Silica gel-assisted solvothermal production of CdS,Cu_xS (x=1,2) and ZnS with different morphologies

CdS, CuxS (x=1, 2) and ZnS with different morphologies were produced by the solvothermal reactions of M(CH3COO)2·2H2O (M=Cd, Cu and Zn) and NH2CSNH2 in hexane with and without silica gel as a hard template at 200 ℃ for 24 h. The product phases were detected using X-ray diffraction (XRD). Different morphologies were characterized using a scanning electron microscope (SEM). The existence of silica gel in modeling morphologies of the sulfides was characterized using Fourier transform infrared (FTIR) spectrometer. Raman spectra of different products show the vibrations at the same wavenumbers, although they are composed of different morphologies. Photoluminescence (PL) emissions of the corresponding phases with different morphologies are at the same values, but their intensities are increased by template adding.

Photometric analysis and evolutionary stages of the contact binary V2790 Ori

A photometric analysis and evolutionary stages of the contact binary V2790 Ori are presented.The BV RC observations were carried out at the Thai National Observatory. The photometric light curves were fitted to provide fundamental parameters, required to examine evolutionary stages of the binary. The results indicate that V2790 Ori is a W-type contact system with a mass ratio of q = 2.932. The orbital period increase is found at a rate of d P/dt = 1.03×10^-7 d yr^-1. This implies that a rate of mass transfer from the secondary component to the primary one is dm2/dt =6.31×10^-8 M⊙yr^-1. Furthermore, we find that from the detached phase to the contact phase, the amount of mass that the evolved secondary component has lost is 1.188±0.110 M⊙, i.e., mass lost by the system is 0.789±0.073 M⊙and mass transfer to the primary is0.399±0.037 M⊙. Since the time of the first overflow, the angular momentum loss is found to be 72.2% of JFOF, causing the orbit and Roche surface to shrink until the present time.

Microwave-assisted synthesis of CePO_4 nanorod phosphor with violet emission

Monochnic and hexagonal CePO4 nanoparticles and nanorods were successfully synthesized from Ce（NO3）36H2O and Na3PO4 121-120 solu- tions at pH 1-5 by a 180 W microwave radiation for 60 min. The products were characterized by X-ray diffraction （XRD）, Fourier transform infrared （FFIR） spectroscopy, and scanning electron microscopy （SEM）. XRD patterns revealed that the products are hexagonal CePO4 structures at pH 2-5, and monoclinic CePO4 structtLres at pH 1. SEM characterization shows that these products were nanoparticles, short nanorods, and long nanorods, controlled by the pH of the precursor solutions. Optical properties of the nanorods were also investigated by ultraviolet-visible （UV-vis） and photoluminescence （PL） spectroscopy.

Characterization of MnWO_4 with flower-like clusters produced using spray pyrolysis

MnWO4 (huebnerite) with flower-like clusters of nano-plates was produced from the solutions containing MnCl2·4H2O and Na2WO4·2H2O by the 300 ℃ spray pyrolysis. The phase was detected by X-ray diffraction (XRD) and selected area electron diffraction (SAED), and is in accordance with the results characterized using energy dispersive X-ray (EDX) analysis. The flower-like clusters of nano-plates were characterized using scanning and transmission electron microscopes (SEM and TEM), and their parallel lattice planes using a high resolution transmission electron microscope (HRTEM). Vibration spectra of the huebnerite structured products were characterized using Raman and Fourier transform infrared (FTIR) spectrometers. Their photoluminescence (PL) emissions are in the same spectral region at 405-412 nm.

A photometric study of an EW-type binary system: GV Leo

A photometric study of a contact binary system, GV Leo is presented. New observations were done using the B VR filter bands. We find that a revised orbital period is 0.26673171 d and the orbital period of this system is decreasing at a rate of dP/ dt = -4.95 × 10-7 d yr-1. The photometric solutions are fairly well fitted at a mass ratio of q = 0.1879, with a fillout factor of f = 17.74%. The results indicate that there exists mass transfer from the more massive component to the less massive one at a rate of relative mass exchange, 6zl/m = -1.09× 10-7 yr-1. It is possible that this weak- contact system, that shows a decreasing orbital period, may undergo contraction of the inner and outer critical Roche lobes and evolve into a deep-contact binary.

Efficiency enhancement of Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3) perovskite solar cell by surface passivation using iso-butyl ammonium iodide

Efficiency enhancement of Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3) solar cell devices was performed by using iso-butyl ammonium iodide(IBA)passivated on Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3) films.The n-i-p structure of perovskite solar cell devices was fabricated with the structure of FTO/SnO_(2)/Cs_(0.1)(CH_(3)NH_(3))_(0.9)PbI_(3)(FTO,i.e.,fluorine doped tin oxide)and IBA/Spiro-OMeTAD/Ag.The effect of different weights of IBA passivated on Cs-doped perovskite solar cells(PSCs)was systematically investigated and compared with non-passivated devices.It was found that the 5-mg IBA-passivated devices exhibited a high power conversion efficiency(PCE)of 15.49%higher than 12.64%of non-IBA-passivated devices.The improvement of photovoltaic parameters of the 5-mg IBA-passivated device can be clearly observed compared to the Cs-doped device.The better performance of the IBA-passivated device can be confirmed by the reduction of PbI_(2) phase in the crystal structure,lower charge recombination rate,lower charge transfer resistance,and improved contact angle of perovskite films.Therefore,IBA passivation on Cs_(0.1)(CH_(3)NH)_(0.9)PbI_(3) is a promising technique to improve the efficiency of Cs-doped perovskite solar cells.

Generalized uncertainty principle from long-range kernel effects:The case of the Hawking black hole temperature

We prove the existence of an analogy between spatial long-range interactions,which are of the convolution-type introduced in non-relativistic quantum mechanics,and the generalized uncertainty principle predicted from quantum gravity theories.As an illustration,black hole temperature effects are discussed.It is observed that for specific choices of the moment's kernels,cold black holes may emerge in the theory.

CCD photometric investigation of a W UMa-Type binary GSC 0763-0572

A photometric solution of an A-type W UMa binary, GSC 0763-0572, is examined with a revised orbital period. The overcontact degree is found to be f = 40.66%, with a low mass ratio of q = 0.2554. The result demonstrates an un- ambiguous increase in the orbital period with a relative period change of ΔP/P = +5.69 × 10-7 d yr-1. This indicates that GSC 0763-0572 is undergoing a process of mass transfer from the secondary component to the primary one with a rate of relative mass change of Δm1/m = +5.18 × 10-8 yr-1, for a conservative model of mass transfer. We find that GSC 0763-0572 might transform into a rapidly rotating star, if total spin angular momentum increases until it is greater than one-third of the orbital angular momentum, without breaking the contact configuration.

Facile sonochemical synthesis and photocatalysis of Ag nanoparticle/ZnWO4-nanorod nanocomposites

A facile sonochemical method was developed to synthesize metallic Ag spherical nanoparticles on the surface of ZnWO4 nanorods by forming heterostructure Ag/ZnWO4 nanocomposites.The Ag/ZnWO4 nanocomposites were characterized by X-ray powder diffraction (XRD),Fourier transform infrared spectroscopy (FTIR),field emission scanning electron microscopy (FESEM),transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS).The experimental results showed that fcc metallic Ag nanoparticles were supported on surface of monoclinic sanmartinite ZnWO4 nanorods.The Ag 3d3/2 and Ag 3d5/2 peaks have well-separated binding energies of 6.00 eV,certifying the existence of metallic Ag.The Ag/ZnWO4 nanocomposites were evaluated for photodegradation of methylene blue (MB) induced by ultraviolet-visible (UV-Vis) radiation.In this research,heterostructure 10 wt% Ag nanoparticle/ZnWO4-nanorod composites have the highest photocatalytic activity of 99% degradation of MB within 60 min.The increase in photocatalytic activity was the result of photoinduced electrons in conduction band of ZnWO4 that effectively diffused to metallic Ag spherical nanoparticles and the inhibition of electron-hole recombination process.

Sonochemical synthesis and characterization of uniform lanthanide orthophosphate(LnPO_4, Ln=La and Ce) nanorods

Uniform lanthanide orthophosphate （LnPO4, Ln = La and Ce） nanorods were successfully synthesized by a simple ultrasonic irradiation method using lanthanide nitrate salt （Ln（NO3）3-6H2O, Ln = La and Ce） and sodium phosphate （Na3PO4） in aqueous solutions with the pH of 1-3. The products were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, high-resolution transmission electron microscopy （HRTEM）, Fourier transform infrared spectrometer （FT-IR）, and UV-visible （UV-Vis） spectroscopy. In this research, the products are nanorods of monoclinic LaPO4 and hexagonal CePOa structures and the vibration modes of PO4^3-, including the strong peaks at 227 nm for LaPO4, and at 225 and 278 nm for CePO4.

Photoluminescence and photonic absorbance of Ce_2(MoO_4)_3 nanocrystal synthesized by microwave-hydrothermal/solvothermal method

In this research, cerium （III） nitrate hexahydrate （Ce（NO3）3·6H2O） and ammonium molybdate tetrahydrate （（NH4）6Mo7O24·4H2O） with Ce3＋-to-Mo6＋ molar ratio of 2：3 were dissolved in 40 ml different solvents of deionized （DI） water, polyethylene glycol （PEG） and ethylene glycol （EG） to form different solutions which were followed by adjusting pH from the traditional values to 7.0 and 10.0 with 1 mol.L-1 sodium hydroxide （NaOH）. Subsequently, the solutions were processed by 270-W microwave-hydrother- mal/solvothermal method. Phase, morphology, vibrational modes and photonic properties were fully characterized by X-ray powder diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （FTIR）, Raman spectrophotometry, ultraviolet-visible （UV-Vis） absorption and photoluminescence （PL） spectroscopy. The as-synthe-sized products were pure cerium molybdenum oxide （Ce2（MoO4）3） of nanoparticles clustered together as nano- plates in DI water and PEG solvents, and of spindle-like nanoparticles in EG solvent, including the presence of Ce-O-H mode and MoO4 units. The results show that direct energy gaps of the first two have the same value of 2.30 eV, and that of the last is 2.80 eV, including their blue emission at the same wavelength of 488 nm.

Synthesis and characterization of Gd-doped PbMoO_(4) nanoparticles used for UV-light-driven photocatalysis

Gd-doped PbMoO_(4) nanoparticles were prepared by a refluxing method at 80℃ for 2 h.Effect of molar content of Gd dopant on phase,morphology and optical properties was studied.The as-prepared Gddoped PbMoO_(4) samples can be indexed to pure tetragonal PbMoO_(4) phase.The particles size of PbMoO_(4) is decreased with increasing in the molar content of Gd dopant from 15.20±3.04 nm for pure PbMoO_(4) to 8.72±1.53 nm for 5 mol% Gd-doped PbMoO_(4).The absorption of 5 mol% Gd-doped PbMoO_(4) nanoparticles shows red-shift caused by lattice distortion of PbMoO_(4).The photocatalytic performance of 5 mol% Gddoped PbMoO_(4) nanoparticles shows the highest degradation of rhodamine B(RhB) of 97.92% under UV radiation and 67.65% under visible radiation because Gd^(3+) dopant as an electron acceptor plays the role in enhancing the separation of electron-hole pair.

Photocatalytic activity of La-doped ZnO nanostructure materials synthesized by sonochemical method

ZnO nanostructure materials doped with different La contents were synthesized by sonochemical method. The products were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）,transmission electron microscopy（TEM）, Raman spectroscopy, and Fourier transform infrared spectroscopy（FTIR）. In this research, XRD patterns of pure ZnO and La-doped ZnO are specified as hexagonal wurtzite ZnO structure with no detection of La2O3 phase. SEM and TEM characterization revealed the flower shape of pure ZnO built-up from petals of hexagonal prisms with hexagonal pyramid tips. Upon doping with La, the flower-shaped ZnO is broken into individual 1D prism-like nanorods. Photocatalytic activities of the as-synthesized products were determined by measuring the degradation of methylene blue（MB） under ultraviolet–visible（UV） light irradiation.Among them, the 2.0 mol% La-doped ZnO shows better photocatalytic properties than any other products.

Oscillating gravity,non-singularity and mass quantization from Moffat stochastic gravity arguments

In Moffat stochastic gravity arguments, the spacetime geometry is assumed to be a fluctuating background and the gravitational constant is a control parameter due to the presence of a timedependent Gaussian white noise ξ(t). In such a surrounding, both the singularities of gravitational collapse and the Big Bang have a zero probability of occurring. In this communication, we generalize Moffat’s arguments by adding a random temporal tiny variable for a smoothing purpose and creating a white Gaussian noise process with a short correlation time. The Universe accordingly is found to be non-singular and is dominated by an oscillating gravity. A connection with a quantum oscillator was established and analyzed. Surprisingly, the Hubble mass which emerges in extended supergravity may be quantized.

Hydrothermal synthesis and characterization of Dy-doped CeVO_(4) nanorods used for photodegradation of methylene blue and rhodamine B

Pure CeVO_(4) and Dy-doped CeVO_(4) nanorods containing different weight contents of Dy dopant were synthesized by hydrothermal method.Effect of Dy dopant on photodegradation of methylene blue(MB)and rhodamine B(RhB) was evaluated under UV light irradiation within 80 min.Pure CeVO_(4) and Dydoped CeVO_(4) nanorods were characterized by X-ray diffraction(XRD),Raman spectroscopy,transmission electron microscopy(TEM) and UV-visible spectroscopy.In this research,CeVO_(4) nanorods are tetragonal phase with the detection of main peak shift after being doped with Dy.The length of nanorods is deceased from 50 to 200 nm for pure CeVO_(4) to 50-100 nm for 3% Dy-doped CeVO_(4).Photodegradation of MB and RhB by CeVO_(4) nanorods under UV light irradiation is improved by Dy-dopant that plays the role in accepting electrons and reducing electron-hole recombination.MB and RhB solutions degraded by 3% Dy-doped CeVO_(4) nanorods was 94% and 93% within 80 min,respectively.

Sonochemical synthesis,characterization,and magnetic properties of Mn-doped ZnO nanostructures

Mn-doped ZnO samples,Zn_(1-x)Mn_(x)O(x=0,0.01,0.03 and 0.05;mole fraction),were successfully synthesized by sonochemical method.The undoped and Mn-doped Zn O samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and Raman spectroscopy.XRD patterns of all products are identified to hexagonal wurtzite Zn O structure and their three main peaks shift toward lower diffraction angles due to the incorporation of Mn^(2+)into Zn O crystal lattice.The morphologies of Zn_(1-x)Mn_(x)O(x=0,0.01,0.03 and 0.05)were examined by SEM and TEM.The undoped Zn O sample shows large-scale uniform microflowers which are broken into nanorods and nanoparticles by Mn dopant.Their magnetic properties were investigated by a vibrating sample magnetometer at room temperature.The magnetization-applied field behavior of undoped Zn O defines its weak ferromagnetic behavior.The 3 mol%Mn-doped Zn O shows the highest saturation magnetization of 51.73910^(-3)m A·m^(2)·g^(-1),and the 5 mol%Mn-doped Zn O has suppressed ferromagnetic property due to the formation of Mn clusters inside.

Tailoring charge affinity,dielectric property,and band gap of bacterial cellulose paper by multifunctional Ti_(2)NbO_(7)nanosheets for improving triboelectric nanogenerator performance

Transparent,flexible,and high-performance triboelectric nanogenerator(TENG)from nature-derived materials are required for sustainable society development.However,low triboelectricity from natural material is generally observed.Tunable electronic band diagram(EBD)through facile manipulation is one of the efficient methods to promote the TENG output,requiring fundamental,in depth understanding.Herein,we employed the high quality,single crystal-like Ti_(2)NbO_(7)nanosheets(NSs)with dual dielectric and semiconducting properties as filler for bacterial cellulose(BC)-based TENG.Several techniques including X-ray diffraction(XRD),scanning electron microscopy(SEM),atomic force microscopy(AFM),ultraviolet–visible(UV–vis)absorption,energy dispersive X-ray spectroscopy(EDS),and synchrotron radiation X-ray tomographic microscopy(SRXTM)were applied to characterize the long-range structure,microstructure,optical properties,elemental composition,and three-dimensional(3D)distribution of components in the composites.The semi-transparent and flexible 5 vol.%Ti_(2)NbO_(7)NSs/BC preserved the integrity of cellulose,contained well-dispersed nanosheets,reduced optical band gap(4.20 vs.5.75 eV for BC),and increased surface roughness.The dielectric permittivity and conductivity increased with nanosheets content.Adding negatively-charged Ti_(2)NbO_(7)NSs could regulate the charge affinity of BC composite via shifting of Fermi energy over that of Al.It is found that adding 5 vol.%NSs into the BC film improved electrical outputs(~36 V and~8.8μA),which are 2–4 times higher than that of pure BC,even when paired with Al which lies adjacent in triboelectric series.Our work demonstrated the method to enhance BC-based TENG performance through EBD regulation using multifunctional Ti_(2)NbO_(7)NSs.

Photocatalysis of Cd-doped ZnO synthesized with precipitation method

ZnO particles doped with 0 mol%-5 mol% Cd dopant were successfully synthesized by a precipitation method.The as-synthesized products were characterized by thermogravimetric analysis(TGA),differential scanning calorimetry(DSC),X-ray diffraction(XRD),photoluminescence(PL) spectroscopy,Raman spectroscopy,scanning electron microscopy(SEM) coupled with an energydispersive X-ray(EDX) spectroscopy and transmission electron microscopy(TEM).The precursors showed weight loss at 35-700℃ caused by phase transformation and evaporation processes.The as-synthesized products were specified as hexagonal wurtzite ZnO.The crystallite size of ZnO samples doped with 0 mol%-5 mol% Cd gradually increased with the increase in Cd content.The photocatalytic activities of 0 mol%-5 mol% Cd-doped ZnO samples were evaluated through photodecolorization of methylene blue(MB) under ultraviolet(UV) radiation.In this research,ZnO doped with 3 mol% Cd shows the best photocatalytic activity in degrading of MB molecules as much as 89% within 240 min.

EFFECT OF Co_(3)O_(4)NANOPARTICLE ON THE PROPERTY OF BARIUM TITANATE CERAMIC

Effects of the Co_(3)O_(4)nanoparticle on the phase formation,microstructure and dielectric properties of barium titanate ceramics are investigated in this study.Co_(3)O_(4)-doped BaTiO_(3)ceramics were prepared by the conventional mixed oxide method followed by normal sintering in air.Systematic studies of X-ray diffraction(XRD),scanning electron microscopy and dielectric spectroscopy with varying doping levels were performed.The cell parameters,tetragonality and crystallite size of doped ceramics also were calculated from XRD data.Results showed that the single phase of BaTiO_(3)gave no evidence of unwanted peak forms in any of the samples.Cubic phase occurred after adding Co_(3)O_(4)at 0.25 mol%.Various grain sizes and shapes were found in this system.Finally,adding Co_(3)O_(4)in BaTiO_(3)ceramics resulted in shifting of the Curie point to a lower temperature.The composition,x=0.25,showed different dielectric behavior,which related to appearance of the cubic phase and¯ne grain microstructure.