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排序方式: 共有63条查询结果,搜索用时 31 毫秒
1.
This investigation presents the preparation of CeN0.222O0.667F1.333 by a solid-state reaction from a mixture of CeN:CeF3:CeO2 = 1:2:1.5 and its structural investigation. The samples were annealed at 900°C in platinum tubes for different times. The basic structure found by powder neutron diffraction is anion-excess fluorite-related. The unit cell is an orthorhombic distortion of the cubic fluorite cell and has the space group Abm2. The lattice constants are a = 577.71(2) pm, B = 572.76(5) pm, and c = 573.32(6) pm. The structure refined by Rietveld analysis shows that [1:0:2]- defect clusters are present. In samples prepared by longer annealing times an ordering of these clusters to larger aggregates, i.e., toward the vernier phases, was observed. This was deduced from full profile analysis without refining a structural model by comparing the instrumental resolution curves of several models. 相似文献
2.
Bettina Schweda Dr. Matiss Reinfelds Jakob Hofinger Georg Bäumel Dr. Thomas Rath Dr. Petra Kaschnitz Prof. Dr. Roland C. Fischer Prof. Dr. Michaela Flock Prof. Dr. Heinz Amenitsch Prof. Dr. Markus Clark Scharber Prof. Dr. Gregor Trimmel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(23):e202200276
A series of non-fullerene acceptors based on perylene monoimides coupled in the peri position through phenylene linkers were synthesized via Suzuki-coupling reactions. Various substitution patterns were investigated using density functional theory (DFT) calculations in combination with experimental data to elucidate the geometry and their optical and electrochemical properties. Further investigations of the bulk properties with grazing incidence wide angle X-ray scattering (GIWAXS) gave insight into the stacking behavior of the acceptor thin films. Electrochemical and morphological properties correlate with the photovoltaic performance of devices with the polymeric donor PBDB-T and a maximum efficiency of 3.17 % was reached. The study gives detailed information about structure–property relationships of perylene-linker-perylene compounds. 相似文献
3.
Blaschke Daniel N. Grosse Harald Kronberger Erwin Schweda Manfred Wohlgenannt Michael 《The European Physical Journal C - Particles and Fields》2010,69(3-4):575-579
The European Physical Journal C - Motivated by the success of the non-commutative scalar Grosse–Wulkenhaar model, a non-commutative U ⋆(1) gauge field theory including an... 相似文献
4.
Anna K. Migglautsch Melissa Willim Bettina Schweda Anton Glieder Rolf Breinbauer Margit Winkler 《Tetrahedron》2018,74(43):6199-6204
Microbial cytochrome P450 enzymes (CYPs) are able to mimic the metabolism of human CYPs. One challenge is to identify the respective drug metabolites and to compare substrate specificities to those of the human enzymes. In this study, a class VIII self-sufficient CYP from Aspergillus fumigatus (CYP505X) and variants of this enzyme were heterologously expressed in E. coli. The substrate scope of the variants was determined using active pharmaceutical ingredients (APIs) and (hetero)cyclic compounds. Capsaicin – the active compound in chili peppers – was oxidized most efficiently (4.36?μM/min) in a whole cell mediated biotransformation. The products were isolated, purified and their structures elucidated by 1D and 2D NMR. The two major metabolites showed modifications on the lipophilic side chain. Specifically, capsaicin was hydroxylated at position 8 to give (E)-8-hydroxy-N-(4-hydroxy-3-methoxybenzyl)-8-methylnon-6-enamide and epoxidized at the double bond to give N-(4-hydroxy-3-methoxybenzyl)-5-(3-isopropyloxiran-2-yl)-pentanamide. 相似文献
5.
6.
Linda Schweda 《Journal of organometallic chemistry》2010,695(18):2076-2082
The reaction of α,β-unsaturated imines with [(1,5-cyclooctadiene)-bis(2-methylallyl)-ruthenium(II)] leads to the formation of mononuclear ruthenium complexes of the general formula {(COD)Ru[RNC(H)-C(H)C(Ph)]2}. In these complexes the imine ligands are deprotonated in β-position with respect to the imine double bond and coordinate as an enyl-imino ligand. In the case of R = Me, Et the corresponding compounds have been characterized by X-ray crystallography. The relevance of these complexes with respect to ruthenium catalyzed C-C coupling reactions of the same α,β-unsaturated imines is demonstrated by the structural analysis of another mononuclear ruthenium complex in which two imine ligands are reductively coupled (R = Cy). [(1,5-Cyclooctadiene)-bis(2-methylallyl)-ruthenium(II)] also turns out to be a highly effective precatalyst in the reaction of the respective imines with carbon monoxide and ethylene to produce heterocyclic compounds. 相似文献
7.
A.A. Bichl J.M. Grimstrup H. Grosse E. Kraus L. Popp M. Schweda R. Wulkenhaar 《The European Physical Journal C - Particles and Fields》2002,24(1):165-176
We show that the non-commutative Yang–Mills field forms an irreducible representation of the (undeformed) Lie algebra of
rigid translations, rotations and dilatations. The non-commutative Yang–Mills action is invariant under combined conformal
transformations of the Yang–Mills field and of the non-commutativity parameter . The Seiberg–Witten differential equation results from a covariant splitting of the combined conformal transformations and
can be computed as the missing piece to complete a covariant conformal transformation to an invariance of the action.
Received: 6 November 2001 / Published online: 5 April 2002 相似文献
8.
J.M. Grimstrup H. Grosse E. Kraus L. Popp M. Schweda R. Wulkenhaar 《The European Physical Journal C - Particles and Fields》2002,24(3):491-494
In this letter we apply the methods of our previous paper, hep-th/0108045, to noncommutative fermions. We show that the fermions
form a spin-1/2 representation of the Lorentz algebra. The covariant splitting of the conformal transformations into a field-dependent
part and a -part implies the Seiberg-Witten differential equations for the fermions.
Received: 5 December 2001 / Published online: 22 May 2002 相似文献
9.
The supersymmetric structure of the Becchi-Rouet-Stora invariance is used for investigating the Abelian Higgs-Kibble model. It allows for a symmetric photon mass M, in which case a massless scalar state corresponding to the Goldstone model belongs to the physical sector. If M = 0, i.e. the photon mass is generated by the Higgs mechanism, this state is decoupled from the physical sector, as usual. The BPHZ renormalization procedure is used. 相似文献
10.
In this Letter we call into question the perturbatively parity breakdown at 1-loop for the massless QED3 frequently claimed in the literature. As long as perturbative quantum field theory is concerned, whether a parity anomaly owing to radiative corrections exists or not shall be definitely proved by using a renormalization method independent of any regularization scheme. Such a problem has been investigated in the framework of BPHZL renormalization method, by adopting the Lowenstein–Zimmermann subtraction scheme. The 1-loop parity-odd contribution to the vacuum-polarization tensor is explicitly computed in the framework of the BPHZL renormalization method. It is shown that a Chern–Simons term is generated at that order induced through the infrared subtractions — which violate parity. We show then that, what is called “parity anomaly”, is in fact a parity-odd counterterm needed for restauring parity. 相似文献