Refresh Time Research Articles

10‐3: Distinguished Paper: Reducing Resolution Loss in Naked Eye 3D Display Using Dual Ferroelectric Liquid Crystal (FLC) Shutters for Time‐multiplexed Light Field Display

Usually, the resolution loss is serious in light field display due to the spatial multiplexing of several neighboring pixels to display images from different directions. With the limitation in the resolution of the flat panel display, the light field 3D display shows insufficient display size, image depth, or resolution. This article utilized the FLC with a fast response at 2 kHz and the optimized charge compensation method to achieve a high refresh time multiplexing method, which can effectively increase the display resolution by up to 32 times and is very promising for light field 3D displays in the future.

High-speed fluidic processing circuits for dynamic control of haptic and robotic systems.

Fluidic logic circuits simplify system design for soft robotics by eliminating bulky components while enabling operation in a range of hostile environments that are incompatible with electronics but at the expense of limited computational capabilities and response times on the order of seconds. This paper presents a four-terminal fluidic transistor optimized for fast switching times, reduced component count, low unit cost, and high reproducibility to achieve complex fluidic control circuits while maintaining flow rates of liters per minute. A ring oscillator using three fluidic transistors achieves oscillation frequencies up to a kilohertz with full signal propagation, tolerating billions of cycles without failure. Fundamental processor circuits like a full adder and a 3-bit analog-to-digital converter require just seven transistors each. A decode circuit drives a high-resolution soft haptic display with refresh times below the human perception threshold for latency, and an electronics-free control circuit performs closed-loop position control of a pneumatic actuator with disturbance rejection, demonstrating the value across domains.

Organic Synaptic Transistors with an Ultra‐Short‐Term Weight‐Reconstruction for Processing Multiple Types of Signals

AbstractAn organic synaptic transistor (OST) that utilizes a multiple‐annealing process and an ion gate to achieve significant reductions in operating voltage and increases in transconductance is demonstrated. The OST exhibits an ultra‐short‐term plasticity (USTP) with a maximum retention time of only 20.7 ms, which does not increase with the number and duration of spikes. This is the shortest retention time yet achieved by an ion‐gel‐regulated synaptic transistor. In addition, OST‐integrated array exhibits a tunable weight plasticity and a short weight refresh time for a stable image resetting in ample time of <0.2 s. It is also sensitive to the frequency and amplitude of electrical inputs; a low‐frequency suppression and a nonlinear amplitude gain enables OST‐constructed filter for use in processing multiple types of signals. This work is a step toward constructing high‐performance and multifunctional artificial intelligent systems.

Sourdough powder: physicochemical, microbiological properties and shelf-life stability in different package type.

This study aims to optimize the culture condition of semi-liquid sourdough using Kombucha as a starter culture and to evaluate the physicochemical properties, microbial viability and recovering ability of sourdough powder when packaged in different types of packaging for 120days. Optimal maturation time (103.47h) and maximum leavening rate (1.27mL/h) of sourdough were achieved at an incubation temperature of 34°C and interval refreshment time at 7h. The optimized culture was spray-dried using 3% Arabic gum (w/v) as a carrier agent yielding 35.86% powder with acceptable viability of 8.71 log CFU/g lactic acid bacteria and 9.03CFU/g yeast. The sourdough powder was packed in four packaging (LDPE, vacuumed LDPE, aluminum foil laminated pouch and vacuumed aluminum foil laminated pouch) and exhibited comparable physicochemical properties during 120days of storage. The viability of both lactic acid bacteria and yeast count in sourdough powder when packed in vacuumed aluminum foil laminated pouch showed higher stability for 90days (6.18 log CFU/g and 6.82 log CFU/g) but reduced to below detection limit after 120days (5.54 and 5.94 log CFU/g). This suggested that Kombucha sourdough powder packed in vacuumed aluminum laminated pouch could be stored for up to 90days.

Forced ignition modeling of methane-ethylene mixtures in scramjet combustors

To propose a design guideline for a scramjet combustor at low cost, an ignition model for a scramjet combustor is required. Therefore, the overall aim of this study was to propose an ignition model that could be used to estimate the forced ignition limits within a cavity. In this study, we developed two forced ignition models (FIMs): the forced ignition model in the recirculating zone (FIMR) and the forced ignition model in the shear layer (FIMS). We evaluated the forced ignition limits using a micro-rocket torch within a scramjet combustor. The validated results of the FIMs indicated that the modified FIMR incorporating cavity refresh time (defined as the time required for complete replacement of all gases in the cavity) was the most appropriate method for calculating the forced ignition limit within the recirculation zone. However, in the case of Φ2.0 + 50 % He torch, the modified FIMR could not precisely estimate the forced ignition limit, showing that further modification to the present prediction model was necessary. The forced ignition process in the cavity was investigated using OH* chemiluminescence images, which indicated that the fuel mixture ignited in the shear layer; therefore, it was necessary to investigate ignition not only within the recirculation zone but also in the shear layer. In the case of Φ2.0 + 50 % He torch, the forced ignition limit could not be predicted by the FIMR, but it could be predicted by the FIMS. These results demonstrate that the FIMS provides improved prediction accuracy for the forced ignition limit in the scramjet combustors.

Effect of Refresh Time on XeF2 Gas-assisted FIB Milling of GaAs

Focused ion beam (FIB) machining can be used to fabricate gallium arsenide-based devices, which have a surface finish of several nanometers, and the FIB machining speed and surface finish can be greatly improved using xenon difluoride (XeF2) gas-assisted etching. Although the refresh time is one of the most important parameters in the gas-assisted etching process, its effect on the machining quality of the surface finish has rarely been studied. Therefore, in this work, we investigated the effect of the refresh time on the etching process, including the dissociation process of XeF2, the refresh time dependency of the sputter in yield under different incident angles, and the surface finish under different refresh times. The results revealed that a selective etching mechanism occurred at different refresh times. At an incidence angle of 0°, the sputtering yield increased with the refresh time and reached its maximum value at 500 ms; at an incidence angle of 30°, the sputtering yield reached its minimum value at a refresh time of 500 ms. For surface roughness, the incident angle played a more important role than the refresh time. The surface finish was slightly better at an incidence angle of 30° than at 0°. In addition, both F and Xe elements were detected in the processed area: Xe elements were evenly distributed throughout the processing area, while F elements tended to accumulate in the whole processing area. The results suggest that the optimum surface can be obtained when a larger refresh time is employed.

Fast artifact filtering algorithm for electrical resistivity tomography

Owing to the ill-conditioned nature of electrical resistivity tomography and the measurement error of the hardware equipment, the reconstructed resistivity distribution image often contains artifacts of varying degrees. Other soft-field imaging technologies, such as electrical impedance tomography and electrical capacitance tomography, also encounter artifacts. Artifacts interfere with the assessment of damaged areas. To eliminate the influence of artifacts on the reconstructed image, a novel artifact elimination algorithm called the fast artifact filtering (FAF) algorithm is proposed. Based on the calculation results of existing algorithms, such as the Newton’s one-step error reconstructor (NOSER) algorithm, the FAF algorithm can remove the damaged areas with low confidence from the potentially damaged areas and only retain the damaged areas with high confidence for final imaging. Several simulation models were used to test the effectiveness of the artifact elimination algorithm proposed in this study. The test results show that the number of artifacts in the final reconstructed image is significantly reduced after the NOSER algorithm is combined with the FAF algorithm. In addition, when the number of finite element model division elements was 4802, the refresh time of a single image increased by approximately 1 ms. A structural health monitoring test for hollow structure is provided. The results show that the FAF also performs well on the measured voltage data.

Experimental and numerical investigation of a self-supplementing dual-cavity plasma synthetic jet actuator

The primary issue regarding the plasma synthetic jet actuator (PSJA) is its performance attenuation at high frequencies. To solve this issue, a self-supplementing, dual-cavity, plasma synthetic jet actuator (SD-PSJA) is designed, and the static properties of the SD-PSJA are investigated through experiments and numerical simulations. The pressure measurement shows that the SD-PSJA has two saturation frequencies (1200 Hz and 2100 Hz), and the experimental results show that both the saturation frequencies decrease as the volume of the bottom cavity of the SD-PSJA increases. As the size of the supplement hole increases, the first saturation frequency increases continuously, while the second saturation frequency shows a trend of first decreasing and then increasing. Numerical simulations show that the working process of the SD-PSJA is similar to that of the PSJA, but the volume of the cavity in the SD-PSJA is smaller than that of the PSJA; the SD-PSJA can supplement air to the top cavity through two holes, thus reducing the refresh time and effectively improving the jet intensity of the actuator at high frequencies.

Fowler–Nordheim Stress-Induced Degradation of Buried-Channel-Array Transistors in DRAM Cell for Cryogenic Memory Applications

The degradation of the fin-type buried-channel-array transistor (BCAT) in dynamic random access memory (DRAM) cell is investigated under Fowler–Nordheim stress at various temperatures, including 77 K. While the increase in the OFF current is dominated by the Shockley–Read–Hall junction leakage, the threshold voltage shift ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\Delta } {V}_{T}$ </tex-math></inline-formula> ) comprises a positive component due to the interface trap generation and a negative component resulting from the electric field concentration-induced charge trapping into the gate insulator bulk, with respective activation energies of 0.22 and 0.13 eV. Furthermore, based on the consistency between the experimentally decomposed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\Delta } {V}_{T}$ </tex-math></inline-formula> components and the simulated ones, it is found that the anode hole injection dominates the degradations of the wordline-active operation and refresh time in cryogenic DRAM.

Fast dual-comb spectroscopy based on a dual-wavelength all-fiber ring laser with high repetition rate

We demonstrate fast dual-comb spectroscopy based on a high-repetition-rate dual-wavelength erbium-doped fiber laser with a large repetition rate difference. It can operate in three different dual-wavelength states with repetition rate differences of 4.32, 2.74 and 3.635 kHz, respectively. To the best of our knowledge, the corresponding refresh time can be as low as 231 μs, which is the fastest in dual-comb spectroscopy using a single fundamentally mode-locked all-fiber laser. The high repetition rate of approximately 154.68 MHz provides a maximum optical frequency bandwidth of 4.37 THz. Dual-comb spectroscopy was used to measure the transmittance curve of the Fabry–Perot etalon.

Multi-gate BCAT Structure and Select Word-line Driver in DRAM for Reduction of GIDL

In this article, we evaluate gate induced drain leakage that affects the refresh time of buried cell array transistor DRAM cells. We proposed a multi-gate BCAT structure to minimize gate induced drain leakage and modified the select word-line circuit to operate multi-gate buried cell array transistor by adding only one PMOS. In the multi-gate structure, by changing the gate voltage, the work function of the metal gate was adjusted to effectively mitigate the electric field formed in the drain region by approximately four orders. As an adopting multi-gate structure, band to band tunneling is suppressed and gate induced drain leakage current is reduced. We verified that the dual-gate structure had less leakage current than the poly-Si BCAT using the TCAD simulation. The reduction of leakage according to the number of gates is inferred by confirming the reduction in GIDL of the three-gate structure compared with the dual-gate structure. Furthermore, the SPICE simulation confirmed that the proposed select word-line circuit transmits different optimized voltages to multiple gates when it is off than while transferring the same voltage when on. This structure can also be extended for application to other DRAM structures, such as the vertical structure and 3D-stacked DRAMs.

Temperature Estimation of HBM2 Channels with Tail Distribution of Retention Errors in FPGA-HBM2 Platform

High-bandwidth memory 2 (HBM2) vertically stacks multiple dynamic random-access memory (DRAM) dies to achieve a small form factor and high capacity. However, it is difficult to diagnose HBM2 issues owing to their structural complexity and 2.5D integration with heterogeneous chips. The effects of the temperature at the base logic die (TL), and the refresh interval at the stacked DRAM dies, were experimentally investigated by counting the dynamic retention errors in the eight channels in an HBM2. TL was indirectly controlled by the heatsink temperature (TS). The lognormal distribution represents the distribution of the cell counts with varying refresh times. All Z-magnitudes (multiples of the distribution standard deviation) over the various refresh cycle times (RCTs) up to 2.045 s in a single channel at TL of 70 °C appeared below 4.4, which means that the error bits belong to the tail distribution. The Z-differences in the eight channels were distinctively larger than the Z-differences of the same channels at a constant temperature, demonstrating that the temperature difference in the stacked dies resulted in larger Z-differences. The largest Z-difference was 0.091 for all the channels at an RCT of 1.406 s, which was approximately 4.82 times smaller than the Z-difference between the TL temperatures of 70 °C and 80 °C in a single channel. The Z-difference between the TL temperatures of 70 °C and 72 °C in a single channel was approximately the same as the Z-difference in all the channels at an RCT of 2.045 s.

Application of Image Processing Variation Model Based on Network Control Robot Image Transmission and Processing System in Multimedia Enhancement Technology

The rapid development of the information age brings convenience to human life, but it also brings great challenges to information processing technology. Multimedia enhancement technology is an organic combination of multimedia technology and information processing technology, and it is also an important way of modern multimedia image information processing. However, its usefulness and effectiveness are increasingly negatively affected by the open information environment. The processing effect is also unable to meet the development requirements of the visual field. In order to improve this problem, this paper studied the image transmission and processing system of network-controlled robot on the basis of analyzing the characteristics of the problems existing in the current stage of multimedia technology. On this basis, a new image processing variational model was established and applied to multimedia enhancement technology, which improved the efficiency and effect of image information processing. Finally, the feasibility of its application function and performance was tested by experiments. The test results showed that in the difficult mode of the image processing task, the refresh time of the model in this paper in the multimedia enhancement technology was 1.13 s in total, which was not much different from the test results in the easy mode. Also, in the load stress test, the comprehensive test values under full-function operation and partial-function operation were 42.04% and 20.92%, respectively. Compared with the traditional model, the model in this paper has stronger carrying capacity in multimedia enhancement technology and has better processing ability and stability.

Computing the Similarity Estimate Using Approximate Memory

In many computing applications there is a need to compute the similarity of sets of elements. When the sets have many elements or comparison involves many sets, computing the similarity requires significant computational effort and storage capacity. As in most cases, a reasonably accurate estimate is sufficient, many algorithms for similarity estimation have been proposed during the last decades. Those algorithms compute signatures for the sets and use them to estimate similarity. However, as the number of sets that need to be compared grows, even these similarity estimation algorithms require significant memory with its associated power dissipation. This article for the first time considers the use of approximate memories for similarity estimation. A theoretical analysis and simulation results are provided; initially it is shown that similarity sketches can tolerate large bit error rates and thus, they can benefit from using approximate memories without substantially compromising the accuracy of the similarity estimate. An understanding of the effect of errors in the stored signatures on the similarity estimate is pursued. A scheme to mitigate the impact of errors is presented; the proposed scheme tolerates even larger bit error rates and does not need additional memory. For example, bit error rates of up to <inline-formula><tex-math notation="LaTeX">$10^{-4}$</tex-math></inline-formula> have less than a 1% impact on the accuracy of the estimate when the memory is unprotected, and larger bit errors rates can be tolerated if the memory is parity protected. These findings can be used for voltage supply scaling and increasing the refresh time in SRAMs and DRAMs. Based on those initial results, an enhanced implementation is further proposed for unprotected memories that further extends the range of tolerated BERs and enables power savings of up to 61.31% for SRAMs. In conclusion, this article shows that the use of approximate memories in sketches for similarity estimation provides significant benefits with a negligible impact on accuracy.

Multi‐objective approach to forecast design refresh time due to COTS obsolescence

AbstractThe purpose of this study is to provide program managers and systems engineers with a novel algorithm in determining the design refresh time (DRT) of sustainment‐dominated systems due to COTS obsolescence. Most of the research done so far has focused on cost optimization. The main contribution of the study is two‐fold. First, besides cost optimization, we have introduced efficiency optimization within a balanced approach to determine the DRT, under multiple objectives. Second, we used a set‐based approach over the hypervolume quality values of solutions rather than population‐based Pareto solutions. We proposed a discrete‐time simulation model by using Multi‐Objective Evolutionary Algorithms where the deterioration over the quality values of Pareto solution sets is used as an indicator for a DRT. We supported the proposed mathematical model in theory with empirical findings from a case study for a sustainment‐dominated Naval Command and Control System that was designed in 2004 and deployed in 2007. We ran the simulation as for 2007 and conducted an analysis over the cost and operational efficiency objectives to compare the situation experienced in real life against the simulation outputs of the proposed model. The results revealed that not only the total life cycle cost but also efficient operational sustainability of a system would be increased significantly if the system had gone through design refreshes as proposed by the model. We showed that the deterioration of the Pareto optimal solutions’ hypervolume quality values over time is an effective marker to decide the optimal DRT under conflicting multiple objectives.

Sub-femtometer-resolution absolute spectroscopy with sweeping electro-optic combs

Optical frequency comb with evenly spaced lines over a broad bandwidth has revolutionized the fields of optical metrology and spectroscopy. Here, we propose a fast interleaved dual-comb spectroscopy with sub-femtometer-resolution and absolute frequency, in which two electro-optic frequency combs are swept. Electrically-modulated stabilized laser enables ultrahigh resolution of 0.16 fm (or 20 kHz in optical frequency) and single-shot measurement in 90 ms. Total 20 million points are recorded spanning 3.2 nm (or 400 GHz) bandwidth, corresponding to a spectral sampling rate of 2.5 × 10⁸ points/s under Nyquist-limitation. Besides, considering the trade-off between the measurement time and spectral resolution, a fast single-shot measurement is also realized in 1.6 ms with 8 fm (or 1 MHz) resolution. We demonstrate the 25-averaged result with 30.6 dB spectral measurement signal-to-noise ratio (SNR) by reducing the filter bandwidth in demodulation. The results show great prospect for precise measurement with flexibly fast refresh time, high spectral resolution, and high SNR.

Parametric study of high-frequency characteristics of plasma synthetic jet actuator

A major issue of plasma synthetic jet actuator (PSJA) is the severe performance deterioration at high working frequency. In this study, experiments and numerical simulation are combined together to investigate the influence of thermal conductivity, throat length (L th) and discharge duration (T d) on the high-frequency characteristics of PSJA. Results show that the variation of the actuator thermal conductivity and discharge duration will not alter the saturation frequency of the actuator, whereas decreasing the throat length results in an increase of the saturation frequency. For a short-duration capacitive discharge of 1.7 μs, a clear shock wave is issued from the orifice, followed by a weak jet. As a comparison, when the discharge duration is increased up to 202.6 μs, a strong jet column is formed and no obvious shock wave can be visualized. Based on numerical simulation results, it becomes clear that the long-duration pulse-DC discharge is able to heat the cavity gas to a much higher temperature (3141 K) than capacitive discharge, greatly improving the conversion efficiency of the arc discharge energy to the internal energy of the cavity gas. In addition, high-speed Schlieren imaging is deployed to study the performance degradation mechanism of PSJA at high working frequency. Monitor of the exit jet grayscale indicates that as long as the saturation frequency is exceeded, the actuator becomes unstable due to insufficient refresh time. The higher the discharge frequency, the more frequently the phenomenon of ‘misfires’ will occur, which explains well the decaying jet total pressure at above saturation frequency.

Simultaneous scattering compensation at multiple points in multi-photon microscopy.

The two-photon fluorescence imaging depth has been significantly improved in recent years by compensating for tissue scattering with wavefront correction. However, in most approaches the wavefront corrections are valid only over a small sample region on the order of 1 to 10 µm. In samples where most scattering structures are confined to a single plane, sample conjugate correction geometries can increase the observable field to a few tens of µm. Here, we apply a recently introduced fast converging scheme for sensor-less scattering correction termed “Dynamic Adaptive Scattering compensation Holography” (DASH) in a sample conjugate configuration with a high pixel count nematic liquid crystal spatial light modulator (LC-SLM). Using a large SLM allows us to simultaneously correct for scattering at multiple field points, which can be distributed over the entire field of view provided by the objective lens. Despite the comparably slow refresh time of LC-SLMs, we achieve correction times on the order of 10 s per field point, which we show is sufficiently fast to counteract scattering at multiple sites in living mouse hippocampal tissue slices.

DyTAN: Dynamic Ternary Content Addressable Memory Using Nanoelectromechanical Relays

Ternary content addressable memory (TCAM) is one type of associative memory and has been widely used in caches, routers, and many other mapping-aware applications. While the conventional SRAM-based TCAM is high speed and bulky, there have been denser but slower and less reliable nonvolatile TCAMs using nonvolatile memory (NVM) devices. Meanwhile, some CMOS TCAMs using dynamic memories have been also proposed. Although dynamic TCAM could be denser than the 16T SRAM TCAM and more reliable than the nonvolatile TCAMs, CMOS dynamic TCAMs still suffer from the row-by-row refresh energy and time overheads. In this article, we propose dynamic TCAM using nanoelectromechanical (NEM) relays (DyTAN), and utilize one-shot refresh (OSR) to solve the memory refresh problem. By exploiting the unique NEM relay characteristics, DyTAN outperforms the existing works in the balance between density, speed, and power efficiency. Compared with the 16T SRAM-based TCAM, the 5T CMOS dynamic TCAM, the 2T2R TCAM, and the 2FeFET TCAM, evaluations show that the proposed DyTAN reduces the write energy by up to $2.3\times $ , $1.3\times $ , $131\times $ , and $13.5\times $ , and improves the search energy-delay-product (EDP) by up to $12.7\times $ , $1.7\times $ , $1.3\times $ , and $2.8\times $ , respectively.

Research on LED multi-sector stable display model in variable rotational speed

To solve the display distortion caused by the motor rotational speed changes in the long-term operation of the rotating LED multi-sector display system, the model for LED multi-sector stable display (MSSD) in variable rotational speed is proposed based on the principle of visual persistence. The stepping motor subdivision driving technology is applied to the rotating LED multi-sector display, and the equal precision frequency measurement method is used for accurate rotational speed measurement. Then the innovation adaptive kalman filter (IAKF) is researched to further enhance the robustness to eliminate noise pollution, and the relationship between the modification value caused by rotational speed and the LED linear array minimum refresh time is analysed. The rotating LED MSSD system based on LED linear array rotated by stepping motor is provided. The test results reveal the relationship between rotational speed and the LED linear array minimum refresh time, and show that the lighting position of the LED can be synchronized with the lighting state during the rotational speed fluctuation, and the error can be controlled to a low level via LED linear array minimum refresh time correction. The designed model can effectively eliminate the distortion of the rotating LED multi-sector display screen caused by the changes of the motor rotational speed, and has a very stable display effect.