Electrochemical reduction of CO_(2)(CO_(2)RR)coupled with renewable electrical energy is an attractive way of upgrading CO_(2)to value-added chemicals and closing the carbon cycle.However,CO_(2)RR electrocatalysts sti...Electrochemical reduction of CO_(2)(CO_(2)RR)coupled with renewable electrical energy is an attractive way of upgrading CO_(2)to value-added chemicals and closing the carbon cycle.However,CO_(2)RR electrocatalysts still suffer from high overpotential,and the complex reaction pathways of CO_(2)RR often lead to mixed products.Early research focuses on tuning the binding of reaction intermediates on electrocatalysts,and recent efforts have revealed that the design of electrolysis reactors is equally important for efficient and selective CO_(2)RR.In this review,we present an overview of recent advances and challenges toward achieving high activity and high selectivity in CO_(2)RR at ambient conditions,with a particular focus on the progress of CO_(2)RR electrocatalyst engineering and reactor design.Our discussion begins with three types of electrocatalysts for CO_(2)RR(noble metalbased,none-noble metal-based,and metal-free electrocatalysts),and then we examine systems-level strategies toward engineering specific components of the electrolyzer,including gas diffusion electrodes,electrolytes,and polymer electrolyte membranes.We close with future perspectives on catalyst development,in-situ/operando characterization,and electrolyzer performance evaluation in CO_(2)RR studies.展开更多
The chemical equilibrium and reaction kinetic behavior in the synthesis of polyoxymethylene dimethyl ethers (DMMn) were investigated over sulfated titania in order to reveal the decisive factor controlling the react...The chemical equilibrium and reaction kinetic behavior in the synthesis of polyoxymethylene dimethyl ethers (DMMn) were investigated over sulfated titania in order to reveal the decisive factor controlling the reaction. The results showed that the molar ratio of adjacent DMMn products in equilibrium solution had the same value, which depended absolutely on the reaction temperature. Meanwhile, the reactions had the same DMMn products distributions under varied reaction conditions. The equilibrium constants of the related step-wise reactions for DMMn formation were equal, which were calculated based on the bulk compositions of the reaction solution. And thus, the selectivity to DMMn was mainly controlled by the chemical equilibrium, i.e., thermodynamic control. In brief, the present results provide some guidance for future synthesis of DMMn.展开更多
Objective:Hepatocellular carcinoma(HCC)is a lethal global disease that requires an accurate diagnosis.We assessed the potential of 5 serum biomarkers(AFP,AFU,GGT-II,GPC3,and HGF)in the diagnosis of HCC.Methods:In this...Objective:Hepatocellular carcinoma(HCC)is a lethal global disease that requires an accurate diagnosis.We assessed the potential of 5 serum biomarkers(AFP,AFU,GGT-II,GPC3,and HGF)in the diagnosis of HCC.Methods:In this retrospective study,we measured the serum levels of each biomarker using ELISAs in 921 participants,including 298 patients with HCC,154 patients with chronic hepatitis(CH),122 patients with liver cirrhosis(LC),and 347 healthy controls from 3 hospitals.Patients negative for hepatitis B surface antigen and hepatitis C antibody(called"NBNC-HCC")and patients positive for the above indices(called"HBV-HCC and HCV-HCC")were enrolled.The selected diagnostic model was constructed using a training cohort(n=468),and a validation cohort(n=453)was used to validate our results.Receiver operating characteristic analysis was used to evaluate the diagnostic accuracy.Results:Theα-L-fucosidase(AFU)/α-fetoprotein(AFP)combination was best able to distinguish NBNC-HCC[area under the curve:0.986(95%confidence interval:0.958–0.997),sensitivity:92.6%,specificity:98.9%]from healthy controls in the test cohort.For screening populations at risk of developing HCC(CH and LC),the AFP/AFU combination improved the diagnostic specificity for early-stage HCC[area under the curve:0.776(0.712–0.831),sensitivity:52.5%,specificity:91.6%in the test group].In all-stage HBV-HCC and HCV-HCC,AFU was also the best candidate biomarker combined with AFP[area under the curve:0.835(0.784–0.877),sensitivity 69.1%,specificity:87.4%in the test group].All results were verified in the validation group.Conclusions:The AFP/AFU combination could be used to identify NBNC-HCC from healthy controls and hepatitis-related HCC from at-risk patients.展开更多
Lithium metal is regarded as the ultimate negative electrode material for secondary batteries due to its high energy density.However,it suffers from poor cycling stability because of its high reactivity with liquid el...Lithium metal is regarded as the ultimate negative electrode material for secondary batteries due to its high energy density.However,it suffers from poor cycling stability because of its high reactivity with liquid electrolytes.Therefore,continuous efforts have been put into improving the cycling Coulombic efficiency(CE)to extend the lifespan of the lithium metal negative electrode.Herein,we report that using dual-salt additives of LiPF_(6) and LiNO_(3) in an ether solvent-based electrolyte can significantly improve the cycling stability and rate capability of a Li-carbon(Li-CNT)composite.As a result,an average cycling CE as high as 99.30% was obtained for the Li-CNT at a current density of 2.5 mA cm^(-2) and an negative electrode to positive electrode capacity(N/P)ratio of 2.The cycling stability and rate capability enhancement of the Li-CNT negative electrode could be attributed to the formation of a better solid electrolyte interphase layer that contains both inorganic components and organic polyether.The former component mainly originates from the decomposition of the LiNO_(3) additive,while the latter comes from the LiPF_(6)-induced ring-opening polymerization of the ether solvent.This novel surface chemistry significantly improves the CE of Li negative electrode,revealing its importance for the practical application of lithium metal batteries.展开更多
Objective: To explore the effect of cytosolic phospholipase A2α(cPLA2α) on hepatocellular carcinoma(HCC) cell adhesion and the underlying mechanisms.Methods: Cell adhesion, detachment, and hanging-drop assays were u...Objective: To explore the effect of cytosolic phospholipase A2α(cPLA2α) on hepatocellular carcinoma(HCC) cell adhesion and the underlying mechanisms.Methods: Cell adhesion, detachment, and hanging-drop assays were utilized to examine the effect of cPLA2α on the cell-matrix and cell-cell adhesion. Downstream substrates and effectors of cPLA2α were screened via a phospho-antibody microarray.Associated signaling pathways were identified by the functional annotation tool DAVID. Candidate proteins were verified using Western blot and colocalization was investigated via immunofluorescence. Western blot and immunohistochemistry were used to detect protein expression in HCC tissues. Prognosis evaluation was conducted using Kaplan-Meier and Cox-proportional hazards regression analyses.Results: Our findings showed that cPLA2α knockdown decreases cell-matrix adhesion but increases cell-cell adhesion in HepG2 cells. Microarray analysis revealed that phosphorylation of multiple proteins at specific sites were regulated by cPLA2α. These phosphorylated proteins were involved in various biological processes. In addition, our results indicated that the focal adhesion pathway was highly enriched in the cPLA2α-relevant signaling pathway. Furthermore, cPLA2α was found to elevate phosphorylation levels of FAK and paxillin, two crucial components of focal adhesion. Moreover, localization of p-FAK to focal adhesions in the plasma membrane was significantly reduced with the downregulation of cPLA2α. Clinically, cPLA2α expression was positively correlated with p-FAK levels. Additionally, high expression of both cPLA2α and p-FAK predicted the worst prognoses for HCC patients.Conclusions: Our study indicated that cPLA2α may promote cell-matrix adhesion via the FAK/paxillin pathway, which partly explains the malignant cPLA2α phenotype seen in HCC.展开更多
P2-type sodium layered oxide cathode (Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)P2-NNMO) has attracted great attention as a promising cathode material for sodium ion batteries because of its high specific capacity. However, this m...P2-type sodium layered oxide cathode (Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)P2-NNMO) has attracted great attention as a promising cathode material for sodium ion batteries because of its high specific capacity. However, this material suffers from a rapid capacity fade during high-voltage cycling. Several mechanisms have been proposed to explain the capacity fade, including intragranular fracture caused by the P2-O2 phase transion, surface structural change, and irreversible lattice oxygen release. Here we systematically investigated the morphological, structural, and chemical changes of P2-NNMO during high-voltage cycling using a variety of characterization techniques. It was found that the lattice distortion and crystal-plane buckling induced by the P2-O2 phase transition slowed down the Na-ion transport in the bulk and hindered the extraction of the Na ions. The sluggish kinetics was the main reason in reducing the accessible capacity while other interfacial degradation mechanisms played minor roles. Our results not only enabled a more complete understanding of the capacity-fading mechanism of P2-NNMO but also revealed the underlying correlations between lattice doping and the moderately improved cycle performance.展开更多
Thermoelectric devices enable direct conversion between thermal and electrical energy.Recent studies have indicated that the thin film/substrate heterostructure is effective in achieving high thermoelectric performanc...Thermoelectric devices enable direct conversion between thermal and electrical energy.Recent studies have indicated that the thin film/substrate heterostructure is effective in achieving high thermoelectric performance via decoupling the Seebeck coefficient and electrical conductivity otherwise adversely inter-dependent in homogenous bulk materials.However,the mechanism underlying the thin film/substrate heterostructure thermoelectricity remains unclear.In addition,the power output of the thin film/substrate heterostructure is limited to the nanowatt scale to date,falling short of the practical application requirement.Here,we fabricated the CrN/SrTiO_(3-x) heterostructures with high thermoelectric output power and outstanding thermal stability.By varying the CrN film thickness and the reduction degree of CrN/SrTiO_(3-x) substrate,the optimized power output and the power density have respectively reached 276μWand 10^(8) mW/cm^(2) for the 30 nm CrN film on a highly reduced surface of CrN/SrTiO_(3-x) under a temperature difference of 300 K.The performance enhancement is attributed to the CrN/CrN/SrTiO_(3-x) heterointerface,corroborated by the band bending as revealed by the scanning Kelvin probe microscopy.These results will stimulate further research efforts towards interface thermoelectrics.展开更多
Ni-rich layered oxide cathode materials,such as LiNi_(0.83)Co_(0.12)Mn_(0.05)O_(2)(NCM811),exhibit high specific capacity and low cost,and become cathode material preference of high-energy-density Li-ion batteries.How...Ni-rich layered oxide cathode materials,such as LiNi_(0.83)Co_(0.12)Mn_(0.05)O_(2)(NCM811),exhibit high specific capacity and low cost,and become cathode material preference of high-energy-density Li-ion batteries.However,these cathode materials are not stable and will form Li-poor reconstructed layers and alkaline compounds(Li_(2)CO_(3),LiOH)on the surface during the storage and processing in humid air,resulting in serious deterioration of electrochemical properties.During the past two decades,the consensus on the surface instability mechanism during humid air storage has not been reached.The main controversy focuses on the unstable octahedron mechanism and the Li/H exchange mechanism.Herein,we investigate the instability mechanism in the humid air by conducting scanning electronic microscopy,scanning transmission electron microscopy,and x-ray photoelectron spectroscopy analysis on NCM811 samples stored in designed atmospheres,etc.,and realize that the surface instability of the NCM811 during storage should be mainly originated from Li/H exchange when it contacts with moisture.展开更多
Estimation method of building damage level was introduced for the accurate and effective estimation of damage extent and relief goods demand according to long-distance image contrast. In order to obtain completion deg...Estimation method of building damage level was introduced for the accurate and effective estimation of damage extent and relief goods demand according to long-distance image contrast. In order to obtain completion degree of building edge extracted from long-distance images before and after disaster, the concentration ratio was analyzed with Hough transformation. Based on the maximum posterior probability, estimation method of affected population was designed to accurately estimate victim population, which can be directly reflected by fugitive population. Moreover, on basis of escape route and fugitive population, demand assignment algorithm by backward calculation was designed to improve rescue efficiency.展开更多
In this paper, we conduct research on the natural image classification and segmentation algorithm based on GPU and neural network. The application of image segmentation is very broad, almost appeared in all areas rela...In this paper, we conduct research on the natural image classification and segmentation algorithm based on GPU and neural network. The application of image segmentation is very broad, almost appeared in all areas related to image processing, and involved in various types. With the fast development of computing technology and integrated circuit technology, the renewal speed of graphics hardware. Our method combines the GPU with network to optimize the traditional image segmentation and classification methods which will be meaningful. In the future, we will focus our attention on the hardware deployment of the GPU to modify the current approach.展开更多
Solid polymer electrolytes(SPEs)based all-solid-state batteries(ASSBs)have attracted extensive attention as a promising candidate for next-generation energy storage systems.Typical ASSBs require high fabrication press...Solid polymer electrolytes(SPEs)based all-solid-state batteries(ASSBs)have attracted extensive attention as a promising candidate for next-generation energy storage systems.Typical ASSBs require high fabrication pressure to achieve high areal capacity,under which,however,SPEs struggle and risk damage or failure due to their low mechanical strength.There is also a lack of study on complex stress and strain SPEs experience during ASSB cell assembly processes.Here,ceramic solid electrolytes are selected as interlayers to address the stress-strain conditions during assembling.As a result,high areal capacity ASSBs with a LiCoO2 loading of 12 mg·cm^(-2) were assembled with SPE-based composite electrolytes.Around 200 cycles were carried out for these cells at a current density of 1 mA·cm^(-2) under room temperature.The capacity decay of the battery at 200 cycles is observed to be as low as 0.06% per cycle.This work identifies a critical issue for application of SPEs in ASSBs and provides a potential strategy for the design of SPE-based ASSBs with high specific energy and long cycle life.展开更多
Comprehensive Summary Lithium(Li)metal is considered ideal for high-energy-density batteries due to its extremely high specific capacity and low electrochemical potential.However,uncontrolled Li dendrite growth and in...Comprehensive Summary Lithium(Li)metal is considered ideal for high-energy-density batteries due to its extremely high specific capacity and low electrochemical potential.However,uncontrolled Li dendrite growth and interfacial instability during repeated Li plating/stripping have limited the practical applicability of Li metal batteries(LMBs).Over the past decades,substantial efforts have been devoted to solving the challenges associated with Li metal anodes.Our research team has developed several Li-carbon(Li-C)microsphere composites in recent years to suppress the formation of Li dendrites and achieve a decent cycle life.In this account,we summarize our advances in the design and application of Li-C composites,which include the developments in the structure and chemical composition of high-specific-capacity Li-C composites,strategies for surface passivation of the micro-spherical Li-C composites,and applications of the Li-C composite in next-generation high-energy-density Li-ion,Li-air,and solid-state LMBs.Finally,we discuss future perspectives for developing high-performance Li metal anodes and endeavors to realize the practical applications of LMBs.展开更多
As one of the most promising cathodes for sodium-ion batteries(SIBs),the layered transition metal oxides have attracted great attentions due to their high specific capacities and facile synthesis.However,their applica...As one of the most promising cathodes for sodium-ion batteries(SIBs),the layered transition metal oxides have attracted great attentions due to their high specific capacities and facile synthesis.However,their applications are still hindered by the problems of poor moisture stability and sluggish Na^(+)diffusion caused by intrinsic structural Jahn–Teller distortion.Herein,we demonstrate a new approach to settle the above issues through introducing K^(+)into the structures of Ni/Mn-based materials.The physicochemical characterizations reveal that K^(+)induces atomic surface reorganization to form the birnessite-type K_(2)Mn_(4)O_(8).Combining with the phosphate,the mixed coating layer protects the cathodes from moisture and hinders metal dissolution into the electrolyte effectively.Simultaneously,K^(+)substitution at Na site in the bulk structure can not only widen the lattice-spacing for favoring Na^(+)diffusion,but also work as the rivet to restrain the grain crack upon cycling.The as achieved K^(+)-decorated P2-Na_(0.67)Mn_(0.75)Ni_(0.2)5O_(2)(NKMNO@KM/KP)cathodes are tested in both coin cell and pouch cell configurations using Na metal or hard carbon(HC)as anodes.Impressively,the NKMNO@KM/KP||Na half-cell demonstrates a high rate performance of 50 C and outstanding cycling performance of 90.1%capacity retention after 100 cycles at 5 C.Furthermore,the NKMNO@KM/KP||HC fullcell performed a promising energy density of 213.9 Wh·kg^(−1).This performance significantly outperforms most reported state-ofthe-art values.Additionally,by adopting this strategy on O3-NaMn_(0.5)Ni_(0.5)O_(2),we further proved the universality of this method on layered cathodes for SIBs.展开更多
As a ubiquitous natural phenomenon,ice/frost formation on solid surfaces have adverse effects on many commercial and residential activities.Icephobic surfaces feature low ice adhesion strengths(<100 kPa)can passive...As a ubiquitous natural phenomenon,ice/frost formation on solid surfaces have adverse effects on many commercial and residential activities.Icephobic surfaces feature low ice adhesion strengths(<100 kPa)can passively retard ice formation and ease ice removal.Superhydrophobic surfaces and liquid-lubricating surfaces are two prevailing categories of icephobic surfaces.However,their long-term stability is relatively poor,and the ice adhesion strengths are not low enough for passive removal of small ice crystals(e.g.,frosts)from the surfaces.Herein,we combine the superhydrophobic and liquid-like properties in one surface to obtain durable icephobic surfaces with extremely low ice adhesion strengths(about 0.035 kPa).Ices and frosts can be removed from the surface under the action of gravity or gas purge.These surfaces are prepared based on surface nanoconical structure and covalently-grafted liquid-like perfluorinated polyether(PFPE)coating,which show synergy effects on suppressing icing and frosting by promoting expulsion of subcooled condensate droplets from the nanotexture and decreasing ice adhesion strengths.The icephobic surfaces show significantly better durability compared to lubricant-impregnated textured surfaces.Our results provide a new avenue to design passive anti-icing/anti-frosting surfaces for a wide range of applications where surfaces are exposed to humid and low-temperature environments.展开更多
The development of high-performance solid-state electrolyte(SSE)films is critical to the practical application of all-solid-state Li metal batteries(ASSLMBs).However,developing high-performance free-standing electroly...The development of high-performance solid-state electrolyte(SSE)films is critical to the practical application of all-solid-state Li metal batteries(ASSLMBs).However,developing high-performance free-standing electrolyte films remains a challenging task.In this work,we demonstrate a novel scalable solvent-free process for fabricating high ceramic content composite solid-state electrolyte(HCCSE)films.Specifically speaking,a mixture of ceramic and polymer is dry mixed,fibered,and calendered into a free-standing porous ceramic film,on which polymer precursor is coated and polymerized to bridge the inorganic ceramic particles,resulting in a flexible HCCSE film with a ceramic content of up to 80 wt.%.High ceramic content not only leads to high ionic conductivity but also brings good mechanical properties;while the organic phase enables electrode|electrolyte interfacial stability.When Li_(10)GeP_(2)S_(12)(LGPS)and polymeric ionic liquid-based solid polymer electrolytes(PIL-SPEs)were used as the inorganic and organic phases,respectively,the room temperature ionic conductivity of the resulted HCCSE reaches 0.91 mS·cm−1.Based on this HCCSE,Li||Li symmetric battery cycled stably for more than 2,400 h with ultra-low overpotential,and ASSLMBs with different cathodes(LiFePO4 and sulfurized polyacrylonitrile(PAN-S))present small polarization and decent cyclability at room temperature.This work provides a novel scalable solvent-free strategy for preparing high-performance freestanding composite solid-state electrolyte(CSE)film for room temperature ASSLMBs.展开更多
The self-assembly of DNA provides an attractive approach to understanding structural formation mechanism in living organisms and to assisting applications in materials chemistry.Herein,we investigated the effect of me...The self-assembly of DNA provides an attractive approach to understanding structural formation mechanism in living organisms and to assisting applications in materials chemistry.Herein,we investigated the effect of metal ions on chiral self-assembly of DNA through the synthesis of chiral mesostructured silica via self-assembly of metal ions,DNA,and silica source.31 types of multivalent cationic metal ions were found to induce formation of chiral impeller-like DNA-silica complexes due to the chiral stacking of DNA.The strength of the interaction between the metal ion and phosphate group of DNA was speculated for the chiral stacking of DNA due to close distance of adjacent DNA to assure mutual recognition.Theoretical calculations indicated that chiral packing of DNA depends on the stability of the bridging phosphate-metal ion-phosphate bonds of DNA based on electron delocalization in d-orbital conjugation of metal ions.展开更多
1.Background.Polymethyl methacrylate(PMMA)bone cement has been widely used in orthopedic clinics for over 70 years.In 1952 and 1953,Kiaer and Haboush reported their work on the use of PMMA cement to achieve bone adher...1.Background.Polymethyl methacrylate(PMMA)bone cement has been widely used in orthopedic clinics for over 70 years.In 1952 and 1953,Kiaer and Haboush reported their work on the use of PMMA cement to achieve bone adherence to prostheses in femoral head replacement[1,2],.In 1987,Galibert et al.first reported the use of PMMA cement in spinal surgery for vertebroplasty(PVP)to treat vertebral hemangiomas[3].By 2002,approximately 38,000 vertebroplasties and 16,000 kyphoplasties were performed in the United States[4].展开更多
Organic-based electrode materials for lithium-ion batteries (LIBs) are promising due to their high theoretical capacity,structure versatility and environmental benignity.However,the poor intrinsic electric conductivit...Organic-based electrode materials for lithium-ion batteries (LIBs) are promising due to their high theoretical capacity,structure versatility and environmental benignity.However,the poor intrinsic electric conductivity of most polymers results in slow reaction kinetics and hinders their application as electrode materials for LIBs.A binder-free self-supporting organic electrode with excellent redox kinetics is herein demonstrated via in situ polymerization of a uniform thin polyimide (PI) layer on a porous and highly conductive carbonized nanofiber (CNF) framework.The PI active material in the porous PI@CNF film has large physical contact area with both the CNF and the electrolyte thus obtains superior electronic and ionic conduction.As a result,the PI@CNF cathode exhibits a discharge capacity of 170 mAh·g^-1 at 1 C (175 mA·g^-1),remarkable rate-performance (70.5% of 0.5 C capacity can be obtained at a 100 C discharge rate),and superior cycling stability with 81.3% capacity retention after 1,000 cycles at 1 C.Last but not least,a four-electron transfer redox process of the PI polymer was realized for the first time thanks to the excellent redox kinetics of the PI@CNF electrode,showing a discharge capacity exceeding 300 mAh·g^-1 at a current of 175 mA·g^-1.展开更多
Lamellar compounds such as the disulfides of molybdenum and tungsten are widely used as additives in lubricant oils or as solid lubricants in aerospace industries.The dioxides of these two transition metals have ident...Lamellar compounds such as the disulfides of molybdenum and tungsten are widely used as additives in lubricant oils or as solid lubricants in aerospace industries.The dioxides of these two transition metals have identical microstructures with those of the disulfides.The differences in the lubrication behaviors of disulfide and dioxides were investigated theoretically.Tungsten dioxide and molybdenum dioxide exhibit higher bond strengths at the interface and lower interlayer interactions than those of the disulfides which indicates their superlubricity.Furthermore,the topography of the electron density of the single layer nanostructure determined their sliding potential barrier;the dioxides showed a weaker electronic cloud distribution between the two neighboring oxygen atoms,which facilitated the oxygen atoms of the counterpart to go through.For commensurate friction,the dioxides exhibited nearly the same value of friction work,and same was the case for the disulfides.The lower positive value of friction work for the dioxides confirmed their improved lubricity than the disulfides and the higher mechanical strength of the bulk dioxides demonstrated that they are excellent solid lubricants in vacuum.展开更多
基金We acknowledge the support from the National Natural Science Foundation of China(21991153,21991150).
文摘Electrochemical reduction of CO_(2)(CO_(2)RR)coupled with renewable electrical energy is an attractive way of upgrading CO_(2)to value-added chemicals and closing the carbon cycle.However,CO_(2)RR electrocatalysts still suffer from high overpotential,and the complex reaction pathways of CO_(2)RR often lead to mixed products.Early research focuses on tuning the binding of reaction intermediates on electrocatalysts,and recent efforts have revealed that the design of electrolysis reactors is equally important for efficient and selective CO_(2)RR.In this review,we present an overview of recent advances and challenges toward achieving high activity and high selectivity in CO_(2)RR at ambient conditions,with a particular focus on the progress of CO_(2)RR electrocatalyst engineering and reactor design.Our discussion begins with three types of electrocatalysts for CO_(2)RR(noble metalbased,none-noble metal-based,and metal-free electrocatalysts),and then we examine systems-level strategies toward engineering specific components of the electrolyzer,including gas diffusion electrodes,electrolytes,and polymer electrolyte membranes.We close with future perspectives on catalyst development,in-situ/operando characterization,and electrolyzer performance evaluation in CO_(2)RR studies.
基金supported by the National Natural Science Foundation of China(NSFC,No.21203220 and 21133011)China Postdoctoral Science Foundation(No.2014M551674)+1 种基金Jiangsu Planned Projects for Postdoctoral Research Funds(No.1302070C)the National Basic Research Program of China(973 Program,No.2011CB201404)
文摘The chemical equilibrium and reaction kinetic behavior in the synthesis of polyoxymethylene dimethyl ethers (DMMn) were investigated over sulfated titania in order to reveal the decisive factor controlling the reaction. The results showed that the molar ratio of adjacent DMMn products in equilibrium solution had the same value, which depended absolutely on the reaction temperature. Meanwhile, the reactions had the same DMMn products distributions under varied reaction conditions. The equilibrium constants of the related step-wise reactions for DMMn formation were equal, which were calculated based on the bulk compositions of the reaction solution. And thus, the selectivity to DMMn was mainly controlled by the chemical equilibrium, i.e., thermodynamic control. In brief, the present results provide some guidance for future synthesis of DMMn.
基金supported by the National Natural Science Foundation of China(Grant Nos.81972656 and 31671421)the Key Project of Tianjin Natural Science Foundation(Grant No.18JCZDJC35200)+1 种基金the State Key Project on Infectious Diseases of China(Grant No.2018ZX10723204)the National 135 Major Project of China(2018ZX10302205)。
文摘Objective:Hepatocellular carcinoma(HCC)is a lethal global disease that requires an accurate diagnosis.We assessed the potential of 5 serum biomarkers(AFP,AFU,GGT-II,GPC3,and HGF)in the diagnosis of HCC.Methods:In this retrospective study,we measured the serum levels of each biomarker using ELISAs in 921 participants,including 298 patients with HCC,154 patients with chronic hepatitis(CH),122 patients with liver cirrhosis(LC),and 347 healthy controls from 3 hospitals.Patients negative for hepatitis B surface antigen and hepatitis C antibody(called"NBNC-HCC")and patients positive for the above indices(called"HBV-HCC and HCV-HCC")were enrolled.The selected diagnostic model was constructed using a training cohort(n=468),and a validation cohort(n=453)was used to validate our results.Receiver operating characteristic analysis was used to evaluate the diagnostic accuracy.Results:Theα-L-fucosidase(AFU)/α-fetoprotein(AFP)combination was best able to distinguish NBNC-HCC[area under the curve:0.986(95%confidence interval:0.958–0.997),sensitivity:92.6%,specificity:98.9%]from healthy controls in the test cohort.For screening populations at risk of developing HCC(CH and LC),the AFP/AFU combination improved the diagnostic specificity for early-stage HCC[area under the curve:0.776(0.712–0.831),sensitivity:52.5%,specificity:91.6%in the test group].In all-stage HBV-HCC and HCV-HCC,AFU was also the best candidate biomarker combined with AFP[area under the curve:0.835(0.784–0.877),sensitivity 69.1%,specificity:87.4%in the test group].All results were verified in the validation group.Conclusions:The AFP/AFU combination could be used to identify NBNC-HCC from healthy controls and hepatitis-related HCC from at-risk patients.
基金the National Natural Science Foundation of China(Grant nos.21625304 and 21733012)the Ministry of Science and Technology(Grant No.2016YFA0200703).
文摘Lithium metal is regarded as the ultimate negative electrode material for secondary batteries due to its high energy density.However,it suffers from poor cycling stability because of its high reactivity with liquid electrolytes.Therefore,continuous efforts have been put into improving the cycling Coulombic efficiency(CE)to extend the lifespan of the lithium metal negative electrode.Herein,we report that using dual-salt additives of LiPF_(6) and LiNO_(3) in an ether solvent-based electrolyte can significantly improve the cycling stability and rate capability of a Li-carbon(Li-CNT)composite.As a result,an average cycling CE as high as 99.30% was obtained for the Li-CNT at a current density of 2.5 mA cm^(-2) and an negative electrode to positive electrode capacity(N/P)ratio of 2.The cycling stability and rate capability enhancement of the Li-CNT negative electrode could be attributed to the formation of a better solid electrolyte interphase layer that contains both inorganic components and organic polyether.The former component mainly originates from the decomposition of the LiNO_(3) additive,while the latter comes from the LiPF_(6)-induced ring-opening polymerization of the ether solvent.This novel surface chemistry significantly improves the CE of Li negative electrode,revealing its importance for the practical application of lithium metal batteries.
基金supported by grants from Key Project of Tianjin Natural Science Foundation (Grant No.18JCZDJC35200)NSFC-FRQS program (Grant No.81661128009)+1 种基金The Science & Technology Development Fund of Tianjin Education Commission for Higher Education (Grant No.2017KJ202)Scientific Research Foundation for Returned Scholars and Doctoral Program of Tianjin Medical University Cancer Institute and Hospital (Grant No.B1703)
文摘Objective: To explore the effect of cytosolic phospholipase A2α(cPLA2α) on hepatocellular carcinoma(HCC) cell adhesion and the underlying mechanisms.Methods: Cell adhesion, detachment, and hanging-drop assays were utilized to examine the effect of cPLA2α on the cell-matrix and cell-cell adhesion. Downstream substrates and effectors of cPLA2α were screened via a phospho-antibody microarray.Associated signaling pathways were identified by the functional annotation tool DAVID. Candidate proteins were verified using Western blot and colocalization was investigated via immunofluorescence. Western blot and immunohistochemistry were used to detect protein expression in HCC tissues. Prognosis evaluation was conducted using Kaplan-Meier and Cox-proportional hazards regression analyses.Results: Our findings showed that cPLA2α knockdown decreases cell-matrix adhesion but increases cell-cell adhesion in HepG2 cells. Microarray analysis revealed that phosphorylation of multiple proteins at specific sites were regulated by cPLA2α. These phosphorylated proteins were involved in various biological processes. In addition, our results indicated that the focal adhesion pathway was highly enriched in the cPLA2α-relevant signaling pathway. Furthermore, cPLA2α was found to elevate phosphorylation levels of FAK and paxillin, two crucial components of focal adhesion. Moreover, localization of p-FAK to focal adhesions in the plasma membrane was significantly reduced with the downregulation of cPLA2α. Clinically, cPLA2α expression was positively correlated with p-FAK levels. Additionally, high expression of both cPLA2α and p-FAK predicted the worst prognoses for HCC patients.Conclusions: Our study indicated that cPLA2α may promote cell-matrix adhesion via the FAK/paxillin pathway, which partly explains the malignant cPLA2α phenotype seen in HCC.
基金financial support from the National Natural Science Foundation of China (21938005, 21573147, 22005190, 22008154, 21872163)the Science & Technology Commission of Shanghai Municipality, the Natural Science Foundation of Shanghai (19DZ1205500, 19ZR1424600, 19ZR1475100)the Sichuan Science and Technology Program (2021JDRC0015 to L.S.L)。
文摘P2-type sodium layered oxide cathode (Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)P2-NNMO) has attracted great attention as a promising cathode material for sodium ion batteries because of its high specific capacity. However, this material suffers from a rapid capacity fade during high-voltage cycling. Several mechanisms have been proposed to explain the capacity fade, including intragranular fracture caused by the P2-O2 phase transion, surface structural change, and irreversible lattice oxygen release. Here we systematically investigated the morphological, structural, and chemical changes of P2-NNMO during high-voltage cycling using a variety of characterization techniques. It was found that the lattice distortion and crystal-plane buckling induced by the P2-O2 phase transition slowed down the Na-ion transport in the bulk and hindered the extraction of the Na ions. The sluggish kinetics was the main reason in reducing the accessible capacity while other interfacial degradation mechanisms played minor roles. Our results not only enabled a more complete understanding of the capacity-fading mechanism of P2-NNMO but also revealed the underlying correlations between lattice doping and the moderately improved cycle performance.
基金supported by Liaoning Revitalization Talents Program (No. XLYC1807209)Dalian Institute of Chemical Physics (DICP I202037)the National Natural Science Foundation of China (Grant Nos. 21625304, 22022205).
文摘Thermoelectric devices enable direct conversion between thermal and electrical energy.Recent studies have indicated that the thin film/substrate heterostructure is effective in achieving high thermoelectric performance via decoupling the Seebeck coefficient and electrical conductivity otherwise adversely inter-dependent in homogenous bulk materials.However,the mechanism underlying the thin film/substrate heterostructure thermoelectricity remains unclear.In addition,the power output of the thin film/substrate heterostructure is limited to the nanowatt scale to date,falling short of the practical application requirement.Here,we fabricated the CrN/SrTiO_(3-x) heterostructures with high thermoelectric output power and outstanding thermal stability.By varying the CrN film thickness and the reduction degree of CrN/SrTiO_(3-x) substrate,the optimized power output and the power density have respectively reached 276μWand 10^(8) mW/cm^(2) for the 30 nm CrN film on a highly reduced surface of CrN/SrTiO_(3-x) under a temperature difference of 300 K.The performance enhancement is attributed to the CrN/CrN/SrTiO_(3-x) heterointerface,corroborated by the band bending as revealed by the scanning Kelvin probe microscopy.These results will stimulate further research efforts towards interface thermoelectrics.
文摘Ni-rich layered oxide cathode materials,such as LiNi_(0.83)Co_(0.12)Mn_(0.05)O_(2)(NCM811),exhibit high specific capacity and low cost,and become cathode material preference of high-energy-density Li-ion batteries.However,these cathode materials are not stable and will form Li-poor reconstructed layers and alkaline compounds(Li_(2)CO_(3),LiOH)on the surface during the storage and processing in humid air,resulting in serious deterioration of electrochemical properties.During the past two decades,the consensus on the surface instability mechanism during humid air storage has not been reached.The main controversy focuses on the unstable octahedron mechanism and the Li/H exchange mechanism.Herein,we investigate the instability mechanism in the humid air by conducting scanning electronic microscopy,scanning transmission electron microscopy,and x-ray photoelectron spectroscopy analysis on NCM811 samples stored in designed atmospheres,etc.,and realize that the surface instability of the NCM811 during storage should be mainly originated from Li/H exchange when it contacts with moisture.
文摘Estimation method of building damage level was introduced for the accurate and effective estimation of damage extent and relief goods demand according to long-distance image contrast. In order to obtain completion degree of building edge extracted from long-distance images before and after disaster, the concentration ratio was analyzed with Hough transformation. Based on the maximum posterior probability, estimation method of affected population was designed to accurately estimate victim population, which can be directly reflected by fugitive population. Moreover, on basis of escape route and fugitive population, demand assignment algorithm by backward calculation was designed to improve rescue efficiency.
文摘In this paper, we conduct research on the natural image classification and segmentation algorithm based on GPU and neural network. The application of image segmentation is very broad, almost appeared in all areas related to image processing, and involved in various types. With the fast development of computing technology and integrated circuit technology, the renewal speed of graphics hardware. Our method combines the GPU with network to optimize the traditional image segmentation and classification methods which will be meaningful. In the future, we will focus our attention on the hardware deployment of the GPU to modify the current approach.
基金the National Key R&D Program of China(No.2021YFB3800300)Science and Technology Commission of Shanghai Municipality(No.23DZ1200800)China Postdoctoral Science Foundation(Nos.BX20220199 and 2023M732208).
文摘Solid polymer electrolytes(SPEs)based all-solid-state batteries(ASSBs)have attracted extensive attention as a promising candidate for next-generation energy storage systems.Typical ASSBs require high fabrication pressure to achieve high areal capacity,under which,however,SPEs struggle and risk damage or failure due to their low mechanical strength.There is also a lack of study on complex stress and strain SPEs experience during ASSB cell assembly processes.Here,ceramic solid electrolytes are selected as interlayers to address the stress-strain conditions during assembling.As a result,high areal capacity ASSBs with a LiCoO2 loading of 12 mg·cm^(-2) were assembled with SPE-based composite electrolytes.Around 200 cycles were carried out for these cells at a current density of 1 mA·cm^(-2) under room temperature.The capacity decay of the battery at 200 cycles is observed to be as low as 0.06% per cycle.This work identifies a critical issue for application of SPEs in ASSBs and provides a potential strategy for the design of SPE-based ASSBs with high specific energy and long cycle life.
基金support was provided by the National Natural Science Foundation of China(Grant nos.21733012 and 22179143)National Key R&D Program of China(2021YFB3800300).
文摘Comprehensive Summary Lithium(Li)metal is considered ideal for high-energy-density batteries due to its extremely high specific capacity and low electrochemical potential.However,uncontrolled Li dendrite growth and interfacial instability during repeated Li plating/stripping have limited the practical applicability of Li metal batteries(LMBs).Over the past decades,substantial efforts have been devoted to solving the challenges associated with Li metal anodes.Our research team has developed several Li-carbon(Li-C)microsphere composites in recent years to suppress the formation of Li dendrites and achieve a decent cycle life.In this account,we summarize our advances in the design and application of Li-C composites,which include the developments in the structure and chemical composition of high-specific-capacity Li-C composites,strategies for surface passivation of the micro-spherical Li-C composites,and applications of the Li-C composite in next-generation high-energy-density Li-ion,Li-air,and solid-state LMBs.Finally,we discuss future perspectives for developing high-performance Li metal anodes and endeavors to realize the practical applications of LMBs.
基金the National Natural Science Foundation of China(Nos.52271222,51971146,51971147,52171218,22005190,and 21938005)We also acknowledge the supports of Shanghai Outstanding Academic Leaders Plan,the Innovation Program of Shanghai Municipal Education Commission(No.2019-01-07-00-07-E00015)+4 种基金Shanghai Pujiang Program(No.21PJ1411100)Shanghai Rising-Star Program(Nos.20QA1407100 and 21QA1406500)the Shanghai Science and Technology Commission(Nos.21010503100,20ZR1438400 and 22ZR1443900)Zhejiang Provincial Natural Science Foundation of China(No.LGG22F010017)the Key R&D Program of Zhejiang Province(Nos.2019C01155 and 2020C01128).
文摘As one of the most promising cathodes for sodium-ion batteries(SIBs),the layered transition metal oxides have attracted great attentions due to their high specific capacities and facile synthesis.However,their applications are still hindered by the problems of poor moisture stability and sluggish Na^(+)diffusion caused by intrinsic structural Jahn–Teller distortion.Herein,we demonstrate a new approach to settle the above issues through introducing K^(+)into the structures of Ni/Mn-based materials.The physicochemical characterizations reveal that K^(+)induces atomic surface reorganization to form the birnessite-type K_(2)Mn_(4)O_(8).Combining with the phosphate,the mixed coating layer protects the cathodes from moisture and hinders metal dissolution into the electrolyte effectively.Simultaneously,K^(+)substitution at Na site in the bulk structure can not only widen the lattice-spacing for favoring Na^(+)diffusion,but also work as the rivet to restrain the grain crack upon cycling.The as achieved K^(+)-decorated P2-Na_(0.67)Mn_(0.75)Ni_(0.2)5O_(2)(NKMNO@KM/KP)cathodes are tested in both coin cell and pouch cell configurations using Na metal or hard carbon(HC)as anodes.Impressively,the NKMNO@KM/KP||Na half-cell demonstrates a high rate performance of 50 C and outstanding cycling performance of 90.1%capacity retention after 100 cycles at 5 C.Furthermore,the NKMNO@KM/KP||HC fullcell performed a promising energy density of 213.9 Wh·kg^(−1).This performance significantly outperforms most reported state-ofthe-art values.Additionally,by adopting this strategy on O3-NaMn_(0.5)Ni_(0.5)O_(2),we further proved the universality of this method on layered cathodes for SIBs.
基金We acknowledge the financial support from National Natural Science Foundation of China(Nos.22072185,12072381,21872176,and 21805315)Pearl River Talents Program(No.2017GC010671),Natural Science Foundation of Guangdong Province(No.2019A1515012030)Science and Technology Innovation Project of Guangzhou(No.202102020263).
文摘As a ubiquitous natural phenomenon,ice/frost formation on solid surfaces have adverse effects on many commercial and residential activities.Icephobic surfaces feature low ice adhesion strengths(<100 kPa)can passively retard ice formation and ease ice removal.Superhydrophobic surfaces and liquid-lubricating surfaces are two prevailing categories of icephobic surfaces.However,their long-term stability is relatively poor,and the ice adhesion strengths are not low enough for passive removal of small ice crystals(e.g.,frosts)from the surfaces.Herein,we combine the superhydrophobic and liquid-like properties in one surface to obtain durable icephobic surfaces with extremely low ice adhesion strengths(about 0.035 kPa).Ices and frosts can be removed from the surface under the action of gravity or gas purge.These surfaces are prepared based on surface nanoconical structure and covalently-grafted liquid-like perfluorinated polyether(PFPE)coating,which show synergy effects on suppressing icing and frosting by promoting expulsion of subcooled condensate droplets from the nanotexture and decreasing ice adhesion strengths.The icephobic surfaces show significantly better durability compared to lubricant-impregnated textured surfaces.Our results provide a new avenue to design passive anti-icing/anti-frosting surfaces for a wide range of applications where surfaces are exposed to humid and low-temperature environments.
基金supported by the National Natural Science Foundation of China(Nos.21733012 and 22179143)the National Key R&D Program of China(No.2021YFB3800300).
文摘The development of high-performance solid-state electrolyte(SSE)films is critical to the practical application of all-solid-state Li metal batteries(ASSLMBs).However,developing high-performance free-standing electrolyte films remains a challenging task.In this work,we demonstrate a novel scalable solvent-free process for fabricating high ceramic content composite solid-state electrolyte(HCCSE)films.Specifically speaking,a mixture of ceramic and polymer is dry mixed,fibered,and calendered into a free-standing porous ceramic film,on which polymer precursor is coated and polymerized to bridge the inorganic ceramic particles,resulting in a flexible HCCSE film with a ceramic content of up to 80 wt.%.High ceramic content not only leads to high ionic conductivity but also brings good mechanical properties;while the organic phase enables electrode|electrolyte interfacial stability.When Li_(10)GeP_(2)S_(12)(LGPS)and polymeric ionic liquid-based solid polymer electrolytes(PIL-SPEs)were used as the inorganic and organic phases,respectively,the room temperature ionic conductivity of the resulted HCCSE reaches 0.91 mS·cm−1.Based on this HCCSE,Li||Li symmetric battery cycled stably for more than 2,400 h with ultra-low overpotential,and ASSLMBs with different cathodes(LiFePO4 and sulfurized polyacrylonitrile(PAN-S))present small polarization and decent cyclability at room temperature.This work provides a novel scalable solvent-free strategy for preparing high-performance freestanding composite solid-state electrolyte(CSE)film for room temperature ASSLMBs.
基金supported by the National Key Research and Development Program of China(No.2021YFA1200300,S.C.,2021YFA1500300,X.L.)the National Natural Science Foundation of China(No.21931008,S.C.,22072090 X.L,21991153 L.C.)the science foundation of the Shanghai Municipal science and Technology Commission(No.19JC1410300,S.C.).
文摘The self-assembly of DNA provides an attractive approach to understanding structural formation mechanism in living organisms and to assisting applications in materials chemistry.Herein,we investigated the effect of metal ions on chiral self-assembly of DNA through the synthesis of chiral mesostructured silica via self-assembly of metal ions,DNA,and silica source.31 types of multivalent cationic metal ions were found to induce formation of chiral impeller-like DNA-silica complexes due to the chiral stacking of DNA.The strength of the interaction between the metal ion and phosphate group of DNA was speculated for the chiral stacking of DNA due to close distance of adjacent DNA to assure mutual recognition.Theoretical calculations indicated that chiral packing of DNA depends on the stability of the bridging phosphate-metal ion-phosphate bonds of DNA based on electron delocalization in d-orbital conjugation of metal ions.
基金supported by the National Natural Science Foundation of China(No.82272165)the Shanghai Committee of Science and Technology(No.20ZR1451800)+1 种基金the Municipal Health Commission Fundation of Shanghai(No.202040141)the Outstanding Youth Foundation Project of Tongren(No.2020SHTRYC02)。
文摘1.Background.Polymethyl methacrylate(PMMA)bone cement has been widely used in orthopedic clinics for over 70 years.In 1952 and 1953,Kiaer and Haboush reported their work on the use of PMMA cement to achieve bone adherence to prostheses in femoral head replacement[1,2],.In 1987,Galibert et al.first reported the use of PMMA cement in spinal surgery for vertebroplasty(PVP)to treat vertebral hemangiomas[3].By 2002,approximately 38,000 vertebroplasties and 16,000 kyphoplasties were performed in the United States[4].
基金the "Strategic Priority Research Program:of the CAS (No.XDA09010600)the National Natural Science Foundation of China (Nos.21473242,21625304 and 21733012).
文摘Organic-based electrode materials for lithium-ion batteries (LIBs) are promising due to their high theoretical capacity,structure versatility and environmental benignity.However,the poor intrinsic electric conductivity of most polymers results in slow reaction kinetics and hinders their application as electrode materials for LIBs.A binder-free self-supporting organic electrode with excellent redox kinetics is herein demonstrated via in situ polymerization of a uniform thin polyimide (PI) layer on a porous and highly conductive carbonized nanofiber (CNF) framework.The PI active material in the porous PI@CNF film has large physical contact area with both the CNF and the electrolyte thus obtains superior electronic and ionic conduction.As a result,the PI@CNF cathode exhibits a discharge capacity of 170 mAh·g^-1 at 1 C (175 mA·g^-1),remarkable rate-performance (70.5% of 0.5 C capacity can be obtained at a 100 C discharge rate),and superior cycling stability with 81.3% capacity retention after 1,000 cycles at 1 C.Last but not least,a four-electron transfer redox process of the PI polymer was realized for the first time thanks to the excellent redox kinetics of the PI@CNF electrode,showing a discharge capacity exceeding 300 mAh·g^-1 at a current of 175 mA·g^-1.
基金the National Nature Science Foundation of China,the 'Top Hundred Talents' Program of Chinese Academy of Sciences and the National Key Basic Research and Development (973) Program of China (2013CB632300) for financial support
文摘Lamellar compounds such as the disulfides of molybdenum and tungsten are widely used as additives in lubricant oils or as solid lubricants in aerospace industries.The dioxides of these two transition metals have identical microstructures with those of the disulfides.The differences in the lubrication behaviors of disulfide and dioxides were investigated theoretically.Tungsten dioxide and molybdenum dioxide exhibit higher bond strengths at the interface and lower interlayer interactions than those of the disulfides which indicates their superlubricity.Furthermore,the topography of the electron density of the single layer nanostructure determined their sliding potential barrier;the dioxides showed a weaker electronic cloud distribution between the two neighboring oxygen atoms,which facilitated the oxygen atoms of the counterpart to go through.For commensurate friction,the dioxides exhibited nearly the same value of friction work,and same was the case for the disulfides.The lower positive value of friction work for the dioxides confirmed their improved lubricity than the disulfides and the higher mechanical strength of the bulk dioxides demonstrated that they are excellent solid lubricants in vacuum.