Owing to the distinctive structural characteristics,vanadium nitride(VN)is highly regarded as a catalyst for oxygen reduction reaction(ORR)in zinc-air batteries(ZABs).However,VN exhibits limited intrinsic ORR activity...Owing to the distinctive structural characteristics,vanadium nitride(VN)is highly regarded as a catalyst for oxygen reduction reaction(ORR)in zinc-air batteries(ZABs).However,VN exhibits limited intrinsic ORR activity due to the weak adsorption ability to O-containing species.Here,the S-doped VN anchored on N,S-doped multi-dimensional carbon(S-VN/Co/NS-MC)was constructed using the solvothermal and in-situ doping methods.Incorporating sulfur atoms into VN species alters the electron spin state of vanadium in the S-VN/Co/NS-MC for regulating the adsorption energy of vanadium sites to oxygen molecules.The introduced sulfur atoms polarize the V 3d_(z)^(2) electrons,shifting spin-down electrons closer to the Fermi level in the S-VN/Co/NS-MC.Consequently,the introduction of sulfur atoms into VN species enhances the adsorption energy of vanadium sites for oxygen molecules.The*OOH dissociation transitions from being unspontaneous on the VN surface to a spontaneous state on the S-doped VN surface.Then,the ORR barrier on the S-VN/Co/NS-MC surface is reduced.The S-VN/Co/NS-MC demonstrates a higher half-wave potential and limiting current density compared to the VN/Co/N-MC.The S-VN/Co/NS-MC-based liquid ZABs display a power density of 195.7 m W cm^(-2),a specific capacity of 815.7 m A h g^(-1),and a cycling stability exceeding 250 h.The S-VN/Co/NS-MC-based flexible ZABs are successfully employed to charge both a smart watch and a mobile phone.This approach holds promise for advancing the commercial utilization of VN-based catalysts in ZABs.展开更多
The crystal structure of CaSrFe<sub>0.75</sub>Co<sub>0.75</sub>Mn<sub>0.5</sub>O<sub>6−δ</sub> is investigated through neutron diffraction techniques in this study. The...The crystal structure of CaSrFe<sub>0.75</sub>Co<sub>0.75</sub>Mn<sub>0.5</sub>O<sub>6−δ</sub> is investigated through neutron diffraction techniques in this study. The material is synthesized using a solid-state synthesis method at a temperature of 1200˚C. Neutron diffraction data is subjected to Rietveld refinement, and a comparative analysis with X-ray diffraction (XRD) data is performed to unravel the structural details of the material. The findings reveal that the synthesized material exhibits a cubic crystal structure with a Pm-3m phase. The neutron diffraction results offer valuable insights into the arrangement of atoms within the lattice, contributing to a comprehensive understanding of the material’s structural properties. This research enhances our knowledge of CaSrFe0.75</sub>Co0.75</sub>Mn0.5</sub>O6−δ</sub>, with potential implications for its applications in various technological and scientific domains.展开更多
The contactin-associated protein (Caspr) family participates in nerve excitation and conduction, and neurotransmitter release in myelinated axons. We analyzed the structures and functions of the Caspr family- CNTNA...The contactin-associated protein (Caspr) family participates in nerve excitation and conduction, and neurotransmitter release in myelinated axons. We analyzed the structures and functions of the Caspr family- CNTNAP1 (Casprl), CNTNAP2 (Caspr2), CNTNAP3 (Caspr3), CNTNAP4 (Caspr4) and CNTNAP5 (Caspr5), Casprl-5 is not only involved in the formation of myelinated axons, but also participates in maintaining the stability of adjacent connections. Casprl participates in the formation, differentiation, and proliferation of neurons and astrocytes, and in motor control and cognitive function. We also analyzed the relationship between the Caspr family and neurodegenerative diseases, multiple sclerosis, and autoimmune encephalitis. However, the effects of Caspr on disease course and prognosis remain poorly understood. The effects of Caspr on disease diagnosis and treatment need further investigation.展开更多
Concrete has traditionally been regarded as a durable material requiring little or no maintenance. However, over the past several decades, a number of durability related problems have emerged and stimulated research i...Concrete has traditionally been regarded as a durable material requiring little or no maintenance. However, over the past several decades, a number of durability related problems have emerged and stimulated research into the factors relating to concrete durability globally. The challenge now facing practicing engineers is how to design and build structures that not only satisfy the specified structural requirements, but also achieve the performance levels required from a durability standpoint. Research works on concrete structural durability have been widely reported in the literature over the last several decades. In this paper, reviews of four stages of research work on durability, i e, environments, materials, components, and structures, were presented. Afterwards, the key scientific issues in this field were also pointed out.展开更多
Genes homologous to members of the MRP gene family in Caenorhabditis elegans are important in drug resistance.To further explore the molecular mechanism of drug resistance in pine wood nematode(Bursaphelenchus xylophi...Genes homologous to members of the MRP gene family in Caenorhabditis elegans are important in drug resistance.To further explore the molecular mechanism of drug resistance in pine wood nematode(Bursaphelenchus xylophilus),we used bioinformatics approaches to analyze genomic data for B.xylophilus and identified Bx-MRP genes.We predicted the structure and function of the genes and encoded proteins.Using bioinformatics programs to predict and analyze various properties of the predicted proteins,including hydrophobicity,transmembrane regions,phosphorylation sites,and topologically isomeric structures,of these Bx-MRP genes,we determined that they function in transmembrane transport.From the results of RT-qPCR,the Bx-MRP family members confer significant differential resistance to different drug treatments.After treatment with different concentrations of emamectin benzoate,avermectin and matrine,the expression of each gene increased with increasing drug concentrations,indicating that the family members play a positive role in the regulation of multidrug resistance.展开更多
This article uses data from censuses since 1982 to reveal changes in the family structure of rural China since the launch of reform and opening up and against the backdrop of institutional relocation,social transforma...This article uses data from censuses since 1982 to reveal changes in the family structure of rural China since the launch of reform and opening up and against the backdrop of institutional relocation,social transformation and an aging population.Since the advent of reform and opening up,rural family structure and its changes can be divided into two phases.Before the 1990 s,the household contract responsibility system was implemented,labor in rural villages was still mainly engaged in farming,and the number of nuclear families remained stable with a steady rise.After the 1990 s,as reform progress deepened,substantial numbers of young and middle-aged laborers in rural villages began to relocate into non-farming sectors and aging in rural villages rose.As those born in the early days of the family planning policy gradually matured,family structure was directly affected and changed in new ways and forms not seen before.Vocational divisions of labor among the parents of young families and married offspring emerged and the significance of cooperation for family economy and daily life between parents and offspring rose in importance.Also,the prevalence of immediate families with three generations climbed while the standard nuclear families declined,the ratio of middle-aged couples with young children that worked outside the home increased,the function of middle-aged and senior parents in the upbringing of infants and children enhanced,and the commonness of incomplete family types such as only grandparents with grandchildren increased.During this phase,the number of seniors living alone surged to the point of becoming a matter worthy of attention.展开更多
The electronic and lattice structures of poly (phenylene vinylene) (PPV) are studied theoretically. Both the electron-electron and electron-phonon interactions are taken into account in the Pariser-Parr-Pople model. T...The electronic and lattice structures of poly (phenylene vinylene) (PPV) are studied theoretically. Both the electron-electron and electron-phonon interactions are taken into account in the Pariser-Parr-Pople model. The electronic band and the lattice structure of the ground state and the polaronic state are calculated by means of the unrestricted Hartree-Fock method. In the ground state, there exist eight bands in PPV including four valence bands and four conduction bands, and the benzenes can be considered to be rigid. The polaron induces the split of energy bands. There are four localized electronic states within the energy gap. The defect of the polaron appears to extend over about 5 units. The benzenes are strongly affected by the electron-phonon interaction. Our calculation for the energy band structure of the ground and polaron states are consistent with experimental absorption spectra. The results of our calculation show that the electron-phonon and inter-site electron-electron interactions play an important role in determining the electronic and lattice structures.展开更多
A new ternary alkali metal chalcogenide halide, K3SI, has been synthesized by solid state reaction method and structurally characterized by X-ray crystallography. The crystal belongs to hexagonal, space group P63cm wi...A new ternary alkali metal chalcogenide halide, K3SI, has been synthesized by solid state reaction method and structurally characterized by X-ray crystallography. The crystal belongs to hexagonal, space group P63cm with a = 11.699(I ), c = 5.8279(9) A°, Mr = 276.26, V = 690.8(1 )A°^ 3, Z = 6, D, = 3.985 g/cm^3, F(000) = 756, μ = 9.913 mm^-1, S = 1.004, R = 0.0719 and wR = 0.2204. The title compound is the first example containing S anion in the ternary alkali metal chalcogenide halides family M3QX (M = alkali metal, Q = chalcogenide, X - halide), which crystallizes in the hexagonal anti-perovskite structure type.展开更多
The solid state thermal reaction of benzil with 3-methyl-1-phenyl-5-pyrazolone gave the title compound 1 (C_24H_18N_2O_2) and its isomer 2. The crystal structure of the title compound has been determined by X-ray anal...The solid state thermal reaction of benzil with 3-methyl-1-phenyl-5-pyrazolone gave the title compound 1 (C_24H_18N_2O_2) and its isomer 2. The crystal structure of the title compound has been determined by X-ray analysis. The crystal belongs to monoclinic system, space group P2_1/n, with cell parameters a = 7. 479 ( 1 ), b =16. 992(1), c=15. 165(1) A , β= 100. 99(1)°, V= 1891. 9 A ̄3, M_r=366. 42, Z=4, D_c= 1. 286 g/cm ̄3, μ= 6. 236 cm ̄-1, F(000) = 768. In the molecule of 1, benzoyl group and CO group of five-member ring are in cis-positions, the interaction of oxygen atoms leads to the noncoplanarity.展开更多
The majority of extant reptiles are oviparous and produce eggs with three major components:embryo,yolk,and eggshell.The eggshell is species-specific and more diverse in squamate reptiles than in other amniote taxa.Her...The majority of extant reptiles are oviparous and produce eggs with three major components:embryo,yolk,and eggshell.The eggshell is species-specific and more diverse in squamate reptiles than in other amniote taxa.Here,we study the crystal structure,chemical composition,and bonding states of the eggshell of the green crested lizard Bronchocela cristatella.X-ray diffractometer(XRD)analysis showed the existence of two clearly defined and distinguishable crystalline phases,aragonite and calcite.Using the XRD data and a unit cell refinement routine,we identified two sets of cell parameters:a=4.956 A,b=7.965 A,and c=5.734 A for the aragonite phase;a=4.987 A,b=4.987 A,and c=17.056 A for the calcite structure.We used x-ray photoelectron spectroscopy to examine detailed elemental composition and bonding states and found that the eggshell was composed primarily of elements C,N,Ca,and O,with C,N and O bonded to various types of hybridization in the protein of the eggshell membrane.The Ca:C:O ratio for the calcium carbonate yielded a value of-7:8:21,which is close to the expected stoichiometric value of CaCO3.展开更多
Further evidences show that most mining dynamic disasters are mainly oc- curred nearby NNE and near SN geological structures.In-situ stress measurement in Fuxin basin shows that the orientation of major compressed str...Further evidences show that most mining dynamic disasters are mainly oc- curred nearby NNE and near SN geological structures.In-situ stress measurement in Fuxin basin shows that the orientation of major compressed stress is near EW.At this stress field,geological structures with deferent strike have deferent stress state and dis- place mode.NNE and near SN geological structures are compressed to thrust and come into being high stress zone.NWW and NEE geological structures are tensile to separate and not prone to being low stress zone.NW structure is intervenient of them.So NEE and near SN structures are easy to occurre mining dynamic disasters and NWW and NEE structures is 'safety' comparatively.The mining dynamic disaster is controlled by stress state of geologic structure,which is determined by its strike.展开更多
[Cu_(0.84)Au_(0.16)(PPh_3)_2(SC(Ph)NHPh)Cl]·0.5CS_2=,Mr=895.79,monoclinic,space group P2_1/a,a=17.231(3),b=14.611(2),c=18.000(3) ,β=105.56(2)°,V=4365(1) ~3, Z=4,D_c=1.37g/cm^3.,λ(MoK_α)=0.71073 ,μ=12.15c...[Cu_(0.84)Au_(0.16)(PPh_3)_2(SC(Ph)NHPh)Cl]·0.5CS_2=,Mr=895.79,monoclinic,space group P2_1/a,a=17.231(3),b=14.611(2),c=18.000(3) ,β=105.56(2)°,V=4365(1) ~3, Z=4,D_c=1.37g/cm^3.,λ(MoK_α)=0.71073 ,μ=12.15cm^(-1),F(000)=1855,R=0.052, R_W=0.045 for 3930 observed reflections with Ⅰ>1.5σ(Ⅰ).The central metal atom has a dis. torted tetrahedral geometry with bond lengths Cu-S=2.384(2) (Au-S=2.389(4)), Cu-Cl=2.481(3)(Au-Cl=2.474(1))and Cu-P=2.269(2)-2.289(2)(Au-P=2.270(4)-2.279(4)) .展开更多
VO 2 thin films with good switching properties were prepared by controlling the annealing time and the annealing temperature in a vacuum system. The structural, optical and electrical properties of the samples were ch...VO 2 thin films with good switching properties were prepared by controlling the annealing time and the annealing temperature in a vacuum system. The structural, optical and electrical properties of the samples were characterized by using XRD、XPS、UV-VIS and electrical measurements. The switching parameters of VO 2 thin film were investigated too. The results indicate that before and after phase transition the resistance of VO 2 thin films changes about three orders of magnitude, the variation of film transmittance of 40 % has been carried out with the absorptivity switching velocity of about 0.260 7 /min at 900 nm . The structural property of samples has been improved but the phase-transition properties have been decreased by increasing the annealing time and annealing temperature. The valence of V ions and the structure of samples have great effect on phase transition properties of VO 2 thin films. Discussion on the effects of annealing time and annealing temperature on the phase-transition temperature and hysteresis width shows that the best reasonable annealing time and annealing temperature can be achieved.展开更多
Children from two-parent families have better outcomes,on average,than children from single-parent families.Yet the mechanisms associated with family structure and family process that produce divergent outcomes are le...Children from two-parent families have better outcomes,on average,than children from single-parent families.Yet the mechanisms associated with family structure and family process that produce divergent outcomes are less well understood.Based on data from the 2011-2015 National Health Interview Survey(N=26,783),I leverage the case of military families with deployment and examine the impacts of parenting quality,economic capital,and social capital on children’s psychological well-being.The regression results show that single parenthood produced by divorce,separation,and birth out of wedlock leads to worse child outcomes than single parenthood produced by military deployment,and family process partially explains the variation in children’s well-being beyond family structure.Married families,military or civilian,deployed or not,enjoy advantages that translate into positive child outcomes.Marriage,therefore,emerges as the primary axis of inequality,and maintaining a healthy marriage better promotes children’s well-being.展开更多
The structure of aggregation state and isothermal crystallization behavior of Nylon-1010 have been studied by WAXD, DSE, Variance-Range Function and density measurement. The results show that crystallization of Nylon-...The structure of aggregation state and isothermal crystallization behavior of Nylon-1010 have been studied by WAXD, DSE, Variance-Range Function and density measurement. The results show that crystallization of Nylon-1010 has the most suitable annealing temperature, the crystals of the Nxlon-1010 are two-dimension heterogeneous nucleation. Both low treatment temperature and high crystallization te, temperature are disadvantageous for Nylon-1010 crystal growth.展开更多
We carry out detailed momentum-dependent and temperature-dependent measurements on Bi_2Sr_2CaCu_2O_(8+δ)(Bi2212) superconductor in the superconducting and pseudogap states by super-high resolution laser-based an...We carry out detailed momentum-dependent and temperature-dependent measurements on Bi_2Sr_2CaCu_2O_(8+δ)(Bi2212) superconductor in the superconducting and pseudogap states by super-high resolution laser-based angleresolved photoemission spectroscopy. The precise determination of the superconducting gap for the nearly optimally doped Bi2212(T_c= 91 K) at low temperature indicates that the momentum-dependence of the superconducting gap deviates from the standard d-wave form(cos(2Φ)). It can be alternatively fitted by including a high-order term(cos(6Φ)) in which the next nearest-neighbor interaction is considered. We find that the band structure near the antinodal region smoothly evolves across the pseudogap temperature without a signature of band reorganization which is distinct from that found in Bi_2Sr_2CuO_(6+δ) superconductors. This indicates that the band reorganization across the pseudogap temperature is not a universal behavior in cuprate superconductors.These results provide new insights in understanding the nature of the superconducting gap and pseudogap in high-temperature cuprate superconductors.展开更多
Theclustering phenomenon,in which nucleons are arranged intoparticles(4 He nuclei)within a nuclear system,is one of the most intriguing aspects of nuclear structure.It has been observed in various light nuclei,such as...Theclustering phenomenon,in which nucleons are arranged intoparticles(4 He nuclei)within a nuclear system,is one of the most intriguing aspects of nuclear structure.It has been observed in various light nuclei,such as^(8)Be,^(12)C,^(16)O,and^(20)Ne,and is responsible for many exotic and fascinating phenomena,such as the Hoyle state in^(12)C,which plays an essential role in stellar nucleosynthesis[1-6]as well as in heavy-ion collisions[7-9].展开更多
One new ternary europium gallium sulfide, Eu2Ga2S5, has been synthesized by a facile solid-state route with boron as the reducing reagent. It crystallizes in the orthorhombic space group Pbca, with a = 11.976(1), b ...One new ternary europium gallium sulfide, Eu2Ga2S5, has been synthesized by a facile solid-state route with boron as the reducing reagent. It crystallizes in the orthorhombic space group Pbca, with a = 11.976(1), b = 11.074(1), c = 17.446(1)A^°, V = 1650.6(3)A^°^3, and Z = 8. Its 3-D structure is built by the connection between EuS 7 monocapped trigonal prisms and GaS 4 tetrahedra, and the latter connect with each other to form layer-like slabs. Its optical energy gap is determined to be 2.17 eV, which is also verified by the electronic band structure calculation.展开更多
A series of nominal composition Ti/(ZrO2)x(RuO2)l-x (0.1≤x≤0.9) coatings chan-ged in 10% steps was deposited on titanium substrate from RuCl3·nH2O and ZrCl4 containing ethanol solution by thermal decompos...A series of nominal composition Ti/(ZrO2)x(RuO2)l-x (0.1≤x≤0.9) coatings chan-ged in 10% steps was deposited on titanium substrate from RuCl3·nH2O and ZrCl4 containing ethanol solution by thermal decomposition method. The X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM) and electrochemical tests were performed to clarify the effects of ZrO2 content on the structure and capacitive property of Ti/(ZrO2)x(RuO2)l-x. The results show that by adding ZrO2 into the coatings the degree of crystallization of RuO2 decreases. The specific capacitance firstly increases and then deceases with the increase of ZrO2 content in the mixed oxide coatings. The film of Ti/(ZrO2)0.6(RuO2)0.4 consisting of amorphous matrix and fine nano-crystalline RuO2 (about 4 nm) has the maximum specific capacitance of 713.27 F/g(RuO2).展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.22178148,22278193,22075113)the Jiangsu Province and Education Ministry Co-Sponsored Synergistic Innovation Center of Modern Agricultural Equipment(Grant No.XTCX2029)+1 种基金a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX22_3691)。
文摘Owing to the distinctive structural characteristics,vanadium nitride(VN)is highly regarded as a catalyst for oxygen reduction reaction(ORR)in zinc-air batteries(ZABs).However,VN exhibits limited intrinsic ORR activity due to the weak adsorption ability to O-containing species.Here,the S-doped VN anchored on N,S-doped multi-dimensional carbon(S-VN/Co/NS-MC)was constructed using the solvothermal and in-situ doping methods.Incorporating sulfur atoms into VN species alters the electron spin state of vanadium in the S-VN/Co/NS-MC for regulating the adsorption energy of vanadium sites to oxygen molecules.The introduced sulfur atoms polarize the V 3d_(z)^(2) electrons,shifting spin-down electrons closer to the Fermi level in the S-VN/Co/NS-MC.Consequently,the introduction of sulfur atoms into VN species enhances the adsorption energy of vanadium sites for oxygen molecules.The*OOH dissociation transitions from being unspontaneous on the VN surface to a spontaneous state on the S-doped VN surface.Then,the ORR barrier on the S-VN/Co/NS-MC surface is reduced.The S-VN/Co/NS-MC demonstrates a higher half-wave potential and limiting current density compared to the VN/Co/N-MC.The S-VN/Co/NS-MC-based liquid ZABs display a power density of 195.7 m W cm^(-2),a specific capacity of 815.7 m A h g^(-1),and a cycling stability exceeding 250 h.The S-VN/Co/NS-MC-based flexible ZABs are successfully employed to charge both a smart watch and a mobile phone.This approach holds promise for advancing the commercial utilization of VN-based catalysts in ZABs.
文摘The crystal structure of CaSrFe<sub>0.75</sub>Co<sub>0.75</sub>Mn<sub>0.5</sub>O<sub>6−δ</sub> is investigated through neutron diffraction techniques in this study. The material is synthesized using a solid-state synthesis method at a temperature of 1200˚C. Neutron diffraction data is subjected to Rietveld refinement, and a comparative analysis with X-ray diffraction (XRD) data is performed to unravel the structural details of the material. The findings reveal that the synthesized material exhibits a cubic crystal structure with a Pm-3m phase. The neutron diffraction results offer valuable insights into the arrangement of atoms within the lattice, contributing to a comprehensive understanding of the material’s structural properties. This research enhances our knowledge of CaSrFe0.75</sub>Co0.75</sub>Mn0.5</sub>O6−δ</sub>, with potential implications for its applications in various technological and scientific domains.
基金supported by a grant from the Instructional Program of Science and Technology Bureau of Wuxi City of China,No.0302B010507130039PB
文摘The contactin-associated protein (Caspr) family participates in nerve excitation and conduction, and neurotransmitter release in myelinated axons. We analyzed the structures and functions of the Caspr family- CNTNAP1 (Casprl), CNTNAP2 (Caspr2), CNTNAP3 (Caspr3), CNTNAP4 (Caspr4) and CNTNAP5 (Caspr5), Casprl-5 is not only involved in the formation of myelinated axons, but also participates in maintaining the stability of adjacent connections. Casprl participates in the formation, differentiation, and proliferation of neurons and astrocytes, and in motor control and cognitive function. We also analyzed the relationship between the Caspr family and neurodegenerative diseases, multiple sclerosis, and autoimmune encephalitis. However, the effects of Caspr on disease course and prognosis remain poorly understood. The effects of Caspr on disease diagnosis and treatment need further investigation.
基金Funded by the National Natural Science Foundation of China (No.50538070)
文摘Concrete has traditionally been regarded as a durable material requiring little or no maintenance. However, over the past several decades, a number of durability related problems have emerged and stimulated research into the factors relating to concrete durability globally. The challenge now facing practicing engineers is how to design and build structures that not only satisfy the specified structural requirements, but also achieve the performance levels required from a durability standpoint. Research works on concrete structural durability have been widely reported in the literature over the last several decades. In this paper, reviews of four stages of research work on durability, i e, environments, materials, components, and structures, were presented. Afterwards, the key scientific issues in this field were also pointed out.
基金supported by the National Key Research and Development Program of China(2017YFD0600101).
文摘Genes homologous to members of the MRP gene family in Caenorhabditis elegans are important in drug resistance.To further explore the molecular mechanism of drug resistance in pine wood nematode(Bursaphelenchus xylophilus),we used bioinformatics approaches to analyze genomic data for B.xylophilus and identified Bx-MRP genes.We predicted the structure and function of the genes and encoded proteins.Using bioinformatics programs to predict and analyze various properties of the predicted proteins,including hydrophobicity,transmembrane regions,phosphorylation sites,and topologically isomeric structures,of these Bx-MRP genes,we determined that they function in transmembrane transport.From the results of RT-qPCR,the Bx-MRP family members confer significant differential resistance to different drug treatments.After treatment with different concentrations of emamectin benzoate,avermectin and matrine,the expression of each gene increased with increasing drug concentrations,indicating that the family members play a positive role in the regulation of multidrug resistance.
文摘This article uses data from censuses since 1982 to reveal changes in the family structure of rural China since the launch of reform and opening up and against the backdrop of institutional relocation,social transformation and an aging population.Since the advent of reform and opening up,rural family structure and its changes can be divided into two phases.Before the 1990 s,the household contract responsibility system was implemented,labor in rural villages was still mainly engaged in farming,and the number of nuclear families remained stable with a steady rise.After the 1990 s,as reform progress deepened,substantial numbers of young and middle-aged laborers in rural villages began to relocate into non-farming sectors and aging in rural villages rose.As those born in the early days of the family planning policy gradually matured,family structure was directly affected and changed in new ways and forms not seen before.Vocational divisions of labor among the parents of young families and married offspring emerged and the significance of cooperation for family economy and daily life between parents and offspring rose in importance.Also,the prevalence of immediate families with three generations climbed while the standard nuclear families declined,the ratio of middle-aged couples with young children that worked outside the home increased,the function of middle-aged and senior parents in the upbringing of infants and children enhanced,and the commonness of incomplete family types such as only grandparents with grandchildren increased.During this phase,the number of seniors living alone surged to the point of becoming a matter worthy of attention.
文摘The electronic and lattice structures of poly (phenylene vinylene) (PPV) are studied theoretically. Both the electron-electron and electron-phonon interactions are taken into account in the Pariser-Parr-Pople model. The electronic band and the lattice structure of the ground state and the polaronic state are calculated by means of the unrestricted Hartree-Fock method. In the ground state, there exist eight bands in PPV including four valence bands and four conduction bands, and the benzenes can be considered to be rigid. The polaron induces the split of energy bands. There are four localized electronic states within the energy gap. The defect of the polaron appears to extend over about 5 units. The benzenes are strongly affected by the electron-phonon interaction. Our calculation for the energy band structure of the ground and polaron states are consistent with experimental absorption spectra. The results of our calculation show that the electron-phonon and inter-site electron-electron interactions play an important role in determining the electronic and lattice structures.
基金We gratefully acknowledge the financial support of the NSF of China (20131020), the NSF for Distinguished Young Scientist of China (20425104) and the NSF of Fujian Province (Z0513020).
文摘A new ternary alkali metal chalcogenide halide, K3SI, has been synthesized by solid state reaction method and structurally characterized by X-ray crystallography. The crystal belongs to hexagonal, space group P63cm with a = 11.699(I ), c = 5.8279(9) A°, Mr = 276.26, V = 690.8(1 )A°^ 3, Z = 6, D, = 3.985 g/cm^3, F(000) = 756, μ = 9.913 mm^-1, S = 1.004, R = 0.0719 and wR = 0.2204. The title compound is the first example containing S anion in the ternary alkali metal chalcogenide halides family M3QX (M = alkali metal, Q = chalcogenide, X - halide), which crystallizes in the hexagonal anti-perovskite structure type.
文摘The solid state thermal reaction of benzil with 3-methyl-1-phenyl-5-pyrazolone gave the title compound 1 (C_24H_18N_2O_2) and its isomer 2. The crystal structure of the title compound has been determined by X-ray analysis. The crystal belongs to monoclinic system, space group P2_1/n, with cell parameters a = 7. 479 ( 1 ), b =16. 992(1), c=15. 165(1) A , β= 100. 99(1)°, V= 1891. 9 A ̄3, M_r=366. 42, Z=4, D_c= 1. 286 g/cm ̄3, μ= 6. 236 cm ̄-1, F(000) = 768. In the molecule of 1, benzoyl group and CO group of five-member ring are in cis-positions, the interaction of oxygen atoms leads to the noncoplanarity.
文摘The majority of extant reptiles are oviparous and produce eggs with three major components:embryo,yolk,and eggshell.The eggshell is species-specific and more diverse in squamate reptiles than in other amniote taxa.Here,we study the crystal structure,chemical composition,and bonding states of the eggshell of the green crested lizard Bronchocela cristatella.X-ray diffractometer(XRD)analysis showed the existence of two clearly defined and distinguishable crystalline phases,aragonite and calcite.Using the XRD data and a unit cell refinement routine,we identified two sets of cell parameters:a=4.956 A,b=7.965 A,and c=5.734 A for the aragonite phase;a=4.987 A,b=4.987 A,and c=17.056 A for the calcite structure.We used x-ray photoelectron spectroscopy to examine detailed elemental composition and bonding states and found that the eggshell was composed primarily of elements C,N,Ca,and O,with C,N and O bonded to various types of hybridization in the protein of the eggshell membrane.The Ca:C:O ratio for the calcium carbonate yielded a value of-7:8:21,which is close to the expected stoichiometric value of CaCO3.
基金the Major State Basic Research Development Program of China"973"Program(2005CB221501)the General Project of the National Natural Science Foundation of PR China(50574047)
文摘Further evidences show that most mining dynamic disasters are mainly oc- curred nearby NNE and near SN geological structures.In-situ stress measurement in Fuxin basin shows that the orientation of major compressed stress is near EW.At this stress field,geological structures with deferent strike have deferent stress state and dis- place mode.NNE and near SN geological structures are compressed to thrust and come into being high stress zone.NWW and NEE geological structures are tensile to separate and not prone to being low stress zone.NW structure is intervenient of them.So NEE and near SN structures are easy to occurre mining dynamic disasters and NWW and NEE structures is 'safety' comparatively.The mining dynamic disaster is controlled by stress state of geologic structure,which is determined by its strike.
基金Project supported by the National Natural Science Foundation of China
文摘[Cu_(0.84)Au_(0.16)(PPh_3)_2(SC(Ph)NHPh)Cl]·0.5CS_2=,Mr=895.79,monoclinic,space group P2_1/a,a=17.231(3),b=14.611(2),c=18.000(3) ,β=105.56(2)°,V=4365(1) ~3, Z=4,D_c=1.37g/cm^3.,λ(MoK_α)=0.71073 ,μ=12.15cm^(-1),F(000)=1855,R=0.052, R_W=0.045 for 3930 observed reflections with Ⅰ>1.5σ(Ⅰ).The central metal atom has a dis. torted tetrahedral geometry with bond lengths Cu-S=2.384(2) (Au-S=2.389(4)), Cu-Cl=2.481(3)(Au-Cl=2.474(1))and Cu-P=2.269(2)-2.289(2)(Au-P=2.270(4)-2.279(4)) .
文摘VO 2 thin films with good switching properties were prepared by controlling the annealing time and the annealing temperature in a vacuum system. The structural, optical and electrical properties of the samples were characterized by using XRD、XPS、UV-VIS and electrical measurements. The switching parameters of VO 2 thin film were investigated too. The results indicate that before and after phase transition the resistance of VO 2 thin films changes about three orders of magnitude, the variation of film transmittance of 40 % has been carried out with the absorptivity switching velocity of about 0.260 7 /min at 900 nm . The structural property of samples has been improved but the phase-transition properties have been decreased by increasing the annealing time and annealing temperature. The valence of V ions and the structure of samples have great effect on phase transition properties of VO 2 thin films. Discussion on the effects of annealing time and annealing temperature on the phase-transition temperature and hysteresis width shows that the best reasonable annealing time and annealing temperature can be achieved.
文摘Children from two-parent families have better outcomes,on average,than children from single-parent families.Yet the mechanisms associated with family structure and family process that produce divergent outcomes are less well understood.Based on data from the 2011-2015 National Health Interview Survey(N=26,783),I leverage the case of military families with deployment and examine the impacts of parenting quality,economic capital,and social capital on children’s psychological well-being.The regression results show that single parenthood produced by divorce,separation,and birth out of wedlock leads to worse child outcomes than single parenthood produced by military deployment,and family process partially explains the variation in children’s well-being beyond family structure.Married families,military or civilian,deployed or not,enjoy advantages that translate into positive child outcomes.Marriage,therefore,emerges as the primary axis of inequality,and maintaining a healthy marriage better promotes children’s well-being.
文摘The structure of aggregation state and isothermal crystallization behavior of Nylon-1010 have been studied by WAXD, DSE, Variance-Range Function and density measurement. The results show that crystallization of Nylon-1010 has the most suitable annealing temperature, the crystals of the Nxlon-1010 are two-dimension heterogeneous nucleation. Both low treatment temperature and high crystallization te, temperature are disadvantageous for Nylon-1010 crystal growth.
基金Supported by the National Key Research and Development Program of China under Grant No 2016YFA0300300the National Natural Science Foundation of China under Grant No 11334010+1 种基金the National Basic Research Program of China under Grant No2015CB921300the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB07020300
文摘We carry out detailed momentum-dependent and temperature-dependent measurements on Bi_2Sr_2CaCu_2O_(8+δ)(Bi2212) superconductor in the superconducting and pseudogap states by super-high resolution laser-based angleresolved photoemission spectroscopy. The precise determination of the superconducting gap for the nearly optimally doped Bi2212(T_c= 91 K) at low temperature indicates that the momentum-dependence of the superconducting gap deviates from the standard d-wave form(cos(2Φ)). It can be alternatively fitted by including a high-order term(cos(6Φ)) in which the next nearest-neighbor interaction is considered. We find that the band structure near the antinodal region smoothly evolves across the pseudogap temperature without a signature of band reorganization which is distinct from that found in Bi_2Sr_2CuO_(6+δ) superconductors. This indicates that the band reorganization across the pseudogap temperature is not a universal behavior in cuprate superconductors.These results provide new insights in understanding the nature of the superconducting gap and pseudogap in high-temperature cuprate superconductors.
文摘Theclustering phenomenon,in which nucleons are arranged intoparticles(4 He nuclei)within a nuclear system,is one of the most intriguing aspects of nuclear structure.It has been observed in various light nuclei,such as^(8)Be,^(12)C,^(16)O,and^(20)Ne,and is responsible for many exotic and fascinating phenomena,such as the Hoyle state in^(12)C,which plays an essential role in stellar nucleosynthesis[1-6]as well as in heavy-ion collisions[7-9].
基金supported by Yangzhou Engineering Technology Research Center of Petrochemical New Materials(YZM2015086)Yangzhou Science and Technology Bureau(YZ2016269)
文摘One new ternary europium gallium sulfide, Eu2Ga2S5, has been synthesized by a facile solid-state route with boron as the reducing reagent. It crystallizes in the orthorhombic space group Pbca, with a = 11.976(1), b = 11.074(1), c = 17.446(1)A^°, V = 1650.6(3)A^°^3, and Z = 8. Its 3-D structure is built by the connection between EuS 7 monocapped trigonal prisms and GaS 4 tetrahedra, and the latter connect with each other to form layer-like slabs. Its optical energy gap is determined to be 2.17 eV, which is also verified by the electronic band structure calculation.
基金Supported by the National High Technology Research and Development Projects (863) of China (2007AA03Z325)the Natural Science Foundation of China (50472002)+1 种基金Provincial Science Foundation of Fujian (2009J05116)the program for Innovative Research Team in Fuzhou University
文摘A series of nominal composition Ti/(ZrO2)x(RuO2)l-x (0.1≤x≤0.9) coatings chan-ged in 10% steps was deposited on titanium substrate from RuCl3·nH2O and ZrCl4 containing ethanol solution by thermal decomposition method. The X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM) and electrochemical tests were performed to clarify the effects of ZrO2 content on the structure and capacitive property of Ti/(ZrO2)x(RuO2)l-x. The results show that by adding ZrO2 into the coatings the degree of crystallization of RuO2 decreases. The specific capacitance firstly increases and then deceases with the increase of ZrO2 content in the mixed oxide coatings. The film of Ti/(ZrO2)0.6(RuO2)0.4 consisting of amorphous matrix and fine nano-crystalline RuO2 (about 4 nm) has the maximum specific capacitance of 713.27 F/g(RuO2).