The application of conventional manganese dioxide(MnO_(2))materials in sodium-ion supercapacitors(Na-SCs)is considerably limited by their low conductivity and structural instability.Biomimetic morphology engineering c...The application of conventional manganese dioxide(MnO_(2))materials in sodium-ion supercapacitors(Na-SCs)is considerably limited by their low conductivity and structural instability.Biomimetic morphology engineering can optimize the electrochemical performance of MnO_(2).Here,based on the metal-organic frameworks(MOFs)-derived method and electrochemical reconstruction,a coral-like MnO_(2)structure integrated with a functional nitrogen-doped carbon(NC)coating is designed for Na-SC application.The bioinspired coral-like structure captures numerous electrolyte ions and increases the Na+concentration on the electrode surface,which is beneficial for optimizing the Na+transport pathway and accelerating the electrode reaction kinetics.Moreover,the coral-like crosslinked structure effectively enhances the mechanical properties,enabling the maintenance of the structure of MnO_(2)-based electrodes during long-term operation.Furthermore,in/ex-situ characterizations are performed to elucidate the mechanism of lattice transformation during electrochemical phase reconstruction.Additionally,the theoretical calculation and simulation results reveal the ion/electron dynamics in the fabricated electrode.The prepared electrode demonstrates excellent capacitance storage ability(340.7 F g^(−1)at 0.5 A g^(−1))and cycling stability(85.1%capacitance retention after 10,000 cycles).The assembled hybrid device exhibits exceptional life-span(82.0%capacitance retention after 10,000 cycles)and exceptional energy density(36.5 Wh kg^(−1)).This study provides a reliable biomimetic morphology design strategy for MnO_(2)cathodes,paving the way for the fabrication of high-performance Na-SCs.展开更多
The large volume expansion and rapid capacity attenuation of tin-based electrodes are the main factors limiting their commercial application.The reasonable design of electrode material structure is particularly import...The large volume expansion and rapid capacity attenuation of tin-based electrodes are the main factors limiting their commercial application.The reasonable design of electrode material structure is particularly important for improving its electrochemical performance.Herein,phosphorus-modified graphene encapsulated Sn_(6)O_(4)(OH)_(4)nanoparticles composite(P-Sn_(6)O_(4)(OH)_(4)@RGO)with crystalline-amorphous heterostructure has been successfully designed and prepared.The design of crystalline-amorphous structure has largely enhanced the active sites,and the construction of a graphene encapsulation structure has greatly alleviated volume expansion.Notably,P-Sn_(6)O_(4)(OH)_(4)@RGO obtained an excellent high-rate longterm cycling performance for lithium-ion batteries anode,reaching a high specific capacity of 970 m Ah/g at 1.0 A/g after 1450 cycles.This work demonstrates that restructuring the electrode material's structure and phase through phosphorus modification can effectively improve the electrochemical performance of tin-based electrode materials.展开更多
Additively manufactured Ti-6 Al-4 V lattice structures have found important niche applications. However, they often show insufficient compressive ductility or insufficient structural integrity. In this study,a batch o...Additively manufactured Ti-6 Al-4 V lattice structures have found important niche applications. However, they often show insufficient compressive ductility or insufficient structural integrity. In this study,a batch of 45 octahedral Ti-6 Al-4 V lattice structures was manufactured in three different strut diameters(0.5, 1.0, 1.5 mm) by selective electron beam melting(SEBM). The influence of post-SEBM annealing on the compressive deformation characteristics of the lattice structure was investigated. The as-built Ti-6 Al-4 V lattices fragmented when the compressive strain reached 13%–23% depending on strut diameter.Annealing at 950?C(β transus temperature: 995?C) only slightly improved the compressive ductility of the lattice structures. However, annealing at 1050?C(β-annealing) fundamentally changed the compressive deformation mode of the lattice structures. The resultant compressive stress-strain curve was featured by a long smooth plateau and no facture occurred even after significant densification of the lattice structure had taken place(>50% of compressive strain).展开更多
Pd modified electrodes possess problems such as easy agglomeration and low electrolytic ability,and the use of manganese dioxide(MnO_(2)) to facilitate Pd reduction of organic pollutants is just started.However,there ...Pd modified electrodes possess problems such as easy agglomeration and low electrolytic ability,and the use of manganese dioxide(MnO_(2)) to facilitate Pd reduction of organic pollutants is just started.However,there is still a limited understanding of how to match the Pd load and MnO_(2) to realize optimal dechlorination efficiency at minimum cost.Here,a Pd/MnO_(2)/Ni foam cathode was successfully fabricated and applied for the efficient electrochemical dechlorination of 2,4,6-trichlorophenol(2,4,6-TCP).The optimal electrocatalytic hydrodechlorination(ECH)performance with 2,4,6-TCP dechlorination efficiency(92.58%in 180 min)was obtained when the concentration of PdCl_(2) precipitation was 1 mmol/L,the deposition time of MnO_(2) was 300 s and cathode potential was-0.8 V.Performance influenced by the exogenous factors(e.g.,initial pH and coexisted ions)were further investigated.It was found that the neutral pH was the most favorable for ECH and a reduction in dechlorination efficiency(6%~47.6%)was observed in presence of 5 mmol/L of NO_(2)^(-),NO_(3)^(-),S^(2-)or SO_(3)^(2-).Cyclic voltammetry(CV)and quenching experiments verified the existence of three hydrogen species on Pd surface,including adsorbed atomic hydrogen(H^(*)_(ads)),absorbed atomic hydrogen(H^(*)_(abs)),and molecular hydrogen(H_(2)).And the introduction of MnO_(2)promoted the generation of atomic H^(*).Only adsorbed atomic hydrogen(H^(*)_(ads)) was confirmed that it truly facilitated the ECH process.Besides H^(*)_(ads) induced reduction,the direct reduction by cathode electrons also participated in the 2,4,6-TCP dechlorination process.Pd/MnO_(2)/Ni foam cathode shows excellent dechlorination performance,fine stability and recyclable potential,which provides strategies for the effective degradation of persistent halogenated organic pollutants in groundwater.展开更多
Some approaches to measure parallel 6-degree of freedom platform's posturestatically and to calibrate the platform's actual structural parameters by measuring a series of theplatform's varying postures are...Some approaches to measure parallel 6-degree of freedom platform's posturestatically and to calibrate the platform's actual structural parameters by measuring a series of theplatform's varying postures are studied. In the case where high posture accuracy is requiredrelatively, to obtain the platform's actual structural parameters is very important. Threedimensions measurement with 2 theodolites are used to obtain the platform's postures statically andNewton iterative method is adopted to calibrate structural parameters. Some measures taken in themeasurement and the calibration are discussed in detail. And the experiment results of theplatform's posture control before and after the calibration are given. The results show that theplatform's posture control accuracy after the calibration is improved notably.展开更多
Noroviruses(NoVs)are the primary cause of acute gastroenteritis worldwide.Histo-blood group antigens(HBGAs)are receptors or attachment factors that affect the prevalence and host susceptibility of NoVs.GII.6 NoV is on...Noroviruses(NoVs)are the primary cause of acute gastroenteritis worldwide.Histo-blood group antigens(HBGAs)are receptors or attachment factors that affect the prevalence and host susceptibility of NoVs.GII.6 NoV is one of the predominant genotypes in humans,which recognizes the type ABO secretor of HBGAs.However,the structural basis of GII.6 NoV's interaction with HBGAs receptors remains elusive.In this study,we investigated the binding features of the GII.6 strain to HBGAs using saliva-and glycan-ELISA assays and characterized the molecular basis of the GII.6 virus that recognizes H disaccharide.We showed that the GII.6 P domain recognized some A and O secretor's saliva samples,most B secretor's saliva samples,and H disaccharide antigen,but did not bind non-secretors’saliva.Further,we determined the crystal structures of GII.6 and its complex with H disaccharides at 1.7Å,revealing that the P domain of GII.6 shares the conventional binding interface and mode of GII HBGAs.Single residue mutations at the GII.6-H binding sites could inhibit the binding of GII.6 to HBGAs,demonstrating that the interaction residues were crucial in maintaining NoV-glycan integrity.Finally,structural and sequence analyses showed that the major residues of the GII.6-H interaction were conserved among NoVs in the GII genogroup.Taken together,our study characterized the functional and structural features of GII.6 that allow it to interact with HBGAs,and shed light on NoV evolution,epidemiology,and anti-viral drug development.展开更多
A polynuclear complex [Cd（endc）（H20）]n·nH2O （endc = endo-norbornene-cis- 5,6-dicarboxylate anion） has been synthesized by the hydrothermal reaction of cadmium nitrate tetrahydrate with endo-norbornene-cis-5...A polynuclear complex [Cd（endc）（H20）]n·nH2O （endc = endo-norbornene-cis- 5,6-dicarboxylate anion） has been synthesized by the hydrothermal reaction of cadmium nitrate tetrahydrate with endo-norbornene-cis-5,6-dicarboxylic acid in 1：1 molar ratio, and structurally characterized by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/c with α = 1.16471（7）, b = 0.95334（7）, c = 0.91109（9） nm, Z= 4, V= 1.01035（14） nm^3, D, = 2.160 g/cm^3,μ = 2.172 mm^-1, F（000） = 648, R = 0.0302 and wR = 0.0752. According to structural analysis, each Cd（II） ion is coordinated to six O atoms from three endc anions and one water molecule, giving a distorted octahedral geometry. Two- dimensional layer arrangement of the title complex is constructed from the bridging nature of endc. It is worth notice that adjacent two-dimensional layers are joined together to form a three-dimensional supramolecular framework via intermolecular hydrogen bonding interactions.展开更多
Although pseudocapacitive manganese dioxide(MnO_(2))integrates the high-power merit of carbonaceous materials with the high-energy merit of battery-type materials,it still has a long way to go in achieving a more sati...Although pseudocapacitive manganese dioxide(MnO_(2))integrates the high-power merit of carbonaceous materials with the high-energy merit of battery-type materials,it still has a long way to go in achieving a more satisfactory balance of higher energy and power density,and in decoupling the relationship of structural characteristics with energy storage performance.To realize such goals,a bottom-up[WO_(6)]-perturbed[MnO_(6)]assembly strategy has been developed here due to their similar structure,yet mismatched lattice parameters.This facile protocol is capable of finely controlling the morphology and crystal structure of MnO_(2)by adjusting its internal[WO_(6)]concentration.Therefore,the as-prepared W_xMnO_(2)is treated as an ideal platform to scrutinize the correlations of the structure with the energy storage performance.The operando Raman spectra and finite element analysis have fully demonstrated the superiority of the locally ordered defects-enriched structure of W_(0.02)-MnO_(2),which could reach a favorable balance between the ion diffusion equilibrium time and the number of active sites.As a result,the W_(0.02)-MnO_(2)is able to deliver a high capacitance of 292 F·g^(-1)at a current density of 1 A·g^(-1)and a remarkable rate performance with a 60%capacity retention at a current density of 50 A·g^(-1).The further unveiled structure-performance relationship provides a guideline for the design of better pseudocapacitive energy storage devices.展开更多
Structure model of charge-ordered La_0.33 Ca_0.67 MnO_3, perovskite is one of current focused study in condensed matter physics. There are great discrepancies in previous studies in this field. Our transmission electr...Structure model of charge-ordered La_0.33 Ca_0.67 MnO_3, perovskite is one of current focused study in condensed matter physics. There are great discrepancies in previous studies in this field. Our transmission electron microscopy study confirms Wigner crystal model with transverse displacement and is not consisent with the hi-stripe model with longitudinal displacement. We observed incommensurate modulation and anti-phase domains with a displacement vector a_co/3 in charge--ordered La_0.33 Ca_0.67 MnO_3, perovskite.展开更多
In situ Raman spectroscopy and x-ray diffraction measurements are used to explore the structural stability of CaB6 at high pressures and room temperature. The results show no evidence of structural phase transitions u...In situ Raman spectroscopy and x-ray diffraction measurements are used to explore the structural stability of CaB6 at high pressures and room temperature. The results show no evidence of structural phase transitions up to at least 40 GPa.The obtained equation of state with smooth pressure dependencies yields a zero-pressure isothermal bulk modulus B0=170(5) GPa, which agrees well with the previous measurements. The frequency shifts for A1g, Eg, and T2g vibrational modes of polycrystalline CaB6 are obtained with pressure uploading. As the pressure increases, all the vibration modes have smooth monotonic pressure dependence. The Gr¨uneisen parameter of Eg modes is the largest, indicating its largest dependence on the volume of a crystal lattice.展开更多
The exploration of the appropriate red phosphor with good luminescence properties is an important issue in the development of current white light-emitting diode(WLED) devices. Transition metal Mn-doped compounds are f...The exploration of the appropriate red phosphor with good luminescence properties is an important issue in the development of current white light-emitting diode(WLED) devices. Transition metal Mn-doped compounds are fascinating luminescent materials. Herein, we performed a systematic theoretical study of the microstructure and optical properties of K_2TiF_6:Mn^(4+) using the CALYPSO structure search method in combination with first-principles calculations. We uncovered a novel structure of K_2TiF_6:Mn^(4+) with space group P-3m1 symmetry, where the impurity Mn_(4+) ions are accurately located at the center of the MnF_6 octahedra. Based on our developed complete energy matrix diagonalization(CEMD)method, we calculated transition lines for ~2E_g →~4A_2,~4A_2→~4T_2, and^4A_2→T2at 642 nm, 471 nm, and 352 nm,respectively, which are in good agreement with the available experimental data. More remarkably, we also found another transition(~4A_2→~2T_2) that lies at 380 nm, which should be a promising candidate for laser action.展开更多
The BZ19-6 deep buried-hill structural belt in the southwest of Bozhong Sag,Bohai Bay Basin,is a newly discovered super-giant oil and gas bearing area.The study on its reservoirs is still in the early stage,and the ch...The BZ19-6 deep buried-hill structural belt in the southwest of Bozhong Sag,Bohai Bay Basin,is a newly discovered super-giant oil and gas bearing area.The study on its reservoirs is still in the early stage,and the characteristics and control factors of reservoir development are not understood deeply.In this paper,cores,sidewall cores,rock sections were analyzed and described.Then,based on regional structural setting,mud logging and logging data,the buried-hill reservoirs in this area were analyzed from the aspects of petrological characteristics,reservoir space types and physical properties,the inherent factors influencing the development of the reservoirs were discussed,and distribution laws of the reservoirs were investigated.And the following research results were obtained.First,the deep buried-hill reservoirs of this belt are a pan-buried hill reservoir system composed of the Palaeocene-Eocene Kongdian Fm glutenite in the upper part and the Archean buried-hill metamorphic granite in the lower part.A multi-layer reservoir structure of glutenite pore zone,weathering crust dissolution fracture zone and inner fracture zone is formed.These reservoirs are complex in genesis and diverse in type.Second,the Archean buried-hill metamorphic granite reservoir can be vertically divided into weathering crust,inner fracture zone and tight zone,and it presents the dual characteristics of porous and fractured media.Third,the buried-hill weathering crust is mainly affected by strong dissolution and leaching superimposed with fracturing,forming fractured-porous reservoir space.The reservoir of inner fracture zone is mainly controlled by the superimposition of three-phrase fractures,which forms the main development period of buried-hill fractures since the Yanshanian.Fourth,the glutenite of Kongdian Fm is a typical sieve deposit and it is mainly controlled by the late dissolution.Fifth,migmatization and supercritical fluid cryptoexplosion play a constructive role in the development of the reservoirs.In conclusion,the understanding of buried-hill glutenite and metamorphic reservoir system developed in this belt is conductive to determining the target and direction of next oil and gas exploration in this area.展开更多
The work functions of the （110） and （10（3） surfaces of LaB6 are determined from ambient pressure to 39.1 GPa. The work function of the （110） surface slowly decreases but that of the （100） surface remains at a...The work functions of the （110） and （10（3） surfaces of LaB6 are determined from ambient pressure to 39.1 GPa. The work function of the （110） surface slowly decreases but that of the （100） surface remains at a relatively constant value. To determine the reason for this difference, the electron density distribution （EDD） is determined from high-pressure single-crystal x-ray diffraction data by the maximum entropy method. The EDD results show that the chemical bond properties in LaB6 play a key role also investigated by single-crystal x-ray diffraction. In observed from ambient pressure to 39.1 GPa. The structural stability of LaB6 under high pressure is this study, no structural or electronic phase transition is展开更多
基金supported by the National Natural Science Foundation of China(22409065)the Guangdong Basic and Applied Basic Research Foundation(2022A1515011906)+2 种基金the China Postdoctoral Science Foundation(2023M731153)the Research Fund Program of Guangdong Provincial Key Laboratory of Fuel Cell Technologythe Postdoctoral Fellowship Program of CPSF(GZC20230868).
文摘The application of conventional manganese dioxide(MnO_(2))materials in sodium-ion supercapacitors(Na-SCs)is considerably limited by their low conductivity and structural instability.Biomimetic morphology engineering can optimize the electrochemical performance of MnO_(2).Here,based on the metal-organic frameworks(MOFs)-derived method and electrochemical reconstruction,a coral-like MnO_(2)structure integrated with a functional nitrogen-doped carbon(NC)coating is designed for Na-SC application.The bioinspired coral-like structure captures numerous electrolyte ions and increases the Na+concentration on the electrode surface,which is beneficial for optimizing the Na+transport pathway and accelerating the electrode reaction kinetics.Moreover,the coral-like crosslinked structure effectively enhances the mechanical properties,enabling the maintenance of the structure of MnO_(2)-based electrodes during long-term operation.Furthermore,in/ex-situ characterizations are performed to elucidate the mechanism of lattice transformation during electrochemical phase reconstruction.Additionally,the theoretical calculation and simulation results reveal the ion/electron dynamics in the fabricated electrode.The prepared electrode demonstrates excellent capacitance storage ability(340.7 F g^(−1)at 0.5 A g^(−1))and cycling stability(85.1%capacitance retention after 10,000 cycles).The assembled hybrid device exhibits exceptional life-span(82.0%capacitance retention after 10,000 cycles)and exceptional energy density(36.5 Wh kg^(−1)).This study provides a reliable biomimetic morphology design strategy for MnO_(2)cathodes,paving the way for the fabrication of high-performance Na-SCs.
基金supported by the Natural Science Foundation of Shandong Province(Nos.ZR2024QE450,ZR2024QB302 and ZR2024QB004)the Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202211249)Research Program of Qilu Institute of Technology(Nos.QIT 23TP019,QIT23TP010 and QIT24NN007)。
文摘The large volume expansion and rapid capacity attenuation of tin-based electrodes are the main factors limiting their commercial application.The reasonable design of electrode material structure is particularly important for improving its electrochemical performance.Herein,phosphorus-modified graphene encapsulated Sn_(6)O_(4)(OH)_(4)nanoparticles composite(P-Sn_(6)O_(4)(OH)_(4)@RGO)with crystalline-amorphous heterostructure has been successfully designed and prepared.The design of crystalline-amorphous structure has largely enhanced the active sites,and the construction of a graphene encapsulation structure has greatly alleviated volume expansion.Notably,P-Sn_(6)O_(4)(OH)_(4)@RGO obtained an excellent high-rate longterm cycling performance for lithium-ion batteries anode,reaching a high specific capacity of 970 m Ah/g at 1.0 A/g after 1450 cycles.This work demonstrates that restructuring the electrode material's structure and phase through phosphorus modification can effectively improve the electrochemical performance of tin-based electrode materials.
基金supported by the National Key Research and Development Project (Grant No. 2016 YFB 1101403)the National Key Foundation for Exploring Scientific Instrument of China (Grant No. 2016 YQ 51627805)
文摘Additively manufactured Ti-6 Al-4 V lattice structures have found important niche applications. However, they often show insufficient compressive ductility or insufficient structural integrity. In this study,a batch of 45 octahedral Ti-6 Al-4 V lattice structures was manufactured in three different strut diameters(0.5, 1.0, 1.5 mm) by selective electron beam melting(SEBM). The influence of post-SEBM annealing on the compressive deformation characteristics of the lattice structure was investigated. The as-built Ti-6 Al-4 V lattices fragmented when the compressive strain reached 13%–23% depending on strut diameter.Annealing at 950?C(β transus temperature: 995?C) only slightly improved the compressive ductility of the lattice structures. However, annealing at 1050?C(β-annealing) fundamentally changed the compressive deformation mode of the lattice structures. The resultant compressive stress-strain curve was featured by a long smooth plateau and no facture occurred even after significant densification of the lattice structure had taken place(>50% of compressive strain).
基金supported by the NSFC-JSPS joint research program(No.51961145202)the Natural Science Foundation of Heilongjiang Province,China(No.C2018035)。
文摘Pd modified electrodes possess problems such as easy agglomeration and low electrolytic ability,and the use of manganese dioxide(MnO_(2)) to facilitate Pd reduction of organic pollutants is just started.However,there is still a limited understanding of how to match the Pd load and MnO_(2) to realize optimal dechlorination efficiency at minimum cost.Here,a Pd/MnO_(2)/Ni foam cathode was successfully fabricated and applied for the efficient electrochemical dechlorination of 2,4,6-trichlorophenol(2,4,6-TCP).The optimal electrocatalytic hydrodechlorination(ECH)performance with 2,4,6-TCP dechlorination efficiency(92.58%in 180 min)was obtained when the concentration of PdCl_(2) precipitation was 1 mmol/L,the deposition time of MnO_(2) was 300 s and cathode potential was-0.8 V.Performance influenced by the exogenous factors(e.g.,initial pH and coexisted ions)were further investigated.It was found that the neutral pH was the most favorable for ECH and a reduction in dechlorination efficiency(6%~47.6%)was observed in presence of 5 mmol/L of NO_(2)^(-),NO_(3)^(-),S^(2-)or SO_(3)^(2-).Cyclic voltammetry(CV)and quenching experiments verified the existence of three hydrogen species on Pd surface,including adsorbed atomic hydrogen(H^(*)_(ads)),absorbed atomic hydrogen(H^(*)_(abs)),and molecular hydrogen(H_(2)).And the introduction of MnO_(2)promoted the generation of atomic H^(*).Only adsorbed atomic hydrogen(H^(*)_(ads)) was confirmed that it truly facilitated the ECH process.Besides H^(*)_(ads) induced reduction,the direct reduction by cathode electrons also participated in the 2,4,6-TCP dechlorination process.Pd/MnO_(2)/Ni foam cathode shows excellent dechlorination performance,fine stability and recyclable potential,which provides strategies for the effective degradation of persistent halogenated organic pollutants in groundwater.
基金This project is supported by National Defense Science and Technology Multi-vocation Foundation in Advance Research of China(No. 97J465JW0408).
文摘Some approaches to measure parallel 6-degree of freedom platform's posturestatically and to calibrate the platform's actual structural parameters by measuring a series of theplatform's varying postures are studied. In the case where high posture accuracy is requiredrelatively, to obtain the platform's actual structural parameters is very important. Threedimensions measurement with 2 theodolites are used to obtain the platform's postures statically andNewton iterative method is adopted to calibrate structural parameters. Some measures taken in themeasurement and the calibration are discussed in detail. And the experiment results of theplatform's posture control before and after the calibration are given. The results show that theplatform's posture control accuracy after the calibration is improved notably.
基金supported by grants from the National Natural Science Foundation of China(no.32100111,21934005)Guangdong Basic and Applied Basic Reuter Foundation(no.2019A1515110220)+1 种基金China Postdoctoral Science Foundation(no.2020M682900)Shenzhen High-level Hospital Construction Fund.
文摘Noroviruses(NoVs)are the primary cause of acute gastroenteritis worldwide.Histo-blood group antigens(HBGAs)are receptors or attachment factors that affect the prevalence and host susceptibility of NoVs.GII.6 NoV is one of the predominant genotypes in humans,which recognizes the type ABO secretor of HBGAs.However,the structural basis of GII.6 NoV's interaction with HBGAs receptors remains elusive.In this study,we investigated the binding features of the GII.6 strain to HBGAs using saliva-and glycan-ELISA assays and characterized the molecular basis of the GII.6 virus that recognizes H disaccharide.We showed that the GII.6 P domain recognized some A and O secretor's saliva samples,most B secretor's saliva samples,and H disaccharide antigen,but did not bind non-secretors’saliva.Further,we determined the crystal structures of GII.6 and its complex with H disaccharides at 1.7Å,revealing that the P domain of GII.6 shares the conventional binding interface and mode of GII HBGAs.Single residue mutations at the GII.6-H binding sites could inhibit the binding of GII.6 to HBGAs,demonstrating that the interaction residues were crucial in maintaining NoV-glycan integrity.Finally,structural and sequence analyses showed that the major residues of the GII.6-H interaction were conserved among NoVs in the GII genogroup.Taken together,our study characterized the functional and structural features of GII.6 that allow it to interact with HBGAs,and shed light on NoV evolution,epidemiology,and anti-viral drug development.
基金This work was supported by the National Natural Science Foundation of China (No. 20571057)
文摘A polynuclear complex [Cd（endc）（H20）]n·nH2O （endc = endo-norbornene-cis- 5,6-dicarboxylate anion） has been synthesized by the hydrothermal reaction of cadmium nitrate tetrahydrate with endo-norbornene-cis-5,6-dicarboxylic acid in 1：1 molar ratio, and structurally characterized by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/c with α = 1.16471（7）, b = 0.95334（7）, c = 0.91109（9） nm, Z= 4, V= 1.01035（14） nm^3, D, = 2.160 g/cm^3,μ = 2.172 mm^-1, F（000） = 648, R = 0.0302 and wR = 0.0752. According to structural analysis, each Cd（II） ion is coordinated to six O atoms from three endc anions and one water molecule, giving a distorted octahedral geometry. Two- dimensional layer arrangement of the title complex is constructed from the bridging nature of endc. It is worth notice that adjacent two-dimensional layers are joined together to form a three-dimensional supramolecular framework via intermolecular hydrogen bonding interactions.
基金financially supported by the National Natural Science Foundation of China(Nos.22105164 and 21875205)the National Natural Science Foundation of Hebei Province(No.B2022203009)+1 种基金Hebei Province Foundation for the National Natural Science Foundation(No.206Z4404G)the subsidy for Hebei Key Laboratory of Applied Chemistry after Operation Performance(No.22567616H)。
文摘Although pseudocapacitive manganese dioxide(MnO_(2))integrates the high-power merit of carbonaceous materials with the high-energy merit of battery-type materials,it still has a long way to go in achieving a more satisfactory balance of higher energy and power density,and in decoupling the relationship of structural characteristics with energy storage performance.To realize such goals,a bottom-up[WO_(6)]-perturbed[MnO_(6)]assembly strategy has been developed here due to their similar structure,yet mismatched lattice parameters.This facile protocol is capable of finely controlling the morphology and crystal structure of MnO_(2)by adjusting its internal[WO_(6)]concentration.Therefore,the as-prepared W_xMnO_(2)is treated as an ideal platform to scrutinize the correlations of the structure with the energy storage performance.The operando Raman spectra and finite element analysis have fully demonstrated the superiority of the locally ordered defects-enriched structure of W_(0.02)-MnO_(2),which could reach a favorable balance between the ion diffusion equilibrium time and the number of active sites.As a result,the W_(0.02)-MnO_(2)is able to deliver a high capacitance of 292 F·g^(-1)at a current density of 1 A·g^(-1)and a remarkable rate performance with a 60%capacity retention at a current density of 50 A·g^(-1).The further unveiled structure-performance relationship provides a guideline for the design of better pseudocapacitive energy storage devices.
文摘Structure model of charge-ordered La_0.33 Ca_0.67 MnO_3, perovskite is one of current focused study in condensed matter physics. There are great discrepancies in previous studies in this field. Our transmission electron microscopy study confirms Wigner crystal model with transverse displacement and is not consisent with the hi-stripe model with longitudinal displacement. We observed incommensurate modulation and anti-phase domains with a displacement vector a_co/3 in charge--ordered La_0.33 Ca_0.67 MnO_3, perovskite.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51572108,51632002,11504127,11674122,11574112,11474127,and11634004)the 111 Project,China(Grant No.B12011)+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT 15R23)the National Found for Fostering Talents of Basic Science,China(Grant No.J1103202)
文摘In situ Raman spectroscopy and x-ray diffraction measurements are used to explore the structural stability of CaB6 at high pressures and room temperature. The results show no evidence of structural phase transitions up to at least 40 GPa.The obtained equation of state with smooth pressure dependencies yields a zero-pressure isothermal bulk modulus B0=170(5) GPa, which agrees well with the previous measurements. The frequency shifts for A1g, Eg, and T2g vibrational modes of polycrystalline CaB6 are obtained with pressure uploading. As the pressure increases, all the vibration modes have smooth monotonic pressure dependence. The Gr¨uneisen parameter of Eg modes is the largest, indicating its largest dependence on the volume of a crystal lattice.
基金Project supported by the National Natural Science Foundation of China(Grant No.11574220)Fundamental Research Funds for the Central Universities,China(Grant No.SWU118055)+1 种基金the Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(the second phase)China
文摘The exploration of the appropriate red phosphor with good luminescence properties is an important issue in the development of current white light-emitting diode(WLED) devices. Transition metal Mn-doped compounds are fascinating luminescent materials. Herein, we performed a systematic theoretical study of the microstructure and optical properties of K_2TiF_6:Mn^(4+) using the CALYPSO structure search method in combination with first-principles calculations. We uncovered a novel structure of K_2TiF_6:Mn^(4+) with space group P-3m1 symmetry, where the impurity Mn_(4+) ions are accurately located at the center of the MnF_6 octahedra. Based on our developed complete energy matrix diagonalization(CEMD)method, we calculated transition lines for ~2E_g →~4A_2,~4A_2→~4T_2, and^4A_2→T2at 642 nm, 471 nm, and 352 nm,respectively, which are in good agreement with the available experimental data. More remarkably, we also found another transition(~4A_2→~2T_2) that lies at 380 nm, which should be a promising candidate for laser action.
基金supported by the National Major Science and Technology Project“Comprehensive Study on Buried-Hill Reservoir-Forming in the Bohai Sea and Favorable Exploration Direction”(No.:2016ZX05024-003-010)the Scientific Research Project of CNOOC“Petroleum Geological Characteristics,Forming Mechanism of Typical Oil&Gas Reservoir and Prediction of Prospects of the Buried Hill in the Bohai Sea Area”(No.:CCL2014TJXZSS0870).
文摘The BZ19-6 deep buried-hill structural belt in the southwest of Bozhong Sag,Bohai Bay Basin,is a newly discovered super-giant oil and gas bearing area.The study on its reservoirs is still in the early stage,and the characteristics and control factors of reservoir development are not understood deeply.In this paper,cores,sidewall cores,rock sections were analyzed and described.Then,based on regional structural setting,mud logging and logging data,the buried-hill reservoirs in this area were analyzed from the aspects of petrological characteristics,reservoir space types and physical properties,the inherent factors influencing the development of the reservoirs were discussed,and distribution laws of the reservoirs were investigated.And the following research results were obtained.First,the deep buried-hill reservoirs of this belt are a pan-buried hill reservoir system composed of the Palaeocene-Eocene Kongdian Fm glutenite in the upper part and the Archean buried-hill metamorphic granite in the lower part.A multi-layer reservoir structure of glutenite pore zone,weathering crust dissolution fracture zone and inner fracture zone is formed.These reservoirs are complex in genesis and diverse in type.Second,the Archean buried-hill metamorphic granite reservoir can be vertically divided into weathering crust,inner fracture zone and tight zone,and it presents the dual characteristics of porous and fractured media.Third,the buried-hill weathering crust is mainly affected by strong dissolution and leaching superimposed with fracturing,forming fractured-porous reservoir space.The reservoir of inner fracture zone is mainly controlled by the superimposition of three-phrase fractures,which forms the main development period of buried-hill fractures since the Yanshanian.Fourth,the glutenite of Kongdian Fm is a typical sieve deposit and it is mainly controlled by the late dissolution.Fifth,migmatization and supercritical fluid cryptoexplosion play a constructive role in the development of the reservoirs.In conclusion,the understanding of buried-hill glutenite and metamorphic reservoir system developed in this belt is conductive to determining the target and direction of next oil and gas exploration in this area.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11274030 and 11474281
文摘The work functions of the （110） and （10（3） surfaces of LaB6 are determined from ambient pressure to 39.1 GPa. The work function of the （110） surface slowly decreases but that of the （100） surface remains at a relatively constant value. To determine the reason for this difference, the electron density distribution （EDD） is determined from high-pressure single-crystal x-ray diffraction data by the maximum entropy method. The EDD results show that the chemical bond properties in LaB6 play a key role also investigated by single-crystal x-ray diffraction. In observed from ambient pressure to 39.1 GPa. The structural stability of LaB6 under high pressure is this study, no structural or electronic phase transition is
