Gating Technique Research Articles

Ultrahigh-amplitude isolated attosecond pulses generated by a two-color laser pulse interacting with a microstructured target.

A unique electron nanobunching mechanism using a two-color laser pulse interacting with a microstructured foil is proposed for directly generating ultraintense isolated attosecond pulses in the transmission direction without requiring extra filters and gating techniques. The unique nanobunching mechanism ensures that only one electron sheet contributes to the transmitted radiation. Accordingly, the generated attosecond pulses are unipolar and have durations at the full width at half-maximum about 5 attoseconds. The emitted ultrahigh-amplitude isolated attosecond pulses have intensities of up to ∼10^{21}W/cm^{2}, which are beyond the limitations of weak attosecond pulses generated by gas harmonics sources and may open a new regime of nonlinear attosecond studies. Unipolar pulses can be useful for probing ultrafast electron dynamics in matter via asymmetric manipulation.

Low voltage EX-CCCII based on quasi-floating gate technique and its application as precision rectifier

This paper introduces a novel low-voltage low-power Extra-X Current Controlled Current Conveyor (EX-CCCII) based on quasi floating gate (QFG) MOSFET. The QFG technique is employed in low voltage applications and overcomes the limitation of the floating gate technique. The presented circuit is implemented at a supply voltage of ±0.5 V with a power consumption of 90 µW at 20 µA bias current. As an application, the proposed QFG based EX-CCCII is employed to realize a novel current mode precision rectifier circuit. This circuit can simultaneously provide positive and negative type half wave and full wave rectifiers with the same circuit configuration. Furthermore, the rectifier circuit has low input and high output impedance terminals making it suitable for cascading with other current mode circuits. All the results provided to verify the circuit performance are simulated using CADENCE VIRTUOSO SPECTRE simulator with 0.18 µm UMC CMOS technology process parameters. The simulation results confirm the theoretical concept.

Tuning of spin relaxation and the Kondo effect in copper thin films by ionic gating

Spin relaxation length is a fundamental material parameter that influences all aspects of spin dependent transport. The ability to tune the spin relaxation length leads to novel spintronic phenomena and functionalities. We explore the tunability of the spin relaxation length in the mesoscopic Cu channels of nonlocal spin valves by using the ionic gating technique via a ${\mathrm{Li}}^{+}$ containing solid polymer electrolyte. At 5 K, the Cu spin relaxation length ${\ensuremath{\lambda}}_{\mathrm{Cu}}$ is tuned reversibly between 670 and 410 nm and the Cu resistivity ${\ensuremath{\rho}}_{\mathrm{Cu}}$ is tuned by 9%. The strength of the Kondo effect due to the Fe impurities in Cu is tuned by one order of magnitude. At 295 K, ${\ensuremath{\lambda}}_{\mathrm{Cu}}$ is tuned between 380 and 300 nm and ${\ensuremath{\rho}}_{\mathrm{Cu}}$ is tuned by 7%. A gradual amplification of the tuning ranges by repeated gate cycling is observed and clearly suggests an electrochemical origin. Tunable spin relaxation in simple metals enriches functionalities in metal-based spintronics and shines light on fundamental spin relaxation mechanisms.

Intense isolated attosecond pulses from two-color few-cycle laser driven relativistic surface plasma

Ultrafast plasma dynamics play a pivotal role in the relativistic high harmonic generation, a phenomenon that can give rise to intense light fields of attosecond duration. Controlling such plasma dynamics holds key to optimize the relevant sub-cycle processes in the high-intensity regime. Here, we demonstrate that the optimal coherent combination of two intense ultrashort pulses centered at two-colors (fundamental frequency, omega and second harmonic, 2omega) can lead to an optimal shape in relativistic intensity driver field that yields such an extraordinarily sensitive control. Conducting a series of two-dimensional (2D) relativistic particle-in-cell (PIC) simulations carried out for currently achievable laser parameters and realistic experimental conditions, we demonstrate that an appropriate combination of omega -2omega along with a precise delay control can lead to more than three times enhancement in the resulting high harmonic flux. Finally, the two-color multi-cycle field synthesized with appropriate delay and polarization can all-optically suppress several attosecond bursts while favourably allowing one burst to occur, leading to the generation of intense isolated attosecond pulses without the need of any sophisticated gating techniques.

Prediction of Intermittent Failure by Presage Debacle Model in Network on Chip

With the emergence of deep sub-micron technology, the reliability issues in on-chip interconnect has enormously increased. This includes single event upsets, like soft errors, and hard faults which are rapidly becoming important factors to be considered. Aggressive technology scaling renders these architectures vulnerable to system performance, intermittent failure, capacitive crosstalk, and power dissipation problem. To improve the performance of the area and power consumption along with bandwidth, throughput and latency, a Buffer Potency Power Gating Technique is carried out to predict the Intermittent Failure by Presage Debacle Model in Network on Chip. In the Presage Debacle Model, the links present in the application-specific topology are provided with real application traffic to assist in prediction of the intermittent failure. By predicting the failure, the output of the model provides the power dissipated over the connection of the application link. Then the crosstalk noise in the topology is reduced by the Adaption of Simulated Annealing (SA) based Particle Swarm Optimization (PSO) congruence algorithm. The optimization congruence algorithm assigns each task in the application software to each node in the topology to determine the network's optimal output. It continuously changes the task park position in the topology system and reduces the crosstalk of the NoC. Consecutively, the area and power consumption are minimized by Buffer Potency Power Gating Technique. Buffer efficiency is increased and the power-gating is a practical way to mitigate NoC power control schemes properly and effectively without any loss in performance. Thus the prediction of intermittent failure is obtained by utilizing NoC to improve the performance of area and power consumption.

VLSI Implementation of Low Power FIR Filter using Variable Precision Two-Dimensional Pipeline Gating Multiplier

The low-power FIR filter is required for many DSP applications. The crucial and powerhungry block in the filter is a multiplier. To implement the low power FIR filter a twodimensional variable precision fine-grain pipeline gating technique is introduced in the multiplier. The optimized multiplier is used to implement the transposed form-based FIR filter for the order N = 8 in ASIC design tools from Cadence in CMOS 45nm Technology. The designed FIR filter is compared with the existing multiplier-based FIR filters. The power-saving is achieved by the proposed filter is 22% without any degradation in the speed. The area penalty is 3% only due to the variable precision two-dimensional pipeline gating technique. Keywords: FIR filter, Fine grain pipeline, dynamic power, clock gating, low power multiplier, VLSI, and variable precision.

Electric field control of anomalous Hall effect in CaIrO3/CaMnO3 heterostructure

We demonstrate an electric field control of an anomalous Hall effect emerging in CaIrO3/CaMnO3 heterostructures. We fabricate both electron-type and hole-type carrier samples by tuning epitaxial strain and, then, control the carrier density in a CaIrO3 layer via electric double layer gating technique. As the Fermi energy of CaIrO3 is tuned close to the Dirac line node, anomalous Hall conductivity is enlarged in both carrier-type samples. This result reveals that the anomalous Hall effect comes from the intrinsic origin, reflecting the Dirac-like dispersion in CaIrO3. We propose that band splitting induced by the interface ferromagnetism yields several band crossing points near the Dirac line node. These points act as a source of the Berry curvature and contribute to the anomalous Hall effect.

Fetal Cardiovascular MRI - A Systemic Review of the Literature: Challenges, New Technical Developments, and Perspectives.

Fetal magnetic resonance imaging (MRI) has become a valuable adjunct to ultrasound in the prenatal diagnosis of congenital pathologies of the central nervous system, thorax, and abdomen. Fetal cardiovascular magnetic resonance (CMR) was limited, mainly by the lack of cardiac gating, and has only recently evolved due to technical developments. A literature search was performed on PubMed, focusing on technical advancements to perform fetal CMR. In total, 20 publications on cardiac gating techniques in the human fetus were analyzed. Fetal MRI is a safe imaging method with no developmental impairments found to be associated with in utero exposure to MRI. Fetal CMR is challenging due to general drawbacks (e. g., fetal motion) and specific limitations such as the difficulty to generate a cardiac gating signal to achieve high spatiotemporal resolution. Promising technical advancements include new methods for fetal cardiac gating, based on novel post-processing approaches and an external hardware device, as well as motion compensation and acceleration techniques. Newly developed direct and indirect gating approaches were successfully applied to achieve high-quality morphologic and functional imaging as well as quantitative assessment of fetal hemodynamics in research settings. In cases when prenatal echocardiography is limited, e. g., by an unfavorable fetal position in utero, or when its results are inconclusive, fetal CMR could potentially serve as a valuable adjunct in the prenatal assessment of congenital cardiovascular malformations. However, sufficient data on the diagnostic performance and clinical benefit of new fetal CMR techniques is still lacking. · New fetal cardiac gating methods allow high-quality fetal CMR.. · Motion compensation and acceleration techniques allow for improvement of image quality.. · Fetal CMR could potentially serve as an adjunct to fetal echocardiography in the future.. · Knapp J, Tavares de Sousa M, Schönnagel BP. Fetal Cardiovascular MRI - A Systemic Review of the Literature: Challenges, New Technical Developments, and Perspectives. Fortschr Röntgenstr 2022; 194: 841 - 851.

A 186μW Photoplethysmography-Based Noninvasive Glucose Sensing SoC

Recent trends in research and the market show high demand for frequent monitoring of glucose to estimate the blood sugar level non-invasively which can replace the conventional finger-prick glucometer for daily use. This paper presents a high precision near-infrared Photoplethysmography (PPG) based noninvasive glucose monitoring System on Chip (SoC). The proposed system implements a fully differential Analog Frontend (AFE) with nonlinear medium Gaussian support-vector-regression (NMG-SVR) for glucose estimation. The AFE design incorporates chopping which enables the reduction of the integrated input-referred current noise to 9.4pArms thus achieving a dynamic range of 115dB. The glucose prediction processor (GPP) removes noise from the PPG signal, extracts ten unique features, and estimates the blood glucose level using a trained customized NMG-SVR model that minimizes the hardware cost by 25%. The extracted features are carefully designed and implemented to ensure inter-feature dependency, which helps to reduce the overall area by more than 40%. Moreover, GPP is implemented using power and clock gating techniques to minimize both static and dynamic power consumption. The proposed SoC is realized with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.18~\mu \text{m}$ </tex-math></inline-formula> CMOS technology and occupies an area of 6 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . It dissipates a power of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$186~\mu \text{W}$ </tex-math></inline-formula> and achieves a mean absolute relative difference (mARD) of 6.9% verified on 200 subjects.

Discrete superconducting phases in proton-intercalated FeSe thin flakes

We have successfully manipulated the electronic properties of FeSe thin flakes based on a field-effect transistor with a solid proton conductor as the gate dielectric. The phase diagram as a function of gate voltage demonstrates three evident discrete superconducting phases with ${T}_{\mathrm{c}}$ corresponding to $\ensuremath{\sim}8, \ensuremath{\sim}34$, and $\ensuremath{\sim}42$ K, respectively, which is similar to those observed in ${\mathrm{Li}}_{x}\mathrm{FeSe}$ and ${\mathrm{Na}}_{x}\mathrm{FeSe}$ by tuning Li or Na content with the solid-ion-conductor gating technique. In the protonation process, the final state with a saturation of the amount of hydrogen ions is reached at a moderately low gate voltage. It suggests that such a device based on a proton conductor can be used to modulate the physical properties by controlling the intercalated proton content and to explore the hydrogen storage capacity of materials.

Automatic Liver Segmentation Using EfficientNet and Attention-Based Residual U-Net in CT.

This paper proposes a new network framework, which leverages EfficientNetB4, attention gate, and residual learning techniques to achieve automatic and accurate liver segmentation. First, we use EfficientNetB4 as the encoder to extract more feature information during the encoding stage. Then, an attention gate is introduced in the skip connection to eliminate irrelevant regions and highlight features of a specific segmentation task. Finally, to alleviate the problem of gradient vanishment, we replace the traditional convolution of the decoder with a residual block to improve the segmentation accuracy. We verified the proposed method on the LiTS17 and SLiver07 datasets and compared it with classical networks such as FCN, U-Net, attention U-Net, and attention Res-U-Net. In the Sliver07 evaluation, the proposed method achieved the best segmentation performance on all five standard metrics. Meanwhile, in the LiTS17 assessment, the best performance is obtained except for a slight inferior on RVD. The proposed method's qualitative and quantitative results demonstrated its applicability in liver segmentation and proved its good prospect in computer-assisted liver segmentation.

Floptics

Flow cytometry (FCM) determines the characteristics of individual biological cells using optical and fluorescence measurements. It is a widely used standard method for analysing blood samples in medical diagnostics, through identifying and quantifying the different types of cells in the samples. The multidimensional dataset obtained from FCM is large and complex, so it is difficult and time-consuming to analyse manually. The main process of differentiation and therefore labelling of the different cell populations in the data is referred to as Gating. This is the first step of FCM and is highly subjective, an issue that significant research has focussed on reducing. Existing automated gating techniques are time-consuming or retain subjectivity by requiring many user-defined parameters. This paper presents FLOPTICS: a novel automated gating technique that is a combination of density-based and grid-based clustering algorithms. FLOPTICS has an ability to classify and label cell populations in FCM data faster and with fewer user-defined parameters than many state-of-the-art techniques.

Magnetic Anisotropy Control with Curie Temperature above 400 K in a van der Waals Ferromagnet for Spintronic Device.

The technological appeal of van der Waals ferromagnetic materials is the ability to control magnetism under external fields with desired thickness toward novel spintronic applications. For practically useful devices, ferromagnetism above room temperature or tunable magnetic anisotropy is highly demanded but remains challenging. To date, only a few layered materials exhibit unambiguous ferromagnetic ordering at room temperature via gating techniques or interface engineering. Here, it is demonstrated that the magnetic anisotropy control and dramatic modulation of Curie temperature (Tc ) up to 400 K are realized in layered Fe5 GeTe2 via the high-pressure diamond-anvil-cell technique. Magnetic phases manifesting with in-plane anisotropic, out-of-plane anisotropic and nearly isotropic magnetic states can be tuned in a controllable way, depicted by the phase diagram with a maximum Tc up to 360 K. Remarkably, the Tc can be gradually enhanced to above 400 K owing to the Fermi surface evolution during a pressure loading-deloading process. Such an observation sheds light on the understanding and control of emergent magnetic states in practical spintronic applications.

Anomalous Metallic Phase in Molybdenum Disulphide Induced via Gate-Driven Organic Ion Intercalation

Transition metal dichalcogenides exhibit rich phase diagrams dominated by the interplay of superconductivity and charge density waves, which often result in anomalies in the electric transport properties. Here, we employ the ionic gating technique to realize a tunable, non-volatile organic ion intercalation in bulk single crystals of molybdenum disulphide (MoS). We demonstrate that this gate-driven organic ion intercalation induces a strong electron doping in the system without changing the pristine crystal symmetry and triggers the emergence of a re-entrant insulator-to-metal transition. We show that the gate-induced metallic state exhibits clear anomalies in the temperature dependence of the resistivity with a natural explanation as signatures of the development of a charge-density wave phase which was previously observed in alkali-intercalated MoS. The relatively large temperature at which the anomalies are observed (∼150 K), combined with the absence of any sign of doping-induced superconductivity down to ∼3 K, suggests that the two phases might be competing with each other to determine the electronic ground state of electron-doped MoS.

Comparison of Prospective and Retrospective Gated 4D Flow Cardiac MR Image Acquisitions in the Carotid Bifurcation.

To evaluate the agreement of 4D flow cMRI-derived bulk flow features and fluid (blood) velocities in the carotid bifurcation using prospective and retrospective gating techniques. Prospective and retrospective ECG-gated three-dimensional (3D) cine phase-contrast cardiac MRI with three-direction velocity encoding (i.e., 4D flow cMRI) data were acquired in ten carotid bifurcations from men (n = 3) and women (n = 2) that were cardiovascular disease-free. MRI sequence parameters were held constant across all scans except temporal resolution values differed. Velocity data were extracted from the fluid domain and evaluated across the entire volume or at defined anatomic planes (common, internal, external carotid arteries). Qualitative agreement between gating techniques was performed by visualizing flow streamlines and topographical images, and statistical comparisons between gating techniques were performed across the fluid volume and defined anatomic regions. Agreement in the kinematic data (e.g., bulk flow features and velocity data) were observed in the prospectively and retrospectively gated acquisitions. Voxel differences in time-averaged, peak systolic, and diastolic-averaged velocity magnitudes between gating techniques across all volunteers were 2.7%, 1.2%, and 6.4%, respectively. No significant differences in velocity magnitudes or components ([Formula: see text], [Formula: see text], [Formula: see text]) were observed. Importantly, retrospective acquisitions captured increased retrograde flow in the internal carotid artery (i.e., carotid sinus) compared to prospective acquisitions (10.4 ± 6.3% vs. 4.6 ± 5.3%; [Formula: see text] < 0.05). Prospective and retrospective ECG-gated 4D flow cMRI acquisitions provide comparable evaluations of fluid velocities, including velocity vector components, in the carotid bifurcation. However, the increased temporal coverage of retrospective acquisitions depicts increased retrograde flow patterns (i.e., disturbed flow) not captured by the prospective gating technique.

Multi-Institutional Experience With Preloaded Contralateral Gate of the Bifurcated Aortic Component During Endovascular Aortic Repair

Gate cannulation is typically the rate-limiting step during endovascular aortic repair (EVAR). The addition of a preloaded wire through the gate can make cannulation more efficient when challenges are anticipated. The aim of this study was to report a multi-institutional experience with the preloaded gate (PLG) technique during EVAR.

Electrical mapping of thermoelectric power factor in WO3 thin film

With growing environmental awareness and considerable research investment in energy saving, the concept of energy harvesting has become a central topic in the field of materials science. The thermoelectric energy conversion, which is a classic physical phenomenon, has emerged as an indispensable thermal management technology. In addition to conventional experimental investigations of thermoelectric materials, seeking promising materials or structures using computer-based approaches such as machine learning has been considered to accelerate research in recent years. However, the tremendous experimental efforts required to evaluate materials may hinder us from reaping the benefits of the fast-developing computer technology. In this study, an electrical mapping of the thermoelectric power factor is performed in a wide temperature-carrier density regime. An ionic gating technique is applied to an oxide semiconductor WO3, systematically controlling the carrier density to induce a transition from an insulating to a metallic state. Upon electrically scanning the thermoelectric properties, it is demonstrated that the thermoelectric performance of WO3 is optimized at a highly degenerate metallic state. This approach is convenient and applicable to a variety of materials, thus prompting the development of novel functional materials with desirable thermoelectric properties.

Efficient PPA Nano AES for IoT Applications

Abstract: Due to the fast-growing number of connected tiny devices to the Internet of Things (IoT), providing end-to-end security is vital. Therefore, it is essential to design the cryptosystem based on the requirement of resource constrained IoT devices. This article presents a lightweight advanced encryption standard (AES), a high-secure symmetric cryptography algorithm, implementation on field-programmable gate array (FPGA) and 65-nm technology for resource-constrained IoT devices. The proposed architecture includes 8-bit data path and five main blocks. We design two specified register banks, Key-Register and State-Register, for storing the plain text, keys, and intermediate data. To reduce the area, Shift-Rows is embedded inside the State-Register. To adapt the Mix-Column to 8-bit data path, we design an optimized 8-bit block for Mix-Columns with four internal registers, which accept 8-bit and send back 8-bit. Also, a shared optimized Sub-Bytes is employed for the key expansion phase and encryption phase. To optimize Sub-Bytes, we merge and simplify some parts of the Sub-Bytes. To reduce power consumption, we apply the clock gating technique to the design. Application-specific integrated circuit (ASIC) implementation results show a respective improvement in the area over the previous similar works from 35% to 2.4%. Based on the results, the proposed design is a suitable cryptosystem for tiny IoT devices. Keywords: IOT, Clock gating technique, ASIC

Analysis of diaphragm movements to specify geometric uncertainties of respiratory gating near end-exhalation for irradiation fields involving the liver dome

Background and PurposeThe technique of gating near end-exhalation is commonly adopted to reduce respiration-associated geometric uncertainties for particle beam therapy. However, for irradiation fields involving the liver dome, how diaphragm movements generating liver–lung interface change, alongside geometric uncertainties, remain unspecified. Methods and MaterialsPatients receiving respiratory-gated computed tomography (RGCT) with four-dimensional computed tomography (4DCT) scans during simulation were retrospectively reviewed. Differences (Δ) between RGCT and 4DCT images, including diaphragm displacements and liver–lung interface changes, were investigated to specify geometric uncertainties during early inhalation phases. Craniocaudal displacements (Δy, in sagittal/coronal planes) of diaphragm segments (dorsal/ventral/right lateral/medial), liver area changes (ΔA, in axial planes), and liver extent changes in specific directions of incidence (Δr, in axial planes) were analyzed. ResultsAltogether, 162 patients received simulating RGCT and 4DCT scans. In 22 of them, both images involved the liver dome. For most cases during early inhalation phases, the Δy values in the dorsal diaphragm were significantly greater than those in the ventral diaphragm (p < 0.05), the ΔA values were significantly enlarged with inhalation progressing (p < 0.05), and the Δr values in the dorsal direction were significantly larger than those in the ventral direction (p < 0.05). These results suggested that the dorsal diaphragm moves earlier and more in a caudal direction than the ventral diaphragm during early inhalation phases. ConclusionsFor respiratory-gated radiotherapy near end-exhalation and irradiation fields involving the liver dome, components of geometric uncertainties are temporospatial, including diaphragm segment movements, inhalation phases of irradiation, and beam angles of incidence.

A Novel Approach for the Detection of Every Significant Collapsing Bubble in Passive Cavitation Imaging.

Passive cavitation image (PCI) shows the power distribution of the acoustic emissions resulting from cavitation bubble collapses. The conventional PCI convolves the emitted cavitation signals with the point spread function of an imaging system, and it suffers from a low spatial resolution and contrast due to the increased sidelobe artifacts accumulated during the temporal integral process. To overcome the problems, the present study considers a 3-D time history of instantaneous PCIs where cavitation occurs at the local maxima of the main lobes of the beamformed cavitation field surrounded by the sidelobes largely spreading out in a time-space domain. A spatial and temporal gating technique was employed to detect the local maxima so that cavitation bubbles can be identified with their collapsing strength. The proposed approach was verified by the simulation for single and multiple cavitation bubbles, proving that it accurately detects the location and strength of the collapsing bubbles. An experimental test was also carried out for the cavitation bubbles produced by a clinical extracorporeal shock wave therapeutic device, which underpins that the proposed method successfully identifies every individual cavitation bubble.