Exploring electrode materials with a high volumetric energy density and high rate capability remains of a great challenge for nanosized-Li_(4)Ti_(5)O_(12)(LTO)batteries.Here,hierarchical porous Ti^(3+)-C-N-Br co-doped...Exploring electrode materials with a high volumetric energy density and high rate capability remains of a great challenge for nanosized-Li_(4)Ti_(5)O_(12)(LTO)batteries.Here,hierarchical porous Ti^(3+)-C-N-Br co-doped LTO(LTOCPB-CC)is synthesized using carboxyl-grafted nanocarbon(CC)and cetylpyridinium bromide(CPB)as combined structure-directing agents.Ti^(4+)-O-CPB/Li^(+)-CC is designed as a new molecular chelate,in which CPB and CC promote the uniform mixing of Li^(+)and Ti^(4+)and control the morphology of TiO_(2) and the final product.The defects(oxygen vacancies and ion dopants)formed during the annealing process increase the electron/hole concentration and reduce the band gap,both of which enhance the n-type electron modification of LTO.As-prepared LTOCPB-CC has a large specific surface area and high tap density,as well as a high electronic conductivity(2.84×10^(-4) S cm^(-1))and ionic conductivity(3.82×10^(-12)cm^(2) s^(-1)),which are responsible for its excellent rate capability(157.7 mA h g^(-1) at 20 C)and stable long-term cycling performance(0.008% fade per cycle after 1000 cycles at 20 C).展开更多
The rising demand for energy storage solutions,especially in the electric vehicle and renewable energy sectors,highlights the importance of accurately predicting battery health to enhance their longevity and reliabili...The rising demand for energy storage solutions,especially in the electric vehicle and renewable energy sectors,highlights the importance of accurately predicting battery health to enhance their longevity and reliability.This article comprehensively examines various methods used to forecast battery health,including physics-based models,empirical models,and equivalent circuit models,among others.It delves into the promise of data-driven prognostics,utilizing both conventional machine learning and cuttingedge deep neural network techniques.The advantages and limitations of hybrid models are thoroughly analyzed,with a focus on the benefits of integrating diverse data sources to improve prognostic precision.Through practical case studies,the article showcases the effectiveness and flexibility of these approaches.It also critically addresses the challenges encountered in applying battery health prognostics in realworld scenarios,such as issues of scalability,complexity,and data anomalies.Despite these challenges,the article underscores the emerging opportunities brought about by recent technological,academic,and research advancements.These include the development of digital twin models for batteries,the use of data-centric AI and standardized benchmarking,the potential integration of blockchain technology for enhanced data security and transparency,and the synergy between edge and cloud computing to boost data analysis and processing.The primary goal of this article is to enrich the understanding of current battery health prognostic techniques and to inspire further research aimed at overcoming existing hurdles and tapping into new opportunities.It concludes with a visionary perspective on future research directions and potential developments in this evolving field,encouraging both researchers and practitioners to explore innovative solutions.展开更多
The reliable prediction of state of charge(SOC)is one of the vital functions of advanced battery management system(BMS),which has great significance towards safe operation of electric vehicles.By far,the empirical mod...The reliable prediction of state of charge(SOC)is one of the vital functions of advanced battery management system(BMS),which has great significance towards safe operation of electric vehicles.By far,the empirical model-based and data-driven-based SOC estimation methods of lithium-ion batteries have been comprehensively discussed and reviewed in various literatures.However,few reviews involving SOC estimation focused on electrochemical mechanism,which gives physical explanations to SOC and becomes most attractive candidate for advanced BMS.For this reason,this paper comprehensively surveys on physics-based SOC algorithms applied in advanced BMS.First,the research progresses of physical SOC estimation methods for lithium-ion batteries are thoroughly discussed and corresponding evaluation criteria are carefully elaborated.Second,future perspectives of the current researches on physics-based battery SOC estimation are presented.The insights stated in this paper are expected to catalyze the development and application of the physics-based advanced BMS algorithms.展开更多
In this paper,we study the multiplicity and concentration of positive solutions for the following fractional Kirchhoff-Choquard equation with magnetic fields:(aε^(2s)+bε^(4 s-3)[u]_(ε)^(2),A/ε)(-Δ)_(A/ε)^(s)u+V(...In this paper,we study the multiplicity and concentration of positive solutions for the following fractional Kirchhoff-Choquard equation with magnetic fields:(aε^(2s)+bε^(4 s-3)[u]_(ε)^(2),A/ε)(-Δ)_(A/ε)^(s)u+V(x)u=ε^(-α)(Iα*F(|u|^(2)))f(|u|^(2))u in R^(3).Hereε>0 is a small parameter,a,b>0 are constants,s E(0,1),(-Δ)As is the fractional magnetic Laplacian,A:R^(3)→R^(3) is a smooth magnetic potential,Iα=Γ(3-α/2)/2απ3/2Γ(α/2)·1/|x|^(α) is the Riesz potential,the potential V is a positive continuous function having a local minimum,and f:R→R is a C^(1) subcritical nonlinearity.Under some proper assumptions regarding V and f,we show the multiplicity and concentration of positive solutions with the topology of the set M:={x∈R^(3):V(x)=inf V}by applying the penalization method and LjusternikSchnirelmann theory for the above equation.展开更多
The author conducts an empirical research on Chinese performance on Hofstede’s five dimensions in this thesis.Hofstede's Values Survey Module 1994(VSM94)survey instrument is adopted by a sample of 200 Chinese emp...The author conducts an empirical research on Chinese performance on Hofstede’s five dimensions in this thesis.Hofstede's Values Survey Module 1994(VSM94)survey instrument is adopted by a sample of 200 Chinese employees of two international companies,Intel and EY to measure personal values.The author compares the personal values of global company employees in China today with Chinese national culture dimensions which were first identified by Hofstede and the results are very different from Hofstede’s conclusions whose data was collected from 1984 to 1996.According to Hofstede,China is a strongly collectivist,"above average"masculine,high power distance,low uncertainty avoidance and long-term orientation country while the findings of this study is that China has changed to strongly individualistic,strongly feminine,low power distance,high uncertainty avoidance and short-term oriented.The result can to some extent reflect the changed Chinese culture and can serve as the guidance in human resource management.展开更多
Shift of parts of speech in translation is one of the important significance of E-C translation.Because of there are great differences between English and Chinese,such as words structure,grammar,phrases,then translato...Shift of parts of speech in translation is one of the important significance of E-C translation.Because of there are great differences between English and Chinese,such as words structure,grammar,phrases,then translators will use shift of parts of speech to make the essays more fluent,accurate and semantic smooth.That means,when translators translate some passages,some words can not be translated completely equality.This thesis will summarize the four most common shift of parts of speech in E-C translation.展开更多
Based on a generalized Langevin equation,we consider a full general relativistic model to describe the vertical oscillations of particles in accretion disks around compact astrophysical objects,and calculate oscillati...Based on a generalized Langevin equation,we consider a full general relativistic model to describe the vertical oscillations of particles in accretion disks around compact astrophysical objects,and calculate oscillating lumi-nosity and power spectral density(PSD)of an accretion disk.The influences of the friction parameter𝜂,spin parameter𝑏α,and mass𝑁of the center compact object on the stochastic resonance(SR)in PSD curves are discussed.The results show that a large spin parameter𝑏α,can enhance the SR phenomenon,but the larger the𝜂ζor M𝑁is,the weaker the SR phenomenon becomes.In addition,our simulated PSD curves of the output luminosity of stochastically oscillating disk have the same profile as the observed PSD of x-ray binaries,and the resonance peak in the PSD curve can interpret the quasi-periodic oscillations at the same time.展开更多
BACKGROUND: Our previous research proved that vagus nerve stimulation(VNS) improved the neurological outcome after cardiopulmonary resuscitation(CPR) by activating α7 nicotinic acetylcholine receptor(α7nAChR) in a r...BACKGROUND: Our previous research proved that vagus nerve stimulation(VNS) improved the neurological outcome after cardiopulmonary resuscitation(CPR) by activating α7 nicotinic acetylcholine receptor(α7nAChR) in a rat model, but the underlying mechanism of VNS in neuroprotection after CPR remains unclear.METHODS: In vivo, we established a mouse model of cardiac arrest(CA)/CPR to observe the survival rate, and the changes in inflammatory factors and brain tissue after VNS treatment. In vitro, we examined the effects of α7nAChR agonist on ischemia/reperfusion(I/R)-induced inflammation in BV2 cells under oxygen-glucose deprivation/reoxygenation(OGD/R) conditions. We observed the changes in cell survival rate, the levels of inflammatory factors, and the expressions of α7nAChR/Janus kinase 2(JAK2) and toll-like receptor 4(TLR4)/nuclear factor-κB(NF-κB).RESULTS: In vivo, VNS preconditioning enhanced functional recovery, improved the survival rate, and reduced hippocampal CA1 cell damage, and the levels of inflammatory mediators after CA/CPR. The application of α7nAChR agonists provided similar effects against cerebral injury after the return of spontaneous circulation(ROSC), while α7nAChR antagonists reversed these neuroprotective impacts. The in vitro results mostly matched the findings in vivo. OGD/R increased the expression of tumor necrosis factor-alpha(TNF-α), TLR4 and NF-κB p65. When nicotine was added to the OGD/R model, the expression of TLR4, NF-κB p65, and TNF-α decreased, while the phosphorylation of JAK2 increased, which was prevented by preconditioning with α7nAChR or JAK2 antagonists.CONCLUSION: The neuroprotective effect of VNS correlated with the activation of α7nAChR. VNS may alleviate cerebral IR injury by inhibiting TLR4/NF-κB and activating the α7nAChR/JAK2 signaling pathway.展开更多
By using a generalized Langevin equation to describe the vertieal oscillations of a general relativistic disk subjected to a memory-damped friction and a stochastic force, we derive the power spectrum density （PSD） ...By using a generalized Langevin equation to describe the vertieal oscillations of a general relativistic disk subjected to a memory-damped friction and a stochastic force, we derive the power spectrum density （PSD） of accretion disk oscillating luminosity by the method of Laplace transform, and discuss the influence of the system parameters on the resonant behavior in PSD curves. The results show that as the damping strength a and memory time τ of the friction increase, the variation of PSD with spectrum frequency f from monotonous decreasing to occurring maximums, and the phenomenon of a general stochastic resonance （SR） with a single peak and multi-peaks can be found in PSD curves. The radial distance parameter n, the mass M, and spin parameter a, of the black hole determine the inherent frequency of vertical oscillations in the disk, and they have significant influences on the SR phenomena in a system of black hole binaries.展开更多
Let B1 С RN be a unit ball centered at the origin. The main purpose of this paper is to discuss the critical dimension phenomenon for radial solutions of the following quasilinear elliptic problem involving critical ...Let B1 С RN be a unit ball centered at the origin. The main purpose of this paper is to discuss the critical dimension phenomenon for radial solutions of the following quasilinear elliptic problem involving critical Sobolev exponent and singular coefficients：{-div（｜△u｜p-2△u）=｜x｜s｜u｜p＊（s）-2u＋λ｜x｜t｜u｜p-2u, x∈B1, u｜σB1 =0, where t, s〉-p, 2≤p〈N, p＊（s）= （N＋s）pN-p andλ is a real parameter. We show particularly that the above problem exists infinitely many radial solutions if the space dimension N 〉p（p-1）t＋p（p2-p＋1） andλ∈（0,λ1,t）, whereλ1,t is the first eigenvalue of-△p with the Dirichlet boundary condition. Meanwhile, the nonexistence of sign-changing radial solutions is proved if the space dimension N ≤ （ps＋p） min{1, p＋t/p＋s}＋p2p-（p-1） min{1, p＋tp＋s} andλ〉0 is small.展开更多
Magnetics,ferroelectrics,and multiferroics have attracted great attentions because they are not only extremely im-portant for investigating fundamental physics,but also have important applications in information techn...Magnetics,ferroelectrics,and multiferroics have attracted great attentions because they are not only extremely im-portant for investigating fundamental physics,but also have important applications in information technology.Here,recent computational studies on magnetism and ferroelectricity are reviewed.We first give a brief introduction to magnets,fer-roelectrics,and multiferroics.Then,theoretical models and corresponding computational methods for investigating these materials are presented.In particular,a new method for computing the linear magnetoelectric coupling tensor without applying an external field in the first principle calculations is proposed for the first time.The functionalities of our home-made Property Analysis and Simulation Package for materials(PASP)and its applications in the field of magnetism and ferroelectricity are discussed.Finally,we summarize this review and give a perspective on possible directions of future computational studies on magnetism and ferroelectricity.展开更多
The introduction of strain In_(x)Ga_(1-x)As channel with high In content increases the confinement of the two-dimensional electron gas(2DEG)and further improves the high-frequency performance of InGaAs/InAlAs/InP HEMT...The introduction of strain In_(x)Ga_(1-x)As channel with high In content increases the confinement of the two-dimensional electron gas(2DEG)and further improves the high-frequency performance of InGaAs/InAlAs/InP HEMTs.The effect of In_(x)Ga_(1-x)As channel with different In contents on electron irradiation tolerance of InP-based HEMT structures in terms of 2DEG mobility and density has been investigated.The experiment results show that,after the same high electron irradiation dose,the 2DEG mobility and density in InP-based HEMT structures with strain In_(x)Ga_(1-x)As(x>0.53)channel decrease more dramatically than that without strain In_(0.53)Ga_(0.47)As channel.Moreover,the degradation of 2DEG mobility and density becomes more severe as the increase of In content and strain in the In_(x)Ga_(1-x)As channel.The research results can provide some suggestions for the design of radiation-resistant InP-based HEMTs.展开更多
Carbon-doped In Ga As Bi films on In P:Fe(100)substrates have been grown by gas source molecular beam epitaxy(GSMBE).The electrical properties and non-alloyed Ti/Pt/Au contact resistance of n-type carbon-doped In Ga A...Carbon-doped In Ga As Bi films on In P:Fe(100)substrates have been grown by gas source molecular beam epitaxy(GSMBE).The electrical properties and non-alloyed Ti/Pt/Au contact resistance of n-type carbon-doped In Ga As Bi films were characterized by Van der Pauw-Hall measurement and transmission line method(TLM)with and without rapid thermal annealing(RTA).It was found that the specific contact resistance decreases gradually with the increase of carrier concentration.The electron concentration exhibits a sharp increase,and the specific contact resistance shows a noticeable reduction after RTA.With RTA,the In Ga As Bi film grown under CBr4 supply pressure of 0.18 Torr exhibited a high electron concentration of 1.6×10^(21) cm^(-3) and achieved an ultra-low specific contact resistance of 1×10^(-8)Ω·cm^(2),revealing that contact resistance depends greatly on the tunneling effect.展开更多
Considering a damped linear oscillator model subjected to a white noise with an inherent angular frequency and a periodic external driving force, we derive the analytic expression of the first moment of output respons...Considering a damped linear oscillator model subjected to a white noise with an inherent angular frequency and a periodic external driving force, we derive the analytic expression of the first moment of output response, and study the stochastic resonance phenomenon in a system. The results show that the output response of this system behaves as a simple harmonic vibration, of which the frequency is the same as the external driving frequency, and the variations of amplitude with the driving frequency and the inherent frequency present a bona fide stochastic resonance.展开更多
In Tian Qin spaceborne gravitational-wave detectors, the stringent requirements on the magnetic cleanliness of the test masses demand the high resolution ground-based characterization measurement of their magnetic pro...In Tian Qin spaceborne gravitational-wave detectors, the stringent requirements on the magnetic cleanliness of the test masses demand the high resolution ground-based characterization measurement of their magnetic properties. Here we present a single frequency modulation method based on a torsion pendulum to measure the remanent magnetic moment mr of 1.1 kg dummy copper test mass, and the measurement result is(6.45 ± 0.04(stat) ± 0.07(syst)) × 10^(-8)A · m^(2). The measurement precision of the mr is about 0.9 n A · m^(2), well below the present measurement requirement of Tian Qin. The method is particularly useful for measuring extremely low magnetic properties of the materials for use in the construction of space-borne gravitational wave detection and other precision scientific apparatus.展开更多
Inanimate subject is a special grammatical structure in English.However,in Chinese,most sentences begin with animate subjects,so there are some problems in determining how to translate the inanimate subjects in Englis...Inanimate subject is a special grammatical structure in English.However,in Chinese,most sentences begin with animate subjects,so there are some problems in determining how to translate the inanimate subjects in English-Chinese translation.Based on different thinking modes between Chinese and western and on functions of English inanimate-subject sentences,it adopts exem?plification to explore three common translation methods of inanimate subjects in E-C translation,and further introduces the appli?cation of them in different literary forms,so as to deepen understanding of English inanimate-subject sentences.展开更多
Background Although 15 mA transcranial alternating current stimulation(tACS)has a therapeutic effect on depression,the activations of brain structures in humans accounting for this tACS configuration remain largely un...Background Although 15 mA transcranial alternating current stimulation(tACS)has a therapeutic effect on depression,the activations of brain structures in humans accounting for this tACS configuration remain largely unknown.Aims To investigate which intracranial brain structures are engaged in the tACS at 77.5 Hz and 15 mA,delivered via the forehead and the mastoid electrodes in the human brain.Methods Actual human head models were built using the magnetic resonance imagings of eight outpatient volunteers with drug-naïve,first-episode major depressive disorder and then used to perform the electric field distributions with SimNIBS software.Results The electric field distributions of the sagittal,coronal and axial planes showed that the bilateral frontal lobes,bilateral temporal lobes,hippocampus,cingulate,hypothalamus,thalamus,amygdala,cerebellum and brainstem were visibly stimulated by the 15 mA tACS procedure.Conclusions Brain-wide activation,including the cortex,subcortical structures,cerebellum and brainstem,is involved in the 15 mA tACS intervention for first-episode major depressive disorder.Our results indicate that the simultaneous involvement of multiple brain regions is a possible mechanism for its effectiveness in reducing depressive symptoms.展开更多
Lead(Pb)^(0) and iodine(I)^(0) point defects generated during perovskite solar cell(PSC)fabrication and photoconversion form deep band energy levels as the carriers’recombination centers.These defects not only deteri...Lead(Pb)^(0) and iodine(I)^(0) point defects generated during perovskite solar cell(PSC)fabrication and photoconversion form deep band energy levels as the carriers’recombination centers.These defects not only deteriorate device efficiency,but also facilitate chemical degradation with ion migration,resulting in restricted device lifetime.Herein,we present a novel type of phosphines as the point defects stabilizer for hybrid perovskite solar cells with enhanced performances.Three phosphines with varied side groups of tributyl,trioctyl and triphenyl are exampled as the dopants in perovskite films.The group dependent redox properties were observed in the perovskite film,dependent on their molecular weights and steric hinderances of phosphines.The partially oxidized tributyl phosphine(TBUP)with additional tributyl phosphine oxides(TBPO)is efficient in reduction of lead(Pb)^(0) and iodine(I)^(0) concentrations during the device fabrication and operation.The device with TBUP-TBPO pair showed enhanced power conversion efficiency(PCE)to 20.48% and maintain 91.7% of their initial PCEs after 500 h at 65℃ thermal annealing.Thus,this work presents an efficient route of utilize the phosphine species to reduce point defects in the perovskite film,which promoting further development of novel phosphorous additives with defects stabilization,interface passivation and encapsulation for low-cost solution processed PSCs.展开更多
Decellularized extracellular matrix(dECM)is widely used in regenerative medicine as a scaffold material due to its unique biological activity and good biocompatility.Hydrogel is a three dimensional network structure p...Decellularized extracellular matrix(dECM)is widely used in regenerative medicine as a scaffold material due to its unique biological activity and good biocompatility.Hydrogel is a three dimensional network structure polymer with high water content and high swelling that can simulate the water environment of human tissues,has good biocompatibility,and can exchange nutrients,oxygen,and waste with cells.At present,hydrogel is the ideal biological material for tissue engineering.In recent years,rapid development of the hydrogel theory and technology and progress in the use of dECM to form hydrogels have attracted considerable attention to dECM hydrogels as an innovative method for tissue engineering and regenerative medicine.展开更多
The existence and multiplicity of positive solutions are studied for a class of quasi- linear elliptic equations involving Sobolev critical exponents with mixed Dirichlet-Neumann boundary conditions by the variational...The existence and multiplicity of positive solutions are studied for a class of quasi- linear elliptic equations involving Sobolev critical exponents with mixed Dirichlet-Neumann boundary conditions by the variational methods and some analytical techniques.展开更多
基金financially supported by the High-level Innovative Talents Training Project of Guizhou Province(QKHPTRC[2016]5658)the Guizhou Province Graduate Research Fund(YJSCXJH[2018]050)the Guizhou Province Graduate Research Fund(YJSCXJH[2018]081)。
文摘Exploring electrode materials with a high volumetric energy density and high rate capability remains of a great challenge for nanosized-Li_(4)Ti_(5)O_(12)(LTO)batteries.Here,hierarchical porous Ti^(3+)-C-N-Br co-doped LTO(LTOCPB-CC)is synthesized using carboxyl-grafted nanocarbon(CC)and cetylpyridinium bromide(CPB)as combined structure-directing agents.Ti^(4+)-O-CPB/Li^(+)-CC is designed as a new molecular chelate,in which CPB and CC promote the uniform mixing of Li^(+)and Ti^(4+)and control the morphology of TiO_(2) and the final product.The defects(oxygen vacancies and ion dopants)formed during the annealing process increase the electron/hole concentration and reduce the band gap,both of which enhance the n-type electron modification of LTO.As-prepared LTOCPB-CC has a large specific surface area and high tap density,as well as a high electronic conductivity(2.84×10^(-4) S cm^(-1))and ionic conductivity(3.82×10^(-12)cm^(2) s^(-1)),which are responsible for its excellent rate capability(157.7 mA h g^(-1) at 20 C)and stable long-term cycling performance(0.008% fade per cycle after 1000 cycles at 20 C).
基金funded by the Independent Innovation Projects of the Hubei Longzhong Laboratory(2022ZZ-24)the Central Government to Guide Local Science and Technology Development fund Projects of Hubei Province(2022BGE267).
文摘The rising demand for energy storage solutions,especially in the electric vehicle and renewable energy sectors,highlights the importance of accurately predicting battery health to enhance their longevity and reliability.This article comprehensively examines various methods used to forecast battery health,including physics-based models,empirical models,and equivalent circuit models,among others.It delves into the promise of data-driven prognostics,utilizing both conventional machine learning and cuttingedge deep neural network techniques.The advantages and limitations of hybrid models are thoroughly analyzed,with a focus on the benefits of integrating diverse data sources to improve prognostic precision.Through practical case studies,the article showcases the effectiveness and flexibility of these approaches.It also critically addresses the challenges encountered in applying battery health prognostics in realworld scenarios,such as issues of scalability,complexity,and data anomalies.Despite these challenges,the article underscores the emerging opportunities brought about by recent technological,academic,and research advancements.These include the development of digital twin models for batteries,the use of data-centric AI and standardized benchmarking,the potential integration of blockchain technology for enhanced data security and transparency,and the synergy between edge and cloud computing to boost data analysis and processing.The primary goal of this article is to enrich the understanding of current battery health prognostic techniques and to inspire further research aimed at overcoming existing hurdles and tapping into new opportunities.It concludes with a visionary perspective on future research directions and potential developments in this evolving field,encouraging both researchers and practitioners to explore innovative solutions.
基金supported by the Open Project of Hubei Key Laboratory of Power System Design and Test for Electrical Vehicle(No.ZDSYS202304)the National Natural Science Foundation of China(No.62303007)the Anhui Provincial Natural Science Foundation(No.2308085ME142)。
文摘The reliable prediction of state of charge(SOC)is one of the vital functions of advanced battery management system(BMS),which has great significance towards safe operation of electric vehicles.By far,the empirical model-based and data-driven-based SOC estimation methods of lithium-ion batteries have been comprehensively discussed and reviewed in various literatures.However,few reviews involving SOC estimation focused on electrochemical mechanism,which gives physical explanations to SOC and becomes most attractive candidate for advanced BMS.For this reason,this paper comprehensively surveys on physics-based SOC algorithms applied in advanced BMS.First,the research progresses of physical SOC estimation methods for lithium-ion batteries are thoroughly discussed and corresponding evaluation criteria are carefully elaborated.Second,future perspectives of the current researches on physics-based battery SOC estimation are presented.The insights stated in this paper are expected to catalyze the development and application of the physics-based advanced BMS algorithms.
基金supported by National Natural Science Foundation of China(12161038)Science and Technology project of Jiangxi provincial Department of Education(GJJ212204)+1 种基金supported by Natural Science Foundation program of Jiangxi Provincial(20202BABL211005)supported by the Guiding Project in Science and Technology Research Plan of the Education Department of Hubei Province(B2019142)。
文摘In this paper,we study the multiplicity and concentration of positive solutions for the following fractional Kirchhoff-Choquard equation with magnetic fields:(aε^(2s)+bε^(4 s-3)[u]_(ε)^(2),A/ε)(-Δ)_(A/ε)^(s)u+V(x)u=ε^(-α)(Iα*F(|u|^(2)))f(|u|^(2))u in R^(3).Hereε>0 is a small parameter,a,b>0 are constants,s E(0,1),(-Δ)As is the fractional magnetic Laplacian,A:R^(3)→R^(3) is a smooth magnetic potential,Iα=Γ(3-α/2)/2απ3/2Γ(α/2)·1/|x|^(α) is the Riesz potential,the potential V is a positive continuous function having a local minimum,and f:R→R is a C^(1) subcritical nonlinearity.Under some proper assumptions regarding V and f,we show the multiplicity and concentration of positive solutions with the topology of the set M:={x∈R^(3):V(x)=inf V}by applying the penalization method and LjusternikSchnirelmann theory for the above equation.
文摘The author conducts an empirical research on Chinese performance on Hofstede’s five dimensions in this thesis.Hofstede's Values Survey Module 1994(VSM94)survey instrument is adopted by a sample of 200 Chinese employees of two international companies,Intel and EY to measure personal values.The author compares the personal values of global company employees in China today with Chinese national culture dimensions which were first identified by Hofstede and the results are very different from Hofstede’s conclusions whose data was collected from 1984 to 1996.According to Hofstede,China is a strongly collectivist,"above average"masculine,high power distance,low uncertainty avoidance and long-term orientation country while the findings of this study is that China has changed to strongly individualistic,strongly feminine,low power distance,high uncertainty avoidance and short-term oriented.The result can to some extent reflect the changed Chinese culture and can serve as the guidance in human resource management.
文摘Shift of parts of speech in translation is one of the important significance of E-C translation.Because of there are great differences between English and Chinese,such as words structure,grammar,phrases,then translators will use shift of parts of speech to make the essays more fluent,accurate and semantic smooth.That means,when translators translate some passages,some words can not be translated completely equality.This thesis will summarize the four most common shift of parts of speech in E-C translation.
基金Supported by the National Natural Science Foundation of China under Grant No 11045004the Research Foundation of Hubei Provincial Department of Education under Grant No D20132603the Fundamental Research Foundation of Hubei University of Arts and Science under Grant No 2010YA017.
文摘Based on a generalized Langevin equation,we consider a full general relativistic model to describe the vertical oscillations of particles in accretion disks around compact astrophysical objects,and calculate oscillating lumi-nosity and power spectral density(PSD)of an accretion disk.The influences of the friction parameter𝜂,spin parameter𝑏α,and mass𝑁of the center compact object on the stochastic resonance(SR)in PSD curves are discussed.The results show that a large spin parameter𝑏α,can enhance the SR phenomenon,but the larger the𝜂ζor M𝑁is,the weaker the SR phenomenon becomes.In addition,our simulated PSD curves of the output luminosity of stochastically oscillating disk have the same profile as the observed PSD of x-ray binaries,and the resonance peak in the PSD curve can interpret the quasi-periodic oscillations at the same time.
基金supported by research grants from the National Natural Science Foundation of China (grant no. 81571866 and grant no. 82072137)。
文摘BACKGROUND: Our previous research proved that vagus nerve stimulation(VNS) improved the neurological outcome after cardiopulmonary resuscitation(CPR) by activating α7 nicotinic acetylcholine receptor(α7nAChR) in a rat model, but the underlying mechanism of VNS in neuroprotection after CPR remains unclear.METHODS: In vivo, we established a mouse model of cardiac arrest(CA)/CPR to observe the survival rate, and the changes in inflammatory factors and brain tissue after VNS treatment. In vitro, we examined the effects of α7nAChR agonist on ischemia/reperfusion(I/R)-induced inflammation in BV2 cells under oxygen-glucose deprivation/reoxygenation(OGD/R) conditions. We observed the changes in cell survival rate, the levels of inflammatory factors, and the expressions of α7nAChR/Janus kinase 2(JAK2) and toll-like receptor 4(TLR4)/nuclear factor-κB(NF-κB).RESULTS: In vivo, VNS preconditioning enhanced functional recovery, improved the survival rate, and reduced hippocampal CA1 cell damage, and the levels of inflammatory mediators after CA/CPR. The application of α7nAChR agonists provided similar effects against cerebral injury after the return of spontaneous circulation(ROSC), while α7nAChR antagonists reversed these neuroprotective impacts. The in vitro results mostly matched the findings in vivo. OGD/R increased the expression of tumor necrosis factor-alpha(TNF-α), TLR4 and NF-κB p65. When nicotine was added to the OGD/R model, the expression of TLR4, NF-κB p65, and TNF-α decreased, while the phosphorylation of JAK2 increased, which was prevented by preconditioning with α7nAChR or JAK2 antagonists.CONCLUSION: The neuroprotective effect of VNS correlated with the activation of α7nAChR. VNS may alleviate cerebral IR injury by inhibiting TLR4/NF-κB and activating the α7nAChR/JAK2 signaling pathway.
基金supported by the National Natural Science Foundation of China(Grant No.11045004)the Key Program of the Scientific Research Foundation of the Education Bureau of Hubei Province,China(Grant No.D20132603)
文摘By using a generalized Langevin equation to describe the vertieal oscillations of a general relativistic disk subjected to a memory-damped friction and a stochastic force, we derive the power spectrum density （PSD） of accretion disk oscillating luminosity by the method of Laplace transform, and discuss the influence of the system parameters on the resonant behavior in PSD curves. The results show that as the damping strength a and memory time τ of the friction increase, the variation of PSD with spectrum frequency f from monotonous decreasing to occurring maximums, and the phenomenon of a general stochastic resonance （SR） with a single peak and multi-peaks can be found in PSD curves. The radial distance parameter n, the mass M, and spin parameter a, of the black hole determine the inherent frequency of vertical oscillations in the disk, and they have significant influences on the SR phenomena in a system of black hole binaries.
基金supported by the National Natural Science Foundation of China(11326139,11326145)Tian Yuan Foundation(KJLD12067)Hubei Provincial Department of Education(Q20122504)
文摘Let B1 С RN be a unit ball centered at the origin. The main purpose of this paper is to discuss the critical dimension phenomenon for radial solutions of the following quasilinear elliptic problem involving critical Sobolev exponent and singular coefficients：{-div（｜△u｜p-2△u）=｜x｜s｜u｜p＊（s）-2u＋λ｜x｜t｜u｜p-2u, x∈B1, u｜σB1 =0, where t, s〉-p, 2≤p〈N, p＊（s）= （N＋s）pN-p andλ is a real parameter. We show particularly that the above problem exists infinitely many radial solutions if the space dimension N 〉p（p-1）t＋p（p2-p＋1） andλ∈（0,λ1,t）, whereλ1,t is the first eigenvalue of-△p with the Dirichlet boundary condition. Meanwhile, the nonexistence of sign-changing radial solutions is proved if the space dimension N ≤ （ps＋p） min{1, p＋t/p＋s}＋p2p-（p-1） min{1, p＋tp＋s} andλ〉0 is small.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11825403,12188101,and 11804138)the Natural Science Foundation of Anhui Province,China(Grant No.1908085MA10)the Opening Foundation of the State Key Laboratory of Surface Physics of Fudan University(Grant No.KF2019_07)。
文摘Magnetics,ferroelectrics,and multiferroics have attracted great attentions because they are not only extremely im-portant for investigating fundamental physics,but also have important applications in information technology.Here,recent computational studies on magnetism and ferroelectricity are reviewed.We first give a brief introduction to magnets,fer-roelectrics,and multiferroics.Then,theoretical models and corresponding computational methods for investigating these materials are presented.In particular,a new method for computing the linear magnetoelectric coupling tensor without applying an external field in the first principle calculations is proposed for the first time.The functionalities of our home-made Property Analysis and Simulation Package for materials(PASP)and its applications in the field of magnetism and ferroelectricity are discussed.Finally,we summarize this review and give a perspective on possible directions of future computational studies on magnetism and ferroelectricity.
基金National Natural Science Foundation of China(11705277)Science and Technology Research Project of Hubei Provincial Department of Education(Q20222607)Graduate Quality Engineering Support Project of Hubei University of Arts and Science(YZ3202405)。
文摘The introduction of strain In_(x)Ga_(1-x)As channel with high In content increases the confinement of the two-dimensional electron gas(2DEG)and further improves the high-frequency performance of InGaAs/InAlAs/InP HEMTs.The effect of In_(x)Ga_(1-x)As channel with different In contents on electron irradiation tolerance of InP-based HEMT structures in terms of 2DEG mobility and density has been investigated.The experiment results show that,after the same high electron irradiation dose,the 2DEG mobility and density in InP-based HEMT structures with strain In_(x)Ga_(1-x)As(x>0.53)channel decrease more dramatically than that without strain In_(0.53)Ga_(0.47)As channel.Moreover,the degradation of 2DEG mobility and density becomes more severe as the increase of In content and strain in the In_(x)Ga_(1-x)As channel.The research results can provide some suggestions for the design of radiation-resistant InP-based HEMTs.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11705277 and 61434006)the Project of Hubei University of Arts and Science(Grant No.XK2019053)。
文摘Carbon-doped In Ga As Bi films on In P:Fe(100)substrates have been grown by gas source molecular beam epitaxy(GSMBE).The electrical properties and non-alloyed Ti/Pt/Au contact resistance of n-type carbon-doped In Ga As Bi films were characterized by Van der Pauw-Hall measurement and transmission line method(TLM)with and without rapid thermal annealing(RTA).It was found that the specific contact resistance decreases gradually with the increase of carrier concentration.The electron concentration exhibits a sharp increase,and the specific contact resistance shows a noticeable reduction after RTA.With RTA,the In Ga As Bi film grown under CBr4 supply pressure of 0.18 Torr exhibited a high electron concentration of 1.6×10^(21) cm^(-3) and achieved an ultra-low specific contact resistance of 1×10^(-8)Ω·cm^(2),revealing that contact resistance depends greatly on the tunneling effect.
基金Project supported by the National Natural Science Foundation of China(Grant No.11045004)the Key Program of the Scientific Research Foundation of the Education Bureau of Hubei Province,Chain(Grant No.D20101506)
文摘Considering a damped linear oscillator model subjected to a white noise with an inherent angular frequency and a periodic external driving force, we derive the analytic expression of the first moment of output response, and study the stochastic resonance phenomenon in a system. The results show that the output response of this system behaves as a simple harmonic vibration, of which the frequency is the same as the external driving frequency, and the variations of amplitude with the driving frequency and the inherent frequency present a bona fide stochastic resonance.
基金supported by the National Key R&D Program of China (Grant No. 2020YFC2200500)the National Natural Science Foundation of China (Grant Nos. 12075325, 12005308, and 11605065)。
文摘In Tian Qin spaceborne gravitational-wave detectors, the stringent requirements on the magnetic cleanliness of the test masses demand the high resolution ground-based characterization measurement of their magnetic properties. Here we present a single frequency modulation method based on a torsion pendulum to measure the remanent magnetic moment mr of 1.1 kg dummy copper test mass, and the measurement result is(6.45 ± 0.04(stat) ± 0.07(syst)) × 10^(-8)A · m^(2). The measurement precision of the mr is about 0.9 n A · m^(2), well below the present measurement requirement of Tian Qin. The method is particularly useful for measuring extremely low magnetic properties of the materials for use in the construction of space-borne gravitational wave detection and other precision scientific apparatus.
文摘Inanimate subject is a special grammatical structure in English.However,in Chinese,most sentences begin with animate subjects,so there are some problems in determining how to translate the inanimate subjects in English-Chinese translation.Based on different thinking modes between Chinese and western and on functions of English inanimate-subject sentences,it adopts exem?plification to explore three common translation methods of inanimate subjects in E-C translation,and further introduces the appli?cation of them in different literary forms,so as to deepen understanding of English inanimate-subject sentences.
基金The study was partly funded by the National Natural Science Foundation of China(82371490)the National Key R&D Program of China(2022YFC2503900,2022YFC2503901)+1 种基金Beijing Hundred,Thousand and Ten Thousand Talents Project(2017-CXYF-09)Beijing Health System Leading Talent Grant(2022-02-10).
文摘Background Although 15 mA transcranial alternating current stimulation(tACS)has a therapeutic effect on depression,the activations of brain structures in humans accounting for this tACS configuration remain largely unknown.Aims To investigate which intracranial brain structures are engaged in the tACS at 77.5 Hz and 15 mA,delivered via the forehead and the mastoid electrodes in the human brain.Methods Actual human head models were built using the magnetic resonance imagings of eight outpatient volunteers with drug-naïve,first-episode major depressive disorder and then used to perform the electric field distributions with SimNIBS software.Results The electric field distributions of the sagittal,coronal and axial planes showed that the bilateral frontal lobes,bilateral temporal lobes,hippocampus,cingulate,hypothalamus,thalamus,amygdala,cerebellum and brainstem were visibly stimulated by the 15 mA tACS procedure.Conclusions Brain-wide activation,including the cortex,subcortical structures,cerebellum and brainstem,is involved in the 15 mA tACS intervention for first-episode major depressive disorder.Our results indicate that the simultaneous involvement of multiple brain regions is a possible mechanism for its effectiveness in reducing depressive symptoms.
基金supported financially by the National Key Research and Development Plan,China(2017YFE0131900)the National Science Foundation of China(NSFC 51672202,21875178)+1 种基金the Technological Innovation Key Project of Hubei Province(2018AAA048)the support the“Chutian Scholar Program”of Hubei Province,China。
文摘Lead(Pb)^(0) and iodine(I)^(0) point defects generated during perovskite solar cell(PSC)fabrication and photoconversion form deep band energy levels as the carriers’recombination centers.These defects not only deteriorate device efficiency,but also facilitate chemical degradation with ion migration,resulting in restricted device lifetime.Herein,we present a novel type of phosphines as the point defects stabilizer for hybrid perovskite solar cells with enhanced performances.Three phosphines with varied side groups of tributyl,trioctyl and triphenyl are exampled as the dopants in perovskite films.The group dependent redox properties were observed in the perovskite film,dependent on their molecular weights and steric hinderances of phosphines.The partially oxidized tributyl phosphine(TBUP)with additional tributyl phosphine oxides(TBPO)is efficient in reduction of lead(Pb)^(0) and iodine(I)^(0) concentrations during the device fabrication and operation.The device with TBUP-TBPO pair showed enhanced power conversion efficiency(PCE)to 20.48% and maintain 91.7% of their initial PCEs after 500 h at 65℃ thermal annealing.Thus,this work presents an efficient route of utilize the phosphine species to reduce point defects in the perovskite film,which promoting further development of novel phosphorous additives with defects stabilization,interface passivation and encapsulation for low-cost solution processed PSCs.
文摘Decellularized extracellular matrix(dECM)is widely used in regenerative medicine as a scaffold material due to its unique biological activity and good biocompatility.Hydrogel is a three dimensional network structure polymer with high water content and high swelling that can simulate the water environment of human tissues,has good biocompatibility,and can exchange nutrients,oxygen,and waste with cells.At present,hydrogel is the ideal biological material for tissue engineering.In recent years,rapid development of the hydrogel theory and technology and progress in the use of dECM to form hydrogels have attracted considerable attention to dECM hydrogels as an innovative method for tissue engineering and regenerative medicine.
基金Supported by National Natural Science Foundation of China (11071198 11101347)+2 种基金Postdoctor Foundation of China (2012M510363)the Key Project in Science and Technology Research Plan of the Education Department of Hubei Province (D20112605 D20122501)
文摘The existence and multiplicity of positive solutions are studied for a class of quasi- linear elliptic equations involving Sobolev critical exponents with mixed Dirichlet-Neumann boundary conditions by the variational methods and some analytical techniques.
