ANNUAL VARIATIONS OF E-P CROSS SECTION AND TROPOSPHERIC WESTERLY ACCELERATION

This is one part of the series study on the forcing of waves on basic flow, in which theannual variations of E- P cross section are used to compare the wave- mean flow interactionsin the Northern and Southern Hemispheres. Results show that in either hemisphere, wave-meanflow interaction is very strong in winter, and very weak in summer. External forcing sourcefor planetary waves in the Southern Hemisphere appears to be rather weak not only in summer,but also in winter. It is pointed out that in the troposphere. since the mass circulation isstrong, and since the static stability is small, in the dynamic equation, the inertial effect ofthe residual circulation becomes important in balancing that of the E- P flux divergence.Therefore, when the westerly acceleration in the troposphere is studied, both terms of E-Pflux and residual circulation should be considered. It turns out to be more convenient to usethe conventional Euler system to investigate the direct contribution of eddies to the meanflow.     

A THEORY OF BLOCKING FORMATION IN THE ATMOSPHERE

In this paper, a new theory of blocking formation was proposed. The nonlinear Schrdinger equation satisfied by nonlear barotropic Rossby waves for the weak shear zonal flow was obtained by using the WKB method. It was pointed out that when the Rossby wavenumbers sarisfied the relation: k/3相似文献   

Measurement of the thermodynamics of the hydrated dimer and trimer of sulfuric acid

We report measurements of the equilibrium constants, K(p), for the water mediated clustering of two and three sulfuric acid molecules for atmospheric temperatures and relative humidities. Limits for K(p) for the formation of the sulfuric acid tetramer and higher clusters as well as the kinetics of small sulfuric acid cluster growth are also presented. These results put strong constraints on the rate of nucleation in the atmosphere via the H(2)SO(4)/H(2)O neutral mechanism. We show that the neutral nucleation of H(2)SO(4) and H(2)O is slower than ion-induced nucleation of H(2)SO(4) and H(2)O for most conditions found in the middle and upper troposphere. These laboratory-based upper limits to the nucleation rates are also much lower than the predictions of the liquid drop model/classical nucleation theory.     

Nonlinear EHD Stability of the Interfacial Waves of Two Superposed Dielectric Fluids

The slow modulation of the interfacial capillary–gravity waves of two superposed dielectric fluids with uniform depths and solid horizontal boundaries, under the influence of a normal electric field and in the absence of surface charges at their interface, is investigated by using the multiple-time scales method. It is found that the complex amplitude of quasi-monochromatic traveling waves can be described by a nonlinear Schrödinger equation in a frame of reference moving with the group velocity. The stability characteristics of a uniform wave train are examined analytically and numerically on the basis of the nonlinear Schrödinger equation, and some limiting cases are recovered. Three cases appear, depending on whether the depth of the lower fluid is equal to, greater than, or less than the depth of the upper fluid. The effect of the normal electric field is determined for the three stability regions of the pure hydrodynamic case. It is found that the normal electric field has a destabilizing influence in the first stability region and a stabilizing effect in the second and third stability regions. Moreover, one new unstable region or two new stable and unstable regions appear, all of which increase when the electric field increases. On the other hand, the complex amplitude of quasi-monochromatic standing waves near the cutoff wavenumber is governed by a similar type of nonlinear Schrödinger equation in which the roles of time and space are interchanged. This equation makes it possible to estimate the nonlinear effect on the cutoff wavenumber.     

Numerical studies of vertically propagating acoustic and magnetoacoustic waves in an isothermal atmosphere (III)

In this paper we investigate, numerically, the generation and propagation of acoustic and magnetoacoustic waves and their roles in the heating process of the chromosphere. The combined effects of viscosity, thermal conduction and a uniform horizontal magnetic field on an upward and a downward propagating wave in an isothermal atmosphere are considered. It is shown that when the heating mechanisms are dominated by the effects of thermal conduction.

The chromosphere atmosphere can be divided into three distinct regions, low, middle and high. The middle region acts like a semitransparent transition layer and it is produced by thermal conduction and connects middle and high chromosphere. In the transition region part of the energy transmitted upward, part is dissipated and the other part is reflected downward. Moreover, viscosity creates an absorbing and reflecting layer and the magnetic field forms a totally reflecting barrier because of its dissipationless nature. When the combined effects of the viscosity and magnetic field dominated the oscillatory process, thermal conduction can be eliminated because the solution decays exponentially with altitude before the effects of thermal conduction take place.

The formulation of the model leads to a system of differential equations of the velocity and temperature and it will be used for the numerical solutions, and for the analytical solutions we have a fourth order differential equation. The differential equations in both cases are linear but with exponential coefficients. Approximate and exact solutions of the mathematical model are studied, in low, middle, and high chromospheres, both numerically and analytically. The analysis of both studies is in complete agreement with previously observed and reported results and conclusions about the heating process of the chromosphere. The results of the numerical solutions are discussed in connection with the heating mechanisms of the three regions of the chromosphere. Finally, the case where the values of thermal conduction, viscosity and magnetic field are arbitrary is considered.     

Preparation of monocrystalline Pt microelectrodes and electrochemical study of the plane surfaces cut in the direction of the {111} and {110} planes

2-Cyano-1-methylpyridinium ion, I, exhibits three well-defined polarographic waves in Britton-Robinson buffer at pH 5 to 8. Electrolysis at the plateau potential of the most positive wave, involving a one-electron uptake, leads to the formation of a pyridinyl radical which probably dimerizes to a 2,4′-linked structure, VIII. Electrolysis at the plateau potential of the second wave, involving a number of electrons variable between nearly 4 (at pH≈5) and ≈3 (at pH≈8), leads to the formation of a mixture of 2-aminomethyl-1-methylpyridinium ion and 1-methylpyridinium ion. At the third wave potentials the second wave products are further reduced to give basic species with catalytic activity.     

Double-diffusive Cattaneo–Christov squeezing flow of micropolar fluid

Journal of Thermal Analysis and Calorimetry - An incompressible magnetized flow of micropolar fluid is confined between two disks. The lower disk is stationary, while the upper disk moves in upward...     

Electrooxidation of undiluted organic liquids swelling<Emphasis Type="Italic"> N</Emphasis>-isopropylacrylamide-based copolymers

Polyacrylate gels such as: N-isopropylacrylamide (NIPA), ionic copolymer NIPA-co-sodium acrylate (NIPA-co-SA) and ionic copolymer NIPA-co-[2-(acryloyloxy)ethyl]trimethylammonium chloride (NIPA-co-XCl) were swollen by methanol, ethanol and N,N-dimethylformamide. These solvents were oxidized voltammetrically in the gels at platinum microelectrodes. The blocking coefficients, defined as the ratio of the currents observed in the presence and absence of the polymeric chains, were different for the solvents in the charged and uncharged polymers and did not differ for the electroactive probe, ferrocene, present in the solvents at millimolar level. This may mean that the micro ionic layer that is formed at microelectrodes at the plateau of the voltammetric solvent waves leads to a kind of collapse/phase transition of the polymer in the depletion layer. For methanol, the gel structure was found to prevent occasionally the formation of large gas bubbles at the potentials positive versus the first wave and then three one-electron waves could be obtained. Experiments done with a capillary cell and an optical microscope indicated that before formation of large bubbles at the Pt microelectrode a very dynamic, dense stream of microbubbles leaves the electrode surface.Dedicated to Zbigniew Galus on the occasion of his 70th birthday     

Pressure and temperature dependence of methyl nitrate formation in the CH3O2 + NO reaction

The branching ratio β = k(1b)/k(1a) for the formation of methyl nitrate, CH(3)ONO(2), in the gas-phase CH(3)O(2) + NO reaction, CH(3)O(2) + NO → CH(3)O + NO(2) (1a), CH(3)O(2) + NO → CH(3)ONO(2) (1b), has been determined over the pressure and temperature ranges 50-500 Torr and 223-300 K, respectively, using a turbulent flow reactor coupled with a chemical ionization mass spectrometer. At 298 K, the CH(3)ONO(2) yield has been found to increase linearly with pressure from 0.33 ± 0.16% at 50 Torr to 0.80 ± 0.54% at 500 Torr (errors are 2σ). Decrease of temperature from 300 to 220 K leads to an increase of β by a factor of about 3 in the 100-200 Torr range. These data correspond to a value of β ≈ 1.0 ± 0.7% over the pressure and temperature ranges of the whole troposphere. Atmospheric concentrations of CH(3)ONO(2) roughly estimated using results of this work are in reasonable agreement with those observed in polluted environments and significantly higher compared with measurements in upper troposphere and lower stratosphere.     

Barrier scattering with complex-valued quantum trajectories: taxonomy and analysis of isochrones

To facilitate the search for isochrones when using complex-valued trajectory methods for quantum barrier scattering calculations, the structure and shape of isochrones in the complex plane were studied. Isochrone segments were categorized based on their distinguishing features, which are shared by each situation studied: High and low energy wave packets, scattering from both thick and thin Gaussian and Eckart barriers of varying height. The characteristic shape of the isochrone is a trifurcated system: Trajectories that transmit the barrier are launched from the lower branch (T), while the middle and upper branches form the segments for reflected trajectories (F and B). In addition, a model is presented for the curved section of the lower branch (from which transmitted trajectories are launched), and important features of the complex extension of the initial wave packet are identified.     

Reasons of different colors in the ignimbrite lithology: micro-XRF and confocal Raman spectrometry method

Medium to large volume ignimbrites usually show vertical changes in terms of color, mineral components, texture and geochemistry. Determination of vertical changes in single extensive ignimbrite flow unit is difficult and requires careful studies. Color changes in ignimbrite flow units are very important for earth scientists. This may cause to identify the same ignimbrite series with different definition. Incesu ignimbrite has a wide distribution in the Central Anatolian Volcanic Province (CAVP). It is classified into three levels as lower, middle and upper according to color and welding degree. There is a sharp contact between the lower and middle level. The lower level is dark brown to black in color and the middle level has pinkish red to red color. The present paper focuses on the investigation of color changes between the ignimbrite levels by using micro-XRF and confocal Raman spectrometry. Micro-XRF and Raman spectrometry studies were performed on the polished thin sections of the lower and middle levels with different compositions. These differences were because of the compositional changes of K and slightly Fe elements distribution within the matrix. The dark brown to black color of the lower level was related to the high concentration of the K and Fe relatively to the middle level. Confocal Raman spectrometry investigations exhibited the matrix of the lower level mainly composed of anorthoclase, supporting the results of the micro-XRF.     

Temperature dependent absorption cross-sections for acetone and n-butanone—implications for atmospheric lifetimes

Temperature dependent absorption cross-sections for acetone and n-butanone have been measured over the temperature range 260–360 K for 260 nm < λ < 360 nm. The temperature dependence of the cross-sections was fitted using simple, two-level models to allow the measured cross-sections to be extrapolated to upper tropospheric/lower stratospheric temperatures. Atmospheric photoexcitation rates were calculated as a function of altitude using both room temperature and temperature dependent cross-sections. Absorption in the 310–330 nm region makes the dominant contribution to solar photoexcitation in the troposphere and lower stratosphere. Neglect of the temperature dependence of the absorption cross-sections results in significant over-estimations of the solar photoexcitation rate for both acetone and n-butanone in the upper troposphere and lower stratosphere. Since the atmospheric lifetimes of these compounds are inversely proportional to the photoexcitation rate, current models may underestimate the upper atmospheric lifetimes of these compounds by ≈50%.     

Electric field induced instabilities in thin confined bilayers

A long wave nonlinear theory and simulations on the electric field induced instability of a thin (<1000 nm thick) viscous bilayer resting on a solid substrate are presented. The instabilities in these systems are initiated by one of the two basic short time modes of deformation at the twin interfaces-in-phase bending or out of phase squeezing. Linear stability analysis (LSA) is carried out to identify the conditions for these modes. It is shown that these modes can be switched and the relative amplitudes of deformation at the interfaces can be profoundly altered by varying the thicknesses, viscosities, interfacial tensions and dielectric constants of the films. Nonlinear simulations are presented to support the results obtained from the LSA. In addition, simulations show a number of interesting interfacial morphologies including: (a) embedded upper layer in the array of lower layer columns, (b) columns of the upper layer grown towards the substrate and sheathed by the lower layer liquid, (c) lower layer columns sheathed by the upper layer liquid leading to concentric core-shell columns, (d) droplets of upper liquid on the largely undisturbed lower layer, (e) symmetry breaking traveling waves at the interfaces, and (f) evolution of two different wavelengths at the two interfaces of a bilayer. The effects of viscous and the capillary resistances on the evolution of instability and morphology are also discussed.     

Electrochemical Oxidation of Derivatives of Dibenzodiazepin. Dibenzothiazepin and Dibenzoxazepin

Abstract

Clozapin exhibits two anodic waves at ≥ 1 M H₂SO₄, but at lower acidities only the first two-electron wave remains. Cyclic voltammetry shows an ECE mechanism. Reversibility decreases at ≥ 10^?4 M concentrations, due to formation of an adsorptiob film. In nonaqueous solvents two irreversible one-electron waves appear. Clothiapin and loxapin are more difficultly oxidized and can be measured in the presence of clozapin.     

Chemical waves

In our paper we try to describe the basic concepts of chemical waves and spatial pattern formation in a simple way. We pay particular attention to self-organisation phenomena in extended excitable systems. These result in the appearance of travelling waves, spiral waves, target patterns, Turing structures or more complicated structures called scroll waves, which are three-dimensional systems. We describe the most famous oscillating reaction, the Belousov-Zhabotinsky (BZ) reaction, in greater detail. This is because it is of great interest in both physical chemistry and in studies on the evolution and sustenance of self-organising biological systems.     

Mechanism of the OH-initiated oxidation of glycolaldehyde over the temperature range 233-296 K

The mechanism of the gas-phase OH-initiated oxidation of glycolaldehyde (HOCH(2)CHO) was studied in the 233-296 K temperature range using a turbulent flow reactor coupled with a chemical ionization mass spectrometer. In the presence of O2, formaldehyde, CO2, formic acid, and glyoxal were observed at room temperature with the yields of 80, 34, 18, and 14%, respectively. Decrease of temperature to 233 K led to significant changes in the yields of the stable products: those of formaldehyde and glyoxal decreased to 50 and 4%, respectively, whereas that of formic acid increased to 52%. It was also found that the OH + glycolaldehyde + O2 reaction proceeds with considerable reformation of OH radicals (by 25% at 296 K). The observed product yields are explained by a mechanism including formation of short-lived intermediate adducts of the primary radicals with O2. The implication of the obtained results for the HOx budget in the upper troposphere is discussed.     

生物质流化床氧气-水蒸气气化实验研究

在小型流化床气化装置上进行了氧气-水蒸气气化实验,考察了原料、当量比、水蒸气配比、温度、二次风和床料对气化特性的影响。结果表明,原料中C和H含量越高,气化气中H₂和CO含量越高,焦油含量越低;当量比为0.27和水蒸气配比为0.6时,H₂含量达到最大值;温度的升高可提高H₂含量,在840 ℃以上,可提高CO含量;二次风从进料口偏上且二次风比率为15%通入,气体组分变化较明显,二次风通入点位置越高,焦油含量降低幅度越大;白云石和石灰石裂解焦油和提高H₂含量的活性高于橄榄石,但同时明显提高了气体中的灰分含量。     

STATISTICS OF BREAKING WAVES AND ITS APPLICATION TO UPPER OCEAN DYNAMICS

Based on the improved statistics model of breaking waves, we have calculated the following statistical quantities: S_t, breaking area ratio generated per unit time; V_t, the volume of water mass thrown out from the wave surface due to breaking on a unit area per unit time; (?)_t, the breaking energy loss rate on a unit area per unit time. Under the high sea state, the phase change governed by wave breaking is mechanistic. Based on the physical and dimensional consideration we have also derived the statistical quantities of upper ocean dynamics such as whitecap coverage, exchange fluxes in the high sea state and turbulence degree in the subsurface layer. The theoretical results are consistent with the existing experimental data.     

WAVE CHARACTERISTICS OF CRUSTAL TECTONICS IN CONTINENTAL MARGINS

Continental margins are the transitional zone between continents and oceans. The tectonic deformation of crust in continental margins is very complex. This paper deals with the complex crust tectonics of continental margins in terms of the basic principle that elastic waves travel through semi-infinlte medium and the wave theory of crust. The continental margin off the North American coasts of the Atlantic used to be the active Pacifictype margin. At present, the crust movement in this margin tends to be stable; therefore it becomes the Atlantic type.     

溴甲酚紫的极谱研究

溴甲酚紫是一应用广泛的有机式剂^[1-4]。关于羟基三苯甲烷类染料的极谱研究报导不多^[5]。Ghoneim^[6]曾报导溴甲酚紫在pH<7时产生一个2电子还原波,当pH大于10时,可产生两个1电子还原波。Goel^[7]只研究了第一波的还原机理。本文用普通极谱、脉冲极谱、循环伏安等方法较详细地研究了溴甲酚紫的电还原。提出一电还原机理,解释了半波电位随pH变化的特殊规律。