Underwater monopulse space-time adaptive track-before-detect method,which combines space-time adaptive detector(STAD)and the track-before-detect algorithm based on dynamic programming(DP-TBD),denoted as STAD-DP-TBD,ca...Underwater monopulse space-time adaptive track-before-detect method,which combines space-time adaptive detector(STAD)and the track-before-detect algorithm based on dynamic programming(DP-TBD),denoted as STAD-DP-TBD,can effectively detect low-speed weak targets.However,due to the complexity and variability of the underwater environment,it is difficult to obtain sufficient secondary data,resulting in a serious decline in the detection and tracking performance,and leading to poor robustness of the algorithm.In this paper,based on the adaptive matched filter(AMF)test and the RAO test,underwater monopulse AMF-DP-TBD algorithm and RAO-DP-TBD algorithm which incorporate persymmetry and symmetric spectrum,denoted as PSAMF-DP-TBD and PS-RAO-DP-TBD,are proposed and compared with the AMF-DP-TBD algorithm and RAO-DP-TBD algorithm based on persymmetry array,denoted as P-AMF-DP-TBD and P-RAO-DP-TBD.The simulation results show that the four methods can work normally with sufficient secondary data and slightly insufficient secondary data,but when the secondary data is severely insufficient,the P-AMF-DP-TBD and P-RAO-DP-TBD algorithms has failed while the PSAMF-DP-TBD and PS-RAO-DP-TBD algorithms still have good detection and tracking capabilities.展开更多
In order to improve the rejection capability of mismatched interferer signals,a new two-stage detector is proposed under homogeneous scenarios with unknown covariance matrix,which is obtained by cascading the adaptive...In order to improve the rejection capability of mismatched interferer signals,a new two-stage detector is proposed under homogeneous scenarios with unknown covariance matrix,which is obtained by cascading the adaptive matched filter(AMF)detector and the enhanced RAO(EnRAO)detector.The new detector has constant false alarm performance,and the closed-form expression of probability of false alarm and probability of detection is derived.The performance of the new detector is assessed,and analyzed in comparison with other detectors.The results show that,the proposed detector can provide enhanced rejection capability in the case of mismatch,but the performance of the detector is slightly lost under the condition of matching.展开更多
Composite polymer electrolytes(CPEs)are considered to be the most promising to break through the performance and safety limitations of traditional lithium-ion batteries because of their excellent electrochemical and m...Composite polymer electrolytes(CPEs)are considered to be the most promising to break through the performance and safety limitations of traditional lithium-ion batteries because of their excellent electrochemical and mechanical properties.Aiming at the performance limitations of the most common polyether matrix such as poly(ethylene oxide)(PEO),a novel poly(cyclocarbonate-ether)polymer matrix was prepared by in-situ thermal curing,the weaker interaction between its C=O bond and Li^(+)can promote the rapid transport of Li^(+).Adding ionic liquid and active filler LLZTO to the matrix can synergistically reduce the crystallinity of matrix and promote the dissociation of lithium salts.In addition,a 3D functional skeleton made of polyacrylonitrile(PAN)and lithium fluoride(LiF)can greatly improve the mechanical strength of polymer matrix after cold pressing,and Li F is also conducive to interface stability.The thickness of the optimal sample(VP6L/CPL)was only 25μm,and its ionic conductivity,lithium ion transference number,and electrochemical stability window were as high as 7.17×10^(-4)S cm^(-1)(25℃),0.54 and 5.4 V,respectively,while the mechanical strength reaches 6.1 MPa,which can fully inhibit the growth of lithium dendrites.The excellent electrochemical performance and mechanical strength enable the assembled Li|VP6L/CPL|Li battery to be continuously charged for over 200 h and cycled stably for more than 2300 h,and Li|VP6L/CPL|LFP battery can be stably cycled for more than 400 and 550 cycles at 1 C(40℃)and 0.5 C(25℃),respectively.展开更多
In this paper, a new kind of alternating direction implicit(ADI) Crank-Nicolsontype orthogonal spline collocation(OSC) method is formulated for the two-dimensional fractional evolution equation with a weakly singular ...In this paper, a new kind of alternating direction implicit(ADI) Crank-Nicolsontype orthogonal spline collocation(OSC) method is formulated for the two-dimensional fractional evolution equation with a weakly singular kernel arising in the theory of linear viscoelasticity. The novel OSC method is used for the spatial discretization, and ADI Crank-Nicolsontype method combined with the second order fractional quadrature rule are considered for the temporal component. The stability of proposed scheme is rigourously established, and nearly optimal order error estimate is also derived. Numerical experiments are conducted to support the predicted convergence rates and also exhibit expected super-convergence phenomena.展开更多
In this paper, we investigate the effect of layer thickness on the residual stresses of copper indium gallium diselenide (CIGS) solar cells with polyimide substrate caused by CIGS layer deposition at 400?C and then co...In this paper, we investigate the effect of layer thickness on the residual stresses of copper indium gallium diselenide (CIGS) solar cells with polyimide substrate caused by CIGS layer deposition at 400?C and then cooling down to room temperature using the Finite Element Method (FEM). Moreover, we also examined the effect of layer thickness on residual stress of CIGS solar cells after cooling down to room temperature from the hotspot temperatures of 200?C, 300?C, and 400?C. Our simulated CIGS is composed of five layers: ZnO, CdS, CIGS, Mo, and PI substrate. We were able to quantify the effect of each layer’s thickness and hotspot temperature on the average stresses of each layer for the CIGS solar cells. We found that the PI substrate layer has the most significant effect on the residual stress of CIGS solar cells. Our simulation results reveal that the stress type (tensile vs. compressive) and the magnitude of stress of the CIGS layer (main absorber layer) can be controlled by changing the thickness of the PI substrate while applying a heat to CIGS solar cells. Quantitative analysis of relationship between layer thickness and thermo-mechanical stress of thin film solar cells can help solar cell manufacturers design more robust and reliable solar cells. For example, fabricating PI layer thickness less than 17 μm can improve the performance of CIGS solar cells by nullifying the compressive residual stress in the CIGS absorber layer.展开更多
Dynamical decoupling is widely used in many quantum computing systems to combat decoherence. In a practical superconducting quantum system, imperfections can plague decoupling performance. In this work, imperfections ...Dynamical decoupling is widely used in many quantum computing systems to combat decoherence. In a practical superconducting quantum system, imperfections can plague decoupling performance. In this work, imperfections in a superconducting qubit and its control system are modeled via modified Hamiltonian and collapse operator. A master equation simulation is carried out on the qubit under 1/f environment noise spectrum. The average dephasing rate of qubit is extracted to characterize the impact of different imperfections on the decoupling from dephasing. We find that the precision of pulse position, on–off ratio, and filtering effect are most critical. Bounded pulses have weaker impact,while variation in pulse width and qubit relaxation are insignificant. Consequently, alternative decoupling protocols, jitter mitigation, cascaded mixers, and pulse shaping can be conducive to the performance of decoupling. This work may assist the analysis and optimization of dynamical decoupling on noisy superconducting quantum systems.展开更多
When there is a certain amount of field inhomogeneity,the biased ferrimagnetic crystal can exhibit the higher-order magnetostatic(HMS)mode in addition to the uniform-precession Kittel mode.In cavity magnonics,we show ...When there is a certain amount of field inhomogeneity,the biased ferrimagnetic crystal can exhibit the higher-order magnetostatic(HMS)mode in addition to the uniform-precession Kittel mode.In cavity magnonics,we show the nonlinearity and heating-induced frequency shifts of the Kittel mode and HMS mode in a yttrium-iron-garnet(YIG)sphere.When the Kittel mode is driven to generate a certain number of excitations,the temperature of the whole YIG sample rises and the HMS mode can display an induced frequency shift,and vice versa.This cross effect provides a new method to study the magnetization dynamics and paves a way for novel cavity magnonic devices by including the heating effect as an operational degree of freedom.展开更多
Enolase 2(ENO2)is a key glycolytic enzyme in the metabolic process of glycolysis,but its potential function in pancreatic ductal adenocarcinoma(PDAC)is unclear.In this study,we observed a significant overexpression of...Enolase 2(ENO2)is a key glycolytic enzyme in the metabolic process of glycolysis,but its potential function in pancreatic ductal adenocarcinoma(PDAC)is unclear.In this study,we observed a significant overexpression of ENO2 in PDAC tissues,and its expression was correlated with metastasis and poor prognosis in PDAC patients.K394 was identified as a major acetylation site in ENO2 that regulates its enzymatic activity,cell metabolism and PDAC progression.Knockdown of ENO2 suppressed tumor growth and liver metastasis in PDAC.Re-expression of wild-type(WT)ENO2,but not the K394 acetylation mimetic mutant,could reverse the decreased tumor malignancy.We further characterized histone deacetylase 3(HDAC3)and P300/CBP-associated factor(PCAF)as the potential deacetylase and acetyltransferase for ENO2,respectively.HDAC3-mediated deacetylation was shown to lead to ENO2 activation and enhancement of glycolysis.Importantly,insulin-like growth factor-1(IGF-1)was found to decrease K394 acetylation and stimulate ENO2 activity in a dose-and time-dependent manner.The PI3K/AKT/mTOR pathway facilitated the phosphorylation of HDAC3 on S424,which promoted K394 deacetylation and activation of ENO2.Linsitinib,an oral small-molecule inhibitor of IGF-1R,could inhibit IGF-1-induced ENO2 deacetylation by HDAC3 and the PI3K/AKT/mTOR pathway.Furthermore,linsitinib showed a different effect on the growth and metastasis of PDAC depending on the overexpression of WT versus K394-mutant ENO2.Our results reveal a novel mechanism by which acetylation negatively regulates ENO2 activity in the metastasis of PDAC by modulating glycolysis.Blockade of IGF-1-induced ENO2 deacetylation represents a promising strategy to prevent the development of PDAC.展开更多
Length-biased data are encountered in many fields,including economics,engineering and epidemiological cohort studies.There are two main challenges in the analysis of such data:the assumption of independent censoring i...Length-biased data are encountered in many fields,including economics,engineering and epidemiological cohort studies.There are two main challenges in the analysis of such data:the assumption of independent censoring is violated and the assumed model for the underlying population is no longer satisfied for the observed data.In this paper,a proportional mean residual life varyingcoefficient model for length-biased data is considered and a local pseudo likelihood method is proposed for estimating the coefficient functions in the model.Asymptotic properties are investigated for the proposed estimators.The finite sample performance of the proposed methodology is demonstrated by simulation studies.Finally,the method is applied to a real data set concerning the Academy Awards.展开更多
Tip-enhanced Raman spectroscopy(TERS)imaging is a super-resolution imaging technique that features the merits of both surface-enhanced Raman spectroscopy(SERS)and scanning probe microscopy(SPM),such as the high chemic...Tip-enhanced Raman spectroscopy(TERS)imaging is a super-resolution imaging technique that features the merits of both surface-enhanced Raman spectroscopy(SERS)and scanning probe microscopy(SPM),such as the high chemical sensitivity from the former and the nanoscale spatial resolution from the latter.These advantages make TERS an essential nanospectroscopic characterization technique for chemical analysis,materials science,bio-sensing,etc.TERS probes,the most critical factor determining the TERS imaging quality,are expected to provide a highly confined electromagnetic hotspot with a minimized scattering background for the generation of Raman signals with high spatial resolution.After two decades of development,numerous probe design concepts have been proposed and demonstrated.This review provides a comprehensive overview of the state-of-the-art TERS probe designs,from the working mechanism to the practical performance.We start with reviewing the recent development of TERS configurations and the corresponding working mechanisms,including the SPM platforms,optical excitation/collection techniques,and probe preparation methods.We then review the emerging novel TERS probe designs,including the remote-excitation probes,the waveguide-based nanofocusing probes,the metal-coated nanofocusing probes,the nanowire-assisted selective-coupling probes,and the tapered metal-insulator-metal probes.Our discussion focuses on a few critical aspects,including the surface-plasmon-polariton(SPP)hotspot excitation technique,conversion efficiency,working frequency,and controllability.In the end,we review the latest TERS applications and give a perspective on the future of TERS.展开更多
Objective:Although the neurological and olfactory symptoms of coronavirus disease 2019 have been identified,the neurotropic properties of the causative virus,severe acute respiratory syndrome-associated coronavirus 2(...Objective:Although the neurological and olfactory symptoms of coronavirus disease 2019 have been identified,the neurotropic properties of the causative virus,severe acute respiratory syndrome-associated coronavirus 2(SARS-CoV-2),remain unknown.We sought to identify the susceptible cell types and potential routes of SARS-CoV-2 entry into the central nervous system,olfactory system,and respiratory system.Methods:We collected single-cell RNA data from normal brain and nasal epithelium specimens,along with bronchial,tracheal,and lung specimens in public datasets.The susceptible cell types that express SARS-CoV-2 entry genes were identified using single-cell RNA sequencing and the expression of the key genes at protein levels was verified by immunohistochemistry.We compared the coexpression patterns of the entry receptor angiotensin-converting enzyme 2(ACE2)and the spike protein priming enzyme transmembrane serine protease(TMPRSS)/cathepsin L among the specimens.Results:The SARS-CoV-2 entry receptor ACE2 and the spike protein priming enzyme TMPRSS/cathepsin L were coexpressed by pericytes in brain tissue;this coexpression was confirmed by immunohistochemistry.In the nasal epithelium,ciliated cells and sustentacular cells exhibited strong coexpression of ACE2 and TMPRSS.Neurons and glia in the brain and nasal epithelium did not exhibit coexpression of ACE2 and TMPRSS.However,coexpression was present in ciliated cells,vascular smooth muscle cells,and fibroblasts in tracheal tissue;ciliated cells and goblet cells in bronchial tissue;and alveolar epithelium type 1 cells,AT2 cells,and ciliated cells in lung tissue.Conclusion:Neurological symptoms in patients with coronavirus disease 2019 could be associated with SARS-CoV-2 invasion across the blood-brain barrier via pericytes.Additionally,SARS-CoV-2-induced olfactory disorders could be the result of localized cell damage in the nasal epithelium.展开更多
Background The efficacy of immune checkpoint inhibitors(ICIs),such as programmed cell death protein-1(PD-1)or its ligand 1(PD-L1)antibody,in hepatocellular carcinoma(HCC)is limited,and it is recommended that they be c...Background The efficacy of immune checkpoint inhibitors(ICIs),such as programmed cell death protein-1(PD-1)or its ligand 1(PD-L1)antibody,in hepatocellular carcinoma(HCC)is limited,and it is recommended that they be combined with other therapies.We evaluated the combination of pegylated interferon-α(Peg-IFNα)with PD-1 blockade in HCC mouse models.Methods We analyzed the effects of Peg-IFNαon tumor-infiltrating immune cells and PD-1 expression in the HCC immune microenvironment and examined the underlying mechanism of its unique effect on the PD-1 pathway.The in vivo efficacy of anti-PD-1 and Peg-IFNαwas evaluated in both subcutaneous and orthotopic mouse models of HCC.Results The combination of Peg-IFNαwith PD-1 blockade dramatically enhanced T-cell infiltration,improved the efficacy of PD-1 antibody and prolonged mouse survival compared with PD-1 antibody monotherapy.Mechanistically,Peg-IFNαcould recruit cytotoxic CD8+T cells to infiltrate the HCC microenvironment by inducing tumor cells to secrete the chemokine CCL4.Nevertheless,the HCC microenvironment quickly overcame the immune responses by upregulating PD-1 expression in CD8+T cells via the IFNα-IFNAR1-JAK1-STAT3 signaling pathway.The combination of PD-1 blockade with Peg-IFNαcould restore the cytotoxic capacity of CD8+T cells and exerted a significant synergistic effect on HCC.Conclusion These results indicate that in addition to initiating the antitumor immune response itself,Peg-IFNαcan also generate a microenvironment favoring PD-1 blockade.Thus,the combination of Peg-IFNαand PD-1 blockade can be a promising strategy for HCC.展开更多
Spontaneous symmetry breaking has revolutionized the understanding in numerous fields of modern physics. Here, we theoretically demonstrate the spontaneous time-reversal symmetry breaking in a cavity quantum electrody...Spontaneous symmetry breaking has revolutionized the understanding in numerous fields of modern physics. Here, we theoretically demonstrate the spontaneous time-reversal symmetry breaking in a cavity quantum electrodynamics system in which an atomic ensemble interacts coherently with a single resonant cavity mode. The interacting system can be effectively described by two coupled oscillators with positive and negative mass, when the two-level atoms are prepared in their excited states. The occurrence of symmetry breaking is controlled by the atomic detuning and the coupling to the cavity mode,which naturally divides the parameter space into the symmetry broken and symmetry unbroken phases.The two phases are separated by a spectral singularity, a so-called exceptional point, where the eigenstates of the Hamiltonian coalesce. When encircling the singularity in the parameter space, the quasiadiabatic dynamics shows chiral mode switching which enables topological manipulation of quantum states.展开更多
Introduction:National Notifiable Disease Reporting System(NNDRS)plays an important role in the early detection and control of tuberculosis(TB)in China.This study analyzed the epidemiological characteristics of pulmona...Introduction:National Notifiable Disease Reporting System(NNDRS)plays an important role in the early detection and control of tuberculosis(TB)in China.This study analyzed the epidemiological characteristics of pulmonary tuberculosis(PTB)in Kashgar Prefecture,Xinjiang Uygur Autnomous Region,China from 2011 to 2020 to provide a scientific basis for developing TB control strategies and measures in Kashgar.Methods:The data were collected from the NNDRS,which included the geographical distribution,age,sex,occupation,and pathogenic classification of reported PTB cases in 12 counties/cities of Kashgar Prefecture from 2011 to 2020.Descriptive statistics were used to describe the characteristic of PTB epidemic in Kashgar.Results:There were 189,416 PTB cases reported during 2011–2020,with a mean annual PTB case notification rate(CNR)of 451.29/100,000.A rising trend in the rate of reported PTB between 2011 and 2017(χ2 trend=26.09,P<0.01)and a declining trend between 2018 and 2020(χ2 trend=314.44,P<0.01)were observed.The months with the highest reported number of PTB cases were March to May and November to December.The mean annual rate of reported PTB was 451.88/100,000 for males and 450.67/100,000 for females.In addition,19.76%of patients were bacteriologically-confirmed(Bac+)cases(37,425/189,416),and the mean annual Bac+CNR was 89.17/100,000,rising from 64.76/100,000 in 2011 to 139.12/100,000 in 2020(χ^(2)_(trend)=74.44,P<0.01).Conclusions:The CNR of reported PTB in Kashgar showed a significant declining trend in the past three years.Males,elderly population,winter and spring,and farmers as an occupation were the main factors associated with high incidence of tuberculosis in Kashgar.Targeted prevention and treatment of TB should be strengthened in key groups in this region.展开更多
This paper is concerned with a compact difference scheme with the truncation error of order 3/2 for time and order 4 for space to an evolution equation with a weakly singular kernel.The integral term is treated by mea...This paper is concerned with a compact difference scheme with the truncation error of order 3/2 for time and order 4 for space to an evolution equation with a weakly singular kernel.The integral term is treated by means of the second order convolution quadrature suggested by Lubich.The stability and convergence are proved by the energy method.A numerical experiment is reported to verify the theoretical predictions.展开更多
Silver nanowires (AgNWs) hold great promise for applications in wearable electronics, flexible solar cells, chemical and biological sensors, photonic/plasmonic circuits, and scanning probe microscopy (SPM) due to thei...Silver nanowires (AgNWs) hold great promise for applications in wearable electronics, flexible solar cells, chemical and biological sensors, photonic/plasmonic circuits, and scanning probe microscopy (SPM) due to their unique plasmonic, mechanical, and electronic properties. However, the lifetime, reliability, and operating conditions of AgNW-based devices are significantly restricted by their poor chemical stability, limiting their commercial potentials. Therefore, it is crucial to create a reliable oxidation barrier on AgNWs that provides long-term chemical stability to various optical, electrical, and mechanical devices while maintaining their high performance. Here we report a room-temperature solution-phase approach to grow an ultra-thin, epitaxial gold coating on AgNWs to effectively shield the Ag surface from environmental oxidation. The Ag@Au core-shell nanowires (Ag@Au NWs) remain stable in air for over six months, under elevated temperature and humidity (80 °C and 100% humidity) for twelve weeks, in physiological buffer solutions for three weeks, and can survive overnight treatment of an oxidative solution (2% H2O2). The Ag@Au core-shell NWs demonstrated comparable performance as pristine AgNWs in various electronic, optical, and mechanical devices, such as transparent mesh electrodes, surface-enhanced Raman spectroscopy (SERS) substrates, plasmonic waveguides, plasmonic nanofocusing probes, and high-aspect-ratio, high-resolution atomic force microscopy (AFM) probes. These Au@Ag core-shell NWs offer a universal solution towards chemically-stable AgNW-based devices without compromising material property or device performance.展开更多
Synchronization is of importance in both fundamental and applied physics,but its demonstration at the micro/nanoscale is mainly limited to low-frequency oscillations such as mechanical resonators.We report the synchro...Synchronization is of importance in both fundamental and applied physics,but its demonstration at the micro/nanoscale is mainly limited to low-frequency oscillations such as mechanical resonators.We report the synchronization of two coupled optical microresonators,in which the high-frequency resonances in the optical domain are aligned with reduced noise.It is found that two types of synchronization regimes emerge with either the first-or second-order transition,both presenting a process of spontaneous symmetry breaking.In the second-order regime,the synchronization happens with an invariant topological character number and a larger detuning than that of the first-order case.Furthermore,an unconventional hysteresis behavior is revealed for a time-dependent coupling strength,breaking the static limitation and the temporal reciprocity.The synchronization of optical microresonators offers great potential in reconfigurable simulations of manybody physics and scalable photonic devices on a chip.展开更多
Since the Chinese economic reform in 1978,its medical field has made remarkable progress in the past 40 years.In most medical fields,China’s diagnosis and treatment methods are comparable to the international high st...Since the Chinese economic reform in 1978,its medical field has made remarkable progress in the past 40 years.In most medical fields,China’s diagnosis and treatment methods are comparable to the international high standards.In recent years,with the continuous expansion of the medical research team and the improvement of laboratory research equipment and methods,China has achieved some influential and internationally recognized research outcomes.However,overall,China still lags behind developed countries in terms of high-level original medical research,especially in high evidence-based medical research(1).展开更多
Quantum entanglement,since proposed by Einstein,Podolsky and Rosen(EPR)[1]and further explored by Schr?dinger[2]in1935,has always been the focus of quantum physics realm.The EPR paradox revealed the conflict between q...Quantum entanglement,since proposed by Einstein,Podolsky and Rosen(EPR)[1]and further explored by Schr?dinger[2]in1935,has always been the focus of quantum physics realm.The EPR paradox revealed the conflict between quantum theory and local realism.Almost 30 years later,in 1964,Bell first came up with the prototype of a family of inequalities,which was later called Bell inequality[3,4],to express certain limitation that every local clas-展开更多
基金supported by the National Natural Science Foundation of China (No.61971412)。
文摘Underwater monopulse space-time adaptive track-before-detect method,which combines space-time adaptive detector(STAD)and the track-before-detect algorithm based on dynamic programming(DP-TBD),denoted as STAD-DP-TBD,can effectively detect low-speed weak targets.However,due to the complexity and variability of the underwater environment,it is difficult to obtain sufficient secondary data,resulting in a serious decline in the detection and tracking performance,and leading to poor robustness of the algorithm.In this paper,based on the adaptive matched filter(AMF)test and the RAO test,underwater monopulse AMF-DP-TBD algorithm and RAO-DP-TBD algorithm which incorporate persymmetry and symmetric spectrum,denoted as PSAMF-DP-TBD and PS-RAO-DP-TBD,are proposed and compared with the AMF-DP-TBD algorithm and RAO-DP-TBD algorithm based on persymmetry array,denoted as P-AMF-DP-TBD and P-RAO-DP-TBD.The simulation results show that the four methods can work normally with sufficient secondary data and slightly insufficient secondary data,but when the secondary data is severely insufficient,the P-AMF-DP-TBD and P-RAO-DP-TBD algorithms has failed while the PSAMF-DP-TBD and PS-RAO-DP-TBD algorithms still have good detection and tracking capabilities.
基金supported by the National Natural Science Foundation of China(No.61971412).
文摘In order to improve the rejection capability of mismatched interferer signals,a new two-stage detector is proposed under homogeneous scenarios with unknown covariance matrix,which is obtained by cascading the adaptive matched filter(AMF)detector and the enhanced RAO(EnRAO)detector.The new detector has constant false alarm performance,and the closed-form expression of probability of false alarm and probability of detection is derived.The performance of the new detector is assessed,and analyzed in comparison with other detectors.The results show that,the proposed detector can provide enhanced rejection capability in the case of mismatch,but the performance of the detector is slightly lost under the condition of matching.
基金supported by the National Natural Science Foundation of China (52102198)the Key R&D and Promotion Projects of Henan Province (212102310016)+1 种基金the Initial Scientific Research Fund of Ph.D.in Anyang Institute of Technology (BSJ2021043)the Initial Scientific Research Fund of Postdoctor in Anyang Institute of Technology (BHJ2022008)。
文摘Composite polymer electrolytes(CPEs)are considered to be the most promising to break through the performance and safety limitations of traditional lithium-ion batteries because of their excellent electrochemical and mechanical properties.Aiming at the performance limitations of the most common polyether matrix such as poly(ethylene oxide)(PEO),a novel poly(cyclocarbonate-ether)polymer matrix was prepared by in-situ thermal curing,the weaker interaction between its C=O bond and Li^(+)can promote the rapid transport of Li^(+).Adding ionic liquid and active filler LLZTO to the matrix can synergistically reduce the crystallinity of matrix and promote the dissociation of lithium salts.In addition,a 3D functional skeleton made of polyacrylonitrile(PAN)and lithium fluoride(LiF)can greatly improve the mechanical strength of polymer matrix after cold pressing,and Li F is also conducive to interface stability.The thickness of the optimal sample(VP6L/CPL)was only 25μm,and its ionic conductivity,lithium ion transference number,and electrochemical stability window were as high as 7.17×10^(-4)S cm^(-1)(25℃),0.54 and 5.4 V,respectively,while the mechanical strength reaches 6.1 MPa,which can fully inhibit the growth of lithium dendrites.The excellent electrochemical performance and mechanical strength enable the assembled Li|VP6L/CPL|Li battery to be continuously charged for over 200 h and cycled stably for more than 2300 h,and Li|VP6L/CPL|LFP battery can be stably cycled for more than 400 and 550 cycles at 1 C(40℃)and 0.5 C(25℃),respectively.
基金supported by National Nature Science Foundation of China(11701168,11601144 and 11626096)Hunan Provincial Natural Science Foundation of China(2018JJ3108,2018JJ3109 and 2018JJ4062)+1 种基金Scientific Research Fund of Hunan Provincial Education Department(16K026 and YB2016B033)China Postdoctoral Science Foundation(2018M631403)
文摘In this paper, a new kind of alternating direction implicit(ADI) Crank-Nicolsontype orthogonal spline collocation(OSC) method is formulated for the two-dimensional fractional evolution equation with a weakly singular kernel arising in the theory of linear viscoelasticity. The novel OSC method is used for the spatial discretization, and ADI Crank-Nicolsontype method combined with the second order fractional quadrature rule are considered for the temporal component. The stability of proposed scheme is rigourously established, and nearly optimal order error estimate is also derived. Numerical experiments are conducted to support the predicted convergence rates and also exhibit expected super-convergence phenomena.
文摘In this paper, we investigate the effect of layer thickness on the residual stresses of copper indium gallium diselenide (CIGS) solar cells with polyimide substrate caused by CIGS layer deposition at 400?C and then cooling down to room temperature using the Finite Element Method (FEM). Moreover, we also examined the effect of layer thickness on residual stress of CIGS solar cells after cooling down to room temperature from the hotspot temperatures of 200?C, 300?C, and 400?C. Our simulated CIGS is composed of five layers: ZnO, CdS, CIGS, Mo, and PI substrate. We were able to quantify the effect of each layer’s thickness and hotspot temperature on the average stresses of each layer for the CIGS solar cells. We found that the PI substrate layer has the most significant effect on the residual stress of CIGS solar cells. Our simulation results reveal that the stress type (tensile vs. compressive) and the magnitude of stress of the CIGS layer (main absorber layer) can be controlled by changing the thickness of the PI substrate while applying a heat to CIGS solar cells. Quantitative analysis of relationship between layer thickness and thermo-mechanical stress of thin film solar cells can help solar cell manufacturers design more robust and reliable solar cells. For example, fabricating PI layer thickness less than 17 μm can improve the performance of CIGS solar cells by nullifying the compressive residual stress in the CIGS absorber layer.
基金Project supported by the National Basic Research Program of China(Grant No.2011CBA00304)the National Natural Science Foundation of China(Grant No.60836001)the Research Fund from Beijing Innovation Center for Future Chip
文摘Dynamical decoupling is widely used in many quantum computing systems to combat decoherence. In a practical superconducting quantum system, imperfections can plague decoupling performance. In this work, imperfections in a superconducting qubit and its control system are modeled via modified Hamiltonian and collapse operator. A master equation simulation is carried out on the qubit under 1/f environment noise spectrum. The average dephasing rate of qubit is extracted to characterize the impact of different imperfections on the decoupling from dephasing. We find that the precision of pulse position, on–off ratio, and filtering effect are most critical. Bounded pulses have weaker impact,while variation in pulse width and qubit relaxation are insignificant. Consequently, alternative decoupling protocols, jitter mitigation, cascaded mixers, and pulse shaping can be conducive to the performance of decoupling. This work may assist the analysis and optimization of dynamical decoupling on noisy superconducting quantum systems.
基金Project supported by the National Natural Science Foundation of China(Grants Nos.11934010,U1801661,and 12174329)the Zhejiang Province Program for Science and Technology(Grant No.2020C01019)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.2021FZZX001-02)the China Postdoctoral Science Foundation(Grant No.2019M660137)
文摘When there is a certain amount of field inhomogeneity,the biased ferrimagnetic crystal can exhibit the higher-order magnetostatic(HMS)mode in addition to the uniform-precession Kittel mode.In cavity magnonics,we show the nonlinearity and heating-induced frequency shifts of the Kittel mode and HMS mode in a yttrium-iron-garnet(YIG)sphere.When the Kittel mode is driven to generate a certain number of excitations,the temperature of the whole YIG sample rises and the HMS mode can display an induced frequency shift,and vice versa.This cross effect provides a new method to study the magnetization dynamics and paves a way for novel cavity magnonic devices by including the heating effect as an operational degree of freedom.
基金supported by the National Key Research and Development Program of China(No.2017YFC1308604)the Shanghai Program for Innovative Research Team in Universities,the National Natural Science Foundation of China(No.81802903,81672820,81772563,81930074 and 81872356)+2 种基金the NSFC Program of International Cooperation and Exchanges(No.81120108016)the National Key Basic Research Program of China(No.2013CB910500 and 2014CB542101)China National Key Projects for Infectious Disease(No.2012ZX10002-012).
文摘Enolase 2(ENO2)is a key glycolytic enzyme in the metabolic process of glycolysis,but its potential function in pancreatic ductal adenocarcinoma(PDAC)is unclear.In this study,we observed a significant overexpression of ENO2 in PDAC tissues,and its expression was correlated with metastasis and poor prognosis in PDAC patients.K394 was identified as a major acetylation site in ENO2 that regulates its enzymatic activity,cell metabolism and PDAC progression.Knockdown of ENO2 suppressed tumor growth and liver metastasis in PDAC.Re-expression of wild-type(WT)ENO2,but not the K394 acetylation mimetic mutant,could reverse the decreased tumor malignancy.We further characterized histone deacetylase 3(HDAC3)and P300/CBP-associated factor(PCAF)as the potential deacetylase and acetyltransferase for ENO2,respectively.HDAC3-mediated deacetylation was shown to lead to ENO2 activation and enhancement of glycolysis.Importantly,insulin-like growth factor-1(IGF-1)was found to decrease K394 acetylation and stimulate ENO2 activity in a dose-and time-dependent manner.The PI3K/AKT/mTOR pathway facilitated the phosphorylation of HDAC3 on S424,which promoted K394 deacetylation and activation of ENO2.Linsitinib,an oral small-molecule inhibitor of IGF-1R,could inhibit IGF-1-induced ENO2 deacetylation by HDAC3 and the PI3K/AKT/mTOR pathway.Furthermore,linsitinib showed a different effect on the growth and metastasis of PDAC depending on the overexpression of WT versus K394-mutant ENO2.Our results reveal a novel mechanism by which acetylation negatively regulates ENO2 activity in the metastasis of PDAC by modulating glycolysis.Blockade of IGF-1-induced ENO2 deacetylation represents a promising strategy to prevent the development of PDAC.
基金Supported by the State Key Program of National Natural Science Foundation of China(Grant No.71931004)the State Key Program in the Ma jor Research Plan of National Natural Science Foundation of China(Grant No.91546202)。
文摘Length-biased data are encountered in many fields,including economics,engineering and epidemiological cohort studies.There are two main challenges in the analysis of such data:the assumption of independent censoring is violated and the assumed model for the underlying population is no longer satisfied for the observed data.In this paper,a proportional mean residual life varyingcoefficient model for length-biased data is considered and a local pseudo likelihood method is proposed for estimating the coefficient functions in the model.Asymptotic properties are investigated for the proposed estimators.The finite sample performance of the proposed methodology is demonstrated by simulation studies.Finally,the method is applied to a real data set concerning the Academy Awards.
基金supported by the National Science Foundation(Nos.1654746 and 1810453).
文摘Tip-enhanced Raman spectroscopy(TERS)imaging is a super-resolution imaging technique that features the merits of both surface-enhanced Raman spectroscopy(SERS)and scanning probe microscopy(SPM),such as the high chemical sensitivity from the former and the nanoscale spatial resolution from the latter.These advantages make TERS an essential nanospectroscopic characterization technique for chemical analysis,materials science,bio-sensing,etc.TERS probes,the most critical factor determining the TERS imaging quality,are expected to provide a highly confined electromagnetic hotspot with a minimized scattering background for the generation of Raman signals with high spatial resolution.After two decades of development,numerous probe design concepts have been proposed and demonstrated.This review provides a comprehensive overview of the state-of-the-art TERS probe designs,from the working mechanism to the practical performance.We start with reviewing the recent development of TERS configurations and the corresponding working mechanisms,including the SPM platforms,optical excitation/collection techniques,and probe preparation methods.We then review the emerging novel TERS probe designs,including the remote-excitation probes,the waveguide-based nanofocusing probes,the metal-coated nanofocusing probes,the nanowire-assisted selective-coupling probes,and the tapered metal-insulator-metal probes.Our discussion focuses on a few critical aspects,including the surface-plasmon-polariton(SPP)hotspot excitation technique,conversion efficiency,working frequency,and controllability.In the end,we review the latest TERS applications and give a perspective on the future of TERS.
基金supported by the National Natural Ascience Foundation of China(No.31821003 to HX)the China Ministry of Science and Technology(No.2018AAA0100300 to HX).
文摘Objective:Although the neurological and olfactory symptoms of coronavirus disease 2019 have been identified,the neurotropic properties of the causative virus,severe acute respiratory syndrome-associated coronavirus 2(SARS-CoV-2),remain unknown.We sought to identify the susceptible cell types and potential routes of SARS-CoV-2 entry into the central nervous system,olfactory system,and respiratory system.Methods:We collected single-cell RNA data from normal brain and nasal epithelium specimens,along with bronchial,tracheal,and lung specimens in public datasets.The susceptible cell types that express SARS-CoV-2 entry genes were identified using single-cell RNA sequencing and the expression of the key genes at protein levels was verified by immunohistochemistry.We compared the coexpression patterns of the entry receptor angiotensin-converting enzyme 2(ACE2)and the spike protein priming enzyme transmembrane serine protease(TMPRSS)/cathepsin L among the specimens.Results:The SARS-CoV-2 entry receptor ACE2 and the spike protein priming enzyme TMPRSS/cathepsin L were coexpressed by pericytes in brain tissue;this coexpression was confirmed by immunohistochemistry.In the nasal epithelium,ciliated cells and sustentacular cells exhibited strong coexpression of ACE2 and TMPRSS.Neurons and glia in the brain and nasal epithelium did not exhibit coexpression of ACE2 and TMPRSS.However,coexpression was present in ciliated cells,vascular smooth muscle cells,and fibroblasts in tracheal tissue;ciliated cells and goblet cells in bronchial tissue;and alveolar epithelium type 1 cells,AT2 cells,and ciliated cells in lung tissue.Conclusion:Neurological symptoms in patients with coronavirus disease 2019 could be associated with SARS-CoV-2 invasion across the blood-brain barrier via pericytes.Additionally,SARS-CoV-2-induced olfactory disorders could be the result of localized cell damage in the nasal epithelium.
基金This work was supported by the National Natural Science Foundation of China(81902390 and 81902952)the National Key Research and Development Program of China(2017YFC1308604).
文摘Background The efficacy of immune checkpoint inhibitors(ICIs),such as programmed cell death protein-1(PD-1)or its ligand 1(PD-L1)antibody,in hepatocellular carcinoma(HCC)is limited,and it is recommended that they be combined with other therapies.We evaluated the combination of pegylated interferon-α(Peg-IFNα)with PD-1 blockade in HCC mouse models.Methods We analyzed the effects of Peg-IFNαon tumor-infiltrating immune cells and PD-1 expression in the HCC immune microenvironment and examined the underlying mechanism of its unique effect on the PD-1 pathway.The in vivo efficacy of anti-PD-1 and Peg-IFNαwas evaluated in both subcutaneous and orthotopic mouse models of HCC.Results The combination of Peg-IFNαwith PD-1 blockade dramatically enhanced T-cell infiltration,improved the efficacy of PD-1 antibody and prolonged mouse survival compared with PD-1 antibody monotherapy.Mechanistically,Peg-IFNαcould recruit cytotoxic CD8+T cells to infiltrate the HCC microenvironment by inducing tumor cells to secrete the chemokine CCL4.Nevertheless,the HCC microenvironment quickly overcame the immune responses by upregulating PD-1 expression in CD8+T cells via the IFNα-IFNAR1-JAK1-STAT3 signaling pathway.The combination of PD-1 blockade with Peg-IFNαcould restore the cytotoxic capacity of CD8+T cells and exerted a significant synergistic effect on HCC.Conclusion These results indicate that in addition to initiating the antitumor immune response itself,Peg-IFNαcan also generate a microenvironment favoring PD-1 blockade.Thus,the combination of Peg-IFNαand PD-1 blockade can be a promising strategy for HCC.
基金supported by the National Key R&D Program of China(2016YFA0301302)the National Natural Science Foundation of China(61435001,11654003,11474011)High-performance Computing Platform of Peking University
文摘Spontaneous symmetry breaking has revolutionized the understanding in numerous fields of modern physics. Here, we theoretically demonstrate the spontaneous time-reversal symmetry breaking in a cavity quantum electrodynamics system in which an atomic ensemble interacts coherently with a single resonant cavity mode. The interacting system can be effectively described by two coupled oscillators with positive and negative mass, when the two-level atoms are prepared in their excited states. The occurrence of symmetry breaking is controlled by the atomic detuning and the coupling to the cavity mode,which naturally divides the parameter space into the symmetry broken and symmetry unbroken phases.The two phases are separated by a spectral singularity, a so-called exceptional point, where the eigenstates of the Hamiltonian coalesce. When encircling the singularity in the parameter space, the quasiadiabatic dynamics shows chiral mode switching which enables topological manipulation of quantum states.
文摘Introduction:National Notifiable Disease Reporting System(NNDRS)plays an important role in the early detection and control of tuberculosis(TB)in China.This study analyzed the epidemiological characteristics of pulmonary tuberculosis(PTB)in Kashgar Prefecture,Xinjiang Uygur Autnomous Region,China from 2011 to 2020 to provide a scientific basis for developing TB control strategies and measures in Kashgar.Methods:The data were collected from the NNDRS,which included the geographical distribution,age,sex,occupation,and pathogenic classification of reported PTB cases in 12 counties/cities of Kashgar Prefecture from 2011 to 2020.Descriptive statistics were used to describe the characteristic of PTB epidemic in Kashgar.Results:There were 189,416 PTB cases reported during 2011–2020,with a mean annual PTB case notification rate(CNR)of 451.29/100,000.A rising trend in the rate of reported PTB between 2011 and 2017(χ2 trend=26.09,P<0.01)and a declining trend between 2018 and 2020(χ2 trend=314.44,P<0.01)were observed.The months with the highest reported number of PTB cases were March to May and November to December.The mean annual rate of reported PTB was 451.88/100,000 for males and 450.67/100,000 for females.In addition,19.76%of patients were bacteriologically-confirmed(Bac+)cases(37,425/189,416),and the mean annual Bac+CNR was 89.17/100,000,rising from 64.76/100,000 in 2011 to 139.12/100,000 in 2020(χ^(2)_(trend)=74.44,P<0.01).Conclusions:The CNR of reported PTB in Kashgar showed a significant declining trend in the past three years.Males,elderly population,winter and spring,and farmers as an occupation were the main factors associated with high incidence of tuberculosis in Kashgar.Targeted prevention and treatment of TB should be strengthened in key groups in this region.
基金supported by the National Natural Science Foundation of China(10971062)the Scientific Research Foundation of Central South University of Forestry and Technology.
文摘This paper is concerned with a compact difference scheme with the truncation error of order 3/2 for time and order 4 for space to an evolution equation with a weakly singular kernel.The integral term is treated by means of the second order convolution quadrature suggested by Lubich.The stability and convergence are proved by the energy method.A numerical experiment is reported to verify the theoretical predictions.
基金This material is based upon work supported by the National Science Foundation under gant No.CHE-1654794.The authors acknowledge Prof.Yadong Yin from the Department of Chemistry,UC Riverside for helpful discussion.
文摘Silver nanowires (AgNWs) hold great promise for applications in wearable electronics, flexible solar cells, chemical and biological sensors, photonic/plasmonic circuits, and scanning probe microscopy (SPM) due to their unique plasmonic, mechanical, and electronic properties. However, the lifetime, reliability, and operating conditions of AgNW-based devices are significantly restricted by their poor chemical stability, limiting their commercial potentials. Therefore, it is crucial to create a reliable oxidation barrier on AgNWs that provides long-term chemical stability to various optical, electrical, and mechanical devices while maintaining their high performance. Here we report a room-temperature solution-phase approach to grow an ultra-thin, epitaxial gold coating on AgNWs to effectively shield the Ag surface from environmental oxidation. The Ag@Au core-shell nanowires (Ag@Au NWs) remain stable in air for over six months, under elevated temperature and humidity (80 °C and 100% humidity) for twelve weeks, in physiological buffer solutions for three weeks, and can survive overnight treatment of an oxidative solution (2% H2O2). The Ag@Au core-shell NWs demonstrated comparable performance as pristine AgNWs in various electronic, optical, and mechanical devices, such as transparent mesh electrodes, surface-enhanced Raman spectroscopy (SERS) substrates, plasmonic waveguides, plasmonic nanofocusing probes, and high-aspect-ratio, high-resolution atomic force microscopy (AFM) probes. These Au@Ag core-shell NWs offer a universal solution towards chemically-stable AgNW-based devices without compromising material property or device performance.
基金We thank Linran Fan,Qi-Tao Cao,and Mian Zhang for fruitful discussions.This work was supported by the National Key R&D Program of China(Grant Nos.2016YFA0301302 and 2018YFB2200401)NSFC(Grant Nos.11825402,61435001,11654003,and 11674200),and High-Performance Computing Platform of Peking University.The authors declare that they have no competing financial interests.
文摘Synchronization is of importance in both fundamental and applied physics,but its demonstration at the micro/nanoscale is mainly limited to low-frequency oscillations such as mechanical resonators.We report the synchronization of two coupled optical microresonators,in which the high-frequency resonances in the optical domain are aligned with reduced noise.It is found that two types of synchronization regimes emerge with either the first-or second-order transition,both presenting a process of spontaneous symmetry breaking.In the second-order regime,the synchronization happens with an invariant topological character number and a larger detuning than that of the first-order case.Furthermore,an unconventional hysteresis behavior is revealed for a time-dependent coupling strength,breaking the static limitation and the temporal reciprocity.The synchronization of optical microresonators offers great potential in reconfigurable simulations of manybody physics and scalable photonic devices on a chip.
基金This study was supported by grants from the National Nature Science Foundation of China(No.81874143)the Beijing Natural Science Foundation(No.7192035).
文摘Since the Chinese economic reform in 1978,its medical field has made remarkable progress in the past 40 years.In most medical fields,China’s diagnosis and treatment methods are comparable to the international high standards.In recent years,with the continuous expansion of the medical research team and the improvement of laboratory research equipment and methods,China has achieved some influential and internationally recognized research outcomes.However,overall,China still lags behind developed countries in terms of high-level original medical research,especially in high evidence-based medical research(1).
基金supported by the National Natural Science Foundation of China (61435007 and 11574176)the Joint Fund of the Ministry of Education of China (6141A02011604)
文摘Quantum entanglement,since proposed by Einstein,Podolsky and Rosen(EPR)[1]and further explored by Schr?dinger[2]in1935,has always been the focus of quantum physics realm.The EPR paradox revealed the conflict between quantum theory and local realism.Almost 30 years later,in 1964,Bell first came up with the prototype of a family of inequalities,which was later called Bell inequality[3,4],to express certain limitation that every local clas-
