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Far Infrared (FIR) functionalized textile materials are enjoying a special attention nowadays, as a viable and practical solution for treating a wide range of medical conditions (relief of acute or chronic inflammation and circulatory problems, prevention of microbial infections, improvement of nervous system functions, reduction of skin lipids, improvement of blood circulation, removal of accumulated toxins by improving lymphatic circulation etc.). At the molecular level, FIR compounds and functionalized materials exert strong rotational and vibrational effects, with beneficial biological potential. These materials are based on the principle of absorbing light energy and then irradiating this energy back into the body at specific wavelengths. FIR functionalized textile materials are a new category of functional textiles that have the potential to improve well-being and health. Present paper explored the antimicrobial potential of four textile materials, functionalized with FIR, UV protection and antimicrobial functionalization compounds, tested according to two methods for assessment of antimicrobial character: a testing method in dynamic conditions and a testing method in static conditions. The evaluation of the antimicrobial character showed very good rates of reduction of the microbial population, of the functionalized textile materials, following the testing on four strains of pathogenic fungi: Candida albicans, Epydermophyton floccosum, Tricophyton interdigitale and Aspergillus niger, with reduction rates between 76.16% and 96.06%.

Traditional uses of clay as medicine started in prehistoric times (Aboriginal times). Natural clays have been used in ancient and modern medicine, but the mechanism that makes certain clays lethal to bacterial pathogens has not been yet identified. The aim of this paper is to identify the proper clays that could be used in textile industry for improving textiles` functionality, based on the information extracted from literature. It is important, to differentiate between the properties that make a clay ‘healing’, versus what makes it ‘antibacterial’. So far, literature is abundant in reports regarding ‘healing’ clays, but, when tested against pathogens in vitro and compared to controls, they do not appear to have bactericidal properties. The studies carried out up to this point established that the physical adsorption of water and organic matter is the main feature which leads to healing properties of clays; however, the chemical interaction between clay and bacteria has received less attention. Clay properties, with potential application in medicine, have recently been started to be investigated and the results indicate that certain natural clays can have noticeable and extremely specific effects on microbial colonies. Further studies will be directed towards the characterization of the selected ‘claytextile’ pairs.

Obtaining high-quality materials, based on nanocrystals, at low temperatures is one of the current challenges for opening new paths in improving and developing functional devices in nanoscale electronics and optoelectronics. Here we report a detailed investigation of the optimization of parameters for the in situ synthesis of thin films with high Ge content (50 %) into SiO2. Crystalline Ge nanoparticles were directly formed during co-deposition of SiO2 and Ge on substrates at 300, 400 and 500 °C. Using this approach, effects related to Ge–Ge spacing are emphasized through a significant improvement of the spatial distribution of the Ge nanoparticles and by avoiding multi-step fabrication processes or Ge loss. The influence of the preparation conditions on structural, electrical and optical properties of the fabricated nanostructures was studied by X-ray diffraction, transmission electron microscopy, electrical measurements in dark or under illumination and response time investigations. Finally, we demonstrate the feasibility of the procedure by the means of an Al/n-Si/Ge:SiO2/ITO photodetector test structure. The structures, investigated at room temperature, show superior performance, high photoresponse gain, high responsivity (about 7 AW−1), fast response time (0.5 µs at 4 kHz) and great optoelectronic conversion efficiency of 900% in a wide operation bandwidth, from 450 to 1300 nm. The obtained photoresponse gain and the spectral width are attributed mainly to the high Ge content packed into a SiO2 matrix showing the direct connection between synthesis and optical properties of the tested nanostructures. Our deposition approach put in evidence the great potential of Ge nanoparticles embedded in a SiO2 matrix for hybrid integration, as they may be employed in structures and devices individually or with other materials, hence the possibility of fabricating various heterojunctions on Si, glass or flexible substrates for future development of Si-based integrated optoelectronics.

Since the beginning, Mobile Bed Biofilm Reactor (MBBR) technology has been extensively used, both at the level of small on-site treatment units and at industrial scale. Moreover, this technology represents a starting point for many researches aimed at improving performance, such as the use of microorganisms, enrichment with anammox bacteria to accelerate nitrogen removal and more. Within the present paper, a new generation of carriers (consisting of a mix of high-density polyethylene + talcum + cellulose) was bio-augmented with a WRF (White Rot Fungi) strain, namely Cerioporus squamosus, in static conditions (data not shown in this paper). The wastewater, targeted for treatment, originated from National R&D Institute for Textile and Leather, INCDTP Bucharest, leather subsidiary, Leather and Footwear Research Institute, technological flux, characterized by high tannins concentration, and cellulosic content. Wastewater treatment aimed the reduction of COD value, as a water quality parameter, with satisfactory results, obtaining a percentage reduction rate of 48.53%. Also, GC-MS chromatography analysis was carried out on five vegetal tannins, used in leather treatment, highlighting main compounds for Mimosa, Chestnut, Gambier, Myrobalan and Quebracho natural tannins.

InterDigitated Electrodes (IDEs) is a generic platform for a wide range of diverse applications with their implementation in sensing modules being a major one. We propose the use of IDCs with deep sub-micron critical dimension; equally spaced electrodes of 200 nm width for enhanced sensing performance and also the method of fabrication thereof. The transducer configuration was studied theoretically with a finite element method simulation by using COMSOL Multiphysics. The miniaturization of the IDEs up to 200 nm critical dimension with an adequate sensing area for the deposition of the polymeric materials is considered beneficial in terms of sensitivity gain. The IDCs were designed to deliver capacitance values of few pF in order to be compatible with already developed miniaturized low-power readout electronics. The transducers fabrication is performed with conventional microelectronic/micromachining processing and then coated with several semi-selective polymeric films. Besides the fabrication of multiple sensor arrays (chips) on the same silicon wafer, the miniaturization offers the integration with the readout electronics on the same chip. The evaluation of the sensing performance of the semi-selective polymer coated sensors is performed upon exposure to vapours of pure and binary mixtures of VOCs and humidity in various concentrations. The sensors demonstrate high sensitivity to the examined analytes as a result of the miniaturization, while their semi-selectivity is a key for applications in complex vapour environment discrimination.

In Moving Bed Biofilm Reactors (MBBR) the biofilm grows protected within small plastic carriers (known as biofilm carriers), which are designed with high internal surface area. The biological wastewater treatment process consists of adding biofilm carriers in aerated or anoxic tanks to support biofilm attachment and growth. Some of the authors conceived, designed and realised an improved carrier (new shape and material) for fungal biofilm development. The improved biofilm carriers were tested in laboratory conditions and good results were obtained. This new biofilm carrier will be used to treat cellulosic (tannery and papermill) wastewaters and is grafted with cellulose fibers for the self-sustainability of the fungal biomass. This will facilitate substrate adhesion, due to biochemical capabilities of the selected strains, which involve secretion of extracellular enzymes, that can break down substrate by combined action of several degradative processes, such as demethylation, oxidative cleavage of the propane side chain, cleavage of ether bonds between monomers etc.

The paper describes the dynamic behavior of STATCOM device and a SVC device connected in the National Grid and shows simulation results. The operation principle of the two devices will be presented. The simulations were made using specialized software Eurostag. Various operation scenarios were simulated in order to show the impact on the transmission power grid.

Transmission electron microscopy and X-ray photoelectron spectroscopy analyses are performed to investigate Ge nanoparticles embedded in an amorphous SiO2 matrix. GeSiO thin films are prepared by two methods, sol–gel and radio frequency magnetron sputtering. After the deposition, the sol–gel films are annealed in either N2 (at 1 atm and 800 °C) or H2 (at 2 atm and 500 °C), and the sputtered films in H2 (at 2 atm and 500 °C), to allow Ge segregation. Amorphous Ge-rich nanoparticles (3–7 nm size) are observed in sol–gel films. Crystalline Ge nanoparticles in the high pressure tetragonal phase (10–50 nm size) are identified in the sputtered films. The size of the nanoparticles increases with Ge concentration in the volume of the film. At the film surface, the Ge concentration is much larger that in the volume for both sol–gel and sputtered films. At the same time, at the film surface, only oxidized Ge is observed.

The influence of the gate voltage on photoconductivity in p–Si/SiO 2 /(nano)crystalline PbS, Metal-Oxide Semiconductor Field-Effect Transistor (MOSFET ) -like structures is investigated. The effect on the photo-signal in the wavelength range 500–1180 nm is opposite compared to the effect in the wavelength range 1600–2500 nm: a negative gate voltage increases the signal in the short wavelength range and decreases it for the long wavelength range. The opposite is valid for a positive gate bias. An on-off ratio better than 85 times is obtained for the spectral range 500–1180 nm, corresponding to the absorption in p–Si and better than 3.5 times for the spectral range 1600–2500 nm corresponding to the absorption in the (nano)crystalline PbS region, respectively.

The nano-crystalline PbS/ n -Si heterostructure was studied using photocurrent spectra, I – V and C – V characteristics and admittance spectroscopy. The frequency dependent junction capacitance and conductance measurements show the presence of two contributions: first, a defect related mechanism which we attribute to a deep trap level with a large cross-section in nano-crystals with smaller sizes around 5 nm at the interface with Si and a second mechanism with an activation energy of about 250 meV, attributed to carrier transport in relatively large PbS grains of about 15 nm in size.

We designed a silicon-processing compatible, simple, and cheap device operating at a power down to sub-muW. It has a pillar-shaped structure with a nanoscopic (10-100 nm in size) conductive link (the so-called antifuse) created between two electrodes separated by a SiO 2 layer. The device exhibits a diode-like behavior due to the depletion effects in the mono-silicon pillar. The device is capable of maintaining a microscopic hot-surface area of several hundreds degrees centigrade. The size of the hot area and its temperature can be manipulated by the sign of the applied bias. Two different heat-generation mechanisms (i.e., dissipation at a resistor and a non-radiative recombination of carriers) are proposed and modelled. Such a device can be used as a heat source, as a light source, and as a sensitive detector of light and heat. In this paper, we describe thermo-electrical properties of the fabricated devices and demonstrate their feasibility to perform as gas-, adsorption-, desorption sensors, and as units for activating chemisorption/decomposition of gaseous precursors, i.e., micro-reactors

In this paper we describe a new, simple, and cheap silicon sensor operating at a high temperature of about 1000 K and consuming a very low power of a few milliwatts. We developed a silicon-processing compatible, simple, and low-cost method for processing thermally isolated suspended membranes. This makes the technology more compatible with standard complementary metal oxide semiconductor (CMOS) technology. The essential part of the device is a conductive link of several nanometers in size (the so-called antifuse) formed in between two polysilicon electrodes separated by a thin SiO2 layer. An advantage of the proposed concept is decoupling (i.e., independent control) of the electrical and thermal resistances. The device can be utilized in chemical sensors or chemical microreactors requiring high temperature and very low power consumption, e.g., in portable battery-operated systems. As a direct application, we demonstrate a gas sensor (i.e., Pellistor) for hydrocarbons (butane, methane, propane, etc.) based on temperature changes due to the catalytic combustion of hydrocarbons. The power consumed by our device is about 2% of the power consumed by conventional Pellistors.

Lowering the temperature of crystallization by deposition of thin films on a heated substrate represents the easiest way to find new means to develop and improve new working devices based on nanocrystals embedded in thin films. The improvements are strongly related with the increasing of operation speed, substantially decreasing the energy consumption and reducing unit fabrication costs of the respective semiconductor devices. This approach avoids major problems, such as those related to diffusion or difficulties in controlling nanocrystallites size, which appear during thermal treatments at high temperatures after deposition. This article reports on a significant progress given by structuring Ge nanocrystals (Ge-NCs) embedded in silicon dioxide (SiO2) thin films by heating the substrate at 400 °C during co-deposition of Ge and SiO2 by magnetron sputtering. As a proof-of-concept, a Si/Ge-NCs:SiO2 photo-sensitive structure was fabricated thereof and characterized. The structure shows superior performance on broad operation bandwidth from visible to near-infrared, as strong rectification properties in dark, significant current rise in the inversion mode when illuminated, high responsivity, high photo-detectivity of 1014 Jones, quick response and significant conversion efficiency with peak value reaching 850% at −1 V and about 1000 nm. This simple preparation approach brings an important contribution to the effort of structuring Ge nanocrystallites in SiO2 thin films at a lower temperature for the purpose of using these materials for devices in optoelectronics, solar cells and electronics on flexible substrates.

N-type P-doped silicon single crystals with resistivity higher than 8000 Ucm were irradiated with 127I6+ ions of 28 MeV kinetic energy. The penetration of the ions through the target and the processes of energy loss were simulated using the CTRIM Monte Carlo code, and point defect production was calculated in the frame of our diffusion-reaction model. Trapping phenomena were investigated using the method of thermally stimulated currents without applied bias. The modeling of the current-temperature curves takes into consideration both point defects and stress-type trapping centers, produced by the ions stopped into the crystal.

The long time degradation produced by particles and ions in crystalline materials used for devices to work in space, or for detectors in HEP and astroparticles, is characterised by the non-ionising energy loss, which is calculated in the frame of an analytical model. The transient phenomena as short time degradation are characterised by the time and space dependencies of the lattice and electron temperatures near the projectile trajectory. These processes are considered in the frame of a thermal spike model, which takes into account both ionization and nuclear energy loss processes.

The thermal spike model which takes into account both ionization and nuclear energy loss processes of the projectile as distinct electronic and atomic heat sources is used to describe transient processes induced by ions in silicon. The time and space dependencies of the lattice and electron temperatures near the projectile trajectory are calculated. The contribution of the rise in temperature on defect formation and annealing is considered.

A comparative study of photodetector performance for nano- and micro-crystalline PbS thin layers is presented. Both types of PbS films were obtained using the Chemical Bath Deposition method. To prepare nano-crystalline thin films we used a short reaction time with no doping Bi added. At low levels of irradiance (0.1 m W/cm2) and room temperature (RT), the macro-crystalline PbS outperforms its nano- crystalline counterpart, by a factor of 6 for the value of DeltaR/Rdark However the nano-crystalline photodetectors show significantly lower optical quenching for large values of irradiance (ap 500 mW/cm2) at RT and better DeltaR/Rdark performance at lower temperature, with an optimum temperature of 150 K. The low frequency noise behavior is a superposition of 1/f flicker noise at low frequency and generation-recombination and thermal noise at higher frequency. The proportionality factor between the 1/f noise and the DC dark current for the series resistor is 1.5 times larger for the nano-crystalline photodetector at room temperature.

We designed a CMOS compatible hot-surface silicon device operating at a power down to sub-μW. It has a pillarshaped structure with a nano-size (10-100 nm) conductive link between the electrodes separated by a SiO2 layer. The device is capable of maintaining a μm-size hot-surface area of several hundred degrees centigrade due to non-radiative recombination of carriers in a thin (13 nm) poly silicon surface layer. Such a device can be used as a light source, a heat source, as well as a sensitive detector of light and heat. As a direct application, we demonstrate the feasibility to perform as an adsorption-desorption sensor, and as a unit for activating chemisorption/decomposition (i.e. micro-reactor).

This work employs the idea of making micro-scale hot-surface devices (e.g. sensors, flow meters, micro reactors, etc) based on generation of heat due to nonradiative recombination of carriers in a thin (13 nm) poly silicon surface layer. An important part of the device is a nano-scale (10-100 nm) conductive link created between two polysilicon electrodes separated by a dielectric (a capacitor-like structure). Using this approach, we designed and realized a new silicon device with the hot surface reduced to a sub-/spl mu/m-size area, operating at very low power down to sub-/spl mu/W. From the experiments, such a device can be used as a heat source as well as a sensitive detector of heat. In this paper, we describe the thermo-electrical properties of fabricated devices and demonstrate their feasibility to perform as gas- adsorption- desorption sensors operating at extremely low power consumption.

Anomalous anatomic location of a large venous system is a very important assessment before aortic operations. Ours was an anatomical finding of a case of preaortic iliac confluence, a variation also known as 'marsupial vena cava'. As abdominal aortic surgery is currently performed routinely, rare anatomical anomalies must be spotted, in order to avoid injury to surrounding organs.

The paper presents a low confinement laser diode structure designed for high power operation. The attenuation coefficient is lower than 1 cm/sup -1/ and is probably due to free carrier absorption on injected carriers. The threshold current density is 800 A/cm/sup 2/ and the differential efficiency is 36% (both uncoated facets) for 5 mm long devices. The internal efficiency is 50%. All values are measured in pulsed conditions (100 ns pulse width, 1 kHz repetition rate).

Summary form only given. Vertical cavity surface emitting laser diodes (VCSELs) are promising devices for optical pump sources due to their circularly symmetric beam profile. Their planar geometry also makes them uniquely suitable for ultra-compact, diode pumped lasers and laser arrays in which the pump source is directly bonded to the microchip. A further feature of the VCSELs is that their emitting aperture can be controlled to provide spatial variation of the pump power. We present, for the first time to our knowledge, a VCSEL pumped, plano-plano cavity, solid state laser and study the influence of the pump laser diameter on the operating characteristics.

This paper studies, both theoretically and experimentally, stress-induced effects on the lateral far-field behavior for ridge-type semiconductor laser diodes where anodic oxide is used for the definition of the stripe width. These effects consist of antiguiding under the stripe region, and of two positive waveguiding features near the stripe edges. For low-threshold devices, these effects may be more important than thermal effects, depending on the stress in the oxide. They put a lower limit on the built-in index guiding to be introduced by lateral etch outside the ridge region in order to maintain fundamental mode operation for wider stripes. The magnitude of these effects may be as large as /spl Delta/n/sub ef/=1/spl times/10/sup -3/. An analytical mathematical model is deduced for computing stresses and strains for a certain ridge-shaped interface which bounds the elastic medium.

A low-confinement asymmetric GaAs-AlGaAs double-quantum-well molecular-beam-epitaxy grown laser diode structure with optical trap layer is characterized, The value of the internal absorption coefficient is as low as 1.4 cm/sup -1/, while keeping the series resistance at values comparable cm with symmetrical quantum-well gradient index structures in the same material system. Uncoated devices show COD values of 35 mW//spl mu/m. If coated, this should scale to about 90 mW//spl mu/m. The threshold current density is about 1000 A/cm/sup 2/ for 2-mm-long devices and a considerable part of it is probably due to recombination in the optical trap layer. Fundamental mode operation is limited to 120-180 mW for 6.5-/spl mu/m-wide ridge waveguide uncoated devices and to 200-300 mW for 13.5-/spl mu/m-wide ones, because of thermal waveguiding effects. These values are measured under pulsed conditions, 10 /spl mu/s/l ms.

This paper reports experimental results on single quantum-well separate confinement heterostructures (SQW SCH) with low-confinement factor, designed for very high-power operation. The maximum power output for AR/HR coated 3-mm-long devices, measured in very short pulsed conditions (100 ns/1 kHz), from 10-/spl mu/m-wide stripes was as high as 6.4 W before catastrophic optical degradation. If scaled to continuous-wave (CW) conditions, this value would be 800-1100 MW, which would mean a factor of 22.7 times more than reported for the best devices with normal design for threshold minimization. The absorption coefficient for the symmetrical structure is as low as 1.1 cm/sup -1/, in spite of the low trapping efficiency of carriers in the quantum well (QW). The maximum differential efficiency is 40% (both faces, uncoated devices) for symmetrical structure and 33% for the asymmetrical one (all measurements in pulsed conditions). Threshold current densities were 800 A/cm/sup 2/ for 5-mm-long devices in the symmetrical case and 2200 A/cm/sup 2/ in the asymmetrical one. The effects of inefficient carrier trapping in the QW on the threshold current densities and differential efficiency are discussed.

This paper presents the optical field behaviour of relatively large stripes, long laser diodes. The devices were designed to operate in the fundamental lateral mode. The stripe width, of order of 16 /spl mu/m, involves a very low refractive index step at the ridge edges and the operation of the diode in the weak index guided regime. This index profile and subsequently, the optical field distribution is very easily disturbed by carrier injection or by temperature. The paper aims to characterise the influence of direct current intensity on lateral far field.

The effects of 5 × 1011 cm−2 6+I127 ions of 28 MeV kinetic energy on high resistivity (100) Si were studied. The profile of primary defects was simulated. The defects produced by irradiation which act as traps were investigated. Thermally stimulated current measurements without externally applied bias were used, and for this the traps were charged by illuminating samples with 1000, 800, and 400 nm wavelengths. The discharge currents were recorded and modeled, and therefore the parameters of the traps were determined. The presence of I ions, heavier than Si, stopped into the target was modeled as a temperature independent electric field.

It was recently proposed,1,2 that the power density related to the window width (in W/μm) of a laser diode can be substantially improved using a low confinement epitaxial structure. Keeping a reasonable high value of the intrinsic gain in the active region, a low confinement structure shall work also with a low modal gain value. The power optimization process is essentially connected to the attenuation coefficient of the laser waveguide α. When operating with an α value around 1 cm−1 and pursuing a high differential efficiency, the modal gain should have a value around 5 cm−1 and the laser length should be increased accordingly.2 A beneficial consequence of the low modal gain value is the possibility to increase the stripe width while preserving well the operation in the fundamental lateral mode above the threshold.

Analysis of 800 strabismic children, in the out-patient follow-up, shows a frequency of congenital strabismus of 15%. In a great number of them, the causes were neurogenous. The anamnesis showed that 80 of them had a suffering at birth, and in 42 a defective neuropsychic evolution was found. 40 children were prematures and 30 had not the weight limit at birth. The strabismic deviation was larger than 15 degrees in 83% of the cases, and amblyopia was not frequent. Examples are given of 10 various observations of oculomotor pareses. The treatment was, generally, surgical and was applied early, before consolidation of the abnormal retinal correspondence.

This paper demonstrates an analytical expression for the quasistatic capacitance of a quantum dot layer embedded in a junction, where the reverse bias is used to discharge the initially occupied energy levels. This analysis can be used to determine the position and the Gaussian homogeneous broadening of the energy levels in the conduction band, and is applied for an InGaAs/GaAs quantum dot structure grown by metal organic chemical vapor deposition. It is shown that the Gaussian broadening of the conduction band levels is significantly larger than the broadening of the interband photoluminescence (PL) transitions involving both conduction and hole states. The analysis also reveals a contribution from the wetting layer both in PL and modeled C-V profiles which is much stronger than in typical molecular beam epitaxy grown dots. The presence of a built-in local field oriented from the apex of the dot toward its base, contrary to the direction expected for a strained dot with uniform composition (negative dipo...

Leakage currents determine bumps in the capacitance-voltage characteristics of metal-oxide-semiconductor-type heterostructures with capacitance values larger than the insulator capacitance. A nearly parallel shift with frequency is also observed. These aspects are connected with the presence of a high density of interface states. We illustrate these effects for the case of nano-PbS∕SiO2∕Si heterostructures. The phenomena were simulated and we propose a method to quickly estimate the interface state density level of a heterostructure when leakage channels are present.

High power continuous wave output from diode lasers using low loss, low confinement, asymmetric structures is demonstrated. An asymmetric structure with an optical trap layer was grown by metal organic vapour phase epitaxy. Gain guided 50 µm wide stripe 1–3 mm long diode lasers were studied. 1.8 W of continuous wave optical power per uncoated facet was obtained at an injection current of 4.7 A (36 mW/µm). The threshold current density is 270–400 A/cm2.