With the intelligent upgrading of manufacturing equipment,achieving high-precision and efficient fault diagnosis is essential to enhance equipment stability and increase productivity.Online monitoring and fault diagno...With the intelligent upgrading of manufacturing equipment,achieving high-precision and efficient fault diagnosis is essential to enhance equipment stability and increase productivity.Online monitoring and fault diagnosis technology play a critical role in improving the stability of metal additive manufacturing equipment.However,the limited proportion of fault data during operation challenges the accuracy and efficiency of multi-classification models due to excessive redundant data.A multi-sensor and principal component analysis(PCA)and support vector machine(SVM)asymptotic classification(PCSV)for additive manufacturing fault diagnosis method is proposed,and it divides the fault diagnosis into two steps.In the first step,real-time data are evaluated using the T2 and Q statistical parameters of the PCAmodel to identify potential faults while filtering non-fault data,thereby reducing redundancy and enhancing real-time efficiency.In the second step,the identified fault data are input into the SVM model for precise multi-class classification of fault categories.The PCSV method advances the field by significantly improving diagnostic accuracy and efficiency,achieving an accuracy of 99%,a diagnosis time of 0.65 s,and a training time of 503 s.The experimental results demonstrate the sophistication of the PCSV method for high-precision and high-efficiency fault diagnosis of small fault samples.展开更多
Voxel-based morphometry has been used in the study of alterations in brain structure in type 1 diabetes mellitus patients. These changes are associated with clinical indices. The age at onset, pathogenesis, and treatm...Voxel-based morphometry has been used in the study of alterations in brain structure in type 1 diabetes mellitus patients. These changes are associated with clinical indices. The age at onset, pathogenesis, and treatment of type 1 diabetes mellitus are different from those for type 2 diabetes mellitus. Thus, type 1 and type 2 diabetes mellitus may have different impacts on brain structure. Only a few studies of the alterations in brain structure in type 2 diabetes mellitus patients using voxel-based morphometry have been conducted, with inconsistent results. We detected subtle changes in the brain structure of 23 cases of type 2 diabetes mellitus, and demonstrated that there was no significant difference between the total volume of gray and white matter of the brain of type 2 diabetes mellitus patients and that in controls. Regional atrophy of gray matter mainly occurred in the right temporal and left occipital cortex, while regional atrophy of white matter involved the right temporal lobe and the right cerebellar hemisphere. The ankle-brachial index in patients with type 2 diabetes mellitus strongly correlated with the volume of brain regions in the default mode network. The ankle-brachial index, followed by the level of glycosylated hemoglobin, most strongly correlated with the volume of gray matter in the right temporal lobe. These data suggest that voxel-based morphometry could detect small structural changes in patients with type 2 diabetes mellitus. Early macrovascular atherosclerosis may play a crucial role in subtle brain atro- phy in type 2 diabetes mellitus patients, with chronic hyperglycemia playing a lesser role.展开更多
Traditional orthopedic metal implants,such as titanium(Ti),Ti alloys,and cobalt-chromium(Co-Cr)alloys,cannot be degraded in vivo.Fracture patients is must always suffer a second operation to remove the implants.Moreov...Traditional orthopedic metal implants,such as titanium(Ti),Ti alloys,and cobalt-chromium(Co-Cr)alloys,cannot be degraded in vivo.Fracture patients is must always suffer a second operation to remove the implants.Moreover,stress shielding,or stress protection occurs when traditional orthopedic metal implants are applied in fractures surgery.The mechanical shunt produced by traditional orthopedic metal implants can cause bone loss over time,resulting in decreased bone strength and delayed fracture healing.Biodegradable metals that‘biocorrode’are currently attracting significant interest in the orthopedics field due to their suitability as temporary implants.As one of the biodegradable metals,magnesium(Mg)and Mg alloys have gained interest in the field of medicine due to their low density,excellent biocompatibility,high bioresorbability,and proper mechanical properties.Additionally,Mg ions released from the metal implants can promote osteogenesis and angiogenesis during the degradation process in vivo,which is substantially better for orthopedic fixation than other bioinert metal materials.Therefore,this review focuses on the properties,fabrication,biological functions,and surface modification of Mg-based alloys as novel bioabsorbable biomaterials for orthopedic applications.展开更多
The bone regenerative scaffold with the tailored degradation rate matching with the growth rate of the new bone is essential for adolescent bone repair.To satisfy these requirement,we proposed bone tissue scaffolds wi...The bone regenerative scaffold with the tailored degradation rate matching with the growth rate of the new bone is essential for adolescent bone repair.To satisfy these requirement,we proposed bone tissue scaffolds with controlled degradation rate using osteoinductive materials(Ca-P bioceramics),which is expected to present a controllable biodegradation rate for patients who need bone regeneration.Physicochemical properties,porosity,compressive strength and degradation properties of the scaffolds were studied.3D printed Ca-P scaffold(3DS),gas foaming Ca-P scaffold(FS)and autogenous bone(AB)were used in vivo for personalized beagle skull defect repair.Histological results indicated that the 3DS was highly vascularized and well combined with surrounding tissues.FS showed obvious newly formed bone tissues.AB showed the best repair effect,but it was found that AB scaffolds were partially absorbed and degraded.This study indicated that the 3D printed Ca-P bioceramics with tailored biodegradation rate is a promising candidate for personalized skull bone tissue reconstruction.展开更多
The multilayered structure thin films(Gd_(2)(MoO_(4))_(3):Ho(Tm)/Yb@Gd_(2)(MoO_(4))_(3):Yb) were prepared through sol-gel and spin-coating method,while the average thinness was nearly 140 nm.We investigated the up-con...The multilayered structure thin films(Gd_(2)(MoO_(4))_(3):Ho(Tm)/Yb@Gd_(2)(MoO_(4))_(3):Yb) were prepared through sol-gel and spin-coating method,while the average thinness was nearly 140 nm.We investigated the up-conversion luminescence of Gd_(2)(MoO_(4))_(3):Ho(Tm)/Yb@Gd_(2)(MoO_(4))_(3):Yb thin films,The results show that the double-layer structured thin films are able to increase the emission intensity.The fluorescence enhancement factors of the luminescence from Gd_(2)(MoO_(4))_(3):Ho/Yb@Gd_(2)(MoO_(4))_(3):Yb thin films,located at540 and 662 nm,reach 7.5 and 4.3,respectively.And the enhancement factors of emissions located at450,475 and 650 nm(Gd_(2)(MoO_(4))_(3):Tm/Yb@Gd_(2)(MoO_(4))_(3):Yb) reach 9,2 and 2,respectively.The considerable enhancement is due to the suppression of surface quenching and energy harvesting via the Yb ions in the outer shell.In addition,the emission color of thin films can be modulated from yellow to blue via tuning the number of Gd_(2)(MoO_(4))_(3):Ho/Yb and Gd_(2)(MoO_(4))_(3):Tm/Yb layers,which provides a feasible strategy to tune the up-conversion emission color.展开更多
The anisotropic properties and applications ofβ-gallium oxide(β-Ga_(2)O_(3))are comprehensively reviewed.All the anisotropic properties are essentially resulted from the anisotropic crystal structure.The process flo...The anisotropic properties and applications ofβ-gallium oxide(β-Ga_(2)O_(3))are comprehensively reviewed.All the anisotropic properties are essentially resulted from the anisotropic crystal structure.The process flow of how to exfoliate nanoflakes from bulk material is introduced.Anisotropic optical properties,including optical bandgap,Raman and photolumines-cence characters are comprehensively reviewed.Three measurement configurations of angle-resolved polarized Raman spec-tra(ARPRS)are reviewed,with Raman intensity formulas calculated with Raman tensor elements.The method to obtain the Raman tensor elements of phonon modes through experimental fitting is also introduced.In addition,the anisotropy in elec-tron mobility and affinity are discussed.The applications,especially polarization photodetectors,based onβ-Ga_(2)O_(3)were summa-rized comprehensively.Three kinds of polarization detection mechanisms based on material dichroism,1D morphology and metal-grids are discussed in-depth.This review paper provides a framework for anisotropic optical and electric properties ofβ-Ga_(2)O_(3),as well as the applications based on these characters,and is expected to lead to a wider discussion on this topic.展开更多
Subpixel localization techniques for estimating the positions of point-like images captured by pixelated image sensors have been widely used in diverse optical measurement fields.With unavoidable imaging noise,there i...Subpixel localization techniques for estimating the positions of point-like images captured by pixelated image sensors have been widely used in diverse optical measurement fields.With unavoidable imaging noise,there is a precision limit(PL)when estimating the target positions on image sensors,which depends on the detected photon count,noise,point spread function(PSF)radius,and PSF’s intra-pixel position.Previous studies have clearly reported the effects of the first three parameters on the PL but have neglected the intra-pixel position information.Here,we develop a localization PL analysis framework for revealing the effect of the intra-pixel position of small PSFs.To accurately estimate the PL in practical applications,we provide effective PSF(e PSF)modeling approaches and apply the Cramér–Rao lower bound.Based on the characteristics of small PSFs,we first derive simplified equations for finding the best PL and the best intra-pixel region for an arbitrary small PSF;we then verify these equations on real PSFs.Next,we use the typical Gaussian PSF to perform a further analysis and find that the final optimum of the PL is achieved at the pixel boundaries when the Gaussian radius is as small as possible,indicating that the optimum is ultimately limited by light diffraction.Finally,we apply the maximum likelihood method.Its combination with e PSF modeling allows us to successfully reach the PL in experiments,making the above theoretical analysis effective.This work provides a new perspective on combining image sensor position control with PSF engineering to make full use of information theory,thereby paving the way for thoroughly understanding and achieving the final optimum of the PL in optical localization.展开更多
This paper addresses a critical challenge in the design of MEMS actuators:the rejection of out-of-plane motion,specifically along the Z-axis,which can severely impact the precision and performance of these micro-actua...This paper addresses a critical challenge in the design of MEMS actuators:the rejection of out-of-plane motion,specifically along the Z-axis,which can severely impact the precision and performance of these micro-actuation systems.In many MEMS applications,unwanted out-of-plane displacement can lead to reduced accuracy in tasks such as optical steering,micro-manipulation,and scanning applications.In response to these limitations,this paper proposes a novel design technique that effectively rejects Z-axis motion by transforming the motion of the micro stage along the Z-axis into equivalent displacements between pairs of points on cantilevers.These point pairs are founded exhibiting variable common-mode and differential-mode motion characteristics,depending on whether the stage is undergoing in-plane(X/Y)or out-of-plane(Z)displacements.By connecting these point pairs with rods,differential motion between the points in the pairs is suppressed,reducing unwanted out-of-plane motion significantly.We provide a detailed analysis of this design methodology and present a practical application in the form of an electromagnetic large displacement MEMS actuator.This actuator undergoes a complete design-simulationmanufacturing-testing cycle,where the effectiveness of the Z-axis motion rejection structure is systematically evaluated,and compared against traditional designs.Experimental results reveal a significant improvement in performance,with static and dynamic travel ranges reaching±60μm and±400μm,respectively.Moreover,the Z-axis stiffness was enhanced by 68.5%,which is more than five times the improvement observed in the X/Y axes’stiffness.These results highlight the potential of the proposed method to provide a robust solution for out-of-plane motion suppression in MEMS actuators,offering improved performance without compromising other critical parameters such as displacement and actuation speed.展开更多
Light detection and ranging(LiDAR)is widely used for active three-dimensional(3D)perception.Beam scanning LiDAR provides high accuracy and long detection range with limited detection efficiency,while flash LiDAR can a...Light detection and ranging(LiDAR)is widely used for active three-dimensional(3D)perception.Beam scanning LiDAR provides high accuracy and long detection range with limited detection efficiency,while flash LiDAR can achieve high-efficiency detection through the snapshot approach at the expense of reduced accuracy and range.With the synergy of these distinct detection approaches,we develop a miniaturized dual-mode,reconfigurable beam forming device by cascading Pancharatnam-Berry phase and propagation phase metasurfaces,integrated with a microactuator.By modulating incident light polarization,we can switch the output beam of the device between the beam array scanning mode and flash illuminating mode.In the scanning mode,the device demonstrates a continuously tunable angular resolution and a±35°field of view(FoV)through driving the micro-actuator to achieve the lateral translation of±100μm.In the flash mode,uniform illumination across the entire FoV is achieved.As a proof of concept,we propose an adaptive 3D reconstruction scheme that leverages the device’s capability to switch operation modes and adjust detection resolution.Together,the proposed device and the detection scheme constitute a dualmode LiDAR system,demonstrating high adaptability to diverse environments and catalyze the applications of more efficient and compact 3D detection systems.展开更多
A nickel/photoredox mediated asymmetric domino alkyl arylation of vinyl phosphonates to generate a diverse array of enantioenrichedα-aryl phosphonates is disclosed.This asymmetric three-component difunctionalization ...A nickel/photoredox mediated asymmetric domino alkyl arylation of vinyl phosphonates to generate a diverse array of enantioenrichedα-aryl phosphonates is disclosed.This asymmetric three-component difunctionalization couples aryl halides and alkyl bromides with vinyl phosphonates,exhibiting excellent chemo-and regioselectivity under mild reaction conditions.The method avoids the need for pre-formed organometallics and phosphorus halides.Mechanistic and DFT studies suggest that photoexcited[4CzIPN]*oxidizes diethyl 1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylate(HEH)to generate the[4CzIPN]■-,which then reduces the alkyl bromide to form alkyl radicals that undergo Giese addition to the vinyl phosphonate.At the same time,Ni0 oxidatively adds the aryl bromide followed by enantiodetermining oxidative radical trapping of the phosphonate-based radical by the tetrahedral Ni^(Ⅱ) center followed by reductive elimination.Independent gradient model based on Hirshfeld partition(IGMH)analysis suggests that the orientation of the phosphonate group(P=-O…πinteraction)is expected to play an essential role in controlling the enantioselectivity.展开更多
Uncontrolled hemorrhage remains the leading cause of death in clinical and emergency care,posing a major threat to human life.To achieve effective bleeding control,many hemostatic materials have emerged.Among them,nat...Uncontrolled hemorrhage remains the leading cause of death in clinical and emergency care,posing a major threat to human life.To achieve effective bleeding control,many hemostatic materials have emerged.Among them,nature-derived biopolymers occupy an important position due to the excellent inherent biocompatibility,biodegradability and bioactivity.Additionally,sponges have been widely used in clinical and daily life because of their rapid blood absorption.Therefore,we provide the overview focusing on the latest advances and smart designs of biopolymer-based hemostatic sponge.Starting from the component,the applications of polysaccharide and polypeptide in hemostasis are systematically introduced,and the unique bioactivities such as antibacterial,antioxidant and immunomodulation are also concerned.From the perspective of sponge structure,different preparation processes can obtain unique physical properties and structures,which will affect the material properties such as hemostasis,antibacterial and tissue repair.Notably,as development frontier,the multifunctions of hemostatic materials is summarized,mainly including enhanced coagulation,antibacterial,avoiding tumor recurrence,promoting tissue repair,and hemorrhage monitoring.Finally,the challenges facing the development of biopolymer-based hemostatic sponges are emphasized,and future directions for in vivo biosafety,emerging materials,multiple application scenarios and translational research are proposed.展开更多
A small and weak target detection method is proposed in this work that outperforms all other methods in terms of real-time capability.It is the first time that two-dimensional(2D)images are processed using only one-di...A small and weak target detection method is proposed in this work that outperforms all other methods in terms of real-time capability.It is the first time that two-dimensional(2D)images are processed using only one-dimensional1D structuring elements in a morphology-based approach,enabling the real-time hardware implementation of the whole image processing method.A parallel image readout and processing structure is introduced to achieve an ultra-low latency time on the order of nanoseconds,and a hyper-frame resolution in the time domain can be achieved by combining the row-by-row structure and the electrical rolling shutter technique.Experimental results suggest that the expected target can be successfully detected under various interferences with an accuracy of 0.1 pixels(1σ)under the worst sky night test condition and that a centroiding precision of better than 0.03 pixels(1σ)can be reached for static tests.The real-time detection method with high robustness and accuracy is attractive for application to all types of real-time small target detection systems,such as medical imaging,infrared surveillance,and target measurement and tracking,where an ultra-high processing speed is required.展开更多
Graphene mesh electrodes （GMEs） with good conductivity and transparency have been fabricated by the standard industrial photolithography and 02 plasma etching process using graphene solutions. Organic photovoltaic ...Graphene mesh electrodes （GMEs） with good conductivity and transparency have been fabricated by the standard industrial photolithography and 02 plasma etching process using graphene solutions. Organic photovoltaic （OPV） cells using GMEs as the transparent electrodes with a blend of poly-（3-hexylthiophene） phenyl-C61-butyric acid methyl ester （P3HT/PC61BM） as the active layer have been fabricated and exhibit a power conversion efficiency （PCE） of 2.04%, the highest PCE for solution-processed graphene transparent electrode-based solar cells reported to date.展开更多
Cell-based tissue engineering is one of the optimistic approaches to replace current treatments for bone defects.Urine-derived stem cells(USCs)are obtained non-invasively and become one of the promising seed cells for...Cell-based tissue engineering is one of the optimistic approaches to replace current treatments for bone defects.Urine-derived stem cells(USCs)are obtained non-invasively and become one of the promising seed cells for bone regeneration.An injectable BMP2-releasing chitosan microspheres/type I collagen hydrogel(BMP2-CSM/Col I hydrogel)was fabricated.USCs proliferated in a time-dependent fashion,spread with good extension and interconnected with each other in different hydrogels both for 2D and 3D models.BMP2 was released in a sustained mode for more than 28 days.Sustained-released BMP2 increased the ALP activities and mineral depositions of USCs in 2D culture,and enhanced the expression of osteogenic genes and proteins in 3D culture.In vivo,the mixture of USCs and BMP2-CSM/Col I hydrogels effectively enhanced bone regeneration,and the ratio of new bone volume to total bone volume was 38%after 8weeks of implantation.Our results suggested that BMP2-CSM/Col I hydrogels promoted osteogenic differentiation of USCs in 2D and 3D culture in vitro and USCs provided a promising cell source for bone tissue engineering in vivo.As such,USCs-seeded hydrogel scaffolds are regarded as an alternative approach in the repair of bone defects.展开更多
基金supported in part by the National Key R&D Program of China Grant 2022YFB4602200.
文摘With the intelligent upgrading of manufacturing equipment,achieving high-precision and efficient fault diagnosis is essential to enhance equipment stability and increase productivity.Online monitoring and fault diagnosis technology play a critical role in improving the stability of metal additive manufacturing equipment.However,the limited proportion of fault data during operation challenges the accuracy and efficiency of multi-classification models due to excessive redundant data.A multi-sensor and principal component analysis(PCA)and support vector machine(SVM)asymptotic classification(PCSV)for additive manufacturing fault diagnosis method is proposed,and it divides the fault diagnosis into two steps.In the first step,real-time data are evaluated using the T2 and Q statistical parameters of the PCAmodel to identify potential faults while filtering non-fault data,thereby reducing redundancy and enhancing real-time efficiency.In the second step,the identified fault data are input into the SVM model for precise multi-class classification of fault categories.The PCSV method advances the field by significantly improving diagnostic accuracy and efficiency,achieving an accuracy of 99%,a diagnosis time of 0.65 s,and a training time of 503 s.The experimental results demonstrate the sophistication of the PCSV method for high-precision and high-efficiency fault diagnosis of small fault samples.
文摘Voxel-based morphometry has been used in the study of alterations in brain structure in type 1 diabetes mellitus patients. These changes are associated with clinical indices. The age at onset, pathogenesis, and treatment of type 1 diabetes mellitus are different from those for type 2 diabetes mellitus. Thus, type 1 and type 2 diabetes mellitus may have different impacts on brain structure. Only a few studies of the alterations in brain structure in type 2 diabetes mellitus patients using voxel-based morphometry have been conducted, with inconsistent results. We detected subtle changes in the brain structure of 23 cases of type 2 diabetes mellitus, and demonstrated that there was no significant difference between the total volume of gray and white matter of the brain of type 2 diabetes mellitus patients and that in controls. Regional atrophy of gray matter mainly occurred in the right temporal and left occipital cortex, while regional atrophy of white matter involved the right temporal lobe and the right cerebellar hemisphere. The ankle-brachial index in patients with type 2 diabetes mellitus strongly correlated with the volume of brain regions in the default mode network. The ankle-brachial index, followed by the level of glycosylated hemoglobin, most strongly correlated with the volume of gray matter in the right temporal lobe. These data suggest that voxel-based morphometry could detect small structural changes in patients with type 2 diabetes mellitus. Early macrovascular atherosclerosis may play a crucial role in subtle brain atro- phy in type 2 diabetes mellitus patients, with chronic hyperglycemia playing a lesser role.
基金supported by the National Natural Science Foundation of China(31870961,81501879)the Sino-German Center for Research Promotion(GZ1219)+1 种基金the International Cooperation Project of the Science and Technology Department of Sichuan Province(Grant No.2015HH0049,No.2017SZ0127,No.2020YFS0140)the National Clinical Research Center for Geriatrics,West China Hospital,Sichuan University(Z2018A11)。
文摘Traditional orthopedic metal implants,such as titanium(Ti),Ti alloys,and cobalt-chromium(Co-Cr)alloys,cannot be degraded in vivo.Fracture patients is must always suffer a second operation to remove the implants.Moreover,stress shielding,or stress protection occurs when traditional orthopedic metal implants are applied in fractures surgery.The mechanical shunt produced by traditional orthopedic metal implants can cause bone loss over time,resulting in decreased bone strength and delayed fracture healing.Biodegradable metals that‘biocorrode’are currently attracting significant interest in the orthopedics field due to their suitability as temporary implants.As one of the biodegradable metals,magnesium(Mg)and Mg alloys have gained interest in the field of medicine due to their low density,excellent biocompatibility,high bioresorbability,and proper mechanical properties.Additionally,Mg ions released from the metal implants can promote osteogenesis and angiogenesis during the degradation process in vivo,which is substantially better for orthopedic fixation than other bioinert metal materials.Therefore,this review focuses on the properties,fabrication,biological functions,and surface modification of Mg-based alloys as novel bioabsorbable biomaterials for orthopedic applications.
基金This work was supported by the National Key Research and Development Program of China(No.18YFB1105600,2018YFC1106800)National Natural Science Foundation of China(51875518)+1 种基金Sichuan Province Science&Technology Department Projects(2016CZYD0004,2017SZ0001,2018GZ0142,2019YFH0079)Research Foundation for Young Teachers of Sichuan University(2018SCUH0017)and The“111”Project(No.B16033).
文摘The bone regenerative scaffold with the tailored degradation rate matching with the growth rate of the new bone is essential for adolescent bone repair.To satisfy these requirement,we proposed bone tissue scaffolds with controlled degradation rate using osteoinductive materials(Ca-P bioceramics),which is expected to present a controllable biodegradation rate for patients who need bone regeneration.Physicochemical properties,porosity,compressive strength and degradation properties of the scaffolds were studied.3D printed Ca-P scaffold(3DS),gas foaming Ca-P scaffold(FS)and autogenous bone(AB)were used in vivo for personalized beagle skull defect repair.Histological results indicated that the 3DS was highly vascularized and well combined with surrounding tissues.FS showed obvious newly formed bone tissues.AB showed the best repair effect,but it was found that AB scaffolds were partially absorbed and degraded.This study indicated that the 3D printed Ca-P bioceramics with tailored biodegradation rate is a promising candidate for personalized skull bone tissue reconstruction.
基金Project supported by the National Natural Science Foundation of China(11474078)。
文摘The multilayered structure thin films(Gd_(2)(MoO_(4))_(3):Ho(Tm)/Yb@Gd_(2)(MoO_(4))_(3):Yb) were prepared through sol-gel and spin-coating method,while the average thinness was nearly 140 nm.We investigated the up-conversion luminescence of Gd_(2)(MoO_(4))_(3):Ho(Tm)/Yb@Gd_(2)(MoO_(4))_(3):Yb thin films,The results show that the double-layer structured thin films are able to increase the emission intensity.The fluorescence enhancement factors of the luminescence from Gd_(2)(MoO_(4))_(3):Ho/Yb@Gd_(2)(MoO_(4))_(3):Yb thin films,located at540 and 662 nm,reach 7.5 and 4.3,respectively.And the enhancement factors of emissions located at450,475 and 650 nm(Gd_(2)(MoO_(4))_(3):Tm/Yb@Gd_(2)(MoO_(4))_(3):Yb) reach 9,2 and 2,respectively.The considerable enhancement is due to the suppression of surface quenching and energy harvesting via the Yb ions in the outer shell.In addition,the emission color of thin films can be modulated from yellow to blue via tuning the number of Gd_(2)(MoO_(4))_(3):Ho/Yb and Gd_(2)(MoO_(4))_(3):Tm/Yb layers,which provides a feasible strategy to tune the up-conversion emission color.
基金supported by the National Natural Science Foundation of China(Grant No.61505109)Youth Innovative Talents Attracting and Cultivating Plan of Colleges and Universities in Shandong Province(No.21)+1 种基金Youth Innovation Team of colleges and universities in Shandong Province(Grant No.2022KJ223)Shandong Provincial Natural Science Foundation(Grant No.ZR2021QF020).
文摘The anisotropic properties and applications ofβ-gallium oxide(β-Ga_(2)O_(3))are comprehensively reviewed.All the anisotropic properties are essentially resulted from the anisotropic crystal structure.The process flow of how to exfoliate nanoflakes from bulk material is introduced.Anisotropic optical properties,including optical bandgap,Raman and photolumines-cence characters are comprehensively reviewed.Three measurement configurations of angle-resolved polarized Raman spec-tra(ARPRS)are reviewed,with Raman intensity formulas calculated with Raman tensor elements.The method to obtain the Raman tensor elements of phonon modes through experimental fitting is also introduced.In addition,the anisotropy in elec-tron mobility and affinity are discussed.The applications,especially polarization photodetectors,based onβ-Ga_(2)O_(3)were summa-rized comprehensively.Three kinds of polarization detection mechanisms based on material dichroism,1D morphology and metal-grids are discussed in-depth.This review paper provides a framework for anisotropic optical and electric properties ofβ-Ga_(2)O_(3),as well as the applications based on these characters,and is expected to lead to a wider discussion on this topic.
基金the support from the National Natural Science Foundation of China(51827806)the National Key Research and Development Program of China(2016YFB0501201)the Xplorer Prize funded by the Tencent Foundation。
文摘Subpixel localization techniques for estimating the positions of point-like images captured by pixelated image sensors have been widely used in diverse optical measurement fields.With unavoidable imaging noise,there is a precision limit(PL)when estimating the target positions on image sensors,which depends on the detected photon count,noise,point spread function(PSF)radius,and PSF’s intra-pixel position.Previous studies have clearly reported the effects of the first three parameters on the PL but have neglected the intra-pixel position information.Here,we develop a localization PL analysis framework for revealing the effect of the intra-pixel position of small PSFs.To accurately estimate the PL in practical applications,we provide effective PSF(e PSF)modeling approaches and apply the Cramér–Rao lower bound.Based on the characteristics of small PSFs,we first derive simplified equations for finding the best PL and the best intra-pixel region for an arbitrary small PSF;we then verify these equations on real PSFs.Next,we use the typical Gaussian PSF to perform a further analysis and find that the final optimum of the PL is achieved at the pixel boundaries when the Gaussian radius is as small as possible,indicating that the optimum is ultimately limited by light diffraction.Finally,we apply the maximum likelihood method.Its combination with e PSF modeling allows us to successfully reach the PL in experiments,making the above theoretical analysis effective.This work provides a new perspective on combining image sensor position control with PSF engineering to make full use of information theory,thereby paving the way for thoroughly understanding and achieving the final optimum of the PL in optical localization.
基金the National Natural Science Foundation of China(Grant No.U21A6003&Grant No.U24A6006).
文摘This paper addresses a critical challenge in the design of MEMS actuators:the rejection of out-of-plane motion,specifically along the Z-axis,which can severely impact the precision and performance of these micro-actuation systems.In many MEMS applications,unwanted out-of-plane displacement can lead to reduced accuracy in tasks such as optical steering,micro-manipulation,and scanning applications.In response to these limitations,this paper proposes a novel design technique that effectively rejects Z-axis motion by transforming the motion of the micro stage along the Z-axis into equivalent displacements between pairs of points on cantilevers.These point pairs are founded exhibiting variable common-mode and differential-mode motion characteristics,depending on whether the stage is undergoing in-plane(X/Y)or out-of-plane(Z)displacements.By connecting these point pairs with rods,differential motion between the points in the pairs is suppressed,reducing unwanted out-of-plane motion significantly.We provide a detailed analysis of this design methodology and present a practical application in the form of an electromagnetic large displacement MEMS actuator.This actuator undergoes a complete design-simulationmanufacturing-testing cycle,where the effectiveness of the Z-axis motion rejection structure is systematically evaluated,and compared against traditional designs.Experimental results reveal a significant improvement in performance,with static and dynamic travel ranges reaching±60μm and±400μm,respectively.Moreover,the Z-axis stiffness was enhanced by 68.5%,which is more than five times the improvement observed in the X/Y axes’stiffness.These results highlight the potential of the proposed method to provide a robust solution for out-of-plane motion suppression in MEMS actuators,offering improved performance without compromising other critical parameters such as displacement and actuation speed.
基金supported by National Natural Science Foundation of China(Grant No.U21A6003)National Key Research and Development Program of China(Grant No.2023YFB3906300)+1 种基金support from the Beijing Outstanding Young Scientist Program(Grant No.JWZQ20240101028)support from National Natural Science Foundation of China(Grant No.62475018).
文摘Light detection and ranging(LiDAR)is widely used for active three-dimensional(3D)perception.Beam scanning LiDAR provides high accuracy and long detection range with limited detection efficiency,while flash LiDAR can achieve high-efficiency detection through the snapshot approach at the expense of reduced accuracy and range.With the synergy of these distinct detection approaches,we develop a miniaturized dual-mode,reconfigurable beam forming device by cascading Pancharatnam-Berry phase and propagation phase metasurfaces,integrated with a microactuator.By modulating incident light polarization,we can switch the output beam of the device between the beam array scanning mode and flash illuminating mode.In the scanning mode,the device demonstrates a continuously tunable angular resolution and a±35°field of view(FoV)through driving the micro-actuator to achieve the lateral translation of±100μm.In the flash mode,uniform illumination across the entire FoV is achieved.As a proof of concept,we propose an adaptive 3D reconstruction scheme that leverages the device’s capability to switch operation modes and adjust detection resolution.Together,the proposed device and the detection scheme constitute a dualmode LiDAR system,demonstrating high adaptability to diverse environments and catalyze the applications of more efficient and compact 3D detection systems.
基金the National Natural Science Foundation of China(No.22071107)Natural Science Foundation of Jiangsu Province,China(No.BK20211588 and No.BK20220328)+2 种基金Natural Science Research Projects of Colleges and Universities in Jiangsu Province(No.22KJB150005)Jiangsu Excellent Postdoctoral Program(No.287706)the US NSF(No.CHE-2154593).
文摘A nickel/photoredox mediated asymmetric domino alkyl arylation of vinyl phosphonates to generate a diverse array of enantioenrichedα-aryl phosphonates is disclosed.This asymmetric three-component difunctionalization couples aryl halides and alkyl bromides with vinyl phosphonates,exhibiting excellent chemo-and regioselectivity under mild reaction conditions.The method avoids the need for pre-formed organometallics and phosphorus halides.Mechanistic and DFT studies suggest that photoexcited[4CzIPN]*oxidizes diethyl 1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylate(HEH)to generate the[4CzIPN]■-,which then reduces the alkyl bromide to form alkyl radicals that undergo Giese addition to the vinyl phosphonate.At the same time,Ni0 oxidatively adds the aryl bromide followed by enantiodetermining oxidative radical trapping of the phosphonate-based radical by the tetrahedral Ni^(Ⅱ) center followed by reductive elimination.Independent gradient model based on Hirshfeld partition(IGMH)analysis suggests that the orientation of the phosphonate group(P=-O…πinteraction)is expected to play an essential role in controlling the enantioselectivity.
基金jointly sponsored by Sichuan Science and Tech-nology Program(2024NSFSC0002 and MZGC20240011)“1.3.5”Project for Disciplines of Excellence,West China Hospital,Sichuan University(ZYGD23037)+1 种基金the Frontiers Medical Center,Tianfu Jincheng Laboratory Foundation(TFJC2023010002)the National Natural Science Foundation of China(Grant No.32171351).
文摘Uncontrolled hemorrhage remains the leading cause of death in clinical and emergency care,posing a major threat to human life.To achieve effective bleeding control,many hemostatic materials have emerged.Among them,nature-derived biopolymers occupy an important position due to the excellent inherent biocompatibility,biodegradability and bioactivity.Additionally,sponges have been widely used in clinical and daily life because of their rapid blood absorption.Therefore,we provide the overview focusing on the latest advances and smart designs of biopolymer-based hemostatic sponge.Starting from the component,the applications of polysaccharide and polypeptide in hemostasis are systematically introduced,and the unique bioactivities such as antibacterial,antioxidant and immunomodulation are also concerned.From the perspective of sponge structure,different preparation processes can obtain unique physical properties and structures,which will affect the material properties such as hemostasis,antibacterial and tissue repair.Notably,as development frontier,the multifunctions of hemostatic materials is summarized,mainly including enhanced coagulation,antibacterial,avoiding tumor recurrence,promoting tissue repair,and hemorrhage monitoring.Finally,the challenges facing the development of biopolymer-based hemostatic sponges are emphasized,and future directions for in vivo biosafety,emerging materials,multiple application scenarios and translational research are proposed.
基金support by the China NSF projects(Nos.61505094,61377012 and 51522505).
文摘A small and weak target detection method is proposed in this work that outperforms all other methods in terms of real-time capability.It is the first time that two-dimensional(2D)images are processed using only one-dimensional1D structuring elements in a morphology-based approach,enabling the real-time hardware implementation of the whole image processing method.A parallel image readout and processing structure is introduced to achieve an ultra-low latency time on the order of nanoseconds,and a hyper-frame resolution in the time domain can be achieved by combining the row-by-row structure and the electrical rolling shutter technique.Experimental results suggest that the expected target can be successfully detected under various interferences with an accuracy of 0.1 pixels(1σ)under the worst sky night test condition and that a centroiding precision of better than 0.03 pixels(1σ)can be reached for static tests.The real-time detection method with high robustness and accuracy is attractive for application to all types of real-time small target detection systems,such as medical imaging,infrared surveillance,and target measurement and tracking,where an ultra-high processing speed is required.
文摘Graphene mesh electrodes （GMEs） with good conductivity and transparency have been fabricated by the standard industrial photolithography and 02 plasma etching process using graphene solutions. Organic photovoltaic （OPV） cells using GMEs as the transparent electrodes with a blend of poly-（3-hexylthiophene） phenyl-C61-butyric acid methyl ester （P3HT/PC61BM） as the active layer have been fabricated and exhibit a power conversion efficiency （PCE） of 2.04%, the highest PCE for solution-processed graphene transparent electrode-based solar cells reported to date.
基金supported by National Natural Science Foundation of China[31870961,81874027]Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions[312200102]+3 种基金Science&Technology Department of Sichuan Province[2020YFS0140,2021YFSY0003]Health Commission of Sichuan Province[19PJ104]Clinical Research Incubation project of West China Hospital of Sichuan University[2019HXFH041,2021HXFH036]the‘1.3.5 Program for Disciplines of Excellence’West China Hospital,Sichuan University。
文摘Cell-based tissue engineering is one of the optimistic approaches to replace current treatments for bone defects.Urine-derived stem cells(USCs)are obtained non-invasively and become one of the promising seed cells for bone regeneration.An injectable BMP2-releasing chitosan microspheres/type I collagen hydrogel(BMP2-CSM/Col I hydrogel)was fabricated.USCs proliferated in a time-dependent fashion,spread with good extension and interconnected with each other in different hydrogels both for 2D and 3D models.BMP2 was released in a sustained mode for more than 28 days.Sustained-released BMP2 increased the ALP activities and mineral depositions of USCs in 2D culture,and enhanced the expression of osteogenic genes and proteins in 3D culture.In vivo,the mixture of USCs and BMP2-CSM/Col I hydrogels effectively enhanced bone regeneration,and the ratio of new bone volume to total bone volume was 38%after 8weeks of implantation.Our results suggested that BMP2-CSM/Col I hydrogels promoted osteogenic differentiation of USCs in 2D and 3D culture in vitro and USCs provided a promising cell source for bone tissue engineering in vivo.As such,USCs-seeded hydrogel scaffolds are regarded as an alternative approach in the repair of bone defects.
