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TEM Measurements (tem + measurement)
Selected AbstractsQuasi in situ Ni K -edge EXAFS investigation of the spent NiMo catalyst from ultra-deep hydrodesulfurization of gas oil in a commercial plantJOURNAL OF SYNCHROTRON RADIATION, Issue 4 2010Yusuke Hamabe Ni species on the spent NiMo catalyst from ultra-deep hydrodesulfurization of gas oil in a commercial plant were studied by Ni K -edge EXAFS and TEM measurement without contact of the catalysts with air. The Ni,Mo coordination shell related to the Ni,Mo,S phase was observed in the spent catalyst by quasi in situ Ni K -edge EXAFS measurement with a newly constructed high-pressure chamber. The coordination number of this shell was almost identical to that obtained by in situ Ni K -edge EXAFS measurement of the fresh catalyst sulfided at 1.1,MPa. On the other hand, large agglomerates of Ni3S2 were observed only in the spent catalyst by quasi in situ TEM/EDX measurement. MoS2 -like slabs were sintered slightly on the spent catalyst, where they were destacked to form monolayer slabs. These results suggest that the Ni,Mo,S phase is preserved on the spent catalyst and Ni3S2 agglomerates are formed by sintering of Ni3S2 species originally present on the fresh catalyst. [source] X-ray investigation of CdSe nanowiresPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2009Özgül Kurtulu Abstract CdSe nanowires (NWs) have been prepared by a solution,liquid,solid (SLS) approach using Bi nanocatalysts. Structural characterization has been performed by X-ray powder diffraction providing an admixture of wurtzite and zinc-blende (ZB) structure units separated by different types of stacking faults. The relative contributions of ZB type stacking units within the NWs were determined to be in the order of 3,6% from a set of ratios of reflection intensities appearing in only wurtzite structure to those appearing in both ZB and wurtzite (W) structure. In addition, the anisotropy of domain size within the NWs was evaluated from the evolution of peak broadening for increasing scattering length. The coherence lengths along the growth direction are found to be changing between 16 and 21,nm, smaller than the results obtained from TEM measurement, while the NW diameters are determined to be between 5 and 8,nm which is in good agreement with TEM inspection. [source] Microstructure of A -plane InN grown on R -plane sapphire by ECR-MBEPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2007S. Watanabe Abstract We used electron cyclotron resonance plasma-excited molecular beam epitaxy (ECR-MBE) to grow A -plane (110) InN on nitridated R -plane (102) sapphire and then measured the structural properties using transmission electron microscopy (TEM). We determined the epitaxial relationship between A -plane InN and R -plane sapphire to be (110)InN // (102)sapphire and [100]InN // [110]sapphire. Moreover, the results indicated that the nitridation of the sapphire produced a (001) cubic AlN layer, and this layer caused the subsequent InN to have its a-axis normal to the interface. Also, by using two diffraction vector orientations in the TEM measurement, we found that dislocations with a screw component had a density of about 5 × 1010 cm,2, which is about ten times higher than that with an edge component. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Equal effects of gelatin and hydroxyethyl starch (6% HES 130/0.42) on modified thrombelastography in childrenACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 3 2009W. A. OSTHAUS Background: Artificial colloids are frequently used to prevent or treat circulatory failure due to hypovolaemia. Whereas gelatin has been shown not to affect coagulation besides its haemodilutional effect, hydroxyethyl starches (HES) have additional negative effects on haemostasis. The third-generation HES solutions have been developed to minimise these effects. We therefore conducted a prospective, randomised study, to verify the hypothesis that a 6% HES 130/0.42/6 : 1 and a 4% gelatin infusion influences modified thrombelastography (TEM) parameters in children in the same manner and to the same extent. Methods: A total of 50 paediatric patients aged 0,12 years scheduled for surgery were assigned to receive either 10 ml/kg HES 130/0.42 or gelatin. Blood gas analysis, haemodynamic parameters and TEM measurements were performed before and after colloid administration. Results: Patient characteristics, indications/surgical procedures and the main results obtained from blood gas analysis were comparable between the two groups. After administration of either gelatin or HES, all TEM parameters, except for clotting time, indicated impaired coagulation whereas the mean values of all TEM parameters remained within the normal ranges. Comparing the gelatin and HES 130/0.42/6 : 1 groups, none of the measured TEM parameters was found to show between-group differences at baseline or after colloid infusion. Conclusion: In conclusion, we could demonstrate that the investigational product, HES 130/0.42/6 : 1 solution, administered at a dosage of 10 ml/kg to children, had comparable effects on coagulation monitored with TEM as a gelatin solution. Perioperative administration of HES 130/0.42/6 : 1 does not alter coagulation to an extent above and beyond the effect of haemodilution. [source] Ethylene polymerization behavior of Cr(III)-containing montmorillonite: Influence of chromium compoundsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2009Kazuhiro Yamamoto Abstract Montmorillonite was treated with Cr(NO3)3, Cr(acetate)3, and Cr(acac)3 to give three catalyst precursors, Cr-MMT-1, Cr-MMT-2, and Cr-MMT-3, respectively. Application of these catalysts to the ethylene polymerization reaction revealed Cr-MMT-1 to be much more reactive than the other two while the molecular weight distributions of the polymers were practically the same. Elemental analysis, XRD, and TEM measurements suggested that chromium occupied the interlayer section in Cr-MMT-1 and mostly the outer surface region for the other two catalysts. Aluminosilicate-supported Cr catalysts exhibited reactivity similar to that of Cr-MMT-2 and Cr-MMT-3. However, more of the low-molecular-weight polymer was formed. These data suggested that there is a relationship between the sites of the Cr ions and catalytic reactivity, and between supporting solid identity and molecular weight distribution of the polymer. The use of n -Bu2Mg and Et2Zn in the place of Et3Al led to lower activity but gave polymers of narrower molecular weight distribution, with more of the high-molecular-weight material. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2272,2280, 2009 [source] Self-Assembly of Large Multimolecular Micelles from Hyperbranched Star CopolymersMACROMOLECULAR RAPID COMMUNICATIONS, Issue 5 2007Haiyan Hong Abstract This work focused on the synthesis and aqueous self-assembly of a series of novel hyperbranched star copolymers with a hyperbranched poly[3-ethyl-3-(hydroxymethyl)oxetane] (HBPO) core and many linear poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) arms. The copolymers can synchronously form unimolecular micelles (around 10 nm) and large multimolecular micelles (around 100 nm) in water at room temperature. TEM measurements have provided direct evidence that the large micelles are a kind of multimicelle aggregates (MMAs) with the basic building units of unimolecular micelles. It is the first demonstration of the self-assembly mechanism for the large multimolecular micelles generated from the solution self-assembly of hyperbranched copolymers. [source] Construction of Polycation-Based Non-Viral DNA Nanoparticles and Polyanion Multilayers via Layer-by-Layer Self-Assembly,MACROMOLECULAR RAPID COMMUNICATIONS, Issue 20 2005Kefeng Ren Abstract Summary: The multilayers of polycation-based non-viral DNA nanoparticles and biodegradable poly(L -glutamic acid) (PGA) were constructed by a layer-by-layer (LbL) technique. Poly(ethyleneimine) (PEI) was used to condense DNA to develop non-viral DNA nanoparticles. AFM, UV-visible spectrometry, and TEM measurements revealed that the PEI-DNA nanoparticles were successfully incorporated into the multilayers. The well-structured, easily processed multilayers with the non-viral DNA nanoparticles may provide a novel approach to precisely control the delivery of DNA, which may have great potential for gene therapy applications in tissue engineering, medical implants, etc. A TEM image of the cross section of a (PGA/PEI-DNA nanoparticle)20 multilayer. [source] | |||||||||||||