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An attention graph stacked autoencoder for anomaly detection of electro-mechanical actuator using spatio-temporal multivariate signals

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CHINESE JOURNAL OF AERONAUTICS 2024年第9期37卷 506-520页

作者： Wang, Jianyu Zhang, Heng Miao, qiang Sichuan Univ Coll Elect Engn Chengdu 610065 Peoples R China

Health monitoring of electro-mechanical actuator (EMA) is critical to ensure the security of airplanes. It is difficult or even impossible to collect enough labeled failure or degradation data from actual EMA. The autoencoder based on reconstruction loss is a popular model that can carry out anomaly detection with only consideration of normal training data, while it fails to capture spatio-temporal information from multivariate time series signals of multiple monitoring sensors. To mine the spatio-temporal information from multivariate time series signals, this paper proposes an attention graph stacked autoencoder for EMA anomaly detection. Firstly, attention graph convolution is introduced into autoencoder to convolve temporal information from neighbor features to current features based on different weight attentions. Secondly, stacked autoencoder is applied to mine spatial information from those new aggregated temporal features. Finally, based on the benchmark reconstruction loss of normal training data, different health thresholds calculated by several statistic indicators can carry out anomaly detection for new testing data. In comparison with traditional stacked autoencoder, the proposed model could obtain higher fault detection rate and lower false alarm rate in EMA anomaly detection experiment. (c) 2024 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.

关键词： Anomaly detection Spatio-temporal informa- tion Multivariate time series sig- nals Attention graph convolu- tion Stacked autoencoder FAULT-DIAGNOSIS

A review on the high energy oxidizer ammonium dinitramide:Its synthesis,thermal decomposition,hygroscopicity,and application in energetic materials

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Defence Technology（防务技术） 2023年第1期19卷 163-195页

作者： Fu-yao Chen Chun-lei Xuan qiang-qiang Lu Lei Xiao Jun-qing Yang Yu-bing Hu Guang-Pu Zhang Ying-lei Wang Feng-qi Zhao Ga-zi Hao Wei Jiang National Special Superfine Powder Engineering Technology Research Center Nanjing University of Science and TechnologyNanjingChina Xi'an Modern Chemistry Research Institute Xi'anChina

Ammonium dinitramide(ADN)is considered as a potential substitute for ammonium perchlorate in energetic materials due to its high density,positive oxygen balance,and halogen-free ***,its application has been severely limited because of its strong hygroscopicity,difficult storage,and incompatibility with isocyanate curing *** order to better bloom the advantages of the highly energetic and environment-friendly ADN in the fields of energetic materials,an in-depth analysis of the current situation and discussion of key research points are particularly *** this paper,a detailed overview on the synthesis,thermal decomposition,hygroscopic mechanism,and antihygroscopicity of ADN has been discussed,its application in powdes and explosives are also presented,and its future research directions are proposed.

关键词： Ammonium dinitramide High energy oxidizer Synthesis Properties Applications

Preparation of Self-limiting Heating Cables with Excellent Processability, Mechanical Properties and PTC Effect via Thermal and Electrical Treatments

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Chinese Journal of Polymer Science 2024年第4期42卷 511-520页

作者： Tian-Hao Yang Tong Wu qiang Fu State Key Laboratory of Polymer Materials Engineering College of Polymer Science and EngineeringSichuan UniversityChengdu610065China State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversityChengdu610065China

Polymer/conductive filler composites have been widely used for the preparation of self-limiting heating cables with the positive temperature coefficient (PTC) effect. The control of conductive filler distribution and network in polymer matrix is the most critical for performance of PTC materials. In order to compensate for the destruction of the filler network structure caused by strong shearing during processing, an excessive conductive filler content is usually added into the polymer matrix, which in turn sacrifices its processability and mechanical properties. In this work, a facile post-treatment of the as-extruded cable, including thermal and electrical treatment to produce high-density polyethylene (HDPE)/carbon black (CB) cable with excellent PTC effect, is developed. It is found for the as-extruded sample, the strong shearing makes the CB particles disperse uniformly in HDPE matrix, and 25 wt% CB is needed for the formation of conductive paths. For the thermal-treated sample, a gradually aggregated CB filler structure is observed, which leads to the improvement of PTC effect and the notable reduction of CB content to 20 wt%. It is very interesting to see that for the sample with combined thermal and electrical treatment, CB particles are agglomerated and oriented along the electric field direction to create substantial conductive paths, which leads to a further decrease of CB content down to 15 wt%. In this way, self-limiting heating cables with excellent processability, mechanical properties and PTC effect have simultaneously been achieved.

关键词： Self-limiting heating cables Positive temperature coefficient Thermal treatment Electrical treatment

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涡旋压缩机浮动式静盘的性能优化研究

压缩机技术 2024年第2期 12-16页

作者：刘兴旺李登辉刘晓明李远航蒋强强陈荣道兰州理工大学石油化工学院甘肃兰州730050 压缩机技术国家重点实验室(压缩机技术安徽省实验室) 安徽合肥230031

针对浮动式静盘涡旋压缩机静盘背部温度过高且集中于排气管处的问题,提出带散热结构的浮动式静盘背压机构,研究了新机构的质能交换,分析了热量交换过程,给出了各腔体传热的数学模型,并对新机构进行CFD模拟计算,得到了不同外界温度下的... 详细信息

针对浮动式静盘涡旋压缩机静盘背部温度过高且集中于排气管处的问题,提出带散热结构的浮动式静盘背压机构,研究了新机构的质能交换,分析了热量交换过程,给出了各腔体传热的数学模型,并对新机构进行CFD模拟计算,得到了不同外界温度下的静盘背部温度分布情况。与原浮动式静盘背压机构对比分析可得,新机构有效地改善了静盘背部中心温度过高的问题,使静盘温度分布更加均匀,可以解决因温度过高而造成的变形、摩擦磨损以及泄漏等问题,提高了压缩机的可靠性。

关键词：浮动式静盘质能交换数值模拟对流传热

Cytotoxic Cycloartane Triterpenoid Saponins from the Rhizomes of Cimicifuga foetida

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Natural Products and Bioprospecting 2019年第4期9卷 303-310页

作者： Jing Lu Xing‑Rong Peng Da‑Shan Li qiang‑qiang Shi Ming‑Hua Qiu State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of BotanyChinese Academy of Sciences(CAS)Kunming 650204People’s Republic of China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of BotanyChinese Academy of Sciences132 LanHei RoadKunming 650201YunnanPeople’s Republic of China

To enrich the bioactive cycloartane triterpenoid glycoside named actein and find out more cytotoxic cycloartane triterpenes,a phytochemical study of Cimicifuga foetida was conducted.113 g(0.17%)actein was purified by recrystallization while eight cycloartane-type triterpenes(1-8)were isolated from the mother *** chemical structures of new compounds(1-4)were elucidated by 1D and 2D NMR and HRESIMS spectroscopic ***,new compounds showed moderate and broad-spectrum cytotoxicity against 5 human cancer cell lines with IC_(50) values ranging from 4.02 to 15.80μM.

关键词： Cimicifuga foetida Cycloartane triterpenoid saponins Cytotoxic activity

Highly efficient oxidation of alcohols using Oxone~ as oxidant catalyzed by ruthenium complex under mild reaction conditions

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Chinese Chemical Letters 2008年第9期19卷 1031-1034页

作者： Zi qiang Lei Jian qiang Wang Peng Hua Yan Key Laboratory of Polymer Materials of Gansu Province College of Chemistry and Chemical Engineering Northwest Normal University Lanzhou 730070 China

Aromatic and alkyl alcohols were oxidized to the corresponding aldehydes or ketones at room temperature with high conversion and selectivity using Oxone （2KHSOs-KHSO4.K2SO4） as oxidant catalyzed by ruthenium complex Quin-Ru-Quin （where Quin = 8-hydroxyquinoline）. The reaction time is very short and the preparation of complex is simple.

关键词： Oxidation of alcohols Oxone Ruthenium complex

Continuous Orbit Equivalence of Semigroup Actions

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Acta Mathematica Sinica,English Series 2024年第6期40卷 1581-1598页

作者： Xiang Qi qiang Cheng Jun HOU School of Mathematical Science Yangzhou UniversityYangzhou 225002P.R.China

We introduce notions of continuous orbit equivalence and its one-sided version for countable left Ore semigroup actions on compact spaces by surjective local homeomorphisms,and characterize them in terms of the corresponding transformation groupoids and their operator *** particular,we show that two essentially free semigroup actions on totally disconnected compact spaces are continuously orbit equivalent if and only if there is a canonical abelian subalgebra preserving C^(∗)-isomorphism between the associated transformation groupoid C^(∗)-*** also give some examples of orbit equivalence,consider the special case of semigroup actions by homeomorphisms and relate continuous orbit equivalence of semigroup actions to that of the associated group actions.

关键词： Semigroup action continuous one-sided orbit equivalence continuous orbit equivalence groupoid C^(∗)-algebras

Efficiently simulating the work distribution of multiple identical bosons with boson sampling

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Frontiers of physics 2024年第3期19卷 197-206页

作者： Wen-qiang Liu Zhang-qi Yin Center for Quantum Technology Research and Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements(MOE) School of PhysicsBeijing Institute of TechnologyBeijing 100081China

Boson sampling has been theoretically proposed and experimentally demonstrated to show quantum computational ***,it still lacks the deep understanding of the practical applications of boson *** we propose that boson sampling can be used to efficiently simulate the work distribution of multiple identical *** link the work distribution to boson sampling and numerically calculate the transition amplitude matrix between the single-boson eigenstates in a one-dimensional quantum piston system,and then map the matrix to a linear optical network of boson *** work distribution can be efficiently simulated by the output probabilities of boson sampling using the method of the grouped probability *** scheme requires at most a polynomial number of the samples and the optical *** work opens up a new path towards the calculation of complex quantum work distribution using only photons and linear optics.

关键词： quantum simulation quantum work distribution boson sampling linear optic

Multicolored Bipartite Ramsey Numbers of Large Cycles

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 347-357页

作者： Shao-qiang LIU Yue-jian PENG College of Mathematics and Statistics Hanshan Normal UniversityChaozhou 521041China School of Mathematics Hunan UniversityChangsha 410082China

For an integer r≥2 and bipartite graphs Hi,where 1≤i≤r,the bipartite Ramsey number br(H1,H2,…,Hr)is the minimum integer N such that any r-edge coloring of the complete bipartite graph KN;N contains a monochromatic subgraph isomorphic to Hi in color i for some 1≤i≤*** show that if r≥3;α1,α2>0,αj+2≥[(j+2)!-1]Σi=1^(j+1)α1 for j=1,2…r-2,then br(C2[α1n],C2[α2n],…,C2[αrn]=(Σ=j=1^(r)a j+o(1))n.

关键词： ramsey number bipartite ramsey number regularity lemma