The effect of the shape of nanorod arrays on the nanocarpet effect

The bundling of densely packed free-standing nanorods/nanotubes in a liquid environment, or the 'nanocarpet effect', has a direct impact on the stability of nanostructures used for chemical and biological sensors. Using glancing angle deposition, we prepared four different structures: vertically aligned, tilted, zigzag, and square spring Si nanorod arrays, and compared their stabilities after water treatment. We found that although the tilted nanorods were bent in the nanorod tilting direction, they did not form nanorod bundles, and this structure was the most stable one. The larger the tilting angle, i.e., the more inclined the nanorod was to the surface, the more stable the structure. We also found that the quasi-vertical nanorod structures, the zigzag and square spring structures, showed improved stabilities compared to vertically aligned nanorods. Furthermore, by properly depositing a capping layer on top of the vertically aligned nanorods, the structure became mechanically very stable while the high porosity nature of the nanorod array was maintained. This work is helpful for designing stable nanostructures used in a liquid environment.     

Corrections of size-of-source effect and distance effect in radiometric measurements of radiance

Many optical instruments used in quality control of the optical radiation emission level of several devices are limited by the so-called size-of-source effect (SSE) as well as the distance effect (DE) when we are dealing with very accurate measurements. Different authors have studied the SSE and DE and have proposed experimental methods that provide corrections for them. We describe a general method based on the partial coherence theory that allows us to describe and calculate the SSE and DE in any radiometric system with circular apertures. We show some experimental results that verify our proposal. Additionally, as a practical example, we present the corresponding DE and SSE correction factors for a particular geometry.     

Study of electrorheological effect

The problem of the effect of an electric field on the shear flow of a suspension of finely dispersed quartz in naphthene with admixtures of a surface-active agent is discussed. The possibility of increasing the apparent viscosity of such rheological systems by four orders of magnitude is shown. Experimental results are given that show that a field creates, besides electroviscosity, viscoelasticity and antithixotropy.     

Ag-TCNQ电双稳薄膜的疲劳和锻炼效应研究

用真空蒸法的方法制备了Ag-TCNQ电双稳薄膜.研究了在不同的电压作用下薄膜的阻抗转变规律.发现了阻抗转变过程中的疲劳和锻炼效应即用连续的高于阈值的窄电压脉冲作用于薄膜后,薄膜阻抗转变弛豫时间缩短;而用低于极限电压的脉冲连续作用于薄膜后,薄膜阻抗转变弛豫时间变长.从阻抗转变的能量效应出发,通过外电场的作用导致分子取向的弹性和塑性形变讨论了薄膜电阻跃迁的机理.     

The effect of crystalline structure on molecular effect in ion-induced electron emission

The results of experimental and theoretical study of the molecular effect in ion-induced electron emission from single crystal and polycrystalline materials are presented. It has been found that the electron emission yield γ₂ under N₂⁺ bombardment of a single crystal shows a dependence on ion incidence angle θ, which is analogous to the anisotropy of the yield γ₁ under N⁺ impact. The ratio R₂(θ)=γ₂/2γ₁<1 exhibits, for single crystals, a drastic angular dependence, which was successfully described on the basis of electron sweeping-out mechanism by conjunction of both the sharp channeling at θ<ψ_L and the shadowing-caused bell-like pattern at θ>ψ_L, the Lindhard angle.     

平面设计中的心理效应与传统文化效应

通过对当代平面设计中心理效应和传统文化效应的分析研究,提出了在平面设计中应注重受众心理-需求的研究,继承和挖掘传统文化的形式与内涵的观点,并在平面设计中进行揉和设计,提高平面设计的艺术亲和力和感染力.     

Geometrical effect in submicrometer channel organic field effect transistors

The electrical behaviors of submicrometer bottom-gate bottom-contact organic field effect transistors (OFETs) with submicrometer channel lengths and channel widths were investigated. Short-channel effects (SCEs) were observed for devices with shorter channel lengths and wider channel widths. The SCEs were effectively suppressed by reducing the channel width to 50 nm. The relationship between the drain current density and the drain voltage normalized by their respective channel lengths revealed that the drain current characteristics of shorter length channels fall into two types: parasitic contact resistances at lower drain voltage and SCEs caused by the space charge limiting current at higher drain voltages. The carrier mobility was also investigated, and found to be enhanced in the narrower channel width.     

约束训练对低温Cu-Al-Mn合金形状记忆性能的影响

利用自制弹簧训练装置对Cu-Al-Mn低温形状记忆合金进行了约束训练，测定了训练前后弹簧低温形变量及马氏体相变点的变化。结果表明：进行适当的约束训练可以有效地提高弹簧的低温形变量，训练次数为30左右达到最好效果。训练对弹簧的马氏体相变点影响不大。     

微晶化及活性元素效应在合金抗高温氧化中的协同作用

总结了目前广为研究的微晶化和活性元素效应在合金高温氧化过程中的作用，并讨论了二者的协同效应。微晶化和活性元素效应均能够降低合金的高温氧化速率，提高氧化膜的黏附性。然而，微晶化中晶粒的长大趋势和促进内氧化发生的缺陷对其实际应用造成不利影响，少量活性元素的添加恰好弥补微晶化的这些缺失；活性元素添加须适量，这点限制了它作为保护性氧化膜形核中心的数量及降低氧化速率的幅度，且使得合金氧化增重较未添加活性元素试样略有增加，微晶化则不存在这样的问题，可以弥补应用活性元素效应的不足之处。本工作旨在加深对微晶化和活性元素协同效应对合金高温氧化性能影响的微观理解，为制备性能更为优异的抗高温氧化合金提供理论和实践基础。     

Theory of the radiometer effect

A study is reported of the origin of the force exerted on a plate by a Knudsen gas.     

Thermodynamics of the mechanico-chemical effect

Phenomenological equations describing the mechanico-chemical effect in the range of operation of nonlinear laws were derived, and the validity of these equations was qualitatively proved by experiment.     

Superconducting proximity effect of NbN

Proximity effect sandwiches with NbN as type II superconductor and copper, silver, or gold as normal conductors were prepared. The transition temperature of the double layers investigated by resistivity measurements decreases with increasing thickness of the normal conductor. A maximal decline of 0.5 K was observed. The results are in qualitative agreement with theoretical expectations.Dedicated to Professor Dr. phil. Eduard Justi on his seventieth birthday.This work was supported by the Deutsche Forschungsgemeinschaft.     

Thermodynamics of the mechanico-chemical effect

Methods of the thermodynamics of irreversible processes are used to derive linear phenomenological equations describing the mechanico-chemical and related effects. The nature of this effect and of the potential debasement during plastic deformation of metals is analyzed.     

An effect of normal stresses

A curvilinear equilibrium shape of a thin stream of elastoviscous liquid is discussed. It is shown that one can estimate the elastic stresses, and consequently the elastic characteristics of the liquid, from the shape of the stream. The role of elastic forces in the stability of liquid filaments is analyzed qualitatively.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 34, No. 3, pp. 514–518, March, 1978.The author thank A. N. Prokunin for help in measuring the viscosity of yhe test solution at low deformation rates.     

Thermoacoustic effect of traveling-standing wave

In order to improve thermoacoustic efficiency, the thermoacoustic devices have been developed from standing wave devices to traveling wave devices. Actually, the acoustic field in practical thermoacoustic devices is neither a pure traveling wave nor a pure standing wave. The thermoacoustic effect is the hybrid effect of traveling wave component and standing wave component. Therefore, the thermoacoustic effect of traveling-standing wave will be study in this paper. Firstly, the thermoacoustic conversion performance of the traveling-standing wave are analyzes qualitatively by combining the thermoacoustic conversion performance of the traveling wave with those of the standing wave. Then, based on the basic thermoacoustic formulas, the influence of the parameters of the acoustic field and the regenerator’s structure on the thermoacoustic conversion is analyzed, and the optimum condition for the thermoacoustic conversion is discussed. The results are consistent with the qualitative analysis. Additionally, our theoretical results also show a good agreement with the experimental data [Biwa et al. Phys Rev E 2004;69(6):066304(6)], which indicates the validity of the analysis in this paper. Furthermore, the analysis in this paper further provides a more intensive understanding of these experimental results. The conclusions obtained in this paper are significant to guide for the design of new thermoacoustic devices.     

The chemostress effect

It is shown that the chemical potential of an adatom interacting with a solid substrate can change significantly when external stresses are applied to the solid. An explicit expression is derived for this chemostress coefficient in terms of experimentally measurable quantities starting with the canonical partition function and using the Jarman rule of polarizability for alkali halides and the Bardeen potential for metals. The analysis indicates the need to perform a number of specific experiments and to develop further the theory of dispersion forces at high pressures applied to the solid substrate. The importance of including this chemostress effect in hydrogen embrittlement of iron and oxidation of metals under high stresses is shown.     

The tribovoltaic effect

Contact electrification (or triboelectrification) (CE) is a universal phenomenon between any two materials or two phases of materials. But a contact between two different materials may results in different output. When a p-type semiconductor sliding on a n-type semiconductor surface, the current flowing between the two electrodes on the top of the p-type and the bottom of the n-type is a direct current. This phenomenon is called tribovoltaic effect discovered in the last few years. The mechanism of the tribovoltaic effect is resulted from the electron-hole pairs generated at the PN junction due to the energy released by the formation of the newly formed chemical bonds at the interface due to mechanical sliding, and the inner field built at the PN junction separates the electrons from the holes, resulting in a DC output. The energy released by forming a chemical bond is called “bindington”, which serves as the exciton for exciting the electron-hole pairs, in analogy to the photovoltaic effect. Here, we first review the recent works on the tribovoltaic effect observed at different interfaces. Then, the mechanism of the tribovoltaic effect is presented. The surface chemical methods for regulating the tribovoltaic effect are discussed. Finally, a technique of hybrid tribovoltaic nanogenerator based on the tribovoltaic effect and its potential applications are elaborated.