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1.
Nikolay N. Nikitenkovt  A.  N.  Nikitenkov  Yu.  I.  Turin  I.  V.  Dushkin  V.  S.  Sypchenko  O.  V.  Vilhivskaya 《化学与化工:英文版》2014,(2):187-190
In this study, thin films were produced by magnetron sputtering NC (nanocrystalline) specimens of titanium saturated in hydrogen and were evaluated by layer-by-layer SIMS (secondary ion mass spectrometry) and Raman spectroscopy. Due to magnetron sputtering, the chemical composition of the films was non-homogeneous and was variable among layers. Moreover, in the deposition of specimens saturated with hydrogen, hydrogen diffused throughout the depth of the film; diffusion, however, was restricted to the area near the film-substrate interface, affecting less than 50% of the thickness of the film.  相似文献   

2.
Pb1-xSrxTiO3 (0≤x≤0.9) thin films on Si (100) substrate were prepared by the sol-gel process and their characteristics were investigated as a function of strontium content(x). With increasing of the strontium content, the tetragonality (c/a) was slightly decreased, the splitting peaks become less prominent and the splitting peaks tend to merge into a single peak. Furthermore, the grain size of the films was systematically reduced with the increase in strontium content.  相似文献   

3.
The oxidation kinetics, surface morphology and phase structure of oxide films grown on 25Cr20Ni alloy in air-H2O and H2-H2O atmospheres at 900 °C for 20 h were investigated. The anti-coking performance and resistance to carburization of the two oxide films were compared using 25Cr20Ni alloy tubes with an inner diameter of 10 mm and a length of 850 mm in a bench scale naphtha steam pyrolysis unit. The oxidation kinetics followed a parabolic law in an air-H2O atmosphere and a logarithm law in a H2-H2O atmosphere in the steady-state stage. The oxide film grown in the air-H2O atmosphere had cracks where the elements Fe and Ni were enriched and the un-cracked area was covered with octahedral-shaped MnCr2O4 spinels and Cr1.3Fe0.7O3 oxide clusters, while the oxide film grown in the H2-H2O atmosphere was intact and completely covered with dense standing blade MnCr2O4 spinels. In the pyrolysis tests, the anti-coking performance and resistance to carburization of the oxide film grown in the H2-H2O atmosphere were far better than that in the air-H2O atmosphere. The mass of coke formed in the oxide film grown in the H2-H2O atmosphere was less than 10% of that in the air-H2O atmosphere. The Cr1.3Fe0.7O3 oxide clusters converted into Cr23C6 carbides and the cracks were filled with carbon in the oxide film grown in the air-H2O atmosphere after repeated coking and decoking tests, while the dense standing blade MnCr2O4 spinels remained unchanged in the oxide film grown in the H2-H2O atmosphere. The ethylene, propylene and butadiene yields in the pyrolysis tests were almost the same for the two oxide films.  相似文献   

4.
Silicoaluminophosphates SAPO-11 molecular sieves with small particle size and hierarchical pores were synthesized using a directing agent method. The effect of crystallization time on the crystal structure, morphology, pore structure properties and acid properties of SAPO-11 molecular sieves were investigated. The results of XRD, SEM, BET and NH3-TPD showed that the SAPO-11 molecular sieves with fine and uniform morphology could be synthesized in a shorter crystallization time used the directing agent method, which just unlike the SAPO-11 molecular sieves synthesized with the conventional method. With the crystallization time increased, the particle size of SAPO-11 molecular sieve was significantly reduced, and the mesoporous structure (intercrystalline pore) was generated between the particles. Furthermore, the external specific surface area and the total specific surface area reached 81.7 m2g-1 and 192.0 m2g-1, respectively, which effectively reduce the pore mass transfer resistance, significantly increase the number of acid active sites. The results of n-dodecane hydroisomerization revealed that the Pt/SAPO-11 prepared with the novel method exhibited higher catalytic activity and better hydroisomerization selectivity than the Pt/SAPO-11 synthesized by conventional hydrothermal method. Thus, the small particle molecular sieve has promising industrial applications as catalyst support.  相似文献   

5.
Polyvinyl Pyrrolidone(PVP)/(Lanthanum nitrate and Manganese acetate) composite microfibres were fabricated by electrospinning technique. SEM micrographs indicated that the surface of the composite microfibres was smooth, and the diameter of the microfibres was in the range of 1-2μm. XRD analysis revealed that the composite microfibres were amorphous in structure. LaMnO3 ultrafine fibres were fabricated by calcination of the PVP/[La(NO3)3+Mn(CH3COO)2] composite microfibres, The diameters of LaMnO3 ultrafine fibres were smaller than those of the PVP/[La(NO3)3+Mn(CH3COO)2] composite microfibres. The surface of the LaMnO3 ultrafine fibres became coarse with the increase of calcination temperatures. LaMnO3 hollow-centered and porous ultrafine fibres formed by nanoparticles were acquired when firing temperature was 600-900℃. SEM analysis indicated that the diameters of the synthesized LaMnO3 ultrafine fibres were in the range of 500-800 nm with the mean wall thickness of 100 nm, and their lengths were greater than 100 ~tm. XRD analysis revealed that the crystal structure of LaMnO3 ultrafine fibres was orthorhombic with space group Pbnm. Possible formation mechanism for LaMnO3 ultrafine fibres was preliminarily proposed.  相似文献   

6.
This paper describes the conductivity modifications induced by heavy ion implantation in pyrolysis products obtained by thermal treatment of polyacrylonitrile (PAN) thin films at temperatures of 435℃ (PAN435) and 750℃ (PAN750) under vacuum. Ionic species having different chemical reactivities such as Kr, As, Cl. and F ions were utilized to allow interpretation of the conductivity' data either in terms of implantation induced molecular rearrangements or in terms of specific chemical doping effects. The temperature dependence of conductivity in the range between 25-3000C followed nearly a simple activation conduction relationship from which the temperature coefficients of resistivity (ct) were determined. In this temperature range, PAN750 provided the smallest α value compared with ion implanted PAN750 or with products obtained at the lower pyrolysis temperature. However. the corresponding lowest rate of conductivity change with temperatures (0.49%/℃) obtained in this study far exceeds the specification value required for thin film resistor applications (〈 0.1%/℃).  相似文献   

7.
EPD (electrophoretic deposition) technique has been shown as an effective method to produce thin ore thick layers at voltage 5-100 V onto Ni conductive substrate. The aim of this study is to use the EPD method to fabricate films from suspensions BaTiO3. The effects of the EPD process parameters such as the suspension concentration, deposition time, electrical field strength on the specific EPD deposited weight, morphology particles were used. The surface microstructures of the as-deposited films were investigated by SEM (scanning electron microscopy). A homogeneous microstructure was obtained at applied electric field of 100 V and I min of deposition time at an electrode distance of 1.0 cm.  相似文献   

8.
Two novel ashless and non-phosphorus S, B-containing morpholine derivatives, MBOC and MBOD, were prepared and their tribological behaviors in rapeseed oil (RSO) were evaluated using a four-ball tester. Thermal degradation tests were conducted to identify their thermal stabilities using a thermo-gravimetric analyzer. The worn surfaces of the steel balls were investigated by scanning electron microscopy (SEM). The results indicated that the additives possessed high thermal stabilities and good load-carrying capacities. Moreover, they both had good anti-wear and friction reducing property at a relatively high concentration (1.5 m%) and under all test loads. The results of XPS analyses illustrated that the prepared compounds as additives in RSO could form a protective film containing inorganic sulfide, sulfate, oxidized compounds and organic nitrogen-containing compounds on the metal surface during the sliding process.  相似文献   

9.
On the basis of thin film lubrication theory, the influence of fluid film(disordered film), ordered film and adsorbed film on tribological behavior of lubricating oil in thin-film lubrication(TFL) regime was studied. The μ-L(friction coefficient versus load) curves of different oil viscosity and additive dosage were obtained by a high frequency reciprocating test rig and the adsorption capacity of additive on steel surface were measured by QCM-D. Based on the Stribeck curve and thin film lubrication theory model, some conclusions can be drawn up, namely:(1) The μ-L curves and the parameters of L0 and μ0, obtained from the high frequency reciprocating test rig with ball-disc contact, can be used to study tribological behaviors of lubricating oil under TFL conditions.(2) In comparison with the high viscosity base fluid, the lower one can enter into TFL regime under lower load and keeps a lower friction coefficient in TFL regime.(3) The polar molecules in additive formulation produce ordered adsorbed layer on steel surface to reduce friction coefficient. And in TFL regime, the molecule's polarity, layer thickness and saturation degree on steel surface probably can influence lubricant's tribological behaviors between the moving interfaces. Moreover, the further study would be focused on the competitive adsorption of different additives, the formation of dual- and/or tri-molecular adsorption layers, and other aspects.  相似文献   

10.
An overview of the advances in studies on tribology of molecular deposition (MD) films is presented here to summarize the studies of nanofrictional properties, adhesion, wear and mechanical behavior, as well as the molecular dynamics simulation of nanotribological properties of the film in the last decade. Some key research topics which need to be investigate further are addressed.  相似文献   

11.
Decarburized samples of grain oriented silicon steel were coated with alone and blended magnesias and submitted to the high temperature annealing. The magnesias and their blendings were characterized using granulometry measurements, ignition loss and reactivity tests. After high temperature annealing, forsterite film morphology, magnetic properties and Goss deviation were also analyzed. Better magnetic properties and sharper Goss orientation were found in samples which had used blended magnesias. These results are explained by the magnesias particle size distributions, forsterite film formation and rate of inhibitors release.  相似文献   

12.
Pyrolysis experiments were conducted on lacustrine organic-rich shale from Cangdong Sag in Bohai Bay Basin, China, to investigate the impact of hydrocarbon generation on shale pore structure evolution.Thermal evolution is found to control the transformation of organic matter, hydrocarbon products characteristics, and pore structure changes. Furthermore, pore volume and specific surface area increase with increasing maturity. In low-mature stage, the retained oil content begins to increase, pore ...  相似文献   

13.
Two kinds of cycloalkoxy silane compounds were synthesized and used as the internal electron donors (IEDs) of supported Ziegler-Natta catalyst for ethylene polymerization to produce polyethylene with broader molecular weight distribution (MWD), The effect of the structure and the amount of these IEDs on the polymerization performance was in- vestigated. The results implied that the molecular weight distribution of the obtained polyethylene could be adjusted by the incorporation of IEDs. SEM result showed that the morphology of catalyst particle was spherical and uniform in size distribution. The titanium content of these catalysts was higher, the active TiCl4 species were easily anchored on the support than that without adding IED, which was determined by ICE The GPC result confirmed that the polyethylene with broader molecular weight distribution in the range of from 23.4 to 25.6 was obtained using triethoxy-(-cyclopentyloxy)-silane (ED1) and triethoxy-(-cyclohexyloxyl)- silane (ED2) as the internal electron donors.  相似文献   

14.
In order to acquire LaNiO3 nanofibers with particular morphology and structure, electrospinning technique, for the first time, was successfully applied to fabricate LaNiO3 nanofibers in the paper. Polyvinyl alcohol(PVA)/ [La(NO3)3+Ni(CH3COO)2] composite nanofibers were fabricated by electrospinning, and polycrystalline LaNiO3 nanofibers were prepared by calcination of the PVA/[La(NO3)3+Ni(CH3COO)2] composite nanofibers at 6000C for 10 h. The samples were characterized by using thermogravimetric-differential thermal analysis (TG-DTA), X-ray diffraction spectrometry(XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FTIR). The results showed that PVA/[La(NO3)3+ Ni(CH3COO)2] composite nanofibers were amorphous in structure, and pure phase LaNiO3 nanofibers were trigonal with space group R3m. The surface of as-prepared composite nanofibers was smooth, and the diameter was about 200 nm. The diameter of LaNiO3 nanofibers was smaller than that of the relevant composite fibers. The surface of the LaNiO3 nanofibers becomes coarse with the increase of calcination temperatures. The diameter of LaNiO3 nanofibers was ca. 80 nm, and the length was greater than 100μm. The mass of the sample remained constant when the temperature was above 463℃, and the total mass loss percentage was 90.9%. Possible formation mechanism of LaNiO3 nanofibers was preliminarily proposed.  相似文献   

15.
PMF-PZN-PZT (0.01Pb(Mol/3Fe2/3)O3-xPb(Znl/3Nb2/3)O3-(O.99-x)P(Zro53Tio 47)03 piezoelectric ceramics), where x = 0.00 0.01, 0.03, 0.05 and 0.07 were prepared by a conventional mixed-oxide method. The results show that the pure peroveskit phase forms in these ceramics. X-ray diffraction analysis indicated that the phase of the material is a MPB (morphotropic phase boundary) structure. The effects of PZN content on the crystal structure and electrical properties were investigated, optimal dielectric properties were achieved at composition x = 0.07 ceramics by calcination at 800 ℃ and sintering at 1,180 ℃, with a curie temperature of approximately 430 ℃. These results clearly show the significance of PZN in controlling the electrical responses of the PMF-PZN-PZT system.  相似文献   

16.
An interfacially active cobalt complex,cobalt dodecylbenzenesulfonate,was synthesized.Elemental analysis,atomic absorption spectroscopy,Fourier transform infrared spectroscopy(FT-IR),thermogravimetric analysis,and surface/interfacial tension determination were performed to investigate the properties of the catalyst.Results showed that the synthesized catalyst showed active interfacial behavior,decreasing the surface tension and interfacial tension between heavy oil and liquid phase to below 30 and 1.5 mN/m,respectively.The catalyst was not thermally degraded at a temperature of 400 ℃,indicating its high thermal stability.Catalytic performance of the catalyst was evaluated by carrying out aquathermolysis.The viscosity determination showed that the viscosity of the heavy oil decreased by 38%.The average molecular weight,group compositions,and average molecular structure of various samples were analyzed using elemental analysis,FT-IR,electrospray ionization Fourier transform ion cyclotron resonance(ESI FT-ICR MS),and ~1H nuclear magnetic resonance.Results indicated that the catalyst could attack the sulfur- and O_2-type heteroatomic compounds in asphaltene and resin,especially the compounds with aromatic structure,leading to a decrease in the molecular weight and then the reduction in the viscosity of heavy oil.Therefore,the synthesized catalyst might find an application in catalytic aquathermolysis of heavy oil,especially for the high-aromaticity heavy oil with high oxygen content.  相似文献   

17.
The lubricating characteristics of CVTF (continuously variable transmission fluid) mixed with a multi-functionalcomplex additive were studied. The said complex additive contained an organic borate ester and a new type of friction improvercomprising phosphorus element and poly-methylmethacrylate (PMMA), and a viscosity index improver. The viscosity-pressure characteristics were evaluated by a high-pressure quartz viscometer, and the anti-wear property was investigatedby a four-ball friction tester. The mechanism of lubrication by the CVTF was studied using X-ray photoelectron spectroscopy(XPS). The results showed that CVTF T10, which contained a multi-functional complex additive, exhibited excellentproperties, featuring greater solidification pressure and pressure-viscosity coefficient, improved oil film strength, and lowwear value. These attributes meet the special CVTF requirements for “high friction and low wear” that make it possible toprovide both traction and lubrication. The lubricating mechanism was varied using different functional elements, such asinert and active elements. Sulfur and phosphorus are active extreme pressure elements that can react on the metal frictionsurface and produce an extreme pressure lubrication film. Boron is an inert functional element and does not react upon themetal surface; boron is only adsorbed onto the metal surface to act as a lubricant for adsorption film and fillers.  相似文献   

18.
The drying of aqueous poly(ethylene oxide)(PEO) droplet on a substrate at different temperatures was studied.It was found that the contact line receded when the substrate was at a temperature above 60 oC.Different nucleation behavior and surface profiles of PEO films were found in different droplets drying processes.The rheological properties of aqueous PEO solutions were studied to understand the mechanism of contact line recession and micro-flow in drying aqueous PEO droplets.It was found that at low temperature,the contact line was static because of great viscous stress;while at high temperature,it receded because of great Marangoni force and the decrease of viscous stress.It was indicated that Marangoni convection was inhibited by the outward capillary flow and viscous stress at low temperature,whereas it became dominant at high temperature.Two types of mechanism for surface profiles and nucleation of PEO film from drying droplets are proposed,providing a theoretical guide for polymer solution application in oil and gas foam flooding technology.  相似文献   

19.
The oxidative dehydrogenation of isobutane to isobutene was examined for the use in the preparation of FSM-16 and related compounds doped by chromium with expectations that a yield of isobutene of greater than 8% could be achieved. The activity depended on the molding procedure of the catalyst and the doping method of the chromium species. In the present study, 8.8% and 8.3% of the yield of isobutene were obtained at 0.75 h and 6 h on-stream for the catalyst (Cr-loading; 6.2 wt.%) molded using wet treatment hut not pressurization treatment, in which the chromium species were directly added into the aqueous solution containing raw FSM-16 (hydrated sodium silicate powder) at an initial stage of the catalyst preparation. The structure information was based on XRD (X-ray diffraction), the specific surface area was determined using a conventional BET (Brunauer-Emmett-Teller) nitrogen adsorption and the loading of chromium was estimated using ICP (inductively coupled plasma). All those parameters combined with the molding method indicated that the catalytic activity was more influenced by the loading of chromium into bulk but not on surface of the catalyst rather than by the hexagonal structure of FSM-16 and the surface area.  相似文献   

20.
The study of the chlorite coatings always attracts scholars in China and other countries because the chlorite coatings play an important role in the preservation of residual primary pores in sandstone reservoirs.At present,the study of the origin and the controlling factors is relatively few.The occurrence,time of formation,genesis,controlling factors,and the mechanism of chlorite coatings inhibiting quartz overgrowths were studied in detail with thin section and SEM analysis.Samples were from the sandstone reservoirs of the T3x Group in the Baojie area,the transitional zone from the middle to the south of Sichuan Basin.The results indicate that the chlorite coatings on the walls of the pore spaces are oriented perpendicular to grain surfaces in the form of isopachous(even-thickness) grain-coating,while the chlorite coatings at the contacts between adjacent detrital grains are arranged with a preferred orientation tangential to the surface of detrital grains.The chlorite coatings were formed in the eogenetic stage.They were formed by recrystallization of Fe-rich clay films during the syndepositional period,and chlorite cements would be recrystallized after the coatings’ formation.The formation of chlorite coatings was mainly controlled by the depositional environment,provenance conditions,and diagenetic environment.The presence of chlorite coatings could result in the preservation of primary pores in deeply buried sandstone reservoirs by effectively inhibiting quartz overgrowths and the development of compaction and pressure solution.  相似文献   

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