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Characteristics study on the oscillation onset and damping of a traveling-wave thermoacoustic prime mover

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第7期9卷 944-949页

作者： Tao jin Chang-song mao Ke TANG Hao ZHENG Guo-bang chen Institute of Refrigeration and Cryogenics Zhejiang University Hangzhou 310027 China

This paper focuses on the temperature and pressure characteristics of a Swift-Backhaus type traveling-wave thermoacoustic prime mover during its onset and damping processes,in order to understand the intrinsic mechanism of thermoacoustic oscillation onset and the feasibility of using low-grade thermal energy based on a low onset temperature. The influences of heat input and filling pressure on hysteretic loop,due to the noncoincidence between onset and damping processes,are measured and analyzed. The condition for the occurrence of hysteresis is also briefly discussed.

关键词： Thermoacoustics Onset and damping Hysteretic loop

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嵌入式系统的需求描述综述

软件学报 2025年第1期36卷 27-46页

作者：陈小红刘少彬金芝上海市高可信计算重点实验室(华东师范大学) 高可信软件技术教育部重点实验室(北京大学) 北京大学计算机学院

随着嵌入式系统的广泛应用,其需求正变得越来越复杂,需求分析成为嵌入式系统开发的关键阶段,如何准确地建模和描述需求成为首要问题.系统地调研嵌入式系统的需求描述,并进行全面的比较分析,以便更深入地理解嵌入式系统需求的核心关注点... 详细信息

随着嵌入式系统的广泛应用,其需求正变得越来越复杂,需求分析成为嵌入式系统开发的关键阶段,如何准确地建模和描述需求成为首要问题.系统地调研嵌入式系统的需求描述,并进行全面的比较分析,以便更深入地理解嵌入式系统需求的核心关注点.首先采用系统化文献综述方法,对1979年1月–2023年11月间发表的相关文献进行识别、筛选、汇总和分析.通过自动检索和滚雪球等检索过程,筛选出150篇与主题密切相关的文献,力求文献综述的全面性.其次,从需求描述关注点、需求描述维度、需求分析要素等方面,分析现有嵌入式需求描述语言的表达能力.最后,总结现有嵌入式系统软件需求描述所面临的挑战,并针对嵌入式软件智能合成任务,提出对嵌入式系统需求描述方法表达能力的要求.

关键词：嵌入式系统需求描述需求描述语言需求分析系统需求

Effects of Drying Processes on the Antioxidant Properties in Sweet Potatoes

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Agricultural Sciences in China 2010年第10期9卷 1522-1529页

作者： YANG jing chen jin-feng ZHAO Yu-ying mao Lin-chun Department of Food Science and Nutrition College of Biosystem Engineering and Food Science Zhejiang University Hangzhou 310029 P.R. China

The effects of different drying methods （hot-air drying, microwave drying and vacuum-freeze drying） on the antioxidant activity and antioxidants in sweet potato （lpomoea batatas L. Lain.） tubers were investigated to determine the potential drying process. Sweet potato tubers were cut into 5 mm thick slices, steamed at 100℃ for 10 rain, then dried in either hotair, microwave, or vacuum-freeze. The dried sweet potatoes in microwave possessed the highest antioxidant activity, while the lowest activity was observed in hot-air dried samples. The phenolic contents were positively correlated with scavenging activity and reducing power of DPPH^＋. The microwave drying retains the highest antioxidant activity with the highest content of phenolic compounds in dried sweet potatoes. β-carotene and ascorbic acid showed minor contribution to the antioxidant activity in dried sweet potatoes.

关键词： sweet potato (lpomoea batatas L. Lam.) drying antioxidant activity antioxidants

The effect of precipitates on the fracture behavior and tensile properties of Mg-14Gd-0.5Zr(wt.%)alloy

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Journal of Materials Science & Technology 2024年第13期180卷 226-242页

作者： Chunxiao Li Jianxiong Wei Jianfeng jin Hong Yan Zhiwei Shan Yaozong mao Rongshi chen School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering Shandong University of Science and TechnologyQingdao 266590China Beijing Institute of Space Long March Vehicle Beijing 100076China Center for Advancing Materials Performance From the Nanoscale(CAMP-Nano)&Hysitron Applied Research Center in China(HARCC) State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an 710049China Key Laboratory of Advanced Aluminium Materials and Technology Binzhou Institute of TechnologyWeiqiao-UCAS Science and Technology ParkBinzhou 256606China

The effect of precipitation aging on the fracture behavior of cast Mg-14.23Gd-0.45Zr(wt.%)alloy at room temperature has been studied in this *** tensile and three-point bending tests were conducted on samples peak-aged at 175,200,225,and 250 ℃.Notably,samples aged at 175 ℃ and 200 ℃ exhibited premature fracture during the uniaxial tensile *** fractographic observations of the tensile test samples and electron backscattered diffraction(EBSD)analysis on the samples sub-jected to three-point bending tests,a preferential formation of cleavage cracks in samples aged at 175 ℃ and 200 ℃ was identified as the reason for their premature *** X-ray diffraction(XRD)results and transmission electron microscopy(TEM)observations of precipitates indicate that the dominant strengthening precipitates in all peak-aged samples are of theβ'phase,and their size significantly influences the formation of cleavage *** phenomenon is attributed to the shearing mechanism of ***,the smaller β'precipitates formed under the aging temperature of 175-200 ℃ are susceptible to dislocation shearing,leading to the formation of cleavage *** contrast,the larger size of β'precipitates formed under the aging temperature of 225-250 ℃ provides resistance to shearing,resulting in the restrained formation of cleavage cracks and ultimately contributing to the enhancement of the ultimate tensile strength.

关键词： Fracture Mg-RE alloy Precipitate Aging treatment Mechanical property

基于全转录组测序探讨褪黑素抑制神经胶质瘤细胞增殖的机制

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中国药理学通报 2025年第1期41卷 163-170页

作者：徐丽陈秀娇郑伟男毛馨琳林丽彬谢群金清东莆田学院基础医学院福建莆田351100 莆田学院基础医学院肿瘤转化医学福建省高校重点实验室福建莆田351100 莆田市第一医院神经外科福建莆田351100

目的全转录组测序检测神经胶质瘤细胞非编码RNA(ncRNA)表达谱并构建ceRNA网络,揭示ncRNA参与褪黑素抑制神经胶质瘤细胞增殖的分子机制。方法0、2、4、6、8 mmol·L^(-1)褪黑素干预神经胶质瘤细胞24、48、72 h,CCK-8检测褪黑素对细胞增... 详细信息

目的全转录组测序检测神经胶质瘤细胞非编码RNA(ncRNA)表达谱并构建ceRNA网络,揭示ncRNA参与褪黑素抑制神经胶质瘤细胞增殖的分子机制。方法0、2、4、6、8 mmol·L^(-1)褪黑素干预神经胶质瘤细胞24、48、72 h,CCK-8检测褪黑素对细胞增殖的抑制作用;0、4 mmol·L^(-1)褪黑素干预U251细胞24h后,全转录组测序检测差异表达miRNA(DEmiRNA)、lncRNA(DElncRNA)、mRNA(DEmRNA),对DEmRNA进行GO和KEGG富集分析;构建ceRNA网络,采用qRT-PCR验证ceRNA关键基因表达。结果褪黑素呈时间-剂量依赖性抑制神经胶质瘤细胞增殖;全转录组测序筛选出0 mmol·L^(-1)与4 mmol·L^(-1)褪黑素组DEmRNA 5049个、DElncRNA 635个、DEmiRNA 146个;DEmRNA主要富集在铁死亡、mTOR信号通路、FoxO信号通路、细胞周期等癌症相关信号通路;ceRNA网络包含4个lncRNA、3个miRNA和48个mRNA,qRT-PCR验证U251细胞hsa-miR-129-5p、hsa-miR-362-5p、LINC00707和SLC16A1-AS1表达与测序结果一致,U87细胞的基因表达与测序结果基本一致。结论褪黑素通过ncRNA差异表达,影响癌症相关信号通路,进而抑制神经胶质瘤细胞增殖;LINC00707、SLC16A1-AS1、hsa-miR-129-5p、hsa-miR-362-5p构成的ceRNA网络可能参与褪黑素抑制神经胶质瘤细胞增殖的分子机制。

关键词：褪黑素神经胶质瘤全转录组测序 ceRNA网络 hsa-miR-129-5p hsa-miR-362-5p

Risk Status Identification During the Takeover of Conditionally Automated Vehicles 32

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Risk Status Identification During the Takeover of Conditiona...

Mineralogy of the deep lower mantle in the presence of H2O

第32届中国控制与决策会议

作者： mao Peng chen jin Sun Dihua School of Automation Chongqing University Key Laboratory of Dependable Service Computing in Cyber Physical Society of Ministry of Education

ISBN: (数字)9781728158556

ISBN: (纸本)9781728158556;9781728158563

In order to identify the risk status during the takeover from automated driving to manual driving in dangerous traffic situations,this study investigated their performance during the takeover based on *** experiment invited 38 *** all held a valid driving license.A risk status identification model was proposed based on the information of vehicle status and traffic environment *** to the rate of electrocardiogram（ECG） and the performance of takeover,the risk status was classified into three *** Pearson correlation coefficient algorithm,seven factors were selected as the feature ***,the algorithm of Random Forest（RF） was employed to establish the takeover risk status identification *** results show that the accuracy of RF is 98.8%,increasing 10.4%,17.7% and 7.3% compared with Support Vector Machine（SVM）,Classification and Regression Tree（CART） and Back Propagation Neural Network,and each risk level has good prediction ***,the results show that the space headway,longitudinal acceleration and lane departure have a great influence on the risk level,and the space headway has the strongest impact on the degree of danger during the takeover of control in Conditionally Automated Vehicles.

关键词： Automated Driving Experimental Research Takeover Risk Status Identification Driving Simulator

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National Science Review 2021年第4期8卷 21-28页

作者： Qingyang Hu jin Liu Jiuhua chen Bingmin Yan Yue Meng Vitali B.Prakapenka Wendy L.mao Ho-Kwang mao Center for High Pressure Science and Technology Advanced Research(HPSTAR) Department of Geological Sciences Stanford University Center for Study of Matter under Extreme Conditions Department of Mechanical and Materials Engineering Florida International University High Pressure Collaborative Access Team(HPCAT) X-ray Science Division Argonne National Laboratory Center for Advanced Radiation Sources University of Chicago

Understanding the mineralogy of the Earth's interior is a prerequisite for unravelling the evolution and dynamics of our planet. Here, we conducted high pressure-temperature experiments mimicking the conditions of the deep lower mantle（DLM, 1800–2890 km in depth） and observed surprising mineralogical transformations in the presence of water. Ferropericlase,（Mg,Fe）O, which is the most abundant oxide mineral in Earth, reacts with H;2;O to form a previously unknown（Mg,Fe）O;2;H;x;（x ≤ 1）phase. The（Mg,Fe）O;2;H;x;has a pyrite structure and it coexists with the dominant silicate phases,bridgmanite and post-perovskite. Depending on Mg content and geotherm temperatures, the transformation may occur at 1800 km for(Mg;0.6;Fe;0.4;)O or beyond 2300 km for(Mg;0.7;Fe;0.3;)O. The（Mg,Fe）O;2;H;x;is an oxygen excess phase that stores an excessive amount of oxygen beyond the charge balance of maximum cation valences(Mg;2+;, Fe;3+;and H;+;). This important phase has a number of far-reaching implications including extreme redox inhomogeneity, deep-oxygen reservoirs in the DLM and an internal source for modulating oxygen in the atmosphere.

关键词： lower mantle water-mantle interaction ferropericlase high pressure mantle mineralogy

Simulation and experimental improvement on a small-scale Stirling thermo-acoustic engine

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Frontiers in Energy 2016年第1期10卷 37-45页

作者： mao chen Yonglin JU Institute of Refrigeration and Cryogenics Shanghai Jiao TongUniversity Shanghai 200240 China

Compared with the traditional engines, the thermo-acoustic engines are relatively new and can act as the linear compressors for refrigerators. Many institutes have shown great interest in this kind of machine for its absence of moving mechanical part. In this paper, the influence of the dimensions of the main parts of the small- scale Stifling thermo-acoustic engine was numerically simulated using a computer code called DeltaEC. The resonator and the resonator cavity were found to be the most convenient and effective in improving the perfor- mance of the engine. Based on the numerical simulation, a small-scale Stifling thermo-acoustic engine were constructed and experimentally investigated. Currently, with a resonator length of only 1 m, the working frequency of the engine was decreased to 90 Hz and the onset temperature difference was decreased to 198.2 K.

关键词： thermo-acoustic Stifling engine small-scale simulation experiment

Experimental study of hydrogen-rich/oxygen-rich gas–gas injectors

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Chinese Journal of Aeronautics 2013年第5期26卷 1164-1172页

作者： jin Ping Li mao Cai Guobiao School of Astronautics Beihang University

Five types of coaxial injectors were investigated experimentally using hot hydrogen-rich gas and oxygen-rich gas, which were respectively provided by a GH2/GO2 hydrogen-rich perburner and a GH2/GO2 oxygen-rich preburner. The injectors were the shear coaxial injector, the oxidizer post expansion coaxial injector, the fuel impinging coaxial injector, the central body coaxial injector, and the shear tri-coaxial injector. The characteristic velocity efficiency and the combustor＇s wall temperatures were obtained for different design parameters through the experiments. It can be con- cluded that angles of the oxidizer post expansion and the fuel impinging have little influence on the combustion performance and the wall temperatures. The contact area between fuel and oxidizer and the mass flow rate have significant impacts on the combustion performance. The shear tri-coaxial injector has the best combustion performance but also the highest wall temperatures among the five types of injectors.

关键词： Combustion performance Experiment Gas-gas injector High mass flow rate Wall temperature