Low-Loss Slow Light Transmission in Photonic Crystal Waveguides Comprising of Liquid Crystal Infiltration

A low loss photonic crystal(PhC) waveguide having rectangular air holes in Si core is proposed having an average group index of 55 in the bandwidth of 1.2 THz.The possible propagation losses due to inefficient coupling are also investigated for proposed structure.It is found that high transmission is obtained for a broad bandwidth from the output of the finally designed heterogeneous waveguide consisting of a slow liquid crystal infiltrated PhC waveguide surrounded by fast PhC waveguides on both sides.     

Numerical analysis of crack initiation and growth in cylindrical geometries with an axial flaw

In this work we study the initiation and growth of a semi-elliptical internal axial crack in the wall of an internally pressurised cylinder. We show that small diameter structures, which we may call ‘tubes’, are more likely to undergo noticable yield before a small internal flaw starts to grow. However, when growth starts, it is likely to be catastrophic. On the other hand, large diameter structures, called ‘pipes’, can fail by cracking at reasonable design pressures. We have also shown that a small semi-elliptical crack attains a particular (almost circular) shape during growth irrespective of its initial aspect ratio.     

Part I: Mixed-Signal Performance of Various High-Voltage Drain-Extended MOS Devices

In this paper, the optimization issues of various drain-extended devices are discussed for input/output applications. The mixed-signal performance, impact of process variations, and gate oxide reliability of these devices are compared. Lightly doped drain MOS (LDDMOS) was found to have a moderate performance advantage as compared to shallow trench isolation (STI) and non-STI drain-extended MOS (DeMOS) devices. Non-STI DeMOS devices have improved circuit performance but suffer from the worst gate oxide reliability. Incorporating an STI region underneath the gate–drain overlap improves the gate oxide reliability, although it degrades the mixed-signal characteristics of the device. The single-halo nature of DeMOS devices has been shown to be effective in suppressing the short-channel effects.      

Defected Ground Based Fractal Antenna for S and C Band Applications

Wireless Personal Communications - Defected ground based modified rectangular fractal patch antenna for mobile devices communication in Delay Tolerant Networks, Wireless sensor networks and Mobile...     

Photoconductivity, photovoltaic effect and photoluminescence in chemically deposited films of (Cd0.95–Pb0.05)S:CdCl2,Gd

Results of XRD, optical absorption spectra, photoconductivity, photovoltaic effect and photoluminescence are reported for (Cd_0.95–Pb_0.05)S:CdCl₂,Gd films prepared by chemical deposition technique at 60 °C and room temperature (RT). The XRD studies show prominent diffraction lines of CdS and PbS. Optical absorption spectra show direct bandgap nature with decreasing value due to addition of PbS. The saturated photocurrent (I_pc) to dark current (I_dc) ratios 10⁷ are found in films prepared at 60 °C and 10⁴ in films prepared at RT. Photoluminescence is found to be brighter in films prepared at RT. Photovoltaic efficiency 5% has been observed in such films.     

Counterfeit capacitors in the supply chain

Counterfeit electronic components have become a significant concern in the electronic parts supply chain. Original equipment manufacturers in particular are concerned about counterfeit components as there have been several recent reports of counterfeit parts entering the supply chain of the US military. This paper presents a case study of multilayer ceramic capacitors for use in a printed circuit assembly in an electronic system on a military aircraft. The capacitors failed during a high temperature screening test. Upon failure analysis it was revealed that the capacitors were not made to the correct specifications and were suspected to be counterfeit and not the authentic military grade capacitors manufactured by Kemet. Further investigation revealed that the suspect multilayered ceramic capacitors had entered into the electronics parts supply chain and were sold as authentic Kemet capacitors that met the higher military-specified requirements. The manufacturing and distribution of the counterfeit capacitors were traced to locations where, according to Kemet, its authentic capacitors are neither manufactured nor distributed.     

Stone fragmentation by ultrasound

The presence of kidney stone in the kidney causes discomfort to patients. Hence, removal of such stones is important which is commonly done these days, non-destructively, with lithotripters without surgery. Commercially, lithotripters like extra-corporeal shock wave lithotripters (ESWL) made by Siemens etc are in routine use. These methods are very cumbersome and expensive. Treatment of the patients also takes comparatively more time because of more number of sittings. Some delicate nerves and fibres in the surrounding areas of the stones present in the kidney are also damaged by high ultrasonic intensity used in such systems. In the present work, enhancement of the kidney stone fragmentation by using ultrasound is studied. The cavitation bubbles are found to implode faster, with more disintegration efficiency of the lithotripters, which give better treatment to the patients.     

Mechanism of persulfate decomposition in aqueous solution at 50°C in the presence of vinyl acetate and nitrogen

The rate of the thermal decomposition of potassium persulfate has been studied in an unbuffered aqueous solution at 50°C in nitrogen atmosphere in the presence of vinyl acetate (VA) monomer (M). It has been found that the initial rate of persulfate decomposition may be written as in the concentration range of persulfate (1.85 × 10^?2–1.85 × 10^?3 m/dm³) and VA (0.054–0.27 m/dm³). The pH of the aqueous solution of persulfate was found to decrease continuously at 50°C, but there was no measurable change of pH of the aqueous solution containing persulfate and VA at 50°C in the presence of nitrogen at the early stages of the reaction. VA, methyl acetate, and ethyl acetate have been found to undergo very slow hydrolysis in aqueous solution at 50°C. The partition coefficient (β) of the monomer between the polymer phase and the aqueous phase was found to be 21 ± 2 in the presence and absence of electrolytes (K₂SO₄, 10^?4–10^?3 m/dm³) by the bromometric estimation of the monomer present in the aqueous phase containing known amounts of monomer [1.80–2.20%, w/v] and freshly prepared polymer (0.3–0.5 g/100 mL). Above 10^?2 (m/dm³) persulfate, the polymer obtained was found to be insoluble in common solvents, viz., acetone, benzene, etc. Highly purified sodium dodecyl sulfate (0.5–5.0 × 10^?3 m/dm³) had no measurable effect on the rate of persulfate decomposition.     

Studies on microstructure of silicon thin films and its effect on solar cells

Intrinsic microcrystalline silicon films have been deposited at high-power–high-pressure regime. Effects of pressure and hydrogen dilution on the microstructures of the films have been investigated. Crystalline size decreases at high pressure although the deposition rate increases up to 10 Å/s. Microstructure depends sensitively on pressure as well as on hydrogen dilution of silane. Single junction solar cells have been fabricated with Si films having different degrees of crystallinity and grain size and the performances have been studied.