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31.
Let R be a ring, A = M n (R) and θ: AA a surjective additive map preserving zero Jordan products, i.e. if x,yA are such that xy + yx = 0, then θ(x)θ(y) + θ(y)θ(x) = 0. In this paper, we show that if R contains \frac12\frac{1}{2} and n ≥ 4, then θ = λϕ, where λ = θ(1) is a central element of A and ϕ: AA is a Jordan homomorphism.  相似文献   
32.
火焰原子吸收法测定钼精矿中的钼、铜   总被引:5,自引:1,他引:4  
本文研究了和火焰原子吸收法测定钙精矿中钼、铜的方法,确定了两种元素最佳仪器工作条件,对共存元素的干扰及消除进行了研究,该方法快速、简便,对实际样品进行了测定,获得满意结果。  相似文献   
33.
火焰原子吸收法测定大洋底锰结核中的铜,钴,镍,铁,锰   总被引:1,自引:0,他引:1  
本文介绍了用火焰原子吸收法对大洋底锰结核中铜,镍,铁、锰中五种离子同时测定的方法。确定了仪器工作条件,并对共存元素及残留试剂的影响进行了研究。方法精密度和准确度令人满意。  相似文献   
34.
The bare M and ligand-protected nanoparticles M(25)(SR) and M(13)(PR)(10)Cl (M = Au, Ag, Cu) are investigated using the density functional theory. There are strong interactions between the metal core atoms and the ligands. It is found that the electronic structures agree well with the Jellium model for gold and copper nanoparticles. The superatoms's S and P orbitals are shown. However for silver ones, as the adding of the ligands, the S orbital of the nanoparticle disappears. The binding energy of these nanoparticles are also obtained by our calculation. The Au nanoparticles are most stable, the Cu ones take second place, and the Ag ones are the third stable. Our results could be essential for further understanding of the properties of ligand-protected isolated superatoms.  相似文献   
35.
A new protonated borophosphate (H3O)Mg(H2O)2[BP2O8]·H2O ( 1 ) was synthesized under mild hydrothermal conditions and characterized by single‐crystal X‐ray diffraction, FTIR spectroscopy and TG‐DTA. The compound crystallizes in the hexagonal system, space group P6(1)22 (No 178), a = 9.4462(7) Å, c = 15.759(2) Å, V = 1217.8(2) Å3, and Z = 6. There exist infinite helical $^1_\infty$ {[BP2O8]3–} ribbons built up from corner‐sharing PO4 and BO4 tetrahedra, which are connected by MgO4(H2O)2 leading to an infinite three‐dimensional open‐framework. The H3O+ ions are located at the free thread of the helical ribbons, whereas crystallized water occupy the channels of the helical ribbons. The dehydration of the compound occurs at a higher temperature which is presumably due to the anisotropic hydrogen bonds in the crystal structure. The luminescent properties of the compound were studied.  相似文献   
36.
本文合成了一系列含有胆固醇和4-(反式-正烷基环己基)苯甲酸结构单元的新型双液晶基元液晶化合物。这些化合物中两个介晶基元是利用不同长度的氧烷酰基连接在一起。利用FT-IR、MS、1H NMR、POM、DSC 表证了所得化合物的结构和介晶性,并选择几种双液晶基元液晶测定了它们的机械黏度和在主体液晶中的螺旋扭曲力(HTP)。结果表明,绝大多数化合物显示较低相变温度的胆甾相(N*),并且被选择的化合物的平均机械黏度和螺旋扭曲力类似于或优于胆甾醇任酸酯。  相似文献   
37.
Adamantane and its derivatives have been introduced into many drugs for current clinical research and some of them are used tor tlie treatment of neurological disease and/or used as the antiviral agents as well as the agents against type-2 diabetes.Recently,there have been many relevant research reported for developing medicinal chemistry by employing the adamantyl group.In this paper,a new adamantane-based compound (3-phenyl-adamantane-1-carboxylic acid,PACA) was synthesized and characterized by X-ray diffraction(XRD), themiogravimeric analysis(TGA),Fourier transtomi infrared spectroscopy(FTIR),etc.,which should be a beneficial complement or extension to the existing adamantyl-based materials.  相似文献   
38.
Chitosan (CS) decorated reduced graphene oxide‐Ferrocene nanocomposite (RGO?Fc?CS) was synthesized by a one‐pot reaction. In the synthesis process of RGO?Fc?CS, GO?Fc was successfully self‐assembled via the π–π interaction, which had the features of large surface area and the high load. Then GO‐Fc and CS linked via one‐pot under alkaline conditions. The FT?IR, TGA, SEM were employed to characterize the successful synthesis of RGO?Fc?CS composites. A miniature electrochemical system was fabricated by RGO?Fc?CS modified glassy carbon electrode (expressed as RGO?Fc?CS/GCE) for the sensitive detection of RhB enantiomers via DPV. Electrochemical results revealed that the RGO?Fc?CS/GCE exhibited high molecular recognition toward RhB. Due to the synergy between the RGO?Fc and CS, the RGO?Fc?CS/GCE showed a linear range of 0.001–70 μM with a LOD of 0.5 nM, indicating that RGO?Fc?CS/GCE has broad application prospects to simplify monitor RhB real‐time.  相似文献   
39.
First-principle calculations based on density functional theory have been performed on the nonmagnetic 2p light element C-doped ZnO thin films. The total energies and magnetism of the system are calculated with a ten-layer slab along () direction. The results show that the C-doped ZnO thin films are ferromagnetic. A single C is preferable to occupy the subsurface site. As the concentration of C atoms increases, the ferromagnetic coupling among the dopants is more favorable, and they tend to form a cluster around the Zn atom at the film surface. The ferromagnetism is predicted to be mainly from a p-d exchange-like p-p coupling interaction and a p-d exchange hybridization. The p-p coupling interaction is the dominative mechanism.  相似文献   
40.
Three-primary-color luminescent materials are highly desirable to construct white-light emitting resource,multi-color optical displays,and tunable photonic applications.However,the efficient strategy to establish the three-primary-color systems with unique photofunctionalities is still rather limited,particularly for molecular materials.Herein,we developed a molecular cocrystal route to obtain three-primary-color emissive materials by tuning different donor-acceptor units based on the same chromophore(4,4′-bis(2,5-dimethylstyryl)biphenyl,Bdb).The warm and cold white-light together with multi-color emission in most of visible region can be highly adjusted by rationally tuning different mixture components of three-primary-color cocrystals through an energy transfer mechanism.Furthermore,the blue/green/red emitters endow Bdb molecular cocrystals novel colortunable photonic properties(such as one-dimensional(1D)/2D optical waveguide,polarized fluorescence,up-conversion luminescence,and amplified spontaneous emission),benefitting from their well-defined micro/nanostructures and high crystallinity.Particularly,the high luminescence quantum yield(82.49%)and polarized anisotropy(0.723)outperform most of state-ofthe-art molecular crystalline materials.Therefore,this work supplies an effective way to fabricate new types of three-primarycolor phosphors through luminescent cocrystals,which have promising applications in the fields of full-color displays,whitelight irradiation,low-dimensional optical polarization,and micro/nanophotonics.  相似文献   
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