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高温后水泥砂浆-花岗岩复合层动态力学性能试验研究

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振动与冲击 2024年第11期43卷 176-184页

作者：顾琳琳尹克飞王振吴汩何鹏涛南京理工大学安全科学与工程学院南京210094 南京理工大学机械工程学院南京210094 南京玻璃纤维研究设计院有限公司南京210012

为研究高温后水泥砂浆-花岗岩复合层的动态力学特性,采用分离式霍普金森压杆(SHPB)设备,以温度和加载速率为可变参数,开展了复合层试件动态压缩试验及静压对比试验。结果表明:动态抗压强度和动态强度增长因子(dynamic intensity factor,... 详细信息

为研究高温后水泥砂浆-花岗岩复合层的动态力学特性,采用分离式霍普金森压杆(SHPB)设备,以温度和加载速率为可变参数,开展了复合层试件动态压缩试验及静压对比试验。结果表明:动态抗压强度和动态强度增长因子(dynamic intensity factor, DIF)均有显著的应变率效应,应变率低于45 s~(-1)时DIF随温度升高单调减小,高于45 s~(-1)后DIF随温度升高先减小后增大;高温后复合层界面黏结减弱,随着温度升高水泥砂浆和花岗岩破坏形态差异化增大;复合层试件削波耗能特性表现出加载速率低敏感和温度高敏感。峰值应力比和耗能率不随加载速率的改变而发生明显变化,高温后复合层等效波阻抗下降,削波能力得到增强而耗能效果受到削弱;随着温度升高,入射能更多地转化为反射能,透射能及破坏耗能的占比下降。

关键词：分离式霍普金森压杆(SHPB) 复合层高温冲击荷载动态力学性能

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土中钢板-混凝土筒结构抗爆性能研究

工程爆破 2024年第3期30卷 20-28页

作者：朱黄浩顾琳琳王振吴汩李胡军南京理工大学安全科学与工程学院南京210094 南京理工大学机械工程学院南京210094 南京玻璃纤维研究设计院有限公司南京210012

为探究地下爆炸荷载作用下土中钢板-混凝土筒结构的抗爆性能,采用多物质流固耦合计算方法,揭示了冲击波在土体介质中的传播规律,分析了钢板-混凝土筒结构的动力响应与损伤机理,开展了爆炸模型试验,获得了筒体附近的土压力分布及其迎爆... 详细信息

为探究地下爆炸荷载作用下土中钢板-混凝土筒结构的抗爆性能,采用多物质流固耦合计算方法,揭示了冲击波在土体介质中的传播规律,分析了钢板-混凝土筒结构的动力响应与损伤机理,开展了爆炸模型试验,获得了筒体附近的土压力分布及其迎爆面的变形时程曲线,并验证了数值模拟的准确性。在此基础上,与传统钢筋混凝土筒结构抗爆性能对比,分别评价了两种结构形式的破坏模式与损伤程度。结果表明,同等用钢率下,钢板-混凝土筒体抗冲击性能更好。

关键词：地下爆炸荷载数值模拟钢板-混凝土筒结构动态响应损伤评价

含水乙醇/RP-3航空煤油混合燃料的层流燃烧速度

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航空动力学报 2024年第1期39卷 1-11页

作者：刘宇周博谷午饶大为马洪安曾文沈阳航空航天大学航空发动机学院、辽宁省航空推进系统先进测试技术重点实验室沈阳110136

采用定容燃烧实验装置获得初始压力为0.1 MPa、初始温度为450 K、当量比为0.8~1.4工况下乙醇/RP-3航空煤油预混火焰和含水乙醇/RP-3航空煤油预混火焰的层流燃烧速度(LBVs),并分析了乙醇掺混比、乙醇含水量、当量比等因素对混合燃料层流... 详细信息

采用定容燃烧实验装置获得初始压力为0.1 MPa、初始温度为450 K、当量比为0.8~1.4工况下乙醇/RP-3航空煤油预混火焰和含水乙醇/RP-3航空煤油预混火焰的层流燃烧速度(LBVs),并分析了乙醇掺混比、乙醇含水量、当量比等因素对混合燃料层流燃烧速度的影响。研究表明:随着乙醇掺混比的增加,乙醇/RP-3航空煤油混合燃料层流燃烧速度增大;当RP-3航空煤油中乙醇掺混比一定时,随着乙醇含水量的增加,含水乙醇/RP-3混合燃料层流燃烧速度减小。由燃烧反应动力学分析可知,混合燃料的层流燃烧速度受动力学、热力学等的综合影响。本研究所获实验数据能够为生物乙醇燃料在航空发动机中的应用提供理论基础和技术支持。

关键词：定容燃烧 RP-3航空煤油含水乙醇层流燃烧速度(LBV) 燃烧反应动力学

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天然气层流燃烧特性的实验与数值计算

航空动力学报 2024年第2期39卷 57-66页

作者：党嘉莹曾文陈潇潇谷午胡二江马宏宇沈阳航空航天大学航空发动机学院沈阳110136 西安交通大学动力工程多相流国家重点实验室西安710049 中国航发沈阳发动机研究所沈阳110015

在定容弹中试验测量了压力分别为0.1、0.2、0.3 MPa,当量比范围为0.7~1.4,温度分别为300、350、400 K,O_(2)体积分数分别为15%、18%、21%,CO_(2)体积分数分别为0%、10%、20%,H2O体积分数分别为0%、10%、20%工况条件下天然气(0.9甲烷/0.0... 详细信息

在定容弹中试验测量了压力分别为0.1、0.2、0.3 MPa,当量比范围为0.7~1.4,温度分别为300、350、400 K,O_(2)体积分数分别为15%、18%、21%,CO_(2)体积分数分别为0%、10%、20%,H2O体积分数分别为0%、10%、20%工况条件下天然气(0.9甲烷/0.07乙烷/0.03丙烷,摩尔分数)的火焰发展特性以及层流燃烧速度。同时,利用敏感性分析等方法构建了天然气的简化反应机理(40种组分和189个反应),并对其层流燃烧速度进行了数值计算。结果表明:当当量比由0.7提升至1.4时,天然气的层流燃烧速度先升高后降低,其峰值在当量比1.1附近;层流燃烧速度随着初始温度、O_(2)体积分数的增多或初始压力、CO_(2)及H2O体积分数的减少而逐渐得到提升。构建的天然气简化反应机理可以较好的预测层流燃烧速度随当量比变化的整体趋势;但是,部分工况下预测值略低于试验值。

关键词：天然气层流燃烧速度定容弹简化反应机理敏感性分析

Added value of ratio of cross diameters of the appendix in ultrasound diagnosis of acute appendicitis

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World Journal of Gastrointestinal Surgery 2024年第1期16卷 21-28页

作者： Feng-Wa gu Si-Ze wu Department of Ultrasound The First Affiliated Hospital of Hainan Medical UniversityHaikou 570102Hainan ProvinceChina

BACKGROUND The maximum outer diameter(MOD)of the appendix is an essential parameter for diagnosing acute appendicitis,but there is space for improvement in ultrasound(US)diagnostic performance.AIM To investigate whether combining the ratio of the cross diameters(RATIO)of the appendix with MOD of the appendix can enhance the diagnostic performance of acute appendicitis.METHODS A retrospective study was conducted,and medical records of 233 patients with acute appendicitis and 112 patients with a normal appendix were reviewed.The MOD and RATIO of the appendix were calculated and tested for their diagnostic performance of acute appendicitis,both individually and in combination.RESULTS The RATIO for a normal appendix was 1.32±0.16,while for acute appendicitis it was 1.09±0.07.The cut-off value for RATIO was determined to be≤1.18.The area under the receiver operating characteristic curve(AUC)for diagnosing acute appendicitis using RATIO≤1.18 and MOD>6 mm was 0.870 and 0.652,respectively.There was a significant difference in AUC between RATIO≤1.18 and MOD>6 mm(P6 mm with MOD>6 mm alone,the combination showed increased specificity,positive predictive value(PPV),and AUC.However,the sensitivity and negative predictive value decreased.CONCLUSION Combining RATIO of the appendix≤1.18 and MOD>6 mm can significantly improve the specificity,PPV,and AUC in the US diagnosis of acute appendicitis.

关键词： Acute appendicitis Diameter Ratio Diagnosis Ultrasound

Cell Consistency Evaluation Method Based on Multiple Unsupervised Learning Algorithms

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Big Data Mining and Analytics 2024年第1期7卷 42-54页

作者： Jiang Chang Xianglong gu Jieyun wu Debu Zhang Stellantis China Technology Center Shanghai 200233China

Unsupervised learning algorithms can effectively solve sample imbalance.To address battery consistency anomalies in new energy vehicles,we adopt a variety of unsupervised learning algorithms to evaluate and predict the battery consistency of three vehicles using charging fragment data from actual operating conditions.We extract battery-related features,such as the mean of maximum difference,standard deviation,and entropy of batteries and then apply principal component analysis to reduce the dimensionality and record the amount of preserved information.We then build models through a collection of unsupervised learning algorithms for the anomaly detection of cell consistency faults.We also determine whether unsupervised and supervised learning algorithms can address the battery consistency problem and document the parameter tuning process.In addition,we compare the prediction effectiveness of charging and discharging features modeled individually and in combination,determine the choice of charging and discharging features to be modeled in combination,and visualize the multidimensional data for fault detection.Experimental results show that the unsupervised learning algorithm is effective in visualizing and predicting vehicle core conformance faults,and can accurately predict faults in real time.The“distance+boxplot”algorithm shows the best performance with a prediction accuracy of 80%,a recall rate of 100%,and an F1 of 0.89.The proposed approach can be applied to monitor battery consistency faults in real time and reduce the possibility of disasters arising from consistency faults.

关键词： battery consistency charging segment data unsupervised learning

Mechanism Design for Ancillary Service Market Considering Social Welfare and Fairness

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1000-1010页

作者： Zhi wu Yuanxi wu Wei gu Zheng Xu Shu Zheng Jingtao Zhao School of Electrical Engineering Southeast UniversityNanjing 210096China NARI Technology Co. Ltd.Nanjing 211106China IEEE CSEE

Increasing penetration of distributed energy resources in the distribution network(DN)is threatening safe operation of the DN,which necessitates setup of the ancillary service market in the DN.In the ancillary service market,distribution system operator(DSO)is responsible for safety of the DN by procuring available capacities of aggregators.Unlike existing studies,this paper proposes a novel market mechanism composed of two parts:choice rule and payment rule.The proposed choice rule simultaneously considers social welfare and fairness,encouraging risk-averse aggregators to participate in the ancillary service market.It is then formulated as a linear programming problem,and a distributed solution using the multi-cut Benders decomposition is presented.Moreover,successful implementation of the choice rule depends on each aggregator’s truthful adoption of private parameters.Therefore,a payment rule is also designed,which is proved to possess two properties:incentive compatibility and individual rationality.Simulation results demonstrate effectiveness of the proposed choice rule on improving fairness and verify properties of the payment rule.

关键词： Aggregator ancillary service market distributed mechanism fairness mechanism design

Efficient degradation of aqueous dichloromethane by an enhanced microbial electrolysis cell:Degradation kinetics,microbial community and metabolic mechanisms

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Journal of Environmental Sciences 2024年第5期139卷 150-159页

作者： Meng wu Di Zhao Bing gu ZiruWang Jun Hu Zhiliang Yu Jianming Yu College of Environment College of Biotechnology and BioengineeringCollaborative Innovation Center of Yangtze River Delta Region Green PharmaceuticalsZhejiang University of TechnologyHangzhou 310014China Shentuo Environment(Hangzhou)Co.Ltd. Hangzhou 311121China Zhejiang Tianyi Environmental Co.Ltd. Hangzhou 310000China

Dichloromethane(DCM)has been listed as a toxic and harmful water pollutant,and its re moval needs attention.Microbial electrolysis cells(MECs)are viewed as a promising alterna tive for pollutant removal,which can be strengthened from two aspects:microbial inocula tion and acclimation.In this study,the MEC for DCM degradation was inoculated with the ac tive sludge enhanced by Methylobacterium rhodesianum H13(strain H13)and then acclimated in the form of a microbial fuel cell(MFC).Both the introduction of strain H13 and the initi ation in MFC form significantly promoted DCM degradation.The degradation kinetics were fitted by the Haldane model,with V_(max),K_(h),K_(i)and v_(max)values of 103.2 mg/L/hr,97.8 mg/L268.3 mg/L and 44.7 mg/L/hr/cm^(2),respectively.The cyclic voltammogram implies that DCM redox reactions became easier with the setup of MEC,and the electrochemical impedance spectrogram shows that the acclimated and enriched microbes reduced the charge transfe resistance from the electrode to the electrolyte.In the biofilm,the dominant genera shifted from Geobacter to Hyphomicrobium in acclimation stages.Moreover,Methylobacterium played an increasingly important role.DCM metabolism mainly occurred through the hydrolytic glutathione S-transferase pathway,given that the gene dcmA was identified rather than the dhlA and P450/MO.The exogenous electrons facilitated the reduction of GSSG,directly o indirectly accelerating the GSH-catalyzed dehalogenation.This study provides support fo the construction of an efficient and stable MEC for DCM removal in water environment.

关键词： Dichloromethane Microbial electrolysis cells Metabolic pathways Electron transfer Degradation kinetics

Layered Coded Cache Placement and Cooperative Delivery with Sharing Links in Satellite-Terrestrial Integrated Networks

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China Communications 2024年第3期21卷 217-229页

作者： gu Shushi Chen Zihan wu Yaonan Zhang Qinyu Wang Ye School of Electronic and Information Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China guangdong Provincial Key Laboratory of Aerospace Communication and Networking Technology Shenzhen 518055China Broadband Communications Research Department Pengcheng LaboratoryShenzhen 518052China

Cooperative utilization of multidimensional resources including cache, power and spectrum in satellite-terrestrial integrated networks(STINs) can provide a feasible approach for massive streaming media content delivery over the seamless global coverage area. However, the on-board supportable resources of a single satellite are extremely limited and lack of interaction with others. In this paper, we design a network model with two-layered cache deployment, i.e., satellite layer and ground base station layer, and two types of sharing links, i.e., terrestrial-satellite sharing(TSS) links and inter-satellite sharing(ISS) links, to enhance the capability of cooperative delivery over STINs. Thus, we use rateless codes for the content divided-packet transmission, and derive the total energy efficiency(EE) in the whole transmission procedure, which is defined as the ratio of traffic offloading and energy consumption. We formulate two optimization problems about maximizing EE in different sharing scenarios(only TSS and TSS-ISS),and propose two optimized algorithms to obtain the optimal content placement matrixes, respectively.Simulation results demonstrate that, enabling sharing links with optimized cache placement have more than 2 times improvement of EE performance than other traditional placement schemes. Particularly, TSS-ISS schemes have the higher EE performance than only TSS schemes under the conditions of enough number of satellites and smaller inter-satellite distances.

关键词： coded content placement cooperative delivery energy efficiency sharing links STINs