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排序方式: 共有1111条查询结果,搜索用时 31 毫秒
31.
Hossein Eshghi Zinat Gordi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1553-1557
Abstract A facile and efficient method for the preparation of Z-aldoximes is improved by means of P2O5/SiO2 reagent in solvent-free media. Advantages of this method are the use of inexpensive and selective reagent, with high yields in simple operation, and short reaction time under solvent-free conditions. 相似文献
32.
K. Uhlig 《Isotopes in environmental and health studies》2013,49(2):37-42
0. Einleitwng 1. Reaktorwissenschaft und -technik und Kernenergetik 2. Kerntechnischer Gerätebau 3. Produktion von Isotopenerzeugnissen 4. Strahlenschulz und Schutztechnik 5. Isotopenanwendung 6. Strahlentechnik 7. Zur weiteren Tätigkeit der Ständigen Kommission Atomenergie des RGW 相似文献
33.
实验研究了基于以钢丝绳为基本元件的新型柔性防撞装置的防护性能.利用DEWETRON数据采集仪及多通道同步采集传感器的信号,分析得到防撞装置在碰撞中受到的撞击力曲线.实验结果显示:靠近船舶撞击侧最近的非撞击侧位置受到的撞击力最大,属防护重点部位;在承受多次撞击后,防撞装置基本完好,且船舶在碰撞中的损伤也有所减低. 相似文献
34.
Nobuhiro Takeda Norihiro Tokitoh Renji Okazaki 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):633-636
The first rotational isomers of stable selenoaldehydes are synthesized by deselenation of cyclic polyselenides having an efficient steric protection group, 2, 4, 6-tris[bis(trimetylsilyl)methyl]phenyl (Tbt). Reactions of these selenoaldehydes with W(CO)5.THF gives the corresponding η1-selenoaldehyde tungsten complexes, the structures of which are established by X-ray crystallography. 相似文献
35.
AbstractChemically functionalized graphene oxide [multi-amino functionalized graphene oxide (MAGO)] was achieved by building covalent bonds between graphene oxide (GO) and a small molecule containing benzene structure and multi-amino groups. Fourier transform infrared, X-ray diffraction, X-ray photo electron spectroscopy and TEM-EDX results certified that the molecule was successfully grafted onto GO nanosheets. Subsequently, functionalized GO was incorporated into waterborne epoxy (EP) coating through ball-milling method. This molecular design can significantly improve the dispersion of MAGO in EP matrix, as well as the compatibility and interaction between MAGO and EP. Compared with GO/EP, the water absorption of MAGO/EP decreased from 4.38 to 2.59%, the adhesion strength of MAGO/EP increased from 4.72 to 6.32?MPa after immersion of 40?days in 3.5% NaCl solution. Incorporation of 1?wt% of MAGO into EP matrix prominently improved the long-term corrosion resistance. The impedance modulus of GO/EP coating decreased by four orders after 40 days immersion, while that of MAGO/EP coating only decreased by one order. The impedance modulus was still 1.47?×?108 Ω cm2, and two-time constant wasn’t detected for MAGO/EP coating. This research developed a novel green anticorrosion coating with enhanced durability for metal protection. 相似文献
36.
1-C-(4,6-O-Benzylidene-β-D-glucopyranosyl) acetone has been studied in a catalytic system consisting of triethylamine-p-dimethylaminopyridine (TEA-DMAP) in the presence of a number of esterification reagents in dichloromethane. It was found that all-protected and monoprotected products form simultaneously. However, the regioselectivity tends to favor the 3-substituted derivative. Structural parameters have been determined by 1H NMR, 13C NMR, 1H-1H correlation spectroscopy, and elemental analysis. Furthermore, a possible mechanism for the formation of intramolecular hydrogen-bond networks between the carbonyl group and 2-OH was described. The energy changes of the transition state in this reaction, as determined by a molecular modelling study, provided further evidence to assign the relative reactivities of each individual hydroxyl group. 相似文献
37.
Ellman's dihydropyran resin was used for selective protection of monosaccharide thioglycosides and glycosides. Following on‐resin acylation and subsequent cleavage of the polymer‐bound intermediates, product components having selectively unblocked hydroxyl functions could be obtained. 相似文献
38.
39.
Gustavo Pereira Saito Ana Carolina Lanfredi Matsumoto Renata Pires Assis Iguatemy Loureno Brunetti Marco Aurlio Cebim Marian Rosaly Davolos 《Molecules (Basel, Switzerland)》2021,26(8)
Excessive UV solar radiation exposure causes human health risks; therefore, the study of multifunctional filters is important to skin UV protective ability and also to other beneficial activities to the human organism, such as reduction of reactive oxygen species (ROS) responsible for cellular damages. Potential multifunctional filters were obtained by intercalating of ferulate anions into layered simple metal hydroxides (LSH) through anion exchange and precipitation at constant pH methods. Ultrasound treatment was used in order to investigate the structural changes in LSH-ferulate materials. Structural and spectroscopic analyses show the formation of layered materials composed by a mixture of LSH intercalated with ferulate anions, where carboxylate groups of ferulate species interact with LSH layers. UV-VIS absorption spectra and in vitro SPF measurements indicate that LSH-ferulate systems have UV shielding capacity, mainly UVB protection. The results of reactive species assays show the ability of layered compounds in capture DPPH•, ABTS•+, ROO•, and HOCl/OCl− reactive species. LSH-ferulate materials exhibit antioxidant activity and singular optical properties that enable their use as multifunctional filters. 相似文献
40.
Young Her Tae-Kyeong Lee Ji Hyeon Ahn Soon Sung Lim Beom-Goo Kang Jung-Seok Park Bora Kim Hyejin Sim Jae-Chul Lee Hyun Sook Kim Tae Heung Sim Hyun Sam Lee Moo-Ho Won 《Molecules (Basel, Switzerland)》2021,26(1)
Since ancient times, various herbs have been used in Asia, including Korea, China, and Japan, for wound healing and antiaging of the skin. In this study, we manufactured and chemically analyzed a novel distillate obtained from a fermented mixture of nine anti-inflammatory herbs (Angelica gigas, Lonicera japonica, Dictamnus dasycarpus Turcz., D. opposita Thunb., Ulmus davidiana var. japonica, Hordeum vulgare var. hexastichon Aschers., Xanthium strumarium L., Cnidium officinale, and Houttuynia cordata Thunb.). The fermentation of natural plants possesses beneficial effects in living systems. These activities are attributed to the chemical conversion of the parent plants to functional constituents which show more potent biological activities. In our current study, the distillate has been manufactured after fermenting the nine oriental medical plants with Lactobacillus fermentum, followed by distilling. We analyzed the chemical ingredients involved in the distillate and evaluated the effects of topical application of the distillate on ultraviolet B (UVB)-induced skin damage in Institute of Cancer Research (ICR) mice. Topical application of the distillate significantly ameliorated the macroscopic and microscopic morphology of the dorsal skin against photodamage induced by UVB radiation. Additionally, our current results showed that topical application of the distillate alleviated collagen disruption and reduced levels of proinflammatory cytokines (tumor necrosis factor alpha and interleukin 1 β expressions) in the dorsal skin against UVB radiation. Taken together, our current findings suggest that the distillate has a potential to be used as a material to develop a photoprotective adjuvant. 相似文献