Analysis on plasma chemistry and particle growth in corona discharge process for NO/sub x/ removal using discrete-sectional method

The particle formation and growth combined with plasma chemistry in the pulsed corona discharge process (PCDP) to remove NO/sub x/ were analyzed by the discrete-sectional model. In the PCDP, most of the NO is converted into NO/sub 2/ and, later, into HNO/sub 3/ which reacts with NH/sub 3/ to form the NH/sub 4/NO/sub 3/ particle. In the beginning of the reactor, we have the high concentration of small size particles and, later, the particle size distribution in the reactor becomes bimodal with the large size and small size particles and, finally, becomes monodisperse with the large size particles. As the average electron concentration increases, it takes a shorter reactor length to remove the NO/sub x/. As the initial NO and H/sub 2/O concentrations decrease, the NH/sub 3/ is consumed more slowly to form the ammonium nitrates particles. As the averaged electron concentration and initial H/sub 2/O concentration increase, the large size particles grow more quickly and the particle size distribution becomes bimodal earlier. As the initial NO and NH/sub 3/ concentrations increase, the diameter of large size particles becomes larger by the faster coagulation between particles. The predicted NO/sub x/ conversion and particle size distribution were in close agreements with the published experimental results at the averaged electron concentration of 2/spl times/10/sup 5/ cm/sup -3/ in this study.     

The effect of olefinic terminal chains on the mesomorphic properties of 4,4'-disubstituted diphenyldiacetylenes

New diphenyldiacetylenes of the type with A, B = H and/or F; m = 0, 1; n = 1-4; and X = C n H 2n + 1 , F, CF 3 or CN were synthesized and their mesomorphic properties determined by hot stage polarizing microscopy and DSC. When m = 0, all of these compounds showed only a nematic phase except when X = CF 3 when both nematic and smectic A phases were seen. Both clearing and melting temperatures were higher than those reported for substitution with the corresponding alkyl chains but the much larger increase in clearing temperatures produced considerably wider nematic phases. Eutectic mixtures of a few of these olefins yielded nematic materials also having much wider temperature ranges and higher clearing temperatures than the eutectic mixtures of the alkyl compounds, while retaining their high birefringence and low viscosities. Such materials are of interest for beam-steering devices.

Four of the diacetylenes with m = 1 ( A, B = H) were also prepared ( X = C 6 H 13 , F, n = 2, 3). When X was C 6 H 13 ( n = 2), the nematic range was smaller in the 2- than in the 1-olefin but wider than in the alkyl series. When X = F, either no nematic phase or a monotropic one was observed, whereas the 1-olefins gave a much wider nematic phase. Both transition temperatures were lower than those for the corresponding 1-olefin and alkyl analogues. The compound with X = C 6 H 13 and n = 2 had a melting temperature below room temperature.     

Preparation of enantiomerically pure (R)-2-butyryloxymethylglycidol by lipase-catalyzed asymmetric hydrolysis

Optically active epoxy alcohol, (R)-2-butyryloxymethylglycidol3 which is the precursor of a tert-alcohol chiral building block was obtained in high enantiomeric purity, 98.7% e.e., by lipase-catalyzed asymmetric hydrolysis using a phosphate buffer and organic co-solvent system in 95% of chemical yield.     

α－萘甲酰呋喃甲酰甲烷的合成及谱学性质的研究

本文用Ｃｌａｉｓｅｎ缩合反应合成了未见文献报道的一种新的β－二酮，α－萘甲酰呋喃甲酰甲烷（α－ＮＦＭ），考察了该化合物的红外光谱、质谱及核磁共振氢谱。确定其存在着互变异构。     

Separation of screw-sensed particles in a homogeneous shear field

The Stokes motions of three-dimensional screw-sensed slender particles in a homogeneous shear field are investigated, including the effects of buoyancy. Conclusions are drawn about the possibility of achieving a separation of mixtures of right- and left-handed particles. The linearity of the Stokes equations allows complex flows to be solved by adding the effects of the several terms which describe the flow in which the particle is immersed. The homogeneous shear flow considered here consists of three such terms; solutions for a series of 12 unit motions are sufficient to determine the hydrodynamic resistance tensors. The forces and torques experienced by screw-sensed particles are calculated from these 51 resistance tensors, using slender-filament theory. The results allow an estimate of the range of buoyancy parameters for which gravitational sedimentation can be neglected. The fundamental component of the particle motion is a rotation, at approximately the same angular velocity as that of the fluid. Superimposed on this are variations, of large period, in the particle orientation. A phase plane analysis is used to find the terminal orientations. Very long calculation times are required for the phase portrait. An approximate method based on azimuthally-averaged equations is developed to avoid the requirements for long time integration.     

The spectrum is continuous on the set of quasi-n-hyponormal operators

In this paper it is shown that the spectrum σ, a set-valued function, is continuous when the function is restricted to the set of all ‘quasi-n-hyponormal’ operators acting on an infinite-dimensional separable Hilbert space, where a quasi-n-hyponormal operator is defined to be unitarily equivalent to an n×n upper triangular operator matrix whose diagonal entries are hyponormal operators.     

Differential operators on Hilbert modular forms

We investigate differential operators and their compatibility with subgroups of SL₂n(R). In particular, we construct Rankin-Cohen brackets for Hilbert modular forms, and more generally, multilinear differential operators on the space of Hilbert modular forms. As an application, we explicitly determine the Rankin-Cohen bracket of a Hilbert-Eisenstein series and an arbitrary Hilbert modular form. We use this result to compute the Petersson inner product of such a bracket and a Hilbert modular cusp form.     

Dual effects of fullerene doped to holographic polymer dispersed liquid crystals

Doping of conductive fullerene particles to the formulation of conventional holographic polymer dispersed liquid crystal‐induced dual effects of reducing both droplet coalescence and operating voltage. Fullerene induced an induction period which otherwise does not exist, followed by a gradual increase of diffraction efficiency to a saturation value being increased with increasing fullerene content. The increased diffraction efficiency was caused by the decreased droplet coalescence which was due to the hindered migration of LC by the fullerene particles. On the other hand, doped fullerene particles augmented the conductivity of polymer phase and hence the local electrical field imposed on LC droplet, which overcome the threshold for driving and reduced operating voltage and response times. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5590–5596, 2007     

Generalized 3G theorem and application to relativistic stable process on non-smooth open sets

Let G(x,y) and GD(x,y) be the Green functions of rotationally invariant symmetric α-stable process in Rd and in an open set D, respectively, where 0<α<2. The inequality GD(x,y)GD(y,z)/GD(x,z)?c(G(x,y)+G(y,z)) is a very useful tool in studying (local) Schrödinger operators. When the above inequality is true with c=c(D)∈(0,∞), then we say that the 3G theorem holds in D. In this paper, we establish a generalized version of 3G theorem when D is a bounded κ-fat open set, which includes a bounded John domain. The 3G we consider is of the form GD(x,y)GD(z,w)/GD(x,w), where y may be different from z. When y=z, we recover the usual 3G. The 3G form GD(x,y)GD(z,w)/GD(x,w) appears in non-local Schrödinger operator theory. Using our generalized 3G theorem, we give a concrete class of functions belonging to the non-local Kato class, introduced by Chen and Song, on κ-fat open sets. As an application, we discuss relativistic α-stable processes (relativistic Hamiltonian when α=1) in κ-fat open sets. We identify the Martin boundary and the minimal Martin boundary with the Euclidean boundary for relativistic α-stable processes in κ-fat open sets. Furthermore, we show that relative Fatou type theorem is true for relativistic stable processes in κ-fat open sets. The main results of this paper hold for a large class of symmetric Markov processes, as are illustrated in the last section of this paper. We also discuss the generalized 3G theorem for a large class of symmetric stable Lévy processes.     

High power single-frequency continuous-wave Nd:YVO4 master-oscillator power amplifier

We report a highly-efficient, high-power, single-frequency Nd:YVO₄ master-oscillator power-amplifier with near-diffraction-limited output beam quality. A diode-pumped Nd:YVO₄ ring laser incorporating a passive method for suppressing axial-mode-hopping was employed as the master-oscillator, and was amplified by a three-stage diode-end-pumped Nd:YVO₄ amplifier, yielding 79 W of output with an extraction efficiency of 29%. The overall power gain was 15 dB for an input power from the master-oscillator of 2.4 W, and the M² parameter was less than 1.5 at the maximum power. The prospects for a further increase of power and brightness via this approach are considered. PACS 42.55.Xi; 42.60.Da; 42.60.Jf