Carbon graphite is a crystalline form of carbon consisting of layers of hexagonal carbon atoms arranged in a two-dimensional “graphene” structure. Graphene layers are stacked on top of each other, forming a three-di...Carbon graphite is a crystalline form of carbon consisting of layers of hexagonal carbon atoms arranged in a two-dimensional “graphene” structure. Graphene layers are stacked on top of each other, forming a three-dimensional structure with a high degree of anisotropy. The carbon atoms within each layer are linked together by strong covalent bonds, creating a strong, stable lattice structure. However, the layers themselves are held together by weak van der Waals forces, enabling them to slide easily over each other. The properties of carbon graphite are highly dependent on the orientation and alignment of the graphene layers. When the layers are aligned parallel to each other, the material exhibits high strength and stiffness along the alignment direction, but is weaker and more flexible in other directions. Carbon graphite is used in a variety of applications where high strength, rigidity and electrical conductivity are required. Some common applications include electrical contacts, electric motor brushes, and as a structural material in aerospace and defense applications. The aim of our work is to describe the structure of graphite, its physical and chemical properties and its applications.展开更多
In this study, Al/p-Si and Al/Bi4Ti3O12/p-Si structures are fabricated and their interface states （Nss）, the values of series resistance （Rs）, and AC electrical conductivity （σac） are obtained each as a functio...In this study, Al/p-Si and Al/Bi4Ti3O12/p-Si structures are fabricated and their interface states （Nss）, the values of series resistance （Rs）, and AC electrical conductivity （σac） are obtained each as a function of temperature using admit- tance spectroscopy method which includes capacitance-voltage （C-V） and conductance-voltage （G-V） measurements. In addition, the effect of interfacial Bi4Ti3012 （BTO） layer on the performance of the structure is investigated. The voltage- dependent profiles of Nss and Rs are obtained from the high-low frequency capacitance method and the Nicollian method, respectively. Experimental results show that Nss and Rs, as strong functions of temperature and applied bias voltage, each exhibit a peak, whose position shifts towards the reverse bias region, in the depletion region. Such a peak behavior is attributed to the particular distribution of Nss and the reordering and restructuring of Nss under the effect of temperature. The values of activation energy （Ea）, obtained from the slope of the Arrhenius plot, of both structures are obtained to be bias voltage-independent, and the Ea of the metal-ferroelectric-semiconductor （MFS） structure is found to be half that of the metal-semiconductor （MS） structure. Furthermore, other main electrical parameters, such as carrier concentration of acceptor atoms （NA）, built-in potential （Vbi）, Fermi energy （EF）, image force barrier lowering （△φb）, and barrier height （φb）, are extracted using reverse bias C 2-V characteristics as a function of temperature.展开更多
Dense sintered bodies of proton conducting BaZrO3 (BZ) and Y-doped BaZrO3 (BZ-Y) were obtained at 1600℃ for a short sintering time of 5 hours, by the addition of NiO as a sintering promotion agent. The relative densi...Dense sintered bodies of proton conducting BaZrO3 (BZ) and Y-doped BaZrO3 (BZ-Y) were obtained at 1600℃ for a short sintering time of 5 hours, by the addition of NiO as a sintering promotion agent. The relative density and grain growth of samples, Ni-doped BaZrO3 (BZ-N) and Ni, Y co-doped BaZrO3 (BZ-NY), were increased with increasing Ni addition. The sinterability of BZ-NY was greatly improved just to add only 0.6 mol% Ni and the relative density of this sample was more than 98%, in contrast to that of 60% at most for BZ-Y without Ni addition. Electrical conductivity of BZ-NY added Ni 1.0 mol%, BaZr0.91Ni0.01Y0.08O3-α, was more than 10-3 S.cm-2 at 900℃?in a wet 1% hydrogen atmosphere, which value was 10 times higher than that of BZ-Y. In addition, the kind of electrical conduction carrier and an ionic transport number were also examined by employing various concentration cells. It was found that the proton conduction was dominant for both BZ-N and BZ-NY samples, although BZ-NY showed scarcely oxygenion conduction approximately 10% in a high temperature range higher than 800℃. From these results, as mall amount of Ni addition found to be effective for improvement of both the sinterability and the electrical conductivity.展开更多
以盐酸甜菜碱(Betaine·HCl)、乙二醇(EG)和六水合硫酸镍(NiSO_4·6H_2O)制备的Betaine·HCl-6EG-nNiSO_4·6H_2O低共熔离子液体为电解液,在碳钢(CS)基体上电沉积出平整致密的金属镍镀层.采用旋转黏度计和电导率仪分别...以盐酸甜菜碱(Betaine·HCl)、乙二醇(EG)和六水合硫酸镍(NiSO_4·6H_2O)制备的Betaine·HCl-6EG-nNiSO_4·6H_2O低共熔离子液体为电解液,在碳钢(CS)基体上电沉积出平整致密的金属镍镀层.采用旋转黏度计和电导率仪分别测定了其黏度和电导率.在测试条件下,其黏度为3.918~55.19 m Pa·s,电导率为1.109~0.199 S/m.循环伏安测试结果表明Betaine·HCl-6EG-nNiSO_4·6H_2O(n=0.071)低共熔离子液体中Ni^(2+)在CS电极上的电化学还原过程可以描述为Ni^(2+)→Ni^0,其起始还原电位为-0.56 V.对CS基体上的沉积层进行XRD和EDAS测试,分析结果表明镀层为具有面心立方晶型结构的金属镍.SEM结果表明得到的镍镀层晶粒细小致密且均匀.镀层截面组织金相照片和线性扫描能谱图表明沿CS基体各处均得到厚度分布均匀且与基体结合良好的镍镀层,其厚度约为11μm.展开更多
Since LiOsO_3 was discovered, obtaining easy-accessible polar metals for research and applications has been challenging. In this paper, we present a multilayer design strategy, which is configured as ferroelectric lay...Since LiOsO_3 was discovered, obtaining easy-accessible polar metals for research and applications has been challenging. In this paper, we present a multilayer design strategy, which is configured as ferroelectric layer/carrier reservoir layer/isolation layer/substrate, for obtaining polar metals by electrostatically doping a strained ferroelectric material in a more effective way. In the proposed configuration, both 1 unit-cell thick BaTiO_3 and PbTiO_3 exhibited considerable Ti off-centering with various strains,which should extend the applicability of ferroelectric-based polar metals in ultra-thin devices. Moreover, engineered by the compressive strain and the BaTiO_3 thickness, the design strategy effectively achieved polar metallicity and dimensionalitytunable electronic states associated with the modulation of highly anisotropic properties such as electrical and electronic thermal conductivity, which may be helpful for designing ultra-thin, ultrafast, and low-power switch devices.展开更多
The electrical conductivities of the dunite from the Qinghai-Xizang (Tibetan) Plateau were measured with the impedance spectra method at 1.0-4.0 GPa and 643-1093 K. The experimental results indicated that activation e...The electrical conductivities of the dunite from the Qinghai-Xizang (Tibetan) Plateau were measured with the impedance spectra method at 1.0-4.0 GPa and 643-1093 K. The experimental results indicated that activation enthalpies of the dunite are smaller than 0.9 eV, the conduction mechanism in dunite may be attributed to the mixed electrical conduction involving grain interiors and boundaries. On the basis of the results of this experiment, we can deduce that there exists cold mantle in the area of Gaize-Lugu in the Qinghai-Xizang (Tibetan) Plateau by reverse methods from the magnetotelluric sounding data (conductivity-depths profile) available for western Tibet. The result provides the present cold mantle viewpoint with strong proof on the basis of high temperature and pressure experiments.展开更多
非化学计量微米氧化硅(SiO_(x))由于其高理论容量和低成本,有望成为锂离子电池石墨负极材料的替代品.然而,SiO_(x)的实际应用仍然受到其较差的固有导电性和循环过程中明显的体积变化的阻碍.在本工作中,为了同时解决这些问题,我们使用可...非化学计量微米氧化硅(SiO_(x))由于其高理论容量和低成本,有望成为锂离子电池石墨负极材料的替代品.然而,SiO_(x)的实际应用仍然受到其较差的固有导电性和循环过程中明显的体积变化的阻碍.在本工作中,为了同时解决这些问题,我们使用可规模化的溶剂热和热还原方法制备了具有TiO_(1-y)Ny-C涂层的SiO_(x)基负极材料(SiO_(x)@TiON-C).我们通过系统性研究发现,TiO_(1-y)Ny-C涂层可以适应SiO_(x)循环过程中大的体积变化且有效提高其导电性.因此,SiO_(x)@TiON-C负极具有突出的储锂性能.具体而言,SiO_(x)@TiON-C负极可以在500 mA g^(-1)的电流密度下循环500圈后仍保持750.2 mA h g^(-1)的优异可逆容量,75.1%的初始库仑效率和优异的倍率性能.这项工作为促进下一代锂离子电池微米SiO_(x)基负极材料的实际商业化提供了一种很有前途的方法.展开更多
文摘Carbon graphite is a crystalline form of carbon consisting of layers of hexagonal carbon atoms arranged in a two-dimensional “graphene” structure. Graphene layers are stacked on top of each other, forming a three-dimensional structure with a high degree of anisotropy. The carbon atoms within each layer are linked together by strong covalent bonds, creating a strong, stable lattice structure. However, the layers themselves are held together by weak van der Waals forces, enabling them to slide easily over each other. The properties of carbon graphite are highly dependent on the orientation and alignment of the graphene layers. When the layers are aligned parallel to each other, the material exhibits high strength and stiffness along the alignment direction, but is weaker and more flexible in other directions. Carbon graphite is used in a variety of applications where high strength, rigidity and electrical conductivity are required. Some common applications include electrical contacts, electric motor brushes, and as a structural material in aerospace and defense applications. The aim of our work is to describe the structure of graphite, its physical and chemical properties and its applications.
基金supported by the Science and Technology Major Project of Fujian Province,China (2022HZ027006)Fujian Provincial Science and Technology Planning Project (2022I0006)+1 种基金Quanzhou Municipal Science and Technology Major Project,China (2022GZ7)the National Natural Science Foundation of China (62274036)。
文摘In this study, Al/p-Si and Al/Bi4Ti3O12/p-Si structures are fabricated and their interface states （Nss）, the values of series resistance （Rs）, and AC electrical conductivity （σac） are obtained each as a function of temperature using admit- tance spectroscopy method which includes capacitance-voltage （C-V） and conductance-voltage （G-V） measurements. In addition, the effect of interfacial Bi4Ti3012 （BTO） layer on the performance of the structure is investigated. The voltage- dependent profiles of Nss and Rs are obtained from the high-low frequency capacitance method and the Nicollian method, respectively. Experimental results show that Nss and Rs, as strong functions of temperature and applied bias voltage, each exhibit a peak, whose position shifts towards the reverse bias region, in the depletion region. Such a peak behavior is attributed to the particular distribution of Nss and the reordering and restructuring of Nss under the effect of temperature. The values of activation energy （Ea）, obtained from the slope of the Arrhenius plot, of both structures are obtained to be bias voltage-independent, and the Ea of the metal-ferroelectric-semiconductor （MFS） structure is found to be half that of the metal-semiconductor （MS） structure. Furthermore, other main electrical parameters, such as carrier concentration of acceptor atoms （NA）, built-in potential （Vbi）, Fermi energy （EF）, image force barrier lowering （△φb）, and barrier height （φb）, are extracted using reverse bias C 2-V characteristics as a function of temperature.
文摘Dense sintered bodies of proton conducting BaZrO3 (BZ) and Y-doped BaZrO3 (BZ-Y) were obtained at 1600℃ for a short sintering time of 5 hours, by the addition of NiO as a sintering promotion agent. The relative density and grain growth of samples, Ni-doped BaZrO3 (BZ-N) and Ni, Y co-doped BaZrO3 (BZ-NY), were increased with increasing Ni addition. The sinterability of BZ-NY was greatly improved just to add only 0.6 mol% Ni and the relative density of this sample was more than 98%, in contrast to that of 60% at most for BZ-Y without Ni addition. Electrical conductivity of BZ-NY added Ni 1.0 mol%, BaZr0.91Ni0.01Y0.08O3-α, was more than 10-3 S.cm-2 at 900℃?in a wet 1% hydrogen atmosphere, which value was 10 times higher than that of BZ-Y. In addition, the kind of electrical conduction carrier and an ionic transport number were also examined by employing various concentration cells. It was found that the proton conduction was dominant for both BZ-N and BZ-NY samples, although BZ-NY showed scarcely oxygenion conduction approximately 10% in a high temperature range higher than 800℃. From these results, as mall amount of Ni addition found to be effective for improvement of both the sinterability and the electrical conductivity.
文摘以盐酸甜菜碱(Betaine·HCl)、乙二醇(EG)和六水合硫酸镍(NiSO_4·6H_2O)制备的Betaine·HCl-6EG-nNiSO_4·6H_2O低共熔离子液体为电解液,在碳钢(CS)基体上电沉积出平整致密的金属镍镀层.采用旋转黏度计和电导率仪分别测定了其黏度和电导率.在测试条件下,其黏度为3.918~55.19 m Pa·s,电导率为1.109~0.199 S/m.循环伏安测试结果表明Betaine·HCl-6EG-nNiSO_4·6H_2O(n=0.071)低共熔离子液体中Ni^(2+)在CS电极上的电化学还原过程可以描述为Ni^(2+)→Ni^0,其起始还原电位为-0.56 V.对CS基体上的沉积层进行XRD和EDAS测试,分析结果表明镀层为具有面心立方晶型结构的金属镍.SEM结果表明得到的镍镀层晶粒细小致密且均匀.镀层截面组织金相照片和线性扫描能谱图表明沿CS基体各处均得到厚度分布均匀且与基体结合良好的镍镀层,其厚度约为11μm.
基金supported by the National Key Basic Research Program of China(Grant No.2014CB921001)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB07030200)+2 种基金the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(Grant No.QYZDJ-SSW-SLH020)the National Key Research and Development Program of China(Grant No.2017YFA0303604)the National Natural Science Foundation of China(Grant Nos.11721404,and11674385)
文摘Since LiOsO_3 was discovered, obtaining easy-accessible polar metals for research and applications has been challenging. In this paper, we present a multilayer design strategy, which is configured as ferroelectric layer/carrier reservoir layer/isolation layer/substrate, for obtaining polar metals by electrostatically doping a strained ferroelectric material in a more effective way. In the proposed configuration, both 1 unit-cell thick BaTiO_3 and PbTiO_3 exhibited considerable Ti off-centering with various strains,which should extend the applicability of ferroelectric-based polar metals in ultra-thin devices. Moreover, engineered by the compressive strain and the BaTiO_3 thickness, the design strategy effectively achieved polar metallicity and dimensionalitytunable electronic states associated with the modulation of highly anisotropic properties such as electrical and electronic thermal conductivity, which may be helpful for designing ultra-thin, ultrafast, and low-power switch devices.
基金This work was supported by the National Climbing Program (Grant No. 95-P-39) under the auspices of the National Key Project on the Tibetan Plateau (Grant No. G1998040800) the National Natu- ral Science Foundation of China (Grant No. 49674221).
文摘The electrical conductivities of the dunite from the Qinghai-Xizang (Tibetan) Plateau were measured with the impedance spectra method at 1.0-4.0 GPa and 643-1093 K. The experimental results indicated that activation enthalpies of the dunite are smaller than 0.9 eV, the conduction mechanism in dunite may be attributed to the mixed electrical conduction involving grain interiors and boundaries. On the basis of the results of this experiment, we can deduce that there exists cold mantle in the area of Gaize-Lugu in the Qinghai-Xizang (Tibetan) Plateau by reverse methods from the magnetotelluric sounding data (conductivity-depths profile) available for western Tibet. The result provides the present cold mantle viewpoint with strong proof on the basis of high temperature and pressure experiments.
基金supported by the National Natural Science Foundation of China (52102225 and 51874104)the Start-up Research Grant of Guangdong University of Technology,China (220413729)。
文摘非化学计量微米氧化硅(SiO_(x))由于其高理论容量和低成本,有望成为锂离子电池石墨负极材料的替代品.然而,SiO_(x)的实际应用仍然受到其较差的固有导电性和循环过程中明显的体积变化的阻碍.在本工作中,为了同时解决这些问题,我们使用可规模化的溶剂热和热还原方法制备了具有TiO_(1-y)Ny-C涂层的SiO_(x)基负极材料(SiO_(x)@TiON-C).我们通过系统性研究发现,TiO_(1-y)Ny-C涂层可以适应SiO_(x)循环过程中大的体积变化且有效提高其导电性.因此,SiO_(x)@TiON-C负极具有突出的储锂性能.具体而言,SiO_(x)@TiON-C负极可以在500 mA g^(-1)的电流密度下循环500圈后仍保持750.2 mA h g^(-1)的优异可逆容量,75.1%的初始库仑效率和优异的倍率性能.这项工作为促进下一代锂离子电池微米SiO_(x)基负极材料的实际商业化提供了一种很有前途的方法.
