Smart actuators and wearable and implantable devices have attracted much attention in healthcare and environmental sensing.Flexible electronic and ionic materials are the two main approaches used to construct these de...Smart actuators and wearable and implantable devices have attracted much attention in healthcare and environmental sensing.Flexible electronic and ionic materials are the two main approaches used to construct these devices.Among them,hydrogel-based ionic materials offer unique advantages,such as biocompatibility and adaptable mechanical properties.However,ionic hydrogels encounter challenges in achieving wirelessly powered and noncontact sensing.To address this,we introduce MXene nanosheets to construct ionotronic hydrogels.Leveraging the rich surface charges and electronic conductivity of MXene nanosheets,ionotronic hydrogels can harvest vibrational and electromagnetic waves as electrical energy and enable noncontact sensing.Under ultrasound,it can continuously generate voltages up to 85 V and light up lightemitting diodes,promising wireless charging of implanted devices.In addition,it achieves an absorption coefficient of 0.2 for 915 MHz electromagnetic waves,enabling noncontact sensing through radio frequency identification.Notably,the physically crosslinked network of the MXenebased hydrogels maintained structural and performance stability under ultrasonic stimulation and exhibited self-healing properties.Even when cut into two halves,the self-healing hydrogel fully regenerates its original performance.This study provides insight into the development of ionotronic hydrogels for wirelessly powered and noncontact sensing in smart actuators and wearable and implantable applications.展开更多
In the past decade,the global industry and research attentions on intelligent skin-like electronics have boosted their applications in diverse fields including human healthcare,Internet of Things,human–machine interf...In the past decade,the global industry and research attentions on intelligent skin-like electronics have boosted their applications in diverse fields including human healthcare,Internet of Things,human–machine interfaces,artificial intelligence and soft robotics.Among them,flexible humidity sensors play a vital role in noncontact measurements relying on the unique property of rapid response to humidity change.This work presents an overview of recent advances in flexible humidity sensors using various active functional materials for contactless monitoring.Four categories of humidity sensors are highlighted based on resistive,capacitive,impedance-type and voltage-type working mechanisms.Furthermore,typical strategies including chemical doping,structural design and Joule heating are introduced to enhance the performance of humidity sensors.Drawing on the noncontact perception capability,human/plant healthcare management,human-machine interactions as well as integrated humidity sensor-based feedback systems are presented.The burgeoning innovations in this research field will benefit human society,especially during the COVID-19 epidemic,where cross-infection should be averted and contactless sensation is highly desired.展开更多
Wall slip is a microscopic phenomenon of cemented paste backfill(CPB)slurry near the pipe wall,which has an important influence on the form of slurry pipe transport flow and velocity distribution.Directly probing the ...Wall slip is a microscopic phenomenon of cemented paste backfill(CPB)slurry near the pipe wall,which has an important influence on the form of slurry pipe transport flow and velocity distribution.Directly probing the wall slip characteristics using conventional experimental methods is difficult.Therefore,this paper established a noncontact experimental platform for monitoring the microscopic slip layer of CPB pipeline transport independently based on particle image velocimetry(PIV)and analyzed the effects of slurry temperature,pipe diameter,solid concentration,and slurry flow on the wall slip velocity of the CPB slurry,which refined the theory of the effect of wall slip characteristics on pipeline transport.The results showed that the CPB slurry had an extensive slip layer at the pipe wall with significant wall slip.High slurry temperature improved the degree of particle Brownian motion within the slurry and enhanced the wall slip effect.Increasing the pipe diameter was not conducive to the formation of the slurry slip layer and led to a transition in the CPB slurry flow pattern.The increase in the solid concentration raised the interlayer shear effect of CPB slurry flow and the slip velocity.The slip velocity value increased from 0.025 to 0.056 m·s^(-1)when the solid content improved from 55wt%to 65wt%.When slurry flow increased,the CPB slurry flocculation structure changed,which affected the slip velocity,and the best effect of slip layer resistance reduction was achieved when the transported flow rate was 1.01 m^(3)·h^(-1).The results had important theoretical significance for improving the stability and economy of the CPB slurry in the pipeline.展开更多
We have proposed a novel noncontact ultrasonic motor based on non-syinmetrical electrode driving. The configuration of this electrode and the fabrication process of rotors are presented. Its vibration characteristics ...We have proposed a novel noncontact ultrasonic motor based on non-syinmetrical electrode driving. The configuration of this electrode and the fabrication process of rotors are presented. Its vibration characteristics are computed and analysed by using the finite element method and studied experimentally. Good agreement between them is obtained. Moreover, it is also shown that this noncontact ultrasonic motor is operated in antisymmetric radial vibration mode of B21 mode. The maximum revolution speed for three-blade and six-blade rotors are 5100 and 3700r/min at an input voltage of 20V, respectively. Also, the noncontact high-speed revolution of the rotors can be realized by the parts of Ⅰ, Ⅲ of the electrode or Ⅱ, Ⅳ of the electrode. The levitation distance between the s tator and rotor is about 140μm according to the theoretical calculation and the experimental measurement.展开更多
AIM: To investigate the effects of baffle and intraocular pressure(IOP) on the aerosols generated in the noncontact tonometer(NCT) measurement and provide recommendations for the standardized use of the NCT during cor...AIM: To investigate the effects of baffle and intraocular pressure(IOP) on the aerosols generated in the noncontact tonometer(NCT) measurement and provide recommendations for the standardized use of the NCT during coronavirus disease 2019(COVID-19). METHODS: This clinical trial included 252 subjects(312 eyes) in The Eye Hospital, Wenzhou Medical University from March 7, 2020, to March 28, 2020. Sixty subjects(120 eyes) with normal IOP were divided into two groups. One group used an NCT without a baffle, another group used an NCT with a baffle. Another 192 subjects(192 eyes) were divided into four groups: Group A;(without a baffle+normal IOP), Group A;(without a baffle+high IOP), Group B;(with a baffle+normal IOP) and Group B;(with a baffle+high IOP). Particulate matter(PM) 2.5 and PM10 generated by all subjects were quantified during the NCT measurement. The IOP values were recorded simultaneously. Effects of baffle and IOP on aerosols generated during the NCT measurement were analyzed.RESULTS: In the normal eye group with a baffle, the aerosol density decreased in a wave-like shape near the NCT with the increase in the number of people measured for IOP, demonstrating no cumulative effect. However, in the normal eye group without a baffle, there was a cumulative effect. PM2.5 and PM10 in Group A;were higher than Group A;(both P<0.001). The PM2.5 and PM10 in Group B;were higher than Group B;(P<0.01, P<0.001 respectively). The PM10 of Group B;was lower than Group A;(P<0.01). PM2.5 in Group B;were lower than Group A;(P<0.01). The median of per capita PM2.5 and PM10 in the combined Group A;+A;were 0.80 and 1.10 μg/m;respectively, which were higher than 0.20 and 0.60 μg/m;in the combined Group B;+B;(both P<0.01). The median of per capita PM2.5 and PM10 in the combined Group A;+B;were 0.10 and 0.20 μg/m;respectively, which were lower than 1.30 and 1.70 μg/m;in the combined Group A;+B;(both P<0.001).CONCLUSION: More aerosols could be generated in patients with high IOP. After the NCT is equipped with a baffle, per capita aerosol density generated decreased significantly near the NCT;And with the increase in the number of people measured for IOP, the aerosols gradually dissipated near the NCT, demonstrating no cumulative effect. Therefore, it is suggested that the NCT should be equipped with a baffle, especially for patients with high IOP.展开更多
Integrated Ultrasonic Transducers (IUTs) have been developed for high-temperature nondestructive evaluation applications. In many field, it would be helpful if a pipe covered by a protective layer of about 10 cm thick...Integrated Ultrasonic Transducers (IUTs) have been developed for high-temperature nondestructive evaluation applications. In many field, it would be helpful if a pipe covered by a protective layer of about 10 cm thickness, which is under operation at several hundred Celsius, could be inspected from above the protective layer by an IUT. As a first step toward achieving the inspection of such a pipeline, an induction-based method using coils is presented together with IUTs. This study focuses on the effects of the separation distance (liftoff) between the coils on the ultrasonic signal strength and bandwidth of the IUTs. Ultrasonic signals were generated and received by the IUTs on a steel plate with a sufficient strength for thickness measurements when the liftoff was 20 cm. It was also shown that a ferrite disc together with the coils enhanced the received signal strength even when the liftoff was over 10 cm.展开更多
To increase the gripping area of noncontact end grippers(NCEGs), an array-type NCEG based on the Coanda mechanism is proposed, and its performance in gripping different garment fabrics(GFs) is studied. Firstly, the st...To increase the gripping area of noncontact end grippers(NCEGs), an array-type NCEG based on the Coanda mechanism is proposed, and its performance in gripping different garment fabrics(GFs) is studied. Firstly, the structure and the working mechanism of a single Coanda-based NCEG were analyzed. Secondly, four such grippers were arranged in array to form a minimum gripping unit. Then, the structure of the connecting plate(CP) to the gripper was optimized by simulation analysis to exclude airflow interference, and the adsorption performance of GFs with different fabric parameters was measured. Finally, the experimental results were analyzed to verify the scientific validity and the feasibility of the array-type arrangement. The results show that compared with other NCEGs, the array-type ones based on the Coanda mechanism are better at gripping various large-area GFs and offer better adsorption performance. This innovation provides a new solution to the problem of insufficient gripping area in GF gripping and is very important for improving the production efficiency of garment processing.展开更多
A noncontact user interface using image processing for people with neuromuscular diseases is presented in this paper. The user interface is composed of a Web camera and a PC, and allows users to manipulate the PC usin...A noncontact user interface using image processing for people with neuromuscular diseases is presented in this paper. The user interface is composed of a Web camera and a PC, and allows users to manipulate the PC using small movements of single finger. By using image processing techniques with the Web camera, the finger is appropriately detected from the images captured by it. Control boxes for pointing and text input functions are also made. To verify performances of the interface, some tasks are experimentally performed by three able-bodied subjects and a person suffering from spinal muscular atrophy. It was clear from the experimental results that all the subjects could smoothly nerforrn the t,~k~展开更多
This study aims to confirm whether noncontact monitoring of relative changes in blood pressure can be estimated using microwave radar sensors. First, an equation to estimate blood pressure was derived, after which, th...This study aims to confirm whether noncontact monitoring of relative changes in blood pressure can be estimated using microwave radar sensors. First, an equation to estimate blood pressure was derived, after which, the effectiveness of the estimation equation was confirmed using data obtained by a noncontact method while inducing variations in blood pressure. We considered that the Bramwell-Hill equation, which contains some parameters that directly indicate changes in blood pressure, would be an appropriate reference to construct an estimation equation for the noncontact method, because measurements using microwave radar sensors can measure minute scale motion on the skin surface induced by the pulsation of blood vessels. In order to estimate relative changes in blood pressure, we considered a simple equation including the pulse transit time (PTT), amplitude of signals and body dimensions as parameters. To verify the effectiveness of the equation for estimating changes in blood pressure, two experiments were conducted: a cycling task using an ergometer, which induces blood pressure fluctuations because of changes in cardiac output, and a task using the Valsalva maneuver, which induces blood pressure fluctuations because of changes in vascular resistance. The results obtained from the two experiments suggested that the proposed equation using microwave radar sensors can accurately estimate relative changes of blood pressure. In particular, relatively favorable results were obtained for the changes in blood pressure induced by the changes in cardiac volume. Although many issues remain, this method could be expected to contribute to the continuous evaluation of cardiac function while reducing the burden on patients.展开更多
Lipid imaging by conventional photoacoustic microscopy subjects to direct contact sensing with relatively low detection bandwidth and sensitivity,which induces superficial imaging depth and low signalto-noise ratio(SN...Lipid imaging by conventional photoacoustic microscopy subjects to direct contact sensing with relatively low detection bandwidth and sensitivity,which induces superficial imaging depth and low signalto-noise ratio(SNR)in practical imaging scenarios.Herein,we present a photoacoustic remote sensing microscopy for lipid distribution mapping in bio-tissue,featuring noncontact implementation,broad detection bandwidth,deep penetration depth,and high SNR.A tailored high-energy pulsed laser source with a spectrum centered at 1750 nm is used as the excitation beam,while a cofocused 1550 nm continuous-wave beam is used as the probe signal.The pump wavelength is selected to overlap the first overtone of the C-H bond in response to the intensive absorption of lipid molecules,which introduces a much-enhanced SNR(55 dB)onto photoacoustic remote sensing(PARS)signals.Meanwhile,the optical sensing scheme of the photoacoustic signals provides broadband detection compared to the acoustic transducer and refrains the bio-samples from direct contact operations by eliminating the ultrasonic coupling medium.Taking merits of the high detection sensitivity,deep penetration depth,broadband detection,and high resolution of the PARS system,high-quality tissue scale lipid imaging is demonstrated in a model organism and brain slice.展开更多
Virtual reality(VR)is an emerging communication means and creates extensive opportunities in interacting scenarios such as remote collaboration and metaverse.Human-machine interfaces(HMIs)play important roles in VR as...Virtual reality(VR)is an emerging communication means and creates extensive opportunities in interacting scenarios such as remote collaboration and metaverse.Human-machine interfaces(HMIs)play important roles in VR as they provide interaction platforms between users and virtual environments.However,traditional VR HMIs based on handheld devices or keyboards cannot recognize diverse three-dimensional(3D)gestures,which results in limited freedom of VR interactions.Here,we report a noncontact VR HMI enabled by an electret-nanofiber-based triboelectric sensor(ETS),which is fabricated by the electrospun polylactic acid/thermoplastic polyurethane(PLA/TPU)electret nanofiber film.The nanofiber structure of PLA/TPU electret enhanced the charge retention ability of triboelectric sensor and thus significantly improved its signal strength and stability.Integrated with a deep learning-based multilayer perceptron neural network,the ETS realizes the recognition of 18 different types of 3D gestures with a high average accuracy of 97.3%.An intelligent noncontact VR interactive system based on the ETS is further developed,which is used to manipulate game characters for performing different actions by 3D gestures.Compared with traditional VR HMIs,the proposed VR HMI based on PLA/TPU electret nanofiber film can detect various 3D gestures and offers a superior interaction freedom.This work for the first time introduces the triboelectric 3D gesture recognition method to the VR HMIs,and could make the interaction between human and virtual environments become more efficient and fascinating.展开更多
Mechanical signal capture without physical contact has emerged as a highly promising research field and attracted tremendous attention due to its prosperous applications in household medical care,lifestyle monitoring ...Mechanical signal capture without physical contact has emerged as a highly promising research field and attracted tremendous attention due to its prosperous applications in household medical care,lifestyle monitoring and remote operation,offering users high level of safety,convenience and comfort.Moreover,noncontact sensing is ideal to maximize the immersive user experience in the human–machine interaction(HMI),eliminating interference to human activities and mechanical fatigue to the sensor,simultaneously.Herein,we report a self-powered flexible sensor integrated with irradiation cross-linked polypropylene(IXPP)piezoelectret film for noncontact sensing,featuring multi-functions to detect mechanical signals transmitted through solid,liquid and gaseous media and would facilitate their versatile practical applications.The folded-structure configuration of the sensor facilitates the improvement of the noncontact sensing sensitivity.For solid media,such as the rectangular wooden stick used in this study,the sensor can detect mechanical stimulus exerted at a distance of 100 cm.A system detection sensitivity up to 57 pC/kPa with a low detection limit of 0.6 kPa is achieved at a noncontact distance of 10 cm.Even when partly or completely immersed in water,the sensor effectively traces movement signals of human bodies underwater,demonstrating great advantages for non-inductive aquatic fitness training monitoring.Furthermore,due to the low acoustic impedance of piezoelectret film,speech recognition through gaseous medium is also achieved.We further introduce application demonstrations of the developed film sensors to monitor exercise postures and physiological signals without direct contact between human body and the sensor,displaying great potential to be incorporated into future smart electronics.This study commendably expands the application scope of piezoelectret materials,which will have profound implications for exploring novel intelligent human–machine interactions.展开更多
We present a novel noncontact ultrasound(US)and photoacoustic imaging(PAI)system,overcoming the limitations of traditional coupling media.Using a long coherent length laser,we employ a homodyne free-space Mach-Zehnder...We present a novel noncontact ultrasound(US)and photoacoustic imaging(PAI)system,overcoming the limitations of traditional coupling media.Using a long coherent length laser,we employ a homodyne free-space Mach-Zehnder setup with zero-crossing triggering,achieving a noise equivalent pressure of 703 Pa at 5 MHz and a-6 dB bandwidth of 1 to8.54 MHz.We address the phase uncertainty inherent in the homodyne method.Scanning the noncontact US probe enables photoacoustic computed tomography(PACT).Phantom studies demonstrate imaging performance and system stability,underscoring the potential of our system for noncontact US sensing and PAI.展开更多
A highly distorted chiral nanographene structure composed of triple corannulene-fused[5]helicenes is prepared with the help of the Heck reaction and oxidative photocyclization with an overall isolated yield of 28%.The...A highly distorted chiral nanographene structure composed of triple corannulene-fused[5]helicenes is prepared with the help of the Heck reaction and oxidative photocyclization with an overall isolated yield of 28%.The complex three-dimensional(3D)structure of the bowl-helix hybrid nanostructure is studied by a combination of noncontact atomic force microscopy(AFM)and scanning tunneling microscopy(STM)on the Cu(111)surface,density functional theory calculations,AFM/STM simulations,and high-performance liquid chromatography-electronic circular dichroism analysis.This examination reveals a molecular structure in which the three bowl-shaped corannulene bladesd position themselves in a C3-symmetric fashion around a highly twisted triphenylene core.The molecule appears to be shaped like a propeller in which the concave side of the bowls face away from the connected[5]helicene motif.The chirality of the nanostructure is confirmed by the direct visualization of both MMM and PPP enantiomers at the single-molecule level by scanning probe microscopies.These results underline that submolecular resolution imaging by AFM/STM is a powerful real-space tool for the stereochemical characterization of 3D curved chiral nanographene structures.展开更多
As crucial parts of an aeroengine,blades are vulnerable to damage from long-term operation in harsh environments.The ultrasonic surface rolling process(USRP)is a novel surface treatment technique that can highly impro...As crucial parts of an aeroengine,blades are vulnerable to damage from long-term operation in harsh environments.The ultrasonic surface rolling process(USRP)is a novel surface treatment technique that can highly improve the mechanical behavior of blades.During secondary machining,the nominal blade model cannot be used for secondary machining path generation due to the deviation between the actual and nominal blades.The clamping error of the blade also affects the precision of secondary machining.This study presents a two-sided USRP(TS-USRP)machining for aeroengine blades on the basis of on-machine noncontact measurement.First,a TS-USRP machining system for blade is developed.Second,a 3D scanning system is used to obtain the point cloud of the blade,and a series of point cloud processing steps is performed.A local point cloud automatic extraction algorithm is introduced to extract the point cloud of the strengthened region of the blade.Then,the tool path is designed on the basis of the extracted point cloud.Finally,an experiment is conducted on an actual blade,with results showing that the proposed method is effective and efficient.展开更多
Noncontact interaction systems have attracted considerable research attention in recent years because of convenient operation,sterility,and injury prevention.However,the insufficient sensing distance and weak robustne...Noncontact interaction systems have attracted considerable research attention in recent years because of convenient operation,sterility,and injury prevention.However,the insufficient sensing distance and weak robustness of noncontact interaction systems for complex environments limit their practical applications.Here,we designed an integrated optical noncontact controlling system(ONCS)based on PtTe_(x)/Si optoelectronic heterojunction array.Broadband sensitive photoresponse is realized at zero bias voltage,with excellent detectivity and responsivity,boosting the noncontact sensing distance to at least 150 mm.Consequently,the system can perform noncontact detection,encoding,and control by recognizing shadow-induced spatiotemporal sequence changes in heterojunction array photocurrents.As a proof of concept,different interactive functions have been demonstrated with good accuracy and robustness by encoding finger movement above the ONCS.This study provides a new perspective for constructing high-performance noncontact interaction systems.展开更多
基金financially supported by the National Natural Science Foundation of China(No.22305033 received by Z.Y.L.,No.52161135102 received by P.Y.W.)the Fundamental Research Funds for the Central Universities(No.2232024A-05 received by Z.Y.L.)。
文摘Smart actuators and wearable and implantable devices have attracted much attention in healthcare and environmental sensing.Flexible electronic and ionic materials are the two main approaches used to construct these devices.Among them,hydrogel-based ionic materials offer unique advantages,such as biocompatibility and adaptable mechanical properties.However,ionic hydrogels encounter challenges in achieving wirelessly powered and noncontact sensing.To address this,we introduce MXene nanosheets to construct ionotronic hydrogels.Leveraging the rich surface charges and electronic conductivity of MXene nanosheets,ionotronic hydrogels can harvest vibrational and electromagnetic waves as electrical energy and enable noncontact sensing.Under ultrasound,it can continuously generate voltages up to 85 V and light up lightemitting diodes,promising wireless charging of implanted devices.In addition,it achieves an absorption coefficient of 0.2 for 915 MHz electromagnetic waves,enabling noncontact sensing through radio frequency identification.Notably,the physically crosslinked network of the MXenebased hydrogels maintained structural and performance stability under ultrasonic stimulation and exhibited self-healing properties.Even when cut into two halves,the self-healing hydrogel fully regenerates its original performance.This study provides insight into the development of ionotronic hydrogels for wirelessly powered and noncontact sensing in smart actuators and wearable and implantable applications.
基金supported by the National Science and Technology Innovation 2030 Major Project(Grant No.2022ZD0208601)the National Natural Science Foundation of China(Grant No.52105593 and 51975513)the Natural Science Foundation of Zhejiang Province,China(No.LR20E050003)。
文摘In the past decade,the global industry and research attentions on intelligent skin-like electronics have boosted their applications in diverse fields including human healthcare,Internet of Things,human–machine interfaces,artificial intelligence and soft robotics.Among them,flexible humidity sensors play a vital role in noncontact measurements relying on the unique property of rapid response to humidity change.This work presents an overview of recent advances in flexible humidity sensors using various active functional materials for contactless monitoring.Four categories of humidity sensors are highlighted based on resistive,capacitive,impedance-type and voltage-type working mechanisms.Furthermore,typical strategies including chemical doping,structural design and Joule heating are introduced to enhance the performance of humidity sensors.Drawing on the noncontact perception capability,human/plant healthcare management,human-machine interactions as well as integrated humidity sensor-based feedback systems are presented.The burgeoning innovations in this research field will benefit human society,especially during the COVID-19 epidemic,where cross-infection should be averted and contactless sensation is highly desired.
基金financially supported by the National Natural Science Foundation of China (Nos.51774137 and 51804121)。
文摘Wall slip is a microscopic phenomenon of cemented paste backfill(CPB)slurry near the pipe wall,which has an important influence on the form of slurry pipe transport flow and velocity distribution.Directly probing the wall slip characteristics using conventional experimental methods is difficult.Therefore,this paper established a noncontact experimental platform for monitoring the microscopic slip layer of CPB pipeline transport independently based on particle image velocimetry(PIV)and analyzed the effects of slurry temperature,pipe diameter,solid concentration,and slurry flow on the wall slip velocity of the CPB slurry,which refined the theory of the effect of wall slip characteristics on pipeline transport.The results showed that the CPB slurry had an extensive slip layer at the pipe wall with significant wall slip.High slurry temperature improved the degree of particle Brownian motion within the slurry and enhanced the wall slip effect.Increasing the pipe diameter was not conducive to the formation of the slurry slip layer and led to a transition in the CPB slurry flow pattern.The increase in the solid concentration raised the interlayer shear effect of CPB slurry flow and the slip velocity.The slip velocity value increased from 0.025 to 0.056 m·s^(-1)when the solid content improved from 55wt%to 65wt%.When slurry flow increased,the CPB slurry flocculation structure changed,which affected the slip velocity,and the best effect of slip layer resistance reduction was achieved when the transported flow rate was 1.01 m^(3)·h^(-1).The results had important theoretical significance for improving the stability and economy of the CPB slurry in the pipeline.
基金Project supported by the National Natural Science Foundation of China （Grant No 50205017）.
文摘We have proposed a novel noncontact ultrasonic motor based on non-syinmetrical electrode driving. The configuration of this electrode and the fabrication process of rotors are presented. Its vibration characteristics are computed and analysed by using the finite element method and studied experimentally. Good agreement between them is obtained. Moreover, it is also shown that this noncontact ultrasonic motor is operated in antisymmetric radial vibration mode of B21 mode. The maximum revolution speed for three-blade and six-blade rotors are 5100 and 3700r/min at an input voltage of 20V, respectively. Also, the noncontact high-speed revolution of the rotors can be realized by the parts of Ⅰ, Ⅲ of the electrode or Ⅱ, Ⅳ of the electrode. The levitation distance between the s tator and rotor is about 140μm according to the theoretical calculation and the experimental measurement.
文摘AIM: To investigate the effects of baffle and intraocular pressure(IOP) on the aerosols generated in the noncontact tonometer(NCT) measurement and provide recommendations for the standardized use of the NCT during coronavirus disease 2019(COVID-19). METHODS: This clinical trial included 252 subjects(312 eyes) in The Eye Hospital, Wenzhou Medical University from March 7, 2020, to March 28, 2020. Sixty subjects(120 eyes) with normal IOP were divided into two groups. One group used an NCT without a baffle, another group used an NCT with a baffle. Another 192 subjects(192 eyes) were divided into four groups: Group A;(without a baffle+normal IOP), Group A;(without a baffle+high IOP), Group B;(with a baffle+normal IOP) and Group B;(with a baffle+high IOP). Particulate matter(PM) 2.5 and PM10 generated by all subjects were quantified during the NCT measurement. The IOP values were recorded simultaneously. Effects of baffle and IOP on aerosols generated during the NCT measurement were analyzed.RESULTS: In the normal eye group with a baffle, the aerosol density decreased in a wave-like shape near the NCT with the increase in the number of people measured for IOP, demonstrating no cumulative effect. However, in the normal eye group without a baffle, there was a cumulative effect. PM2.5 and PM10 in Group A;were higher than Group A;(both P<0.001). The PM2.5 and PM10 in Group B;were higher than Group B;(P<0.01, P<0.001 respectively). The PM10 of Group B;was lower than Group A;(P<0.01). PM2.5 in Group B;were lower than Group A;(P<0.01). The median of per capita PM2.5 and PM10 in the combined Group A;+A;were 0.80 and 1.10 μg/m;respectively, which were higher than 0.20 and 0.60 μg/m;in the combined Group B;+B;(both P<0.01). The median of per capita PM2.5 and PM10 in the combined Group A;+B;were 0.10 and 0.20 μg/m;respectively, which were lower than 1.30 and 1.70 μg/m;in the combined Group A;+B;(both P<0.001).CONCLUSION: More aerosols could be generated in patients with high IOP. After the NCT is equipped with a baffle, per capita aerosol density generated decreased significantly near the NCT;And with the increase in the number of people measured for IOP, the aerosols gradually dissipated near the NCT, demonstrating no cumulative effect. Therefore, it is suggested that the NCT should be equipped with a baffle, especially for patients with high IOP.
文摘Integrated Ultrasonic Transducers (IUTs) have been developed for high-temperature nondestructive evaluation applications. In many field, it would be helpful if a pipe covered by a protective layer of about 10 cm thickness, which is under operation at several hundred Celsius, could be inspected from above the protective layer by an IUT. As a first step toward achieving the inspection of such a pipeline, an induction-based method using coils is presented together with IUTs. This study focuses on the effects of the separation distance (liftoff) between the coils on the ultrasonic signal strength and bandwidth of the IUTs. Ultrasonic signals were generated and received by the IUTs on a steel plate with a sufficient strength for thickness measurements when the liftoff was 20 cm. It was also shown that a ferrite disc together with the coils enhanced the received signal strength even when the liftoff was over 10 cm.
基金National Key Research and Development Program of China (No.2018YFB1308801)。
文摘To increase the gripping area of noncontact end grippers(NCEGs), an array-type NCEG based on the Coanda mechanism is proposed, and its performance in gripping different garment fabrics(GFs) is studied. Firstly, the structure and the working mechanism of a single Coanda-based NCEG were analyzed. Secondly, four such grippers were arranged in array to form a minimum gripping unit. Then, the structure of the connecting plate(CP) to the gripper was optimized by simulation analysis to exclude airflow interference, and the adsorption performance of GFs with different fabric parameters was measured. Finally, the experimental results were analyzed to verify the scientific validity and the feasibility of the array-type arrangement. The results show that compared with other NCEGs, the array-type ones based on the Coanda mechanism are better at gripping various large-area GFs and offer better adsorption performance. This innovation provides a new solution to the problem of insufficient gripping area in GF gripping and is very important for improving the production efficiency of garment processing.
文摘A noncontact user interface using image processing for people with neuromuscular diseases is presented in this paper. The user interface is composed of a Web camera and a PC, and allows users to manipulate the PC using small movements of single finger. By using image processing techniques with the Web camera, the finger is appropriately detected from the images captured by it. Control boxes for pointing and text input functions are also made. To verify performances of the interface, some tasks are experimentally performed by three able-bodied subjects and a person suffering from spinal muscular atrophy. It was clear from the experimental results that all the subjects could smoothly nerforrn the t,~k~
文摘This study aims to confirm whether noncontact monitoring of relative changes in blood pressure can be estimated using microwave radar sensors. First, an equation to estimate blood pressure was derived, after which, the effectiveness of the estimation equation was confirmed using data obtained by a noncontact method while inducing variations in blood pressure. We considered that the Bramwell-Hill equation, which contains some parameters that directly indicate changes in blood pressure, would be an appropriate reference to construct an estimation equation for the noncontact method, because measurements using microwave radar sensors can measure minute scale motion on the skin surface induced by the pulsation of blood vessels. In order to estimate relative changes in blood pressure, we considered a simple equation including the pulse transit time (PTT), amplitude of signals and body dimensions as parameters. To verify the effectiveness of the equation for estimating changes in blood pressure, two experiments were conducted: a cycling task using an ergometer, which induces blood pressure fluctuations because of changes in cardiac output, and a task using the Valsalva maneuver, which induces blood pressure fluctuations because of changes in vascular resistance. The results obtained from the two experiments suggested that the proposed equation using microwave radar sensors can accurately estimate relative changes of blood pressure. In particular, relatively favorable results were obtained for the changes in blood pressure induced by the changes in cardiac volume. Although many issues remain, this method could be expected to contribute to the continuous evaluation of cardiac function while reducing the burden on patients.
基金supported by the Research Grants Council of the Hong Kong Special Administrative Region of China(Grant Nos.HKU 17210522,HKU C7074-21G,HKU 17205321,HKU 17200219,HKU 17209018,and CityU T42-103/16-N)the Health@InnoHK Program of the Innovation and Technology Commission of the Hong Kong SAR Government.
文摘Lipid imaging by conventional photoacoustic microscopy subjects to direct contact sensing with relatively low detection bandwidth and sensitivity,which induces superficial imaging depth and low signalto-noise ratio(SNR)in practical imaging scenarios.Herein,we present a photoacoustic remote sensing microscopy for lipid distribution mapping in bio-tissue,featuring noncontact implementation,broad detection bandwidth,deep penetration depth,and high SNR.A tailored high-energy pulsed laser source with a spectrum centered at 1750 nm is used as the excitation beam,while a cofocused 1550 nm continuous-wave beam is used as the probe signal.The pump wavelength is selected to overlap the first overtone of the C-H bond in response to the intensive absorption of lipid molecules,which introduces a much-enhanced SNR(55 dB)onto photoacoustic remote sensing(PARS)signals.Meanwhile,the optical sensing scheme of the photoacoustic signals provides broadband detection compared to the acoustic transducer and refrains the bio-samples from direct contact operations by eliminating the ultrasonic coupling medium.Taking merits of the high detection sensitivity,deep penetration depth,broadband detection,and high resolution of the PARS system,high-quality tissue scale lipid imaging is demonstrated in a model organism and brain slice.
基金supported by the National Natural Science Foundation of China(No.52303112)the Henan Province Science and Technology Research and Development Program Joint Fund Advantageous Discipline Cultivation Project(No.232301420033)+1 种基金the China Postdoctoral Science Foundation(Nos.2022TQ0281 and 2023M733213)the Key R&D and Promotion Special(Scientific Problem Tackling)Project of Henan Province(No.242102231014).
文摘Virtual reality(VR)is an emerging communication means and creates extensive opportunities in interacting scenarios such as remote collaboration and metaverse.Human-machine interfaces(HMIs)play important roles in VR as they provide interaction platforms between users and virtual environments.However,traditional VR HMIs based on handheld devices or keyboards cannot recognize diverse three-dimensional(3D)gestures,which results in limited freedom of VR interactions.Here,we report a noncontact VR HMI enabled by an electret-nanofiber-based triboelectric sensor(ETS),which is fabricated by the electrospun polylactic acid/thermoplastic polyurethane(PLA/TPU)electret nanofiber film.The nanofiber structure of PLA/TPU electret enhanced the charge retention ability of triboelectric sensor and thus significantly improved its signal strength and stability.Integrated with a deep learning-based multilayer perceptron neural network,the ETS realizes the recognition of 18 different types of 3D gestures with a high average accuracy of 97.3%.An intelligent noncontact VR interactive system based on the ETS is further developed,which is used to manipulate game characters for performing different actions by 3D gestures.Compared with traditional VR HMIs,the proposed VR HMI based on PLA/TPU electret nanofiber film can detect various 3D gestures and offers a superior interaction freedom.This work for the first time introduces the triboelectric 3D gesture recognition method to the VR HMIs,and could make the interaction between human and virtual environments become more efficient and fascinating.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.62201392,12174061 and 12374451).
文摘Mechanical signal capture without physical contact has emerged as a highly promising research field and attracted tremendous attention due to its prosperous applications in household medical care,lifestyle monitoring and remote operation,offering users high level of safety,convenience and comfort.Moreover,noncontact sensing is ideal to maximize the immersive user experience in the human–machine interaction(HMI),eliminating interference to human activities and mechanical fatigue to the sensor,simultaneously.Herein,we report a self-powered flexible sensor integrated with irradiation cross-linked polypropylene(IXPP)piezoelectret film for noncontact sensing,featuring multi-functions to detect mechanical signals transmitted through solid,liquid and gaseous media and would facilitate their versatile practical applications.The folded-structure configuration of the sensor facilitates the improvement of the noncontact sensing sensitivity.For solid media,such as the rectangular wooden stick used in this study,the sensor can detect mechanical stimulus exerted at a distance of 100 cm.A system detection sensitivity up to 57 pC/kPa with a low detection limit of 0.6 kPa is achieved at a noncontact distance of 10 cm.Even when partly or completely immersed in water,the sensor effectively traces movement signals of human bodies underwater,demonstrating great advantages for non-inductive aquatic fitness training monitoring.Furthermore,due to the low acoustic impedance of piezoelectret film,speech recognition through gaseous medium is also achieved.We further introduce application demonstrations of the developed film sensors to monitor exercise postures and physiological signals without direct contact between human body and the sensor,displaying great potential to be incorporated into future smart electronics.This study commendably expands the application scope of piezoelectret materials,which will have profound implications for exploring novel intelligent human–machine interactions.
基金supported by the National Key Research and Development Program of China(No.2017YFE0104200)the Beijing Natural Science Foundation(No.JQ18023)+1 种基金the National Natural Science Foundation of China(Nos.81421004 and 61971447)the National Key Instrumentation Development Project of China(No.2013YQ030651)。
文摘We present a novel noncontact ultrasound(US)and photoacoustic imaging(PAI)system,overcoming the limitations of traditional coupling media.Using a long coherent length laser,we employ a homodyne free-space Mach-Zehnder setup with zero-crossing triggering,achieving a noise equivalent pressure of 703 Pa at 5 MHz and a-6 dB bandwidth of 1 to8.54 MHz.We address the phase uncertainty inherent in the homodyne method.Scanning the noncontact US probe enables photoacoustic computed tomography(PACT).Phantom studies demonstrate imaging performance and system stability,underscoring the potential of our system for noncontact US sensing and PAI.
基金Financial support from the Ministry of Education Singapore under the AcRF Tier 1(MOE T1 RG11/21)and AcRF Tier 2(MOE-T2EP10221-0002)The Deutsche Forschungsgemeinschaft via grants(nos.SCHI 619/13 and EB535/1-1)+5 种基金the GRK(Research Training Group)2204“Substitute Materials for Sustainable Energy Technologies”the LOEWE Program of Excellence of the Federal State of Hesse(LOEWE Focus Group PriOSS“Principles of On-Surface Synthesis”)the National Natural Science Foundation of China(grant nos.21790053,51821002,and 22072103)the National Major State Basic Research Development Program of China(grant nos.2017YFA0205000 and 2017YFA0205002)the Collaborative Innovation Center of Suzhou Nano Science&Technologythe 111 Project are also acknowledged for their financial support.
文摘A highly distorted chiral nanographene structure composed of triple corannulene-fused[5]helicenes is prepared with the help of the Heck reaction and oxidative photocyclization with an overall isolated yield of 28%.The complex three-dimensional(3D)structure of the bowl-helix hybrid nanostructure is studied by a combination of noncontact atomic force microscopy(AFM)and scanning tunneling microscopy(STM)on the Cu(111)surface,density functional theory calculations,AFM/STM simulations,and high-performance liquid chromatography-electronic circular dichroism analysis.This examination reveals a molecular structure in which the three bowl-shaped corannulene bladesd position themselves in a C3-symmetric fashion around a highly twisted triphenylene core.The molecule appears to be shaped like a propeller in which the concave side of the bowls face away from the connected[5]helicene motif.The chirality of the nanostructure is confirmed by the direct visualization of both MMM and PPP enantiomers at the single-molecule level by scanning probe microscopies.These results underline that submolecular resolution imaging by AFM/STM is a powerful real-space tool for the stereochemical characterization of 3D curved chiral nanographene structures.
基金The authors gratefully acknowledge the financial support extended by the National Natural Science Foundation of China(Grant Nos.51975214,51725503,and 51575183)the 111 Project.Zhang X C is also grateful for the support by the Major Program of the National Natural Science Foundation of Shanghai(Grant No.2019-01-07-00-02-E00068).
文摘As crucial parts of an aeroengine,blades are vulnerable to damage from long-term operation in harsh environments.The ultrasonic surface rolling process(USRP)is a novel surface treatment technique that can highly improve the mechanical behavior of blades.During secondary machining,the nominal blade model cannot be used for secondary machining path generation due to the deviation between the actual and nominal blades.The clamping error of the blade also affects the precision of secondary machining.This study presents a two-sided USRP(TS-USRP)machining for aeroengine blades on the basis of on-machine noncontact measurement.First,a TS-USRP machining system for blade is developed.Second,a 3D scanning system is used to obtain the point cloud of the blade,and a series of point cloud processing steps is performed.A local point cloud automatic extraction algorithm is introduced to extract the point cloud of the strengthened region of the blade.Then,the tool path is designed on the basis of the extracted point cloud.Finally,an experiment is conducted on an actual blade,with results showing that the proposed method is effective and efficient.
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.61625404,61874111,61888102 and 62022079)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2020115).
文摘Noncontact interaction systems have attracted considerable research attention in recent years because of convenient operation,sterility,and injury prevention.However,the insufficient sensing distance and weak robustness of noncontact interaction systems for complex environments limit their practical applications.Here,we designed an integrated optical noncontact controlling system(ONCS)based on PtTe_(x)/Si optoelectronic heterojunction array.Broadband sensitive photoresponse is realized at zero bias voltage,with excellent detectivity and responsivity,boosting the noncontact sensing distance to at least 150 mm.Consequently,the system can perform noncontact detection,encoding,and control by recognizing shadow-induced spatiotemporal sequence changes in heterojunction array photocurrents.As a proof of concept,different interactive functions have been demonstrated with good accuracy and robustness by encoding finger movement above the ONCS.This study provides a new perspective for constructing high-performance noncontact interaction systems.
