Difference of ZSM-5 zeolites synthesized with various templates

ZSM-5 zeolites with similar SUM ratio were synthesized successfully using various templates (n-butylamine (BTA), ethylamine (ETA), isopropylamine (IPA), ethylenediamine (EDA), ethanol (ETL), ethanol-ammonium (ETL-AM) and no template (NT)) under hydrothermal conditions. The samples were characterized by XRD, SEM, XRF, NH3-TPD and BET surface area measurements in order to understand the template effects and the differences of the ZSM-5 samples. The synthesis of ZSM-5 with organic templates was relatively easier than those with inorganic templates and without template. SEM results revealed that ZSM-5 synthesized with different templates had different morphology and particle size. The Si/Al ratio and BET specific surface area of the sample with ethanol as template was the lowest. NH3-TPD results showed that the sample synthesized without template had fewer strong acid sites than others. n-Hexane cracking reaction was carried out over the samples to evaluate the catalytic properties. All ZSM-5 zeolites were effective in n-hexane cracking reaction, especially for the sample synthesized without template. (C) 2004 Elsevier B.V. All rights reserved.

Temperature variation through 2000 years in China: An uncertainty analysis of reconstruction and regional difference

Chinese Academy of Sciences [KZCX2-YW-315, KZCX2-YW-Q1-01]; National Natural Science Foundation of China [40625002, 90502009, 200905006]; Office of Science (BER), U. S. Department of Energy ; EU/FP7 [212250]

Study on the difference of photochromic and thermochromic mechanism of ethylenediamine trimolybdate

Ethylenediamine trimolybdate ((C2H10N2)[Mo3O10], denoted as ENTMo) shows unusual photochromic and thermochromic properties. The color of the white ENTMo compounds becomes reddish brown gradually under UV irradiation, and changes gradually to blue-black upon annealing. XRD patterns and FT-IR spectra verify that the crystal structure of the colored samples is almost unchanged except distortion. UV-vis diffuse reflectance spectra (DRS) and ESR spectra of the photochromic and the thermochromic samples could confirm that there must exist difference between thermochromic and photochromic mechanism.

Digital simulation in a thin layer spectroelectrochemical cell with minigrid platinum electrode by microregion approximation explicit finite difference method

The microregion approximation explicit finite difference method is used to simulate cyclic voltammetry of an electrochemical reversible system in a three-dimensional thin layer cell with minigrid platinum electrode. The simulated CV curve and potential scan-absorbance curve were in very good accordance with the experimental results, which differed from those at a plate electrode. The influences of sweep rate, thickness of the thin layer, and mesh size on the peak current and peak separation were also studied by numerical analysis, which give some instruction for choosing experimental conditions or designing a thin layer cell. The critical ratio (1.33) of the diffusion path inside the mesh hole and across the thin layer was also obtained. If the ratio is greater than 1.33 by means of reducing the thickness of a thin layer, the electrochemical property will be far away from the thin layer property.

The effect of pH difference between two phases on the partition of lysozyme in aqueous two-phase system

In the investigation of effect of KSCN on the partitioning of lysozyme in PEG2000/ammonium sulfate aqueous two-phase system, it was found that the KSCN could alter the pH difference between the two phases. and thus affect the partition of lysozyme. The relationship between partition coefficients of lysozyme and pH differences between two phases was discussed.

Dependence of linear electro-optic coefficient on difference in the atomic sizes in zinc blende crystals

Covalent radii of the bonding elements have strong effects on the linear electro-optic coefficients of zinc blende crystals; these effects can be quantitatively determined by investigating the relation between the difference in the atomic sizes rho and the magnitude of the linear electro-optic tensor coefficient r(41). It is interesting to note that for the same cation Zn2+, Ga3+, or In3+ the magnitude of r(41) increases with increased covalent radius of the bonded anion r(beta). Especially with the increasing tendency of the parameter rho, the magnitude of r(41) of crystals that have a same cation will increase suddenly when the value of r(beta) becomes larger. (C) 1997 Academic Press.

The solution properties of phenolphthalein poly(arylether sulfone) .1. The solubility behavior and determination of M-II equations

A series of narrow molecular weight distribution fractions of phenolphthalein polyarylether sulfone(PES-C) had been prepared, The <(M) over bar (w)> of these fractions were determined by conventional light scattering method. The [eta] and the Huggins slope constant k' in DMF, CHCl3 and 1,2-dichloroethane were also determined. The Huggins constants are greater than 0.5 in all of these solvents showing a special solubility behavior. The Mark-Houwink equations of PES-C in these solvents at 25 degrees C are [eta] = 2.79 x 10(-2) <(M) over bar (0.615)(w)> (DMF); [eta] = 3.96 x 10(-2) <(M) over bar (0.58)(w)> (CHCl3); [eta] = 7.40 x 10(-2) <(M) over bar (0.52)(w)> (CH2ClCH2Cl).

A HYBRID METHOD OF FRACTIONAL STEPS WITH PREDICTOR-CORRECTOR DIFFERENCE-PSEUDOSPECTRUM FOR NUMERICAL-SOLUTION OF THE CONVECTION-DOMINATED FLOW PROBLEMS

A fractional-step method of predictor-corrector difference-pseudospectrum with unconditional L(2)-stability and exponential convergence is presented. The stability and convergence of this method is strictly proved mathematically for a nonlinear convection-dominated flow. The error estimation is given and the superiority of this method is verified by numerical test.

Assessing the potential of VEGETATION sensor data for mapping snow and ice cover: a Normalized Difference Snow and Ice Index

The VEGETATION (VGT) sensor in SPOT 4 has four spectral bands that are equivalent to Landsat Thematic Mapper (TM) bands (blue, red, near-infrared and mid-infrared spectral bands) and provides daily images of the global land surface at a 1-km spatial resolution. We propose a new index for identifying and mapping of snow ice cover, namely the Normalized Difference Snow/Ice Index (NDSII), which uses reflectance values of red and mid-infrared spectral bands of Landsat TM and VGT. For Landsat TM data, NDSII is calculated as NDSIITM =(TM3 -TM5)/(TM3 +TM5); for VGT data, NDSII is calculated as NDSIIVGT =(B2- MIR)/(B2 + MIR). As a case study we used a Landsat TM image that covers the eastern part of the Qilian mountain range in the Qinghai-Xizang (Tibetan) plateau of China. NDSIITM gave similar estimates of the area and spatial distribution of snow/ice cover to the Normalized Difference Snow Index (NDSI=(TM2-TM5)/(TM2+TM5)) which has been proposed by Hall et al. The results indicated that the VGT sensor might have the potential for operational monitoring and mapping of snow/ice cover from regional to global scales, when using NDSIIVGT.

油田高含水期剩余油分布规律研究

After systemic investigation of the techniques，route lines and mechanisms about the remaining oil，the dynamic migration and congregation behavior of the remaining oil are discussed on base of interaction between flowing and enriching of water and oil.After the micro-scope modeling of the fluid flow in porous media and the changes in petrol-physical properties of the flowing system, the characters of fluid fields and the dynamic distribution of oil are discussed, among which the preference-flowing is focused on. Based on the preference-flowing in porous media, the concept of the preference-flowing channels is developed. According to above, heterogeneous distribution of water and oil in the field and dynamic mechanism of remaining oil are all obvious. media can be divided into three kinds, directional, stochastic, arbitrary porous media. The main research results are as following: 1. Treating the characteristic parameters such as permeability, porosity and wettability as regional parameter, the fluid field with high water-cut has been established by geostatistical method, among which the difference of flowing pores and the changes of its petrol-physical properties during flooding are studied. 2. The flow process of water and oil are recurrent in physical simulation experiments, in which the mechanisms and phenomena are caught and analyzed. Fluid flow mechanics in porous media with preference-flowing channels have been studied. 3. The mutual coupling between water and oil is induced and the mathematical evolution equations including this interaction were built. . 4. Through coupling effect between flowing water and oil, the dynamic migration and congregation behavior of remaining oil depend upon this coupling. 5. Coupling between water and oil act as driving force and trapping force for the remaining oil. The coupling model of thesis has been verified by simplified the numerical model and compared results with Ng35 oil reservoir in Gudao oil field, it has important theoretical and application values for improving precision of remaining oil and production performance prediction, and is a new method for studying the mechanics of remaining oil in channeled porous media has been established. Key words：flow field，high water-cut，coupling，dominant flow in porous media，remaining oil

地震波模拟：非规则网格离散的数值解法、吸收边界及其实际应用

This dissertation presents a series of irregular-grid based numerical technique for modeling seismic wave propagation in heterogeneous media. The study involves the generation of the irregular numerical mesh corresponding to the irregular grid scheme, the discretized version of motion equations under the unstructured mesh, and irregular-grid absorbing boundary conditions. The resulting numerical technique has been used in generating the synthetic data sets on the realistic complex geologic models that can examine the migration schemes. The motion equation discretization and modeling are based on Grid Method. The key idea is to use the integral equilibrium principle to replace the operator at each grid in Finite Difference scheme and variational formulation in Finite Element Method. The irregular grids of complex geologic model is generated by the Paving Method, which allow varying grid spacing according to meshing constraints. The grids have great quality at domain boundaries and contain equal quantities of nodes at interfaces, which avoids the interpolation of parameters and variables. The irregular grid absorbing boundary conditions is developed by extending the Perfectly Matched Layer method to the rotated local coordinates. The splitted PML equations of the first-order system is derived by using integral equilibrium principle. The proposed scheme can build PML boundary of arbitrary geometry in the computational domain, avoiding the special treatment at corners in a standard PML method and saving considerable memory and computation cost. The numerical implementation demonstrates the desired qualities of irregular grid based modeling technique. In particular, (1) smaller memory requirements and computational time are needed by changing the grid spacing according to local velocity; (2) Arbitrary surfaces and interface topographies are described accurately, thus removing the artificial reflection resulting from the stair approximation of the curved or dipping interfaces; (3) computational domain is significantly reduced by flexibly building the curved artificial boundaries using the irregular-grid absorbing boundary conditions. The proposed irregular grid approach is apply to reverse time migration as the extrapolation algorithm. It can discretize the smoothed velocity model by irregular grid of variable scale, which contributes to reduce the computation cost. The topography. It can also handle data set of arbitrary topography and no field correction is needed.