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41.
A cylindrical capsule containing a coiled alkane incorporates spacers. The alkane lengthens and gauche strain is relieved. The spacer can be removed to reset the system to the original state. The system represents a spring-loaded device that operates reversibly in response to acids and bases. 相似文献
42.
An even factor of a graph is a spanning subgraph in which each vertex has a positive even degree. Let G be a bridgeless simple graph with minimum degree at least 3. Jackson and Yoshimoto (2007) showed that G has an even factor containing two arbitrary prescribed edges. They also proved that G has an even factor in which each component has order at least four. Moreover, Xiong, Lu and Han (2009) showed that for each pair of edges e1 and e2 of G, there is an even factor containing e1 and e2 in which each component containing neither e1 nor e2 has order at least four. In this paper we improve this result and prove that G has an even factor containing e1 and e2 such that each component has order at least four. 相似文献
43.
Augusto Marcelli Wei Xu Dariush Hampai Luca Malfatti Plinio Innocenzi Ulrich Schade Ziyu Wu 《Analytical and bioanalytical chemistry》2010,397(6):2095-2108
Many physical/chemical processes such as metal–insulator transitions or self-assembly phenomena involve correlated changes
of electronic and atomic structure in a wide time range from microseconds to minutes. To investigate these dynamic processes
we not only need a highly brilliant photon source in order to achieve high spatial and time resolution but new experimental
methods have to be implemented. Here we present a new optical layout for performing simultaneous or concurrent infrared and
X-ray measurements. This approach may indeed return unique information for example the interplay between structural changes
and chemical processes occurring in the investigated sample. A beamline combining two X-ray and IR beams may really take advantage
of the unique synchrotron radiation properties: the high brilliance and the broad spectrum. In this contribution we will describe
the conceptual layout and the expected performance of a complex system designed to collect IR and X-ray radiation from the
same bending magnet on a third-generation synchrotron radiation ring. If realized, this beamline will enable time-resolved
spectroscopy experiments offering new scientific opportunities at the frontiers of science. 相似文献
44.
Dariush Saberi Hajar Hashemi Niloofar Ghanaatzadeh Majid Moghadam Khodabakhsh Niknam 《应用有机金属化学》2020,34(4):e5563
A new ruthenium/dendrimer complex stabilized on the surface of silica-functionalized nano-magnetite was fabricated and well characterized. The nano-catalyst showed good activity in the synthesis of benzil derivatives via the oxidation of stilbenes with high turnover frequency (TOF) at room temperature. Moreover, the catalyst could also be reused up to fifteen times without any loss of its activity. 相似文献
45.
46.
Effect of high electric field on the dc conductivity of TeO2-V2O5-MoO3 amorphous bulk samples with different molar ratio of each component was investigated with gap-type electrode arrangement.
At low electric fields, the current-voltage (I–V) characteristics has a linear shape, while at high electric fields (>103 V/cm), bulk samples show nonlinear behavior (nonohmic conduction) and current-voltage characteristics shows increasing deviation
from Ohm’s law with increasing current density. High-field effect of Pool-Frenkel type was observed at electrical fields about
103−104 V/cm. In addition, positive deviation from Pool-Frenkel effect was observed when a field higher than about 104 V/cm was applied. 相似文献
47.
Gas phase catalytic oxidation of ethyl acetate and toluene was examined over copper modified ZSM‐5 catalysts under atmospheric pressure. Nanostructure of ZSM‐5 was characterized by XRD, SEM and TEM techniques. Elemental composition of ZSM‐5 was determined using EDX, ICP‐AES and XPS techniques. Results of catalytic studies showed better catalytic activity of Cu‐ZSM‐5 catalysts than those of parent ZSM‐5 and HZSM‐5, which revealed catalytic role of copper ions in the Cu‐ZSM‐5 catalysts. Effects of some parameters over catalytic conversion of these compounds were also studied. Ethyl acetate showed more reactivity than toluene over the Cu‐ZSM‐5 catalysts. Furthermore, the catalytic activity of Cu‐ZSM‐5 catalysts increased with increasing the copper loadings. The conversion behavior of a binary mixture of ethyl acetate and toluene was different from that of a single form. A promotive and inhibitive behavior was observed for conversion of ethyl acetate and toluene in the binary mixture, respectively. Water vapor as co‐feed had an inhibitive effect on conversion of organic compounds over the Cu‐ZSM‐5 catalysts. 相似文献
48.
Dariush?Hinderberger Gunnar?Jeschke Hans-Wolfgang?SpiessEmail author 《Colloid and polymer science》2004,282(8):901-909
The network-forming ability of a small fraction of nanosized trianions of the triarylmethyl class (TAM) with poly(diallyldimethylammonium chloride) (PDADMAC) polyelectrolyte is studied by high-field/high-frequency (94 GHz) electron paramagnetic resonance spectroscopy. These tristar-shaped organic ions are expected to undergo both electrostatic and hydrophobic interactions with PDADMAC chains. The dependence of electron spin echo (ESE)-detected spectra of the TAM spin probe on PDADMAC concentration reveals a heterogeneous distribution of the spin-carrying counterions. One fraction of these ions forms densely packed clusters while another one is highly diluted. On varying the concentration ratio of TAM spin probe/PDADMAC, the mean distance between closest neighbors within clusters of approximately 1.5 nm does not change significantly, while their fraction increases with decreasing polyelectrolyte content. These findings indicate that the nanosized organic TAM trianions induce network formation in solutions of PDADMAC polyelectrolyte. The data are consistent with a zip-like cooperative binding effect of TAM ions, making this spin probe an interesting building block for electrostatic self-assembly.Dedicated to Professor E.W. Fischer on the occasion of his 75th birthday. 相似文献
49.
Majid M. Heravi Dariush Ajami Bagher Mohajerani Mahmood Tajbakhsh Mitra Ghassemzadeh Kourosh Tabar-Hydar 《Monatshefte für Chemie / Chemical Monthly》2001,132(7):881-883
Summary. A new, efficient, and environmentally benign method for the cleavage of semicarbazones has been achieved by a simple reaction
of semicarbazones with clayfen under microwave irradiation.
Received January 4, 2001. Accepted (revised) March 1, 2001 相似文献
50.
Dariush Ehsani 《Mathematische Annalen》2004,330(1):93-105
We show there exists an Lp solution, for p (2,), to the -Neumann problem on an edge domain in 2 for (0,1)-forms, and we explicitly compute the singularities, which are of complex logarithmic and arctangent type, along the edge, of the solution.Mathematics Subject Classification (2000): 32W05, 35B65 相似文献