Explicit geometry dependence of MOS transistor parameters by the pseudoboundary method

The pseudoboundary method is an engineering technique to extend the use of a single parameter set over the entire geometric design space for VLSI circuits. The technique eliminates adverse effects, such as negative output conductance, by clamping the evaluation of geometric dependence terms at the systematically determined boundaries of a primary region. The use of this technique is essential for accurate simulation of analog and digital circuits as well as prediction of circuit performance using next-generation submicron VLSI fabrication technologies. Results demonstrating the effectiveness of the technique using the widely accepted Berkeley short-channel IGFET model (BSIM) are presented, with data from transistors of different geometries ranging from 0.5 to 70 m.     

Effect of Heat Processing on the Texture Profile of Canned and Retort Pouch Packed Oil Sardine (Sardinella longiceps) in Oil Medium

ABSTRACT: Sardine in oil was canned at 3 different Lethality values (F₀ 5,7, and 9) in retort pouches and aluminum cans in stationary retort. Process time calculations were done mathematically to find out the actual process time. Sardine in oil processed in retort pouches had a lower process time compared with aluminum cans for each F₀ value. Instrumental texture analysis was done using a food texture analyzer to study the effect of thermal processing on the texture of thermally processed sardine in oil in aluminum cans and retort pouches. As the F₀ value and cook value increased in both the retort pouches and aluminum cans, the textural properties showed a decreasing trend. Hardness of the product canned in both aluminum cans and retort pouches decreased with increase in F₀ values.     

Near‐Infrared and Upconversion Luminescence in Er:Y2O3 Ceramics under 1.5 μm Excitation

Results of the spectroscopic characteristics and upconversion luminescence in Er³⁺ doped yttria (Y₂O₃) transparent ceramics prepared by a modified two‐step sintering method are presented. The near‐infrared (1.5 μm) luminescence properties were evaluated as a function of Er³⁺ concentration. Judd–Ofelt intensity parameters, radiative rates, branching ratios, and emission lifetimes were determined and compared with results reported for Er³⁺‐doped Y₂O₃ single crystal and nanocrystals. Following pumping at 1.532 μm, weak blue (~0.41 μm, ²H_9/2 → ⁴I_15/2), strong green (~0.56 μm, ²H_11/2, ⁴S_3/2 → ⁴I_15/2), and red (~0.67 μm, ⁴F_9/2 → ⁴I_15/2) emission bands were observed as well as weak near‐infrared emissions at 0.8 μm (⁴I_9/2 → ⁴I_15/2) and 0.85 μm (⁴S_3/2 → ⁴I_13/2) at room temperature. The upconversion luminescence properties under ~1.5 μm pumping were further investigated through pump power dependence and decay time studies. Sequential two‐photon absorption leads to the ⁴I_9/2 upconversion emission, whereas energy‐transfer upconversion is responsible for the emission from the higher excited states ²H_9/2, ²H_11/2, ⁴S_3/2, and ⁴F_9/2. The enhanced red emission with increasing Er³⁺ concentration most likely occurred via the cross‐relaxation process between (⁴F_7/2 → ⁴F_9/2) and (⁴I_11/2 → ⁴F_9/2) transitions, which increased the population of the ⁴F_9/2 level.     

Analysis on the saturation of refractive index modulation in fiber Bragg gratings (FBGs) written by partially coherent UV beams

We present an analysis on the saturation of refractive index modulation of fiber Bragg gratings written in nonhydrogenated Ge-B co-doped single-mode photosensitive optical fiber by partially coherent pulsed UV beams. The UV beams of different spatial coherence properties were generated by second harmonic conversion of high repetition rate, high average power copper vapor laser (CVL) oscillators with different optical resonators. It is observed that for UV beams of higher spatial coherence, the fiber Bragg grating reflectivity growth was faster and saturation of refractive index modulation was higher. The experimental results are explained with the help of a physical model based on exponential decay of defect centers per unit volume on UV absorption in the fiber core. The subsequent increase in the refractive index was attributed to the structural modification and densification of the fiber core.