The measurement of the pairing gap is crucial for investigating the physical properties of superconductors or superfluids.We propose a strategy to measure the pairing gap through the dynamical excitations.With the ran...The measurement of the pairing gap is crucial for investigating the physical properties of superconductors or superfluids.We propose a strategy to measure the pairing gap through the dynamical excitations.With the random phase approximation(RPA),we study the dynamical excitations of a two-dimensional attractive Fermi-Hubbard model by calculating its dynamical structure factor.Two distinct collective modes emerge:a Goldstone phonon mode at transferred momentum q=[0,0]and a roton mode at q=[p,p].The roton mode exhibits a sharp molecular peak in the low-energy regime.Notably,the area under the roton molecular peak scales with the square of the pairing gap,which holds even in three-dimensional and spin-orbit coupled(SOC)optical lattices.This finding suggests an experimental approach to measure the pairing gap in lattice systems by analyzing the dynamical structure factor at q=[p,p].展开更多
Recent various experiments have provided evidence supporting the emergence of loop-current order in kagome metals. Particularly superconductivity in AV_(3)Sb_(5) is significantly enhanced when this charge order is sup...Recent various experiments have provided evidence supporting the emergence of loop-current order in kagome metals. Particularly superconductivity in AV_(3)Sb_(5) is significantly enhanced when this charge order is suppressed by pressure or doping. Distinct from magnetic order, loop-current order does not couple directly to spin and thus whether such fluctuations can enhance superconductivity remains elusive. We design a sign problem-free bilayer kagome model coupled to quantum Ising spins through bond currents and perform determinant quantum Monte Carlo simulations to explore single-particle properties and superconductivity arising from 2 × 2 loopcurrent fluctuations. We find that this loop-current order induces intriguing band folding, band broadening,and gap opening around saddle points. Remarkably, our pairing susceptibility analysis identifies a dominant enhancement of superconductivity due to loop-current fluctuations, with the dominant pairing being the chiral d-wave channel. This pairing primarily occurs within the intra-sublattice channel and involves third nearestneighbor sites, attributed to the unique sublattice texture associated with van Hove singularities. We also discuss potential experimental implications for kagome superconductors.展开更多
The infection of SARS-CoV-2 has triggered the COVID-19 pandemic. In addition to the fever and respiratory symptoms in the process of coronavirus infections, gastrointestinal symptoms, especially diarrhea, are prominen...The infection of SARS-CoV-2 has triggered the COVID-19 pandemic. In addition to the fever and respiratory symptoms in the process of coronavirus infections, gastrointestinal symptoms, especially diarrhea, are prominent features of its acute infection and long COVID. The associations between the lung and large intestine have been demonstrated by Western medicine in aspects such as tissue origin, microflora homeostasis, mucosal immunity, renin-angiotensin system(RAS) and autonomic nervous system as well, which are considered as the evidence of material basis and potential regulatory mechanisms for “gutlung crosstalk(肺肠串扰)” in COVID-19. We have noticed that probiotics and other preparations can regulate the intestines, and further treat COVID-19 with effective and gratifying results. In the system of traditional Chinese medicine(TCM), there's a term of “exterior-interior pairing of the lung and large intestine(肺与大肠相表里)”, showing an interconnection of the lung and the bowels. “Exterior-interior pairing of the lung and large intestine” is an important part of the theory of visceral activities proposed by ancient physicians through a long-term observation and practice. It's considered that “lung” and “large intestine” are interconnected and mutually exterior-interior in the normal physical activities and the disease development, providing a theoretical basis for treating lung diseases and bowel diseases from the perspective of overall concept. The study aims to compare the term of “exterior-interior pairing of the lung and large intestine” in TCM and “gut-lung crosstalk” in Western medicine regarding the development of COVID-19 and its intestinal symptoms, and provide more ideas for diagnosing and treating lung and bowel related diseases.展开更多
The stable Bardeen-Schrieffer-Cooper(BCS)pairing state of a bosonic system has long been sought theoretically and experimentally.Here we propose that a stable BCS state of bosons can be realized in a binary Bose gas w...The stable Bardeen-Schrieffer-Cooper(BCS)pairing state of a bosonic system has long been sought theoretically and experimentally.Here we propose that a stable BCS state of bosons can be realized in a binary Bose gas with s-wave intra-species repulsion and an inter-species attraction in the mean-field-stable region.We find that above the Bose-Einstein condensation(BEC)transition temperature,there is a phase transition from the normal state to a BCS state driven by interspecies pairing.When the temperature decreases,another phase transition from the BCS state to a mixed state featuring both atomic BEC and inter-species pairing occurs.As the temperature is further lowered,the mixed state is eventually taken over by the pure BEC state.We present the phase diagram of this system and discuss its experimental implications.展开更多
The combined lines having both phKL and Ph2-deficiency were obtained in the genetic background of common wheat (Triticum aestivum L.) landrace. These lines had normal fertility. In the wheat combined lines X Aegilops ...The combined lines having both phKL and Ph2-deficiency were obtained in the genetic background of common wheat (Triticum aestivum L.) landrace. These lines had normal fertility. In the wheat combined lines X Aegilops variabilis Eig. (or rye), a significant increase in the chiasmata of homoeologous pairing was shown by the phKL+Ph2(-) plants with respect to their phKL+Ph2 sibs, which indicates that Ph2-deficiency and phKL showed an additive effect on promoting pairing. The effects were shown in the increment of rod bivalents, ring bivalents and trivalents and reduction of univalents, of which, reduction of univalents was mainly due to the increment of rod bivalents. The combined lines are probably more desirable materials for alien gene transferring than phKL or Ph2(-) lines alone. In comparison with that of ph1b X Ae. variabilis (or rye), phKL+Ph2(-) X Ae. variabilis (or rye) show higher (or similar) numbers of rod bivalents, while the total chromosome pairing level significantly reduced that ascribed to the decrement in ring bivalents and multivalents. These results probably indicate the different genetic mechanisms for Ph1 and Ph2 or phKL on controlling homoeologous pairing.展开更多
To improve the reliable performance of information transmission in cooperative relay networks, the scheme of the max-rate spatial channel pairing （SCP） based on maximum ratio combining （MRC） is proposed. The schem...To improve the reliable performance of information transmission in cooperative relay networks, the scheme of the max-rate spatial channel pairing （SCP） based on maximum ratio combining （MRC） is proposed. The scheme includes three steps： channel phase cancellation, MRC, and SCP. Eventually, the solution of the scheme is modeled as convex optimization. The objective function of the optimization problem is to maximize the transmission rate and the optimization variable is the strategy of pairing between the uplink spatial sub-channels of each user and the corresponding downlink spatial ones. The theorem of the arrangement inequalities is adopted to obtain the approximate closed-form solution of the optimal pairing for this convex optimization. Simulation results demonstrate that compared to the existing distributed space-time block coding and coherent combined schemes without SCP, the proposed max-rate SCP plus MRC algorithm achieves appreciable improvements in symbol error rate in medium and high signal-to-noise ratio regimes. The achievable performance gain is due to the use of maxrate SCP.展开更多
In this paper,we introduce the notion of G_(C)-X-injective modules,where X denotes a class of left S-modules and C represents a faithfully semidualizing bimodule.Under the condition that X satisfies certain hypotheses...In this paper,we introduce the notion of G_(C)-X-injective modules,where X denotes a class of left S-modules and C represents a faithfully semidualizing bimodule.Under the condition that X satisfies certain hypotheses,some properties and some equivalent characterizations of G_(C)-X-injective modules are investigated,and we also show that the triple(■,cores■,■)is a weak co-AB-context.As an application,two complete cotorsion pairs and a new model structure in Mod S are given.展开更多
To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.T...To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.This source is based on spontaneous four-wave mixing(SFWM)in a piece of shallow-ridge silicon waveguide.Theoretical analysis shows that the waveguide dispersion could be tailored by adjusting the ridge width,enabling broadband photon pair generation by SFWM across C band and O band.The spontaneous Raman scattering(SpRS)in silicon waveguides is also investigated experimentally.It shows that there are two regions in the spectrum of generated photons from SpRS,which could be used to achieve cross-band photon pair generation.A chip of shallow-ridge silicon waveguide samples with different ridge widths has been fabricated,through which cross-band photon pair generation is demonstrated experimentally.The experimental results show that the source can be achieved using dispersion-optimized shallow-ridge silicon waveguides.This cross-band quantum light source provides a way to develop new fiber-based quantum communication functions utilizing both C band and O band and extends applications of quantum networks.展开更多
Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford prod...Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford products with fixed sequences and compositions.Herein,we report the triethylborane/1,8-diazabicyclo[5.4.0]undec-7-ene(Et_3B/DBU)pair-mediated four-component switchable polymerization of propylene oxide(PO),CO_(2),phthalic anhydride(PA),and racemic lactide(rac-LA),which enables the on-demand synthesis of four different block copolymers,i.e.,poly(propylene phthalate)-b-polylactide(PPE-b-PLA),PPE-b-PLA-b-poly(propylene carbonate)(PPC),PPE-b-PPC-b-PLA,and PPE-b-PPCb-poly(propylene oxide)(PPO),through rationally modulating the Lewis pair(LP)ratio.Core to this protocol is that increasing the loading of Et_(3)B accelerates the ring-opening of PO while impeding the reactivity of rac-LA,thus allowing for fine-tuning of the thermodynamic and kinetic of the switchable polymerization.Therefore,the four polymerization cycles involving PO/PA ring-opening copolymerization(ROCOP),PO/CO_(2) ROCOP,rac-LA ring-opening polymerization(ROP),and PO ROP can be connected and discriminated in precisely programmed manners.展开更多
In this study,electrochemical C-H carboxylation of benzylamines with CO_(2) was reported.This linear paired electrolysis system enables efficient and economical synthesis of value-added α-amino acids(α-AAs) under mi...In this study,electrochemical C-H carboxylation of benzylamines with CO_(2) was reported.This linear paired electrolysis system enables efficient and economical synthesis of value-added α-amino acids(α-AAs) under mild conditions.Various substituted benzylamines containing diverse functional groups and even highly reactive moieties,such as cyano,amide and alkene groups could be successfully transformed to the carboxylated products.Notably,this method proved to be applicable to the late-stage modification of biorelevant compounds,highlighting its potential for synthetic chemistry.Mechanistic studies such as radical trapping experiments,kinetic isotope effect(KIE) tests and cyclic voltammetry(CV) studies provided useful insight into this transformation.展开更多
Achieving non-centrosymmetric(NCS) configurations in ABX3-type hybrid halides remains a critical challenge for nonlinear optical(NLO) materials due to the conflicting requirements of high second-harmonic generation(SH...Achieving non-centrosymmetric(NCS) configurations in ABX3-type hybrid halides remains a critical challenge for nonlinear optical(NLO) materials due to the conflicting requirements of high second-harmonic generation(SHG) response,wide bandgap,and phase-matching capabilities.Herein,we propose a triplesite modulation strategy by synergistically tailoring the A-site cations(2-methylimidazole cation/1-ethyl-3-methylimidazole cation),B-site metals(Sn^(2+)/Pb^(2+)),and X-site halogens(Cl/Br),which effectively disrupts lattice symmetry and enables NCS crystallization.Our results demonstrate a strong SHG response,an expanded optical bandgap and increased birefringence.The optimized compound C_(6)H_(11)N_(2)PbCl_(3) exhibits a moderately strong SHG efficiency of 3.8 × KDP,a wide bandgap(3.87 eV),and enhanced birefringence(0.139@1064 nm),surpassing majority hybrid NLO materials.The innovative anionic framework introduced here broadens the scope of hybrid NLO crystals,facilitating the integration of various aromatic heterocyclic cations.This research provides a robust strategic framework for the development of advanced NLO materials.展开更多
Transition metal selenides as sodium-ion hybrid capacitor(SIHC)anodes still suffer from amorphization difficulties and capacity degradation triggered by polyselenide dissolution.Herein,an atomistic amorphous strategy ...Transition metal selenides as sodium-ion hybrid capacitor(SIHC)anodes still suffer from amorphization difficulties and capacity degradation triggered by polyselenide dissolution.Herein,an atomistic amorphous strategy is proposed to construct adjacent Nb-Nb diatomic pairs with Se/O-coordination(Se4-Nb2-O2)in N-doped carbon-confined amorphous selenide clusters(a-Nb-Se/O@NC).Synergistic carbon confinement and hydrothermal oxygenation induce amorphization of Nb–Se bonds,eliminating crystalline rigidity while creating isotropic dual-ion transport channels and high-density active sites enriched with dangling bonds,thereby enhancing structural integrity and Na+storage capacity.The unique Se/O-coordinated Nb-Nb diatomic configuration establishes an electron-delocalized system,where the low electronegativity of Se counterbalances electron withdrawal from coordinated O at Nb centers.These strengthen d-p orbital hybridization,reduce Na+adsorption energy,and optimize charge transfer pathways and reaction kinetics in the amorphous clusters.Electrochemical tests reveal that the a-Nb-Se/O@NC anode delivers a high reversible capacity of 312.57 mAh g^(−1)and exceptional cyclic stability(103%capacity retention)after 5000 cycles at 10.0 A g^(−1).Assembled SIHCs achieve outstanding energy/power densities(207.1 Wh kg^(−1)/18966 W kg^(−1)),surpassing most amorphous and crystalline counterparts.This work provides methodological insights for the design of electrodes in high-power storage devices through atomic modulation and electronic optimization of amorphous selenides.展开更多
Following over 20 years of research,a direct measurement of the QGP temperature has been achieved at Relativistic Heavy-Ion Collider(RHIC),free from the blue-shift effect and contamination from strong interactions.Thi...Following over 20 years of research,a direct measurement of the QGP temperature has been achieved at Relativistic Heavy-Ion Collider(RHIC),free from the blue-shift effect and contamination from strong interactions.This viewpoint discusses a recent measurement of the QGP temperature at different stages at the Solenoidal Tracker at RHIC(STAR),which used e^(+)e^(-)pairs as penetrating probes.展开更多
In the area of secure Web information system, mutual authentication and key agreement are essential between Web clients and servers. An efficient certificateless authenticated key agreement protocol for Web client/ser...In the area of secure Web information system, mutual authentication and key agreement are essential between Web clients and servers. An efficient certificateless authenticated key agreement protocol for Web client/server setting is proposed, which uses pairings on certain elliptic curves. We show that the newly proposed key agreement protocol is practical and of great efficiency, meanwhile, it satisfies every desired security require ments for key agreement protocols.展开更多
Alloying can make conventional metals reach ultra-high strength,but this usually comes at dramatic loss of toughness.In this work,a desirable strength–toughness combination in high-strength low-alloy steel achieved v...Alloying can make conventional metals reach ultra-high strength,but this usually comes at dramatic loss of toughness.In this work,a desirable strength–toughness combination in high-strength low-alloy steel achieved via trace carbon addition.The significance of carbon in tailoring variant pairing and tuning impact toughness was elucidated from the perspective of crystallography and thermodynamics.As the carbon content increases,the packets and blocks are refined,and the-40 impact toughness improves.The enhancement of impact toughness results from the higher density of block boundaries,and the fracture mode shifts from brittle fracture to ductile–brittle combined fractures,then to ductile fracture due to the increased carbon.Increasing the carbon content would lower the martensite start temperature(M_S)temperature and driving force for martensitic transformation,and increase the strength of austenite matrix,which in turn contributes to producing more V1/V2 variant pairs to accommodate the transformation strain.展开更多
The idea behind a (t, n) threshold blind signature is that a user can ask at least t out of n players of a group to cooperate to generate a signature for a message without revealing its content. This paper first prese...The idea behind a (t, n) threshold blind signature is that a user can ask at least t out of n players of a group to cooperate to generate a signature for a message without revealing its content. This paper first presents a new blind signature scheme from Weil pairing on elliptic curves. Based on this scheme, a threshold blind signature scheme is proposed. It is efficient and has the security properties of robustness and unforgeability. In the proposed scheme, the group manger is introduced to take the role of distributing the group secret key to each player. However, he cannot forge the players to generate partial blind signatures (Each partial blind signature depends on not only the secret key of the player, but also a random number the player picks). Compared with a threshold signature with a trusted third party, its advantage is obvious; Compared with a threshold signature without a trusted third party, it is more simple and efficient.展开更多
Signcryption is a cryptographic primitive that performs signature and encryption simultaneously, at lower computational costs and communication overheads than the signature-then- encryption approach. In this paper, we...Signcryption is a cryptographic primitive that performs signature and encryption simultaneously, at lower computational costs and communication overheads than the signature-then- encryption approach. In this paper, we propose an efficient multi-recipient signcryption scheme based on the bilinear pairings, which broadcasts a message to multiple users in a secure and authenticated manner. We prove its semantic security and unforgeability under the Gap Diffie-Hellman problem assumption in the random oracle model. The proposed scheme is more efficient than re-signcrypting a message n times using a signcryption scheme in terms of computational costs and communication overheads.展开更多
We argue that traditional identity-based systems from pairings seem unsuitable for designing group signature schemes due to the problem of key escrow. In this paper we first propose new ID-based public key systems wit...We argue that traditional identity-based systems from pairings seem unsuitable for designing group signature schemes due to the problem of key escrow. In this paper we first propose new ID-based public key systems without trusted PKG (Private Key Generator) from bilinear pairings. In our new ID-based systems, if the dishonest PKG impersonates an honest user to communicate with others, the user can provide a proof of treachery of the PKG afterwards, which is similar to certificate-based systems. Therefore, our systems reach the Girault’s trusted level 3. We then propose a group signature scheme under the new ID-based systems, the security and performance of which rely on the new systems. The size of the group public key and the length of the signature are independent on the numbers of the group.展开更多
基金supported by the National Natural Science Foundation of China[Grant Nos.U23A2073(P.Z.)and 11547034(H.Z.)].
文摘The measurement of the pairing gap is crucial for investigating the physical properties of superconductors or superfluids.We propose a strategy to measure the pairing gap through the dynamical excitations.With the random phase approximation(RPA),we study the dynamical excitations of a two-dimensional attractive Fermi-Hubbard model by calculating its dynamical structure factor.Two distinct collective modes emerge:a Goldstone phonon mode at transferred momentum q=[0,0]and a roton mode at q=[p,p].The roton mode exhibits a sharp molecular peak in the low-energy regime.Notably,the area under the roton molecular peak scales with the square of the pairing gap,which holds even in three-dimensional and spin-orbit coupled(SOC)optical lattices.This finding suggests an experimental approach to measure the pairing gap in lattice systems by analyzing the dynamical structure factor at q=[p,p].
基金supported by the National Natural Science Foundation of China (Grant No. 12447103)financial support from the MERIT-WINGS course provided by the University of Tokyo+10 种基金the Fellowship for Integrated Materials Science and Career Development provided by the Japan Science and Technology Agencysupport from the computational resource of Wisteria/BDEC-01 provided by Information Technology Center, the University of Tokyo, for the Monte Carlo simulationthe support by the National Natural Science Foundation of China (Grant No. 12404275)the Fundamental Research Program of Shanxi Province (Grant No. 202403021212015)support from the Würzburg-Dresden Cluster of Excellence on Complexity and Topology in Quantum Matter-ct.qmat (EXC 2147, Project No. 390858490)supported by the National Natural Science Foundation of China (Grant No. 12274289)the National Key R&D Program of China (Grant Nos. 2022YFA1402702 and 2021YFA1401400)the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0301902)Yangyang Development Fund, and Startup Funds from SJTUsupported by the National Key R&D Program of China (Grant No. 2023YFA1407300)the National Natural Science Foundation of China (Grant No. 12047503)。
文摘Recent various experiments have provided evidence supporting the emergence of loop-current order in kagome metals. Particularly superconductivity in AV_(3)Sb_(5) is significantly enhanced when this charge order is suppressed by pressure or doping. Distinct from magnetic order, loop-current order does not couple directly to spin and thus whether such fluctuations can enhance superconductivity remains elusive. We design a sign problem-free bilayer kagome model coupled to quantum Ising spins through bond currents and perform determinant quantum Monte Carlo simulations to explore single-particle properties and superconductivity arising from 2 × 2 loopcurrent fluctuations. We find that this loop-current order induces intriguing band folding, band broadening,and gap opening around saddle points. Remarkably, our pairing susceptibility analysis identifies a dominant enhancement of superconductivity due to loop-current fluctuations, with the dominant pairing being the chiral d-wave channel. This pairing primarily occurs within the intra-sublattice channel and involves third nearestneighbor sites, attributed to the unique sublattice texture associated with van Hove singularities. We also discuss potential experimental implications for kagome superconductors.
基金financed by the grant from the Fundamental Research Funds for the Central Universities (No. 2019-JYB-TD004)。
文摘The infection of SARS-CoV-2 has triggered the COVID-19 pandemic. In addition to the fever and respiratory symptoms in the process of coronavirus infections, gastrointestinal symptoms, especially diarrhea, are prominent features of its acute infection and long COVID. The associations between the lung and large intestine have been demonstrated by Western medicine in aspects such as tissue origin, microflora homeostasis, mucosal immunity, renin-angiotensin system(RAS) and autonomic nervous system as well, which are considered as the evidence of material basis and potential regulatory mechanisms for “gutlung crosstalk(肺肠串扰)” in COVID-19. We have noticed that probiotics and other preparations can regulate the intestines, and further treat COVID-19 with effective and gratifying results. In the system of traditional Chinese medicine(TCM), there's a term of “exterior-interior pairing of the lung and large intestine(肺与大肠相表里)”, showing an interconnection of the lung and the bowels. “Exterior-interior pairing of the lung and large intestine” is an important part of the theory of visceral activities proposed by ancient physicians through a long-term observation and practice. It's considered that “lung” and “large intestine” are interconnected and mutually exterior-interior in the normal physical activities and the disease development, providing a theoretical basis for treating lung diseases and bowel diseases from the perspective of overall concept. The study aims to compare the term of “exterior-interior pairing of the lung and large intestine” in TCM and “gut-lung crosstalk” in Western medicine regarding the development of COVID-19 and its intestinal symptoms, and provide more ideas for diagnosing and treating lung and bowel related diseases.
文摘The stable Bardeen-Schrieffer-Cooper(BCS)pairing state of a bosonic system has long been sought theoretically and experimentally.Here we propose that a stable BCS state of bosons can be realized in a binary Bose gas with s-wave intra-species repulsion and an inter-species attraction in the mean-field-stable region.We find that above the Bose-Einstein condensation(BEC)transition temperature,there is a phase transition from the normal state to a BCS state driven by interspecies pairing.When the temperature decreases,another phase transition from the BCS state to a mixed state featuring both atomic BEC and inter-species pairing occurs.As the temperature is further lowered,the mixed state is eventually taken over by the pure BEC state.We present the phase diagram of this system and discuss its experimental implications.
文摘The combined lines having both phKL and Ph2-deficiency were obtained in the genetic background of common wheat (Triticum aestivum L.) landrace. These lines had normal fertility. In the wheat combined lines X Aegilops variabilis Eig. (or rye), a significant increase in the chiasmata of homoeologous pairing was shown by the phKL+Ph2(-) plants with respect to their phKL+Ph2 sibs, which indicates that Ph2-deficiency and phKL showed an additive effect on promoting pairing. The effects were shown in the increment of rod bivalents, ring bivalents and trivalents and reduction of univalents, of which, reduction of univalents was mainly due to the increment of rod bivalents. The combined lines are probably more desirable materials for alien gene transferring than phKL or Ph2(-) lines alone. In comparison with that of ph1b X Ae. variabilis (or rye), phKL+Ph2(-) X Ae. variabilis (or rye) show higher (or similar) numbers of rod bivalents, while the total chromosome pairing level significantly reduced that ascribed to the decrement in ring bivalents and multivalents. These results probably indicate the different genetic mechanisms for Ph1 and Ph2 or phKL on controlling homoeologous pairing.
基金The Open Research Fund of National Mobile Communications Research Laboratory of Southeast University(No.2013D02)the Open Research Fund of National Key Laboratory of Electromagnetic Environment of China Research Institute of Radio Wave Propagation(No.201500013)the National Natural Science Foundation of China(No.61271230,61472190)
文摘To improve the reliable performance of information transmission in cooperative relay networks, the scheme of the max-rate spatial channel pairing （SCP） based on maximum ratio combining （MRC） is proposed. The scheme includes three steps： channel phase cancellation, MRC, and SCP. Eventually, the solution of the scheme is modeled as convex optimization. The objective function of the optimization problem is to maximize the transmission rate and the optimization variable is the strategy of pairing between the uplink spatial sub-channels of each user and the corresponding downlink spatial ones. The theorem of the arrangement inequalities is adopted to obtain the approximate closed-form solution of the optimal pairing for this convex optimization. Simulation results demonstrate that compared to the existing distributed space-time block coding and coherent combined schemes without SCP, the proposed max-rate SCP plus MRC algorithm achieves appreciable improvements in symbol error rate in medium and high signal-to-noise ratio regimes. The achievable performance gain is due to the use of maxrate SCP.
文摘In this paper,we introduce the notion of G_(C)-X-injective modules,where X denotes a class of left S-modules and C represents a faithfully semidualizing bimodule.Under the condition that X satisfies certain hypotheses,some properties and some equivalent characterizations of G_(C)-X-injective modules are investigated,and we also show that the triple(■,cores■,■)is a weak co-AB-context.As an application,two complete cotorsion pairs and a new model structure in Mod S are given.
基金supported by the Quantum Science and Technology-National Science and Technology Major Project (Grant No.2024ZD0302502 for WZ)the National Natural Science Foundation of China(Grant No.92365210 for WZ)+1 种基金Tsinghua Initiative Scientific Research Program (for WZ)the project of Tsinghua University-Zhuhai Huafa Industrial Share Company Joint Institute for Architecture Optoelectronic Technologies (JIAOT,for YH)。
文摘To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.This source is based on spontaneous four-wave mixing(SFWM)in a piece of shallow-ridge silicon waveguide.Theoretical analysis shows that the waveguide dispersion could be tailored by adjusting the ridge width,enabling broadband photon pair generation by SFWM across C band and O band.The spontaneous Raman scattering(SpRS)in silicon waveguides is also investigated experimentally.It shows that there are two regions in the spectrum of generated photons from SpRS,which could be used to achieve cross-band photon pair generation.A chip of shallow-ridge silicon waveguide samples with different ridge widths has been fabricated,through which cross-band photon pair generation is demonstrated experimentally.The experimental results show that the source can be achieved using dispersion-optimized shallow-ridge silicon waveguides.This cross-band quantum light source provides a way to develop new fiber-based quantum communication functions utilizing both C band and O band and extends applications of quantum networks.
基金financially supported by National Key R&D Program Young Scientists Project(No.2023YFC3903100)the National Natural Science Foundation of China(No.22322503)analytical and testing assistance from the Analysis and Testing Center of HUST。
文摘Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford products with fixed sequences and compositions.Herein,we report the triethylborane/1,8-diazabicyclo[5.4.0]undec-7-ene(Et_3B/DBU)pair-mediated four-component switchable polymerization of propylene oxide(PO),CO_(2),phthalic anhydride(PA),and racemic lactide(rac-LA),which enables the on-demand synthesis of four different block copolymers,i.e.,poly(propylene phthalate)-b-polylactide(PPE-b-PLA),PPE-b-PLA-b-poly(propylene carbonate)(PPC),PPE-b-PPC-b-PLA,and PPE-b-PPCb-poly(propylene oxide)(PPO),through rationally modulating the Lewis pair(LP)ratio.Core to this protocol is that increasing the loading of Et_(3)B accelerates the ring-opening of PO while impeding the reactivity of rac-LA,thus allowing for fine-tuning of the thermodynamic and kinetic of the switchable polymerization.Therefore,the four polymerization cycles involving PO/PA ring-opening copolymerization(ROCOP),PO/CO_(2) ROCOP,rac-LA ring-opening polymerization(ROP),and PO ROP can be connected and discriminated in precisely programmed manners.
基金Financial support from National Key R&D Program of China (No.2023YFA1507203)National Natural Science Foundation of China (Nos.22371149 and 22188101)+3 种基金the Fundamental Research Funds for the Central Universities (No.63224098)Frontiers Science Center for New Organic Matter,Nankai University (No.63181206)Nankai University are gratefully acknowledgedthe Haihe Laboratory of Sustainable Chemical Transformations for financial support。
文摘In this study,electrochemical C-H carboxylation of benzylamines with CO_(2) was reported.This linear paired electrolysis system enables efficient and economical synthesis of value-added α-amino acids(α-AAs) under mild conditions.Various substituted benzylamines containing diverse functional groups and even highly reactive moieties,such as cyano,amide and alkene groups could be successfully transformed to the carboxylated products.Notably,this method proved to be applicable to the late-stage modification of biorelevant compounds,highlighting its potential for synthetic chemistry.Mechanistic studies such as radical trapping experiments,kinetic isotope effect(KIE) tests and cyclic voltammetry(CV) studies provided useful insight into this transformation.
基金supported by the National Natural Science Foundation of China (No.22275052)Department of Science and Technology of Hubei Province (Nos.2025AFA111 and 2024CSA076)。
文摘Achieving non-centrosymmetric(NCS) configurations in ABX3-type hybrid halides remains a critical challenge for nonlinear optical(NLO) materials due to the conflicting requirements of high second-harmonic generation(SHG) response,wide bandgap,and phase-matching capabilities.Herein,we propose a triplesite modulation strategy by synergistically tailoring the A-site cations(2-methylimidazole cation/1-ethyl-3-methylimidazole cation),B-site metals(Sn^(2+)/Pb^(2+)),and X-site halogens(Cl/Br),which effectively disrupts lattice symmetry and enables NCS crystallization.Our results demonstrate a strong SHG response,an expanded optical bandgap and increased birefringence.The optimized compound C_(6)H_(11)N_(2)PbCl_(3) exhibits a moderately strong SHG efficiency of 3.8 × KDP,a wide bandgap(3.87 eV),and enhanced birefringence(0.139@1064 nm),surpassing majority hybrid NLO materials.The innovative anionic framework introduced here broadens the scope of hybrid NLO crystals,facilitating the integration of various aromatic heterocyclic cations.This research provides a robust strategic framework for the development of advanced NLO materials.
基金supported by the National Natural Science Foundation of China(Grant No.52573299)the Natural Science Foundation of Jiangxi province(No.20242BAB25223,20232BCJ23025,20232BCJ25040,20232BAB214024)the Special Funding Program for Graduate Student Innovation of Jiangxi Province(No.YC2024-S594).
文摘Transition metal selenides as sodium-ion hybrid capacitor(SIHC)anodes still suffer from amorphization difficulties and capacity degradation triggered by polyselenide dissolution.Herein,an atomistic amorphous strategy is proposed to construct adjacent Nb-Nb diatomic pairs with Se/O-coordination(Se4-Nb2-O2)in N-doped carbon-confined amorphous selenide clusters(a-Nb-Se/O@NC).Synergistic carbon confinement and hydrothermal oxygenation induce amorphization of Nb–Se bonds,eliminating crystalline rigidity while creating isotropic dual-ion transport channels and high-density active sites enriched with dangling bonds,thereby enhancing structural integrity and Na+storage capacity.The unique Se/O-coordinated Nb-Nb diatomic configuration establishes an electron-delocalized system,where the low electronegativity of Se counterbalances electron withdrawal from coordinated O at Nb centers.These strengthen d-p orbital hybridization,reduce Na+adsorption energy,and optimize charge transfer pathways and reaction kinetics in the amorphous clusters.Electrochemical tests reveal that the a-Nb-Se/O@NC anode delivers a high reversible capacity of 312.57 mAh g^(−1)and exceptional cyclic stability(103%capacity retention)after 5000 cycles at 10.0 A g^(−1).Assembled SIHCs achieve outstanding energy/power densities(207.1 Wh kg^(−1)/18966 W kg^(−1)),surpassing most amorphous and crystalline counterparts.This work provides methodological insights for the design of electrodes in high-power storage devices through atomic modulation and electronic optimization of amorphous selenides.
文摘Following over 20 years of research,a direct measurement of the QGP temperature has been achieved at Relativistic Heavy-Ion Collider(RHIC),free from the blue-shift effect and contamination from strong interactions.This viewpoint discusses a recent measurement of the QGP temperature at different stages at the Solenoidal Tracker at RHIC(STAR),which used e^(+)e^(-)pairs as penetrating probes.
基金Supported bythe National Natural Science Foundationof China (60225007 ,60572155) the Science and Technology ResearchProject of Shanghai (04DZ07067)
文摘In the area of secure Web information system, mutual authentication and key agreement are essential between Web clients and servers. An efficient certificateless authenticated key agreement protocol for Web client/server setting is proposed, which uses pairings on certain elliptic curves. We show that the newly proposed key agreement protocol is practical and of great efficiency, meanwhile, it satisfies every desired security require ments for key agreement protocols.
基金financially supported by the National Key Research and Development Program of China(No.2017YFB0304800)financial support of China Scholarship Council(award for one year visiting in Northwestern University in USA,No.201706465056)。
文摘Alloying can make conventional metals reach ultra-high strength,but this usually comes at dramatic loss of toughness.In this work,a desirable strength–toughness combination in high-strength low-alloy steel achieved via trace carbon addition.The significance of carbon in tailoring variant pairing and tuning impact toughness was elucidated from the perspective of crystallography and thermodynamics.As the carbon content increases,the packets and blocks are refined,and the-40 impact toughness improves.The enhancement of impact toughness results from the higher density of block boundaries,and the fracture mode shifts from brittle fracture to ductile–brittle combined fractures,then to ductile fracture due to the increased carbon.Increasing the carbon content would lower the martensite start temperature(M_S)temperature and driving force for martensitic transformation,and increase the strength of austenite matrix,which in turn contributes to producing more V1/V2 variant pairs to accommodate the transformation strain.
基金Supported by the National 973 Project of China(No.G1999035803)the National Natural Science Foundation of China (No.60373104)the National 863 Project of China (No.2002AA143021)
文摘The idea behind a (t, n) threshold blind signature is that a user can ask at least t out of n players of a group to cooperate to generate a signature for a message without revealing its content. This paper first presents a new blind signature scheme from Weil pairing on elliptic curves. Based on this scheme, a threshold blind signature scheme is proposed. It is efficient and has the security properties of robustness and unforgeability. In the proposed scheme, the group manger is introduced to take the role of distributing the group secret key to each player. However, he cannot forge the players to generate partial blind signatures (Each partial blind signature depends on not only the secret key of the player, but also a random number the player picks). Compared with a threshold signature with a trusted third party, its advantage is obvious; Compared with a threshold signature without a trusted third party, it is more simple and efficient.
基金Supported by the National Natural Science Foundation of China (60473029)
文摘Signcryption is a cryptographic primitive that performs signature and encryption simultaneously, at lower computational costs and communication overheads than the signature-then- encryption approach. In this paper, we propose an efficient multi-recipient signcryption scheme based on the bilinear pairings, which broadcasts a message to multiple users in a secure and authenticated manner. We prove its semantic security and unforgeability under the Gap Diffie-Hellman problem assumption in the random oracle model. The proposed scheme is more efficient than re-signcrypting a message n times using a signcryption scheme in terms of computational costs and communication overheads.
基金Supported by National Natural Science Foundation of China (No.60503006 and No.60403007) and Natural Science Foundation of Guangdong, China (No. 04205407).
文摘We argue that traditional identity-based systems from pairings seem unsuitable for designing group signature schemes due to the problem of key escrow. In this paper we first propose new ID-based public key systems without trusted PKG (Private Key Generator) from bilinear pairings. In our new ID-based systems, if the dishonest PKG impersonates an honest user to communicate with others, the user can provide a proof of treachery of the PKG afterwards, which is similar to certificate-based systems. Therefore, our systems reach the Girault’s trusted level 3. We then propose a group signature scheme under the new ID-based systems, the security and performance of which rely on the new systems. The size of the group public key and the length of the signature are independent on the numbers of the group.
