Polycrystalline BiFeO3 and rare earth substituted ***3 （BRFO, R=Y, Ho and Er） compounds were prepared by rapid solid state sintering technique. Structural phase analysis indicated that all the compounds stabilized i...
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Polycrystalline BiFeO3 and rare earth substituted ***3 （BRFO, R=Y, Ho and Er） compounds were prepared by rapid solid state sintering technique. Structural phase analysis indicated that all the compounds stabilized in rhombohedral structure （R3c space group） and a small orthorhombic phase fraction was observed in BRFO compounds. From the Raman spectra results, the changes in the phonon frequencies （A1） and line widths suggested lattice distortion in the BRFO compounds as was evidenced in the XRD analysis. Compared to the linear variation of magnetization with magnetic field （M-H） shown by BFO, an obvious M-H loop was observed in BRFO compounds which could be due to the suppression of space modulated spin structure and was explained on the basis of weak ferromagnetism and field induced spin reorientation. UV-Vis spectroscopy evidenced a change in local FeO6 envi- ronment due to shift in the 6Alg→4T2g energy transition band. BRFO compounds with improved remnant magnetization and coercive field are applicable for magnetoelectric devices.
A series of red-emitting phosphors of CaBi2Ta2O9：Pr3＋ and CaBi2Ta2O9：Eu3＋ were synthesized by the solid-state reaction method. The crystal structure and photoluminescence properties were investigated by X-ray diff...
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A series of red-emitting phosphors of CaBi2Ta2O9：Pr3＋ and CaBi2Ta2O9：Eu3＋ were synthesized by the solid-state reaction method. The crystal structure and photoluminescence properties were investigated by X-ray diffraction （XRD） and photoluminescence spectra. The emission spectra showed that the red emission peaks were located at 622 nm for Pr3＋ and 615 nm for Eu3＋, respectively. The optimal doping concentrations for Ca1-xBi2Ta2O9：xPr3＋ and Ca1-yBi2Ta2O9：yEu3＋ were x=0.02 and y=0.15, respectively. The effect of fluxes （H3BO3, NH4F, CaCl2 and CaF2） and charge compensations （Li2CO3, Na2CO3 and K2CO3） on luminescent properties were investigated in detail. It was found that the relative emission intensity of Ca0.98Bi2Ta2O9：0.02Pr3＋ with 10 mol.% H3BO3 flux was about 2.9 times higher than that of the sample without flux. The relative emission intensity of Ca0.7Bi2Ta2O9：0.15Eu3＋, 0.15K＋ was about the 2.1 times higher than that of Ca0.85Bi2Ta2O9：0.15Eu3＋.
Cubic boron nitride (c‐BN) is a super‐hard material whose hardness increases dramatically with decreasing size. However, c‐BN nanoparticles (NPs) with sizes less than 10 nm have never been obtained. Herein we repor...
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Cubic boron nitride (c‐BN) is a super‐hard material whose hardness increases dramatically with decreasing size. However, c‐BN nanoparticles (NPs) with sizes less than 10 nm have never been obtained. Herein we report a simple strategy towards the synthesis of ultrafine c‐BN NPs with an average size of 3.5 nm. The method, under ambient conditions, exploits a laser‐induced photochemical effect and employs dioxane solution of ammonia borane (AB) as a liquid target. Meanwhile, total dehydrogenation of AB is realized by laser irradiation. Therefore, this approach shows great potential for the preparation of super‐hard NPs as well as controllable dehydrogenation.
Carpet-like zinc films with unique nanowires are fabricated by using a simple physical evaporation *** definite morphologies of the films endow the superhydrophobic material with a contact angle of about 157.9°,a...
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Carpet-like zinc films with unique nanowires are fabricated by using a simple physical evaporation *** definite morphologies of the films endow the superhydrophobic material with a contact angle of about 157.9°,and by additional modification of CF_(3)(CF_(2))_(7)CH_(2)CH_(2)Si(OCH_(3))_(3)the water adhesive force could be tuned from 58.3μN to 14.6μ*** order to analyze the controllable adhesion of superhydrophobic Zn films,we study the microstructure and chemical compositions of the films by x-ray diffraction SEM,TEM,HRTEM and ***,a model based on the balance of micro-surface energy is proposed to illustrate the relationship of the geometry and wettability properties of the *** model provides new insights into how to design-oriented microchannels and micro-protuberance on material surfaces,which is of benefit for controlling their ability of caught-collection in air bubbles and water-pinning collection.
Aerogels are a low-density, porous, non-crystalline, nanometer solid material,whose continuous network structures can be controlled and tialored by varying the amount of reactants, catalyst and *** fragility and britt...
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Aerogels are a low-density, porous, non-crystalline, nanometer solid material,whose continuous network structures can be controlled and tialored by varying the amount of reactants, catalyst and *** fragility and brittleness, however, are the major drawbacks, which restrict their application in effective ***, the flexibility of aerogels becomes more attractive in the present *** is the most abundant resource in the world and microfibrillated cellulose can be made from all kinds of plants [1].
In this paper, we observe experimentally the optical bistability induced by the side-mode injection power and wave- length detuning in a single mode Fabry-P6rot laser diode （SMFP-LD）. Results show that the bistabili...
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In this paper, we observe experimentally the optical bistability induced by the side-mode injection power and wave- length detuning in a single mode Fabry-P6rot laser diode （SMFP-LD）. Results show that the bistability characteristics of the dominant and injected modes are strongly dependent on the injected input optical power and wavelength detuning in an SMFP-LD. We observe three types of hysteresis loops： counterclockwise, clockwise, and butterfly hysteresis with various loop widths. In the case of a bistability loop caused by injection power, the transition from counterclockwise to clockwise in the hysteresis direction with the wavelength detuning from 0.028 nm to 0.112 nm is observed in a way of butterfly hys- teresis for the dominant mode by increasing the wavelength detuning. The width of hysteresis loop, induced by wavelength detuning is also changed while the injection power is enhanced from -7 dBm to -5 dBm.
A series of silica nanoscale materials（NIMs） were prepared through a facile acid-base neutralization. These silica derivatives consist of a nanosilica core, a charged corana（sulfonic acid SIT） attatched to the cor...
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A series of silica nanoscale materials（NIMs） were prepared through a facile acid-base neutralization. These silica derivatives consist of a nanosilica core, a charged corana（sulfonic acid SIT） attatched to the core, and an oppositely charged canopy （PEG-substituted tertiary amines） to balance the corona. By selecting proper canopy such as surface-functionalized, silica can behave viscous liquid in the absence of any solvent at room temperature. DSC results indicated the melting temperature and glass transition of the derivatives were slightly lower than those of the neat polymer canopy, indicating strong interaction between the core and PEG-substituted tertiary amine.
Optoelectronic applications require materials both responsive to objective photons and able to transfer carriers, so new two‐dimensional (2D) semiconductors with appropriate band gaps and high mobilities are highly d...
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Optoelectronic applications require materials both responsive to objective photons and able to transfer carriers, so new two‐dimensional (2D) semiconductors with appropriate band gaps and high mobilities are highly desired. A broad range of band gaps and high mobilities of a 2D semiconductor family, composed of monolayer of Group 15 elements (phosphorene, arsenene, antimonene, bismuthene) is presented. The calculated binding energies and phonon band dispersions of 2D Group 15 allotropes exhibit thermodynamic stability. The energy band gaps of 2D semiconducting Group 15 monolayers cover a wide range from 0.36 to 2.62 eV, which are crucial for broadband photoresponse. Significantly, phosphorene, arsenene, and bismuthene possess carrier mobilities as high as several thousand cm 2 V −1 s −1 . Combining such broad band gaps and superior carrier mobilities, 2D Group 15 monolayers are promising candidates for nanoelectronics and optoelectronics.
Five lanthanide complexes of Ln2（dpdc）2（tpy）2（NO3）2（H2O）2 [Ln=La （1）, Ce （2）, Pr （3）, Sm （4）, Gd （5）, H2dpdc=2,2’-biphenyldicarboxylic acid and tpy=2,2’：6’,2’’-terpyridine] were prepared at roo...
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Five lanthanide complexes of Ln2（dpdc）2（tpy）2（NO3）2（H2O）2 [Ln=La （1）, Ce （2）, Pr （3）, Sm （4）, Gd （5）, H2dpdc=2,2’-biphenyldicarboxylic acid and tpy=2,2’：6’,2’’-terpyridine] were prepared at room temperature and characterized by X-ray diffraction, FT-IR and thermo-gravimetric analysis. The results showed that complexes 1–5 were isostructural and consisted of dinuclear units [Ln2（dpdc）2（tpy）2（NO3）（H2O）2] bridged by two dpdc2？ ligands. The dinuclear units with strong intramolecular hydrogen bonds were assembled into 2D supramolecular layers by the weak π？？？π staking interactions between pyridine rings of tpy. The TG analysis showed that the complexes 1–5 behaved higher thermal stability with no mass loss at 〈 320 °C. The lanthanide contraction effect and the solid state luminescence properties of complexes 1–5 were also investigated. The luminescence emission spectra of complexes 1–5 exhibited ligands emission bands and complex 3 and 4 had no typical emission in the visible region.
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