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排序方式: 共有160条查询结果,搜索用时 640 毫秒
1.
We consider the equation \(\rm f^{\prime\prime}+{A}(z){f}=0\) with linearly independent solutions f1,2, where A(z) is a transcendental entire function of finite order. Conditions are given on A(z) which ensure that max{λ(f1),λ(f2)} = ∞, where λ(g) denotes the exponent of convergence of the zeros of g. We show as a special case of a further result that if P(z) is a non-constant, real, even polynomial with positive leading coefficient then every non-trivial solution of \(\rm f^{\prime\prime}+{e}^P{f}=0\) satisfies λ(f) = ∞. Finally we consider the particular equation \(\rm f^{\prime\prime}+({e}^Z-K){f}=0\) where K is a constant, which is of interest in that, depending on K, either every solution has λ(f) = ∞ or there exist two independent solutions f1, f2 each with λ(fi) ≤ 1. 相似文献
2.
Ilpo O. O. Korhonen 《Journal of mass spectrometry : JMS》1988,23(10):729-735
The mass spectral fragmentation of a homologous series of methyl esters of 2-chloro n-alkanoic acids ranging from acetic (C2) to eicosanoic (C20) acid on electron impact has been investigated. The fragmentation pathways were elucidated with the aid of the first field-free region metastable ions, the results being presented with one compound, i.e. with ionized methyl 2-chloro-octauoate. Owing to the Cl/H exchanges and to the formation of the non-chlorinated parent esters prior to the fragmentations the spectra show the peak pairs with and without the chlorine atom. The effects become more evident with increasing chain length; shown most visually by the abundance ratios of the McLafferty rearrangement ions atm/z108/110 and 74, and fragments at m/z121/123 and 87. 相似文献
3.
4.
This is a corrigendum to our paper, "On a class of prime entire functions", published in Acta Math. Sin., Engl. Ser., 25, 1647-1652 (2009). 相似文献
5.
We have employed atomic-scale molecular dynamics simulations to address ion transport through transient water pores in phospholipid membranes. The formation of a water pore is induced by a transmembrane ionic charge imbalance, which gives rise to a significant potential difference across the membrane. The subsequent transport of ions through the pore discharges the transmembrane potential and makes the water pore metastable, leading eventually to its sealing. The findings highlight the importance of ionic charge fluctuations in spontaneous pore formation and their role in ion leakage through protein-free lipid membranes. 相似文献
6.
7.
Gerard A. van Albada Ilpo Mutikainen Urho Turpeinen Jan Reedijk 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):m179-m181
The title mononuclear complex, [Cu(CO3)(C8H7N5)(H2O)]·2H2O, was obtained by fixation of CO2 by a mixture of copper(II) tetrafluoroborate and the ligand bis(pyrimidin‐2‐yl)amine in ethanol/water. The CuII ion of the complex has a distorted square‐pyramidal environment, with a basal plane formed by two N atoms of the ligand and two chelating O atoms of the carbonate group, while the apical position is occupied by the O atom of the coordinating water molecule. In the solid state, hydrogen‐bonding interactions are dominant, the most unusual being the Watson–Crick‐type coplanar ligand pairing through two N—H?N bonds. Lattice water molecules also participate in hydrogen bonding. 相似文献
8.
Ilkka Ojanperä Samuel Mesihää Ilpo Rasanen Anna Pelander Raimo A. Ketola 《Analytical and bioanalytical chemistry》2016,408(13):3395-3400
9.
The S-wave annihilation contribution to the pp? inelastic cross section at low energies is calculated in a quark-antiquark rearrangement model which includes the effect of NΔ̄ + N?Δ and ΔΔ̄ intermediate states. This mechanism, which leads automatically to a separable interaction, is able to account for about 15% of the observed cross section. The extension of the model to P-waves is also outlined. 相似文献
10.
Opper AK Korkmaz E Hutcheon DA Abegg R Davis CA Finlay RW Green PW Greeniaus LG Jordan DV Niskanen JA O'Rielly GV Porcelli TA Reitzner SD Walden PL Yen S 《Physical review letters》2003,91(21):212302
The forward-backward asymmetry in np-->dpi(0), which must be zero in the center-of-mass system if charge symmetry is respected, has been measured to be [17.2+/-8.0(stat)+/-5.5(syst)]x10(-4), at an incident neutron energy of 279.5 MeV. This observable is compared to recent chiral effective field theory calculations, with implications regarding the du quark mass difference. 相似文献