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MBR平板膜中气泡运动的水力特征的数值分析

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环境工程学报 2020年第2期14卷 414-422页

作者：曹迎晨 SONNENBURG ale.ander urban Wilhelm 达姆施塔特工业大学IWAR研究所达姆施塔特64287 IWW水研究中心莱茵-美因研究所比贝斯海姆64584

膜污染是膜生物反应器系统在污水和废水处理应用中最主要的问题之一。针对这一问题,通过计算流体动力学(CFD)仿真模拟,研究了单个气泡以及气泡群在平板膜中的水力学特征,包括气泡速度和膜表面剪切应力等,以达到优化膜组件几何特征和运... 详细信息

膜污染是膜生物反应器系统在污水和废水处理应用中最主要的问题之一。针对这一问题,通过计算流体动力学(CFD)仿真模拟,研究了单个气泡以及气泡群在平板膜中的水力学特征,包括气泡速度和膜表面剪切应力等,以达到优化膜组件几何特征和运行条件的目的。模拟结果表明,对于单个气泡而言,随着气泡尺寸的增加,气泡上升速度开始随着直径的增加而升高,在气泡直径为4 mm时,其可达到最大值,随后随着直径的增加反而降低。此外,对于直径为4 mm的气泡,随着膜间隙距离的增加,气泡上升速度明显呈升高的趋势,而剪切应力呈现下降趋势。考虑到实际运行中的膜堵塞问题,建议在平板膜组件中使用7 mm的膜间距,以适当增强膜表面剪切应力。气泡群的模拟结果表明,当膜间液相上升流速较大时,气相和液相所产生的剪切应力相当。而当膜间液相上升流速较小时,气相产生的剪切应力占主导。以上研究结果可为膜生物反应器的设计及运行提供参考。

关键词： CFD模拟平板膜膜污染剪切力单气泡气泡群

Sensitivity analysis of parameters and contrasting performance of ground filtering algorithms with UAV photogrammetry-based and LiDAR point clouds

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International Journal of Digital Earth 2020年第12期13卷 1672-1694页

作者： Petr Klápště Michal Fogl Vojtěch Barták Kateřina Gdulová Rudolf urban Vítězslav Moudrý Department of Applied Geoinformatics and Spatial Planning Faculty of Environmental SciencesCzech University of Life Sciences PragueKamýcká129Praha-Suchdol16500Czech Republic Department of Special Geodesy Faculty of Civil EngineeringCzech Technical University in PraguePragueCzech Republic

Most ground filtering algorithms are primarily designed for airborne LiDAR point cloud processing and their successful use in identifying ground points from photogrammetric point clouds remains *** compared six ground filtering algorithms implemented in Metashape,ArcGIS,CloudCompare,LAStools,and *** used UAV photogrammetry-based(acquired under leaf-off conditions)and airborne LiDAR(leaf-on)point clouds of the same area to:(i)compare accuracy of generated DTMs;(ii)evaluate the effect of vegetation density and terrain slope on filtering accuracy;and(iii)assess which algorithm parameters have the greatest effect on the filtering *** results show that the performance of filtering algorithms was affected by the point cloud type,terrain slope and vegetation *** results were generally better for LiDAR(RMSE 0.13–0.19 m)than for photogrammetric(RMSE 0.19–0.23 m)point *** behavior in varying vegetation and terrain conditions was consistent for LiDAR point ***,when applied on photogrammetric point clouds,the algorithms’behavior was inconsistent,especially in areas of steep slope(except for the Progressive Triangulated Irregular Network in LAStools).Parameters related to the selection of the initial minimum elevation ground points were the most influential in all algorithms and point clouds.

关键词： DTM filtering LiDAR point cloud spoil heap UAV

Direct generation of linearly polarized photon emission with designated orientations from site-controlled InGaN quantum dots

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Light(Science & Applications) 2014年第1期3卷 323-329页

作者： Anders Lundskog Chih-Wei Hsu K Fredrik Karlsson Supaluck Amloy Daniel Nilsson urban Forsberg Per Olof Holtz Erik Janzen Department of Physics Chemistry and Biology(IFM) Linkoping UniversitySE-58183 LinkopingSweden Department of Physics Faculty of ScienceThaksin UniversityPhattalung 93110Thailand

Semiconductor quantum dots(QDs)have been demonstrated viable for efficient light emission applications,in particular for the emission of single photons on ***,the preparation of QDs emitting photons with predefined and deterministic polarization vectors has proven *** to linearly polarized photons is essential for various *** this report,a novel concept to directly generate linearly-polarized photons is *** concept is based on InGaN QDs grown on top of elongated GaN hexagonal pyramids,by which the predefined elongation determines the polarization vectors of the emitted photons from the *** growth scheme should allow fabrication of ultracompact arrays of photon emitters,with a controlled polarization direction for each individual emitter.

关键词： GaN InGaN photoluminescence polarized emission quantum dot

DEVELOPMENT AND VIBRATION ANALYSIS OF CERAMIC ROCKER ARM

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Chinese Journal of Mechanical Engineering 1995年第4期8卷 309-312页

作者： Yang Helai Cheng Geng Su Feng(Tianjin Institute of urban Engineering)

A ceramic rocker arm is proposed. Test for ICE performance and numerical analysis ofvalve system were earried out. The results show that ceramic rocker arm can replace ordinarysteel ones and meet the requiements of IC... 详细信息

关键词： Ceramic rocker Vibration

Effects of Comprehensive High-speed Transportation Hubs on Spatial Structure of urban Development:A Case Study on Changsha-Zhuzhou-Xiangtan Area

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China City Planning Review 2011年第4期20卷 26-32页

作者： ZHANG Guohua, LI Linglan,LI Caige Department of urban Transport, China Academy of urban Planning & Design Department of urban Transport, China Academy of urban Planning & Design

This paper, by studying the mechanism of the spatial restructuring of urban development and the effects of comprehensive high-speed transportation hubs on it, analyzes the development trends of comprehensive high-speed transportation in Changsha-Zhuzhou-Xiangtan Area and the impacts of the growing urban area centered on comprehensive high-speed transportation hubs, like airport and high-speed railway station, on the urban development of this area. It also proposes some strategies for the spatial restructuring of Changsha-Zhuzhou-Xiangtan Area in view of the development of the comprehensive high-speed transportation hubs, like Huanghua Airport and Wuhan-Guangzhou High-speed Railway Station.

关键词： comprehensive high-speed transportation hub spatia

Herbst矫治器伴头帽牵引治疗安氏Ⅱ类错

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华西口腔医学杂志 2004年第1期22卷 46-48,51页

作者：杜熹 urban Hgg 四川大学华西口腔医院正畸科四川成都610041 香港大学牙学院正畸专业

目的　研究Herbst矫治器伴头帽牵引逐步前伸下颌对安氏Ⅱ类错的矫治效果。方法　治疗组 2 2例患者 ,对照组 31例患者。治疗组患者均按治疗的前 6个月、后 6个月 (平均 )及维持期 6个月 ,3个阶段治疗并拍摄头侧位定位片观察。对照组患... 详细信息

目的　研究Herbst矫治器伴头帽牵引逐步前伸下颌对安氏Ⅱ类错的矫治效果。方法　治疗组 2 2例患者 ,对照组 31例患者。治疗组患者均按治疗的前 6个月、后 6个月 (平均 )及维持期 6个月 ,3个阶段治疗并拍摄头侧位定位片观察。对照组患者拍摄 2次头侧位定位片 ,其间间隔 6个月。结果　平均治疗 12个月后的疗效是抑制上颌骨生长、刺激下颌骨生长并降低下面高。与对照组相比 ,对上颌骨的抑制作用在治疗的前后 6个月均有统计学意义 ,对下颌骨的刺激作用仅在治疗前 6个月有统计学意义 ,对下面高的降低作用仅在治疗后 6个月有统计学意义。维持阶段上下基骨关系不变而对下面高的降低作用进一步加强。结论　Herbst矫治器伴头帽牵引能有效地矫治安氏Ⅱ类错 ,对上颌骨的作用随时间的增加而加强。

关键词： Herbst矫治器头帽牵引治疗安氏Ⅱ类错He 上颌骨

Severity of dentofacial deformity, the motivations and the outcome of surgery in skeletal Class Ⅲ patients

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Chinese Medical Journal 2002年第7期115卷 1031-1034页

作者：周彦恒 urban Hgg ABakr MRabie 香港大学牙医学院

Objective To study the relationship between severity of skeletal Class Ⅲ malocclusion and the patient's emotional status, as well as motivation for seeking surgical correction and satisfaction with the outcome of the surgery Methods One hundred and forty consecutive Chinese patients with skeletal Class Ⅲ malocclusion who had been treated with a combined orthodontic and surgical approach were studied Sixty seven percent (40 male. and 54 female.) responded to a questionnaire Fifty four percent had two jaw deformities, 32% mandibular hyperplasia and 14% maxillary hypoplasia Surgical procedures: 77% received two jaw surgeries, 15% maxillary advancement and 8% mandibular setback This was a retrospective study based on questionnaires with numerical scale.ranked answers (0: not at all; 1: a little; 2: moderately; 3: quite a bit; and 4: extremely) Results ANB angle was significantly negatively correlated with feelings about the nickname related to their facial problems (embarrassment: r =-0 30, P <0 01; worn out r =-0 32, P <0 01; angry r = -0 24, P <0 05) ANB angle also had a significant negative correlation with the reasons for having the surgery (pressure from their friends: r =-0 21, P <0 05, and referred by physician: r =-0 24, P <0 05) Changes in life style as a result of surgery were significantly negatively correlated with the ANB angle before treatment, positive influence on relationships with the opposite sex ( r =-0 25, P <0 05), positive influence in social activiies ( r =-0 22, P <0 05) Conclusion The psychological status before surgery and the outcome following orthognathic surgery in patients with skeletal Class Ⅲ malocclusion were closely related to severity of the malocclusion

关键词： Class Ⅲ malocclusion · psychological status · motivation · outcome

RECONSIDERATION OF THE urbanIZATION RESEARCH IN CHINA

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Chinese Geographical Science 2000年第2期10卷 119-124页

作者： ZHANG Jing-xiang(Department of urban and Resources Science, Nanjing University, Nanjng 210093, P R. China) Department of urban and Resources Science Nanjing University Nanjing P. R. China

By restudying some ideas existing in the current urbanization research field in China, this article truly puts forward the inquisitive opinion with respect to the urbanization progress, urban scale. spatial transfer of urbanization and suburbanization in China, etc. It indicates that the urbanization shall abide by the economic laws, but government should bring the appropriate adjustment and control into play as well; the urbanization shall not be limited to the west ern pattern and simple phenomenal analysis, but to pursue the virtually healthy, orderly and sustainable development of cities is the man aim for urbanization. The main views of this article are as follows: 1 ) As far as Chinese urbanization is concerned, it is in a different age compared with the west, and it has one special domestic background, so its speed and mode are different from the west and the speed can’ t be too fast. 2) External extending economic evelopment will still last for a Period. And the urbanization development has big spatial requirements. Therefore, intensive development mode of space should be explored. 3) The suburbanization in China has special forming mechanism and relevant social problems, which should be treated seriously.

关键词： urbanization suburbanization urban scale

中国城市创伤救治体系建设标准专家共识(2024年版)

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中华骨科杂志 2024年第1期44卷 1-5页

作者：中国城市创伤救治体系建设标准专家共识专家组姜保国王艳华黄伟晋菲斐中国城市创伤救治体系建设标准专家共识专家组

随着我国经济快速增长,道路交通和建筑行业持续发展,创伤发病率不断升高。为此,国家创伤医学中心及中国创伤救治联盟的专家团队根据中国国情提出在综合医院建立创伤救治团队替代独立的创伤救治中心及建立以综合医院为核心的闭环式区域... 详细信息

随着我国经济快速增长,道路交通和建筑行业持续发展,创伤发病率不断升高。为此,国家创伤医学中心及中国创伤救治联盟的专家团队根据中国国情提出在综合医院建立创伤救治团队替代独立的创伤救治中心及建立以综合医院为核心的闭环式区域性创伤救治体系。过去几年中,在国家卫生健康委的推动下这一体系在全国得到广泛推广。尤其是在县域内,以县内最好的综合医院为救治主体,整合县域内的院前急救及周边救治点使其形成有效的创伤救治体系。而城市创伤体系建设更加复杂,因此目前尚未形成相对统一的建设标准。为规范城市创伤救治体系的建设,提高创伤尤其是严重创伤救治的成功率,国家创伤医学中心组织专家就如何优化大型城市城区内创伤救治中心布局、提升创伤救治能力进行研讨,制订了《中国城市创伤救治体系建设标准专家共识(2024版)》,以期为我国城市城区创伤救治布局提供参考。

关键词：创伤和损伤医院,市区急救共识中国