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51.
Magnetic-Bottle and Velocity-Map Imaging Photoelectron Spectroscopy of APS- (A=C14H10 or Anthracene): Electron Structure,Spin-Orbit Coupling of APS·, and Dipole-Bound State of APS-
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Qin-qin Yuan Zheng Yang Ren-zhong Li Wesley J. Transue Zhi-peng Li Ling Jiang Niranjan Govind Christopher C. Cummins Xue-Bin Wang 《化学物理学报(中文版)》2018,31(4):463-470
Gaseous dibenzo-7-phosphanorbornadiene P-sulfide anions APS-(A=C14H10 or anthracene) were generated via electrospray ionization, and characterized by magnetic-bottle photoelectron spectroscopy, velocity-map imaging (VMI) photoelectron spectroscopy, and quantum chemical calculations. The electron affinity (EA) and spin-orbit (SO) splitting of the APS· radical are determined from the photoelectron spectra and Franck-Condon factor simulations to be EA=(2.62±0.05) eV and SO splitting=(43±7) meV. VMI photoelectron images show strong and sharp peaks near the detachment threshold with an identical electron kinetic energy (eKE) of 17.9 meV at three different detachment wavelengths, which are therefore assigned to autodetachment from dipole-bound anion states. The B3LYP/6-31++G(d, p) calculations indicate APS· has a dipole moment of 3.31 Debye, large enough to support a dipole-bound electron. 相似文献
52.
Youxiang Wang David M. Eichhorn Niranjan Goswami Qiaoqin Zhao D. Paul Rillema 《Journal of chemical crystallography》1999,29(3):277-281
The complex [Ru(bpy)2(DMSO)C1]PF6, where bpy is 2,2-bipyridine and DMSO is dimethylsulfoxide, crystallizes in the triclinic space group P1¯ (#2) with a = 8.873 (2), b = 12.805 (4), c = 12.864 (4) Å, = 97.76(3), = 106.45(2), = 107.88(2); Z = 2, and d
calc = 1.75 mg/m3. The coordination geometry is that of a distorted octahedron with a cis –RuN4SCl arrangement of coordinating atoms. The four Ru—N distances to the bpy ligands are 2.082(5), 2.092(4), 2.044(4), and 2.078(5) Å. The Ru—Cl distance is 2.421(2) Å and the Ru—S distance to DMSO is 2.260(1) Å. The Ru—N bond distance trans to Cl is the shortest; the Ru—N bond distance trans to S is the longest. The complex is oxidized and reduced reversibly at 1.13 and –1.37 V vs. SSCE, respectively. It displays electronic absorptions at 515, 480 (1.5 × 104), 342 (1.5 × 104), 292 (1.2 × 105), and 240 nm (6.2 × 104) and has a broad emission band centered at 607 nm at 77 K in a 4:1 ethanol/methanol glass. The emission lifetime at room temperature is less than the pulse width of the laser, < 20 ns. 相似文献
53.
A mathematical model is derived to elucidate the dominant mechanism governing film formation. It leads to a relation between
film thickness and film radius spreading with time. Inclusion of evaporation and shear stress was made with extension to non-Newtonian
fluid. The advantages and disadvantages of this process with applications are reviewed.
相似文献
54.
JPC – Journal of Planar Chromatography – Modern TLC - India is the main producer of palmarosa oil obtained from rosha grass (Cymbopogan martini var. motia) of family Graminae. The... 相似文献
55.
Priyankar Paira Krishnendu B. Sahu Nirup B. Mondal Niranjan P. Sahu Peter Luger 《Tetrahedron》2008,64(18):4026-4036
Phase transfer catalyzed one-pot syntheses of fused oxazepino, oxazocino, and oxazonino quinolinium cations and quinolones were achieved from 8-hydroxy quinoline derivatives with 1,ω-dihaloalkanes. Structures of all the products were elucidated by spectroscopic analysis. Single crystal X-ray crystallographic analysis of three compounds and graphical superposition of the structures indicate that products having seven-membered ring are less planar compared to the product having eight-membered ring. 相似文献
56.
Niranjan Balachandran 《Designs, Codes and Cryptography》2012,65(3):353-364
Let ${\mathcal{F}}$ be a (0, 1) matrix. A (0, 1) matrix ${\mathcal{M}}$ is said to have ${\mathcal{F}}$ as a configuration if there is a submatrix of ${\mathcal{M}}$ which is a row and column permutation of ${\mathcal{F}}$ . We say that a matrix ${\mathcal{M}}$ is simple if it has no repeated columns. For a given ${v \in \mathbb{N}}$ , we shall denote by forb ${(v, \mathcal{F})}$ the maximum number of columns in a simple (0, 1) matrix with v rows for which ${\mathcal{F}}$ does not occur as a configuration. We say that a matrix ${\mathcal{M}}$ is maximal for ${\mathcal{F}}$ if ${\mathcal{M}}$ has forb ${(v, \mathcal{F})}$ columns. In this paper we show that for certain natural choices of ${\mathcal{F}}$ , forb ${(v, \mathcal{F})\leq\frac{\binom{v}{t}}{t+1}}$ . In particular this gives an extremal characterization for Steiner t-designs as maximal (0, 1) matrices in terms of certain forbidden configurations. 相似文献
57.
Brain tumor segmentation is a crucial step in surgical and treatment planning. Intensity-based active contour models such as gradient vector flow (GVF), magneto static active contour (MAC) and fluid vector flow (FVF) have been proposed to segment homogeneous objects/tumors in medical images. In this study, extensive experiments are done to analyze the performance of intensity-based techniques for homogeneous tumors on brain magnetic resonance (MR) images. The analysis shows that the state-of-art methods fail to segment homogeneous tumors against similar background or when these tumors show partial diversity toward the background. They also have preconvergence problem in case of false edges/saddle points. However, the presence of weak edges and diffused edges (due to edema around the tumor) leads to oversegmentation by intensity-based techniques. Therefore, the proposed method content-based active contour (CBAC) uses both intensity and texture information present within the active contour to overcome above-stated problems capturing large range in an image. It also proposes a novel use of Gray-Level Co-occurrence Matrix to define texture space for tumor segmentation. The effectiveness of this method is tested on two different real data sets (55 patients - more than 600 images) containing five different types of homogeneous, heterogeneous, diffused tumors and synthetic images (non-MR benchmark images). Remarkable results are obtained in segmenting homogeneous tumors of uniform intensity, complex content heterogeneous, diffused tumors on MR images (T1-weighted, postcontrast T1-weighted and T2-weighted) and synthetic images (non-MR benchmark images of varying intensity, texture, noise content and false edges). Further, tumor volume is efficiently extracted from 2-dimensional slices and is named as 2.5-dimensional segmentation. 相似文献
58.
Lycopene is bequeathed with multiple bio-protective roles, primarily attributed to its unique molecular structure. The concomitant exploitation of two of the green chemistry tools viz., sonication and biocatalysis is reported here for the laboratory scale extraction of lycopene from tomato peel. The coupled system improved the extraction by 662%, 225% and 150% times over the unaided, only cellulase ‘Onozuka R-10’ treated and only sonication treated samples respectively. The sonication parameters (duration, cycle and amplitude) during the coupled operation were optimized using response surface methodology (RSM). Derivative UV-visible spectra (i.e., dA/dλ and d2A/dλ2 against λ), FTIR analysis, and DPPH scavenging test suggested that the reported extraction protocol did not affect the molecular structure and bioactivity of the extracted lycopene. The influence of sonication on the probable structural modulation (through UV-visible spectral analysis) and activity of the enzyme were also analyzed. A plausible mechanism is proposed for the enhanced extraction achieved via the coupled system. 相似文献
59.
Hou GL Wen H Lopata K Zheng WJ Kowalski K Govind N Wang XB Xantheas SS 《Angewandte Chemie (International ed. in English)》2012,51(26):6356-6360
Shining light on Zeise: In a study of Zeise's anion, [PtCl(3)(C(2)H(4))](-), and its bromine and iodine analogues, electronic structure information for each species, derived from spectral features, is assigned through calculations at the coupled cluster level of theory. The calculations indicate that the electron binding energies decrease with halogen size and that there is a synergistic η(2) interaction between C(2)H(4) and the PtX(3)(-) anions. 相似文献
60.
Attosecond pump-probe experiments routinely utilize extreme ultraviolet (XUV) and IR fields, with relative phase being the variable parameter. However, the Gouy phase slip between the focused IR and XUV pulses inevitably leads to a certain amount of phase averaging and loss of accuracy. By using ion imaging, we establish a one-to-one mapping between the local phase slip and the spatial coordinates of the focal volume, thus performing in situ characterization of the Gouy phase of a complex beam and its role in ionization of He and Xe. We demonstrate that spatially discriminated ion imaging enhances the contrast of a phase-dependent XUV+IR ionization signal. We utilize our technique to unmask a weak ionization asymmetry, thus opening pathways for further high-precision attosecond studies. 相似文献