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基于霍克-布朗准则的深埋隧道塌方机制泛函突变分析(英文)

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2014年第9期15卷 723-731页

作者： cheng-ping zhang Kai-hang HAN Qian FANG Ding-li zhang MOE Key Lab of Urban Underground Engineering Beijing Jiaotong University School of Civil Engineering Beijing Jiaotong University

研究目的:分析深埋隧道的塌方机制并推导塌方体形状曲线的解析表达式。创新要点:基于霍克-布朗准则,采用泛函突变理论推导得到了深埋隧道塌方体形状曲线的解析表达式,并据此分析了围岩参数变化对塌方体形状的影响规律。研究方法:通过理... 详细信息

研究目的:分析深埋隧道的塌方机制并推导塌方体形状曲线的解析表达式。创新要点:基于霍克-布朗准则,采用泛函突变理论推导得到了深埋隧道塌方体形状曲线的解析表达式,并据此分析了围岩参数变化对塌方体形状的影响规律。研究方法:通过理论分析建立深埋圆形隧道的解析模型(图1),采用泛函突变理论推导基于霍克-布朗准则的隧道塌方体形状曲线解析表达式,并研究围岩参数变化对塌方体形状的影响规律(图3和4,表2)。通过与自然拱理论和模型试验结果的对比(图5–7)验证本文解析解的正确性。重要结论:采用泛函突变理论推导了基于霍克-布朗准则的深埋隧道塌方体形状曲线解析表达式。该解析表达式简洁直观,不仅可以预测无支护条件下隧道的塌落体尺寸,还可以估算塌落围岩作用于衬砌上的荷载。

关键词：深埋隧道隧道塌方泛函突变理论霍克-布朗准则

SYNTHESIS AND TAUTOMERISM OF KETENE N,O-ACETALS WITH BENZOXAZOLINE RING

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Chinese Chemical Letters 1990年第2期1卷 167-170页

作者： Zhi Tang HUANG ping cheng zhang Institute of Chemistry,Academia Sinica,Beijing,100080

Benzoxazoline ring substituted ketene N,O-acetals 3 were synthesized by the reaction of ketene S,S-acetals 2 with *** tautomeric equilibrium of some 3 was also observed.

关键词： ppm cm MS SYNTHESIS AND TAUTOMERISM OF KETENE N,O-ACETALS WITH BENZOXAZOLINE RING NH UV

Total Synthesis of (±)-Nimbonone and (±)-12-Ethyl-13-methoxy- 8,11,13-podocarpatriene

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Chinese Chemical Letters 2002年第10期13卷 935-936页

作者： cheng Lu zhang, ping Yan BIE, Xuan Jia PENG, Xin Fu PAN* Department of Chemistry, National Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000 Department of Chemistry National Laboratory of Applied Organic Chemistry Lanzhou University

A facile total synthetic route to (±)-nimbonone and (±)-12-ethyl-13-methoxy- 8,11,13-podocarpatriene was developed. The Wittig reaction of cyclocitral with (3-methoxy- benzyl) triphenylphosphonium and intramolecular cyclization with BF3Et2O in the synthetic progress were applied. In order to induce the ethyl substituent, Fiedel-Crafts acetylation and then decarbonylation had been employed.

关键词： Total synthesis (±)-nimbonone diterpene.

Microvascular free flaps in oral and maxinofacial reconstruction： a report on 138 cases

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中国口腔颌面外科杂志 2008年第B5期6卷 96-97页

作者： Zheng Xue Han cheng ping zhang Department of Oral & Maxillofacial Surgery Beijing Stomatological Hospital Capital Medical University. Beijing 100050 Department of Oral & Maxillofacial Surgeo Ninth People's Hospital College of Stomatology School of Medicine Shanghai Jiao Tong University Shanghai 200011 China

Control of Corner Separation for a Linear Compressor Cascade via Bionic Slanting Riblets at the Endwall

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Journal of Thermal Science 2025年第1期34卷 129-144页

作者： zhang Peng LI Yonghong cheng Rixin Key Laboratory of Civil Aircraft Airworthiness Technology Civil Aviation University of ChinaTianjin 300300China College of Aeronautical Engineering Civil Aviation University of ChinaTianjin 300300China

A new passive control approach,utilizing bionic slanting riblets,is employed to mitigate the flow close to the blade endwall in a linear cascade,and its effectiveness and mechanism in controlling corner separation are investigated through numerical *** slanting riblets are positioned at the endwall upstream of the cascade channel,and the influence of riblet height,yaw angle and relative position on the control of corner separation is *** findings indicate that the application of slanting riblets can efficiently counteract corner separation across the stable operational ***,the introduction of riblets with a height of merely 0.1 times the boundary layer thickness results in a significant reduction in total pressure loss by up to 14.53%,while simultaneously enhancing the static pressure coefficient by 21.74%.Flow analysis reveals that minute vortices produced within the riblet channels tend to coalesce,forming a potent large-scale vortex near the boundary layer's base *** phenomenon results in reduced additional losses compared to conventional vortex ***,the induced vortex promotes enhanced mixing between the mainstream flow and boundary layer,inhibiting the lateral displacement of low-energy fluids within the endwall boundary ***,this delays the onset of separation vortex formation and eliminates vortex rings in the corner region,ultimately enhancing the aerodynamic efficiency of the cascade.

关键词： corner separation compressor cascade slanting riblets additional losses vortex generator

Reversible Li plating regulation on graphite anode through a barium sulfate nanofibers-based dielectric separator for fast charging and high-safety lithium-ion battery

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Journal of Energy Chemistry 2025年第2期101卷 511-523页

作者： Yaxin zhang Long cheng Ying-Jie Zhu Jin Wu Han-ping Yu Sida Xie Dandan Li Zhaohui Wang Heng Li State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences College of Materials Science and Engineering Hunan University Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences

Poor Li plating reversibility and high thermal runaway risks are key challenges for fast charging lithiumion batteries with graphite ***,a dielectric and fire-resistant separator based on hybrid nanofibers of barium sulfate（BS） and bacterial cellulose（BC） is developed to synchronously enhance the battery's fast charging and thermal-safety *** regulation mechanism of the dielectric BS/BC separator in enhancing the Li+ion transport and Li plating reversibility is revealed.（1） The Max-Wagner polarization electric field of the dielectric BS/BC separator can accelerate the desolvation of solvated Li+ions,enhancing their transport kinetics.（2） Moreover,due to the charge balancing effect,the dielectric BS/BC separator homogenizes the electric field/Li+ion flux at the graphite anode-separator interface,facilitating uniform Li plating and suppressing Li dendrite ***,the fast-charge graphite anode with the BS/BC separator shows higher Coulombic efficiency（99.0% vs.96.9%） and longer cycling lifespan（100 cycles vs.59 cycles） than that with the polypropylene（PP） separator in the constantlithiation cycling test at 2 mA *** high-loading LiFePO4(15.5 mg cm-2)//graphite(7.5 mg cm-2) full cell with the BS/BC separator exhibits excellent fast charging performance,retaining 70% of its capacity after 500 cycles at a high rate of 2C,which is significantly better than that of the cell with the PP separator（retaining only 27% of its capacity after 500 cycles）.More importantly,the thermally stable BS/BC separator effectively elevates the critical temperature and reduces the heat release rate during thermal runaway,thereby significantly enhancing the battery's safety.

关键词： Fast charging Graphite anode Ion transport Lithium-ion battery Separator

Molecular dynamics simulations of helium transport through inorganic mineral nanopores

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Science China Earth Sciences 2025年第1期68卷 237-252页

作者： Dandan SONG ping GUAN Chi zhang Jiahao REN School of Earth and Space Sciences Peking UniversityBeijing100871China

Helium transport through nanoscale inorganic mineral pores and pore throats is essential for its overall *** elucidate helium's transport dynamics within nanopores,we employed equilibrium and non-equilibrium molecular dynamics simulations to investigate helium's static self-diffusion and pressure-driven flow in quartz slit-shaped *** also introduced water and various gases,including hydrogen,methane,ethane,nitrogen,and carbon dioxide,into the nanopores to assess their influence on helium *** findings indicate minimal helium adsorption on quartz pore *** conditions where the pore size is less than 5 nm and the pressure under 10 MPa,environmental factors markedly influence helium *** pore sizes,high temperatures,and low gas pressures enhance helium desorption and facilitate faster *** observed a positive correlation between helium flow velocity and factors such as pore size,pressure gradient,and surface smoothness of the ***,the presence of pore water and carrier gases in quartz nanopores,which diffuse more slowly than helium,tends to reduce helium surface adsorption and slow its *** the carrier gases studied,nitrogen showed similar adsorption capacity,diffusivity,and stability to helium,while carbon dioxide displayed the highest adsorption capacity and the slowest diffusion rate,markedly differing from *** on the simulation results,we concluded that water and carrier gases primarily function as transport mediums in helium migration,moving together with ***,which shares similar properties with helium,effectively assists in this co-migration ***,carbon dioxide,due to its high adsorption capacity and slow diffusion,tends to be lost during *** a result,gas reservoirs with high nitrogen levels and low carbon dioxide levels are more likely to have higher helium ***,the smaller pore sizes and higher gas pressures in caproc

关键词： Helium transport Slit nanopores Molecular dynamics simulations Diffusion Flow carriers

A Machine Learning-Based Observational Constraint Correction Method for Seasonal Precipitation Prediction

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Advances in Atmospheric Sciences 2025年第1期42卷 36-52页

作者： Bofei zhang Haipeng YU Zeyong HU ping YUE Zunye TANG Hongyu LUO Guantian WANG Shanling cheng Key Laboratory of Cryospheric Science and Frozen Soil Engineering Nagqu Plateau Climate and Environment Observation and Research Station of Tibet Autonomous RegionNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of the Chinese Academy of Sciences Beijing 100049China Key Open Laboratory of Arid Climate Change and Disaster Reduction of CMA Key Laboratory of Arid Climate Change and Reducing Disaster of Gansu ProvinceInstitute of Arid MeteorologyChina Meteorological AdministrationLanzhou 730000China School of Computer Science and Technology Faculty of Electronic and Information EngineeringXi’an Jiaotong UniversityXi’an 710049China

Seasonal precipitation has always been a key focus of climate *** a dynamic-statistical combined method,the existing observational constraint correction establishes a regression relationship between the numerical model outputs and historical observations,which can partly predict seasonal ***,solving a nonlinear problem through linear regression is significantly *** study implements a nonlinear optimization of an existing observational constrained correction model using a Light Gradient Boosting Machine(LightGBM)machine learning algorithm based on output from the Beijing National Climate Center Climate System Model(BCC-CSM)and station observations to improve the prediction of summer precipitation in *** model was trained using a rolling approach,and LightGBM outperformed Linear Regression(LR),Extreme Gradient Boosting(XGBoost),and Categorical Boosting(CatBoost).Using parameter tuning to optimize the machine learning model and predict future summer precipitation using eight different predictors in BCC-CSM,the mean Anomaly Correlation Coefficient(ACC)score in the 2019–22 summer precipitation predictions was 0.17,and the mean Prediction Score(PS)reached *** PS score was improved by 7.87%and 6.63%compared with the BCC-CSM and the linear observational constraint approach,*** observational constraint correction prediction strategy with LightGBM significantly and stably improved the prediction of summer precipitation in China compared to the previous linear observational constraint solution,providing a reference for flood control and drought relief during the flood season(summer)in China.

关键词： observational constraint LightGBM seasonal prediction summer precipitation machine learning

Lessons from Nature:Advances and Perspectives in Bionic Microwave Absorption Materials

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Nano-Micro Letters 2025年第4期17卷 454-486页

作者： Dashuang Wang Tuo ping Zhilan Du Xiaoying Liu Yuxin zhang College of Materials Science and Engineering Chongqing UniversityChongqing 400044People’s Republic of China Army Logistics Academy of PLA Chongqing 401331People’s Republic of China Beijing Spacecrafts China Academy of Space TechnologyBeijing 100194People’s Republic of China

Inspired by the remarkable electromagnetic response capabilities of the complex morphologies and subtle microstructures evolved by natural organisms,this paper delves into the research advancements and future application potential of bionic microwave-absorbing materials(BMAMs).It outlines the significance of achieving high-performance microwave-absorbing materials through ingenious microstructural design and judicious composition selection,while emphasizing the innovative strategies offered by bionic ***,this work meticulously analyzes how inspiration can be drawn from the intricate structures of marine organisms,plants,animals,and nonmetallic minerals in nature to devise and develop BMAMs with superior electromagnetic wave absorption ***,the paper provides an in-depth exploration of the theoretical underpinnings of BMAMs,particularly the latest breakthroughs in broadband *** incorporating advanced methodologies such as simulation modeling and bionic gradient design,we unravel the scientific principles governing the microwave absorption mechanisms of BMAMs,thereby furnishing a solid theoretical foundation for understanding and optimizing their ***,this review aims to offer valuable insights and inspiration to researchers in related fields,fostering the collective advancement of research on BMAMs.

关键词： Bionic Structural design Microwave absorption Electromagnetic theory