Predicting the constitutive response of granular soils is a fundamental goal in geomechanics.This paper presents a machine learning(ML)framework for the prediction of the stress-strain behaviour and shearinduced conta...Predicting the constitutive response of granular soils is a fundamental goal in geomechanics.This paper presents a machine learning(ML)framework for the prediction of the stress-strain behaviour and shearinduced contact fabric evolution of an idealised granular material subject to triaxial shearing.The MLbased framework is comprised of a set of mini-triaxial tests which provide a benchmark for the setup and validation of the discrete element method(DEM)model of the granular materials,a parametric DEM simulation programme of virtual triaxial tests which provides datasets of micro-and macro-mechanical information,as well as a multi-layer perceptron(MLP)neural network which is trained and tested using the DEM-based datasets.The ML model only requires the initial void ratio of the granular sample as the input for predicting its constitutive response.The excellent agreement between the ML model prediction and experimental test and DEM simulation results indicates that the MLebased modelling approach is capable of capturing accurately the effects of initial void ratio on the constitutive behaviour of idealised granular materials,bypassing the need to incorporate the complex micromechanics underlying the macroscopic mechanical behaviour of granular materials.Lastly,a detailed comparison between the used MLP model and long short-term memory(LSTM)model was made from the perspective of technical algorithm,prediction accuracy,and computational efficiency.展开更多
Discrete element method(DEM)has been widely utilised to model the mechanical behaviours of granular materials.However,with simplified particle morphology or rheology-based rolling resistance models,DEM failed to descr...Discrete element method(DEM)has been widely utilised to model the mechanical behaviours of granular materials.However,with simplified particle morphology or rheology-based rolling resistance models,DEM failed to describe some responses,such as the particle kinematics at the grain-scale and the principal stress ratio against axial strain at the macro-scale.This paper adopts a computed tomography(CT)-based DEM technique,including particle morphology data acquisition from micro-CT(mCT),spherical harmonic-based principal component analysis(SH-PCA)-based particle morphology reconstruction and DEM simulations,to investigate the capability of DEM with realistic particle morphology for modelling granular soils’micro-macro mechanical responses with a consideration of the initial packing state,the morphological gene mutation degree,and the confining stress condition.It is found that DEM with realistic particle morphology can reasonably reproduce granular materials’micro-macro mechanical behaviours,including the deviatoric stressevolumetric straineaxial strain response,critical state behaviour,particle kinematics,and shear band evolution.Meanwhile,the role of multiscale particle morphology in granular soils depends on the initial packing state and the confining stress condition.For the same granular soils,rougher particle surfaces with a denser initial packing state and a higher confining stress condition result in a higher degree of shear strain localisation.展开更多
Porous active core-shell carbon material with excellent synergistic effect has been regarded as a prospective material for supercapacitors.Herein,we report an integrated method for the facile synthesis of carbide-deri...Porous active core-shell carbon material with excellent synergistic effect has been regarded as a prospective material for supercapacitors.Herein,we report an integrated method for the facile synthesis of carbide-derived carbon(CDC)encapsulated with porous N-doped carbon(CDC@NC)towards highperformance supercapacitors.Polydopamine(PDA)as nitrogen and carbon sources was simply coated on SiC nanospheres to form SiC@PDA,which was then directly transformed into CDC@NC via a onestep molten salt electro-etching/in-situ doping process.The synthesized CDC@NC with hierarchically porous structure has a high specific surface area of 1191 m^(2) g^(-1).The CDC core and NC shell are typical amorphous carbon and more ordered N-doped carbon,respectively.Benefitting from its unique dual porous structures,the CDC@NC demonstrates high specific capacitances of 255 and 193 F g^(-1) at 0.5 and20 A g^(-1),respectively.The reaction mechanism of the electro-etching/in-situ doping process has also been investigated through experimental characterizations and theoretical density functional theory calculations.It is suggested that the molten salt electro-etching/in-situ doping strategy is promising for the synthesis of active core-shell porous carbon materials with synergistic properties for supercapacitors without the need for additional doping/activation processes.展开更多
Developing flexible sensors with high working performance holds intense interest for diverse applications in leveraging the Internet-of-things(IoT)infrastructures.For flexible piezoresistive sensors,traditionally most...Developing flexible sensors with high working performance holds intense interest for diverse applications in leveraging the Internet-of-things(IoT)infrastructures.For flexible piezoresistive sensors,traditionally most efforts are focused on tailoring the sensing materials to enhance the contact resistance variation for improving the sensitivity and working range,and it,however,remains challenging to simultaneously achieve flexible sensor with a linear working range over a high-pressure region(>100 kPa)and keep a reliable sensitivity.Herein,we devised a laserengraved silver-coated fabric as"soft"sensor electrode material to markedly advance the flexible sensor's linear working range to a level of 800 kPa with a high sensitivity of 6.4 kPa^-1 yet a fast response time of only 4 ms as well as long-time durability,which was rarely reported before.The integrated sensor successfully routed the wireless signal of pulse rate to the portable smartphone,further demonstrating its potential as a reliable electronic.Along with the rationally building the electrode instead of merely focusing on sensing materials capable of significantly improving the sensor's performance,we expect that this design concept and sensor system could potentially pave the way for developing more advanced wearable electronics in the future.展开更多
In this paper,the X-ray micro-computed tomography(X-rayμCT),spherical harmonical-based principal component analysis(SH-PCA),and discrete element method(DEM)were incorporated to generate virtual samples with morpholog...In this paper,the X-ray micro-computed tomography(X-rayμCT),spherical harmonical-based principal component analysis(SH-PCA),and discrete element method(DEM)were incorporated to generate virtual samples with morphological gene mutation at different length scales.All samples were subjected to axial compression and constant confining stress.The effects of multiscale particle morphology on the stress-strain and energy storage/dissipation responses of granular soils were investigated.It is found that:(a)the effects of particle morphology on the initial stiffness,stress-strain,volumetric strain,and frictional energy dissipation behaviours are more pronounced for looser samples than for denser ones;(b)among different length scales,the particle morphology at the local roundness-level outperforms the one at the general form-level in dictating the macro-scale responses of granular soils;(c)the energy dissipation of a granular assemblage is a result of competition between particle morphology and initial void ratio.展开更多
Due to the enhanced ambient structural stability and excellent optoelectronic properties, all-inorganic metal halide perovskite nanowires have become one of the most attractive candidates for flexible electronics, pho...Due to the enhanced ambient structural stability and excellent optoelectronic properties, all-inorganic metal halide perovskite nanowires have become one of the most attractive candidates for flexible electronics, photovoltaics and optoelectronics. Their elastic property and mechanical robustness become the key factors for device applications under realistic service conditions with various mechanical loadings. Here, we demonstrate that high tensile elastic strain (∼ 4% to ∼ 5.1%) can be achieved in vapor-liquid-solid-grown single-crystalline CsPbBr_(3) nanowires through in situ scanning electron microscope (SEM) buckling experiments. Such high flexural elasticity can be attributed to the structural defect-scarce, smooth surface, single-crystallinity and nanomechanical size effect of CsPbBr_(3) nanowires. The mechanical reliability of CsPbBr_(3) nanowire-based flexible photodetectors was examined by cyclic bending tests, with no noticeable performance deterioration observed after 5,000 cycles. The above results suggest great application potential for using all-inorganic perovskite nanowires in flexible electronics and energy harvesting systems.展开更多
This study has investigated the effects of gold nanoparticles (Au NPs) on the proliferation, differentiation, and mineralization of a murine preosteoblast cell line MC3T3-E1 in vitro. The results show that Au NPs with...This study has investigated the effects of gold nanoparticles (Au NPs) on the proliferation, differentiation, and mineralization of a murine preosteoblast cell line MC3T3-E1 in vitro. The results show that Au NPs with diameters of both 20 and 40 nm promoted the proliferation, differentiation, and mineralization of MC3T3-E1 cells in a time- and dose-dependent manner at the concentra-tions of 1.5×10-5, 3.0×10-5, and 1.5×10-4 μmol/L. The reverse transcriptase polymerase chain reaction (RT-PCR) indicates that the expressions of runt-related transcription factor 2 (Runx2), bone morphogenetic protein 2 (BMP-2), alkaline phosphatase (ALP), and osteocalcin (OCN) genes increased after the 20 and 40 nm Au NP treatments, and the expression levels were higher than those of the NaF group. The above results suggest that Au NPs have the potential to promote the osteogenic differentiation and miner- alization of MC3T3-E1 cells and the particle size plays a significant role in the process. Runx2, BMP-2, ALP, and OCN genes may interact with each other, further stimulating the osteogenic differentiation of MC3T3-E1 cells.展开更多
3D printing-based supercapacitors have been extensively explored,yet the rigid rheological requirement for corresponding ink preparation significantly limits the manufacturing of true 3D architecture in achieving supe...3D printing-based supercapacitors have been extensively explored,yet the rigid rheological requirement for corresponding ink preparation significantly limits the manufacturing of true 3D architecture in achieving superior energy storage.We proposed the stereolithographic technique to fabricate the metallic composite lattices with octet-truss arrangement by using electroless plating and engineering the 3D hierarchically porous graphene onto the scaffolds to build the hierarchically cellular lattices in quasi-solid supercapacitor application.The supercapacitor device that is composed of composite lattices span several pore size orders from nm to mm holds promising behavior on the areal capacitance(57.75 mF cm-2),rate capability(70% retention,2-40 mA cm-2),and long lifespan(96% after 5000 cycles),as well as superior energy density of 0.008 mWh cm-2,which are comparable to the state-of-the-art carbon-based supercapacitor.By synergistically combining this facile stereolithographic 3D printing technology with the hierarchically porous graphene architecture,we provide a novel route of manufacturing energy storage device as well as new insight into building other high-performance functional electronics.展开更多
Diamond,as an ultra-wide bandgap semiconductor,has become a promising candidate for next-generation microelec-tronics and optoelectronics due to its numerous advantages over conventional semiconductors,including ultra...Diamond,as an ultra-wide bandgap semiconductor,has become a promising candidate for next-generation microelec-tronics and optoelectronics due to its numerous advantages over conventional semiconductors,including ultrahigh carrier mo-bility and thermal conductivity,low thermal expansion coefficient,and ultra-high breakdown voltage,etc.Despite these ex-traordinary properties,diamond also faces various challenges before being practically used in the semiconductor industry.This review begins with a brief summary of previous efforts to model and construct diamond-based high-voltage switching diodes,high-power/high-frequency field-effect transistors,MEMS/NEMS,and devices operating at high temperatures.Following that,we will discuss recent developments to address scalable diamond device applications,emphasizing the synthesis of large-area,high-quality CVD diamond films and difficulties in diamond doping.Lastly,we show potential solutions to modulate diamond’s electronic properties by the“elastic strain engineering”strategy,which sheds light on the future development of diamond-based electronics,photonics and quantum systems.展开更多
The development of a miniature triaxial apparatus is presented.In conjunction with an X-ray microtomography(termed as X-ray fiCT hereafter)facility and advanced image processing techniques,this apparatus can be used f...The development of a miniature triaxial apparatus is presented.In conjunction with an X-ray microtomography(termed as X-ray fiCT hereafter)facility and advanced image processing techniques,this apparatus can be used for in situ investigation of the micro-scale mechanical behavior of granular soils under shear.The apparatus allows for triaxial testing of a miniature dry sample with a size of 8 mm x 16 mm(diameter x height).In situ triaxial testing of a 0.4-0.8 mm Leighton Buzzard sand(LBS)under a constant confining pressure of 500 kPa is presented.The evolutions of local porosities(i.e.,the porosities of regions associated with individual particles),particle kinematics(i.e.,particle translation and particle rotation)of the sample during the shear are quantitatively studied using image processing and analysis techniques.Meanwhile,a novel method is presented to quantify the volumetric strain distribution of the sample based on the results of local porosities and particle tracking.It is found that the sample,with nearly homogenous initial local porosities,starts to exhibit obvious inhomogeneity of local porosities and localization of particle kinematics and volumetric strain around the peak of deviatoric stress.In the post-peak shear stage,large local porosities and volumetric dilation mainly occur in a localized band.The developed triaxial apparatus,in its combined use of X-ray|iCT imaging techniques,is a powerful tool to investigate the micro-scale mechanical behavior of granular soils.展开更多
In this study,discrete element method(DEM)simulations of a biaxial test were used to examine the effect of particle roundness on the mechanical behavior of sands at both the macro and micro scales.First,a stack of mic...In this study,discrete element method(DEM)simulations of a biaxial test were used to examine the effect of particle roundness on the mechanical behavior of sands at both the macro and micro scales.First,a stack of microcomputed tomography images were binarized,segmented,and labeled using advanced image processing and analysis techniques.Second,a spherical harmonic(SH)analysis,which involves a complete set of orthogonal functions,was implemented to rebuild the natural particle shape.Then,five templates of virtual particles were built in a DEM simulation,four of which were obtained from SH degrees of 3,8,12,and 15,and one template was an elementary sphere.A flexible membrane was numerically generated to allow the material to deform freely under a prescribed confining stress.Finally,the effect of particle roundness on the mechanical properties of granular materials was investigated and discussed.Two shear bands were found to intersect,forming an X shape in both the rotation and displacement fields.Moreover,a lower particle roundness results in higher deviatoric stress and stronger dilation in the volumetric change.A decrease in particle roundness leads to less rotation of particles despite a higher displacement value.In addition,a larger SH degree leads to smaller normalized contact forces of the particles.This implies that decreasing the roundness results in higher anisotropy of the contact forces.展开更多
Lysine acetylation is one of the most prevalent and important posttranslational modifications(PTMs) in proteins. The process can be recognized by bromodomains(BRDs), which are a class of proteininteraction modules inv...Lysine acetylation is one of the most prevalent and important posttranslational modifications(PTMs) in proteins. The process can be recognized by bromodomains(BRDs), which are a class of proteininteraction modules involved in chromatin remodeling and transcriptional activation. The development of BRD fluorescent probes will be useful for monitoring the activity of BRDs in living cells as well as aiding inhibitor development. Herein we designed a peptide-based probe based on the proximity-induced protein conjugation reaction. The peptide-based probe is capable of covalently and selectively reacting with the unique cysteine residue in the bromodomain through proximity effect. Our experimental data showed that the probe displayed noticeable fluorescence response upon addition of BRD4(1). In-gel fluorescence scanning demonstrated that BRD4(1) can be covalently labelled by the probe. Moreover, the probe was shown to selectively detect BRD4(1) over other proteins. We envision that the probe developed in this study will provide a useful tool to further investigate the biological roles of BRDs.展开更多
In this study,we developed a facile one-step hydrothermal process that allows to synthesize high-purity V0_(2)(M/R)nanoparticles with various morphologies such as nanorods,nanogranules,nanoblocks,and nanospheres.W dop...In this study,we developed a facile one-step hydrothermal process that allows to synthesize high-purity V0_(2)(M/R)nanoparticles with various morphologies such as nanorods,nanogranules,nanoblocks,and nanospheres.W dopants are successfully implanted in V02(M/R)unit cells with high doping efficiency,which allows to regulate the size,morphology,and phase of obtained nanoparticles.The underlying regulation mechanism is presented in detail to reveal how hydrothermal products vary with W doping contents,which provides a synthetic strategy for the preparation of shape-controlling V02(M/R)nanoparticles with high purity to satisfy different specific demands for corresponding applications in the field of thermochromic smart windows.展开更多
Traditional cooling systems have been posing a significant challenge to the global energy crisis and climate change due to the high energy consumption of the cooling process.In recent years,the emerging daytime radiat...Traditional cooling systems have been posing a significant challenge to the global energy crisis and climate change due to the high energy consumption of the cooling process.In recent years,the emerging daytime radiative cooling provides a promising solution to address the bottleneck of traditional cooling technology by passively dissipating heat radiation to outer space without any energy consumption through the atmospheric transparency window(8~13μm).Whereas its stringent optical criteria require sophisticated and high cost fabrication producers,which hinders the applicability of radiative cooling technology.Many efforts have been devoted to develop high-efficiency and low-cost daytime radiative cooling technologies for practical application,including the nanophotonics based artificial strategy and bioinspired strategy.In order to systematically summarize the development and latest advance of daytime radiative cooling to help developing the most promising approach,here in this paper we will review and compare the two typical strategies on exploring the prospect approach for applicable radiative cooling technology.We will firstly sketch the fundamental of radiative cooling and summarize the common methods for construction radiative cooling devices.Then we will put an emphasis on the summarization and comparison of the two strategies for designing the radiative cooling device,and outlook the prospect and extending application of the daytime radiative cooling technology.展开更多
Proximity labeling catalyzed by promiscuous enzymes,such as APEX2,has emerged as a powerful approach to characterize multiprotein complexes and protein-protein interactions.However,current methods depend on the expres...Proximity labeling catalyzed by promiscuous enzymes,such as APEX2,has emerged as a powerful approach to characterize multiprotein complexes and protein-protein interactions.However,current methods depend on the expression of exogenous fusion proteins and cannot be applied to identify proteins surrounding post-translationally modified proteins.To address this limitation,we developed a new method to label proximal proteins of interest by antibody-mediated protein A-ascorbate peroxidase 2(pA-APEX2) labeling(AMAPEX).In this method,a modified protein is bound in situ by a specific antibody,which then tethers a pA-APEX2 fusion protein.Activation of APEX2 labels the nearby proteins with biotin;the biotinylated proteins are then purified using streptavidin beads and identified by mass spectrometry.We demonstrated the utility of this approach by profiling the proximal proteins of histone modifications including H3 K27 me3,H3 K9 me3,H3 K4 me3,H4 K5 ac,and H4 K12 ac,as well as verifying the co-localization of these identified proteins with bait proteins by published ChIP-seq analysis and nucleosome immunoprecipitation.Overall,AMAPEX is an efficient method to identify proteins that are proximal to modified histones.展开更多
Bubbles are pervasive in aqueous media,and on account of numerous advantages of tiny bubbles,efficient bubble splitting is favorable in a wide range of applications.However,underwater bubble splitting faces a lot of c...Bubbles are pervasive in aqueous media,and on account of numerous advantages of tiny bubbles,efficient bubble splitting is favorable in a wide range of applications.However,underwater bubble splitting faces a lot of challenges because bubbles tend to coalesce during the rising due to the action of buoyancy and surface energy,and the consumption of considerable external energy is needed.Inspired by the bubble bursting phenomenon on the feathers of high‐speed swimming penguins,we proposed a new bubble splitting strategy based on the energy conversion of bubble transportation on superhydrophobic open pathways.A porous superhydrophobic coating was first developed via a bubbletemplate assisted fabrication method,which provides hierarchical micro/nanostructures and robust air plastron.Gas bubbles can transport along the superhydrophobic open pathways without perturbation,and split into smaller ones by taking advantage of the potential energy contributed by buoyancy.By controlling the superhydrophobic pathway,the size of the split bubbles can be controlled precisely.We also demonstrated that a bubble splitting device could be applied in underwater reactions where an enhanced gas−liquid mass transfer is desired.This bubble splitting strategy may offer new prospects for underwater bubble manipulation and unfold a potential in many bubble‐involved fields.展开更多
Extensive work have been done to harvest untapped water energy in formats of raindrops,flows,waves,and others.However,attaining stable and efficient electricity generation from these low-frequency water kinetic energi...Extensive work have been done to harvest untapped water energy in formats of raindrops,flows,waves,and others.However,attaining stable and efficient electricity generation from these low-frequency water kinetic energies at both individual device and large-scale system level remains challenging,partially owing to the difficulty in designing a unit that possesses stable liquid and charge transfer properties,and also can be seamlessly integrated to achieve preferential collective performances without the introduction of tortuous wiring and redundant node connection with external circuit.Here,we report the design of water electricity generators featuring the combination of lubricant layer and transistor-like electrode architecture that endows enhanced electrical performances in different working environments.Such a design is scalable in manufacturing and suitable for facile integration,characterized by significant reduction in the numbers of wiring and nodes and elimination of complex interfacing problems,and represents a significant step toward large-scale,real-life applications.展开更多
基金This study was supported by General Research Fund from the Research Grants Council of the Hong Kong SAR(Grant Nos.CityU 11201020 and 11207321)the National Natural Science Foundation of China(Grant No.51779213)as well as Contract Research Project(Ref.No.CEDD STD-30-2030-1-12R)from the Geotechnical Engineering Office.
文摘Predicting the constitutive response of granular soils is a fundamental goal in geomechanics.This paper presents a machine learning(ML)framework for the prediction of the stress-strain behaviour and shearinduced contact fabric evolution of an idealised granular material subject to triaxial shearing.The MLbased framework is comprised of a set of mini-triaxial tests which provide a benchmark for the setup and validation of the discrete element method(DEM)model of the granular materials,a parametric DEM simulation programme of virtual triaxial tests which provides datasets of micro-and macro-mechanical information,as well as a multi-layer perceptron(MLP)neural network which is trained and tested using the DEM-based datasets.The ML model only requires the initial void ratio of the granular sample as the input for predicting its constitutive response.The excellent agreement between the ML model prediction and experimental test and DEM simulation results indicates that the MLebased modelling approach is capable of capturing accurately the effects of initial void ratio on the constitutive behaviour of idealised granular materials,bypassing the need to incorporate the complex micromechanics underlying the macroscopic mechanical behaviour of granular materials.Lastly,a detailed comparison between the used MLP model and long short-term memory(LSTM)model was made from the perspective of technical algorithm,prediction accuracy,and computational efficiency.
基金supported by the General Research Fund from the Research Grant Council of the Hong Kong SAR,China(Grant Nos.CityU 11201020 and CityU 11207321)the National Science Foundation of China(Grant No.42207185)+1 种基金the Contract Research Project from the Geotechnical Engineering Office of the Civil Engineering Development Department of Hong Kong SAR,China(Project Ref.No.CEDD STD-30-2030-1-12R)the BL13W beamline of Shanghai Synchrotron Radiation Facility(SSRF)。
文摘Discrete element method(DEM)has been widely utilised to model the mechanical behaviours of granular materials.However,with simplified particle morphology or rheology-based rolling resistance models,DEM failed to describe some responses,such as the particle kinematics at the grain-scale and the principal stress ratio against axial strain at the macro-scale.This paper adopts a computed tomography(CT)-based DEM technique,including particle morphology data acquisition from micro-CT(mCT),spherical harmonic-based principal component analysis(SH-PCA)-based particle morphology reconstruction and DEM simulations,to investigate the capability of DEM with realistic particle morphology for modelling granular soils’micro-macro mechanical responses with a consideration of the initial packing state,the morphological gene mutation degree,and the confining stress condition.It is found that DEM with realistic particle morphology can reasonably reproduce granular materials’micro-macro mechanical behaviours,including the deviatoric stressevolumetric straineaxial strain response,critical state behaviour,particle kinematics,and shear band evolution.Meanwhile,the role of multiscale particle morphology in granular soils depends on the initial packing state and the confining stress condition.For the same granular soils,rougher particle surfaces with a denser initial packing state and a higher confining stress condition result in a higher degree of shear strain localisation.
基金sponsored by the National Natural Science Foundation of China(5197418151574164)+5 种基金the Iron and Steel Joint Research Found of National Natural Science Foundation and China Baowu Steel Group Corporation Limited(U1860203)the Shanghai Rising-Star Program(19QA1403600)China Postdoctoral Science Foundation(2019M661462)the Shanghai Postdoctoral Excellence Program(2018079)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher learning(TP2019041)the CAS Interdisciplinary Innovation Team and High Performance Computing Center,Shanghai University for financial support。
文摘Porous active core-shell carbon material with excellent synergistic effect has been regarded as a prospective material for supercapacitors.Herein,we report an integrated method for the facile synthesis of carbide-derived carbon(CDC)encapsulated with porous N-doped carbon(CDC@NC)towards highperformance supercapacitors.Polydopamine(PDA)as nitrogen and carbon sources was simply coated on SiC nanospheres to form SiC@PDA,which was then directly transformed into CDC@NC via a onestep molten salt electro-etching/in-situ doping process.The synthesized CDC@NC with hierarchically porous structure has a high specific surface area of 1191 m^(2) g^(-1).The CDC core and NC shell are typical amorphous carbon and more ordered N-doped carbon,respectively.Benefitting from its unique dual porous structures,the CDC@NC demonstrates high specific capacitances of 255 and 193 F g^(-1) at 0.5 and20 A g^(-1),respectively.The reaction mechanism of the electro-etching/in-situ doping process has also been investigated through experimental characterizations and theoretical density functional theory calculations.It is suggested that the molten salt electro-etching/in-situ doping strategy is promising for the synthesis of active core-shell porous carbon materials with synergistic properties for supercapacitors without the need for additional doping/activation processes.
基金the financial support of the project from the National Natural Science Foundation of China(No.61904141)the funding of Natural Science Foundation of Shaanxi Province(No.2020JQ-295)+3 种基金the Key Research and Development Program of Shaanxi(Program No.2020GY-252)National Key Laboratory of Science and Technology on Vacuum Technology and Physics(HTKJ2019KL510007)City University of Hong Kong(Project Nos.7005070 and 9667153)Shenzhen Science and Technology Innovation Committee under the Grant JCYJ20170818103206501。
文摘Developing flexible sensors with high working performance holds intense interest for diverse applications in leveraging the Internet-of-things(IoT)infrastructures.For flexible piezoresistive sensors,traditionally most efforts are focused on tailoring the sensing materials to enhance the contact resistance variation for improving the sensitivity and working range,and it,however,remains challenging to simultaneously achieve flexible sensor with a linear working range over a high-pressure region(>100 kPa)and keep a reliable sensitivity.Herein,we devised a laserengraved silver-coated fabric as"soft"sensor electrode material to markedly advance the flexible sensor's linear working range to a level of 800 kPa with a high sensitivity of 6.4 kPa^-1 yet a fast response time of only 4 ms as well as long-time durability,which was rarely reported before.The integrated sensor successfully routed the wireless signal of pulse rate to the portable smartphone,further demonstrating its potential as a reliable electronic.Along with the rationally building the electrode instead of merely focusing on sensing materials capable of significantly improving the sensor's performance,we expect that this design concept and sensor system could potentially pave the way for developing more advanced wearable electronics in the future.
基金supported by the Research Grant Council(RGC)of Hong Kong(11212321,11217922,and ECS-21212720)Basic and Applied Basic Research Fund of Guangdong,ChinaScience,Technology and Innovation Committee of Shenzhen(SGDX20210823104001011)。
基金supported by the General Research Fund(Nos.CityU 11201020 and CityU 11207321)the Research Grant Council of the Hong Kong Special Administrative Region(SAR),China+2 种基金the Contract Research Project(No.9211295)the Geotechnical Engineering Office of the Civil Engineering Development Department of the Government of the Hong Kong SARthe financial support from the Hong Kong PhD Fellowship Scheme(HKPFS)。
文摘In this paper,the X-ray micro-computed tomography(X-rayμCT),spherical harmonical-based principal component analysis(SH-PCA),and discrete element method(DEM)were incorporated to generate virtual samples with morphological gene mutation at different length scales.All samples were subjected to axial compression and constant confining stress.The effects of multiscale particle morphology on the stress-strain and energy storage/dissipation responses of granular soils were investigated.It is found that:(a)the effects of particle morphology on the initial stiffness,stress-strain,volumetric strain,and frictional energy dissipation behaviours are more pronounced for looser samples than for denser ones;(b)among different length scales,the particle morphology at the local roundness-level outperforms the one at the general form-level in dictating the macro-scale responses of granular soils;(c)the energy dissipation of a granular assemblage is a result of competition between particle morphology and initial void ratio.
基金support by the Shenzhen-Hong Kong-Macao Science and Technology Project(Category C)sponsored by the Science Technology and Innovation Committee of Shenzhen Municipality(SGDX20201103093003017)Shenzhen Key Basic Research Project(JCYJ20200109114827177)Hong Kong RGC General Research Fund(CityU 11216421).
基金This work was supported by Hong Kong Research Grant Council(RGC)(Nos.CityU 11207416 and CityU 11306520)City University of Hong Kong(No.9667194)the National Natural Science Foundation of China(No.11922215).
文摘Due to the enhanced ambient structural stability and excellent optoelectronic properties, all-inorganic metal halide perovskite nanowires have become one of the most attractive candidates for flexible electronics, photovoltaics and optoelectronics. Their elastic property and mechanical robustness become the key factors for device applications under realistic service conditions with various mechanical loadings. Here, we demonstrate that high tensile elastic strain (∼ 4% to ∼ 5.1%) can be achieved in vapor-liquid-solid-grown single-crystalline CsPbBr_(3) nanowires through in situ scanning electron microscope (SEM) buckling experiments. Such high flexural elasticity can be attributed to the structural defect-scarce, smooth surface, single-crystallinity and nanomechanical size effect of CsPbBr_(3) nanowires. The mechanical reliability of CsPbBr_(3) nanowire-based flexible photodetectors was examined by cyclic bending tests, with no noticeable performance deterioration observed after 5,000 cycles. The above results suggest great application potential for using all-inorganic perovskite nanowires in flexible electronics and energy harvesting systems.
基金supported by the Key Laboratory Funding Scheme of Shenzhen Municipal Governmentthe AOE about MERIT project from University Grant Committee of Hong Kong (Grant No. AOE/P-04/2004)the Natural Science Foundation of Hebei Province (Grant No. B2009000161)
文摘This study has investigated the effects of gold nanoparticles (Au NPs) on the proliferation, differentiation, and mineralization of a murine preosteoblast cell line MC3T3-E1 in vitro. The results show that Au NPs with diameters of both 20 and 40 nm promoted the proliferation, differentiation, and mineralization of MC3T3-E1 cells in a time- and dose-dependent manner at the concentra-tions of 1.5×10-5, 3.0×10-5, and 1.5×10-4 μmol/L. The reverse transcriptase polymerase chain reaction (RT-PCR) indicates that the expressions of runt-related transcription factor 2 (Runx2), bone morphogenetic protein 2 (BMP-2), alkaline phosphatase (ALP), and osteocalcin (OCN) genes increased after the 20 and 40 nm Au NP treatments, and the expression levels were higher than those of the NaF group. The above results suggest that Au NPs have the potential to promote the osteogenic differentiation and miner- alization of MC3T3-E1 cells and the particle size plays a significant role in the process. Runx2, BMP-2, ALP, and OCN genes may interact with each other, further stimulating the osteogenic differentiation of MC3T3-E1 cells.
基金the Research Grants Council of the Hong Kong Special Administrative Region of China (GRF No. CityU11216515)City University of Hong Kong (Nos. 7005070 and 9667153)+1 种基金Shenzhen Science and Technology Innovation Committee under the grant JCYJ20170818103206501the Natural Science Basic Research Plan in Shaanxi Province of China (No. 2017JM5003)
文摘3D printing-based supercapacitors have been extensively explored,yet the rigid rheological requirement for corresponding ink preparation significantly limits the manufacturing of true 3D architecture in achieving superior energy storage.We proposed the stereolithographic technique to fabricate the metallic composite lattices with octet-truss arrangement by using electroless plating and engineering the 3D hierarchically porous graphene onto the scaffolds to build the hierarchically cellular lattices in quasi-solid supercapacitor application.The supercapacitor device that is composed of composite lattices span several pore size orders from nm to mm holds promising behavior on the areal capacitance(57.75 mF cm-2),rate capability(70% retention,2-40 mA cm-2),and long lifespan(96% after 5000 cycles),as well as superior energy density of 0.008 mWh cm-2,which are comparable to the state-of-the-art carbon-based supercapacitor.By synergistically combining this facile stereolithographic 3D printing technology with the hierarchically porous graphene architecture,we provide a novel route of manufacturing energy storage device as well as new insight into building other high-performance functional electronics.
基金the support from the Research Grants Council of the Hong Kong Special Administrative Region,China(Grant RFS2021-1S05)the National Natural Science Foundation of China(Grant 11922215)+1 种基金the funding from the National Natural Science Foundation of China(Grant 11902200)the Science and Technology Commission of Shanghai Municipality(Grant19YF1433600)。
文摘Diamond,as an ultra-wide bandgap semiconductor,has become a promising candidate for next-generation microelec-tronics and optoelectronics due to its numerous advantages over conventional semiconductors,including ultrahigh carrier mo-bility and thermal conductivity,low thermal expansion coefficient,and ultra-high breakdown voltage,etc.Despite these ex-traordinary properties,diamond also faces various challenges before being practically used in the semiconductor industry.This review begins with a brief summary of previous efforts to model and construct diamond-based high-voltage switching diodes,high-power/high-frequency field-effect transistors,MEMS/NEMS,and devices operating at high temperatures.Following that,we will discuss recent developments to address scalable diamond device applications,emphasizing the synthesis of large-area,high-quality CVD diamond films and difficulties in diamond doping.Lastly,we show potential solutions to modulate diamond’s electronic properties by the“elastic strain engineering”strategy,which sheds light on the future development of diamond-based electronics,photonics and quantum systems.
基金This study was supported by the General Research Fund(No.CityU 11272916)from the Research Grant Council of the Hong Kong SAR,Research from the National Science Foundation of China(Grant No.51779213)+2 种基金the Open-Research from State Key Laboratory of Civil Engineering Disaster Prevention of Tongji University(No.SLDRCE15-04)the BLI3W beam-line of Shanghai Synchrotron Radiation Facility(SSRF)The authors would like to thank Dr.Edward Ando in Universite Grenoble Alpes for providing his PhD thesis.
文摘The development of a miniature triaxial apparatus is presented.In conjunction with an X-ray microtomography(termed as X-ray fiCT hereafter)facility and advanced image processing techniques,this apparatus can be used for in situ investigation of the micro-scale mechanical behavior of granular soils under shear.The apparatus allows for triaxial testing of a miniature dry sample with a size of 8 mm x 16 mm(diameter x height).In situ triaxial testing of a 0.4-0.8 mm Leighton Buzzard sand(LBS)under a constant confining pressure of 500 kPa is presented.The evolutions of local porosities(i.e.,the porosities of regions associated with individual particles),particle kinematics(i.e.,particle translation and particle rotation)of the sample during the shear are quantitatively studied using image processing and analysis techniques.Meanwhile,a novel method is presented to quantify the volumetric strain distribution of the sample based on the results of local porosities and particle tracking.It is found that the sample,with nearly homogenous initial local porosities,starts to exhibit obvious inhomogeneity of local porosities and localization of particle kinematics and volumetric strain around the peak of deviatoric stress.In the post-peak shear stage,large local porosities and volumetric dilation mainly occur in a localized band.The developed triaxial apparatus,in its combined use of X-ray|iCT imaging techniques,is a powerful tool to investigate the micro-scale mechanical behavior of granular soils.
基金supported by General Research Fund Grant(Nos.CityU 11201020 and CityU 11213517)from the Research Grants Council of the Hong Kong SARResearch Grant(No.51779213)from the National Science Foundation of China.
文摘In this study,discrete element method(DEM)simulations of a biaxial test were used to examine the effect of particle roundness on the mechanical behavior of sands at both the macro and micro scales.First,a stack of microcomputed tomography images were binarized,segmented,and labeled using advanced image processing and analysis techniques.Second,a spherical harmonic(SH)analysis,which involves a complete set of orthogonal functions,was implemented to rebuild the natural particle shape.Then,five templates of virtual particles were built in a DEM simulation,four of which were obtained from SH degrees of 3,8,12,and 15,and one template was an elementary sphere.A flexible membrane was numerically generated to allow the material to deform freely under a prescribed confining stress.Finally,the effect of particle roundness on the mechanical properties of granular materials was investigated and discussed.Two shear bands were found to intersect,forming an X shape in both the rotation and displacement fields.Moreover,a lower particle roundness results in higher deviatoric stress and stronger dilation in the volumetric change.A decrease in particle roundness leads to less rotation of particles despite a higher displacement value.In addition,a larger SH degree leads to smaller normalized contact forces of the particles.This implies that decreasing the roundness results in higher anisotropy of the contact forces.
基金Projects(61922093,U1813211) supported by the National Natural Science Foundation of ChinaProjects(SGDX20201103093003017,JCYJ20200109114827177) supported by Shenzhen Key Basic Research Project,China。
基金the financial support from the National Natural Science Foundation of China (No. 21572190)the Hong Kong Early Career Scheme Grant (No. 21300714)the City University of Hong Kong Grant (No. 9667147)
文摘Lysine acetylation is one of the most prevalent and important posttranslational modifications(PTMs) in proteins. The process can be recognized by bromodomains(BRDs), which are a class of proteininteraction modules involved in chromatin remodeling and transcriptional activation. The development of BRD fluorescent probes will be useful for monitoring the activity of BRDs in living cells as well as aiding inhibitor development. Herein we designed a peptide-based probe based on the proximity-induced protein conjugation reaction. The peptide-based probe is capable of covalently and selectively reacting with the unique cysteine residue in the bromodomain through proximity effect. Our experimental data showed that the probe displayed noticeable fluorescence response upon addition of BRD4(1). In-gel fluorescence scanning demonstrated that BRD4(1) can be covalently labelled by the probe. Moreover, the probe was shown to selectively detect BRD4(1) over other proteins. We envision that the probe developed in this study will provide a useful tool to further investigate the biological roles of BRDs.
文摘In this study,we developed a facile one-step hydrothermal process that allows to synthesize high-purity V0_(2)(M/R)nanoparticles with various morphologies such as nanorods,nanogranules,nanoblocks,and nanospheres.W dopants are successfully implanted in V02(M/R)unit cells with high doping efficiency,which allows to regulate the size,morphology,and phase of obtained nanoparticles.The underlying regulation mechanism is presented in detail to reveal how hydrothermal products vary with W doping contents,which provides a synthetic strategy for the preparation of shape-controlling V02(M/R)nanoparticles with high purity to satisfy different specific demands for corresponding applications in the field of thermochromic smart windows.
文摘Traditional cooling systems have been posing a significant challenge to the global energy crisis and climate change due to the high energy consumption of the cooling process.In recent years,the emerging daytime radiative cooling provides a promising solution to address the bottleneck of traditional cooling technology by passively dissipating heat radiation to outer space without any energy consumption through the atmospheric transparency window(8~13μm).Whereas its stringent optical criteria require sophisticated and high cost fabrication producers,which hinders the applicability of radiative cooling technology.Many efforts have been devoted to develop high-efficiency and low-cost daytime radiative cooling technologies for practical application,including the nanophotonics based artificial strategy and bioinspired strategy.In order to systematically summarize the development and latest advance of daytime radiative cooling to help developing the most promising approach,here in this paper we will review and compare the two typical strategies on exploring the prospect approach for applicable radiative cooling technology.We will firstly sketch the fundamental of radiative cooling and summarize the common methods for construction radiative cooling devices.Then we will put an emphasis on the summarization and comparison of the two strategies for designing the radiative cooling device,and outlook the prospect and extending application of the daytime radiative cooling technology.
基金supported by the National Key R&D Program of China(Grant No.2019YFA0903803)the Major Program of National Natural Science Foundation of China(Grant No.32090031)+10 种基金the General Program of National Natural Science Foundation of China(Grant Nos.31971354 and 32070610)the National Natural Science Foundation of China for Young Scholars(Grant No.32000580)the Guangdong Province Fund for Distinguished Young Scholars,China(Grant No.2021B1515020109)the Key Project from Natural Science Foundation of Guangdong Province,China(Grant No.2020B1515120034)the Guangdong Provincial Key Laboratory of Synthetic Genomics,China(Grant No.2019B030301006)the Shenzhen Key Laboratory of Synthetic Genomics,China(Grant No.ZDSYS201802061806209)the Project from Shenzhen Science and Technology Innovation Committee,China(Grant No.JCYJ20170818164014753)the Mayo Clinic Cancer Center Eagles Cancer Fund awarded to ZWthe Mayo Clinic Cancer Center Hematologic Malignancies Program awarded to ZWthe Mayo Clinic division of Hematology awarded to ZWthe Mayo Clinic Center for Biomedical Discovery awarded to SMO,United States。
文摘Proximity labeling catalyzed by promiscuous enzymes,such as APEX2,has emerged as a powerful approach to characterize multiprotein complexes and protein-protein interactions.However,current methods depend on the expression of exogenous fusion proteins and cannot be applied to identify proteins surrounding post-translationally modified proteins.To address this limitation,we developed a new method to label proximal proteins of interest by antibody-mediated protein A-ascorbate peroxidase 2(pA-APEX2) labeling(AMAPEX).In this method,a modified protein is bound in situ by a specific antibody,which then tethers a pA-APEX2 fusion protein.Activation of APEX2 labels the nearby proteins with biotin;the biotinylated proteins are then purified using streptavidin beads and identified by mass spectrometry.We demonstrated the utility of this approach by profiling the proximal proteins of histone modifications including H3 K27 me3,H3 K9 me3,H3 K4 me3,H4 K5 ac,and H4 K12 ac,as well as verifying the co-localization of these identified proteins with bait proteins by published ChIP-seq analysis and nucleosome immunoprecipitation.Overall,AMAPEX is an efficient method to identify proteins that are proximal to modified histones.
基金Shenzhen Basic Research Program,Grant/Award Number:JCYJ20210324134009024City University of Hong Kong,Grant/Award Number:9667203+1 种基金Collaborative Research Fund(CRF)Hong Kong,Grant/Award Number:C1006‐20WFResearch Grant Council of Hong Kong,Grant/Award Number:CityU11305219。
文摘Bubbles are pervasive in aqueous media,and on account of numerous advantages of tiny bubbles,efficient bubble splitting is favorable in a wide range of applications.However,underwater bubble splitting faces a lot of challenges because bubbles tend to coalesce during the rising due to the action of buoyancy and surface energy,and the consumption of considerable external energy is needed.Inspired by the bubble bursting phenomenon on the feathers of high‐speed swimming penguins,we proposed a new bubble splitting strategy based on the energy conversion of bubble transportation on superhydrophobic open pathways.A porous superhydrophobic coating was first developed via a bubbletemplate assisted fabrication method,which provides hierarchical micro/nanostructures and robust air plastron.Gas bubbles can transport along the superhydrophobic open pathways without perturbation,and split into smaller ones by taking advantage of the potential energy contributed by buoyancy.By controlling the superhydrophobic pathway,the size of the split bubbles can be controlled precisely.We also demonstrated that a bubble splitting device could be applied in underwater reactions where an enhanced gas−liquid mass transfer is desired.This bubble splitting strategy may offer new prospects for underwater bubble manipulation and unfold a potential in many bubble‐involved fields.
基金support of the Research Grants Council of Hong Kong(nos.C1006-20WF and 11213320)the Tencent Foundation through the XPLORER PRIZE,the Innovation and Technology Council(no.9440248)+1 种基金the National Natural Science Foundation of China(grant nos.51975502 and 21621001)the 111 Project(B17020).
文摘Extensive work have been done to harvest untapped water energy in formats of raindrops,flows,waves,and others.However,attaining stable and efficient electricity generation from these low-frequency water kinetic energies at both individual device and large-scale system level remains challenging,partially owing to the difficulty in designing a unit that possesses stable liquid and charge transfer properties,and also can be seamlessly integrated to achieve preferential collective performances without the introduction of tortuous wiring and redundant node connection with external circuit.Here,we report the design of water electricity generators featuring the combination of lubricant layer and transistor-like electrode architecture that endows enhanced electrical performances in different working environments.Such a design is scalable in manufacturing and suitable for facile integration,characterized by significant reduction in the numbers of wiring and nodes and elimination of complex interfacing problems,and represents a significant step toward large-scale,real-life applications.
