Plant-based fermentations provide an untapped source for novel biotechnological applications.In this study,a probiotic named Lactobacillus fermentum 21828 was introduced to ferment Lentinus edodes.Polysaccharides were...Plant-based fermentations provide an untapped source for novel biotechnological applications.In this study,a probiotic named Lactobacillus fermentum 21828 was introduced to ferment Lentinus edodes.Polysaccharides were extracted from fermented and non-fermented L.edodes and purified via DEAE-52 and Sephadex G-100.The components designated F-LEP-2a and NF-LEP-2a were analyzed by FT-IR,HPGPC,HPAEC,SEM,GC-MS and NMR.The results revealed that probiotic fermentation increased the molecular weight from 1.16×10^(4) Da to 1.87×10^(4) Da and altered the proportions of glucose,galactose and mannose,in which glucose increased from 45.94%to 48.16%.Methylation analysis and NMR spectra indicated that F-LEP-2a and NF-LEP-2a had similar linkage patterns.Furthermore,their immunomodulatory activities were evaluated with immunosuppressive mice.NF-LEP and F-LEP improved immune organ indices,immunoglobulin(Ig G and Ig M)and cytokines concentrations;restored the antioxidation capacity of liver;and maintained the balance of gut microbiota.F-LEP displayed better moderating effects on the spleen index,immunoglobulin,cytokines and the diversity of gut microbiota than NF-LEP(200,400 mg/kg).Our study provides an efficient and environment-friendly way for the structural modification of polysaccharides,which helps to enhance their biological activity and promote their wide application in food,medicine and other fields.展开更多
The layout and characteristics of the hard X-ray spectroscopy beamline(BL11B)at the Shanghai synchrotron radiation facility are described herein.BL11B is a bending-magnet beamline dedicated to conventional and millise...The layout and characteristics of the hard X-ray spectroscopy beamline(BL11B)at the Shanghai synchrotron radiation facility are described herein.BL11B is a bending-magnet beamline dedicated to conventional and millisecond-scale quick-scanning X-ray absorption fine structures.It is equipped with a cylindrical collimating mirror,a double-crystal monochromator comprising Si(111)and Si(311),a channel-cut quick-scanning Si(111)monochromator,a toroidal focusing mirror,and a high harmonics rejection mirror.It can provide 5-30 keV of X-rays with a photon flux of~5×10^(11)photons/s and an energy resolution of~1.31×10^(-4)at 10 keV.The performance of the beamline can satisfy the demands of users in the fields of catalysis,materials,and environmental science.This paper presents an overview of the beamline design and a detailed description of its performance and capabilities.展开更多
Solid-state batteries are rising rapidly in response to the fast-increasing energy demand.Metal-organic framework(MOF) loaded with ionic liquids has brought new opportunities for solid-state batteries owing to its goo...Solid-state batteries are rising rapidly in response to the fast-increasing energy demand.Metal-organic framework(MOF) loaded with ionic liquids has brought new opportunities for solid-state batteries owing to its good interfacial compatibility and high ionic conductivity. MOF-808 is selected to be filled with Li-contained ionic liquid for structure and ion dynamics investigation using nuclear magnetic resonance(NMR) and X-ray diffraction.This study finds that the introduced ionic liquid would partially soften the matrix of MOF-808 and thus yield amorphous phase. By selective isotope replacement under cycling symmetric ^(6)Li metal cell, Li^(+)ion is observed to mainly go cross ionic liquid in the open channel of matrix under potential polarization.展开更多
Zr-based amorphous alloys have attracted extensive attention because of their large glassy formation ability, wide supercooled liquid region, high elasticity, and unique mechanical strength induced by their icosahedra...Zr-based amorphous alloys have attracted extensive attention because of their large glassy formation ability, wide supercooled liquid region, high elasticity, and unique mechanical strength induced by their icosahedral local structures.To determine the microstructures of Zr–Cu clusters, the stable and metastable geometry of Zr_(n)Cu(n=2–12) clusters are screened out via the CALYPSO method using machine-learning potentials, and then the electronic structures are investigated using density functional theory. The results show that the Zr_(n)Cu(n ≥ 3) clusters possess three-dimensional geometries, Zr_(n)Cu(n≥9) possess cage-like geometries, and the Zr_(12)Cu cluster has icosahedral geometry. The binding energy per atom gradually gets enlarged with the increase in the size of the clusters, and Zr_(n)Cu(n=5,7,9,12) have relatively better stability than their neighbors. The magnetic moment of most Zr_(n)Cu clusters is just 1μB, and the main components of the highest occupied molecular orbitals(HOMOs) in the Zr_(12)Cu cluster come from the Zr-d state. There are hardly any localized two-center bonds, and there are about 20 σ-type delocalized three-center bonds.展开更多
Acute pancreatitis(AP)is a common acute abdomen disease of the digestive system.It has a potentially fatal risk because of its variable severity and various complications.With the widespread application of the Revised...Acute pancreatitis(AP)is a common acute abdomen disease of the digestive system.It has a potentially fatal risk because of its variable severity and various complications.With the widespread application of the Revised Atlanta Classification,new requirements for AP imaging reports are introduced.Experts in abdominal radiology and pancreatology in the United States published the first structured computed tomography reporting template for AP in 2020.However,there is no corresponding structured magnetic resonance imaging(MRI)reporting template globally.Therefore,this article focuses on the structured MRI report of AP images from our pancreatitis imaging center,which is intended to improve the systematic understanding of this disease and standardize the writing of MRI structured reports.In the meantime,we aim to promote the clinical diagnosis and assessment of MRI efficacy for AP and its multiple complications.It is further intended to facilitate academic exchanges and scientific research between different medical centers.展开更多
The competition between different magnetic structures in hole-doped Fe-pnicitides is explored based on an extended five-orbital Hubbard model including long-range Coulomb interactions.Our results show that the stabili...The competition between different magnetic structures in hole-doped Fe-pnicitides is explored based on an extended five-orbital Hubbard model including long-range Coulomb interactions.Our results show that the stabilized magnetic structure evolves with increasing hole doping level.Namely,the stripe antiferromagnetic phase dominates at zero doping,while magnetic structures with more antiferromagnetic linking numbers such as the staggered tetramer,staggered trimer,and staggered dimer phases become energetically favorable as the hole density increases.At a certain doping level,energy degeneracy of different magnetic structures appears,indicating strong magnetic frustration and magnetic fluctuations in the system.We suggest that the magnetic competition induced by the hole doping may explain the fast decrease of the Neel temperature TNand the moderately suppressed magnetic moment in the hole doped Fe-pnicitides.Moreover,our results show a sign reversal of the kinetic energy anisotropy as the magnetic ground state evolves,which may be the mechanism behind the puzzling sign reversal of the in-plane resistivity anisotropy in hole-doped Fe-pnicitides.展开更多
In order to reduce the external magnetic field and improve the conversion efficiency of high-power microwave generation devices with low external magnetic field,a novel diode with an embedded soft magnetic and shieldi...In order to reduce the external magnetic field and improve the conversion efficiency of high-power microwave generation devices with low external magnetic field,a novel diode with an embedded soft magnetic and shielding structure is proposed.The soft magnetic material is designed to enhance the local magnetic field in the diode region.Moreover,the diode applies a shielding structure which can reduce the radial electric field.From simulation research,it is found that the emission and transmission quality of the electron beam with low magnetic field is greatly improved when loading this diode.Through simulation research,it is verified that the diode can increase the conversion efficiency of the transit-time oscillator(TTO)from 30%to 36.7%.In our experimental study,under the conditions of a diode voltage of 540 kV and a current of 10.5 kA,the output microwave power is 1.51 GW when loading the novel diode and the microwave frequency is 4.27 GHz when an external guiding magnetic field of 0.3 T is applied.The corresponding conversion efficiency is improved from 20.0%to 26.6%,which is 6.6%higher than that of a device loaded with a conventional diode.Our experiments have verified that this novel diode can effectively improve the conversion efficiency of high-power microwave sources operating with low magnetic field,and contribute to the miniaturization and compactness of high-power microwave devices.展开更多
The impact of resonant magnetic perturbation(RMP)on blob motion and structure in the SOL of the HL-2A tokamak is studied using a gas puff imaging diagnostic.Ellipse fitting is applied to study the structure and motion...The impact of resonant magnetic perturbation(RMP)on blob motion and structure in the SOL of the HL-2A tokamak is studied using a gas puff imaging diagnostic.Ellipse fitting is applied to study the structure and motion of blobs quantitatively.The radial locations,amplitudes and scale sizes of blobs are obtained based on the fitted ellipse.Furthermore,based on the measurement of blob location,the radial and poloidal velocities of blobs are calculated.With the application of RMP,the edge poloidal shear flow is significantly weakened and the wave number spectrum changes from quasisymmetric to significantly up-down asymmetric.The application of RMP also causes the detected blob location to be much further into the far scrape-off layer(SOL)and increases the blob amplitude.Blob poloidal velocity in the SOL is slowed.Larger-size and longer-lifetime blobs are observed with RMP.With the application of RMP,stronger-amplitude and larger-size blobs are detected in the far SOL and they may cause a more serious erosion problem to the first wall.展开更多
The main scope of this research is to detect geologic structure trends affecting the study area, determine uranium anomalous areas and define alteration zones. Airborne magnetic data were used to detect the geologic s...The main scope of this research is to detect geologic structure trends affecting the study area, determine uranium anomalous areas and define alteration zones. Airborne magnetic data were used to detect the geologic structure trends affecting the study area through applying edge detectors such as total horizontal derivative, analytic signal and tilt derivative. The radio-spectrometry data and Landsat image data were used in determining the uranium anomalous areas and alteration zones. The integration between geology, magnetic and Landsat image was applied through constructing lineaments density map for the three data sets resulting in the leading of NW-SE trend all over the area. This integration makes clear that the basement (Red Sea hills), Esh El-mallaha range and G. Zeit are limiting two large basins (West Mallaha and Zeit). In addition, the main areas of uranium enrichment (Duwi formation at Esh El-Mallaha range) are found to be well related to alteration zones.展开更多
The electronic structures and magnetism of Fe nanowires along the [110] direction on Cu(001) and Ag(001) [Fe(nw)/Cu(001) and Fe(nw)/Ag(001)] are investigated by using the all-electron full-potential linear...The electronic structures and magnetism of Fe nanowires along the [110] direction on Cu(001) and Ag(001) [Fe(nw)/Cu(001) and Fe(nw)/Ag(001)] are investigated by using the all-electron full-potential linearized augmented plane wave method in the generalized gradient approximation. It is found that the magnetic moment of Fe atom for the Fe(nw)/Cu(001) is 2.99#B, which is slightly smaller than that (3.02μB) for the Fe(nw)/Ag(001) but much larger than that (2.22μB) for the bcc iron. The great enhancement of magnetic moment in the Fe nanowires can be explained by the Fe d-band narrowing and enhancement of the spin-splitting due to a reduction in coordination number, From the calculated spin-polarized layer-projected density of states, it is found that the Fe 3d-states are strongly hybridized with the adjacent Cu 3d-states in the Fe(nw)/Cu(001), and there exists a strong hybridization between the Fe sp-and the adjacent Ag 4d-states in the Fe(nw)/Ag(001).展开更多
Two single and double chain manganese coordination polymers {[Mn(L1)(H_2O)_2]NO_3}_n(1) and [Mn(L2)_2(H_2O)]_n(2)(HL1 = 2,2?:6?,2??-terpyridine-4?-carboxylic acid, HL2 = 4?-(4-carboxyphenyl)-2,2?:6?,2??-terpyridine) h...Two single and double chain manganese coordination polymers {[Mn(L1)(H_2O)_2]NO_3}_n(1) and [Mn(L2)_2(H_2O)]_n(2)(HL1 = 2,2?:6?,2??-terpyridine-4?-carboxylic acid, HL2 = 4?-(4-carboxyphenyl)-2,2?:6?,2??-terpyridine) have been synthesized hydrothermally, and characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. Compound 1 crystallizes in monoclinic space group P2/c, while 2 crystallizes in triclinic, space group P1. Crystal data for 1: C_(16)H_(14)MnN_4O_7, Mr = 429.25, a = 10.684(2), b = 9.338(1), c = 9.896(2) ?, β = 113.89(3)o, V = 902.7(3) ?~3, Z = 2, T = 153(2) K, Dc = 1.579 g/cm^3, μ = 0.780 mm-1, F(000) = 438, R = 0.1084, wR = 0.3507, and GOF = 1.069; For 2: C44 H30 MnN6 O5, Mr = 777.68, a = 11.255(2), b = 11.554(2), c = 15.417(3) ?, α = 107.28(3), β = 101.07(3), γ = 107.23(3)o, V = 1740.2(6) ?~3, Z = 2, T = 293(2) K, Dc = 1.484 g/cm3, μ = 0.440 mm^(-1), F(000) = 802, R = 0.0471, wR = 0.1050, and GOF = 0.948. In both compounds, the central Mn(Ⅱ) ions adopt the same distorted pentagonal-bipyramid geometry [MnN_3O_4] with different secondary structure units. L1 ligand adopts the μ_2-1κ~3N,N?,N??:2κ~2O,O? mode to coordinate with mononuclear manganese to build a single chainlike compound 1, while L2 employs μ_3-1κ~3N,N?,N??:2κ~2O,O?:3κ~1O and 1κ~1O modes to link dimeric Mn_2O_2 to exhibit a double chainlike 2. Both compounds display weak antiferromagnetic coupling interactions.展开更多
The ground-state configurations of the Nbn (n = 2-11) clusters are studied through the first-principles calculations. It is found that niobium clusters (n = 2-11) tend to form compact structures with low symmetry....The ground-state configurations of the Nbn (n = 2-11) clusters are studied through the first-principles calculations. It is found that niobium clusters (n = 2-11) tend to form compact structures with low symmetry. The clusters with 4, 8 and 10 atoms axe found to be magic and have relatively large highest occupied-lowest unoccupied molecular orbital (HOMO-LUMO) gaps. The Nbn clusters possess low magnetic moments, which exhibit an odd-even oscillational character. The analyses of calculated electronic density and population of the lowest-energy niobium clusters for n =2, 3, 5, 7, 9, 11 show that the total magnetic moments of Nbn originate mainly from a few Nb atoms with longer spacings between them in most cases, while they are located on two Nb atoms for n = 2, 3, 5. The total magnetic moments come mainly from the 4d local moments but with the exception of the Nb5 cluster.展开更多
A dinuclear dysprosium(III) compound,[Dy2(μ2-OH)2(QLC)4(1,10-phen)2]·4H2O(1)(QLC-= 2-quinolinecarboxylate and 1,10-phen = 1,10-phenanthroline),was synthesized and structurally and magnetically charac...A dinuclear dysprosium(III) compound,[Dy2(μ2-OH)2(QLC)4(1,10-phen)2]·4H2O(1)(QLC-= 2-quinolinecarboxylate and 1,10-phen = 1,10-phenanthroline),was synthesized and structurally and magnetically characterized.Compound 1 crystallizes in triclinic system,space group P1 with a = 10.9439(3),b = 11.2823(3),c = 12.2323(4) ?,α = 107.446(3),β = 91.700(3),γ = 91.511(2)°,V = 1439.25(8) A3,Z = 1,C(64)H(50)N8O(14)Dy2,Mr = 1480.12,Dc = 1.708 g/cm3,μ = 2.653 mm-1 and F(000) = 734.The final R = 0.0366 and w R = 0.0736 for 5816 observed reflections with I 〉 2σ(I).Compound 1 contains the mononuclear [Dy(QLC)2(1,10-phen)] subunit formed from one 1,10-phen and two QLC-ligands chelating Dy(III) ion.Two mononuclear [Dy(QLC)2(1,10-phen)] subunits are bridged by a pair of μ2-OH groups to give a centrosymmetric dinuclear [Dy2(μ2-OH)2(QLC)4(1,10-phen)2] with each Dy(III) ion being eight-coordinated.Detailed susceptibility measurements revealed that compound 1 does not show slow magnetic relaxation under zero direct-current field but exhibits field-induced slow magnetic relaxation under 2 kOe applied field.展开更多
Electronic and magnetic properties of Fe1-xCoxSi alloys were investigated by using a full-potential linear augmented-plane-wave method based on density functional theory. Electronic structure calculation demonstrates ...Electronic and magnetic properties of Fe1-xCoxSi alloys were investigated by using a full-potential linear augmented-plane-wave method based on density functional theory. Electronic structure calculation demonstrates that half-metallic property appears in the Fe-rich region of 0 〈 x ≤ 0.25, while the alloys turn out to be a magnetic metal for x 〉 0.25. The concentration dependence of the magnetic moment of the alloys can be understood by the fixed Fermi level at minority band in Fe-rich region, as well as at the majority band in Co-rich region. In Fe-rich alloys, the electronic structure and the magnetic properties at Fe site depend mainly on the spin-polarization of nearest neighbouring Co atoms, while in Co-rich alloys, these features at Co site arise mainly from the neighbours of Fe atoms.展开更多
The electronic structure and magnetism of eskolaite are studied by using first-principles calculations where the on-site Coulomb interaction and the exchange interaction are taken into account and the LSDA+U method i...The electronic structure and magnetism of eskolaite are studied by using first-principles calculations where the on-site Coulomb interaction and the exchange interaction are taken into account and the LSDA+U method is used. The calculated energies of magnetic configurations are very well fitted by the Heisenberg Hamiltonian with interactions in five neighbour shells; interaction with two nearest neighbours is found to be dominant. The Neel temperature is calculated in the spin-3/2 pair-cluster approximation. It is found that the measurements are in good agreement with the calculations of lattice parameters, density of states, band gap, local magnetic moment, and the Neel temperature for the values of U and J that are close to those obtained within the constrained occupation method. The band gap is of the Mott-Hubbard type.展开更多
Ternary yttrium chromium sulfide,Y2CrS4,prepared by the solid-state reaction of Y2S3,Cr,and S,was found to exhibit an antiferromagnetic transition at about 64 K.The X-ray diffraction pattern at 300 K was refined with ...Ternary yttrium chromium sulfide,Y2CrS4,prepared by the solid-state reaction of Y2S3,Cr,and S,was found to exhibit an antiferromagnetic transition at about 64 K.The X-ray diffraction pattern at 300 K was refined with space group Pca2 1,and the structure parameters were determined to be a = 12.51 Ab = 7.53A,and c = 12.49A,We investigated the magnetotransport properties,and observed negative colossal magnetoresistance reaching up to 2.5 × 10^ 4 % in the semiconducting compound of Y2CrS4.展开更多
The self-assembly reactions of M^ⅡCl2 (M = Ni, Co) with the flexible bix ligand [bix = 1,4-bis(imidazole-1-ylmethyl)benzene] yielded a 2D network [N^Ⅲ(bix)2Cl2]n 1 and a 1D chain [Co^Ⅱ(bix)Cl2]n 2. Their cr...The self-assembly reactions of M^ⅡCl2 (M = Ni, Co) with the flexible bix ligand [bix = 1,4-bis(imidazole-1-ylmethyl)benzene] yielded a 2D network [N^Ⅲ(bix)2Cl2]n 1 and a 1D chain [Co^Ⅱ(bix)Cl2]n 2. Their crystal structures have been determined by X-ray single-crystal diffraction analysis. Complex 1 characters a two-dimensional grid-type structure and crystallizes in monoclinic, space group P21/c with a = 7.7231(7), b = 12.7787(9), c = 13.9374(13)A, β = 105.419(4)°, C28H28Cl2N8Ni, Mr = 606.19, Ζ = 2, V = 1326.0(2)A^3, Dc = 1.518 g/cm^3, μ = 0.969 mm^-1, F(000) = 628, R = 0.0429 and wR = 0.0783 for 2503 observed reflections (Ⅰ〉 2σ(Ⅰ)). Compound 2 is a one-dimensional chain and crystallizes in orthorhombic, space group Pbca with a = 11.3696(6), b = 10.2128(6), c = 14.4943(9) (A), C14H14Cl2CoN4, Mr = 368.12, Z = 4, V = 1683.01(17)A^3, Dc = 1.453 g/cm^3, μ = 1.334 mm^-1, F(000) = 748, R = 0.0317 and wR = 0.0800 for 1778 observed reflections (Ⅰ〉 2σ(Ⅰ)). Magnetic properties of the title complexes were also investigated.展开更多
Treatment of a heptadentate ligand 2,2'-(((pyridine-2,6-diyl-bis(methylene))- bis((pyridin-2-ylmethyl)azanediyl))bis(methylene))diphenol (H2L) possessing pyridinyl- and phenolate groups, with three eq...Treatment of a heptadentate ligand 2,2'-(((pyridine-2,6-diyl-bis(methylene))- bis((pyridin-2-ylmethyl)azanediyl))bis(methylene))diphenol (H2L) possessing pyridinyl- and phenolate groups, with three equivalents of Cu(C104)2·6H2O in methanol under base conditions, gave rise to a hexanuclear cluster complex [Cu6L2(OH)4](C104)4·4MeCN·0.5MeOH (1). Complex 1 crystallizes in triclinic, space group Pi with a = 12.068(12), b = 12.567(12), c = 16.279(16) A, α = 105.694(12), β = 93.631(13), γ = 112.017(11)°, V= 2166(4) A3, Z = 1,μ= 1.651 mm^-1, Dc = 1.599 Mg/m^3, T = 296(2) K, C74.5H795N14O24.5Cl4Cu6, Mr = 2086.12, F(000) = 1062.5, S = 1.061, R = 0.0521 and wR = 0.1270. In the cation of complex 1, the six copper cores are arranged into a two-parallel three-site strings configuration with each metal exhibits a slightly distorted square-pyramidal geometry, resulting from the connection of donor pyridinyi nitrogen and phenolate oxygen atoms in ligand H2L, and/or the oxygen donors in hydroxyl groups. In addition, magnetic susceptibility measurements revealed complex 1 displayed antiferromagnetic coupling.展开更多
Two 4,5-dichlorophthalate-based metal complexes, {[Cu(bipy)(dcpa)].H2O}n, (1) and {[Cu2Coipy)2(Hdcpa)3]·H2O·C2H5OH.Hdcpa} (2, H2dcpa = 4,5-dichlorophthalic acid and bipy = 2,2'-bipyridine), were ...Two 4,5-dichlorophthalate-based metal complexes, {[Cu(bipy)(dcpa)].H2O}n, (1) and {[Cu2Coipy)2(Hdcpa)3]·H2O·C2H5OH.Hdcpa} (2, H2dcpa = 4,5-dichlorophthalic acid and bipy = 2,2'-bipyridine), were synthesized and characterized structurally and magnetically. Complex 1 is of orthorhombic system, space group Fdd2 with a = 20.5821(8), b = 20.9013(12), c = 17.0270(7) A, V= 7324.9(6) A3, Dc = 1.707 g/cm3, Mr = 470.74, Z = 16, F(000) = 3792, p = 1.519 mm^-1, the final R = 0.0223 and wR = 0.0549 for 9239 observed reflections with I〉 2σ(I). Complex 2 crystallizes in triclinic, space group P1 with a = 14.1439(12), b = 14.2981(12), c = 15.1054(14) A, a = 72.121(2), β = 77.703(2),γ = 81.829(2)°, V= 2830.9(4) A3, Dc = 1.689 g/cm3, M,. = 1439.55, Z = 2, F(000) = 1452,μ = 1.207 mm^-1, the final R = 0.0536 and wR = 0.0981 for 16422 observed reflections with 1 〉 2σ(I). Complex 1 exhibits a diamond-like framework with centrosymmetric binuclear subunits extended by pairs of doubly deprotonated dcpa2- linkers. By contrast, 2 is an asymmetric binuclear entity bridged by carboxylate group of mono deprotonated Hdcpa- ligands. Weak anti- and ferromagnetic interactions are respectively mediated in the carboxylate aggregated binuclear subunits of 1 and 2.展开更多
Abstract: a novel tlhree dimenslonal network complex polymer,namely, GdF6 (CN)6. 4H2O; has been synthesized from water solntion of gadollinium chloride and potassium ferricyanide, The complex erystalized in the mon...Abstract: a novel tlhree dimenslonal network complex polymer,namely, GdF6 (CN)6. 4H2O; has been synthesized from water solntion of gadollinium chloride and potassium ferricyanide, The complex erystalized in the monoclinie system, space group c2; with a=12. 759 (6) b=7. 404 (1). c=13. 564 (5) A,z=4. β=90. 22 (3), Mr=441. 33,De=2. 28g/cm2, μ(Mo Kcr)=38. 36cm-1, F (000)=832, R=0. 065 for 1048 independent observed reflections. The coordinated of Fe (111) ion and Gd (111) ion are distorted octahedron and 4-capped trigonal prism, respectively. The varible- temperature magnetlc suscepttbility of the complex was measured over 4.2-300K, giving the exchange intergral 2J=-138.2cm-1,and indlcation that a mediate antiferromagnetic spinsxchange interaction between the Fe (111) ions and the Gd (111) lons within oach binuclear unit.展开更多
基金supported by grants from the National Key R&D Program of China(2019YFC1606701)。
文摘Plant-based fermentations provide an untapped source for novel biotechnological applications.In this study,a probiotic named Lactobacillus fermentum 21828 was introduced to ferment Lentinus edodes.Polysaccharides were extracted from fermented and non-fermented L.edodes and purified via DEAE-52 and Sephadex G-100.The components designated F-LEP-2a and NF-LEP-2a were analyzed by FT-IR,HPGPC,HPAEC,SEM,GC-MS and NMR.The results revealed that probiotic fermentation increased the molecular weight from 1.16×10^(4) Da to 1.87×10^(4) Da and altered the proportions of glucose,galactose and mannose,in which glucose increased from 45.94%to 48.16%.Methylation analysis and NMR spectra indicated that F-LEP-2a and NF-LEP-2a had similar linkage patterns.Furthermore,their immunomodulatory activities were evaluated with immunosuppressive mice.NF-LEP and F-LEP improved immune organ indices,immunoglobulin(Ig G and Ig M)and cytokines concentrations;restored the antioxidation capacity of liver;and maintained the balance of gut microbiota.F-LEP displayed better moderating effects on the spleen index,immunoglobulin,cytokines and the diversity of gut microbiota than NF-LEP(200,400 mg/kg).Our study provides an efficient and environment-friendly way for the structural modification of polysaccharides,which helps to enhance their biological activity and promote their wide application in food,medicine and other fields.
文摘The layout and characteristics of the hard X-ray spectroscopy beamline(BL11B)at the Shanghai synchrotron radiation facility are described herein.BL11B is a bending-magnet beamline dedicated to conventional and millisecond-scale quick-scanning X-ray absorption fine structures.It is equipped with a cylindrical collimating mirror,a double-crystal monochromator comprising Si(111)and Si(311),a channel-cut quick-scanning Si(111)monochromator,a toroidal focusing mirror,and a high harmonics rejection mirror.It can provide 5-30 keV of X-rays with a photon flux of~5×10^(11)photons/s and an energy resolution of~1.31×10^(-4)at 10 keV.The performance of the beamline can satisfy the demands of users in the fields of catalysis,materials,and environmental science.This paper presents an overview of the beamline design and a detailed description of its performance and capabilities.
基金supported by the National Natural Science Foundation of China(No.21974007).
文摘Solid-state batteries are rising rapidly in response to the fast-increasing energy demand.Metal-organic framework(MOF) loaded with ionic liquids has brought new opportunities for solid-state batteries owing to its good interfacial compatibility and high ionic conductivity. MOF-808 is selected to be filled with Li-contained ionic liquid for structure and ion dynamics investigation using nuclear magnetic resonance(NMR) and X-ray diffraction.This study finds that the introduced ionic liquid would partially soften the matrix of MOF-808 and thus yield amorphous phase. By selective isotope replacement under cycling symmetric ^(6)Li metal cell, Li^(+)ion is observed to mainly go cross ionic liquid in the open channel of matrix under potential polarization.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11864040,11964037,and 11664038)。
文摘Zr-based amorphous alloys have attracted extensive attention because of their large glassy formation ability, wide supercooled liquid region, high elasticity, and unique mechanical strength induced by their icosahedral local structures.To determine the microstructures of Zr–Cu clusters, the stable and metastable geometry of Zr_(n)Cu(n=2–12) clusters are screened out via the CALYPSO method using machine-learning potentials, and then the electronic structures are investigated using density functional theory. The results show that the Zr_(n)Cu(n ≥ 3) clusters possess three-dimensional geometries, Zr_(n)Cu(n≥9) possess cage-like geometries, and the Zr_(12)Cu cluster has icosahedral geometry. The binding energy per atom gradually gets enlarged with the increase in the size of the clusters, and Zr_(n)Cu(n=5,7,9,12) have relatively better stability than their neighbors. The magnetic moment of most Zr_(n)Cu clusters is just 1μB, and the main components of the highest occupied molecular orbitals(HOMOs) in the Zr_(12)Cu cluster come from the Zr-d state. There are hardly any localized two-center bonds, and there are about 20 σ-type delocalized three-center bonds.
文摘Acute pancreatitis(AP)is a common acute abdomen disease of the digestive system.It has a potentially fatal risk because of its variable severity and various complications.With the widespread application of the Revised Atlanta Classification,new requirements for AP imaging reports are introduced.Experts in abdominal radiology and pancreatology in the United States published the first structured computed tomography reporting template for AP in 2020.However,there is no corresponding structured magnetic resonance imaging(MRI)reporting template globally.Therefore,this article focuses on the structured MRI report of AP images from our pancreatitis imaging center,which is intended to improve the systematic understanding of this disease and standardize the writing of MRI structured reports.In the meantime,we aim to promote the clinical diagnosis and assessment of MRI efficacy for AP and its multiple complications.It is further intended to facilitate academic exchanges and scientific research between different medical centers.
基金the Guangxi Natural Science Foundation,China(Grant Nos.2022GXNSFAA035560and GuikeAD20159009)the Scientific Research Foundation of Guilin University of Technology(Grant No.GLUTQD2017009)。
文摘The competition between different magnetic structures in hole-doped Fe-pnicitides is explored based on an extended five-orbital Hubbard model including long-range Coulomb interactions.Our results show that the stabilized magnetic structure evolves with increasing hole doping level.Namely,the stripe antiferromagnetic phase dominates at zero doping,while magnetic structures with more antiferromagnetic linking numbers such as the staggered tetramer,staggered trimer,and staggered dimer phases become energetically favorable as the hole density increases.At a certain doping level,energy degeneracy of different magnetic structures appears,indicating strong magnetic frustration and magnetic fluctuations in the system.We suggest that the magnetic competition induced by the hole doping may explain the fast decrease of the Neel temperature TNand the moderately suppressed magnetic moment in the hole doped Fe-pnicitides.Moreover,our results show a sign reversal of the kinetic energy anisotropy as the magnetic ground state evolves,which may be the mechanism behind the puzzling sign reversal of the in-plane resistivity anisotropy in hole-doped Fe-pnicitides.
基金Project supported by the National Natural Science Foundation of China (Grant No. 61701516)
文摘In order to reduce the external magnetic field and improve the conversion efficiency of high-power microwave generation devices with low external magnetic field,a novel diode with an embedded soft magnetic and shielding structure is proposed.The soft magnetic material is designed to enhance the local magnetic field in the diode region.Moreover,the diode applies a shielding structure which can reduce the radial electric field.From simulation research,it is found that the emission and transmission quality of the electron beam with low magnetic field is greatly improved when loading this diode.Through simulation research,it is verified that the diode can increase the conversion efficiency of the transit-time oscillator(TTO)from 30%to 36.7%.In our experimental study,under the conditions of a diode voltage of 540 kV and a current of 10.5 kA,the output microwave power is 1.51 GW when loading the novel diode and the microwave frequency is 4.27 GHz when an external guiding magnetic field of 0.3 T is applied.The corresponding conversion efficiency is improved from 20.0%to 26.6%,which is 6.6%higher than that of a device loaded with a conventional diode.Our experiments have verified that this novel diode can effectively improve the conversion efficiency of high-power microwave sources operating with low magnetic field,and contribute to the miniaturization and compactness of high-power microwave devices.
基金supported by the National Key Research and Development Program of China(Nos.2022YFE03100002,2022YFE03010004 and 2019YFE03060002)National Natural Science Foundation of China(Nos.U1867222,U1967206 and 51821005)the Sichuan Natural Science Foundation(Nos.2022NSFSC1791 and 2020JDTD0030).
文摘The impact of resonant magnetic perturbation(RMP)on blob motion and structure in the SOL of the HL-2A tokamak is studied using a gas puff imaging diagnostic.Ellipse fitting is applied to study the structure and motion of blobs quantitatively.The radial locations,amplitudes and scale sizes of blobs are obtained based on the fitted ellipse.Furthermore,based on the measurement of blob location,the radial and poloidal velocities of blobs are calculated.With the application of RMP,the edge poloidal shear flow is significantly weakened and the wave number spectrum changes from quasisymmetric to significantly up-down asymmetric.The application of RMP also causes the detected blob location to be much further into the far scrape-off layer(SOL)and increases the blob amplitude.Blob poloidal velocity in the SOL is slowed.Larger-size and longer-lifetime blobs are observed with RMP.With the application of RMP,stronger-amplitude and larger-size blobs are detected in the far SOL and they may cause a more serious erosion problem to the first wall.
文摘The main scope of this research is to detect geologic structure trends affecting the study area, determine uranium anomalous areas and define alteration zones. Airborne magnetic data were used to detect the geologic structure trends affecting the study area through applying edge detectors such as total horizontal derivative, analytic signal and tilt derivative. The radio-spectrometry data and Landsat image data were used in determining the uranium anomalous areas and alteration zones. The integration between geology, magnetic and Landsat image was applied through constructing lineaments density map for the three data sets resulting in the leading of NW-SE trend all over the area. This integration makes clear that the basement (Red Sea hills), Esh El-mallaha range and G. Zeit are limiting two large basins (West Mallaha and Zeit). In addition, the main areas of uranium enrichment (Duwi formation at Esh El-Mallaha range) are found to be well related to alteration zones.
文摘The electronic structures and magnetism of Fe nanowires along the [110] direction on Cu(001) and Ag(001) [Fe(nw)/Cu(001) and Fe(nw)/Ag(001)] are investigated by using the all-electron full-potential linearized augmented plane wave method in the generalized gradient approximation. It is found that the magnetic moment of Fe atom for the Fe(nw)/Cu(001) is 2.99#B, which is slightly smaller than that (3.02μB) for the Fe(nw)/Ag(001) but much larger than that (2.22μB) for the bcc iron. The great enhancement of magnetic moment in the Fe nanowires can be explained by the Fe d-band narrowing and enhancement of the spin-splitting due to a reduction in coordination number, From the calculated spin-polarized layer-projected density of states, it is found that the Fe 3d-states are strongly hybridized with the adjacent Cu 3d-states in the Fe(nw)/Cu(001), and there exists a strong hybridization between the Fe sp-and the adjacent Ag 4d-states in the Fe(nw)/Ag(001).
基金supported by the Scientific Research Fund of Hunan Provincial Education Department(15C0818,17C0948)the Opening Fund of Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research(Ministry of Education of China)Hunan Normal University(KLCBTCMR201808)
文摘Two single and double chain manganese coordination polymers {[Mn(L1)(H_2O)_2]NO_3}_n(1) and [Mn(L2)_2(H_2O)]_n(2)(HL1 = 2,2?:6?,2??-terpyridine-4?-carboxylic acid, HL2 = 4?-(4-carboxyphenyl)-2,2?:6?,2??-terpyridine) have been synthesized hydrothermally, and characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. Compound 1 crystallizes in monoclinic space group P2/c, while 2 crystallizes in triclinic, space group P1. Crystal data for 1: C_(16)H_(14)MnN_4O_7, Mr = 429.25, a = 10.684(2), b = 9.338(1), c = 9.896(2) ?, β = 113.89(3)o, V = 902.7(3) ?~3, Z = 2, T = 153(2) K, Dc = 1.579 g/cm^3, μ = 0.780 mm-1, F(000) = 438, R = 0.1084, wR = 0.3507, and GOF = 1.069; For 2: C44 H30 MnN6 O5, Mr = 777.68, a = 11.255(2), b = 11.554(2), c = 15.417(3) ?, α = 107.28(3), β = 101.07(3), γ = 107.23(3)o, V = 1740.2(6) ?~3, Z = 2, T = 293(2) K, Dc = 1.484 g/cm3, μ = 0.440 mm^(-1), F(000) = 802, R = 0.0471, wR = 0.1050, and GOF = 0.948. In both compounds, the central Mn(Ⅱ) ions adopt the same distorted pentagonal-bipyramid geometry [MnN_3O_4] with different secondary structure units. L1 ligand adopts the μ_2-1κ~3N,N?,N??:2κ~2O,O? mode to coordinate with mononuclear manganese to build a single chainlike compound 1, while L2 employs μ_3-1κ~3N,N?,N??:2κ~2O,O?:3κ~1O and 1κ~1O modes to link dimeric Mn_2O_2 to exhibit a double chainlike 2. Both compounds display weak antiferromagnetic coupling interactions.
基金Project supported by the Program for Science & Technology Innovation Talents in Universities of Henan Province, China (Grant No 2009HASTIT003)the Natural Science Foundation of Henan University, China (Grant Nos 07ZRZD005 and 07YBZR046)the Foundation of Science and Technology Department of Henan Province, China (Grant No 082300410010)
文摘The ground-state configurations of the Nbn (n = 2-11) clusters are studied through the first-principles calculations. It is found that niobium clusters (n = 2-11) tend to form compact structures with low symmetry. The clusters with 4, 8 and 10 atoms axe found to be magic and have relatively large highest occupied-lowest unoccupied molecular orbital (HOMO-LUMO) gaps. The Nbn clusters possess low magnetic moments, which exhibit an odd-even oscillational character. The analyses of calculated electronic density and population of the lowest-energy niobium clusters for n =2, 3, 5, 7, 9, 11 show that the total magnetic moments of Nbn originate mainly from a few Nb atoms with longer spacings between them in most cases, while they are located on two Nb atoms for n = 2, 3, 5. The total magnetic moments come mainly from the 4d local moments but with the exception of the Nb5 cluster.
基金Supported by the National Natural Science Foundation of China(No.21561015)
文摘A dinuclear dysprosium(III) compound,[Dy2(μ2-OH)2(QLC)4(1,10-phen)2]·4H2O(1)(QLC-= 2-quinolinecarboxylate and 1,10-phen = 1,10-phenanthroline),was synthesized and structurally and magnetically characterized.Compound 1 crystallizes in triclinic system,space group P1 with a = 10.9439(3),b = 11.2823(3),c = 12.2323(4) ?,α = 107.446(3),β = 91.700(3),γ = 91.511(2)°,V = 1439.25(8) A3,Z = 1,C(64)H(50)N8O(14)Dy2,Mr = 1480.12,Dc = 1.708 g/cm3,μ = 2.653 mm-1 and F(000) = 734.The final R = 0.0366 and w R = 0.0736 for 5816 observed reflections with I 〉 2σ(I).Compound 1 contains the mononuclear [Dy(QLC)2(1,10-phen)] subunit formed from one 1,10-phen and two QLC-ligands chelating Dy(III) ion.Two mononuclear [Dy(QLC)2(1,10-phen)] subunits are bridged by a pair of μ2-OH groups to give a centrosymmetric dinuclear [Dy2(μ2-OH)2(QLC)4(1,10-phen)2] with each Dy(III) ion being eight-coordinated.Detailed susceptibility measurements revealed that compound 1 does not show slow magnetic relaxation under zero direct-current field but exhibits field-induced slow magnetic relaxation under 2 kOe applied field.
基金Project supported by the State Key Development Program for Basic Research of China (Grant No 2001CB610605), and the National Natural Science Foundation of China (Grant No 10474132).
文摘Electronic and magnetic properties of Fe1-xCoxSi alloys were investigated by using a full-potential linear augmented-plane-wave method based on density functional theory. Electronic structure calculation demonstrates that half-metallic property appears in the Fe-rich region of 0 〈 x ≤ 0.25, while the alloys turn out to be a magnetic metal for x 〉 0.25. The concentration dependence of the magnetic moment of the alloys can be understood by the fixed Fermi level at minority band in Fe-rich region, as well as at the majority band in Co-rich region. In Fe-rich alloys, the electronic structure and the magnetic properties at Fe site depend mainly on the spin-polarization of nearest neighbouring Co atoms, while in Co-rich alloys, these features at Co site arise mainly from the neighbours of Fe atoms.
基金Project supported by the Qianjiang Talent Project of Zhejiang Province, China (Grant No 2007R10028)the National Natural Science Foundation of China (Grant No 50802089)+2 种基金the Opening Project of State Key Laboratory of High Performance Ceramicsand Superfine Microstructure, China (Grant No SKL200805SIC)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of China (Grant No [2008] 890)Natural Science Foundation of Zhejiang Province,China (Grant No Y407188)
文摘The electronic structure and magnetism of eskolaite are studied by using first-principles calculations where the on-site Coulomb interaction and the exchange interaction are taken into account and the LSDA+U method is used. The calculated energies of magnetic configurations are very well fitted by the Heisenberg Hamiltonian with interactions in five neighbour shells; interaction with two nearest neighbours is found to be dominant. The Neel temperature is calculated in the spin-3/2 pair-cluster approximation. It is found that the measurements are in good agreement with the calculations of lattice parameters, density of states, band gap, local magnetic moment, and the Neel temperature for the values of U and J that are close to those obtained within the constrained occupation method. The band gap is of the Mott-Hubbard type.
基金Project supported by the National Basic Research Program of China (Grant No. 2010CB833102)the National Natural ScienceFoundation of China (Grant No. 10974244)
文摘Ternary yttrium chromium sulfide,Y2CrS4,prepared by the solid-state reaction of Y2S3,Cr,and S,was found to exhibit an antiferromagnetic transition at about 64 K.The X-ray diffraction pattern at 300 K was refined with space group Pca2 1,and the structure parameters were determined to be a = 12.51 Ab = 7.53A,and c = 12.49A,We investigated the magnetotransport properties,and observed negative colossal magnetoresistance reaching up to 2.5 × 10^ 4 % in the semiconducting compound of Y2CrS4.
基金This work was supported by the State Key Laboratory of Structural Chemistry, the Ministry of Science and Technology of China (001CB108906) the National Natural Science Foundation of China (20333070)
文摘The self-assembly reactions of M^ⅡCl2 (M = Ni, Co) with the flexible bix ligand [bix = 1,4-bis(imidazole-1-ylmethyl)benzene] yielded a 2D network [N^Ⅲ(bix)2Cl2]n 1 and a 1D chain [Co^Ⅱ(bix)Cl2]n 2. Their crystal structures have been determined by X-ray single-crystal diffraction analysis. Complex 1 characters a two-dimensional grid-type structure and crystallizes in monoclinic, space group P21/c with a = 7.7231(7), b = 12.7787(9), c = 13.9374(13)A, β = 105.419(4)°, C28H28Cl2N8Ni, Mr = 606.19, Ζ = 2, V = 1326.0(2)A^3, Dc = 1.518 g/cm^3, μ = 0.969 mm^-1, F(000) = 628, R = 0.0429 and wR = 0.0783 for 2503 observed reflections (Ⅰ〉 2σ(Ⅰ)). Compound 2 is a one-dimensional chain and crystallizes in orthorhombic, space group Pbca with a = 11.3696(6), b = 10.2128(6), c = 14.4943(9) (A), C14H14Cl2CoN4, Mr = 368.12, Z = 4, V = 1683.01(17)A^3, Dc = 1.453 g/cm^3, μ = 1.334 mm^-1, F(000) = 748, R = 0.0317 and wR = 0.0800 for 1778 observed reflections (Ⅰ〉 2σ(Ⅰ)). Magnetic properties of the title complexes were also investigated.
基金Financially supported by the Education Department of Jiangxi Province(No.JXJG-14-10-6)Jiangxi Science and Technology Normal University
文摘Treatment of a heptadentate ligand 2,2'-(((pyridine-2,6-diyl-bis(methylene))- bis((pyridin-2-ylmethyl)azanediyl))bis(methylene))diphenol (H2L) possessing pyridinyl- and phenolate groups, with three equivalents of Cu(C104)2·6H2O in methanol under base conditions, gave rise to a hexanuclear cluster complex [Cu6L2(OH)4](C104)4·4MeCN·0.5MeOH (1). Complex 1 crystallizes in triclinic, space group Pi with a = 12.068(12), b = 12.567(12), c = 16.279(16) A, α = 105.694(12), β = 93.631(13), γ = 112.017(11)°, V= 2166(4) A3, Z = 1,μ= 1.651 mm^-1, Dc = 1.599 Mg/m^3, T = 296(2) K, C74.5H795N14O24.5Cl4Cu6, Mr = 2086.12, F(000) = 1062.5, S = 1.061, R = 0.0521 and wR = 0.1270. In the cation of complex 1, the six copper cores are arranged into a two-parallel three-site strings configuration with each metal exhibits a slightly distorted square-pyramidal geometry, resulting from the connection of donor pyridinyi nitrogen and phenolate oxygen atoms in ligand H2L, and/or the oxygen donors in hydroxyl groups. In addition, magnetic susceptibility measurements revealed complex 1 displayed antiferromagnetic coupling.
基金Supported by NNSFC(No.21171129 and 21173157)the Program for Innovative Research Team in University of Tianjin(TD12-5038)the National Training Programs of Innovation and Entrepreneurship for Undergraduates(201410065025)
文摘Two 4,5-dichlorophthalate-based metal complexes, {[Cu(bipy)(dcpa)].H2O}n, (1) and {[Cu2Coipy)2(Hdcpa)3]·H2O·C2H5OH.Hdcpa} (2, H2dcpa = 4,5-dichlorophthalic acid and bipy = 2,2'-bipyridine), were synthesized and characterized structurally and magnetically. Complex 1 is of orthorhombic system, space group Fdd2 with a = 20.5821(8), b = 20.9013(12), c = 17.0270(7) A, V= 7324.9(6) A3, Dc = 1.707 g/cm3, Mr = 470.74, Z = 16, F(000) = 3792, p = 1.519 mm^-1, the final R = 0.0223 and wR = 0.0549 for 9239 observed reflections with I〉 2σ(I). Complex 2 crystallizes in triclinic, space group P1 with a = 14.1439(12), b = 14.2981(12), c = 15.1054(14) A, a = 72.121(2), β = 77.703(2),γ = 81.829(2)°, V= 2830.9(4) A3, Dc = 1.689 g/cm3, M,. = 1439.55, Z = 2, F(000) = 1452,μ = 1.207 mm^-1, the final R = 0.0536 and wR = 0.0981 for 16422 observed reflections with 1 〉 2σ(I). Complex 1 exhibits a diamond-like framework with centrosymmetric binuclear subunits extended by pairs of doubly deprotonated dcpa2- linkers. By contrast, 2 is an asymmetric binuclear entity bridged by carboxylate group of mono deprotonated Hdcpa- ligands. Weak anti- and ferromagnetic interactions are respectively mediated in the carboxylate aggregated binuclear subunits of 1 and 2.
文摘Abstract: a novel tlhree dimenslonal network complex polymer,namely, GdF6 (CN)6. 4H2O; has been synthesized from water solntion of gadollinium chloride and potassium ferricyanide, The complex erystalized in the monoclinie system, space group c2; with a=12. 759 (6) b=7. 404 (1). c=13. 564 (5) A,z=4. β=90. 22 (3), Mr=441. 33,De=2. 28g/cm2, μ(Mo Kcr)=38. 36cm-1, F (000)=832, R=0. 065 for 1048 independent observed reflections. The coordinated of Fe (111) ion and Gd (111) ion are distorted octahedron and 4-capped trigonal prism, respectively. The varible- temperature magnetlc suscepttbility of the complex was measured over 4.2-300K, giving the exchange intergral 2J=-138.2cm-1,and indlcation that a mediate antiferromagnetic spinsxchange interaction between the Fe (111) ions and the Gd (111) lons within oach binuclear unit.