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排序方式: 共有618条查询结果,搜索用时 27 毫秒
31.
Phillip Masimba Toperesu Girish M. Kale Jafar Daji David E. Parkinson Simon Parkinson 《International Journal of Applied Ceramic Technology》2022,19(2):1160-1170
The corrosion behavior of a tin IV oxide-doped AZS-refractory, subject to static and dynamic corrosion testing at 1370˚C in soda-lime-silica glass, was studied considering the effect of the microstructural features on corrosion. The refractory was synthesized by slip cast methods through reaction sintering of alumina and zircon raw materials using SnO2 as a sintering agent. SnO2 had a considerable influence in the enhanced alumina/zircon reaction sintering and the subsequently evolved microstructures of an interlocked Zr(1-x)Sn(x)O2 solid solution reinforced alumina-mullite composite. The process kinetics of the refractory corrosion followed reasonably well the predicted dependence on the square root of angular velocity under forced convection corrosion. Glass chemical corrosion and erosion of the refractory, under static and dynamic glass conditions, respectively, revealed the Zr(1-x)Sn(x)O2 solid solution-rich mullite matrix as providing the most corrosion resistance and glass compatibility. 相似文献
32.
Vijay Kale R. Subbarao G. Lakshminarayana M. Bhagwant Rao 《Journal of the American Oil Chemists' Society》1991,68(8):583-584
C36 Dimer acids were esterified with various short-chain alcohols, namely 2-propanol, n-butanol, n-hexanol, n-octanol, 2-octanol
and 2-ethyl-1-hexanol by using sulfuric acid as catalyst and benzene as an azeotropic solvent. Various reaction parameters
were standardized. In case of isopropyl esters, acid-to-alcohol mole ratio of 1:5 and sulfuric acid concentration of 2% based
on the weight of dimer acids were found to be optimum. In case of straight-chain primary alcohols, namely n-butanol, n-hexanol
and n-octanol, 1:2.5 mole ratio of acid to alcohol and 1% by weight of sulfuric acid were found satisfactory. Esterification
reaction rates were determined from the fall in acid value of the product. The reaction followed pseudo first order kinetics.
The reaction rates increased with the increase in chainlength of straight-chain primary alcohols from n-butanol to n-octanol.
The rate of reaction decreased from n-octanol to 2-ethyl-1-hexanol to 2-octanol due to the branching of the chain in 2-ethyl-1-hexanol
and secondary nature of the −OH group in 2-octanol. 相似文献
33.
Mechanism of MxOy nanoparticles/CNTs for catalytic carbonization of polyethylene and application to flame retardancy
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Karolina Wenelska Xuecheng Chen Beata Zielinska Ryszard J. Kaleńczuk Paul K. Chu Tao Tang Ewa Mijowska 《应用聚合物科学杂志》2017,134(34)
Three kinds of metal oxide nanoparticles (Fe3O4, Co3O4, and Ni2O3) are produced on carbon nanotubes (CNTs). The synergistic effects rendered by the CNTs and metal oxide nanoparticles on carbonization of polyethylene (PE) are studied and applications to flame retardancy of PE are investigated systematically. The CNT‐Ni2O3 delivers the best performance and the mechanism pertaining to the enhanced flame retardancy is proposed and discussed. It is found that under the same conditions, the carbonization rate can be a factor to influence the flame retardancy performance. Among Fe, Co, and Ni, Ni has the fastest carbonation rate, which leads to the best flame retardancy performance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45233. 相似文献
34.
Polyester (PET) nanocomposite fibers were spun by adding master batches of linear low‐density polyethylene (LLDPE) loaded with Montmorillonite (MMT) nanoclay after compatibilizing the PET and LLDPE. The spun fibers showed increased thermal stability as well as flame retardancy, which increased progressively with the amount of nanoclay loaded into the fiber. There is slight decrease in tensile strength of the fiber accompanied by decrease in elongation % indicating addition of nanoclay makes the filaments stiffer. The onset of crystallization temperature occurred at higher temperature in case of composite fibers than on the neat PET fiber because of nucleating effect of nanoclay. The dyeability of the fibers was not affected and also had very little impact on the flame retardancy of the fiber. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers 相似文献
35.
Histogram equalization is the common method used for contrast enhancement. The mean brightness of the image is adjusted to middle of the permitted range and hence is not suitable for consumer electronics products. A novel contrast enhancement method using modified octagon histogram equalization is developed to overcome the drawback of conventional technique for gray scale images. The proposed algorithm is applied for boat image, microstructure of steel and human head. The contrast enhanced out of the images mentioned is obtained, and the efficiency of the algorithm is evaluated. Simulation results shows that the proposed method can enhance the different types of images effectively. Besides, the proposed contrast enhancement method using modified octagon histogram equalization has comparable performance with black and white stretching and adaptive histogram equalization. 相似文献
36.
Ercan Varol Selahattin Akcay Banu Kale Koroglu 《The Science of the total environment》2010,408(11):2295-2298
Sixty three patients with endemic fluorosis (36 males/27 females; mean age 33.9 ± 8.6 years) and 45 age, sex and body mass index (BMI) matched healthy controls (30 males/15 females; mean age 32.7 ± 8.8 years) were included in this study. Basic echocardiographic measurements, left ventricular diastolic parameters and left ventricular myocardial performance index (MPI) were measured. The left ventricular MPI was calculated as (isovolumic contraction time + isovolumic relaxation time) / aortic ejection time by Doppler. The urine fluoride levels of fluorosis patients were significantly higher than control subjects as expected (1.9 ± 0.1 mg/l vs 0.4 ± 0.1 mg/l respectively; P < 0.001). Isovolumic relaxation time (IVRT) and deceleration time (DT) were significantly higher in fluorosis patients than in controls (for IVRT 106.9 ± 15.6 ms vs 96.7 ± 12.2 ms; P < 0.001 and for DT 211.7 ± 30.7 ms vs 188.0 ± 30.0 ms; P < 0.001, respectively). MPI was significantly higher in fluorosis patients than in controls (0.62 ± 0.15 ms vs 0.49 ± 0.10 ms; P < 0.001, respectively). We have shown that chronic fluorosis patients had left ventricular diastolic and global dysfunctions. 相似文献
37.
Havva Kazdal Zeytin Hakan Yildirim Banu Berme Selim Duduolu Gürkan Kazdal Adem Deniz 《钢铁研究学报(英文版)》2011,18(11):31-39
Heat treatment methods were applied to white cast iron for improving the impact and wear resistance. Additionally, chemical composition optimization was made. Furthermore, the effect of boron addition on such applications was investigated. Samples were investigated by using optical and electron microscope methods. Hardness, wear and impact tests were conducted. The results showed that the secondary carbides in the standard alloy were iron-enriched, needle-like carbides M3C when the boron-added alloy contained Fe23(C,B)6 type, globular secondary carbides. It was concluded that heat treatment B provided higher wear and hardness properties, compared to the standard heat treatment. Optimum mechanical properties were obtained by lower destabilisation temperatures and increasing temperature reduced the wear resistance and hardness. 相似文献
38.
Dafone inhibits the lipid peroxidation significantly in a concentration dependent manner. The inhibition was found to be an uncompetitive type with the inhibition constant (Ki) of 62.5muM On the other hand complexation with metal ions results in a significant reversal from antioxidant to pro-oxidant properties for the resulting complexes which are cationic and with associated halometallate anions. The nature of the potentiation in case of the ferric compound was of competitive type with activation constant (Ka) having the value 32.5muM. The neutral copper-dafonate complex, however, inhibits lipid peroxidation with increase in concentration. 相似文献
39.
Arias J. Kiss P. Prodanov V. Boccuzzi V. Banu M. Bisbal D. Pablo J.S. Quintanilla L. Barbolla J. 《Solid-State Circuits, IEEE Journal of》2006,41(2):339-351
We present an experimental continuous-time complex delta-sigma multi-bit modulator, implemented in standard 0.25-/spl mu/m CMOS technology and meeting all major requirements for application in IEEE 802.11a/b/g wireless LAN receivers. The clock frequency is 320 MHz, producing an oversampling ratio of 16 for 20 MHz channel bandwidths. The modulator supports two operation modes for zero-IF and low-IF receiver architectures respectively, requires a single 2.5-V power supply, and dissipates only 32 mW of power. The measured peak signal-to-noise ratio is 55 dB. Further experimental results using sine-wave and OFDM test signals are also presented. 相似文献
40.
Vibration characteristics of an elastic plate in the shape of an infinite strip are changed by applying a lateral concentrated
force to the plate. The homogeneous, isotropic, elastic plate is infinite in the x-direction and the sides are simply supported. The size of the force is changed in proportion to the displacement measured
at a certain point of the plate. The proportionality constant serves as the control parameter. The mathematical formulation
of this distributed control problem and its analytical solution in terms of the vibration frequencies of the plate are given.
The vibration frequencies are plotted as a function of the control parameter. 相似文献