NH_3 selective catalytic reduction of NO: A large surface TiO_2 support and its promotion of V_2O_5 dispersion on the prepared catalyst

A titania support with a large surface area was developed, which has a BET surface area of 380.5 m^2/g, four times that of a traditional titania support. The support was ultrasonically impregnated with 5 wt% vanadia. A special heat treatment was used in the calcination to maintain the large surface area and high dispersion of vanadium species. This catalyst was compared to a common V2O5-TiO2 catalyst with the same vanadia loading prepared by a traditional method. The new catalyst has a surface area of 117.7 m^2/g, which was 38% higher than the traditional V2O5-TiO2 catalyst. The selective catalytic reduction（SCR） performance demonstrated that the new catalyst had a wider temperature window and better N2 selectivity compared to the traditional one. The NO conversion was 80% from 200 to 450 °C. The temperature window was 100 °C wider than the traditional catalyst. Raman spectra indicated that the vanadium species formed more V-O-V linkages on the catalyst prepared by the traditional method. The amount of V-O-Ti and V=O was larger for the new catalyst. Temperature programmed desorption of NH3, temperature programmed reduction by H2 and X-ray photoelectron spectroscopy results showed that its redox ability and total acidity were enhanced. The results are helpful for developing a more efficient SCR catalyst for the removal of NOx in flue gases.

WEIGHTED LEAST SQUARE METHOD FOR S-N CURVE FITTING

An S-N curve fitting approach is proposed based on the weighted least square method, and the weights are inversely proportional to the length of mean confidence intervals of experimental data sets. The assumption coincides with the physical characteristics of the fatigue life scatter. Two examples demonstrate the method. It is shown that the method has better accuracy and reasonableness compared with the usual least square method.

Preparation and Characterization of Solid Dispersions of Silymarin with Polyethylene Glycol 6000

Aim To prepare and characterize solid dispersions of silymarin with the intention of improving their dissolution properties. Methods The solid dispersions were prepared by the fusion method with polyethylene glycol 6000(PEG 6000) as the carrier. Evaluation of the properties of the dispersions was performed using dissolution studies, X ray powder diffraction and Fourier transform infrared (FT IR) spectroscopy. Results The rate of dissolution of silymarin was considerably improved as compared with pure silymarin when formulated in solid dispersions with PEG 6000. The data of the X ray diffraction showed some changes in the parameters of lattice spacing [ d ], peak position and relative intensities. FT IR together with those from X ray diffraction showed the absence of well defined drug polymer interactions. Conclusion The dissolution improvement of poorly soluble silymarin could be illuminated by the changes of the lattice parameters of PEG 6000 and the drug.

New Complexiton Solutions of （1＋1）-Dimensional Dispersive Long Wave Equation

By means of two different Riccati equations with different parameters as subequation in the components of finite rational expansion method, new complexiton solutions for the （1＋1）-dimensional dispersive long wave equation are successfully constructed, which include various combination of trigonometric periodic and hyperbolic function solutions, various combination of trigonometric periodic and rational function solutions, and various combination of hyperbolic and rational function solutions.

Supercritical synthesis of platinum-modified titanium dioxide for solar fuel production from carbon dioxide

This paper investigates the properties of TiO2‐based photocatalysts synthesised under supercriticalconditions.Specifically,the characteristics of Pt dispersed on TiO2catalysts obtained in supercriticalCO2are discussed and compared with those of commercial TiO2.The photocatalytic activity of thesynthesised catalysts in the CO2photoreduction reaction to produce solar fuel is tested.The mainconclusion of the study is that photocatalysts with better or similar features,including high surfacearea,crystallisation degree,hydroxyl surface concentration,pore volume,absorbance in the visiblerange and methane production rate,to those of commercial TiO2may be produced for the reductionof CO2to fuel by synthesis in supercritical media.

Viscoelastic properties of monodisperse spherical silica suspension

The viscoelastic properties of the suspension of monodisperse spherical silica produced by hydrolysis of tetraethoxysilane in alcohol solvent with ammonia as a catalyst in polyethylene glycol （PEG） were studied. The results show that the SiO2/PEG suspension possesses the reversible shear thinning and shear thickening behaviors. In the shear thinning region, the loss modulus （G＂） almost remains unchanged, whereas the storage modulus （G＇） decreases. In the shear thickening region, G＂ and G＇ increase for the formation of the ＂clusters＂. The larger G＂ over G＇ in all the stress studied shows that the system mainly possesses the viscous property, and that the energy dissipated（Ed） is larger than that stored. Ed of this suspension is proportional to the maximum strain （Tmax） rising with the exponent of 1.92 under low shear stress; however, in the shear thickening region, Ed is proportional to γ max rising with the exponent of 5.00.

Synthesis of Silica-Dispersed NiMo Hydrodesulfurization Catalysts

Silica-dispersed NiMo hydrodesulfurization catalysts were synthesized by the deposition-precipitation method. For comparative purposes, bulk NiMo catalysts were obtained by co-precipitation. The silica-dispersed NiMo catalyst had highly active metals content. Silica was employed to disperse active metals for full utilization of active components. The BET analysis showed that the silica-dispersed NiMo catalysts had a high surface area （147.0 m2/g） and pore volume （0.27 mL/g）, whereas the bulk NiMo catalysts exhibited a very low surface area （87.5 m2/g）. Transmission electron microscopy results proved that the active components were dispersed on the SiO2 substrate. X-ray diffraction patterns of the silicadispersed NiMo catalyst and the bulk NiMo catalyst were indexed to NiMoO4. The hydrodesulfurization activity of silicadispersed NiMo catalysts was much higher than that of reference catalysts and could be up to twice greater than those of commercial NiMo alumina-supported systems per gram of catalyst. The activity testing results also demonstrated that the silica-dispersed NiMo catalyst was an effective hydrodesulflarization catalyst.

Measurement and Correlation of Solubilities of C.I. Disperse Red 73,C.I. Disperse Blue 183 and Their Mixture in Supercritical Carbon Dioxide

The solubility of disperse dyes and their mixture in supercritical carbon dioxide is an important property in study and development of supercritical fluid dyeing technology.In this study,solubilities of C.I.Disperse Red 73,C.I.Disperse Blue 183 and their mixture in supercritical CO2 are measured at temperatures from 343.2 to 383.2 K and pressures from 12 to 28 MPa with a static recirculation method.Under the experimental conditions for the binary(C.I.Disperse Red 73+CO2 or C.I.Disperse Blue 183+CO2) and ternary(C.I.Disperse Red 73+C.I.Disperse Blue 183+CO2) systems,the solubilities increase with pressure.The solubility of C.I.Disperse Blue 183 decreases with the increase of temperature when the pressure is lower than 16 MPa,and the trend is opposite when the pressure is higher than 16 MPa.However,there is no crossover pressure for C.I.Disperse Red 73.The solubilities are also affected by molecular polarity of dyes.The co-solvent effect exhibited in the dissolving process of mixed dyes promotes their dissolution in supercritical CO2.The experimental data of solubilities of C.I.Disperse Red 73,C.I.Disperse Blue 183,and their mixture are correlated with the Chrastil model and Mendez-Santiago/Teja model. The former is more accurate.

Multi-active region laser diode with a narrow beam divergence angle

A novel large optical cavity laser diode,which consists of multi-active regions cascaded together through tunnel junctions,is proposed.After growing the epi-layers with LP-MOCVD system on GaAs substrate,the ridge waveguide laser structure is fabricated,and it shows a transverse divergence angle as low as 14.4°.

Chemical Enhancement on Surface-Enhanced Resonance Raman Scattering of Au3-1,4-BenzenedithioI-Au3 Junction

Surface-enhanced Raman scattering （SERS） and surface-enhanced resonance Raman scattering （SERRS） spectra of the 1,4-benzenedithiol molecule in the junction of two Au3 clusters have been calculated using density functional theory （DFT） and time-dependent DFT method. In order to investigate the contribution of charge transfer （CT） enhancement, the wavelengths of incident light are chosen to be at resonance with four representative excited states, which correspond to CT in four different forms. Compared with SERS spectrum, SERRS spectra are enhanced enormously with distinct enhancement factors, which can be attributed to CT resonance in different forms.

Modification of nano-TiO_2 by Al_2O_3 in-situ coating

A novel technology of in-situ coating Al2O3 on the surface of H4TiO4 was developed to prevent the aggregation of nano-TiO2 powders and improve the dispersibility and thermal stability in the way of forming a uniform coating layer. The heterogeneous nucleation was conducted to prepare the precursor of nano-TiO2 and then Al2O3 was coated on the surface of precursor. The effects of Al2O3 in-situ coating on the properties of nano-TiO2 were investigated. The results show that H4 TiO4 can be dispersed well under alkaline condition （pH 8. 5） and the heterogeneous nucleation can be controlled easily. The optimized uniform coating layer is obtained by adding 5 % （mass fraction ） and 10% of Al2O3 and the aggregation of nano-TiO2 powders is effectively inhibited and the dispersibility is obviously improved. The crystal sizes of TiO2 powders are 12.3, 11.4 and 8. 7 nm after coating 0, 5% and 10% of Al2O3 respectively. Al2O3 on the surface of particulates in amorphous phase could increase the thermal stability of nano-partieles after calcined at 550℃.

Preparation and in vitro Studies of Stealth PEGylated PLGA Nanoparticles as Carriers for Arsenic Trioxide

The aim of this study was to prepare arsenic trioxide （ATO）-loaded stealth PEGylated PLGA nanoparticles （PEG-PLGA-NPs） and to assess the merits of PEG-PLGA-NPs as drug carriers for ATO delivery. PEG-PLGA copolymer was synthesized with methoxypolyethyleneglycol （Mw=5000）, D, L-lactide, and glycolide by the ring-opening polymerization method. Amorphous ATO was transformed into cubic crystal form to increase its solu-bility in the organic solvent. ATO-loaded PEG-PLGA-NPs were prepared by the modified spontaneous emulsification solvent diffusion （SESD） method, and the main experimental factors influencing the characteristics of nanopar- ticles were investigated, to optimize the preparation. To confirm the escape of PEG-PLGA-NPs from phagocytosis by phagocytes, PEG-PLGA-NPs labeled rhodamine B uptake by murine peritoneal macrophages （MPM） were analyzed by flow cytometry. The results showed that the physicochemical characteristics of PEG-PLGA-NPs were affected by the type and concentration of the emulsifiers, polymer concentration, and drug concentration. ATO-loaded PEG-PLGA-NPs, with particle size of 120.8nm, zeta potential of-10.73mV, encapsulation efficiency of 73.6%, and drug loading of 1.36%, were prepared under optimal conditions. The images of transmission electron micros-copy （TEM） indicated that the optimized nanoparticles were near spherical and without aggregation or adhesion. The release experiments in vitro showed the ATO release from PEG-PLGA-NPs exhibited consequently sustained release for more than 26d, which was in accordance with Higuchi equation. The uptake of PEG-PLGA-NPs by MPM was found to decrease markedly compared to PLGA-NPs. The experimental results showed that PEG-PLGA-NPs were potential nano drug delivery carriers for ATO.

Preparation and characterization of monodisperse zirconia spherical nanometer powder via lamellar liquid crystal template method

Cubic phase spherical zirconia nano-powder was prepared by a direct template route in the lamellar liquid crystal formed by polyoxyethylene tert-octylphenyl ether(Triton X-100)/sodium dodecyl sulfate(SDS)/H_2O.The precursor powder and zirconia powder were characterized by XRD,FT-IR,TG/DSC,TEM,and SEM methods.Results show that the stability of the lamellar liquid crystal is controlled by NH_3·H_2O concentration.The size of nanoparticles is greatly affected by NH_3·H_2O and ZrOCl_2·8H_2O concentrations.The zirconia nanoparticles show narrow particle size distribution of 10-30 nm.

Velocity and Dispersion for a Two-Dimensional Random Walk

In the paper,we consider the transport of a two-dimensional random walk.The velocity and the dispersionof this two-dimensional random walk are derived.It mainly show that:(i)by controlling the values of the transition rates,the direction of the random walk can be reversed;(ii)for some suitably selected transition rates,our two-dimensionalrandom walk can be efficient in comparison with the one-dimensional random walk.Our work is motivated in part by thechallenge to explain the unidirectional transport of motor proteins.When the motor proteins move at the turn pointsof their tracks(i.e.,the cytoskeleton filaments and the DNA molecular tubes),some of our results in this paper can beused to deal with the problem.

Electron Dispersion in Liquid Alkali and Their Alloys

Ashcroft＇s local empty core （EMC） model pseudopotential in the second-order perturbation theory is used to study the electron dispersion relation, the Fermi energy, and deviation in the Fermi energy from free electron value for the liquid alkali metals and their equiatomic binary alloys for the first time. In the present computation, the use of pseudo-alloy-atom model （PAA） is proposed and found successful. The influence of the six different forms of the local field correction functions proposed by Hartree （H）, Vashishta Singwi （VS）, Taylor （T）, lehimaru-Utsumi （IU）, Farid et al. （F）, and Sarkar et al. （S） on the aforesaid electronic properties is examined explicitly, which reflects the varying effects of screening. The depth of the negative hump in the electron dispersion of liquid alkalis decreases in the order Li --→ K, except for Rb and Cs, it increases. The results of alloys are in predictive nature.

Solubility prediction of disperse dyes in supercritical carbon dioxide and ethanol as co-solvent using neural network

Nowadays artificial neural networkS （ANNs） with strong ability have been applied widely for prediction of non- linear phenomenon. In this work an optimized ANN with 7 inputs that consist of temperature, pressure, critical temperature, critical pressure, density, molecular weight and acentric factor has been used for solubility predic- tion of three disperse dyes in supercritical carbon dioxide （SC-C02） and ethanol as co-solvent. It was shown how a multi-layer perceptron network can be trained to represent the solubility of disperse dyes in SC-C02. Numeric Sensitivity Analysis and Garson equation were utilized to find out the degree of effectiveness of different input variables on the efficiency of the proposed model. Results showed that our proposed ANN model has correlation coefficient, Nash-Sutcliffe model efficiency coefficient and discrepancy ratio about 0.998, 0.992, and 1.053 respectively.

Sol-Gel Synthesis and Structure-Property Relations in Silver Nanoparticles-Dispersed in GeO2 Matrix

Synthesis of Ag nanoparticles dispersed in germanium dioxide （GeO2） matrix was performed via sol-gel route. Analysis of the powder X-ray diffraction （XRD） pattern shows fcc cubic unit cell of Ag with lattice parameters： a = 4.0884 A, space group Fm-3m. Energy dispersive analysis of X-rays （EDAX） results show the presence of only GeO2 and Ag in the sample. The average crystallite sizes of Ag particles determined by Scherrer＇s relation are found to be i 8-47 nm. Observed sharp electron paramagnetic resonance （EPR） lineshapes at 8, 70 and 300 K with g-values of 2.004, 2.004, and 2.004, respectively, show that the Ag （5s~） electrons are localized in the Ag nanoparticles. The calculated value of the magnetic susceptibility is 1.014~ 10-5 emu/gG from the observed magnetic moments data at 300 K, which shows fairly strong paramagnetic nature of the material. Refinement of Ag crystal structure in space group Fm-3m with Ag atoms in 4（a） position shows the agreement bond length as 2.8909 ,＆. Calculated density of states below Fermi factors Rp= 67.22%, Rwp= 75.7%, Rexp= 0.06%, Z = 4 and Ag-Ag energy, EF, from -2 to -8 eV are due to valence d orbitals of Ag.

Study on Control Strategy of Sulfur Dioxide Concentration in the Urban Area of Shijiazhuang

Two Gaussian air quality dispersion models, the industrial source complex short-term model (ISCST3) with and without modification have been used to simulate the pollutant concentration distribution in urban areas based on the meteorological data and the emissions distribution of sulfur dioxide. The verified data show that the modified model is more accurate in the urban area of Shijiazhuang. Using the modified model predictions, the control strategies of sulfur dioxide in the urban area have been studied, and the result show that the second long-term (to 2010) strategy can mitigate air pollution significantly and maintain pollution levels within permissible limits.

江苏、上海粮油付产品综合利用情况调查汇报

我们一行三人于三月五日去江苏省和上海市粮食部门基层单位调查了解粮油工业企业扭亏增盈及综合利用情况,历时四十七天,调查了五个地区、四个市、十五个县的四十五个粮油加工厂。兹将粮油付产品综合利用的调查情况汇报如下.