D2D(Device to Device)通信可实现距离相近的用户设备直接通信,有效地提升系统的吞吐量,获得高频谱效率和能量效率,但D2D通信共享蜂窝网络频谱资源时,会造成蜂窝网络与D2D链路严重的层间干扰.为减少层间干扰带来的影响,提出一种基于Q学...D2D(Device to Device)通信可实现距离相近的用户设备直接通信,有效地提升系统的吞吐量,获得高频谱效率和能量效率,但D2D通信共享蜂窝网络频谱资源时,会造成蜂窝网络与D2D链路严重的层间干扰.为减少层间干扰带来的影响,提出一种基于Q学习的联合资源分配与功率控制算法.从Q学习的角度来构建数学模型,将蜂窝网络中的多个D2D用户对视为多智能体学习者,利用历史状态(历史吞吐量和功率值),不需要精确的信道状态信息(Channel State Information,CSI)和互干扰等先验知识,通过Q学习算法,学习得到分布式的信道选择和功率控制的联合最优策略.可以动态调整D2D用户功率,在保证蜂窝用户服务质量的前提下,通过D2D功率控制获得最大化系统吞吐量.仿真结果表明,基于Q学习的联合资源分配与功率控制的算法有效提高了系统的吞吐量.展开更多
主要研究了单位圆盘上l^2值D_(μ,q)函数,得到了l^2值D_(μ,q)函数的收敛性,若f(z)=sum from n=1 to∞x_nz^n∈D_(μ,q),0<μ<1,q>(2n)/μ,则对几乎所有的{ε_α}有f_ω(z)∈H~∞.这推广了标量值D_(μ,q)函数的性质,在此过程中...主要研究了单位圆盘上l^2值D_(μ,q)函数,得到了l^2值D_(μ,q)函数的收敛性,若f(z)=sum from n=1 to∞x_nz^n∈D_(μ,q),0<μ<1,q>(2n)/μ,则对几乎所有的{ε_α}有f_ω(z)∈H~∞.这推广了标量值D_(μ,q)函数的性质,在此过程中,利用了Banach空间几何学的知识.展开更多
The proposed DAC consists of a unit current-cell matrix for 8MSBs and a binary-weighted array for 4LSBs,trading-off between the precision,speed,and size of the chip.In order to ensure the linearity of the DAC,a double...The proposed DAC consists of a unit current-cell matrix for 8MSBs and a binary-weighted array for 4LSBs,trading-off between the precision,speed,and size of the chip.In order to ensure the linearity of the DAC,a double Centro symmetric current matrix is designed by the Q2 random walk strategy.To achieve better dynamic performance,a latch is added in front of the current switch to change the input signal,such as its optimal cross-point and voltage level.For a 12bit resolution,the converter reaches an update rate of 300MHz.展开更多
Although numerous metal halide perovskite materials have been investigated in the field of optoelectronic,the development of perovskite heterojunctions with exotic structures is still rare.Herein,we report the epitaxi...Although numerous metal halide perovskite materials have been investigated in the field of optoelectronic,the development of perovskite heterojunctions with exotic structures is still rare.Herein,we report the epitaxial growth of quasi-two-dimensional(Q-2D)perovskites on methylammonium lead iodide(MAPbI_(3))single crystals to form perovskite heterojunctions with interfacial bonding.The MAPbI_(3)adjacent to epitaxial Q-2D perovskite shows blue shifted photoluminescence with shortened lifetime,which becomes significant with the reduced layer number of the Q-2D perovskites.Our findings suggest the presence of an interfacial strain gradient leading to enhanced photocarrier separation.Accordingly,compared to the MAPbI_(3)single crystal detector,the BA_(2)MAPb_(2)I_(7)/MAPbI_(3)(BA:n-butylamine)heterojunction-based photodetector demonstrates a bandpass detecting property and exhibits 5 times enhanced external quantum efficiency and 83 times enhanced specific detectivity(D*=3.26×10^(11)Jones).Remarkably,the unencapsulated BA_(2)MAPb_(2)I_(7)/MAPbI_(3)heterojunction is stable in ambient condition for>300 days.The Q-2D/3D heterojunction shows suppressed ion inter-diffusion due to the presence of Q-2D phase.展开更多
In recent years,Perovskite Light-Emitting Diodes(PeLEDs)have received considerable attention in academia.However,with the development of PeLEDs,commercial applications of full-color PeLED technology are largely limite...In recent years,Perovskite Light-Emitting Diodes(PeLEDs)have received considerable attention in academia.However,with the development of PeLEDs,commercial applications of full-color PeLED technology are largely limited by the progress of blue-emitting devices,due to the uncontrollably accurate composition,unstable properties,and low luminance.In this article,we add Cesium chloride(CsCl)to the quasi-two-dimensional(quasi-2D)perovskite precursor solution and achieve the relatively blue shifts of PeLED emission peak by introducing chloride ions for photoluminescence(PL)and electroluminescence(EL).We also found that the introduction of chlorine ions can make quasi-2D perovskite films thinner with smoother surface of 0.408 nm.It is interesting that the EL peaks and intensities of PeLED are adjustable under different driving voltages in high concentration chlorine-added perovskite devices,and different processes of photo-excited,photo-quenched,and photo-excited occur sequentially with the increasing driving voltage.Our work provides a path for demonstrating full-color screens in the future.展开更多
Halide perovskites have been extensively studied for use as light-emitting diodes(LEDs)in next-generation displays due to their beneficial characteristics,including their high color purity and wide color gamut.Halide ...Halide perovskites have been extensively studied for use as light-emitting diodes(LEDs)in next-generation displays due to their beneficial characteristics,including their high color purity and wide color gamut.Halide perovskites can be categorized into four representative structures:three-dimensional(3D)bulk,two-dimensional(2D),quasi-two-dimensional(quasi-2D),and quantum dot(QD).Recently,excellent advances in the performance of perovskite LEDs(PeLEDs),especially those with quasi-2D and QD architectures,have been demonstrated with the incorporation of organic chain ligands.Ligands can both modify the structure of PeLEDs,such as forming multi-quantum wells in quasi-2D PeLEDs and essential passivation layers in QD PeLEDs,and also enhance their optical performance.The appropriate use of ligands in PeLEDs can thus lead to greater luminescence,current efficiency,power efficiency,and external quantum efficiency.In this review,the principal roles of ligands in quasi-2D and QD PeLEDs are systematically summarized.Furthermore,current limitations and future perspectives are discussed in detail.展开更多
γ-Aminobutyric acid（GABA）,plays a key role in all stages of life,also is considered the main inhibitory neurotransmitter.GABA activates two kind of membrane receptors known as GABAA and GABAB,the first one is respo...γ-Aminobutyric acid（GABA）,plays a key role in all stages of life,also is considered the main inhibitory neurotransmitter.GABA activates two kind of membrane receptors known as GABAA and GABAB,the first one is responsible to render tonic inhibition by pentameric receptors containing α4-6,β3,δ,or ρ1-3 subunits,they are located at perisynaptic and/or in extrasynaptic regions.The biophysical properties of GABAA tonic inhibition have been related with cellular protection against excitotoxic injury and cell death in presence of excessive excitation.On this basis,GABAA tonic inhibition has been proposed as a potential target for therapeutic intervention of Huntington＇s disease.Huntington＇s disease is a neurodegenerative disorder caused by a genetic mutation of the huntingtin protein.For experimental studies of Huntington＇s disease mouse models have been developed,such as R6/1,R6/2,Hdh Q92,Hdh Q150,as well as YAC128.In all of them,some key experimental reports are focused on neostriatum.The neostriatum is considered as the most important connection between cerebral cortex and basal ganglia structures,its cytology display two pathways called direct and indirect constituted by medium sized spiny neurons expressing dopamine D1 and D2 receptors respectively,they display strong expression of many types of GABAA receptors,including tonic subunits.The studies about of GABAA tonic subunits and Huntington＇s disease into the neostriatum are rising in recent years,suggesting interesting changes in their expression and localization which can be used as a strategy to delay the cellular damage caused by the imbalance between excitation and inhibition,a hallmark of Huntington＇s disease.展开更多
Large eddy simulation （LES） using the Smagorinsky eddy viscosity model is added to the two-dimensional nine velocity components （D2Q9） lattice Boltzmann equation （LBE） with multi-relaxation-time （MRT） to simul...Large eddy simulation （LES） using the Smagorinsky eddy viscosity model is added to the two-dimensional nine velocity components （D2Q9） lattice Boltzmann equation （LBE） with multi-relaxation-time （MRT） to simulate incompressible turbulent cavity flows with the Reynolds numbers up to 1 × 10^7. To improve the computation efficiency of LBM on the numerical simulations of turbulent flows, the massively parallel computing power from a graphic processing unit （GPU） with a computing unified device architecture （CUDA） is introduced into the MRT-LBE-LES model. The model performs well, compared with the results from others, with an increase of 76 times in computation efficiency. It appears that the higher the Reynolds numbers is, the smaller the Smagorinsky constant should be, if the lattice number is fixed. Also, for a selected high Reynolds number and a selected proper Smagorinsky constant, there is a minimum requirement for the lattice number so that the Smagorinsky eddy viscosity will not be excessively large.展开更多
文摘D2D(Device to Device)通信可实现距离相近的用户设备直接通信,有效地提升系统的吞吐量,获得高频谱效率和能量效率,但D2D通信共享蜂窝网络频谱资源时,会造成蜂窝网络与D2D链路严重的层间干扰.为减少层间干扰带来的影响,提出一种基于Q学习的联合资源分配与功率控制算法.从Q学习的角度来构建数学模型,将蜂窝网络中的多个D2D用户对视为多智能体学习者,利用历史状态(历史吞吐量和功率值),不需要精确的信道状态信息(Channel State Information,CSI)和互干扰等先验知识,通过Q学习算法,学习得到分布式的信道选择和功率控制的联合最优策略.可以动态调整D2D用户功率,在保证蜂窝用户服务质量的前提下,通过D2D功率控制获得最大化系统吞吐量.仿真结果表明,基于Q学习的联合资源分配与功率控制的算法有效提高了系统的吞吐量.
文摘主要研究了单位圆盘上l^2值D_(μ,q)函数,得到了l^2值D_(μ,q)函数的收敛性,若f(z)=sum from n=1 to∞x_nz^n∈D_(μ,q),0<μ<1,q>(2n)/μ,则对几乎所有的{ε_α}有f_ω(z)∈H~∞.这推广了标量值D_(μ,q)函数的性质,在此过程中,利用了Banach空间几何学的知识.
文摘The proposed DAC consists of a unit current-cell matrix for 8MSBs and a binary-weighted array for 4LSBs,trading-off between the precision,speed,and size of the chip.In order to ensure the linearity of the DAC,a double Centro symmetric current matrix is designed by the Q2 random walk strategy.To achieve better dynamic performance,a latch is added in front of the current switch to change the input signal,such as its optimal cross-point and voltage level.For a 12bit resolution,the converter reaches an update rate of 300MHz.
基金the National Natural Science Foundation of China(Nos.52273202,62104261,51673218,and 62004066)the National Key Research and Development Program of China(No.2022YFB3803300)+4 种基金the Natural Science Program of Xinjiang Uygur Autonomous Region(No.2023D01D03)the Major Scientific and Technological Project of Changsha(No.kq2301002)the Program of Hundreds of Talents of Hunan Province and Changsha Municipal Natural Science Foundation(No.KQ2007027)the National Key Research and Development Program of China(No.2023YFE0116800)the Beijing Natural Science Foundation(No.IS23037).
文摘Although numerous metal halide perovskite materials have been investigated in the field of optoelectronic,the development of perovskite heterojunctions with exotic structures is still rare.Herein,we report the epitaxial growth of quasi-two-dimensional(Q-2D)perovskites on methylammonium lead iodide(MAPbI_(3))single crystals to form perovskite heterojunctions with interfacial bonding.The MAPbI_(3)adjacent to epitaxial Q-2D perovskite shows blue shifted photoluminescence with shortened lifetime,which becomes significant with the reduced layer number of the Q-2D perovskites.Our findings suggest the presence of an interfacial strain gradient leading to enhanced photocarrier separation.Accordingly,compared to the MAPbI_(3)single crystal detector,the BA_(2)MAPb_(2)I_(7)/MAPbI_(3)(BA:n-butylamine)heterojunction-based photodetector demonstrates a bandpass detecting property and exhibits 5 times enhanced external quantum efficiency and 83 times enhanced specific detectivity(D*=3.26×10^(11)Jones).Remarkably,the unencapsulated BA_(2)MAPb_(2)I_(7)/MAPbI_(3)heterojunction is stable in ambient condition for>300 days.The Q-2D/3D heterojunction shows suppressed ion inter-diffusion due to the presence of Q-2D phase.
基金supported by the National Key Research and Development Program of China(No.2018YFB2200103)the National Natural Science Foundation of China(Nos.61875186 and 61975196)+2 种基金the Project of the Natural Science Foundation of Beijing(No.Z160002)the Key Research Projects of Beijing Information Science and Technology University(BISTU)(Nos.2019-22,2019-23,2019-27)the Beijing Key Laboratory for Sensors of BISTU(No.2019CGKF007)。
文摘In recent years,Perovskite Light-Emitting Diodes(PeLEDs)have received considerable attention in academia.However,with the development of PeLEDs,commercial applications of full-color PeLED technology are largely limited by the progress of blue-emitting devices,due to the uncontrollably accurate composition,unstable properties,and low luminance.In this article,we add Cesium chloride(CsCl)to the quasi-two-dimensional(quasi-2D)perovskite precursor solution and achieve the relatively blue shifts of PeLED emission peak by introducing chloride ions for photoluminescence(PL)and electroluminescence(EL).We also found that the introduction of chlorine ions can make quasi-2D perovskite films thinner with smoother surface of 0.408 nm.It is interesting that the EL peaks and intensities of PeLED are adjustable under different driving voltages in high concentration chlorine-added perovskite devices,and different processes of photo-excited,photo-quenched,and photo-excited occur sequentially with the increasing driving voltage.Our work provides a path for demonstrating full-color screens in the future.
基金supported by a National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(NRF-2021R1A2C4002045 and 2021R1A4A2001687).
文摘Halide perovskites have been extensively studied for use as light-emitting diodes(LEDs)in next-generation displays due to their beneficial characteristics,including their high color purity and wide color gamut.Halide perovskites can be categorized into four representative structures:three-dimensional(3D)bulk,two-dimensional(2D),quasi-two-dimensional(quasi-2D),and quantum dot(QD).Recently,excellent advances in the performance of perovskite LEDs(PeLEDs),especially those with quasi-2D and QD architectures,have been demonstrated with the incorporation of organic chain ligands.Ligands can both modify the structure of PeLEDs,such as forming multi-quantum wells in quasi-2D PeLEDs and essential passivation layers in QD PeLEDs,and also enhance their optical performance.The appropriate use of ligands in PeLEDs can thus lead to greater luminescence,current efficiency,power efficiency,and external quantum efficiency.In this review,the principal roles of ligands in quasi-2D and QD PeLEDs are systematically summarized.Furthermore,current limitations and future perspectives are discussed in detail.
基金the programs for the postdoctoral fellowships-Chilean CONICYT-FONDECYT#3140218,Mexican CONACYT#164978 and DID-UACh S-2015-81Sistema Nacional de Investigadores#58512 to Abraham Rosas-Arellano+2 种基金supported by USACH PhD fellowshipsupported with a PhD fellowship from CONACYT(#299627)FONDECYT grants 1151206 and 1110571 to Maite A.Castro
文摘γ-Aminobutyric acid（GABA）,plays a key role in all stages of life,also is considered the main inhibitory neurotransmitter.GABA activates two kind of membrane receptors known as GABAA and GABAB,the first one is responsible to render tonic inhibition by pentameric receptors containing α4-6,β3,δ,or ρ1-3 subunits,they are located at perisynaptic and/or in extrasynaptic regions.The biophysical properties of GABAA tonic inhibition have been related with cellular protection against excitotoxic injury and cell death in presence of excessive excitation.On this basis,GABAA tonic inhibition has been proposed as a potential target for therapeutic intervention of Huntington＇s disease.Huntington＇s disease is a neurodegenerative disorder caused by a genetic mutation of the huntingtin protein.For experimental studies of Huntington＇s disease mouse models have been developed,such as R6/1,R6/2,Hdh Q92,Hdh Q150,as well as YAC128.In all of them,some key experimental reports are focused on neostriatum.The neostriatum is considered as the most important connection between cerebral cortex and basal ganglia structures,its cytology display two pathways called direct and indirect constituted by medium sized spiny neurons expressing dopamine D1 and D2 receptors respectively,they display strong expression of many types of GABAA receptors,including tonic subunits.The studies about of GABAA tonic subunits and Huntington＇s disease into the neostriatum are rising in recent years,suggesting interesting changes in their expression and localization which can be used as a strategy to delay the cellular damage caused by the imbalance between excitation and inhibition,a hallmark of Huntington＇s disease.
基金supported by College of William and Mary,Virginia Institute of Marine Science for the study environment
文摘Large eddy simulation （LES） using the Smagorinsky eddy viscosity model is added to the two-dimensional nine velocity components （D2Q9） lattice Boltzmann equation （LBE） with multi-relaxation-time （MRT） to simulate incompressible turbulent cavity flows with the Reynolds numbers up to 1 × 10^7. To improve the computation efficiency of LBM on the numerical simulations of turbulent flows, the massively parallel computing power from a graphic processing unit （GPU） with a computing unified device architecture （CUDA） is introduced into the MRT-LBE-LES model. The model performs well, compared with the results from others, with an increase of 76 times in computation efficiency. It appears that the higher the Reynolds numbers is, the smaller the Smagorinsky constant should be, if the lattice number is fixed. Also, for a selected high Reynolds number and a selected proper Smagorinsky constant, there is a minimum requirement for the lattice number so that the Smagorinsky eddy viscosity will not be excessively large.
