alloy. The mechanisms of the second phases on the martensitic transformations and mechanical properties were discussed.
文摘Aim To study the chromatographis beheviors of three new cinnamyl cyclodextrin derivative stationary phases. Mehtods Three new cinnamyl β-cyclodextrins, heptakis-(2, 6-di-O-cinnamyl-3-O-methyl)-β-CD, heptakis-(2, 6-di-O-cinnamyl-3-O-acetyl-)-β-CD and heptakis-2, 6-di-O-cirinamyl-3-O-trifluoroacetyl)-β-CD were synthesized and coatal on fused-silica capillary columns . Results The new stationary phases have better thermal stability, good column efficiency and excellent mpaxation power for some sutstituted benzene positional isomers. It was found that the introduction of cinnamyl groups has a significant effect on these stationary phases. Conclusion There new subetituted β-CD compounds are very suitable to be ed as gas chromatographic stationary phases.
基金supported by the National Natural Science Foundation of China(Grant Nos.11247222,11164020,and 51001042)the Nanyang Normal University Science Foundation,China(Grant Nos.ZX2012018,ZX2010011,and nytc2006k102)+4 种基金the Natural Science Foundation of Science and Technology Departmentof Henan Province,China(Grant Nos.112102210019 and 112300410121)the Natural Science Foundation of Education Department of Henan Province,China(Grant Nos.2011B140015 and 2010B140012)the Higher Education Reform of Henan Province,China(Grant Nos.2012SJGLX233)the China Postdoctoral Science Foundation(Grant No.20110491317)the Young Core Instructor Foundation from the Education Department of Henan Province,China(GrantNo.2012GGJS-152)
文摘Electron-phonon coupling (EPC) in the three high-pressure phases of Ba is investigated using a pseudopotentlal planewave method based on density functional perturbation theory. The calculated values of superconducting critical temperature Tc of Ba-I and Ba-II under pressure are consistent well with the trends observed experimentally. Moreover, Ba-V is found to be superconducting with a maximum Tc exceeding 7.8 K at 45 GPa. With the increase of pressure, the values of Tc increase in Ba I and Ba-Ⅱ but the value of Tc decreases in Ba-V. For Ba-I at pressures below 2 GPa, the increases of logarithmic average frequency Oog and electron-phonon coupling parameters , both contribute to the enhancement of Tc. For all the three phases at pressures above 2 GPa, Tc is found to be primarily determined by Further investigation reveals that for all the three phases, the change in with pressure can be explained mainly by change in the phonon frequency. Thus for Ba-II and Ba-V, although they exhibit completely different superconducting behaviors, their superconductivities have the same origin; the pressure dependence of Tc is determined finally by the pressure dependence of phonon frequency.
文摘Material removal is one of the most used processes in manufacturing. Five-axis CNC machines are believed to be the best tools in sculptured surface machining. In this study, a generic and unified kinematic model was developed as a viable alternative to the particular solutions that are only applicable to individual machine configurations. This versatile model is then used to verify the feasibility of the two rotational joints within the kinematic chain of three main types of a five-axis machine-tool. This versatile model is very useful applied to the design of five-axis machine tools.
文摘The discrete time wavelet transform has been used to develop software that detects seismic P and S-phases. The detection algorithm is based on the enhanced amplitude and polarization information provided by the wavelet transform coefficients of the raw seismic data. The algorithm detects phases, determines arrival times and indicates the seismic event direction from three component seismic data that represents the ground displacement in three orthogonal directions. The essential concept is that strong features of the seismic signal are present in the wavelet coefficients across several scales of time and direction. The P-phase is detected by generating a function using polarization information while S-phase is detected by generating a function based on the transverse to radial amplitude ratio. These functions are shown to be very effective metrics in detecting P and S-phases and for determining their arrival times for low signal-to-noise arrivals. Results are compared with arrival times obtained by a human analyst as well as with a standard STA/LTA algorithm from local and regional earthquakes and found to be consistent.
基金Supported by the National Natural Science Foundation of China under Grant No. 10971136the Ministry of Education and Science of Spain under Grant No. MTM2009-12670
文摘In this paper, the two different Darboux transformations for a Blaszak-Marciniak (BM) three-field lattice equation are constructed. As the applications of the obtained Darboux transformations, new explicit solutions for the BM lattice are given. We also discuss some properties for these new explicR solutions. Our analysis shows that the explicit solutions possess new characters.
基金This work was supported in part by the National Natural Science Foundation of China under Grant 61773006。
文摘The asymmetric dual-three phase BLDC motor has two sets of stator windings,in which the back EMF coefficients are different.This paper takes advantage of the asymmetric dual-three phase BLDC motor’s structural features and proposes a new method for the accelerated problem of the BLDC motor operating in the high speed and the constant electromagnetic power.The dual phase windings of the BLDC motor are integrated into the circuit in the starting stage.When the motor’s back EMF value is equal to the terminal voltage value,switch off a set of RST three phase windingswhose back EMF coefficient is bigger and make the other set of stator windingUVWwith smaller back EMF coefficient continue to operate under the rated power.As the motor rotor speed continues to increase,the electromagnetic torque remains unchanged.By using the peak current control strategy,we can deduce that the phase current of the UVW three-phase winding is twice the RSTthree-phase windingwhen the asymmetric dual-three phase BLDC motor operates at high speed and constant power.
文摘Film plays an indispensable part in cultural exchange. However, current scholars' studies on the film subtitle translation are less than literary translation. There exists no systematic strategy and theory guiding it, and there still exists some problems.This paper introduces eco-translatology to film subtitle translation. Eco-translatology proposes that translation is an alternative cycle of translators' adaptation and selection activities in translational eco-environment. The translation method focuses on threedimensional transformation, namely linguistic, cultural and communicative dimensions.
基金supported in part by the National Natural Science Foundation of China(62073003,72131001)Hong Hong Research Grants Council under GRF grants(16200619,16201120,16205421,1620-3922)Shenzhen-Hong Kong-Macao Science and Technology Innovation Fund(SGDX20201103094600006)。
文摘In this paper,we review the development of a phase theory for systems and networks in its first five years,represented by a trilogy:Matrix phases and their properties;The MIMO LTI system phase response,its physical interpretations,the small phase theorem,and the sectored real lemma;The synchronization of a multi-agent network using phase alignment.Towards the end,we also summarize a list of ongoing research on the phase theory and speculate what will happen in the next five years.
基金Project supported by LingChuang Research Project of China National Nuclear Corporationthe National Natural Science Foundation of China(Grant No.12027812)。
文摘Dual-phase and three-phase grating x-ray interference is a promising new technique for grating-based x-ray differential phase contrast imaging.Dual-phase grating interferometers have been relatively completely studied and discussed.In this paper,the corresponding imaging fringe formula of the three-phase grating interferometer is provided.At the same time,the similarities and differences between the three-phase grating interferometer and the dual-phase grating interferometer are investigated and verified,and that the three-phase grating interferometer can produce large-period moiréfringes without using the analyzing grating is demonstrated experimentally.Finally,a simple method of designing three-phase grating and multi-grating imaging systems from geometric optics based on the thin-lens theory of gratings is presented.These theoretical formulas and experimental results provide optimization tools for designing three-phase grating interferometer systems.
文摘In this paper, performance of three classifiers for classification of five mental tasks were investigated. Wavelet Packet Transform (WPT) was used for feature extraction of the relevant frequency bands from raw Electroencephalograph (EEG) signal. The three classifiers namely used were Multilayer Back propagation Neural Network, Support Vector Machine and Radial Basis Function Neural Network. In MLP-BP NN five training methods used were a) Gradient Descent Back Propagation b) Levenberg-Marquardt c) Resilient Back Propagation d) Conjugate Learning Gradient Back Propagation and e) Gradient Descent Back Propagation with movementum.
基金the financial support of the Deutsche Forschungsgemeinschaft(DFG)of the Collaborative Research Center(CRC)1394“Structural and Chemical Atomic Complexity-from defect phase diagrams to material properties”–project ID 409476157the Excellence Strategy of the Federal Government and the L?nder project IDG:(DE-82)EXS-SF-OPSF596。
文摘The electrochemical corrosion mechanisms of Mg alloys were extensively studied in previous investigations of different chemical com-positions,modified surface states and various electrolyte conditions.However,recent research focused on the active state of Mg dissolution,leading to unresolved effects of secondary phases adjacent to a stableα-solid solution passive layer.The present study investigates the fundamental electrochemical corrosion mechanisms of three different Laves phases with varying phase morphologies and phase fractions in the passive state of Mg-Al-Ca alloys.The microstructure was characterized by(transmission-)electron microscopy and synchrotron-based transmission X-ray microscopy.The electrochemical corrosion resistance was determined with a standard three-electrode setup and advanced in-situ flow cell measurements.A new electrochemical activity sequence(C15>C36>α-Mg>C14)was obtained,as a result of a stable passive layer formation on theα-solid solution.Furthermore,nm-scale Mg-rich precipitates were identified within the Laves phases,which tend to inhibit the corrosion kinetics.
基金supported by the National Natural Science Foundation of China(Grant Nos.52272265,U1932217,11974246,12004252)the National Key R&D Program of China(Grant No.2018YFA0704300)+1 种基金the Shanghai Science and Technology Plan(Grant No.21DZ2260400)support from the Analytical Instrumentation Center(#SPST-AIC10112914),SPST,ShanghaiTech University.
文摘Recently,the discovery of superconductivity with a critical temperature Tc up to 80 K in Ruddlesden-Popper phases La_(n+1)Ni_(n)O_(3 n+1)(n=2)under pressure has garnered considerable attention.Up to now,the superconductivity was only observed in La_(3)Ni_(2)O_(7)single crystal grown with the optical-image float-ing zone furnace under oxygen pressure.It remains to be understood the effect of chemical doping on superconducting La_(3)Ni_(2)O_(7)as well as other Ruddlesden-Popper phases.Here,we systematically investi-gate the effect of external pressure and chemical doping on polycrystalline Ruddlesden-Popper phases.Our results demonstrate that the application of pressure and doping effectively tunes the transport prop-erties of Ruddlesden-Popper phases.We find pressure-induced superconductivity up to 86 K in La_(3)Ni_(2)O_(7)polycrystalline sample,while no signatures of superconductivity are observed in La_(2)NiO_(4)and La_(4)Ni_(3)O_(10)polycrystalline samples under high pressure up to 50 GPa.Our study sheds light on the exploration of high-Tc superconductivity in nickelates.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.52211540005 and 52076087)the Natural Science Foundation of Hubei Province of China (Grant No.2023AFA072)+2 种基金the Open Project Program of Wuhan National Laboratory for Optoelectronics (Grant No.2021WNLOKF004)the Wuhan Knowledge Innovation Shuguang Programthe Science and Technology Program of Hubei Province of China (Grant No.2021BLB176)。
文摘Thermal illusion aims to create fake thermal signals or hide the thermal target from the background thermal field to mislead infrared observers,and illusion thermotics was proposed to regulate heat flux with artificially structured metamaterials for thermal illusion.Most theoretical and experimental works on illusion thermotics focus on two-dimensional materials,while heat transfer in real three-dimensional(3D)objects remains elusive,so the general 3D illusion thermotics is urgently demanded.In this study,we propose a general method to design 3D thermal illusion metamaterials with varying illusions at different sizes and positions.To validate the generality of the 3D method for thermal illusion metamaterials,we realize thermal functionalities of thermal shifting,splitting,trapping,amplifying and compressing.In addition,we propose a special way to simplify the design method under the condition that the size of illusion target is equal to the size of original heat source.The 3D thermal illusion metamaterial paves a general way for illusion thermotics and triggers the exploration of illusion metamaterials for more functionalities and applications.
文摘The pasta phases are expected to appear in hot supernova matter and cold neutron stars.In supernova matter,the pasta phases with a series of geometric shapes are studied using the compressible liquid-drop(CLD)model,where nuclear matter separates into a dense liquid phase of nucleons and a dilute gas phase of nucleons and particles.The equilibrium conditions for two coexisting phases are derived by minimization of the total free energy including the surface and Coulomb contributions.Compared to the results considering only spherical nuclei,the inclusion of pasta phases can delay the transition to uniform matter and enlarge the region of nonuniform matter in the phase diagram.It is found that the density ranges of various pasta shapes depend on both the temperature and the proton fraction.The thermodynamic quantities obtained with the pasta phases using the CLD model are consistent with those in the realistic equation of state table for astrophysical simulations using the Thomas-Fermi approximation.The hadron-quark pasta phases occurring in the interior of massive neutron stars are studied using the energy minimization(EM)method,which is analogous to the CLD method for nuclear pasta.It was found that the hadronquark pasta phases could be significantly affected by the model parameters used.
基金supported by the National Key R&D Program of China(Nos.2020YFF0218200,2016YFB0300800 and 2021YFC1910505)the Innovation Fund Project of GRINM and other related projects.
文摘In addition to the three well-known Ag-related precipitates(Ω,X′and Z)in the Al-Cu-Mg-Ag alloys,Ag can also be involved in the formation of the as-cast second phases.However,the effect of Ag ad-dition in Al-Cu-Mg-Ag alloys has not been completely studied and even the structure of the as-cast Ag-containing phases is still controversial.By employing the focused ion beam(FIB)combined with transmis-sion electron microscopy(TEM)techniques and density functional theory(DFT)calculations,the forma-tion mechanisms of the Ag-containing phases in the as-cast Al-Cu-Mg-Ag alloys have been investigated.The Ag-containing phases are a series of hexagonal C14-type Laves phases with continuously varying Ag concentrations,described as(Al_(x)Cuy Ag_(1-x-y))_(2)Mg.Moreover,the specific occupancy sites of the atoms in(Al_(x)Cuy Ag_(1-x-y))_(2)Mg were determined.The formation of the(Al_(x)Cuy Ag_(1-x-y))_(2)Mg can be attributed to the stronger Ag-induced aggregation of solute atoms in the initial stage and the establishment of strong Ag-X(X=Al,Mg and Ag)bonding in the Ag-containing phases.Furthermore,our experiments have revealed the solidification sequence of Al-Cu-Mg-Ag alloys,and pointed out that(Al_(x)Cuy Ag_(1-x-y))_(2)Mg is formed at a lower temperature(493.9°C)through the reaction L■Al_(2)CuMg+(Al_(x)Cuy Ag_(1-x-y))_(2)Mg.The study could have positive implications for refinement of the Al-Cu-Mg-Ag quaternary phase diagram and promote the composition-property design of novel aluminum alloys based on(Al_(x)Cuy Ag_(1-x-y))_(2)Mg in the future.
基金The fund of Laoshan Laboratory under contract Nos LSKJ202203602 and LSKJ202204103the China Ocean Mineral Resource Research and Development Association Research Program under contract No.DY135-C1-1-04the Taishan Scholarship from Shandong Province.
文摘To explore the occurrence phases and enrichment mechanism of rare earth elements(REEs)in cobalt-rich crusts,this study analyzes the mineral composition and REE contents of the samples from Marcus-Wake Seamounts by XRD,ICP-OES and ICP-MS.The results show that,(1)the cobalt-rich crusts contain the major crystalline mineral(vernadite),the secondary minerals(quartz,plagioclase and carbonate fluorapatite),and a large amount of amorphous ferric oxyhydroxides(FeOOH).(2)The cobalt-rich crusts contains higher Mn(10.83%to 28.76%)and Fe(6.14%to 18.86%)relative to other elements,and are enriched in REEs,with total REE contents of 1563−3238μg/g and Ce contents of 790−1722μg/g.Rare earth element contents of the old crusts are higher than those of the new crusts.Moreover,the non-phosphatized crusts have positive Ce and negative Y anomalies,and yet the phosphatized crusts have positive Ce and positive Y anomalies,indicating that cobalt-rich crusts is hydrogenetic and REEs mainly come from seawater.(3)Analytical data also show that the occurrence phases of elements in cobalt-rich crusts are closely related to their mineral phases.In the non-phosphatized crusts,REEs are adsorbed by colloidal particles into the crusts(about 67%of REEs in the Fe oxide phase,and about 17%of REEs in the Mn oxide phase).In contrast,in the phosphatized crusts(affected by the phosphatization),REEs may combine with phosphate to form rare earth phosphate minerals,and about 64%of REEs are enriched in the residual phase containing carbonate fluorapatite,but correspondingly the influence of Fe and Mn oxide phases on REEs enrichment is greatly reduced.In addition,the oxidizing environment of seawater,high marine productivity,phosphatization,and slow growth rate can promote the REE enrichment.This study provides a reference for the metallogenesis of cobalt-rich crusts in the Pacific.
基金supported by the Natural Science Foundation of Zhejiang Province,China (Grant Nos.LR22A040001 and LY21A040004)the National Natural Science Foundation of China (Grant Nos.12074342 and 11835011)。
文摘We investigate the topological properties of a two-chain quantum ladder with uneven legs,i.e.,the two chains differ in their periods by a factor of 2.Such an uneven ladder presents rich band structures classified by the closure of either direct or indirect bandgaps.It also provides opportunities to explore fundamental concepts concerning band topology and edge modes,including the difference of intracellular and intercellular Zak phases,and the role of the inversion symmetry(IS).We calculate the Zak phases of the two kinds and find excellent agreement with the dipole moment and extra charge accumulation.We also find that configurations with IS feature a pair of degenerate two-side edge modes emerging as the closure of the direct bandgap,while configurations without IS feature one-side edge modes emerging as not only the closure of both direct and indirect bandgaps but also within the band continuum.Furthermore,by projecting to the two sublattices,we find that the effective Bloch Hamiltonian corresponds to that of a generalized Su–Schrieffer–Heeger model or the Rice–Mele model whose hopping amplitudes depend on the quasimomentum.In this way,the topological phases can be efficiently extracted through winding numbers.We propose that uneven ladders can be realized by spin-dependent optical lattices and their rich topological characteristics can be examined by near future experiments.