Oxidative esterification of acetol with methanol to methyl pyruvate over hydroxyapatite supported gold catalyst: Essential roles of acid-base properties

Acetol is a major light oxygenate and readily produced from staged or fast pyrolysis of lignocellulose biomass. Herein we report that acetol can be selectively converted to methyl pyruvate, an important fine chemical, through oxidative esterification over Au-based catalysts. Detailed experimental studies showed that Au on amphoteric supports with appropriate strength and balanced ratio of acid and base sites can facilitate the desired oxidative-esterification pathway without accelerating undesired aldol-condensation or Cannizzaro reactions. In particular, hydroxyapatite (with a Ca/P ratio of 1.62) supported Au achieved 87% selectivity to methyl pyruvate at an acetol conversion of 62%.

Two Dehydroabietic Acid-based Arylamines: Synthesis, Crystal Structure and Fluorescent Properties

Two dehydroabietic acid-based arylamines have been synthesized and characterized by FTIR, 1H NMR, 13C NMR, MS spectra and elemental analysis. Their spatial structures were determined by X-ray diffraction analysis. UV-Vis absorption and fluorescence spectral characteristics of these compounds in methanol were investigated. Their fluorescence emission spectra in different polarity solvents were further evaluated. Fluorescent properties and structural relationship of the compounds showed that fluorescence intensity and quantum yield inversely increase with the non-coplanar degree. In addition, the solvent polarity has different effects on the fluorescence emission spectra of two compounds.

Cordierite Ceramics Prepared from Poor Quality Kaolin for Electric Heater Supports: Sintering Process, Phase Transformation, Microstructure Evolution and Properties

To efficiently utilize the kaolin, an economical way of preparing cordierite ceramic with high performance for electric heater supports was put forward. In this study, sintering process, phase transformation, microstructure evolutions were systematically studied by heating microscope, X-ray diffraction, scanning electronic microscope and thermal analysis. Properties（physical properties, electrical properties and coefficient of thermal expansion（CTE）） were tested for comprehensive performance evaluation. The results showed that the utilization of poor quality kaolin broadened the firing range of cordierite ceramic which was from 1 200 to 1 380 ℃. Microstructure becomes loose with increasing of the pore size, which had significant influence on bending strength and electrical properties. High content of K2 O in poor quality kaolin was the reason for liquid phase generation in sintering process, which further leads to microstructural changes. The cordierite ceramic sintered at 1 320 ℃ had the properties as follows： CTE of 1.98×10^（-6） ℃^（-1）（500 ℃）, bending strength of 90 MPa, apparent porosity of 15.1%, dielectric constant of 7.5（100 Hz）, and volume resistivity of 1.05×109 Ω·cm（100 Hz）. The comprehensive properties are very suitable for use as electric heater supports.

Acid-base and Electron Donor Properties of Pr_6O_(11)and Its Mixtures with Alumina

The electron donor properties of Pr6O11 activated at 300, 500 and 800℃ are reported from the studies on adsorption of electron acceptors of various electron affinity (7, 7, 8, 8-tetracyanoquinodimethane , 2. 3. 5. 6-tetrachloro-1, 4-benzoquin one, p-dinitrobenzene, and m-dinitrobenzcne) in three solvents (acetonitrile, 1,4-dioxan and ethyl acetate). The extent of electron transfer during adsorption is understood from magnetic measurements and ESR spectral data. The corresponding data on mixed oxides of Pr and Al are reported for various compositions. The acid / base properties of these oxides are determined using a set of Hammett indicators.

Mechanical properties and supporting effect of CRLD bolts under static pull test conditions

A device for supporting soft rock masses combined with a constant resistance structure characterized by constant resistance and large deformation at the end of a steel bar, known as the constant resistance and large deformation（CRLD） bolt, has recently been developed to counteract soft rock swelling that often occurs during deep mining. In order to further study the mechanical properties of the CRLD bolt, we investigated its mechanical properties by comparison with the conventional strength bolt（rebar） using static pull tests on many aspects, including supporting capacity, elongation, radial deformation, and energy absorption. The tests verified that the mechanical defects of the rebar, which include the decrease of bolt diameter, reduction of supporting capacity, and emergence and evolution of fracture until failure during the whole pull process, were caused by the Poisson＇s ratio effect. Due to the special structure set on the CRLD bolt, the bolt presents a seemingly unusual phenomenon of the negative Poisson＇s ratio effect, i.e., the diameter of the constant resistance structure increases while under-pulling. It is the very effect that ensures the extraordinary mechanical properties, including high resistance, large elongation, and strong energy absorption. According to the comparison and analysis of numerical simulation and field test, we can conclude that the CRLD bolt works better than the rebar bolt.

The surface properties of aluminated meso–macroporous silica and its catalytic performance as hydrodesulfurization catalyst support

Aluminated mesoporous silica was prepared by multiple post-grafting of alumina onto uniform mesoporous SiO2 ,which was assembled from monodisperse SiO2 microspheres.Hydrodesulfurization（HDS）catalyst was prepared by loading Ni and Mo active components onto the aluminated uniform mesoporous SiO2 ,and its HDS catalytic performance was evaluated using hydrodesulfurization of dibenzothiophene as the probe reaction at 300℃ and 6.0 MPa in a tubular reactor.The samples were characterized by N2 physisorption,scanning electronic microscopy,Fourier transform infrared spectrum,X-ray diffraction（XRD）,temperature-programmed desorption of ammonia（NH3-TPD）,^27Al nuclear magnetic resonance（^27Al-NMR）and high-resolution transmission electron microscopy（HRTEM）.The results showed that the Si–OH group content of SiO2 was mainly dependent on the pretreatment conditions and had significant influence on the activity of the Ni Mo catalyst.The surface properties of the aluminated SiO2 varied with the Al2O3-grafting cycles.Generally after four cycles of grafting,the aluminated SiO2 behaved like amorphous alumina.In addition,plotting of activity of Ni Mo catalysts supported on aluminated meso–macroporous silica materials against the Al2O3-grafting cycle yields a volcano curve.

Preparation and Properties of Doped Lanthanum Gallate Film on a Ni/SDC Porous Anode Support

A 65. 8-μm dense doped lanthanum gallate La0.8Sr0.2 Ga0.85 Mg0.15 O2.825（LSGM）film was prepared on a porous Ni/SDC（samarium doped ceria, Ce0.8Sm0.2O1.9 ） anode support by colloid susponsion deposition with incomplete crystallization LSGM powder as a starting material. The phase composition and micromorphology of the LSGM film were characterized by X-ray diffraction and scanning electron microscopy. The electrical properties of the LSGM film and the performances of the LSGM film solid oxide fuel cell were also analyzed. The results show that beth the dense LSGM film on the porous anode support, and the required phase composition of the LSGM film were obtained simultaneously by sintering at 1400 ℃ for 6 h. The adhesion between the LSGM film and the porous anode support is very strong. The electrical conductivities of the LSGM film on the porous anode support are 0. 113 and 0. 173 S/cm at 800 and 850℃, respectively. The maximum output power density of the LSGM film cell is 177 mW/cm^2 at 700℃.

A NEW PROBE FOR IDENTIFYING PROPERTIES OF SUPPORTED METAL AND METAL OXIDE CATALYSTS

A novel molecular probe for identifying properties of supported transition metals and metal oxides catalysts was established.The catalytic mechanism of transition metals was proposed.

An intelligent SVM modeling process for crude oil properties prediction based on a hybrid GA-PSO method

Properties prediction of crude oil remains an essential issue for refineries. In this communication, an exhaustive and extendable support vector machine(SVM) intelligent prediction process has been proposed to solve this problem. A novel hybrid genetic algorithm-particle swarm optimization(GA-PSO)method was applied to optimize the SVM model. The optimization process and result demonstrated that the newly proposed GA-PSO-SVM method was more accurate and time-saving than the classical GA or PSO method. Compared with the classical Grid-search SVM, the combined GA-PSO-SVM model appeared to be more applicable for the properties prediction task. The TBP distillation curve fitting was exampled to evaluate the performance of the developed model. The regression result demonstrated the high accuracy and efficiency of the proposed process. The model can be applied in the Industrial Internet as a plugin, and the adaptability and flexibility is demonstrated by the implement of crude oil molecular reconstruction employing the intelligent prediction process.

Local spatial properties based image interpolation scheme using SVMs

Image interpolation plays an important role in image process applications. A novel support vector machines （SVMs） based interpolation scheme is proposed with increasing the local spatial properties in the source image as SVMs input patterns. After the proper neighbor pixels region is selected, trained support vectors are obtained by training SVMs with local spatial properties that include the average of the neighbor pixels gray values and the gray value variations between neighbor pixels in the selected region. The support vector regression machines are employed to estimate the gray values of unknown pixels with the neighbor pixels and local spatial properties information. Some interpolation experiments show that the proposed scheme is superior to the linear, cubic, neural network and other SVMs based interpolation approaches.

Correlation between the surface characteristics of carbon supports and their electrochemical stability and performance in fuel cell cathodes

In this paper,an extensive characterisation of a range of carbon blacks(CB)with similar surface area but different surface chemistry is carried out by flow calorimetry,Raman spectroscopy,dynamic water vapour sorption,instrumental gas analysis,nitrogen adsorption/desorption and high potential chronoamperometry.Using these carbon materials as supports,Pt/CB electrocatalysts are prepared by microwave-assisted polyol-mediated synthesis in gram scale.Structural,morphological and electrochemical properties of the prepared electrocatalysts are evaluated by X-ray diffraction,transmission electron microscopy,rotating disc electrode and in situ fuel cell characterisation of the corresponding membrane-electrode assemblies.The obtained results allow to establish a relationship between surface chemistry and electrochemical properties useful for the design of Pt/C catalyst layers with high performance and stability.

Effect of Ferric Nitrate Loading Mode on Properties of Si_(3)N_(4) Composite MgO-C Refractories Prepared by Nitridation

In order to investigate the effect of the catalyst loading mode on the mechanical properties of Si_(3)N_(4) composite MgO-C refractories prepared by nitridation,fused magnesia,flake graphite,silicon powder,and phenolic resin were used as the main raw materials,and ferric nitrate as the catalyst to prepare refractories by nitriding at 1350℃.The effects of different catalyst supports(silicon powder,silicon powder+phenolic resin)on the formation of Si_(3)N_(4) in MgO-C refractories and the properties of refractories were studied.The results show that the silicon powder+resin catalyst support promotes the participation ofα-Si_(3)N_(4) in the reaction to generateβ-Si_(3)N_(4) and MgSiN_(2),and generates more SiC.However,this loading mode causes more gas to escape from the refractories and loosens the material structure,which reduces the mechanical properties.On the contrary,MgO-C refractories prepared by nitridation with silicon powder-supported catalysts under the same conditions show higher density and better mechanical properties.

Selective hydrogenation of dimethyl toluene-2,4-dicarbamate over supported Rh-based catalysts:Effect of support properties

The selective hydrogenation of dimethyl toluene-2,4-dicarbamate(TDC)to methyl cyclohexyl-2,4-dicarbamate(also called hydrogenated TDC,HTDC)is an essential process for non-phosgene synthesis of methylcyclohexane-2,4-diisocyanate.Herein,we prepared a series of supported Rh-based catalysts by the excessive impregnation method and investigated their catalytic performance for the selective hydrogenation of TDC.The emphasis was put on the influence of support properties on the catalytic performance.Among the prepared catalysts,Rh/g-Al_(2)O_(3)performed the best:a HTDC yield of 88.4%was achieved with a 100%conversion of TDC under the conditions of 100℃,3 MPa and 1 h.Furthermore,Rh/γ-Al_(2)O_(3)could be repetitively used for 4 times without a significant loss of its catalytic activity.TEM,XRD,N_(2)adsorption-desorption,H_(2)-TPR,NH_(3)/CO_(2)-TPD,XPS and ICP characterizations were employed to distinguish the properties of the prepared catalysts and the results were correlated with their catalytic performance.It is indicated that the yield of HTDC shows a positive relevance with the percentage of moderate-to-strong acid sites and the content of Rh^(n+)(n≥3)in the catalysts.High values of the percentage and the content can promote a strong interaction between Rh nanoparticles and the supports,facilitating both the transfer of electrons from Rh to the support and the formation of Rh^(n+)species.This is conducive to activating the benzene ring of TDC and thereby improving the yield of HTDC.

新型混编支架的制备与径向支撑力学行为

背景:编织支架因良好的柔顺性被广泛应用于狭窄动脉的治疗,但在提供足够的径向支撑性能方面存在明显局限。目的:针对单一材料制成的编织支架存在径向支撑力不足的问题,采用不同力学参数的生物可降解材料混合编织支架,探究影响混编支架径向力学性能的影响因素。方法:在镁合金支架中引入铁合金纱线,采用有限元分析法对不同编织参数的混编支架进行参数化分析,通过与0.18 mm直径镁合金纱线制备的普通支架进行对比,评估其径向支撑力、径向回弹率和扩张不均匀性。结果与结论:①当铁合金纱线直径为0.18 mm和0.14 mm时,随着铁合金纱线数量的增多,混编支架的径向支撑力增加;此时,尽管直径0.14 mm铁合金纱线提供的径向支撑力小于同数量的0.18 mm铁合金纱线,但增加细铁合金纱线的数量可以达到与较粗铁合金纱线混编支架相媲美的径向支撑力。当铁合金纱丝直径为0.10 mm时,随着铁合金纱线数量的增加,混编支架的径向支撑力降低。②增大编织角度,混编支架的径向支撑力降低,但其径向回弹率和狗骨率得到了改善。通过降低编织角可以改善小直径铁合金纱线造成的支架径向支撑力不足。③结果显示,在镁合金支架中引入铁合金纱线,可以实现在不增加纱线直径的情况下精确地调整支架的径向力学性能,这不仅克服了单一材料支架的局限性,也为多材料支架的设计提供了新思路。

A Novel Carbon Nanotube-Supported NiP Amorphous Alloy Catalyst and Its Hydrogenation Activity

A carbon nanotube-supported NiP amorphous catalyst （NiP/CNT） was prepared by induced reduction. Benzene hydrogenation was used as a probe reaction for the study of catalytic activity. The effects of the support on the activity and thermal stability of the supported catalyst were discussed based on various characterizations, including XRD, TEM, ICP, XPS, H2-TPD, and DTA. In comparison with the NiP amorphous alloy, the benzene conversion on NiP/CNT catalyst was lower, but the specific activity of NiP/CNT was higher, which is attributed to the dispersion produced by the support, an electron-donating effect, and the hydrogen-storage ability of CNT. The NiP/CNT thermal stability was improved because of the dispersion and electronic effects and the good heat-conduction ability of the CNT support.

Conventional triaxial compression on hollow cylinders of sandstone with various fillings: Relationship of surrounding rock with support

The interaction of surrounding rock with a support system in deep underground tunnels has attracted extensive interest from researchers.However,the effect of high axial stress on tunnel stability has not been fully considered.In this study,compression tests with and without confining pressure were conducted on solid specimens and hollow cylinder specimens filled with aluminium,lead,and polymethyl methacrylate(PMMA)to investigate the strength,deformation and failure characteristics of circular roadways subjected to high axial stress.The influence of the three-dimensional stress on the surrounding rock supported with different stiffness was studied.The results indicate that the strength and peak strain of hollow cylinders filled with PMMA are higher than those of hollow cylinders filled with aluminium or lead,indicating that flexible retaining is beneficial for roadway stability.The results obtained in this paper can contribute to better understanding the support failure of a buried roadway subjected to high axial stress and thus to analyzing and evaluating roadway stability.

Damage Identification in Simply Supported Bridge Based on Rotational-Angle Influence Lines Method

To locate and quantify local damage in a simply supported bridge, in this study, we derived a rotational-angle influence line equation of a simply supported beam model with local damage. Using the diagram multiplication method, we introduce an analytical formula for a novel damage-identification indicator, namely the diff erence of rotational-angle influence linescurvature(DRAIL-C). If the initial stiff ness of the simply supported beam is known, the analytical formula can be effectively used to determine the extent of damage under certain circumstances. We determined the effectiveness and anti-noise performance of this new damage-identification method using numerical examples of a simply supported beam, a simply supported hollow-slab bridge, and a simply supported truss bridge. The results show that the DRAIL-C is directly proportional to the moving concentrated load and inversely proportional to the distance between the bridge support and the concentrated load and the distance between the damaged truss girder and the angle measuring points. The DRAIL-C indicator is more sensitive to the damage in a steel-truss-bridge bottom chord than it is to the other elements.

Carbon-Supported Silver Catalysts for CO Selective Oxidation in Excess Hydrogen

Carbon materials were used as supports for Ag catalysts that are prepared using the conventional wet impregnation method, and their catalytic properties for CO selective oxidation in excess hydrogen at temperatures below 483 K were tested. A variety of techniques, e.g. N2 adsorption, XPS, TPD, UV-Vis DRS, TEM and SEM, were used to determine the influence of physical and chemical properties of the carbon on the properties of Ag catalyst. It was found that defects on the carbon surface served as nucleation sites for silver ions, while functional groups on carbon surface induced their reduction to the metallic form. The formation of silver particles on carbon was governed by homogeneous and/or heterogeneous nucleation during the impregnation and subsequent activation processes. The best catalytic performance was obtained with a Ag/carbon black catalyst with a uniform size distribution of silver nanoparticles （about 12 nm）, moderate BET surface area （with a mesoporous structure）, and a limited amount of carbon-oxygen groups. The research indicates that carbon materials are potentially good supports for silver catalysts for preferential oxidation of CO in excess hydrogen.

Application of support vector machine in the prediction of mechanical property of steel materials

The investigation of the influences of important parameters including steel chemical composition and hot rolling parameters on the mechanical properties of steel is a key for the systems that are used to predict mechanical properties. To improve the prediction accuracy, support vector machine was used to predict the mechanical properties of hot-rolled plain carbon steel Q235B. Support vector machine is a novel machine learning method, which is a powerful tool used to solve the problem characterized by small sample, nonlinearity, and high dimension with a good generalization performance. On the basis of the data collected from the supervisor of hotrolling process, the support vector regression algorithm was used to build prediction models, and the off-line simulation indicates that predicted and measured results are in good agreement.

THE UNIT BALL OF C-ALGEBRA AND DIFFERENTIABILITY OF SUPPORT FUNCTION

In this paper we show that the unit ball of an infinite dimensional commutative C-algebra lacks strongly exposed points, so they have no predual. Also in the second part, we use the concept of strongly exposed points in the Frechet differentiability of support convex functions.