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Motivated by the recent successful synthesis of the layered platinum mineral jacutingaite (Pt2HgSe3), we have studied the optoelectronic, mechanical, and thermoelectric properties of graphene hetero-multilayer on Pt2HgSe3 monolayer (PHS) heterostructures (LG/PHS) by using first-principles calculations. PHS is a topological insulator with a band gap of about 160 meV with fully relativistic calculations; when graphene layers are stacked on PHS, a narrow band gap of ∼10–15 meV opens. In the presence of gate-voltage and out-of plane strain, i.e. pressure, the electronic properties are modified; the Dirac-cone of graphene can be shifted upwards (downward) to a lower (higher) binding energy. The absorption spectrum shows two peaks, which are located around 216 nm (5.74 eV) and protracted to 490 nm (2.53 eV), indicating that PHS could absorb more visible light. Increasing the number of graphene layers on PHS has a positive impact on the UV-vis light absorption and gives a clear red-shift with enhanced absorption intensity. To investigate the electronic performance of the heterostructure, the electrical conductance and thermopower of a device composed of graphene layers and PHS is examined by a combination of DFT and Green function formalism. The number of graphene layers can significantly tune the thermopower and electrical conductance. This analysis reveals that the heterostructures not only significantly affect the electronic properties, but they can also be used as an efficient way to modulate the optic and thermoelectric properties.

The Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) is designed to accurately observe ultra-high-energy cosmic rays (UHECRs) and cosmic neutrinos from space with sensitivity over the full celestial sky. POEMMA will observe the extensive air showers (EASs) from UHECRs and UHE neutrinos above 20 EeV via air fluorescence. Additionally, POEMMA will observe the Cherenkov signal from upward-moving EASs induced by Earth-interacting tau neutrinos above 20 PeV. The POEMMA spacecraft are designed to quickly re-orientate to follow up transient neutrino sources and obtain unparalleled neutrino flux sensitivity. Developed as a NASA Astrophysics Probe-class mission, POEMMA consists of two identical satellites flying in loose formation in 525 km altitude orbits. Each POEMMA instrument incorporates a wide field-of-view (45$^\circ$) Schmidt telescope with over 6 m$^2$ of collecting area. The hybrid focal surface of each telescope includes a fast (1~$\mu$s) near-ultraviolet camera for EAS fluorescence observations and an ultrafast (10~ns) optical camera for Cherenkov EAS observations. In a 5-year mission, POEMMA will provide measurements that open new multi-messenger windows onto the most energetic events in the universe, enabling the study of new astrophysics and particle physics at these otherwise inaccessible energies., Comment: 66 pages, 53 figures; JCAP accepted version

A combination of EGR and variation of injection rate has been used to keep both NOx and soot emissions at an acceptable level. To do so, a two-dimensional multi-zone phenomenological diesel engine combustion model has been developed. The model consists of several sub-models for spray development, fuel atomization, evaporation, combustion, and emission formation. The fuel spray is divided into several small packets called zones, and consequently, the equations for conservation of mass and energy are solved for each individual zone at each time step, from which the cylinder temperature and pressure are calculated. Additionally, the formation of emissions is tracked as soon as the combustion starts. Moreover, parallel processing programming techniques have been utilized, which reduce the computational time of the model considerably, making it a fast and reliable tool for combustion simulation. Using the model, different rates of EGR are applied, which as expected shows a noticeable decrease in NOx emissions. Thanks to the modular design of the model, injection profile can be changed easily. Instead of using a constant rate injection, three different injection patterns are used. First, an upward step profile is used, in which fuel is initially injected with a lower and then with a higher rate. After that, a downward step profile was applied, which injects the fuel first with a lower and then a higher rate. Finally, a combination of the above profiles is used, i.e., the fuel is injected initially at a low rate, and then, the injection rate is increased, and finally decreased again. It is shown that use of EGR with a combined injection pattern at the same time can keep the NOx and soot emissions of the diesel engine at an acceptable level.

Athletes used a lot of dietary supplements to achieve the more muscle mass and improve their athletic performance. The objective of this study was to investigate the effect of l-arginine supplementation on sport performance and body composition in male soccer players. This double-blinded, randomized and placebo-controlled trial was conducted on 56 male soccer players, with age range of 16–35, who referred to sport clubs in Isfahan, Iran. Subjects were randomly assigned to either l-arginine or placebo groups. Athletes received daily either 2 g per day l-arginine supplement or the same amount of placebo (maltodextrin) for 45 days. Sport performance and also body mass index (BMI), body fat mass (BFM) and lean body mass (LBM) were measured at the beginning and end of the study. Also, 3-day dietary records were collected at three different time points (before, in the middle of, and at the end of the study). The mean age of subjects was 20.85±4.29 years. Sport performance (VO2 max) significantly increased in l-arginine supplementation group (4.12±6.07) compared with placebo group (1.23±3.36) (P=0.03). This increase remained significant even after adjustment of baseline values, physical activity and usual dietary intake of subjects throughout the study. No significant effect of l-arginine supplementation was found on weight, BMI, BFM and LBM. l-arginine supplementation (2 g per day) could increase the sport performance in male athletes, but had no effect on anthropometric measurements, including BMI, BFM and LBM. So, further studies are needed to shed light our findings.

Using a three-dimensional numerical simulation, the dependencies of the electron cloud (virtual cathode) on the distance between the coils in the Polywell fusion reactor were examined. In the Polywell, the role of a stable and energetic virtual cathode is crucial for fusion. It is shown that by increasing the spacing coils, the electron confinement time increases initially and then remains constant. Using the simulation results, an optimum range for the spacing of coils was suggested, which leads to a longer and more effective confinement. The results obtained can be used to design future devices in order to have a more effective virtual cathode.

The phase relations in the 1.5GeS 2 + Cu 2 GeSe 3 ↔ 1.5GeSe 2 + Cu 2 GeS 3 system have been investigated over the entire concentration range mainly by thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, with the aid of microhardness and electro-motive force measurements (EMF) applied to equilibrated alloys. The liquidus surface projection, isothermal section at 800 K and the phase diagrams of the two vertical sections have been constructed. The homogeneity ranges and primary crystallization fields of phases as well as the character and temperature of non- and monovariant equilibria were determined in the system. It was found that the system is reciprocally reversible and is featured by continuous solid solubility fields along the boundary GeS 2 –GeSe 2 and Cu 2 GeS 3 –Cu 2 GeSе 3 systems. The partial molar thermodynamic functions ( Δ G ‾ , Δ H ‾ , Δ S ‾ ) of copper were calculated for the Cu 2 GeS 3 − x Se x (for x = 0.6; 1.2; 1.8; 2.4) solid solutions based on the results of the EMF measurements.

The aim of this study is to investigate the photoelectrochemical (PEC) water splitting properties of α-Fe2O3 /reduced graphene oxide nanocomposite (α-Fe2O3/rGO) and the significance of annealing temperature on the photoelectrochemical performance. The α-Fe2O3/rGO nanocomposite deposited on FTO substrate, using electrochemical deposition and annealed in atmospheric N2 at 300, 500 and 700 °C. The synthesized nanocomposites were characterized by raman spectroscopy, X-ray photoelectron spectroscopy, and field emission scanning electron microscopy. The α-Fe2O3/rGO nanocomposites were used as photoanode materials in the PEC water splitting process. The results shows the reduced graphene oxide acts as an electron acceptor leading to an increase of availability of photo-generated electrons and hence higher PEC performance of α-Fe2O3/rGO nanocomposites compared to pure α-Fe2O3. The photoanode annealed at 700 °C shows the highest PEC performance.

The Tl 2 Te–TlBr–TlI system was investigated by means of the DTA and XRD analyses and microhardness and EMF measurements. Several polythermal and isothermal sections and the projection of the liquidus surface were constructed. The fields of primary crystallization, as well as types and coordinates of non- and monovariant equilibriums were determined. It was established that the system is characterized by formation of the continuous solid solution (γ-phase) between the Tl 5 Te 2 Br and Tl 5 Te 2 I (Tl 5 Te 3 structure type) iso-structural compounds. The homogeneity field of γ-phase in the Tl 5 Te 2 Br–Tl 5 Te 2 I section penetrates the Tl 2 Te–Tl 5 Te 2 Br–Tl 5 Te 2 I subsystem and occupies its large part. The partial molar thermodynamic functions ( Δ G ¯ , Δ H ¯ , Δ S ¯ ) of thallium were calculated for the Tl 5 Te 2 Br x I 1− x (for x = 0.2; 0.4; 0.6; 0.8) solid solution based on the results of the EMF measurements.

Thermoelectric properties of a carbon nanotube quantum dot such as electrical conductance, thermal conductance, thermopower, and figure of merit are analyzed. Influence of electron–electron, spin–orbit, and electron–phonon (EPI) interactions on the thermoelectric properties of system is taken into account using the Green function formalism in the linear response regime. It is observed that the temperature difference between electron and phonon subsystems results in the fluctuation of the thermopower and enhancement of the figure of merit. It is also found that the figure of merit is reduced in high temperatures due to the bipolar effect induced by the EPI resulting in the reduction of electrical conductance and increase of thermal conductance.

The present study describes an electrocoagulation process for the removal of remazol yellow G from dye solutions using Iron as the anode and Steel as the cathode. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to analyze the kinetic data obtained at different concentrations in different conditions. The adsorption kinetics was well described by the pseudo-second-order kinetic model.

Explosive welding was used to produce scarf joint between aluminum and copper plates. This process is known as explosive scarf welding (ESW). In a scarf joint, the final bond interface is oblique. In this study, chamfered end of aluminum and copper plates were joined explosively and named scarf joint, employing changes in chamfered angle at different stand-off distance and explosive loading. The geometry of scarf joint enables consideration of both flyer and base plate thickness and explosive loading and the effects on mechanical properties of interface such as bond shear strength and micro-hardness can be investigated. Mathematical models developed on the interface properties of scarf joint to make relationship between the bond shear strength and explosive loading ratio. To check the adequacy of developed models, mechanical properties of interface, such as bond shear strength was predicted and compared with actual values in explosive cladding process. The results show reasonable agreement with theoretical predictions. Consequently, mathematical model which is based on scarf joints, can predict bond shear strength of cladding metals under desired explosive loading and flyer plate thickness.

Microcavity laser linewidth behavior close to the threshold transition region is investigated through high-resolution linewidth measurements. A local maximum is found for the linewidth of lasers operating slightly above threshold. The increase in laser linewidth close to threshold is explained by the effective contribution of the linewidth enhancement factor (alpha) to the laser linewidth. The Fokker-Planck model of laser noise is then solved using the eigenfunction expansion method to fit to the measured linewidth data. The behavior of the measured linewidth agrees with the model with an extracted linewidth enhancement factor (alpha) ranging between 3.5 and 5.0.

We report on our progress made in developing microcavity photonic crystal lasers. Both suspended membrane devices and devices formed in membranes bonded to sapphire are described.

Cytokine gene polymorphisms may affect their transcription, influence their level of production and may be implicated in inducing susceptibility or resistance to diseases. In 40 Iranian healthy subjects, cytokine single-nucleotide polymorphisms (SNPs) were used to determine allelic and genotypic frequencies for the following cytokine genes: IL-1a (T/C -889), IL-1beta (C/T -511, T/C 3962), IL-12 (C/A -1188), IFN-gamma (A/T UTR 5644), TGF-beta (C/T codon 10, G/C codon 25), TNF-a (G/A -308, G/A -238), IL-2 (T/G -330, G/T 166), IL-4 (T/G -1089, T/C -590, T/C -33), IL-6 (G/C -174, G/A nt565), IL-10 (G/A -1082, C/T -819, C/A -592), IL-1R (C/T pst11970), IL-1RA (T/C mspa111100) and IL-4RA (G/A 1902). All typing were performed with polymerase chain reaction with sequence specific primers assay. Significant heterogeneity of cytokine SNPs among the Iranian and the other East-South Asian populations was observed. Heterogeneity of cytokine SNPs may explain the role of natural selection in susceptibilities of populations to different disorders.

Thermal and electron transport through organic molecules attached to three-dimensional gold electrodes in two different configurations, namely para and meta with thiol-terminated junctions is studied theoretically in the linear response regime using Green's function formalism. We used thiol-terminated (–SH bond) benzene units and found a positive thermopower because the highest occupied molecular orbital (HOMO) is near the Fermi energy level. We investigated the influence of molecular length and molecular junction geometry on the thermoelectric properties. Our results show that the thermoelectric properties are highly sensitive to the coupling geometry and the molecular length. In addition, we observed that the interference effects and increasing molecular length can increase the thermoelectric efficiency of device in a specific configuration.

Gain compression factor and thermal properties of a photonic crystal microcavity laser bonded on a sapphire substrate are extracted by analyzing wavelength shifts under different duty cycles. A high thermal resistance of 43 K/mW and a gain compression factor of 1.2 times 10-16 cm3 are obtained.

Linewidth and small-signal modulation response measurements are reported for room-temperature-operating microcavity two-dimensional photonic crystal lasers. The measured optical linewidth versus the output power was found to saturate at values on the order of 1 GHz. The modulation bandwidth for these low-power lasers was demonstrated to be on the order of 10 GHz

Sapphire-bonded photonic crystal laser cavities with varying number of photonic crystal periods were studied in order to determine the optical loss in these cavities. The lasing threshold increases as the number of lattice periods decreases, and the quality factors of these cavities were calculated from the lasing threshold data. Continuous-wave operation was achieved for cavities with eight or more cladding periods

Room-temperature continuous-wave lasing was demonstrated in photonic crystal microcavities with diameters of approximately 3.2 /spl mu/m. Far-field radiation patterns of these lasers were experimentally measured and compared with numerical simulation predictions.

In this paper, we investigate the impact of longitudinal dispersion fluctuations of the optical fiber on the gain spectrum and the saturation behavior of one-pump fiber-optical parametric amplifiers (1-P FOPAs). The gain spectra and the saturation curves of 1-P FOPAs are simulated by solving the coupled amplitude equations numerically and taking into account the dispersion fluctuations as a stochastic process with a given standard deviation and correlation length. Results show that the shape and the level of the gain spectrum and also the saturation power of 1-P FOPAs are considerably changed in the presence of dispersion fluctuations in comparison with the case when dispersion fluctuations are ignored. This feature is also totally different compared with the small-signal gain spectrum of the FOPA in the presence of dispersion fluctuations. Moreover, the value of the change in the gain and the saturation power depends strongly on the fluctuation parameters, i.e., the standard deviation and the correlation length.

The authors present an 11.6-GHz 1:4 regenerating demultiplexer (demux) and a 6.1-GHz phase aligner, implemented using high-current-gain baseline AlGaAs/GaAs heterojunction bipolar transistor (HBT) technology. The demux features a hybrid tree/shift register-type architecture optimized for high-speed and low-power operation, and is the fastest demux with bit-rotation control ever reported. It consumes 1.4 W of power with a single -5 V supply, and has a phase margin of 270 degrees and differential input data sensitivity of 56 mV/sub p-p/ at 11.6 Gb/s. The phase aligner incorporates an auto-latching scheme which allows the data to be latched using a timing signal derived on-chip from the data, and is the fastest fully monolithic phase aligner ever reported. It dissipates 0.8 W of power with a single -5 V supply and has differential input data sensitivity of 60 mV/sub p-p/ at 6.1 Gb/s. >

Two-dimensional photonic crystal defect lasers in InGaAsP membranes directly bonded to a SiO(2)/Si substrate have been demonstrated. Lasing at wavelengths near 1550 nm was obtained with incident threshold pump powers as low as 1.5 mW. Good agreement between experimental data and three-dimensional finite-difference time-domain (FDTD) simulation was achieved. The thermal impedance of this laser is also characterized.

Gain compression factor and thermal properties of a sapphire-bonded microcavity laser are extracted by analyzing wavelength shifts under different duty cycles. High thermal resistance of 21K/mW and gain compression factor of 1.0µ10−16cm−3 are obtained.

The authors discuss several important circuits for fiber-optic transmission, implemented in an advanced silicon bipolar integrated circuit technology. Specifically, the authors discuss the design considerations and measured performance of a 2:1 multiplexer, front end receiver, limiting amplifier, and decision circuit IC. Also discussed are three hybrid circuit modules: a 2:1 multiplexer, 1:2 demultiplexer, and parallel processing decision circuit. These ICs and hybrid circuit modules operate at multi-Gb/s data rates. The performance of these ICs indicates that advanced silicon bipolar integrated circuits with their high speed, functionality and low cost potential could play an important role in alleviating the electronic bottleneck in future multigigabit optical communication systems. >

The effect of the carrier capture into quantum wells on the modulation response of semiconductor laser is investigated. It is shown that the capture limits the maximum possible modulation speed by increasing gain nonlinearities.

In order to reduce the optical absorption loss, an array of double-heterostructure photonic crystal microcavity lasers was fabricated in which much of the photonic crystal mirror region was disordered by quantum well intermixing. In characterizing these devices, we obtained more than a factor of two increase in slope efficiencies and more than 20% reduction in threshold pump powers compared to devices that were not intermixed.

In this report, microdisk lasers with -3dB small-signal modulation bandwidths in excess of 17 GHz are demonstrated. Linewidth of these lasers are also measured and a minimum linewidth of 85 MHz is achieved.

An array of double-heterostructure photonic crystal QW membrane lasers was fabricated in which number of cladding periods was varied. 60 muW peak output power was collected from the facet of one device by a bare fiber.

We describe the demonstration of sapphire-bonded photonic crystal lasers operating under room temperature CW conditions and characterize the modal properties and small-signal modulation response of these lasers. In addition, we describe progress in photonic crystal nanocavity lasers which have InAs QD active material, and investigate the optical properties of passive photonic crystal waveguide components.)

Sapphire-bonded photonic crystal lasers were fabricated and characterized under room temperature continuous wave operation, and a side-mode-suppression-ratio of 28 dB was observed. Lasing modes and spectra agree with theoretical prediction from three-dimensional finite-difference time-domain method.

Device characteristics of photonic crystal lasers formed in InGaAsP membranes bonded to a sapphire substrate are discussed. Also discussed are waveguide loss mechanisms in type-A and type-B photonic crystal waveguides and the transmission properties of photonic crystal waveguide bends.

High-Q photonic crystal heterostructure laser cavities were fabricated and characterized. Good agreement was obtained between the numerical predictions and the experimental lasing data.

Non-zero coupling coefficients between the pseudo-orthogonal modes of waveguides and microdisks lead to the possibility of preferential polarization mode conversion in these devices. Active microdisks have been demonstrated as polarization rotators based on this property.

The linewidth of 2-D photonic crystal microcavity lasers was measured using the self delayed optical homodyne technique.

The diluted essential oil of Mentha longifolia (L.) var. chlorodictya Rech F. foliage enhanced the bactericidal activity of nitrofurantoin decreasing the minimum inhibitory concentration (MIC) of nitrofurantoin for nitrofurantoin-resistant strains of Enterobacteriaceae. Thin-layer chromatography (TLC) analysis of the essential oil detected a fraction (R(f) = 0.35, UV lambda(max) of 232.5), which was the most effective in enhancement of nitrofurantoin activity. Using gas liquid chromatography and known standards, the active fraction was identified as piperitone. 1 microl of the piperitone fraction decreased the MIC of nitrofurantoin 3-20 fold for the different strains of Enterobacteriaceae tested.

The authors discuss a 2:1 multiplexer operating from 100 Mb/s to 11.4 Gb/s, which was fabricated using a silicon nitride self-aligned process that features 0.6- mu m-wide arsenic-doped emitters with 4- mu m base-to-base pitch, deep trench isolation, 2- mu m-thick field oxide isolation, polysilicon resistors, and a two-layer TiW-Au metallization. This technology produces transistors with a cutoff frequency (f/sub t/) of 10-15 GHz. The chip measures 0.9*0.8 mm/sup 2/, dissipates 350 mW with a 5-V supply, and operates at the fastest data rate reported to date for a multiplexer in any IC technology. >

A 1:4 demultiplexer is reported which includes the following features: (1) output data unstaggered in time; (2) input clock with frequency equal to the input data bit rate; (3) bit pattern alignment capability; and (4) only the phases of input data and input clock aligned externally. The device uses a simple bit alignment scheme requiring only one external control signal. The demux and phase aligner use AlGaAs/GaAs HBT (heterojunction bipolar transistor) technology featuring emitter-up/single-heterojunction bipolar transistors, monolithically integrated Schottky diodes, NiCr thin-film resistors, MIM capacitors, and up to three levels of metal interconnect. >

Small-signal gain spectrum of one-pump fiber optical parametric amplifiers (1-P FOPAs) is investigated in the presence of dispersion fluctuations. By assuming the dispersion fluctuations along the fiber as a stochastic process and using the matrix approach, the full gain spectrum of 1-P FOPAs is simulated. We have examined the gain spectrum of 1-P FOPAs for a wide range of fluctuation parameters, and it is shown for the first time that there are two specific wavelengths at which the dispersion fluctuations play no role. Analytical formulas are also presented to design 1-P FOPAs for amplifying signals with a gain insensitive to dispersion fluctuations.

Background: Usually the chest tube removal (CTR) has been described as one of the worst experiences by patients in the intensive care unit. Aim: This study aimed to compare the effects of cold therapy and relaxation on pain of CTR among the patients undergoes coronary artery bypass graft surgery. Materials and Methods: This single-blinded clinical trial was done on 80 post-cardiac surgery patients in the heart hospital of Sari-Iran. The patients were assigned to three randomized groups that included cold therapy, relaxation, and control groups. Data analysis was done by T-test, Chi-square, generalized estimating equations and repeated measures analysis variance tests. Results: The groups had no significant differences in pain intensity before CTR (P = 0.84), but immediately after CTR there was a significant difference between the treatment (cold application and relaxation groups) and control groups (P = 0.001). There was no significant difference between relaxation and cold therapy groups. Conclusion: Regarding the relaxation and cold application methods showed relatively equal effects on reducing the pain owing to CTR. Thus, the use of relaxation because of economics, without side effects, easy to use and effective is recommended by the authors to the practitioners.

As an attempt to collect more in-plane emission power out of wavelength size two-dimensional photonic crystal defect lasers, edge-emitting photonic crystal double-heterostructure quantum well membrane lasers were fabricated by shortening the number of cladding periods on one side. 120μW peak output power was collected from the facet of the single mode laser at room temperature. Laser efficiencies were analyzed and agree very well with three-dimensional finite-difference time-domain modeling.

Sapphire-bonded photonic crystal laser cavities were fabricated and characterized under room temperature continuous-wave operation, and the single mode lasing with a side-mode-suppression ratio of 28dB was observed. The lasing modes of the photonic crystal cavities were characterized and compared to calculated spectra from the three-dimensional finite-difference time-domain method.

A high-quality-factor (Q) photonic crystal heterostructure laser was designed and characterized. Good agreement was obtained between the experimental lasing data and three-dimensional finite-difference time-domain numerical predictions.

Two hybrid circuit modules, an 11 Gbit/s 1:2 demultiplexer and a 12 Gbit/s 2:1 multiplexer, are described. The modules use silicon bipolar integrated circuits and feature multiple input/output connectors, excellent insertion and return losses, and flat group delays.

The design and implementation of a submicron-silicon bipolar parallel processing master-slave D-type flip-flop decision circuit, operating at data rates as high as 11 Gbit/s is described. This is the fastest reported decision circuit for silicon bipolar technology. The ICs used in the hybrid circuit were fabricated using a 0.6 μm, non-polysilicon emitter technology, and mounted in a package employing coplanar waveguides.

High performance 0.5 mu m gate length InGaAs/GaAs pseudo-MODFETs are demonstrated on InP substrates by MOVPE heteroepitaxial growth. The transistors show a 300 mS/mm transconductance and a 30 GHz cutoff frequency. A 2:1 multiplexer is also made using the same technology. Preliminary testing indicates that the multiplexer can operate up to 10 Gbit/s. >

This paper presents a four-terminal small-signal dc-to-high-frequency model, valid in weak, moderate, and strong inversion regimes, for the intrinsic part of the long-channel MOS transistor. A charge-sheet approximation is used. Basic MOSFET equations are separated into parts corresponding to dc and ac small-signal components. The former are used to evaluate the drain current under dc conditions; the latter, describing the "transmission-line" behavior of the MOSFET, are solved to arrive at a complete set of admittance parameters. Based on different approximations of these parameters, various models are presented, each of different upper frequency limit of validity. For each model parameter, a single continuous expression is used which is valid in all regions of operation (weak inversion, moderate inversion, strong inversion; nonsaturation and saturation). The frequency range of validity of these models and the inadequacies of the quasistatic models at high frequencies are discussed. It is shown that at low frequencies the high-frequency model reduces to a quasistatic model which is widely verified by experimental results; at high frequencies the model agrees with available measurements.

This paper presents a four-terminal small-signal high-frequency model, valid in weak moderate and strong inversion regimes, for the intrinsic part of the long-channel MOS transistor. Small-signal partial differential equations describing the "transmission-line" behavior of the MOSFET are derived and solved to arrive at a complete set of admittance parameters. Based on different approximations of these parameters various models are presented, each of different upper frequency limit of validity. By discussion the frequency range of validity of these models, the inadeqacies of the quasi-static models at high-frequencies are highlighted.

An increase in the spectral width of microdisk laser spectra biased slightly above threshold is experimentally observed, and an increase in spontaneous emission rate in devices with small optical mode volume is demonstrated.

Explicit expressions are derived for the drift and diffusion components of the channel current as a function of position along the channel of a MOSFET. It is shown that in moderate inversion the assumption that the channel current is ‘mostly due to diffusion’ or ‘mostly due to drift’ can lead to not only quantitative but also qualitative errors, since drift and diffusion can dominate simultaneously, but at different parts of the channel.