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11.
Sudha  N.  Surendran  R.  Jeyaram  S. 《Journal of fluorescence》2022,32(4):1471-1480

This paper presents the synthesis of novel organic compound (E)-N-(3-(3-(4(dimethylamino)phenyl)acryloyl)phenyl)quinolone-2-carboxamide, also known as Quinolinecarboxamide Chalcone (QCC) using aldol condensation and carboxamide formation method. The organic sample QCC was examined by FT-IR, 1H NMR, 13C NMR and mass spectroscopic techniques, respectively. Linear and third-order nonlinear optical (TNLO) properties of QCC dissolved in polar solvents such as DMSO, DMF and Ethanol have also been studied. The order of nonlinear refractive index and nonlinear absorption coefficient of QCC was measured to be 10?11 m2/W and 10?5 m/W. The nonlinear refractive index (n2) of QCC was attributed to negative nonlinearity due to self-defocusing effect, and nonlinear absorption coefficient (β) indicates the behaviors of saturable absorption (SA) and reverse saturable absorption (RSA). The real and imaginary features of the TNLO susceptibility (χ(3)) of QCC in polar solvents were calculated to be the order of 10─7 esu. The spectral characteristics of solvent on TNLO susceptibility of QCC were discussed. The results divulged that the synthesized organic compound is a novel nonlinear optical (NLO) material for applications in photonics and optoelectronics.

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12.
Biosynthesis of silver nanoparticles has received considerable attention due to their cost-effective, eco-friendly and medicinal values. In this study, silver nanoparticles (Ag NPs) were synthesised using the aqueous leaf extracts of Piper nigrum. TEM images revealed that the particle is spherical with 20–50 nm in size. Furthermore, to evaluate the toxicity of synthesized Ag NPs, fish Labeo rohita were exposed to two different concentrations (2.5 µg/L as the treatment I and 5 µg/L as treatment II) for 35 days, and antioxidant parameters and histology of gill, liver and kidney were examined. A biphasic response in the activity of glutathione S-transferases (GST) was observed in gill and liver of fish. GST activity in the kidney of fish was significantly increased when compared to control group. Glutathione reductase (GR) activity in organs/tissue of fish were found to be increased while peroxidase (POD) activity was significantly decreased. Histopathological changes such as hyperplasia, proliferation of epithelial cells and fusion of lamellae were observed in both the concentrations. In liver, necrosis, nuclear degeneration and dilation of sinusoids were observed. Subsequently, the representative effects of POD activity were assessed based on the Box–Behnken Equation, 3-D contour plot and ANOVA analysis through response surface methodology analysis.  相似文献   
13.
Abstract

We describe here a novel technique which makes use of the photothermal mirage effect to study phase transition in liquid crystals. Results of the measurements done with two nematic liquid crystals are given to illustrate this technique. We observe an enhancement in the signal amplitude during phase change which is due to the large magnitude of the refractive index gradient developing at the transition temperature.  相似文献   
14.
In this article we study the max domains of attraction of distributions of sums of independent random variables belonging to the max domains of attraction of max stable laws under linear normalization. These results lead to the study of the max domains of attraction of distributions of products of independent random variables belonging to the max domain of attraction of max stable laws under power normalization.  相似文献   
15.
Automation is being accepted for control systems onboard ships in view of the shortage of skilled manpower in marine sector. Control theory has long been applied to maneuvering problems and at present this trend is continuing at an increased rate. This is for speed control, course control and path keeping. Heading control and course keeping are very important for surface ships while they enter shallow water regions. A typical situation is the entry of a large commercial ship into the harbour basin. The ship faces a sudden change of forces and moments around it due to the change in the hydrodynamics. The Master of the ship regulates the speed while entering the basin. Forces and moments, due to the hydrodynamic flow around the moving hull, are balanced by the rudder behind it. The feed back from the heading angle is taken and the gain in the control system prompts the steering gear to turn the rudder. The conventional control algorithm based on PID is attempted in the first part of the paper and case studies are shown for a Mariner class ship whose hydrodynamic derivatives are known. Displacement, velocities and accelerations are determined for short duration from the simulation of a voyage in calm water. The proposed system can be implemented into autopilot systems. The codes developed in MATLAB can accommodate wind and wave forces as well. The simulation is of a general type and can be used for other vessels with a change in the constants of P (Proportional), I (Integral) and D (Derivative) which can be arrived at by trial and error. The design of the control system depends on the choice of the three control constants Kp, Ki and Kd. These will change as per sea state and extra loads. The control of motions in shallow water and deep water cases are discussed in the paper.  相似文献   
16.
17.
正A homologous series of heterocycles,6-methyl-2-(4-alkoxybenzylidenamino)benzothiazoles,were synthesized and characterized using FT-IR,~1H and ~(13)C NMR and mass spectrometric analysis.Enantiotropic nematic phase was observed for shorter members.Smectic A phase only emerged from octyloxy derivative onwards.The terminal methyl group at the benzothiazole fragment and the Schiff base linkage influenced the mesomorphic behavior of the present series.  相似文献   
18.
The synthesis and characterisation of a series of new rod-shaped liquid crystal (LC), 2-(4-alkyloxybenzylidenamino)benzothiazoles possessing even number of carbon atoms at the alkyloxy chain (CnH2n?+?1O-, n = 2, 4, 6, 8, 10, 12, 14, 16, 18) are reported. The molecular structures of title compounds were elucidated using FTIR and nuclear magnetic resonance spectroscopic techniques. The phase behaviour of these new compounds was characterised and studied by differential scanning calorimetry and polarising optical microscopy. Lower members (n = 2, 4 and 6) did not exhibit mesophase. Octyloxy derivative was monotropic LC. Enantiotropic smectic A phase was observed from n-decyloxy derivatives onward to the last homologous synthesised.  相似文献   
19.
A series of new calamitic liquid crystals 2-[4-(4-alkyloxybenzoyloxy)-phenyl]benzothiazoles comprising a benzothiazole core, terminal alkyl chain and an ester linkage were synthesised and characterised. This series consists of 13 members, wherein the members differ by the length of alkyloxy chain (C n H2n+1O?, where n?=?2–10, 12, 14, 16, 18). Their mesomorphic properties were studied by using differential scanning calorimetry, optical polarising microscopy and powder X-ray diffraction techniques. Enantiotropic nematic phase was present throughout the series, i.e. from the lowest member (n?=?2) until the highest member (n?=?18) of the series. The smectic A phase emerged from the nonyloxy derivative onwards.  相似文献   
20.
Reacting MoO2(acac)2 with Ph2POOH or Me2POOH in EtOH results in the formation of the tetranuclear molybdenum (V) clusters Mo4(μ 3-O)4(μ-O2PR2)4O4, PR2 = PPh2, 1, or PMe2, 2, in functional yields (>90% and 55% respectively). The reaction of WO2(acac)2 with Ph2POOH in MeOH affords the tungsten dimer [(CH3O)2(O)W(μ-O)(μ-O2PPh2)2W(O)(CH3O)2], 3. The single crystal X-ray determined structures of complexes 1–3 are reported. In 1 and 2, the four Mo=O units are interconnected by four triply bridging oxygen atoms, resulting in a distorted cubic-like structure for the Mo4(μ 3-O)4O4 units. Each molybdenum atom forms two additional Mo–O bonds with two oxygen atoms from different adjacent phosphinato ligands. Complex 3, a tungsten dimer, contains packing disorder and consists of bridging oxo and diphenylphosphinato ligands. The bonding of 1 and 2 assessed by density-functional methods showed that bonding between the Mo(V) centers occurs through σ overlap of the d xy orbitals. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Dedicated to the memory of Professor F. A. Cotton. Veritas numquam perit.  相似文献   
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