Supramolecular gels are one kind of important soft material, in which small low-molecular weight compounds self-assemble into various nanostructures through non-covalent interactions to immobilize the solvents. While there are many important fundamental issues related to the gelation process, such as the design of the gelator, synergism of various non-covalent interactions between gelators, gelator-solvents, the balances between gelation and crystallization and so on, the self-assembled nanostructures forming during gelation are very interesting. These nanostructures have many unique features, such as the flexibility to respond to external stimuli, morphological diversity, ease of fabrication in large quantities, and so on. This review highlights some important features in tuning the nanostructures in the supramolecular gels from their morphological diversity, morphology control, morphology conversion, and morphology-depended functions.
Chapter 1: Atoms, Molecules, Electrons, Light and Heat in Nanometre Confinement Chapter 2: Organic Carbon Chapter 3: Main Group Elements Chapter 4: Iron Chapter 5: Transition Metals Subject Index
The speed of high-speed permanent magnet motor has always been restricted by the strength of the rotor. Therefore, this paper proposes a type of magnetic composite rotor suitable for high-speed permanent magnet motors, which can fundamentally solve the problem that it is easy to cause damage for permanent magnets in high speed. In this paper, a combination of theoretical calculation, numerical simulation and experimental verification are used for the magnetic composite material. Based on the theoretical model of the composite micromechanics rule of mixture method, the mechanical properties of the three-phase magnetic composite material are successively deduced. The calculation model of magnetic composite material was compared by using the finite element method and the analytical method, the experimental result was used to verify the correctness of the calculation results. Finally, the influence of carbon fiber thickness and magnetic powder content on the mechanical properties of the material was studied.
A two-step self-assembly procedure on smooth, aminated silica particles established holey monolayers. At first, single, flat-lying porphyrin tetraamides (A) were bound covalently, followed by the build-up of a rigid monolayer made of diamido bolaamphiphiles (bolas) around the porphyrin islands. "Nanowells" around porphyrin (A) bottoms with a uniform diameter of 2.2 nm and varying depths of 0.6, 1.0, or 1.5 nm depending on the length of the applied bolas were thus obtained. Oligoethylene headgroups solubilized the particles in water, ethanol, and chloroform/ethanol, and two hydrogen bond chains between the secondary amide groups prevented swelling of the monolayer. Manganese(III) porphyrinates (B) migrated from the bulk solution to the bottom of the form-stable nanowells with a speed of about 1 pm/s and were trapped there above porphyrin (A). After isolation of the (A,B) particles by centrifugation or ultrafiltration, the particles were suspended in a chloroform solution of a chlorin (C), which was also fixated irreversibly on the bottom of the nanowells. The nanowells thus contained three different porphyrins A,B,C in a noncovalent stack. The reverse sequence A,C,B was built-up correspondingly, first in chloroform/ethanol, and then in water. The "sorting" of A,B,C and A,C,B systems was characterized by visible spectra, sequence-dependent fluorescence quenching, and cyclic voltammetry of the top component. The molecular sorting method is the first of its kind and should be generally useful for the production of noncovalent reaction systems on any smooth surface.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
To transfer high free fatty acid oil into biodiesel in mild conditions is still facing challenge, thereinto, the key is efficient acid catalyst. In this study, 2,5–dimercaptoterephthalic acid was adopted to substitute terephthalic acid as ligand for UiO–66–(SH)2 synthesis, then the sulfydryl (–SH) was in-situ oxidized by hydrogen peroxide and acidified via sulfuric acid thus generating sulfonic catalyst UiO–66–(SO3H)2. To further reveal the relationship between physico–chemical property and catalytic activity, catalyst was characterized via thermogravimetry analysis (TG), X–ray diffraction (XRD), N2 absorption–desorption, scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and pyridine absorption–Fourier transform infrared spectroscopy (Py–FTIR). Results indicate the in–situ modification increases the quantity of acid sites for UiO–66(Zr), where the acidity is aggrandized from 0.02 mmol/g to 2.28 mmol/g. The maximum conversion of oleic acid to biodiesel was 86.52% with catalyst amount of 10 wt.% and molar ratio of methanol/oleic acid of 15 at 90 ℃ within 4 h. Moreover, UiO–66–(SO3H)2 exhibited favorable reusability and water resistance, which maintained an excellent esterification conversion after four cycles and no obvious impact was detected as the water content was 10 wt.%. The quality of obtained biodiesel in this study satisfied the European Union standard of EN 14214, which could be used as transport fuel.
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