共查询到20条相似文献,搜索用时 15 毫秒
1.
Stefan Marinov 《General Relativity and Gravitation》1980,12(1):57-66
The report is given on a local measurement of the absolute velocity of a laboratory. This is the resultant velocity due to all types of motion in which the laboratory takes part (about the Earth's axis, about the Sun, about the galactic center, about the center of the cluster of galaxies). 相似文献
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Results are reported from two experiments in which the benefit of supplementing speechreading with auditorily presented information about the speech signal was investigated. In experiment I, speechreading was supplemented with information about the prosody of the speech signal. For ten normal-hearing subjects with no experience in speechreading, the intelligibility score for sentences increased significantly when speechreading was supplemented with information about the overall amplitude of the speech signal, information about the fundamental frequency, or both. Binary information about voicing appeared not to be a significant supplement. In experiment II, the best-scoring supplements of experiment I were compared with two supplementary signals from our previous studies, i.e., information about the sound-pressure levels in two 1-oct filter bands centered at 500 and 3160 Hz, or information about the frequencies of the first and second formants from voiced speech segments. Sentence-intelligibility scores were measured for 24 normal-hearing subjects with no experience in speechreading, and for 12 normal-hearing experienced speechreaders. For the inexperienced speechreaders, the sound-pressure levels appeared to be the best supplement (87.1% correct syllables). For the experienced speechreaders, the formant-frequency information (88.6% correct), and the fundamental-frequency plus amplitude information (86.0% correct), were equally efficient supplements as the sound-pressure information (86.1% correct). Discrimination of phonemes (both consonants and vowels) was measured for the group of 24 inexperienced speechreaders. Percentage correct responses, confusion among phonemes, and the percentage of transmitted information about different types of manner and place of articulation and about the feature voicing are presented. 相似文献
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《Physics letters. A》2006,357(2):136-140
CdS nanoarrays with the particles' diameter of about 1 nm were assembled in the nanochannels of the host of VSB-5 nanorods. Obvious UV–vis absorption peaks with the onsets of about 350–400 nm were clearly observed. Compared with the band-gap absorption at about 515 nm of the large CdS particles at room temperature, about 115–165 nm of the blue-shifts occurred for the nanoarrays due to the quantum confinement effect. 相似文献
4.
文中叙述了HL-1M托卡马克硼化真空紫外光谱区杂质辐射的观测结果。分析得出:硼化有效地控制等离子体中的杂质,其中,氧杂质减少约65%,碳杂质减少约60%,金属杂质减少约85%。 相似文献
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Photoluminescence of a silver-doped glass 总被引:1,自引:0,他引:1
S. E. Paje J. Llopis M. A. Villegas J. M. Fernández Navarro 《Applied Physics A: Materials Science & Processing》1996,63(5):431-434
The absorption, emission and excitation spectra of Ag+ ions in a soda lime glass doped with two different concentration of silver are investigated. Absorption spectra exhibit a main broad band peaked at about 260 nm (4.77 eV) with a shoulder at about 227 nm (5.46 eV). The relative height of the shoulder depends on silver concentration in the glass. Emission spectra of Ag+ are dominated by an ultraviolet broad band at about 330 nm (3.76 eV). The excitation spectra for this emission show a preponderant broad band peaked at about 227 nm (5.46 eV) which coincides with peak position of the shoulder displayed in the optical absorption spectra. A weak broad featureless emission band centred at about 550 nm (2.25 eV) with an excitation peak at about 242 nm (5.12 eV) is tentatively related to an impurity from the host silica glass rather than originated in silver-type centres. Comparison of the luminescence decay curves for both emissions show substantial differences between them. Consequently, the emissions in the time-resolved spectra can easily be discriminated. 相似文献
7.
We report findings from a national telephone survey on levels of knowledge about and attitudes toward nanotechnology that
demonstrate how people make decisions about emerging technologies. Our findings confirm previous research that suggests that
people form opinions and attitudes even in the absence of relevant scientific or policy-related information. In fact, our
data show that cognitive shortcuts or heuristics – often provided by mass media – are currently a key factor in influencing
how the public thinks about nanotechnology and about its risks and benefits, and in determining the level of support among
the public for further funding for research in this area. 相似文献
8.
The disintegration yield of the organic dye DODCI dissolved in ethylene glycol and methanol due to cw excitation to the S1-state and due to intense picosecond pulse excitation to higher excited singlet states is determined. In the S1-state DODCI molecules disintegrate after about 5×104 excitation cycles while rhodamine 6G molecules in ethanol survive about 13×106 excitation cycles. In higher excited singlet states the DODCI molecules disintegrate on average after about 10 to 30 excitation cycles, while rhodamine 6G gets destroyed after about 140 excitation cycles. 相似文献
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质量均匀分布的物体相对质心轴的转动惯量,通常是由它的几何量表示,这称为转动惯量的几何表示.如果给定物体的顶点坐标,它相对任意轴的转动惯量可以由这些顶点坐标表示,这称为转动惯量的代数表示.由转动惯量的平行轴定理,得到杆和三角形板相对任意转轴转动惯量的代数表示.作为简单应用,得到三角形边框相对质心轴转动惯量的几何量表示. 相似文献
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实验发现硫脲能在电极表面形成一吸附层并阻碍氢在电极表面的析出还原反应,此吸附层在电位约-0.6V时发生结构转变,进一步实验显示硫脲吸附层的结构在-0.9V时为疏松的,在-0.3V~-0.5V时为致密的,而在-0.8V~-0.6V时为两种结构的中间过渡态。 相似文献
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结合负载限制型磁绝缘线振荡器(MILO)和渐变型MILO的特点提出并设计了P波段混合型MILO的结构,主要以负载限制型MILO结构作为雏形,将其内部仅含有的1根提取叶片用3根长度渐变的慢波叶片组成的渐变段替换。该结构可更好地实现束波相互作用,并使提取间隙电场与MILO输出同轴结构处的电场达到更好的匹配,增加微波输出功率。器件纵向总长度为47 cm,外筒直径为44 cm。优化后的2.5维全电磁粒子模拟结果表明:在二极管工作电压550 keV、电流约57 kA的情况下,输出微波的中心频率为640 MHz,平均功率为4.27 GW,束波转换效率为13.6%,器件4 ns时起振,6 ns达到饱和,且微波输出功率十分稳定,最终输出微波模式为TEM模。 相似文献
14.
M. S. Bhagwat A. Höll A. Krassnigg C. D. Roberts S. V. Wright 《Few-Body Systems》2007,40(3-4):209-235
We examine the applicability and viability of methods to obtain knowledge about bound states from information provided solely
in Euclidean space. Rudimentary methods can be adequate if one only requires information about the ground and first excited
state and assumptions made about analytic properties are valid. However, to obtain information from Schwinger functions about
higher mass states, something more sophisticated is necessary. A method based on the correlator matrix can be dependable when
operators are carefully tuned and errors are small. This method is nevertheless not competitive when an unambiguous analytic
continuation of even a single Schwinger function to complex momenta is available. 相似文献
15.
The measurement of the density of liquid argon at a pressure of about 1000 GPa in a cylindrical setup transforming shock compression to quasi-isentropic compression gives a value of about 9 g/cm3. The experimental data are compared with calculations. The results bring out clearly that no anomaly is observed in the behavior of isentropically compressed liquid argon at pressures up to about 1000 GPa. 相似文献
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Zaixuan Zhang Bizhi Dai Laixiao Li Haifeng Xu Honglin Liu Jianfeng Wang Chenxia Li Insoo S. Kim 《中国光学快报(英文版)》2005,3(11)
The amplification effects on forward and backward stimulated Brillouin scattering (SBS) lines in the forward pumped S-band distributed G652 fiber Raman amplifier (FRA) have been studied. There is a pump threshold power of Stokes backward stimulated Brillouin scattering (B-SBS) line in the forward pumped G652 FRA, it is about 1 mW. The Stokes B-SBS lines are amplified by FRA and fiber Brillouin Brillouin gain. In experimental work, the saturation gain of the first order Stokes backward SBS line is about 58 dB and the saturation gain of 25-km G652 forward FRA is about 25 dB, so the gain of FBA is about 33 dB. The forward stimulated Brillouin scattering (F-SBS) is generated and amplified in S-band G652 FRA. The stimulated threshold powers of the forward first order Stokes SBS (SB1-), second order Stokes SBS (SB2-), and third order SBS (SB3-) in the forward pumped FRA are 2.3, 1.6, and 1.6 mW,respectively. In experimental work, the saturation gains of SB1-, SB2-, and SB3- are about 38, 62, and 60 dB, respectively. The saturation Raman gain of 25-km G652 forward FRA is about 8.8 dB, so the Brillouin gains of SB1-, SB2-, and SB3- are about 29.2, 53.2, and 51.2 dB, respectively. The forward and backward cascaded SBS lines have been observed. 相似文献
18.
Elizabeth A. Corley Youngjae Kim Dietram A. Scheufele 《Journal of nanoparticle research》2011,13(12):7041-7055
Despite the significant increase in the use of nanotechnology in academic research and commercial products over the past decade,
there have been few studies that have explored scientists’ perceptions and attitudes about the technology. In this article,
we use survey data from the leading U.S. nano-scientists to explore their perceptions about two issues: the public communication
of research findings and media coverage of nanotechnology, which serves as one relatively rapid outlet for public communication.
We find that leading U.S. nano-scientists do see an important connection between the public communication of research findings
and public attitudes about science. Also, there is a connection between the scientists’ perceptions about media coverage and
their views on the timing of public communication; scientists with positive attitudes about the media are more likely to support
immediate public communication of research findings, while others believe that communication should take place only after
research findings have been published through a peer-review process. We also demonstrate that journalists might have a more
challenging time getting scientists to talk with them about nanotechnology news stories because nano-scientists tend to view
media coverage of nanotechnology as less credible and less accurate than general science media coverage. We conclude that
leading U.S. nano-scientists do feel a sense of responsibility for communicating their research findings to the public, but
attitudes about the timing and the pathway of that communication vary across the group. 相似文献
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To obtain further insight into the deformation of a plate in the laser forming process, the temperature gradient mechanism (TGM) is studied. Through the investigation, it can be found that, under the processing conditions of TGM, the plate not only bends about the x-axis but also about the y-axis. An analytical model estimate of the bending angle about the y-axis is constructed based on the theories of heat transfer and the mechanics of elastoplasticity. Numerical simulations are carried out to investigate the deformation of the plate about the y-axis by choosing the different process parameters. The analytically based estimate is used to suggest suitable starting values for the simulation process of calculated results. The study of the bending about the y-axis may describe more fully the deformation of a plate, which is helpful in high-precision forming. 相似文献