共查询到20条相似文献,搜索用时 25 毫秒
1.
C.-W. Chen C.-H. Lin H.-P. Chiang Y.-C. Liu P.T. Leung W.S. Tse 《Applied Physics A: Materials Science & Processing》2007,89(2):377-380
The temperature dependence of the sensitivity of an optical sensor based on long-range surface plasmon resonance (LRSPR) is
studied via theoretical modeling. Both the ‘angular interrogation’ and the ‘wavelength interrogation’ modes of operation are
studied. In addition, the variation of the full width at half maximum of the LRSPR ‘reflectance dip’ is also studied as a
function of temperature, which ultimately determines the temperature dependence of the sensitivity of the sensor when the
reflectance is monitored at a fixed incident angle (‘reflectance interrogation’). It is found that while most of the time
only the ‘reflectance interrogation’ mode leads to improved sensitivity for the LRSPR sensor compared to a conventional SPR
sensor, the temperature stability of the operation of the LRSPR sensor is generally higher than (or at least comparable to)
that of the SPR sensor.
PACS 73.20.Mf; 07.07.Df 相似文献
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3.
In this paper we discuss the creation of our universe using the idea of extra dimensions. The initial, multidimensional Lagrangian contains only metric tensor. We have found many sets of the numerical values of the Lagrangian parameters corresponding to the observed low-energy physics of our Universe. Different initial parameters can lead to the same values of fundamental constants by the appropriate choice of a dimensional reduction cascade. This result diminishes the significance of the search for the ‘unique’ initial Lagrangian. We also have obtained a large number of low-energy vacua, which is known as ‘landscape’ in the string theory. 相似文献
4.
Ren Jingru Lu Suiling Xie Wei He Mao Zhang Naijian Wang Shizhi Bai Guangzhi 《中国物理C(英文版)》1997,21(2):116-120
The events of multicore shower with zenith angle tgθ>4 are found in the emulsion chamber at Mt.Kanbala.Possible mechanisms leading to these,which may predict a new phenomenon in cosmic ray experiments,are discussed. 相似文献
5.
V. I. Yakovlev 《Bulletin of the Lebedev Physics Institute》2013,40(1):17-20
Double extensive air showers were studied at the Tien Shan high-mountain scientific station of the Lebedev Physical Institute using two different installations. One measured the electron-photon shower component, the other measured Cherenkov radiation. Double showers separated by a time interval of ~100 ns were detected by both setups. The frequency of the occurrence of such showers in each setup is analyzed. It is shown that these frequencies are identical when observing vertical showers (the zenith angle ? < 60°). 相似文献
6.
Eric A Lord 《Pramana》1975,4(4):164-170
A new generalisation of Einstein’s theory is proposed which is invariant under conformal mappings. Two scalar fields are introduced
in addition to the metric tensor field, so that two special choices of gauge are available for physical interpretation, the
‘Einstein gauge’ and the ‘atomic gauge’. The theory is not unique but contains two adjustable parameters ζ anda. Witha=1 the theory viewed from the atomic gauge is Brans-Dicke theory (ω=−3/2+ζ/4). Any other choice ofa leads to a creation-field theory. In particular the theory given by the choicea=−3 possesses a cosmological solution satisfying Dirac’s ‘large numbers’ hypothesis. 相似文献
7.
A. A. Al-Rubaiee O. A. Gress K. S. Lokhtin Yu. V. Parfenov S. I. Sinegovskii 《Russian Physics Journal》2005,48(10):1004-1011
Spatial distribution of Čerenkov radiation of extensive air shower particles with energies 1013–1016 eV is simulated by the CORSIKA code for conditions and configuration of the Tunka-25 facility. Based on the calculated results,
sets of approximating functions are constructed for different primary particles and zenith angles. A comparison of the calculated
spatial distribution functions of Čerenkov light with the functions measured on the Tunka-25 facility demonstrates the feasibility
of identification of the particle initiating the shower and determination of its energy in the vicinity of the bend point
of the cosmic ray spectrum.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 7–13, October, 2005. 相似文献
8.
Rotational excitations of molecular adsorbed layers are studied theoretically. Nonlinear dynamical equations are obtained
with accounting of quadrupolar interactions between molecules and freezing of translational degrees of freedom. The equilibrium
positions of the molecules are found to be experimentally observed structures with alternating rotational ordering of planar
rotors along the direction to the nearest neighbor (for linear or square structures) under low temperature. Dynamical analysis
gives an integral of motion (energy) of the chain that in the long-wave limit leads consequently to the existence of four
phases. The first one corresponds to oscillations near equilibrium ordered states. The second phase corresponds to low-energy
rotational excitations along ‘valleys’ (easy directions in the effective potential) that do not destroy strong correlations
between molecules while structural data can show rotational disorder (melting). The third phase corresponds to an energy that
is enough to travel between ‘valleys’; only some ‘islands’ in the angle space are forbidden. Complete destruction of correlation
when the energy is over the peaks of the effective potential corresponds to the fourth phase. Therefore rotational melting
is a complex phenomenon that has several stages.
Presented at the 2nd International Conference “Physics of Liquid Matter: Modern Problems” (September 2003, Kyiv, Ukraine). 相似文献
9.
We formulate a theory of generalized Fock spaces which underlies the different forms of quantum statistics such as ‘infinite’,
Bose-Einstein and Fermi-Dirac statistics. Single-indexed systems as well as multi-indexed systems that cannot be mapped into
single-indexed systems are studied. Our theory is based on a three-tiered structure consisting of Fock space, statistics and
algebra. This general formalism not only unifies the various forms of statistics and algebras, but also allows us to construct
many new forms of quantum statistics as well as many algebras of creation and destruction operators. Some of these are: new
algebras for infinite statistics,q-statistics and its many avatars, a consistent algebra for fractional statistics, null statistics or statistics of frozen
order, ‘doubly-infinite’ statistics, many representations of orthostatistics, Hubbard statistics and its variations. 相似文献
10.
Manish Shinde Amol Pawar Soumen Karmakar Tanay Seth Varsha Raut Sunit Rane Sudha Bhoraskar Dinesh Amalnerkar 《Journal of nanoparticle research》2009,11(8):2043-2047
Uncapped silver nanoparticles were synthesized by DC arc thermal plasma technique. The synthesized nanoparticles were structurally
cubic and showed wide particle size variation (between 20–150 nm). Thick film paste formulated from such uncapped silver nanoparticles
was screen-printed on alumina substrates and the resultant ‘green’ films were fired at different firing temperatures. The
films fired at 600 °C revealed better microstructure properties and also yielded the lowest value of sheet resistance in comparison
to those corresponding to conventional peak firing temperature of 850 °C. Our findings directly support the role of silver
nanoparticles in substantially depressing the operative peak firing temperature involved in traditional conductor thick films
technology. 相似文献
11.
Results from Super-Kamiokande-I’s entire 1496 live days of solar neutrino data are presented, including the absolute flux,
energy spectrum, zenith angle (day/night) and seasonal variation. The possibility of MSW and vacuum oscillations is discussed
in light of these results. Results from the first 1289 days of Super-K-I’s atmospheric neutrino analysis are also presented,
including the evidence for νμ →ν
τ oscillations, against νμ → νsterile oscillations, and the current limits on proton decay. Finally, results based on 56 × 1019 protons on target are given for the K2K long-baseline neutrino oscillation experiment. 相似文献
12.
In this easy introduction to higher gauge theory, we describe parallel transport for particles and strings in terms of 2-connections
on 2-bundles. Just as ordinary gauge theory involves a gauge group, this generalization involves a gauge ‘2-group’. We focus
on 6 examples. First, every abelian Lie group gives a Lie 2-group; the case of U(1) yields the theory of U(1) gerbes, which
play an important role in string theory and multisymplectic geometry. Second, every group representation gives a Lie 2-group;
the representation of the Lorentz group on 4d Minkowski spacetime gives the Poincaré 2-group, which leads to a spin foam model
for Minkowski spacetime. Third, taking the adjoint representation of any Lie group on its own Lie algebra gives a ‘tangent
2-group’, which serves as a gauge 2-group in 4d BF theory, which has topological gravity as a special case. Fourth, every Lie group has an ‘inner automorphism 2-group’, which
serves as the gauge group in 4d BF theory with cosmological constant term. Fifth, every Lie group has an ‘automorphism 2-group’, which plays an important role
in the theory of nonabelian gerbes. And sixth, every compact simple Lie group gives a ‘string 2-group’. We also touch upon
higher structures such as the ‘gravity 3-group’, and the Lie 3-superalgebra that governs 11-dimensional supergravity. 相似文献
13.
Driven entirely by human curiosity, the effect of the gravitational bending of light has evolved on unforeseen paths, in an
interplay between shifts in prevailing paradigms and advance of technology, into the most unusual way to study planet populations.
The confirmation of the bending angle predicted by Einstein with the Solar Eclipse measurements from 1919 marked the breakthrough
of the theory of General Relativity, but it was not before the detection of the double image of the quasar 0957+561 that ‘gravitational
lensing’ really entered the observational era. The observation of a characteristic transient brightening of a star caused
by the gravitational deflection of its light by an intervening foreground star, constituting a ‘microlensing event’, required
even further advance in technology before it could first emerge in 1993. While it required more patience in waiting before
‘Einstein’s blip’ for the first time revealed the presence of a planet orbiting a star other than the Sun, such detections
can now be monitored live, and gravitational microlensing is not only sensitive to masses as low as that of the Moon, but
can even reveal planets around stars in galaxies other than the Milky Way. 相似文献
14.
We discuss questions pertaining to the definition of ‘momentum’, ‘momentum space’, ‘phase space’ and ‘Wigner distributions’;
for finite dimensional quantum systems. For such systems, where traditional concepts of ‘momenta’ established for continuum
situations offer little help, we propose a physically reasonable and mathematically tangible definition and use it for the
purpose of setting up Wigner distributions in a purely algebraic manner. It is found that the point of view adopted here is
limited to odd dimensional systems only. The mathematical reasons which force this situation are examined in detail 相似文献
15.
A. G. Bogdanov R. P. Kokoulin A. A. Petrukhin V. V. Shutenko I. I. Yashin 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(4):528-530
The dependence of the intensity of muon bundles recorded using the DECOR coordinate track detector on the angle between the directions of bundle arrival and the Earth’s magnetic field has been analyzed for several ranges of zenith angles. It is found that the intensity of muon bundles decreases with an increase in the transverse magnetic field component, in contrast to the results of the calculation performed on the assumption of flux azimuthal symmetry. The effect of coplanarity of particle tracks in the plane formed by the core of an extensive air shower and the Lorentz force vector is also observed. 相似文献
16.
Summary The data for 3.8 million compounds from structural databases of 32 providers were gathered and stored in a single chemical database. Duplicates are removed using the IUPAC International Chemical Identifier. After this, 2.6 million compounds remain. Each database and the final one were studied in term of uniqueness, diversity, frameworks, ‘drug-like’ and ‘lead–like’ properties. This study also shows that there are more than 87 000 frameworks in the database. It contains 2.1 million ‘drug-like’ molecules among which, more than one million are ‘lead-like’. This study has been carried out using ‘ScreeningAssistant’, a software dedicated to chemical databases management and screening sets generation. Compounds are stored in a MySQL database and all the operations on this database are carried out by Java code. The druglikeness and leadlikeness are estimated with ‘in–house’ scores using functions to estimate convenience to properties; unicity using the InChI code and diversity using molecular frameworks and fingerprints. The software has been conceived in order to facilitate the update of the database. ‘ScreeningAssistant’ is freely available under the GPL license. 相似文献
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Flux variations of cosmic ray air showers detected by LHAASO-KM2A during a thunderstorm on June 10, 2021 下载免费PDF全文
《中国物理C(英文版)》2023,47(1):015001-015001-11
The Large High Altitude Air Shower Observatory (LHAASO) has three sub-arrays, KM2A, WCDA, and WFCTA. The flux variations of cosmic ray air showers were studied by analyzing the KM2A data during a thunderstorm on June 10, 2021. The number of shower events that meet the trigger conditions increases significantly in atmospheric electric fields, with a maximum fractional increase of 20%. The variations in trigger rates (increases or decreases) were found to be strongly dependent on the primary zenith angle. The flux of secondary particles increased significantly, following a trend similar to that of shower events. To better understand the observed behavior, Monte Carlo simulations were performed with CORSIKA and G4KM2A (a code based on GEANT4). We found that the experimental data (in saturated negative fields) were in good agreement with the simulations, assuming the presence of a uniform electric field of -700 V/cm with a thickness of 1500 m in the atmosphere above the observation level. Due to the acceleration/deceleration by the atmospheric electric field, the number of secondary particles with energy above the detector threshold was modified, resulting in the changes in shower detection rate. 相似文献
19.
Laser-induced periodic surface structures (LIPSS) were generated on oriented and amorphous thick, as well as on spin-coated
thin, poly-carbonate films by polarized ArF excimer laser light. The influence of the film structure and thickness on the
LIPSS formation was demonstrated. Below a critical thickness of the spin-coated films the line-shaped structures transformed
into droplets. This droplet formation was explained by the laser-induced melting across the whole film thickness and subsequent
de-wetting on the substrate. The thickness of the layer melted by laser illumination was computed by a heat-conduction model.
Very good agreement with the critical thickness for spin-coated films was found. The original polymer film structure influences
the index of refraction of the thin upper layer modified by the laser treatment, as was proven by the dependence of the structure’s
period on the angle of incidence both for ‘s’- and ‘p’-polarized beams. The effect of the original surface roughness – grains in thick films or holes in thin films –
was studied using atomic force microscopy. It was shown that the oblique incidence of ‘s’-polarized beams results in an intensity confinement in the direction of the forward scattering and in asymmetrical interference
pattern formation around these irregularities. A new, two-dimensional grating-like structure was generated on spin-coated
films. These gratings might be used as a special kind of mask.
Received: 10 July 2001 / Accepted: 23 July 2001 / Published online: 30 August 2001 相似文献
20.
Taking the atmospheric refraction, extinction and turbulence into account, the propagation characteristic of supercontinuum laser sources in a slant path through the turbulent atmosphere is investigated. The effect of spectral width, initial spot size and zenith angle in a slant path on the beam width and propagation efficiency are studied in details. Numerical examples reveal that the beam width and propagation efficiency are different values while the spectral width varies. With the zenith angle in a slant atmospheric path increasing, the beam width of supercontinuum laser sources will increase and propagation efficiency will decrease. The initial spot size has an optimal value when spectral width and zenith angle are fixed. 相似文献