Modeling the infrared radiance of rough sea surface in the infrared windows: 3-5 μm and 8-12 μm

The general formulations for spectral directional emissivity and spectral bi-directional reflectivity are analyzed by using Fresnel's formula and Snell's law in rough sea surface which is simulated by wave facets, whose slopes are changing according to the isotropic Gaussian distribution with respect to surface wind. Then, shadowing effect is taken into account in both emission and reflection of sea surface. On this basis, the mathematic expression is obtained for spectral radiance of rough sea surface, in which the radiance of rough sea surface is considered as a composition of self-emission, reflection of sky and reflection of sun. Finally, calculations for infrared radiance of rough sea surface in bands of 3-5 μm and 8-12 μm are given to illustrate their significant different, which are caused mostly by the dispersion of sun radiation.     

浅海起伏海面下气泡层对声传播的影响

分析了起伏海面下风浪引起的气泡层对海面反射损失和对声传播的影响.一方面,气泡层会改变原来水中的声速剖面;另一方面,气泡层会对声波产生散射和吸收作用.考虑以上两方面的因素,分析了不同风速下气泡层对海面反射损失和声传播损失的影响,仿真发现,在风速大于10 m/s时,对于2 k Hz以上频率时气泡层对小掠射角下海面反射损失的影响不可忽视.在给定的水声环境中,当声源深度和接收深度都为7 m时,风速为16 m/s的风浪下生成的气泡层,在10 km处对3 k Hz的声传播损失的影响达到8.1 d B.当声源深度和接收深度都为18 m时,风速为16 m/s的风浪下生成的气泡层,在10 km处对3 k Hz的声传播损失的影响达到4 d B.     

计算海面激光反射特性的几何光学方法研究

研究了计算海面激光反射的几何光学方法。首先根据JONSWAP非稳态海谱模型数值模拟出二维随机粗糙海面,再采用几何光学方法对入射激光光束在海面上的反射光进行建模,最后计算出海面激光光斑反射光强的空间分布。编制了相关的计算机程序,分析了在不同入射角度和不同风速下的激光光束反射特性。计算结果表明该方法对研究二维随机粗糙海表面激光反射特性有一定参考价值。     

Thin-film electroluminescent structures on substrates with rough surfaces

It is shown that the use of substrates with inner rough and outer diffusely scattering surfaces in film electroluminescent structures makes it possible to substantially increase the coefficient of radiation extraction (by a factor of 1.3–2.5) and the brightness of luminescence (by a factor of 1.2–3.5) as compared to the structure on a smooth surface, which can be employed to enhance the brightness of individual colors of the luminescence of electroluminescent emitters. The results of the investigations indicate a substantial decrease in the constant of the time of brightness buildup (by a factor of 6–8 for MDSDM structures and by a factor of ∼3.8 for MDSCM structures) and the appearance of two segments of brightness decay for MDSMD structures with different constant decay times in going from the structure on a smooth substrate to the structures built on substrates with an inner rough surface. Unlike this, MDSCM structures have two segments of brightness decay on both a smooth substrate and a rough substrate. Ul’yanovsk State University, 42, L. Tolstoi St., Ul’yanovsk, Russia, 432700. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 5, pp. 787–793, September–October, 1998.     

Surface prereverberation in long-range propagation of explosion-generated signals in underwater sound channe

Experimental data on long-range propagation of explosion-generated signals in a well-developed underwater sound channel are analyzed. In the experiments, the wind speed reached 10–11 m/s and the sea state was Beaufort 4–6. At distances of 80–120 km from the source and at two different reception depths, a prereverberation is observed, that is, the advancing of a part of the bistatic surface reverberation with respect to the direct signal. The conditions for the prereverberation to arise are discussed for different distances from the source. On the basis of data processing, the increase rate of the prereverberation signal, its level relative to the direct signal, and frequency dependence are estimated.     

The Origin of Short-Time Variations in Cosmic-Ray Intensity

It is well known today that a continuous stream of highly ionized plasma is emitted from the Sun’s surface. This plasma is called the solar wind and consists of protons, electrons, and light nuclei. The solar wind pushes the solar magnetic field into interplanetary space to form the interplanetary magnetic field. The interplanetary magnetic field is a dynamical system that depends on the solar cycle and the Sun’s rotation phase. Thus, the Solar System is a natural plasma physics laboratory with an enormous multitude of different effects showing the current state of the system. By recording cosmic-ray fluxes, one can study the behavior of the interplanetary magnetic field and obtain information about processes that occur both on the Sun’s surface and throughout the Solar System. The main short-time variations in cosmic-ray intensity include the 27-day variations and the Forbush decreases. These variations are caused by complex solar plasma structures, which are generated by different processes on the Sun’s surface and propagate through space in a wide range of velocities. Cosmic-ray fluxes recorded with the PAMELA magnetic spectrometer on board the Resurs DK1 satellite in 2006–2016 are used to show some examples of cosmic-ray variations.     

Study of main-lobe direction variations in backscattering of 3-cm radio waves by sea surface due to wind-direction variations

We study the correlation between minute variations of the wind direction near the sea surface and those of the main-lobe direction in the backscattering pattern of 3-cm radio waves. The correlation coefficient between wind-direction variations, which were 10°–20°, and main-lobe direction variations varied from 0.52 for nonfiltered signals to 0.83 after filtering frequencies above 1/60 Hz. The response of the scattering pattern was delayed by no more than 20 sec with respect to wind-direction variations. This result shows that short surface waves have a considerable effect on the anisotropy of radio-wave scattering by the sea surface. It also follows that, along with variations of the magnitude of the wind velocity, temporal variations of the wind direction determine the noise background in cases where not the wind itself but, for example, slicks, internal waves, streams, etc. are the object of observation. Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 42, No. 6, pp. 535–542, June 1999.     

Study of photons reflection on rough surface

The purpose of this paper is to study the probability distribution of photon reflection on rough surface experimentally and theoretically. We showed experimentally that for photon reflection on rough surface, the distribution was characterized by the ratio τ/σ, which was defined as the “correlation roughness” of the reflecting surface. Quantitative experimental results based on single-photon counter are compared to the Monte Carlo simulation results. At last, how the intensity of low light-level can be retrieved from photon counting results using improved models is shown.     

The dynamics of relativistic electron fluxes in the near-Earth space in 2001–2005

This paper presents data on relativistic electron fluxes (1.5–3 MeV) measured at altitudes of 360–500 km onboard the CORONAS-F satellite. The monthly average fluxes of these particles in the Earth’s outer radiation belt are shown to greatly increase from August 2001 to September 2003. The monthly average fluxes of relativistic electrons in the Earth’s outer radiation belt in the period from August 2001 to July 2004 are also found to be strongly correlated with the monthly average velocities of the solar wind and values of the Kp-index, with this correlation breaking down after July 2004. This paper discusses the possible reasons for the discovered patterns.     

An angular cutoff composite model for investigation on electromagnetic scattering from two-dimensional rough sea surfaces

Based on the local configuration angle division to select the corresponding method for electromagnetic scattering calculation from rough sea surface,this paper presents an angular cutoff composite model:when the local scattered angle is in the specular region that is given by an approximately 20 degrees cone around the specular direction,the Kirchhoff approximation is applied to evaluate the specular reflection,which dominates the total scattering in this region;the small perturbation method is employed to handle the diffuse reflection which is predominant as the local scattered angle is situated out of the specular region.Numerical results are compared with those of experimental and theoretical models in several configurations as a function of incident angle,wind speed,wind direction.The comparison of numerical results of other experimental and theoretical models in several configurations shows that the new composite model is robust to give accurate numerical evaluations for the sea surface scattering.     

Choosing optical materials for diagnostics of the solar atmosphere in the wavelength range of 6–60 nm

We present our calculations for the reflection characteristics of multilayer mirrors for a series of wavelengths in the interval of 6–60 nm. Interest in these wavelengths is due to preparations for prolonged studies of the Sun within Russia’s ARCA project. For each structure, we suggested a relationship of material layer thicknesses in the period that ensures the optimum reflection coefficient for high spectral selectivity.     

High-contrast and high-efficiency top-emitting organic light-emitting devices

The reflection properties of top-emitting organic light-emitting devices with different electrodes and organic layers were calculated. The results guided the fabrication of a high-contrast device: Au/copper phthalocyanine (CuPc: 35 nm)/N,N’-bis-(1-naphthyl)-N,N’diphenyl-1,1’ biphenyl-4,4’diamine (NPB: 15 nm)/tris(8-hydroxyquinoline) aluminum (Alq₃: 50 nm)/Sm (35 nm)/Alq₃ (65 nm). The device has a contrast ratio of 8.3:1 at a luminance of 300 cd/m² under 1000 lx ambient light, and a maximum luminance and efficiency of 5000 cd/m² and 4.14 cd/A, respectively. The high contrast is attributed to the moderate reflection of Au at 380–550 nm, low reflection of Sm in the visible range, and high absorption of CuPc at 600–700 nm. PACS 85.60.Jb; 78.20.Ci; 78.40.-q     

Underwater sounds of the Pacific Ocean in the shelf zone of Shikotan Island

Results of underwater sounds measurement in the Shikotan’s shelf zone of the Pacific Ocean at the depth of 130 m in the range of frequencies 1.9–11000 Hz at the wind velocity from 0 to 40 m/s are presented. The statistic non-linear relation between the variations of the underwater sound levels and wind velocities has been revealed. Data on biological, seismic, as well as the sounds of rain and ice of this region are presented.     

Effect of metallic surface microroughness on the probability and spectrum of plasmon excitation by a fast charged particle moving parallel to the surface

The Green’s function of the electric field of plasmons is determined in a semi-infinite medium with an abrupt plasma boundary where nonequilibrium conduction electrons either undergo elastic reflection from the boundary or “stick” to it and give rise to a stationary surface charge. The angular reflection of elastically scattered electrons can be either specular or diffuse. The Green’s function is used to find the singleevent spectrum of energy loss by a fast electron moving parallel to the boundary. The effect of electronboundary scattering parameters on the structure of bulk and surface plasmon resonances is analyzed. The probability of transition radiation of bulk plasmon by an electron moving in vacuum is examined. A new type of surface resonance is found under conditions of perfectly elastic scattering of conduction electrons from the plasma boundary, similar in structure to a tangential surface plasmon.     

Investigation of thin-film electroluminescent structures on rough subsrates

Results of experimental investigations of the volt-brightness characteristics, frequency dependences of brightness, and the directional radiation pattern of electroluminescent MSDM, MSCM, and MSDCM emitters, where M stands for the first transparent and second nontransparent electrodes, S is a semiconductor, D is a thin-film dielectric, and C is a silicone-based composite liquid dielectric with a powdered segnetoelectric filler, developed on conventional “smooth” and rough glass substrates are presented. It is shown that electroluminescent structures on rough surfaces have a brightness approximately two times higher than that of similar structures developed on a “smooth” substrate. Ul’yanovsk State University, 42, L. Tolstoi St., Ul’yanovsk, 432700, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 4, pp. 507–512, July–August, 1997.     

Surface reconstruction of a field electron emitter

The surface and emission images of a metal field’s electron cathode in the form of a tip are simulated. The surface structure is calculated in the thin-shell and broken-bond (local-environment) models for the perfect crystal lattice. The cathode shape and macroscopic electric field are represented by the sphere-on-cone model. The amplification of a local electric field is the adjustable parameter of the model. The method of determination of the emitter tip’s crystal faces based on the analysis of the surface atoms’ environment geometry is proposed. It is shown that it is enough to restrict the consideration of geometric environment by the fifth order of the nearest neighbors for the emitter radius of 100–1000 lattice parameters (31.6–316 nm for the tungsten). The crystallographic model of work function anisotropy in the broken-bond approach is used: the local work function’s value is set in accordance with Miller indices of the face containing this area. The model adequacy is corroborated by the comparison of current-voltage characteristics and emission images with the data of the natural experiment.     

On the phenomenological description of surface absorption of light by metals

Fresnel’s formulas for the coefficients of light reflection from a metal surface are refined to take into account light absorption by conduction electrons during their reflection from the boundary of the metal. The estimates obtained show that the refinement may reveal itself in ellipsometric measurements if their errors do not exceed ∼0.5%.     

Effects of pulsed irradiation by low-energy ions during homoepitaxy of silicon from a molecular beam

The change in the morphology of a Si(111) surface under pulsed irradiation by 145-eV Kr⁺ ions with a pulse duration of 0.5 s during epitaxy of silicon from a molecular beam is studied experimentally by RHEED. It is found that pulsed irradiation by low-energy ions intensifies the specular reflection. This corresponds to a decrease in the roughness of the growing surface. It is shown that the observed effect depends strongly on the degree of filling of the surface atomic layer, the substrate temperature, and the ion current density. Pis’ma Zh. éksp. Teor. Fiz. 64, No. 10, 689–694 (25 November 1996)     

Direct measurement of the spatial distribution of light intensity in a scattering medium

A direct nonperturbative measurement of the spatial distribution of the light intensity in a strongly scattering medium is performed using an optoacoustic method. It is shown that near a surface the intensity can be five times greater than the incident intensity, and the absolute maximum of the intensity is observed at a depth ℓ(1–R)(1–4.0R) determined by the photon transport mean free path ℓ and the effective light reflection coefficient R of the boundary separating the scattering and external media. Pis’ma Zh. éksp. Teor. Fiz. 70, No. 3, 187–191 (10 August 1999)