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141.
Investigation on improving characteristics of two-cell SBS system with CCl4/C2H5OH liquid mixture 下载免费PDF全文
In order to improve the performance of the two-cell stimulated Brillouin scattering (SBS) system, this paper proposes the methods of using mixtures, which require amplifier media to have small absorption rate, and generator media to have high optical breakdown threshold and Brillouin frequency shift equal to that of the amplification media. The characteristics of the two-cell SBS system are studied experimentally by using CCl4 as amplifier medium and CCl4, C2H5OH and CCl4/C2H5OH liquid mixture as generator medium pumped by Nd:YAG Q-switched laser. The obtained results show that liquid mixture in generator cell improves the power load ability, phase conjugation fidelity, energy reflectivity (ER) and ER stability. 相似文献
142.
P. Yi A. Aldahan G. Possnert X. L. Hou P. He B. Wang 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(3):1797-1801
Iodine speciation plays a significant role in iodine volatilizing into atmosphere from the seas, as well as serving as a biological indicator. Despite this importance, the data on iodine species revealed inconclusive evidence of what factors controlling speciation transformation. We here present new data on profiles of 129I speciation in the Baltic Proper during November 2009. Along with the two earlier investigations (August 2006 and April 2007), an assessment of seasonal variation of 129I species is presented. The results show that, due to the anoxic nature of Baltic Proper, presence of 129IO3 ? in the Baltic Proper does not follow an obvious seasonal cycle, as the case with 129I?. Concentrations of 129I? in the Baltic Proper exhibit higher values in summer than the other two seasons (spring and winter), which might be associated with degrading of organic matter and release from sediment to water column that is more pronounced during summer. 129I? in surface water from the three seasons does not reflect the release function from the reprocessing facilities during the period April 2007 to November 2009. Consequently variability of 129I? in surface seawater of the Baltic Proper depends, to some extent, on local physical as well as biochemical conditions. 相似文献
143.
Shao Su Xinpan Wei Yuanyuan Guo Yiling Zhong Yuanyuan Su Qing Huang Chunhai Fan Yao He 《Particle & Particle Systems Characterization》2013,30(4):326-331
A new kind of silicon nanowire (SiNWs)‐based nanoelectrode assembly, a gold‐nanoparticle‐decorated silicon nanowire array (AuNPs@SiNWsAr), is employed for the construction of high‐performance electrochemical sensors. Significantly, the electrochemical nanosensors are capable of sensitive detection of various electroactive molecules (e.g., dopamine (DA), ascorbic acid (AA), hydrogen peroxide (H2O2), and glucose). Further, DA molecules loaded on the surface of AuNPs@SiNWsAr preserve stable high electroactivity overnight without special protection, while free DA molecules may lose their biological activity due to severe oxidization in ambient environment. These findings may offer new opportunities for the design of high‐performance electrochemical nanosensors with high sensitivity and robust stability. 相似文献
144.
The detailed reaction pathway and coke formation mechanism over Pt/metal oxide nanoparticles during the steam reforming of ethanol(SRE) at 300℃were studied.The catalysts were prepared by incipient wetness impregnation method and were characterized with CO pulse chemisorption, BET surface measurement,oxygen adsorption,ethanol-TPD,NH3-TPD,and TPO.The SRE activity of the catalysts with steam/ethanol molar ratio of 3/1 was tested using a continuous fixed-bed reactor.Strong interaction between Pt and supports causes lower H2 production temperatures and no C2H4 formation,while weak interaction leads to C2H4 formation and strong bonded CO on Pt particles during ethanol-TPD. H2 production over Pt-based catalysts is mainly resulted from the decomposition and dehydrogenation of ethanol,and decarbonylation of acetaldehyde.Meanwhile,coke can be formed from acetaldehyde,acetone,C2H4 and CO.However,when the interaction between Pt and supports is weak,more coke is formed especially from acetone,C2H4 and CO.When the interaction is strong,no coke formation is observed due to high oxygen storage capacity of the catalyst. 相似文献
145.
Study of multi-nucleon transfer reactions in 58, 64Ni + 207Pb collisions at the velocity filter SHIP
Comas V. F. Heinz S. Hofmann S. Ackermann D. Heredia J. A. Heßberger F. P. Khuyagbaatar J. Kindler B. Lommel B. Mann R. 《The European Physical Journal A - Hadrons and Nuclei》2013,49(9):1-17
The European Physical Journal A - We investigated multi-nucleon transfer reactions in collisions of 58Ni + 207Pb and 64Ni + 207Pb at Coulomb barrier energies. The new aspect is that we used a... 相似文献
146.
Muhammad Ejaz Bhanukiran Sunkara Lakhinder Kamboj Jibao He Vijay T. John Noshir S. Pesika Scott M. Grayson 《Journal of polymer science. Part A, Polymer chemistry》2013,51(15):3314-3322
An efficient and novel one‐pot process is developed to immobilize the atom transfer radical polymerization (ATRP) initiators onto the surface of fully pyrolyzed carbon hard spheres (CHSs) via a radical trapping process from the in situ thermal decomposition of bis(bromomethylbenzoyl)peroxide. The CHSs do not require any additional preparative treatment prior to the initiator immobilization. Styrene and methyl methacrylate are polymerized onto initiator‐immobilized CHSs by surface‐initiated atomic transfer radical polymerization (SI‐ATRP). Samples are characterized using Fourier transform infrared, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscopy. These methods of characterization confirmed that all the CHSs are coated with a uniform layer of grafted polymer. This efficient, one‐pot immobilization of ATRP‐initiators represents an exceptionally simple route for the rapid preparation of various polymer‐coated carbon‐based nanomaterials using SI‐ATRP. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3314–3322 相似文献
147.
Simulation of near-infrared photodiode detectors based on β-FeSi_2/4H-SiC heterojunctions 总被引:1,自引:0,他引:1 下载免费PDF全文
In this paper,we propose a near-infrared p-type β-FeSi2/n-type 4H-SiC heterojunction photodetector with semiconducting silicide(β-FeSi2) as the active region for the first time.The optoelectronic characteristics of the photodetector are simulated using a commercial simulator at room temperature.The results show that the photodetector has a good rectifying character and a good response to near-infrared light.Interface states should be minimized to obtain a lower reverse leakage current.The response spectrum of the β-FeSi2/4H-SiC detector,which consists of a p-type β-FeSi2 absorption layer with a doping concentration of 1×1015cm-3 and a thickness of 2.5 μm,has a peak of 755 mA/W at 1.42 μm.The illumination of the SiC side obtains a higher responsivity than that of the β-FeSi2 side.The results illustrate that the β-FeSi2/4H-SiC heterojunction can be used as a near-infrared photodetector compatible with near-infrared optically-activated SiC-based power switching devices. 相似文献
148.
We present a method by which to determine the bulk viscosity of water from pulse duration measurements of stimulated Brillouin scattering (SBS). Beginning from a common model of Brillouin scattering, the bulk viscosity is shown to play an important role in Brillouin linewidth determination. Pulse durations of SBS back-reflected optical pulses are measured over the temperature range of 5-40℃. SBS linewidths are de- termined via Fourier transformation of the time-domain results, and the bulk viscosity of water is measured and derived from the obtained values. Our results show that the proposed method for measurement of pulse durations is an effective approach for determining bulk viscosity. The method can be easily extended to determine bulk viscosities of other Newtonian liquids. 相似文献
149.
Impacts of air pressure on the evolution of nanosecond pulse discharge products 总被引:1,自引:0,他引:1 下载免费PDF全文
Based on the nonequilibrium plasma dynamics of air discharge, a dynamic model of zero-dimensional plasma is established by combining the component density equation, the Boltzmann equation, and the energy transfer equation. The evolution properties of nanosecond pulse discharge (NPD) plasma under different air pressures are calculated. The results show that the air pressure has significant impacts on the NPD products and the peak values of particle number density for particles such as O atoms, O3 molecules, N2(A3) molecules in excited states, and NO molecules. It increases at first and then decreases with the increase of air pressure. On the other hand, the peak values of particle number density for N2(B3) and N2(C3) molecules in excited states are only slightly affected by the air pressure. 相似文献
150.
An echelle diffraction grating based high-resolution spectrometer-on-chip on silicon oxynitride (SiON) waveguide platform operated at a wavelength range of 850 nm is demonstrated. The chip comprises 120 output waveguides with 0.25-nm wavelength channel spacing and has a size of only 11 × 6 (mm). The experimental results show that the insertion loss is-14 dB, the measured adjacent channel crosstalk is less than -25 dB, the 3 dB channel bandwidth is < 0.1 nm, and the channel non-uniformity is 3 dB for 56 channels with a wavelength ranging from 838 to 852 nm. 相似文献