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The lead-free ceramics (1 − x)(0.94 Bi 0. 4 7 Na 0. 4 7 Ba 0. 0 6 TiO3-0.06BiAlO3)- x AgNbO3 (denoted as BNBTA- x AN) were synthesized via a solid-state sintering method. The effect of AgNbO3 doping amount on dielectric properties of the ceramics was studied systematically. X-ray diffraction (XRD), scanning electron microscope (SEM) and Raman spectroscope were used to detect the structure of the ceramics. Temperature-dependent dielectric spectra, frequency-dependent dielectric constant and alternating current (ac) electric conductance at various temperatures were measured. The doping of AgNbO3 greatly reduces dielectric constant around Curie temperature and thus enhances the temperature stability of the dielectric constant. The ceramic BNBTA-0.03AN exhibits excellent temperature-stable dielectric properties with temperature coefficient of capacitance (TCC) ≤ ± 15% between 55∘C and 418∘C with temperature window 363∘C and small changes of dielectric constant and dielectric loss from 100 Hz to 1 MHz at different temperatures. The obtained ceramics are expected to be used in high-temperature capacitors due to its excellent temperature stability. [ABSTRACT FROM AUTHOR]

More and more, established companies try to cooperate with start-ups, build their own, or try to imitate their mindsets. But, do they make decisions like expert entrepreneurs? Effectuation theory describes entrepreneurial decision-making, it has been popular in entrepreneurship research for the last two decades, but still underexplored in contexts such as established company's decision-making. Therefore, this study answers the question of which factors affect the use of effectuation in established companies. Furthermore, the current use of the start-up decision-making principle is investigated. The research results show a higher use of effectuation over causation (alternative mechanism) in established companies. However, decision-making principles like "Mean orientation" and "Contingency orientation" are still dominated by causation. Identified factors for implementing effectuation in established companies are divided into six categories. In particular, effectuation requires a high flexibility and willingness to change goals. Using the already available means and resources of a company to pursue new goals, is another argument for using effectuation. Additionally, a more open and transparent culture, encouraging the identification and admittance of mistakes, also supports the use of effectuation. Based on this research, established companies should be able to understand better on which factors the implementation of effectuation depends and where it makes sense to use it. [ABSTRACT FROM AUTHOR]

This paper presents a supper class-AB adaptive biasing bulk-driven amplifier for ultra-low-power applications. In the proposed structure, two bulk-driven flipped voltage follower (FVF) cells are reconfigured as nonlinear tail currents using quasi-floating gate method to enhance transconductance and slew rate. In addition, two idle current controllers are employed as common source amplifiers to provide a supper class-AB structure without increasing total current consumption. The proposed structure is simulated in 0.18-m CMOS technology at 0.5V supply with 35nW power budget. The results show a 57.9dB DC gain, 8.8kHz gain bandwidth and 38.2V/ms slew rate for the proposed amplifier. [ABSTRACT FROM AUTHOR]

We found that quantization of the scanning tunneling microscope (STM) current becomes apparent as the size of a quantum corral (QC) decreases and the corral thickness increases. It is shown that STM current images provide the position dependence of the conduction channels and local density of states (LDOS) images provide the spatial distribution of differential conductance channels. We clarified for the first time that there exist fractal structures in the QC size dependence of the - characteristic and in that of the LDOS. LDOS images also exhibit a fractal structure as a function of bias voltage. These results demonstrate fractal structures in energy space and real space. For an extremely large QC, we found that the - curve becomes Ohmic and the LDOS converges to a constant corresponding to the bulk two-dimensional density of states. [ABSTRACT FROM AUTHOR]

The effect of iron atom junction on transport characteristics of carbon-silicon mixed chain has been studied from an ab initio study. At zero bias, the Fe(CSi) system appears to be the decrease of the conductance as the number of the Si-C pairs in the chain increases ( n changes). When n 5, the conductance tends to zero. These changes are independent of the transferring charge of the system, depending on the coupling of the electrodes and the central region. Under bias, the higher the bias voltage, the bigger the transmission coefficient of the system, and the transmission peak moves closer to the Fermi level. The I- V curves of Fe(CSi)2 and Fe (CSi)3 are linear, showing the behavior of metal resistance. [ABSTRACT FROM AUTHOR]

In this paper, we present the effect of process parameters variations on - characteristics of LDD MOSFETs through a simulation study, applying also to any submicron device. In particular, we examine the effect of variation of ionic implantation for different channel doping involved in MOSFET production. At last, we examine a linear - model to simulate more adequately the effects of variation of the process parameters as correction to the base model. [ABSTRACT FROM AUTHOR]

Most existing stand-alone photovoltaic (PV) power systems employ pulse-width-modulated (PWM) DC-DC converters for maximum power point tracking (MPPT) and battery charging control. However, PWM converters experience high switching loss and high electromagnetic interference when operating at high frequency. Therefore, this paper presents an incremental conductance (INC)-based MPPT with constant voltage (CV) charging using LLC resonant converter for stand-alone solar streetlight system. INC MPPT maximizes the PV power generation while CV charging ensures good battery charging characteristics. Both the INC MPPT and CV charging are implemented in an algorithm using an Arduino Uno board. Detailed design procedure as well as extensive design considerations for a 100W prototype LLC resonant converter are presented. Experimental results show good MPPT performance under various environmental conditions such as sudden rise or sudden drop of incident irradiance. Furthermore, the system shows exceptional robustness in toggling between INC MPPT mode and CV charging mode depending on the environmental conditions. The converter displays excellent switching operation by achieving primary-side zero voltage switching and secondary-side zero current switching for the entire design range. [ABSTRACT FROM AUTHOR]

Graphene quantum dots (GQDs) are considered as fascinating materials feasible for biological, optoelectronic devices, energy and environmental applications. Casting nanocomposite films for technological application is a challenging research interest. Cellulose acetate (CA) is one of the most abundant, economic, environmental friendly and biodegradable biomaterials. It has been found that CA is a preferred composite matrix to prepare recasting films, due to its efficient antifouling feature. In the present investigation, we exhibited preparation of CA/GQD nanocomposite by solution blending as a function of GQD loading 0.1-0.5wt.%. Morphology and electrical properties were examined as a function of GQD loading. The nanocomposite was characterized by impedance spectroscopy, and the measured admittance () was plotted against temperature across broadband frequency. The magnitude of exhibits direct relation under the varying temperature. The morphology of the nanocomposites was observed by atomic force microscope technique in contact mode. Collective observation from our results is that it can be revealed that CA/GQD nanocomposites are suitable for thermal sensing applications. [ABSTRACT FROM AUTHOR]

The control of ionic transportation inside the multi asymmetric conical nanopores in polyethylene terephthalate (PET) membrane was investigated. The conical nanopores were prepared by chemical etching in irradiated PET foil using etchant (9 M NaOH) and stopping solution (1 M NaCl 1 M HCOOH). The behavior of ionic current was recorded under stepping voltage 2V to 2V at different molar concentrations of potassium halides (KCl, KBr and KI) under symmetric bathing condition in electrochemical cell. It is found that the presence of multiple ionic species and the occurrence of counterion condensation of charge regulated polyelectrolyte play an effective role in ionic current rectification (ICR). The electrical conductance of conical nanopores may be estimated by measuring the ionic current rectification properties of track-etched nanopores. The charge transport properties vary with molar concentration and pH of electrolyte. Moreover, ICR may be used as a voltage gating phenomena with wide technological applications. Ionic transportation inside multi-asymmetric conical nanopores in polyethylene terephthalate membrane was observed. Conical nanopores were prepared by chemical etching using etchant (9M NaOH) and stopping solution (1M NaCl + 1M HCOOH). Transport behavior of ionic current was recorded at different molar concentrations and pH of potassium halides. It is found that the transport properties of conical nanopores vary with molar concentration and pH of electrolyte. Ionic current rectification may be used as a voltage gating phenomena with wide technological applications. [ABSTRACT FROM AUTHOR]

An amorphous indium-gallium-zinc-oxide ( a-IGZO) thin-film transistor (TFT) with a planar split dual gate (PSDG) structure has been proposed, fabricated and characterized. Experimental results indicate that the two independent gates can provide dynamical control of device characteristics such as threshold voltage, sub-threshold swing, off-state current and saturation current. The transconductance extracted from the output characteristics of the device increases from to for a change of control gate voltage from −2 V to 2 V, and thus the device could be used in a variable-gain amplifier. A significant advantage of the PSDG structure is its flexibility in controlling the device performance according to the need of practical applications. [ABSTRACT FROM AUTHOR]

We present a theoretical method based on Green's function technique and tight-binding approach as well as harmonic approximation in order to calculate the coherent electronic conductance of an extended poly(p-phenylene) oligomer in the presence of thermal atomic vibrations. We study two proposed mass-spring models for atomic vibrations: one, including rigid benzene rings connected to each other by vibrating bonds; and in another, the bonds along the oligomer vibrate even in the benzene rings. The electron-phonon (e-ph) interaction influences the electron hopping energies linearly with respect to atomic displacements. The model shows that the conductance spectra exhibit some new energy gaps in the presence of e-ph interaction even at zero temperature. The conductance is more affected by e-ph interaction when the atomic vibrations are supposed to be present in the benzene rings. At the edges of the band energy and central gap, the phonon-assisted phenomena can be observed. Generally, the increasing e-ph interaction strength as well as temperature destroys the electronic conductance especially in the resonance region. [ABSTRACT FROM AUTHOR]

In this paper, we consider a single cell model of pre-Bötzinger complex, which is derived by adding an external tonic drive () to the model developed by Park and Rubin. Using fast-slow geometric decomposition and bifurcation analysis, we study firing activities of the system and try to reveal the mechanisms underlying the bursts related to the mean level of excitatory input () and the maximal conductance associated with the sodium (). Since a regular bursting requires at least two timescales, we consider the effects of timescale, especially of the slow timescale, on the bursting oscillations. Unlike the previous works, in this paper, we conduct our investigation by choosing different slow variables. We show how and affect bifurcations of the fast subsystem and how the bifurcations further determine firing activities of the full system with different slow variables. [ABSTRACT FROM AUTHOR]

In this paper, we present a new method increasing quality factor of active filter structure in the literature and a new designed filter. The new method is easily applied to all different filter modes with the proper feedback circuit. The center frequency of the filter remains constant as quality factor of filter increases. Also, quality factor can be also tuned electronically by changing the biasing current of the feedback circuit. Furthermore, the performance of the method is demonstrated by CMOS simulation of differential voltage current conveyor and transconductance amplifier. Quality factor value of the filter can also be easily adjusted electronically between 1 and 20 with the presented method. Finally, an application example of the presented method is presented for double tuned amplifier for intermediate frequency pre-amplifier of FM receiver. [ABSTRACT FROM AUTHOR]

This paper presents new programmable universal biquadratic filters using current conveyor transconductance amplifiers (CCTAs) by which both voltage- and current-mode filters can be obtained. The proposed filters use second-generation current conveyor (CCII) which is the first stage of CCTA to operate as current conveyor analog switch (CCAS) and this CCAS will be used to program the filtering functions such as low-pass, high-pass, band-pass, band-stop and all-pass filters. Unlike previous universal filters, the filtering functions of the proposed filters can be programmed using the bias currents of CCTAs without changing any input and output connections. The natural frequency and quality factor of all filtering functions can be controlled electronically and orthogonally using the bias currents of transconductance amplifiers. Also gain response of all transfer functions can be adjusted. The active and passive sensitivities of the filters are low. The proposed programmable filters have been simulated using 0.18m CMOS process from TSMC. PSPICE simulation results are included to confirm workability of the proposed circuits. [ABSTRACT FROM AUTHOR]

This paper presents a compact second-order bandpass filter developed by combining the well-known flipped voltage follower circuit as a transconductance network with two capacitors. Operated in the subthreshold region, the filter's center frequency can be adjusted linearly by varying the bias current. Post-layout simulation using a 0.35-m CMOS process confirms the suitability of the proposed filter in low-voltage, low-power environment. [ABSTRACT FROM AUTHOR]

Using numerical simulations, we investigate the effects of the connectivity and topologies of network on the quality of transport between connected scale free networks. Hence, the flow as the electrical conductance between connected networks is calculated. It is found that the conductance distribution between networks follow a power law where is the exponent of the global Network of network, we show that the transport in the symmetric growing preferential attachment connection is more efficient than the symmetric static preferential attachment connection. Furthermore, the differences of transport and networks communications properties in the different cases are discussed. [ABSTRACT FROM AUTHOR]

A quantum impurity system out of equilibrium comprises two metallic reservoirs with different chemical potentials and one mediating spin impurity between them. We study the highly nonlinear tunneling conductance of this system, and clarify that three coherent peaks, one zero-bias peak and two side peaks, naturally appear in the tunneling conductance. We use the Liouvillian approach, in which a complete set of basis operators is available, and construct a Liouville matrix to obtain Green's function at the mediating site. We show that the two coherent side peaks are the outcome of steady-state nonequilibrium combined with strong electron correlation at the mediating site. Tunneling in the quantum impurity system out of equilibrium is performed by an entangled state which is a linear combination of two Kondo singlets formed by the spin at the mediating site and the coherent spins in each reservoir. The fluctuation by incoherent spins is also included. The spectral weights and positions of the three coherent peaks are analytically discussed via atomic limit analysis. Our theoretical results well fit experimental data obtained for quantum point contacts with symmetric and asymmetric Kondo couplings. [ABSTRACT FROM AUTHOR]

An exactly solvable relativistic approach based on inseparable periodic well potentials is developed to obtain energy-dispersion relations of spin states of a single-electron in two-dimensional (2D) rectangular lattices. Commutation of axes transfer matrices is exploited to find energy dependencies of the wave vector components. From the trace of the lattice transfer matrix, energy-dispersion relations of conductance and valence states are obtained in transcendental form. Graphical solutions of relativistic and nonrelativistic transcendental energy-dispersion relations are plotted to compare how lattice parameters , core and interstitial size of the rectangular lattice affects to the energy-band structures in a situation core and interstitial diagonals are of equal slope. [ABSTRACT FROM AUTHOR]

Presented work deals with applications of the single -copy controlled-gain voltage differencing current conveyor (ZC-CG-VDCC) in single purpose and multifunctional biquadratic voltage- and current-mode active resistor-less filters. Electronically adjustable features of the active device (intrinsic current input resistance , current gain and transconductance ) are controlled by DC bias current. These mentioned adjustable features allow interesting possibilities of control of the pole frequency and quality factor. Four voltage-mode solutions realizing low-pass, band-pass, high-pass and band-reject filtering solutions were designed together with two current-mode filters. The current-mode solutions have curious multifunctional capability based on full utilization of electronically controllable parameters of the ZC-CG-VDCC. Two adjustable parameters of the ZC-CG-VDCC (intrinsic current input resistance and transconductance) are used for electronic setting of features of the filter (pole frequency, quality factor, tuning). Control of the third adjustable parameter (current gain) causes reconnection-less change of the transfer function between iAP (inverting all-pass response) and iBR (inverting band-reject responses). Simulation results in PSPICE and Cadence CDS 6 are used to show characteristics of the proposed circuits. [ABSTRACT FROM AUTHOR]

This paper presents a single-stage ultra-low-power fully differential operational transconductance amplifier (FD-OTA) with rail-to-rail linear input range operating in weak inversion region. The input core of the OTA is comprised of source degenerated, flipped voltage follower (FVF)-based bulk-driven class AB input pair, into which a regenerative feedback loop has been inserted to boost its bulk transconductance (). The proposed FD-OTA has utilized self-cascode current mirror (SC-CM) loads, which increase its open loop gain from nominal intrinsic value of 42dB to 70.4dB. It has provided 9.24kHz gain bandwidth (GBW), consuming 64nW of quiescent power from a 0.51V single power supply at 15pF load. The proposed OTA in unity gain configuration has ensured reduced total harmonic distortion (THD) of dB at 200Hz frequency and 1V signal swing. Its fully differential class AB input and output structures have ensured increased gain, GBW, slew rates and output swings with reduced nonlinearity and common mode substrate noise. The Cadence Virtuoso environment using GPDK 180nm standard -well CMOS process technology has been used to simulate the proposed circuit. [ABSTRACT FROM AUTHOR]

This paper presents the complementary metal oxide semiconductor (CMOS) implementation of active building block, namely, current inverting differential input transconductance amplifier (CIDITA) along with its performance parameters. The detailed study of the proposed CMOS CIDITA has been incorporated. The presented study shows the good performance of CIDITA in terms of good bandwidth range, good linear range of input current, high accuracy and low operating voltage. A new circuit of single active element-based quadrature oscillator is further realized to explore the workability of CIDITA. The proposed circuit of quadrature oscillator employs two grounded capacitors, one resistor and single CIDITA. The proposed quadrature oscillator provides both quadrature current outputs and quadrature voltage outputs simultaneously. The frequency of oscillation of the proposed quadrature oscillator is electronically controllable. The possible practical realization of the CIDITA using commercially available ICs is also given. HSPICE simulation results using 0.18m CMOS parameters are given to validate the proposed theory. [ABSTRACT FROM AUTHOR]

In this paper, the interface charge densities () are studied and analyzed for ultra thin dielectric metal oxide semiconductor (MOS) devices using different high- k dielectric materials such as Al2O3, ZrO2 and HfO2. The have been calculated by a new approach using conductance method and it indicates that by reducing the thickness of the oxide, the increases and similar increase is also found by replacing SiO2 with high- k. For the same oxide thickness, SiO2 has the lowest and found to be the order of 10cmeV. Linear increase in has been observed as the dielectric constant of the oxide increases. The is found to be in good agreement with published fabrication results at p-type doping level of cm. Numerical calculations and solutions are performed by MATLAB and device simulation is done by ATLAS. [ABSTRACT FROM AUTHOR]

Comparative assessment of graded channel gate stack (GCGS) DG MOSFET structure is done by using two-dimensional (2D) Sentrausu TCAD simulator for different high K oxide thickness. This novel device includes gate stack (GS) engineering (high K) and nonuniformly channel engineering (GC) to suppress the short channel effects and improve the device performance. This novel device can be a better alternative for the future high speed switching and low power circuit applications. It has the advantage of improved breakdown voltage, reduced leakage current, low output conductance and reduced bipolar parasitic effects. The given device must be properly investigated with respect to the variation of different high K oxide thickness on different parameters such as drain induced barrier lowering (DIBL), subthreshold slope (SS), /, roll off before fabrication to have better reliability. The 2D Sentrausu TCAD simulator using drift-diffusion model was used to simulate the developed structure and good agreement is obtained with respect to already published result in the sub-threshold regime. The result indicates that there is a need to be optimize the DC parameters for specific circuit applications. In this work, we studied the DC and SCEs of the Graded Channel Gate Stack-DG MOSFETs with variation of high-K oxide thickness for different channel length with the help of TCAD simulator. The study gives us an idea that proper optimization of high-K oxide thickness for specific channel length is essential for specific DC applications and also to limit the short channel effects. This novel device can be a better alternative for the future high speed switching and low power circuit applications. [ABSTRACT FROM AUTHOR]

This paper presents a detailed study of theoretical performance of graphene field effect transistor (GFET) using analytical approach. GFET shows promising performance in terms of faster saturation as well as extremely high cutoff frequency (3.9THz). A significant shift of the Dirac point as well as an asymmetrical ambipolar behavior is observed on the transfer characteristics. Similarly, an approximate symmetrical capacitance-voltage ( C- V) characteristics is obtained where it has guaranteed the consistency because it shows a significant saturation both in the accumulation and inversion region. In addition, a high transconductance of 6800uS at small channel length (20nm) along with high cutoff frequency (3.9THz) has been observed which demands for high speed field effect devices. [ABSTRACT FROM AUTHOR]

This paper deals with the performance of both gate and drain control coefficients to analyze the behavior of carbon nanotube field effect transistors (CNTFETs) under ballistic conditions and based on the change of different parameter value, such as oxide thickness of structure and temperature variation. A thorough study of both gate and drain control coefficient effects on the performance of CNTFETs has been conducted under different temperature and oxide layers and the output of the device has been analyzed through different parameters. Higher values of control coefficient help to attain larger transconductance by the increasing temperatures. For a fixed value of control coefficient, 4nm thickness of oxide has a transconductance of 4.5 10 S/m. Smaller oxide layer thickness has higher slope of increment in transconductance value. ON-state current to leakage current ratio shows a steady state response toward increment of gate control coefficient. Also, increment of oxide thickness has an adverse effect on current ratio, while a linear decay of current ratio is observed with the increased value of drain controlled one. Drain-induced battery lowering (DIBL) effect decreases with the value of gate control one and increases with the drain control coefficient. In this way, the optimum value for both the control coefficients has to be considered in order to perform well. [ABSTRACT FROM AUTHOR]

We numerically investigate the transmission of time-modulated random point trains in a conductance-based neuron model by including shot noise described as additive noise trains. The results show that additive noise trains can induce neuron responses exhibiting correlation with the temporally modulated random point trains. In addition, the additive noise power density can be increased up to an optimal value where the output signal-noise ratio (SNR) reaches a maximum value. This property of noise-enhanced transmission of random point trains can be related to the stochastic resonance (SR) phenomenon. More interestingly, we find that the SNR gain can exceed unity and can also be optimized by tuning the average rate of the input random point trains. The present study illustrates the potential to utilize the additive noise and temporally modulated random point trains for optimizing the response of the neuron to inputs, as well as a guidance in the design of information processing devices to random neuron spiking. [ABSTRACT FROM AUTHOR]

In this paper, we study ballistic thermal transport properties at low temperatures in semiconductor nanowires-based heterojunctions under hard-wall boundary conditions (HWBCs) and stress-free boundary conditions (SFBCs). Here, the numerical calculations for the asymmetric heterojunction (ASHJ) and symmetric heterojunction (SHJ) are done. When SFBCs are employed, the transmission coefficient exhibits different behaviors between ASHJ and SHJ especially at low frequency, but when HWBCs are employed, the transmission coefficient displays similar smooth platforms in both heterojunctions. In low temperature limit, the quantized thermal conductance can be observed in SHJ under SFBCs regardless of the structural details. However, this quantization cannot be observed in ASHJ under SFBCs, and the thermal conductance is strongly sensitive to the transverse width ratio rather than the slant angle. With increasing the transverse width ratio, the thermal conductance in both heterojunctions gradually increases especially, and such the increasing degree is more evident at higher temperatures. A brief analysis of these results is given. [ABSTRACT FROM AUTHOR]

This paper proposes a high data rate, low-power, low-voltage design of OTA-based M-ary ASK, FSK and QAM modulator and demodulator circuits. Conventional D/A converter of M-ary circuit has been replaced with the operational transconductance amplifier-based n-bits to 2n level converter which operates with input frequencies up to 2.1 GHz. OTA-based oscillator and PLL is being designed for high speed M-ary FSK. Eye diagram analysis has been carried out, conforming a very low signal distortion. Theoretical analysis of bit error rate has been done. The circuit analysis and simulation results confirm the reliability and accuracy of the design. Effective layouts and die photographs of the proposed designs are also presented. [ABSTRACT FROM AUTHOR]

In this paper, we proposed a novel relaxation oscillator to address the frequency variation caused by the comparator delay. The conventional operational transconductance amplifiers (OTAs)-comparator is replaced with a Schmitt trigger to significantly reduce the delay. This Schmitt trigger is implemented by a differential structure operating in the subthreshold region to generate a proportional to absolute temperature (PTAT) hysteresis. Both the voltage reference and the current source are made PTAT as well. The proposed oscillator can be made ultra-low power and have excellent frequency stability over process, voltage and temperature (PVT) variation. [ABSTRACT FROM AUTHOR]

We used atomic-layer molecular beam epitaxy (ALL-MBE) to synthesize bilayer films of a cuprate metal (, LSCO) and a cuprate insulator (, LCO), in which interface superconductivity occurs in a layer that is just one-half unit cell thick. We have studied the magnetic field and temperature dependence of the complex sheet conductance, , of these films, and compared them to -(BEDT-TTF) single crystals. The magnetic field was applied both parallel and perpendicular to the 2D conducting layers. Experiments have been carried out at frequencies between 23 kHz and 50 MHz using either two-coil mutual inductance technique, or the LC resonators with spiral or rectangular coils. The real and the imaginary parts of the mutual-inductance between the coil and the sample were measured and converted to complex conductivity. For perpendicular to the conducting layers, we observed almost identical behavior in both films and -Br single crystals: (i) the transition onset in the inductive response, (T) occurs at a temperature lower by 2 K than in , (ii) this shift is almost constant with magnetic field up to 8 T; (iii) the vortex diffusion constant is exponential due to pinning of vortex cores. These results can be described by the extended dynamic theory of the Berezinski-Kosterlitz-Thouless (BKT) transition and dynamics of bound vortex-antivortex pairs with short separation lengths. [ABSTRACT FROM AUTHOR]

It is shown that the Kubo equation for the Hall conductance can be expressed as an integral which implies quantization of the Hall conductance. The integral can be interpreted as the first Chern class of a principal fiber bundle on a two-dimensional torus. This accounts for the conductance given as an integer multiple of . The formalism can be extended to deduce the fractional conductivity as well. [ABSTRACT FROM AUTHOR]

metal-semiconductor (MS) and metal-ferroelectric-semiconductor (MFS) structures were fabricated and admittance measurements were held between 5 kHz and 1 MHz at room temperature so that dielectric properties of these structures could be investigated. The ferroelectric interfacial layer decreased the polarization voltage by providing permanent dipoles at metal/semiconductor interface. Depending on different mechanisms, dispersion behavior was observed in dielectric constant, dielectric loss and loss tangent versus bias voltage plots of both MS and MFS structures. The real and imaginary parts of complex modulus of MFS structure take smaller values than those of MS structure, because permanent dipoles in ferroelectric layer cause a large spontaneous polarization mechanism. While the dispersion in AC conductivity versus frequency plots of MS structure was observed at high frequencies, for MFS structure it was observed at lower frequencies. [ABSTRACT FROM AUTHOR]

This paper examines the effects of current and conductance noises in a minimal Hodgkin-Huxley type model of a cold receptor neuron. Current noise enters the membrane equation directly while conductance noise is propagated through the activation variables. Compared with common used interspike interval method, ISI-distance is a simple complementary approach to measure the different effects of current and conductance noises. ISI-distance extracts information from the interspike intervals by evaluating the ratio of instantaneous firing rates, which is parameter-free, time scale-independent and easy to visualize. Simulation results show that the most significant differences between different noise implementations in a pacemaker-like tonic firing regime at the transition to chaotic burst discharges. [ABSTRACT FROM AUTHOR]

In this paper, novel carbon nanotube (CNT) based operational transconductance amplifiers (OTAs) have been designed and simulated. Three types of CNT-based OTAs have been designed at 45 nm technology node and have been compared with the conventional CMOS-based OTA. The comparative analysis of the key characteristics of all the devices has revealed that a significant improvement in performance is observed in the CNT-based OTAs, particularly in a pure CNT-OTA. In the pure CNT-OTA, DC gain has increased by 218%, slew rate has increased by 22.58%, the output resistance has increased by 55.2% and the power consumption is ∼ 193 times less in comparison to the conventional CMOS-OTA. Further, common mode rejection ratio (CMRR) and power supply rejection ratio positive (PSRR+) has increased by 31.87% and 136.3%, respectively in pure CNT-OTA. The performance of CNT-based OTAs has also been studied thoroughly by varying the number of CNTs (N), CNT pitch (S) and the diameter of CNTs (DCNT) at 0.9 V. It has been observed that their performance can be improved further by using optimized values of CNT number; inter CNT-pitch and diameter. The stability analysis has shown that the pure CNT-OTA is highly stable. A 16.7% and 4% increase in phase and gain margins is achieved in the pure CNT-OTA in comparison to the bulk CMOS OTA. Finally, band and high pass filters have been realized by using the proposed CNT-based OTAs. [ABSTRACT FROM AUTHOR]

By using Gm-C compensation (GCC) technique, a two-stage recycling folded cascode (FC) operational transconductance amplifier (OTA) is designed. The proposed configuration consists of recycling structure, positive feedback and feed-forward compensation path. In comparison with the typical folded cascode CMOS Miller amplifier, this design has higher DC gain, unity-gain frequency (UGF), slew rate and common mode rejection ratio (CMRR). The presented OTA is simulated in 0.18-μm CMOS technology and the simulation results confirm the theoretical analyses. Finally, the proposed amplifier has a 111 dB open-loop DC gain, 20 MHz UGF and 145 dB CMRR @ 1.2 V supply voltage while the power consumption is 400 μW which makes it suitable for low-voltage applications. [ABSTRACT FROM AUTHOR]