scholarly journals Design and Analysis of a Light-Operated Microgripper Using an Opto-Electrostatic Repulsive Combined Actuator

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1026
Author(s):  
Jiahan Huang ◽  
Chengbin Jiang ◽  
Guanghui Li ◽  
Qinghua Lu ◽  
Haichu Chen
Keyword(s):  
Integrated Circuit ◽  
Critical Role ◽  
Dynamic Control ◽  
Response Speed ◽  
Effective Control ◽  
Driving Mechanism ◽  
Induced Voltage ◽  
External Interference ◽  
Numeric Calculation ◽  
Static Performance

The microgripper plays a critical role in micromanipulation systems; however, the handling accuracy of traditional driving microgrippers suffers from external vibration due to requiring connecting wires for an external power supply. By contrast, light driving has many advantages of remote non-contact manipulation, wireless energy transfer and no induced electromagnetic noise. In this study, an opto-electrostatic repulsive combined driving mechanism was proposed, and then a novel light-operated microgripper that used an opto-electrostatic repulsive actuator was designed and simulated. The static performance of the light-operated microgripper was investigated via simulation and numeric calculation results. The overall size of the microgripper was 1.3 mm × 0.7 mm × 1.027 mm, and the micro-objects ranging from 0 to 1000 μm in size could be manipulated and held using light. The proposed microgripper had many outstanding characteristics, such as a larger stroke, high response speed, remote non-contact manipulation, easy to integrate with an integrated circuit (IC) process and free from external interference. In addition, the dynamic control experiments of the photo-induced voltage of the PbLaZrTi (PLZT) ceramic were carried out, which shows that a stable electrical field could be obtained using the effective control methods that were developed.

scholarly journals A Novel Stick-Slip Nanopositioning Stage Integrated with a Flexure Hinge-Based Friction Force Adjusting Structure

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 765
Author(s):  
Junhui Zhu ◽  
Peng Pan ◽  
Yong Wang ◽  
Sen Gu ◽  
Rongan Zhai ◽  
...  
Keyword(s):  
Friction Force ◽  
High Speed ◽  
Simulation Analysis ◽  
Load Capacity ◽  
Dynamic Performance ◽  
Critical Role ◽  
Vertical Direction ◽  
Flexure Hinge ◽  
Stick Slip ◽  
Static Performance

The piezoelectrically-actuated stick-slip nanopositioning stage (PASSNS) has been applied extensively, and many designs of PASSNSs have been developed. The friction force between the stick-slip surfaces plays a critical role in successful movement of the stage, which influences the load capacity, dynamic performance, and positioning accuracy of the PASSNS. Toward solving the influence problems of friction force, this paper presents a novel stick-slip nanopositioning stage where the flexure hinge-based friction force adjusting unit was employed. Numerical analysis was conducted to estimate the static performance of the stage, a dynamic model was established, and simulation analysis was performed to study the dynamic performance of the stage. Further, a prototype was manufactured and a series of experiments were carried out to test the performance of the stage. The results show that the maximum forward and backward movement speeds of the stage are 1 and 0.7 mm/s, respectively, and the minimum forward and backward step displacements are approximately 11 and 12 nm, respectively. Compared to the step displacement under no working load, the forward and backward step displacements only increase by 6% and 8% with a working load of 20 g, respectively. And the load capacity of the PASSNS in the vertical direction is about 72 g. The experimental results confirm the feasibility of the proposed stage, and high accuracy, high speed, and good robustness to varying loads were achieved. These results demonstrate the great potential of the developed stage in many nanopositioning applications.

scholarly journals Stochastic approach to study control strategies of Covid-19 pandemic in India

2020 ◽  
Vol 148 ◽  
Author(s):  
Athokpam Langlen Chanu ◽  
R. K. Brojen Singh
Keyword(s):  
Control Strategies ◽  
Critical Role ◽  
Stochastic Approach ◽  
Effective Control ◽  
Demographic Stochasticity ◽  
Social Distancing ◽  
Exposed Population ◽  
Stochastic Framework ◽  
Simulation Results ◽  
Susceptible Populations

Abstract India is one of the severely affected countries by the Covid-19 pandemic at present. Within the stochastic framework of the SEQIR model, we studied publicly available data of the Covid-19 patients in India and analysed possible impacts of quarantine and social distancing as controlling strategies for the pandemic. Our stochastic simulation results clearly show that proper quarantine and social distancing should be maintained right from the start of the pandemic and continued until its end for effective control. This calls for a more disciplined social lifestyle in the future. However, only social distancing and quarantine of the exposed population are found not sufficient enough to end the pandemic in India. Therefore, implementation of other stringent policies like complete lockdown as well as increased testing of susceptible populations is necessary. The demographic stochasticity, which is quite visible in the system dynamics, has a critical role in regulating and controlling the pandemic.

scholarly journals The Dynamin-Like GTPase FgSey1 Plays a Critical Role in Fungal Development and Virulence in Fusarium graminearum

2020 ◽  
Vol 86 (11) ◽  
Author(s):  
Xuefa Chong ◽  
Chenyu Wang ◽  
Yao Wang ◽  
Yixiao Wang ◽  
Liyuan Zhang ◽  
...  
Keyword(s):  
Fusarium Graminearum ◽  
Vegetative Growth ◽  
Animal Feed ◽  
Pathogenic Fungus ◽  
Critical Role ◽  
Effective Control ◽  
Economic Losses ◽  
Head Blight ◽  
Fungal Development ◽  
Content Type

ABSTRACT Fusarium graminearum, the main pathogenic fungus causing Fusarium head blight (FHB), produces deoxynivalenol (DON), a key virulence factor, which is synthesized in the endoplasmic reticulum (ER). Sey1/atlastin, a dynamin-like GTPase protein, is known to be required for homotypic fusion of ER membranes, but the functions of this protein are unknown in pathogenic fungi. Here, we characterized Sey1/atlastin homologue FgSey1 in F. graminearum. Like Sey1/atlastin, FgSey1 is located in the ER. The FgSEY1 deletion mutant exhibited significantly reduced vegetative growth, asexual development, DON biosynthesis, and virulence. Moreover, the ΔFgsey1 mutant was impaired in the formation of normal lipid droplets (LDs) and toxisomes, both of which participate in DON biosynthesis. The GTPase, helix bundle (HB), transmembrane segment (TM), and cytosolic tail (CT) domains of FgSey1 are essential for its function, but only the TM domain is responsible for its localization. Furthermore, the mutants FgSey1K63A and FgSey1T87A lacked GTPase activity and failed to rescue the defects of the ΔFgsey1 mutant. Collectively, our data suggest that the dynamin-like GTPase protein FgSey1 affects the generation of LDs and toxisomes and is required for DON biosynthesis and pathogenesis in F. graminearum. IMPORTANCE Fusarium graminearum is a major plant pathogen that causes Fusarium head blight (FHB) of wheats worldwide. In addition to reducing the plant yield, F. graminearum infection of wheats also results in the production of deoxynivalenol (DON) mycotoxins, which are harmful to humans and animals and therefore cause great economic losses through pollution of food products and animal feed. At present, effective strategies for controlling FHB are not available. Therefore, understanding the regulation mechanisms of fungal development, pathogenesis, and DON biosynthesis is important for the development of effective control strategies of this disease. In this study, we demonstrated that a dynamin-like GTPase protein Sey1/atlastin homologue, FgSey1, is required for vegetative growth, DON production, and pathogenicity in F. graminearum. Our results provide novel information on critical roles of FgSey1 in fungal pathogenicity; therefore, FgSey1 could be a potential target for effective control of the disease caused by F. graminearum.

scholarly journals High Throughput Implementation of the Keccak Hash Function Using the Nios-II Processor

Technologies ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 15
Author(s):  
Argyrios Sideris ◽  
Theodora Sanida ◽  
Minas Dasygenis
Keyword(s):  
Integrated Circuit ◽  
Hash Function ◽  
High Speed ◽  
Critical Role ◽  
Optimization Techniques ◽  
Floating Point ◽  
Throughput Optimization ◽  
Nios Ii ◽  
Hash Algorithm ◽  
Hardware Description

Presently, cryptographic hash functions play a critical role in many applications, such as digital signature systems, security communications, protocols, and network security infrastructures. The new standard cryptographic hash function is Secure Hash Algorithm 3 (SHA-3), which is not vulnerable to attacks. The Keccak algorithm is the winner of the NIST competition for the adoption of the new standard SHA-3 hash algorithm. In this work, we present hardware throughput optimization techniques for the SHA-3 algorithm using the Very High Speed Integrated Circuit Hardware Description Language (VHDL) programming language for all output lengths in the Keccak hash function (224, 256, 384 and 512). Our experiments were performed with the Nios II processor on the FPGA Arria 10 GX (10AX115N2P45E1SG). We applied two architectures, one without custom instruction and one with floating point hardware 2. Finally, we compare the results with other existing similar designs and found that the proposed design with floating point 2 optimizes throughput (Gbps) compared to existing FPGA implementations.

scholarly journals Application of exogenous salicylic acid reduces disease severity of Plasmodiophora brassicae in pakchoi (Brassica campestris ssp. chinensis Makino)

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0248648
Author(s):  
Dandan Xi ◽  
Xiaofeng Li ◽  
Lu Gao ◽  
Zhaohui Zhang ◽  
Yuying Zhu ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Antioxidant Enzymes ◽  
Plant Growth ◽  
Disease Severity ◽  
Control Method ◽  
Plasmodiophora Brassicae ◽  
Critical Role ◽  
Membrane Lipid ◽  
Effective Control ◽  
Ros Scavenging

Clubroot is one of the most serious diseases affecting Brassicaceae plants worldwide. However, there is no effective control method for clubroot. Salicylic acid (SA) is a plant hormone that plays a critical role in plant defense. In our study, we found the disease severity of a clubroot-sensitive cultivar of pakchoi, Xinxiaqing, was reduced with 0.6mM exogenous SA after the infection of P. brassicae. To investigate the mechanism of SA-reduced disease severity against clubroot, then we analyzed the plant growth, alteration of antioxidant enzyme system, and related gene expression of Xinxiaqing. Results showed that the clubroot incidence rate and disease index were decreased after being treated with 0.6 mM exogenous SA. Furthermore, plant growth, reactive oxygen species (ROS) contents, and membrane lipid peroxidation were changed. The activities of antioxidant enzymes, including superoxide dismutase (SOD), ascorbic acid-peroxidase (APX), catalase (CAT), and glutathione reductase (GR), were increased. Additionally, the production rates of malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide anion (O2·–) were also inhibited. The expression levels of genes, encoding SOD, APX, CAT, and GR, were increased. By summering all results, we conclude that 0.6 mM SA contributes to the reduction of disease severity to clubroot by increasing the activities of antioxidant enzymes, abilities of osmotic regulation, and ROS scavenging to reduce the clubroot-induced damage in pakchoi.

scholarly journals Early beta oscillations in multisensory association areas underlie crossmodal performance enhancement

2021 ◽  
Author(s):  
Georgios Michail ◽  
Daniel Senkowski ◽  
Martin Holtkamp ◽  
Bettina Wächter ◽  
Julian Keil
Keyword(s):  
Performance Enhancement ◽  
Critical Role ◽  
Superior Temporal Gyrus ◽  
Response Speed ◽  
Auditory Information ◽  
Visual Responses ◽  
Beta Oscillations ◽  
Beta Power ◽  
Wide Range ◽  
Visual Areas

The combination of signals from different sensory modalities can enhance perception and facilitate behavioral responses. While previous research described crossmodal influences in a wide range of tasks, it remains unclear how such influences drive performance enhancements. In particular, the neural mechanisms underlying performance-relevant crossmodal influences, as well as the latency and spatial profile of such influences are not well understood. Here, we examined data from high-density electroencephalography (N = 30) and electrocorticography (N = 4) recordings to characterize the oscillatory signatures of crossmodal facilitation of response speed, as manifested in the speeding of visual responses by concurrent task-irrelevant auditory information. Using a data-driven analysis approach, we found that individual gains in response speed correlated with reduced beta power (13-25 Hz) in the audiovisual compared with the visual condition, starting within 80 ms after stimulus onset in multisensory association and secondary visual areas. In addition, the electrocorticography data revealed a beta power suppression in audiovisual compared with visual trials in the superior temporal gyrus (STG). Our data suggest that the crossmodal facilitation of response speed is associated with early beta power in multisensory association and secondary visual areas, presumably reflecting the enhancement of early sensory processing through selective attention. This finding furthers our understanding of the neural correlates underlying crossmodal response speed facilitation and highlights the critical role of beta oscillations in mediating behaviorally relevant audiovisual processing.

scholarly journals Fractal grid-induced turbulence strength characterization via piezoelectric thin-film flapping velocimetry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ted Sian Lee ◽  
Ean Hin Ooi ◽  
Wei Sea Chang ◽  
Ji Jinn Foo
Keyword(s):  
Thin Film ◽  
Large Scale ◽  
Mechanical Response ◽  
Critical Role ◽  
Low Frequency ◽  
Induced Voltage ◽  
Cross Sectional ◽  
Multiple Length Scales ◽  
Piezoelectric Thin Film ◽  
Turbulence Generation

AbstractThe centerline streamwise and cross-sectional (x/Dh = 0.425) turbulence characteristics of a 2D planar space-filling square-fractal-grid (SFG) composed of self-similar patterns superimposed at multiple length-scales is experimentally unveiled via piezoelectric thin-film flapping velocimetry (PTFV). The fluid–structure-interaction between a flexible piezoelectric thin-film and SFG-generated turbulent flow at ReDh = 4.1 × 104 is investigated by analysis of the thin-film’s mechanical response. Measurements of the thin-film-tip deflection δ and induced voltage V demonstrate increasing flow fluctuation strength in the turbulence generation region, followed by rapid decay further downstream of the SFG. Interestingly, SFG-induced turbulence enables the generation of maximum centerline thin-film’s response (Vrms, δrms) and millinewton turbulence-forcing (turbulence-induced excitation force acting on the thin-film) Frms which are respectively, 7× and 2× larger than the classical square-regular-grid of similar blockage ratio. The low frequency, large-scale energy-containing eddies at SFG’s central opening plays a critical role in driving the thin-film vibration. Most importantly, the SFG-generated turbulence at (y/T = 0.106, z/T = 0.125) away from the centerline allows equivalent mechanical characteristics of turbulence generation and decay, with peak of 1.9× nearer from grid. In short, PTFV provides a unique expression of the SFG-generated turbulence, of which, the equivalent turbulence length-scale and induced-forcing deduced could aid in deciphering the flow dynamics for effective turbulence management.

Techniques for Localization of IC Interconnection Defects

2002 ◽  
Vol 716 ◽  
Author(s):  
Edward I. Cole
Keyword(s):  
Integrated Circuit ◽  
Constant Current ◽  
Induced Voltage ◽  
Contrast Imaging ◽  
Thermally Induced ◽  
Imaging Results ◽  
Starting Point ◽  
Site Localization ◽  
Scanning Optical Microscopy ◽  
Failure Site

AbstractThe advances in integrated circuit technology has made failure site localization extremely challenging. Charge-Induced Voltage Alteration (CIVA), Low Energy CIVA (LECIVA), Light-Induced Voltage Alteration (LIVA), Seebeck Effect Imaging (SEI) and Thermally-Induced Voltage Alteration (TIVA) are five recently developed failure analysis techniques which meet the challenge by rapidly and non-destructively localizing interconnection defects on ICs. The techniques take advantage of voltage fluctuations in a constant current power supply as an electron or photon beam is scanned across an IC. CIVA and LECIVA are scanning electron microscopy (SEM) techniques that yield rapid localization of open interconnections. LIVA is a scanning optical microscopy (SOM) method that yields quick identification of damaged semiconductor junctions and determines transistor logic states. SEI and TIVA are SOM techniques that rapidly localize open interconnections and shorts respectively. LIVA, SEI, and TIVA can be performed from the backside of ICs by using the proper photon wavelength. CIVA, LECIVA, LIVA, TIVA, and SEI techniques in terms of the physics of signal generation, data acquisition system required, and imaging results displaying the utility of each technique for localizing interconnection defects. In addition to the techniques listed above, the Resistive Contrast Imaging (RCI) for localizing opens on metal test patterns will be described as a starting point for the “IVA” technologies.

Scanning Optical Microscopy Application in Micron® Memory Devices

2005 ◽  
Author(s):  
Wong Yaw Yuan ◽  
T.L. Edmund Poh ◽  
David Lam
Keyword(s):  
Failure Analysis ◽  
Integrated Circuit ◽  
Semiconductor Industry ◽  
Fault Isolation ◽  
Memory Devices ◽  
Back Side ◽  
Induced Voltage ◽  
Scanning Optical Microscopy ◽  
Side Emission ◽  
Complex Circuits

Abstract The migration to smaller geometries has translated to an increase in the number of transistors possible in each integrated circuit. Failure analysis of such complex circuits presents a major challenge to the semiconductor industry and is a driving force behind the considerable interest in nondestructive, cost-efficient, “shortcut” fault isolation techniques. In this paper, we present the application of thermal-induced voltage alteration (TIVA) for failure analysis of 0.11µm technology memory devices and demonstrate the key aspects of this technique. The back side TIVA results are compared with analysis performed using back side emission microscopy (EMMI), and the limitations of EMMI are highlighted. The advantages and limitations of the TIVA technique are also discussed.

Nonlinear Hierarchical MPC for Maximizing Aircraft Thermal Endurance

2020 ◽  
Author(s):  
Daniel D. Leister ◽  
Justin P. Koeln
Keyword(s):  
High Performance ◽  
Linear Models ◽  
Critical Role ◽  
Effective Control ◽  
Thermal Management System ◽  
Short And Long Term ◽  
Upper Level ◽  
Control Of Linear Systems ◽  
High Computational Efficiency

Abstract In modern high-performance aircraft, the Fuel Thermal Management System (FTMS) plays a critical role in the overall thermal energy management of the aircraft. Actuator and state constraints in the FTMS limit the thermal endurance and capabilities of the aircraft. Thus, an effective control strategy must plan and execute optimized transient fuel mass and temperature trajectories subject to these constraints over the entire course of operation. For the control of linear systems, hierarchical Model Predictive Control (MPC) has shown to be an effective approach to coordinating both short- and long-term system operation with reduced computational complexity. However, for controlling nonlinear systems, common approaches to system linearization may no longer be effective due to the long prediction horizons of upper-level controllers. This paper explores the limitations of using linear models for hierarchical MPC of the nonlinear FTMS found in aircraft. Numerical simulation results show that linearized models work well for lower-level controllers with short prediction horizons but lead to significant reductions in aircraft thermal endurance when used for upper-level controllers with long prediction horizons. Therefore, a mixed-linearity hierarchical MPC formulation is presented with a nonlinear upper-level controller and a linear lower-level controller to achieve both high performance and high computational efficiency.

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