The effect of external electric field on mass attenuation coefficients of some semiconductor

In this study, we measured the mass attenuation coefficient of n-type GaAs, p-type GaAs, n-type Si and Au/n-Si/n⁺Si/Al samples with and without external electric field. Samples were set in perpendicular direction to the 100?mCi ²⁴¹Am radioactive source and counts were made with a NaI(Tl) detector. It was observed that when an external electric field was applied onto the samples, mass attenuation coefficients were increased. Results showed that this study is consistent with previous studies.     

Photon attenuation coefficients of different rock samples using MCNPX,Geant4 simulation codes and experimental results: a comparison study

ABSTRACT

The photon attenuation coefficients for the rocks (Feldspathic basalt, Compact basalt, Volcanic rock, Pink granite, Sandstone and Dolerite) have been investigated using MCNPX and Geant4 codes for photon energies 122, 356, 511, 662, 1170, 1275 and 1330 keV. Comparison of the simulation and experimental results of mass attenuation coefficients is presented. The exposure buildup factors also have been calculated with the help of the G-P fitting method. The comparison showed reasonable agreement between the simulated and experimental data for all rocks. The results show that sandstone has the highest mean free path as well as exposure buildup factor which signifies that sandstone requires a larger thickness for protection from photons.     

Dipyrazinium Tri(fluorotrioxochromate): An Efficient Oxidant for Organic Substrates

Summary. The first polymeric halotrioxochromate, dipyrazinium tri(fluorotrioxochromate), was prepared and used for quantitative oxidation of several organic substrates. This novel compound is more efficient than, and has certain advantages over, its monomeric analogues in terms of the amount of oxidant required, reaction times, and yields.     

Measurement of L shell X-ray fluorescence intensity ratios for some elements in the atomic number range of 66£Z£90 by photoionization of consecutive L-subshells

In 1999 investigation, the needles of Sabina chinesis L. from 11 hot spot tourist cities extending over China were collected as biomonitors for evaluation of atmospheric elemental differences in those cities. Thirty five elements were determined by instrumental neutron activation analysis (INAA). The experimental data reflected the environmental alteration in the cities that have different geographical position, population burden and industrialized level. Eventually by using the data processed by factor analysis (FA) and subsequent cluster analysis (CA), the cities were grouped into six sorts of the urban atmospheric deposition with corresponding elements.     

Electrochemical biosensor based on self-assembled monolayers modified with gold nanoparticles for detection of HER-3

We have developed a new immunological biosensor for ultrasensitive quantification of human epidermal growth factor receptor-3(HER-3). In order to construct the biosensor, the gold electrode surface was layered with, hexanedithiol, gold nanoparticles, and cysteamine, respectively. Anti-HER-3 antibody was covalently attached to cysteamine by glutaraldehyde and used as a bioreceptor in a biosensor system for the first time by this study. Surface characterization was obtained by means of electrochemical impedance spectroscopy and voltammetry. The proposed biosensor showed a good analytical performance for the detection of HER-3 ranging from 0.2 to 1.4 pg mL⁻¹. Kramers–Kronig transform was performed on the experimental impedance data. Moreover, in an immunosensor system, the single frequency impedance technique was firstly used for characterization of interaction between HER-3 and anti-HER-3. Finally the presented biosensor was applied to artificial serum samples spiked with HER-3.     

Crystal structure of (<Emphasis Type="Italic">E</Emphasis>)-3-fluoro-N-((5-nitrothiophen-2-yl)methylene)aniline

The structure of the title compound C₁₁H₇FN₂O₂S was characterized by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P2₁/n with Z = 12, i.e. with three molecules in asymmetric unit. The molecules are not planar: the dihedral angles between the planes of thiophene and the benzene rings are 42.3(3)°, 42.0(3)°, and 48.9(2)°. In the crystal, intermolecular C–H···F interactions link the molecules through R₂² (14) ring motif. The crystal packing is also stabilized by π···π interactions.     

Separation and quantification of the urinary enantiomers of 2-hydroxyglutaric acid by capillary electrophoresis with capacitively coupled contactless conductivity detection: Application to the diagnosis of D- and L-2-hydroxyglutaric aciduria

2-hydroxyglutaric aciduria is an inherited neurometabolic disorder with two major types: D-2-hydroxyglutaric aciduria and L-2-hydroxyglutaric aciduria. An easy and fast capillary electrophoresis system combined with a capacitively coupled contactless conductivity detection method was developed for the enantioseparation and determination of D- and L-2-hydroxyglutaric acid in urine. D- and L-2-hydroxyglutaric acids were separated using vancomycin as the chiral selector. The optimal separation conditions for enantiomers were achieved by the use of a buffer containing 50 mM 4-(N-morpholino) butane sulfonic acid solution (pH 6.5), an electroosmotic flow modifier (0.001% [w/v] polybrene), and 30 mM vancomycin as chiral selector. The analysis time was 6 min under optimal conditions. The optimized and validated method was successfully implemented for quantifying D- and L-2-hydroxyglutaric aciduria in patients’ urine, without any pretreatment step. The linearity of the method was determined to be in the range of 2–100 mg/L for D- and L-2-hydroxyglutaric acid in urine. The precision (relative standard deviation%) was obtained at about 7%. For D- and L-2-hydroxyglutaric acids, the limits of detection were 0.567 and 0.497 mg/L, respectively.     

Planar Dielectrochromatography in a Vertical Chamber

JPC – Journal of Planar Chromatography – Modern TLC - Drawn by capillary forces the developing solvent (mobile phase) migrates through the thin layer (stationary phase) over a defined...