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991.
An easy-to-prepare chemosensor, 2-(4-formylphenyl)phenanthroimidazole 1, synthesized by facile one-step condensation under microwave irradiation, has been indicated to be a colorimetric and fluorometric
probe for fluoride anion with good sensitivity and high selectivity. This probe shows obvious red shift and absorbance intensity
changes in UV absorption and fluorescence spectra in the presence of fluoride anions. Such color and absorbance intensity
changes are attributed to the deprotonation of N-H on the imidazole moiety with fluoride anion. 相似文献
992.
We present a laser architecture to obtain continuous-wave blue radiation at 488 nm. A 808 nm diode-pumped the Nd:YVO4 crystal emitting at 914 nm. A part of the pump power was then absorbed by the Nd:YVO4 crystal. The remaining was used to pump the Nd:YLiF4 (Nd:YLF) crystal emitting at 1047 nm. Intracavity sum-frequency mixing at 914 and 1047 nm was then realized in a BiB3O6 (BiBO) crystal to reach the blue radiation. We obtained a continuous-wave output power of 339 mW at 488 nm with a pump laser diode emitting 18.3 W at 808 nm. 相似文献
993.
The factors affecting performance of fractured wells are analyzed in this work. The static and dynamic geologic data of fractured
well and fracturing treatment parameters obtained from 51 fractured wells in sand reservoirs of Zhongyuan oilfield are analyzed
by applying the grey correlation method. Ten parameters are screened, including penetrability, porosity, net thickness, oil
saturation, water cut, average daily production, and injection rate, amount cementing front spacer, amount sand-carrying agent
and amount sand. With the novel Radial Basis Function neural network model based on immune principles, 13 parameters of 42
wells out of 51 are used as the input samples and the stimulation ratios as the output samples. The nonlinear interrelationship
between the input samples and output samples are investigated, and a productivity prediction model of optimizing fracture
design is established. The data of the rest 7 wells are used to test the model. The results show that the relative errors
are all less than 7%, which proves that the novel Radial Basis Function neural network model based on immune principles has
less calculation, high precision and good generalization ability. 相似文献
994.
This paper is devoted to studying the relationship between meromorphic functions f(z) and g(z) when their differential polynomials satisfy sharing condition weaker than sharing one value IM. 相似文献
995.
Yun Wang Juan Ni Hao Chi Xianmin Zhang Shilie Zheng Xiaofeng Jin 《Optics Communications》2011,284(16-17):3928-3932
A novel photonic technique for instantaneous frequency measurement of microwave signal based on phase modulation to intensity modulation conversion is proposed and demonstrated. In the proposed system, an optical carrier is modulated by a microwave signal with its frequency to be measured through a phase modulator. The phase-modulated optical signal is then converted to intensity-modulated signals in two independent paths using a dispersive media and a frequency discriminator respectively. Since the dependence of the received microwave power on the input microwave frequency in the two paths differs, the microwave power ratio between the two paths can be used to uniquely determine the microwave frequency. The major advantages of the approach lie in that only one laser source and the bias-free phase modulator is employed in the system, which improves the stability of the system. Experimental demonstrations of the frequency measurement based on the proposed approach are presented. 相似文献
996.
We theoretically investigate cavity-linewidth narrowing by means of voltage-controlled induced transparency in asymmetric double quantum dot system. The impact of voltage on frequency pulling and cavity linewidth narrowing is discussed. The linewidth and position of the cavity transmission can be engineered by the bias voltage. The scheme may be useful in designing novel optoelectronic devices. 相似文献
997.
Miniussi E Pozzo M Baraldi A Vesselli E Zhan RR Comelli G Menteş TO Niño MA Locatelli A Lizzit S Alfè D 《Physical review letters》2011,106(21):216101
We report on a novel approach to determine the relationship between the corrugation and the thermal stability of epitaxial graphene grown on a strongly interacting substrate. According to our density functional theory calculations, the C single layer grown on Re(0001) is strongly corrugated, with a buckling of 1.6 ?, yielding a simulated C 1s core level spectrum which is in excellent agreement with the experimental one. We found that corrugation is closely knit with the thermal stability of the C network: C-C bond breaking is favored in the strongly buckled regions of the moiré cell, though it requires the presence of diffusing graphene layer vacancies. 相似文献
998.
Aprile E Arisaka K Arneodo F Askin A Baudis L Behrens A Bokeloh K Brown E Bruch T Bruno G Cardoso JM Chen WT Choi B Cline D Duchovni E Fattori S Ferella AD Gao F Giboni KL Gross E Kish A Lam CW Lamblin J Lang RF Levy C Lim KE Lin Q Lindemann S Lindner M Lopes JA Lung K Undagoitia TM Mei Y Fernandez AJ Ni K Oberlack U Orrigo SE Pantic E Persiani R Plante G Ribeiro AC Santorelli R dos Santos JM Sartorelli G Schumann M Selvi M Shagin P Simgen H Teymourian A Thers D Vitells O Wang H Weber M 《Physical review letters》2011,107(13):131302
We present results from the direct search for dark matter with the XENON100 detector, installed underground at the Laboratori Nazionali del Gran Sasso of INFN, Italy. XENON100 is a two-phase time-projection chamber with a 62 kg liquid xenon target. Interaction vertex reconstruction in three dimensions with millimeter precision allows the selection of only the innermost 48 kg as the ultralow background fiducial target. In 100.9 live days of data, acquired between January and June 2010, no evidence for dark matter is found. Three candidate events were observed in the signal region with an expected background of (1.8 ± 0.6) events. This leads to the most stringent limit on dark matter interactions today, excluding spin-independent elastic weakly interacting massive particle (WIMP) nucleon scattering cross sections above 7.0 × 10(-45) cm(2) for a WIMP mass of 50 GeV/c(2) at 90% confidence level. 相似文献
999.
1000.