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61.
Ram Prakash R.J. Choudhary D.M. Phase 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2008,266(8):1242-1246
Thin films of Fe3O4 have been deposited on single crystal MgO(1 0 0) and Si(1 0 0) substrates using pulsed laser deposition. Films grown on MgO substrate are epitaxial with c-axis orientation whereas, films on Si substrate are highly 〈1 1 1〉 oriented. Film thicknesses are 150 nm. These films have been irradiated with 200 MeV Ag ions. We study the effect of the irradiation on structural and electrical transport properties of these films. The fluence value of irradiation has been varied in the range of 5 × 1010 ions/cm2 to 1 × 1012 ions/cm2. We compare the irradiation induced modifications on various physical properties between the c-axis oriented epitaxial film and non epitaxial but 〈1 1 1〉 oriented film. The pristine film on Si substrate shows Verwey transition (TV) close to 125 K, which is higher than generally observed in single crystals (121 K). After the irradiation with the 5 × 1010 ions/cm2 fluence value, TV shifts to 122 K, closer to the single crystal value. However, with the higher fluence (1 × 1012 ions/cm2) irradiation, TV again shifts to 125 K. 相似文献
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63.
INTRODUCTION AND OBJECTIVE: From the multimedia technology and of the digital recording of the voice, we have redesigned the verbal dichotic listening test. The recognition of 15 monosyllabic word pairs offered though some earphones is presented in an interactive program. METHODS: Using the mouse button, the subject decides the moment in which each stimuli coupe will take place. Likewise, the screen displays 10 words, among which you have to recognize the words supplied by the earphones. Finally, the program results in complete right answers and right answers cross or referred to the opposite ear. RESULTS: Applied the test to a sample of 92 subjects, apparently normal, with a middle and high cultural level, from among 19 and 60 years (44 females and 48 males), the test resulted in a predominance of rights answers in the right ear (p < 0.0064). Separated the sample in in left-handed and right-handed men (67 right handed and 25 left-handed), it hasn't been found meaningful differences among their averages. Separated the sample by sex, the differences among the slightly meaningful averages (p < 0.04, according to the Student's t test). CONCLUSIONS: The test is offered as a resource appropriate for laterality studies, and for differential disorder study of gnosias and praxias of the dyslexias of aphasias, hearing aids, multiple sclerosis, and aptitudes studies. 相似文献
64.
The effects of air oxidation of three Spanish coals on the pressure exerted during carbonization have been studied. Coals were oxidized by air in an oven at 120 and 140 °C. The extent of oxidation was assessed by the Audibert-Arnu dilatometer test. Coal samples oxidized at different levels were subjected to the Koppers-lncar laboratory coking pressure test. The results obtained indicated that for coals classified as ‘dangerous’ the ‘danger’ increased and reached a maximum at a certain level of oxidation, after which it decreased sharply. This behaviour did not occur with coals classified as safe. 相似文献
65.
Valerio Choque Pilar Ramírez de la Piscina Daniel Molyneux Narcís Homs 《Catalysis Today》2010,149(3-4):248-253
The partial oxidation of methane is studied at 673–873 K over new Ru-based catalysts supported on TiO2–ZrO2 with different TiO2 content. Supports were prepared by a sol–gel method, and RuCl3 and RuNO(NO3)3 were used as ruthenium precursors to prepare the catalysts (1–2 wt% Ru). The effect of the reaction temperature on the catalytic behavior is analyzed, along with the support composition and the Ru precursor used. 相似文献
66.
P. Ramírez de la Piscina J. L. G. Fierro G. Muller J. Sales N. Homs 《Catalysis Letters》1992,14(1):45-49
New heterogenized Pt/Sn catalysts selective for the hydroformylation of 1-pentene have been synthesized. The complex cis-[PtCl2(PPh3)2] and the SnCl2.2H2O or SnC2O4 precursors have been anchored on silica-, magnesia- and alumina-carriers. X-ray photoelectron spectroscopy was used to determine the surface composition and the nature of the anchored species. The hydroformylation activity was found to depend on the type of support and tin precursor used. Only the silica supported catalysts were active in the hydroformylation reaction. Samples prepared from SnCl2-2H2O were 200-fold more active than those prepared from SnC2O4. Selectivity ton-hexanal of the silica-supported catalyst prepared from SnCl2-2H2O was as high as 94.4% at 39.2% conversion of 1-pentene. 相似文献
67.
A series of N‐isopropylacrylamide/[[3‐(methacryloylamino)propyl]dimethy(3‐sulfopropyl)ammonium hydroxide] (NIPAAm/MPSA) copolymer hydrogels were prepared with various compositions. Swelling of the hydrogels in water, aqueous NaCl, KCl, CaCl2, and MgCl2 solutions was studied. NIPAAm/MPSA hydrogels have a higher degree of swelling in water and salt solutions than that of poly(N‐isopropylacrylamide) (PNIPAAm). Also, NIPAAm/MPSA hydrogels are more salt resistant when deswelling in salt solutions. For <7 mol % MPSA, the formed hydrogels retain both temperature reversibility and high swelling. A higher content of MPSA (>11 mol %) leads to better salt resistance but a decrease in thermosensitivity. The swelling of NIPAAm/MPSA hydrogel in 0.05M NaCl is non‐Fickian. In NaCl and KCl aqueous solutions, the zwitterionic hydrogels do not show obvious antipolyelectrolyte swelling behavior, whereas in divalent salt CaCl2 and MgCl2 solutions, the swelling ability of NIPAAm/MPSA hydrogels is enhanced at low salt concentration, then decreases with further increase in salt concentration. The lower critical solution temperatures of NIPAAm/MPSA hydrogels are also affected by concentrated salt solution. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2032–2037, 2003 相似文献
68.
Biswajit Samir De Ram Ji Dixit Abhas Anand Vicky Rahul Dhongde Suddhasatwa Basu 《加拿大化工杂志》2023,101(6):3167-3179
Electrochemical conversion of biomass to value-added chemicals has gained impetus in recent years. Herein, we present a methodology for recovering biomass-derived 2-furoic acid from the dilute aqueous stream by reactive extraction. The reactive extraction was performed using a chemical extractant, trioctylamine (TOA), with diluents (octanol, chloroform, and diethyl ether). Equilibrium parameters influencing the recovery of 2-furoic acid were evaluated. Using TOA in various diluents, the 2-furoic acid was recovered with 85%–99% efficiency. A 1:1 complex of the 2-furoic acid—TOA was formed in the organic phase, and the experimental equilibrium complexation constant was compared with that obtained from the relative basicity and Langmuir models. The equilibrium parameters were used for column design to estimate the solvent to feed ratio (S/F) and the number of theoretical stages (NTS). The NTS required is 12 to attain 99% recovery of 2-furoic acid in counter-current extraction. The present study sheds light on the reactive extraction process adopted for process intensification with electrochemical conversion, paving the way for the commercialization of valuable products obtained from biomass. 相似文献
69.
70.
The simulation model of a transcritical CO2 heat pump dryer presented in Part 1 has been first validated with available experimental data in this part and then used to simulate the heat pump dryer to study the variation of performance parameters such as heating COP, moisture extraction rate, and specific moisture extraction rate. The validation with experimental data shows that the model slightly over predicts the system performance. The possible reasons for the difference between experimental and numerical results are explained. Simulation results show the effect of key operating parameters such as bypass air ratio, re-circulation air ratio, dryer efficiency, ambient condition (temperature and relative humidity), and air mass flow rate. Results show that unlike bypass air ratio and ambient relative humidity, the effect of dryer efficiency, recirculation air ratio, ambient temperature, and air mass flow rate are very significant as far as the system performance is concerned. 相似文献