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Chinese Journal of Aeronautics 1997年第3期10卷 2-8页

作者： zhang zhengke, zhu zhiqiang, zhuang fenggan (Institute of Fluid Mechanics, Beijing University of Aeronautics and Astronautics, Beijing, 100083, China)

A complete process of grid generation for complex practical aircraft is described with a twin tail fighter as an example. Euler equations are discretized in the generated multiblock grid by a finite volume method and solved by a three stage explicit time stepping scheme in each block with some extra treatments of interface at each step. The predicted aerodynamic coefficients and vortical flow field are reasonable.

关键词： fighter aircraft grid generation (mathematics) elliptic partial differential equations Euler equations zonal method

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Mn基低温脱硝催化剂性能优化研究进展

工程科学学报 2025年第1期47卷 142-157页

作者：许芸邬博宇庄柯张乾徐静馨张深根朱法华张柏林国家能源集团科学技术研究院有限公司低碳智能燃煤发电与超净排放全国重点实验室南京210023 北京科技大学新材料技术研究院北京100083

氮氧化物(NO_(x))是我国首要大气污染物,主要采用选择性催化还原(SCR)技术进行排放控制.研发高效、稳定的低温脱硝催化剂可避免高能耗的烟气再热,具有显著的节能降碳效益.锰氧化物(MnO_(x))因多变的化学态和丰富的晶格缺陷而表现出优良... 详细信息

氮氧化物(NO_(x))是我国首要大气污染物,主要采用选择性催化还原(SCR)技术进行排放控制.研发高效、稳定的低温脱硝催化剂可避免高能耗的烟气再热,具有显著的节能降碳效益.锰氧化物(MnO_(x))因多变的化学态和丰富的晶格缺陷而表现出优良的氧化还原性能,并具有极强的表面酸性,在催化还原NO_(x)反应中表现出良好的低温活性,但N_(2)选择性低、抗H_(2)O/SO_(2)性能差,难以实现长期的高效稳定脱硝.近年来,改性提升Mn基催化剂的研究十分广泛,加快了Mn基催化剂工业应用的步伐.本文从低温活性、N_(2)选择性和稳定性三个方面,总结了Mn基催化剂的脱硝反应机理、元素掺杂改性、催化剂结构设计等最新研究进展,指出了当前的研究重点和难点,可为下一步研究提供参考.

关键词：氮氧化物选择性催化还原锰基催化剂 N2选择性稳定性元素掺杂

Enhanced production of cytidine 5'-monophosphate using biocatalysis of di-enzymes immobilized on amino-functionalized sepharose

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Chinese Journal of Chemical Engineering 2023年第6期58卷 40-52页

作者： Xiaohong Zhou Wenfeng Zhou Wei zhuang Chenjie zhu Hanjie Ying Hongman zhang School of Chemistry and Molecular Engineering Nanjing Tech UniversityNanjing 211816China State Key Laboratory of Materials-Oriented Chemical Engineering College of Biotechnology and Pharmaceutical EngineeringNational Engineering Technique Research Center for BiotechnologyNanjing Tech UniversityNanjing 211816China

Cytidine 5'-monophosphate(5'-CMP)is an essential nucleotide for *** this study,enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes,uridine-cytidine kinase(UCK)and acetate kinase(AcK).The immobilization yield of the enzyme had a clear correlation with the surface charges as zeta potential(ξ).Among them,ε-polylysinefunctionalized sepharose(SA-EPL,ξ=9.31 m V)showed high immobilization yield(78.8%),which was4.9-fold than that of nitrilotriacetic acid functionalized sepharose(SA-NTA,ξ=-12.6 m V).The residual activity of affinity co-immobilized enzyme(EPL-Ni/EPL@Ac K-UCK)was higher than 70.6%after recycled 10 ***,this study provides an effective approach for the production of 5'-CMP with the advantages of low adenosine 5'-triphosphate(ATP)consumption,reduced side reactions,and improved reusability by co-immobilized UCK and Ac K on the functionalized Sepharose.

关键词： Sepharose ε-Polylysine Dual-enzyme cascade Cytidine 5'-monophosphate Enzyme immobilization

Experimental and Numerical Investigation of Impingement Heat Transfer on Target Plate with Streamlined Roughness Element at Maximum Crossflow Condition

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Journal of Thermal Science 2022年第3期31卷 751-764页

作者： WU zhuang zhu Huiren GAO Qiang LIU Cunliang LI Lin zhang Zheng School of Power and Energy Northwestern Polytechnical UniversityXi’an710071China Shaanxi Key Laboratory of Thermal Sciences in Aero-engine System Xi’an710071China

A combined experimental and numerical investigation of the heat transfer and flow characteristics of the roughened target plate has been *** the data are compared with the flat *** novel streamlined roughness elements are proposed:similar round protuberance,similar trapezoidal straight rib,and similar trapezoidal curved *** experiments are carried out in a perspex model using the transient thermochromic liquid crystal *** effect of jet Reynolds number,rib height,and rib shape on the Nusselt number and flow discharge coefficient has been *** ribs provide higher heat transfer *** curved ribs provide better heat transfer *** the experimental scope,combined straight rib plate and combined curved rib plate increase the area averaged Nusselt number by 11.5%and 13.8%*** experiment is complemented by a numerical part,which can provide flow field analysis and the Nusselt number on the surface of the small size roughness *** numerical results show the protuberance can shorten the nozzle to plate distance and make the shifting point move *** ribs have a guidance effect on crossflow and reduce the transverse interference to the downstream *** transferred heat flux caused by the side surface of the roughness element is very *** heat flux contributed by the side surface of the protuberance and ribs can reach 26%and 10%respectively.

关键词： impingement cooling roughness element heat transfer flow discharge coefficient

Experimental investigation of flow past a circular cylinder with hydrophobic coating

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Journal of Hydrodynamics 2018年第6期30卷 992-1000页

作者： Jun Wen Hai-bao Hu zhuang-zhu Luo Zhao-zhu zhang School of Marine Science and Technology Northwestern Polytechnical University Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical Physics Chinese Academy of Sciences

A series of experiments are performed in a gravitational low-speed water tunnel to investigate the influence of the hydrophobic coating on the flow past a circular cylinder. The mean velocity and turbulence intensity profiles behind the cylinders are measured using the hot-film anemometer while the separation angles are obtained with the flow visualization technology. For the Reynolds number lower than 3 800, the hydrophobic coatings are in the Cassie state, the velocity deficit and the turbulence intensity in the wake of the hydrophobic cylinders are lower than those of the smooth cylinders which implies the drag reduction effect of the hydrophobic coatings. When the Reynolds number becomes higher than 6 600, the hydrophobic coatings turn into the Wenzel state. Through decomposing the velocity data in the turbulent wake into different scales based on the orthogonal wavelet transform, it is found that the total turbulence intensity in the wake of the hydrophobic cylinders becomes almost the same as in the wake of the smooth cylinders while the intensity of the large scales of vortex components in the wake of the hydrophobic cylinders is still lower. Furthermore, the separation angles show the same trend as a function of the Reynolds number but always take smaller values for the hydrophobic cylinders.

关键词： Hydrophobic coating drag reduction vortex structures separated flows

Photoluminescence and surface photovoltage properties of Zn Se nanoribbons

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Science Bulletin 2015年第19期60卷 1674-1679页

作者： Chao Fan Qinglin zhang Xiaoli zhu Xiujuan zhuang Anlian Pan Key Laboratory for Micro Nano Physics and Technology of Hunan Province School of Physics and Electronic ScienceHunan University

ZnSe nanoribbons were synthesized with chemical vapor deposition route. The excitation power-dependent photol and surface photovoltage （SPV） techniques were used to study the optoelectronic properties of the as-grown ZnSe nanoribbons. Three deep defect （DD）-related emission bands, respectively, centered at 623 nm （DD1）, 563 nm （DD2） and 525 nm （DD3）, emerge orderly with increasing the excitation power, which is attributed to the saturation of the DD states from deeper to shallower level. The SPV spectrum and the corresponding phase spectrum show that DD1 mainly acts as recombination center, while DD2 and DD3 can act as both the recombination center and electron traps. The influence of the trapping electrons on the SPV response dynamic was studied with transient SPV.

关键词： ZnSe Nanoribbon Photoluminescence Surface photovoltage Deep defect

Insights into Convective-scale Predictability in East China: Error Growth Dynamics and Associated Impact on Precipitation of Warm-Season Convective Events

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Advances in Atmospheric Sciences 2020年第8期37卷 893-911页

作者： Xiaoran zhuang Jinzhong MIN Liu zhang Shizhang WANG Naigeng WU Haonan zhu Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Key Laboratory of Meteorological Disaster of EducationNanjing University of Information Science and TechnologyNanjing 210044China Jiangsu Meteorological Observatory Jiangsu Meteorological BureauNanjing 210008China Key Laboratory of Regional Numerical Weather Prediction Institute of Tropical and Marine MeteorologyChina Meteorological AdministrationGuangzhou 210044China Chongqing Climate Center Chongqing Meteorological BureauChongqing 401120China

This study investigated the regime-dependent predictability using convective-scale ensemble forecasts initialized with different initial condition perturbations in the Yangtze and Huai River basin(YHRB)of East *** scale-dependent error growth(ensemble variability)and associated impact on precipitation forecasts(precipitation uncertainties)were quantitatively explored for 13 warm-season convective events that were categorized in terms of strong forcing and weak *** forecast error growth in the strong-forcing regime shows a stepwise increase with increasing spatial scale,while the error growth shows a larger temporal variability with an afternoon peak appearing at smaller scales under weak *** leads to the dissimilarity of precipitation uncertainty and shows a strong correlation between error growth and precipitation across spatial *** lateral boundary condition errors exert a quasi-linear increase on error growth with time at the larger scale,suggesting that the large-scale flow could govern the magnitude of error growth and associated precipitation uncertainties,especially for the strong-forcing *** comparisons between scale-based initial error sensitivity experiments show evident scale interaction including upscale transfer of small-scale errors and downscale cascade of larger-scale ***,small-scale errors are found to be more sensitive in the weak-forcing regime than those under strong ***,larger-scale initial errors are responsible for the error growth after 4 h and produce the precipitation uncertainties at the meso-β-***,these results can be used to explain underdispersion issues in convective-scale ensemble forecasts and provide feedback for ensemble design over the YHRB.

关键词： convective-scale predictability error growth strong forcing weak forcing scale interaction

Combat data shift in few-shot learning with knowledge graph

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Frontiers of Computer Science 2023年第1期17卷 101-111页

作者： Yongchun zhu Fuzhen zhuang Xiangliang zhang Zhiyuan QI Zhiping SHI Juan CAO Qing HE Key Lab of Intelligent Information Processing of Chinese Academy of Sciences(CAS) Institute of Computing TechnologyCASBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Institute of Artificial Intelligence Beihang UniversityBeijing 100191China Xiamen Institute of Data Intelligence Xiamen 361021China Computer Science and Engineering University of Notre DameIN 46556USA University of California San Diego La JollaCA 92093USA College of Information Engineering&Academy for Multidisciplinary Studies Capital Normal UniversityBeijing 100089China

Many few-shot learning approaches have been designed under the meta-learning framework, which learns from a variety of learning tasks and generalizes to new tasks. These meta-learning approaches achieve the expected performance in the scenario where all samples are drawn from the same distributions (i.i.d. observations). However, in real-world applications, few-shot learning paradigm often suffers from data shift, i.e., samples in different tasks, even in the same task, could be drawn from various data distributions. Most existing few-shot learning approaches are not designed with the consideration of data shift, and thus show downgraded performance when data distribution shifts. However, it is non-trivial to address the data shift problem in few-shot learning, due to the limited number of labeled samples in each task. Targeting at addressing this problem, we propose a novel metric-based meta-learning framework to extract task-specific representations and task-shared representations with the help of knowledge graph. The data shift within/between tasks can thus be combated by the combination of task-shared and task-specific representations. The proposed model is evaluated on popular benchmarks and two constructed new challenging datasets. The evaluation results demonstrate its remarkable performance.

关键词： few-shot data shift knowledge graph

Scientific design and preliminary results of three-dimensional variational data assimilation system of GRAPES

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Chinese Science Bulletin 2008年第22期53卷 3446-3457页

作者： XUE JiShan zhuang ShiYu zhu GuoFu zhang Hua LIU ZhiQuan LIU Yan zhuang ZhaoRong State Key Laboratory for Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081 China National Meteorological Center China Meteorological Administration Beijing 100081 China National Satellite Meteorological Center China Meteorological Administration Beijing 100081 China

The scientific design and preliminary results of the data assimilation component of the Global-Regional Prediction and Assimilation System (GRAPES) recently developed in China Meteorological Administration (CMA) are presented in this paper. This is a three-dimensional variational (3DVar) assimilation system set up on global and regional grid meshes favorable for direct assimilation of the space-based remote sensing data and matching the frame work of the prediction model GRAPES. The state variables are assumed to decompose balanced and unbalanced components. By introducing a simple transformation from the state variables to the control variables with a recursive or spectral filter, the convergence rate of iteration for minimization of the cost function in 3DVar is greatly accelerated. The definition of dynamical balance depends on the characteristic scale of the circulation considered. The ratio of the balanced to the unbalanced parts is controlled by the prescribed statistics of background errors. Idealized trials produce the same results as the analytic solution. The results of real data case studies show the capability of the system to improve analysis compared to the traditional schemes. Finally, further development of the system is discussed.

关键词：数值天气预报气象学天气预测气象分析

Prevalence of physical fitness in Chinese school-aged children： Findings from the 2016 Physical Activity and Fitness in China -The Youth Study

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Journal of Sport and Health Science 2017年第4期6卷 395-403页

作者： Zheng zhu Yang Yang Zhenxing Kong Yimin zhang Jie zhuang Shanghai Research Center for Physical Fitness and Health of Children and Adolescents Shanghai University of Sport Shanghai 200438 China School of Kinesiology Shanghai University of Sport Shanghai 200438 China Shanghai Municipal Center for Students' Physical Fitness and Health Surveillance Shanghai Municipal Education Committee Shanghai 200011 China Key Laboratory of Exercise and Physical Fitness Ministry of Education Beijing Sport University Beijing 100084 China

Purpose： This study was to present the 2016 prevalence estimates of Chinese school-aged children meeting physical fitness standards and to examine differences by sex and residence locales in children who did not meet fitness standards. Methods： We conducted cross-sectional analyses of 171,991 children and adolescents （boy： 50.0%, Grades 1-12） who participated in the 2016 Physical Activity and Fitness in China--The Youth Study. The main outcomes were fitness measures, assessed by the 2014 revised Chinese National Student Physical Fitness Standard （CNSPFS）, covering areas of aerobic capacity, upper body strength, flexibility, body mass index, abdominal strength, and trunk strength. Children＇s overall physical fitness performance was categorized, per CNSPFS standards, as excellent, good, pass, or no pass. Data on the prevalence of physical fitness categories and not meeting fitness standards （i.e., among children who received a ＂no pass＂ mark） were analyzed, through logistic regression, by sex （boy, girl） and residence locales （urban, rural） across 3 school grades （primary, junior middle, and junior high）. Results： In 2016, 5.95% of Chinese children and adolescents achieved an ＂excellent＂ mark, 25.80% received a ＂good＂ rating, 59.90% received a ＂pass＂, and 8.35% received a ＂no pass＂. Overall, boys were more likely to not pass the fitness standards compared with girls （adjusted odds ratio （aOR） = 1.710; 95% confidence interval （CI）： 1.708-1.712） and children living in urban areas were more likely to not pass the standards than those living in rural areas （aOR = 1.298; 95%CI： 1.296-1.299）. Consistent patterns of not meeting fitness standards were also found by sex and residence locales across all 3 school grades. Conclusion： In the Chinese school-aged population, about 3 in 10 children achieved an ＂excellent＂ or ＂good＂ fitness standard in 2016, and about 8% of this population did not meet CNSPFS standards. Children living in urban areas were more likely to not meet minim

关键词： Cardiorespiratory endurance Children Fimess Flexibility Muscular strength Physical activity