DC Response Research Articles

Ant colony based optimization model for QoS-based task scheduling in cloud computing environment

Cloud computing has evolved with various techniques for satisfying the needs of users to reduce costs and offer better results. The users' needs may include sharing of resources like memories, processors, apps, information, data, applications, etc., whereas, performance should be in terms of improved DC processing period & response time. Apart from the above-said, there is also a requirement to manage the stability of the system and be flexible to make amendments to the system. Static data is used to optimize the project schedule. However, the traditional does not take into account the personnel allocation matrix when scheduling projects. The ACO model is not a suitable solution to the scheduling problem. The classic ACO methodology operates in two phases: the first phase uses an event-based scheduler to address the complex planning issue. Planning and allocating resources for a project are both constrained by these two approaches. The event-based ACO model was developed to match the resource restrictions and activity schedule to handle dynamic data allocation. When it comes to multi-objective scheduling, EBS with ACO is not an adequate approach. An updated ACO technique to optimum global search employing a neural network approach was presented to schedule many activities to tackle the difficulty of multiple objectives. Using the suggested multi-objective technique, an activity with a defined number of tasks and necessary resources may be optimally organized. The algorithm LBACO is the most effective one to apply for optimizing the objective function, according to the test results, as well as the fastest. An advantage of ACO over other techniques is its ability to provide better plans with higher statistics and mean access times, as well as more consistent job assignments.

A SiGe/Si Phototransistor With High FOM of Gain*VA Using 0.35-μm BiCMOS Technology

A novel SiGe/Si phototransistor with high figure of merit (FOM) of gain*early voltage for optical communication was designed and fabricated in a standard 0.35- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> BiCMOS process. A compound base consisting of a P-Si layer and a P+-SiGe layer was designed to achieve a good optical response through relieving the negative influence induced by doped ion’s mutual diffusion in device fabrication. The fabricated surface-illuminated SiGe/Si heterojunction phototransistor (HPT) was measured under 850-nm incident light with a variety of optical powers at 1-V collector bias. When the incident optical power was <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.29~\mu \text{W}$ </tex-math></inline-formula> , the collector current reached <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.45~\mu \text{A}$ </tex-math></inline-formula> . The maximum gain exceeded 6.925 with the dark current of about 100 pA. The FOM of gain*early voltage of the proposed SiGe/Si HPT can achieve 100.97. Its optical DC and RF responses under high light power were analyzed with a physically based simulation model, which considered the process effects of device fabrication detailed. The optical gain may promote to 13.3 but with the deteriorated output performance and a smaller early voltage. The maximum optical characteristic frequency may reach 17.6 GHz.

OFDM-Based Intrinsically Safe Power and Signal Synchronous Transmission for CC-PT-Controlled Buck Converters

Intrinsically safe power converters have been highly demanded in many harsh industrial environments, such as gas stations, chemical plants, and mine tunnels, to realize accurate voltage or current regulations with minimum safety risks. Communication among different devices is the key to realizing important operations, such as coordinated control, fault detection, and state update, for intrinsically safe converters. In this article, a capacitor current pulse train (CC-PT) control strategy is designed to increase the dynamic response of dc–dc converter with intrinsic operational safety. An orthogonal frequency-division multiplexing (OFDM) based power and signal synchronous transmission (PSST) method is then proposed. The mathematical models of signal modulation are established, and the intrinsic safety region is drawn in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L–C</i> parameters plane, considering the requirements of electric performance, the inductor disconnection discharging, and output short-circuit tests. Simulations and prototype experiments are conducted and presented to verify the feasibility of the OFDM-based PSST in the CC-PT-controlled buck converter with intrinsically safe parameters.

A comparative analysis of Danionella cerebrum and zebrafish (Danio rerio) larval locomotor activity in a light-dark test.

The genus Danionella comprises some of the smallest known vertebrate species and is evolutionary closely related to the zebrafish, Danio rerio. With its optical translucency, rich behavioral repertoire, and a brain volume of just 0.6 mm3, Danionella cerebrum (Dc) holds great promise for whole-brain in vivo imaging analyses with single cell resolution of higher cognitive functions in an adult vertebrate. Little is currently known, however, about the basic locomotor activity of adult and larval Danionella cerebrum and how it compares to the well-established zebrafish model system. Here, we provide a comparative developmental analysis of the larval locomotor activity of Dc and AB wildtype as well as crystal zebrafish in a light-dark test. We find similarities but also differences in both species, most notably a striking startle response of Dc following a sudden dark to light switch, whereas zebrafish respond most strongly to a sudden light to dark switch. We hypothesize that the different startle responses in both species may stem from their different natural habitats and could represent an opportunity to investigate how neural circuits evolve to evoke different behaviors in response to environmental stimuli.

High kinetic inductance NbTiN superconducting transmission line resonators in the very thin film limit

We examine the DC and radio frequency (RF) response of superconducting transmission line resonators comprised of very thin NbTiN films, &amp;lt;12 nm in thickness, in the high-temperature limit, where the photon energy is less than the thermal energy. The resonant frequencies of these superconducting resonators show a significant nonlinear response as a function of RF input power, which can approach a frequency shift of Δf=−0.15% in a −20 dB span in the thinnest film. The strong nonlinear response allows these very thin film resonators to serve as high kinetic inductance parametric amplifiers.

Kerr and Faraday rotations in topological flat and dispersive band structures

Integer quantum Hall (IQH) states and quantum anomalous Hall (QAH) states show the same static dc response but distinct dynamical ac response. In particular, the ac anomalous Hall conductivity profile σ yx (ω) is sensitive to the band shape of QAH states. For example, dispersive QAH bands shows resonance profile without a sign change at the band gap while the IQH states shows the sign change resonance at the cyclotron energy. We argue by flattening the dispersive QAH bands, σ yx (ω) should recover to that of flat Landau bands in IQH, thus it is necessary to know the origin of the sign change. Taking a topological lattice model with tunable bandwidth, we found that the origin of the sign change is not the band gap but the van Hove singularity energy of the QAH bands. In the limit of small bandwidth, the flat QAH bands recovers σ yx (ω) of the IQH Landau bands. Because of the Hall response, these topological bands exhibit giant polarization rotation and ellipticity in the reflected waves (Kerr effect) and rotation in the order of fine structure constant in the transmitted waves (Faraday effect) with profile resembles σ yx (ω). Our results serve as a simple guide to optical characterization for topological flat bands.

IgA and FcαR are critical components of plasmacytoid DC response to autoantibody-containing immune complexes in SLE.

Abstract Systemic lupus erythematosus (SLE) is a heterogenous autoimmune disease characterized by the presence of circulating autoreactive anti-nuclear antibodies (ANAs). ANAs form immune complexes (ICs) upon binding to nuclear antigens and these ANA-ICs promote a feedforward loop by enhancing immune responses in cells that recognize ANA-ICs via Fc receptors (FcRs). Plasmacytoid dendritic cells (pDCs) are FcR expressing cells that promote SLE pathology. ANA-ICs deliver nucleic acids to endosomal TLR7 and TLR9. These TLRs induce type I IFN secretion and immune activation upon nucleic acid recognition. Type I IFNs, including IFNα, and interferon stimulated genes are correlated with SLE disease activity. IgG isotype facilitated ANA-IC internalization via FcgRIIA has been the most studied antibody-mediated route for IFNα production in pDCs. The importance of IgA isotype ANAs remains under investigated despite these autoantibodies being present in half of SLE patients. We show here the novel result that human pDCs express the IgA-specific FcαR (CD89) by flow cytometry, that pDCs from SLE patients express increased FcαR compared to pDCs from healthy controls, and that increased pDC FcαR expression in SLE correlates with hallmark IFNα gene set. Additionally, we found that IgA autoantibodies were a critical component of pDC ANA-IC activation when these ANA-IC were generated with serum from IgA autoantibody positive SLE donors complexed with smRNP nuclear antigen. Therefore, our study shows that IgA-containing immune complexes and FαRI are important contributors to pDC type I IFN production in SLE. Supported by LRA Lupus Mechanisms and Targets Award (JAH), R21AI154841 (JAH), and ITHS TL1 training grant (HRW).

MPPT Control of Grid Connected DFIG at Variable Wind Speed

In this study, maximum power point tracking (MPPT) control of a grid-connected doubly fed induction generated (DFIG)-based wind energy conversion system (WECS) at variable wind speed was designed and analyzed. The real wind speed data of the Edremit/Balıkesir region in Turkey was used as the wind speed profile. A N90/2.5 MW wind turbine model of Nordex Company was used in the study. Firstly, a conventional PI controller was applied to both rotor and grid side converters. The rotor-side converter (RSC) controls the power generated from the DFIG, whereas the grid-side converter (GSC) controls the DC bus voltage. An MPPT controller was applied to the RSC to generate reference torque at instant variable wind speeds. Thus, the system’s response time, electromagnetic torque, generated power, and grid-side currents parameters were improved. In the MPPT controller, the reference torque value is produced by using the angular velocity and reference angular velocity values of the DFIG. The proposed system was modeled and simulated in Matlab/Simulink. Generated power, DC bus voltage, response time, electromagnetic torque, and grid side currents results were obtained. The results of the conventional PI controller and the results of the PI controller with MPPT were compared. The results of the proposed control were also compared with the related studies. The results showed that the proposed system is reliable, applicable, and valid for the grid-connected DFIG at variable wind speeds.

DC response, low-frequency noise, and TID-induced mechanisms in 16-nm FinFETs for high-energy physics experiments

Total-ionizing-dose (TID) mechanisms are evaluated in 16 nm Si bulk FinFETs at doses up to 1 Grad(SiO2) for applications in high-energy physics experiments. The TID effects are evaluated through DC and low-frequency noise measurements by varying irradiation bias conditions, transistor channel lengths, and fin/finger layouts. The TID response of nFinFETs irradiated under positive gate bias at ultrahigh doses shows a rebound of threshold voltage with significant increase in the 1/f noise amplitude. The degradation is related to the generation of border and interface traps at the upper corners of STI oxides and at the gate oxide/channel interfaces. In contrast, pFinFETs have the worst degradation due to positive charge trapping in STI oxides, which severely degrades the device transconductance and total drain current, while negligible effects are visible in the threshold voltage and 1/f noise. The TID sensitivity depends strongly on the transistor layout. Short-channel devices have the best TID tolerance thanks to the influence of halo implantations, while pFinFETs designed with low number of fins have the worst degradation because of high densities of positive charge in the surrounding thick STI oxides. As a guideline for IC design, short-channel transistors with more than 4-fins may be preferred in order to facilitate circuit qualification.

Dendritic cell functions in vivo: A user's guide to current and next- generation mutant mouse models.

DCs do not just excel in antigen presentation. They orchestrate information transfer from innate to adaptive immunity by sensing and integrating a variety of danger signals, and translating them to naïve T cells, to mount specifically tailored immune responses. This is accomplished by distinct DC types specialized in different functions and because each DC is functionally plastic, assuming different activation states depending on the input signals received. Mouse models hold the key to untangle this complexity and determine which DC types and activation states contribute to which functions. Here, we aim to provide comprehensive information for selecting the most appropriate mutant mouse strains to address specific research questions on DCs, considering three in vivo experimental approaches: (i) interrogating the roles of DC types through their depletion; (ii) determining the underlying mechanisms by specific genetic manipulations; (iii) deciphering the spatiotemporal dynamics of DC responses. We summarize the advantages, caveats, suggested use, and perspectives for a variety of mutant mouse strains, discussing in more detail the most widely used or accurate models. Finally, we discuss innovative strategies to improve targeting specificity and next-generation mutant mouse models, and briefly address how humanized mouse models can accelerate translation into the clinic.

Exchange coupling-mediated broken symmetries in Ta2NiSe5 revealed from quadrupolar circular photogalvanic effect.

In low–electron density materials, interactions can lead to highly correlated quantum states of matter. Ta2NiSe5, an excitonic insulator (EI) candidate, exists in a novel broken-symmetry phase below 327 K, characterized by robust exchange interaction and electron-lattice coupling. We study this phase of Ta2NiSe5 using the quadrupole circular photogalvanic effect (QCPGE). Light-matter interaction in Ta2NiSe5 mediated by electric quadrupole/magnetic dipole coupling produces helicity-dependent DC response even with centrosymmetry, making it particularly sensitive to certain other broken symmetries. We show that the exchange interaction in Ta2NiSe5 can lead to a triclinic structure with a broken C2 symmetry. Our results provide an incisive probe of the symmetries of the low-temperature phase of Ta2NiSe5 and add new symmetry constraints to the identification of a strongly correlated EI phase. The high sensitivity of QCPGE to subtle symmetry breaking in centrosymmetric systems will enable its use in studying other complex crystalline systems.

A kinetic derivation of a Butler-Volmer-like equation for the current-voltage characteristics in an adsorbing medium

The DC response of an electrochemical system submitted to an external difference of potential, is investigated by means of the Poisson-Nernst-Planck model. We suppose that only positive ions are injected into the electrochemical cell by the electrodes. For the injection mechanism we assume that it is well described by Nernst model, where the injected bulk density of ions depends on the difference of electric potential between the electrode and the bulk. Our goal is the determination of the current–voltage characteristics. We show that the functional dependence of the current density on the applied difference of potential is similar to that predicted by the Butler–Volmer equation relevant to an electrolytic cell submitted to an external difference of electric potential.

TLR ligand ligation switches adenosine receptor usage of BMDCs leading to augmented Th17 responses in experimental autoimmune uveitis

The extracellular level of adenosine increases greatly during inflammation, which modulates immune responses. We have previously reported that adenosine enhances Th17 responses while it suppresses Th1 responses. This study examined whether response of DC to adenosine contributes to the biased effect of adenosine and determined whether adenosine and TLR ligands have counteractive or synergistic effects on DC function. Our results show that adenosine is actively involved in both in vitro and in vivo activation of pathogenic T cells by DCs; however, under adenosine effect DCs' capability of promoting Th1 versus Th17 responses are dissociated. Moreover, activation of A2ARs on DCs inhibits Th1 responses whereas activation of A2BRs on DC enhances Th17 responses. An intriguing observation was that TLR engagement switches the adenosine receptor from A2ARs to A2BRs usage of bone marrow-derived dendritic cells (BMDCs) and adenosine binding to BMDCs via A2BR converts adenosine's anti-to proinflammatory effect. The dual effects of adenosine and TLR ligand on BMDCs synergistically enhances the Th17 responses whereas the dual effect on Th1 responses is antagonistic. The results imply that Th17 responses will gain dominance when inflammatory environment accumulates both TLR ligands and adenosine and the underlying mechanisms include that TLR ligand exposure has a unique effect switching adenosine receptor usage of DCs from A2ARs to A2BRs, via which Th17 responses are promoted. Our observation should improve our understanding on the balance of Th1 and Th17 responses in the pathogenesis of autoimmune and other related diseases.

High-power InAlAs/InGaAs Schottky barrier photodiodes for analog microwave signal transmission

The design, manufacturing and DC and microwave characterization of high-power Schottky barrier InAlAs/InGaAs back-illuminated mesa structure photodiodes are presented. The photodiodes with 10 and 15 μm mesa diameters operate at ≥40 and 28 GHz, respectively, have the output RF power as high as 58 mW at a frequency of 20 GHz, the DC responsivity of up to 1.08 A/W depending on the absorbing layer thickness, and a photodiode dark current as low as 0.04 nA. We show that these photodiodes provide an advantage in the amplitude-to-phase conversion factor which makes them suitable for use in high-speed analog transmission lines with stringent requirements for phase noise.

Quantitative Mapping of Unmodulated Temperature Fields with Nanometer Resolution.

Quantitative mapping of temperature fields with nanometric resolution is critical in various areas of scientific research and emerging technology, such as nanoelectronics, surface chemistry, plasmonic devices, and quantum systems. A key challenge in achieving quantitative thermal imaging with scanning thermal microscopy (SThM) is the lack of knowledge of the tip-sample thermal resistance (RTS), which varies with local topography and is critical for quantifying the sample temperature. Recent advances in SThM have enabled simultaneous quantification of RTS and topography in situations where the temperature field is modulated enabling quantitative thermometry even when topographical features cause significant variations in RTS. However, such an approach is not applicable to situations where the temperature modulation of the device is not readily possible. Here we show, using custom-fabricated scanning thermal probes (STPs) with a sharp tip (radius ∼25 nm) and an integrated heater/thermometer, that one can quantitatively map unmodulated temperature fields, in a single scan, with ∼7 nm spatial resolution and ∼50 mK temperature resolution in a bandwidth of 1 Hz. This is accomplished by introducing a modulated heat input to the STP and measuring the AC and DC responses of the probe's temperature which allow for simultaneous mapping of the tip-sample thermal resistance and sample surface temperature. The approach presented here─contact resistance resolved scanning thermal microscopy (CR-SThM)─can greatly facilitate temperature mapping of a variety of microdevices under practical operating conditions.

The Fusion Protein rFlaA:Betv1 Modulates DC Responses by a p38-MAPK and COX2-Dependent Secretion of PGE2 from Epithelial Cells.

Developing new adjuvants/vaccines and better understanding their mode-of-action is an important task. To specifically improve birch pollen allergy treatment, we designed a fusion protein consisting of major birch pollen allergen Betv1 conjugated to the TLR5-ligand flagellin (rFlaA:Betv1). This study investigates the immune-modulatory effects of rFlaA:Betv1 on airway epithelial cells. LA-4 mouse lung epithelial cells were stimulated with rFlaA:Betv1 in the presence/absence of various inhibitors with cytokine- and chemokine secretion quantified by ELISA and activation of intracellular signaling cascades demonstrated by Western blot (WB). Either LA-4 cells or LA-4-derived supernatants were co-cultured with BALB/c bone marrow-derived myeloid dendritic cells (mDCs). Compared to equimolar amounts of flagellin and Betv1 provided as a mixture, rFlaA:Betv1 induced higher secretion of IL-6 and the chemokines CCL2 and CCL20 from LA-4 cells and a pronounced MAPK- and NFκB-activation. Mechanistically, rFlaA:Betv1 was taken up more strongly and the induced cytokine production was inhibited by NFκB-inhibitors, while ERK- and p38-MAPK-inhibitors only suppressed IL-6 and CCL2 secretion. In co-cultures of LA-4 cells with mDCs, rFlaA:Betv1-stimulated LA-4 cells p38-MAPK- and COX2-dependently secreted PGE2, which modulated DC responses by suppressing pro-inflammatory IL-12 and TNF-α secretion. Taken together, these results contribute to our understanding of the mechanisms underlying the strong immune-modulatory effects of flagellin-containing fusion proteins.

Conceptual framework on teaching capacitors and inductors

The objective of this work is to suggest a conceptual framework on teaching capacitors and inductors in order to improve teaching abilities and to eliminate some fundamental misconceptions. The effort initially deals with resolution of physical structure and structural concepts/parameters of the devices and then resolves DC and AC responses of the inductors and capacitors. The resolutions are achieved by considering basic serious RL and RC circuits and resolving the circuits both theoretically and experimentally. As a result, an alternative teaching approach is offered and also a novel instructional material is developed and suggested. Some teaching clues are briefly inserted to guide teachers/instructors to reach a higher comprehension level. It is believed that the implications of the developed teaching material would be quite high and beneficial.

Baccharis trimera (Less.) DC responses to water restriction

Climate change can cause imbalances in plants. Baccharis trimera is a specie usually found in harsh conditions and has medicinal and agricultural properties. Thus, this study aimed to evaluate the biochemical and physiological responses of this plant under water restriction (WR) levels. B. trimera samples were identified and collected in Erechim/RS and propagated in a greenhouse. When acclimated, they were subjected to 0, 25, 75 and 100% WR, determined according to the water saturation in the soil by capillary action. After 30 days of treatment, the physiological responses: growth, and fresh and dry biomass; and the biochemical responses: activity of superoxide dismutase (SOD), guaiacol peroxidase (GP) and ascorbate peroxidase (APX) enzymes, proline, protein and hydrogen peroxide content, and lipid peroxidation, were determined. Data were submitted to regression analysis and Pearson correlation. The WR of 27.37%, on average, induced an increase in physiological parameters, but the root growth was impaired in conditions above 50% of WR. With the increase in WR there was an increase in the activity of SOD in the shoot and APX in the root. In low WR conditions, proline contents were maintained. Therefore, with low levels of WR, around 27%, B. trimera has increase in root growth and root and shoot biomass. Proline, and SOD and APX activity are a pathway that scavenging the stress generated by WR on B. trimera.

Oscillation in the electrical conductivity of a thick graphene oxide membrane

Because of their unusual fundamental behavior that arises at the molecular scale, the electrical conductivity of stacked graphene oxide (GO) sheets in the presence of external parameters is not adequately understood. Previous studies concentrated on the DC response of thin GO membranes giving their resistive switching properties. Here, we observe anomalous low-frequency (&amp;lt;1 Hz) oscillations in the electrical conductivity of micrometer size GO, which is repeated in a process over and over in an ongoing feedback loop. Such vibrations and their unique trajectories are not only fundamentally important but also have characteristic frequencies that can be directly linked to the formation and destruction of regions with sp2 hybridization. Also, the reported switching time (of the order of seconds) makes our resistive switching system different than all the previously reported systems and introduces a new class of switching phenomena. The observed phenomena improve our understanding of the electrical conductivity of GO membranes and the corresponding microscopic details that pave the way for the promising application of these new observed low-frequency oscillations.

Uncooled CMOS 2.5THz detector comprising a metamaterial absorber loaded with resistors and a PTAT sensor

Terahertz (THz) detectors have shown a multitude of important prospects in the fields of THz technology. This paper presents an innovative metamaterial (MM) absorber combined with a temperature sensor, leading to a new type of room-temperature CMOS THz thermal detector. The innovative MM absorber implemented in the 55 nm CMOS process is presented across the THz frequency range for the first time. It is based on a loop resonator loaded with four polysilicon resistors for higher responsivity. The theoretical analysis, multi-physics simulations and experimental validations of the detector are presented in detail. Experimental results of detectors loaded with polysilicon resistors and without polysilicon resistors are obtained at 2.5 THz for comparison. The proposed detector loaded with resistors shows a DC responsivity of 57.1 V/W and a noise equivalent power (NEP) of 0.21 μW/√Hz. The detector without resistors achieves a DC responsivity of 20.18 V/W with a NEP of 0.59 μW/√Hz at 30 Hz. The presented novel detector could be easily scaled to array formats, showing significant potentials toward room-temperature, compact, inexpensive, easy-integration and high-yield THz detection systems.