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91.
We present a concise review of the status of the standard model and of the search for new physics. 相似文献
92.
本文叙述了新铸铝光谱标样的制备过程,制备出的标样具有工艺先进,化学成分均匀,定值准确及校准曲线啮合系数高等特点。通过试用分析,结果与化学仲裁分析结果相符,很好地满足了光谱分析铸造铝合金化学成分对标样的需求。 相似文献
93.
Joel L. Lebowitz 《Journal of statistical physics》1977,16(6):463-476
We derive a new inequality for ferromagnetic Ising spin systems and then use it to obtain information about the number of phases which can coexist in such systems. We show in particular that for even interactions only two phases (up and down magnetization) can coexist below the critical temperature at zero magnetic field (h=0) whenever the energy is a continuous function of the temperature. We also prove that the derivatives with respect toh ath=0 of the odd correlation functions (triplet,...) diverge like the susceptibility in the vicinity of the critical temperature (at least for pair interactions). Our results also apply to higher order Ising spins (not just spin 1/2).Research supported in part by NSF Grant #MPS 75-20638 and USAFOR Grant #73-2430D.John Simon Guggenheim Fellow. 相似文献
94.
Sheldon M Ross 《Stochastic Processes and their Applications》1976,4(2):167-173
Consider an n-component reliability system having the property that at any time each of its components is either up (i.e., working) or down (i.e., being repaired). Each component acts independently and we suppose that each time the ith component goes up it remains up for an exponentially distributed time having mean μi, and each time it goes down it remains down for an exponentially distributed time having mean υi. We further suppose that whether or not the system itself is up at any time depends only on which components are up at that time. We are interested in the distribution of the time of first system failure when all components are initially up at time zero. In section 2 we show that this distribution has the NBU (i.e., new better than used) property, and in Section 3 we make use of this and other results to obtain a lower bound to the mean time until first system failure. 相似文献
95.
A systematic semiquantitative account of all aspects of the strong and electromagnetic interactions of all the newly discovered
hadronic states (theψ’s, theχ’s, etc.) is presented within the framework of the paracharge scheme. Extensions of ideas familiar from the SU3 classification scheme to SU4 are shown to provide an understanding of the new states seen in the decays ofψ (3.1) andψ′ (3.7), including their masses and gross decay characteristics. The decays ofψ (3.1) andψ′ (3.7) themselves are studied in some detail. Since these are of electromagnetic origin in the scheme, their electromagnetic
mixing with the resonance at 4.15 GeV (theP-state of the scheme) is important. Once this is taken into account, the resulting picture is in excellent agreement with
available data. 相似文献
96.
Sami?I.?MuslihEmail author Hosam?A.?El-Zalan Eqab?M.?Rabei 《International Journal of Theoretical Physics》2005,44(8):1271-1279
In this paper, constrained Hamiltonian systems with linear velocities are investigated by using the Hamilton–Jacobi method.
The integrablity conditions are considered on the equations of motion and the action function as well in order to obtain the
path integral quantization of singular Lagrangians with linear velocities. 相似文献
97.
Acceleration waves propagating in isotropic solids at finite temperatures are studied by applying the method of singular surfaces to a new continuum model derived statistical-mechanically from a three-dimensional lattice model. The continuum model explicitly takes into account the microscopic thermal vibrations of the constituent atoms as one of the field variables. The propagation speeds and the ratios of mechanical and thermal amplitudes for both longitudinal and transverse waves are consistently determined. The differential equations that govern the time variation of the amplitudes of the waves are also derived. The analytical results, which are valid over a wide temperature range that includes the melting point, are evaluated numerically for several materials, and their physical implications are discussed. One of the findings to be emphasized is that of the singularities of the characteristic quantities at the melting point.Received: 13 March 2003, Accepted: 20 June 2003PACS:
62.30. + d, 65.40.-bM. Sugiyama: Correspondence to
Dedicated to Prof. Ingo Müller on the occasion of his 65th birthday. 相似文献
98.
Auguste Besson 《Pramana》2004,62(3):537-540
The RunII of the Dø experiment was started in March 2001. The first preliminary results on searches for new physics are presented, with a luminosity of ~ 10 pb?1 from the data collected in 2001-2002. We report results in mSUGRA (jets + missingEt channel), GMSB (diphotons), RPV (trileptons and like sign dileptons) and large extra dimensions (dielectrons and diphotons). 相似文献
99.
I. I. Kapustina L. P. Ponomarenko O. P. Moiseenko V. A. Stonik 《Chemistry of Natural Compounds》2001,37(6):515-519
NMR spectroscopy, capillary GLC, and GLC-MS are used to study the composition of free and sulfated sterols from the far-east starfishLeptasterias alaskensis asiatica(Fischer) andL. Fisheri(Djakonov). The total free sterols of both species are shown to have similar qualitative and quantitative compositions and contain mainly7
-sterols. Sterol sulfate fractions contain cholesterol sulfate as the main component but differ in the ratios of5
:0
:7
-sterol derivatives. Possible reasons for these differences are discussed. A new steroid, 3-hydroxycholest-5-en-7-one sulfate, was isolated. 相似文献
100.
Chemical Composition of Certain Sedum Species of Kazakhstan 总被引:2,自引:0,他引:2
D. Yu. Korul''kin 《Chemistry of Natural Compounds》2001,37(3):219-223
The chemical composition of sevenSedumspecies growing in Kazakhstan was studied by chromatography. The contents of seven groups of natural compounds were determined. Comparison with markers and literature data identified 24 compounds including 9 that have not been described previously inSedumspecies 相似文献