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961.
Sara J. Palmer Ray L. Frost Godwin Ayoko Tai Nguyen 《Journal of Raman spectroscopy : JRS》2008,39(3):395-401
Raman spectroscopy has been used to characterise synthetic mixed carbonate and molybdate hydrotalcites of formula Mg6Al2(OH)16((CO3)2−,(MoO4)2−)·4H2O. The spectra have been used to assess the molecular assembly of the cations and anions in the hydrotalcite structure. The spectra may be conveniently subdivided into spectral features on the basis of the carbonate anion, the molybdate anion, the hydroxyl units and water units. Bands are assigned to the hydroxyl stretching vibrations of water. Three types of carbonate anions are identified: (1) carbonate hydrogen‐bonded to water in the interlayer, (2) carbonate hydrogen‐bonded to the hydrotalcite hydroxyl surface, (3) free carbonate anions. It is proposed that the water is highly structured in the hydrotalcite, as it is hydrogen bonded to both the carbonate and the hydroxyl surface. The spectra have been used to assess the contamination of carbonate in an open reaction vessel in the synthesis of a molybdate hydrotalcite of formula Mg6Al2(OH)16((CO3)2−, (MoO4)2−)·4H2O. Bands are assigned to carbonate and molybdate anions in the Raman spectra. Importantly, the synthesis of hydrotalcites from solutions containing molybdate provides a mechanism for the removal of this oxy‐anion. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
962.
Razvigor Ossikovski Quang Nguyen Gennaro Picardi Joachim Schreiber Pierre Morin 《Journal of Raman spectroscopy : JRS》2008,39(5):661-672
We present the theory underlying the large numerical aperture objective micro‐Raman backscattering experiment and apply it to the elaboration of a characterization methodology for the determination of the stress tensor in strained cubic semiconductor structures. The presented stress characterization technique consists in monitoring the variations of the stress‐sensitive optical phonon peak position and linewidth while rotating stepwise the sample about its normal. The practical application of the technique is illustrated on a silicon‐on‐insulator (SOI) microelectronic structure demonstrating a plane stress‐tensor determination. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
963.
Nikolai A. Poklonski Nguyen Ngoc Hieu Sergey A. Vyrko Andrei M. Popov 《Physics letters. A》2008,372(35):5706-5711
The dependence of the interwall conductance on distance between walls and relative positions of walls are calculated at the low voltage by Bardeen method for (n,n)@(2n,2n) double-walled carbon nanotubes (DWCNTs) with n=5,6,…,10. The calculations show that interwall conductance does not depend on temperature (for T?500 K) and current-voltage characteristic is linear. The conductance decreases by 6 orders of magnitude when the interwall distance is doubled. Thus, depending on the interwall distance, DWCNTs can be used as temperature stable nanoresistors or nanocapacitors. 相似文献
964.
965.
Thao Quyen Cao Nguyen Viet Phong Jang Hoon Kim Dan Gao Hoang Le Tuan Anh Viet-Duc Ngo Le Ba Vinh Young Sang Koh Seo Young Yang 《Molecules (Basel, Switzerland)》2021,26(15)
The bitter melon, Momordica charantia L., was once an important food and medicinal herb. Various studies have focused on the potential treatment of stomach disease with M. charantia and on its anti-diabetic properties. However, very little is known about the specific compounds responsible for its anti-inflammatory activities. In addition, the in vitro inhibitory effect of M. charantia on pro-inflammatory cytokine production by lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs) has not been reported. Phytochemical investigation of M. charantia fruit led to the isolation of 15 compounds (1−15). Their chemical structures were elucidated spectroscopically (one- and two-dimensional nuclear magnetic resonance) and with electrospray ionization mass spectrometry. The anti-inflammatory effects of the isolated compounds were evaluated by measuring the production of the pro-inflammatory cytokines interleukin IL-6, IL-12 p40, and tumor necrosis factor α (TNF-α) in LPS-stimulated BMDCs. The cucurbitanes were potent inhibitors of the cytokines TNF-α, IL-6, and IL-12 p40, indicating promising anti-inflammatory effects. Based on these studies and in silico simulations, we determined that the ligand likely docked in the receptors. These results suggest that cucurbitanes from M. charantia are potential candidates for treating inflammatory diseases. 相似文献
966.
Nonlinear Dynamics - Based on bifurcation theory, nonlinear frequency response analysis is a recent development in the field of flight dynamics studies. Here, we consider how this method can be... 相似文献
967.
968.
Dang Huyen Vu Xuan Dang Hanh Vu Bich Doan Huu Dung Nguyen Tan Phong 《Research on Chemical Intermediates》2022,48(3):1311-1311
Research on Chemical Intermediates - 相似文献
969.
970.
Dr. Sirinapa Wongwilawan Dr. Doyun Kim Dr. Thien S. Nguyen Wonki Lim Prof. Dr. Sheng Li Prof. Dr. Cafer T. Yavuz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(72):e202202340
Through accumulation, mercury contamination in aquatic systems still poses serious health risks despite the strict regulations on drinking water and industrial discharge. One effective strategy against this is adsorptive removal, in which a suitably functionalized porous material is added to water treatment protocols. Thiol (SH) group-grafted structures perform commendably; however, insufficient attention is paid to the cost, scalability, and reusability or how the arrangement of sulfur atoms could affect the HgII binding strength. We used an inexpensive and scalable porous covalent organic polymer (COP-130) to systematically introduce thiol functional groups with precise chain lengths and sulfur content. Thiol-functionalized COP-130 demonstrates enhanced wettability and excellent HgII uptake of up to 936 mg g−1, with fast kinetics and exceptionally high selectivity. These Hg adsorbents are easily regenerated with HCl and can be used at least six times without loss of capacity even after treatment with strong acid, a rare performance in the domain of Hg-removal research. 相似文献