Decays of charmonium into hyperon and antihyperon pairs provide a pristine laboratory for exploring hyperon properties,such as their polarization and decay parameters,and for conducting tests of fundamental symmetries...Decays of charmonium into hyperon and antihyperon pairs provide a pristine laboratory for exploring hyperon properties,such as their polarization and decay parameters,and for conducting tests of fundamental symmetries.This brief review highlights the significant progress made in precise tests of CP symmetry at BESIII using entangled hyperon-antihyperon pairs。展开更多
Heterogeneous solid frustrated-Lewis-pair(FLP)catalyst is of great promise in practical hydrogenation applications.It has been found that all-solid FLPs can be created on ceria via surface oxygen vacancy regulation.Co...Heterogeneous solid frustrated-Lewis-pair(FLP)catalyst is of great promise in practical hydrogenation applications.It has been found that all-solid FLPs can be created on ceria via surface oxygen vacancy regulation.Consequently,it is desired to investigate the mechanisms of the FLP-catalyzed hydrogenation of C=C and C=O and provide insight into the modification of CeO_(2)catalysts for the selective hydrogenation.In this work,the reaction mechanism of the hydrogenation of CH_(2)=CH_(2)and CH_(3)CH=O at the FLP sites constructed on CeO_(2)(110)surface was investigated by density functional theory(DFT),with the classical Lewis acid-base pairs(CLP)site as the reference.The results illustrate that at the CLP site,the dissociated hydride(H^(δ−))forms a stable H−O bond with the surface O atom,while at the FLP site,H^(δ−)is stabilized by Ce,displaying higher activity on the one hand.On the other hand,the electron cloud density of the Ce atom at the FLP site is higher,which can transfer more electrons to the adsorbed C_(C=C)and O_(C=O)atoms,leading to a higher degree of activation for C=C and C=O bonds,as indicated by the Bader charge analysis.Therefore,compared to the CLP site,the FLP site exhibits higher hydrogenation activity for CH_(2)=CH_(2)and CH_(3)CH=O.Furthermore,at the FLP sites,it demonstrates high efficiency in catalyzing the hydrogenation of CH_(2)=CH_(2)with the rate-determining barrier of 1.04 eV,but it shows limited activity for the hydrogenation of CH_(3)CH=O with the rate-determining barrier of 1.94 eV.It means that the selective hydrogenation of C=C can be effectively achieved at the FLP sites concerning selective hydrogenation catalysis.The insights shown in this work help to clarify the reaction mechanism of the hydrogenation of C=C and C=O at FLP site on CeO_(2)(110)and reveal the relationship between the catalytic performance and the nature of the active site,which is of great benefit to development of rational design of heterogeneous FLP catalysts.展开更多
The development of solid frustrated Lewis pairs(FLPs)catalysts with porous structures is a promising strategy for advancing green hydrogenation technologies and has garnered significant attention.Leveraging the divers...The development of solid frustrated Lewis pairs(FLPs)catalysts with porous structures is a promising strategy for advancing green hydrogenation technologies and has garnered significant attention.Leveraging the diverse oxidation states and structural tunability of cerium-based metal-organic frameworks(Ce-MOFs),this study employed a competitive coordination strategy utilizing a single carboxylate functional group ligand to construct a series of MOF-808-X(X=-NH_(2),-OH,-Br,and-NO_(2))featuring rich solid-state FLPs for hydrogenation of unsaturated olefins.The-X functional group serves as a microenvironment,enhancing hydrogenation activity by modulating the electronic properties and acid-base characteristics of the FLP sites.The unique redox properties of elemental cerium facilitate the exposure of unsaturated Ce sites(Ce-CUS,Lewis acid(LA))and adjacent Ce-OH(Lewis base(LB))sites within the MOFs,generating abundant solid-state FLP(Ce-CUS/Ce-OH)sites.Experimental results demonstrate that Ce-CUS and Ce-OH interact with theσandσ^(*)orbitals of H-H,and this"push-pull"synergy promotes heterolytic cleavage of the H-H bond.The lone pair electrons of the electron-donating functional group are transmitted through the molecular backbone to the LB site,thereby increasing its strength and reducing the activation energy required for H_(2)heterolytic cleavage.Notably,at 100℃and 2 MPa H_(2),MOF-808-NH_(2)achieves complete conversion of styrene and dicyclopentadiene,significantly outperforming MOF-808.Based on in-situ analysis and density functional theory calculations,a plausible reaction mechanism is proposed.This research enriches the theoretical framework for unsaturated olefin hydrogenation catalysts and contributes to the development of efficient catalytic systems.展开更多
Long-cycling dendrite-free solid-state lithium metal batteries (LMBs) require fast and uniform lithium-ion (Liþ)transport of solid-state electrolytes (SSEs). However, the SSEs still face the problems of low ionic...Long-cycling dendrite-free solid-state lithium metal batteries (LMBs) require fast and uniform lithium-ion (Liþ)transport of solid-state electrolytes (SSEs). However, the SSEs still face the problems of low ionic conductivity, lowLiþ transference number, and unstable interface with lithium metal. In this work, a novel strategy of frustratedLewis pairs (FLPs) modulating solid polymer electrolytes (SPEs) has been firstly proposed that enables durable Lireversible cycling. The tunable strength of Lewis acid and base dual-active sites of nickel borate FLPs can syn-ergisticallypromote both the dissociation of lithium salts and the transfer of Liþ. As a consequence, the FLPsmodulated SPEs (SPE-NiBO-150) exhibit high ionic conductivity of 4.92×10^(-4)S cm^(-1), high Liþ transferencenumber of 0.74, and superior interface compatibility with both lithium anode and LiFePO4 cathode at room-temperature.The Li//SPE-NiBO-150//Li symmetric cell demonstrates ultralong cycle stability (over 10,000 h(417 days) at both current density of 0.2 and 0.5 mA cm〓〓2), and the assembled solid-state LiFePO4//SPE-NiBO-150//Libattery also shows excellent performance (86% capacity retention for 300 cycles at 0.5C). The presentwork supplies a new insight into designing high-performance SPEs for solid-state LMB applications.展开更多
The construction of frustrated Lewis acid-base pairs(FLPs)in porous systems is very important for the field of industrial hydrogenation catalysis,but there is still a great challenge.Based on the Ce^(3+)/Ce^(4+)redox ...The construction of frustrated Lewis acid-base pairs(FLPs)in porous systems is very important for the field of industrial hydrogenation catalysis,but there is still a great challenge.Based on the Ce^(3+)/Ce^(4+)redox pairs and abundant defects in porous Ce-based metal-organic frameworks(Ce-MOFs),FLP sites consisting of ligand-defective Ce sites(Lewis acid,LA)and neighboring terminal O sites(Lewis base,LB)were constructed in situ by a simple vacuum thermal activation method in lamellar Ce-UiO-66-F.Defects/oxygen vacancies in the Ce-MOFs structure result in the difference in the electron cloud density between Ce and O,which is suitable for H-H hetero-cleavage and H-transfer in the dicyclopentadiene(DCPD)hydrogenation process.Particularly,Ce-UiO-66-F-200 achieved 96.9%conversion of DCPD and 97.8%selectivity of 8,9-dihydrodicyclopentadiene(8,9-DHDCPD)at 100℃ under 2MPa H2 for 10 h,which is 9.4 times higher than 10.2%conversion of DCPD over the unactivated Ce-UiO-66-F.This research promotes the understanding of solid MOFs-based porous FLPs for H_(2) activation,and encourages the in-depth investigation of surface solid FLPs to the whole material FLPs.展开更多
Catalytic reduction of 4-nitrophenol(4-NP)pollutant to the high-value 4-aminophenol(4-AP)with a clean hydrogen donor holds significant importance yet great challenges owing to the difficult activation of nitro and H s...Catalytic reduction of 4-nitrophenol(4-NP)pollutant to the high-value 4-aminophenol(4-AP)with a clean hydrogen donor holds significant importance yet great challenges owing to the difficult activation of nitro and H species.In this work,Ag tailoring Frustrated Lewis pairs(FLPs)of CeO_(2)(Ag/CeO_(2))were successfully fabricated for electrochemical reduction reaction of 4-NP(4-NP ERR).As a result,the bond of Ag with O atom changed the state of the Ce-O bond and electron density,where the tailored FLPs were the key factor for enhancing absorption and activation.The reaction rate of Ag/CeO_(2)reached up to 4.70 mmol·min^(-1)(Faraday efficiency:99.5%),which was about four times of CeO_(2).Additionally,this study delved into the proton-coupled electron processes to further understand the mechanism of 4-NP ERR.Therefore,in this study,we have endeavored to investigate the role of tailored FLPs sites and utilize this structure-function relationship to achieve environmentalfriendly chemical synthesis.展开更多
Let F_(1)be the virtual field consisting of one element and(Q,I)a string pair.In this paper,we study the representations of string pairs over the virtual field F_(1).It is proved that an indecomposable F_(1)-represent...Let F_(1)be the virtual field consisting of one element and(Q,I)a string pair.In this paper,we study the representations of string pairs over the virtual field F_(1).It is proved that an indecomposable F_(1)-representation is either a string representation or a band representation by using the coefficient quivers.It is worth noting that for a given band and a positive integer,there exists a unique band representation up to isomorphism.展开更多
Sjögren’s syndrome(SS)is an autoimmune disease characterized primarily by oral and periocular dryness.Astragalus-Salvia(AS)and Ophiopogon-Dendrobium(OD)represent two frequently utilized herb pairs in SS treatmen...Sjögren’s syndrome(SS)is an autoimmune disease characterized primarily by oral and periocular dryness.Astragalus-Salvia(AS)and Ophiopogon-Dendrobium(OD)represent two frequently utilized herb pairs in SS treatment.While the combination of AS-OD herb pairs demonstrates clinical efficacy in alleviating SS symptoms,its underlying mechanism remains unclear.This investigation sought to assess the therapeutic effects and elucidate the potential mechanisms of AS-OD in non-obese diabetic(NOD)/Ltj mice with SS.The study utilized NOD/Ltj mice as SS models,administering AS-OD treatment for 10 weeks at doses of 113.1,226.2,and 339.3 mg·d−1·20 g−1.Results demonstrated that AS-OD improved SS symptoms,evidenced by enhanced salivary flow rate,decreased anti-SSA/Ro and anti-SSB/La antibody levels,increased swimming duration,and reduced lactate(LA)and blood urea nitrogen(BUN)levels in NOD/Ltj mice.AS-OD reduced lymphocyte infiltration,enhanced Aquaporin-5(AQP5)expression in the submandibular gland,decreased inflammatory cytokine levels in the submandibular gland,and reduced the T helper type 17/regulatory T lymphocyte(Th17/Treg)cell ratio in the spleen.Transcriptomic and proteomic analyses indicated AS-OD’s involvement in regulating phosphatidylinositol-3-kinase/protein kinase B(PI3K/AKT)and Janus kinase 3/signal transducer and activator of transcription 3(JAK1/STAT3)pathways,with inhibitory effects validated in both NOD/Ltj mice submandibular gland and A-253 cells.Furthermore,AS-OD enhanced cell viability and reduced A-253 cell apoptosis through the PI3K/AKT pathway.In A-253 cells,AS-OD reduced inflammatory cytokine levels,CXC chemokine ligand 9/10(CXCL9/10),and T-cell chemotaxis by inhibiting the JAK1/STAT3 pathway.AS-OD mitigates SS by suppressing inflammation and immune responses through the PI3K/AKT and JAK1/STAT3 pathways.展开更多
A series of amine-bridged bis(phenolate)rare-earth(Sc,Y)aryloxides was synthesized and characterized.These complexes were successfully used for the controlled Lewis pair polymerization(LPP)of functional acrylamides in...A series of amine-bridged bis(phenolate)rare-earth(Sc,Y)aryloxides was synthesized and characterized.These complexes were successfully used for the controlled Lewis pair polymerization(LPP)of functional acrylamides in combination with phosphines,affording a new type of polyacrylamides with predictable molecular weight and low molecular weight distribution.The living nature of this LPP was verified by near-quantitative initiation efficiencies,a linear increase of molecular weight vs monomer-to-initiator ratio and monomer conversion,chain extensions,and the synthesis of well-defined block copolymers.The mechanistic studies were performed through the isolation of a zwitterionic intermediate as well as the end-chain analysis of oligomers,showcasing a rare-earth/phosphine cooperation.Furthermore,the resultant polyacrylamides exhibit outstanding thermal stability and great potential for application in photovoltaic devices.展开更多
In this paper,we examine the functions a(n)and b(n),which respectively represent the number of cubic partitions and cubic partition pairs.Our work leads to the derivation of asymptotic formulas for both a(n)and b(n).A...In this paper,we examine the functions a(n)and b(n),which respectively represent the number of cubic partitions and cubic partition pairs.Our work leads to the derivation of asymptotic formulas for both a(n)and b(n).Additionally,we establish the upper and lower bounds of these functions,factoring in the explicit error terms involved.Crucially,our findings reveal that a(n)and b(n)both satisfy several inequalities such as log-concavity,third-order Turan inequalities,and strict log-subadditivity.展开更多
Objective:The risk factors and role of mother–child gut microbiota in pediatric inflammatory bowel disease(PIBD)remain unclear.We aimed to explore the clinical risk factors associated with PIBD,analyze the characteri...Objective:The risk factors and role of mother–child gut microbiota in pediatric inflammatory bowel disease(PIBD)remain unclear.We aimed to explore the clinical risk factors associated with PIBD,analyze the characteristics of gut microbiota of children and their mothers,and examine the correlation of the microbial composition in mother–child pairs.Methods:We conducted a case-control study including children with PIBD and their mothers as the case group,as well as healthy children and their mothers as the control group.Questionnaires were used to collect information such as family illness history and maternal and early-life events.Fecal samples were collected from the children and mothers for microbiota 16S ribosomal RNA(rRNA)sequencing to analyze the composition and its potential association with PIBD.Results:A total of 54 pairs of cases and 122 pairs of controls were recruited.A family history of autoimmune disease and antibiotic use during pregnancy were associated with an increased risk of PIBD,and a higher education level of the father was associated with a decreased risk of PIBD.Children with PIBD and mothers exhibited different gut microbiota compared to healthy children and mothers.Similarities were observed in the gut microbiota of mothers and children in the same groups.Some bacterial biomarkers of mothers discovered in this study had the power to predict PIBD in their offspring.Conclusions:PIBD is influenced by maternal risk factors and has unique gut microbiota characteristics.The mother–child gut microbiota is closely related,suggesting the transmission and influence of the gut microbiota between mothers and children.This study highlights the potential pathogenesis of PIBD and provides a basis for developing targeted interventions.展开更多
The alkaline hydrogen evolution reaction(HER)is a crucial process for sustainable hydrogen production,yet it requires efficient and stable electrocatalysts to overcome the high activation energy barrier.The article di...The alkaline hydrogen evolution reaction(HER)is a crucial process for sustainable hydrogen production,yet it requires efficient and stable electrocatalysts to overcome the high activation energy barrier.The article discusses a novel strategy for enhancing the performance of Ni-Fe layered double hydroxide(Ni-Fe LDH)in the alkaline HER by modifying it with a frustrated Lewis acid-base pair(FLP)constructed through vacancy engineering.The study found that the modified Ni-Fe LDH exhibited improved alkaline HER performance.Density functional theory(DFT)calculations demonstrate that the introduction of FLP can activate water and protons more efficiently than monometallic sites,thus reducing the alkaline HER energy barrier and overpotential.In HER under alkaline conditions,the Volmer step involves an additional hydrolysis dissociation compared to acidic conditions,which is one of the factors contributing to the slow reaction kinetics.This paper demonstrates that FLPs can alter the rate-determining step in alkaline HER from the Volmer step to a step with a lower energy barrier,more suitable for hydrogen desorption.The work provides new insights into the role of FLPs in regulating the mechanism and kinetics of HER and opens a new direction for the design and optimization of LDH-based and other electrocatalysts.展开更多
Due to its simplicity, high efficiency, and chemo-selectivity, bioorthogonal chemistry has shown a great application potential in pre-targeting.Currently, four bioorthogonal pairs as targeting tools, including (strept...Due to its simplicity, high efficiency, and chemo-selectivity, bioorthogonal chemistry has shown a great application potential in pre-targeting.Currently, four bioorthogonal pairs as targeting tools, including (strept)avidin/biotin, antibody/antigen, oligonucleotide hybridization and IEDDA tools, have been developed and applied in targeted delivery.Nevertheless, all of these tools still suffer from some limitations, such as difficult modification, biochemical fragility and larger molecular weight for biological association tools, as well as chemical instability for IEDDA tools.Synthetic host-vip pairs with relatively small molecular sizes not only possess strong chemical stability, but also have the features of fast conjugation rate, tunable binding affinity , easy modification, and high chemo-selectivity.Consequently, they can be used as a novel non-covalent bioorthogonal tool for pre-targeting.In order to further promote the development of host-vip pairs as novel bioorthogonal tools for pre-targeted delivery, we firstly calculate their conversion rate to make researcher aware of their unique advantages;next, we summarize the recent research progress in this area.The future perspectives and limitations of these unique tools will be discussed.This review will provide a systemic overview of the development of synthetic host-vip pairs as novel bioorthogonal tools for pre-targeting, and may serve as a “go for” resort for researchers who are interested in searching for new synthetic tools to improve pre-targeting.展开更多
Objective To explore the medication rules of traditional Chinese medicine(TCM)and mechanism of action of hub herb pairs for treating insomnia.Methods Totally 104 prescriptions were statistically analyzed.The associati...Objective To explore the medication rules of traditional Chinese medicine(TCM)and mechanism of action of hub herb pairs for treating insomnia.Methods Totally 104 prescriptions were statistically analyzed.The association rule algorithm was applied to mine the hub herb pairs.Network pharmacology was utilized to analyze the mechanism of the hub herb pairs,while molecular docking was applied to simulate the interaction between receptors and herb molecules,thereby predicting their binding affinities.Results The most frequently used herbs in TCM prescriptions for treating insomnia included Semen Ziziphi Spinosae,Radix Glycyrrhizae,Radix et Rhizoma Ginseng,and Poria cum Radix Pini.Among them,the most commonly used were the supplementing herbs,followed by heat-clearing,mind-calming,and exterior-releasing ones,with their properties of warm and cold,flavors of sweet,Pungent,and bitter,and meridian tropisms of liver,lungs,spleen,kidneys,heart,and stomach.The hub herb pairs based on the association rules included Radix Astragali-Radix et Rhizoma Ginseng,Rhizoma Chuanxiong-Radix Glycyrrhizae,Seman Platycladi-Semen Ziziphi Spinosae,Pericarpium Citri Reticulatae-Radix Glycyrrhizae,Radix Polygalae-Semen Ziziphi Spinosae,and Radix Astragali-Semen Ziziphi Spinosae.Network pharmacology revealed that the cAMP signaling pathway might play a key role in treating insomnia synergistically with HIF-1 signaling pathway,prolactin signaling pathway,chemical carcinogenesis receptor activation,and PI3K-Akt signaling pathway.Molecular docking indicated that there was good binding between the active ingredients of the hub herb pairs and the hub targets.Conclusions This study identified six hub herb pairs for treating insomnia in TCM.These hub herb pairs may synergistically treat insomnia with HIF-1 signaling pathway,prolactin signaling pathway,chemical carcinogenesis receptor activation,and PI3K-Akt signaling pathway through the cAMP signaling pathway.展开更多
The prevalence of smartphones is deeply embedded in modern society,impacting various aspects of our lives.Their versatility and functionalities have fundamentally changed how we communicate,work,seek entertainment,and...The prevalence of smartphones is deeply embedded in modern society,impacting various aspects of our lives.Their versatility and functionalities have fundamentally changed how we communicate,work,seek entertainment,and access information.Among the many smartphones available,those operating on the Android platform dominate,being the most widely used type.This widespread adoption of the Android OS has significantly contributed to increased malware attacks targeting the Android ecosystem in recent years.Therefore,there is an urgent need to develop new methods for detecting Android malware.The literature contains numerous works related to Android malware detection.As far as our understanding extends,we are the first ones to identify dangerous combinations of permissions and system calls to uncover malicious behavior in Android applications.We introduce a novel methodology that pairs permissions and system calls to distinguish between benign and malicious samples.This approach combines the advantages of static and dynamic analysis,offering a more comprehensive understanding of an application’s behavior.We establish covalent bonds between permissions and system calls to assess their combined impact.We introduce a novel technique to determine these pairs’Covalent Bond Strength Score.Each pair is assigned two scores,one for malicious behavior and another for benign behavior.These scores serve as the basis for classifying applications as benign or malicious.By correlating permissions with system calls,the study enables a detailed examination of how an app utilizes its requested permissions,aiding in differentiating legitimate and potentially harmful actions.This comprehensive analysis provides a robust framework for Android malware detection,marking a significant contribution to the field.The results of our experiments demonstrate a remarkable overall accuracy of 97.5%,surpassing various state-of-the-art detection techniques proposed in the current literature.展开更多
The utilization of sequence stratigraphic concepts in identifying sands and their spatial continuity in distinct gross depositional settings is key,especially in frontier settings where data paucity is a common challe...The utilization of sequence stratigraphic concepts in identifying sands and their spatial continuity in distinct gross depositional settings is key,especially in frontier settings where data paucity is a common challenge.In the Baka field,onshore Niger Delta,detailed reservoir correlation guided by sequence stratigraphic framework analysis showed the distribution of sand and shale units constituting reservoirseal pairs(RSP)correlatable across the field.Within the 3rd-order packages,it is observed that the lowstand systems tract(LST)and highstand systems tract(HST)contain more RSPs and thicker 4th-and 5th-order sands than the transgressive systems tract(TST).In terms of bathymetry,it is noted that irrespective of systems tracts,the RSP Index(RI)decreases from the proximal shallow/inner shelf settings to the more distal outer shelf areas.Amongst all three systems tracts,intervals interpreted as lowstand prograding complexes contain the best developed sands and highest RSP.Sand development within the LSTs has been controlled by a pronounced growth fault regime accompanied by high subsidence and sedimentation rates.This is linked to the basinward migration of the sands during prolonged sea-level fall,creating significant accommodation space for sand deposition.On the other hand,the TSTs known to mark periods of progressive sea-level rise and landward migration of sandy facies,show thinner sands enclosed in much thicker,laterally extensive,and better-preserved deeper marine shales.Interpreted seismic sections indicate intense growth faulting and channelization that influenced the syn-and postdepositional development of the sand packages across the field.The initial timing of deformation of subregional faults in this area coincides with periods of abrupt falls in sea level.This approach could be useful for predicting sand-prone areas in frontier fields as well as possible reservoir-seal parameters required for some aspects of petroleum system analysis and quick-look volume estimation.展开更多
This study reports a passive mode-locked Thulium-Holmium co-doped fiber laser featuring a figure-9 shaped resonator structure.The laser utilizes a nonlinear amplifying loop mirror(NALM)as the mode-locking device.By in...This study reports a passive mode-locked Thulium-Holmium co-doped fiber laser featuring a figure-9 shaped resonator structure.The laser utilizes a nonlinear amplifying loop mirror(NALM)as the mode-locking device.By increasing pump power,the laser’s output evolution was experimentally observed,showing that bright-dark pulse pairs first split into double pulses and then into a second harmonic state.Additionally,the time intervals between bright and dark pulses and between double pulses increased with higher pump power.The RF spectrum of the bright-dark pulse pairs exhibited envelope modulation,with a modulation frequency approximately equal to the reciprocal of the time interval between bright and dark pulses.When the pump power increased from 0.46 W to 0.72 W,the reciprocal of the modulation frequency showed a linear growth trend.These findings contribute to understanding the evolution patterns of bright-dark pulse pairs in passive mode-locked fiber lasers.展开更多
Broadband photon pairs are highly desirable for quantum metrology,quantum sensing,and quantum communication.Such sources are usually designed through type-0 phase-matching spontaneous parametric down-conversion(SPDC)t...Broadband photon pairs are highly desirable for quantum metrology,quantum sensing,and quantum communication.Such sources are usually designed through type-0 phase-matching spontaneous parametric down-conversion(SPDC)that makes the photon pairs hard to separate in the frequency-degenerate case and thus limits their applications.In this paper,we design a broadband frequency-degenerate telecom-band photon pair source via the type-II SPDC in a dispersion-engineered thin-film lithium niobate waveguide,where the polarization modes of photon pairs are orthogonal and thus are easily separated deterministically.With a 5-mm-long waveguide,our design can achieve a bandwidth of 5.56 THz(44.8 nm),which is 8.6 times larger than that of the bulk lithium niobate,and the central wavelength can be flexibly adjusted.Our design is a promising approach towards high-quality integrated photon sources and may have wide applications in photonic quantum technologies.展开更多
Electrochemical carbon dioxide reduction reaction(CO_(2)RR)involves a variety of intermediates with highly correlated reaction and ad-desorption energies,hindering optimization of the catalytic activity.For example,in...Electrochemical carbon dioxide reduction reaction(CO_(2)RR)involves a variety of intermediates with highly correlated reaction and ad-desorption energies,hindering optimization of the catalytic activity.For example,increasing the binding of the*COOH to the active site will generally increase the*CO desorption energy.Breaking this relationship may be expected to dramatically improve the intrinsic activity of CO_(2)RR,but remains an unsolved challenge.Herein,we addressed this conundrum by constructing a unique atomic dispersed hetero-pair consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier.This system shows an unprecedented CO_(2)RR intrinsic activity with TOF of 3336 h−1,high selectivity toward CO production,Faradaic efficiency of 95.96%at−0.60 V and excellent stability.Theoretical calculations show that the Mo-Fe diatomic sites increased the*COOH intermediate adsorption energy by bridging adsorption of*COOH intermediates.At the same time,d-d orbital coupling in the Mo-Fe di-atom results in electron delocalization and facilitates desorption of*CO intermediates.Thus,the undesirable correlation between these steps is broken.This work provides a promising approach,specifically the use of di-atoms,for breaking unfavorable relationships based on understanding of the catalytic mechanisms at the atomic scale.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12225509),the National Natural Science Foundation of China(Grant No.12247101)the Polish National Science Centre(Grant No.2024/53/B/ST2/00975)+2 种基金the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2024-jdzx06)the Natural Science Foundation of Gansu Province(Grant No.22JR5RA389)the‘111 Center’under Grant No.B20063。
文摘Decays of charmonium into hyperon and antihyperon pairs provide a pristine laboratory for exploring hyperon properties,such as their polarization and decay parameters,and for conducting tests of fundamental symmetries.This brief review highlights the significant progress made in precise tests of CP symmetry at BESIII using entangled hyperon-antihyperon pairs。
基金supported by the National Natural Science Foundation of China(22302115,22072079)the Fundamental Research Program of Shanxi Province(202303021221056).
文摘Heterogeneous solid frustrated-Lewis-pair(FLP)catalyst is of great promise in practical hydrogenation applications.It has been found that all-solid FLPs can be created on ceria via surface oxygen vacancy regulation.Consequently,it is desired to investigate the mechanisms of the FLP-catalyzed hydrogenation of C=C and C=O and provide insight into the modification of CeO_(2)catalysts for the selective hydrogenation.In this work,the reaction mechanism of the hydrogenation of CH_(2)=CH_(2)and CH_(3)CH=O at the FLP sites constructed on CeO_(2)(110)surface was investigated by density functional theory(DFT),with the classical Lewis acid-base pairs(CLP)site as the reference.The results illustrate that at the CLP site,the dissociated hydride(H^(δ−))forms a stable H−O bond with the surface O atom,while at the FLP site,H^(δ−)is stabilized by Ce,displaying higher activity on the one hand.On the other hand,the electron cloud density of the Ce atom at the FLP site is higher,which can transfer more electrons to the adsorbed C_(C=C)and O_(C=O)atoms,leading to a higher degree of activation for C=C and C=O bonds,as indicated by the Bader charge analysis.Therefore,compared to the CLP site,the FLP site exhibits higher hydrogenation activity for CH_(2)=CH_(2)and CH_(3)CH=O.Furthermore,at the FLP sites,it demonstrates high efficiency in catalyzing the hydrogenation of CH_(2)=CH_(2)with the rate-determining barrier of 1.04 eV,but it shows limited activity for the hydrogenation of CH_(3)CH=O with the rate-determining barrier of 1.94 eV.It means that the selective hydrogenation of C=C can be effectively achieved at the FLP sites concerning selective hydrogenation catalysis.The insights shown in this work help to clarify the reaction mechanism of the hydrogenation of C=C and C=O at FLP site on CeO_(2)(110)and reveal the relationship between the catalytic performance and the nature of the active site,which is of great benefit to development of rational design of heterogeneous FLP catalysts.
文摘The development of solid frustrated Lewis pairs(FLPs)catalysts with porous structures is a promising strategy for advancing green hydrogenation technologies and has garnered significant attention.Leveraging the diverse oxidation states and structural tunability of cerium-based metal-organic frameworks(Ce-MOFs),this study employed a competitive coordination strategy utilizing a single carboxylate functional group ligand to construct a series of MOF-808-X(X=-NH_(2),-OH,-Br,and-NO_(2))featuring rich solid-state FLPs for hydrogenation of unsaturated olefins.The-X functional group serves as a microenvironment,enhancing hydrogenation activity by modulating the electronic properties and acid-base characteristics of the FLP sites.The unique redox properties of elemental cerium facilitate the exposure of unsaturated Ce sites(Ce-CUS,Lewis acid(LA))and adjacent Ce-OH(Lewis base(LB))sites within the MOFs,generating abundant solid-state FLP(Ce-CUS/Ce-OH)sites.Experimental results demonstrate that Ce-CUS and Ce-OH interact with theσandσ^(*)orbitals of H-H,and this"push-pull"synergy promotes heterolytic cleavage of the H-H bond.The lone pair electrons of the electron-donating functional group are transmitted through the molecular backbone to the LB site,thereby increasing its strength and reducing the activation energy required for H_(2)heterolytic cleavage.Notably,at 100℃and 2 MPa H_(2),MOF-808-NH_(2)achieves complete conversion of styrene and dicyclopentadiene,significantly outperforming MOF-808.Based on in-situ analysis and density functional theory calculations,a plausible reaction mechanism is proposed.This research enriches the theoretical framework for unsaturated olefin hydrogenation catalysts and contributes to the development of efficient catalytic systems.
基金supported by the National Natural Science Foundation of China(52162036,52174284 and 22378342)the Key Project of Nature Science Foundation of Xinjiang Province(2021D01D08)the Key Research and Development Program of Hunan Province(2024JK2094).
文摘Long-cycling dendrite-free solid-state lithium metal batteries (LMBs) require fast and uniform lithium-ion (Liþ)transport of solid-state electrolytes (SSEs). However, the SSEs still face the problems of low ionic conductivity, lowLiþ transference number, and unstable interface with lithium metal. In this work, a novel strategy of frustratedLewis pairs (FLPs) modulating solid polymer electrolytes (SPEs) has been firstly proposed that enables durable Lireversible cycling. The tunable strength of Lewis acid and base dual-active sites of nickel borate FLPs can syn-ergisticallypromote both the dissociation of lithium salts and the transfer of Liþ. As a consequence, the FLPsmodulated SPEs (SPE-NiBO-150) exhibit high ionic conductivity of 4.92×10^(-4)S cm^(-1), high Liþ transferencenumber of 0.74, and superior interface compatibility with both lithium anode and LiFePO4 cathode at room-temperature.The Li//SPE-NiBO-150//Li symmetric cell demonstrates ultralong cycle stability (over 10,000 h(417 days) at both current density of 0.2 and 0.5 mA cm〓〓2), and the assembled solid-state LiFePO4//SPE-NiBO-150//Libattery also shows excellent performance (86% capacity retention for 300 cycles at 0.5C). The presentwork supplies a new insight into designing high-performance SPEs for solid-state LMB applications.
基金supported by the National Key Research and Development Program of China(No.2021YFB3500700)the National Natural Science Foundation of China(No.51972024)+1 种基金Natural Science Foundation of Guangdong Province(No.2022A1515010185)Fundamental Research Funds for the Central Universities(No.FRFEYIT-23-07).
文摘The construction of frustrated Lewis acid-base pairs(FLPs)in porous systems is very important for the field of industrial hydrogenation catalysis,but there is still a great challenge.Based on the Ce^(3+)/Ce^(4+)redox pairs and abundant defects in porous Ce-based metal-organic frameworks(Ce-MOFs),FLP sites consisting of ligand-defective Ce sites(Lewis acid,LA)and neighboring terminal O sites(Lewis base,LB)were constructed in situ by a simple vacuum thermal activation method in lamellar Ce-UiO-66-F.Defects/oxygen vacancies in the Ce-MOFs structure result in the difference in the electron cloud density between Ce and O,which is suitable for H-H hetero-cleavage and H-transfer in the dicyclopentadiene(DCPD)hydrogenation process.Particularly,Ce-UiO-66-F-200 achieved 96.9%conversion of DCPD and 97.8%selectivity of 8,9-dihydrodicyclopentadiene(8,9-DHDCPD)at 100℃ under 2MPa H2 for 10 h,which is 9.4 times higher than 10.2%conversion of DCPD over the unactivated Ce-UiO-66-F.This research promotes the understanding of solid MOFs-based porous FLPs for H_(2) activation,and encourages the in-depth investigation of surface solid FLPs to the whole material FLPs.
基金supported by National Natural Science Foundation of China(22075112)Opening Foundation of State Key Laboratory of Rare Earth Resource Utilization(RERU2023010)+1 种基金Opening Foundation of Key Laboratory of Functional Inorganic Material Chemistry(Heilongjiang University)Ministry of Education,China,Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX24_4006).
文摘Catalytic reduction of 4-nitrophenol(4-NP)pollutant to the high-value 4-aminophenol(4-AP)with a clean hydrogen donor holds significant importance yet great challenges owing to the difficult activation of nitro and H species.In this work,Ag tailoring Frustrated Lewis pairs(FLPs)of CeO_(2)(Ag/CeO_(2))were successfully fabricated for electrochemical reduction reaction of 4-NP(4-NP ERR).As a result,the bond of Ag with O atom changed the state of the Ce-O bond and electron density,where the tailored FLPs were the key factor for enhancing absorption and activation.The reaction rate of Ag/CeO_(2)reached up to 4.70 mmol·min^(-1)(Faraday efficiency:99.5%),which was about four times of CeO_(2).Additionally,this study delved into the proton-coupled electron processes to further understand the mechanism of 4-NP ERR.Therefore,in this study,we have endeavored to investigate the role of tailored FLPs sites and utilize this structure-function relationship to achieve environmentalfriendly chemical synthesis.
文摘Let F_(1)be the virtual field consisting of one element and(Q,I)a string pair.In this paper,we study the representations of string pairs over the virtual field F_(1).It is proved that an indecomposable F_(1)-representation is either a string representation or a band representation by using the coefficient quivers.It is worth noting that for a given band and a positive integer,there exists a unique band representation up to isomorphism.
基金the National Natural Science Foundation of China(No.82074341).
文摘Sjögren’s syndrome(SS)is an autoimmune disease characterized primarily by oral and periocular dryness.Astragalus-Salvia(AS)and Ophiopogon-Dendrobium(OD)represent two frequently utilized herb pairs in SS treatment.While the combination of AS-OD herb pairs demonstrates clinical efficacy in alleviating SS symptoms,its underlying mechanism remains unclear.This investigation sought to assess the therapeutic effects and elucidate the potential mechanisms of AS-OD in non-obese diabetic(NOD)/Ltj mice with SS.The study utilized NOD/Ltj mice as SS models,administering AS-OD treatment for 10 weeks at doses of 113.1,226.2,and 339.3 mg·d−1·20 g−1.Results demonstrated that AS-OD improved SS symptoms,evidenced by enhanced salivary flow rate,decreased anti-SSA/Ro and anti-SSB/La antibody levels,increased swimming duration,and reduced lactate(LA)and blood urea nitrogen(BUN)levels in NOD/Ltj mice.AS-OD reduced lymphocyte infiltration,enhanced Aquaporin-5(AQP5)expression in the submandibular gland,decreased inflammatory cytokine levels in the submandibular gland,and reduced the T helper type 17/regulatory T lymphocyte(Th17/Treg)cell ratio in the spleen.Transcriptomic and proteomic analyses indicated AS-OD’s involvement in regulating phosphatidylinositol-3-kinase/protein kinase B(PI3K/AKT)and Janus kinase 3/signal transducer and activator of transcription 3(JAK1/STAT3)pathways,with inhibitory effects validated in both NOD/Ltj mice submandibular gland and A-253 cells.Furthermore,AS-OD enhanced cell viability and reduced A-253 cell apoptosis through the PI3K/AKT pathway.In A-253 cells,AS-OD reduced inflammatory cytokine levels,CXC chemokine ligand 9/10(CXCL9/10),and T-cell chemotaxis by inhibiting the JAK1/STAT3 pathway.AS-OD mitigates SS by suppressing inflammation and immune responses through the PI3K/AKT and JAK1/STAT3 pathways.
基金supported by National Natural Science Foundation of China(21871204,22371198)Postgraduate Research&Practice Innovation Program of Jiangsu Province。
文摘A series of amine-bridged bis(phenolate)rare-earth(Sc,Y)aryloxides was synthesized and characterized.These complexes were successfully used for the controlled Lewis pair polymerization(LPP)of functional acrylamides in combination with phosphines,affording a new type of polyacrylamides with predictable molecular weight and low molecular weight distribution.The living nature of this LPP was verified by near-quantitative initiation efficiencies,a linear increase of molecular weight vs monomer-to-initiator ratio and monomer conversion,chain extensions,and the synthesis of well-defined block copolymers.The mechanistic studies were performed through the isolation of a zwitterionic intermediate as well as the end-chain analysis of oligomers,showcasing a rare-earth/phosphine cooperation.Furthermore,the resultant polyacrylamides exhibit outstanding thermal stability and great potential for application in photovoltaic devices.
基金supported by the National Natural Science Foundation of China(12371327)the Natural Science Foundation of Chongqing(cstc2021jcyj-msxmX0107).
文摘In this paper,we examine the functions a(n)and b(n),which respectively represent the number of cubic partitions and cubic partition pairs.Our work leads to the derivation of asymptotic formulas for both a(n)and b(n).Additionally,we establish the upper and lower bounds of these functions,factoring in the explicit error terms involved.Crucially,our findings reveal that a(n)and b(n)both satisfy several inequalities such as log-concavity,third-order Turan inequalities,and strict log-subadditivity.
基金supported by the National Key R&D Program of China(Nos.2021YFA1301300,2019YFA0905600,and 2023YFC2706503)the National Natural Science Foundation of China(Nos.82170557 and 82000510).
文摘Objective:The risk factors and role of mother–child gut microbiota in pediatric inflammatory bowel disease(PIBD)remain unclear.We aimed to explore the clinical risk factors associated with PIBD,analyze the characteristics of gut microbiota of children and their mothers,and examine the correlation of the microbial composition in mother–child pairs.Methods:We conducted a case-control study including children with PIBD and their mothers as the case group,as well as healthy children and their mothers as the control group.Questionnaires were used to collect information such as family illness history and maternal and early-life events.Fecal samples were collected from the children and mothers for microbiota 16S ribosomal RNA(rRNA)sequencing to analyze the composition and its potential association with PIBD.Results:A total of 54 pairs of cases and 122 pairs of controls were recruited.A family history of autoimmune disease and antibiotic use during pregnancy were associated with an increased risk of PIBD,and a higher education level of the father was associated with a decreased risk of PIBD.Children with PIBD and mothers exhibited different gut microbiota compared to healthy children and mothers.Similarities were observed in the gut microbiota of mothers and children in the same groups.Some bacterial biomarkers of mothers discovered in this study had the power to predict PIBD in their offspring.Conclusions:PIBD is influenced by maternal risk factors and has unique gut microbiota characteristics.The mother–child gut microbiota is closely related,suggesting the transmission and influence of the gut microbiota between mothers and children.This study highlights the potential pathogenesis of PIBD and provides a basis for developing targeted interventions.
基金financially supported by National Natural Science Foundation of China(Nos.52301011,52231008,52142304,52177220,U23A200767,52302236,and 22369005)Hainan Provincial Natural Science Foundation of China(Nos.524QN226 and 524QN222)+2 种基金the Key Research and Development Program of Hainan Province(No.ZDYF2022GXJS006)Starting Research Fund from the Hainan University(No.KYQD(ZR)23026)International Science&Technology Cooperation Program of Hainan Province(No.GHYF2023007).
文摘The alkaline hydrogen evolution reaction(HER)is a crucial process for sustainable hydrogen production,yet it requires efficient and stable electrocatalysts to overcome the high activation energy barrier.The article discusses a novel strategy for enhancing the performance of Ni-Fe layered double hydroxide(Ni-Fe LDH)in the alkaline HER by modifying it with a frustrated Lewis acid-base pair(FLP)constructed through vacancy engineering.The study found that the modified Ni-Fe LDH exhibited improved alkaline HER performance.Density functional theory(DFT)calculations demonstrate that the introduction of FLP can activate water and protons more efficiently than monometallic sites,thus reducing the alkaline HER energy barrier and overpotential.In HER under alkaline conditions,the Volmer step involves an additional hydrolysis dissociation compared to acidic conditions,which is one of the factors contributing to the slow reaction kinetics.This paper demonstrates that FLPs can alter the rate-determining step in alkaline HER from the Volmer step to a step with a lower energy barrier,more suitable for hydrogen desorption.The work provides new insights into the role of FLPs in regulating the mechanism and kinetics of HER and opens a new direction for the design and optimization of LDH-based and other electrocatalysts.
基金supported by the Science and Technology Program of Guangzhou(No.202103000089)the National Natural Science Foundation of China(Nos.22271323 and 22071275)+2 种基金the Innovation Team Project of Universities in Guangdong Province(No.2020KCXTD009)the Scientific and Technological Innovation Leading Talent Project of Zhongshan City(No.LJ2021009)the Key Projects of Social Welfare and Basic Research of Zhongshan City(No.2021B2012).
文摘Due to its simplicity, high efficiency, and chemo-selectivity, bioorthogonal chemistry has shown a great application potential in pre-targeting.Currently, four bioorthogonal pairs as targeting tools, including (strept)avidin/biotin, antibody/antigen, oligonucleotide hybridization and IEDDA tools, have been developed and applied in targeted delivery.Nevertheless, all of these tools still suffer from some limitations, such as difficult modification, biochemical fragility and larger molecular weight for biological association tools, as well as chemical instability for IEDDA tools.Synthetic host-vip pairs with relatively small molecular sizes not only possess strong chemical stability, but also have the features of fast conjugation rate, tunable binding affinity , easy modification, and high chemo-selectivity.Consequently, they can be used as a novel non-covalent bioorthogonal tool for pre-targeting.In order to further promote the development of host-vip pairs as novel bioorthogonal tools for pre-targeted delivery, we firstly calculate their conversion rate to make researcher aware of their unique advantages;next, we summarize the recent research progress in this area.The future perspectives and limitations of these unique tools will be discussed.This review will provide a systemic overview of the development of synthetic host-vip pairs as novel bioorthogonal tools for pre-targeting, and may serve as a “go for” resort for researchers who are interested in searching for new synthetic tools to improve pre-targeting.
基金National Natural Science Foundation of China(82360905)Gansu Provincial University Teachers'Innovation Fund Projects(2023A-092 and 2024B-109).
文摘Objective To explore the medication rules of traditional Chinese medicine(TCM)and mechanism of action of hub herb pairs for treating insomnia.Methods Totally 104 prescriptions were statistically analyzed.The association rule algorithm was applied to mine the hub herb pairs.Network pharmacology was utilized to analyze the mechanism of the hub herb pairs,while molecular docking was applied to simulate the interaction between receptors and herb molecules,thereby predicting their binding affinities.Results The most frequently used herbs in TCM prescriptions for treating insomnia included Semen Ziziphi Spinosae,Radix Glycyrrhizae,Radix et Rhizoma Ginseng,and Poria cum Radix Pini.Among them,the most commonly used were the supplementing herbs,followed by heat-clearing,mind-calming,and exterior-releasing ones,with their properties of warm and cold,flavors of sweet,Pungent,and bitter,and meridian tropisms of liver,lungs,spleen,kidneys,heart,and stomach.The hub herb pairs based on the association rules included Radix Astragali-Radix et Rhizoma Ginseng,Rhizoma Chuanxiong-Radix Glycyrrhizae,Seman Platycladi-Semen Ziziphi Spinosae,Pericarpium Citri Reticulatae-Radix Glycyrrhizae,Radix Polygalae-Semen Ziziphi Spinosae,and Radix Astragali-Semen Ziziphi Spinosae.Network pharmacology revealed that the cAMP signaling pathway might play a key role in treating insomnia synergistically with HIF-1 signaling pathway,prolactin signaling pathway,chemical carcinogenesis receptor activation,and PI3K-Akt signaling pathway.Molecular docking indicated that there was good binding between the active ingredients of the hub herb pairs and the hub targets.Conclusions This study identified six hub herb pairs for treating insomnia in TCM.These hub herb pairs may synergistically treat insomnia with HIF-1 signaling pathway,prolactin signaling pathway,chemical carcinogenesis receptor activation,and PI3K-Akt signaling pathway through the cAMP signaling pathway.
文摘The prevalence of smartphones is deeply embedded in modern society,impacting various aspects of our lives.Their versatility and functionalities have fundamentally changed how we communicate,work,seek entertainment,and access information.Among the many smartphones available,those operating on the Android platform dominate,being the most widely used type.This widespread adoption of the Android OS has significantly contributed to increased malware attacks targeting the Android ecosystem in recent years.Therefore,there is an urgent need to develop new methods for detecting Android malware.The literature contains numerous works related to Android malware detection.As far as our understanding extends,we are the first ones to identify dangerous combinations of permissions and system calls to uncover malicious behavior in Android applications.We introduce a novel methodology that pairs permissions and system calls to distinguish between benign and malicious samples.This approach combines the advantages of static and dynamic analysis,offering a more comprehensive understanding of an application’s behavior.We establish covalent bonds between permissions and system calls to assess their combined impact.We introduce a novel technique to determine these pairs’Covalent Bond Strength Score.Each pair is assigned two scores,one for malicious behavior and another for benign behavior.These scores serve as the basis for classifying applications as benign or malicious.By correlating permissions with system calls,the study enables a detailed examination of how an app utilizes its requested permissions,aiding in differentiating legitimate and potentially harmful actions.This comprehensive analysis provides a robust framework for Android malware detection,marking a significant contribution to the field.The results of our experiments demonstrate a remarkable overall accuracy of 97.5%,surpassing various state-of-the-art detection techniques proposed in the current literature.
基金sponsored by the Shell Petroleum Development Company of Nigeria Limited(SPDC).
文摘The utilization of sequence stratigraphic concepts in identifying sands and their spatial continuity in distinct gross depositional settings is key,especially in frontier settings where data paucity is a common challenge.In the Baka field,onshore Niger Delta,detailed reservoir correlation guided by sequence stratigraphic framework analysis showed the distribution of sand and shale units constituting reservoirseal pairs(RSP)correlatable across the field.Within the 3rd-order packages,it is observed that the lowstand systems tract(LST)and highstand systems tract(HST)contain more RSPs and thicker 4th-and 5th-order sands than the transgressive systems tract(TST).In terms of bathymetry,it is noted that irrespective of systems tracts,the RSP Index(RI)decreases from the proximal shallow/inner shelf settings to the more distal outer shelf areas.Amongst all three systems tracts,intervals interpreted as lowstand prograding complexes contain the best developed sands and highest RSP.Sand development within the LSTs has been controlled by a pronounced growth fault regime accompanied by high subsidence and sedimentation rates.This is linked to the basinward migration of the sands during prolonged sea-level fall,creating significant accommodation space for sand deposition.On the other hand,the TSTs known to mark periods of progressive sea-level rise and landward migration of sandy facies,show thinner sands enclosed in much thicker,laterally extensive,and better-preserved deeper marine shales.Interpreted seismic sections indicate intense growth faulting and channelization that influenced the syn-and postdepositional development of the sand packages across the field.The initial timing of deformation of subregional faults in this area coincides with periods of abrupt falls in sea level.This approach could be useful for predicting sand-prone areas in frontier fields as well as possible reservoir-seal parameters required for some aspects of petroleum system analysis and quick-look volume estimation.
文摘This study reports a passive mode-locked Thulium-Holmium co-doped fiber laser featuring a figure-9 shaped resonator structure.The laser utilizes a nonlinear amplifying loop mirror(NALM)as the mode-locking device.By increasing pump power,the laser’s output evolution was experimentally observed,showing that bright-dark pulse pairs first split into double pulses and then into a second harmonic state.Additionally,the time intervals between bright and dark pulses and between double pulses increased with higher pump power.The RF spectrum of the bright-dark pulse pairs exhibited envelope modulation,with a modulation frequency approximately equal to the reciprocal of the time interval between bright and dark pulses.When the pump power increased from 0.46 W to 0.72 W,the reciprocal of the modulation frequency showed a linear growth trend.These findings contribute to understanding the evolution patterns of bright-dark pulse pairs in passive mode-locked fiber lasers.
基金Project supported by the National Key Research and Development Program of China(Grant No.2019YFA0705000)Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301500)+1 种基金Leading-edge Technology Program of Jiangsu Natural Science Foundation(Grant No.BK20192001)the National Natural Science Foundation of China(Grant Nos.51890861 and 11974178).
文摘Broadband photon pairs are highly desirable for quantum metrology,quantum sensing,and quantum communication.Such sources are usually designed through type-0 phase-matching spontaneous parametric down-conversion(SPDC)that makes the photon pairs hard to separate in the frequency-degenerate case and thus limits their applications.In this paper,we design a broadband frequency-degenerate telecom-band photon pair source via the type-II SPDC in a dispersion-engineered thin-film lithium niobate waveguide,where the polarization modes of photon pairs are orthogonal and thus are easily separated deterministically.With a 5-mm-long waveguide,our design can achieve a bandwidth of 5.56 THz(44.8 nm),which is 8.6 times larger than that of the bulk lithium niobate,and the central wavelength can be flexibly adjusted.Our design is a promising approach towards high-quality integrated photon sources and may have wide applications in photonic quantum technologies.
基金the National Natural Science Foundation of China(22279044,12034002,and 22202080)the Project for Self-Innovation Capability Construction of Jilin Province Development and Reform Commission(2021C026)+1 种基金Jilin Province Science and Technology Development Program(20210301009GX)the Fundamental Research Funds for the Central Universities.
文摘Electrochemical carbon dioxide reduction reaction(CO_(2)RR)involves a variety of intermediates with highly correlated reaction and ad-desorption energies,hindering optimization of the catalytic activity.For example,increasing the binding of the*COOH to the active site will generally increase the*CO desorption energy.Breaking this relationship may be expected to dramatically improve the intrinsic activity of CO_(2)RR,but remains an unsolved challenge.Herein,we addressed this conundrum by constructing a unique atomic dispersed hetero-pair consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier.This system shows an unprecedented CO_(2)RR intrinsic activity with TOF of 3336 h−1,high selectivity toward CO production,Faradaic efficiency of 95.96%at−0.60 V and excellent stability.Theoretical calculations show that the Mo-Fe diatomic sites increased the*COOH intermediate adsorption energy by bridging adsorption of*COOH intermediates.At the same time,d-d orbital coupling in the Mo-Fe di-atom results in electron delocalization and facilitates desorption of*CO intermediates.Thus,the undesirable correlation between these steps is broken.This work provides a promising approach,specifically the use of di-atoms,for breaking unfavorable relationships based on understanding of the catalytic mechanisms at the atomic scale.
