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51.
The reaction between Pb and HNO3 has been investigated using the thermometric technique. Weight-loss measurements on the reaction were also obtained. As the HNO3 concentration is increased from 5×10–2 to 4mol l–1, the corrosion rate increases. This is shown thermometrically by a substantial increase in the maximum temperature attained, T
m, as well as a decrease in the time, t, required for reaching T
m. Dissolution of Pb in HNO3 is proposed to take place according to an autocatalytic mechanism. Passivation sets were detected in solutions 11 mol l–1 HNO3. A parallel indication between the thermometric technique and weight-loss measurements was obtained. The rate-determining step of the autocatalytic process involves HNO2 in dissolution of Pb in HNO3. This is supported by the results of addition of hydrazine to the solution. This additive raises the maximum measured temperature, without affecting the corresponding time necessary to reach it. The effect of addition of NaNO2, NaNO3, NaCl, Na2SO4, NaH2PO4 and NaClO4 on the reaction number, RN, of Pb in 4 mol l–1 HNO3 was examined. Only NaNO2 accelerates the dissolution reaction while the other salts show as inhibition effect. It was found that these additives inhibit dissolution due to the displacement of some cathodic depolarizing components, as NO2, from the active sites on the metal surface. The effect of addition of HCl, H2SO4, HClO4 and H3PO4 on the reaction number, RN, of Pb in 4 mol l–1 HNO3 was also investigated. The observed acceleration and retardation of the dissolution of Pb was found to be dependent on both the concentration and nature of anions of the extra acids added. 相似文献
52.
Silicon - An inexpensive spray pyrolysis technique was effectively used to form a p-type SnSb2S4 thin film on n-type Si wafer for the first time to produce SnSb2S4/n-Si heterojunction. The... 相似文献
53.
Abouelnaga Amal M. Meaz Talaat M. Othman Abdelmageed M. Ghazy Riyad A. El Nahrawy Amany M. 《SILICON》2021,13(3):623-631
Silicon - The nature of the opening silicate- based surface affects the chemical interaction, spectroscopic and antimicrobial efficiency. The aim of this approach was to evaluate the spectroscopic... 相似文献
54.
El Nahrawy Amany M. Hemdan Bahaa A. Abou Hammad Ali B. Othman Abdelmageed M. Abouelnaga Amal M. Mansour A. M. 《SILICON》2021,13(9):2979-2991
Silicon - Magnesium calcium silicate nanostructures (MCSNS) loaded with (0.0, 0.6, 0.9, and 1.2 wt%) of Cephradine-drug consisting of mesoporous particles were functionally prepared by sol-gel... 相似文献
55.
56.
Mansour N. Ben Djeridi W. Mir L. El 《Journal of Inorganic and Organometallic Polymers and Materials》2021,31(11):4360-4371
Journal of Inorganic and Organometallic Polymers and Materials - Nanoporous carbon matrix was prepared by the sol–gel process from pyrogallol-formaldehyde (PF) mixtures in water using picric... 相似文献
57.
Smith Robert El. Wekstein David R. Sullivan Robert H. 《IEEE transactions on bio-medical engineering》1970,(2):151-156
A multiplexing, demodulating, and recording telemetry system designed to process multiple pulse-coded temperature channels is described. The system provides complete control of recording and multiplexing sequences and timing, and gives a single analog signal in response to each sample of pulse-coded data. It identifies all channels and indicates to a computer when a new data sample is to be processed. The system is self-calibrating to maintain accuracy over extended data collection periods, and is inexpensive. 相似文献
58.
The properties of styrene/butadiene copolymers obtained by conventional emulsion and miniemulsion polymerizations were studied. Thin layer chromatography with flame ionization detection was used to determine the gel fraction of the copolymer in the latex particles as a function of conversion. It was found that the gel formation began at a higher conversion in the miniemulsion polymerization when compared with that in the conventional process. Also, a lower glass transition temperature was noted at the lowest conversion sampled (~25%), implying a higher initial butadiene monomer concentration within the nucleated miniemulsion monomer droplets when compared with particles formed conventionally. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4616–4622, 2006 相似文献
59.
Cotton and cotton/polyester fabrics were treated against microbial attack by applying a formulation based essentially on ZnO under high‐energy radiation and thermal curing. To achieve the homogeneity and the reactivity of the treating formulation, a binder (Impron MTP) and a dispersing agent (Setamol WS) were used with ZnO. The antimicrobial property of the fabrics was evaluated, in terms of mechanical properties, by a soil burial test. Moreover, the effect of antimicrobial finishing on the dyeing properties in terms of color strength was investigated. It was found that the best composition that affords the best antimicrobial protection to cotton fabrics contains 2% ZnO, 2% binder, and 1% dispersing agents. For the cotton/polyester blend, the best results were achieved at the same conditions except the ZnO was 1%. It was found that the treatment under the effect of electron‐beam irradiation is better than that of gamma irradiation and thermal curing. The results showed that when the finishing process was carried out before dyeing with a reactive dye, it affects the color strength rather than performing the finishing after the dyeing process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1129–1137, 2003 相似文献
60.
Ghurmallah H. Al‐Ghamdi E. David Sudol Victoria L. Dimonie Mohamed S. El‐Aasser 《应用聚合物科学杂志》2006,101(6):4504-4516
Miniemulsification technology was used to encapsulate TiO2 particles inside a styrene/n‐butyl acrylate copolymer with high loading levels (11 to 70% PVC (pigment volume concentration)). In this approach, a St/BA copolymer dissolved in toluene in the presence of a costabilizer (hexadecane) was mixed with a dispersion of TiO2 particles in toluene and sonified, and then emulsified in an aqueous surfactant solution by sonification. The effect of sonification time on both the dispersibility of the TiO2 particles in the presence of the copolymer and hexadecane and on the encapsulated particle size was investigated. Particle size analysis by dynamic light scattering showed that these composite latexes are quite stable. It was also found that as the TiO2 loading increased from 11 to 43% PVC, the particle size of the TiO2 dispersion decreased while the polymer‐encapsulated TiO2 particle size increased. The effect of surfactant concentration (sodium lauryl sulfate, SLS) on the encapsulated particle size was investigated using four different SLS concentrations in the 11% PVC system. The results showed that as the SLS concentration increased the particle size decreased, as expected. Also it was found that the minimum surfactant concentration that gives stable encapsulated TiO2 particles is above 10 mM SLS. The role of HD in the recipe was studied for an artificial latex containing no TiO2 and one prepared at 11% PVC, in terms of particle size before and after solvent stripping, and its effect on the Tg. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4504–4516, 2006 相似文献