Analysis on the spin reorientation of GdFeCo/DyFeCo exchange-coupled double-layer films

In this paper, GdFeCo/DyFeCo exchange-coupled double-layer films used for center aperture type magnetically induced super resolution were investigated through experiments and theoretical calculation. The samples were prepared by magnetron sputtering method. The polar Kerr effect was measured to prove the spin reorientation of the readout layer. Theoretical study of magnetization profiles was performed on the basis of the mean-field theory and the continuum model. The theoretical results showed that the magnetization orientation of the readout layer changed gradually from in-plane to out-of-plane with the rise of the temperature. Theoretical analysis explained the experimental results successfully. (c) 2005 Elsevier B.V. All rights reserved.

Ag surface plasmon enhanced double-layer antireflection coatings for GaAs solar cells

Surface plasmon enhanced antireflection coatings for GaAs solar cells have been designed theoretically. The reflectance of double-layer antireflection coatings (ARCs) with different suspensions of Ag particles is calculated as a function of the wavelength according to the optical interference matrix and the Mie theory. The mean dielectric concept was adopted in the simulations. A significant reduction of reflectance in the spectral region from 300 to 400 nm was found to be beneficial for the design of ARCs. A new SiO_2/Ag-ZnS double-layer coating with better antireflection ability can be achieved if the particle volume fraction in ZnS is 1%-2%.

Guest inducing p-sulfonatocalix[4] arene into three-dimensional capsule architecture and a mixed A-B double layer framework

The reactions of sodium p-sulfonatocalix[4]arene (Na5L) and terbium/europium(III) chloride in the presence of pyrazine-N,N'-dioxide (PNNO) in aqueous solutions gave the crystalline complexes 1 and 2. Both structures contain molecular capsules of p-sulfonatocalix[4] arene with PNNO as guest molecules in the cavity of the calix[4]arenes. The molecular capsules are connected through sodium and terbium (or europium) centers forming a three-dimensional framework.

Large current gain and low operational voltage permeable metal-base organic transistors based on Au/Al double layer metal base

In order to realize the common-emitter characteristics of the tris(8-hydroxyquinoline) aluminium (Alq(3))-based organic transistors, we used Au/Al double metal layer as the base, thus the vertical metal-base transistors with structure of Al/n-Si/Au/Al/Alq(3)/LiF/Al were constructed. It was found that the contact properties between the base and the organic semiconductors play an important role in the device performance. The utilization of Au/Al double layer metal base allows the devices to operate at high gain in the common-emitter and common-base mode at low operational voltage.

Weak epitaxy growth of metal-free phthalocyanine on p-sexiphenyl monolayer and double-layer films

Weak epitaxy growth (WEG) can afford high-mobility thin films of disk-like organic semiconductor of which mobility is up to the level of the corresponding single crystals. We investigated the WEG behavior and mechanism of planar phthalocyanine in the model system of metal-free phthalocyanine (H2Pc) grown on p-sexiphenyl (p-6P) ultrathin films (monolayers and double layers). Highly oriented H2Pc films with molecules standing up exhibited two kinds of different in-plane orientations, i.e., three sets of in-plane orientations and only one set of in-plane orientation, on p-6P monolayer and double-layer films, respectively.

Double layer capacitance in electrochemical biosensor

The principle and technique of double layer capacitance and its application in electrochemical biosensor are briefly reviewed with 50 references. The future development of double layer capacitance biosensor is expected.

Thermal Properties Measurement of Micro-Electromechanical System Sensors by Digital Moire Method

The thermal properties of a micro-electromechanical system sensor were analysed by a novel digital moire method. A double-layer micro-cantilever sensor (60 mu m long, 10 mu m width and 2 mu dm thick) was prepared by focused ion beam milling. A grating with frequency of 5000 lines mm- I was etched on the cantilever. The sensor was placed into a scanning electron microscope system with a high temperature device. The observation and recording of the thermal deformation of the grating were realised in real-time as the temperature rose from room temperature to 300 degrees C at intervals of 50 degrees C. Digital moire was generated by interference of the deformed grating and a digital virtual grating. The thermal properties including strain distribution of the sensor and the linear expansion coefficient of polysilicon were accurately measured by the phase-shifted moire patterns.

On The Cyclic Bending Behaviour Of A Hard Coating On A Ductile Substrate With Periodic Surface Hardened Regions

A cyclic bending experiment is designed to investigate the interface fracture behaviour of a hard chromium coating on a ductile substrate with periodic surface hardened regions. The unique deflection pattern of the vertical cracks after they run through the coating and impinge at the interface is revealed experimentally. A simple double-layer elastic beam model is adopted to investigate the interfacial shear stresses analytically. A FE model is employed to compute the stresses of the tri-phase structure under a single round of bending, and to investigate the effect of the loading conditions on the deflection pattern of the vertical cracks at the interface. (C) 2008 Elsevier Ltd. All rights reserved.

Solute transport in nanochannels with roughness-like structures

Newfound attention has been given to solute transport in nanochannels. Because the electric double layer (EDL) thickness is comparable to characteristic channel dimensions, nanochannels have been used to separate ionic species with a constant charge-to-size ratio (i.e., electrophoretic mobility) that otherwise cannot be separated in electroosmotic or pressure- driven flow along microchannels. In nanochannels, the electrical fields within the EDL cause transverse ion distributions and thus yield charge-dependent mean ion speeds in the flow. Surface roughness is usually inevitable during microfabrication of microchannels or nanochannels. Surface roughness is usually inevitable during the fabrication of nanochannels. In the present study, we develop a numerical model to investigate the transport of charged solutes in nanochannels with hundreds of roughness-like structures. The model is based on continuum theory that couples Navier-Stokes equations for flows, Poisson-Boltzmann equation for electrical fields, and Nernst-Planck equation for solute transports. Different operating conditions are considered and the solute transport patterns in rough channels are compared with those in smooth channels. Results indicate that solutes move slower in rough nanochannels than in smooth ones for both pressure- driven and electroosmotic flows. Moreover, solute separation can be significantly improved by surface roughness under certain circumstances.

4H-SiC基底Al_2O_3/SiO_2双层减反射膜的设计和制备

在4H-SiC基底上设计并制备了Al2O3/SiO2紫外双层减反射膜,通过扫描电镜(SEM)和实测反射率谱来验证理论设计的正确性。利用编程计算得到Al2O3和SiO2的最优物理膜厚分别为42.0nm和96.1nm以及参考波长λ=280nm处最小反射率为0.09%。由误差分析可知,实际镀膜时保持双层膜厚度之和与理论值一致有利于降低膜系反射率。实验中应当准确控制SiO2折射率并使Al2O3折射率接近1.715。用电子束蒸发法在4H-SiC基底上淀积Al2O3/SiO2双层膜,厚度分别为42nm和96nm。SEM截面图表明淀积的薄膜和基底间具有较强的附着力。实测反射率极小值为0.33%,对应λ=276nm,与理论结果吻合较好。与传统SiO2单层膜相比,Al2O3/SiO2双层膜具有反射率小,波长选择性好等优点,从而论证了其在4H-SiC基紫外光电器件减反射膜上具有较好的应用前景。

Study of the surface plasma transmission properties of a Fabry-Perot resonator by numerical simulation

It is demonstrated with powerful evidence that the extraordinary transmission of a metallic grating is undoubtedly due to the excitation of standing surface plasma waves in the Fabry-Perot like resonator. This is the first time that the strong standing waves set up in the groove of a sub-wavelength double-layer grating (SWDG) for the surface plasma waves have been reported. Moreover, about 90% transmission is gained with an SWDG, more easily fabricated than ordinary metallic gratings, in the first peak of transmission spectrum.

可见光波段双层浮雕型导模共振滤波器设计与分析

基于傅里叶模式理论分析了双层浮雕型导模共振光栅的共振效应,分别讨论了光栅的槽深、剩余厚度、周期以及填充系数对峰值反射率、带宽、旁带反射率的影响.数据计算表明,欠刻蚀情形的误差宽容度远远优于过刻蚀情形,两者在光栅槽深相对误差小于15%的范围内,都能保证共振峰的衍射效率高于99.5%,在相同的误差范围内,共振峰线宽的相对误差将分别达到7%和60%,因此厚度误差集中反映在对共振线宽的改变上.另外,光栅周期和填充系数的变化将明显改变共振峰中心波长和线宽.