Bio-syngas production from biomass catalytic gasification

A promising application for biomass is liquid fuel synthesis, such as methanol or dimethyl ether (DME). Previous studies have studied syngas production from biomass-derived char, oil and gas. This study intends to explore the technology of syngas production from direct biomass gasification, which may be more economically viable. The ratio of H-2/CO is an important factor that affects the performance of this process. In this study, the characteristics of biomass gasification gas, such as H-2/CO and tar yield, as well as its potential for liquid fuel synthesis is explored. A fluidized bed gasifier and a downstream fixed bed are employed as the reactors. Two kinds of catalysts: dolomite and nickel based catalyst are applied, and they are used in the fluidized bed and fixed bed, respectively. The gasifying agent used is an air-steam mixture. The main variables studied are temperature and weight hourly space velocity in the fixed bed reactor. Over the ranges of operating conditions examined, the maximum H-2 content reaches 52.47 vol%, while the ratio of H-2/CO varies between 1.87 and 4.45. The results indicate that an appropriate temperature (750 degrees C for the current study) and more catalyst are favorable for getting a higher H-2/CO ratio. Using a simple first order kinetic model for the overall tar removal reaction, the apparent activation energies and pre-exponential factors are obtained for nickel based catalysts. The results indicate that biomass gasification gas has great potential for liquid fuel synthesis after further processing.

Bleaching kinetics of indoly-benzylfulgimide in PMMA

Indoly-benzlfulgimide belongs to the photochromic fulgide family and follows photochemical first order kinetics. Its bleaching kinetics is investigated at 633 nm and 640 nm by spectroscopy, by the time dependence of transmission and of diffraction from holographically induced gratings. The non-exponential decay law resulting for diffraction experiments with a Gaussian beam profile is calculated and verified experimentally. For a quasi-homogeneous beam profile the time constant determined from diffraction decay is half the one for absorbance decay. The photochemical reaction rate of indoly-benzylfulgimide in PMMA is (3.9 +/- 0.3) cm(2)/J at 650 nm. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photoluminescence of GaInP under high pressure

Photoluminescence of GaInP under hydrostatic pressure is investigated. The Gamma valley of disordered GaInP shifts sublinearly upwards with respect to the top of the valence band with increasing pressure and this sublinearity is caused by the nonlinear relationship between lattice constant and hydrostatic pressure. The Gamma valleys of ordered GaInP rise more slowly than that of the disordered one and the relationship between the band gap and the pressure can not be explained in the same way. Taking into account the interactions between the Gamma valley and the folded L valleys, as well as, the X valleys, the experimental pressure dependences of the band gap of ordered GaInP epilayers are calculated and fitted quite well using first order perturbation theory. The results indicate that simultaneous ordering along [111] and [100] directions can occur in ordered GaInP. (C) 1996 American Institute of Physics.

Analysis of directional emission in square resonator lasers with an output waveguide

Square microcavity laser with an output waveguide is proposed and analyzed by the finite-difference time-domain (FDTD) technique. For a square resonator with refractive index of 3.2, side length of 4 microns, and output waveguide of 0.4-micron width, we have got the quality factors (Q factors) of 6.7×10~2 and 7.3×10~3 for the fundamental and first-order transverse magnetic (TM) mode near the wavelength of 1.5 microns, respectively. The simulated intensity distribution for the first-order TM mode shows that the coupling efficiency in the waveguide reaches 53%. The numerical simulation shows that the first-order transverse modes have fairly high Q factor and high coupling efficiency to the output waveguide. Therefore the square resonator with an output waveguide is a promising candidate to realize single-mode directional emission microcavity lasers.

Crystallographic and magnetic properties of hydride R3Fe29-xTxHy (R=Y, Ce, Nd, Sm, Gd, Tb and Dy; T=V and Cr)

The crystallographic and intrinsic magnetic properties of hydride R3Fe29-xTxHy (R=Y, Ce, Nd, Sm, Gd, Tb, and Dy; T=V and Cr) have been investigated. The lattice constants and the unit cell volume of R3Fe29-xTxHy decrease with increasing R atomic number from Nd to Dy, except for Ce, reflecting the lanthanide contraction. Regular anisotropic expansions, mainly along the a- and b-axis rather than along the c-axis, are observed for all the compounds upon hydrogenation. Hydrogenation leads to an increase in Curie temperature. First-order magnetization processes (FOMP) occur in magnetic fields of around 1.5 T and 4.0 T at 4.2 K for Nd3Fe24.5Cr4.5H5.0 and Tb(3)Fc(27.0)Cr(2.0)H(2.8), and around 1.4 T at room temperature for Gd3Fe28.0Cr1.0H4.2 Abnormal crystallographic and magnetic properties of Ce3Fe29-xTxHy suggest that the Ce ion is non-triply ionized.

Photocatalytic degradation of AZO dyes by supported TiO2+UVin aqueous solution

The photocatalytic degradation performance of photocatalysts TiO2 supported on 13-X, Na-Y, 4A zeolites with different loading content was evaluated using the photocatalytic oxidation of dyes direct fast scarlet 4BS and acid red 3B in aqueous medium. The results showed that the best reaction dosage of TiO2-zeolite catalysts is about 2 g/l and the photocatalytic kinetics follows first order for all supported catalysts. The photocatalytic activity order of the three series catalysts is 13X type >Y type >4A type. The physical state of titanium dioxide on the supports is evaluated by X-ray photoelectron spectra (XPS), powder X-ray diffraction (XRD), BET, and FTIR. (C) 2000 Elsevier Science Ltd. All rights reserved.

An eigenfunction expansion-variational method in prediction of the transverse thermal conductivity of fiber reinforced composites considering interfacial characteristics

An eigenfunction expansion-variational method based on a unit cell is developed to deal with the steady-state heat conduction problem of doubly-periodic fiber reinforced composites with interfacial thermal contact resistance or coating. The numerical results show a rapid convergence of the present method. The present solution provides a unified first-order approximation formula of the effective thermal conductivity for different interfacial characteristics and fiber distributions. A comparison with the present high-order results, available experimental data and micromechanical estimations demonstrates that the first-order approximation formula is a good engineering closed-form formula. An engineering equivalent parameter reflecting the overall influence of the thermal conductivities of the matrix and fibers and the interfacial characteristic on the effective thermal conductivity, is found. The equivalent parameter can greatly simplify the complicated relation of the effective thermal conductivity to the internal structure of a composite. (c) 2010 Elsevier Ltd. All rights reserved.

Estimation of Transverse Thermal Conductivity of Doubly-periodic Fiber Reinforced Composites

For steady-state heat conduction a new variational functional for a unit cell of composites with periodic microstructures is constructed by considering the quasi-periodicity of the temperature field and in the periodicity of the heat flux fields. Then by combining with the eigenfunction expansion of complex potential which satisfies the fiber-matrix interface conditions, an eigenfunction expansion-variational method (EEVM) based on a unit cell is developed. The effective transverse thermal conductivities of doubly-periodic fiber reinforced composites are calculated, and the first-order approximation formula for the square and hexagonal arrays is presented,which is convenient for engineering application. The numerical results show a good convergency of the presented method, even through the fiber volume fraction is relatively high. Comparisons with the existing analytical and experimental results are made to demonstrate the accuracy and validity of the first-order approximation formula for the hexagonal array.

微生物法沥取重金属污泥中铬的研究

本文研究了两种微生物及其组合沥取、回收用微生物法治理电镀铬废水产生的铬污泥中的铬。铬污泥富含C、N、O，含铬量为13%， 经X-光电子能谱分析铬以三价态(氢氧化铬)存在。二种微生物分别从一酸性矿水和酸性污泥中分离筛选得到，经鉴定为硫杆菌属 (Thiobacillus Beijerinek)的两个不同种，一为氧化亚铁硫杆菌(Thiobacillu ferrooxidans, TF), 另一为氧化硫硫杆菌 (Thiobacillus thiooxidans, TT)。研究并比较了不同微生物对污泥中铬的沥取能力，结果表明，TT菌沥取铬效率最高。振荡、动 态淋滤、静置等沥取方式经过研究表明动态淋滤为最佳，室温条件下(15-20℃)，污泥浓度为20g/L时，总铬沥出率达60%时所需时 间：动态淋滤为48.5h，振荡和静置方式分别为91.22，81.6h。研究了不同温度、不同起始PH、不同污泥浓度及非成熟菌液对微生 物沥取能力的影响：(1) 沥取前期，温度对铬的沥出影响较大；微生物沥取反应基本属一级反应；温度与反应速率的关系基本符合 Arrhenius方程，但沥取后期这一特点并不突出。(2) 沥取液最适起始PH为菌液自然PH；PH值的人为改变将使铬的沥出大大降低。 (3) 污泥浓度与铬的沥出呈正相关，但浓度高于30g/L时，铬的沥出量不再增加。(4) 非成熟菌液沥出铬的能力较差，但沥取液中 微生物生长繁殖较为活跃。总结微生物沥取反应最佳沥取条件为：TT成熟菌液、污泥浓度10g/L、温度25-36℃、动态淋滤方式，此 时铬几乎可100%从污泥中沥出。经扫描电镜分析，沥取开始时，微生物紧密吸附于污泥颗粒表面上，表面紧密吸附为微生物发挥功 能提供了基础。微生物沥取污泥中铬的反应机理推测为：硫细菌代谢产硫酸或氧化Fe2+成Fe3+，利用酸，Fe3+ 及自身氧化酶系统 氧化污泥中Cr3+为Cr6+,Cr6+溶出结晶为CrO3。This paper has studied bioleaching and recovery of Chronium(Cr)from electroplating sludge by two consortum of bacteria and their combination, with sludge produced by microbiological process treating electroplating wastewater containing Cr as material. The share of Cr is 13% and its state is Cr (OH)3 in the sludge. One of the bacteria in the paper was isolated from acid sewage sludge and the other was from acid mineral water. The former was tested and determined as Thiobacillus ferroxidans(TF) and the latter was Thiobacillus thiooxidans(TT). Different microorganisms, responsible for the metal leaching activity, have great influence on the efficiency of leaching. The results showed that TT has biggest power. Experiments were conducted to examined effects of three different ways of leaching(Shaking, Down-leaching, Static-leaching). When temperature was in-door's (15-20℃)and concentration of the sludge was 20g/L, the bioleaching time required to reach 60% of Cr solubilization with the above three ways were 91.2, 48.5, 81.6h respectively. Down-leaching was proved to be the most efficient. The influence of different temperature, initial PH, concentration of the sludge and non-mature inoculum had been studied. The results obtained reveal that: (1) The variation of temperature is important during the time from initial to middle of leaching. The reaction of bioleaching belongs to first-order. The relation between the bioleaching rate constant(In k)and temerature can be expressed by Arrhenius function. (2) The fittest initial PH is the nature PH of mature inoculum. Any alteration with it could cause clearly negative effection. (3) The concentration of the sludge can make strong influence on the bioleaching efficiency. But when the concentration is above 30g/L, the increasing of Cr in the solution is little. (4) If non-mature inoculum acts as the bioleachin microorganism, little quantity of Cr would be gained from the sludge. But the micormass in the solution is very active. The results from electron microscope showed that microorganisms adhered to the surface of the sludge and the adherence was the first stage of the bioleaching. Some salts of Cr can be obtained afer the water of the bioleaching solution being evaporated. By analysing the results of experiment with X-Ray spectroscopy, the salt was identified as CrO3. The recovery rate of Cr is 78.4%.

重离子加速器中的软件无线电应用

This paper primarily elaborates automatic gain control design method in software radio receiver. It mainly uses in-phase and quadrature components quadratic sum to subtract the expectation of the output power to get the error statistic of the plus. The error statistic of the plus is smoothed by first order digital filter, and then is used to gain the output signals of controller. Thereby, it can make the system work well in certain dynamic region area of signals. It is designed for the Cooling Storage Ring ...中文文摘：本文主要阐述了软件无线电接收机中的相干AGC设计,主要利用了同相和正交支路的平方和与所期望的信号输出功率值相减,得到增益的误差统计量。该误差统计量经过一阶数字滤波器平滑,然后用于控制器输出信号的增益,从而使系统在一定的信号动态范围内都能工作。该设计主要用于兰州重离子加速器冷却存贮环的主环(CSRm)的重离子束团踢轨(Kicker System)的精确控制。

Energy-level shifts of a stationary hydrogen atom in a static external gravitational field with Schwarzschild geometry

he first order perturbations of the energy levels of a stationary hydrogen atom in a static external gravitational field, with Schwarzschild metric, are investigated. The energy shifts are calculated for the relativistic 1S, 2S, 2P, 3S, 3P, 3D, 4S, 4P, 4D, and 4F levels. The results show that the energy-level shifts of the states with total angular momentum quantum number 1/2 are all zero, and the ratio of absolute energy shifts with total angular momentum quantum number 5/2 is 145. This feature can be used to help us to distinguish the gravitational effect from other effects.

Gravitational corrections to energy-levels of a hydrogen atom

The first-order perturbations of the energy levels of a hydrogen atom in central internal gravitational field are investigated. The internal gravitational field is produced by the mass of the atomic nucleus. The energy shifts are calculated for the relativistic 1S, 2S, 2P, 3S, 3P, 3D, 4S, and 4P levels with Schwarzschild metric. The calculated results show that the gravitational corrections are sensitive to the total angular momentum quantum number.

Emittance estimation by an ion optical element with variable focusing strength and a viewing target

The emittance of an extracted ion beam can be estimated to first order by a series of three linear independent profile measurements. This estimation is restricted to the evaluation of an upper limit of the emittance value for a homogeneous, nonfilamented beam. The beam is assumed to be round, respectively elliptical, without any structure of the intensity distribution, no space charge has been assumed for the drifting beam, and the optics is assumed to be linear. Instead of using three different drift sections, a linear focusing element with three different focusing strengths can be used. Plotting the beam radius as function of focusing strength, three independent solutions can be used to calculate the Twiss parameters alpha, beta, and gamma and furthermore the emittance epsilon. Here we describe the measurements which have been performed with the SECRAL ion source at Institute of Modern Physics Lanzhou.

Kinetic study on the photo-catalytic degradation of pyridine in TiO2 suspension systems

It has been generally agreed that pyridine can be effectively mineralized in aerated TiO2 slurries using near-UV irradiation. The knowledge on the kinetics of the system possesses both practical and theoretical values. The present study, on the base of Langmuir-Hinshewood mechanism, illustrates a pseudo first-order kinetic model of the degradation with the limiting rate constant of 3.004 mg l(-1) min(-1) and equilibrium adsorption constant 2.763 x 10(-2) l mg(-1), respectively. The degradation efficiency in alkali is a little higher than that in acid with a minimum at about pH = 5, which is explained by the formation of acid-pyridine in acidic surrounding together with the amphoteric nature of the TiO2 surface. The promotion of H2O2 on the photo-degradation ties in its supplying proper amount of (OH)-O-. radicals for the inducement stage before surface redox reactions. (C) 2004 Elsevier B.V. All rights reserved.

Multipolar model for collisional quantum interference on rotational energy transfer

A theoretical model of collisional quantum interference (CQI) is developed in a diatom-diatom system based on the first-order Born approximation of time-dependent perturbation theory and the multipolar interaction potential. The transition cross section is obtained. The relations between the differential and integral interference angles are discussed. The key factors on the determination of the differential and integral interference angles are obtained. The changing tendency of the interference angles with the experimental temperatures is obtained.