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151.
S. Bollanti F. Bonfigli E. Burattini P. Di Lazzaro F. Flora A. Grilli T. Letardi N. Lisi A. Marinai L. Mezi D. Murra C. Zheng 《Applied physics. B, Lasers and optics》2003,76(3):277-284
A long-pulse-width high-output energy (120 ns FWHM, 7 J) XeCl laser has been focused on thin tape targets (Cu and Ta) to generate
more than 100-ns-long (FWHM) EUV pulses in the 10–30 nm spectral region, suitable for projection microlithography. The conversion
efficiency was more than 20% over a 2π solid angle. We observed debris emission using a gated CCD camera, and measured the
debris speed for different irradiation conditions. We found irradiation conditions such that the measured velocities were
low enough that simple mechanical devices combined with krypton at low-pressure could efficiently stop both ionic debris and
cluster debris. Our results show that a suitable combination of driving-laser characteristics, target material and thickness,
environment gas and mechanical choppers can make clean and increase the power of EUV solid-target laser-plasma sources.
Received: 21 October 2002 / Published online: 26 February 2003
RID="*"
ID="*"Corresponding author. Fax: +39-06/9400-5334, E-mail: bollanti@frascati.enea.it 相似文献
152.
We develop a notion of an n-fold monoidal category and show that it corresponds in a precise way to the notion of an n-fold loop space. Specifically, the group completion of the nerve of such a category is an n-fold loop space, and free n-fold monoidal categories give rise to a finite simplicial operad of the same homotopy type as the classical little cubes operad used to parametrize the higher H-space structure of an n-fold loop space. We also show directly that this operad has the same homotopy type as the n-th Smith filtration of the Barratt-Eccles operad and the n-th filtration of Berger's complete graph operad. Moreover, this operad contains an equivalent preoperad which gives rise to Milgram's small model for der="0" style="vertical-align:bottom" width="56" alt="View the MathML source" title="View the MathML source" src="http://ars.els-cdn.com/content/image/1-s2.0-S0001870803000653-si1.gif"> when n=2 and is very closely related to Milgram's model of der="0" style="vertical-align:bottom" width="62" alt="View the MathML source" title="View the MathML source" src="http://ars.els-cdn.com/content/image/1-s2.0-S0001870803000653-si2.gif"> for n>2. 相似文献
153.
杨朝武 《科技情报开发与经济》2002,12(5):184-185
简述了“坝上等弦等角放线法”在古石水电站枢组大坝施工放线中的应用,总结了坝上放线法的应用效果,分析了在“三心拱坝”等其它坝型中的推广应用,对今后拱坝施工放线提供一种新的方法。 相似文献
154.
图G的圆色数xc(G)(也称为星色数)是图的色数的一种推广,给出了图的圆色数等于其色数的一些充分条件。 相似文献
155.
We present an extensive experimental study and scaling analysis of friction of gelatin gels on glass. At low driving velocities,
sliding occurs via propagation of periodic self-healing slip pulses whose velocity is limited by collective diffusion of the
gel network. Healing can be attributed to a frictional instability occurring at the slip velocity V = V
c. For V > V
c, sliding is homogeneous and friction is ruled by the shear-thinning rheology of an interfacial layer of thickness of order
the (nanometric) mesh size, containing a solution of polymer chain ends hanging from the network. In spite of its high degree
of confinement, the rheology of this system does not differ qualitatively from known bulk ones. The observed ageing of the
static friction threshold reveals the slow increase of adhesive bonding between chain ends and glass. Such structural ageing
is compatible with the existence of a velocity-weakening regime at velocities smaller than V
c, hence with the existence of the healing instability.
Received: 7 March 2003 / Accepted: 2 May 2003 / Published online: 11 June 2003
RID="b"
ID="b"e-mail: ronsin@gps.jussieu.fr 相似文献
156.
O. N. Bakharev N. Zelders H. B. Brom A. Schnepf H. Schnöckel L. Jos de Jongh 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,24(1-3):101-104
We present
69,71Ga-NMR experiments on
microcrystalline samples of the recently discovered
supramolecular compound Ga
84
[
N
(
SiMe
3
)
2
]
20
Li
6
Br
2
(
thf
)
20
.
2
toluene, which is composed of
ligand-coordinated Ga84 metal clusters,
packed together in a fully ordered crystalline matrix. The
compound is highly conducting and even shows superconductivity
below T
c
~ 7.2 K. Our preliminary
results between 10-300 K show a metallic-like behavior: the
nuclear spin-lattice relaxation rate T
1
-1
follows the Korringa law
69
(
T
1
T
)
-1
= 0.36 s
-1
K
-1
, but with a relaxation rate approximately three
times smaller than in bulk -Ga
metal. No quantum-size effects are observed, the Korringa law
being followed down to 10 K, whereas the quantum-gaps for
individual clusters should amount to ~
10
3
K. These results therefore suggest a transport process based on
intermolecular charge transfer, similar as in alkali-doped
fullerenes and silicon-clathrates. 相似文献
157.
Guoen Hu 《Journal of Mathematical Analysis and Applications》2003,283(2):351-361
der="0" style="vertical-align:bottom" width="49" alt="View the MathML source" title="View the MathML source" src="http://ars.els-cdn.com/content/image/1-s2.0-S0022247X02004985-si1.gif"> boundedness is considered for the commutator of higher-dimensional Marcinkiewicz integral. Some conditions implying the der="0" style="vertical-align:bottom" width="49" alt="View the MathML source" title="View the MathML source" src="http://ars.els-cdn.com/content/image/1-s2.0-S0022247X02004985-si2.gif"> and the der="0" style="vertical-align:bottom" width="49" alt="View the MathML source" title="View the MathML source" src="http://ars.els-cdn.com/content/image/1-s2.0-S0022247X02004985-si3.gif"> boundedness for the commutator of the Marcinkiewicz integral are obtained. 相似文献
158.
GU Zhaoyan LIU Qiang XU Bing HAN Jiamao YANG Shiling DING Zhongli & LIU Tungsheng Institute of Geology Geophysics Chinese Academy of Sciences Beijing China Correspondence should be addressed to Gu Zhaoyan 《科学通报(英文版)》2003,48(12):1271-1276
Two modes of photosynthesis predominate in terres-REPORTS trial plants: the C3 and C4 modes[1]. The C3 mode is used by all of trees, bushes, and cold season grasses. The C4 mode is used by the most of tropical and warm season grasses. They are disadvantaged relative to C3 plants at high CO2/O2 ratios because of the additional energy ex-pense needed to concentrate CO2 in the bundle-sheath cells. At low CO2/O2, however, C4 plants can achieve a relatively high quantum yield by suppressin… 相似文献
159.
GEChendong O.Slaymaker T.F.Pedersen 《科学通报(英文版)》2003,48(21):2357-2361
Pb geochronology and sediment core profiles of organic carbon, total sulfur and organic carbon isotope (d 13C) values were used to reconstruct the local environ-mental history of the Shamei Lagoon, located in the Wan-quan River Estuary, eastern Hainan Island, China. Totalsulfur and d 13C values decreased upwards in the top 30 cm of a sediment core that spanned the last 200 years of deposi-tion. Total sulfur concentration and d 13C values respectively decreased upward from 1.92% to 0.36%, and -20.63?to -23.64? The C/S ratio in the 19th century and earlier was relatively stable in the range of 0.47—0.80, and there was a positive correlation between organic carbon and total sulfur. Since around 1900 AD, the C/S ratio increased rapidly to a maximum of 3.94, but no simple correlation was found be-tween organic carbon and total sulfur during this more re-cent period. These results indicated that before 1800 AD, the lagoon had a fully marine character, and the location of to-day抯 Wanquan River Estuary was an open embayment.From 1800 to 1900, the salinity of Shamei Lagoon decreased noticeably. The amount of seawater which could enter thelagoon decreased gradually as the Yudai spit grew. Today,seawater scarcely affects the lagoon; it is essentially a fresh-water basin. 相似文献
160.
R. R. Mhaskar S. E. Olson G. Raithel 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(2):221-227
A method of imaging distributions of cold atoms under the presence of large
trapping-field-induced level shifts is investigated. By utilizing a probe
laser tuned to an open transition, the fluorescence yield per atom is
largely fixed throughout the trap volume, independent of the trapping
field. This enables a reliable conversion of fluorescence images into
atomic-density profiles. The method is applied to measure distributions of
87Rb atoms in a high-gradient (2.7 kG/cm) magnetic atom guide. We
characterize the parameters for which the open-channel imaging method
performs best. Results of quantum Monte Carlo simulations verify the
underlying assumptions of the method. 相似文献