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21.
Structural Chemistry and Magnetic Properties of Ho3+‐β″‐Al2O3(Ho0, 5Mg0, 5Al10, 5O17) The crystal structure of Ho3+‐β″‐Al2O3(Ho0, 5Mg0, 5Al10, 5O17) was determined by single crystal X‐ray diffraction methods at room temperature (trigonal, R3¯m, Z = 3, a = 561.43(12) pm, c = 3353.7(11) pm). The structural chemical results are correlated with magnetic measurements, where ligand field calculations applying the angular overlap model have been taken into account. 相似文献
22.
Laser induced fluorescence spectra of HoS have been obtained using a Broida oven and a ring dye laser. Dispersed fluorescence spectra showed transitions from a common upper state, A[14.79]8.5 to the v = 0 and 1 vibrational levels of three low lying states, labelled X8.5, W[0.25]7.5 and V[0.98]7.5 (the states are labelled [10−3T0]Ω according to their energy and Ω assignment). High resolution excitation spectra were obtained for all six transitions and a rotational analysis yielded the following principal constants, in cm−1, for the X, W and V states, respectively: T0 = 0, 251.8713(31), 980.6969(37); Be = 0.121903(42), 0.121729(37), 0.122561(34); ΔG1/2 = 463.8811(46), 462.9411(45), 461.2084(127). For the A state, T0 = 14794.6987(28) cm−1 and B0 = 0.112596(29) cm−1. The three low lying states are shown to arise from the Ho2+[4f10(5I8)6s]S2− configuration in accord with Ligand Field Theory predictions. The atomic origin of each of the three low lying electronic states was determined from the observed resolved hyperfine structure. 相似文献
23.
In this work, highly photocatalytically active Ho2O3-SiO2 nanocomposites have been designed and applied for decomposition of methylene blue pollutant. Ho2O3-SiO2 nanocomposites have been produced by new, quick and facile sonochemical process with the aid of tetramethylethylenediamine as a novel basic agent for the first time. The effect of the kind of basic agent, ultrasonic time and dosage of Ho source on the grain size, photocatalytic behavior and shape of the Ho2O3-SiO2 nanocomposites have been evaluated for optimization the production condition. FESEM, EDX, FT-IR, DRS, XRD and TEM have been applied to characterize the as-produced Ho2O3-SiO2 nanocomposites. Use of the as-produced Ho2O3-SiO2 nanocomposites as photocatalyst via destruction of methylene blue pollutant under UV illumination has been compared. It was observed that SiO2 has notable impact on catalytic activity of holmium oxide photocatalyst for destruction. Introducing of SiO2 to holmium oxide can enhance destruction efficiency of holmium oxide to methylene blue pollutant under ultraviolet light. 相似文献
24.
The study of two different methods to obtain strontium barium niobate nanocrystals immersed in a glass matrix has been carried out. Ho2O3-doped SrO-BaO-Nb2O5-B2O3 glasses were fabricated using the melt quenching method. Glass ceramic samples were obtained from the precursor glass by thermal treatment in a furnace and by laser irradiation. These glass ceramic samples are formed by a glassy phase and a crystalline phase of strontium barium niobate nanocrystals. This structure was confirmed by X-ray diffraction and Atomic Force Microscope images. The incorporation of Ho3+ ions in the strontium barium niobate nanocrystals were corroborated by optical measurements, which produced an increment in the luminescence intensity compared to the precursor glass. 相似文献
25.
Infrared (IR) absorption spectra of HoFe3(BO3)4 crystal have been obtained in spectral range 30–7000 cm−1 at temperatures from 4 to 423 K. Vibrational frequencies have been simulated with ‘Lady’ software package both for high-temperature and low-temperature phases. The experimental spectra have been analyzed on the basis of calculated data, and interpreted within the framework of internal vibrations of ionic complexes of HoFe3(BO3)4 crystal lattice. The spectral range under study was observed to have no Davydov splitting of internal vibrational modes due to unit cell multiplication. No effects of magnetic ordering on the IR spectra of the crystal under study were observed in the low-temperature range. 相似文献
26.
27.
Yingjie Zhang Inna Karatchevtseva Linggen Kong Jason R. Price Nicholas Scales Stephen Deen 《Journal of Coordination Chemistry》2017,70(12):2040-2051
Two new holmium (Ho) oxalato complexes have been synthesized under hydrothermal conditions and structurally characterized. [Ho(OH)2]2(C2O4) (1) has a 3-D structure with Ho-(μ3-OH) hydroxide layers connected by μ4-bridging oxalate ligands forming a unique hybrid structure. Sr(H2O)4[Ho(C2O4)2(H2O)]2·2H2O (2) has a 3-D structure built through μ2-bridging oxalate ligands connecting hexagonal Ho oxalate layers with hydrated Sr2+ ions in the channels. Different oxalate ligand arrangements around the metal ions control the structural alterations among the lanthanoid double oxalates even with similar formulas. Both structures have been discussed and compared to the existing lanthanoid oxalato complexes. In addition, their vibration modes, thermal stabilities, electronic structures, and magnetic properties have been further investigated and reported. Both 1 and 2 show the deviation of the magnetic behaviors from the Curie–Weiss law due to the crystal field effects. 相似文献
28.
Holmium doped cadmium lead borate glasses were prepared from melting in appropriate proportions of a mixture of CdO, PbO2, H3BO3 and (1–2 mol %) Ho2O3 in the temperature range of 800–850 °C. The density of glass samples was measured using Archimedes Principle. The infrared spectra of the glasses in the range of 400–4000 cm?1 showed their structure systematically. No boroxol ring formation was observed in the structure of these glasses, but the conversion of 3-fold to 4-fold coordination of boron atoms in the structure of glasses was observed. The glass transition studies were done through differential scanning calorimetry. The optical analysis is done by using the Judd–Ofelt theory. 相似文献
29.
Anhydrous Rare-Earth Acetates, M(CH3COO)3 (M = Sm? Lu, Y) with Chain Structures. Crystal Structures of Lu(CH3COO)3 and Ho(CH3COO)3 Single crystals of the anhydrous rare-earth acetates containing lutetium (type 1) and holmium (type 2) were obtained by crystallisation at 120°C from diluted acetic acid solutions of their oxides and cesium acetate. The crystal structures [Lu(CH3COO)3: orthorhombic, a = 825.85(8), b = 1 398.1(2), c = 823.9(1) pm, Vm = 143.24(3) cm3/mol, space group Ccm21 (No. 36), Z = 4, R = 0.035, Rw = 0.030; Ho(CH3COO)3: monoclinic, a = 1 109.1(3), b = 2 916.3(10), c = 786.8(2) pm, β = 131.90(1)°, Vm = 142.58(8) cm3/mol, space group C2/c (No. 15), Z = 8, R = 0.039, Rw = 0.039, Rw = 0.026] were determined from four-circle diffractometer data sets. The structures consist of one-dimensional infinite chains built up by bridging acetate ions. Ho3+ is coordinated by 8 oxygen atoms, whereas Lu3+ has only 7 nearest oxygen neighbours. The chains are stacked parallel to the [001] direction. Isotypic compounds with Tm? Lu (type 1) and Sm? Er, Y (type 2) were prepared as powders and characterized by X-ray powder patterns. Thermoanalytical investigations (DTA, Guinier-Simon technique) of all compounds have shown that there is a first-order phase transition at 180°C (type 2) and in the range of 230–255°C (type 1). The high-temperature phase crystallizes with the known Sc(CH3COO)3 structure (type 0) where the rare earth cations are surrounded by 6 oxygen atoms. In the case of the type 1 compounds the phase transition is reversible. 相似文献
30.
高纯氧化钬的电感耦合等离子体原子发射光谱分析及光谱干扰的校正 总被引:1,自引:0,他引:1
本文提出了以PGS-2型平面光栅摄谱仪与Plasma Therm ICP-5000D射频发生器联用,乙醇溶液预去溶进样方法,直接同时测定高纯氧化钬中5个稀土杂质元素的方法,并讨论了基体浓度对分析方法检出限的影响和光谱干扰及其校正。当样品溶液中稀土总浓度为5mg/ml时,测定下限分别为铽0.003%,镝、铒和铥0.002%,钇0.0003%。其相对标准偏差为2.8%~7.4%。 相似文献