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M Abud  R Gatto  C.A Savoy 《Annals of Physics》1979,122(2):219-260
Predictions for large pT hadronic jets in high-energy proton-antiproton collisions, produced by strong interactions alone or through intermediate boson production and decay, and strong interactions, are calculated and compared. Two alternative models are considered for the strong interactions between partons: the phenomenological model of quark-scattering and lowest order QCD. In the last case, gluons are also taken into account as partons, with different choices of the gluon distribution inside the proton. The differential cross-sections for two-jet productions are given in the more interesting regions of the phase-space, as well as the predictions for the mean charge of the jets. Possible signatures for the detection of the W are stressed. In particular, W's could show up only for jets with pT near its maximum value. Our conclusions are mostly independent of the weak interaction model: the Weinberg-Salam one is considered for definiteness but alternative models are also discussed. The mean charge of the hadronic jets arising from either the weak or the strong interactions could be a rather distinctive tool in the search for the W. However, if gluons are present, their interactions could preponderate in the jet production mechanism and obstruct the search for intermediate bosons in the hadronic channels.  相似文献   
3.
Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS) has been used to determine the mass of a double-stranded 500 base-pair (bp) polymerase chain reaction (PCR) product with an average theoretical mass of the blunt-ended (i.e. unadenylated) species of 308 859.35 Da. The PCR product was generated from the linearized bacteriophage Lambda genome which is a double-stranded template. Utilization of ethanol precipitation in tandem with a rapid microdialysis step to purify and desalt the PCR product was crucial to obtain a precise mass measurement. The PCR product (0.8 pmol/μL) was electrosprayed from a solution containing 75% acetonitrile, 25 mM piperidine, and 25 mM imidazole and was infused at a rate of 200 nL/min. The average molecular mass and the corresponding precision were determined using the charge-states ranging from 172 to 235 net negative charges. The experimental mass and corresponding precision (reported as the 95% confidence interval of the mean) was 309 406 +/- 27 Da (87 ppm). The mass accuracy was compromised due to the fact that the PCR generates multiple products when using Taq polymerase due to the non-template directed 3'-adenylation. This results in a mixture of three PCR products with nearly identical mass (i.e. blunt-ended, mono-adenylated and di-adenylated) with unknown relative abundances that were not resolved in the spectrum. Thus, the experimental mass will be a weighted average of the three species which, under our experimental conditions, reflects a nearly equal concentration of the mono- and di-adenylated species. This report demonstrates that precise mass measurements of PCR products up to 309 kDa (500 bp) can be routinely obtained by ESI-FTICR requiring low femtomole amounts. Copyright 1999 John Wiley & Sons, Ltd.  相似文献   
4.
This paper describes the investigation of the potential of a quadrupole orthogonal acceleration time-of-flight mass spectrometer (Q-TOF) equipped with an atmospheric pressure ionisation interface for quantitative measurements of small molecules separated by reversed phase liquid chromatography. To this end, the detection limits and linear dynamic range in particular were studied in an LC/MS/MS experiment using 3,4-methylenedioxymethamphetamine standards and 3,4-methylenedioxyethylamphetamine for internal standardisation. In a second phase, the experiment was repeated with real biological extracts (whole blood, serum, and vitreous humour). A calibration for 3,4-methylenedioxymethamphetamine and its metabolite 3,4-methylenedioxyamphetamine was prepared in each of these matrices again using 3,4-methylenedioxyethylamphetamine as internal standard. The resulting quantitative data were compared with those obtained by liquid chromatography with fluorescence detection for the same extracts. The Q-TOF results revealed excellent sensitivity and a linear dynamic range of nearly four decades (2-10 000 pg on-column, r(2) = 0.9998, 1/x weighting). Furthermore, all the calibration curves prepared in biological material were superimposable, LC/MS/MS and LC-fluorescence, and the quantitative results for actual samples compared very favourably. It was concluded that the Q-TOF achieves a linear dynamic range for quantitative LC/MS/MS work exceeding that of fluorescence detection and at much better absolute sensitivity. Copyright 1999 John Wiley & Sons, Ltd.  相似文献   
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A unified gauge model is built with Higgs in 210⊙126⊙10 representations and intermediate symmetry $$SU(3)_c \otimes SU(2)_L \otimes SU(2)_R \otimes U(1)_{B - L} .$$ . The vacuum of the210 is in a two-dimensional stratum. From the values sin2θ W (M W ) and \(\frac{\alpha }{{\alpha _s }}(M_W )\) one determines the high scales, with the result to predict leptoquarks heavier than 1015 GeV and Majorana masses for the right-handed neutrinos around 1011 GeV.  相似文献   
7.
This is the report of Heavy Ion Physics and Quark-Gluon Plasma at WHEPP-09 which was part of Working Group-4. Discussion and work on some aspects of quark-gluon plasma believed to have created in heavy-ion collisions and in early Universe are reported.  相似文献   
8.
AP Balachandran 《Pramana》2002,59(2):359-368
We review certain emergent notions on the nature of space-time from noncommutative geometry and their radical implications. These ideas of space-time are suggested from developments in fuzzy physics, string theory, and deformation quantization. The review focuses on the ideas coming from fuzzy physics. We find models of quantum space-time like fuzzy S 4 on which states cannot be localized, but which fluctuate into other manifolds like CP3. New uncertainty principles concerning such lack of localizability on quantum space-times are formulated. Such investigations show the possibility of formulating and answering questions like the probability of finding a point of a quantum manifold in a state localized on another one. Additional striking possibilities indicated by these developments is the (generic) failure of CPT theorem and the conventional spin-statistics connection. They even suggest that Planck’s ‘constant’ may not be a constant, but an operator which does not commute with all observables. All these novel possibilities arise within the rules of conventional quantum physics, and with no serious input from gravity physics.  相似文献   
9.
The triply bridged title dinuclear copper(II) compound, [Cu2(C2H3O2)(OH)(C12H8N2)2(H2O)](NO3)2·H2O, (I), consists of a [Cu22‐CH3COO)(μ2‐OH)(phen)22‐OH2)]2+ cation (phen is 1,10‐phenanthroline), two uncoordinated nitrate anions and one water molecule. The title cation contains a distorted square‐pyramidal arrangement around each metal centre with a CuN2O3 chromophore. In the dinuclear unit, both CuII ions are linked through a hydroxide bridge and a triatomic bridging carboxylate group, and at the axial positions through a water molecule. The phenanthroline groups in neighbouring dinuclear units interdigitate along the [010] direction, generating several π–π contacts which give rise to planar arrays parallel to (001). These are in turn connected by hydrogen bonds involving the aqua and hydroxide groups as donors with the nitrate anions as acceptors. Comparisons are made with isostructural compounds having similar cationic units but different counter‐ions; the role of hydrogen bonding in the overall three‐dimensional structure and its ultimate effect on the cell dimensions are discussed.  相似文献   
10.
We revisit the non-dissipative time-dependent annular billiard and we consider the chaotic dynamics in two planes of conjugate variables in order to describe the behavior of the growth, or saturation, of the mean velocity of an ensemble of particles. We observed that the changes in the 4-d phase space occur without changing any parameter. They occur depending on where the initial conditions start. The emerging KAM islands interfere in the behavior of the particle dynamics especially in the Fermi acceleration mechanism. We show that Fermi acceleration can be suppressed, without dissipation, even considering the non-dissipative energy context.  相似文献   
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