Solid-state Components Research Articles

MEMS modulator to control optical system network signalling

MEMs technologies have evolved significantly in recent times, including MEMs designed for optical telecommunications. In many cases, MEMs components are integrated with other solid state components to realise micro opto electronic mechanical systems (MOEMS). An MEMS optical modulator has been designed utilising electrostatic operation, enabling many qualities suitable for optical network applications, including activation speed and low power consumption. MEMS geometry and analytical mode models were developed and applications performance estimated including multiphysics phenomena. Finite element analysis performed using the software suite, COMSOL®, performing static and dynamic simulations in time and frequency domains. The proposal is that the MEMS modulator is integrated with other optical components in a hermetically sealed vacuum environment, resulting in a lightly damped response with decaying oscillation. A two-step drive signal was developed and simulated using the multi-domain, simulation package SIMULINK®. The optimised MEMS design and two-step driver realised an MEMS optical modulator meeting the specification.

A low-cost microcontroller-based system to monitor crop temperature and water status

A prototype system was developed and constructed for automating the measurement and recording of canopy-, soil-, and air temperature, and soil moisture status in cropped fields. The system consists of a microcontroller-based circuit with solid-state components for handling clock/calendar, sensor power, and data storage and retrieval functions. Sensors, including an analog soil moisture sensor, analog and digital temperature sensors, and a digital infrared thermometer, are widely available and inexpensive. The circuit board and sensor assemblies require approximately 4 h to construct and test, and material costs totaled approximately US$84. Systems were built and tested during the 2009 growing season in a corn field to evaluate performance and suitability under local conditions. The sensors performed according to manufacturers’ specifications, with accuracies of ±0.4 °C, ±1.4 °C, and ±0.3 °C for air-, soil-, and canopy-temperature measurements, respectively. Soil moisture sensors were calibrated and provided measurements within ±2 kPa of the manufacturer's values. Reliability of data collection and storage averaged 91%, with most bad or missing data occurring during periods of inclement weather and electrostatic interference.

Power-Frequency Voltage Withstand Characteristics of Insulations of Substation Secondary Systems

The insulation of secondary system in substation, including secondary cables and devices, have to endure the high ac power-frequency voltage during the short-circuit fault. The ac withstand characteristics of the secondary cables and devices are experimentally investigated and discussed in this paper. The insulation breakdown mechanism of relays can be classified into three modes: air gap breakdown, creeping discharge, and solid insulation breakdown, that of the microcomputer protection device is solid state component damage. The ac power-frequency breakdown voltages of the microcomputer protection device, the small-size electromagnetic and solid-state relays all are as low as about 2 kV. The statistic method to obtain the withstand voltage of long communication cable from experimental data of short cables is proposed. The minimum 3-s withstand voltages of secondary system are 6.5 kV and 2 kV, respectively, this should be considered in substation design. What's more, the volt-second characteristics of the power-frequency withstand voltage of the secondary cables and devices are analyzed and compared in detail, which would be important in the selection of secondary cables and devices. At last, the method how to guarantee high ac breakdown voltage of electromagnetic and solid-state relays and microcomputer protection device is suggested.

Techniques to Develop High Radiation Tolerant Solid State Devices and Their Uses

Desinging the solid state electronic devices and components by using the radioactive material for their fabrication(uranaium dioxide) and the dielectric isolation process provides the precise label of stability over high temperature range .Recently there was a failure of india’s maiden lunar exploration mission in which ISRO used CHANDRAYAAN-1 as a space craft on AUGUST 29 2009.main cause of failure was that of temperature variation(-50c to 120c) which lead the malfunctioning of SENSORS . Lunar spacecrafts had ONBOARD two star sensors with one as a backup to determine the orientation or attitude because of all the malfunctioning they had failed.Use of high radiation tolerant solid state devices and the use Radioactive material in fabrication technology provides suitable measures to avoid such failure of electronics devices by temperature variation. The full text of the article is not available in the cache. Kindly refer the IJCA digital library at www.ijcaonline.org for the complete article. In case, you face problems while downloading the full-text, please send a mail to editor at editor@ijcaonline.org

Large and dynamical tuning of a chalcogenide Fabry-Perot cavity mode by temperature modulation

Te-enriched chalcogenide glass Ge(15)As(25)Se(15)Te(45) (GAST) is synthesized, thermo-optically characterized and used to fabricate a one dimensional photonic crystal cavity mode that is dynamically and reversibly tuned by temperature modulation. The optical cavity mode is designed using GAST and As(2)S(3) glasses after fully determining their temperature dependence of the complex refractive indices in the visible and near infrared spectrum using spectroscopic ellipsometry. By making use of the very large thermo-optic coefficient (dn/dT = 4 x 10(-4)/ degrees C) of GAST glass at 1.2 mum, the cavity mode of the multilayer was tuned reversibly more than 16 nm, which is, to the best of our knowledge, an order of magnitude larger for this kind of cavity modulation. Wide and dynamical spectral tuning of low bandgap chalcogenide glasses via temperature modulation can be utilized in photonic crystal based integrated optics, quantum dot resonance matching, solid state and gas laser components, and infrared photonic crystal fibers.

Measurement of the density of magnetized fusion plasma using microwave reflectometry

About 25 years have elapsed since the first measurement by a FW-CW (called fast sweeping) reflectometer of the electronic density in magnetized fusion plasma. Substituting tube sources with solid-state components has resulted in a decrease of the sweeping time from the millisecond to the microsecond range. Based on voltage control oscillators and on active frequency multipliers, four profile reflectometers covering the range 33–155 GHz are in operation on Tore-Supra tokamak. Their originality is the use of one source for the launched and reference signal, although the detection is heterodyne. Indeed, a single side band modulator shifts the launched frequency ahead of frequency multipliers. With a sweeping time comparable to the plasma turbulence characteristic time the density profile is frozen. The density profile is then reliably measured with high radial and temporal resolution.

Fast-charging compact seed source for magnetic flux compression generators

Flux compression generators (FCGs) are some of the most attractive sources of single-use compact pulsed power available today due to their high energy density output and mobility. Driving FCGs requires some seed energy, which is typically provided by applying a high seed current, usually in the kiloampere range for midsized helical FCGs. This initial current is supplied by a high-current seed source that is capable of driving an inductive load. High-current seed sources have typically been comprised of discharging large capacitors using spark gaps and overvoltage triggering mechanisms to provide the prime power for FCGs. This paper will discuss a recent design of a self-contained (battery powered with full charge time less than 40 s), single-use compact seed source (CSS) using solid-state components for the switching scheme. The CSS developed is a system (0.005 m(3) volume and weighing 3.9 kg) capable of delivering over 360 J ( approximately 12 kA) into a 5.20 muH load with a trigger energy of microjoules at the TTL triggering level. The newly designed solid-state switching scheme of the CSS incorporates off-the-shelf high-voltage semiconductor components that minimize system cost and size as necessary for a single-use application. A detailed evaluation of the CSS is presented primarily focusing on the switching mechanics and experimental characterization of the solid-state components used in the system.

A monolithically integrated CMOS labchip using sensor devices

A new concept for a monolithic labchip platform to combine standard CMOS-integrated circuit technology and novel solid-state components is presented. The capability to perform laboratory analysis operations on small-scale labchip devices holds exceptional advantages compared to commonly used diagnostic instrumentation. The objective is to improve cost-efficiency, performance and functionality of chemical or biological systems on-a-chip by increasing the level of integration and miniaturization. The integration of hydrogenated amorphous silicon color sensors enables a novel combinatoric labchip-based chemical verification method in a specifically arranged microarray of capillaries and sensors. To test the labchip functionality, results about an electrophoretic separation as well as a pH-sensitive luminescent sensor complex are shown.

Optofluidic dye lasers

Optofluidic dye lasers are microfabricated liquid dye lasers enabled by the microfluidics technology. The integration of dye lasers with microfluidics not only facilitates the implementation of complete “lab-on-a-chip” systems, but also allows the dynamical control of the laser properties which is not achievable with solid-state optical components. We review the recent demonstrations of on-chip liquid dye lasers and some of the pre-microfluidics era microscopic dye lasers which are also amenable to microfluidic implementation. Potential applications and future directions are discussed.

Solid-state gyrotron body power supply, test results

A 170 GHz, 2 MW, steady-state gyrotron is being developed in collaboration between European research associations and industries to be used for the electron cyclotron resonance heating (ECRH) system of ITER, the gyrotron is presently in the prototype state. EFDA entrusted ENEA with the design of a new power supply for the gyrotron's body; in which, the traditional power vacuum tubes are replaced with solid-state components (IGBT); furthermore ENEA had the task of developing the new body power supply (BPS), following the initial conceptual design. The BPS is formed by 50 identical bidirectional (in current) modules, connected in series; the BPS's control system regulates the output voltage by changing the modulation index. OCEM Spa, under ENEA's supervision, has manufactured the BPS. Tests, done at the start of this year, showed the substantial agreement between the initial technical specifications and the values achieved. Particularly the ramp-up/down-emergency time (50–10 μs), the accuracy (±0.5%), the sine wave modulation (45–20 kV at 5 kHz) and the maximum phase shift (<10°) have been tested. In the article, the new stair-way modulation (SWM) scheme will be sketched and the test results will be described in detail.

The Red Rectangle: Solid State Components of Varying Composition in the Outflow

We report the discovery of broad mid-infrared resonances in the outer regions of the Red Rectangle outflow (Markwick-Kemper et al. 2005). The peak position and the strength of the resonances vary spatially, but the full width at half maximum, as well as the shape of the feature, appears remarkably constant. While emission due to polycyclic aromatic hydrocarbons (PAHs) is also present at these locations, we show that PAHs cannot be the carriers of these new components. Instead, we argue that these resonances are caused by solid state components, perhaps simple Mg-Fe-oxides. The presence of such O-rich species in the otherwise C-rich outflows further complicates the picture of the formation and chemistry of the Red Rectangle nebula.

31.4: Low Cost, Display-Based, Photonic Touch Interface with Advanced Functionality

We describe a new display-based, photonic hand-machine interface technology based on photonic detection of finger positions and forces. The interface, constructed solely from solid-state components, detects multiple finger contacts and ten additional force and position parameters per finger. A thin, transparent, low-cost embodiment suitable for direct integration onto displays at the factory is also described.

AGA technical review on the clinical use of esophageal manometry

AGA technical review on the clinical use of esophageal manometry

Solid-state power supply for gas lasers

A novel pulsed power supply for gas lasers is presented. The device uses only solid state components and is based on a capacitor bank discharge. Fast switching of the discharge is triggered by an insulated gate bipolar transistor. The terminal section of the power supply is a transformer designed to match the reactive capacitance of a gas discharge. Strokes up to 30 kV and 30 mA are achieved across the secondary windings of this transformer. The power supply delivers high voltage pulses with a duration between 0.5 and 50 μs and a repetition rate up to some kHz. The power supply has been tested on a longitudinal discharge quasi-cw regime CO2 laser. Laser pulses were generated with a duration down to the microseconds region, a peak power exceeding some kilowatts, and a repetition rate ranging from 200 Hz to a few kHz.

Advances of Reflectometry on Tore-Supra: From Edge Density Profile to Core Density Fluctuations

A new generation of broadband reflectometers based on solid state components has been installed on Tore-Supra. With reflectometers covering the range 50 to 155 GHz, the whole plasma can be scanned. Two X-mode reflectometers (V and W band) are dedicated to electron density profile measurements. Diagnostics are operated routinely with an automatic algorithm to reconstruct the density profile from shot to shot. A fast acquisition mode is available to study short time plasma evolution. For turbulence and transport studies, a third reflectometer operating between 105 and 155 GHz measures density fluctuations in the plasma centre. Sensitive to large scales, it can retrieve density perturbation due to MHD modes or broadband turbulence. Lastly, a Doppler reflectometer, based on back scattering, is being installed for measuring the poloidal rotation and fluctuations amplitude at higher wave numbers.

Advanced Electromagnetic Modelling of Multilayer Monolithic Microwave Integrated Circuit

Lately considerable research activity has been centered on the development of optical and solid state components and devices which use inhomogeneous materials with a continuous variation of the electromagnetic parameters. In this contribution we consider the analysis of monolithic microwave integrated circuits (MMICs) with substrates whose relative permittivity continuously varies along the stratification axis. We propose a new, very efficient combined spectral domain-moment method formulation based on the derivation in a closed analytical form of the spectral electric dyadic Green's function. We, finally, present an application of the new technique to the design of practical, high efficient MMIC components.

Extensional detachment faulting and core-complex formation in the southern Barberton granite–greenstone terrain, South Africa: evidence for a 3.2 Ga orogenic collapse

Abstract The Barberton greenstone belt in South Africa is an Early- to Mid-Archaean, very low-grade metamorphic supracrustal belt that is bordered in the south by a mid- to lower crustal gneiss terrain. Detailed mapping of the contacts between the supracrustal and gneiss domains along the southern margin of the greenstone belt shows that the supracrustal rocks are separated from the high-grade metamorphic gneiss terrain by an extensional detachment that is situated at and close to the base of the belt. The extensional detachment is approximately 1-km wide and its location corresponds with the heterogeneous, melange-like rocks of the Theespruit Formation. Within the detachment zone, two main strain regimes can be distinguished. Amphibolite-facies rocks at and below the granite–greenstone contacts are characterized by rodded gneisses and strongly lineated amphibolite-facies mylonites. The bulk constrictional deformation at these lower structural levels records, in a subhorizontal orientation, the vertical shortening and horizontal, NE–SW directed stretching of the mid-crustal rocks. The prolate, coaxial fabrics are overprinted by greenschist-facies mylonites at higher structural levels that cut progressively deeper into the underlying high-grade basement rocks. These mylonites have developed during non-coaxial strain and kinematic indicators consistently point to a top-to-the-NE sense of movement of the greenstone sequence with respect to the lower structural levels. This relationship between bulk coaxial NE–SW stretching of mid-crustal basement rocks and non-coaxial, top-to-the-NE shearing along retrograde mylonites at upper crustal levels is consistent with an extensional orogenic collapse of the belt and the concomittant exhumation of deeper crustal levels. The exhumation was initiated under amphibolite-facies conditions at depths of approximately 18 km. The extensional collapse is coeval with or shortly follows the main D2 collisional event in the Barberton greenstone belt at ca. 3230–3220 Ma. Voluminous plutonism at ca. 3225 Ma along the northern margin of the belt is possibly related to the orogenic collapse and associated decompression melting of lower crustal rocks. The extensional collapse coincides with the onset of the coarse-clastic Moodies Group sedimentation which suggests that the small, isolated Moodies basins formed as supradetachment basins in the collapsing hanging wall of the detachment. The steepening of lithologies and fabrics to their present-day vertical attitudes is ascribed to a late-stage solid-state diapiric component of the exhumed hot and buoyant basement gneisses that underlie the relatively cool and dense mafic and ultramafic supracrustal succession.

A new power electronic converter for switched reluctance motor

AbstractThis paper presents a new topology of bridge converter for a four‐phase switched reluctance motor (SRM). It consists of a four‐quadrant conventional bridge converter and extra switches for selecting phases of the motor. The converter is capable to control the phases of SRM properly and to operate similar compared to the conventional converter with different torques and speeds. There is a minimum number of passive elements and the rated voltage and current of solid‐state components are also minimum. This converter is very convenient for a four‐phase (in general even‐phases) SRM with high voltage and torque. Different modes of operation of SRM are analyzed using the proposed converter and simulation results for a typical 8/6 SRM are presented.

Microelectrochemical logic circuits.

We report microelectrochemical devices that mimic some functions of solid-state circuit components such as diodes and transistors. The operation of this new family of devices is enabled by a network of microfluidic electrochemical cells that communicate with one-another via conductive solutions and, in some cases, bipolar electrodes. The output of the devices can be either electrochemical or optical. The approach reported here is a first step toward the development of large-scale integrated electrochemical systems having parallel processing capabilities.

Continuous wave cavity ring-down spectroscopy applied to in situ detection of dinitrogen pentoxide (N2O5)

We describe an instrument using cavity ring-down spectroscopy (CRDS), an ultrasensitive detection method, to detect NO3 and N2O5 (via thermal dissociation to NO3 at 80 °C). We use continuous-wave (cw) cavity ring-down spectroscopy, allowing a highly reliable diode laser to act as the light source. This instrument uses all solid-state laser and optical components, and it is compact, portable, and power efficient. Advantages and disadvantages of cw CRDS compared to pulsed CRDS are discussed. Inlet losses and possible interferences were extensively investigated. We show field observations of N2O5 mixing ratios in ambient air. Dinitrogen pentoxide was measured because low ambient temperatures shift the equilibrium between NO3, NO2, and N2O5 strongly towards N2O5. Therefore, only N2O5 is assumed to be present in significant quantities in Fairbanks, AK, during winter. From these data, we identify times where the N2O5 mixing ratio must be zero (due to the absence of ozone indicating presence of NO) and use these time periods to measure the system’s operational detection limit. The 2σ detection limit for N2O5 is 2.4 parts per trillion by volume (pptv) in a 25 s average. Prediction of the N2O5 detection limit from estimates of ring-down signal noise indicates a detection limit of 1.6 pptv, in the same averaging period. The observed detection limit is about 50% larger than the predicted detection limit, indicating that other noise sources affect the true detection limit. A similar instrument using pulsed CRDS was described in the last year, and we compare our instrument to this instrument for detection of N2O5.