Dynamics of the crystallized one-component plasma

The dynamics and energy of the crystallized one-component plasma (OCP) is evaluated using the self-consistent-phonon (SCP) theory of lattice dynamics. Melting of the crystal is also examined. The OCP crystal is harmonic for particle rms vibrational amplitudes as large as 25% of the interparticle spacing. This is due to the soft (r^?1) core of the Coulomb potential. Anharmonic effects are, however, entirely responsible for the eventual mechanical instability, identified here with melting, of the crystal at large enough rms amplitudes. This takes place at r_s = 180 at T = 0 K for the most sophisticated SCP theory. In the classical limit, this SCP theory predicts the crystal to be more stable than does the “exact” Monte Carlo study of melting by Pollock and Hansen. This suggests that including further anharmonic terms in the SCP theory leads to melting at even larger r_s at T = 0 K. However, comparison of crystal and fluid energies by Ceperley, Hansen, and Mazighi suggest melting in the range r_s = 65 to 135. Near melting the anharmonic contributions shift the phonon frequencies by a factor of 2 and the phonon lifetimes become very short.     

Effect of intense internal waves on the sound field interference structure

The effect of a train of internal-wave solitons on the formation of space-frequency interference pattern of sound field in an oceanic waveguide has been analyzed. Numerical calculations have been performed for the shallow-water channel parameters corresponding to the conditions of the SWARM’95 natural experiment.     

The magnetic domain structure of partially crystallized amorphous Fe—B alloys by electron microscopy

A detailed electron microscopy study has been made of the crystallization behaviour up to 500°C of some amorphous FeB alloys together with accompanying changes in domain structure. Across the whole composition range investigated, crystallization involves the creation of small grains of bcc α-iron as well as larger spherulites comprised mostly of Fe₃B. Both stages of the crystallization process produce remarkable changes in the domain structure, e.g. the formation of magnetization ripple, which to some extent are composition-dependent. These changes are discussed in some detail and models proposed to explain them.     

The structure of crystallized suspensions of polystyrene spheres

We have determined the crystal structure of an ordered aqueous suspension of polystyrene spheres using Bragg scattering of laser light. At low concentrations a body-centered cubic structure is found. At higher concentrations this is found together with face-centered cubic. We believe that the ordering is due to Coulomb repulsion as in the Wigner crystal.     

Effect of background internal waves on the interference structure of the sound field in a shallow sea

The results of a theoretical analysis of the effect produced by an anisotropic field of background internal waves on the localization of the interference pattern in a shallow sea are presented. The space-time variability of the interference invariant and the smearing of the observation direction of interference fringes are considered in a wide frequency range. The stability of the interference pattern formed by both the superposition of the fields of different mode groups and separate mode groups is analyzed in comparison with the unperturbed waveguide. Numerical calculations are performed for longitudinal and transverse orientations of the acoustic track relative to the propagation direction of internal waves.     

Digital holographic interference microscopy in the study of the 3D morphology and functionality of human blood erythrocytes

A digital holographic interference microscope is used to experimentally study the 3D morphology of human blood erythrocytes. It is demonstrated that, in addition to hematological diseases, the diseases of various genesises and external factors serve as the reasons for the morphological modifications of blood erythrocytes. A 3D model of erythrocyte is proposed to quantitatively estimate the effect of morphological modifications of blood erythrocytes on their functionality with respect to the oxygen transfer. It is demonstrated that the observed morphological modifications of erythrocytes lead to a significant decrease in the blood oxygen capacity and can serve as a reason for hypoxia.     

Effect of internal waves on the intensity and interference structure of the sound field in a shelf zone

Experimental data obtained by studying the effect of internal waves with known space-time parameters on the propagation of a 240-Hz tone signal and on the space-time interference structure of the sound field generated by a noiselike sound source are presented.     

Structure and properties of polybutylene crystallized from the glassy state. II. Electron microscopy

Electron microscope studies of as-ultraquenched and subsequently crystallized isotactic polybutylene (PB) are described in this paper. Cold shadowing of the as-quenched samples reveals no distinct structure larger than 30 Å in the amorphous PB. When rapidly warmed to room temperature PB crystallizes as microcrystals of size ranging from 100 to 250 Å. The size of the microcrystals can be changed only by annealing at temperatures higher than T_α; in PB this resulted in the growth of short lamellae. However, by warming the quenched samples slowly to room temperature, large morphological units were obtained. The effect of several quenchants on the crystallization process of PB is also discussed.     

Application of the aperture synthesis technique in optical interference microscopy

A method of integrated computational processing of series of microscopic images obtained at different angles of object illumination is proposed. Numerical simulation is performed based on the rigorous solution of the vector problem of electromagnetic scattering at various objects. The possibilities of increasing the effective resolving power of microscopes by using this method are studied.     

干涉显微镜中相移误差分析

相移误差是影响干涉显微镜测量表面形貌精度的主要因素之一。介绍了四帧算法、五帧算法、四帧免疫算法、五帧免疫算法的原理和计算公式 ,并对其特点进行了分析比较。利用自行研制的带旋转检偏器的干涉显微测量系统 ,分别用四种算法对Ra=0 35μm和Ra=0 .0 9μm粗糙度样块进行了实测。结果表明 ,五帧算法的重复测量精度优于0 5nm ,五帧免疫算法的重复测量精度优于 0 3nm。同时对在普通干涉显微镜上进一步提高其测量精度做了初步探讨     

Near-field scanning optical microscopy imaging of multimode interference

By use of a near-field scanning optical microscope (NSOM) in collection mode, the intensity distribution along a 2 x 2 multimode interference coupler was directly imaged as a function of wavelength. Although calculations can predict the general trend of wavelength dependence and the approximate positions of multiple images in the coupler, the accuracy is poor because of uncertainties in the waveguide width. We show that direct imaging using a NSOM bypasses calculational uncertainties and proves to be a powerful technique for studying these waveguide devices.     

Piezoelectric properties of polymer-piezoelectric ceramic composites crystallized under the action of an electric-discharge plasma

The crystallization of a polymer-piezoelectric ceramic composite under the action of electric-discharge temperature and plasma is shown to cause strong oxidation of polymer chains, which increases the concentration of charge localization centers or the number of local levels in the quasi-bandgap of the polymer phase in the composite. In turn, this oxidation is accompanied by an increase in the interphase charges during electrothermal polarization, which favor effective polarization of piezophase domains and, hence, an increase in the piezoelectric properties. The degree of oxidation of the polymer phase is found to be controlled by the nature of the electric discharges used for composite crystallization. It is experimentally shown that piezoelectric composites should be crystallized under the action of a microdischarge that does not reach the streamer phase of its development. The optimum crystallization conditions are determined.     

Transfer characteristics of rectangular phase gratings in interference microscopy

In this Letter, the transfer characteristics of rectangular periodic phase objects are studied. It turns out that there are significant differences compared to amplitude objects. The imaging of an amplitude object can be understood as a linear process, whereas phase objects behave nonlinearly. It is shown that under certain conditions the correct shape of a rectangular phase grating can be obtained by an interference microscope as long as the first order diffraction component passes the optical imaging system. This result is in a good agreement with experimental observations and computer simulation results.     

非晶硅薄膜的低温快速晶化及其结构分析

在镀铝的廉价玻璃衬底上高速沉积的非晶硅薄膜在不同的温度下退火10min.退火温度为500℃时,薄膜表面形成了硅铝的混合相,非晶硅薄膜开始呈现了晶化现象 退火温度为550℃时,大部分(约80%)的非晶硅晶化为多晶硅,平均晶粒尺寸为500nm 退火温度为600℃时,几乎所有的非晶硅都转化为多晶硅,其平均晶粒尺寸约为15μm.     

Determination of the internal structure of valons

We determine the internal structure functions of the valons introduced by Hwa and coworkers, using low-p _t data and Regge model constraints. Our calibration reaction is the fragmentation processp→π^? observed in 70 GeV/cK ⁺ p interactions. The fitted valon structure parameters are used to make successful predictions for various other fragmentation processes (p→π⁺ andp→K ⁺). A comparison with experimental data of the DISvW ₂ (x)-values implied by this same fit, indicates that soft processes probe the nucleon typically at aQ ²-value of ～1 GeV². This finding supports the hypothesis that soft hadronic reactions are useful (and often unique) tools to learn about hadron quark structure.     

微分干涉相衬显微镜中偏光棱镜设计

微分干涉相衬显微测量术在生物医学、材料科学等领域中有广泛应用 ,其中偏振分光棱镜设计是关键技术之一。对应用于微分干涉相衬显微系统中的偏振分光棱镜 Nomarski棱镜的主要参数之间的关系进行分析 ,并做了设计计算 ,得出了一些有实用价值的结论 ,使 Nomarski棱镜的设计更简便 ,有利于促进微分干涉相衬显微测量术在我国的推广应用     

Numerical correction of coherence gate in full-field swept-source interference microscopy

A big problem in low-coherence interference microscopy is the degradation of the coherence signal caused by shift of the angular and temporal spectrum gates. It limits the depth of field in confocal optical coherence microscopy and degrades images of sample inner structure in most interference microscopy techniques. To overcome this problem we propose numerical correction of the coherence gate in application to full-field swept-source interference microscopy. The proposed technique allows three-dimensional sample imaging without mechanical movement of the microscope components and is also capable of determining separately the geometrical thickness and the refractive index of the sample layers, when the sample contains a transversal pattern. The applicability of the proposed technique is verified with numerical simulation.     

Modification of the structure of bandpass reflection interference filters

Spectral properties of bandpass reflection interference filters, whose components represent interference transmission cutoff short-and long-wavelength filters, are studied. It is shown that the use of transmission cutoff filters provides a uniform suppression of background outside the transmission band of a bandpass reflection filter. A reflection filter becomes a virtually ideal polarizer for radiation incident on the surfaces inside a filter at angles of 35° and greater.