On the temperature variations of the integrated absorption intensity in the oxygen fundamental

The goal of this note is to comment on the unusual temperature variations of the integrated absorption intensity measured recently in the region of the oxygen fundamental. More accurate than previous ones and covering wider temperature interval, the observations by Baranov and Lafferty showed that the integrated intensity reaches its minimum at roughly 280 K and then increases steadily at elevated temperature. We suggest that this behaviour can be understood in terms of the flatness of intermolecular potential accompanied by the dominance of the absorption inducing collisions at extremely short distances corresponding to repulsive interaction.     

新型强度检测型表面等离子共振传感器的研究

针对角度检测型表面等离子共振传感器结构复杂,不易于实现在线测量的特点,基于表面等离子共振(SPR)原理,提出了采用双LED进行差分光强检测折射率变化的方法。设计了参考光路,可以消除光源波动带来的影响。理论分析及实验表明,这种方法比单LED光强检测方法的灵敏度提高了近1倍。由于没有使用角度检测装置及光谱仪,易于实现仪器的小型化。     

表面等离子体波传感器角度敏感特性的研究

研究了表面等离子体波共振(SPR)光谱对入射光角度变化的敏感特性,提出了对共振波长和共振强度进行双参数检测的方法。理论分析和实验表明,共振波长和共振强度同时对入射角度的微小改变非常敏感,且相互之间具有良好的对应关系。通过选择合适的棱镜、金属薄膜、调制层等结构参数,能有效地调整角度敏感的范围和灵敏度。     

Diffuse phase transition in a surface quartz layer with variations in temperature

The temperature dependence of the α-phase concentration in surface layers of a solution-grown quartz crystal has been studied in the range 290–820 K. This has been achieved by measuring the intensity of the 695.1, 785.0, and 1061.5 cm^?1 bands in the ?″(ν) IR damping spectra. It has been found that, in a surface layer ～0.15 μm thick, the concentration of the α-phase behaves with increasing temperature as expected for a first-order phase transition, namely, before 800 K, it remains constant, after which at T → 846 K, tends to zero. At a distance from ～1 to 20 μm from the surface, however, the concentration of the α-phase starts to decrease already at ～350 K, while at 812 K it decreases to one-fifth of the original value. This is paralleled by an increase in the intensity of the 804 cm^?1 band assigned to the β-phase. The diffusive pattern of the α-β phase transition is initiated by distortion of the quartz crystal lattice around growth dislocations. The internal stresses arising in these layers have been estimated from the shift of the band maxima. It has been established that at distances up to ～1 μm from the surface, tensile stresses reaching ～300–400 MPa appear at 400 K. These stresses drive in the surface layer of the macrocrystal microcracks culminating in total destruction of the sample. The appearance of tensile stresses is assigned to an increase in volume of the macrocrystal layer located at a distance from ～1 to 20 μm from the surface and the growth in it of the β-phase concentration. At the same time, compressive stresses develop in a layer ～1 to 20 μm thick at a temperature above 500 K, which reach a maximum at ～650 K, to fall off thereafter with increasing temperature. The compression is caused by vibrations of growth dislocation loops in the temperature range specified.     

Spectral features of the water temperature and sound intensity variations measured on the shelf of the Sea of Japan

Results of a spectral analysis of the water temperature and sound intensity variations measured on stationary acoustic-hydrophysical tracks in the shelf zone of the Sea of Japan are presented. The measurements were carried out in different seasons with the use of equipment that included a vertical acoustic-hydrophysical measuring system, self-contained acoustic-hydrophysical radio buoys, and a self-contained electromagnetictype resonance (320 Hz) transmitter. Spectral features of temperature fluctuations caused by internal waves in a vertical water layer are studied, and their influence on the sound propagation is demonstrated on tracks of different lengths oriented along and across the shelf.     

Numerical and experimental investigation of temperature effects on the surface plasmon resonance sensor

The effects of temperature on a surface plasmon studied experimentally and theoretically. SPR resonance （SPR） sensor in Kretschmann configuration are experiments are carried out over a temperature range of 278- 313 K in steps of 5 K. A detailed theoretical model is provided to analyze the variation of performance with varying temperature of the sensing environment. The temperature dependence of the properties of the metal, dielectric, and analyte are studied, respectively. The numerical results indicate that the predictions of the theoretical model are well consistent with the experiment data.     

Experimental comparison between intensity and phase detection sensitivities of grating coupling surface plasmon resonance

This paper experimentally compares the intensity and phase detection sensitivities of grating coupling surface plasmon resonance (SPR). A simple air-heating method is proposed to implement tiny refractive index changes. An electro-optic heterodyne interferometer is used to obtain both the intensity and phase curves of the grating coupling SPR device. The transient reflectivity and phase curves during the heating process are recorded. The result shows that the phase detection sensitivity is much better than that of the intensity by an order of magnitude.     

地面附近的高空核爆电磁脉冲环境

 主要研究在高空核爆的双指数类型电磁脉冲平面波入射时，地面附近的电磁脉冲环境。计算给出了在不同入射波状态，不同地表介质电气特性和距地面不同高度等条件下的电磁脉冲环境参数，归纳了一些规律性认识。结果显示：地面附近的电场会随距地面高度的不同而发生显著的变化，对于水平场分量，其反射场总是试图抵消入射场，而对于垂直场分量，其反射场叠加在入射场上，使得地面附近的垂直场强幅值一般大于入射波场强幅值；当入射波仰角增大时，合成电场波形的脉冲宽度会变宽；地表介质的电气特性参数不同也会对地面附近电场的波形和幅值造成一定的影响。     

Combined effect of light intensity and temperature on the magnetic resonance linewidth in alkali vapor cell with buffer gas

One of the peculiar phenomenons in non-zero magnetic resonance magnetometer is that, with the increase of the temperature, the magnetic resonance linewidth is narrowed at first instead of broadened due to the increasing collision rate. The magnetometer usually operates at the narrowest linewidth temperature to obtain the best sensitivity. Here, we explain this phenomenon quantitatively considering the nonlinear of the optical pumping in the cell and did experiments to verify this explanation. The magnetic resonance linewidth is measured using one amplitude-modulated pump laser and one continuous probe laser. The field is along the direction orthogonal to the plane of pump and probe beams. We change the temperature from 53℃ to 93℃ and the pumping light from 0.1 mW to 2 mW. The experimental results agree well with the theoretical calculations.     

地面附近的高空核爆电磁脉冲环境

主要研究在高空核爆的双指数类型电磁脉冲平面波入射时,地面附近的电磁脉冲环境。计算给出了在不同入射波状态,不同地表介质电气特性和距地面不同高度等条件下的电磁脉冲环境参数,归纳了一些规律性认识。结果显示：地面附近的电场会随距地面高度的不同而发生显著的变化,对于水平场分量,其反射场总是试图抵消入射场,而对于垂直场分量,其反射场叠加在入射场上,使得地面附近的垂直场强幅值一般大于入射波场强幅值;当入射波仰角增大时,合成电场波形的脉冲宽度会变宽;地表介质的电气特性参数不同也会对地面附近电场的波形和幅值造成一定的影响。     

States in temperature and rainfall variations

Summary We report on the existence of three different states (or modes) in air temperature and rainfall variations. Meteorological records dating as far back as 1922 show that both temperature and rainfall variations in a number of East African stations are characterised by systematic switching between two of the three states. This implies that the prediction of droughts and floods may possibly be made on the basis of the latter states and the interstate switching sequences involved. A detailed analysis of the physical processes responsible for these three states is given in a subsequent paper. This short paper highlights new and unique meteorological features whose broader and detailed account is given in a recent ICTP (Trieste, Italia) Internal Report IC/90/396 (1990).     

声强的有旋性与表面声强

本文应用复声强的概念,讨论了复声强的实部即有功声强的有旋性质。指出:在声场中真正传递声能量者仅是有功声强中的无旋分量。所以在应用双传声器声强测量法测量声功率时将受到有旋性的影响。有功声强的无旋分量与表面声强有关,因此测量表面声强可避免有旋性的影响。本文从自功率谱的角度给出了表面声强的有关计算公式,为表面声强测量提供了理论基础。     

Exceptional surface wave as a condition of the maximum increase in the intensity of an evanescent electromagnetic wave in a transparent medium

It has been shown that the condition of the maximum increase in the intensity of TM or TE evanescent electromagnetic waves at the interface between two transparent insulators in a static electric (magnetic) field simultaneously determines the dispersion law of the corresponding exceptional surface wave for which the instantaneous energy flux through the interface is zero at any time.     

Non-perturbative approach to high-index-contrast variations in electromagnetic systems

We present a method that formally calculates exact frequency shifts of an electromagnetic field for arbitrary changes in the refractive index. The possible refractive index changes include both anisotropic changes and boundary shifts. Degenerate eigenmode frequencies pose no problems in the presented method. The approach relies on operator algebra to derive an equation for the frequency shifts, which eventually turn out in a simple and physically sound form. Numerically the equations are well-behaved, easy implementable, and can be solved very fast. Like in perturbation theory a reference system is first considered, which then subsequently is used to solve another related, but different system. For our method precision is only limited by the reference system basis functions and the error induced in frequency is of second order for first-order basis set error. As an example we apply our method to the problem of variations in the air-hole diameter in a photonic crystal fiber.     

Time development of the light intensity in resonance fluorescence

The time evolution of the fluorescent light emitted by a two-level atom that is driven by an external quantum field close to resonance, has been calculated. Although the treatment lies within the framework of QED, it is found that the answer in no way depends on any quantum properties of the field.     

Radon and its short-lived progeny: variations near the ground

In the atmosphere above the surface of the Earth the concentrations of radon and its progeny are measured, along with the meteorological parameters from December 1997 to December 2000 for a continental location, Pune (18°N,74°E), India. The concentrations show maxima in the early morning hours when the turbulence mixing is minimum; whereas in the afternoon the turbulence mixing is maximum and concentrations exhibit minima. The median values of concentration are 9.70 and 2.84 Bqm⁻³, respectively, for radon and its progeny, during the observation period. Ionization rates in the atmosphere are derived for the same period. It is found that the ionization rate exhibits a median value of 5.48 ionpairscm⁻³ s⁻¹. The diurnal and seasonal variations in the concentrations of radon and its progeny, and the ionization rate due to radioactivity are found to exhibit correlation with the relative humidity, and anti-correlation with the temperature.     

The effects of intensity in resonance fluorescence

The probability of resonance fluorescence with account of intensity influence is calculated on the basis of the semiclassical radiation theory. In the case of a monochromatic external field the results confirm those of Mollow. Scattering probabilities in the case of a bichromatic external field are also obtained.     

Absolute intensity of a sodium-like resonance line for temperature diagnosis of neon-like X-ray laser plasmas

Nine different neon-like ions with atomic numbers ranging from 28 to 42 have exhibited gain in various 3p—3s transitions. The temperature of the lasing plasma is critical in determining the state of ionization and the relative importance of collisional excitation and recombination pumping. In this paper we demonstrate a potentially useful new temperature diagnostic for these plasmas that works in the density range of interest for X-ray lasing: the absolute intensity of 3p—3s sodium-like lines. Due to their large collisional couplings and high optical depths, their brightness temperature approaches the actual kinetic temperature of the plasma in temperature and density regimes of importance for achieving optimal X-ray laser performance.     

Correlation of green house molecules with global and surface temperature and its effect on environment

A critical analysis has been made on contribution to green house molecules on global warming and surface air temperature rise. The nature of yearly variations of concentrations of green house molecules and global and surface temperature has been presented. Climate change, environmental and economic effects are briefly mentioned. Various diseases caused by global warming are also discussed.     

Short term intensity variations of cosmic radiation

By means of the dispersion as a function of the length of the registration interval we studied the problem of the variations shorter than an hour. The type of the aforementioned dependence leads us to the conclusion that even in the time of low solar activity the existence of such variations can be proved.Devoted to Professor V. Petrílka on his sixty-fifth birthday.In data processing and calculations appreciable help was offered to us by J. Sláima whom we express our gratitude. We are also indebted to the workers of the computer centre AU CSAV for their effective assistance with our work. We also thank S. Fischer and T. Kowalski for their valuable comments.