共查询到20条相似文献，搜索用时 46 毫秒
1.
For G a classical group, an equivalence is exhibited between: | A) |
G monopoles over 3, with maximal symmetry breaking at infinity,
| | B) |
families of (rank (G)) algebraic curves inT1, along with divisors on those curves, satisfying certain constraints,
| | C) |
solutions of Nahm's equations over (rank(G)) intervals, satisfying the appropriate boundary conditions.
|
A) and B) are linked by twistor techniques, B) and C) via the Krichever method for solving non-linear differential equations, and A) and C) via the ADHMN construction, providing a unified picture of techniques for solution. Amongst other things, an asymptotic formula for the Higgs field of the monopole is computed.Communicated by A. Jaffe 相似文献
2.
This paper presents a theoretical method for design quasi-optics power combiner of solid-state millimeter — wave sources, and gives theory analysis to some problem concerned. Here is the structure: | 1. |
Epitome of microwave power combiner.
| | 2. |
Gauss light beam and the field distribution in the resonator.
| | 3. |
The design of the resonator
| | (1) |
Confocal resonator
| | (2) |
Objective function
| | (3) |
The global optimization method and the program flow chart.
| | 4. |
Example
| | 5. |
Reference
|
相似文献
3.
New possibilities in the solution to the general relativity problems appearing in the conformally invariant generalization of Einsteins equations are addressed. The conformally invariant equations and their solutions possess the following properties:
| 1. |
The Cauchy problem is posed without any constraints on the Cauchy data.
| | 2. |
Solutions with discontinuities on space-like hypersurfaces are admitted.
| | 3. |
A conserved current vector appears.
| | 4. |
A new function of state similar to entropy appears.
| | 5. |
The gauge vector and the lambda term can be interpreted in terms of degrees of freedom of 1/2-spin particles.
|
The paper briefly describes these properties and discusses possible methods to use them for the solution of general relativity problems. 相似文献
4.
Optical properties of the Sm 3+ ion in YAG crystals have been investigated, in particular:
| – |
- the energy level diagram of Sm:YAG has been established.
|
| – |
- the emission characteristics of the metastable state4G5/2 have been determined.
|
| – |
- the oscillator strengths of various Sm transitions have been investigated using the Judd-Ofelt theory.
|
The relatively large emission cross section and long fluorescence lifetime enable red laser action to be obtained. 相似文献
5.
In this talk the discussion of nuclear physics studied by hyperfine methods is limited to a few topics of high actuality: | (a) |
Isomer shift data for 2+ rotational states gave r/r values much smaller than predicted by the simple centrifugal stretching model. They provide evidence for a strong Coriolis anti-pairing effect as recent detailed microscopic calculations show.
| | (b) |
The Coriolis force causes also the famous back-bending effect at high rotational angular momenta. This phenomenon is not yet really understood. MeasuredgR values in this region would be very informative. The present situation of this challenging task is discussed.
| | (c) |
Precisely measured magnetic dipole moments of high-spin few-particle states allow in favourable cases the derivation of the meson exchange contribution. The general situation and new results are reported.
| | (d) |
Quite a few electric quadrupole moments of high spin states of several tin isotopes have recently been measured. The discussion in terms of the simple shell model reveals already interesting features. Especially the subshell filling effect is nicely exhibited.
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相似文献
7.
We consider two-dimensional Bernoulli percolation at density p>p
c
and establish the following results: | 1. |
The probability,P
N
(p), that the origin is in afinite cluster of sizeN obeys|
相似文献
8.
| 1. |
The method for solving the reconstruction problem proposed here makes it possible to use physically grounded a priori information which is reliable for many radio-astronomy problems.
| | 2. |
The method reduces the incorrectly formulated problem of reconstructing the nonnegative curve to a correctly formulated problem of reconstructing a monotonic curve. The numerical-differentiation operation remains incorrect; this operation is comparatively simple to carry out.
| | 3. |
It is possible to incorporate in the numerical differentiation and the solution of the mathematical-programming problems additional a priori information, whose nature is determined in each particular case.
| | 4. |
The solution of the reconstruction problem reduces to the application of numerical-analysis methods which have been worked out thoroughly, and there are no fundamental difficulties involved here.
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相似文献
9.
| 1. |
The intensities of hypersensitive transitions at 293 K increase with decreasing Ln−O bond length in both praseodymium and
europium complexes. The intensity increase can also be caused, for praseodymium crystals, by lower energy of f-d transition
bands.
|
| 2. |
The temperature dependence of the3H4→3Po transition for Pr(CF3COO)3·3H2O crystal probably indicates a phase transformation occurring at about 50 K.
|
| 3. |
The electronic lines are accompanied be weak vibronic components for transitions that obey the selection rules †J=0,2.
|
| 4. |
The intensities of vibronic sidebands in excitation spectra are stronger than those in emission ones for europium single crystals
at 77 K.
|
| 5. |
Lowering of the energy of f-d bands is observed in the crystals in the order Pr(CCl3COO)3<Pr(CF3COO)3, what can affect the vibronic coupling more strongly in the former case.
|
| 6. |
The relative-intensity relation for the two types of europium crystal (I and II) indicate stronger distortion of coordination
polyhedra in trifluoroacetate crystals.
|
| 7. |
The number of components of the5Do→7FJ transition indicates the existence of two symmetry centers of the Eu3+ ion in trichloroacetate, thus confirming results obtained by the X-ray method.
|
Institute of Chemistry, University of Wroclaw, F. Joliot-Curie 14, 50-383 Wrockaw, Poland, Published in Zhurnal Prikladnoi
Spektroskopii, Vol. 62, No. 5, pp. 105–114, September–October, 1995. 相似文献
10.
We consider a model of a random copolymer at a selective interface which undergoes a localization/delocalization transition. In spite of the several rigorous results available for this model,
the theoretical characterization of the phase transition has remained elusive and there is still no agreement about several
important issues, for example the behavior of the polymer near the phase transition line. From a rigorous viewpoint non coinciding
upper and lower bounds on the critical line are known.
In this paper we combine numerical computations with rigorous arguments to get to a better understanding of the phase diagram.
Our main results include:
| – |
Various numerical observations that suggest that the critical line lies strictly in between the two bounds.
|
| – |
A rigorous statistical test based on concentration inequalities and super–additivity, for determining whether a given point
of the phase diagram is in the localized phase. This is applied in particular to show that, with a very low level of error,
the lower bound does not coincide with the critical line.
|
| – |
An analysis of the precise asymptotic behavior of the partition function in the delocalized phase, with particular attention
to the effect of rare atypical stretches in the disorder sequence and on whether or not in the delocalized regime the polymer path has a Brownian scaling.
|
| – |
A new proof of the lower bound on the critical line. This proof relies on a characterization of the localized regime which
is more appealing for interpreting the numerical data.
|
2000 MSC: 60K37, 82B44, 82B80 相似文献
11.
This special issue of Applied Physics B – Lasers and Optics attempts to document the current status and trends of environmental trace gas detection through a collection of 32 invited papers motivated in part by the need for and importance of a detailed understanding of our environment. Although numerous traditional optical methods, gas chromatography, and mass spectrometry have served us extremely well in atmospheric and environmental trace gas detection, promising new sensing and precise measurement techniques based on laser spectroscopy have emerged and been successfully used in numerous applications. The concept and timing of this special issue has been stimulated to some extent by recent exciting developments of several novel technologies, such as diode and fiber lasers for the optical communications industry, diode-pumped solid-state lasers, and novel bulk and waveguide infrared nonlinear materials. These can be applied to the ultra-sensitive, highly selective detection and real-time analysis of a large number of trace gas species by means of absorption spectroscopy in the mid-infrared fingerprint region, which contains virtually all the fundamental vibrational modes of molecules. Reduction of cost and complexity makes such spectroscopic sources more universally available and user friendly to both established and new fields that include air quality, atmospheric chemistry, industrial, traffic, and rural emissions, chemical analysis and process control, and medical applications.This issue, consisting of two parts, chronicles some of the most significant and representative current research trends. It is hoped that this issue will inspire new directions to both specialists and newcomers in which to drive this exciting field and envision future applications of environmental sensing.Part I: Spectroscopic air monitoring techniques and instrumentation
| • |
Tunable laser spectroscopy with near-IR diode lasers, lead salt diode lasers, and parametric frequency conversion sources
|
Part II: Applications of laser- and non-laser-based spectroscopic techniques
| • |
Differential absorption lidar (DIAL) and spectroscopy (DOAS) for atmospheric research
| | • |
Laser photoacoustic spectroscopy
| | • |
Fourier transform infrared spectroscopy
|
I would like to express my gratitude to excellent authors and constructive reviewers from around the world for making this issue a reality over a mere six-month period. My special thanks also go to Prof. F. Träger, Editor-in-Chief of Applied Physics B – Lasers and Optics, for providing me with the opportunity for this special issue, and to Victoria Schutter (Rice University), Gabriele Kuppstadt-Brand (University of Kassel), and Marlene Hillen (Springer-Verlag) for doing a superb job in assembling this issue. 相似文献
12.
In the present paper calculations have been made of the association and interaction elastic energies for monovalent cation impurities and divalent cation impurities unassociated and associated with cation vacancies in the form of dipoles with dislocationsa/2 r + + < rCa + + r_{ + + }< r_{Ca^{ + + } }
in the compressed region of dislocation, mainly on the dislocationa/2110 {100}. In the case of divalent impurities associated with cation vacancies in the form of dipoles the increase in impurity concentration can take place at all impurities as in the above mentioned case and additionally Sr++
| | b) |
the increase in monovalent impurity concentration (r
+>164-01) around dislocations takes place, excepting lithium, in the extended region of the dislocation of both types. Our calculations are compared with the published experimental data.
|
相似文献
13.
After over 20 years of development, noise mapping software is, today, a professional tool that is widely used by many people with different backgrounds and experience in the applications, the data and the software used. The user has the possibility to influence the quality of the result of the noise mapping process. The major factors affecting good practice include: • | the user’s knowledge of the standard, | • | the user’s knowledge of the software, | • | documentation of software functions and its implementation of the standard, | • | quality assurance of software implementation, | • | documentation of software settings in calculation results, | • | the user’s analysis of the quality and impact of the input data. |
Several methods are available to ensure good practice and improve the quality of output through such methods as standardization and documentation, training and user certification. For example, in 2006, the European Commission Working Group Assessment of Exposure to Noise produced the “Good Practice Guide for Strategic Noise Mapping and the Production of Associated Data on Noise Exposure” Version 2.This article will describe the major factors where user influences the quality of the results and the methods to ensure good practice and improving the quality of output. 相似文献
14.
In this paper we intend to present some path-integral studies in the problem of confinement in the presence of fermionic and
scalar magnetic monopole fields through:
| 1. |
A Wilson Loop Path-Integral Evaluation associated to an effective second-quantized electromagnetic field generated by chiral
abelian point-like monopole magnetic field current.
|
| 2. |
A Path-Integral Bosonization analysis of Quarks fields interacting with Kalb-Ramond fields considered as an effective Disorder
Field Theory of a Q.C.D. vacuum of heavier monopoles.
|
| 3. |
Improvements on the Wilson Loops evaluations in the well-known ADHM Antonov-Ebert model for Cooper pairs of point-like fermionic
magnetic monopoles.
|
相似文献
15.
This paper continues the analysis of the quantum states introduced in previous works and determined by the universal asymptotic
structure of four-dimensional asymptotically flat vacuum spacetimes at null infinity M. It is now focused on the quantum state λ
M
, of a massless conformally coupled scalar field propagating in M. λ
M
is “holographically” induced in the bulk by the universal BMS-invariant state λ defined on the future null infinity of M. It is done by means of the correspondence between observables in the bulk and those on the boundary at future null infinity
discussed in previous papers. This induction is possible when some requirements are fulfilled, in particular whenever the
spacetime M and the associated unphysical one, M͂, are globally hyperbolic and M admits future time infinity i
+. λ
M
coincides with Minkowski vacuum if M is Minkowski spacetime. It is now proved that, in the general case of a curved spacetime M, the state λ
M
enjoys the following further remarkable properties:
| (i) |
λ
M
is invariant under the (unit component of the Lie) group of isometries of the bulk spacetime M.
|
| (ii) |
λ
M
fulfills a natural energy-positivity condition with respect to every notion of Killing time (if any) in the bulk spacetime
M: If M admits a time-like Killing vector, the associated one-parameter group of isometries is represented by a strongly-continuous
unitary group in the GNS representation of λ
M
. The unitary group has positive self-adjoint generator without zero modes in the one-particle space. In this case λ
M
is a so-called regular ground state.
|
| (iii) |
λ
M
is (globally) Hadamard in M and thus it can be used as the starting point for the perturbative renormalisation procedure of QFT of in M.
|
相似文献
16.
Recently, folk questions on the smoothability of Cauchy hypersurfaces and time functions of a globally hyperbolic spacetime M, have been solved. Here we give further results, applicable to several problems: | (1) | Any compact spacelike acausal submanifold H with boundary can be extended to a spacelike Cauchy hypersurface S. If H were only achronal, counterexamples to the smooth extension exist, but a continuous extension (in fact, valid for any compact achronal subset K) is still possible. | | (2) | Given any spacelike Cauchy hypersurface S, a Cauchy temporal function
(i.e., a smooth function with past-directed timelike gradient everywhere, and Cauchy hypersurfaces as levels) with
is constructed – thus, the spacetime splits orthogonally as
in a canonical way. |
Even more, accurate versions of this last result are obtained if the Cauchy hypersurface S were non-spacelike (including non-smooth, or achronal but non-acausal). 相似文献
17.
Our results lead to the following conclusions.
| 1. |
A CVL with a nonlinear frequency converter can be regarded as a source of high-power UV radiation discretel tunable in three
wavelengths.
|
| 2. |
The presence of the CVL beam of a low-coherence (single-pass) radiation is one of the main factors that limi the efficiency
of the nonlinear conversion.
|
The authors are grateful to O. Ipat’eva, A. Kokh, and A. Yurkin of the “Single-Crystal” Collective Technica Institute for
supplying the high-quality high-voltage equipment elements. 相似文献
18.
A heat engine is a machine which uses the temperature difference between a hot and a cold reservoir to extract work. Here
both reservoirs are quantum systems and a heat engine is described by a unitary transformation which decreases the average energy of the bipartite system. On the molecular scale, the ability of implementing a (good) unitary heat engine
is closely connected to the ability of performing logical operations and classical computing. This is shown by several examples:
| (1) |
The most elementary heat engine is a SWAP-gate acting on 1 hot and 1 cold two-level systems with different energy gaps. |
| (2) |
An optimal unitary heat engine on a pair of 3-level systems can directly implement OR and NOT gates, as well as copy operations.
The ability to implement this heat engine on each pair of 3-level systems taken from the hot and the cold ensemble therefore
allows universal classical computation.
|
| (3) |
Optimal heat engines operating on one hot and one cold oscillator mode with different frequencies are able to calculate polynomials
and roots approximately.
|
| (4) |
An optimal heat engine acting on 1 hot and n cold 2-level systems with different level spacings can even solve the NP-complete problem KNAPSACK. Whereas it is already
known that the determination of ground states of interacting many-particle systems is NP-hard, the optimal heat engine is
a thermodynamic problem which is NP-hard even for n non-interacting spin systems. This result suggests that there may be complexity-theoretic limitations on the efficiency of molecular heat
engines.
|
相似文献
19.
We have developed a sequential radiochemical separation method (SRCS) in order to isolate each trans-uranium element (TRU)
contained in a TRU target (or fuel) irradiated in the experimental fast reactor JOYO.
The chemical separation procedures for SRCS consist of the following steps:
| 1 |
Target dissolution with an 8 M (mol/dm3) of HNO3 solution including hydrogen peroxides as a valence control reagent for Pu and Np to their tetravalent states.
|
| 2 |
Sequential elution of fission products (FP’s) including trivalent actinides (An(III)) and lanthanides (Ln(III)), U(VI), Pu(III),
and Np(IV) from an anion exchange resin column. The decontamination factor (DF) of Pu(III) in the Np(IV) was much higher than
106.
|
| 3 |
Group separation for Ln(III) and An(III). The DF of Ln(III) for the separated An(III) exceeds 5×103 and that of Am and Cm for the separated An(III)-fraction exceeds 104.
|
| 4 |
Mutual separation of Am(III) and Cm(III), also for each lanthanide.
|
The SRCS flow sheet was applied to the analyses of MOX fuels irradiated in the experimental fast reactor JOYO. On the basis
of isotope analysis, the transmutation and incineration behaviour of trans-uranium nuclides were elucidated. The transmutation
ratios of irradiated two TRU targets were evaluated and ranged from 8.05 to 10.79 % in this study. 相似文献
20.
We present the results of numerical simulation and physical experiments to verify the possibility of generating a virtual
superluminal VLF source by HF ionospheric heating with a scanning beam.
The detection of VLF emission was carried out for the source created in two ways:
| – |
- by scanning the HF beam in opposite directions with different velocities and
|
| – |
- by amplitude modulation of a stationary HF beam.
|
The amplitude-frequency characteristics of signals obtained in the experiments show the possibility of radiation pattern control
of the VLF emission excited by a scanning HF beam.
Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika,
Vol. 41, No. 3, pp. 298–312, March, 1998. 相似文献
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