Predicting the performance of a tunneling boring machine is vitally important to avoid any possible accidents during tunneling boring.The prediction is not straightforward due to the uncertain geological conditions an...Predicting the performance of a tunneling boring machine is vitally important to avoid any possible accidents during tunneling boring.The prediction is not straightforward due to the uncertain geological conditions and the complex rock-machine interactions.Based on the big data obtained from the 72.1 km long tunnel in the Yin-Song Diversion Project in China,this study developed a machine learning model to predict the TBM performance in a real-time manner.The total thrust and the cutterhead torque during a stable period in a boring cycle was predicted in advance by using the machine-returned parameters in the rising period.A long short-term memory model was developed and its accuracy was evaluated.The results show that the variation in the total thrust and cutterhead torque with various geological conditions can be well reflected by the proposed model.This real-time predication shows superior performance than the classical theoretical model in which only a single value can be obtained based on the single measurement of the rock properties.To improve the accuracy of the model a filtering process was proposed.Results indicate that filtering the unnecessary parameters can enhance both the accuracy and the computational efficiency.Finally,the data deficiency was discussed by assuming a parameter was missing.It is found that the missing of a key parameter can significantly reduce the accuracy of the model,while the supplement of a parameter that highly-correlated with the missing one can improve the prediction.展开更多
Landslide identification is critical for risk assessment and mitigation.This paper proposes a novel machinelearning and deep-learning method to identify natural-terrain landslides using integrated geodatabases.First,l...Landslide identification is critical for risk assessment and mitigation.This paper proposes a novel machinelearning and deep-learning method to identify natural-terrain landslides using integrated geodatabases.First,landslide-related data are compiled,including topographic data,geological data and rainfall-related data.Then,three integrated geodatabases are established;namely,Recent Landslide Database(Rec LD),Relict Landslide Database(Rel LD)and Joint Landslide Database(JLD).After that,five machine learning and deep learning algorithms,including logistic regression(LR),support vector machine(SVM),random forest(RF),boosting methods and convolutional neural network(CNN),are utilized and evaluated on each database.A case study in Lantau,Hong Kong,is conducted to demonstrate the application of the proposed method.From the results of the case study,CNN achieves an identification accuracy of 92.5%on Rec LD,and outperforms other algorithms due to its strengths in feature extraction and multi dimensional data processing.Boosting methods come second in terms of accuracy,followed by RF,LR and SVM.By using machine learning and deep learning techniques,the proposed landslide identification method shows outstanding robustness and great potential in tackling the landslide identification problem.展开更多
Color metasurface holograms are powerful and versatile platforms for modulating the amplitude,phase,polarization,and other properties of light at multiple operating wavelengths.However,the current color metasurface ho...Color metasurface holograms are powerful and versatile platforms for modulating the amplitude,phase,polarization,and other properties of light at multiple operating wavelengths.However,the current color metasurface holography can only realize static manipulation.In this study,we propose and demonstrate a multiplexing metasurface technique combined with multiwavelength code-division multiplexing(CDM)to realize dynamic manipulation.Multicolor code references are utilized to record information within a single metasurface and increase the information capacity and security for anticracks.A total of 48 monochrome images consisting of pure color characters and multilevel color video frames were reconstructed in dual polarization channels of the birefringent metasurface to exhibit high information density,and a video was displayed via sequential illumination of the corresponding code patterns to verify the ability of dynamic manipulation.Our approach demonstrates significant application potential in optical data storage,optical encryption,multiwavelengthversatile diffractive optical elements,and stimulated emission depletion microscopy.展开更多
Landslides represent major threats to life and property in many areas of the world,such as the landslides in the Three Gorges Dam area in China's Mainland.To better prepare for landslides in this area,we explored ...Landslides represent major threats to life and property in many areas of the world,such as the landslides in the Three Gorges Dam area in China's Mainland.To better prepare for landslides in this area,we explored how several machine learning algorithms(long short term memory(LSTM),random forest(RF),and gated recurrent unit(GRU))might predict ground displacements under three types of landslides,each with distinct step-wise displacement characteristics.Landslide displacements are described with trend and periodic analyses and the predictions with each algorithm,validated with observations from the Three Gorges Dam reservoir over a one-year period.Results demonstrated that deep machine learning algorithms can be valuable tools for predicting landslide displacements,with the LSTM and GRU algorithms providing the most encouraging results.We recommend using these algorithms to predict landslide displacement of step-wise type landslides in the Three Gorges Dam area.Predictive models with similar reliability should gradually become a component when implementing early warning systems to reduce landslide risk.展开更多
Aqueous Zinc-ion batteries(ZIB) are attracting immense attention because of their merits of excellent safety and quite cheap properties compared with lithium-ion batteries(LIB).Manganese oxide is one of the most impor...Aqueous Zinc-ion batteries(ZIB) are attracting immense attention because of their merits of excellent safety and quite cheap properties compared with lithium-ion batteries(LIB).Manganese oxide is one of the most important cathode materials of ZIB.In this paper,α-Mn2O3 used as cathode of ZIB is synthesized via Metal-Organic Framework(MOF)-derived method,which delivers a high specific capacity of225 mAh g^(-1) at 0.05 A g^(-1) and 92.7 mAh g^(-1) after 1700 cycles at 2 A g^(-1).The charge storage mechanism of α-Mn2O3 cathode is found to greatly depend on the discharge current density.At lower current density discharging,the H+ and Zn2+ are successively intercalated into the α-Mn2O3 before and after the "turning point" of discharge voltage and their discharging products present obviously different morphologies changing from flower-like to large plate-like products.At a higher current density,the low-voltage plateau after the turning point disappears due to the decrease of amount of Zn2+ intercalation and the H+intercalation is dominated in α-Mn2 O3.This study provides significant understanding for future design and research of high-performance Mn-based cathodes of ZIB.展开更多
In this work,on-chip chalcogenide glass photonic integrations with several fundamental photonic building blocks are designed and fabricated based on the As2 S3 platform for improved 2μm optical interconnection,achiev...In this work,on-chip chalcogenide glass photonic integrations with several fundamental photonic building blocks are designed and fabricated based on the As2 S3 platform for improved 2μm optical interconnection,achieving a broadened wavelength bandwidth and improved fabrication tolerance.A 600 nm thick As2 S3 strip waveguide has low propagation loss of 1.447 dB/cm at 2μm.Broadband vertical coupling is realized by a grating coupler with 4.3 dB coupling loss.A Bragg grating filter,power splitter,Mach–Zander interferometer,and mode converter for on-chip mode division multiplexing(MDM)are also reported at 2μm with reliable performances.Finally,a record high MDM optical interconnection capacity of 3×80 Gbps at 2μm is experimentally demonstrated based on the proposed As2 S3 chip,drawing promising prospects for future photonic integration and high-speed interconnection at the 2μm waveband.展开更多
Real-time wireless respiratory monitoring and biomarker analysis provide an attractive vision for noninvasive telemedicine such as the timely prevention of respiratory arrest or for early diagnoses of chronic diseases...Real-time wireless respiratory monitoring and biomarker analysis provide an attractive vision for noninvasive telemedicine such as the timely prevention of respiratory arrest or for early diagnoses of chronic diseases.Lightweight,wearable respiratory sensors are in high demand as they meet the requirement of portability in digital healthcare management.Meanwhile,high-performance sensing material plays a crucial role for the precise sensing of specific markers in exhaled air,which represents a complex and rather humid environment.Here,we present a liquid metal-based flexible electrode coupled with SnS_(2)nanomaterials as a wearable gas-sensing device,with added Bluetooth capabilities for remote respiratory monitoring and diagnoses.The flexible epidermal device exhibits superior skin compatibility and high responsiveness(1092%/ppm),ultralow detection limits(1.32 ppb),and a good selectivity of NO gas at ppb-level concentrations.Taking advantage of the fast recovery kinetics of SnS_(2)responding to H_(2)O molecules,it is possible to accurately distinguish between different respiratory patterns based on the amount of water vapor in the exhaled air.Furthermore,based on the different redox types of H_(2)O and NO molecules,the electric signal is reversed once the exhaled NO concentration exceeds a certain threshold that may indicate the onset of conditions like asthma,thus providing an early warning system for potential lung diseases.Finally,by integrating the wearable device into a wireless cloud-based multichannel interface,we provide a proof-of-concept that our device could be used for the simultaneous remote monitoring of several patients with respiratory diseases,a crucial field in future digital healthcare management.展开更多
Biochar(BC)are widely used as highly efficient adsorbents to alleviate aromatics-based contaminants due to their ease of preparation,wide availability,and high sustainability.The surface properties of BCs usually vary...Biochar(BC)are widely used as highly efficient adsorbents to alleviate aromatics-based contaminants due to their ease of preparation,wide availability,and high sustainability.The surface properties of BCs usually vary greatly due to their complex chemical constituents and different preparation processes and are reflected in the values of parameters such as the specific surface area(SSA),pore volume/size,and surface functional groups(SFGs).The effects of SSA and pore volume/size on the adsorption of aromatics have been widely reported.However,the corresponding mechanisms of BC SFGs towards aromatics adsorption remains unclear as the compositions of the SFGs are usually complex and hard to determine.To address in this gap in the literature,this review introduces a new perspective on the adsorption mechanisms of aromatics.Through collecting previously-reported results,the parameters log P(logarithm of the Kow),polar surface area,and the positive/negative charges were carefully calculated using Chem Draw3D,which allowed the hydrophobicity/hydrophilicity properties,electron donor-acceptor interactions,Hbonding,and electrostatic interactions between SFGs and aromatics-based contaminates to be inferred intuitively.These predictions were consistent with the reported results and showed that tailor-made BCs can be designed according to the molecular weights,chemical structures,and polarities of the target aromatics.Overall,this review provides new insight into predicting the physicochemical properties of BCs through revealing the relationship between SFGs and adsorbates,which may provide useful guidance for the preparing of highly-efficient,functional BCs for the adsorption of aromatics.展开更多
Surface-enhanced Raman spectroscopy(SERS),as a highly sensitive molecular analysis technique,can realize fast and non-destructive detection of the information of molecular bonds to identify the component of analytes b...Surface-enhanced Raman spectroscopy(SERS),as a highly sensitive molecular analysis technique,can realize fast and non-destructive detection of the information of molecular bonds to identify the component of analytes by"fingerprint"identification.The preparation of SERS substrates plays an extremely important role in the development of SERS technology and the application of SERS detection.By integrating SERS enhancement substrates into microfluidic chips,researchers have developed the microfluidic SERS chips which expand the function of microfluidic chips and provide an efficient platform for on-site biochemical analysis equipped with the powerful sensing capability of SERS technique.In this paper,we will first briefly give a review of the current microfluidic SERS-active substrates preparation technology and present the perspective on the application prospects of microfluidic SERS-active substrates.And then the challenges in the preparation of microfluidic SERS-active substrates will be pointed out,as well as realistic issues of using this technology for biochemical application.展开更多
The polymer electrolyte membrane(PEM)electrolyzers are burdened with costly iridium(Ir)-based catalysts and high operation overpotentials for the oxygen evolution reaction(OER).The development of earth-abundant,highly...The polymer electrolyte membrane(PEM)electrolyzers are burdened with costly iridium(Ir)-based catalysts and high operation overpotentials for the oxygen evolution reaction(OER).The development of earth-abundant,highly active,and durable electrocatalysts to replace Ir is a critical step in reducing the cost of green hydrogen production.Here we develop a Ru5Mo4Ox binary oxide catalyst that exhibits high activity and stability in acidic OER.The electron-withdrawing property of Mo enriches the electrophilic surface oxygen species,which promotes acidic OER to proceed via the adsorbate evolution pathway.As a result,we achieve a 189 mV overpotential at 10 mA·cm^(-2) and a Tafel slope of 48.8 mV·dec^(-1).Our catalyst demonstrates a substantial 18-fold increase in intrinsic activity,as evaluated by turnover frequency,compared to commercially available RuO_(2) and IrO_(2) catalysts.Moreover,we report a stable OER operation at 10 mA·cm^(-2) for 100 h with a low degradation rate of 2.05 mV·h^(-1).展开更多
To improve the oxidation resistance of short carbon fiber(C_(sf))-reinforced mechanically alloyed SiBCN(MA-SiBCN)(C_(sf)/MA-SiBCN)composites,dense amorphous C_(sf)/SiBCN composites containing both MA-SiBCN and polymer...To improve the oxidation resistance of short carbon fiber(C_(sf))-reinforced mechanically alloyed SiBCN(MA-SiBCN)(C_(sf)/MA-SiBCN)composites,dense amorphous C_(sf)/SiBCN composites containing both MA-SiBCN and polymer-derived ceramics SiBCN(PDCs-SiBCN)were prepared by repeated polymer infiltration and pyrolysis(PIP)of layered C_(sf)/MA-SiBCN composites at 1100℃,and the oxidation behavior and damage mechanism of the as-prepared C_(sf)/SiBCN at 1300–1600℃ were compared and discussed with those of C_(sf)/MA-SiBCN.The C_(sf)/MA-SiBCN composites resist oxidation attack up to 1400℃ but fail at 1500℃ due to the collapse of the porous framework,while the PIP-densified C_(sf)/SiBCN composites are resistant to static air up to 1600℃.During oxidation,oxygen diffuses through preexisting pores and the pores left by oxidation of carbon fibers and pyrolytic carbon(PyC)to the interior of the matrix.Owing to the oxidative coupling effect of the MA-SiBCN and PDCs-SiBCN matrices,a relatively continuous and dense oxide layer is formed on the sample surface,and the interfacial region between the oxide layer and the matrix of the as-prepared composite contains an amorphous glassy structure mainly consisting of Si and O and an incompletely oxidized but partially crystallized matrix,which is primarily responsible for improving the oxidation resistance.展开更多
Understanding and controlling phase separation in nonequilibrium colloidal systems are of both fundamental and applied importance.In this article,we investigate the spatiotemporal control of phase separation in chemic...Understanding and controlling phase separation in nonequilibrium colloidal systems are of both fundamental and applied importance.In this article,we investigate the spatiotemporal control of phase separation in chemically active immotile colloids.We show that a population of silver colloids can spontaneously phase separate into dense clusters in hydrogen peroxide(H_(2)O_(2))due to phoretic attraction.The characteristic length of the formed pattern was quantified and monitored over time,revealing a growth and coarsening phase with different growth kinetics.By tuning the trigger frequency of light,the lengths and growth kinetics of the clusters formed by silver colloids in H_(2)O_(2)can be controlled.In addition,structured light was used to precisely control the shape,size,and contour of the phase-separated patterns.This study provides insight into the microscopic details of the phase separation of chemically active colloids induced by phoretic attraction,and presents a generic strategy for controlling the spatiotemporal evolution of the resulting mesoscopic patterns.展开更多
Silver(Ag)paste is widely used in semiconductor metallization,especially in silicon solar cells.Ag powder is the material with the highest proportion in Ag paste.The morphology and structure of Ag powder are crucial w...Silver(Ag)paste is widely used in semiconductor metallization,especially in silicon solar cells.Ag powder is the material with the highest proportion in Ag paste.The morphology and structure of Ag powder are crucial which determine its characteristics,especially for the sintering activity.In this work,a simple method was developed to synthesize a type of microcrystalline spherical Ag particles(SP-A)with internal pores and the structural changes and sintering behavior were thoroughly studied by combining ultra-small-angle X-ray scattering(USAXS),small-angle X-ray scattering(SAXS),in-situ heating X-ray diffraction(XRD),focused ion beam(FIB),and thermal analysis measurement.Due to the unique internal pores,the grain size of SP-A is smaller,and the coefficient of thermal expansion(CTE)is higher than that of traditional solid Ag particles.As a result,the sintering activity of SP-A is excellent,which can form a denser sintered body and form silver nanoparticles at the Ag–Si interface to improve silver silicon contact.Polycrystalline silicon solar cell built with SP-A obtained a low series resistance(Rs)and a high photoelectric conversion efficiency(PCE)of 19.26%.These fill a gap in Ag particle structure research,which is significant for the development of high-performance electronic Ag particles and efficient semiconductor devices.展开更多
The coupling effects of ultrasonic excitation and high-strain-rate deformation are the core factors for weld formation during ultrasonic welding.However,interfacial deformation behavior still shrouds in uncer-tainty b...The coupling effects of ultrasonic excitation and high-strain-rate deformation are the core factors for weld formation during ultrasonic welding.However,interfacial deformation behavior still shrouds in uncer-tainty because of the contradictory features between mutual dislocation retardation caused by severely frictional deformation and ultrasonic-accelerated dislocation motion.[101]and[111]-oriented Cu single crystals which tended to form geometrically necessary boundaries(GNBs)were selected as the welding substrates to trace the uniquely acoustoplastic effects in the interfacial region under the ultrasonically excited high-strain-rate deformation.It was indicated that for a low energy input,micro-welds localized at the specific interface region,and equiaxed dislocation cells substituting for GNBs dominated in the ini-tial single crystal rotation region.As the welding energy increased,continuous shear deformation drove the dynamic recrystallization region covered by equiaxed grains to spread progressively.Limited discrete dislocations inside the recrystallized grains and nascent dislocation cells at the grain boundaries were ob-served in[101]and[111]joints simultaneously,suggesting that the ultrasonic excitation promoted motion of intragranular dislocation and pile-up along the sub-grain boundaries.The interfacial morphology be-fore and after expansion of recrystallization region all exhibited the weakening of orientation constraint on dislocation motion,which was also confirmed by the similar micro-hardness in joint interface.The first-principle calculation and applied strain-rate analysis further revealed that ultrasonic excitation en-hanced dislocation slipping,and enabled dislocation motion to accommodate severe plastic deformation at a high-strain-rate.展开更多
Deep Learning(DL)is a subfield of machine learning that significantly impacts extracting new knowledge.By using DL,the extraction of advanced data representations and knowledge can be made possible.Highly effective DL...Deep Learning(DL)is a subfield of machine learning that significantly impacts extracting new knowledge.By using DL,the extraction of advanced data representations and knowledge can be made possible.Highly effective DL techniques help to find more hidden knowledge.Deep learning has a promising future due to its great performance and accuracy.We need to understand the fundamentals and the state‐of‐the‐art of DL to leverage it effectively.A survey on DL ways,advantages,drawbacks,architectures,and methods to have a straightforward and clear understanding of it from different views is explained in the paper.Moreover,the existing related methods are compared with each other,and the application of DL is described in some applications,such as medical image analysis,handwriting recognition,and so on.展开更多
Transition metal carbide/nitride cores within MXenes make them considerably useful for ultra-high-temperature reinforcement.However,extensive research on Ti_(3)C_(2)T_(x) MXene has revealed its tendency to undergo a p...Transition metal carbide/nitride cores within MXenes make them considerably useful for ultra-high-temperature reinforcement.However,extensive research on Ti_(3)C_(2)T_(x) MXene has revealed its tendency to undergo a phase transition to TiCy at temperatures above 800℃due to high activity of a superficial Ti atomic layer.Herein,spark plasma sintering of Ti_(3)C_(2)T_(x) and TiC is performed to prevent the Ti_(3)C_(2)T_(x) phase transition at temperatures up to 1900℃through the fabrication of composites at a pressure of 50 MPa.Using a focused ion beam scanning electron microscope to separate layered substances in the composites and examining selected area diffraction spots in a transmission electron microscope enabled identification of non-phase-transitioned MXene.First-principles calculations based on density functional theory indicated the formation of strong chemical bonding interfaces between Ti_(3)C_(2)T_(x) and TiC,which imposed a stability constraint on the Ti atomic layer at the Ti_(3)C_(2)T_(x) surface.Mechanical performance tests,such as three-point bending and fracture toughness analysis,demonstrated that the addition of Ti_(3)C_(2)T_(x) can effectively improve the cross-scale strengthening and toughening of the TiC matrix,providing a new path for designing and developing two-dimensional(2D)carbides cross-scale-enhanced three-dimensional(3D)carbides with the same elements relying on a wide variety of MXenes.展开更多
Biomass carbon and small redox biomolecules are attractive materials for green,sustainable energy storage devices owing to their environmentally friendly,low-cost,scalable,and novel sources.However,most devices manufa...Biomass carbon and small redox biomolecules are attractive materials for green,sustainable energy storage devices owing to their environmentally friendly,low-cost,scalable,and novel sources.However,most devices manufactured using these materials have low specific capacitance,poor cycle stability,short lifetime,complexity,and low precision of device fabrication.Herein,we report the directed self-assembly of mononuclear anthraquinone(MAQ)derivatives and porous lignin-based graphene oxide(PLGO)into a renewable colloidal gel through noncovalent interactions.These self-assembled gel electrode materials exhibited high capacitance(484.8 F g^(−1) at a current density of 1 A g^(−1))and could be further printed as flexible micro-supercapacitors(FMSCs)with arbitrary patterns and a relatively high resolution on specific substrates.The FMSCs exhibited excellent areal capacitance(43.6 mF cm^(−2)),energy and power densities(6.1μWh cm^(−2) and 50μW cm^(−2),respectively),and cycle stability(>10,000 cycles).Furthermore,the printed FMSCs and integrated FMSC arrays exhibited remarkable flexibility while maintaining a stable capacitance.The proposed approach can be applied to other quinone biomolecules and biomass-based carbon materials.This study provides a basis for fabricating green and sustainable energy storage device architectures with high capacitance,long-term cycling,high scalability,and high precision.展开更多
Gallium-based liquid metals have attracted significant interest in the biomedical field due to their unique properties such as low viscosity,good fluidity,high thermal/electrical conductivity,and good biocompatibility...Gallium-based liquid metals have attracted significant interest in the biomedical field due to their unique properties such as low viscosity,good fluidity,high thermal/electrical conductivity,and good biocompatibility.Meanwhile,photothermal therapy has made great development in the field of antitumor with its advantages of low adverse effects,high specificity,and repeatable treatment.The photothermal capability possessed by gallium-based liquid metals makes them show unparalleled advantages in photothermal therapy.Liquid metal-based photothermal therapy has progressed in recent years and can perform a vital role in accurate and noninvasive antitumor therapy.Herein,a review of the major preparation methods of liquid metal micro/nanoparticles,the mechanism of liquid metal photothermal conversion,and discussions on the factors affecting the photothermal properties of liquid metals are presented.The biological applications of liquid metal photothermal therapy in synergy with other therapies are discussed,as well as the current challenges and opportunities for the clinical translation of liquid metals in biomedical applications.展开更多
Current gradient-index(GRIN)lens based proximal-driven intracoronary optical coherence tomography(ICOCT)probes consist of a spacer and a GRIN lens with large gradient constant.This design provides great flexibility to...Current gradient-index(GRIN)lens based proximal-driven intracoronary optical coherence tomography(ICOCT)probes consist of a spacer and a GRIN lens with large gradient constant.This design provides great flexibility to control beam profiles,but the spacer length should be well controlled to obtain desired beam profiles and thus it sets an obstacle in mass catheter fabrication.Besides,although GRIN lens with large gradient constant can provide tight focus spot,it has short depth of focus and fast-expanded beam which leads to poor lateral resolution for deep tissue.In this paper,a type of spacer-removed probe is demonstrated with a small gradient constant GRIN lens.This design simplifies the fabrica-tion process and is suitable for mass production.The output beam of the catheter is a narrow nearly collimated light beam,referred to as pencil beam here.The full width at half maximum beam size varies from 35.1μm to 75.3μm in air over 3-mm range.Probe design principles are elaborated with probe/catheter fabrication and performance test.The in vivo imaging of the catheter was verified by a clinical ICOCT system.Those results prove that this novel pencil-beam scanning catheter is potentially a good choice for ICOCT systems.展开更多
To investigate the real-time mean orbital elements(MOEs)estimation problem under the influence of state jumping caused by non-fatal spacecraft collision or protective orbit trans-fer,a modified augmented square-root u...To investigate the real-time mean orbital elements(MOEs)estimation problem under the influence of state jumping caused by non-fatal spacecraft collision or protective orbit trans-fer,a modified augmented square-root unscented Kalman filter(MASUKF)is proposed.The MASUKF is composed of sigma points calculation,time update,modified state jumping detec-tion,and measurement update.Compared with the filters used in the existing literature on MOEs estimation,it has three main characteristics.Firstly,the state vector is augmented from six to nine by the added thrust acceleration terms,which makes the fil-ter additionally give the state-jumping-thrust-acceleration esti-mation.Secondly,the normalized innovation is used for state jumping detection to set detection threshold concisely and make the filter detect various state jumping with low latency.Thirdly,when sate jumping is detected,the covariance matrix inflation will be done,and then an extra time update process will be con-ducted at this time instance before measurement update.In this way,the relatively large estimation error at the detection moment can significantly decrease.Finally,typical simulations are per-formed to illustrated the effectiveness of the method.展开更多
基金supported by the Natural Science Foundation of China(Grant No.51679060)。
文摘Predicting the performance of a tunneling boring machine is vitally important to avoid any possible accidents during tunneling boring.The prediction is not straightforward due to the uncertain geological conditions and the complex rock-machine interactions.Based on the big data obtained from the 72.1 km long tunnel in the Yin-Song Diversion Project in China,this study developed a machine learning model to predict the TBM performance in a real-time manner.The total thrust and the cutterhead torque during a stable period in a boring cycle was predicted in advance by using the machine-returned parameters in the rising period.A long short-term memory model was developed and its accuracy was evaluated.The results show that the variation in the total thrust and cutterhead torque with various geological conditions can be well reflected by the proposed model.This real-time predication shows superior performance than the classical theoretical model in which only a single value can be obtained based on the single measurement of the rock properties.To improve the accuracy of the model a filtering process was proposed.Results indicate that filtering the unnecessary parameters can enhance both the accuracy and the computational efficiency.Finally,the data deficiency was discussed by assuming a parameter was missing.It is found that the missing of a key parameter can significantly reduce the accuracy of the model,while the supplement of a parameter that highly-correlated with the missing one can improve the prediction.
基金supported by the Research Grants Council of the Hong Kong SAR Government(Nos.16205719,AoE/E-603/18 and 16206217)。
文摘Landslide identification is critical for risk assessment and mitigation.This paper proposes a novel machinelearning and deep-learning method to identify natural-terrain landslides using integrated geodatabases.First,landslide-related data are compiled,including topographic data,geological data and rainfall-related data.Then,three integrated geodatabases are established;namely,Recent Landslide Database(Rec LD),Relict Landslide Database(Rel LD)and Joint Landslide Database(JLD).After that,five machine learning and deep learning algorithms,including logistic regression(LR),support vector machine(SVM),random forest(RF),boosting methods and convolutional neural network(CNN),are utilized and evaluated on each database.A case study in Lantau,Hong Kong,is conducted to demonstrate the application of the proposed method.From the results of the case study,CNN achieves an identification accuracy of 92.5%on Rec LD,and outperforms other algorithms due to its strengths in feature extraction and multi dimensional data processing.Boosting methods come second in terms of accuracy,followed by RF,LR and SVM.By using machine learning and deep learning techniques,the proposed landslide identification method shows outstanding robustness and great potential in tackling the landslide identification problem.
基金the National Key R&D Program of China(2021YFA1401200)Beijing Outstanding Young Scientist Program(BJJWZYJH01201910007022)+2 种基金National Natural Science Foundation of China(No.U21A20140,No.92050117)Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park(No.Z211100004821009)X.Li acknowledges the support from Beijing Institute of Technology Research Fund Program for Young Scholars(XSQD-201904005).
文摘Color metasurface holograms are powerful and versatile platforms for modulating the amplitude,phase,polarization,and other properties of light at multiple operating wavelengths.However,the current color metasurface holography can only realize static manipulation.In this study,we propose and demonstrate a multiplexing metasurface technique combined with multiwavelength code-division multiplexing(CDM)to realize dynamic manipulation.Multicolor code references are utilized to record information within a single metasurface and increase the information capacity and security for anticracks.A total of 48 monochrome images consisting of pure color characters and multilevel color video frames were reconstructed in dual polarization channels of the birefringent metasurface to exhibit high information density,and a video was displayed via sequential illumination of the corresponding code patterns to verify the ability of dynamic manipulation.Our approach demonstrates significant application potential in optical data storage,optical encryption,multiwavelengthversatile diffractive optical elements,and stimulated emission depletion microscopy.
基金Project supported by the Research Council of Norwaythe National Natural Science Foundation of China(No.51979067)。
文摘Landslides represent major threats to life and property in many areas of the world,such as the landslides in the Three Gorges Dam area in China's Mainland.To better prepare for landslides in this area,we explored how several machine learning algorithms(long short term memory(LSTM),random forest(RF),and gated recurrent unit(GRU))might predict ground displacements under three types of landslides,each with distinct step-wise displacement characteristics.Landslide displacements are described with trend and periodic analyses and the predictions with each algorithm,validated with observations from the Three Gorges Dam reservoir over a one-year period.Results demonstrated that deep machine learning algorithms can be valuable tools for predicting landslide displacements,with the LSTM and GRU algorithms providing the most encouraging results.We recommend using these algorithms to predict landslide displacement of step-wise type landslides in the Three Gorges Dam area.Predictive models with similar reliability should gradually become a component when implementing early warning systems to reduce landslide risk.
基金supported by the National Natural Science Foundation of China (51672156)Local Innovative Research Teams Project of Guangdong Pearl River Talents Program (No. 2017BT01N111)+2 种基金Guangdong Province Technical Plan Project (2017B010119001)Shenzhen Technical Plan Project (JCYJ20170817161221958 and JCYJ20170412170706047)Shenzhen Graphene Manufacturing Innovation Center (201901161513)。
文摘Aqueous Zinc-ion batteries(ZIB) are attracting immense attention because of their merits of excellent safety and quite cheap properties compared with lithium-ion batteries(LIB).Manganese oxide is one of the most important cathode materials of ZIB.In this paper,α-Mn2O3 used as cathode of ZIB is synthesized via Metal-Organic Framework(MOF)-derived method,which delivers a high specific capacity of225 mAh g^(-1) at 0.05 A g^(-1) and 92.7 mAh g^(-1) after 1700 cycles at 2 A g^(-1).The charge storage mechanism of α-Mn2O3 cathode is found to greatly depend on the discharge current density.At lower current density discharging,the H+ and Zn2+ are successively intercalated into the α-Mn2O3 before and after the "turning point" of discharge voltage and their discharging products present obviously different morphologies changing from flower-like to large plate-like products.At a higher current density,the low-voltage plateau after the turning point disappears due to the decrease of amount of Zn2+ intercalation and the H+intercalation is dominated in α-Mn2 O3.This study provides significant understanding for future design and research of high-performance Mn-based cathodes of ZIB.
基金National Key Research and Development Program of China(2018YFB1801004)Ministry of Science and Technology of the People’s Republic of China(2018YFB1801003)+3 种基金National Natural Science Foundation of China(61675128,61875049,61875124,61935011,61975242)Guangzhou Science and Technology Program key projects(201904020048)Pearl River S&T Nova Program of Guangzhou(2017BT01X121)Science and Technology Planning Project of Guangdong Province(2019A1515010774)。
文摘In this work,on-chip chalcogenide glass photonic integrations with several fundamental photonic building blocks are designed and fabricated based on the As2 S3 platform for improved 2μm optical interconnection,achieving a broadened wavelength bandwidth and improved fabrication tolerance.A 600 nm thick As2 S3 strip waveguide has low propagation loss of 1.447 dB/cm at 2μm.Broadband vertical coupling is realized by a grating coupler with 4.3 dB coupling loss.A Bragg grating filter,power splitter,Mach–Zander interferometer,and mode converter for on-chip mode division multiplexing(MDM)are also reported at 2μm with reliable performances.Finally,a record high MDM optical interconnection capacity of 3×80 Gbps at 2μm is experimentally demonstrated based on the proposed As2 S3 chip,drawing promising prospects for future photonic integration and high-speed interconnection at the 2μm waveband.
基金supported by the Shenzhen Science and Tech-nology Program(KQTD20170809110344233)Shenzhen Bay Laboratory(SZBL201906281005)Shenzhen Science and Technology Program(Grant No.KQTD2016112814303055)。
文摘Real-time wireless respiratory monitoring and biomarker analysis provide an attractive vision for noninvasive telemedicine such as the timely prevention of respiratory arrest or for early diagnoses of chronic diseases.Lightweight,wearable respiratory sensors are in high demand as they meet the requirement of portability in digital healthcare management.Meanwhile,high-performance sensing material plays a crucial role for the precise sensing of specific markers in exhaled air,which represents a complex and rather humid environment.Here,we present a liquid metal-based flexible electrode coupled with SnS_(2)nanomaterials as a wearable gas-sensing device,with added Bluetooth capabilities for remote respiratory monitoring and diagnoses.The flexible epidermal device exhibits superior skin compatibility and high responsiveness(1092%/ppm),ultralow detection limits(1.32 ppb),and a good selectivity of NO gas at ppb-level concentrations.Taking advantage of the fast recovery kinetics of SnS_(2)responding to H_(2)O molecules,it is possible to accurately distinguish between different respiratory patterns based on the amount of water vapor in the exhaled air.Furthermore,based on the different redox types of H_(2)O and NO molecules,the electric signal is reversed once the exhaled NO concentration exceeds a certain threshold that may indicate the onset of conditions like asthma,thus providing an early warning system for potential lung diseases.Finally,by integrating the wearable device into a wireless cloud-based multichannel interface,we provide a proof-of-concept that our device could be used for the simultaneous remote monitoring of several patients with respiratory diseases,a crucial field in future digital healthcare management.
基金funded by the National Natural Science Foundation of China(No.51961165104)Project of Thousand Youth Talents(No.AUGA2160100917)+1 种基金University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province(No.UNPYSCT-2020050)Provincial Leading Talent Echelon Cultivation Project of Heilongjiang Institute of Technology(No.2020LJ04)。
文摘Biochar(BC)are widely used as highly efficient adsorbents to alleviate aromatics-based contaminants due to their ease of preparation,wide availability,and high sustainability.The surface properties of BCs usually vary greatly due to their complex chemical constituents and different preparation processes and are reflected in the values of parameters such as the specific surface area(SSA),pore volume/size,and surface functional groups(SFGs).The effects of SSA and pore volume/size on the adsorption of aromatics have been widely reported.However,the corresponding mechanisms of BC SFGs towards aromatics adsorption remains unclear as the compositions of the SFGs are usually complex and hard to determine.To address in this gap in the literature,this review introduces a new perspective on the adsorption mechanisms of aromatics.Through collecting previously-reported results,the parameters log P(logarithm of the Kow),polar surface area,and the positive/negative charges were carefully calculated using Chem Draw3D,which allowed the hydrophobicity/hydrophilicity properties,electron donor-acceptor interactions,Hbonding,and electrostatic interactions between SFGs and aromatics-based contaminates to be inferred intuitively.These predictions were consistent with the reported results and showed that tailor-made BCs can be designed according to the molecular weights,chemical structures,and polarities of the target aromatics.Overall,this review provides new insight into predicting the physicochemical properties of BCs through revealing the relationship between SFGs and adsorbates,which may provide useful guidance for the preparing of highly-efficient,functional BCs for the adsorption of aromatics.
基金supported financially by the National Natural Science Foundation of China(No.51802060)the Shenzhen Innovation Project(No.KQJSCX20170726104623185)the Shenzhen Peacock Group(No.KQTD20170809110344233).
文摘Surface-enhanced Raman spectroscopy(SERS),as a highly sensitive molecular analysis technique,can realize fast and non-destructive detection of the information of molecular bonds to identify the component of analytes by"fingerprint"identification.The preparation of SERS substrates plays an extremely important role in the development of SERS technology and the application of SERS detection.By integrating SERS enhancement substrates into microfluidic chips,researchers have developed the microfluidic SERS chips which expand the function of microfluidic chips and provide an efficient platform for on-site biochemical analysis equipped with the powerful sensing capability of SERS technique.In this paper,we will first briefly give a review of the current microfluidic SERS-active substrates preparation technology and present the perspective on the application prospects of microfluidic SERS-active substrates.And then the challenges in the preparation of microfluidic SERS-active substrates will be pointed out,as well as realistic issues of using this technology for biochemical application.
基金support from the National Natural Science Foundation of China(No.52103300)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515010572)+7 种基金the Shenzhen Science and Technology Program(Nos.JCYJ20210324132806017 and GXWD20220811163904001)the Innovation Material Research Center of Harbin Institute of Technology,Shenzhen for the instrumentation assistance.Y.H.W.acknowledges the funding support from the National Natural Science Foundation of China(No.22179088)the Natural Science Foundation of Jiangsu Province of China(No.BK20210699)the National Natural Science Fund for Excellent Young Scientists Fund Program(Overseas)the Program for Jiangsu Specially-Appointed Professors,the Program of Soochow Innovation and Entrepreneurship Leading Talents(No.ZXL2022450)the start-up supports of Soochow University,Suzhou Key Laboratory of Functional Nano&Soft Materials,the Collaborative Innovation Center of Suzhou Nano Science&Technology,the 111 Project,the Joint International Research Laboratory of Carbon-Based Functional Materials and Devices.J.Z.acknowledges the funding support from the State Key Laboratory of Urban Water Resources&Environment(Harbin Institute of Technology)(No.2022TS36)Computer time made available by the National Supercomputing Center of China in Shenzhen(Shenzhen Cloud Computing Center)is gratefully acknowledged.J.L.acknowledges the start-up funding support from Shanghai Jiao Tong University(No.WH220432516)This research used synchrotron resources of the Advanced Photon Source,an Office of Science User Facility operated for the US Department of Energy Office of Science by Argonne National Laboratory and was supported by the US Department of Energy under contract No.DE-AC02-06CH11357 and the Canadian Light Source and its funding partners.
文摘The polymer electrolyte membrane(PEM)electrolyzers are burdened with costly iridium(Ir)-based catalysts and high operation overpotentials for the oxygen evolution reaction(OER).The development of earth-abundant,highly active,and durable electrocatalysts to replace Ir is a critical step in reducing the cost of green hydrogen production.Here we develop a Ru5Mo4Ox binary oxide catalyst that exhibits high activity and stability in acidic OER.The electron-withdrawing property of Mo enriches the electrophilic surface oxygen species,which promotes acidic OER to proceed via the adsorbate evolution pathway.As a result,we achieve a 189 mV overpotential at 10 mA·cm^(-2) and a Tafel slope of 48.8 mV·dec^(-1).Our catalyst demonstrates a substantial 18-fold increase in intrinsic activity,as evaluated by turnover frequency,compared to commercially available RuO_(2) and IrO_(2) catalysts.Moreover,we report a stable OER operation at 10 mA·cm^(-2) for 100 h with a low degradation rate of 2.05 mV·h^(-1).
基金the National Natural Science Foundation of China(Nos.52372059,52172068,52232004,and 52002092)the Heilongjiang Natural Science Fund for Young Scholars(No.YQ2021E017)+3 种基金the Fundamental Research Funds for the Central Universities(No.2022FRFK060012)the Heilongjiang Touyan Team Program,and the Advanced Talents Scientific Research Foundation of Shenzhen:Yu Zhou.the Beijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology and Advanced Space Propulsion Laboratory of BICE(No.LabASP-2023-11)the Huiyan Action(No.1A423653)the Key Technologies R&D Program of CNBM(No.2023SJYL05).Ralf Riedel also gratefully acknowledges the financial support provided by the Research Training Group 2561“MatCom-ComMat:Materials Compounds from Composite Materials for Applications in Extreme Conditions”funded by the Deutsche Forschungsgemeinschaft(DFG),Bonn,Germany.
文摘To improve the oxidation resistance of short carbon fiber(C_(sf))-reinforced mechanically alloyed SiBCN(MA-SiBCN)(C_(sf)/MA-SiBCN)composites,dense amorphous C_(sf)/SiBCN composites containing both MA-SiBCN and polymer-derived ceramics SiBCN(PDCs-SiBCN)were prepared by repeated polymer infiltration and pyrolysis(PIP)of layered C_(sf)/MA-SiBCN composites at 1100℃,and the oxidation behavior and damage mechanism of the as-prepared C_(sf)/SiBCN at 1300–1600℃ were compared and discussed with those of C_(sf)/MA-SiBCN.The C_(sf)/MA-SiBCN composites resist oxidation attack up to 1400℃ but fail at 1500℃ due to the collapse of the porous framework,while the PIP-densified C_(sf)/SiBCN composites are resistant to static air up to 1600℃.During oxidation,oxygen diffuses through preexisting pores and the pores left by oxidation of carbon fibers and pyrolytic carbon(PyC)to the interior of the matrix.Owing to the oxidative coupling effect of the MA-SiBCN and PDCs-SiBCN matrices,a relatively continuous and dense oxide layer is formed on the sample surface,and the interfacial region between the oxide layer and the matrix of the as-prepared composite contains an amorphous glassy structure mainly consisting of Si and O and an incompletely oxidized but partially crystallized matrix,which is primarily responsible for improving the oxidation resistance.
基金supported by the Shenzhen Science and Technology Program(RCYX20210609103122038 and JCYJ20210324121408022)the National Natural Science Foundation of China(T2322006,T2325027,12274448,12225410 and 12074243)
文摘Understanding and controlling phase separation in nonequilibrium colloidal systems are of both fundamental and applied importance.In this article,we investigate the spatiotemporal control of phase separation in chemically active immotile colloids.We show that a population of silver colloids can spontaneously phase separate into dense clusters in hydrogen peroxide(H_(2)O_(2))due to phoretic attraction.The characteristic length of the formed pattern was quantified and monitored over time,revealing a growth and coarsening phase with different growth kinetics.By tuning the trigger frequency of light,the lengths and growth kinetics of the clusters formed by silver colloids in H_(2)O_(2)can be controlled.In addition,structured light was used to precisely control the shape,size,and contour of the phase-separated patterns.This study provides insight into the microscopic details of the phase separation of chemically active colloids induced by phoretic attraction,and presents a generic strategy for controlling the spatiotemporal evolution of the resulting mesoscopic patterns.
基金support of the Soft Science Research Project of Guangdong Province(No.2017B030301013)the Guangdong Innovative Team Program(No.2013N080)the Guangdong Province Major Talent Introducing Program(No.2021QN020687).
文摘Silver(Ag)paste is widely used in semiconductor metallization,especially in silicon solar cells.Ag powder is the material with the highest proportion in Ag paste.The morphology and structure of Ag powder are crucial which determine its characteristics,especially for the sintering activity.In this work,a simple method was developed to synthesize a type of microcrystalline spherical Ag particles(SP-A)with internal pores and the structural changes and sintering behavior were thoroughly studied by combining ultra-small-angle X-ray scattering(USAXS),small-angle X-ray scattering(SAXS),in-situ heating X-ray diffraction(XRD),focused ion beam(FIB),and thermal analysis measurement.Due to the unique internal pores,the grain size of SP-A is smaller,and the coefficient of thermal expansion(CTE)is higher than that of traditional solid Ag particles.As a result,the sintering activity of SP-A is excellent,which can form a denser sintered body and form silver nanoparticles at the Ag–Si interface to improve silver silicon contact.Polycrystalline silicon solar cell built with SP-A obtained a low series resistance(Rs)and a high photoelectric conversion efficiency(PCE)of 19.26%.These fill a gap in Ag particle structure research,which is significant for the development of high-performance electronic Ag particles and efficient semiconductor devices.
基金supported by the National Nat-ural Science Foundation of China(No.52175310)A part of the work was also supported by the National Science and Technology Major Project(No.2017-VI-0009-0080)+1 种基金the Guang-dong Province Key Research and Development Program(No.2019B010935001)and the Shenzhen Science and Technology Plan(No.GXWD20201230155427003-20200821172456002).
文摘The coupling effects of ultrasonic excitation and high-strain-rate deformation are the core factors for weld formation during ultrasonic welding.However,interfacial deformation behavior still shrouds in uncer-tainty because of the contradictory features between mutual dislocation retardation caused by severely frictional deformation and ultrasonic-accelerated dislocation motion.[101]and[111]-oriented Cu single crystals which tended to form geometrically necessary boundaries(GNBs)were selected as the welding substrates to trace the uniquely acoustoplastic effects in the interfacial region under the ultrasonically excited high-strain-rate deformation.It was indicated that for a low energy input,micro-welds localized at the specific interface region,and equiaxed dislocation cells substituting for GNBs dominated in the ini-tial single crystal rotation region.As the welding energy increased,continuous shear deformation drove the dynamic recrystallization region covered by equiaxed grains to spread progressively.Limited discrete dislocations inside the recrystallized grains and nascent dislocation cells at the grain boundaries were ob-served in[101]and[111]joints simultaneously,suggesting that the ultrasonic excitation promoted motion of intragranular dislocation and pile-up along the sub-grain boundaries.The interfacial morphology be-fore and after expansion of recrystallization region all exhibited the weakening of orientation constraint on dislocation motion,which was also confirmed by the similar micro-hardness in joint interface.The first-principle calculation and applied strain-rate analysis further revealed that ultrasonic excitation en-hanced dislocation slipping,and enabled dislocation motion to accommodate severe plastic deformation at a high-strain-rate.
文摘Deep Learning(DL)is a subfield of machine learning that significantly impacts extracting new knowledge.By using DL,the extraction of advanced data representations and knowledge can be made possible.Highly effective DL techniques help to find more hidden knowledge.Deep learning has a promising future due to its great performance and accuracy.We need to understand the fundamentals and the state‐of‐the‐art of DL to leverage it effectively.A survey on DL ways,advantages,drawbacks,architectures,and methods to have a straightforward and clear understanding of it from different views is explained in the paper.Moreover,the existing related methods are compared with each other,and the application of DL is described in some applications,such as medical image analysis,handwriting recognition,and so on.
基金the financial support from the National Natural Science Foundation of China(Grant Nos.11872171,91016014,and 51872062)Fundamental Research Funds for the Central Universities(Grant No.B200202117)。
文摘Transition metal carbide/nitride cores within MXenes make them considerably useful for ultra-high-temperature reinforcement.However,extensive research on Ti_(3)C_(2)T_(x) MXene has revealed its tendency to undergo a phase transition to TiCy at temperatures above 800℃due to high activity of a superficial Ti atomic layer.Herein,spark plasma sintering of Ti_(3)C_(2)T_(x) and TiC is performed to prevent the Ti_(3)C_(2)T_(x) phase transition at temperatures up to 1900℃through the fabrication of composites at a pressure of 50 MPa.Using a focused ion beam scanning electron microscope to separate layered substances in the composites and examining selected area diffraction spots in a transmission electron microscope enabled identification of non-phase-transitioned MXene.First-principles calculations based on density functional theory indicated the formation of strong chemical bonding interfaces between Ti_(3)C_(2)T_(x) and TiC,which imposed a stability constraint on the Ti atomic layer at the Ti_(3)C_(2)T_(x) surface.Mechanical performance tests,such as three-point bending and fracture toughness analysis,demonstrated that the addition of Ti_(3)C_(2)T_(x) can effectively improve the cross-scale strengthening and toughening of the TiC matrix,providing a new path for designing and developing two-dimensional(2D)carbides cross-scale-enhanced three-dimensional(3D)carbides with the same elements relying on a wide variety of MXenes.
基金supported by the National Natural Science Foundation of China(Grant Nos.21905069 and U21A20307)the Shenzhen Science and Technology Innovation Committee(Grant Nos.ZDSYS20190902093220279,KQTD20170809110344233,GXWD20201230155427003-20200821181245001,GXWD20201230155427003-20200821181809001,and ZX20200151)+1 种基金the Department of Science and Technology of Guangdong Province(Grant No.2020A1515110879)University Stable Support Foundation of Shenzhen(Grant No.GXWD20201230155427003-20200821181809001).
文摘Biomass carbon and small redox biomolecules are attractive materials for green,sustainable energy storage devices owing to their environmentally friendly,low-cost,scalable,and novel sources.However,most devices manufactured using these materials have low specific capacitance,poor cycle stability,short lifetime,complexity,and low precision of device fabrication.Herein,we report the directed self-assembly of mononuclear anthraquinone(MAQ)derivatives and porous lignin-based graphene oxide(PLGO)into a renewable colloidal gel through noncovalent interactions.These self-assembled gel electrode materials exhibited high capacitance(484.8 F g^(−1) at a current density of 1 A g^(−1))and could be further printed as flexible micro-supercapacitors(FMSCs)with arbitrary patterns and a relatively high resolution on specific substrates.The FMSCs exhibited excellent areal capacitance(43.6 mF cm^(−2)),energy and power densities(6.1μWh cm^(−2) and 50μW cm^(−2),respectively),and cycle stability(>10,000 cycles).Furthermore,the printed FMSCs and integrated FMSC arrays exhibited remarkable flexibility while maintaining a stable capacitance.The proposed approach can be applied to other quinone biomolecules and biomass-based carbon materials.This study provides a basis for fabricating green and sustainable energy storage device architectures with high capacitance,long-term cycling,high scalability,and high precision.
基金the financial support from the National Natural Science Foundation of China(Nos.52072095 and 92163109)the Shenzhen Science and Technology Program(Nos.JCYJ20200109113408066,KQTD20170809110344233,and RCBS20210609103646022)+2 种基金Shenzhen Bay Laboratory(No.SZBL2019062801005)the Fundamental Research Funds for the Central Universities(No.HIT.OCEF.2021032)the GuangDong Basic and Applied Basic Research Foundation(No.2021A1515110272).
文摘Gallium-based liquid metals have attracted significant interest in the biomedical field due to their unique properties such as low viscosity,good fluidity,high thermal/electrical conductivity,and good biocompatibility.Meanwhile,photothermal therapy has made great development in the field of antitumor with its advantages of low adverse effects,high specificity,and repeatable treatment.The photothermal capability possessed by gallium-based liquid metals makes them show unparalleled advantages in photothermal therapy.Liquid metal-based photothermal therapy has progressed in recent years and can perform a vital role in accurate and noninvasive antitumor therapy.Herein,a review of the major preparation methods of liquid metal micro/nanoparticles,the mechanism of liquid metal photothermal conversion,and discussions on the factors affecting the photothermal properties of liquid metals are presented.The biological applications of liquid metal photothermal therapy in synergy with other therapies are discussed,as well as the current challenges and opportunities for the clinical translation of liquid metals in biomedical applications.
基金financial supports from the National Natural Science Foundation of China(Grant No.81927805)Shenzhen Municipal Science and Technology Plan Project,China(Grant No.JCYJ20160427183803458)。
文摘Current gradient-index(GRIN)lens based proximal-driven intracoronary optical coherence tomography(ICOCT)probes consist of a spacer and a GRIN lens with large gradient constant.This design provides great flexibility to control beam profiles,but the spacer length should be well controlled to obtain desired beam profiles and thus it sets an obstacle in mass catheter fabrication.Besides,although GRIN lens with large gradient constant can provide tight focus spot,it has short depth of focus and fast-expanded beam which leads to poor lateral resolution for deep tissue.In this paper,a type of spacer-removed probe is demonstrated with a small gradient constant GRIN lens.This design simplifies the fabrica-tion process and is suitable for mass production.The output beam of the catheter is a narrow nearly collimated light beam,referred to as pencil beam here.The full width at half maximum beam size varies from 35.1μm to 75.3μm in air over 3-mm range.Probe design principles are elaborated with probe/catheter fabrication and performance test.The in vivo imaging of the catheter was verified by a clinical ICOCT system.Those results prove that this novel pencil-beam scanning catheter is potentially a good choice for ICOCT systems.
基金This work was supported by National Natural Science Foundation of China(12372045)Shanghai Aerospace Science and Technology Program(SAST2021-030).
文摘To investigate the real-time mean orbital elements(MOEs)estimation problem under the influence of state jumping caused by non-fatal spacecraft collision or protective orbit trans-fer,a modified augmented square-root unscented Kalman filter(MASUKF)is proposed.The MASUKF is composed of sigma points calculation,time update,modified state jumping detec-tion,and measurement update.Compared with the filters used in the existing literature on MOEs estimation,it has three main characteristics.Firstly,the state vector is augmented from six to nine by the added thrust acceleration terms,which makes the fil-ter additionally give the state-jumping-thrust-acceleration esti-mation.Secondly,the normalized innovation is used for state jumping detection to set detection threshold concisely and make the filter detect various state jumping with low latency.Thirdly,when sate jumping is detected,the covariance matrix inflation will be done,and then an extra time update process will be con-ducted at this time instance before measurement update.In this way,the relatively large estimation error at the detection moment can significantly decrease.Finally,typical simulations are per-formed to illustrated the effectiveness of the method.
