Birefringence of CuGa2S4 crystals

The interference of optical transmission spectra of thin CuGaS₂ single crystals is measured in E||c and E⊥c polarizations. The spectral dependencies of the refractive indexes n_o, n_e and Δn = n_o − n_e near the absorption edge have been determined from interference spectra. The intersection of refractive indexes at two wavelengths has been revealed at 300 K and 10 K. The characteristics of Band-Pass-Mode Filter and Band-Elimination-Mode Filter have been measured, which possess 7 narrow absorption (transmission) bands and represent a comb filter. The characteristics of these filters have been studied.     

Wastewater-based epidemiology to assess human exposure to personal care and household products – A review of biomarkers,analytical methods,and applications

Humans are nowadays exposed to numerous chemicals in our day-to-day life, including parabens, UV filters, phosphorous flame retardants/plasticizers, bisphenols, phthalates and alternative plasticizers, which can have different adverse effects to human health. Estimating human’s exposure to these potentially harmful substances is, therefore, of paramount importance. Human biomonitoring (HBM) is the existing approach to assess exposure to environmental contaminants, which relies on the analysis of specific human biomarkers (parent compounds and/or their metabolic products) in biological matrices from individuals. The main drawback is its implementation, which involves complex cohort studies. A novel approach, wastewater-based epidemiology (WBE), involves estimating exposure from the analysis of biomarkers in sewage (a pooled urine and feces sample of an entire population). One of the key challenges of WBE is the selection of biomarkers which are specific to human metabolism, excreted in sufficient amounts, and stable in sewage. So far, literature data on potential biomarkers for estimating exposure to these chemicals are scattered over numerous pharmacokinetic and HBM studies. Hence, this review provides a list of potential biomarkers of exposure to more than 30 widely used chemicals and report on their urinary excretion rates. Furthermore, the potential and challenges of WBE in this particular field is discussed through the review of pioneer WBE studies, which for the first time explored applicability of this novel approach to assess human exposure to environmental contaminants. In the future, WBE could be potentially applied as an “early warning system”, which could promptly identify communities with the highest exposure to environmental contaminants.     

Frequency selective surfaces for millimetre and submillimetre wave quasi optical demultiplexing

The purpose of this paper is to compare the filtering properties of drilled plate and printed element frequency selective surfaces in the range 80 – 800 GHz. Novel techniques for measuring and fabricating the devices are described, and close agreement is shown between numerical simulation and experimental results.     

A Gradient Flow Approach to Optimal Model Reduction of Discrete-Time Periodic Systems

This paper is concerned with the optimal model reduction for linear discrete periodic time-varying systems and digital filters. Specifically, for a given stable periodic time-varying model, we shall seek a lower order periodic time-varying model to approximate the original model in an optimal H ₂ norm sense. By orthogonal projections of the original model, we convert the optimal periodic model reduction problem into an unconstrained optimization problem. Two effective algorithms are then developed to solve the optimization problem. The algorithms ensure that the H ₂ cost decreases monotonically and converges to an optimal (local) solution. Numerical examples are given to demonstrate the computational efficiency of the proposed method. The present paper extends the optimal model reduction for linear time invariant systems to linear periodic discrete time-varying systems.     

Novel ultrasound contrast agents——Biodegradable poly(lactic acid) microcapsules

The different intensities of reflecting and scattering ultrasound signal at the tissue interface of the body can help to deliver the inner information and have proven their tremendous usefulness in medicine. Because it has a lot of advantages such as safety, wide application, good repetition, effi-cient detection, flexibility and economy, ultrasound diagnostics becomes the primary technology of modern medical imaging diagnostics and plays a key role in the modern diagnostic technol-ogy[1]. Alt…     

激光安全及激光防护镜近况

评述了激光器的潜在危险,简述了一般的激光安全预防措施,详细介绍了多种激光防护镜的新近发展。     

INFRARED MEASUREMENTS OF POSSIBLE IR FILTER MATERIALS

A Fourier Transform Infrared Spectrometer (FTS) was used to obtain the transmission spectra of candidate materials for use as infrared (IR) filters in cryogenic receivers. The data cover the range from 50 cm⁻¹ (∼1.5 THz), well below the peak of the 300 K black body spectrum, to 5000 cm⁻¹ (∼150 THz), Z-cut quartz, Goretex, Zitex G and Zitex A, High Density Polyethylene (HDPE), Teflon (PTFE), Fluorogold and Black Polyethylene were measured. The relative effectiveness of each material as a filter is determined by integrating the transmission spectrum multiplied by the Planck distribution to obtain a normalized attenuation for the mid-IR band. Measurements at both room temperature and 8 K are compared.     

Perfect and bipartite IMTL-algebras and disconnected rotations of prelinear semihoops

IMTL logic was introduced in [12] as a generalization of the infinitely-valued logic of Lukasiewicz, and in [11] it was proved to be the logic of left-continuous t-norms with an involutive negation and their residua. The structure of such t-norms is still not known. Nevertheless, Jenei introduced in [20] a new way to obtain rotation-invariant semigroups and, in particular, IMTL-algebras and left-continuous t-norm with an involutive negation, by means of the disconnected rotation method. In order to give an algebraic interpretation to this construction, we generalize the concepts of perfect, bipartite and local algebra used in the classification of MV-algebras to the wider variety of IMTL-algebras and we prove that perfect algebras are exactly those algebras obtained from a prelinear semihoop by Jenei's disconnected rotation. We also prove that the variety generated by all perfect IMTL-algebras is the variety of the IMTL-algebras that are bipartite by every maximal filter and we give equational axiomatizations for it.     

Novel Scheme for Narrow Band Fiber Filter System

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Science and technology with nuclear tracks in solids

Fission track dating has greatly expanded its usefulness to geology over the last 40 years. It is central to thermochronology—the use of shortened fission tracks to decipher the thermal history, movement, and provenance of rocks. When combined with other indicators, such as zircon color and (U–Th)/He, a range of temperatures from C to C can be studied. Combining fission track analysis with cosmogenic nuclide decay rates, one can study landscape development and denudation of passive margins. Technological applications have expanded from biological filters, radon mapping, and dosimetry to the use of ion track microtechnology in microlithography, micromachining by ion track etching, microscopic field emission tips, magnetic nanowires as magnetoresistive sensors, microfluidic devices, physiology of ion channels in single cells, and so on. In nuclear and particle physics, relatively insensitive glass detectors have been almost single-handedly responsible for our knowledge of cluster radioactivity, and plastic track detectors together with automated measuring systems have been used at the Bevalac, Brookhaven, CERN, and GSI, mainly to study fragmentation of high-energy heavy nuclei. Almost everything we know about the ultraheavy cosmic rays has been learned using Lexan on the Long Duration Exposure Facility and BP-1 phosphate glass on the Mir Station. New topics include development of calorimetric aerogels capable of measuring kinetic energies of hypervelocity interstellar and interplanetary dust grains in space and research on identification of strains of Bacillus spores by measurements of their size and swelling rates when humidified.