Thermal, Optical, and Electrical Properties of Gel Grown ZMTC

The bimetallic thiocyanate of the group IIB divalent d¹⁰ ions Zn²⁺ and Hg²⁺ having unique characteristics: The pale color and high thermal stability—Zinc Mercury tetrathiocyanate (ZMTC) is chosen for growth and study. ZMTC is grown in silica gel by chemical reaction method and characterized by single crystal XRD, FTIR, FT-Raman, UV-Vis-NIR, NLO, TGA/DTG, DSC, AC conductivity, and dielectric studies. It has wide transparency window and possesses high second harmonic generation efficiency. Its thermal stability is very high. The dielectric permittivity of this material is very low.     

Unidirectional growth,structural, optical and mechanical properties of LTA crystal

Nonlinear optical amino acid single crystal of l-tartaric acid was successfully grown by unidirectional Sankaranarayanan–Ramasamy method under ambient conditions for the first time. The grown single crystal was subjected to different characterization analyses in order to find out its suitability for device fabrication. The crystal system and lattice parameters were determined from the powder X-ray diffraction analysis. The crystalline perfection was evaluated using high-resolution X-ray diffractometry. It is evident from the optical absorption study that crystal has excellent transmission in the entire visible region with its lower cut off wavelength around 220 nm. The mechanical properties of the grown crystals were studied using Vickers microhardness tester.     

Spectroscopic, thermal and mechanical behavior of allylthiourea cadmium chloride single crystals

Allylthiourea cadmium chloride, a promising non-linear optical material was grown from aqueous solution by slow evaporation technique. Single crystal X-ray diffraction studies reveal that the crystal is trigonal structure with R3C space group. The spectroscopic properties were investigated by recording the Fourier transform infrared and optical absorption spectra. The dielectric studies of the sample were carried out at varying temperatures in the frequency range from 50 Hz to 5 MHz. The thermal properties were studied using thermogravimetric analyses and photopyroelectric technique. It is evident from the thermal studies that the decomposition of the crystal begins around 200 °C. The microhardness test conducted on the grown crystal suggests that the crystal has a relatively high mechanical strength. The second harmonic generation efficiency of the crystal was studied and found to be nearly 1.5 times that of urea.     

Sleepy keeper style based Low Power VLSI Architecture of a Viterbi Decoder applying for the Wireless LAN Operation sustainability

Analog Integrated Circuits and Signal Processing - Remarkable progress in the field of wireless communication has created a research interest for Viterbi decoder with long duration of battery life,...     

Investigation on one-pot hydrothermal synthesis,structural and optical properties of ZnS quantum dots

The advantage of hydrothermal synthesis of semiconductor quantum dots (QDs) over the control of particles size, morphology and stability is reported here. In a typical synthesis procedure, the zinc and sulfur precursor molar ratio of 1:3 was used in an aqueous solution at 150 °C. The cubic phase of ZnS with average particles size of 5 nm was confirmed and estimated from the X-ray diffraction (XRD) analysis. The composition and purity of the sample were analyzed from (energy dispersive-ray analysis) EDAX and (X-ray photoelectron spectroscopy analysis) XPS spectra. The absorption spectrum shows the large shift in the absorption band over 90 nm due to the quantum confinement of carriers. The emission spectrum of quantum dots carry more evidence on the presence of shallow trap, deep trap in the band gap of the material responsible for weak emission in the spectral region of 450–500 nm. High resolution transmission electron microscope and scanning electron microscope studies reveal the structural and morphological features of ZnS with slightly distorted spherical morphology. We found that the coordinating ability of solvent strongly influences the reaction process and morphology of the products.     

Optimization of the process parameters for the removal of boron from drinking water by electrocoagulation—a clean technology

BACKGROUND: There are a number of articles related to removal of boron by electrocoagulation using aluminium electrodes, but there are fewer articles describing the use of magnesium as the anode material. The main disadvantage of aluminium electrodes is the residual aluminium present in the treated water due to cathodic dissolution, which can create health problems. In the case of magnesium electrodes, there is no such disadvantage. This paper presents the results of studies on the removal of boron using magnesium and stainless steel as anode and cathode, respectively. RESULTS: Results show that a maximum removal efficiency of 86.32% was achieved at a current density of 0.2 A dm^?2 and pH of 7 using magnesium as the anode and stainless steel as the cathode. The adsorption of boron fitted the Langmuir adsorption isotherm, suggesting monolayer coverage of adsorbed molecules. The adsorption process follows second‐order kinetics. Temperature studies showed that adsorption was endothermic and spontaneous in nature. CONCLUSIONS: The magnesium hydroxide generated in the cell remove the boron present in the water and reduced to a permissible level and making it drinkable. The process scale up results was consistent with the results obtained from the laboratory scale, showing the robustness of the process. Copyright © 2010 Society of Chemical Industry     

Investigations on the nucleation kinetics of Tetrathiourea mercury(II) tetrathiocyanato zinc(II) single crystals

The solubility and metastable zone width of Tetrathiourea mercury(II) tetrathiocyanato Zinc(II): Hg(N₂H₄CS)₄Zn(SCN)₄ (TMTZ) were determined for the first time and thereby the possibility of growing bulk size single crystals of TMTZ in a mixture solvent of ethanol and water was estimated. The induction period was recorded for the different supersaturation ratios (S = 1.1, 1.2, 1.3 and 1.4), which reveals that the induction period of TMTZ decreases with increase in supersaturation. The metastable zone width of TMTZ was found to be in the range 35-45 °C. The measured value of interfacial tension values found to vary from 0.9318 to 2.048 mJ/m².     

Synthesis and characterization of one dimensional semiconducting nanorods and nanobelts

CdSe nanorods, nanobelts are synthesized via a simple sacrificial template assisted solvothermal route at a moderate temperature of 180°C. The influences of introducing sacrificial template, hydrazine hydrate (N₂H₄·H₂O) as the reducing agent, ammonia (NH₃·H₂O) and NaOH as the complexing agent on the morphology and size of the obtained CdSe nanorods and nanobelts are investigated and reported. CdSe nanorods with a mean diameter and length of 25 nm and 82 nm respectively are synthesized and the problem of handling the stacking faults present in the long CdSe is analyzed. The structural phase, morphology and the optical properties of CdSe nanorods and nanobelts are studied using powder X-ray diffraction, TEM/HRTEM, UV-visible absorption spectroscopy and photoluminescence (PL) spectroscopy respectively.     

Influence of Metallic Substitutions on the Optical and Mechanical Properties of NLO Benzoyl Glycine Crystals

Benzoyl glycine （BG） is a promising organic nonlinear optical （NLO） crystal, whose second harmonic generation （SHG） efficiency is much higher than that of KDP （potassium dihydrogen phosphate）. Single crystals of pure, Cu2＋ and Cd2＋ doped BG were grown by slow evaporation technique. Optically transparent and defect free single crystals of size up to 10 mm×15 mm×10 mm were harvested in a period of 40-60 days. The growth conditions of pure and doped crystals of BG were optimized and the grown crystals were confirmed by single crystal XRD （X-ray diffraction）. The grown crystals were characterized by FTIR （Fourier transform infrared spectroscopy）, optical absorption and microhardness studies. The microhardness studies confirm that BG has a moderate VHN （Vickers hardness number） value in comparison to the.other organic NLO crystals. The efficiency of frequency doubling was measured for the using Nd：YAG laser and the results were discussed.     

Crystal structure,optical and thermal studies of a new organic nonlinear optical material: l-Histidinium maleate 1.5-hydrate

A new organic nonlinear optical material l-histidinium maleate 1.5-hydrate (LHM) with the molecular formula C₁₀H₁₆N₃O_7.5 has been successfully synthesized from aqueous solution by slow solvent evaporation method. The structural characterization of the grown crystal was carried out by single crystal X-ray diffraction at 293(2) K. In the crystal, molecules are linked through inter and intramolecular NH?O and OH?O hydrogen bonds, generate edge fused ring motif. The hydrogen bonded motifs are linked to each other to form a three dimensional network. The FT-IR spectroscopy was used to identify the functional groups of the synthesized compound. The optical behavior of the grown crystal was examined by UV–visible spectral analysis, which shows that the optical absorption is almost negligible in the wavelength range 280–1300 nm. The nonlinear optical property was confirmed by the powder technique of Kurtz and Perry. The thermal behavior of the grown crystal was analyzed by thermogravimetric analysis.