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51.
The thermal stability of members of several series of polyitaconates has been assessed using thermogravimetric and thermal volatilisation techniques. From these data general degradation patterns have been established. The poly (di-n-alkyl itaconates) are stable up to 570K before chain breakdown occurs. The poly(mono-n-alkyl itaconates) are less stable and undergo a dehydration/de-esterification reaction at 430K which results in the formation of anhydride structures. This reaction can be suppressed by the formation of the salts. In the copolymers, salt formation also leads to increased stability but the range of copolymers studied was too restricted to draw general conclusions about their thermal behaviour. 相似文献
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Uniform fine particles of nickel basic carbonate were synthesized by heating, aqueous solution containing 0.08 mol dm−3 nickel sulfate and 0.8 mol dm−3 urea, at 85°C for various periods of time. These particles were then coated with copper compound by heating them in aqueous
dispersion, containing urea and copper nitrate, at 85°C. The coating material was found to be amorphous and was composed of
Cu2(OH)2CO3. The coating mixture, when heated under similar conditions in the absence of the dispersed cores, produced greenish dispersion
of the precipitated particles [coating precursor solids]. The later were also amorphous in nature and had the same chemical
composition [Cu2(OH)2CO3] as that of the coating material of the coated particles. Air-dried core, coated, and coating precursor materials were calcined
at 700°C for 1 h at the heating rate of 5°C min−1 in the air atmosphere, which converted them into NiO, NiO[core]/CuO[coating], and CuO, respectively. Scanning electron microscopic examination showed no sintering occurred in all these solids during
the calcinations process and the particles retained their identities to a significant extent. 相似文献
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The synthesized polyaniline (PANI) is doped with different concentrations of Samarium(III) chloride (SmCl3). The electrical conductivity of doped PANI samples has been measured in the temperature range (300–400K). It has been found that dc conductivity increases with the increase of dopant concentration. Different parameters, based on the conductivity, such as pre‐exponential factor (σ0) and activation energy (ΔE) have also been calculated. These parameters exhibit information about the nature and suitability of the dopant. Doped samples are characterized by FTIR and photoluminescence studies, which show the interaction of dopant with PANI. Two sharp peaks of different intensities from PL spectra at 388 and 604nm have appeared in doped PANI, which might be due to the effect of SmCl3. It has been observed that SmCl3 (dopant) shows noticeable changes in the electrical and spectroscopic properties of doped PANI. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
56.
Zeeshan Nawaz Xiaoping Tang Qiang Zhang Dezheng Wang Wei Fei 《Catalysis communications》2009,10(14):1925-1930
The Pt–Sn-based catalyst was intensified using SAPO-34 as support for direct propane dehydrogenation to propylene. The catalyst was prepared by sequential impregnation method and characterized by XRF, BET, XRD, NH3-IR, NH3-TPD, H2-TPR, HR-TEM and O2-pulse coke analysis. NH3-TPD, IR spectra and XRD results suggested that the doping of metals on SAPO-34 did not affect its acidic strength and structural topology of support, respectively. Propylene selectivity of 94% and total olefins selectivity greater than 97% was achieved using Pt–Sn/SAPO-34. The results were compared with Pt–Sn/ZSM-5 under identical conditions. The possible reasons for improvement were the larger surface area, shape selectivity and particular by suitable acidity of SAPO-34. 相似文献
57.
Using full 3D TCAD, an evaluation of process parameter space of bulk FinFET is presented from the point of view of DRAM, SRAM and I/O applications. Process and device simulations are performed with varying uniform fin doping, anti-punch implant dose and energy, fin width, fin height and gate oxide thickness. Bulk FinFET architecture with anti-punch implant is introduced beneath the channel region to reduce the punch-through and junction leakage. For 30 nm bulk FinFET, anti-punch implant with low energy of 15 to 25 keV and dose of 5.0 × 1013 to 1.0 × 1014 cm−2 is beneficial to effectively suppress the punch-through leakage with reduced GIDL and short channel effects. Our simulations show that bulk FinFETs are approximately independent of back bias effect. With identical fin geometry, bulk FinFETs with anti-punch implant show same ION-IOFF behavior and approximately equal short channel effects like SOI FinFETs. 相似文献
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Tanoli Shujaat Ali Khan Mustafa Ali Nawaz Faiza Khan Imran Usman Muhammad Khan Zuhaib Ashfaq 《Wireless Networks》2019,25(8):5045-5056
Wireless Networks - This research article presents an innovative approach based on analog network coding (ANC) in conjunction with space time block coding (STBC) which is termed as space time... 相似文献