MAGNETOACTIVE P-GE ROD WAVEGUIDE LOSS ANALYSIS ON THE CONCENTRATION OF TWO COMPONENT HOLE CHARGE CARRIERS / CILINDRINIŲ GIROELEKTRINIŲ P-GE BANGOLAIDŽIŲ NUOSTOLIŲ PRIKLAUSOMYBĖS NUO DVIEJŲ RŪŠIŲ KRŪVININKŲ KONCENTRACIJOS TYRIMAS

A new algorithm is utilized to examine the phase and attenuation constants of open dissipative epsilon- and (or) mu-gyrotropic rod waveguides. Our algorithm allows analyzing the waveguides made of materials having very high losses. The dispersion characteristics of p-Ge with a waveguide of two component hole charge carriers are calculated when the ratio of heavy hole concentration in the material is equal to 5%, 50% and 95% of the total free carrier concentration. The effective mass of p-Ge heavy and light holes are 0.279me and 0.043me respectively. The dispersion characteristics of the main and eight higher modes are presented in the paper. The transformation of higher hybrid modes at some heavy hole concentrations can be noticed. Waveguide broad bandwidth can be considerably extended due to the fact that the losses of higher modes are larger in comparison to those of the main mode at certain heavy hole concentration. Santrauka Darbe pateikiami dviejų rūšių krūvininkų (lengvųjų ir sunkiųjų skylučių) puslaidininkinių p-Ge giroelektrinių bangolaidžių, kuriuos veikia B 1 0 = r T indukcijos nuolatinis išilginis magnetinis laukas, dispersinių charakteristikų skaičiavimo rezultatai, įvertinant nuostolius bangolaidyje. Skaičiavimo algoritmas leidžia tirti bangolaidžius, pagamintus iš medžiagų, atnešančių labai didelius nuostolius. Tiriamos 1 mm spindulio bangolaidžių dažninės charakteristikos 5–200 GHz dažnių ruože. Laisvųjų krūvininkų koncentracija bangolaidyje yra N = 5·1019 m–3. Nustatoma nuostolių priklausomybė nuo sunkiųjų skylučių krūvininkų koncentracijos Nh, esant trims skirtingoms sunkiųjų skylučių koncentracijoms, kai Nh sudaro 5 %, 50 % ir 95 % nuo visų krūvininkų koncentracijos N bangolaidyje. Reikšminiai žodžiai: girotropiniai, giroelektriniai bangolaidžiai, p-Ge, puslaidininkių plazma, nuolatinis magnetinis laukas, dielektrinės skvarbos tenzorius, sunkiosios ir lengvosios skylutės, nuostoliai, dispersinės charakteristikos, kompleksinė išilginė sklidimo konstanta

Development of efficient designs of cooking systems. III. Kinetics of cooking and quality of cooked food, including nutrients, anti-nutrients, taste, and flavor

Part III of the series on cooking systems presents a qualitative description of cooking methods such as open pan cooking, pressure cooking, steam cooking, solar energy-based cooking, microwave cooking, etc. A large number of chemical and physical changes occur during the process of cooking. These changes have been comprehensively covered in published literature including some textbooks. An attempt has been made to discuss a brief coherent description regarding the changes occurring in starches, proteins, fats, etc. The kinetics of the cooking reaction has also been investigated. This information can be advantageously employed for developing a protocol for an optimum temperature-time program. Because the cooking process is practically thermally neutral, a good scope is available for the optimization of energy supply. It was also thought desirable to understand the kinetics of degradation of proteins, vitamins, anti-nutrients, and flavors in different cooking practices, including microwave ovens and pressure cookers. The mechanism of cooking of rice and lentils has been described. The cooking process involves first the transfer of water from bulk to the particle surface, where the resistance for transfer is provided by a thin film in the vicinity of grain (rice and lentils) surfaces. Second, water has to transfer from the external surface to swollen cooked mass to uncooked core. Finally, on the surface of the uncooked core, the cooking reaction occurs. All published literature regarding this mechanism has been systematically analyzed, and the procedure has been given regarding the rate controlling step(s) and the estimation of the overall rate of cooking. For this purpose, the mathematical models have been given and methods have been described for the quantitative evaluation of the model parameters. A substantial amount of additional work is needed on the mechanism of cooking and suggestions have been made for future research. © 2011 American Chemical Society

Vertically Aligned Silicon Nanowire Array Decorated by Ag or Au Nanoparticles as SERS Substrate for Bio-molecular Detection

This review article summerises preparation techniques of vertically aligned silicon nanowire (Si NW) arrays through metal-assisted chemical etching (MacEtch) process and plasmonic nanoparticles (Ag and Au) with the perspective of the fabrication of surface-enhanced Raman scattering (SERS)-active substrates which are highly efficient for bio-molecular detection. At first, basic methods and mechanisms for SERS have been introduced and size and shape effects of the nanoparticles (NPs) on plasmonic vibration have been discussed. Comparative discussions on optical and plasmonic characteristics of Ag and Au NPs have also been presented in this section. Potential techniques for the synthesis of Ag and Au NPs with different sizes and shapes have been reported in the following section. Basic processes and mechanism for the fabrication of vertically aligned Si NW arrays on Si by MacEtch of Si wafer have been discussed. Template-assisted fabrication techniques for the vertically aligned Si NW arrays with controlled diameter and number density have also been reported. Finally, multifarious ways for the fabrication of SERS-active substrates by assembling noble metal NPs onto the NW surface have been discussed and their performance for bio-molecular detection has also been reported