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1.
M. Hadnadjev-Kostic T. Vulic J. Ranogajec R. Marinkovic-Neducin A. Radosavljevic-Mihajlovic 《Journal of Thermal Analysis and Calorimetry》2013,111(2):1155-1162
The development of nanocomposite photocatalyst based on layered double hydroxides (LDHs) associated with TiO2 was the subject of this research. The thermally activated Zn–Al LDHs were selected as catalyst support precursor because of their proven photocatalytic activity and therefore their possible contribution to overall activity of novel Ti–Zn–Al nanocomposite. The catalyst precursor (Zn–Al LDH) was synthesized by low supersaturation coprecipitation method, and its association with active TiO2 component targeting the formation of novel Ti–Zn–Al nanocomposite was achieved by wet impregnation. Simultaneous thermal analysis (TG–DTA) was used to investigate the thermal behavior of Zn–Al LDH and Ti–Zn–Al LDHs. Complementary, morphology, texture, and structure characterization was carried out. The photocatalytic test reaction was performed under UV light using the methylene blue degradation. The results confirmed a successful impregnation of TiO2 on catalyst support precursor Zn–Al–LDH followed by considerable change in morphology and structure of Zn–Al LDH precursor. It was concluded that the synergic effect between TiO2 and Zn–Al LDH precursor contributes to the overall photocatalytic activity. 相似文献
2.
We discuss the notion of spin squeezing considering two mutually exclusive classes of spin-s states, namely, oriented and non-oriented states. Our analysis shows that the oriented states are not squeezed while non-oriented
states exhibit squeezing. We also present a new scheme for construction of spin-s states using 2s spinors oriented along different axes. Taking the case of s=1, we show that the ‘non-oriented’ nature and hence squeezing arise from the intrinsic quantum correlations that exist among
the spinors in the coupled state. 相似文献
3.
The efficient regioselective and stereospecific synthesis of tetrasubstituted olefins using a mild and convenient method is disclosed. 2-Alkynyl esters are selectively converted to E-beta-chloro-alpha-iodo-alpha,beta-unsaturated esters by exposure to Bu4NI in refluxing dichloroethane. These products are produced cleanly, regio- and stereoselectively, and in high yields. Single-isomer tetrasubstituted olefins bearing four different carbon substituents are then synthesized by sequential palladium-catalyzed coupling reactions. Selectivity results from reactivity differences in the intermediate substrates. 相似文献
4.
The aim of this brief report is to study the behaviour of sheath structure in a multi-component plasma with dust-neutral collisions.
The plasma consists of electrons, ions, micron size negatively charged dust particles and neutrals. The sheath-edge potential
and sheath width are calculated for collisionally dominated sheath. Comparison of collisionless and collisionally dominated
sheath are made. 相似文献
5.
Analysis of a TE011 mode composite sapphire-rutile dielectric resonator has been carried out to study the temperature variation of resonance
frequency, close to the Cs atomic clock hyperfine frequency of 9.192 GHz. The complementary behavior of dielectric permittivity
with temperature of the composite has been exploited to obtain the desired turning point in the resonant frequency. The frequency
of the composite structure is found to be independent of the shield diameter beyond four times the puck diameter. 相似文献
6.
Albert J. B. Loman Leen van der Does Adriaan Bantjes Ivan Vulic 《Journal of polymer science. Part A, Polymer chemistry》1995,33(3):493-504
Results are reported on the effect of lateral methyl groups on the thermal properties of a series of polyesters prepared from diethyl 4,4′-biphenyldicarboxylate and various methyl substituted 1,4-butanediols. The diols were 1,4-butanediol; 2-methyl-1,4-butanediol; 2,2-dimethyl-1,4-butanediol; 2,3-dimethyl-1,4-butanediol; 2,2,3-trimethyl-1,4-butanediol; and 2,2,3,3-tetramethyl-1,4-butanediol. Apart from the tetramethyl derivatve, the transition temperatures of the methyl substituted polyesters were lower with respect of the unsubstituted polyester. On the basis of polarized photomicrographs, a smectic A mesophase was found for the unsubstituted polyester, whereas a nematic mesophase was observed for the 2-methyl substituted polyster. The 2,2-dimethyl, 2,3-dimethyl, and the 2,2,3-trimethyl substituted polyesters showed no liquid crystalline behavior. The 2,2,3,3-tetramethyl derivative displayed a birefringent melt phase although the DSC measurements were not unambiguous. A copolyester based on diethyl 4,4′-biphenyldicarboxylate, 1,4-butanediol, and 2,2,3,3-tetramethyl-1,4-butanediol showed a broad nematic mesophase. Further evidence for the nematic mesophase of this copolyester and the 2-methyl substituted polyester was provided by dynamic rheological experiments. Based on thermogravimetric analysis, it was concluded that the thermal stability was affected only when four methyl side groups were present in the spacer. © 1995 John Wiley & Sons, Inc. 相似文献
7.
V.M.Djinovic L.T. Maneieb G.A. Bogdanovic P.J. Vulie G. del Rosario T.J. Sabo O.B. Milosevie 《光散射学报》2005,17(3):237-239
PureandPt-dopedZnOnanophaseparticles weresynthesizedusingtheultrasonicspraypyrol ysis.Particleswereobtainedthroughdecomposi tionofzincnitrateandnewdevelopedPt(IV) complexwith1,3-propylenediamine-N,N - diacetateligand(pdda)belongingtothetetraden tatecla… 相似文献
8.
Antioxidants can be divided into two broad classes, primary and secondary, depending upon their mode of action. The most broadly used primary antioxidants are hindered phenols. Phenolic antioxidants have traditionally been based on 2,6‐di‐t‐butyl‐4‐methylphenol (BHT). This functional moiety has been incorporated into larger molecules affording products with lower volatility or greater polymer compatibility. More recently, molecules have been introduced which vary in steric hindrance about the phenol and also the way in which multiple phenol functional groups are linked to form larger molecules. This has led to structures which have lower color contribution. Surprisingly, in some cases these molecules have shown higher levels of efficacy relative to other antioxidants with similar phenol/molecular weight ratios. This has included enhanced levels of synergism with secondary antioxidants. An attempt is made to correlate structural features of these molecules to the enhanced performance and/or lower color. 相似文献
9.
Dunn MS Vulic N Shellie RA Whitehead S Morrison P Marriott PJ 《Journal of chromatography. A》2006,1130(1):122-129
Two approaches are described and compared for the analysis of suspected allergens (SAs) in fragrance products, which are defined by the Scientific Committee of Cosmetics and Non-Food Products (SCCNFP). The first consists of a comprehensive two-dimensional gas chromatography (GCxGC) experiment using both a "conventional" non-polar/polar column combination and an "inverse" polar/non-polar column set. The second approach uses a targeted multidimensional gas chromatography (MDGC) system employing a Deans type pneumatic switch and a longitudinally modulated cryogenic system (LMCS). It was found that the conventional and inverse column sets complement each other well, providing identification of SAs present. Compounds well retained on the second dimension of one column set were the first to be eluted from the other. In some instances SAs co-eluting with matrix components on the second dimension for a given column set were clearly resolved on the other, although this has the disadvantage of requiring two analytical runs. Targeted MDGC with a non-polar/polar column set, successfully separated all SAs identified within a fragrance product. The instrument is set up in a similar fashion to a GCxGC system though with longer second dimension ((2)D) column, a cryogenic trap at the beginning of the second column, and a pneumatic switch coupling both columns. The data are easier to process than for a GCxGC experiment. The targeted MDGC method has the capacity to deliver far greater efficiency to targeted regions of a primary separation than a GCxGC experiment, whilst still maintaining overall run times similar to those of a conventional one-dimensional (1D) GC experiment. Cryogenic focussing at the beginning of the (2)D column delivers enhanced sensitivity, accurate (2)D retention times and narrow peak widths; these are responsible for an increased resolution obtained from the fast, relatively short ( approximately 5m) (2)D column. The two column set GCxGC analysis provided a quick and effective means to qualitatively determine the presence of six SAs in a commercially available air freshener, however all were not adequately resolved from matrix components. In contrast, quantitation was straightforward using the targeted MDGC method. 相似文献
10.
Explicit expressions have been derived for the volume dependence of electron-phonon coupling strength (λ) and the Coulomb pseudopotential (μ*) considering the variation of Fermi momentum (κ
F) and Debye temperature (θ
D) with volume. Ashcroft’s model pseudopotential and RPA form of dielectric screening have been used for obtaining pressure
dependence of transition temperature (T
C) and the logarithmic volume derivative (Φ) of the effective interaction strength (N
0
V) for metallic glass superconductor Mg70Zn30. It has been observed that T
C of the metallic glass Mg70Zn30 decreases rapidly with increase of pressure and the superconducting phase disappears at about 30% decrease of volume, for
which the μ* curve shows a minimum and an elbow is formed in the Φ graph. 相似文献