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排序方式: 共有138条查询结果,搜索用时 15 毫秒
21.
22.
Perez Barrio J Rebilly JN Carter B Bradshaw D Bacsa J Ganin AY Park H Trewin A Vaidhyanathan R Cooper AI Warren JE Rosseinsky MJ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(15):4521-4532
Substitution of the pillaring ligand in the homochiral open-framework [Ni(2)(L-asp)(2)(bipy)] by extended bipy-type ligands leads to a family of layer-structured, homochiral metal-organic frameworks. The 1D channel topology can be modified by the nature of the organic linker, with shape, cross-section and the chemical functionality tuneable. In addition, the volume of these channels can be increased by up to 36 % compared to the parent [Ni(2)(L-asp)(2)(bipy)]. The linker 1,4-dipyridylbenzene (3rbp) gives access to a new layered homochiral framework [Ni(2)(L-asp)(2)(3rbp)] with channels of a different shape. In specific cases, non-porous analogues with the linker also present as a guest can be activated to give porous materials after sublimation. Their CO(2) uptake shows an increase of up to 30 % with respect to the parent [Ni(2)(L-asp)(2)(bipy)] framework. 相似文献
23.
Two L-proline based homochiral frameworks synthesised via diffusion and solvothermal methods display distinct L-proline bonding modes, one N,O chelating and one O,O bridging with amine nitrogen not bound to the metal, with binding mode dependent upon the degree of protonation of the amino acid. 相似文献
24.
25.
MJ Singh DO Kataria N Madhavan P Sugathan JJ Das DK Awasthi AK Sinha R Shanker 《Pramana》1999,53(4):743-764
A projectile ion-recoil ion coincidence technique has been employed to study the multiple ionization and the charge transfer
processes in collisions of 60–120 MeV Si
q+ (q = 4−14) ions with neutral argon atoms. The relative contribution of different ionization channels, namely; direct ionization,
electron capture and electron loss leading to the production of slow moving multiply charged argon recoil ions have been investigated.
The data reported on the present collision system result from a direct measurement in the considered impact energy for the
first time. The total ionization cross-sections for the recoil ions are shown to scale as q
1.7/E
p
0.5
, where E
p is the energy in MeV of the projectile and q its charge state. The recoil fractions for the cases of total- and direct ionizations are found to decrease with increasing
recoil charge state j. The total ionization fractions of the recoils are seen to depend on q and to show the presence of a ‘shell-effect’ of the target. Further, the fractions are found to vary as 1/j
2 upto j = 8+. The average recoil charge state 〈j〉 increases slowly with q and with the number of lost or captured electrons from or into the projectile respectively. The projectile charge changing
cross-sections σ
qq′ are found to decrease with increasing q for loss ionization and to increase with q for direct-and capture ionization processes respectively. The physics behind various scaling rules that are found to follow
our data for different ionization processes is reviewed and discussed. 相似文献
26.
27.
Richard M. Ibberson Dr. Amelia J. Fowkes Dr. Matthew J. Rosseinsky Prof. William I. F. David Prof. Peter P. Edwards Prof. 《Angewandte Chemie (International ed. in English)》2009,48(8):1435-1438
Metal lite : High‐resolution neutron powder diffraction data reveals that the body‐centered cubic crystal structure of lithium(0)tetraamine transforms to a simple cubic structure below 22 K. The detailed structure determinations will allow new insights into the coupled structural and electronic properties of the lightest metal.
28.
Li MR Adem U McMitchell SR Xu Z Thomas CI Warren JE Giap DV Niu H Wan X Palgrave RG Schiffmann F Cora F Slater B Burnett TL Cain MG Abakumov AM van Tendeloo G Thomas MF Rosseinsky MJ Claridge JB 《Journal of the American Chemical Society》2012,134(8):3737-3747
Combining long-range magnetic order with polarity in the same structure is a prerequisite for the design of (magnetoelectric) multiferroic materials. There are now several demonstrated strategies to achieve this goal, but retaining magnetic order above room temperature remains a difficult target. Iron oxides in the +3 oxidation state have high magnetic ordering temperatures due to the size of the coupled moments. Here we prepare and characterize ScFeO(3) (SFO), which under pressure and in strain-stabilized thin films adopts a polar variant of the corundum structure, one of the archetypal binary oxide structures. Polar corundum ScFeO(3) has a weak ferromagnetic ground state below 356 K-this is in contrast to the purely antiferromagnetic ground state adopted by the well-studied ferroelectric BiFeO(3). 相似文献
29.
AK Peacock SI Cauët A Taylor P Murray SR Williams JV Weaver DJ Adams MJ Rosseinsky 《Chemical communications (Cambridge, England)》2012,48(75):9373-9375
Poly[2-(methacryloyloxy)ethylphosphorylcholine]-coated SPIONs were prepared through ATRP and amidation coupling reactions. The coated SPIONs exhibited high stability and re-dispersability in phosphate buffered saline and uptake in a stem cell line, with high T(2) relaxivity. 相似文献
30.
Surface spline interpolation when the domain is all of Rd isknown to converge much faster to the data function f than inthe case when the domain is the unit ball. This difference isunderstood to be due to boundary effects which, as will be shown,also affect the size of the surface spline's coefficients. Wepropose a modified form of surface spline interpolation which,to a great extent, overcomes these boundary effects. This modifiedsurface spline interpolant uses only the values of f at thegiven interpolation points. 相似文献