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101.
Reductive methylation of 1-carbomethoxy-4, 6-dimethoxynaphthalene in anhydrous ammonia gave 1-methyl-1-carbomethoxy-6-methoxy-1, 4-dihydronaphthalene in good yield. Metal ammonia reduction of the ketones 12 and 18 provided an expedient pathway for the synthesis of the ,β-unsaturated ketones 17 and 19 respectively. 相似文献
102.
Patiño P. Sánchez N. Suhr H. Hernández N. 《Plasma Chemistry and Plasma Processing》1999,19(2):241-254
The oxidation of 13 liquid olefins with either high-voltage or radio frequency (RF) glow discharges has been studied. The reactions were carried out by making the oxygen plasma reach the low vapor pressure substrate. Product formation has proved to be selective—epoxides, aldehydes, ketones, and low quantities of carboxylic acids being the most important species. Fragmentation products were only observed in the traps of the RF system for the most volatile olefin of this study. This indicates that, except for this case, the most relevant interaction of this study has been the heterogeneous reaction of the plasma with the liquid. Total conversion, i.e., mass transformed against initial mass of substrate, has been studied as a function of temperature of the liquid and oxygen flow rate in the reactor, this ranging from 15 to 53.6 mmol/hr in the high-voltage system and 13 to 270 mmol/hr in the RF device. The optimum conversions were 27 to 99%. A correlation between these results and the behavior of the O(
3
P) population in the discharge allows us to conclude that this is the most relevant species to the oxidation process. A discussion relating the structures of the olefins with the composition of the mixtures produced by the oxidation is also presented. 相似文献
103.
Arun Kumar Pati 《Pramana》2002,59(2):221-228
Entangling an unknown qubit with one type of reference state is generally impossible. However, entangling an unknown qubit
with two types of reference states is possible. To achieve this, we introduce a new class of states called zero sum amplitude (ZSA) multipartite, pure entangled states for qubits and study their salient features. Using shared-ZSA states, local operations
and classical communication, we give a protocol for creating multipartite entangled states of an unknown quantum state with
two types of reference states at remote places. This provides a way of encoding an unknown pure qubit state into a multiqubit
entangled state. 相似文献
104.
105.
We propose for the first time a few examples of stable transition metal complexes of an all-metal antiaromatic molecule Al4Li4. We demonstrate that these all-metal species can be stabilized by complexation with 3d transition metals very similar to their organic counterpart, C4H4. Complexation to transition metal ions reduces the frontier orbital energies and introduces aromatic charactersitics. We consider a series of such complexes: [eta4-(Al4Li4)-Fe(CO)3, eta2,sigma2-(Al4Li4)-Ni, and (Al4Li4)2Ni] and compare and contrast their energetics with their organometallic counterparts. Fragmentation energy, orbital correlation energy analysis, and the nucleus-independent chemical shift (NICS) values support the complexation-induced stabilities in these systems. 相似文献
106.
The previously proposed left-right-symmetric SU(2)L × SU(2)R × U(1) theory permits one of the two neutral gauge particles N1 and N2 to be particularly light (<mW+L) compatible with all neutrin-data and the present atomic parity experiments. Distinguishing features of this theory (with the light mass solution) for e?e+ → μ+μ? and π+π? at PETRA and PEP energies as compared to the SU(2) × U(1) predictions are given. 相似文献
107.
108.
We present a theory of nonequilibrium long range charge transfer between donor and acceptor centers in a model polymer mediated by magnetic exciton (Kondo) bound states. Our model produces electron tunneling lengths easily exceeding 10 A, as observed recently in DNA and organic charge transfer systems. This long ranged tunneling is effective for weak to intermediate donor-bridge coupling, and is enhanced both by weak to intermediate strength Coulomb hole-electron attraction (through the orthogonality catastrophe) and by coupling to local vibrational modes. 相似文献
109.
The max algebra consists of the nonnegative real numbers equipped with two binary operations, maximization and multiplication. We consider the semimodules over max algebra and study the properties of the weak basis and weak dimension of the semi-modules. Moreover, we obtain the characterizations of those linear operators that preserve rank of matrices over max-algebra. 相似文献
110.
Most cytokines are present at reduced amounts in body fluids due to their biological features of production, release, and action mechanisms. The required time between sampling and their measurement is critical for diagnosis and treatment. Electrochemical nanobiosensors offer the possibility to be tailor-made and cost affordable, producing direct and rapid readouts with low sample volume, explaining their feasibility in timely measurements and potential in designing unique and multiplexed Point-Of-Care (POC) testing platforms. This review summarizes and discusses the measurement limitations of the standard methods and the recent progress on electrochemical nanobiosensors as a plausible alternative to measuring them. 相似文献