Compton profiles of NiO and TiO_2 obtained from first principles GWA spectral function

In this work,we first use momentum density studies to understand strongly correlated electron behavior,which is typically seen in transition metal oxides.We observe that correlated electron behavior as seen in bulk NiO is due to the Fermi break located in the middle of overlapping spectral functions obtained from a GW（G is Green’s function and W is the screened Coulomb interaction） approximation（GWA） calculation while in the case of TiO2 we can see that the origin of the constant momentum distribution in lower momenta is due to a pile up of spectra before the Fermi energy.These observations are then used to compare our calculated Compton profiles with previous experimental studies of Fukamachi and Limandri.Our calculations for NiO are observed to follow the same trend as the experimental profile but it is seen to have a wide difference in the case of TiO2 before the Fermi break.The ground state momentum densities differ significantly from the quasiparticle momentum density,thus stressing the importance of the quasiparticle wave function as the input for the study of charge density and the electron localization function.Finally we perform a calculation of the quasiparticle renormalization function,giving a quantitative description of the discontinuity of the GWA momentum density.

Anisotropic transport of microalgae Chlorella vulgaris in microfluidic channel

In this work, we study the regional dependence of transport behavior of microalgae Chlorella vulgaris inside microflu- idic channel on applied fluid flow rate. The microalgae are treated as spherical naturally buoyant particles. Deviation from the normal diffusion or Brownian transport is characterized based on the scaling behavior of the mean square displacement （MSD） of the particle trajectories by resolving the displacements in the streamwise （flow） and perpendicular directions. The channel is divided into three different flow regions, namely center region of the channel and two near-wall boundaries and the particle motions are analyzed at different flow rates. We use the scaled Brownian motion to model the transitional characteristics in the scaling behavior of the MSDs. We find that there exist anisotropic anomalous transports in all the three flow regions with mixed sub-diffusive, normal and super-diffusive behavior in both longitudinal and transverse directions.

Measuring gravitational effect of superintense laser by spin-squeezed Bose-Einstein condensates interferometer

We consider an extremely intense laser,enclosed by an atom interferometer.The gravitational potential generated from the high-intensity laser is solved from the Einstein field equation under the Newtonian limit.We compute the strength of the gravitational force and study the feasibility of measuring the force by the atom interferometer.The intense laser field from the laser pulse can induce a phase change in the interferometer with Bose-Einstein condensates.We push up the sensitivity limit of the interferometer with Bose-Einstein condensates by spin-squeezing effect and determine the sensitivity gap for measuring the gravitational effect from intense laser by atom interferometer.

Fabrication and Characterization of a 2×2 Microfiber Knot Resonator Coupler

A 2×2 microfiber knot resonator(MKR)coupler is demonstrated.The hybrid device is obtained by forming a knot within the coupling region of a microfiber coupler with a 50:50 splitting ratio.The microfiber coupler is successfully fabricated by laterally fusing and tapering two optical fibers using a flame-brushing technique.The coupler has an overlapping length of 40 mm with a uniform waist of around 5μm.With an MKR structure,the coupler produces a resonant response at both output ports.The free spectral range of the output spectrum from both ports is obtained at 0.2 nm at a knot diameter of 260μm.The resonance extinction ratio of the device varies from 2 to 6 dB while the calculated Q factor and finesse are~25646 and 3.3,respectively,at both output ports.

Performance Comparison of Mode-Locked Erbium-Doped Fiber Laser with Nonlinear Polarization Rotation and Saturable Absorber Approaches

A mode-locked erbium-doped fiber laser (EDFL) is demonstrated using a highly concentrated erbium-doped fiber (EDF) as the gain medium in a ring configuration with and without a saturable absorber (SA).Without the SA,the proposed laser generates soliton pulses with a repetition rate of 12 MHz,pulse width of 1.11 ps and energy pulse of 1.6pJ.By incorporating SA in the ring cavity,the optical output of the laser changes from soliton to stretched pulses due to the slight change in the group velocity dispersion.With the SA,a cleaner pulse is obtained with a repetition rate of 11.3 MHz,a pulse width of 0.58ps and a pulse energy of 2.3pJ.

Dynamic Control of Tunneling Conductance in Ferroelectric Tunnel Junctions

We investigate the dynamic characteristics of electric polarization P(t)in a ferroelectric junction under ac applied voltage and stress,and calculate the frequency response and the cut-off frequency f0,which provides a reference for the upper limit of the working frequency.Our study might be significant for sensor and memory applications of nanodevices based on ferroelectric junctions.

Methodical review of the literature referred to the dye-sensitized solar cells: Bibliometrics analysis and road mapping

This study presents a systematic review of the literature pertaining to dye-sensitized solar cells(DSSCs), in order to anticipate the direction and speed of change in technology trend. To study the general progression in DSSC research, we have assessed the evolution in annual DSSCs publications and their citations. Further, in order to identify the intellectual bases, we have also classified the journals, authors, institutes, and countries according to their scientific productivity in the field of DSSCs research during the period of 2007–2017.

Selection of radio astronomical observation sites and its dependence on human generated RFI

We investigate the influence of population density on radio-frequency inter- ference （RFI） affecting radio astronomy. We use a new method to quantify the thresh- old of population density in order to determine the most suitable lower limit for site selection of a radio quiet zone （RQZ）. We found that there is a certain trend in the population density-RFI graph that increases rapidly at lower values and slows down to almost fiat at higher values. We use this trend to identify the thresholds for pop- ulation density that produce RFI. Using this method we found that, for frequencies up to 2.8 GHz, low, medium and high population densities affecting radio astronomy are below 150 ppl km-2, between i50 ppl km-2 and 5125 ppl km-~, and above 5125 ppl km-2 respectively. We also investigate the effect of population density on the environment of RFI in three astronomical windows, namely the deuterium, hydro- gen and hydroxyl lines. We find that a polynomial fitting to the population density produces a similar trend, giving similar thresholds for the effect of population density. We then compare our interference values to the standard threshold levels used by the International Telecommunication Union within these astronomical windows.

Characteristics of LiNiPO_4 Prepared by Chitosan Polymer Precursor Method

1 Results Stoichimetric quantities of lithium acetate,nickel acetate and ammonium dihydrogen phosphate were mixed with ethanol and stirred with heating until complete dissolution.A solution of 1 g chitosan in 1% acetic acid was then poured into the heated and stirred solution until all solvents have evaporated.The precursor was then sintered at 500,600,700,800,900 and 1 000 ℃ for 3 hours.X-ray diffraction results showed that single phase LiNiPO4 was obtained at sintering temperatures above 600 ℃.TEM res...

Characterization of vanadyl phthalocyanine based surface-type capacitive humidity sensors

This study presents the fabrication and characterization of novel surface-type capacitive humidity sensors using vanadyl phthalocyanine（VOPc） as the active material.The devices,which comprise three different thicknesses, have been fabricated using the thermal evaporation technique.A thin film of VOPc is deposited on thoroughly cleaned glass substrates with pre-patterned Ag electrodes.The capacitive effect of the samples under humidity has been investigated. Comparison of the samples with different thicknesses shows that the thinnest device seems more sensitive towards humidity.The humidity dependent capacitance properties of the sensor make it beneficial for use in commercial hygrometers.

Nanosecond Pulses Generation with Samarium Oxide Film Saturable Absorber

Nanosecond pulse generation is demonstrated in a mode-locked erbium-doped fiber laser(EDFL) utilizing a samarium oxide(Sm2O3) film. The Sm2O3 film exhibits a modulation depth of 33%, which is suitable for modelocking operation. The passively pulsed EDFL operates stably at 1569.8 nm within a pumping power from 109 to 146 m W. The train of generated output pulses has a pulse width of 356 nm repeated at a fundamental frequency of 0.97 MHz. The average output power of 3.91 m W is obtained at a pump power of 146 m W, corresponding to 4.0 nJ pulse energy. The experimental result indicates that the proposed Sm2O3 saturable absorber is viable for the construction of a flexible and reliably stable mode-locked pulsed fiber laser operating in the 1.5 m region.

Synthesis of α-Mo_2C by Carburization of α-MoO_3 Nanowires and Its Electrocatalytic Activity towards Tri-iodide Reduction for Dye-Sensitized Solar Cells

Nanowire-shaped α-Mo O3 was synthesized on a large scale by hydrothermal route.Nanocrystalline α-Mo2 C phase was obtained by the carburization of α-Mo O3 nanowires with urea as a carbon source precursor.The phase purity and crystalline size of the synthesized materials were ascertained by using powder X-ray diffraction.The shape and morphology of synthesized materials were characterized by field-emission scanning electron microscopy（FE-SEM） and high resolution transmission electron microscopy（HR-TEM）.The electrocatalytic activity of α-Mo2 C for I-/I3^-redox couple was investigated by the cyclic voltammetry.The synthesized α-Mo2 C was subsequently applied as counter electrode in dye-sensitized solar cells to replace the expensive platinum.

Studies on the Dielectric and Transport Properties of PEO/Chitosan Proton Conducting Polymer Electrolyte

1 Results The effect of ammonium nitrate (NH4NO3) content in 40 wt.% PEO and 60 wt.% chitosan blend has been analyzed in this study.The sample containing 40 wt.% NH4NO3 exhibited the highest room temperature conductivity.In order to ascertain that water does not influence the conductivity,the samples were dried in a dessicator and the conductivity determined daily until it shows a constant value.Results are as shown in Fig.1.Samples containing other salt concentrations were also kept in the dessicator f...

Tin stearate organometallic precursor prepared SnO_2 quantum dots nanopowder for aqueous- and non-aqueous medium photocatalytic hydrogen gas evolution

Current study reports a rapid one-pot non-hydrolytic condition in the synthesis of Sn O2QDs nanopowder using tin(II) stearate(Sn(St)2) as environmentally-benign organometallic precursor,which is an unprecedentedly employed-compound in preceding Sn O2nanopowder productions.The as-synthesized Sn O2QDs that are hydrophobic can be easily transferred from organic solvent to aqueous solution through a robust ligand exchange method.The stearate-capping ligands on the surface of QDs can be replaced by beta-cyclodextrin(β-CD) and eventually render the QDs highly water soluble,which ultimately make it exhibit bi-functionality for different liquid medium applications.Structural characterizations reveal that the bi-functional QDs are indeed well-matched with the standard rutile Sn O2cassiterite phase without the presence of any impurities.The QDs can be interchangeably used as photocatalyst for both aqueous and non-aqueous phase,where it shows significant enhancement of hydrogen gas production as compared to that of commercial Sn O2nanopowder.

Analysis of the energy spectra of ground states of deformed nuclei in the rare-earth region

The 62Sm, 64Gd, 66Dy, 70Yb, 72Hf and 74W nuclei are classified as deformed nuclei. Low-lying bands are one of the most fundamental excitation modes in the energy spectra of deformed nuclei. In this paper a theoretical analysis of the experimental data within the phenomenological model is presented. The energy spectra of ground states are calculated. It is found that the low-lying spectra of ground band states are in good agreement with the experimental data.

A Partial Double-Pass S-Band Erbium-Doped Fibre Amplifier

An efficient and low noise short wavelength band erbium-doped fibre amplifier （S-band EDFA） is proposed and demonstrated using double-pass configuration. This amplifier provides a gain of 1500 nm signal as high as 26.9 dB, which is 9.6 dB higher than the two-stage single-pass amplifier. The corresponding noise figure obtained is 7.5 dB, which is of the same level as in the single-pass amplifier and more than 2 dB lower than the previously reported double-pass amplifier [IEIOE Electron. Express 2 （2005） 182]. The gain enhancement is due to the double pass-propagation of the test signal in the second stage, which increases the effective erbium-doped fibre （EDF） length. The low noise is attributed to the optical circulator between EDFs, which prevents the backward amplified spontaneous emission from propagating into the input part of the amplifier. The proposed amplifier is expected to play an important role in the development of a practical S-band EDFA.

A Q-Switched Erbium-Doped Fiber Laser with a Carbon Nanotube Based Saturable Absorber

We demonstrate a simple,compact and low cost Q-switched erbium-doped fiber laser(EDFL)using single-wall carbon nanotubes(CNTs)as a saturable absorber for possible applications in metrology,sensing,and medical diagnostics.The EDFL operates at around 1560 nm with repetition rates of 16.1 kHz and 6.4 kHz with saturable absorbers SA1 and SA2 at a pump power of 120 mW.The absorbers are constructed by optically driven deposition and normal deposition techniques.It is observed that the optical deposition method produces a Q-switched EDFL with a lower threshold of 70 mW and better Q-switching performance compared to that of the normal deposition method.The EDFL also has pulse energy of 90.3 nJ and pulse width of 11.6μs at 120 mW pump power.

Zinc-oxide nanoparticle-based saturable absorber deposited by simple evaporation technique for Q-switched fiber laser

A Q-switched erbium-doped fiber laser(EDFL)incorporating zinc-oxide(ZnO)nanoparticles-based saturable absorber(SA)is proposed and demonstrated.To form the SA,the ZnO nanoparticles,which are originally in the powder form,are first dissolved in ethanol and subsequently deposited onto the surface of fiber ferrule by using the adhesion effect with the evaporation technique.By integrating the ZnO nanoparticle-based SA into a laser cavity of an EDFL,a self-started and stable Q-switching is achieved at a low threshold power of 20.24 mW.As the pump power is increased,the pulse repetition rate is tunable from 10.34 kHz to 25.59 kHz while pulse duration decreases from 21.39μs to 3.65μs.Additionally,this Q-switched laser has a maximum energy per pulse of 19.34 nJ and an average output power of 0.46 mW.These results indicate the feasibility and functionality of the ZnO nanoparticles-based SA for Q-switched generation,which offers the flexibility and easy integration of the SA into a ring laser cavity.

Poly(Acrylamide-Co-Acrylic Acid)-Zinc Acetate Polymer Electrolytes: Studies Based on Structural and Morphology and Electrical Spectroscopy

Solid polymer electrolytes (SPEs) of polyacrylamide-co-acrylic acid (PAA) as the polymer host and zinc acetate (ZnA) as an ionic dopant were prepared using a single solvent by the solution casting technique. The amorphous and crystalline structures of film were investigated by X-ray diffraction (XRD). The surface morphology of samples was examined by scanning electron microscopy (SEM). The composition and complex formation of films were characterized by Fourier transform infrared (FTIR) spectroscopy. The conductivity of the PAA-ZnA films was determined by electrochemical impedance spectroscopy. According to the XRD and FTIR analyses, all electrolyte films were in amorphous state and the existence of interaction between Zn2+ cations and the PAA structure confirms that the film was successfully prepared. The SEM observations reveal that the electrolyte films appeared to be rough and flat with irregularly shaped surfaces. The highest ionic conductivity (σ) of 1.82 × 10-5 Scm-1 was achieved at room temperature (303 K) for the sample containing 10 wt % ZnA.

Prediction of moment of inertia of rotating nuclei

In this study,the mathematical expression formulated by Bohr for the moment of inertia of even-even nuclei based on the hydrodynamical model is modified.The modification pertains to the kinetic energy of the surface oscillations,including the second and third terms of the R-expansion as well as the first term,which had already been modified by Bohr.Therefore,this work can be considered a continuation and support of Bohr's hydrodynamic model.The procedure yields a Bohr formula to be multiplied by a factor that depends on the deformation parameter.Bohr's(modified)formula is examined by applying it on axially symmetric even-even nuclei with atomic masses ranging between 150 and 190 as well as on some triaxial symmetry nuclei.In this paper,the modification of Bohr's formula is discussed,including information about the stability of this modification and the second and third terms of the R-expansion in Bohr's formula.The results of the calculation are compared with the experimental data and Bohr's results recorded earlier.The results obtained are in good agreement with experimental data,with a ratio of approximately 0.7,and are better than those of the unmodified ones.