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81.
Azimi Bahareh Maleki Homa Gigante Vito Bagherzadeh Roohollah Mezzetta Andrea Milazzo Mario Guazzelli Lorenzo Cinelli Patrizia Lazzeri Andrea Danti Serena 《Cellulose (London, England)》2022,29(6):3079-3129
Cellulose - Cellulose, a natural, renewable, and environment friendly biopolymer, has been considered as a sustainable feedstock in the near future. However, only 0.3% of cellulose is today... 相似文献
82.
A facile method for the synthesis of various propargylamines derivatives with different structural parts has been reported. The reaction has consisted of one-pot coupling between aldehydes, secondary amines and terminal alkynes using CuCl as a catalyst and choline chloride/urea DES as a cheap and biocompatible reaction media. The procedure is free of using toxic solvents and used CuCl as an available, inexpensive and non-toxic catalyst. Using this methodology, 15 different propargylamine derivatives were successfully synthesized at 60 °C in 15 hr, mostly in good yields. 相似文献
83.
Bahareh Khodashenas Mehdi Ardjmand Mazyar Sharifzadeh Baei Ali Shokuhi Rad Azim Akbarzadeh 《应用有机金属化学》2020,34(6):e5609
In the present study, pectin-coated gold nanoparticles (GNPs) were used as a candidate for curcumin drug delivery. The effect of the size of synthesized GNPs was examined, as an important factor on the yield of drug delivery. For this purpose, three different sizes of GNPs were first synthesized using a chemical method. The synthesized nanoparticles were then coated with pectin biopolymer. Finally, curcumin drug was loaded in a pectin@GNPs complex. Various methods such as UV–vis spectrophotometry, dynamic light scattering, scanning electron microscopy and Fourier-transform infrared spectroscopy were used to characterize the synthesized GNPs and pectin@GNPs. The encapsulation efficiency and the release percentage of the drug were calculated for two different pH values. Further, an antibacterial study was conducted. The results revealed that 100 nm GNPs had the highest encapsulation efficiency. An investigation of the release rate of curcumin drug at 37°C for 48 h indicated that the amount of drug released was higher in acidic pH than at pH 7.4 with a slow release rate. The electronic structure and the adsorption properties of pectin–GNPs complex were examined using the density functional theory method. 相似文献
84.
To reveal the surface elemental composition and chemical states of the Ce1 ? x Eux CrO3 nano‐powders (x= 0.0, 0.3, 0.5, 0.7, 0.8, 1.0), X‐ray photoelectron spectroscopy was carried out in two conditions of before and after surface cleaning. This surface characterization described the core level binding energies of cerium, europium and chromium with different oxidation states. These results verified the morphology of the particles' surface which can be a confirmation of the spin disorder in these core‐shell structures. The effect of surface Ar sputtering on the oxidation states were studied. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
85.
86.
The mathematical formulation and analysis of the Barenblatt–Biot model of elastic deformation and laminar flow in a heterogeneous porous medium is discussed. This describes consolidation processes in a fluid‐saturated double‐diffusion model of fractured rock. The model includes various degenerate cases, such as incompressible constituents or totally fissured components, and it is extended to include boundary conditions arising from partially exposed pores. The quasi‐static initial–boundary problem is shown to have a unique weak solution, and this solution is strong when the data are smoother. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
87.
Hossein Razavi Louis Baker Joseph Hashmall 《Journal of Electron Spectroscopy and Related Phenomena》1985,36(1):29-35
It is shown that the accuracy and precision, and hence the value for bonding-structure studies, in relative binding energy measurements can be enhanced if a common counterion is employed. The differences in chemical shifts between the peaks for the atoms under consideration and for a common counterion in twenty-nine compounds are measured. This technique reduces charging effect errors, which otherwise often occur when non-conducting samples (e.g., salts) are measured relative to a traditional external calibrant. The improvements in accuracy and precision are demonstrated by using the cesium salt of twenty-nine heteropoly and isopoly anions in more than seventy-five different runs. Oxygen 1s, tungsten 4d, and molybdenum 3d binding energies are measured relative to the cesium 3d ionization potential. In this work the cesium counterion is assumed to be chemically invariant. For the relative binding energies that are studied, no dependence on the charge of the anion is observed. A linear relation seems to exist between the oxygen Is binding energies (measured relative to Cs) and the oxygen-to-tungsten ratio in five isopoly anions. This latter finding may serve as a useful aid in studies related to the synthesis of new compounds. 相似文献
88.
The superconducting transition temperature (Tc) of amorphous Nb3Ge was studied under both hydrostatic and quasihydrostatic pressure to 3.5 and 13 GPa, respectively. Whereas hydrostatic pressure causes Tc to initially decrease, Tc is found to increase under higher quasihydrostatic pressures. Tc(p) was also studied on an A-15 crystalline Nb3Ge sample obtained from the amorphous sample by annealing. 相似文献
89.
The pressure dependence of the superconducting transition temperatureT
c
of amorphous La100–x
Al
x
alloys (x=16.5, 20, 25, 30, 34) has been studied under hydrostatic pressure to 3.5 GPa and, additionally, forx=16.5 under quasihydrostatic pressure to 12 GPa. For amorphous samples having Al-concentrationx>20%, T
c
/P is positive in sign and decreases linearly with increasingx, extrapolating atx=0 to the same value (+1.1 K/Gpa) determined for pure crystalline La. For thex=16.5 sample, however, T
c
/P is observed to be anomalously large, more than twice the value expected. The present results are compared with previous studies on amorphous and crystalline La-systems.This paper is dedicated to Prof. Methfessel of this institution on his 60th birthdayThis work is supported by the Minister für Wissenschaft und Forschung des Landes Nordthein-Westfalen 相似文献
90.
Mbindyo JK Mallouk TE Mattzela JB Kratochvilova I Razavi B Jackson TN Mayer TS 《Journal of the American Chemical Society》2002,124(15):4020-4026
Metal nanowires containing in-wire monolayer junctions of 16-mercaptohexanoic acid were made by replication of the pores of 70 nm diameter polycarbonate track etch membranes. Au was electrochemically deposited halfway through the 6 microm long pores and a self-assembled monolayer (SAM) of 16-mercaptohexadecanoic acid was adsorbed on top. A thin layer of Au was then electrolessly grown to form a metal cap separated from the bottom part of the wire by the SAM. Electron micrographs showed that the bottom and top metal segments were separated by an approximately 2 nm thick organic monolayer. Current-voltage measurements of individual nanowires confirmed that the organic monolayer could be contacted electrically on the top and bottom by the metal nanowire segments without introducing electrical short circuits that penetrate the monolayer. The values of the electrical properties for zero-bias resistance, current density, and breakdown field strength were within the ranges expected for a well-ordered alkanethiol SAM of this thickness. 相似文献