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Chloride-intercalated continuous chemical vapor deposited graphene film with discrete adlayers

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Nano Research 2018年第1期11卷 440-448页

作者： qiao Chen Li Zhang hongwei Zhu State Key Lab of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China Center for Nano and Micro Mechanics Tsinghua University Beijing 100084 China

Heteroatom doping can open the bandgap and increase the carrier density, thus extending the applications of graphene. Iron chloride （FeC13） intercalation has proven to be an efficient method for the heavy doping of graphene. In this study, we prepared continuous chemical vapor deposited graphene （CVD-G） consisting of hexagonal adlayer domains to study the FeC13 intercalation. The structure of the FeC13-treated CVD-G was easily characterized via atomic force microscopy because of the change in the interlayer distance. FeC13 crystals several nanometers thick were integrated with the graphene surface, and FeC13 layer flakes were intercalated between the CVD-G adlayers. The G-band position and two-dimensional band shape in the Raman spectra confirmed the intercalation of the FeC13 between the graphene layers. The FeCI~ intercalation increased the electrical conductivity of the CVD-G with a well-maintained transmittance, which could be beneficial for a sensitive photodetector.

关键词： intercalation graphene chemical vapor deposition iron chloride

半-Hilbert空间中的几类数值半径不等式

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内蒙古大学学报（自然科学版） 2024年第6期55卷 403-411页

作者：赵佳佳乔宏伟海国君内蒙古大学数学科学学院呼和浩特010021 内蒙古师范大学数学科学学院呼和浩特010022

研究了由正算子A诱导的半内积〈·,·〉_(A)生成的半-Hilbert空间中的数值半径不等式。利用幂平均不等式等改进了已有的半-Hilbert空间中的数值半径的上界与下界,并与已有的不等式进行了比较,在最后的结论中也得到了等号成立的条件。

关键词： A-数值半径不等式正算子半-Hilbert空间

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先天性松果体囊肿CT及MRI诊断分析

中国煤炭工业医学杂志 2012年第2期15卷 186-188页

作者：邱立军原小军乔宏伟包头医学院第一附属医院CT、磁共振室内蒙古包头市014010

目的探讨CT及MRI对先天性松果体囊肿的诊断价值。方法对26例先天性松果体囊肿CT及MRI表现进行回顾性分析。结果在CT、MRI上囊肿表现为圆形或椭圆形囊性病灶,囊壁薄而均匀,光滑完整;囊内容物CT值与脑脊液接近或稍高于脑脊液;在MRI上囊肿... 详细信息

目的探讨CT及MRI对先天性松果体囊肿的诊断价值。方法对26例先天性松果体囊肿CT及MRI表现进行回顾性分析。结果在CT、MRI上囊肿表现为圆形或椭圆形囊性病灶,囊壁薄而均匀,光滑完整;囊内容物CT值与脑脊液接近或稍高于脑脊液;在MRI上囊肿呈长T1长T2水样信号,增强扫描囊壁无或轻度强化。结论 MRI能准确发现松果体囊性病变,对先天性松果体囊肿的诊断价值优于CT,是其首选的影像学检查方法。

关键词：松果体囊肿 X线计算机体层摄影术磁共振成像

Experimental Study of Turbulent Boundary Layers on Groove/Smooth Flat Surfaces

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Journal of Thermal Science 2005年第3期14卷 193-197页

作者： hongwei MA qiao TIAN Hui WU School of Jet Propulsion Beijing University of Aeronautics and Astronautics Beijing 100083 China

This paper presents an experimental investigation of the turbulent boundary layers on both groove and smooth flat surfaces. The flow structures were shown in a water tunnel using the hydrogen-bubble flow visualization technique. The measurement results indicate that: (1) the grooves can effectively reduce accumulation of low-speed fluids, decrease the number of the low-speed streaks and depress oscillation of the streaks in the sublayer; (2) the grooves can restrain forming of the horseshoe vortices in the buffer region; (3) the grooves bate oscillation and kinking of the quasi-streamwise vortices and restrain production of the hairpin vortices and the ring vortices, reducing both frequency and intensity of the turbulence bursting; (4) the grooves directly affect the flow structures in the sublayer of the boundary layer and then modulate the flow field up to the buffer region and the logarithmic region by restraining development and interaction of the vortices.

关键词： streamwise groove turbulent boundary layer drag reduction mechanism coherent structure hydrogen-bubble flow visualization

Efficient optimization method for variable-specific-impulse low-thrust trajectories with shutdown constraint

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Science China(Technological Sciences) 2022年第3期65卷 581-594页

作者： JIA FeiDa qiao Dong HAN hongwei LI XiangYu School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Key Laboratory of Autonomous Navigation and Control for Deep Space Exploration Ministry of Industry and Information TechnologyBeijing 100081China

This paper develops a sequential convex programming(SCP)-based method to solve the minimum-fuel variable-specific-impulse low-thrust transfer problem considering shutdown constraint,with emphasize on improving the computational *** variable parameter engine is more applicable for many low-thrust scenarios,therefore,both a continuously variable model and a ladder variable model are ***,the original problem is convexified by processing the constraint feasible domain,which is composed of the nonlinear dynamic equations and second-order equality constraint,into convex ***,the approximation is generated to close the optimal solution of the low-thrust problem by iteratively solving the convexified ***,the switching self-detection and adaptive node refinement methods are presented,which can improve the accuracy of the solution and accelerate the convergence during the approximation process and is especially necessary and effective in the scenarios with shutdown *** numerical simulations,the comparison with the homotopic approach shows that the proposed method only needs 4%computational time as that of the homotopic approach,and two variable-specificimpulse examples further demonstrate the effectiveness and efficiency of the proposed method.

关键词： low-thrust trajectory variable-specific-impulse shutdown constraint sequential convex programming switching self-detection and adaptive node refinement

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软弱围岩大断面隧道爆破设计

青海交通科技 2020年第5期32卷 113-117页

作者：高建坡王海乔宏伟王世鹏中交二公局东萌工程有限公司西安710000

随着我国公路隧道的大发展,软弱围岩地质条件下的隧道工程项目逐年增加。大屋基隧道属软弱围岩大断面隧道,在爆破开挖时容易出现超欠挖现象,爆破效果不理想。本文依托仁遵高速大屋基特长隧道新建工程,对开挖过程中的上台阶光面爆破的爆... 详细信息

随着我国公路隧道的大发展,软弱围岩地质条件下的隧道工程项目逐年增加。大屋基隧道属软弱围岩大断面隧道,在爆破开挖时容易出现超欠挖现象,爆破效果不理想。本文依托仁遵高速大屋基特长隧道新建工程,对开挖过程中的上台阶光面爆破的爆破参数、炮孔布置等进行了参数选取与优化,试验后发现:爆破后隧道轮廓较为光滑、平整,围岩表面孔炮孔痕迹明显,炮孔半痕率达到了85%以上,超欠挖现象明显减少。

关键词：隧道开挖软弱围岩光面爆破参数优化