Symmetric Na-ion cells using the NASICON-structured electrodes could simplify the manufacturing process,reduce the cost,facilitate the recycling post-process,and thus attractive in the field of large-scale stationary ...Symmetric Na-ion cells using the NASICON-structured electrodes could simplify the manufacturing process,reduce the cost,facilitate the recycling post-process,and thus attractive in the field of large-scale stationary energy storage.However,the long-term cycling performance of such batteries is usually poor.This investigation reveals the unavoidable side reactions between the NASICON-type Na_(3)V_(2)(PO_(4))_(3)(NVP)anode and the commercial liquid electrolyte,leading to serious capacity fading in the symmetric NVP//NVP cells.To resolve this issue,an all-solid-state composite electrolyte is used to replace the liquid electrolyte so that to overcome the side reaction and achieve high anode/electrolyte interfacial stability.The ferroelectric engineering could further improve the interfacial ion conduction,effectively reducing the electrode/electrolyte interfacial resistances.The NVP//NVP cell using the ferroelectric-engineered composite electrolyte can achieve a capacity retention of 86.4%after 650 cycles.Furthermore,the electrolyte can also be used to match the Prussianblue cathode NaxFeyFe(CN)_(6−z)·nH_(2)O(NFFCN).Outstanding long-term cycling stability has been obtained in the all-solid-state NVP//NFFCN cell over 9000 cycles at a current density of 500 mA g^(-1),with a fading rate as low as 0.005%per cycle.展开更多
Rechargeable Zn-air batteries(ZAB)have drawn extensive attention due to their eco-friendliness and safety.However,the lack of high-performance and low-cost oxygen redox reactions(OER and ORR)catalysts has become one o...Rechargeable Zn-air batteries(ZAB)have drawn extensive attention due to their eco-friendliness and safety.However,the lack of high-performance and low-cost oxygen redox reactions(OER and ORR)catalysts has become one of the main stumbling blocks in their development.Herein,we successfully fabricate a CoFe nanobubble encapsulated in nitrogen-doped carbon nanocage on wood carbon support(CoFe@NC/WC)via pyrolysis of a novel Prussian blue analog(PBA)/spruce precursor.The hierarchical CoFe@NC/WC catalyst exhibits an excellent potential difference of 0.74 V between the OER potential at 10 mA cm^(-2)and half-wave potential of ORR in 0.1 M KOH,comparable to recently reported preeminent electrocatalysts.Further,CoFe@NC/WC shows outstanding electrochemical performance in liquid ZAB,with a peak power density of 138.9 mW cm^(-2)and a specific capacity of 763.5 mAh g^(-1).More importantly,a bacterial cellulose nanofiber reinforced polyacrylic acid(BC-PAA)hydrogel electrolyte shows ultrahigh tensile-breaking stress of 1.58 MPa.In conjunction with the as-prepared CoFe@NC/WC catalyst,BC-PAA-based wearable ZAB displays impressive rechargeability and foldability,and can power portable electronics,such as electronic timer and mobile phone,in bent states.This work provides a new approach toward high-activity and low-cost catalysts for ZAB.展开更多
Multifunctional electrochromic-induced rechargeable aqueous batteries(MERABs) integrate electrochromism and aqueous ion batteries into one platform, which is able to deliver the conversion and storage of photo-thermal...Multifunctional electrochromic-induced rechargeable aqueous batteries(MERABs) integrate electrochromism and aqueous ion batteries into one platform, which is able to deliver the conversion and storage of photo-thermal-electrochemical sources.Aqueous ion batteries compensate for the drawbacks of slow kinetic reactions and unsatisfied storage capacities of electrochromic devices. On the other hand, electrochromic technology can enable dynamically regulation of solar light and heat radiation. However,MERABs still face several technical issues, including a trade-off between electrochromic and electrochemical performance, low conversion efficiency and poor service life. In this connection, novel device configuration and electrode materials, and an optimized compatibility need to be considered for multidisciplinary applications. In this review,the unique advantages, key challenges and advanced applications are elucidated in a timely and comprehensive manner. Firstly, the prerequisites for effective integration of the working mechanism and device configuration, as well as the choice of electrode materials are examined. Secondly, the latest advances in the applications of MERABs are discussed, including wearable, self-powered, integrated systems and multisystem conversion. Finally, perspectives on the current challenges and future development are outlined, highlighting the giant leap required from laboratory prototypes to large-scale production and eventual commercialization.展开更多
Scarring is one of the biggest areas of unmet need in the long-term success of glaucoma filtration surgery.Quantitative evaluation of the scar tissue and the post-operative structure with micron scale resolution facil...Scarring is one of the biggest areas of unmet need in the long-term success of glaucoma filtration surgery.Quantitative evaluation of the scar tissue and the post-operative structure with micron scale resolution facilitates development of anti-fibrosis techniques.However,the distinguishment of conjunctiva,sclera and the scar tissue in the surgical area still relies on pathologists'experience.Since polarized light imaging is sensitive to anisotropic properties of the media,it is ideal for discrimination of scar in the subconjunctival and episcleral area by characterizing small differences between proportion,organization and the orientation of the fibers.In this paper,we defined the conjunctiva,sclera,and the scar tissue as three target tissues after glaucoma filtration surgery and obtained their polarization characteristics from the tissue sections by a Mueller matrix microscope.Discrimination score based on parameters derived from Mueller matrix and machine learning was calculated and tested as a diagnostic index.As a result,the discrimination score of three target tissues showed significant difference between each other(p<0.001).The visualization of the discrimination results showed significant contrast between target tissues.This study proved that Mueller matrix imaging is effective in ocular scar discrimination and paves the way for its application on other forms of ocular fibrosis as a substitute or supplementary for clinical practice.展开更多
Recently,security issues of smart contracts are arising great attention due to the enormous financial loss caused by vulnerability attacks.There is an increasing need to detect similar codes for hunting vulnerability ...Recently,security issues of smart contracts are arising great attention due to the enormous financial loss caused by vulnerability attacks.There is an increasing need to detect similar codes for hunting vulnerability with the increase of critical security issues in smart contracts.Binary similarity detection that quantitatively measures the given code diffing has been widely adopted to facilitate critical security analysis.However,due to the difference between common programs and smart contract,such as diversity of bytecode generation and highly code homogeneity,directly adopting existing graph matching and machine learning based techniques to smart contracts suffers from low accuracy,poor scalability and the limitation of binary similarity on function level.Therefore,this paper investigates graph neural network to detect smart contract binary code similarity at the program level,where we conduct instruction-level normalization to reduce the noise code for smart contract pre-processing and construct contract control flow graphs to represent smart contracts.In particular,two improved Graph Convolutional Network(GCN)and Message Passing Neural Network(MPNN)models are explored to encode the contract graphs into quantitatively vectors,which can capture the semantic information and the program-wide control flow information with temporal orders.Then we can efficiently accomplish the similarity detection by measuring the distance between two targeted contract embeddings.To evaluate the effectiveness and efficient of our proposed method,extensive experiments are performed on two real-world datasets,i.e.,smart contracts from Ethereum and Enterprise Operation System(EOS)blockchain-based platforms.The results show that our proposed approach outperforms three state-of-the-art methods by a large margin,achieving a great improvement up to 6.1%and 17.06%in accuracy.展开更多
Rechargeable batteries of high energy density and overall performance are becoming a critically important technology in the rapidly changing society of the twenty-first century.While lithium-ion batteries have so far ...Rechargeable batteries of high energy density and overall performance are becoming a critically important technology in the rapidly changing society of the twenty-first century.While lithium-ion batteries have so far been the dominant choice,numerous emerging applications call for higher capacity,better safety and lower costs while maintaining sufficient cyclability.The design space for potentially better alternatives is extremely large,with numerous new chemistries and architectures being simultaneously explored.These include other insertion ions(e.g.sodium and numerous multivalent ions),conversion electrode materials(e.g.silicon,metallic anodes,halides and chalcogens)and aqueous and solid electrolytes.However,each of these potential“beyond lithium-ion”alternatives faces numerous challenges that often lead to very poor cyclability,especially at the commercial cell level,while lithium-ion batteries continue to improve in performance and decrease in cost.This review examines fundamental principles to rationalise these numerous developments,and in each case,a brief overview is given on the advantages,advances,remaining challenges preventing cell-level implementation and the state-of-the-art of the solutions to these challenges.Finally,research and development results obtained in academia are compared to emerging commercial examples,as a commentary on the current and near-future viability of these“beyond lithium-ion”alternatives.展开更多
Underwater target recognition is a key technology for underwater acoustic countermeasure.How to classify and recognize underwater targets according to the noise information of underwater targets has been a hot topic i...Underwater target recognition is a key technology for underwater acoustic countermeasure.How to classify and recognize underwater targets according to the noise information of underwater targets has been a hot topic in the field of underwater acoustic signals.In this paper,the deep learning model is applied to underwater target recognition.Improved anti-noise Power-Normalized Cepstral Coefficients(ia-PNCC)is proposed,based on PNCC applied to underwater noises.Multitaper and normalized Gammatone filter banks are applied to improve the anti-noise capacity.The method is combined with a convolutional neural network in order to recognize the underwater target.Experiment results show that the acoustic feature presented by ia-PNCC has lower noise and are wellsuited to underwater target recognition using a convolutional neural network.Compared with the combination of convolutional neural network with single acoustic feature,such as MFCC(Mel-scale Frequency Cepstral Coefficients)or LPCC(Linear Prediction Cepstral Coefficients),the combination of the ia-PNCC with a convolutional neural network offers better accuracy for underwater target recognition.展开更多
While the sulfur conversion reaction kinetics in Li–S batteries is nowadays improved by the use of appropriate electrocatalysts,it remains a challenge for the batteries to perform well under the lean electrolyte cond...While the sulfur conversion reaction kinetics in Li–S batteries is nowadays improved by the use of appropriate electrocatalysts,it remains a challenge for the batteries to perform well under the lean electrolyte condition where polysulfide shuttle,electrode passivation and the loss of electrolyte due to side reactions,are aggravated.These challenges are addressed in this study by the tandem use of a polysulfide conversion catalyst and a redox–targeting mediator in a gel sulfur cathode.Specifically,the gel cathode reduces the polysulfide mobility and hence the polysulfide shuttle and the passivation of the lithium anode by the crossover polysulfides.The redox mediator restrains the deposition of inactive sulfur species in the cathode thereby enabling the Fe–N and Co–N co–doped carbon catalyst to prolong its catalytic activity.Consequently,the integrated catalytic system is able to increase the discharge capacity of high–loading (6.8 mg cm^(-2)) lean–electrolyte (4.0μL mg^(-1)) Li–S batteries from~630 to~1316 m Ah g^(-1),concurrently with an improvement of the cycle life (600 cycles with 46%capacity retention at 1.0 m A cm^(-2)).Redox mediator assisted catalysis in a gel cathode is therefore an effective strategy to extend the application of the sulfur conversion catalyst in lean electrolyte Li–S batteries.展开更多
Carbonaceous materials are the most promising candidates as the anode for sodium-ion batteries (SIBs), however, they still suffer from low electric conductivity and sluggish sodium ion (Na+) reaction kinetics. Appropr...Carbonaceous materials are the most promising candidates as the anode for sodium-ion batteries (SIBs), however, they still suffer from low electric conductivity and sluggish sodium ion (Na+) reaction kinetics. Appropriate composition modulation using heteroatoms doping and structure optimization is highly desired. A basic empirical understanding of the structure-capacity relationship is also urgent in tackling the above problems. Herein, multi-functional nitrogen (N) doped carbon micro-rods with enlarged interlayer spacing are synthesized and investigated as the anode in SIBs, showing an ultra-stable capacity of 161.5 mAh g^(−1) at 2 A g^(−1) for over 5000 cycles. Experimental investigations and first-principle calculations indicate that the enlarged interlayer spacing can facilitate Na+ intercalation and N doping can guarantee the high electric conductivity and favorable electrochemical active sites. Additionally, pyridinic N is theoretically proved to be more effective to enhance Na+ adsorption than pyrrolic N due to the lower adsorption energy and stronger binding energy with Na+. Full SIBs show a high capacity and cyclability, making the biomass-derived carbon micro-rods to be a promising anode for practical SIBs applications.展开更多
One of the problems experienced in marine geophysical exploration is that the layered features in the migration imaging profile are blurred and the seismic energy reflected is weaker in the middle or lower parts. In t...One of the problems experienced in marine geophysical exploration is that the layered features in the migration imaging profile are blurred and the seismic energy reflected is weaker in the middle or lower parts. In this study we model the seismic wavefield records in the undulating seafloor when there is both a slight change and significant change in seafloor topography to analyze its influence on the seismic reflection data and migration imaging profiles. We compare and analyze the wave field records collected at the same point on the original and modified velocity models, and the cross-bonding resulting migration imaging profiles. The results show that whether the seismic reflection data collection is performed along the direction of the survey line or against the direction of the survey line, slight changes in the seafloor topography have little effect on the wave field records and the migration profile, while significant changes in the seafloor topography have great effect on both the wave field records and migration profile.展开更多
Borda sorting algorithm is a kind of improvement algorithm based on weighted position sorting algorithm,it is mainly suitable for the high duplication of search results,for the independent search results,the effect is...Borda sorting algorithm is a kind of improvement algorithm based on weighted position sorting algorithm,it is mainly suitable for the high duplication of search results,for the independent search results,the effect is not very good and the computing method of relative score in Borda sorting algorithm is according to the rule of the linear regressive,but position relationship cannot fully represent the correlation changes.aimed at this drawback,the new sorting algorithm is proposed in this paper,named PMS-Sorting algorithm,firstly the position score of the returned results is standardized processing,and the similarity retrieval word string with the query results is combined into the algorithm,the similarity calculation method is also improved,through the experiment,the improved algorithm is superior to traditional sorting algorithm.展开更多
The pruning algorithms for sparse least squares support vector regression machine are common methods, and easily com- prehensible, but the computational burden in the training phase is heavy due to the retraining in p...The pruning algorithms for sparse least squares support vector regression machine are common methods, and easily com- prehensible, but the computational burden in the training phase is heavy due to the retraining in performing the pruning process, which is not favorable for their applications. To this end, an im- proved scheme is proposed to accelerate sparse least squares support vector regression machine. A major advantage of this new scheme is based on the iterative methodology, which uses the previous training results instead of retraining, and its feasibility is strictly verified theoretically. Finally, experiments on bench- mark data sets corroborate a significant saving of the training time with the same number of support vectors and predictive accuracy compared with the original pruning algorithms, and this speedup scheme is also extended to classification problem.展开更多
Objective Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) constitute a rare and heterogeneous group of tumors with varied biology and still constitute a diagnostic and therapeutic challenge for physicians...Objective Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) constitute a rare and heterogeneous group of tumors with varied biology and still constitute a diagnostic and therapeutic challenge for physicians of all specialties. In the present study, we aimed to review and study the clinicopathological characteristics of GEP-NENs applying the World Health Organization (WHO) 2010 grading criterion. Methods A total of 48 patients were enrolled in the study. The study included patients diagnosed with GEP-NENs who were treated and followed up at our Hospital from January 2013 to December 2017. Data regarding clinicopathological features of the patients were retrospectively evaluated. The expression of neuroendocrine markers was measured using the immunohistochemical Ultra SensitiveTM S-P method of staining in 48 cases of primary GEP-NENs; and serum levels of neuron-specific enolase, carbohydrate an-tigen 19-9, and carcinoembryonic antigen in 36 GEP-NEN patients were measured using the electrochemiluminescence method. Results The median age at presentation was 59.3 (range 48-82) years, and 39 cases (81.3%) were seen between the 5th and 6th decades. There was a male predilection (male: female=3:1). In 79.2% cases (38/48), tumors were hormonally nonfunctional. The most common presentation was abdominal pain, and the most frequent primary site of the tumor was the rectum, followed by the stomach (n = 15, 31.3%), colon (n = 5, 10.4%), and so on. Of the 48 tumors, 16 (33.3%) were G1,6 (12.5%) cases were G2, 16 (33.3%) were neuroendocrine carcinoma (NEC), and 10 (20.8%) were mixed adenoneuroendocrine carcinoma (MANEC). According to the AJCC/UICC classification, 45.8% (n = 22) were diagnosed at low stage (stage Ⅰ or Ⅱ) while 54.2% (n = 26) were diagnosed at high stage (stage Ⅲ or Ⅳ) (the majority of NEC, G3, and MANEC). A male preponderance was noted for all tumors except for G2 neoplasms, which showed no gender predilection. Thirty-nine patients underwent endoscopic biopsy. The lesions in 18.8% (n = 9) of the patients were indentified only radiologically. After the surgical procedures, 36 had at least one follow-up visit with a median follow-up duration of 5 months; the mean follow-up period was 28 ± 16 months. The one- year and three-year survival rates were 72.2% (26/36) and 61.1% (22/36), respectively. This study did not find an effect of grade 3 (G3) of tumor on the short-term clinical outcome of these patients. In the survival analysis, NEN G3, higher stage (stage Ⅲ or Ⅳ) according to the AJCC/UICC classification (P 〈 0.05), and metastases at diagnosis (P 〈 0.05) were associated with poorer prognosis. Conclusion Most GEP-NENs are nonfunctional and nonspecific in presentation. The most frequent primary site of the tumor was the rectum and the commonest ages at diagnosis were the 5th and 6th decades. Endoscopic biopsy is the main diagnostic and histological grading method for GEP-NEN. In the survival analysis, NEN G3, a higher stage according to the AJCC/UICC classification, and metastases at diagnosis are associated with poorer prognosis.展开更多
With the progression of sea exploration and offshore engineering, electronic charts have come to see widespread use in many intelligent applications. Like other digital products, electronic charts are easy to duplicat...With the progression of sea exploration and offshore engineering, electronic charts have come to see widespread use in many intelligent applications. Like other digital products, electronic charts are easy to duplicate and distribute. Some watermarking solutions have proven defective to prevent copying of electronic charts because it’s as easy to forge as it is to redistribute. If the problems of copyright infringement cannot be solved, the creation of these electronic charts will be limited. The most important characteristic of electronic charts is the topological relationships among vertices, but few algorithms can control this feature. A new watermarking algorithm is here proposed as a means of copyright protection, in which the watermarks will be hosted in the electronic chart by taking into account the preservation of the topology. Sometimes, additional vertices are inserted into the middle of two adjacent vertices, sometimes not, which are governed by the value of the watermark. Experiments show that the improved algorithm is better than similar algorithms; it was found to resist geometric attacks and format exchange attacks.展开更多
Aqueous zinc‐ion batteries(ZIBs)are regarded as among the most promising candidates for large‐scale grid energy storage,owing to their high safety,low costs,and environmental friendliness.Over the past decade,vanadi...Aqueous zinc‐ion batteries(ZIBs)are regarded as among the most promising candidates for large‐scale grid energy storage,owing to their high safety,low costs,and environmental friendliness.Over the past decade,vanadium oxides,which are exemplified by V2O5,have been widely developed as a class of cathode materials for ZIBs,where the relatively high theoretical capacity and structural stability are among the main considerations.However,there are considerable challenges in the construction of vanadium‐based ZIBs with high capacity,long lifespan,and excellent rate performance.Simple widenings of the interlayer spacing in the layered vanadium oxides by pre‐intercalations appear to have reached their limitations in improving the energy density and other key performance parameters of ZIBs,although various metal ions(Na+,Ca2+,and Al3+)and even organic cations/groups have been explored.Herein,we discuss the advances made more recently,and also the challenges faced by the high‐performance vanadium oxides(V2O5‐based)cathodes,where there are several strategies to improve their electrochemical performance ranging from the new structural designs down to sub‐nano‐scopic/molecular/atomic levels,including cation pre‐intercalation,structural water optimization,and defect engineering,to macroscopic structural modifications.The key principles for an optimal structural design of the V2O5‐based cathode materials for high energy density and fast‐charging aqueous ZIBs are examined,aiming at paving the way for developing energy storage designed for those large scales,high safety,and low‐cost systems.展开更多
All solid-state batteries(ASSBs)are the holy grails of rechargeable batteries,where extensive searches are ongoing in the pursuit of ideal solid-state electrolytes.Nevertheless,there is still a long way off to the sat...All solid-state batteries(ASSBs)are the holy grails of rechargeable batteries,where extensive searches are ongoing in the pursuit of ideal solid-state electrolytes.Nevertheless,there is still a long way off to the satisfactorily high(enough)ionic conductivity,long-term stability and especially being able to form compatible interfaces with the solid electrodes.Herein,we have explored ionic transport behavior and high mobility in the sub-nano pore networks in the framework structures.Macroscopically,the frameworked electrolyte behaves as a solid,and however in the(sub)-nano scales,the very limited number of solvent molecules in confinement makes them completely different from that in liquid electrolyte.Differentiated from a liquid-electrolyte counterpart,the interactions between the mobile ions and surrounding molecules are subject to dramatic changes,leading to a high ionic conductivity at room temperature with a low activation energy.Li+ions in the sub-nano cages of the network structure are highly mobile and diffuse rather independently,where the rate-limiting step of ions crossing cages is driven by the local concentration gradient and the electrostatic interactions between Li^(+)ions.This new class of frameworked electrolytes(FEs)with both high ionic conductivity and desirable interface with solid electrodes are demonstrated to work with Li-ion batteries,where the ASSB with LiFePO_(4)shows a highly stable electrochemical performance of over 450 cycles at 2℃ at room temperature,with an almost negligible capacity fade of 0.03‰ each cycle.In addition,the FE shows outstanding flexibility and anti-flammability,which are among the key requirements of large-scale applications.展开更多
Glaucoma is the leading cause of irreversible blindness,affecting 111 million people by 2040 worldwide.Intraocular pressure(IOP)is the only controllable risk factor for the disease and current treatment options seek t...Glaucoma is the leading cause of irreversible blindness,affecting 111 million people by 2040 worldwide.Intraocular pressure(IOP)is the only controllable risk factor for the disease and current treatment options seek to reduce IOP via daily taking eye drops.However,shortcomings of eye drops,such as poor bioavailability and unsatisfied therapeutic effects,may lead to inadequate patient compliance.In this study,an effective brimonidine(BRI)-loaded silicone rubber(SR)implant coated with polydimethylsiloxane(BRI@SR@PDMS)is designed and fully investigated for IOP reduction treatment.The in vitro BRI release from BRI@SR@PDMS implant reveals a more sustainable trend lasting over 1 month,with a gradually declined immediate drug concentration.The carrier materials show no cytotoxicity on human corneal epithelial cells and mice corneal epithelial cells in vitro.After administrated into rabbit’s conjunctival sac,the BRI@SR@PDMS implant releases BRI in a sustained fashion and effectively reduces IOP for 18 days with great biosafety.In contrast,BRI eye drops only maintain IOP-lowering effect for 6 h.Therefore,as a substitute of eye drops,the BRI@SR@PDMS implant can be applied as a promising non-invasive platform to achieve long-term IOP-lowering in patients suffering from ocular hypertension or glaucoma.展开更多
基金supported by the National University of Singapore(Chongqing)Research Institute,National University of Singapore,Chongqing Postdoctoral Research Special Funding(2021XM2002)Overseas Postdoctoral Research Start-up Funding,Natural Science Foundation of Chongqing(cstc2021jcyjmsxmX0086)+1 种基金Chongqing Innovative Project for oversea-experience researchers(cx2023037)the Open Project Program of Fujian Key Laboratory of Special Energy Manufacturing.
文摘Symmetric Na-ion cells using the NASICON-structured electrodes could simplify the manufacturing process,reduce the cost,facilitate the recycling post-process,and thus attractive in the field of large-scale stationary energy storage.However,the long-term cycling performance of such batteries is usually poor.This investigation reveals the unavoidable side reactions between the NASICON-type Na_(3)V_(2)(PO_(4))_(3)(NVP)anode and the commercial liquid electrolyte,leading to serious capacity fading in the symmetric NVP//NVP cells.To resolve this issue,an all-solid-state composite electrolyte is used to replace the liquid electrolyte so that to overcome the side reaction and achieve high anode/electrolyte interfacial stability.The ferroelectric engineering could further improve the interfacial ion conduction,effectively reducing the electrode/electrolyte interfacial resistances.The NVP//NVP cell using the ferroelectric-engineered composite electrolyte can achieve a capacity retention of 86.4%after 650 cycles.Furthermore,the electrolyte can also be used to match the Prussianblue cathode NaxFeyFe(CN)_(6−z)·nH_(2)O(NFFCN).Outstanding long-term cycling stability has been obtained in the all-solid-state NVP//NFFCN cell over 9000 cycles at a current density of 500 mA g^(-1),with a fading rate as low as 0.005%per cycle.
基金supported by the Innovation and Technology Commission(Grant no.PRP/032/20FX)the RFBR(Grant no.20-03-00772)
文摘Rechargeable Zn-air batteries(ZAB)have drawn extensive attention due to their eco-friendliness and safety.However,the lack of high-performance and low-cost oxygen redox reactions(OER and ORR)catalysts has become one of the main stumbling blocks in their development.Herein,we successfully fabricate a CoFe nanobubble encapsulated in nitrogen-doped carbon nanocage on wood carbon support(CoFe@NC/WC)via pyrolysis of a novel Prussian blue analog(PBA)/spruce precursor.The hierarchical CoFe@NC/WC catalyst exhibits an excellent potential difference of 0.74 V between the OER potential at 10 mA cm^(-2)and half-wave potential of ORR in 0.1 M KOH,comparable to recently reported preeminent electrocatalysts.Further,CoFe@NC/WC shows outstanding electrochemical performance in liquid ZAB,with a peak power density of 138.9 mW cm^(-2)and a specific capacity of 763.5 mAh g^(-1).More importantly,a bacterial cellulose nanofiber reinforced polyacrylic acid(BC-PAA)hydrogel electrolyte shows ultrahigh tensile-breaking stress of 1.58 MPa.In conjunction with the as-prepared CoFe@NC/WC catalyst,BC-PAA-based wearable ZAB displays impressive rechargeability and foldability,and can power portable electronics,such as electronic timer and mobile phone,in bent states.This work provides a new approach toward high-activity and low-cost catalysts for ZAB.
基金support by Shanghai Municipal Education Commission (No. 2019-01-07-00-09E00020), for research conducted at the Shanghai Universitysupport by Independent depolyment project of Qinghai Institute of Salt Lakes, Chinese Academy of Sciences (E260GC0401)support by the Singapore National Research Foundation (NRF-CRP26-2021-0003, NRF), for research conducted at the National University of Singapore。
文摘Multifunctional electrochromic-induced rechargeable aqueous batteries(MERABs) integrate electrochromism and aqueous ion batteries into one platform, which is able to deliver the conversion and storage of photo-thermal-electrochemical sources.Aqueous ion batteries compensate for the drawbacks of slow kinetic reactions and unsatisfied storage capacities of electrochromic devices. On the other hand, electrochromic technology can enable dynamically regulation of solar light and heat radiation. However,MERABs still face several technical issues, including a trade-off between electrochromic and electrochemical performance, low conversion efficiency and poor service life. In this connection, novel device configuration and electrode materials, and an optimized compatibility need to be considered for multidisciplinary applications. In this review,the unique advantages, key challenges and advanced applications are elucidated in a timely and comprehensive manner. Firstly, the prerequisites for effective integration of the working mechanism and device configuration, as well as the choice of electrode materials are examined. Secondly, the latest advances in the applications of MERABs are discussed, including wearable, self-powered, integrated systems and multisystem conversion. Finally, perspectives on the current challenges and future development are outlined, highlighting the giant leap required from laboratory prototypes to large-scale production and eventual commercialization.
基金supported by the Natural Science Foundation of Beijing(No.7194266)Beijing Municipal Administration of Hospitals'Youth Program(No.QML20191206)+1 种基金Fundamental Research Funds for the Central Public Welfare Research Institutes(No.XTCX2021002)Scientific and technological innovation project of China Academy of Chinese Medical Sciences(No.CI2021A00601).
文摘Scarring is one of the biggest areas of unmet need in the long-term success of glaucoma filtration surgery.Quantitative evaluation of the scar tissue and the post-operative structure with micron scale resolution facilitates development of anti-fibrosis techniques.However,the distinguishment of conjunctiva,sclera and the scar tissue in the surgical area still relies on pathologists'experience.Since polarized light imaging is sensitive to anisotropic properties of the media,it is ideal for discrimination of scar in the subconjunctival and episcleral area by characterizing small differences between proportion,organization and the orientation of the fibers.In this paper,we defined the conjunctiva,sclera,and the scar tissue as three target tissues after glaucoma filtration surgery and obtained their polarization characteristics from the tissue sections by a Mueller matrix microscope.Discrimination score based on parameters derived from Mueller matrix and machine learning was calculated and tested as a diagnostic index.As a result,the discrimination score of three target tissues showed significant difference between each other(p<0.001).The visualization of the discrimination results showed significant contrast between target tissues.This study proved that Mueller matrix imaging is effective in ocular scar discrimination and paves the way for its application on other forms of ocular fibrosis as a substitute or supplementary for clinical practice.
基金supported by the Basic Research Program(No.JCKY2019210B029)Network threat depth analysis software(KY10800210013).
文摘Recently,security issues of smart contracts are arising great attention due to the enormous financial loss caused by vulnerability attacks.There is an increasing need to detect similar codes for hunting vulnerability with the increase of critical security issues in smart contracts.Binary similarity detection that quantitatively measures the given code diffing has been widely adopted to facilitate critical security analysis.However,due to the difference between common programs and smart contract,such as diversity of bytecode generation and highly code homogeneity,directly adopting existing graph matching and machine learning based techniques to smart contracts suffers from low accuracy,poor scalability and the limitation of binary similarity on function level.Therefore,this paper investigates graph neural network to detect smart contract binary code similarity at the program level,where we conduct instruction-level normalization to reduce the noise code for smart contract pre-processing and construct contract control flow graphs to represent smart contracts.In particular,two improved Graph Convolutional Network(GCN)and Message Passing Neural Network(MPNN)models are explored to encode the contract graphs into quantitatively vectors,which can capture the semantic information and the program-wide control flow information with temporal orders.Then we can efficiently accomplish the similarity detection by measuring the distance between two targeted contract embeddings.To evaluate the effectiveness and efficient of our proposed method,extensive experiments are performed on two real-world datasets,i.e.,smart contracts from Ethereum and Enterprise Operation System(EOS)blockchain-based platforms.The results show that our proposed approach outperforms three state-of-the-art methods by a large margin,achieving a great improvement up to 6.1%and 17.06%in accuracy.
基金J.Wang acknowledges the support by MOE,Singapore Ministry of Education(MOE2018-T2-2-095)for research work conducted at the National University of Singapore.Z.L.Liu acknowledges the A*STAR’s Central Research Funds(CRF)Award(Project:SC25/21-111312)+1 种基金Y.Gao acknowledges financial support by ST Engineering Advanced Material Engineering Pte.Ltd.and Singapore Economic Development BoardOpen access funding provided by Shanghai Jiao Tong University
文摘Rechargeable batteries of high energy density and overall performance are becoming a critically important technology in the rapidly changing society of the twenty-first century.While lithium-ion batteries have so far been the dominant choice,numerous emerging applications call for higher capacity,better safety and lower costs while maintaining sufficient cyclability.The design space for potentially better alternatives is extremely large,with numerous new chemistries and architectures being simultaneously explored.These include other insertion ions(e.g.sodium and numerous multivalent ions),conversion electrode materials(e.g.silicon,metallic anodes,halides and chalcogens)and aqueous and solid electrolytes.However,each of these potential“beyond lithium-ion”alternatives faces numerous challenges that often lead to very poor cyclability,especially at the commercial cell level,while lithium-ion batteries continue to improve in performance and decrease in cost.This review examines fundamental principles to rationalise these numerous developments,and in each case,a brief overview is given on the advantages,advances,remaining challenges preventing cell-level implementation and the state-of-the-art of the solutions to these challenges.Finally,research and development results obtained in academia are compared to emerging commercial examples,as a commentary on the current and near-future viability of these“beyond lithium-ion”alternatives.
基金supported by the National Natural Science Foundation of China(grant numbers:81602688,81773245,and 81972858)the Natural Science Foundation of Chongqing(cstc2016jcyjA0531)+2 种基金the Science and Technology Innovation Special Project of Chongqing Social Undertak ings and Livelihood Security(cstc2017shmsA130108)the Chongqing Innovation Leading Talents Program(cstccxljrc201910)the Cultivation Program for Clinical Research Talents of Army Medical University(2018XLC1010)。
基金This work was funded by the National Natural Science Foundation of China under Grant(Nos.61772152,61502037)the Basic Research Project(Nos.JCKY2016206B001,JCKY2014206C002,JCKY2017604C010)and the Technical Foundation Project(No.JSQB2017206C002).
文摘Underwater target recognition is a key technology for underwater acoustic countermeasure.How to classify and recognize underwater targets according to the noise information of underwater targets has been a hot topic in the field of underwater acoustic signals.In this paper,the deep learning model is applied to underwater target recognition.Improved anti-noise Power-Normalized Cepstral Coefficients(ia-PNCC)is proposed,based on PNCC applied to underwater noises.Multitaper and normalized Gammatone filter banks are applied to improve the anti-noise capacity.The method is combined with a convolutional neural network in order to recognize the underwater target.Experiment results show that the acoustic feature presented by ia-PNCC has lower noise and are wellsuited to underwater target recognition using a convolutional neural network.Compared with the combination of convolutional neural network with single acoustic feature,such as MFCC(Mel-scale Frequency Cepstral Coefficients)or LPCC(Linear Prediction Cepstral Coefficients),the combination of the ia-PNCC with a convolutional neural network offers better accuracy for underwater target recognition.
基金the financial support provided by the National University of Singapore。
文摘While the sulfur conversion reaction kinetics in Li–S batteries is nowadays improved by the use of appropriate electrocatalysts,it remains a challenge for the batteries to perform well under the lean electrolyte condition where polysulfide shuttle,electrode passivation and the loss of electrolyte due to side reactions,are aggravated.These challenges are addressed in this study by the tandem use of a polysulfide conversion catalyst and a redox–targeting mediator in a gel sulfur cathode.Specifically,the gel cathode reduces the polysulfide mobility and hence the polysulfide shuttle and the passivation of the lithium anode by the crossover polysulfides.The redox mediator restrains the deposition of inactive sulfur species in the cathode thereby enabling the Fe–N and Co–N co–doped carbon catalyst to prolong its catalytic activity.Consequently,the integrated catalytic system is able to increase the discharge capacity of high–loading (6.8 mg cm^(-2)) lean–electrolyte (4.0μL mg^(-1)) Li–S batteries from~630 to~1316 m Ah g^(-1),concurrently with an improvement of the cycle life (600 cycles with 46%capacity retention at 1.0 m A cm^(-2)).Redox mediator assisted catalysis in a gel cathode is therefore an effective strategy to extend the application of the sulfur conversion catalyst in lean electrolyte Li–S batteries.
基金J.G.Sun appreciates the scholarship support from China Scholarship Council(CSC)under grant No.201706050153.
文摘Carbonaceous materials are the most promising candidates as the anode for sodium-ion batteries (SIBs), however, they still suffer from low electric conductivity and sluggish sodium ion (Na+) reaction kinetics. Appropriate composition modulation using heteroatoms doping and structure optimization is highly desired. A basic empirical understanding of the structure-capacity relationship is also urgent in tackling the above problems. Herein, multi-functional nitrogen (N) doped carbon micro-rods with enlarged interlayer spacing are synthesized and investigated as the anode in SIBs, showing an ultra-stable capacity of 161.5 mAh g^(−1) at 2 A g^(−1) for over 5000 cycles. Experimental investigations and first-principle calculations indicate that the enlarged interlayer spacing can facilitate Na+ intercalation and N doping can guarantee the high electric conductivity and favorable electrochemical active sites. Additionally, pyridinic N is theoretically proved to be more effective to enhance Na+ adsorption than pyrrolic N due to the lower adsorption energy and stronger binding energy with Na+. Full SIBs show a high capacity and cyclability, making the biomass-derived carbon micro-rods to be a promising anode for practical SIBs applications.
基金The National Natural Science Foundation of China under contract Nos 41504084 and 41274120
文摘One of the problems experienced in marine geophysical exploration is that the layered features in the migration imaging profile are blurred and the seismic energy reflected is weaker in the middle or lower parts. In this study we model the seismic wavefield records in the undulating seafloor when there is both a slight change and significant change in seafloor topography to analyze its influence on the seismic reflection data and migration imaging profiles. We compare and analyze the wave field records collected at the same point on the original and modified velocity models, and the cross-bonding resulting migration imaging profiles. The results show that whether the seismic reflection data collection is performed along the direction of the survey line or against the direction of the survey line, slight changes in the seafloor topography have little effect on the wave field records and the migration profile, while significant changes in the seafloor topography have great effect on both the wave field records and migration profile.
基金This work was funded by the National Natural Science Foundation of China under Grant(No.61772152 and No.61502037)the Basic Research Project(Nos.JCKY2016206B001,JCKY2014206C002 and JCKY2017604C010)the Technical Foundation Project(No.JSQB2017206C002).
文摘Borda sorting algorithm is a kind of improvement algorithm based on weighted position sorting algorithm,it is mainly suitable for the high duplication of search results,for the independent search results,the effect is not very good and the computing method of relative score in Borda sorting algorithm is according to the rule of the linear regressive,but position relationship cannot fully represent the correlation changes.aimed at this drawback,the new sorting algorithm is proposed in this paper,named PMS-Sorting algorithm,firstly the position score of the returned results is standardized processing,and the similarity retrieval word string with the query results is combined into the algorithm,the similarity calculation method is also improved,through the experiment,the improved algorithm is superior to traditional sorting algorithm.
基金supported by the National Natural Science Foundation of China(50576033)
文摘The pruning algorithms for sparse least squares support vector regression machine are common methods, and easily com- prehensible, but the computational burden in the training phase is heavy due to the retraining in performing the pruning process, which is not favorable for their applications. To this end, an im- proved scheme is proposed to accelerate sparse least squares support vector regression machine. A major advantage of this new scheme is based on the iterative methodology, which uses the previous training results instead of retraining, and its feasibility is strictly verified theoretically. Finally, experiments on bench- mark data sets corroborate a significant saving of the training time with the same number of support vectors and predictive accuracy compared with the original pruning algorithms, and this speedup scheme is also extended to classification problem.
基金Supported by a grant from the Jining Medical University Teacher’s Research Support Fund(No.2018)
文摘Objective Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) constitute a rare and heterogeneous group of tumors with varied biology and still constitute a diagnostic and therapeutic challenge for physicians of all specialties. In the present study, we aimed to review and study the clinicopathological characteristics of GEP-NENs applying the World Health Organization (WHO) 2010 grading criterion. Methods A total of 48 patients were enrolled in the study. The study included patients diagnosed with GEP-NENs who were treated and followed up at our Hospital from January 2013 to December 2017. Data regarding clinicopathological features of the patients were retrospectively evaluated. The expression of neuroendocrine markers was measured using the immunohistochemical Ultra SensitiveTM S-P method of staining in 48 cases of primary GEP-NENs; and serum levels of neuron-specific enolase, carbohydrate an-tigen 19-9, and carcinoembryonic antigen in 36 GEP-NEN patients were measured using the electrochemiluminescence method. Results The median age at presentation was 59.3 (range 48-82) years, and 39 cases (81.3%) were seen between the 5th and 6th decades. There was a male predilection (male: female=3:1). In 79.2% cases (38/48), tumors were hormonally nonfunctional. The most common presentation was abdominal pain, and the most frequent primary site of the tumor was the rectum, followed by the stomach (n = 15, 31.3%), colon (n = 5, 10.4%), and so on. Of the 48 tumors, 16 (33.3%) were G1,6 (12.5%) cases were G2, 16 (33.3%) were neuroendocrine carcinoma (NEC), and 10 (20.8%) were mixed adenoneuroendocrine carcinoma (MANEC). According to the AJCC/UICC classification, 45.8% (n = 22) were diagnosed at low stage (stage Ⅰ or Ⅱ) while 54.2% (n = 26) were diagnosed at high stage (stage Ⅲ or Ⅳ) (the majority of NEC, G3, and MANEC). A male preponderance was noted for all tumors except for G2 neoplasms, which showed no gender predilection. Thirty-nine patients underwent endoscopic biopsy. The lesions in 18.8% (n = 9) of the patients were indentified only radiologically. After the surgical procedures, 36 had at least one follow-up visit with a median follow-up duration of 5 months; the mean follow-up period was 28 ± 16 months. The one- year and three-year survival rates were 72.2% (26/36) and 61.1% (22/36), respectively. This study did not find an effect of grade 3 (G3) of tumor on the short-term clinical outcome of these patients. In the survival analysis, NEN G3, higher stage (stage Ⅲ or Ⅳ) according to the AJCC/UICC classification (P 〈 0.05), and metastases at diagnosis (P 〈 0.05) were associated with poorer prognosis. Conclusion Most GEP-NENs are nonfunctional and nonspecific in presentation. The most frequent primary site of the tumor was the rectum and the commonest ages at diagnosis were the 5th and 6th decades. Endoscopic biopsy is the main diagnostic and histological grading method for GEP-NEN. In the survival analysis, NEN G3, a higher stage according to the AJCC/UICC classification, and metastases at diagnosis are associated with poorer prognosis.
基金This work was supported by the National Science Foundation of China under Grant No. 61202455, the National Science Foundation of China under Grant No. 61472096, Liaoning Science and Technology Project No. 2014302006 and the Specialized Foundation for the Basic Research Operating Expenses Program of Central College No. HEUCF100612, HEUCFT1202.
文摘With the progression of sea exploration and offshore engineering, electronic charts have come to see widespread use in many intelligent applications. Like other digital products, electronic charts are easy to duplicate and distribute. Some watermarking solutions have proven defective to prevent copying of electronic charts because it’s as easy to forge as it is to redistribute. If the problems of copyright infringement cannot be solved, the creation of these electronic charts will be limited. The most important characteristic of electronic charts is the topological relationships among vertices, but few algorithms can control this feature. A new watermarking algorithm is here proposed as a means of copyright protection, in which the watermarks will be hosted in the electronic chart by taking into account the preservation of the topology. Sometimes, additional vertices are inserted into the middle of two adjacent vertices, sometimes not, which are governed by the value of the watermark. Experiments show that the improved algorithm is better than similar algorithms; it was found to resist geometric attacks and format exchange attacks.
基金supported by the National Research Foundation(NRF)for research conducted at the National University of Singapore(CRP No.NRF‐CRP26‐2021‐0003)the Singapore Ministry of Education(Tier 1,No.A‐8000186‐01‐00).
文摘Aqueous zinc‐ion batteries(ZIBs)are regarded as among the most promising candidates for large‐scale grid energy storage,owing to their high safety,low costs,and environmental friendliness.Over the past decade,vanadium oxides,which are exemplified by V2O5,have been widely developed as a class of cathode materials for ZIBs,where the relatively high theoretical capacity and structural stability are among the main considerations.However,there are considerable challenges in the construction of vanadium‐based ZIBs with high capacity,long lifespan,and excellent rate performance.Simple widenings of the interlayer spacing in the layered vanadium oxides by pre‐intercalations appear to have reached their limitations in improving the energy density and other key performance parameters of ZIBs,although various metal ions(Na+,Ca2+,and Al3+)and even organic cations/groups have been explored.Herein,we discuss the advances made more recently,and also the challenges faced by the high‐performance vanadium oxides(V2O5‐based)cathodes,where there are several strategies to improve their electrochemical performance ranging from the new structural designs down to sub‐nano‐scopic/molecular/atomic levels,including cation pre‐intercalation,structural water optimization,and defect engineering,to macroscopic structural modifications.The key principles for an optimal structural design of the V2O5‐based cathode materials for high energy density and fast‐charging aqueous ZIBs are examined,aiming at paving the way for developing energy storage designed for those large scales,high safety,and low‐cost systems.
基金Singapore Ministry of Education,Grant/Award Number:A-8000186-01-00National Research Foundation(NRF)Singapore,Grant/Award Numbers:CRP NRF-CRP26-2021-0003,NRFCRP24-2020-0002A*STAR SERC CRF Award。
文摘All solid-state batteries(ASSBs)are the holy grails of rechargeable batteries,where extensive searches are ongoing in the pursuit of ideal solid-state electrolytes.Nevertheless,there is still a long way off to the satisfactorily high(enough)ionic conductivity,long-term stability and especially being able to form compatible interfaces with the solid electrodes.Herein,we have explored ionic transport behavior and high mobility in the sub-nano pore networks in the framework structures.Macroscopically,the frameworked electrolyte behaves as a solid,and however in the(sub)-nano scales,the very limited number of solvent molecules in confinement makes them completely different from that in liquid electrolyte.Differentiated from a liquid-electrolyte counterpart,the interactions between the mobile ions and surrounding molecules are subject to dramatic changes,leading to a high ionic conductivity at room temperature with a low activation energy.Li+ions in the sub-nano cages of the network structure are highly mobile and diffuse rather independently,where the rate-limiting step of ions crossing cages is driven by the local concentration gradient and the electrostatic interactions between Li^(+)ions.This new class of frameworked electrolytes(FEs)with both high ionic conductivity and desirable interface with solid electrodes are demonstrated to work with Li-ion batteries,where the ASSB with LiFePO_(4)shows a highly stable electrochemical performance of over 450 cycles at 2℃ at room temperature,with an almost negligible capacity fade of 0.03‰ each cycle.In addition,the FE shows outstanding flexibility and anti-flammability,which are among the key requirements of large-scale applications.
基金supported by the National Key Research and Development Program of China(2020YFA0715000)the National Natural Science Foundation of China(521722315197225951832004)+3 种基金the Fundamental Research Funds for the Central Universities(WUT:2020Ⅲ043GX2020Ⅲ015GX)the support by MOE,Singapore Ministry of Education(Tier 1,A-8000186-01-00)the funding support from Singapore A*STAR CRF Awardthe scholarship support from China Scholarship Council(CSC)under No.202106950024。
基金supported by the National Key Research and Development Program of China(2020YFA0112700)the State Key Program of National Natural Science Foundation of China(82030027)+6 种基金the Subject of Major Projects of National Natural Science Foundation of China(81790641)National Natural Science Foundation of China(81870630)Clinical Research Plan of SHDC(SHDC2020CR6029)the Scientific and Innovative Action Plan of Shanghai(19441900600)the Natural Science Foundation of Shanghai(19ZR1408300)the Science and Technology Commission of Shanghai Municipality(21Y11909900)Shanghai Municipal Health Commission(202240316).
文摘Glaucoma is the leading cause of irreversible blindness,affecting 111 million people by 2040 worldwide.Intraocular pressure(IOP)is the only controllable risk factor for the disease and current treatment options seek to reduce IOP via daily taking eye drops.However,shortcomings of eye drops,such as poor bioavailability and unsatisfied therapeutic effects,may lead to inadequate patient compliance.In this study,an effective brimonidine(BRI)-loaded silicone rubber(SR)implant coated with polydimethylsiloxane(BRI@SR@PDMS)is designed and fully investigated for IOP reduction treatment.The in vitro BRI release from BRI@SR@PDMS implant reveals a more sustainable trend lasting over 1 month,with a gradually declined immediate drug concentration.The carrier materials show no cytotoxicity on human corneal epithelial cells and mice corneal epithelial cells in vitro.After administrated into rabbit’s conjunctival sac,the BRI@SR@PDMS implant releases BRI in a sustained fashion and effectively reduces IOP for 18 days with great biosafety.In contrast,BRI eye drops only maintain IOP-lowering effect for 6 h.Therefore,as a substitute of eye drops,the BRI@SR@PDMS implant can be applied as a promising non-invasive platform to achieve long-term IOP-lowering in patients suffering from ocular hypertension or glaucoma.