Thresholds of optical limiting in solutions of nanoscale compounds of zinc phthalocyanine with galactopyranosyl radicals

The optical limiting (OL) of nanosecond laser pulses in solutions of newly synthesized dyes in dimethyl sulfoxide (DMSO) has been investigated. These dyes are compounds of zinc phthalocyanine (ZnPc) with D-galactopyranosyl radicals (Gal) located in the peripheral (p-GalZnPc) and nonperipheral (n-GalZnPc) positions with respect to the ZnPc macrocycle. Experiments have been performed using laser radiation with a wavelength of 532 nm, at which the optical absorbance of solutions of ZnPc, p-GalZnPc and n-GalZnPc dyes is four orders of magnitude lower than the absorbance in the peaks at wavelengths of 671, 680, and 701 nm, respectively. It is established that solutions of p-GalZnPc and n-GalZnPc in DMSO have a much lower OL threshold in comparison with ZnPc solution; the nonlinearity of p-GalZnPc solutions exceeds that of n-GalZnPc solutions. OL thresholds for the dyes under study in a wide concentration range are determined.     

An empirical HBT large‐signal model for CAD

A new, simple heterojunction bipolar transistor (HBT) large‐signal model for use in CAD is proposed and experimentally evaluated. The important development in this model is that the main model parameters are derived directly from the measurements taken during typical operating conditions. The model was evaluated with extensive measurements at different temperatures by DC, S, and power‐spectrum measurements. Good correspondence was obtained between the measurement and experimental results. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13, 518–533, 2003.     

Optical contrast formation in amorphous silicon carbide with high-energy focused ion beams

Thin films (d ～ 1 μm) of hydrogenated amorphous silicon carbide (a-Si_1?xC_x:H), deposited by RF reactive magnetron sputtering with different carbon content x, have been implanted with high fluences (Φ = 1016–1017 cm^?2) of high-energy (E = 0.2–1 MeV) He⁺ ions as the implant species. The induced structural modification of the implanted material results in a considerable change of its optical properties, best manifested by a significant shift of the optical absorption edge to lower photon energies as obtained from photo-thermal-deflection spectroscopy (PDS) data. This shift is accompanied by a remarkable increase of the absorption coefficient over one order of magnitude (photo-darkening effect) in the measured photon energy range (0.6–3.8 eV), depending on the ion fluence, energy and carbon content of the films. These effects could be attributed both to additional defect introduction and increased graphitization, as confirmed by Raman spectroscopy and infra-red (IR) optical transmission measurements. The optical contrast thus obtained (between implanted and unimplanted film material) could be made use of in the area of high-density optical data storage using focused high-energy He⁺ ion beams.     

A 220 GHz (G-Band) Microstrip MMIC Single-Ended Resistive Mixer

This letter presents the design and characterization of a 220 GHz microstrip monolithic microwave integrated circuit single-ended resistive mixer in a 0.1 GaAs mHEMT technology. A conversion loss as low as 8.7 dB is obtained, limited by the available local oscillator (LO) power (1.5 dBm) in the measurement setup. The radio frequency (RF) bandwidth is also limited by the measurement setup, but the mixer demonstrates a flat response over the measured 200 to 220 GHz frequency range. Furthermore, measured intermediate frequency bandwidth, 1-dB input compression point, LO-to-RF isolation, and reflection coefficients are presented and discussed.     

Solvent extraction of rosmarinic acid from lemon balm and concentration of extracts by nanofiltration: Effect of plant pre-treatment by supercritical carbon dioxide

The present work investigates a complex scheme of valuable components extraction from herbs and extracts concentration by nanofiltration. Two ethanol–water mixtures (50:50 and 80:20 (v/v)) have been used for solvent extraction of rosmarinic acid (RA) from dry lemon balm aerial parts and high recovery (up to 94%) has been obtained in three steps scheme. A positive impact of a preliminary treatment by supercritical CO₂ (in order to utilize the plant essential oil) on the successive RA extraction has been observed. The cross-linked polyimide membrane Duramem™ 200 has performed RA rejection of over 99% and reasonable flux at dead end nanofiltration pressure of 30 bar. This high rejection being independent of ethanol content in the solvent, supercritical pretreatment and RA concentration of the extracts has allowed to obtain nearly saturated retentate solutions (up to 19 g/L RA) and to reuse the permeates for lemon balm extraction in place of pure solvent. A RA content in the extracts dried total solid mass of 28 ± 2 % has been achieved.The additional resistance due to osmotic pressure difference and concentration polarization has been determined as a power function of retentate concentration with power value near to unity and approximately similar for the extracts and a model solution of RA.The study has confirmed the potential benefits of nanofiltration implementation in herbal extracts processing.     

An approach to online identification of Takagi-Sugeno fuzzy models.

An approach to the online learning of Takagi-Sugeno (TS) type models is proposed in the paper. It is based on a novel learning algorithm that recursively updates TS model structure and parameters by combining supervised and unsupervised learning. The rule-base and parameters of the TS model continually evolve by adding new rules with more summarization power and by modifying existing rules and parameters. In this way, the rule-base structure is inherited and up-dated when new data become available. By applying this learning concept to the TS model we arrive at a new type adaptive model called the Evolving Takagi-Sugeno model (ETS). The adaptive nature of these evolving TS models in combination with the highly transparent and compact form of fuzzy rules makes them a promising candidate for online modeling and control of complex processes, competitive to neural networks. The approach has been tested on data from an air-conditioning installation serving a real building. The results illustrate the viability and efficiency of the approach. The proposed concept, however, has significantly wider implications in a number of fields, including adaptive nonlinear control, fault detection and diagnostics, performance analysis, forecasting, knowledge extraction, robotics, behavior modeling.     

Nerve-plasty interventions on the facial nerve in the elderly patient--morphological evaluation of disappointing functional results]

Acute pesticide poisoning is a global health problem, especially in developing countries. Although Taiwan has quickly industrialized during the last several decades, pesticide use is still prevalent in the agricultural sector. We reviewed 187 consecutive hospitalized cases of the Provincial HsinChu Hospital from January 1989 through December 1995 to explore the determinants of acute pesticide poisoning in Metropolitan HsinChu. The annual incidence rate of acute pesticide poisoning was 3.2/100,000 with an overall fatality rate of 23% which was more severe than the rates found in developed countries. The major agents involved were organophosphates, and the major cause of poisoning was suicide. Alcohol abuse, history of major medical illnesses, and history of suicide were significantly associated with suicidal poisoning; quarrel was the immediate risk factor. Causes of poisoning (suicide vs non-suicide) and selection of the pesticides were major determinants of lethality. More stringent legislation and enforcement regarding the sale and distribution of extremely toxic pesticides are needed to reduce fatalities due to acute pesticide poisoning.