In the paper we introduce the notions of the separation factor ~ and give a representive of metric projection on an n-codimension subspace （or an affine set） under certain conditions in Banach space. Further, we obt...In the paper we introduce the notions of the separation factor ~ and give a representive of metric projection on an n-codimension subspace （or an affine set） under certain conditions in Banach space. Further, we obtain the distance formula from any point x to a finite n-codimension subspace. Results extend and improve the corresponding results in Hilbert space.展开更多
The chemical vapor deposition(CVD)method has been widely used to synthesize high-quality two-dimensional(2D)materials.However,just one type of product can be synthesized by general CVD at one time.Here,we demonstrate ...The chemical vapor deposition(CVD)method has been widely used to synthesize high-quality two-dimensional(2D)materials.However,just one type of product can be synthesized by general CVD at one time.Here,we demonstrate a one-step CVD method to simultaneously grow two types of products.Importantly,the products can be completely separated by selecting the deposition region.In detail,the controllable and completely separable growth forα-GeTe and Te nanosheets was realized by using one precursor-GeTe powder through the atmospheric pressure CVD(APCVD)approach.High crystal quality of the as-grownα-GeTe nansosheets and Te nanosheets have been proved by the high-resolution transmission electron microscopy(HRTEM)characterization.Further,the field-effect-transistor(FET)based onα-GeTe nanosheet manifests that the as-grownαGeTe nanosheet is a degenerate semiconductor due to the intrinsic Ge vacancies.Additionally,Te-based FET devices indicate that the good electrical performance of the as-grown Te nanosheet,such as high mobility of 900 cm2·V^(−1)·s^(−1)(at room temperature),high on/off ratio of>106(at 77 K),and good air-stability.The developed one-step CVD method shows the huge potentials for high-efficiency and high-quality material growth.展开更多
文摘In the paper we introduce the notions of the separation factor ~ and give a representive of metric projection on an n-codimension subspace （or an affine set） under certain conditions in Banach space. Further, we obtain the distance formula from any point x to a finite n-codimension subspace. Results extend and improve the corresponding results in Hilbert space.
基金supported by the National Key Research and Development Program of China(No.2018YFA0703700)the National Natural Science Foundation of China(Nos.91964203 and 61974036)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB44000000)the CAS Key Laboratory of Nanosystem and Hierarchical Fabrication.The authors also gratefully acknowledge the support of Youth Innovation Promotion Association CAS。
文摘The chemical vapor deposition(CVD)method has been widely used to synthesize high-quality two-dimensional(2D)materials.However,just one type of product can be synthesized by general CVD at one time.Here,we demonstrate a one-step CVD method to simultaneously grow two types of products.Importantly,the products can be completely separated by selecting the deposition region.In detail,the controllable and completely separable growth forα-GeTe and Te nanosheets was realized by using one precursor-GeTe powder through the atmospheric pressure CVD(APCVD)approach.High crystal quality of the as-grownα-GeTe nansosheets and Te nanosheets have been proved by the high-resolution transmission electron microscopy(HRTEM)characterization.Further,the field-effect-transistor(FET)based onα-GeTe nanosheet manifests that the as-grownαGeTe nanosheet is a degenerate semiconductor due to the intrinsic Ge vacancies.Additionally,Te-based FET devices indicate that the good electrical performance of the as-grown Te nanosheet,such as high mobility of 900 cm2·V^(−1)·s^(−1)(at room temperature),high on/off ratio of>106(at 77 K),and good air-stability.The developed one-step CVD method shows the huge potentials for high-efficiency and high-quality material growth.
