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谷神星一号运载火箭的时变模态参数辨识

振动工程学报 2024年第5期37卷 729-736页

作者：马志赛丁千刘百奇刘建设张军锋董威利天津大学机械工程学院天津300350 天津市非线性动力学与控制重点实验室天津300350 北京星河动力装备科技有限公司北京100176

针对运载火箭这一大型复杂系统,单纯依靠机理分析难以建立能够精确描述其时变特征的动力学模型,借助模态辨识技术获取其在飞行状态下的时变动力学特性尤为必要。面向运载火箭的飞行模态辨识需求,发展基于时变自回归滑动平均模型的仅输... 详细信息

针对运载火箭这一大型复杂系统,单纯依靠机理分析难以建立能够精确描述其时变特征的动力学模型,借助模态辨识技术获取其在飞行状态下的时变动力学特性尤为必要。面向运载火箭的飞行模态辨识需求,发展基于时变自回归滑动平均模型的仅输出递推辨识方法,引入指数加权遗忘机制进行时变特性跟踪,能够在激励未知的情况下仅基于响应数据准确快速辨识运载火箭的时变模态。以谷神星一号运载火箭为例,开展飞行遥测数据的快速处理,准确辨识发射准备阶段和飞行阶段的关键低阶时变模态,辨识结果与有限元分析结果的变化规律相互吻合,验证了所提时变模态仅输出递推辨识方法是有效可行的,服务了运载火箭有限元模型修正和姿控系统设计的实际工程需求。

关键词：运载火箭时变模态参数谷神星一号递推辨识

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含复杂裂隙网络岩质边坡三维稳定性计算方法

水电能源科学 2024年第6期42卷 93-97页

作者：马玉福刘建设龚文平李馨馨中国地质大学(武汉)工程学院湖北武汉430074 西北核技术研究所陕西西安710024

岩质边坡稳定性主要受控于结构面的空间组合关系,二维稳定性计算结果往往忽略结构面切割的空间效应,无法准确反映其真实稳定性情况。基于离散裂隙网络模型(DFN)提出了考虑复杂裂隙网络分布的岩质边坡三维稳定性计算方法,该模拟方法假定... 详细信息

岩质边坡稳定性主要受控于结构面的空间组合关系,二维稳定性计算结果往往忽略结构面切割的空间效应,无法准确反映其真实稳定性情况。基于离散裂隙网络模型(DFN)提出了考虑复杂裂隙网络分布的岩质边坡三维稳定性计算方法,该模拟方法假定岩体由岩块和裂隙面组成,分别采用实体单元和无厚度摩擦接触界面单元模拟,基于有限元强度折减法求得岩质边坡的潜在滑动面及安全系数。结果表明,该方法可有效分析含多条裂隙面三维边坡稳定性;二维平面应变模型无法准确反映真实三维边坡失稳问题,忽略三维效应的边坡稳定性分析易出现过于保守设计的情况;在保证精度的前提下,所提方法可有效减小前处理网格剖分难度,对于解决含复杂裂隙网络岩质边坡三维数值模拟问题具有优势。

关键词：边坡稳定性裂隙网络有限元强度折减法三维模型无厚度摩擦接触界面单元

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Difference in microstructural characteristics of stamp-charged coke and gravity-charged coke with approximate macroscopic performance

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Journal of Iron and Steel Research(International) 2024年第5期31卷 1050-1062页

作者： Chong Zou Zheng-yan Huang jian-yun Li Bin Li Shi-wei liu Yuan she School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an710311ShaanxiChina Technical Center of Shandong Iron and Steel Co. Ltd.(Laiwu Branch)Jinan271104ShandongChina

The microstructural characteristics including optical texture,porosity and pore structure and chemical structure of stamp-charged coke(SCC)and gravity-charged coke(GCC)with similar conventional macro-indicators were investigated,and the properties including micro-strength,reactivity of coke matrix and that after alkali enrichment were comparatively studied by various characterization *** anisotropic structure of SCC is composed of high content of fine mosaic texture,while the content of medium mosaic texture,coarse texture and fibrous texture is *** statistical average shows that the fine mosaic average of SCC(24.89%)is 3.78 times the GCC average(6.58%),and the coarse mosaic average(1.24%)is only about 1/3 of the GCC average(3.43%).The porosity of SCC is lower than that of GCC,but tamping process does not lead to the fact that the number of closed pores of SCC is significantly lower than that of *** the structure of SCC is compact,its pore number is large and the pore wall is *** of coke with diameter less than 150 nm seem unaffected by tamping *** aromatic structure of SCC was less ordered than that of GCC,which was speculated to be related to the addition of more low metamorphic coal in *** microscopic strength and structural strength of SCC are lower than those of *** reactivity of coke matrix is affected by the specific surface area,but it is not the determining factor of its *** improvement in dissolution reactivity of coke after potassium enrichment is independent of coke type.

关键词： Stamp-charged coke Optical texture Porosity Microstructure Reactivity

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Chinese Physics Letters 2014年第3期31卷 14-17页

作者： ZHAO Hu LI Tie-Fu liu jian-she CHEN Wei Institute of Microelectronics Tsinghua National Laboratory of Information Science and Technology Tsinghua University Beijing 100084

A phase-slip flux qubit, exactly dual to a charge qubit, is composed of a superconducting loop interrupted by a phase-slip junction. We propose a tunable phase-slip flux qubit by replacing the phase-slip junction with a charge-related superconducting quantum interference device （SQUID） consisting of two phase-slip junctions connected in series with a superconducting island. This charge-SQUID acts as an effective phase-slip junction controlled by the applied gate voltage and can be used to tune the energy-level splitting of the qubit. In addition, we show that a large inductance inserted in the loop can reduce the inductance energy and consequently suppress the dominating flux noise of the phase-slip flux qubit. This enhanced phase-slip flux qubit is exactly dual to a transmon qubit.

关键词： SQUIDs

Fabrication of a novel electrochemical sensor based on MnFe_(2)O_(4)/graphene modified glassy carbon electrode for the sensitive detection of bisphenol A

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Journal of Central South University 2024年第6期31卷 1856-1869页

作者： GAO Si-lei TANG jian-she XIANG Li LONG Jin-wei Department of Environmental and Energy Engineering Anhui Jianzhu UniversityHefei 230601China Anhui Provincial Key Laboratory of Environmental Pollution Control and Resource Reuse Hefei 230601China

Manganese ferrite(MnFe_(2)O_(4))has the advantages of simple preparation,high resistivity,and high crystal ***,we have developed an electrochemical sensor utilizing graphene and MnFe_(2)O_(4) nanocomposites modified glassy carbon electrode(GCE),which is very efficient and sensitive to detect bisphenol A(BPA).MnFe_(2)O_(4)/graphene(GR)was synthesized by immobilizing the MnFe_(2)O_(4) microspheres on the graphene nanosheets via a simple one-pot solvothermal *** morphology and structure of the MnFe_(2)O_(4)/GR nanocomposite have been characterized through scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).In addition,electrochemical properties of the modified materials are comparably explored by means of cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS)and differential pulse voltammetry(DPV).Under the optimal conditions,the proposed electrochemical sensor for the detection of BPA has a linear range of 0.8-400μmol/L and a detection limit of 0.0235μmol/L(S/N=3)with high sensitivity,good selectivity and high *** addition,the proposed sensor was used to measure the content of BPA in real water samples with a recovery rate of 97.94%-104.56%.At present,the synthesis of MnFe_(2)O_(4)/GR provides more opportunities for the electrochemical detection of BPA in practical applications.

关键词： MnFe_(2)O_(4) graphene electrochemical sensor bisphenol A

Automated,economical,and environmentally-friendly asphalt mix design based on machine learning and multi-objective grey wolf optimization

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第3期11卷 381-405页

作者： jian liu Fangyu liu Linbing Wang Department of Civil and Environmental Engineering Virginia Polytechnic Institute and State UniversityBlacksburgVA 24061USA School of Environmental CivilAgricultural and Mechanical EngineeringUniversity of GeorgiaAthensGA 30602USA Illinois Center for Transportation Department of Civil and Environmental EngineeringUniversity of Illinois Urbana-ChampaignUrbanaIL 61801USA

The increasing impact of the greenhouse effect on ecosystems is prompting transportation agencies to seek methods for reducing CO_(2)emissions during pavement construction and ***,the laboratory mix design process,which involves selecting aggregate gradation and binder content,is time-consuming and *** accelerate the traditional mix design procedure,this study presented a mix design procedure that can automatically determine gradation and binder content based on machine learning(ML)and a meta-heuristic ***,ML approaches were employed to model the relationship between volumetric properties(mixture bulk specific gravity(Gmb)and air void(VV))and both mixture component properties and mixture proportion,based on a dataset collected from literature with 660 mixture *** with the prediction of ML models and the modified multi-objective grey wolf optimization(MOGWO)algorithm,an automatic asphalt mix design was proposed to pursue three goals,including VV,cost,and CO_(2)*** results indicated that least squares support vector regression(LSSVR)and e Xtreme gradient boosting(XGBoost)achieved the highest prediction accuracies(correlation coefficient:0.92 for VV and 0.96 for Gmb).The MOGWO algorithm successfully found the 26 optimal mix designs for the case of VV *** ***_(2)*** to the traditional laboratory design,the optimal mixture with VV of4%achieves a cost saving of 2.46%and a reduction of 4.03%in carbon *** volumetric properties of the mixtures output by the approach also align closely with values measured in a laboratory.

关键词： Asphalt mix design Machine learning MOGWO CO_(2)emission Volumetric properties

An Industrial Intrusion Detection Method Based on Hybrid Convolutional Neural Networks with Improved TCN

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Computers, Materials & Continua 2024年第1期78卷 411-433页

作者： Zhihua liu shengquan liu jian Zhang College of Computer Science and Technology Xinjiang UniversityXinjiang Uygur Autonomous RegoinUrumqi830000China

Network intrusion detection systems(NIDS)based on deep learning have continued to make significant ***,the following challenges remain:on the one hand,simply applying only Temporal Convolutional Networks(TCNs)can lead to models that ignore the impact of network traffic features at different scales on the detection *** the other hand,some intrusion detection methods considermulti-scale information of traffic data,but considering only forward network traffic information can lead to deficiencies in capturing multi-scale temporal *** address both of these issues,we propose a hybrid Convolutional Neural Network that supports a multi-output strategy(BONUS)for industrial internet intrusion ***,we create a multiscale Temporal Convolutional Network by stacking TCN of different scales to capture the multiscale information of network ***,we propose a bi-directional structure and dynamically set the weights to fuse the forward and backward contextual information of network traffic at each scale to enhance the model’s performance in capturing the multi-scale temporal features of network *** addition,we introduce a gated network for each of the two branches in the proposed method to assist the model in learning the feature representation of each *** experiments reveal the effectiveness of the proposed approach on two publicly available traffic intrusion detection datasets named UNSW-NB15 and NSL-KDD with F1 score of 85.03% and 99.31%,respectively,which also validates the effectiveness of enhancing the model’s ability to capture multi-scale temporal features of traffic data on detection performance.

关键词： Intrusion detection industrial internet channel spatial attention multiscale features dynamic fusion multi-output learning strategy

Synergism of solar-driven interfacial evaporation and photo-Fenton Cr(Ⅵ) reduction by sustainable Bi-MOF-based evaporator from waste polyester

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Journal of Energy Chemistry 2024年第7期94卷 527-540页

作者： Zifen Fan Jie liu Huajian liu Lijie liu Yan she Xueying Wen Huiyue Wang Guixin Hu Ran Niu jiang Gong Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureHubei Engineering Research Center for Biomaterials and Medical Protective MaterialsSemiconductor Chemistry CenterSchool of Chemistry and Chemical EngineeringHuazhong University of Science andTechnologyWuhan430074HubeiChina

The integration of interfacial solar steam generation and photocatalytic degradation technology has pro-vided a promising platform to simultaneously produce freshwater and degrade ***,con-structing low-cost,multi-functional evaporators for treating Cr(Ⅵ)-polluted water remains challenging,and the synergistic mechanism on Cr(Ⅵ)reduction is ***,we propose the combined strategy of ball milling and solution mixing for the sustainable production of Bi-MOF microrod from waste poly(ethylene terephthalate),and construct Bi-MOF-based solar evaporators for simultaneous photo-Fenton Cr(Ⅵ)reduction and freshwater ***,the evaporator comprised of Bi-MOF microrod and graphene nanosheet possesses high light absorption,efficient photothermal conversion,and good hydro-philic *** to the advantages,the hybrid evaporator exhibits the evaporation rate of 2.16 kg m^(-2) h^(-1) and evaporation efficiency of 87.5%under 1 kW m^(-2) of *** integrating with photo-Fenton reaction,the Cr(Ⅵ)reduction efficiency is 91.3%,along with the reaction kinetics of 0.0548 min^(-1),surpassing many advanced *** the outdoor freshwater production and Cr(Ⅵ)reduction,the daily accumulative water yield is 5.17 kg m^(-2) h^(-1),and the Cr(Ⅵ)reduction efficiency is 99.9%.Furthermore,we prove that the localization effect derived from the interfacial solar-driven evap-oration enhances H_(2)O_(2) activation for the photo-Fenton reduction of Cr(Ⅵ).Based on the result of density functional theory,Bi-MOF microrod provides rich active centers for H_(2)O_(2) activation to produce active sites such as e-or-O_(2).This study not only proposes a new strategy to construct multi-functional solar evaporators for freshwater production and catalytic reduction of pollutants,but also advances the chem-ical upcycling of waste polyesters.

关键词： Interfacial solar steam generation Cr(VI)reduction Photo-Fenton reaction Metal-organic framework Waste plastic upcycling

Janus mesoporous nanoparticles enable building biological logic systems

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Science China Chemistry 2024年第1期67卷 316-318页

作者： Haitao Li jian liu State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China College of Chemistry and Chemical Engineering Inner Mongolia UniversityHohhot 010021China

This highlight is inspired by a recent article in Nature Chemistry[1],in which Zhao and co-workers from Fudan University developed an innovative emulsion-orientated anisotropic assembly method for the controllable fabrication of MSN&mPDA(mesoporous silica nanoparticles=MSN,mesoporous polydopamine=mPDA)Janus mesoporous nanoparticles and used them to build biological logic *** reported Janus mesoporous nanoparticles have delicate structures and are well-controlled,and the authors also demonstrated the unique performance of this material at the application end.

关键词： enable emulsion silica