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931.
X. -M. He L. Wang W. -H. Pu J. -G. Ren W. Wu C. -Y. Jiang C. -R. Wan 《Journal of Thermal Analysis and Calorimetry》2008,94(1):151-155
Thermal analysis of sulfurization of polyacrylonitrile (PAN) with elemental sulfur was investigated by thermogravimetry and
differential thermal analysis of the mixture of polyacrylonitrile and elemental sulfur up to 600°C. Due to the volatilization
of sulfur, the different heating rate (10 and 20 K min−1) and different mixture proportion of polyacrylonitrile and elemental sulfur were adopted to run the analysis. The different
heating rates make the DSC curves of sulfur different, but make the DSC curves of PAN similar. In the DSC curve of sulfur
for the heating rate of 20 K min−1 around 400°C, a small exothermic peak occurs at 400°C in the wide endothermic peak around 380∼420°C, indicative of that there
is an exothermic reaction around 400°C. In the DSC curves of the mixture, the peaks around 320°C are exothermic as the content
of sulfur is below 3.5:1 and endothermic as the content of sulfur is over 4:1, indicating that one of the reactions between
PAN and sulfur takes place around 320°C. In the TG curves of the mixture, the mass losses begin at 220°C, and sharply drop
down from 280°C. The curves for the low sulfur content obviously show two steps of mass loss, and curves for the high sulfur
content show only one step of mass loss, indicative of more sulfur is benefit for the complete sulfurization of PAN. This
study demonstrates that the TG/DSC analysis can give the parameter for the sulfurization, even if the starting mixture contains
the volatile sulfur. 相似文献
932.
933.
Arran R. Wood Nicolas Benedetto Nigel Hooker Edward Scullion Paul A. Smith John F. Watts 《Surface and interface analysis : SIA》2008,40(10):1409-1414
The design philosophy and implementation of an ultra high vacuum (UHV), PC controlled, automated in situ fracture stage for a surface analysis system is described. ToF‐SIMS spectra are shown to illustrate the improvement in spectral quality obtained from micro‐compact tension (CT) tests of polymer matrix fracture surfaces produced using the fracture stage in UHV compared to those obtained from a sample tested at air. This system is flexible in that by changing the capacity of the load cell it is possible to reduce or increase maximum loads as the specimen type and material demands. The stage has been designed with instrumental flexibility in mind, utilising commercial SEM‐stub type sample mounts, and can thus be used for AES/SAM and XPS investigations, as well as ToF‐SIMS analysis, in the authors' laboratory. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
934.
金的化学状态对Au/CoCeOx催化剂CO氧化性能的影响 总被引:1,自引:1,他引:0
以CoCeOx复合氧化物为载体,采用沉积沉淀法制备了负载型的金催化剂,并通过不同温度的预处理控制Au的化学状态. 使用粉末X射线衍射、高分辨透射电子显微镜、程序升温还原和X射线光电子能谱对催化剂进行了表征,考察了在室温条件下该系列催化剂的一氧化碳氧化性能. 结果表明, Au/CoCeOx催化剂的CO氧化性能与催化剂表面Au 的含量成正比, Au 可能是反应的主要活性物种. 添加水汽对反应有一定的促进作用,但由于Au 不能稳定存在,特别是当催化剂表面Au 的含量过高时,在水汽的作用下Au 迅速发生歧化反应,使得催化剂的性能下降. 相似文献
935.
Wenju Zhu Mingyang Yang Qing Wang Xiaohan Zhang Dongxiang Li Zelong Xu Shuixia Liu Zhao Dai 《中国化学会会志》2023,70(2):159-170
The chelating ligands of boric acid and amino trimethyl phosphonate prepared a novel flame retardant (BAP) for the cotton fabric. A stable chemical and coordination bond was formed on the surface of the cotton fibers by a simple three-curing finishing process to make the fabric exhibits excellent durable flame retardancy. Cotton fabrics' tensile strength and whiteness got substantially retained after BAP treatment. 90 g/L BAP-treated samples (3 curing times, 50 laundry cycles) showed good flame retardancy and durability, holding the largest limit oxygen index, 29.7%, and the shortest damage length, 61 mm. A condensed phase and gas phase synergistic flame retardant mechanism was concluded by thermogravimetric, cone calorimeter tests, and thermogravimetric infrared analysis. 相似文献
936.
ZHAO Jinjin LI Wei WANG Xuechen WEI Xiao ZHU Huiwen QU Wenshan MEN Dandan GAO Zhixiang WEI Bin GAO Hanfei WU Yuchen 《高等学校化学研究》2023,39(1):121-126
Organic memristors with low power consumption, fast write/erasure speed, and complementary metal-oxide-semiconductor(CMOS) compatibility have attracted tremendous attention to mimic biological synapses to realize neuromorphic computation in recent years. In this paper, organic resistive switching memory(ORSM) based on (Z)-3-(naphthalen-2-yl)-2-(4-nitrophenyl)acrylonitrile(NNA) and polymer poly(N-vinylcarbazole)(PVK) composite film was prepared by spin-coating method. Device performance based on NNA:PVK composite films with different mass fractions of NNA were systematically investigated. The ORSM based on PVK:40%(mass fraction) NNA composite film exhibited non-volatile and bipolar memory properties with a switching ratio(Ion/Ioff) of 24.1, endurance of 68 times and retention time of 104 s, a “SET” voltage(Vset) of -0.55 V and a “RESET” voltage(Vreset) of 2.35 V. The resistive switching was ascribed to the filling and vacant process of the charge traps induced by NNA and the inherent traps in PVK bulk. The holes trapping and de-trapping process occurred when the device was applied with a negative or positive bias, which caused the transforming of the conductive way of charges, that is the resistive behaviors in the macroscopic. This study provides a promising platform for the fabrication of ORSM with high performance. 相似文献
937.
Alexandra Belcovici Carmen Ioana Fort Laura Elena Mureşan Ioana Perhaiţa Gheorge Borodi Graziella Liana Turdean 《Electroanalysis》2023,35(5):e202200395
ZnO nanoparticles (ZnO-NP) were prepared by a facile precipitation technique using di-isopropyl amine as precipitating agent. The morpho-structure and porosity of the as-prepared nano-powder were investigated by FT-IR analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), and BET analysis. By drop-casting, a composite film was deposited to obtain ZnO-NP-Nafion/GCE modified electrode. The modified electrode was investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and square wave anodic stripping voltammetry (SWASV) for the detection of Pb2+, Cd2+, Cu2+, and Fe3+, and it was successfully applied for the detection of Pb2+ and Cu2+ in real water samples. 相似文献
938.
An electrode of hydrated tungsten oxide (WO3?nH2O) embedded chitosan‐co‐polyaniline (CHIT‐co‐PANI) composite was electrochemically prepared on an indium tin oxide (ITO) coated glass surface using mineral acid as a supporting electrolyte. The resulting CHIT‐co‐PANI/WO3?nH2O/ITO electrode was characterized using ultraviolet‐visible spectroscopy (UV‐vis), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV), and scanning electron microscopy (SEM). The composite electrode exhibited a three‐dimensional nanofibrous structure with the diameter of the nanofibers ranging from 20 to 100 nm. The CHIT‐co‐PANI/WO3?nH2O/ITO electrode allowed for the low potential detection of NO2 gas in acidic medium. The NO2 gas sensing characteristics were studied by measuring change in the current with respect to concentration and time. Using the CHIT‐co‐PANI/WO3?nH2O/ITO electrode, NO2 gas was detected electrochemically without interference at pH 2.0 and 0.25 V vs. Ag/AgCl. The current of the electrochemical cell with the CHIT‐co‐PANI/WO3?nH2O/ITO electrode decreased linearly with an increase in NO2 gas concentration in a range from 100 to 500 ppb with a response time of eight seconds. 相似文献
939.
Synthesis and photophysical properties of novel organic–inorganic hybrid materials covalently linked to a europium complex 总被引:2,自引:0,他引:2
Xianmin Guo Huadong Guo Lianshe Fu Hongjie Zhang L.D. Carlos Ruiping Deng Jiangbo Yu 《Journal of photochemistry and photobiology. A, Chemistry》2008,200(2-3):318-324
A novel sol–gel derived hybrid material (classed as Eu-DBM-Si) covalently grafted with Eu(DBM-OH)3·2H2O (where DBM-OH = o-hydroxydibenzoylmethane) was prepared through the primary β-diketone ligand DBM-OH. All the synthesized ligands were characterized by 1H NMR, elemental analyses and Fourier transform infrared spectra (FTIR). The resultant Eu-DBM-Si material exhibited good transparent and homogenous property. Compared to the Eu-DBM hybrid prepared by physically doped silicon dioxide with Eu(DBM-OH)3·2H2O, the Eu-DBM-Si hybrid presented more efficient ligand-to-Eu3+ energy transfer and a significant improvement in the measured emission quantum yield. Furthermore, the photophysical properties of these hybrid materials, such as the photoluminescence (PL) spectra, PL intensities, symmetry properties, lifetime decays, and Judd-Ofelt parameters were also investigated in detail. 相似文献
940.
An additive-free Watts type bath containing micron- and nano-SiC particles (1 μm and 20 nm respectively), as well as ultrafine-WC
particles (200 nm), was used for the production of pure Ni and nickel matrix composite electrocoatings under both direct and
pulse current conditions. Moreover, nickel nanocrystalline deposits were obtained from a Watts type bath containing small
amounts of 2-butyne-1,4-diol, in order to investigate the combined advantages of additives and pulse technique on the properties
of the deposits. The influence of the variable electrolysis parameters, the particle size and the organic additive concentration
on the surface morphology, the structure and properties of the deposits were discussed. It has been proved that the application
of pulse electrodeposition affects drastically the structural characteristics and properties of the deposits and under well-defined
conditions could lead to the preparation of nanostructured materials with improved mechanical properties.
Published in Russian in Elektrokhimiya, 2008, Vol. 44, No. 6, pp. 802–811.
The text was submitted by the authors in English. 相似文献