Band structure of even-even selenium isotopes in the proton-neutron interacting Boson model

Available systematic IBM calculations [1-6] for Krypton and Strontium isotopes have been extended to Selenium. The analysis in terms of the IBM is complicated by the interplay of collective and noncollective degrees of freedom. However, satisfactory agreement has been obtained forN≦42.     

System design considerations for precision measurement of high magnetic fields by Faraday effect

Practical and technical considerations for an instrument designed to measure high magnetic fields by Faraday effect are given. Magnetic fields up to 2 Tesla were measured and the results compared to those of Nuclear Magnetic Resonance technique. Results of measurements at low temperatures are also reported.     

Surface plasmon resonance and surface-enhanced Raman scattering activity of SiO2–Au core-cap nanostructure arrays

SiO₂–Au core-cap nanostructure arrays were prepared by dip-coating technique combined with wet chemical reduction method. The surface morphologies, structures, and optical properties of the obtained samples were characterized by scanning electron microscopy, X-ray diffraction, and ultraviolet–visible spectrophotometer, respectively. The surface-enhanced Raman scattering (SERS) activity of SiO₂–Au core-cap nanostructure arrays substrates was investigated using leucine as probe molecule. And the relationship between the SERS effect and the surface plasmon resonance (SPR) peaks was discussed. High-quality, stable, and reproducible SERS spectra of leucine were successfully obtained. When the maximum SPR peak matched with the excitation wavelength, the substrate gave rise to the highest SERS enhancement. Furthermore, six different fluorescent dyes were also chosen as probe molecules. It was found that the substrate showed good Raman enhancement and highly efficient fluorescence quenching characteristic on these fluorescent dyes.     

The KLL Auger spectrum of fluorine

The KLL Auger spectrum of fluorine (Z=9) has been studied in three different fluoride salts. Five Auger lines are observed in each compound in accordance with extreme LS coupling theory. A cation dependence of the Auger transition energies and line-widths is observed. The energy shifts are in agreement with a theoretical model.     

Luminescent properties of Eu2+ ions in AlN at low and high intensity of excitation

Luminescent properties of powder AlN∶Eu²⁺ phosphors were studied by excitation of 2-nd harmonic of ruby laser (hv=3·56 eV). It was shown that emission spectra of AlN∶Eu²⁺ phosphors consist of five or two overlapping bands according to the concentration of europium and the intensity of excitation. Decay times of luminescence of Eu²⁺ centres in different peaks lie between 0·9 and 1·5 μsec which is in agreement with the value of decay time of 4f⁶ 5d→47⁷ transition of Eu²⁺ ions. It is evident from the decomposition of emission spectra of Eu²⁺ centres that there exist several types of Eu²⁺ centres in AlN as was already demonstrated in the case of oxygen centres in AlN.     

Optimized AC conductivity correlated to structure,morphology and thermal properties of PVDF/PVA/Nafion composites

Polyvinylidene fluoride (PVDF) and polyvinyl alcohol (PVA) composites were prepared by controlled loading of Nafion (5 to 15 wt%) by solution casting using water and dimethylformamide (DMF) as a solvent. The surface morphology of composite analyzed by atomic force microscopy (AFM) reveals the presence of Nafion ionomers. The increase in interlayer spacing of modified PVDF/PVA polymer system as a function of Nafion was detected by X-ray diffraction (XRD). The major change in Fourier transform infrared (FTIR) spectroscopy confirms the chemical bond C=O stretching around 1,700 cm^?1 due to Nafion. Differential scanning calorimetry (DSC) demonstrates the thermal stability of polymer composites and the decrease in melting temperature (T _m). The optimized AC conductivity (σ) of the prepared composite was evaluated by using an impedance analyzer as a function of temperature (40 to 150 °C) at constant 30-MHz frequency. The highest conductivity of 1.3?×?10^?2 S m^?1 was observed at 80 °C for 10 wt% of Nafion and correlated with structure, morphology and thermal properties of modified PVDF/PVA/Nafion composites. The experimental results may be useful for sensors, fuel cells and battery application domains.     

On the theory of electron diffusion under a temperature gradient in degenerate semiconductors having non-parabolic energy bands

The theory of electron diffusion under a temperature gradient (Soret effect) in degenerate semiconductors having non-parabolic energy bands and spherical constant-energy surfaces is worked out for the first time. An expression is given for the Soret coefficient which may be determined from the knowledge of the energy dependence of the relaxation time and can be related to the thermoelectric power.     

THz photomixer with milled nanoelectrodes on LT-GaAs

A terahertz (THz) photomixer: (i) a meander type antenna with integrated nanoelectrodes on (ii) a low temperature grown GaAs has been fabricated and characterized. It was designed for spectral range of 0.3–0.4 THz where molecular fingerprinting and sensing are performed. By combination of electron beam lithography with post-processing using focused ion beam (FIB), milling the THz emitter was successfully fabricated. Nanogaps as small as 40 nm width in the active area of photomixer were milled by FIB. Nanocontacts enhance electric fields of the illuminated and THz radiation and contribute to a better collection of photo-electrons. THz emission was obtained and spectrally characterized.     

Three-body calculations of elastic Deuteron-helium-4-scattering with faddeev equations

The Faddeev equations are applied to the Deuteron-⁴He system. For the interactions between the particles squarewell potentials are used. In order to solve the Faddeev equations, thet-matrix is approximated by one separable term. The phaseshifts of the elastic Deuteron-⁴He scattering are calculated. It is shown, that the separable approximation by only one term is insufficient for such calculations.     

An in silico protocol for identifying mTOR inhibitors from natural products

The mammalian target of rapamycin (mTOR) is an anti-cancer target. In this study, we propose an in silico protocol for identifying mTOR inhibitors from the ZINC natural product database. First, a three-dimensional quantitative structure–activity relationship pharmacophore model was built based on known mTOR inhibitors. The model was validated with an external test set, Fischer’s randomization method, a decoy set and pharmacophore mapping conformation testing. The results showed that the model can predict the mTOR inhibition activity of the tested compounds. Virtual screening was performed based on the best pharmacophore model, and the results were then filtered using a molecular docking approach. In addition, molecular mechanics/generalized born surface area analysis was used to refine the selected candidates. The top 20 natural products were selected as potential mTOR inhibitors, and their structural scaffolds could serve as building blocks in designing drug-like molecules for mTOR inhibition.     

Surface-enhanced Raman scattering of 4-mercaptobenzoic acid and hemoglobin adsorbed on self-assembled Ag monolayer films with different shapes

Polyvinylpyrrolidone (PVP)-protected silver nanostructures of various shapes, including nanocubes, nanospheres, and hybrid shapes with nanospheres and nanorods, on the surface of glass or Si substrates (PVP-Ag films) are prepared by using electrostatic self-assembly. With 4-mercaptobenzoic acid (4-MBA) as a probe molecule, it is demonstrated that the PVP-protected silver nanocubes films (PVP-Ag NCs) have better surface-enhanced Raman scattering (SERS) activity with an order of magnitude larger enhancement factors (EF) than the PVP-protected silver nanospheres films and the PVP-protected silver hybrid shapes films, which is confirmed by our numerical simulations. The EF of 4-MBA on the PVP-Ag NCs film are up to ~5.38 × 10⁶, and the detection limit is at least down to ~10^?8 M. The uniformity and reproducibility of the SERS signals on PVP-Ag NCs film are tested by point-to-point and batch-to-batch measurements. Meanwhile, the PVP-Ag films are also shown to be an excellent SERS substrate with good biocompatibility for hemoglobin detection. It is shown that the PVP-Ag NCs films can be used as excellent SERS substrate with good activity, uniformity, reproducibility, and biocompatibility and are promising for a myriad of chemical and biochemical sensing applications.     

Radiative lifetimes of some energy levels of doubly ionized Xenon

Using 1–5 MeV Xenon ions we have studied the beam-foil spectrum of Xenon between 105 nm and 500 nm. Radiative lifetimes were measured for levels of Xenon III. For those lifetimes which have been measured previously (Andersen et al. [l]) good agreement is obtained. The interpretation of the decay curves and the assignment of a measured value, were done with the help of theoretical lifetimes obtained by Coulomb-approximation calculations [2].     

Synthesis of fluorescent carbon dots from one-step pyrolysis of frontal-polymerized poly(acrylamide-co-4-vinylpyridine)

We report herein the synthesis of carbon dots (CDs) by a one-step pyrolysis from poly(acrylamide-co-4-vinylpyridine) [poly(AAM-co-4-VP)]. The poly(AAM-co-4-VP) was fabricated using frontal polymerization within 5 min in an easy and rapid way and then was pyrolyzed to afford CDs. The as-prepared CDs show crystalline structure and excellent dispersibility with particle sizes in the range of 2–4 nm. The optical properties were throughly investigated, and we found the CDs exhibit strong blue fluorescence with quantum yield of ~18 % and excellent photoluminescent stability, which is rarely influenced by the external conditions. This process can be exploited as an effective path for synthesis CDs with polymers by a facile and rapid way.     

Plasma-assisted hot filament chemical vapor deposition of AlN thin films on ZnO buffer layer: toward highly c-axis-oriented,uniform, insulative films

c-Axis-oriented aluminum nitride (AlN) thin film with improved quality was deposited on Si(111) substrate using ZnO buffer layer by plasma-assisted hot filament chemical vapor deposition. The optical and electrical properties and surface morphology as well as elemental composition of the AlN films deposited with and without ZnO buffer layer were investigated using a host of measurement techniques: X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, field emission scanning electron microscopy (FESEM), and current–voltage (I–V) characteristic measurement. The XRD and XPS results reveal that the AlN/ZnO/Si films are free of metallic Al particles. Also, cross-sectional FESEM observations suggest formation of a well-aligned, uniform, continuous, and highly (002) oriented structure for a bi-layered AlN film when Si(111) is covered with ZnO buffer. Moreover, a decrease in full width at half maximum of the E₂ (high)-mode peak in Raman spectrum indicates a better crystallinity for the AlN films formed on ZnO/Si substrate. Finally, I–V curves obtained indicate that the electrical behavior of the AlN thin films switches from conductive to insulative when film is grown on a ZnO-buffered Si substrate.     

Probing PM2.5 with terahertz wave

The goal of continuous ambient participate monitoring has been accomplished by the use of terahertz(THz)wave.The frequency-dependent spectrum and absorbance of the particulate matter(PM2.5)were measured in the range of 0–10 THz.The PM2.5 concentration was calculated according to the sampling time and air flow.With the increase of,the THz wave amplitude gradually decreased and the absorbance A of PM2.5 increased.The relationship between and A can be described mathematically through A0.5.Our results demonstrate that the terahertz wave could be a valuable tool to monitor and inspect the PM2.5 concentration.     

Double-walled core-shell structured Si@SiO2@C nanocomposite as anode for lithium-ion batteries

Double-walled core-shell structured Si@SiO₂@C nanocomposite has been prepared by calcination of silicon nanoparticles in air and subsequent carbon coating. The obtained Si@SiO₂@C nanocomposite demonstrates a reversible specific capacity of about 786 mAh g^?1 after 100 cycles at a current density of 100 mA g^?1 with a capacity fading of 0.13 % per cycle. The enhanced electrochemical performance can be due to that the double walls of carbon and SiO₂ improve the electronic conductivity and enhance the compatibility of electrode materials and electrolyte as a result of accommodating the significant volumetric change during cycles. The interlayer SiO₂ may release the mechanical strain and enhance the interfacial adhesion between carbon shell and silicon core.     

Methods of IR spectroscopy in monitoring of chemotherapy of oncological pathologies using palladium complexes

FTIR spectroscopy is used to study mammary-gland tissues of mice with a sarcoma tumor (strain 180). Spectral features that are typical of malignant tumors are revealed in the FTIR spectra in the sarcoma-tumor tissues. Tumor tissues are studied after treatment using coordination compounds based on palladium complexes with 3-amino-1-hydroxypropylidene-1,1-diphosphonic acid and zoledronic acid. A therapeutic effect is not revealed after treatment using palladium complex with 3-amino-1-hydroxypropylidene-1,1-diphosphonic acid. The suppression of tumor growth amounts to 59% when palladium complexes with zoledronic acid are used. Suppression of tumor growth is accompanied by variations in spectral characteristics. With respect to diagnostic features, the FTIR spectra of tumor tissues after treatment with the palladium complexes with zoledronic acid are similar to the FTIR spectra of tissues that are free of malignant tumors. Specific spectroscopic characteristics that make it possible to control the chemotherapy of oncological pathologies are determined.     

The secondary-electron background problem in electron excited auger electron spectroscopy

Dynamic background subtraction is used to demonstrate that the recently suggested spline-polynomial scheme for characterizing the secondary electron background neglects an important aspect of the Auger feature. As a consequence of this neglect, area measurements using the spline approximation are difficult to relate to the true Auger current.     

TheK Auger spectrum of the free magnesium atom

TheK Auger spectrum of free Mg atoms has been investigated with an electrostatic energy analyzer at an energy resolution of 0.16%. The ionization in theK shell of the Mg vapour was caused by electron impact. Absolute energies and relative intensities of the normal Auger transitionsK-LL and of the most intense satellite lines have been determined. The experimental energies and relative group intensities of the normal lines agree well with theoretical values. The total intensity of special classes of satellites are compatible with calculations of the shake theory within the sudden approximation.