High-k Dielectric Thickness and Halo Implant on Threshold Voltage Control

High-k dielectric oxides have been used to replace the widely used silicon dioxide (SiO2) gate dielectrics to overcome physical limits of transistor scaling. The thickness of high-k gate dielectric influences the threshold voltage (VTH) and off-state leakage current (IOFF). A device with high drive current (ION) and low IOFF gives a high on-off current ratio (ION/IOFF), which leads to a faster switching speed for the Ntype Metal Oxide Semiconductor Field Effect Transistor (NMOS). In order to achieve the best ION/IOFF ratio for a predetermined range of VTH, halo implant was used to adjust the threshold voltage. The finding shows that optimum VTH and ION/IOFF ratio can be achieved by selecting the most suitable halo implant dose in a virtually fabricated 14nm gate-length La2O3-based NMOS device with varying high-k dielectric oxide thickness

Multi-wavelength fiber laser with erbium doped zirconia fiber and semiconductor optical amplifier

Multi-wavelength hybrid fiber lasers are demonstrated in both ring and linear cavities using a fabricated Erbium-doped Zirconia fiber (EDZF) and semiconductor optical amplifier (SOA) as gain media. In both configurations, the a fiber loop mirror, which is constructed using a 3 m long polarization maintaining fiber (PMF) and a polarization insensitive 3dB coupler is used as a comb filter for the fiber laser. In the ring cavity, 10 simultaneous lines with peak power above -26 dBm is obtained at 1550 nm region. This is an improvement compared to the linear cavity configuration which has only 5 simultaneous lines observed from wavelength 1556.1 nm to 1563.0 nm with the peak power above -40 dBm. Both hybrid lasers has a constant line spacing of 1.7 nm, which is suitable for wavelength division multiplexing and sensing applications and shows a stable operation at room temperature

Isolation of Bacillus producing Chitinase from Soil: Production and Purification of Chito-oligosaccharides from Chitin Extracted from Fresh Water Crustaceans and Antimicrobial Activity of Chitinase

In the present investigation Bacillus sp. strain was isolated and screened from the red soil collected from Doiwala region of Dehradun (U.K), India. Serial dilution technique was adopted to isolate the organism and was screened for its chitinolytic activity. The biochemical tests were performed to prove its validity. The microorganism was also screened by inoculating a loop full of the isolated strain in basic cresol red dye and incubated for about 18- 24 h. The conversion of colour of the red dye into purple (pH, 6.5- 8.8) was taken as an indication for the presence of Bacillus sp. Amylase production by the organism was also screened by introduction of iodine in the broth/agar culture having starch. The broth/agar medium having starch but no bacterial strain was used as the control. The disappearance of color confirmed the presence of Bacillus strain producing amylase which degrades the starch. The chitinous wastes were collected from fresh water crustaceans viz. fresh water crab (Potamon sp.) and fresh water prawn (Palaemon sp.) and the chitin extracted was used as the substrate for chitinase. The yield of chitin extracted from fresh water prawn (Palaemon sp.) was found to be comparatively higher than that of chitin extracted from fresh water crab (Potamon sp.). Standard colloidal chitin was used as the reference control. The enzyme activity of chitinase for degradation of chitin extracted from crab and prawn was compared. The results confirmed that chitinase activity for degradation of crab chitin was comparatively higher than that of degradation of prawn chitin. The enzyme activities were found to be 0.11 µg/ml/minute and 0.09 µg/ml/minute for degradation of crab and prawn chitin respectively. The antimicrobial activity of chitinase extracted was determined against the bacterial and fungal cultures. Potent antibacterial activity of chitinase was observed against the bacterial cultures but no antifungal activity was observed. The chitinase produced by the species was able to degrade the chitin and chito-oligosaccharides produced was separated by TLC and purified by HPLC

Predicting the Likely Thermal Impact of Current and Future Dams Around the World

Selective water release from the deeper pools of reservoirs alters the temperature of downstream rivers. Thermal destabilization of downstream rivers can be detrimental to the riverine ecosystem by disturbing the growth stages of various aquatic species. To predict this impact of planned hydropower dams worldwide, we present a framework called “FUture Temperatures Using River hISTory (FUTURIST).” The framework used historical records of in-situ river temperatures for existing dams in the U.S. and remote sensing observations for those in other regions to train an artificial neural network (ANN) model that predicts temperature change between upstream and downstream rivers. Validation of FUTURIST-modeled impacts for dams worldwide showed promising results with a root mean squared error of 2.5°C (0.9°C) and categorical accuracy of 63% (88%) during the summer (winter) season. The trained ANN model afforded prediction of the likely thermal impacts of 216 planned dams. Results suggest that during the summer season, 73% of future dams will potentially cool downstream rivers by up to 6.6°C. Winter season operations were predicted to consistently warm downstream rivers by temperatures of up to 2°C. Reservoirs that experience strong stratification have the most potential to impact downstream pre-dam thermal regimes. For copious existing or planned dams worldwide that are yet to be mapped of their thermal impacts, FUTURIST provides an efficient path forward to carry out a global thermal assessment and design sustainable hydropower expansion plans so that the upcoming dams can be operated in a more eco-sensitive manner than the existing ones