Low-temperature processed electron transport layer(ETL)of TiO_(2)that is widely used in planar perovskite solar cells(PSCs)has inherent low carrier mobility,resulting in insufficient photogenerated elec-tron transport...Low-temperature processed electron transport layer(ETL)of TiO_(2)that is widely used in planar perovskite solar cells(PSCs)has inherent low carrier mobility,resulting in insufficient photogenerated elec-tron transport and thus recombination loss at buried interface.Herein,we demonstrate an effective strategy of laser embedding of p-n homojunctions in the TiO_(2)ETL to accelerate electron transport in PSCs,through localized build-in electric fields that enables boosted electron mobility by two orders of magnitude.Such embedding is found significantly helpful for not only the enhanced crystallization quality of TiO_(2)ETL,but the fabrication of perovskite films with larger-grain and the less-trap-states.The embedded p-n homojunction enables also the modulation of interfacial energy level between perovskite layers and ETLs,favoring for the reduced voltage deficit of PSCs.Benefiting from these merits,the formamidinium lead iodide(FAPbI_(3))PSCs employing such ETLs deliver a champion efficiency of 25.50%,along with much-improved device stability under harsh conditions,i.e.,maintain over 95%of their initial efficiency after operation at maximum power point under continuous heat and illumination for 500 h,as well as mixed-cation PSCs with a champion efficiency of 22.02%and over 3000 h of ambient storage under humidity stability of 40%.Present study offers new possibilities of regulating charge transport layers via p-n homojunction embedding for high performance optoelectronics.展开更多
Exploiting high-performance yet low-cost hard carbon anodes is crucial to advancing the state-of-the-art sodium-ion batteries.However,the achievement of superior initial Coulombic efficiency(ICE)and high Na-storage ca...Exploiting high-performance yet low-cost hard carbon anodes is crucial to advancing the state-of-the-art sodium-ion batteries.However,the achievement of superior initial Coulombic efficiency(ICE)and high Na-storage capacity via low-temperature carbonization remains challenging due to the presence of tremendous defects with few closed pores.Here,a facile hybrid carbon framework design is proposed from the polystyrene precursor bearing distinct molecular bridges at a low pyrolysis temperature of 800℃ via in situ fusion and embedding strategy.This is realized by integrating triazine-and carbonylcrosslinked polystyrene nanospheres during carbonization.The triazine crosslinking allows in situ fusion of spheres into layered carbon with low defects and abundant closed pores,which serves as a matrix for embedding the well-retained carbon spheres with nanopores/defects derived from carbonyl crosslinking.Therefore,the hybrid hard carbon with intimate interface showcases synergistic Na ions storage behavior,showing an ICE of 70.2%,a high capacity of 279.3 mAh g^(-1),and long-term 500 cycles,superior to carbons from the respective precursor and other reported carbons fabricated under the low carbonization temperature.The present protocol opens new avenues toward low-cost hard carbon anode materials for high-performance sodiumion batteries.展开更多
In clinical practice,the microscopic examination of urine sediment is considered an important in vitro examination with many broad applications.Measuring the amount of each type of urine sediment allows for screening,...In clinical practice,the microscopic examination of urine sediment is considered an important in vitro examination with many broad applications.Measuring the amount of each type of urine sediment allows for screening,diagnosis and evaluation of kidney and urinary tract disease,providing insight into the specific type and severity.However,manual urine sediment examination is labor-intensive,time-consuming,and subjective.Traditional machine learning based object detection methods require hand-crafted features for localization and classification,which have poor generalization capabilities and are difficult to quickly and accurately detect the number of urine sediments.Deep learning based object detection methods have the potential to address the challenges mentioned above,but these methods require access to large urine sediment image datasets.Unfortunately,only a limited number of publicly available urine sediment datasets are currently available.To alleviate the lack of urine sediment datasets in medical image analysis,we propose a new dataset named UriSed2K,which contains 2465 high-quality images annotated with expert guidance.Two main challenges are associated with our dataset:a large number of small objects and the occlusion between these small objects.Our manuscript focuses on applying deep learning object detection methods to the urine sediment dataset and addressing the challenges presented by this dataset.Specifically,our goal is to improve the accuracy and efficiency of the detection algorithm and,in doing so,provide medical professionals with an automatic detector that saves time and effort.We propose an improved lightweight one-stage object detection algorithm called Discriminatory-YOLO.The proposed algorithm comprises a local context attention module and a global background suppression module,which aid the detector in distinguishing urine sediment features in the image.The local context attention module captures context information beyond the object region,while the global background suppression module emphasizes objects in uninformative backgrounds.We comprehensively evaluate our method on the UriSed2K dataset,which includes seven categories of urine sediments,such as erythrocytes(red blood cells),leukocytes(white blood cells),epithelial cells,crystals,mycetes,broken erythrocytes,and broken leukocytes,achieving the best average precision(AP)of 95.3%while taking only 10 ms per image.The source code and dataset are available at https://github.com/binghuiwu98/discriminatoryyolov5.展开更多
Composite solid electrolytes(CSEs)with poly(ethylene oxide)(PEO)have become fairly prevalent for fabricating high-performance solid-state lithium metal batteries due to their high Li~+solvating capability,flexible pro...Composite solid electrolytes(CSEs)with poly(ethylene oxide)(PEO)have become fairly prevalent for fabricating high-performance solid-state lithium metal batteries due to their high Li~+solvating capability,flexible processability and low cost.However,unsatisfactory room-temperature ionic conductivity,weak interfacial compatibility and uncontrollable Li dendrite growth seriously hinder their progress.Enormous efforts have been devoted to combining PEO with ceramics either as fillers or major matrix with the rational design of two-phase architecture,spatial distribution and content,which is anticipated to hold the key to increasing ionic conductivity and resolving interfacial compatibility within CSEs and between CSEs/electrodes.Unfortunately,a comprehensive review exclusively discussing the design,preparation and application of PEO/ceramic-based CSEs is largely lacking,in spite of tremendous reviews dealing with a broad spectrum of polymers and ceramics.Consequently,this review targets recent advances in PEO/ceramicbased CSEs,starting with a brief introduction,followed by their ionic conduction mechanism,preparation methods,and then an emphasis on resolving ionic conductivity and interfacial compatibility.Afterward,their applications in solid-state lithium metal batteries with transition metal oxides and sulfur cathodes are summarized.Finally,a summary and outlook on existing challenges and future research directions are proposed.展开更多
Fluoride ferrous(FeF_(2))is viewed as a promising conversion cathode material for next-generation lithiumion batteries(LIBs)due to its high theoretical specific capacity and low cost.Unfortunately,issues such as poor ...Fluoride ferrous(FeF_(2))is viewed as a promising conversion cathode material for next-generation lithiumion batteries(LIBs)due to its high theoretical specific capacity and low cost.Unfortunately,issues such as poor intrinsic conductivity,iron dissolution,and phase separation hinder the application of FeF_(2)in highenergy cathodes.Here,a pressure-induced morphology control method is designed to prepare coralloidlike FeF_(2)nanocrystals with nitrogen-rich carbon coating(c-FeF_(2)@NC).The coralloid-like interconnected crystal structure of c-FeF_(2)@NC contributes to reducing interfacial resistance and enhancing the topotactic transformation during the conversion reaction,and the nitrogen-rich carbon(NC)coating can enhance interfacial stability and kinetic performance.When used as a conversion cathode for LIBs,c-FeF_(2)@NC exhibits a high initial reversible capacity of 503.57 mA h g^(-1)and excellent cycling stability of497.61 m A h g^(-1)with a low capacity decay of 1.19%over 50 cycles at 0.1 A/g.Even at 1 A/g,a stable capacity of 263.78 mA h g^(-1)can still be retained after 200 cycles.The capability of c-FeF_(2)@NC as a conversion cathode for sodium-ion batteries(SIBs)was also evaluated to expand its field of application.Furthermore,two kinds of full batteries have been assembled by employing c-FeF_(2)@NC as cathodes and quantitative limited-Li(LLi)and pre-lithiated reduced graphene oxide(PGO)as anodes,respectively,to envisage the feasibility of practical applications of conversion materials.展开更多
Charging P2-Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)to 4.5 V for higher capacity is enticing.However,it leads to severe capacity fading,ascribing to the lattice oxygen evolution and the P2-O2 phase transformation.Here,the Mg Fe_...Charging P2-Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)to 4.5 V for higher capacity is enticing.However,it leads to severe capacity fading,ascribing to the lattice oxygen evolution and the P2-O2 phase transformation.Here,the Mg Fe_(2)O_(4) coating and Mg,Fe co-doping were constructed simultaneously by Mg,Fe surface treatment to suppress lattice oxygen evolution and P2-O2 phase transformation of P2-Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)at deep charging.Through ex-situ X-ray diffraction(XRD)tests,we found that the Mg,Fe bulk co-doping could reduce the repulsion between transition metals and Na+/vacancies ordering,thus inhibiting the P2-O2 phase transition and significantly reducing the irreversible volume change of the material.Meanwhile,the internal electric field formed by the dielectric polarization of Mg Fe_(2)O_(4) effectively inhibits the outward migration of oxidized O^(a-)(a<2),thereby suppressing the lattice oxygen evolution at deep charging,confirmed by in situ Raman and ex situ XPS techniques.P2-Na NM@MF-3 shows enhanced high-voltage cycling performance with capacity retentions of 84.8% and 81.3%at 0.1 and 1 C after cycles.This work sheds light on regulating the surface chemistry for Na-layered oxide materials to enhance the high-voltage performance of Na-ion batteries.展开更多
Onedimensional porous carbons bearing high surface areas and sufficient heteroatom doped functionalities are essential for advanced electrochemical energy storage devices,especially for developing freestanding film el...Onedimensional porous carbons bearing high surface areas and sufficient heteroatom doped functionalities are essential for advanced electrochemical energy storage devices,especially for developing freestanding film electrodes.Here we develop a porous,nitrogenenriched,freestanding hollow carbon nanofiber(PNFHCF)electrode material via filtration of polypyrrole(PPy)hollow nanofibers formed by in situ selfdegraded templateassisted strategy,followed by NH3assisted carbonization.The PNFHCF retains the freestanding film morphology that is composed of threedimensional networks from the entanglement of 1D nanofiber and delivers 3.7fold increase in specific surface area(592 m^(2)g^(-1))compared to the carbon without NH_(3)treatment(FHCF).In spite of the enhanced specific surface area,PNFHCF still exhibits comparable high content of surface N functionalities(8.8%,atom fraction)to FHCF.Such developed hierarchical porous structure without sacrificing N doping functionalities together enables the achievement of high capacity,highrate property and good cycling stability when applied as selfsupporting anode in lithiumion batteries,superior to those of FHCF without NH3 treatment.展开更多
This worked aimed to test the hypothesis that L-alanyl-L-glutamine(Ala-Gln)improves the varicocele-induced testicular injury,which causes male infertility.For this purpose,fifty adult male Wistar rats received the var...This worked aimed to test the hypothesis that L-alanyl-L-glutamine(Ala-Gln)improves the varicocele-induced testicular injury,which causes male infertility.For this purpose,fifty adult male Wistar rats received the varicocele(VC)surgery at the left renal vein.Biomarkers were determined 2,4,and 8 weeks after VC(n=10/each detection).Four weeks after VC,rats received Ala-Gln(1.125 g/kg)treatment with and or saline for 1 week(n=10/each group).Rats in the sham group were also detected for biomarkers at 2,4,and 8 weeks(n=10/each detection).VC caused testicular injury detected by hematoxylin–eosin(H&E)staining,immunohistochemistry,and TUNEL assay.HSP70 mRNA was detected quantitative RT-PCR,SOD,and CAT by nitroblue tetrazolium(NBT)method and 8-OHDG by ELISA.The results showed that varicocele induced injury in the testes.The weight of the left testes was lower than that of the right testes in VC-bearing rats(p<0.01).The relative numbers of sustentacular and spermatogenic cells were decreased after VC(p<0.01).In sham-4 wk,VC-4wk,VC-5wk and Ala-Gln groups,the apoptosis index was 5.10±1.14,13.22±3.63,33.62±3.56 and 22.33±2.61,relative level of HSP70 mRNA 1.00±0.12,0.53±0.05,0.51±0.04 and 1.62±0.15 fold,SOD 16.4±0.23,13.4±0.17,10.01±1.06 and 19.53±2.26 U/mg protein,CAT 2.16±0.31,1.07±0.28,and 1.31±0.26 and 3.46±0.71 U/mg,8-OHDG 5.23±0.67,6.81±0.78,7.16±1.22 and 4.14±0.73 pg/μg DNA,respectively(p<0.01).Our results suggest that Ala-Gln prevented the VC-induced testicular injury.We have firstly reported that Ala-Gln protects against varicocele-induced testicular injuries by up-regulation of HSP70 and antioxidants,SOD and CAT,and down-regulation of oxidant 8-OHDG,resulting in reducing apoptosis in the testis.展开更多
The sluggish redox kinetics and shuttle effect of soluble polysulfides intermediate primarily restrict the electrochemical performance of lithium–sulfur(Li–S) batteries. To address this issue, rational design of hig...The sluggish redox kinetics and shuttle effect of soluble polysulfides intermediate primarily restrict the electrochemical performance of lithium–sulfur(Li–S) batteries. To address this issue, rational design of high–efficiency sulfur host is increasingly demanded to accelerate the polysulfides conversion during charge/discharge process. Herein, we propose a macro–mesoporous sulfur host(Co@NC), which comprises highly dispersed cobalt nanoparticles embedding in N–doped ultrathin carbon nanosheets. Co@NC is simply synthesized via a carbon nitride–derived pyrolysis approach. Owing to the highly conductive graphene–like matrix and well defined porous structure, the designed multifunctional Co@NC host enables rapid electron/ion transport, electrolyte penetration and effective sulfur trapping. More significantly,N heteroatoms and homogeneous Co nanocatalysts in the graphitic carbon nanosheets could serve as chemisorption sites as well as electrocatalytic centers for sulfur species. These Co–N active sites can synergistically facilitate the redox conversion kinetics and mitigate the shuttling of polysulfides, thus leading to improved electrochemical cycling performance of Li–S batteries. As a consequence, the S/Co@NC cathode demonstrates high initial specific capacity(1505 mA h g-1 at 0.1 C) and excellent cycling stability at 1 C over 300 cycles, giving rise to a capacity retention of 91.7% and an average capacity decline of 0.03%cycle-1.展开更多
Iron disulfide is considered to be a potential anode material for sodium-ion batteries due to its high theoretical capacity. However, its applications are seriously limited by the weak conductivity and large volume ch...Iron disulfide is considered to be a potential anode material for sodium-ion batteries due to its high theoretical capacity. However, its applications are seriously limited by the weak conductivity and large volume change, which results in low reversible capacity and poor cycling stability.Herein, reduced graphene oxide-wrapped FeS_2(FeS_2/rGO)composite was fabricated to achieve excellent electrochemical performance via a facile two-step method. The introduction of rGO effectively improved the conductivity,BET surface area, and structural stability of the FeS_2 active material, thus endowing it with high specific capacity, good rate capability, as well as excellent cycling stability. Electrochemical measurements show that the FeS_2/rGO composite had a high initial discharge capacity of 1263.2 mAh gg^(-1) at 100 mA gg^(-1) and a high discharge capacity of 344 mAh gg^(-1) at 10 A gg^(-1), demonstrating superior rate performance. After 100 cycles at 100 mA gg^(-1),the discharge capacity remained at 609.5 mAh g^(-1), indicating the excellent cycling stability of the FeS_2/rGO electrode.展开更多
The Nickel-rich layered cathode materials charged to 4.5 V can obtain a specific capacity of more than 200 m Ah g^(-1).However,the nickel-rich layered cathode materials suffer from the severe capacity fade during high...The Nickel-rich layered cathode materials charged to 4.5 V can obtain a specific capacity of more than 200 m Ah g^(-1).However,the nickel-rich layered cathode materials suffer from the severe capacity fade during high-voltage cycling,which is related to the phase transformation and the surface sides reactions caused by the lattice oxygen evolution.Here,the simultaneous construction of a Mg,Ti-based surface integrated layer and bulk doping through Mg,Ti surface treatment could suppress the lattice oxygen evolution of Nirich material at deep charging.More importantly,Mg and Ti are co-doped into the particles surface to form an Mg_(2)TiO_(4) and Mg_(0.5–x)Ti_(2–y)(PO_(4))_(3) outer layer with Mg and Ti vacancies.In the constructed surface integrated layer,the reverse electric field in the Mg_(2)TiO_(4) effectively suppressed the outward migration of the lattice oxygen anions,while Mg_(0.5–x)Ti_(2–y)(PO_(4))_(3) outer layer with high electronic conductivity and good lithium ion conductor could effectively maintained the stability of the reaction interface during highvoltage cycling.Meanwhile,bulk Mg and Ti co-doping can mitigate the migration of Ni ions in the bulk to keep the stability of transition metal–oxygen(M-O)bond at deep charging.As a result,the NCM@MTP cathode shows excellent long cycle stability at high-voltage charging,which keep high capacity retention of 89.3%and 84.3%at 1 C after 200 and 100 cycles under room and elevated temperature of 25 and 55°C,respectively.This work provides new insights for manipulating the surface chemistry of electrode materials to suppress the lattice oxygen evolution at high charging voltage.展开更多
Target micromotion not only plays an important role in target recognition but also leads to esoteric characteristics in synthetic aperture radar (SAR) imaging. This paper finds out an interesting phenomenon, i.e. th...Target micromotion not only plays an important role in target recognition but also leads to esoteric characteristics in synthetic aperture radar (SAR) imaging. This paper finds out an interesting phenomenon, i.e. the angular extent effect, in micro-motion target images formulated by the polar format algorithm. A micromotion target takes on multiple pairs of paired echoes (PEs) around the true point, and each PE extends for an angle which is exactly equal to the angular extent of the synthetic aperture, regardless of the micromotion frequency. The effect is derived and interpreted by using the characteristics of Bessel functions. Then it is demonstrated by simulation experiments of a target with different micromotion frequencies. The revelation and interpretation of the effect is highly beneficial to micromotion-target SAR image understanding as wel as target recognition.展开更多
Establishing covalent heterointerfaces with face-to-face contact is promising for advanced energy storage,while challenge remains on how to inhibit the anisotropic growth of nucleated crystals on the matrix.Herein,fac...Establishing covalent heterointerfaces with face-to-face contact is promising for advanced energy storage,while challenge remains on how to inhibit the anisotropic growth of nucleated crystals on the matrix.Herein,faceto-face covalent bridging in-between the 2 D-nanosheets/graphene heterostructure is constructed by intentionally prebonding of laser-manufactured amorphous and metastable nanoparticles on graphene,where the amorphous nanoparticles were designed via the competitive oxidation of Sn-O and Sn-S bonds,and metastable feature was employed to facilitate the formation of the C-S-Sn covalent bonding in-between the heterostructure.The face-to-face bridging of ultrathin SnS;nanosheets on graphene enables the heterostructure huge covalent coupling area and high loading and thus renders unimpeded electron/ion transfer pathways and indestructible electrode structure,and impressive reversible capacity and rate capability for sodium-ion batteries,which rank among the top in records of the SnS_(2)-based anodes.Present work thus provides an alternative of constructing heterostructures with planar interfaces for electrochemical energy storage and even beyond.展开更多
We develop an efficient method for polished metallic sphere’s scattering prediction in terahertz band when its frequency dispersion property is considered. By deducing scattering solution of the lossy metallic sphere...We develop an efficient method for polished metallic sphere’s scattering prediction in terahertz band when its frequency dispersion property is considered. By deducing scattering solution of the lossy metallic sphere, the radar cross section(RCS)of different metallic spheres is given at terahertz frequencies. The investigation of the RCS of polished metallic spheres shows the normalized RCS is always same to the metals’ normal incidence reflectivity when the sphere becomes electrically large. The metals which have high reflectivity(such as Al, Cu, Ag and Au) show that the corresponding RCS of the spheres is almost πa2 in terahertz band. The sphere’s RCS of the transition metal such as Fe begins to decrease obviously since the far infrared.展开更多
The Nickel-rich layered cathode materials have been considered as promising cathode for lithium-ion batteries(LIBs),which due to it can achieve a high capacity of than 200 mAh g^(-1)under a high cutoff voltage of4.5 V...The Nickel-rich layered cathode materials have been considered as promising cathode for lithium-ion batteries(LIBs),which due to it can achieve a high capacity of than 200 mAh g^(-1)under a high cutoff voltage of4.5 V.However,the nickel-rich layered cathode materials show severely capacity fading at high voltage cycling,induced by the hybrid O anion and cation redox promote O^(α-)(α<2)migration in the crystal lattice under high charge voltage,lead to the instability of the oxygen skeleton and oxygen evolution,promote the phase transition and electrolyte decomposition.Here,Li_(1-x)TMO_(2-y)/Li_(2)SO_(4) hybrid layer is designed by a simple pyrolysis method to enhance the high voltage cycle stability of NCM.In such constructed hybrid layer,the inner spinel structure of Li_(1-x)TMO_(2-y)layer is the electron-rich state,which could form an electron cloud coupling with the NCM with surface oxygen vacancies,while Li_(2)SO_(4) is p-type semiconductors,thus constructing a heterojunction interface of Li_(1-x)TMO_(2-y)//Li_(2)SO_(4) and Li_(1-x)TMO_(2-y)//NCM,thereby generating internal self-built electric fields to inhibit the outward migration of bulk oxygen anions.Moreover,the internal self-built electric fields could not only strengthen the bonding force between the Li_(1-x)TMO_(2-y)/Li_(2)SO_(4) hybrid layer and host NCM material,but also boost the charge transfer.As consequence,the modified NCM materials show excellent electrochemical performance with capacity retention of 97.7%and 90.1%after 200 cycles at 4.3 V and 4.5 V,respectively.This work provides a new idea for the development of high energy density applications of Nickel-rich layered cathode materials.展开更多
Supercapacitor is a new type of energy storage device,which has the advantages of high-power property and long cycle life.In this study,three-dimensional graphene(3 D-GN)with oxygen doping and porous structure was pre...Supercapacitor is a new type of energy storage device,which has the advantages of high-power property and long cycle life.In this study,three-dimensional graphene(3 D-GN)with oxygen doping and porous structure was prepared from graphene oxide(GO)by an inexpensive sodium chloride(NaCl)template,as a promising electrode material for the supercapacitor.The structure,morphology,specific surface area,pore size,of the sample were characterized by XRD,SEM,TEM and BET techniques.The electrochemical performances of the sample were tested by CV and CDC techniques.The 3 D-GE product is a threedimensional nano material with hierarchical porous structures,its specific surface area is much larger than that of routine stacked graphene(GN),and it contains a large number of mesoporous and macropores,a small amount of micropores.The capacitance characteristics of the 3 D-GN electrode material are excellent,showing high specific capacitance(173.5 F·g^(-1)at 1 A·g^(-1)),good rate performance(109.2 F·g^(-1)at 8 A·g^(-1))and long cycle life(88%capacitance retention after 10,000 cycles at 8 A·g^(-1))展开更多
基金financially supported by the project of the National Natural Science Foundation of China(52202115 and 52172101)the China Postdoctoral Science Foundation(2022M722586)+2 种基金the Natural Science Foundation of Chongqing,China(CSTB2022NSCQ-MSX1085)the Shaanxi Science and Technology Innovation Team(2023-CX-TD-44)the Fundamental Research Funds for the Central Universities(3102019JC005 and G2022KY0604)。
文摘Low-temperature processed electron transport layer(ETL)of TiO_(2)that is widely used in planar perovskite solar cells(PSCs)has inherent low carrier mobility,resulting in insufficient photogenerated elec-tron transport and thus recombination loss at buried interface.Herein,we demonstrate an effective strategy of laser embedding of p-n homojunctions in the TiO_(2)ETL to accelerate electron transport in PSCs,through localized build-in electric fields that enables boosted electron mobility by two orders of magnitude.Such embedding is found significantly helpful for not only the enhanced crystallization quality of TiO_(2)ETL,but the fabrication of perovskite films with larger-grain and the less-trap-states.The embedded p-n homojunction enables also the modulation of interfacial energy level between perovskite layers and ETLs,favoring for the reduced voltage deficit of PSCs.Benefiting from these merits,the formamidinium lead iodide(FAPbI_(3))PSCs employing such ETLs deliver a champion efficiency of 25.50%,along with much-improved device stability under harsh conditions,i.e.,maintain over 95%of their initial efficiency after operation at maximum power point under continuous heat and illumination for 500 h,as well as mixed-cation PSCs with a champion efficiency of 22.02%and over 3000 h of ambient storage under humidity stability of 40%.Present study offers new possibilities of regulating charge transport layers via p-n homojunction embedding for high performance optoelectronics.
基金financially supported by the project of the National Natural Science Foundation of China (Grant Nos.51972270,52322203)the Key Research and Development Program of Shaanxi Province (Grant NO.2024GH-ZDXM-21)the Fundamental Research Funds for the Central Universities (Grant Nos.G2022KY0607,23GH0202277).
文摘Exploiting high-performance yet low-cost hard carbon anodes is crucial to advancing the state-of-the-art sodium-ion batteries.However,the achievement of superior initial Coulombic efficiency(ICE)and high Na-storage capacity via low-temperature carbonization remains challenging due to the presence of tremendous defects with few closed pores.Here,a facile hybrid carbon framework design is proposed from the polystyrene precursor bearing distinct molecular bridges at a low pyrolysis temperature of 800℃ via in situ fusion and embedding strategy.This is realized by integrating triazine-and carbonylcrosslinked polystyrene nanospheres during carbonization.The triazine crosslinking allows in situ fusion of spheres into layered carbon with low defects and abundant closed pores,which serves as a matrix for embedding the well-retained carbon spheres with nanopores/defects derived from carbonyl crosslinking.Therefore,the hybrid hard carbon with intimate interface showcases synergistic Na ions storage behavior,showing an ICE of 70.2%,a high capacity of 279.3 mAh g^(-1),and long-term 500 cycles,superior to carbons from the respective precursor and other reported carbons fabricated under the low carbonization temperature.The present protocol opens new avenues toward low-cost hard carbon anode materials for high-performance sodiumion batteries.
基金This work was partially supported by the National Natural Science Foundation of China(Grant Nos.61906168,U20A20171)Zhejiang Provincial Natural Science Foundation of China(Grant Nos.LY23F020023,LY21F020027)Construction of Hubei Provincial Key Laboratory for Intelligent Visual Monitoring of Hydropower Projects(Grant Nos.2022SDSJ01).
文摘In clinical practice,the microscopic examination of urine sediment is considered an important in vitro examination with many broad applications.Measuring the amount of each type of urine sediment allows for screening,diagnosis and evaluation of kidney and urinary tract disease,providing insight into the specific type and severity.However,manual urine sediment examination is labor-intensive,time-consuming,and subjective.Traditional machine learning based object detection methods require hand-crafted features for localization and classification,which have poor generalization capabilities and are difficult to quickly and accurately detect the number of urine sediments.Deep learning based object detection methods have the potential to address the challenges mentioned above,but these methods require access to large urine sediment image datasets.Unfortunately,only a limited number of publicly available urine sediment datasets are currently available.To alleviate the lack of urine sediment datasets in medical image analysis,we propose a new dataset named UriSed2K,which contains 2465 high-quality images annotated with expert guidance.Two main challenges are associated with our dataset:a large number of small objects and the occlusion between these small objects.Our manuscript focuses on applying deep learning object detection methods to the urine sediment dataset and addressing the challenges presented by this dataset.Specifically,our goal is to improve the accuracy and efficiency of the detection algorithm and,in doing so,provide medical professionals with an automatic detector that saves time and effort.We propose an improved lightweight one-stage object detection algorithm called Discriminatory-YOLO.The proposed algorithm comprises a local context attention module and a global background suppression module,which aid the detector in distinguishing urine sediment features in the image.The local context attention module captures context information beyond the object region,while the global background suppression module emphasizes objects in uninformative backgrounds.We comprehensively evaluate our method on the UriSed2K dataset,which includes seven categories of urine sediments,such as erythrocytes(red blood cells),leukocytes(white blood cells),epithelial cells,crystals,mycetes,broken erythrocytes,and broken leukocytes,achieving the best average precision(AP)of 95.3%while taking only 10 ms per image.The source code and dataset are available at https://github.com/binghuiwu98/discriminatoryyolov5.
基金financially supported by National Key R&D Program for International Cooperation(No.2021YFE0115100)the project of the National Natural Science Foundation of China(Nos.51872240,51972270 and 52172101)+4 种基金Key Research and Development Program of Shaanxi Province(No.2021ZDLGY14-08 and 2022KWZ-04)Natural Science Foundation of Shaanxi Province(2020JZ-07)the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(2021-TS-03)the Fundamental Research Funds for the Central Universities(No.3102019JC005 and G2022KY0604)the Research Fund of the State Key Laboratory of Solid Lubrication(CAS),China(LSL-2007)。
文摘Composite solid electrolytes(CSEs)with poly(ethylene oxide)(PEO)have become fairly prevalent for fabricating high-performance solid-state lithium metal batteries due to their high Li~+solvating capability,flexible processability and low cost.However,unsatisfactory room-temperature ionic conductivity,weak interfacial compatibility and uncontrollable Li dendrite growth seriously hinder their progress.Enormous efforts have been devoted to combining PEO with ceramics either as fillers or major matrix with the rational design of two-phase architecture,spatial distribution and content,which is anticipated to hold the key to increasing ionic conductivity and resolving interfacial compatibility within CSEs and between CSEs/electrodes.Unfortunately,a comprehensive review exclusively discussing the design,preparation and application of PEO/ceramic-based CSEs is largely lacking,in spite of tremendous reviews dealing with a broad spectrum of polymers and ceramics.Consequently,this review targets recent advances in PEO/ceramicbased CSEs,starting with a brief introduction,followed by their ionic conduction mechanism,preparation methods,and then an emphasis on resolving ionic conductivity and interfacial compatibility.Afterward,their applications in solid-state lithium metal batteries with transition metal oxides and sulfur cathodes are summarized.Finally,a summary and outlook on existing challenges and future research directions are proposed.
基金supported by Foundation for the Sichuan University and Zigong City Joint research project(2021CDZG-2)the Foundation for the Sichuan University and Yibin City Strategic Cooperation Project(2020CDYB-32)the Guangxi Key Laboratory of Low Carbon Energy Material(2020GKLLCEM02)。
文摘Fluoride ferrous(FeF_(2))is viewed as a promising conversion cathode material for next-generation lithiumion batteries(LIBs)due to its high theoretical specific capacity and low cost.Unfortunately,issues such as poor intrinsic conductivity,iron dissolution,and phase separation hinder the application of FeF_(2)in highenergy cathodes.Here,a pressure-induced morphology control method is designed to prepare coralloidlike FeF_(2)nanocrystals with nitrogen-rich carbon coating(c-FeF_(2)@NC).The coralloid-like interconnected crystal structure of c-FeF_(2)@NC contributes to reducing interfacial resistance and enhancing the topotactic transformation during the conversion reaction,and the nitrogen-rich carbon(NC)coating can enhance interfacial stability and kinetic performance.When used as a conversion cathode for LIBs,c-FeF_(2)@NC exhibits a high initial reversible capacity of 503.57 mA h g^(-1)and excellent cycling stability of497.61 m A h g^(-1)with a low capacity decay of 1.19%over 50 cycles at 0.1 A/g.Even at 1 A/g,a stable capacity of 263.78 mA h g^(-1)can still be retained after 200 cycles.The capability of c-FeF_(2)@NC as a conversion cathode for sodium-ion batteries(SIBs)was also evaluated to expand its field of application.Furthermore,two kinds of full batteries have been assembled by employing c-FeF_(2)@NC as cathodes and quantitative limited-Li(LLi)and pre-lithiated reduced graphene oxide(PGO)as anodes,respectively,to envisage the feasibility of practical applications of conversion materials.
基金supported by the Special Project for the Central Government to Guide Local Technological Development (GUIKE ZY20198008)the Guangxi Technology Base and talent Subject (GUIKE AD20238012,AD20297086)+5 种基金the Natural Science Foundation of Guangxi Province (2021GXNSFDA075012)the National Natural Science Foundation of China (51902108,52104298,22169004)the National Natural Science Foundation of China (U20A20249)the Regional Innovation and Development Joint Fundthe Guangxi Innovation Driven Development Subject (GUIKE AA19182020,19254004)the Special Fund for Guangxi Distinguished Expert。
文摘Charging P2-Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)to 4.5 V for higher capacity is enticing.However,it leads to severe capacity fading,ascribing to the lattice oxygen evolution and the P2-O2 phase transformation.Here,the Mg Fe_(2)O_(4) coating and Mg,Fe co-doping were constructed simultaneously by Mg,Fe surface treatment to suppress lattice oxygen evolution and P2-O2 phase transformation of P2-Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)at deep charging.Through ex-situ X-ray diffraction(XRD)tests,we found that the Mg,Fe bulk co-doping could reduce the repulsion between transition metals and Na+/vacancies ordering,thus inhibiting the P2-O2 phase transition and significantly reducing the irreversible volume change of the material.Meanwhile,the internal electric field formed by the dielectric polarization of Mg Fe_(2)O_(4) effectively inhibits the outward migration of oxidized O^(a-)(a<2),thereby suppressing the lattice oxygen evolution at deep charging,confirmed by in situ Raman and ex situ XPS techniques.P2-Na NM@MF-3 shows enhanced high-voltage cycling performance with capacity retentions of 84.8% and 81.3%at 0.1 and 1 C after cycles.This work sheds light on regulating the surface chemistry for Na-layered oxide materials to enhance the high-voltage performance of Na-ion batteries.
基金the National Natural Science Foundation of China(51972270,51702262,51911530212,51872240,51672225,61805201)the China Postdoctoral Science Foundation(2018T111093,2018M643732,2018BSHYDZZ57)+3 种基金the Natural Science Foundation of Shaanxi Province(2020JZ-07)the Key Research and Development Program of Shaanxi Province(2019TSLGY07-03)the Fundamental Research Funds for the Central Universities(3102019JC005 and 3102019ghxm004)the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(2019-QZ-03).
文摘Onedimensional porous carbons bearing high surface areas and sufficient heteroatom doped functionalities are essential for advanced electrochemical energy storage devices,especially for developing freestanding film electrodes.Here we develop a porous,nitrogenenriched,freestanding hollow carbon nanofiber(PNFHCF)electrode material via filtration of polypyrrole(PPy)hollow nanofibers formed by in situ selfdegraded templateassisted strategy,followed by NH3assisted carbonization.The PNFHCF retains the freestanding film morphology that is composed of threedimensional networks from the entanglement of 1D nanofiber and delivers 3.7fold increase in specific surface area(592 m^(2)g^(-1))compared to the carbon without NH_(3)treatment(FHCF).In spite of the enhanced specific surface area,PNFHCF still exhibits comparable high content of surface N functionalities(8.8%,atom fraction)to FHCF.Such developed hierarchical porous structure without sacrificing N doping functionalities together enables the achievement of high capacity,highrate property and good cycling stability when applied as selfsupporting anode in lithiumion batteries,superior to those of FHCF without NH3 treatment.
文摘This worked aimed to test the hypothesis that L-alanyl-L-glutamine(Ala-Gln)improves the varicocele-induced testicular injury,which causes male infertility.For this purpose,fifty adult male Wistar rats received the varicocele(VC)surgery at the left renal vein.Biomarkers were determined 2,4,and 8 weeks after VC(n=10/each detection).Four weeks after VC,rats received Ala-Gln(1.125 g/kg)treatment with and or saline for 1 week(n=10/each group).Rats in the sham group were also detected for biomarkers at 2,4,and 8 weeks(n=10/each detection).VC caused testicular injury detected by hematoxylin–eosin(H&E)staining,immunohistochemistry,and TUNEL assay.HSP70 mRNA was detected quantitative RT-PCR,SOD,and CAT by nitroblue tetrazolium(NBT)method and 8-OHDG by ELISA.The results showed that varicocele induced injury in the testes.The weight of the left testes was lower than that of the right testes in VC-bearing rats(p<0.01).The relative numbers of sustentacular and spermatogenic cells were decreased after VC(p<0.01).In sham-4 wk,VC-4wk,VC-5wk and Ala-Gln groups,the apoptosis index was 5.10±1.14,13.22±3.63,33.62±3.56 and 22.33±2.61,relative level of HSP70 mRNA 1.00±0.12,0.53±0.05,0.51±0.04 and 1.62±0.15 fold,SOD 16.4±0.23,13.4±0.17,10.01±1.06 and 19.53±2.26 U/mg protein,CAT 2.16±0.31,1.07±0.28,and 1.31±0.26 and 3.46±0.71 U/mg,8-OHDG 5.23±0.67,6.81±0.78,7.16±1.22 and 4.14±0.73 pg/μg DNA,respectively(p<0.01).Our results suggest that Ala-Gln prevented the VC-induced testicular injury.We have firstly reported that Ala-Gln protects against varicocele-induced testicular injuries by up-regulation of HSP70 and antioxidants,SOD and CAT,and down-regulation of oxidant 8-OHDG,resulting in reducing apoptosis in the testis.
基金the Guangdong Provincial Natural Science Foundation(nos.2017A030313283,2017A030313083)National Natural Science Foundation of China(NSFC,no.51602109)。
文摘The sluggish redox kinetics and shuttle effect of soluble polysulfides intermediate primarily restrict the electrochemical performance of lithium–sulfur(Li–S) batteries. To address this issue, rational design of high–efficiency sulfur host is increasingly demanded to accelerate the polysulfides conversion during charge/discharge process. Herein, we propose a macro–mesoporous sulfur host(Co@NC), which comprises highly dispersed cobalt nanoparticles embedding in N–doped ultrathin carbon nanosheets. Co@NC is simply synthesized via a carbon nitride–derived pyrolysis approach. Owing to the highly conductive graphene–like matrix and well defined porous structure, the designed multifunctional Co@NC host enables rapid electron/ion transport, electrolyte penetration and effective sulfur trapping. More significantly,N heteroatoms and homogeneous Co nanocatalysts in the graphitic carbon nanosheets could serve as chemisorption sites as well as electrocatalytic centers for sulfur species. These Co–N active sites can synergistically facilitate the redox conversion kinetics and mitigate the shuttling of polysulfides, thus leading to improved electrochemical cycling performance of Li–S batteries. As a consequence, the S/Co@NC cathode demonstrates high initial specific capacity(1505 mA h g-1 at 0.1 C) and excellent cycling stability at 1 C over 300 cycles, giving rise to a capacity retention of 91.7% and an average capacity decline of 0.03%cycle-1.
基金supported by National Natural Science Foundation of China (51702138, 51702079)Natural Science Foundation of Jiangsu Province (BK20160213)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Iron disulfide is considered to be a potential anode material for sodium-ion batteries due to its high theoretical capacity. However, its applications are seriously limited by the weak conductivity and large volume change, which results in low reversible capacity and poor cycling stability.Herein, reduced graphene oxide-wrapped FeS_2(FeS_2/rGO)composite was fabricated to achieve excellent electrochemical performance via a facile two-step method. The introduction of rGO effectively improved the conductivity,BET surface area, and structural stability of the FeS_2 active material, thus endowing it with high specific capacity, good rate capability, as well as excellent cycling stability. Electrochemical measurements show that the FeS_2/rGO composite had a high initial discharge capacity of 1263.2 mAh gg^(-1) at 100 mA gg^(-1) and a high discharge capacity of 344 mAh gg^(-1) at 10 A gg^(-1), demonstrating superior rate performance. After 100 cycles at 100 mA gg^(-1),the discharge capacity remained at 609.5 mAh g^(-1), indicating the excellent cycling stability of the FeS_2/rGO electrode.
基金supported by the National Natural Science Foundation of China(51902108,51762006,51964013)the Special Projects for Central Government to Guide Local Technological Development(GUIKE ZY20198008)+2 种基金the Guangxi InnovationDriven Development Subject(GUIKE AA19182020,GUIKE AA19254004)the Guangxi Technology Base and Talent Subject(GUIKE AD18126001,GUIKE AD20999012,GUIKE AD20297086)the Special Fund for Guangxi Distinguished Expert。
文摘The Nickel-rich layered cathode materials charged to 4.5 V can obtain a specific capacity of more than 200 m Ah g^(-1).However,the nickel-rich layered cathode materials suffer from the severe capacity fade during high-voltage cycling,which is related to the phase transformation and the surface sides reactions caused by the lattice oxygen evolution.Here,the simultaneous construction of a Mg,Ti-based surface integrated layer and bulk doping through Mg,Ti surface treatment could suppress the lattice oxygen evolution of Nirich material at deep charging.More importantly,Mg and Ti are co-doped into the particles surface to form an Mg_(2)TiO_(4) and Mg_(0.5–x)Ti_(2–y)(PO_(4))_(3) outer layer with Mg and Ti vacancies.In the constructed surface integrated layer,the reverse electric field in the Mg_(2)TiO_(4) effectively suppressed the outward migration of the lattice oxygen anions,while Mg_(0.5–x)Ti_(2–y)(PO_(4))_(3) outer layer with high electronic conductivity and good lithium ion conductor could effectively maintained the stability of the reaction interface during highvoltage cycling.Meanwhile,bulk Mg and Ti co-doping can mitigate the migration of Ni ions in the bulk to keep the stability of transition metal–oxygen(M-O)bond at deep charging.As a result,the NCM@MTP cathode shows excellent long cycle stability at high-voltage charging,which keep high capacity retention of 89.3%and 84.3%at 1 C after 200 and 100 cycles under room and elevated temperature of 25 and 55°C,respectively.This work provides new insights for manipulating the surface chemistry of electrode materials to suppress the lattice oxygen evolution at high charging voltage.
基金supported by the National Natural Science Foundationof China(6130214861101182)
文摘Target micromotion not only plays an important role in target recognition but also leads to esoteric characteristics in synthetic aperture radar (SAR) imaging. This paper finds out an interesting phenomenon, i.e. the angular extent effect, in micro-motion target images formulated by the polar format algorithm. A micromotion target takes on multiple pairs of paired echoes (PEs) around the true point, and each PE extends for an angle which is exactly equal to the angular extent of the synthetic aperture, regardless of the micromotion frequency. The effect is derived and interpreted by using the characteristics of Bessel functions. Then it is demonstrated by simulation experiments of a target with different micromotion frequencies. The revelation and interpretation of the effect is highly beneficial to micromotion-target SAR image understanding as wel as target recognition.
基金This work was financially supported by the project of National Key R&D Program for International Cooperation(2021YFE0115100)the National Natural Science Foundation of China(Nos.51872240,51972270 and 52172101)+5 种基金Shaanxi Province Key Research and Development Program(2021ZDLGY14-08)Natural Science Foundation of Shaanxi Province(2020JZ-07)the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(2021-TS-03)the Fundamental Research Funds for the Central Universities(3102019JC005)the Research Fund of the State Key Laboratory of Solid Lubrication(CAS),China(LSL-2007)Open access funding provided by Shanghai Jiao Tong University
文摘Establishing covalent heterointerfaces with face-to-face contact is promising for advanced energy storage,while challenge remains on how to inhibit the anisotropic growth of nucleated crystals on the matrix.Herein,faceto-face covalent bridging in-between the 2 D-nanosheets/graphene heterostructure is constructed by intentionally prebonding of laser-manufactured amorphous and metastable nanoparticles on graphene,where the amorphous nanoparticles were designed via the competitive oxidation of Sn-O and Sn-S bonds,and metastable feature was employed to facilitate the formation of the C-S-Sn covalent bonding in-between the heterostructure.The face-to-face bridging of ultrathin SnS;nanosheets on graphene enables the heterostructure huge covalent coupling area and high loading and thus renders unimpeded electron/ion transfer pathways and indestructible electrode structure,and impressive reversible capacity and rate capability for sodium-ion batteries,which rank among the top in records of the SnS_(2)-based anodes.Present work thus provides an alternative of constructing heterostructures with planar interfaces for electrochemical energy storage and even beyond.
基金supported by the National Science Fund for Young Scientists of China(6130214861571011)
文摘We develop an efficient method for polished metallic sphere’s scattering prediction in terahertz band when its frequency dispersion property is considered. By deducing scattering solution of the lossy metallic sphere, the radar cross section(RCS)of different metallic spheres is given at terahertz frequencies. The investigation of the RCS of polished metallic spheres shows the normalized RCS is always same to the metals’ normal incidence reflectivity when the sphere becomes electrically large. The metals which have high reflectivity(such as Al, Cu, Ag and Au) show that the corresponding RCS of the spheres is almost πa2 in terahertz band. The sphere’s RCS of the transition metal such as Fe begins to decrease obviously since the far infrared.
基金supported by the National Natural Science Foundation of China(51902108,51762006,51964013)the Special Projects for Central Government to Guide Local Technological Development(GUIKE ZY20198008)+2 种基金the Guangxi InnovationDriven Development Subject(GUIKE AA19182020,GUIKE AA19254004)the Guangxi Technology Base and Talent Subject(GUIKE AD18126001,GUIKE AD20999012,GUIKE AD20297086)the Special Fund for Guangxi Distinguished Expert。
文摘The Nickel-rich layered cathode materials have been considered as promising cathode for lithium-ion batteries(LIBs),which due to it can achieve a high capacity of than 200 mAh g^(-1)under a high cutoff voltage of4.5 V.However,the nickel-rich layered cathode materials show severely capacity fading at high voltage cycling,induced by the hybrid O anion and cation redox promote O^(α-)(α<2)migration in the crystal lattice under high charge voltage,lead to the instability of the oxygen skeleton and oxygen evolution,promote the phase transition and electrolyte decomposition.Here,Li_(1-x)TMO_(2-y)/Li_(2)SO_(4) hybrid layer is designed by a simple pyrolysis method to enhance the high voltage cycle stability of NCM.In such constructed hybrid layer,the inner spinel structure of Li_(1-x)TMO_(2-y)layer is the electron-rich state,which could form an electron cloud coupling with the NCM with surface oxygen vacancies,while Li_(2)SO_(4) is p-type semiconductors,thus constructing a heterojunction interface of Li_(1-x)TMO_(2-y)//Li_(2)SO_(4) and Li_(1-x)TMO_(2-y)//NCM,thereby generating internal self-built electric fields to inhibit the outward migration of bulk oxygen anions.Moreover,the internal self-built electric fields could not only strengthen the bonding force between the Li_(1-x)TMO_(2-y)/Li_(2)SO_(4) hybrid layer and host NCM material,but also boost the charge transfer.As consequence,the modified NCM materials show excellent electrochemical performance with capacity retention of 97.7%and 90.1%after 200 cycles at 4.3 V and 4.5 V,respectively.This work provides a new idea for the development of high energy density applications of Nickel-rich layered cathode materials.
基金supported by National Natural Science Foundation of China(22078071,51762006 and 51864007)Natural Science Foundation of Guangdong Province(2020A1515010344)+4 种基金Science and Technology Innovation Project of Guangdong Province College Students(733316)Guangxi Key Research and Development Program of Science and Technology(GUIKE AB17195065and AB17129011)Guangxi Technology Base and Talent Subject(GUIKE AD18126001 and GUIKE AD17195084)Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2019)the program for Innovative Research Team of Guangdong University of Petrochemical Technology。
文摘Supercapacitor is a new type of energy storage device,which has the advantages of high-power property and long cycle life.In this study,three-dimensional graphene(3 D-GN)with oxygen doping and porous structure was prepared from graphene oxide(GO)by an inexpensive sodium chloride(NaCl)template,as a promising electrode material for the supercapacitor.The structure,morphology,specific surface area,pore size,of the sample were characterized by XRD,SEM,TEM and BET techniques.The electrochemical performances of the sample were tested by CV and CDC techniques.The 3 D-GE product is a threedimensional nano material with hierarchical porous structures,its specific surface area is much larger than that of routine stacked graphene(GN),and it contains a large number of mesoporous and macropores,a small amount of micropores.The capacitance characteristics of the 3 D-GN electrode material are excellent,showing high specific capacitance(173.5 F·g^(-1)at 1 A·g^(-1)),good rate performance(109.2 F·g^(-1)at 8 A·g^(-1))and long cycle life(88%capacitance retention after 10,000 cycles at 8 A·g^(-1))