Solid-state batteries have been considered as a good choice for substituting traditional batteries with liquid electrolytes because of their high energy density and safe property.However,a little amount of flammable n...Solid-state batteries have been considered as a good choice for substituting traditional batteries with liquid electrolytes because of their high energy density and safe property.However,a little amount of flammable non-aqueous liquid electrolyte or polymer electrolyte is usually required to improve the interfacial contact,which is adverse to safety.Here,a nonflammable gel is prepared by hydrogen-bond interaction and applied as an interfacial layer to improve the performance of solid-state batteries.The prepared multilayer hybrid electrolyte(MHE)composed of gel and CPE shows a wide electrochemical window(5.3 V vs Li/Li+),high ionic transference number(0.57),and ionic conductivity(7.18×10^(−4) S cm^(−1))at room temperature.Thus,the assembled Li symmetric cell with MHE can cycle over 650 h at 0.5 mA cm^(−2) with a lower overpotential of~61 mV.The LiFePO_(4)|MHE|Li cell exhibits a higher discharge capacity of 107.8 mAh g−1 even cycled at 5 C.It also shows superior capacity retention of 96.4%after 1000 cycles at 0.5 C.This work provides a promising strategy for designing high-performance solid-state batteries.展开更多
Beyond regulation of male sexual function, the increasing evidence shows that androgens and androgen receptor (AR) have a variety of physiological and pathological effects on the skin. Skin cells express all androgen ...Beyond regulation of male sexual function, the increasing evidence shows that androgens and androgen receptor (AR) have a variety of physiological and pathological effects on the skin. Skin cells express all androgen metabolizing enzymes that are required for independent skin androgen synthesis and the development of hyperandrogenic related disorders such as acne, hirsutism and androgenetic alopecia. Targeting various elements of androgen function and metabolism is the major goal of medication design for the treatment of androgen-related diseases. Antiandrogen drugs such as clascoterone, flutamide could improve conditions. Even though the involvement of androgens and AR in skin diseases has been investigated for a long time, their molecular mechanisms in skin disorders remain largely insufficient. In this review, recent studies and advances on the role of androgens/AR in several skin-related diseases and their therapeutics are systematically summarized.展开更多
This paper presents a new fall detection method of etderly people in a room environment based on shape analysis of 3D depth images captured by a Kinect sensor. Depth images are pre- processed by a median filter both f...This paper presents a new fall detection method of etderly people in a room environment based on shape analysis of 3D depth images captured by a Kinect sensor. Depth images are pre- processed by a median filter both for background and target. The sithouette of moving individual in depth images is achieved by a subtraction method for background frames. The depth images are converted to disparity map, which is obtained by the horizontal and vertical projection histogram statistics. The initial floor plane information is obtained by V disparity map, and the floor ptane equation is estimated by the least square method. Shape information of human subject in depth images is analyzed by a set of moment functions. Coefficients of ellipses are calculated to determine the direction of individual The centroids of the human body are catculated and the angle between the human body and the floor plane is calculated. When both the distance from the centroids of the human body to the floor plane and the angle between the human body and the floor plane are tower than some threshotds, fall incident will be detected. Experiments with different failing direction are performed. Experimental results show that the proposed method can detect fall incidents effectively.展开更多
Projection micro stereolithography(PμSL)has emerged as a powerful three-dimensional(3D)printing technique for manufacturing polymer structures with micron-scale high resolution at high printing speed,which enables th...Projection micro stereolithography(PμSL)has emerged as a powerful three-dimensional(3D)printing technique for manufacturing polymer structures with micron-scale high resolution at high printing speed,which enables the production of customized 3D microlattices with feature sizes down to several microns.However,the mechanical properties of as-printed polymers were not systemically studied at the relevant length scales,especially when the feature sizes step into micron/sub-micron level,limiting its reliable performance prediction in micro/nanolattice and other metamaterial applications.In this work,we demonstrate that PμSL-printed microfibers could become stronger and significantly more ductile with reduced size ranging from 20μm to 60μm,showing an obvious size-dependent mechanical behavior,in which the size decreases to 20μm with a fracture strain up to~100%and fracture strength up to~100 MPa.Such size effect enables the tailoring of the material strength and stiffness of PμSL-printed microlattices over a broad range,allowing to fabricate the microlattice metamaterials with desired/tunable mechanical properties for various structural and functional applications.展开更多
The carbonate-free fraction of 20 surface sediments collected from the ultraslow-spreading Southwest Indian Ridge(SWIR) was studied by grain size analysis and mineralogical analysis with X-ray powder diffraction(XRD),...The carbonate-free fraction of 20 surface sediments collected from the ultraslow-spreading Southwest Indian Ridge(SWIR) was studied by grain size analysis and mineralogical analysis with X-ray powder diffraction(XRD),stereo microscopy and scanning electron microscopy(SEM). The characteristics of the carbonate-free fraction of the sediments were obtained, and related influential factors were discussed. The results show that the mean grain size of this fraction is in 1.96Φ–8.19Φ, with poorly sorting and unimodal, bimodal or irregular bimodal distribution patterns. Four grain size end members of the fraction are derived with the End Member Model method. The finest end member EM1 shows a significant contribution of terrigenous materials of the aeolian input and sediment carried by the bottom current. End member EM2 with medium size mainly reflects sediment of a siliceous bioclast origin. EM3 and EM4 are interpreted as representing the coarser volcanic materials related to bedrock weathering or volcanic activities. Multi-provenance is the dominant factor controlling the grain size pattern of the carbonate-free fraction of the sediments in that area. In addition, sediment transport processes such as the bottom current and wind are the minor factors that influence the grain size distribution of the carbonate-free fraction sediments.展开更多
Numerical simulation is known as an effective method for mechanical properties during frozen soil excavation.In order to reveal the development of cutting force,effective stress and cutting fragments in frozen silt du...Numerical simulation is known as an effective method for mechanical properties during frozen soil excavation.In order to reveal the development of cutting force,effective stress and cutting fragments in frozen silt during the cutting process,we introduce an explicit finite element program LS-DYNA to establish a two-dimensional numerical model of the frozen soil cut.We also use the Holmquist-Johnson-Cook(HJC)damage constitutive model for simulating the variation of soil mechanical properties according to the strong dependence between the cutting tool and frozen silt during the process with different cutting depths,angles and velocities.Meanwhile,a series of experimental results are acquired of frozen silt cutting to prove the application of the HJC model during simulation of cutting force variations.The result shows that the cutting force and fragment size are strongly influenced by cutting depths and cutting velocities increased,and the maximum effective stress at points where the tool contacts frozen soil during the cutting process.In addition,when the cutting angle is 52°,the cutting force is the smallest,and the cutting angle is optimum.Thus,the prediction of frozen soil mechanical properties on the cutting process by this model is conducive to selecting machinery equipment in the field.展开更多
With the high-speed development of digital image processing technology, machine vision technology has been widely used in automatic detection of industrial products. A large amount of products can be treated by comput...With the high-speed development of digital image processing technology, machine vision technology has been widely used in automatic detection of industrial products. A large amount of products can be treated by computer instead of human in a shorter time. In the process of automatic detection, edge detection is one of the most commonly used methods. But with the increasing demand for detection precision,traditional pixel-level methods are difficult to meet the requirement, and more subpixel level methods are in the use. This paper presents a new method to detect curved edge with high precision. First, the target area ratio of pixels near the edge is computed by using one-dimensional edge detection method. Second, parabola is used to approximately represent the curved edge. And we select appropriate parameters to obtain accurate results. This method is able to detect curved edges in subpixel level, and shows its practical effectiveness in automatic measure of products with arc shape in large industrial scene.展开更多
Background:While type 2 diabetes mellitus(T2DM)is considered a putative causal risk factor for coronary artery disease(CAD),the intrinsic link underlying T2DM and CAD is not fully understood.We aimed to highlight the ...Background:While type 2 diabetes mellitus(T2DM)is considered a putative causal risk factor for coronary artery disease(CAD),the intrinsic link underlying T2DM and CAD is not fully understood.We aimed to highlight the importance of integrated care targeting both diseases by investigating the phenotypic and genetic relationships between T2DM and CAD.Methods:We evaluated phenotypic associations using data from the United Kingdom Biobank(N=472,050).We investigated genetic relationships by leveraging genomic data conducted in European ancestry for T2DM,with and without adjustment for body mass index(BMI)(T2DM:N_(case)/N_(control)=74,124/824,006;T2DM adjusted for BMI[T2DM_(adj)BMI]:N_(case)/N_(control)=50,409/523,897)and for CAD(N_(case)/N_(control)=181,522/984,168).We performed additional analyses using genomic data conducted in multiancestry individuals for T2DM(N_(case)/N_(control)=180,834/1,159,055).Results:Observational analysis suggested a bidirectional relationship between T2DM and CAD(T2DM→CAD:hazard ratio[HR]=2.12,95%confidence interval[CI]:2.01–2.24;CAD→T2DM:HR=1.72,95%CI:1.63–1.81).A positive overall genetic correlation between T2DM and CAD was observed(r_(g)=0.39,P=1.43×10^(-75)),which was largely independent of BMI(T2DM_(adj)BMI–CAD:r_(g)=0.31,P=1.20×10^(–36)).This was corroborated by six local signals,among which 9p21.3 showed the strongest genetic correlation.Cross-trait meta-analysis replicated 101 previously reported loci and discovered six novel pleiotropic loci.Mendelian randomization analysis supported a bidirectional causal relationship(T2DM→CAD:odds ratio[OR]=1.13,95%CI:1.11-1.16;CAD→T2DM:OR=1.12,95%CI:1.07-1.18),which was confirmed in multiancestry individuals(T2DM→CAD:OR=1.13,95%CI:1.10-1.16;CAD→T2DM:OR=1.08,95%CI:1.04-1.13).This bidirectional relationship was significantly mediated by systolic blood pressure and intake of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors,with mediation proportions of 54.1%(95%CI:24.9-83.4%)and 90.4%(95%CI:29.3-151.5%),respectively.Conclusion:Our observational and genetic analyses demonstrated an intrinsic bidirectional relationship between T2DM and CAD and clarified the biological mechanisms underlying this relationship.展开更多
To numerically study the impact of total temperature distortion on a transonic compressor with reduced computational costs,a Body-Force Model(BFM)is developed.Firstly,the interactions between the distorted flow and th...To numerically study the impact of total temperature distortion on a transonic compressor with reduced computational costs,a Body-Force Model(BFM)is developed.Firstly,the interactions between the distorted flow and the compressor are analyzed using full-annulus Unsteady Reynolds-Averaged Navier-Stokes(URANS)results and the orbit method.It is found that the induced swirl distortion and the mass flux nonuniformity are intensified in the compressor upstream flow field.A correction factor is thus added to the BFM to account for the effect of the induced swirl,which is crucial for the accurate representation of distortion transfer in the intake.Then,steady simulations with large-amplitude 180circumferential total temperature distortion are performed using the developed BFM.It is shown that the distorted compressor map simulated with the BFM matches well with URANS results.The circumferential phase shift of total temperature and the generation of the additional total pressure distortion across the rotor are in line with the time-averaged URANS flow field.The compressor upstream effects on the distorted inflow can also be exactly captured.All above-mentioned results demonstrate the BFM developed in this paper can effectively capture the distorted flow features inside the compressor,and significantly reduce the computational costs by five orders of magnitude compared with URANS.展开更多
Acellular dermal matrix(ADM)shows promise for cartilage regeneration and repair.However,an effective decellularization technique that removes cellular components while preserving the extracellular matrix,the transform...Acellular dermal matrix(ADM)shows promise for cartilage regeneration and repair.However,an effective decellularization technique that removes cellular components while preserving the extracellular matrix,the transformation of 2D-ADM into a suitable 3D scaffold with porosity and the enhancement of bioactive and biomechanical properties in the 3D-ADM scaffold are yet to be fully addressed.In this study,we present an innovative decellularization method involving 0.125%trypsin and 0.5%SDS and a 1%Triton X-100 solution for preparing ADM and converting 2D-ADM into 3D-ADM scaffolds.These scaffolds exhibit favorable physicochemical properties,exceptional biocompatibility and significant potential for driving cartilage regeneration in vitro and in vivo.To further enhance the cartilage regeneration potential of 3D-ADM scaffolds.we incorporated porcine-derived small intestinal submucosa(SIS)for bioactivity and calcium sulfate hemihydrate(CSH)for biomechanical reinforcement.The resulting 3D-ADM+SIS scaffolds displayed heightened biological activity,while the 3D-ADM+CSH scaffolds notably bolstered biomechanical strength.Both scaffold types showed promise for cartilage regeneration and repair in vitro and in vivo,with considerable improvements observed in repairing cartilage defects within a rabbit articular cartilage model.In summary,this research introduces a versatile 3D-ADM scaffold with customizable bioactive and biomechanical properties,poised to revolutionize the field of cartilageregeneration.展开更多
The Haber-Bosch process is the most widely used synthetic ammonia technology at present.Since its invention,it has provided an important guarantee for global food security.However,the traditional Haber-Bosch ammonia s...The Haber-Bosch process is the most widely used synthetic ammonia technology at present.Since its invention,it has provided an important guarantee for global food security.However,the traditional Haber-Bosch ammonia synthesis process consumes a lot of energy and causes serious environmental pollution.Under the serious pressure of energy and environment,a green,clean,and sustainable ammonia synthesis route is urgently needed.Electrochemical synthesis of ammonia is a green and mild new method for preparing ammonia,which can directly convert nitrogen or nitrate into ammonia using electricity driven by solar,wind,or water energy,without greenhouse gas and toxic gas emissions.Herein,the basic mechanism of the nitrogen reduction reaction(NRR)to ammonia and nitrate reduction reaction(NO_(3)^(-))to ammonia were discussed.The representative approaches and major technologies,such as lithium mediated electrolysis and solid oxide electrolysis cell(SOEC)electrolysis for NRR,high activity catalyst and advanced electrochemical device fabrication for(NO_(3)^(-))RR and electrochemical ammonia synthesis were summarized.Based on the above discussion and analysis,the main challenges and development directions for electrochemical ammonia synthesis were further proposed.展开更多
Interconnector is a critical component to construct solid oxide cells (SOCs) stack. Oxidation of metallic interconnectors and Cr poisoning caused by oxidation are important factors that lead to long-term performance d...Interconnector is a critical component to construct solid oxide cells (SOCs) stack. Oxidation of metallic interconnectors and Cr poisoning caused by oxidation are important factors that lead to long-term performance degradation of SOCs. Coating on the interconnector surface is an important approach to inhibit the oxidation and Cr migration of the interconnector. Herein, (La0.75Sr0.25)0.95MnO3–δ (LSM) and Mn1.5Co1.5O4 (MCO) are used to fabricate the coatings of interconnector. Two advanced thermal spray technology, atmospheric plasma spraying (APS) and low-pressure plasma spray (LPPS), are adopted for the coating preparation. The electrochemical performance, rising and cooling cycle stability, and Cr diffusion inhibition performance of the coatings are tested and evaluated. The result indicates that MCO can generate more uniform and denser coatings than LSM. In addition, MCO coatings prepared by LPPS shows the best electrochemical performance, rising and cooling cycle stability, and Cr diffusion inhibition. The initial area specific resistance (ASR) is 0.0027 Ω·cm2 at 800 °C. After 4 cooling cycle tests, the ASR increases to 0.0032 Ω·cm2 but lower than other samples. Meanwhile, the relative intense of Cr at the interface of SUS430 with MCO coatings fabricated by LPPS is lower than that of MCO fabricated by APS after 4 rising and cooling cycle operations, showing more favorable Cr diffusion inhibition performance.展开更多
Polyimides are widely used in the MEMS and flexible electronics fields due to their combined physicochemical properties,including high thermal stability,mechanical strength,and chemical resistance values.In the past d...Polyimides are widely used in the MEMS and flexible electronics fields due to their combined physicochemical properties,including high thermal stability,mechanical strength,and chemical resistance values.In the past decade,rapid progress has been made in the microfabrication of polyimides.However,enabling technologies,such as laser-induced graphene on polyimide,photosensitive polyimide micropatterning,and 3D polyimide microstructure assembly,have not been reviewed from the perspective of polyimide microfabrication.The aims of this review are to systematically discuss polyimide microfabrication techniques,which cover flm formation,material conversion,micropatterning,3D microfabrication,and their applications.With an emphasis on polyimide-based flexible MEMS devices,we discuss the remaining technological challenges in polyimide fabrication and possible technological innovations in this field.展开更多
The adaptive feedback control of stability with circumferential inlet distortion has been experimentally investigated in a low-speed,axial compressor.The flat-baffles with different span heights are used to simulate d...The adaptive feedback control of stability with circumferential inlet distortion has been experimentally investigated in a low-speed,axial compressor.The flat-baffles with different span heights are used to simulate different distorted inflow cases.Compared with auto-correlation and root-mean-square analysis,cross-correlation analysis used to predict early stall warning does not depend on the distortion position.Hence,the cross-correlation coefficient was used to monitor the stable status of the compressor and provide the feedback signal in the active control strategy when suffering from different distortions.Based on the stall margin improvement of tip air injection obtained under different distorted inflow cases and the sensitivity analysis of cross-correlation coefficients to injected momentum ratios,tip air injection was adopted as the actuator for adaptive feedback control.The digital signal processing controller was designed and applied to achieve adaptive feedback control in distorted inflow conditions.The results show that the adaptive feedback control of air injection nearly achieves the same stall margin improvement as steady air injection under different distortion intensities with a reduced injection mass flow.Thus,the proposed adaptive feedback control method is ideal for the engine operation with circumferential distorted inflow,which frequently occurs in flight.展开更多
Self-assembly has been widely explored to improve the circularly polarized_(lum)inescence(CPL)activities of molecular chromophores,but it is hard to amplify CPL while maintaining strong emissions.Optically pure,planar...Self-assembly has been widely explored to improve the circularly polarized_(lum)inescence(CPL)activities of molecular chromophores,but it is hard to amplify CPL while maintaining strong emissions.Optically pure,planar-chiral[2.2]paracyclophane(pCp)is one of the most important sources of chirality for electronic and optoelectronic materials,but the photo_(lum)inescence of its derivatives is significantly quenched after forming aggregates.Here we demonstrate that reticulation of pCp chromophores into highly stable Zr(IV)metal-organic frameworks(MOFs)can simultaneously boost the dissymmetry factor(|g_(lum)|)and_(lum)inescence efficiency(Φ_(PL)).Functionalization of pCp enables the synthesis of two tetracarboxylate linkers with different side arms,which are assembled into two highly stable Zr-MOFswith different topological structures.Geometrical constraints and segregated arrangements of the pCp chromophores imposed by the framework inhibit the aggregation-caused quenching effect and boost their CPL behaviors.Both Zr-MOFs display strong CPL emissions,affording|g_(lum)|andΦ_(PL)values of up to 8.3×10^(-3)and 87%,respectively,which are amplified by∼18-and 52-fold compared to the corresponding free ligands.This work highlights the potential of optimizing CPL performances of chiral chromophores by using MOFs as support structures.展开更多
Degradation of organic matter(OM)in sediments is a key link in nutrient cycling and sedimentation processes in lakes.The aim of this study was to explore the degradation of OM in surface sediments of a shallow lake(Ba...Degradation of organic matter(OM)in sediments is a key link in nutrient cycling and sedimentation processes in lakes.The aim of this study was to explore the degradation of OM in surface sediments of a shallow lake(Baiyangdian Lake,China)under seasonal temperature variations.For this,we used the amino acid-based degradation index(DI)and the spatiotemporal distribution characteristics and sources of OM.Sediment OM in the lake mainly originated from freshwater aquatic plants and terrestrial C4 plants.The sediment at some sampling sites was affected by surrounding crops.The organic carbon and total nitrogen contents,and the total hydrolyzed amino acid concentrations in the sediments were highest in summer and lowest in winter.The lowest DI occurred in spring,which indicated that the OM in the surface sediment at this time was highly degraded and relatively stable,and the highest DI occurred in winter,which showed that the sediment was fresh.The water temperature was positively correlated with the organic carbon content(p<0.01)and total hydrolyzed amino acids concentration(p<0.05).Seasonal variations in the overlying water temperature had a large effect on OM degradation in the lake sediments.Our results will facilitate the management and restoration of lake sediments that suffer from endogenous release of OM in a warming climate。展开更多
A typical anthropogenically disturbed urban river polluted by a combination of conventional pollutants(nitrogen and phosphorus pollution)and heavy metals was investigated along a 238 km stretch.Changes in the bacteria...A typical anthropogenically disturbed urban river polluted by a combination of conventional pollutants(nitrogen and phosphorus pollution)and heavy metals was investigated along a 238 km stretch.Changes in the bacterial community were evaluated using high-throughput sequencing,and the relationships between bacteria,heavy metals,and conventional pollutants were investigated.There was large spatial heterogeneity in the bacterial community along the river,and bacterial diversity in the upstream and midstream sections was much higher than in the downstream section.Heavy metals and conventional pollutants both exhibited close correlations with bacterial diversity and composition.For instance,potential fecal indicator bacteria,sewage indicator bacteria and pathogenic bacteria,such as Ruminococcus and Pseudomonas,were closely associated with Cu,Zn,and NH_(4)^(+)-N.Rather than conventional pollutants,heavy metals were the main driving factors of the microbial community characteristics.These results confirm that bacterial communities play a crucial role in biogeochemical cycles.Therefore,heavymetals could be used as biomarkers of complex pollution to indicate the pollution status of riverine ecosystems and contribute to the restoration of habitats in anthropogenically disturbed urban rivers.展开更多
This paper investigates a time-varying anti-disturbance formation problem for a group of quadrotor aircrafts with time-varying uncertainties and a directed interaction topology.A novel Finite-Time Convergent Extended ...This paper investigates a time-varying anti-disturbance formation problem for a group of quadrotor aircrafts with time-varying uncertainties and a directed interaction topology.A novel Finite-Time Convergent Extended State Observer(FTCESO)based fully-distributed formation control scheme is proposed to enhance the disturbance rejection and the formation tracking performances for networked quadrotors.By adopting the hierarchical control strategy,the multiquadrotor system is separated into two subsystems:the outer-loop cooperative subsystem and the inner-loop attitude subsystem.In the outer-loop subsystem,with the estimation of disturbing forces and uncertain dynamics from FTCESOs,an adaptive consensus theory based cooperative controller is exploited to ensure the multiple quadrotors form and maintain a time-varying pattern relying only on the positions of the neighboring aircrafts.In the inner-loop subsystem,the desired attitude generated by the cooperative control law is stably tracked under a FTCESO-based attitude controller in a finite time.Based on a detailed algorithm to specify the cooperative control protocol,the feasibility condition to achieve the time-varying anti-disturbance formation tracking is derived and the rigorous analysis of the whole closed-loop multi-quadrotor system is given.Some numerical examples are conducted to intuitively demonstrate the effectiveness and the improvements of the proposed control framework.展开更多
基金The authors acknowledge the financial support of China University of Mining&Technology(Beijing),Beijing National Laboratory for Condensed Matter Physicsthe National Natural Science Founda-tion of China(Nos.51672029 and 51372271).
文摘Solid-state batteries have been considered as a good choice for substituting traditional batteries with liquid electrolytes because of their high energy density and safe property.However,a little amount of flammable non-aqueous liquid electrolyte or polymer electrolyte is usually required to improve the interfacial contact,which is adverse to safety.Here,a nonflammable gel is prepared by hydrogen-bond interaction and applied as an interfacial layer to improve the performance of solid-state batteries.The prepared multilayer hybrid electrolyte(MHE)composed of gel and CPE shows a wide electrochemical window(5.3 V vs Li/Li+),high ionic transference number(0.57),and ionic conductivity(7.18×10^(−4) S cm^(−1))at room temperature.Thus,the assembled Li symmetric cell with MHE can cycle over 650 h at 0.5 mA cm^(−2) with a lower overpotential of~61 mV.The LiFePO_(4)|MHE|Li cell exhibits a higher discharge capacity of 107.8 mAh g−1 even cycled at 5 C.It also shows superior capacity retention of 96.4%after 1000 cycles at 0.5 C.This work provides a promising strategy for designing high-performance solid-state batteries.
文摘Beyond regulation of male sexual function, the increasing evidence shows that androgens and androgen receptor (AR) have a variety of physiological and pathological effects on the skin. Skin cells express all androgen metabolizing enzymes that are required for independent skin androgen synthesis and the development of hyperandrogenic related disorders such as acne, hirsutism and androgenetic alopecia. Targeting various elements of androgen function and metabolism is the major goal of medication design for the treatment of androgen-related diseases. Antiandrogen drugs such as clascoterone, flutamide could improve conditions. Even though the involvement of androgens and AR in skin diseases has been investigated for a long time, their molecular mechanisms in skin disorders remain largely insufficient. In this review, recent studies and advances on the role of androgens/AR in several skin-related diseases and their therapeutics are systematically summarized.
基金AcknowledgementsThis work is financially supported by the National Natural Science Foundation of China （61005015）, the third National Post-Doctoral Special Foundation of China （201003280）, and 2011 Shanshai city young teachers＇ subsidy scheme. The authors would like to thank the reviewers for their useful comments.
文摘This paper presents a new fall detection method of etderly people in a room environment based on shape analysis of 3D depth images captured by a Kinect sensor. Depth images are pre- processed by a median filter both for background and target. The sithouette of moving individual in depth images is achieved by a subtraction method for background frames. The depth images are converted to disparity map, which is obtained by the horizontal and vertical projection histogram statistics. The initial floor plane information is obtained by V disparity map, and the floor ptane equation is estimated by the least square method. Shape information of human subject in depth images is analyzed by a set of moment functions. Coefficients of ellipses are calculated to determine the direction of individual The centroids of the human body are catculated and the angle between the human body and the floor plane is calculated. When both the distance from the centroids of the human body to the floor plane and the angle between the human body and the floor plane are tower than some threshotds, fall incident will be detected. Experiments with different failing direction are performed. Experimental results show that the proposed method can detect fall incidents effectively.
基金the financial support from Shenzhen Science and Technology Innovation Committee under the Grant Nos. JCYJ20170818103206501, Type C 202011033000145Changsha Municipal Science and Technology Bureau Project kh2201035supported by the City University of Hong Kong under the Grant No. 9667226
文摘Projection micro stereolithography(PμSL)has emerged as a powerful three-dimensional(3D)printing technique for manufacturing polymer structures with micron-scale high resolution at high printing speed,which enables the production of customized 3D microlattices with feature sizes down to several microns.However,the mechanical properties of as-printed polymers were not systemically studied at the relevant length scales,especially when the feature sizes step into micron/sub-micron level,limiting its reliable performance prediction in micro/nanolattice and other metamaterial applications.In this work,we demonstrate that PμSL-printed microfibers could become stronger and significantly more ductile with reduced size ranging from 20μm to 60μm,showing an obvious size-dependent mechanical behavior,in which the size decreases to 20μm with a fracture strain up to~100%and fracture strength up to~100 MPa.Such size effect enables the tailoring of the material strength and stiffness of PμSL-printed microlattices over a broad range,allowing to fabricate the microlattice metamaterials with desired/tunable mechanical properties for various structural and functional applications.
基金China Ocean Mineral Resources Research and Development under contract No.DY125-11-R-04the National Natural Science Foundation of China under contract No.41676036
文摘The carbonate-free fraction of 20 surface sediments collected from the ultraslow-spreading Southwest Indian Ridge(SWIR) was studied by grain size analysis and mineralogical analysis with X-ray powder diffraction(XRD),stereo microscopy and scanning electron microscopy(SEM). The characteristics of the carbonate-free fraction of the sediments were obtained, and related influential factors were discussed. The results show that the mean grain size of this fraction is in 1.96Φ–8.19Φ, with poorly sorting and unimodal, bimodal or irregular bimodal distribution patterns. Four grain size end members of the fraction are derived with the End Member Model method. The finest end member EM1 shows a significant contribution of terrigenous materials of the aeolian input and sediment carried by the bottom current. End member EM2 with medium size mainly reflects sediment of a siliceous bioclast origin. EM3 and EM4 are interpreted as representing the coarser volcanic materials related to bedrock weathering or volcanic activities. Multi-provenance is the dominant factor controlling the grain size pattern of the carbonate-free fraction of the sediments in that area. In addition, sediment transport processes such as the bottom current and wind are the minor factors that influence the grain size distribution of the carbonate-free fraction sediments.
基金the Natural Key Research and Development Program of China(Grant No.2017YFC0405103).
文摘Numerical simulation is known as an effective method for mechanical properties during frozen soil excavation.In order to reveal the development of cutting force,effective stress and cutting fragments in frozen silt during the cutting process,we introduce an explicit finite element program LS-DYNA to establish a two-dimensional numerical model of the frozen soil cut.We also use the Holmquist-Johnson-Cook(HJC)damage constitutive model for simulating the variation of soil mechanical properties according to the strong dependence between the cutting tool and frozen silt during the process with different cutting depths,angles and velocities.Meanwhile,a series of experimental results are acquired of frozen silt cutting to prove the application of the HJC model during simulation of cutting force variations.The result shows that the cutting force and fragment size are strongly influenced by cutting depths and cutting velocities increased,and the maximum effective stress at points where the tool contacts frozen soil during the cutting process.In addition,when the cutting angle is 52°,the cutting force is the smallest,and the cutting angle is optimum.Thus,the prediction of frozen soil mechanical properties on the cutting process by this model is conducive to selecting machinery equipment in the field.
基金This work was supported in part by the National Natural Science Foundation of China (No. 61170094), Shanghai Committee of Science and Technology (14JC1402202 and 14441904403), and 863 Program 2014AA015101.
文摘With the high-speed development of digital image processing technology, machine vision technology has been widely used in automatic detection of industrial products. A large amount of products can be treated by computer instead of human in a shorter time. In the process of automatic detection, edge detection is one of the most commonly used methods. But with the increasing demand for detection precision,traditional pixel-level methods are difficult to meet the requirement, and more subpixel level methods are in the use. This paper presents a new method to detect curved edge with high precision. First, the target area ratio of pixels near the edge is computed by using one-dimensional edge detection method. Second, parabola is used to approximately represent the curved edge. And we select appropriate parameters to obtain accurate results. This method is able to detect curved edges in subpixel level, and shows its practical effectiveness in automatic measure of products with arc shape in large industrial scene.
基金supported by the National Key R&D Program of China(Nos.2022YFC3600600,2022YFC3600604)the National Natural Science Foundation of China(Nos.U22A20359,81874283,and 81673255)+2 种基金the Recruitment Program for Young Professionals of Chinathe Promotion Plan for Basic Medical Sciencesthe Development Plan for Cutting-Edge Disciplines,Sichuan University.
文摘Background:While type 2 diabetes mellitus(T2DM)is considered a putative causal risk factor for coronary artery disease(CAD),the intrinsic link underlying T2DM and CAD is not fully understood.We aimed to highlight the importance of integrated care targeting both diseases by investigating the phenotypic and genetic relationships between T2DM and CAD.Methods:We evaluated phenotypic associations using data from the United Kingdom Biobank(N=472,050).We investigated genetic relationships by leveraging genomic data conducted in European ancestry for T2DM,with and without adjustment for body mass index(BMI)(T2DM:N_(case)/N_(control)=74,124/824,006;T2DM adjusted for BMI[T2DM_(adj)BMI]:N_(case)/N_(control)=50,409/523,897)and for CAD(N_(case)/N_(control)=181,522/984,168).We performed additional analyses using genomic data conducted in multiancestry individuals for T2DM(N_(case)/N_(control)=180,834/1,159,055).Results:Observational analysis suggested a bidirectional relationship between T2DM and CAD(T2DM→CAD:hazard ratio[HR]=2.12,95%confidence interval[CI]:2.01–2.24;CAD→T2DM:HR=1.72,95%CI:1.63–1.81).A positive overall genetic correlation between T2DM and CAD was observed(r_(g)=0.39,P=1.43×10^(-75)),which was largely independent of BMI(T2DM_(adj)BMI–CAD:r_(g)=0.31,P=1.20×10^(–36)).This was corroborated by six local signals,among which 9p21.3 showed the strongest genetic correlation.Cross-trait meta-analysis replicated 101 previously reported loci and discovered six novel pleiotropic loci.Mendelian randomization analysis supported a bidirectional causal relationship(T2DM→CAD:odds ratio[OR]=1.13,95%CI:1.11-1.16;CAD→T2DM:OR=1.12,95%CI:1.07-1.18),which was confirmed in multiancestry individuals(T2DM→CAD:OR=1.13,95%CI:1.10-1.16;CAD→T2DM:OR=1.08,95%CI:1.04-1.13).This bidirectional relationship was significantly mediated by systolic blood pressure and intake of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors,with mediation proportions of 54.1%(95%CI:24.9-83.4%)and 90.4%(95%CI:29.3-151.5%),respectively.Conclusion:Our observational and genetic analyses demonstrated an intrinsic bidirectional relationship between T2DM and CAD and clarified the biological mechanisms underlying this relationship.
基金the National Science and Technology Major Project,China(Nos.J2019-Ⅱ-0020-0041 and J2019-Ⅱ-0017-0038)the Science Center for Gas Turbine Project,China(No.P2022-A-Ⅱ-002-001)the National Natural Science Foundation of China(No.52206061).
文摘To numerically study the impact of total temperature distortion on a transonic compressor with reduced computational costs,a Body-Force Model(BFM)is developed.Firstly,the interactions between the distorted flow and the compressor are analyzed using full-annulus Unsteady Reynolds-Averaged Navier-Stokes(URANS)results and the orbit method.It is found that the induced swirl distortion and the mass flux nonuniformity are intensified in the compressor upstream flow field.A correction factor is thus added to the BFM to account for the effect of the induced swirl,which is crucial for the accurate representation of distortion transfer in the intake.Then,steady simulations with large-amplitude 180circumferential total temperature distortion are performed using the developed BFM.It is shown that the distorted compressor map simulated with the BFM matches well with URANS results.The circumferential phase shift of total temperature and the generation of the additional total pressure distortion across the rotor are in line with the time-averaged URANS flow field.The compressor upstream effects on the distorted inflow can also be exactly captured.All above-mentioned results demonstrate the BFM developed in this paper can effectively capture the distorted flow features inside the compressor,and significantly reduce the computational costs by five orders of magnitude compared with URANS.
基金the National Natural Science Foundation of China(82302395,82102348,82001979,82372390 and 31900963)the Natural Science Foundation of Shanghai(22YF1437400)+3 种基金Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)the Health-Education Joint Research Project of Fujian Province(2019-WJ-22)Taishan Scholar Program of Shandong Province(tsqn20230633)ShanghiaHi ealth Promotion Commission,Shanghai 2023 Health Science Popularization Special Plan‘Prevention and Control Science Popularization System for Hip Fall Injury in the Elderly'(JKKPZX-2023-A27)and the Fundamental Research Funds for the Central Universities(2021CDJQY-017).
文摘Acellular dermal matrix(ADM)shows promise for cartilage regeneration and repair.However,an effective decellularization technique that removes cellular components while preserving the extracellular matrix,the transformation of 2D-ADM into a suitable 3D scaffold with porosity and the enhancement of bioactive and biomechanical properties in the 3D-ADM scaffold are yet to be fully addressed.In this study,we present an innovative decellularization method involving 0.125%trypsin and 0.5%SDS and a 1%Triton X-100 solution for preparing ADM and converting 2D-ADM into 3D-ADM scaffolds.These scaffolds exhibit favorable physicochemical properties,exceptional biocompatibility and significant potential for driving cartilage regeneration in vitro and in vivo.To further enhance the cartilage regeneration potential of 3D-ADM scaffolds.we incorporated porcine-derived small intestinal submucosa(SIS)for bioactivity and calcium sulfate hemihydrate(CSH)for biomechanical reinforcement.The resulting 3D-ADM+SIS scaffolds displayed heightened biological activity,while the 3D-ADM+CSH scaffolds notably bolstered biomechanical strength.Both scaffold types showed promise for cartilage regeneration and repair in vitro and in vivo,with considerable improvements observed in repairing cartilage defects within a rabbit articular cartilage model.In summary,this research introduces a versatile 3D-ADM scaffold with customizable bioactive and biomechanical properties,poised to revolutionize the field of cartilageregeneration.
文摘The Haber-Bosch process is the most widely used synthetic ammonia technology at present.Since its invention,it has provided an important guarantee for global food security.However,the traditional Haber-Bosch ammonia synthesis process consumes a lot of energy and causes serious environmental pollution.Under the serious pressure of energy and environment,a green,clean,and sustainable ammonia synthesis route is urgently needed.Electrochemical synthesis of ammonia is a green and mild new method for preparing ammonia,which can directly convert nitrogen or nitrate into ammonia using electricity driven by solar,wind,or water energy,without greenhouse gas and toxic gas emissions.Herein,the basic mechanism of the nitrogen reduction reaction(NRR)to ammonia and nitrate reduction reaction(NO_(3)^(-))to ammonia were discussed.The representative approaches and major technologies,such as lithium mediated electrolysis and solid oxide electrolysis cell(SOEC)electrolysis for NRR,high activity catalyst and advanced electrochemical device fabrication for(NO_(3)^(-))RR and electrochemical ammonia synthesis were summarized.Based on the above discussion and analysis,the main challenges and development directions for electrochemical ammonia synthesis were further proposed.
文摘Interconnector is a critical component to construct solid oxide cells (SOCs) stack. Oxidation of metallic interconnectors and Cr poisoning caused by oxidation are important factors that lead to long-term performance degradation of SOCs. Coating on the interconnector surface is an important approach to inhibit the oxidation and Cr migration of the interconnector. Herein, (La0.75Sr0.25)0.95MnO3–δ (LSM) and Mn1.5Co1.5O4 (MCO) are used to fabricate the coatings of interconnector. Two advanced thermal spray technology, atmospheric plasma spraying (APS) and low-pressure plasma spray (LPPS), are adopted for the coating preparation. The electrochemical performance, rising and cooling cycle stability, and Cr diffusion inhibition performance of the coatings are tested and evaluated. The result indicates that MCO can generate more uniform and denser coatings than LSM. In addition, MCO coatings prepared by LPPS shows the best electrochemical performance, rising and cooling cycle stability, and Cr diffusion inhibition. The initial area specific resistance (ASR) is 0.0027 Ω·cm2 at 800 °C. After 4 cooling cycle tests, the ASR increases to 0.0032 Ω·cm2 but lower than other samples. Meanwhile, the relative intense of Cr at the interface of SUS430 with MCO coatings fabricated by LPPS is lower than that of MCO fabricated by APS after 4 rising and cooling cycle operations, showing more favorable Cr diffusion inhibition performance.
基金supported by the National Natural Science Foundation of China(T2121003,No.52022008,51975030)partially supported by the Bejing Municipal Natural Science Foundation(M22021).
文摘Polyimides are widely used in the MEMS and flexible electronics fields due to their combined physicochemical properties,including high thermal stability,mechanical strength,and chemical resistance values.In the past decade,rapid progress has been made in the microfabrication of polyimides.However,enabling technologies,such as laser-induced graphene on polyimide,photosensitive polyimide micropatterning,and 3D polyimide microstructure assembly,have not been reviewed from the perspective of polyimide microfabrication.The aims of this review are to systematically discuss polyimide microfabrication techniques,which cover flm formation,material conversion,micropatterning,3D microfabrication,and their applications.With an emphasis on polyimide-based flexible MEMS devices,we discuss the remaining technological challenges in polyimide fabrication and possible technological innovations in this field.
基金co-supported by the National Natural Science Foundation of China(No.51922098)the National Science and Technology Major Project of China(No.2017-Ⅱ-0004-0017)the Special Fund for the Member of Youth Innovation Promotion Association of CAS(No.2018173).
文摘The adaptive feedback control of stability with circumferential inlet distortion has been experimentally investigated in a low-speed,axial compressor.The flat-baffles with different span heights are used to simulate different distorted inflow cases.Compared with auto-correlation and root-mean-square analysis,cross-correlation analysis used to predict early stall warning does not depend on the distortion position.Hence,the cross-correlation coefficient was used to monitor the stable status of the compressor and provide the feedback signal in the active control strategy when suffering from different distortions.Based on the stall margin improvement of tip air injection obtained under different distorted inflow cases and the sensitivity analysis of cross-correlation coefficients to injected momentum ratios,tip air injection was adopted as the actuator for adaptive feedback control.The digital signal processing controller was designed and applied to achieve adaptive feedback control in distorted inflow conditions.The results show that the adaptive feedback control of air injection nearly achieves the same stall margin improvement as steady air injection under different distortion intensities with a reduced injection mass flow.Thus,the proposed adaptive feedback control method is ideal for the engine operation with circumferential distorted inflow,which frequently occurs in flight.
基金This work was financially supported by the National Natural Science Foundation of China(grant nos.21620102001,91856204,91956124,and 21875136)Key Project of Basic Research of Shanghai(grant no.19JC1412600)Shanghai Rising-Star Program(grant no.19QA1404300),and the China Postdoctoral Science Foundation(grant no.2020M681280).
文摘Self-assembly has been widely explored to improve the circularly polarized_(lum)inescence(CPL)activities of molecular chromophores,but it is hard to amplify CPL while maintaining strong emissions.Optically pure,planar-chiral[2.2]paracyclophane(pCp)is one of the most important sources of chirality for electronic and optoelectronic materials,but the photo_(lum)inescence of its derivatives is significantly quenched after forming aggregates.Here we demonstrate that reticulation of pCp chromophores into highly stable Zr(IV)metal-organic frameworks(MOFs)can simultaneously boost the dissymmetry factor(|g_(lum)|)and_(lum)inescence efficiency(Φ_(PL)).Functionalization of pCp enables the synthesis of two tetracarboxylate linkers with different side arms,which are assembled into two highly stable Zr-MOFswith different topological structures.Geometrical constraints and segregated arrangements of the pCp chromophores imposed by the framework inhibit the aggregation-caused quenching effect and boost their CPL behaviors.Both Zr-MOFs display strong CPL emissions,affording|g_(lum)|andΦ_(PL)values of up to 8.3×10^(-3)and 87%,respectively,which are amplified by∼18-and 52-fold compared to the corresponding free ligands.This work highlights the potential of optimizing CPL performances of chiral chromophores by using MOFs as support structures.
基金supported by the Youth Innovation Promotion Association CAS(Wenqiang Zhang,No.2018058)the Key-Area Research and Development Program of Guangdong Province(No.2019B110205002).
文摘Degradation of organic matter(OM)in sediments is a key link in nutrient cycling and sedimentation processes in lakes.The aim of this study was to explore the degradation of OM in surface sediments of a shallow lake(Baiyangdian Lake,China)under seasonal temperature variations.For this,we used the amino acid-based degradation index(DI)and the spatiotemporal distribution characteristics and sources of OM.Sediment OM in the lake mainly originated from freshwater aquatic plants and terrestrial C4 plants.The sediment at some sampling sites was affected by surrounding crops.The organic carbon and total nitrogen contents,and the total hydrolyzed amino acid concentrations in the sediments were highest in summer and lowest in winter.The lowest DI occurred in spring,which indicated that the OM in the surface sediment at this time was highly degraded and relatively stable,and the highest DI occurred in winter,which showed that the sediment was fresh.The water temperature was positively correlated with the organic carbon content(p<0.01)and total hydrolyzed amino acids concentration(p<0.05).Seasonal variations in the overlying water temperature had a large effect on OM degradation in the lake sediments.Our results will facilitate the management and restoration of lake sediments that suffer from endogenous release of OM in a warming climate。
基金supported by the Key-Area Research and Development Program of Guangdong Province(No.2019B110205002)the Youth Innovation Promotion Association CAS from the Chinese Academy of Sciences(No.2018058)the National Major Science and Technology Program for Water Pollution Control and Treatment(No.2017ZX07107-004).
文摘A typical anthropogenically disturbed urban river polluted by a combination of conventional pollutants(nitrogen and phosphorus pollution)and heavy metals was investigated along a 238 km stretch.Changes in the bacterial community were evaluated using high-throughput sequencing,and the relationships between bacteria,heavy metals,and conventional pollutants were investigated.There was large spatial heterogeneity in the bacterial community along the river,and bacterial diversity in the upstream and midstream sections was much higher than in the downstream section.Heavy metals and conventional pollutants both exhibited close correlations with bacterial diversity and composition.For instance,potential fecal indicator bacteria,sewage indicator bacteria and pathogenic bacteria,such as Ruminococcus and Pseudomonas,were closely associated with Cu,Zn,and NH_(4)^(+)-N.Rather than conventional pollutants,heavy metals were the main driving factors of the microbial community characteristics.These results confirm that bacterial communities play a crucial role in biogeochemical cycles.Therefore,heavymetals could be used as biomarkers of complex pollution to indicate the pollution status of riverine ecosystems and contribute to the restoration of habitats in anthropogenically disturbed urban rivers.
文摘This paper investigates a time-varying anti-disturbance formation problem for a group of quadrotor aircrafts with time-varying uncertainties and a directed interaction topology.A novel Finite-Time Convergent Extended State Observer(FTCESO)based fully-distributed formation control scheme is proposed to enhance the disturbance rejection and the formation tracking performances for networked quadrotors.By adopting the hierarchical control strategy,the multiquadrotor system is separated into two subsystems:the outer-loop cooperative subsystem and the inner-loop attitude subsystem.In the outer-loop subsystem,with the estimation of disturbing forces and uncertain dynamics from FTCESOs,an adaptive consensus theory based cooperative controller is exploited to ensure the multiple quadrotors form and maintain a time-varying pattern relying only on the positions of the neighboring aircrafts.In the inner-loop subsystem,the desired attitude generated by the cooperative control law is stably tracked under a FTCESO-based attitude controller in a finite time.Based on a detailed algorithm to specify the cooperative control protocol,the feasibility condition to achieve the time-varying anti-disturbance formation tracking is derived and the rigorous analysis of the whole closed-loop multi-quadrotor system is given.Some numerical examples are conducted to intuitively demonstrate the effectiveness and the improvements of the proposed control framework.
