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31.
Debajyoti Choudhury Rahul Sinha S Arunagiri Gautam Bhattacharyya Debrupa Chakraverty Debajyoti Choudhury Amitava Datta Anindya Datta Aseskrishna Datta Amol Dighe Dilip Kumar Ghosh Anjan Giri Stephen King Anirban Kundu Rukmani Mohanta Biswarup Mukhopadhyaya Sreerup Raychaudhuri Saurabh Rindani Probir Roy DP Roy Sourov Roy AI Sanda Nita Sinha Rahul Sinha K Sridhar H Yamamoto 《Pramana》2000,55(1-2):335-345
This report summarises the work done during WHEPP-6 (Institute of Mathematical Sciences, Chennai, India, Jan 3–15, 2000) in
Working group on ‘B and collider physics’. 相似文献
32.
Nita H. Shah Mrudul Y. Jani Urmila Chaudhari 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2018,24(1):1-11
In competitive edge, the proffer of delay payment is of great consequence tool to boost the market demand by exerting influence of more customers. In opposition to, merchandiser may be asked to pay some per cent of purchasing cost before receiving products to reduce the risk of cancellation of order. In this article, optimal replenishment time for merchandiser under partial upstream prepayment and partial downstream overdue payment is presented under quadratic demand with three different models: (1) without deterioration, (2) with constant deterioration and (3) maximum fixed-lifetime deterioration as loss of utility is the real situation of products like fruits, vegetables, juices, etc., and to reduce deterioration of the product, merchandiser spends capital on preservation technology to preserve the item. Quadratic demand is suitable for the products for which demand increases initially and afterward it starts to decrease. The decision policies are analysed for the merchandiser. The objective is to minimize merchandiser’s total cost with respect to decision variables. The models are supported with numerical examples. Sensitivity analysis is carried out to derive insights for decision maker. 相似文献
33.
O. A. Dumitru R. Cs. Begy D. C. Nita L. D. Bobos C. Cosma 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(2):1335-1339
In this paper a simple method was used to design and set up an electrodeposition device for uranium source preparation for alpha spectrometry measurements. The aim of this work is to find the optimal parameters to be used to achieve uranium alpha sources with good spectral properties and maximum yield of the electrodeposition process. Samples with specific uranium activity were prepared from aqueous solution of uranyl nitrate hexahydrate (UO2 (NO3)2·6H2O). A series of preliminary experiments was conducted to establish the main parameters that have a significant influence on the deposition efficiency. Among these, the electrodeposition time was studied and the optimum time was found to be 1 h, in the case of our home-made deposition cell. It was also shown that a current of 1,500 mA, plating time of 60 min and pH range of 2–2.2 are the best conditions for deposition of uranium. The alpha spectrometry results show a good spectral resolution for the uranium sources obtained by the electrodeposition using the optimal parameters. 相似文献
34.
Small molecule‐mediated control of hydroxyapatite growth: Free energy calculations benchmarked to density functional theory
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Zhijun Xu Yang Yang Ziqiu Wang Donald Mkhonto Cheng Shang Zhi‐Pan Liu Qiang Cui Nita Sahai 《Journal of computational chemistry》2014,35(1):70-81
The unique, plate‐like morphology of hydroxyapatite (HAP) nanocrystals in bone lends to the hierarchical structure and functions of bone. Proteins enriched in phosphoserine (Ser‐OPO3) and glutamic acid (Glu) residues have been proposed to regulate crystal morphology; however, the atomic‐level mechanisms remain unclear. Previous molecular dynamics studies addressing biomineralization have used force fields with limited benchmarking, especially at the water/mineral interface, and often limited sampling for the binding free energy profile. Here, we use the umbrella sampling/weighted histogram analysis method to obtain the adsorption free energy of Ser‐OPO3 and Glu on HAP (100) and (001) surfaces to understand organic‐mediated crystal growth. The calculated organic‐water–mineral interfacial energies are carefully benchmarked to density functional theory calculations, with explicit inclusion of solvating water molecules around the adsorbate plus the Poisson–Boltzmann continuum model for long‐range solvation effects. Both amino acids adsorb more strongly on the HAP (100) face than the (001) face. Growth rate along the [100] direction should then be slower than in the [001] direction, resulting in plate‐like crystal morphology with greater surface area for the (100) than the (001) face, consistent with bone HAP crystal morphology. Thus, even small molecules are capable of regulating bone crystal growth by preferential adsorption in specific directions. Furthermore, Ser‐OPO3 is a more effective growth modifier by adsorbing more strongly than Glu on the (100) face, providing one possible explanation for the energetically expensive process of phosphorylation of some proteins involved in bone biomineralization. The current results have broader implications for designing routes for biomimetic crystal synthesis. © 2013 Wiley Periodicals, Inc. 相似文献
35.
Usha Chandra Prerana Mudgal Manoj Kumar Rajeev Rawat G. Parthasarathy Nita Dilawar A. K. Bandyopadhyay 《Hyperfine Interactions》2005,163(1-4):129-141
We report here the Mössbauer measurements on nanocrystalline perovskite structured manganite La0.8Sr0.2Mn0.8Fe0.19
57Fe0.01O3 as a function of pressure up to 10 GPa at room temperature. The nanocrystalline sample, prepared by sol–gel technique found to have crystallite sizes of ∼138 ± 10 Å. Zero-field electrical resistivity measurements with temperature support the nanocrystalline nature. At ambient pressure, Fe3+ as well as Fe4+ ions are distributed in two different environments – Fe3+ in low symmetric site surrounded by Mn3+ ions only while Fe4+ in high symmetric site with at least one Mn3+ ion. Pressure seems to affect the higher symmetric site. A sudden increase in isomer shift at 0.52 GPa indicates the first order phase transition representing the transformation of Fe4+ to Fe3+. Another transition at 3.7 GPa, represents the presence of Fe3+ in single kind of environment. Pressure dependence of electrical resistivity measurements verifies the transitions attributing the first order transition to the cross over of localized-electron to band magnetism. 相似文献
36.
The importance of substrate chemistry and structure on supported phospholipid bilayer design and functionality is only recently being recognized. Our goal is to investigate systematically the substrate-dependence of phospholipid adsorption with an emphasis on oxide surface chemistry and to determine the dominant controlling forces. We obtained bulk adsorption isotherms at 55 degrees C for dipalmitoylphosphatidylcholine (DPPC) at pH values of 5.0, 7.2, and 9.0 and at two ionic strengths with and without Ca(2+), on quartz (alpha-SiO(2)), rutile (alpha-TiO(2)), and corundum (alpha-Al(2)O(3)), which represent a wide a range of points of zero charge (PZC). Adsorption was strongly oxide- and pH-dependent. At pH 5.0, adsorption increased as quartz < rutile approximately corundum, while at pH 7.2 and 9.0, the trend was quartz approximately rutile < corundum. Adsorption decreased with increasing pH (increasing negative surface charge), although adsorption occurred even at pH > or = PZC of the oxides. These trends indicate that adsorption is controlled by attractive van der Waals forces and further modified by electrostatic interactions of oxide surface sites with the negatively charged phosphate ester (-R(PO(4)-)R'-) portion of the DPPC headgroup. Also, the maximum observed adsorption on negatively charged oxide surfaces corresponded to roughly two bilayers, whereas significantly higher adsorption of up to four bilayers occurred on positively charged surfaces. Calcium ions promote adsorption beyond a second bilayer, regardless of the sign of oxide surface charge. We develop a conceptual model for the structure of the electric double layer to explain these observations. 相似文献
37.
David Brardan Sylvain Franger Diana Dragoe Arun Kumar Meena Nita Dragoe 《固体物理学:研究快报》2016,10(4):328-333
Entropic contributions to the stability of solids are very well understood and the mixing entropy has been used for forming various solids, for instance such as inverse spinels, see Nawrotsky et al., J. Inorg. Nucl. Chem. 29 , 2701 (1967) [1]. A particular development was related to high entropy alloys by Yeh et al., Adv. Eng. Mater. 6 , 299 (2004) [2] and Cantor et al., Mater. Sci. Eng. A 375–377 , 213 (2004) [3] (for recent reviews see Zhang et al., Prog. Mater. Sci. 61 , 1 (2014) [4] and Tsai et al., Mater. Res. Lett. 2 , 107 (2014) [5]) in which the configurational disorder is responsible for forming simple solid solutions and which are thoroughly studied for various applications especially due to their mechanical properties, e.g. Gludovatz et al., Science 345 , 1153 (2014) [6] and Lu et al., Sci. Rep. 4 , 6200 (2014) [7], but also electrical properties, Kozelj et al., Phys. Rev. Lett. 113 , 107001 (2014) [8], hydrogen storage, Kao et al., Int. J. Hydrogen Energy 35 , 9046 (2010) [9], magnetic properties, Zhang et al., Sci. Rep. 3 , 1455 (2013) [10]. Many unexplored compositions and properties still remain for this class of materials due to their large phase space. In a recent report it has been shown that the configurational disorder can be used for stabilizing simple solid solutions of oxides, which should normally not form solid solutions, see Rost et al., Nature Commun. 6 , 8485 (2015) [11] these new materials were called ”entropy‐stabilized oxides”. In this pioneering report, it was shown that mixing five equimolar binary oxides yielded, after heating at high temperature and quenching, an unexpected rock salt structure compound with statistical distribution of the cations in a face centered cubic lattice. Following this seminal study, we show here that these high entropy oxides (named HEOx hereafter) can be substituted by aliovalent elements with a charge compensation mechanism. This possibility largely increases the potential development of new materials by widening their (already complex) phase space. As a first example, we report here that at least one HEOx composition exhibits colossal dielectric constants, which could make it very promising for applications as large‐k dielectric materials. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
38.
We propose a new method to determine the mass and width differences of the two D meson mass eigenstates as well as the CP violating parameters associated with D0-D[over ]0 mixing. We show that an accurate measurement of all the mixing parameters is possible for an arbitrary CP violating phase, by combining observables from a time dependent study of D decays to a doubly Cabibbo suppressed mode with information from a CP eigenstate. As an example we consider D0-->K*0pi0 decays where the K*0 is reconstructed in both K+pi- and K(S)pi0. We also show that decays to the CP eigenstate D-->K+K- together with D-->K+pi- decays can be used to extract all the mixing parameters. There is a fourfold ambiguity in the solutions for x and y in both the cases. A combined analysis using D0-->K*0pi0 and D-->K+K- can also be used to reduce the ambiguity in the determination of parameters. 相似文献
39.
Singhal Sunil Kumar Srivastava Avanish Kumar Dilawar Nita Gupta Anil Kumar 《Journal of nanoparticle research》2010,12(6):2201-2210
Journal of Nanoparticle Research - We report an effective approach to synthesize boron nitride (BN) nanotubes having novel morphologies employing a mechanothermal process. In this process, a... 相似文献
40.
Singh Jasveer Kumaraswamidhas L. A. Sharma Nita Dilawar 《Accreditation and quality assurance》2019,24(2):105-112
Accreditation and Quality Assurance - This paper reports the evaluation of the measurement uncertainty of the pressure distortion coefficient (λ) of a piston gauge using the Monte Carlo method... 相似文献