Oscillation properties of eigenfunctions for Sturm-Liouville problems with interface conditions via Prufer transformation

A class of Sturm-Liouville problems with discontinuity is studied in this paper.The oscillation properties of eigenfunctions for Sturm-Liouville problems with interface conditions are obtained.The main method used in this paper is based on Prufer transformation,which is different from the classical ones.Moreover,we give two examples to verify our main results.

Exact solution of plane isolated crack normal to a bimaterial interface of infinite extent

This paper presents an exact solution for the transverse interface crack in the plane strain case. The crack is perpendicular to the interface and in one material. The exact complex stress functions are first obtained with some unknown constants. The satisfactions of all boundary conditions are then checked, the condition at infinity is considered and the unknown constants are determined. Further study may focus on the case with different shear moduli and the influence of the large deformation.

Structure and resistance of concentration polar layer on cation exchange membrane-solution interface

Membrane/solution interface consists of a neutral concentration polar layer(CPL)and a charge layer(CL)under external electrical field,and the neutral CPL can be neglected under high frequency AC electrical field.The relationship of CL thickness e with electrolyte concentration C and fixed ion exchange sites density σ in membrane surface layer can be expressed as e=σ/C.According to this model,the thickness of the CL on Nafion1135 membrane/solution interface(ec)was calculated under different membrane surface charge quantity Q and variable electrolyte concentration C.The membrane/solution interface CL thickness(em)is obviously related with the membrane properties,and decreases dramatically in a higher electrolyte concentration.em values are 76.3 nm and 110.3 nm respectively for Nafion1135 and PE01 ion exchange membrane in 0.05 mol/L H2SO4 solution,and em values for both membrane tend to 2 nm in 2 mol/L H2SO4 solution.For Nafion1135 membrane,the comparison of ec and em gives the result that CL thickness em obtained by resistance measurement fits well with the calculated CPL thickness ec while proton in CL transferred to membrane surface is 14.56×10?10 mol,which corresponds to the fixed exchange group number in a surface layer with a thickness τ=2 nm for Nafion1135 membrane.

Diffusion-controlled Adsorption Kinetics of Surfactant at Air/Solution Interface

For the diffusion-controlled adsorption,the expression of dynamic surface adsorption(t)was obtained by solving the diffusion equation.Two cases,i.e.the short and long time limits,were mainly discussed in this paper.From the measured dynamic surface tension of aqueous surfactant sodium dodecyl sulfate(SDS) solutions at25 °C,the adsorption kinetics of SDS at air/solution interface was studied.It was proved that for both of the short and long time limits,the adsorption process of SDS was controlled by diffusion.

In-situ pH Measurement at the Electrode/Solution Interface

In this paper a pH microprobe technique was developed to measure in-situ the pH value at the electrode/solution interface. Iridium oxide was used as a pH sensitive material with good response behavior in the measured solutions. The experimental results indicated that the interfacial pH increased with the applied potential, first jumped to a maximum, then slowly decreased at the controlled potential during the electrodeposition process of functional ceramics.

IN SITU X-RAY DIFFRACTION CHARACTERIZATION OF SILVER/SOLUTION INTERFACES

In situ x-ray diffraction electrochemical method is used to study the activation of silver electrode in KCl solution and UPD lead on silver electrode surface. We found that the activation makes the silver crystal thicker in (111), and the arrangement of water molecules on the silver electrode surface with UPD lead is partially ordered.

Solution-phase Synthesis of One-dimensional Semiconductor Nanostructures

The synthesis of one-dimensional （1D） semiconductor nanostructures has been studied intensively for a wide range of materials due to their unique structural and physical properties and promising potential for future technological applications. Among various strategies for synthesizing 1D semiconductor nanostructures, solution-phase synthetic routes are advantageous in terms of cost, throughput, modulation of composition, and the potential for large-scale and environmentally benign production. This article gives a concise review on the recent developments in the solution-phase synthesis of ID semiconductor nanostructures of different compositions, sizes, shapes, and architectures. We first introduce several typical solution-phase synthetic routes based on controlled precipitation from homogeneous solutions, including hydrothermal/solvothermal process, solution-liquid-solid （SLS） process, high-temperature organic-solution process, and low-temperature aqueous-solution process. Subsequently, we discuss two solution-phase synthetic strategies involving solid tem- plates or substrates, such as the chemical transformation of 1D sacrificial templates and the oriented growth of 1D nanostructure arrays on solid substrates. Finally, prospects of the solution-phase approaches to 1D semiconductor nanostructures will be briefly discussed.

ON EXISTENCE OF WEAK SOLUTION TO A KIND OF SEMICONDUCTOR EQUATION AFFECTED BY A MAGNETIC FIELD

The semiconductor basic equation system under the influence of magneticfield is considered in this paper.The system is a parabolic-elliptic coupled system with themixed initial-boundary value conditions.The existence result of the weak solution to theproblem is obtained by using the regularizing method and Moser’s technique,and the con-ditions proposed by the authors in another paper are then reduced.

DECAY ESTIMATE OF THE SOLUTIONS TO THE MAGNETO-SEMICONDUCTOR EQUATIONS

In this paper,the relationship between the time-dependent solutions andsteady-state solutions of the semiconductor equations affected by magnetic field isconsidered.A decay estimate between the time-dependent solutions and steady-statesolutions is proved by a series of estimetes on the solutions under some conditions.

INTERFACE MORPHOLOGIES AND SOLUTE SEGREGATION OF Al-Li ALLOY 8090 DURING UNIDIRECTIONAL SOLIDIFICATION

The solid-liquid interface morphology and solute segregation behaviour of AI-Li alloy 8090 during unidirectional solidification were studied by the liquid metal quenehing method under varied processing conditions.When solidification rate,R<O.13 or>O.75 mm/min (temper- ature gradient,G_L=130℃/cm),the structure revealed of planar or dendritic interface respectively.With the increase of R,the interface morphology becomes cellular from planar gradually,within a narrow range.And the greater the R,the,finer the dendrite.Segregation of element Cu and impurity elements Fe and Si are quite severe,the interface morphology markedly influences on solute segregation.During solidification at coarse dendrite interface, their segregation ratios are rather great and solidified structure is coarse.

Asymptotic Behavior of the Solutions to the One-Dimensional Nonisentropic Hydrodynamic Model for Semiconductors

In this paper, the asymptotic behavior of the global smooth solutions to the Cauchy problem for the one-dimensional nonisentropic Euler-Poisson （or full hydrodynamic） model for semiconductors, where the energy equation with non-zero thermal conductivity coefficient are contained, is discussed. The global existence of smooth solutions for the Cauchy problem with small perturbed initial data is proved. In particular, that the solutions converge to the corresponding stationary solutions exponentially fast as t → ∞ is showed.

Asymptotic stability of solutions to the nonisentropic hydrodynamic model for semiconductors

In this paper, the asymptotic stability of smooth solutions to the multidimensional nonisentropic hydrodynamic model for semiconductors is established, under the assumption that the initial data are a small perturbation of the stationary solutions for the thermal equilibrium state, whose proofs mainly depend on the basic energy methods.

Effects of Ca(Y)-Si modifier on interface morphology and solute segregation during directional solidification of an austenite medium Mn steel

The austenite medium Mn steel modified with controlled additions of Ca, Y, Si were directionally solidified using the vertical Bridgman method to study the effects of Ca（Y）-Si modifier on the solid-liquid （S-L） interface morphology and solute segregation. The interface morphology and the C and Mn segregation of the steel directionally solidified at 6.9 μtrn/s were investigated with an image analysis and a scanning electron microscope equipped with energy dispersive X-ray analysis. The 0.5wt% Ca-Si modified steel is solidified with a planar S-L interface. The interface of the 1.0wt% Ca-Si modified steel is similar to that of the 0.5wt% Ca-Si modified steel, but with larger nodes. The 1.5wt% Ca-Si modified steel displays a cellular growth parttern. The S-L interface morphology of the 0.5wt% Ca-Si＋1.0wt% Y-Si modified Mn steel appears as dendritic interface, and primary austenite dendrites reveal developed lateral branching at the quenched liquid. In the meantime, the independent austenite colonies are formed ahead of the S-L interface. A mechanism involving constitutional supercooling explains the S-L interface evolution. It depends mainly on the difference in the contents of Ca, Y, and Si ahead of the S-L interface. The segregation of C and Mn ahead of the S-L interface enhanced by the modifiers is observed.

Compliant semiconductor scaffolds: building blocks for advanced neural interfaces

Neuroscience,neuroprosthetics and neural regeneration would benefit from more adequate interfacing devices.To understand how neurons communicate,process information and control behavior,researchers need to monitor nerve cell activity with high specifity and high spatio-temporal resolution.Neural prostheses require minimally invasive-implantable devices to re- place lost function, and bypass dysfunctional pathways in the nervous system. Devices built to repair damaged nerves have to support and promote regeneration of host neurons through an injured area. Finally, as neuromodulation is being elevated from last resort to first choice treatment for an increasing number of conditions, implantable devices able to perform targeted regu- lation of neural activity are needed. Recent advances in device miniaturization, materials engineering, and nanotechnology are enabling development of an increasing number of devices that effectively interface with neural circuits. Wireless spinal cord and deep brain stimulators, retinal and cochlear implants, high density electrodes arrays for neural recording have already proven to significantly impact fundamental research in neuro- science, as well as individuals＇ quality of life.

Metal-Semiconductor Interfaces Investigated by Positron Annihilation Spectroscopy

Variable-energy positron annihilation spectroscopy has been applied to study interfaces in Al/Si, Au/Si and Au/GaAs structures. Computational fittings of ROYPROF program were used to analyze Doppler broadening results in order to determine kinds of regions that positrons were likely to sample. The interfaces were found acting as a capturing thin layer with negligible positrons stopped in them and their characteristics came only from positrons diffusing to these interfaces, the positron work function of these materials were taken into consideration. In all fittings, the interfaces are found to have 1 nm thickness and act as an absorbing sink for all thermal positrons diffusing towards them, and this indicates either the existence of open volume defects or a weakness of known theoretical models for positron affinities. The result is supported by measurements obtained by applying external electric fields on Al/Si sample. Theoretical fittings have clearly demonstrated the sensitivity of interfaces in these attempts and their importance in data analyzing and in developing of fitting cods.

面向半导体设备的Interface A通信方法研究

针对半导体设备工厂自动化的设备数据采集需求,给出了一种基于Interface A标准的通信方法,该方法构造了设备的通用模型,设计了设备通信的安全认证和授权机制,并给出了采集设备实时数据的方法,可满足工厂自动化系统对半导体设备的数据采集和设备控制需求。

Highly efficient solution-processed organic photovoltaics enabled by improving packing behavior of organic semiconductors

Solution processability is a unique property of organic semiconductors. The compact and regular π-π stacking between molecules is paramount in the performance of organic optoelectronic devices. However, it is still a challenge to improve their stacking quality without sacrificing the solution-processability from the aspect of materials design. Here, delicately engineered additives are presented to promote the formation of ordered aggregation of conjugated molecules by regulating their nucleation and growth dynamics. Intriguingly, the long-chain BTP-eC9-4F molecules can realize ordered aggregation comparable to short-chain ones without sacrificing processability. The domain size of BTP-eC9-4F aggregation is enlarged from 24.2 to 32.2 nm in blend films.Thereby exciton diffusion and charge transport become faster, contributing to the suppression of recombination losses. As a result, a power conversion efficiency of 19.2% is achieved in D18:BTP-eC9-4F based organic photovoltaics. Our findings demonstrate a facile strategy to improve the packing quality of solution-processed organic semiconductors for high-efficiency photovoltaics and beyond photovoltaics.

CALCULATION OF THE DAMPING OF THE Zn-27Al ALLOY BASED ON THE MICRO INTERFACE SLIDING MODEL

The microstructures of the Zn-27Al alloy after modification, solid-solution treatment, and natural aging were studied. It was clarified why the damping properties of Zn-27Al alloys, after treatment, had advanced most on the basis of analyzing the microstructures. Approximate expressions have been educed, which can be used to quantificationally work out the damping of the Zn-27Al alloy on the basis of the micro interface sliding model. By comparing the testing damping properties of the foundry Zn-27Al alloys and the Zn-27Al alloys after modification, solid solution, and natural aging, it was shown that the expressions were rational.

CO_(2)hydrogenation to methanol promoted by Cu and metastable tetragonal Ce_(x)Zr_(y)O_(z) interface

Designing effective catalyst to improve the activity of CO_(2) hydrogenation to methanol is a potential avenue to realize the utilization of CO_(2) resources. Herein we construct three kinds of Cu/Ce_(x)Zr_(y)O_(z)(CCZ) catalysts with different crystal phases of Ce_(x)Zr_(y)O_(z)solid solutions, which demonstrate distinct activity and methanol selectivity in the order of metastable tetragonal-CCZ(CCZ-t’’, parts of oxygen in Ce_(x)Zr_(y)O_(z) were replaced by tetragonal phase from cubic fluorite phase) > tetragonal-CCZ(CCZ-t) > cubic-CCZ(CCZ-c) for CO_(2) hydrogenation to methanol. Structural analysis reveals that oxygen vacancies, surface hydroxyls and unsaturated Cu species of CCZ all follow the same sequence as that of activity and methanol selectivity,indicating that the above features are beneficial to improve the catalytic reaction performance.Temperature programmed experiments and mechanism studies show that the interface between Cu and tetragonal(t and t’’) Ce_(x)Zr_(y)O_(z) can promote CO_(2) adsorption, and the adsorbed CO_(2) is more reactive and can generate active bidentate carbonate species, which can be hydrogenated to form active monodentate and bidentate formate species under CO_(2) and H_(2) atmosphere. These intermediates should be crucial to the formation of methanol product. CCZ-t’’has stronger H_(2) activation ability than CCZ-t, which makes the former catalyst have more intermediates and higher methanol selectivity. In contrast, CO_(2) mainly adsorbs on cubic Ce_(x)Zr_(y)O_(z) support of CCZ-c, but its H_(2) spillover ability is low, which hinders the reaction process. In addition, the strong adsorption of surface intermediates on CCZ-c is also not conducive to methanol formation. Results here demonstrate that constructing active Cu-support interfaces may be an important approach to design effective catalyst for CO_(2)hydrogenation.

Photoluminescence of a ZnO/GaN Heterostructure Interface

Growth of a ZnO/GaN heterostructure is carried out using pulsed laser deposition. By etching the ZnO layer from the ZnO/GaN structure, the photoluminescence （PL） of the associated GaN layer shows that the donor- acceptor luminescence of CaN shifts to about 3.27eV, which is consistent with the electroluminescence （EL） of n-ZnO/p-GaN already reported. XPS shows that oxygen diffuses into the CaN crystal lattice from the surface to 20nm depth. The PL spectra at different temperatures and excitation densities show that oxygen plays the role of potential fluctuation. The associated PL results of the interface in these LEDs could be helpful to understand the mechanism of EL spectra for ZnO/CaN p-n junctions.