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Unsteady aerodynamic noise prediction of contra-rotating open rotor using meshless method

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Chinese Journal of Aeronautics 2024年第8期37卷 144-165页

作者： Zhiliang HONG Meng SU haitao ZHANG Zerui XU Lin du Lingfeng CHEN College of Safety Science and Engineering Civil Aviation University of ChinaTianjin 300300China Civil Aviation Administration of China Beijing 100710China Research Institute of Aero-Engine Beihang UniversityBeijing 100191China

The Contra-Rotating Open Rotor(CROR)design confronts significant noise challenges despite being one of the possible options for future green *** efficiently estimate the noise emitted from a CROR,a three-dimensional unsteady prediction model based on the meshless method is *** unsteady wake flow and the aerodynamic load fluctuations on the blade are solved through the viscous vortex particle method,the blade element momentum theory and vortex lattice ***,the acoustic field is obtained through the Farassat’s formulation *** of this method is conducted on a CROR,and a mesh-based method,e.g.,Nonlinear Harmonic(NLH)method,is also employed for *** is found that the presented method is three times faster than NLH method while maintaining a comparable precision.A thorough parametric analysis is also carried out to illustrate the effects of rotational speed,rotor-rotor spacing and rear rotor diameter on the noise *** rotor speed is found to be the most influencing factor,and by optimizing the speed difference between the front and rear rotors,a notable noise reduction can be *** current findings not only contribute to a deeper comprehension of the CROR’s aeroacoustic properties but also offer an effective tool for engineering applications.

关键词： Contra-Rotating Open Rotor(CROR) Aerodynamic noise Blade element momentum theory Viscosity vortex particle method Farassat’s formulation 1A

Carbon-coated MoS_(2) nanosheets@CNTs-Ti_(3)C_(2) MXene quaternary composite with the superior rate performance for sodium-ion batteries

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Journal of Materials Science & Technology 2022年第5期100卷 101-109页

作者： Fengyi He Cheng Tang Yadong Liu haitao Li Aijun du Haijiao Zhang Institute of Nanochemistry and Nanobiology Shanghai UniversityShanghai 200444China School of Chemistry Physics and Mechanical EngineeringScience and Engineering FacultyQueensland University of TechnologyBrisbaneQLD 4001Australia

The exploration of advanced MoS_(2)-based electrode materials overcoming their inherent low conductivity and large volume changes is of importance for next-generation energy *** this work,we report a simple and high-efficient one-pot hydrothermal approach to prepare a unique and stable 1D/2D *** the architecture,ultrathin carbon layer-coated MoS_(2) nanosheets with large expanded interlayer of 1.02 nm are vertically grown onto the Ti_(3)C_(2) MXene and cross-linked carbon nanotubes(CNTs),giving rise to a highly conductive 3D *** interlayer expanded MoS_(2) nanosheets can greatly facilitate the Na ions/electrons ***,the N-doped 1D/2D CNTs-Ti_(3)C_(2) matrix can be used as a strong mechanical support to well relieve the large volume expansion upon *** a combination result of several advantages,the developed quaternary C-MoS_(2)/CNTs-Ti_(3)C_(2) composite anode shows an excellent sodium storage performance(562 mA h g^(-1) at 100 mA g^(-1) after 200 cycles)and rate capability(475 mA h g^(-1) at 2000 mA g^(-1)).The density functional theory calculations further prove that the full combination of layer-expanded MoS_(2) nanosheets and N-doped Ti_(3)C_(2) matrix can significantly enhance the adsorption energy of Na ions,further resulting in the enhancement of sodium storage capabilities.

关键词： MoS_(2)nanosheets Ti_(3)C_(2)MXene Quaternary composite Nitrogen doping Sodium-ion batteries

Microstructure and Mechanical Properties of Nickel‑Aluminum Bronze Coating on 17‑4PH Stainless Steel by Laser Cladding

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Chinese Journal of Mechanical Engineering 2022年第6期35卷 403-414页

作者： Lu Zhao Baorui du Jun Yao haitao Chen Ruochen Ding Kailun Li Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Shenyang Dalu Laser Advanced Manufacturing Technology Innovation Co.Ltd Shenyang 110000China Institute of Science and Technology China Three Gorges CorporationBeijing 100038China

Bimetallic copper-steel composite could be an effective structural material to improve the performance of traditional nickel-aluminum bronze(NAB)ship propeller due to its high structural strength and corrosion *** this work,the defect-free NAB coatings has been successfully fabricated by laser direct depositing technique on the 17-4PH stainless steel *** phase constitution,microstructure characteristics and hardness properties were investigated in *** XRD results showed that the coatings mainly consisted ofα-Cu,Fe and intermetallicκphases despite the diffraction peaks shifted more than 0.5°,which may due to the influence of the Ni,Fe and Al atoms dissolved into *** microstructures of the coatings were affected significantly by laser energy density according to SEM and EDS *** top region of the coating was more undercooled during solidification,therefore the grains at this region was much finer than that at the bottom *** higher energy input would lead to coarser ***-rich dendrites and spherical particles were found in the Cu matrix,which could be a result of liquid *** hardness of the coating is in the range of 204 HV0.2–266 HV0.2 which is higher than traditional as-cast *** uneven distribution of Fe-rich phases as well as the hardκphases could be the main reasons for the fluctuations of the hardness *** fracture occurred at bronze side,not at transition zone,which shows there is a good interfacial bonding between the two metals produced by laser cladding.

关键词： Laser direct depositing Nickel-aluminum bronze Microstructure Hardness Tensile Liquid separation

普达措国家公园2个针叶树种径向生长对温度和降水的响应

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生态学报 2018年第15期38卷 5383-5392页

作者：张贇尹定财张卫国岳海涛杜杰次丹李秋平杨荣田昆西南林业大学国家高原湿地研究中心昆明650000 云南碧塔海省级自然保护区管理局丽江674400

基于树轮年代学方法,利用普达措国家公园海拔上、下限丽江云杉(Picea likiangensis)和长苞冷杉(Abies georgei)树轮宽度资料,构建差值年表并分析其与温度和降水的关系,阐明影响该区域2个主要针叶树种径向生长的主要气候要素。结果表明:... 详细信息

基于树轮年代学方法,利用普达措国家公园海拔上、下限丽江云杉(Picea likiangensis)和长苞冷杉(Abies georgei)树轮宽度资料,构建差值年表并分析其与温度和降水的关系,阐明影响该区域2个主要针叶树种径向生长的主要气候要素。结果表明:(1)海拔下限丽江云杉径向生长同时受到温度和降水的影响:与上年11月平均温、当年生长季后期(9—10月)平均温和上年7月降水呈显著正相关;(2)海拔上限丽江云杉径向生长只受温度影响,与上年生长季后期平均温呈显著负相关,与当年生长季盛期(6—8月)平均温呈显著正相关;(3)长苞冷杉径向生长只与温度表现出显著相关性,海拔下限的生长与上年11月平均温呈显著正相关,海拔上限的生长与当年生长季盛期平均温呈显著正相关。结果可为气候变化对滇西北高原树木生长影响研究提供参考,为滇西北高原森林生态系统管理与保护提供理论依据。

关键词：树木年轮海拔分布上限海拔分布下限丽江云杉长苞冷杉气候响应

A Self-Adaptive Back-off Optimization Scheme Based on Beacons Probability Prediction for Vehicle Ad-Hoc Networks

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China Communications 2016年第12期13卷 132-138页

作者： haitao Zhao Aiqian du Hongbo Zhu Dapeng Li Nanjie Liu College of Communication and Information Engineering Nanjing University of Posts and Telecommunications

In order to improve the broadcast reception rates of beacon messages in vehicle ad-hoc networks,a conclusion that the relationship between collision probability and minimum contention window size and the relationship between expiration probability and minimum window size was reached by building a Markov model. According to this conclusion, a back-off algorithm based on adjusting the size of minimum contention window called CEB is proposed, and this algorithm is on the basis of the differential size between the number of expiration beacons and preset threshold. Simulations were done to compare the performance of CEB with that of RBEB and BEB, and the results show that the performance of the new proposed algorithm is better than that of RBEB and BEB.

关键词： vehicle ad-hoc networks back off beacon expiration probability collision probability

Novel hybrid method to predict the ground-displacement field caused by shallow tunnel excavation

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Science China(Technological Sciences) 2023年第1期66卷 101-114页

作者： KONG FanChao LU DeChun MA YiDing TIAN Tao YU haitao du XiuLi Institute of Geotechnical and Underground Engineering Bejing University of TechnologyBejing 100124China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China

Based on machine-learning(ML) and analytical methods, a hybrid method is developed herein to predict the ground-displacement field(GDF) caused by tunneling. The extreme learning machine(ELM), as a single hidden layer feedforward neural network, is used as an ML model to predict maximum settlement smaxof the ground surface. The particle swarm optimization(PSO) algorithm is applied to optimize the parameters for the ELM method, namely, weight and bias values from the input layer to the hidden layer. The mean square error of the k-fold cross validation sets is considered the fitness function of the PSO algorithm. For 38 data samples from published papers, 30 samples are used as the training set, and 8 samples are used as the test set. For the test samples, the error of five samples ranges between-5 and 5 mm. The error of only one sample is slightly greater than 10 mm. The proposed PSO-ELM method demonstrates good prediction performance of smax. A deformation parameter of the nonuniform displacement mode for the tunnel cross-section is calibrated based on predicted smax. When the determined nonuniform displacement mode is used as the boundary condition of the tunnel cross-section, the GDF of a shallow circular tunnel is analytically predicted based on the complex-variable method prior to tunnel excavation. For a specific engineering case,i.e., the Heathrow Express tunnel, the proposed PSO-ELM-analytical method can well predict the surface-settlement trough curve, horizontal displacements at different depths, and vertical displacements above the tunnel.

关键词： extreme learning machine particle swarm optimization complex-variable method analytical solution of a shallow tunnel prediction method of ground-displacement field

浑水入渗对粗粒土柱孔隙及渗透性影响试验研究

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岩土工程学报 2025年第1期47卷 173-183页

作者：毛海涛张超袁古城何涛谷易山西农业大学城乡建设学院山西太原030000 重庆三峡学院土木工程学院重庆404120

浑水渗流在水利工程的反滤设计、浑水浇灌、堤坝渗流控制等方面都有较大影响,目前理论多采用稳定渗流计算方法,忽略了渗流过程中粗细颗粒与水力的耦合作用。自制渗流装置,将不同控制粒径浑水、不均匀系数粗粒土柱和水头等作为基本控制因... 详细信息

浑水渗流在水利工程的反滤设计、浑水浇灌、堤坝渗流控制等方面都有较大影响,目前理论多采用稳定渗流计算方法,忽略了渗流过程中粗细颗粒与水力的耦合作用。自制渗流装置,将不同控制粒径浑水、不均匀系数粗粒土柱和水头等作为基本控制因素,研究不同工况下浑水中悬浮颗粒对粗粒土土柱中的渗透特性影响;推导了变渗透系数浑水渗流计算微分方程,通过对比验证和公式修正,结果表明:粗粒土中颗粒淤积率与控制粒径C_(0.075)含量符合Boltzmann函数关系;C_(0.075)是重要的影响因子,浑水颗粒在粗粒土柱的运移、沉积和淤堵形态过程大致可分为4种形态:表层堆积淤堵形态(S型);表层-内部双重淤堵形态(S-I型);内部孔隙淤堵形态(I型);暂态孔隙淤堵形态(P型)。土柱C_(u)越大,孔隙度越小,浑水颗粒在粗粒土中运移也越困难,土柱填充性就越差;水头加剧了颗粒在土柱内部运移的速度,但也加速了其在顶部的沉积并封堵;S型时土柱0~2cm渗透系数下降速率最大,封堵时总体渗透系数最小,2cm以下相对孔隙率及随深度逐渐减小;S-I和I型土柱下部渗透系数明显滞后于上部,相对孔隙率存在临界深度(约为4~6cm);P型时土柱整体相对孔隙率基本无变化。

关键词：颗粒渗流粗粒土浑水堵塞

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核心蛋白聚糖的生物学功能概述

医学综述 2023年第20期29卷 4044-4050页

作者：赵慧强韩巧君易静杜海涛王华欧敏解放军总医院第二医学中心保健六科国家老年疾病临床医学研究中心北京100048 军事科学院军事医学研究院辐射医学研究所北京100850

核心蛋白聚糖(Decorin)是富含亮氨酸的小分子蛋白聚糖家族成员之一,主要存在于基质和上皮细胞中,在细胞外基质的组装中发挥重要作用,它可以广泛与各种分子结合并发挥生物学作用。目前,Decorin的生物学功能研究主要集中在抗纤维化、调节... 详细信息

核心蛋白聚糖(Decorin)是富含亮氨酸的小分子蛋白聚糖家族成员之一,主要存在于基质和上皮细胞中,在细胞外基质的组装中发挥重要作用,它可以广泛与各种分子结合并发挥生物学作用。目前,Decorin的生物学功能研究主要集中在抗纤维化、调节血管生成、抗肿瘤3个方面。近年来,Decorin的研究进展迅速,其作用机制得到全面阐述。在Decorin的众多作用机制中,抗肿瘤作用尤为重要,其中转化生长因子-β(TGF-β)信号通路在肿瘤的发生、发展中起重要作用,Decorin可以抑制TGF-β信号通路,从而为肿瘤生物治疗提供新的思路和方向,有着良好的临床应用前景。

关键词：核心蛋白聚糖生物学功能抗纤维化血管生成调节抗肿瘤

基于“肺与大肠相表里”理论的清热药抗RSV作用机制探讨

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世界科学技术-中医药现代化 2022年第10期24卷 3659-3666页

作者：景田园王平杜海涛孙铁锋李娜胡亚楠周倩张会敏王晓雪山东中医药大学药学院济南250355 山东省中医药研究院济南250014 天津大学精密测试技术及仪器国家重点实验室天津300072

呼吸道合胞病毒(RSV)是引起婴幼儿下呼吸道感染最常见的病原体之一,到目前尚无有效疫苗和特效药进行防治。清热药抗RSV作用显著,在临床已广泛应用,但其具体机制尚不明确。本文从中医理论角度,探讨“肺与大肠相表里”理论与RSV感染之间... 详细信息

呼吸道合胞病毒(RSV)是引起婴幼儿下呼吸道感染最常见的病原体之一,到目前尚无有效疫苗和特效药进行防治。清热药抗RSV作用显著,在临床已广泛应用,但其具体机制尚不明确。本文从中医理论角度,探讨“肺与大肠相表里”理论与RSV感染之间的关系,分析肠道菌群及黏膜免疫可能参与疾病的发生及防治,综述了清热药可能通过调节肠道菌群及黏膜免疫起到抗RSV作用,揭示肠道菌群及黏膜免疫可能成为抗RSV的新方向,为防控病毒感染性疾病以及开发高效抗病毒中药提供参考与依据,具有十分重要的理论及临床价值。

关键词：肺与大肠相表里呼吸道合胞病毒清热药肠道菌群黏膜免疫