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1.
Isoperimetric inequalities are applied to a moving-boundaryproblem for doubly-connected domains. This problem occurs forexample in electrochemistry, in which case the domains in questionare the electrolyte of an electrolytic cell. The two electrodessurrounding the electrolyte are assumed to grow or dissolve,at different rates in general, by electrochemical reaction.We obtain optimal estimates showing, for example, that the leastchange in volume of each electrode always occurs in sphericalsymmetry.  相似文献   
2.
Salicyladehyde benzoylhydrazone (SBH) has three groups suitable for forming coordination bond with transition metal. The UV-vis absorption spectra of SBH and its Co(II) complexes in various media were studied by using the deconvolution method. It is found that the structure of complex in solution is different from those in solid crystals. The nature of complexes in solution depends on acidity of the phenolic proton of SBH and on the medium. In neutral or slightly acid medium, the SBH is a non-charged bidentate ligand. And the "free" hydroxyl group on the SBH molecule makes it possible to form hydrogen bonds in solution. In basic medium, the SBH is a mono, negatively charged tridentates ligand.  相似文献   
3.
Abstract Global warming is expected to affect the ecosystem in the Northeast Atlantic, and substantial changes will also affect the aquaculture industry. Farming of salmon and trout is the biggest aquaculture industry in Norway, with an export value of about 3 billion US dollars in 2007. The objective of the paper is to analyze the potential economic effect a general increase in sea temperature can have on the Norwegian salmon aquaculture industry. The assessment of the economic impact of global warming is made possible by estimating a growth function, which explicitly includes sea water temperature. The analysis compares the economic effect of a climate change on fish farming plants in the south and the north of Norway. The scenarios are based on a model with monthly seasonal variation in temperature.  相似文献   
4.
Gas-phase protonation thermochemistry of arginine   总被引:1,自引:0,他引:1  
The gas-phase basicity (GB), proton affinity (PA), and protonation entropy (DeltapS degrees (M)=S degrees (MH+)-S degrees (M)) of arginine (Arg) have been experimentally determined by the extended kinetic method using an electrospray ionization quadrupole time-of-flight (ESI-Q-TOF) mass spectrometer. This method provides GB(Arg)=1004.3+/-2.2 (4.9) kJ.mol(-1) (indicated errors are standard deviations, and in parentheses, 95% confidence limits are given). Consideration of previous experimental data using a fast atom bombardment ionization tandem sector mass spectrometer slightly modifies these estimates since GB(Arg)=1005.9+/-3.1 (6.6) kJ.mol(-1). Lower limits of the proton affinity, PA(Arg)=1046+/-4 (7) kJ.mol(-1), and of the "protonation entropy", DeltapS degrees (Arg)=S degrees (ArgH+)-S degrees (Arg)=-27+/-7 (15) J.mol(-1).K(-1), are also provided by the experiments. Theoretical calculations conducted at the B3LYP/6-311+G(3df,2p)//B3LYP/6-31+G(d,p) level, including 298 K enthalpy correction, predict a proton affinity value of ca. 1053 kJ.mol-1 after consideration of isodesmic proton-transfer reactions with guanidine as the reference base. Computations including explicit treatment of hindered rotations and mixing of conformers confirm that a noticeable entropy loss does occur upon protonation, which leads to a theoretical DeltapS degrees (Arg) term of ca. -45 J.mol(-1).K(-1). The following evaluated thermochemical parameter values are proposed: GB(Arg)=1005+/-3 kJ.mol(-1); PA(Arg)=1051+/-5 kJ.mol(-1), and DeltapS degrees (Arg)=-45+/-12 J.mol(-1).K(-1).  相似文献   
5.
The lower excited states of 2-benzoylthiophene have been studied using ab initio quantum chemical methods based on multiconfigurational wave functions. Six singlet and six triplet excited states have been characterized. The geometry has been optimized for the two lowest triplet states, which are responsible for the photoreactivity of the chromophore in the photosensitizing drug tiaprofenic acid. The T1(π → π?) and T2(n → π?) states have been found to be close in energy with the π → π? state slightly lower. The excited states have been characterized using density difference and spin density plots. The different photochemical behaviour of the two triplet states can be rationalized from the theoretical data.  相似文献   
6.
Results are presented from a theoretical study of the × 6Σ+, A 6Σ+ and 6Δ electronic states of CrH using multiconfiguration second-order perturbation theory in the multi-state formalism (MS-CASPT2). It is shown that the results for the spectroscopic constants and radiative lifetimes for the A state are in agreement with experiment and an earlier multireference configuration interaction study only if the two close lying × and A states are allowed to interact at a level of approximation that includes dynamic correlation.  相似文献   
7.
Abstract— Photoinactivation in vitro at pH 7.0 of catalases from different sources (bovine liver, spinach leaves, and Micrococcus lysodeikticus) was studied. The wavelength of the inactivating light was close to the Soret peak of catalase. No great difference in light sensitivity between soluble catalases were found; the inactivation cross sections found ranged from 3.8.10-4 to 5.0. 10-4Å2/molecule. The inactivation quantum yield is 2.2. 10-5 for bovine liver catalase and 3.110-5 for Micrococcus catalase. The quantum yield for soluble spinach catalase is of a similar order of magnitude. There are some indications of a greater resistance to photodestruction of the spinach leaf catalase activity associated with small particles.  相似文献   
8.
N Barik  RN Mishra 《Pramana》2001,56(4):519-536
Considering the nucleon as consisting entirely of its valence quarks confined independently in a scalar-vector harmonic potential; unpolarized structure functions F 1(x, μ 2) and F 2(x, μ 2) are derived in the Bjorken limit under certain simplifying assumptions; from which valence quark distribution functions u v(x, μ 2) and d v(x, μ 2) are appropriately extracted satisfying the normalization constraints. QCD-evolution of these input distributions from a model scale of μ 2=0.07 GeV2 to a higher Q 2 scale of Q 0 2 =15 GeV2 yields xu v(x, Q 0 2 ) and xd v(x, Q 0 2 ) in good agreement with experimental data. The gluon and sea-quark distributions such as G(x, Q 0 2 ) and q s(x, Q 0 2 ) are dynamically generated with a reasonable qualitative agreement with the available data; using the leading order renormalization group equations with appropriate valence-quark distributions as the input.  相似文献   
9.
Abstract— –Small amounts of N -methyl phenazonium methosulphate (PMS) added to a suspension of Chlorella pyrenoidosa accelerate the emission of the long-lived far-red induced afterglow without greatly changing the amount of light emitted. The effect is noticeable in dilute suspensions at a PMS concentration of 10-9 M. The concept of afterglow unit is introduced and defined as that part of the sample in which the rate of energy reemission can be controlled by a single molecule of PMS. The number of chlorophyll molecules per afterglow unit is about 105. It is possible that the afterglow unit is identical to the thylakoid.
The rate constant for the final first order decay phase of afterglow at room temperature is about 0.7 min-1 without PMS and about 3 times larger for a unit with one PMS molecule.
Diuron (DCMU) lowers the rate of afterglow decay. Desaspidin on the other hand decreases the amount of light emitted without affecting the decay rate. Carbonylcyanide- m -chlorophenyl hydrazone (CCCP) decreases the afterglow over the whole time-range and increases the decay rate. A kinetic model is developed to account for the results.  相似文献   
10.
RN Mohapatra 《Pramana》2000,55(1-2):289-296
It is shown that if the supersymmetric Standard Model (MSSM) emerges as the low energy limit of a high scale left-right symmetric gauge structure, the number of uncontrollable CP violating phases of MSSM are drastically reduced. In particular it guarantees the vanishing of the dangerous phases that were at the root of the so called SUSY CP problem. Such a symmetric gauge structure is independently motivated by the smallness of neutrino masses that arise via seesaw mechanism automatic in the theory. The minimal version of this theory also provides an explanation of the smallness of ε′/ε as a consequence of the high scale parity invariance. This talk is based on work done in collaboration with K S Babu and B Dutta.  相似文献   
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