Comprehensive evaluation factor of optoelectronic properties for transparent conductive metallic mesh films

Finding the optimal optoelectronic properties(zero-order optical transmittance,shielding effectiveness,and stray light uniformity)of metallic mesh is significant for its application in electromagnetic interference shielding areas.However,there are few relevant studies at present.Based on optoelectronic properties,we propose a comprehensive evaluation factor Q,which is simple in form and can be used to evaluate the mesh with different parameters in a simple and efficient way.The effectivity of Q is verified by comparing the trend of Q values with the evaluation results of the technique for order preference by similarity to ideal solution(TOPSIS).The evaluation factor Q can also be extended to evaluate the optoelectronic properties of different kinds of metallic meshes,which makes it extremely favorable for metallic mesh design and application.

Design of Microstructure Parameters on a Small Multi-Throttle Aerostatic Guideway in Photolithography

A compact multi-throttle aerostatic guideway is the preferred structure for high precision and acceleration motion in the variable-slit system(VS)of photolithography.The presence of microstructure,such as recesses and grooves,on the guideway working surface has been found to improve the loading performance.Nevertheless,the effects on the guideway performance of changing the microstructure on the micron level are not yet clear.The mesh adaptation method,which was proposed by the authors,is employed in this paper to quantitatively study the influences of four microstructure parameters.The effect of tuning these parameters on the loading performance is revealed.The level of impact determines the proposed design process of the parameters.The characteristic feature of the proposed design process is that the working points of carrying capacity,stiffness,and rotational stiffness are unified under twoway adjusting by means of recess parameters.According to the proposed design process and tuning method,the restriction of supply pressure is lifted to a certain extent and the mutual tradeoff among the loading performances is relieved.The experimental results show that the rotational stiffness of the designed guideway,based on the tuned parameters,reached 2.14×10^(4) Nmrad1 and increased by 69.8%.In a scanning test of the applied VS on argon fluoride laser(ArF)photolithography,the average scanning acceleration reached 67.5 m·s^(-2),meeting the design specification.

Finite-Time Stabilization of Linear Systems With Input Constraints by Event-Triggered Control

Dear editor,This letter designs the event-triggered control(ETC)to achieve finite-time stabilization(FTS)of linear systems with input constraints.The key idea of the established algorithm is that the designed time-varying high-gain is only scheduled on a specified time determined by an event-triggered mechanism.

Resilient Event-Triggered Model Predictive Control for Adaptive Cruise Control Under Sensor Attacks

Dear Editor,This letter addresses the resilient model predictive control(MPC)problems for adaptive cruise control(ACC)systems under sensor attacks.In the light of vulnerabilities of ACC systems to sensor attacks,an intrusion detection mechanism is proposed at the controller side to distinguish abnormal data.Then,the robust control gains are derived to design the terminal region constraint for MPC.

Displacement measuring grating interferometer: a review

A grating interferometer, called the "optical encoder," is a commonly used tool for precise displacement measurements. In contrast to a laser interferometer, a grating interferometer is insensitive to the air refractive index and can be easily applied to multi-degree-of-freedom measurements, which has made it an extensively researched and widely used device. Classified based on the measuring principle and optical configuration, a grating interferometer experiences three distinct stages of development: homodyne, heterodyne, and spatially separated heterodyne. Compared with the former two, the spatially separated heterodyne grating interferometer could achieve a better resolution with a feature of eliminating periodic nonlinear errors. Meanwhile, numerous structures of grating interferometers with a high optical fold factor, a large measurement range, good usability, and multidegree-of-freedom measurements have been investigated. The development of incremental displacement measuring grating interferometers achieved in recent years is summarized in detail, and studies on error analysis of a grating interferometer are briefly introduced.

CdS quantum dot sensitized p-type NiO as photocathode with integrated cobaloxime in photoelectrochemical cell for water splitting

CdS sensitized NiO electrode was used as the photoactive cathode in a photoelectrochemical cell for water splitting,avoiding the use of a sacrificial electron donor.Photocurrent increment under visible light irradiation was observed after integration of[Co（dmgH）_2（4-Me-py）Cl]（1） to the photocathode,suggesting 1 could accept electrons from photoexcited CdS for water reduction and NiO could move the holes in the valence band of CdS to anode for water oxidation.

Effect of asymmetrical transfer coefficients of a non-polarizing beam splitter on the nonlinear error of the polarization interferometer

The mechanism of a non-polarizing beam splitter (NPBS) with asymmetrical transfer coefficients causing the rotation of polarization direction is explained in principle, and the measurement nonlinear error caused by NPBS is analyzed based on Jones matrix theory. Theoretical calculations show that the nonlinear error changes periodically, and the error period and peak values increase with the deviation between transmissivities of p-polarization and s-polarization states. When the transmissivity of p-polarization is 53% and that of s-polarization is 48%, the maximum error reaches 2.7 nm. The imperfection of NPBS is one of the main error sources in simultaneous phase-shifting polarization interferometer, and its influence can not be neglected in the nanoscale ultra-precision measurement.

An adjustable anti-resonance frequency controller for a dual-stage actuation semi-active vibration isolation system

In the semiconductor manufacturing industry,the dynamic model of a controlled object is usually obtained from a frequency sweeping method before motion control.However,the existing isolators cannot properly isolate the disturbance of the inertial force on the platform base during frequency sweeping(the frequency is between 0 Hz and the natural frequency).In this paper,an adjustable anti-resonance frequency controller for a dual-stage actuation semi-active vibration isolation system(DSASAVIS)is proposed.This system has a significant anti-resonance characteristic;that is,the vibration amplitude can drop to nearly zero at a particular frequency,which is called the anti-resonance frequency.The proposed controller is designed to add an adjustable anti-resonance frequency to fully use this unique anti-resonance characteristic.Experimental results show that the closed-loop transmissibility is less than−15 dB from 0 Hz to the initial anti-resonance frequency.Furthermore,it is less than−30 dB around an added anti-resonance frequency which can be adjusted from 0 Hz to the initial anti-resonance frequency by changing the parameters of the proposed controller.With the proposed controller,the disturbance amplitude of the payload decays from 4 to 0.5 mm/s with a reduction of 87.5%for the impulse disturbance applied to the platform base.Simultaneously,the system can adjust the anti-resonance frequency point in real time by tracking the frequency sweeping disturbances,and a good vibration isolation performance is achieved.This indicates that the DSA-SAVIS and the proposed controller can be applied in the guarantee of an ultra-low vibration environment,especially at frequency sweeping in the semiconductor manufacturing industry.

Fused-like angles:replacement for roll-pitch-yaw angles for a six-degree-of-freedom grating interferometer

Representation of orientation is important in a six-degree-of-freedom grating interferometer but only a few studies have focused on this topic.Roll-pitch-yaw angles,widely used in aviation,navigation,and robotics,are now being brought to the field of multi-degree-of-freedom interferometric measurement.However,the roll-pitch-yaw angles are not the exact definitions the metrologists expected in interferometry,because they require a certain sequential order of rotations and may cause errors in describing complicated rotations.The errors increase as the tip and tilt angles of the grating increase.Therefore,a replacement based on fused angles in robotics is proposed and named“fused-like angles.”The fused-like angles are error-free,so they are more in line with the definitions in grating interferometry and more suitable for six-degree-of-freedom measurements.Fused-like angles have already been used in research on the kinematic model and decoupling algorithm of the six-degree-of-freedom grating interferometer.