Effect of Surface Potential Barrier on the Electron Energy Distribution of NEA Photocathodes

By calculating the energy distribution of electrons reaching the photocathode surface and solving the Schrodinger equation that describes the behavior of an electron tunneling through the surface potential barrier,we obtain an equation to calculate the emitted electron energy distribution of transmission-mode NEA GaAs photocathodes. Accord- ing to the equation,we study the effect of cathode surface potential barrier on the electron energy distribution and find a significant effect of the barrier-Ⅰ thickness or end height,especially the thickness,on the quantum efficiency of the cath- ode. Barrier Ⅱ has an effect on the electron energy spread, and an increase in the vacuum level will lead to a narrower electron energy spread while sacrificing a certain amount of cathode quantum efficiency. The equation is also used to fit the measured electron energy distribution curve of the transmission-mode cathode and the parameters of the surface barri- er are obtained from the fitting. The theoretical curve is in good agreement with the experimental curve.

Stress-induced potential barriers and charge distributions in a piezoelectric semiconductor nanofiber

The performance of a piecewise-stressed ZnO piezoelectric semiconductor nano?ber is studied with the multi-?eld coupling theory. The ?elds produced by equal and opposite forces as well as sinusoidally distributed forces are examined. Speci?c distributions of potential barriers, wells, and regions with effective polarization charges are found. The results are fundamental for the mechanical tuning on piezoelectric semiconductor devices and piezotronics.

Stochastic Resonance of Single (Independent of Each Other) Protein Motor System with Fluctuating Potential Barrier

A single （independent of each other） protein motor system with fluctuating potential barrier and subject to sine electric field is investigated. We first derive the approximate Langevin equation of this system with fluctuating potential barrier. Then from this approximate Langevin equation, we calculate the signal-to-noise ratio （SNR） in the adiabatic limit. The phenomenon of stochastic resonance is found for this protein motor system with fluctuating potential barrier.

Potential Barrier Behavior of BaTiO3-(Bi0.5Na0.5)TiO3 Positive Temperature Coefficient of Resistivity Ceramic

High-Curie-temperature （Tc） lead-free Y-doped 90 mol%BaTiO3-1O mol%（Bi0.5Na0.5 ） TiO3 ceramic with positive temperature coefficient of resistivity （PTCR） is prepared by the conventional solid state reaction in nitrogen atmosphere. The PTCR ceramic exhibits a room-temperature resistivity （p25） of ~500Ω.cm and a high PTCR effect （maximum resistivity （ρmax）/minimum resistivity （ρmin）） of ~4.5 orders of magnitude. A capacitance- voltage approach is first employed to calculate the potential barrier （ Ф ） of the grain boundary of PTCR ceramic above Tc. It is found that the potential barrier changes from 0.17 to 0.77eV as the temperature increases from 180 to 220℃, which is very close to the predictions of the Heywang-Jonker model, suggesting that the capacitance-voltage method is valid to estimate the potential barrier of PTCR thermistor ceramics.

System of Potential Barriers in Nanostructures

Nanoscale superlattice has been investigated theoretically. It has been shown that the deformation effects on the energy spectrum of nanoscale superlattice by changing the interatomic distances as well as varying the width and height of the potential barrier. The potential deformation has been estimated. It has been shown that for different edges of forbidden bands the deformation potential has different values. It has been also analyzed the dependence of the effective mass on energy. It has been determined that the effective mass crosses periodically the zero mark. It has been concluded that this phenomena contributes to the periodic change of the oscillation frequency de Haas-van Alphen effect.

STM investigations of local potential barrier distribution of the atomic surface of graphite

To modulate the tunneling gap with the lock in amplifier in the scanning tunneling microscopy(STM), information of the tunneling current variation can be obtained. The local potential barrier distribution of graphite surface atoms is got by means of such technology. Compared with STM image under topography observation mode, the local potential barrier image has higher resolution and less influence on the tip and better anti interference capability. Observed results of the graphite are given and discussed in this paper.

Effect of a barrier potential on soliton dynamical characteristics in condensates

By using the multiple-scale method, this paper analytically studies the effect of a barrier potential on the dynamical characteristics of the soliton in Bose Einstein eondensates. It is shown that a stable soliton is exhibited at the top of the barrier potential and the region of the absence of the barrier potential. Meanwhile, it is found that the height of the barrier potential has an important effect on the dark soliton dynamical characteristics in the condensates. With the increase of height of the barrier potential, the amplitude of the dark soliton becomes smaller, its width is narrower, and the soliton propagates more slowly.

Electronic transport for armchair graphene nanoribbons with a potential barrier

This paper studies the electronic transport property through a square potential barrier in armchair-edge graphene nanoribbon （AGNR）. Using the Dirac equation with the continuity condition for wave functions at the interfaces between regions with and without a barrier, we calculate the mode-dependent transmission probability for both semiconducting and metallic AGNRs, respectively. It is shown that, by some numerical examples, the transmission probability is generally an oscillating function of the height and range of the barrier for both types of AGNRs. The main difference between the two types of systems is that the magnitude of oscillation for the semiconducting AGNR is larger than that for the metallic one. This fact implies that the electronic transport property for AGNRs depends sensitively on their widths and edge details due to the Dirac nature of fermions in the system.

Anisotropic Ballistic Transport through a Potential Barrier on Monolayer Phosphorene

We demonstrate theoretically the anisotropic quantum transport of electrons through a single barrier on monolayer phosphorene. Using an effective k .p Hamiltonian, we find that the transmission probability for transport through n-n-n （or n p-n） junction is an oscillating function of the incident angle, the barrier height, as well as the incident energy of electrons. The conductance in such systems depends sensitively on the transport direction due to the anisotropic effective mass. By tuning the Fermi energy and gate voltage, the channels can be transited from opaque to transparent, which provides us with an efficient way to control the transport of monolayer phosphorene-based microstructures.

Digital literacy as a potential barrier to implementation of cardiology tele-visits after COVID-19 pandemic: the INFO-COVID survey

BACKGROUND During the COVID-19 pandemic,the implementation of telemedicine has represented a new potential option for outpatient care.The aim of our study was to evaluate digital literacy among cardiology outpatients.METHODS From March to June 2020,a survey on telehealth among cardiology outpatients was performed.Digital literacy was investigated through six main domains:age;sex;educational level;internet access;availability of internet sources;knowledge and use of teleconference software programs.RESULTS The study included 1067 patients,median age 70 years,41.3%females.The majority of the patients(58.0%)had a secondary school degree,but among patients aged≥75 years old the most represented educational level was primary school or none.Overall,for internet access,there was a splitting between"never"(42.1%)and"every day"(41.0%),while only 2.7%answered"at least 1/month"and 14.2%"at least 1/week".In the total population,the most used devices for internet access were smartphones(59.0%),and WhatsApp represented the most used app(57.3%).Internet users were younger compared to non-internet users(63 vs.78 years old,respectively)and with a higher educational level.Age and educational level were associated with nonuse of internet(age-per 10-year increase odds ratio(OR)=3.07,95%CI:2.54-3.71,secondary school OR=0.18,95%CI:0.12-0.26,university OR=0.05,95%CI:0.02-0.10).CONCLUSIONS Telemedicine represents an appealing option to implement medical practice,and for its development it is important to address the gaps in patients’digital skills,with age and educational level being key factors in this setting.

Controlling the collision between two solitons in the condensates by a double-barrier potential

We present an analytical solution of two solitons of Bose-Einstein condensates trapped in a double-barrier potential by using a multiple-scale method. In the linear case, we find that the stable spots of the soliton formation are at the top of the barrier potential and at the region of barrier potential absence. For weak nonlinearity, it is shown that the height of the barrier potential has an important effect on the dark soliton dynamical properties. Especially, in the case of regarding a double-barrier potential as the output source of the solitons, the collision spots between two dark solitons can be controlled by the height of the barrier potential.

Potential energy surfaces of ozone in the ground state

Equilibrium parameters of ozone, such as equilibrium geometry structure parameters, force constants and dissociation energy are presented by CBS-Q ab initio calculations. The calculated equilibrium geometry structure parameters and energy are in agreement with the corresponding experimental values. The potential energy function of ozone with a C2v symmetry in the ground state is described by the simplified Sorbie-Murrell many-body expansion potential function according to the ozone molecule symmetry. The contour of bond stretching vibration potential of an O3 in the ground state, with a bond angle （θ） fixed, and the contour of O3 potential for O rotating around O1-O （R1）, with O1-O bond length taken as the one at equilibrium, are plotted. Moreover, the potentials are analysed.

Short-ranged potential effects on the recurrence spectra of lithium M=1 atoms in parallel electric and magnetic fields

This paper presents recurrence spectra of highly excited lithium atoms with M = 1 state in parallel electric and magnetic fields at a fixed scaled energy ε = -0.03. Short-ranged potentials including ionic core potential and centrifugal barrier are taken into account. Their effects on the states and photo-absorption spectrum are analysed in detail. This demonstrates that the geometric features of classical orbits are of special importance for modulations of the spectral pattern. Thus the weak polarization as well as the reduction of correlation of electrons induced by short-ranged potentials give rise to the recurrence spectra of lithium M = 1 atoms more compact than that of the M = 0 one, which is in good agreement with the experimental prediction.

Relativistic Treatment of Massive Klein-Gordon Particle by Modified Generalized Hulthen Potential

Approximate bound state solutions of spinless particles with a special case of equal scalar and vector modified generalized Hulthen potential has been obtained under the massive Klein-Gordon equation. The energy eigenvalues and the corresponding wave functions expressed in terms of a Jacobi polynomial are also obtained using the parametric generalization of the Nikiforov-Uvarov （NU） method. Under limiting cases our result are in agreement with the existing literature. Our results could be used to study the interactions and binding energies of the central potential for diatomic molecules in the relativistic framework which have many applications in physics and some others related disciplines.

Influence of barrier thickness on the structural and optical properties of InGaN/GaN multiple quantum wells

The structural and optical properties of InGaN/GaN multiple quantum wells （MQWs） with different barrier thick-nesses are studied by means of high resolution X-ray diffraction （HRXRD）, a cross-sectional transmission electron mi-croscope （TEM）, and temperature-dependent photoluminescence （PL） measurements. HRXRD and cross-sectional TEM measurements show that the interfaces between wells and barriers are abrupt and the entire MQW region has good periodic- ity for all three samples. As the barrier thickness is increased, the temperature of the turning point from blueshift to redshift of the S-shaped temperature-dependent PL peak energy increases monotonously, which indicates that the localization po- tentials due to In-rich clusters is deeper. From the Arrhenius plot of the normalized integrated PL intensity, it is found that there are two kinds of nonradiative recombination processes accounting for the thermal quenching of photoluminescence, and the corresponding activation energy （or the localization potential） increases with the increase of the barrier thickness. The dependence on barrier thickness is attributed to the redistribution of In-rich clusters during the growth of barrier layers, i.e., clusters with lower In contents aggregate into clusters with higher In contents.

Boundary Conditions for Sturm-Liouville Equation with Transition Regions and Barriers or Wells

By means of expansions of rapidly in infinity decreasing functions in delta functions and their derivatives, we derive generalized boundary conditions of the Sturm-Liouville equation for transitions and barriers or wells between two asymptotic potentials for which the solutions are supposed as known. We call such expansions “moment series” because the coefficients are determined by moments of the function. An infinite system of boundary conditions is obtained and it is shown how by truncation it can be reduced to approximations of a different order (explicitly made up to third order). Reflection and refraction problems are considered with such approximations and also discrete bound states possible in nonsymmetric and symmetric potential wells are dealt with. This is applicable for large wavelengths compared with characteristic lengths of potential changes. In Appendices we represent the corresponding foundations of Generalized functions and apply them to barriers and wells and to transition functions. The Sturm-Liouville equation is not only interesting because some important second-order differential equations can be reduced to it but also because it is easier to demonstrates some details of the derivations for this one-dimensional equation than for the full three-dimensional vectorial equations of electrodynamics of media. The article continues a paper that was made long ago.

Boosting the performance of crossed ZnO microwire UV photodetector by mechanical contact homo-interface barrier

One-dimensional(1D)micro/nanowires of wide band gap semiconductors have become one of the most promising blocks of high-performance photodetectors.However,in the axial direction of micro/nanowires,the carriers can transport freely driven by an external electric field,which usually produces large dark current and low detectivity.Here,an UV photodetector built from three cross-intersecting ZnO microwires with double homo-interfaces is demonstrated by the chemical vapor deposition and physical transfer techniques.Compared with the reference device without interface,the dark current of this ZnO double-interface photodetector is significantly reduced by nearly 5 orders of magnitude,while the responsivity decreases slightly,thereby greatly improving the normalized photocurrent-to-dark current ratio.In addition,ZnO double-interface photodetector exhibits a much faster response speed(~0.65 s)than the no-interface device(~95 s).The improved performance is attributed to the potential barriers at the microwire-microwire homo-interfaces,which can regulate the carrier transport.Our findings in this work provide a promising approach for the design and development of high-performance photodetectors.

RCEP背景下中国内地对台湾地区贸易壁垒调查的潜在经济冲击研究

长期以来,台湾地区对中国内地产品采取歧视性进口限制,2023年4月12日,商务部就此启动贸易壁垒调查。基于两岸双边贸易依赖程度,筛选出低—中—高三个强度的中国内地对台贸易反制产品组合,运用全球贸易分析模型(GTAP)设定10个不同的情景,分三步模拟中国内地对台贸易壁垒反制、RCEP效应叠加以及中国台湾当局可能的应对措施等多个情景对两岸经济的影响。研究发现:(1)果蔬产品、水产品、饮料及酒、加工食品、纺织品和钢铁产品可作为中国内地对台贸易反制的可行产品组合;(2)中国内地若采取进口限制的反制措施,将对台湾地区纺织品带来深重打击,就业将下降23.6%;农产品出口贸易亦将受到巨大冲击,水产品和果蔬产品的出口额将分别下降31.4%和47.3%,且绿营县市受到的冲击更大;(3)RCEP的生效将放大反制措施对中国内地的积极影响,消解反制措施对中国内地的负向冲击,台湾地区反之;(4)在对贸易壁垒调查的应对措施上,不论对于中国内地还是台湾地区而言,台湾地区取消对中国内地的进口限制均优于加入CPTPP。因此,两岸贸易互动应逐渐走向规范,在“九二共识”的共同政治基础上努力寻求加入RCEP是台湾地区应对贸易壁垒调查的有效途径,同时台湾地区应充分依托福建新路,积极推进两岸高质量融合。

元坝气田长兴组生物礁高含硫底水气藏稳产中后期精准挖潜关键技术

四川盆地元坝气田长兴组生物礁高含硫底水气藏埋深近7000 m,剩余天然气潜力区普遍具有礁体小、储层薄、非均质性强、气水关系复杂、直井产量低等特点,气藏稳产中后期天然气挖潜面临剩余潜力精准预测难度大,超深水平井安全钻井与气井达产风险高等难题。为此,梳理了元坝气田开展挖潜调整以来在高产富集主控因素分析、礁体与储层连通性评价、隔层与渗流通道精细表征、挖潜对策与配套技术研发等方面取得的进展,形成了适用于气田稳产中后期精准挖潜关键技术。研究结果表明:①高产井大多位于构造高部位、生物礁礁顶储层内,礁体与储层发育状况、隔层与渗流通道发育状况、礁体间储层连通性对未动用储量与剩余气分布及开发潜力评价影响较大;②将储层与隔层渗透率比值K_(r)/K_(l)=60和K_(r)/K_(l)=150作为隔夹层类型划分的阈值,可将该区隔夹层划分为致密型、弱渗透型及高渗透型3种类型,高渗透型隔夹层K_(r)/K_(l)<60,对地层水封隔能力弱;③采用流动单元指数(Ifz)可将储层大致分为4个类型,当渗流通道Ifz<2.47时,渗透能力小,可以视为隔夹层;④评价礁体间的连通性关键取决于礁间是否有储层及礁间储层的渗透率级差,当礁间不发育储层,则连通性取决于礁间储层的启动压力梯度与气井生产压差。结论认为:①以礁体发育规模、隔层与渗流通道发育情况、储层连通性及气水分布作为剩余气潜力评价标准对所有潜力区进行分级,优选部署新井、原井眼侧钻、老井挖潜等动用对策及相应的工艺技术,可实现潜力区储量的效益动用;②精准挖潜关键技术已应用于元坝气田天然气挖潜,已实施的8口调整及挖潜井效果显著,配产超过260×10^(4)m^(3)/d,累计产气量超过30×10^(8)m^(3)。该技术对于同类气藏的高效开发具有重要的指导和借鉴意义。

养血滋阴方联合针刺治疗糖尿病眼底出血临床研究

目的:观察养血滋阴方联合针刺治疗糖尿病眼底出血的临床疗效及对动脉血流、视野的影响。方法:采用随机数字表法将124例糖尿病眼底出血患者分为对照组、观察组各62例。2组均给予常规西药治疗,对照组在常规西药治疗基础上联用针刺治疗,观察组在对照组基础上联用养血滋阴方治疗,2组连续治疗1个月。比较2组治疗前后眼动脉血流指标(舒张期血流速度峰值、收缩期血流速度峰值、阻力指数)、眼底出血面积、黄斑厚度、视野灰度值、血管瘤体积、视网膜电图振荡电位(OPs);比较2组治疗前后最佳矫正视力(BCVA)、视功能相关的生活质量量表(VFQ-25)、中医证候评分;比较2组治疗前后趋化因子样受体1(CMKLR1)、肿瘤坏死因子-α(TNF-α)、血管内皮生长因子(VEGF)、血小板源性生长因子-BB(PDGF-BB)水平,并评估2组临床疗效及不良反应发生情况。结果:观察组总有效率96.77%,高于对照组83.87%(P<0.05)。2组治疗后CMKLR1、TNF-α、VEGF、PDGF-BB水平及眼底出血面积、黄斑厚度、视野灰度值、血管瘤体积、阻力指数、OPs、VFQ-25、中医证候评分均较治疗前降低(P<0.05),观察组治疗后CMKLR1、TNF-α、VEGF、PDGF-BB水平及眼底出血面积、黄斑厚度、视野灰度值、血管瘤体积、阻力指数、OPs、VFQ-25、中医证候评分均低于对照组(P<0.05)。2组治疗后舒张期血流速度峰值、收缩期血流速度峰值、BCVA水平升高(P<0.05),观察组治疗后舒张期血流速度峰值、收缩期血流速度峰值、BCVA水平高于对照组(P<0.05)。结论:养血滋阴方联合针刺治疗糖尿病眼底出血疗效确切,能够抑制机体炎症,保护患者视网膜屏障,改善眼动脉血流、视力,提高生活质量。