Mass Spectrometric Studies of Positive Ion/Molecule Reactions in NH3 and SF6 Gases

Positive ion-molecule reactions in NH] and SF6 gas were studied in a static ion drift-tube mass spectrometer. E/N (the ratio of electric field strength to gas number density) varied typically from 20-400 Td and pressure ranged from 0.1 to 0.8 Torr. The most important process was found to b

Pengesan Optik, Piezoelektrik-fotoakustik

An optical detector based on piezoelectric detection of the photo acoustic effect in an absorbing metal plate is reported. Such a detector has been used in an experiment for measuring a Gaussian laser beam diameter using the knife-edge method. The responsivity of the detector varied from 4.05J.LV/mW at 68Hz to 1.25J.LV/mW at 211Hz. The Gaussian laser beam diameter obtained from the experimental data is (0.88 ± 0.02)mm and this value is comparable with the value stated in the laser specification note

Does Syariah-Compliant stocks overreact?

This is a preliminary study on stock overreaction behavior of syariah compliant stock in Bursa Malaysia over the period between January 1988 and December 2009. Results show that syariah compliant stock in Bursa Malaysia, like their conventional counterparts overreact. The overreactions are more pronounced during the sub-period prior to 1997 Asian Financial Crisis and Global 2008 Crisis. After the crisis the overreaction behavior seems to diminish

Effect of high intensity light irradiance on CuInSe2 thin films

CuInSe2 has been a good candidate for photovoltaic material due to its direct band gap and high absorption coefficient. As the stability of photovoltaic are generally dependent on the aggressive environment, i.e. sun light, the CuInSe2 thin film can degrade after long exposure of high intensity light irradiance. The present study reports on the effect of high intensity light irradiance to the electrical and optical properties of thermal evaporated CuInSe2 thin films. The thin films were exposed to light intensity of 250 W/m2, 500 W/m2, 750 W/m2, 1000 W/m2 and 1500 W/m2 using halogen lamp. We noticed an increasing trend in resistivity after light exposure at all intensities due to the increase of light-induced defects in the films which act as recombination centre for electron-hole pair. Crystallinity of CuInSe2 thin films decreases with increasing intensity of light exposure as a result of light-induce defect. CuInSe2 thin films are found to have higher optical band gap compared to reported 1.01eV due to the amorphous structure of the film and relatively higher surface roughness

Influence of metallic molar ratio on the electron spin resonance and thermal diffusivity of Zn-Al layered double hydroxide

The coprecipitation method was used to prepare Zn-Al layered double hydroxide (Zn-Al-NO3-LDH) at pH 7.5 and different Zn 2+/Al3+ molar ratios of 2, 3, 4, 5, and 6. The elemental, structural, and textural properties of prepared samples were studied. The crystallinity of prepared LDH nanostructure decreases as Zn2+/Al 3+ molar ratio increases. The electron spin resonance (ESR) spectroscopy of different LDH samples showed new ESR spectra. These spectra were produced due to the presence of different phases with formed LDH such as ZnO phase and ZnAl2O4 spinel. At low Zn2+/Al 3+ molar ratio, the ESR signals were produced from the presence of free nitrate anions in the LDH interlayer. Above Zn2+/Al3+ = 2, the ESR signals were attributed to the existence of ZnO phase and ZnAl2O4 spinel in the samples. Because the nuclear magnetic moment of 67Zn is lower than 27Al, the increasing in Zn2+/Al3+ molar ratio causes a reduction of the magnetic activity of ZnAl2O4 spinel. Thermal diffusivity versus in situ temperature showed nonlinear relation for different samples due to the changing in the water content of LDH as temperature increases. The dc conductivity of samples decreased as Zn2+/Al3+ molar ratio

Studies of monomer impregnation and polymerised in situ in wood using dynamic mechanical thermal analyser.

Ten tropical hardwoods are impregnated with methyl methacrylate and polymerised in‐situ by use of catalysts and heat techniques. Treatability of the wood, as determined from the fractional volumetric retentions of monomers that are a fraction of voids filled by the impregnant, showed that the mean retention range from 15·03% (Acacia Mangium) to 56·59% (Cratoxylum Arborescens). The penetration of the monomer evaluated using ultrasonic waves showed that the treated wood had higher velocities which indicated significant increase in density. The present paper deals with the viscoelastic relaxation of polymerised treated wood. The efficiency of the monomer as a plasticiser is studied through the temperature dependence of the storage modulus (E′) and loss tangent (tan δ) of treated and untreated wood by dynamic mechanical thermal analysis (DMTA) over a temperature in the range from −100 to 200°C. The storage modulus E′ decreased with temperature and as the maximum mechanical damping developed, the glass transition temperature (T g) of the plasticised wood decreased with the plasticiser content

Analysis of Pb(II) ion sensing by crosslinked chitosan thin film using surface plasmon resonance spectroscopy

The crosslinked chitosan thin film had been studied as a sensor element of surface plasmon resonance (SPR) optical sensor. Crosslinked chitosan solution was synthesized by homogeneous reaction of medium molecular weight chitosan in aqueous acetic acid solution with glutaraldehyde as crosslinking agent. It was deposited on gold film by spin coating. Using SPR technique, the optical properties of crosslinked chitosan thin film before and after contacting with different concentration of Pb(II) ion in a range of 0.5–100 ppm had been obtained by fitting. The resonance angle shifted to lower value as the Pb(II) ion concentration increased. Changes in the resonance angle (Δθ) are directly proportional to the concentration of Pb(II) ion solution. X-ray photoelectron spectroscopy (XPS) had been employed to confirm chemical elements and their bonding of the thin film prior to adsorption, as well as chemical interactions involved between Pb(II) ion and the thin film

ESR spectra and thermal diffusivity of Zn-Al layered double hydroxide

ZnAlNO3LDH was synthesized using the co-precipitation method at pH 7±0.1 and ratio Zn/Al=4. The heat treatment of LDH was studied by X-ray diffraction (XRD) and thermogravimetric analysis (TGA/DTG) to investigate the stability of the LDH structure. The in situ electron spin resonance (ESR) spectra of fresh LDH from room temperature up to 190 °C were obtained, which are due to the presence of nitrate radicals in LDH interlayer. ESR spectra of sintered LDH below 200 °C (ex situ ESR spectra) were investigated, which are also due to the nitrate radicals. However, at 200 °C and above, spectra were due to the oxygen vacancies of ZnO, which was formed during the thermal treatment of LDH. Thermal diffusivity of LDH as a function of in situ temperatures results in a nonlinear relation, which is due to the changing water content of LDH when temperature increases. However, thermal diffusivity of LDH as a function of sintered temperatures showed a linear relation and the slope of these data demonstrated the dependency between thermal diffusivity and water content of LDH below 200 °C. For temperature above 180 °C, the thermal diffusivity behavior was mainly due to the ZnO phase in LDH