Motion intention recognition is considered the key technology for enhancing the training effectiveness of upper limb rehabilitation robots for stroke patients,but traditional recognition systems are difficult to simul...Motion intention recognition is considered the key technology for enhancing the training effectiveness of upper limb rehabilitation robots for stroke patients,but traditional recognition systems are difficult to simultaneously balance real-time performance and reliability.To achieve real-time and accurate upper limb motion intention recognition,a multi-modal fusion method based on surface electromyography(sEMG)signals and arrayed flexible thin-film pressure(AFTFP)sensors was proposed.Through experimental tests on 10 healthy subjects(5 males and 5 females,age 23±2 years),sEMG signals and human-machine interaction force(HMIF)signals were collected during elbow flexion,extension,and shoulder internal and external rotation.The AFTFP signals based on dynamic calibration compensation and the sEMG signals were processed for feature extraction and fusion,and the recognition performance of single signals and fused signals was compared using a support vector machine(SVM).The experimental results showed that the sEMG signals consistently appeared 175±25 ms earlier than the HMIF signals(p<0.01,paired t-test).In offline conditions,the recognition accuracy of the fused signals exceeded 99.77%across different time windows.Under a 0.1 s time window,the real-time recognition accuracy of the fused signals was 14.1%higher than that of the single sEMG signal,and the system’s end-to-end delay was reduced to less than 100 ms.The AFTFP sensor is applied to motion intention recognition for the first time.And its low-cost,high-density array design provided an innovative solution for rehabilitation robots.The findings demonstrate that the AFTFP sensor adopted in this study effectively enhances intention recognition performance.The fusion of its output HMIF signals with sEMG signals combines the advantages of both modalities,enabling real-time and accurate motion intention recognition.This provides efficient command output for human-machine interaction in scenarios such as stroke rehabilitation.展开更多
Developing effective,versatile,and high-precision sensing interfaces remains a crucial challenge in human-machine-environment interaction applications.Despite progress in interaction-oriented sensing skins,limitations...Developing effective,versatile,and high-precision sensing interfaces remains a crucial challenge in human-machine-environment interaction applications.Despite progress in interaction-oriented sensing skins,limitations remain in unit-level reconfiguration,multiaxial force and motion sensing,and robust operation across dynamically changing or irregular surfaces.Herein,we develop a reconfigurable omnidirectional triboelectric whisker sensor array(RO-TWSA)comprising multiple sensing units that integrate a triboelectric whisker structure(TWS)with an untethered hydro-sealing vacuum sucker(UHSVS),enabling reversibly portable deployment and omnidirectional perception across diverse surfaces.Using a simple dual-triangular electrode layout paired with MXene/silicone nanocomposite dielectric layer,the sensor unit achieves precise omnidirectional force and motion sensing with a detection threshold as low as 0.024 N and an angular resolution of 5°,while the UHSVS provides reliable and reversible multi-surface anchoring for the sensor units by involving a newly designed hydrogel combining high mechanical robustness and superior water absorption.Extensive experiments demonstrate the effectiveness of RO-TWSA across various interactive scenarios,including teleoperation,tactile diagnostics,and robotic autonomous exploration.Overall,RO-TWSA presents a versatile and high-resolution tactile interface,offering new avenues for intelligent perception and interaction in complex real-world environments.展开更多
In this study,the design,analysis,manufacturing,and testing of a 3D-printed conformal microstrip array antenna for high-temperature environments is presented.3D printing technology is used to fabricate a curved cerami...In this study,the design,analysis,manufacturing,and testing of a 3D-printed conformal microstrip array antenna for high-temperature environments is presented.3D printing technology is used to fabricate a curved ceramic substrate,and laser sintering and microdroplet spraying processes are used to add the conductive metal on the curved substrate.The problems of gain loss,bandwidth reduction,and frequency shift caused by high temperatures are addressed by using a proper antenna design,with parasitic patches,slots,and metal resonant cavities.The antenna prototype is characterized by the curved substrates and the conductive metals for the power dividers,the patch,and the ground plane;its performance is examined up to a temperature of 600℃in a muffle furnace and compared with the results from the numerical analysis.The results show that the antenna can effectively function at 600℃and even higher temperatures.展开更多
A new technology for fabrication of silica on silicon arrayed waveguide grating (AWG) based on deep etching and thermal oxidation is presented.Using this method,a silicon layer is remained at the side of waveguide.The...A new technology for fabrication of silica on silicon arrayed waveguide grating (AWG) based on deep etching and thermal oxidation is presented.Using this method,a silicon layer is remained at the side of waveguide.The stress distribution and effective refractive index of waveguide fabricated by this approach are calculated using finite element and finite difference beam propagation method,respectively.The results of these studies indicate that the stress of silica on silicon optical waveguide can be matched in parallel and vertical direction and AWG polarization dependent wavelength (PDλ) can be reduced effectively due to side-silicon layer.展开更多
Magnesium alloys have narrow available slip result from close-packed hexagonal structure that limit their processing properties.In the recent work,the Mg-2Zn-0.46Y-0.5Nd,as materials for degradable stents,was applied ...Magnesium alloys have narrow available slip result from close-packed hexagonal structure that limit their processing properties.In the recent work,the Mg-2Zn-0.46Y-0.5Nd,as materials for degradable stents,was applied to produce as-extruded micro-tube with an outer diameter of 3.0mm and a wall thickness of 0.35mm by hot extrusion with an extrusion ratio of 105:1 at 653K and rapid cooling.The fine microstructure of the dynamic recrystallization of as-extruded micro-tube could be preserved by rapid cooling such as water-cooled,resulting in more excellent mechanical properties relative to air-cooled micro-tube.The addition of rare earth elements Y and Nd results in continuous dynamic recrystallization dominated the dynamic recrystallization mechanism.During the hot extrusion process,the activation of the non-basal slip system,especially the pyramidal(c+a)slip,could significantly weaken the texture strength,and the as-extruded micro-tube exhibits weak"RE"texture components(011^(-)1)||ED and(1^(-)21^(-)1)||ED.Hence,the magnesium alloy micro-tube prepared by the rapid cooling has fine microstructure and weak texture,which is favorable for further process and governance.展开更多
The present study reports an improved PCR-based technique that allows quick and effective screening of cDNA libraries. First, the cDNA library was arrayed as follow: about 3 X 10’ cDNA clones were multiplied as indiv...The present study reports an improved PCR-based technique that allows quick and effective screening of cDNA libraries. First, the cDNA library was arrayed as follow: about 3 X 10’ cDNA clones were multiplied as individual plaques on solid medium in 24-well culture dishes at 1 200 plaque forming units per well. The phage suspension of each well was transferred to an individual microcentrifuge tube in 72-tube box. Then, box pool, row pools and column pools were set up that respectively represent a 72-tube box, rows and columns within the box. To screen a specific target cDNA,primers specific for novel ESTs ob- tained in our laboratory were employed to conduct PCR in a hierarchy mode. PCR began with the box pools, resulting in the identification of some Positive box pools. Then PCR went down to the row and col- umn pools of the positive box. The intersection of the positive row (s) and column (s) revealed the candi- date positive tubes. The specificity of PCR products were meanwhile checked by restriction enzyme diges- tion. Finally, hybridization was carried out to get single specific cDNA clomes from the positive tubes. This PCR-based technique features high specificity, high efficiency and less-cost in large-scale cDNA library screening. Our initial implementation of the technique resulted in the isolation of three longer different cD- NA clones from a human fetal brain cDNA library. Thus this improved technique can serve as an alterna-tive to the time-consuming and laborious conventional hybridization-based method for screening cDNA li-brary.展开更多
We have provided optical simulations of the evanescently coupled waveguide photodiodes integrated with a 13- channels AWGs. The photodiode could exhibit high internal efficiency by appropriate choice of layers geometr...We have provided optical simulations of the evanescently coupled waveguide photodiodes integrated with a 13- channels AWGs. The photodiode could exhibit high internal efficiency by appropriate choice of layers geometry and refrac- tive index. Aseamless joint structure has been designed and fabricated for integrating the output waveguides of AWGs with the evanescently coupled waveguide photodiode array. The highest simulation quantum efficiency could achieve 92% when the matching layer thickfiess of the PD is 120 nm and the insertion length is 2 μm. The fabricated PD with 320-nm-thick match.ing layer and 2-μm-length insertion matching layer present a responsivity of 0.87 A/W.展开更多
A 32-channel wavelength division multiplexer with 100 GHz spacing is designed and fabricated by interleaving two silicon arrayed waveguide gratings(AWGs).It has a parallel structure consisting of two silicon 16-channe...A 32-channel wavelength division multiplexer with 100 GHz spacing is designed and fabricated by interleaving two silicon arrayed waveguide gratings(AWGs).It has a parallel structure consisting of two silicon 16-channel AWGs with200 GHz spacing and a Mach-Zehnder interferometer(MZI)with 200 GHz free spectral range.The 16 channels of one silicon AWG are interleaved with those of the other AWG in spectrum,but with an identical spacing of 200 GHz.For the composed wavelength division multiplexer,the experiment results reveal 32 wavelength channels in C-band,a wavelength spacing of 100 GHz,and a channel crosstalk lower than-15 dB.展开更多
In this letter,a fiber Bragg grating(FBG)dynamic strain sensing system using a semiconductor optical amplifier(SOA)-fiber ring laser(FRL)and an arrayed waveguide grating(AWG)demodulator is proposed.Due to the characte...In this letter,a fiber Bragg grating(FBG)dynamic strain sensing system using a semiconductor optical amplifier(SOA)-fiber ring laser(FRL)and an arrayed waveguide grating(AWG)demodulator is proposed.Due to the characteristics of SOA,it can act as the gain medium as well as light source.The AWG module is used as the wavelength demodulator.It is shown that SOA-based FRL sensors can accurately respond to 1.5μεdynamic strain signal with high frequency up to 120 k Hz and almost no distortion in the waveforms.Experimental results show that the system can be used for acoustic testing,such as underwater ultrasonic detection and external impact monitoring.In addition,the simultaneous dual-channel demodulated system is investigated in detail to verify the multiplexing.This dynamic strain sensing system can be widely utilized in structural health monitoring because of its high stability,low cost and good multiplexability.展开更多
In this paper,the densely arrayed bonded particle model is proposed for simulation of granular materials with discrete element method(DEM)considering particle crushing.This model can solve the problem of pore calculat...In this paper,the densely arrayed bonded particle model is proposed for simulation of granular materials with discrete element method(DEM)considering particle crushing.This model can solve the problem of pore calculation after the grains are crushed,and reduce the producing time of specimen.In this work,several one-dimensional compressing simulations are carried out to investigate the effect of particle crushing on mechanical properties of granular materials under a wide range of stress.The results show that the crushing process of granular materials can be divided into four different stages according to er-logσy curves.At the end of the second stage,there exists a yield point,after which the physical and mechanical properties of specimens will change significantly.Under extremely high stress,particle crushing will wipe some initial information of specimens,and specimens with different initial gradings and void ratios present some similar characteristics.Particle crushing has great influence on grading,lateral pressure coefficient and compressibility of granular materials,and introduce extra irreversible volume deformation,which is necessary to be considered in modelling of granular materials in wide stress range.展开更多
The operation principle of an arrayed waveguide grating(AWG) multiplexer is introduced and the 4×4 AWG with following design parameters is discussed in detail, such as the choice of wavelength, the neighboring ar...The operation principle of an arrayed waveguide grating(AWG) multiplexer is introduced and the 4×4 AWG with following design parameters is discussed in detail, such as the choice of wavelength, the neighboring arrayed waveguide distance ΔL, the channel frequency interval Δf, and the free spectral range. The structure of 4×4 AWG is designed and the result of stimulated test is also given. Analysis shows that the 4×4 AWG is characterized by a wide dynamic range, low crosstalk, better spectrum properties, and a compact structure.展开更多
In this paper,an arrayed liquid prisms system based on electrowetting-on-dielectric(EWOD)is proposed to modulate the three-dimensional beam steering control.The relationships between beam steering control range,electr...In this paper,an arrayed liquid prisms system based on electrowetting-on-dielectric(EWOD)is proposed to modulate the three-dimensional beam steering control.The relationships between beam steering control range,electrowetting contact angle,and liquid refractive index are derived.COMSOL is employed to demonstrate the beam steering control properties of the electrowetting-based arrayed liquid prisms when bias voltages are applied.The influence of contact angle,liquid refractive index,and interval between adjacent prisms are discussed.The results show that the beam steering control performance of the system will be greatly improved,and the range of beam steering angle is−20°to 20°by selecting optimum combinations of liquids and rational interval between adjacent prisms.The arrayed liquid prisms system can succeed to achieve continuous control of beam steering in a conical region with an apex angle of 40°,and the vertex of the circular cone is located at the 15.02 mm in the z-axis.The proposed system will promote the development of non-mechanical beam steering technology and have a wide range of applications.展开更多
The improved performance of a wavelength-tunable arrayed waveguide grating (AWG) is demonstrated, including the crosstalk, insertion loss and the wavelength tuning efficiency. A reduced impact of the fabrication proce...The improved performance of a wavelength-tunable arrayed waveguide grating (AWG) is demonstrated, including the crosstalk, insertion loss and the wavelength tuning efficiency. A reduced impact of the fabrication process on the AWG is achieved by the design of bi-level tapers. The wavelength tuning of the AWG is achieved according to the thermo-optic effect of silicon, and uniform heating of the silicon waveguide layer is achieved by optimizing the heater design. The fabricated AWG shows a minimum crosstalk of 16 dB, a maximum insertion loss of 3.91 dB and a wavelength tuning efficiency of 8.92 nm/W, exhibiting a ～8 dB improvement of crosstalk, ～2.1 dB improvement of insertion loss and ～5 nm/W improvement of wavelength tuning efficiency, compared to our previous reported results.展开更多
A 13-channel, InP-based arrayed waveguide grating （AWG） is designed and fabricated in which the on-chip loss of the central channel is about -5 dB and the crosstalk is less than -23 dB in the center of the spectrum ...A 13-channel, InP-based arrayed waveguide grating （AWG） is designed and fabricated in which the on-chip loss of the central channel is about -5 dB and the crosstalk is less than -23 dB in the center of the spectrum response. However, the central wavelength and channel spacing are deviated from the design values. To improve their accuracy, an optimized design is adopted to compensate the process error. As a result, the central wavelength 1549.9 nm and channel spacing 1.59 nm are obtained in the experiment, while their design values are 1549.32 nm and 1.6 nm, respectively. The route capability and thermo-optic characteristic of the AWG are also discussed in detail.展开更多
The fact that the signal results in signal―crosstalk is confirmed forarrayed―waveguide grating as NXN optical router, and the relation between the crosstalk and powerpenalty is obtained. The method reveals the rando...The fact that the signal results in signal―crosstalk is confirmed forarrayed―waveguide grating as NXN optical router, and the relation between the crosstalk and powerpenalty is obtained. The method reveals the random distributions of optical path phase errors in twomultiplexers with channel numbers of 10 and 160. It is shown that the crosstalk must be less than―28 dB for a power penalty below 1 dB at a bit error rate of 1X10^(-9). It is found that when N =100, crosstalk power value is ? 20 dB with compensation power of 2―3 dB, so the compensation poweris not ignored.展开更多
A cross-linkable fluorinated poly (ether ether ketone) (FPEEK) was synthesized for the fabrication of arrayed waveguide grating (AWG) multiplexer. The results of thermal gravimetric analysis (TGA) and near-infrared ab...A cross-linkable fluorinated poly (ether ether ketone) (FPEEK) was synthesized for the fabrication of arrayed waveguide grating (AWG) multiplexer. The results of thermal gravimetric analysis (TGA) and near-infrared absorption spectrum show that the materials have high thermal stability and high optical transparency in the infrared communication region. The refractive index of FPEEK can be controlled easily by changing the fluorine content of the materials. The 32-channel AWG multiplexer is fabricated using the FPEEK and oxygen reactive ion etching technology. The AWG multiplexer exhibits that the insertion loss is from 12.8 to 17.8 dB and the channel crosstalk is less than-20 dB. The wavelength channel spacing and the center wavelength are 0.8nm and 1548nm, respectively.展开更多
It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be...It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be solved.A method of 3D structural color turning on periodic metasurfaces fabricated by the microlens array and self-assembly technology was proposed in this study.In the experiment,Polydimethylsiloxane(PDMS)flexible film was used as a substrate,and SiO2 microspheres were scraped into grooves of the PDMS film to form 3D photonic crystal structures.By adjusting the number of blade-coated times and microsphere concentrations,high-saturation structural color micropatterns were obtained.These films were then matched with microlens arrays to produce dynamic graphics with iridescent effects.The results showed that by blade-coated two times and SiO2 microsphere concentrations of 50%are the best conditions.This method demonstrates the potential for being widely applied in the anticounterfeiting printing and ultra-high-resolution display.展开更多
A four-channel 400 GHz channel spacing InP-based arrayed waveguide grating with a flattened wavelength re- sponse by employing a multimode interference coupler at the input waveguide of the filter is prepared. The fab...A four-channel 400 GHz channel spacing InP-based arrayed waveguide grating with a flattened wavelength re- sponse by employing a multimode interference coupler at the input waveguide of the filter is prepared. The fabricated devices show a flattened spectral response with a broadened 3-dB bandwidth up to 3.5 nm, interchan- nel non-uniformity of 〈0. 7dB and excellent match to the simulation results.展开更多
The near infrared (NIR) fluorescence enhancement by local surface plasmon resonanoce from arrayed gold (Au) nanoblocks was investigated by NIR fluorescent dyes, IR780, immobilized in hydrophobic DNA thin film on glass...The near infrared (NIR) fluorescence enhancement by local surface plasmon resonanoce from arrayed gold (Au) nanoblocks was investigated by NIR fluorescent dyes, IR780, immobilized in hydrophobic DNA thin film on glass substrates, to clarify the gap mode effect on the fluorescence enhancement. In the substrate with Dimer type Au nanoblock arrangement, average total fluorescence intensity was larger by 10.0, 2.4, and 12.4 times for non-polarized, P- and S- polarization as compared with that on a glass substrate alone, respectively. These findings suggested that enhancement of excitation light intensity at nanogap in the Dimer type Au nanoblock arrangement affected the fluorescence intensity. Average total fluorescence intensity, on the other hand, was smaller by 0.63 times as compared with that on a glass substrate alone in the checkerboard type Au array. It is suggested that the fluorescence quenching was caused by the energy transfer from the excited state of IR780 to Au nanoblocks or by the increased deactivation of excited dye molecules induced by resonance with Au nanoblocks at the checkerboard arrangement. We have firstly achieved the NIR fluorescence enhancement by LSPR due to the gap mode.展开更多
The integrated optical true time delay phased array antenna system has the advantages of high bandwidth,small size,low loss and strong antiinterference capability,etc.The high integration of the optically controlled p...The integrated optical true time delay phased array antenna system has the advantages of high bandwidth,small size,low loss and strong antiinterference capability,etc.The high integration of the optically controlled phased array antenna system is a necessary trend for the future development of the phased array,and it is also a major focus and difficulty in the current research of integrated microwave photonics.This paper firstly introduces the basic principle and development history of optical true time delay phased array antenna system based on microwave photonics,and briefly introduces the main implementation methods and integration platform of optical true time delay.Then,the application and development prospect of optical true time delay technology in beam control of phased array antenna system are mainly presented.Finally,according to the current research progress,the possible research directions of integrated optically controlled phased array antenna systems in the future are proposed.展开更多
基金supported by Guangdong Basic and Applied Basic Research Foundation(No.2024A1515012810).
文摘Motion intention recognition is considered the key technology for enhancing the training effectiveness of upper limb rehabilitation robots for stroke patients,but traditional recognition systems are difficult to simultaneously balance real-time performance and reliability.To achieve real-time and accurate upper limb motion intention recognition,a multi-modal fusion method based on surface electromyography(sEMG)signals and arrayed flexible thin-film pressure(AFTFP)sensors was proposed.Through experimental tests on 10 healthy subjects(5 males and 5 females,age 23±2 years),sEMG signals and human-machine interaction force(HMIF)signals were collected during elbow flexion,extension,and shoulder internal and external rotation.The AFTFP signals based on dynamic calibration compensation and the sEMG signals were processed for feature extraction and fusion,and the recognition performance of single signals and fused signals was compared using a support vector machine(SVM).The experimental results showed that the sEMG signals consistently appeared 175±25 ms earlier than the HMIF signals(p<0.01,paired t-test).In offline conditions,the recognition accuracy of the fused signals exceeded 99.77%across different time windows.Under a 0.1 s time window,the real-time recognition accuracy of the fused signals was 14.1%higher than that of the single sEMG signal,and the system’s end-to-end delay was reduced to less than 100 ms.The AFTFP sensor is applied to motion intention recognition for the first time.And its low-cost,high-density array design provided an innovative solution for rehabilitation robots.The findings demonstrate that the AFTFP sensor adopted in this study effectively enhances intention recognition performance.The fusion of its output HMIF signals with sEMG signals combines the advantages of both modalities,enabling real-time and accurate motion intention recognition.This provides efficient command output for human-machine interaction in scenarios such as stroke rehabilitation.
基金supported by the National Natural Science Foundation of China(General Program)under Grant 52571385National Key R&D Program of China(Grant No.2024YFC2815000 and No.2024YFB3816000)+12 种基金Open Fund of State Key Laboratory of Deep-sea Manned Vehicles(Grant No.2025SKLDMV07)Shenzhen Science and Technology Program(WDZC20231128114452001,JCYJ20240813112107010 and JCYJ20240813111910014)the Tsinghua SIGS Scientific Research Startup Fund(QD2022021C)the Dreams Foundation of Jianghuai Advance Technology Center(2023-ZM 01 Z006)the Ocean Decade International Cooperation Center(ODCC)(GHZZ3702840002024020000026)Shenzhen Key Laboratory of Advanced Technology for Marine Ecology(ZDSYS20230626091459009)Shenzhen Science and Technology Program(No.KJZD20240903100905008)the National Natural Science Foundation of China(No.22305141)Pearl River Talent Program(No.2023QN10C114)General Program of Guangdong Province(No.2025A1515011700)the Guangdong Innovative and Entrepreneurial Research Team Program(2023ZT10C040)Scientific Research Foundation from Shenzhen Finance Bureau(No.GJHZ20240218113600002)Tsinghua University(JC2023001).
文摘Developing effective,versatile,and high-precision sensing interfaces remains a crucial challenge in human-machine-environment interaction applications.Despite progress in interaction-oriented sensing skins,limitations remain in unit-level reconfiguration,multiaxial force and motion sensing,and robust operation across dynamically changing or irregular surfaces.Herein,we develop a reconfigurable omnidirectional triboelectric whisker sensor array(RO-TWSA)comprising multiple sensing units that integrate a triboelectric whisker structure(TWS)with an untethered hydro-sealing vacuum sucker(UHSVS),enabling reversibly portable deployment and omnidirectional perception across diverse surfaces.Using a simple dual-triangular electrode layout paired with MXene/silicone nanocomposite dielectric layer,the sensor unit achieves precise omnidirectional force and motion sensing with a detection threshold as low as 0.024 N and an angular resolution of 5°,while the UHSVS provides reliable and reversible multi-surface anchoring for the sensor units by involving a newly designed hydrogel combining high mechanical robustness and superior water absorption.Extensive experiments demonstrate the effectiveness of RO-TWSA across various interactive scenarios,including teleoperation,tactile diagnostics,and robotic autonomous exploration.Overall,RO-TWSA presents a versatile and high-resolution tactile interface,offering new avenues for intelligent perception and interaction in complex real-world environments.
基金National Natural Science Foundation of china(No.U2241205)the Natural Science Basic Research Program of Shaanxi(Nos.2022JC-33,2023-GHZD-35,and 2024JC-ZDXM-25)+1 种基金the Fundamental Research Funds for the Central Universitiesthe National 111 Project to provide fund for conducting experiments。
文摘In this study,the design,analysis,manufacturing,and testing of a 3D-printed conformal microstrip array antenna for high-temperature environments is presented.3D printing technology is used to fabricate a curved ceramic substrate,and laser sintering and microdroplet spraying processes are used to add the conductive metal on the curved substrate.The problems of gain loss,bandwidth reduction,and frequency shift caused by high temperatures are addressed by using a proper antenna design,with parasitic patches,slots,and metal resonant cavities.The antenna prototype is characterized by the curved substrates and the conductive metals for the power dividers,the patch,and the ground plane;its performance is examined up to a temperature of 600℃in a muffle furnace and compared with the results from the numerical analysis.The results show that the antenna can effectively function at 600℃and even higher temperatures.
文摘A new technology for fabrication of silica on silicon arrayed waveguide grating (AWG) based on deep etching and thermal oxidation is presented.Using this method,a silicon layer is remained at the side of waveguide.The stress distribution and effective refractive index of waveguide fabricated by this approach are calculated using finite element and finite difference beam propagation method,respectively.The results of these studies indicate that the stress of silica on silicon optical waveguide can be matched in parallel and vertical direction and AWG polarization dependent wavelength (PDλ) can be reduced effectively due to side-silicon layer.
基金The authors are grateful for the financial support of Key Projects of the Joint Fund of the National Natural Science Foundation of China(U1804251)the National Key Research and Development Program of China(2018YFC1106703,2017YFB0702504 and 2016YFC1102403).
文摘Magnesium alloys have narrow available slip result from close-packed hexagonal structure that limit their processing properties.In the recent work,the Mg-2Zn-0.46Y-0.5Nd,as materials for degradable stents,was applied to produce as-extruded micro-tube with an outer diameter of 3.0mm and a wall thickness of 0.35mm by hot extrusion with an extrusion ratio of 105:1 at 653K and rapid cooling.The fine microstructure of the dynamic recrystallization of as-extruded micro-tube could be preserved by rapid cooling such as water-cooled,resulting in more excellent mechanical properties relative to air-cooled micro-tube.The addition of rare earth elements Y and Nd results in continuous dynamic recrystallization dominated the dynamic recrystallization mechanism.During the hot extrusion process,the activation of the non-basal slip system,especially the pyramidal(c+a)slip,could significantly weaken the texture strength,and the as-extruded micro-tube exhibits weak"RE"texture components(011^(-)1)||ED and(1^(-)21^(-)1)||ED.Hence,the magnesium alloy micro-tube prepared by the rapid cooling has fine microstructure and weak texture,which is favorable for further process and governance.
基金National Natural Science Fund!(39392900 ) 863 High-tech Project Fund of China!(102-10-03-02 )
文摘The present study reports an improved PCR-based technique that allows quick and effective screening of cDNA libraries. First, the cDNA library was arrayed as follow: about 3 X 10’ cDNA clones were multiplied as individual plaques on solid medium in 24-well culture dishes at 1 200 plaque forming units per well. The phage suspension of each well was transferred to an individual microcentrifuge tube in 72-tube box. Then, box pool, row pools and column pools were set up that respectively represent a 72-tube box, rows and columns within the box. To screen a specific target cDNA,primers specific for novel ESTs ob- tained in our laboratory were employed to conduct PCR in a hierarchy mode. PCR began with the box pools, resulting in the identification of some Positive box pools. Then PCR went down to the row and col- umn pools of the positive box. The intersection of the positive row (s) and column (s) revealed the candi- date positive tubes. The specificity of PCR products were meanwhile checked by restriction enzyme diges- tion. Finally, hybridization was carried out to get single specific cDNA clomes from the positive tubes. This PCR-based technique features high specificity, high efficiency and less-cost in large-scale cDNA library screening. Our initial implementation of the technique resulted in the isolation of three longer different cD- NA clones from a human fetal brain cDNA library. Thus this improved technique can serve as an alterna-tive to the time-consuming and laborious conventional hybridization-based method for screening cDNA li-brary.
基金Project supported by the National High Technology Research and Development Program of China(Grant Nos.2013AA031401,2015AA016902,and 2015AA016904)the National Natural Science Foundation of China(Grant Nos.61176053,61274069,and 61435002)the National Basic Research Program of China(Grant Nos.2012CB933503 and 2013CB932904)
文摘We have provided optical simulations of the evanescently coupled waveguide photodiodes integrated with a 13- channels AWGs. The photodiode could exhibit high internal efficiency by appropriate choice of layers geometry and refrac- tive index. Aseamless joint structure has been designed and fabricated for integrating the output waveguides of AWGs with the evanescently coupled waveguide photodiode array. The highest simulation quantum efficiency could achieve 92% when the matching layer thickfiess of the PD is 120 nm and the insertion length is 2 μm. The fabricated PD with 320-nm-thick match.ing layer and 2-μm-length insertion matching layer present a responsivity of 0.87 A/W.
基金Project supported by the National Key Research and Development Program of China(Grant No.2019YFB2203600)。
文摘A 32-channel wavelength division multiplexer with 100 GHz spacing is designed and fabricated by interleaving two silicon arrayed waveguide gratings(AWGs).It has a parallel structure consisting of two silicon 16-channel AWGs with200 GHz spacing and a Mach-Zehnder interferometer(MZI)with 200 GHz free spectral range.The 16 channels of one silicon AWG are interleaved with those of the other AWG in spectrum,but with an identical spacing of 200 GHz.For the composed wavelength division multiplexer,the experiment results reveal 32 wavelength channels in C-band,a wavelength spacing of 100 GHz,and a channel crosstalk lower than-15 dB.
基金supported by the National Natural Science Foundation of China(No.51874064)the Project of Graduate Innovation in Chongqing University of Technology(No.gzlcx20223295)。
文摘In this letter,a fiber Bragg grating(FBG)dynamic strain sensing system using a semiconductor optical amplifier(SOA)-fiber ring laser(FRL)and an arrayed waveguide grating(AWG)demodulator is proposed.Due to the characteristics of SOA,it can act as the gain medium as well as light source.The AWG module is used as the wavelength demodulator.It is shown that SOA-based FRL sensors can accurately respond to 1.5μεdynamic strain signal with high frequency up to 120 k Hz and almost no distortion in the waveforms.Experimental results show that the system can be used for acoustic testing,such as underwater ultrasonic detection and external impact monitoring.In addition,the simultaneous dual-channel demodulated system is investigated in detail to verify the multiplexing.This dynamic strain sensing system can be widely utilized in structural health monitoring because of its high stability,low cost and good multiplexability.
基金The authors wish to thank the National Natural Science Foundation of China(No.11772117)the Fundamental Research Funds for the Central Universities(No.2015B37414)+1 种基金Henan Scientific and Technical Project under Grant(No.192102310480)Key Scientific Research Project of Colleges and Universities in Henan Province(CN)(21B560015)for financial support.
文摘In this paper,the densely arrayed bonded particle model is proposed for simulation of granular materials with discrete element method(DEM)considering particle crushing.This model can solve the problem of pore calculation after the grains are crushed,and reduce the producing time of specimen.In this work,several one-dimensional compressing simulations are carried out to investigate the effect of particle crushing on mechanical properties of granular materials under a wide range of stress.The results show that the crushing process of granular materials can be divided into four different stages according to er-logσy curves.At the end of the second stage,there exists a yield point,after which the physical and mechanical properties of specimens will change significantly.Under extremely high stress,particle crushing will wipe some initial information of specimens,and specimens with different initial gradings and void ratios present some similar characteristics.Particle crushing has great influence on grading,lateral pressure coefficient and compressibility of granular materials,and introduce extra irreversible volume deformation,which is necessary to be considered in modelling of granular materials in wide stress range.
文摘The operation principle of an arrayed waveguide grating(AWG) multiplexer is introduced and the 4×4 AWG with following design parameters is discussed in detail, such as the choice of wavelength, the neighboring arrayed waveguide distance ΔL, the channel frequency interval Δf, and the free spectral range. The structure of 4×4 AWG is designed and the result of stimulated test is also given. Analysis shows that the 4×4 AWG is characterized by a wide dynamic range, low crosstalk, better spectrum properties, and a compact structure.
基金This work has been supported by the National Natural Science Foundation of China(No.61775102)the Youth Program of National Natural Science Foundation of China(No.61905117)+1 种基金the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX19_0970)the Technology Foundation of Basic Enhancement Program(No.2019_JCJQ_JJ_446).
文摘In this paper,an arrayed liquid prisms system based on electrowetting-on-dielectric(EWOD)is proposed to modulate the three-dimensional beam steering control.The relationships between beam steering control range,electrowetting contact angle,and liquid refractive index are derived.COMSOL is employed to demonstrate the beam steering control properties of the electrowetting-based arrayed liquid prisms when bias voltages are applied.The influence of contact angle,liquid refractive index,and interval between adjacent prisms are discussed.The results show that the beam steering control performance of the system will be greatly improved,and the range of beam steering angle is−20°to 20°by selecting optimum combinations of liquids and rational interval between adjacent prisms.The arrayed liquid prisms system can succeed to achieve continuous control of beam steering in a conical region with an apex angle of 40°,and the vertex of the circular cone is located at the 15.02 mm in the z-axis.The proposed system will promote the development of non-mechanical beam steering technology and have a wide range of applications.
基金Supported by the National Key R&D Program of China under Grant No 2016YFB0402504
文摘The improved performance of a wavelength-tunable arrayed waveguide grating (AWG) is demonstrated, including the crosstalk, insertion loss and the wavelength tuning efficiency. A reduced impact of the fabrication process on the AWG is achieved by the design of bi-level tapers. The wavelength tuning of the AWG is achieved according to the thermo-optic effect of silicon, and uniform heating of the silicon waveguide layer is achieved by optimizing the heater design. The fabricated AWG shows a minimum crosstalk of 16 dB, a maximum insertion loss of 3.91 dB and a wavelength tuning efficiency of 8.92 nm/W, exhibiting a ～8 dB improvement of crosstalk, ～2.1 dB improvement of insertion loss and ～5 nm/W improvement of wavelength tuning efficiency, compared to our previous reported results.
基金Project supported by the National High Technology Research and Development Program of China(Grant Nos.2011AA010303 and 2013AA031401)the National Natural Science Foundation of China(Grant No.61090390)
文摘A 13-channel, InP-based arrayed waveguide grating （AWG） is designed and fabricated in which the on-chip loss of the central channel is about -5 dB and the crosstalk is less than -23 dB in the center of the spectrum response. However, the central wavelength and channel spacing are deviated from the design values. To improve their accuracy, an optimized design is adopted to compensate the process error. As a result, the central wavelength 1549.9 nm and channel spacing 1.59 nm are obtained in the experiment, while their design values are 1549.32 nm and 1.6 nm, respectively. The route capability and thermo-optic characteristic of the AWG are also discussed in detail.
文摘The fact that the signal results in signal―crosstalk is confirmed forarrayed―waveguide grating as NXN optical router, and the relation between the crosstalk and powerpenalty is obtained. The method reveals the random distributions of optical path phase errors in twomultiplexers with channel numbers of 10 and 160. It is shown that the crosstalk must be less than―28 dB for a power penalty below 1 dB at a bit error rate of 1X10^(-9). It is found that when N =100, crosstalk power value is ? 20 dB with compensation power of 2―3 dB, so the compensation poweris not ignored.
文摘A cross-linkable fluorinated poly (ether ether ketone) (FPEEK) was synthesized for the fabrication of arrayed waveguide grating (AWG) multiplexer. The results of thermal gravimetric analysis (TGA) and near-infrared absorption spectrum show that the materials have high thermal stability and high optical transparency in the infrared communication region. The refractive index of FPEEK can be controlled easily by changing the fluorine content of the materials. The 32-channel AWG multiplexer is fabricated using the FPEEK and oxygen reactive ion etching technology. The AWG multiplexer exhibits that the insertion loss is from 12.8 to 17.8 dB and the channel crosstalk is less than-20 dB. The wavelength channel spacing and the center wavelength are 0.8nm and 1548nm, respectively.
文摘It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be solved.A method of 3D structural color turning on periodic metasurfaces fabricated by the microlens array and self-assembly technology was proposed in this study.In the experiment,Polydimethylsiloxane(PDMS)flexible film was used as a substrate,and SiO2 microspheres were scraped into grooves of the PDMS film to form 3D photonic crystal structures.By adjusting the number of blade-coated times and microsphere concentrations,high-saturation structural color micropatterns were obtained.These films were then matched with microlens arrays to produce dynamic graphics with iridescent effects.The results showed that by blade-coated two times and SiO2 microsphere concentrations of 50%are the best conditions.This method demonstrates the potential for being widely applied in the anticounterfeiting printing and ultra-high-resolution display.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61274046,61201103,61335009 and61320106013the National Basic Research Program of China under Grant No 2013AA014202
文摘A four-channel 400 GHz channel spacing InP-based arrayed waveguide grating with a flattened wavelength re- sponse by employing a multimode interference coupler at the input waveguide of the filter is prepared. The fabricated devices show a flattened spectral response with a broadened 3-dB bandwidth up to 3.5 nm, interchan- nel non-uniformity of 〈0. 7dB and excellent match to the simulation results.
文摘The near infrared (NIR) fluorescence enhancement by local surface plasmon resonanoce from arrayed gold (Au) nanoblocks was investigated by NIR fluorescent dyes, IR780, immobilized in hydrophobic DNA thin film on glass substrates, to clarify the gap mode effect on the fluorescence enhancement. In the substrate with Dimer type Au nanoblock arrangement, average total fluorescence intensity was larger by 10.0, 2.4, and 12.4 times for non-polarized, P- and S- polarization as compared with that on a glass substrate alone, respectively. These findings suggested that enhancement of excitation light intensity at nanogap in the Dimer type Au nanoblock arrangement affected the fluorescence intensity. Average total fluorescence intensity, on the other hand, was smaller by 0.63 times as compared with that on a glass substrate alone in the checkerboard type Au array. It is suggested that the fluorescence quenching was caused by the energy transfer from the excited state of IR780 to Au nanoblocks or by the increased deactivation of excited dye molecules induced by resonance with Au nanoblocks at the checkerboard arrangement. We have firstly achieved the NIR fluorescence enhancement by LSPR due to the gap mode.
基金supported by Fund of State Key Laboratory of IPOC(BUPT)(No.IPOC2021ZT16),China.
文摘The integrated optical true time delay phased array antenna system has the advantages of high bandwidth,small size,low loss and strong antiinterference capability,etc.The high integration of the optically controlled phased array antenna system is a necessary trend for the future development of the phased array,and it is also a major focus and difficulty in the current research of integrated microwave photonics.This paper firstly introduces the basic principle and development history of optical true time delay phased array antenna system based on microwave photonics,and briefly introduces the main implementation methods and integration platform of optical true time delay.Then,the application and development prospect of optical true time delay technology in beam control of phased array antenna system are mainly presented.Finally,according to the current research progress,the possible research directions of integrated optically controlled phased array antenna systems in the future are proposed.
