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排序方式: 共有57条查询结果,搜索用时 31 毫秒
41.
T. Gamze Ulusoy Ghobadi Prof. Ekmel Ozbay Prof. Ferdi Karadas 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(11):3638-3649
Prussian blue (PB) and its analogues (PBAs) have at least a three-century-long history in coordination chemistry. Recently, cobalt-based PBAs have been acknowledged as efficient and robust water oxidation catalysts. Given the flexibility in their synthesis, the structure and morphology of cobalt-based PBAs have been modified for enhanced catalytic activity under electrochemical (EC), photocatalytic (PC), and photoelectrochemical (PEC) conditions. Here, in this review, the work on cobalt-based PBAs is presented in four sections: i) electrocatalytic water oxidation with bare PBAs, ii) photocatalytic processes in the presence of a photosensitizer (PS), iii) photoelectrochemical water oxidation by coupling PBAs to proper semiconductors (SCs), and iv) the utilization of PBA-PS assemblies coated on SCs for the dye-sensitized photoelectrochemical water oxidation. This review will guide readers through the structure and catalytic activity relationship in cobalt-based PBAs by describing the role of each structural component. Furthermore, this review aims to provide insight into common strategies to enhance the catalytic activity of PBAs. 相似文献
42.
Roaming dynamics have been observed in a three-dimensional model of the ketene isomerization reaction. The roaming trajectories sample the region between the outer potential barriers closest to the respective ketene isomers and involve turning points along the reaction coordinate in a polar representation. These roaming trajectories avoid the intrinsic reaction coordinate and the intermediates to which it is associated. Thus, one-dimensional transition state theory (TST) is generally insufficient as has been confirmed through an analysis of the reactive flux along the dividing surface (DS). A global representation of the DS, however, leads to accurate TST rate constants. The exact and TST microcanonical rates of isomerization have been obtained for the three-dimensional model and compare well to experiment. The global DS is therefore particularly important for obtaining rates in reactions that exhibit roaming. This work thus confirms the findings of our previous two-dimensional treatment of ketene isomerization (Ulusoy et al. in J. Phys. Chem. A 117:7553–7560, 2013). 相似文献
43.
In the present paper, we prove quantitative q‐Voronovskaya type theorems for q‐Baskakov operators in terms of weighted modulus of continuity. We also present a new form of Voronovskaya theorem, that is, q‐Grüss‐Voronovskaya type theorem for q‐Baskakov operators in quantitative mean. Hence, we describe the rate of convergence and upper bound for the error of approximation, simultaneously. Our results are valid for the subspace of continuous functions although classical ones is valid for differentiable functions. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
44.
The main goal of this paper is to introduce Durrmeyer modifications for the generalized Szász–Mirakyan operators defined in (Aral et al., in Results Math 65:441–452, 2014). The construction of the new operators is based on a function \(\rho \) which is continuously differentiable \(\infty \) times on \( \left[ 0,\infty \right) ,\) such that \(\rho \left( 0\right) =0\) and \( \inf _{x\in \left[ 0,\infty \right) }\rho ^{\prime }\left( x\right) \ge 1.\) Involving the weighted modulus of continuity constructed using the function \( \rho \), approximation properties of the operators are explored: uniform convergence over unbounded intervals is established and a quantitative Voronovskaya theorem is given. Moreover, we obtain direct approximation properties of the operators in terms of the moduli of smoothness. Our results show that the new operators are sensitive to the rate of convergence to f, depending on the selection of \(\rho .\) For the particular case \(\rho \left( x\right) =x\), the previous results for classical Szász-Durrmeyer operators are captured. 相似文献
45.
46.
Fatih Doğan Mahmut Ulusoy Ömer F. Öztürk İsmet Kaya Bekir Salih 《Journal of Thermal Analysis and Calorimetry》2009,98(3):785-792
Several mononuclear Co(II), Ni(II), Cu(II), and Fe(II) complexes of tetradentate salpren-type diimine, obtained from 3,5-di-tert-butyl-2-hydroxybenzaldehyde and 1,3-diaminopropane have been prepared and characterized by analytical, spectroscopic (FT-IR,
UV–VIS) techniques, magnetic susceptibility measurements and thermogravimetric analyses (TG). The thermodynamic and thermal
properties of complexes have been investigated. For further characterization Direct Insertion Probe-Mass Spectrometry (DIP-MS)
was used and the fragmentation pattern and also stability of the ions were evaluated. The characterization of the end products
of the decomposition was achieved by X-ray diffraction. The thermal stabilities of metal complexes of N,N′-bis(3,5-di-t-butylsalicylidene)-1,3-propanediamine ligand (L) were found as Ni(II) > Cu(II) > Co(II) > Fe(II). 相似文献
47.
Halil İbrahim Ulusoy Ramazan Gürkan Öznur Yılmaz Mehmet Akçay 《Journal of Analytical Chemistry》2012,67(2):131-139
A sensitive and selective method has been developed for the determination of chromium in water samples based on using cloud
point extraction (CPE) preconcentration and determination by flame atomic absorption spectrometry (FAAS). The method is based on the complexation of Cr(III) ions with Brilliant Cresyl Blue (BCB) in the presence of non-ionic surfactant Triton X-114. Under the optimum conditions, the preconcentration of 50 mL of water
sample in the presence of 0.5 g/L Triton X-114 and 1.2 × 10−5 M BCB permitted the detection of 0.42 μg/L chromium(III). The calibration graph was linear in the range of 1.5–70 μg/L, and
the recovery of more than 99% was achieved. The proposed method was used in FAAS determination of Cr(III) in water samples
and certified water samples. In addition, the developed CPE-FAAS method was also used for speciation of the inorganic chromium
species after reduction of Cr(VI) to Cr(III) using a thiosulphate solution of 120 mg/L in the presence of Hg(II) ion as a
stabilizer. 相似文献
48.
Fahir Talay Akyildiz Salih Tatar Suleyman Ulusoy 《Mathematical Methods in the Applied Sciences》2013,36(17):2397-2402
This paper analyzes the existence and the uniqueness problem for an n‐dimensional nonlinear inverse reaction‐diffusion problem with a nonlinear source. A transformation is used to obtain a new inverse coefficient problem. Then, a parabolic differential operator Lλ is defined to establish the relation between the solution of Lλ = 0 and the new inverse problem. Following this, it is shown that the inverse problem has at least one solution in the class of admissible coefficients. Furthermore, it is proved that this solution is the unique solution of the undertaken inverse problem. A numerical example is given to illustrate ill‐posedness of the inverse problem. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
49.
Nuray Ulusoy Muammer Kiraz ?mer Kü?ükbasmac? 《Monatshefte für Chemie / Chemical Monthly》2002,20(3):1305-1315
New 4-alkyl/aryl-1-((6-(4-bromophenyl)-imidazo[2,1-b]thiazol-3-yl)-acetyl)-3-thiosemicarbazides and 3-alkyl/aryl-2-(((6-(4-bromophenyl)-imidazo[2,1-b]thiazol-3-yl)-acetyl)-hydrazono)-4-thiazolidinones were synthesized from 6-(4-bromophenyl)-imidazo[2,1-b]thiazole-3-acetic acid hydrazide. Their structures were elucidated by elemental analyses and spectroscopic data. All compounds were tested for antibacterial and antifungal activities. The antimicrobial activities of the compounds were assessed by the microbroth dilution technique. The compounds were also evaluated for antituberculosis activity against Mycobacterium tuberculosis H37Rv (ATCC 27294); they exhibited varying degrees of inhibition in the in vitro primary screening at 6.25 μg · cm−3. The most active compound was 3-(4-nitrophenyl)-2-(((6-(4-bromophenyl)-imidazo[2,1-b]thiazol-3-yl)-acetyl)-hydrazono)-4-thiazolidinone. 相似文献
50.