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Multistate Degradation Model for Prognostics of Solder Joints Under Vibration Conditions

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Chinese Journal of Electronics 2016年第4期25卷 779-785页

作者： TANG Wei JING Bo huang Yifeng SHENG Zengjin jiao Xiaoxuan Aeronautics and Astronautics Engineering College Air Force Engineering University

This paper develops a multistate degradation structure of the solder joints which can be used under various vibration conditions based on nonhomogeneous continuous-time hidden semi-Markov *** parameters of the structure were estimated to illustrate the stochastic relationship between the degradation process and the monitoring indicator by using unsupervised learning *** vibration tests on solder joints with different levels of power spectral density and fixed forms were conducted with a real time monitoring electrical resistance to examine the suitability of the *** was experimentally verified that the multistate degradation structure matches the experimental process reasonably and *** on this multistate degradation model,the online prognostics of solder joint were analyzed and the results indicated that faults or failures can be detected timely,leading to appreciate maintenance actions scheduled to avoid catastrophic failures of electronics.

关键词： Multistate degradation Prognostics Solder joint Vibration loading

Cu/Co/Cr Nanocomposites Obtained from Hydrotalcite Precursors as Catalysts for Thermal Decomposition of Ammonium Perchlorate

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Acta Metallurgica Sinica(English Letters) 2014年第2期27卷 211-216页

作者： Hongbo Liu Zhiyong huang Bingzhi Guo Qingze jiao Zhiyong Xiong School of Chemical Engineering and Materials Science Beijing Institute of Technology Zhuhai School of Chemical Engineering and Environment Beijing Institute of Technology College of Light Industry and Food Sciences South China University of Technology

A series of Cu/Co/Cr nanocomposites with different Cu/Co/Cr molar ratios were obtained by calcination of Cu/ Co/Cr hydrotalcites precursors, which were prepared by a co-precipitation reaction. X-ray diffraction, inductively coupled plasma analysis, and transmission electron microscopy were used to characterize the structure, composition, and mor- phology of Cu/Co/Cr nanocomposites. The results show that Cu/Co/Cr nanocomposites have both CuCr204 and CoCr204 spinel phase. The particle size of Cu/Co/Cr nanocomposites is 15-20 nm and the specific surface area is 95-115 m2/g. Cu/ Co/Cr nanocomposites were used as new catalysts for improving thermal decomposition of ammonium perchlorate （AP）. Their catalytic activities were investigated using differential thermal analysis and thermal gravimetric analyzer coupled with an online mass spectrometer. The results show that the decomposition temperature of AP lowered 132-146℃ by adding 4 wt% Cu/Co/Cr nanocomposites. Catalytic activities of the prepared nanocomposites depend on the calcinations temperature and addition amount of corresponding nanocomposites. The possible catalytic mechanism of Cu/Co/Cr nanocomposites was also studied and discussed.

关键词： Nanocomposite Thermal decomposition Catalytic activities 1

Fluorescence enhancement and cofluorescence in complexes of terbium(III) with trimellitic acid

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Rare Metals 2006年第2期25卷 144-149页

作者： ZHAO Xuehui huang Kelong jiao Feipeng LI Zhiaojian PENG Xiahui College of Chemistry and Chemical Engineering Central South University Changsha 410083 China Chemistry Department Hunan Technology and Science University Zhuzhou 412007 China

The fluorescence of terbium （Ⅲ） was enhanced by about three orders of magnitude in the presence of trimellitic acid （benzene-1, 2, 4-tricarboxylic acid （TLA）） in aqueous solution at pH 6. The fluorescence intensity could be greatly increased when the system of Tb^3＋-TLA was treated with La^3＋（or Gd^3＋） and TritonX- 100. The addition of La^3＋（or Gd^3＋） enhanees the fluorescence of the system by about two orders of magnitude due to cofluorescenee, and the TritonX-100 micellar medium plays an important role for stabilization of the system. Both the intermolecular energy transfer mode and intramolecular energy transfer mode are responsible for the mechanism of fluorescence enhancement. In the optimum condi- tions, the fluorescence intensity is a linear function of Tb3~ concentration in the range of 7.8 × 10^-9-3.6 × 10^4 mol/L for the system Tb^3＋-La^3＋-TLA and 1.0 × 10^-8-4.7 × 10^-5 mol/L for the system Tb^3＋-Gd^3＋-TLA, and the limits of detection are 4.6 × 10^-10 mol/L and 6.0 × 10^-10 mol/L, respectively.

关键词： analytical chemistry fluorescence enhancement spectrofluorimetry trimellitic acid terbium cofluorescence

An improved three-dimensional spherical DDA model for simulating rock failure

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Science China(Technological Sciences) 2015年第9期58卷 1533-1541页

作者： jiao YuYong huang GangHai ZHAO ZhiYe ZHENG Fei WANG Long State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences School of Civil and Environmental Engineering Nanyang Technological University

In this paper, a discontinuous numerical model, namely SDDARF3D(three-dimensional spherical discontinuous deformation analysis for rock failure), is proposed for simulating the whole process of rock failure. Firstly, within the framework of the classical discontinuous deformation analysis(DDA) method, the formulation of three-dimensional spherical DDA(3D SDDA) is deduced; secondly, a bonding and cracking algorithm is constructed and the SDDARF3 D model is proposed; thirdly, corresponding VC++ calculation code is developed and some verification examples are calculated. The simulated results can intuitively reproduce the failure phenomena of rock mass, indicating that the proposed SDDARF3 D numerical model is correct and effective.

关键词： rock failure three-dimensional spherical discontinuous deformation analysis crack propagation bonding and cracking algorithm

固相萃取⁃高效液相色谱⁃三重四极杆质谱法分析饮用水处理厂水样中7种香豆素

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色谱 2025年第1期43卷 78-86页

作者：矫文美杨晶铭徐策高福康沈璐瑶元宇博郭志芬黄光江苏第二师范学院生命科学与化学化工学院江苏南京211200 南京医科大学口腔医学院江苏南京210029 南京医科大学公共卫生学院江苏南京211166 南京医科大学公共卫生学院现代毒理学教育部重点实验室江苏南京211166

本研究建立了一种固相萃取结合高效液相色谱-三重四极杆质谱法分析饮用水处理厂水样中7种香豆素类化合物的方法。样品前处理过程采用HLB小柱进行固相萃取,然后采用超纯水(含025%甲酸)淋洗,最后经甲醇(含025%甲酸)洗脱。萃取液用Phenomen... 详细信息

本研究建立了一种固相萃取结合高效液相色谱-三重四极杆质谱法分析饮用水处理厂水样中7种香豆素类化合物的方法。样品前处理过程采用HLB小柱进行固相萃取,然后采用超纯水(含025%甲酸)淋洗,最后经甲醇(含025%甲酸)洗脱。萃取液用Phenomenex Luna C18柱(100 mm×20 mm,3μm)分离后,以甲醇-01%甲酸水溶液为流动相进行梯度洗脱,在电喷雾多反应监测模式下检测。以饮用水原水和出厂水为基质考察方法的基质效应、精密度和准确度。7种香豆素类化合物在各自的线性范围内呈现良好的线性关系,相关系数(r)均大于099,方法检出限(MDL)为067~112 ng/L。不同加标水平(20、50、100 ng/L)下7种香豆素类化合物回收率为614%~915%,相对标准偏差(RSD,n=6)均≤112%。利用该方法分析了饮用水处理厂不同处理阶段的水样,其中7-羟基香豆素、6,7-二羟基香豆素、香豆素的检出率为100%,含量为021~279 ng/L。6-羟基-4-甲基香豆素在原水、混凝后水样、炭滤后水样中均未检出,只在砂滤后水样和出厂水中被检出,而且出厂水中的含量(469 ng/L)高于砂滤后水样(179 ng/L)。8-氯-7-羟基香豆素只在出厂水中被检出(028 ng/L)。本方法分析时间短,精密度和准确度良好,在监测实际水样中香豆素的含量及评估饮用水处理过程对于水样中香豆素类化合物去除方面可发挥积极作用。

关键词：固相萃取高效液相色谱-串联质谱法饮用水香豆素消毒副产物

A real-time multi-head mixed attention mechanism-based prediction method for tunnel boring machine disc cutter wear

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Science China(Technological Sciences) 2025年第1期68卷 286-307页

作者： Haodi WANG Chengjin QIN Honggan YU Zhinan ZHANG Guoqiang huang Zhengyang LIU Chengliang LIU State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

In the process of hard rock tunnel excavation,workers often need to enter the tunnel boring machine(TBM)cutterhead at regular intervals to measure cutter ***,this method is time-consuming and *** cutter prediction models primarily rely on geological parameters to predict overall cutter wear before construction,making it challenging to monitor real-time wear at different locations of the cutter and obtain accurate geological *** address these challenges,this paper proposes a multi-head mixed attention mechanism-based method for real-time wear prediction of TBM disc ***,a method of cutter wear normalization to eliminate measurement noise is ***,considering the complex correlation of TBM operating parameters in feature and time dimensions,a new multi-head mixed attention mechanism model is designed to establish the dependency between different features and different moments,to better establish the mapping model between operating parameters and cutter ***,the current cutter wear state can be calculated by accumulating the wear amount of all previous small excavation *** effectiveness of the method is verified by using field data from the Mumbai *** results demonstrate that the method is capable of real-time prediction of front cutter and edge cutter wear on the test set,achieving an average accuracy rate of 95.75%.Moreover,the method can update the cutter wear status after every meter of excavation,which has good real-time *** addition,the average accuracy of cutter wear prediction of the proposed method is 11.75%,10.375%,3.875%,3.625%,1.375%,3.125%,2.25%,and 0.75%higher than that of LSTM,CNN,LSTM-CNN,CACNN,SACNN,MMADNN,MTACNN,and *** summary,this approach offers an accurate prediction of cutter wear state while reducing inspection time and costs and has high application value.

关键词： tunnel boring machine cutter wear estimation multi-head mixed attention mechanism real time

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Waterproof Perovskite Quantum Dots for In-vivo Photoluminescence Bioimaging

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Chemical Research in Chinese Universities 2024年第5期40卷 901-906页

作者： jiao Ziyue WANG Xinli GAO Jie huang Xiao WANG Yi Key Laboratory of Advanced Light Conversion Materials and Biophotonics School of Chemistry and Life ResourcesRenmin University of ChinaBeijing100872P.R.China

Perovskite quantum dots(PQDs)have demonstrated great promise in bioimaging applications owing to their outstanding photophysical ***,their practicality is seriously limited by the instability of PQDs against *** we develop a post-synthetic ligand exchange strategy to construct silica-coated PQD(PQD@SiO_(2))nanocrystals,which results in the simultaneous improvement of photoluminescence efficiency and moisture *** importantly,compared to the classical in-situ ligand exchange method of fabricating PQD@SiO_(2),the issues of chemical etching and resultant photoluminescence degradation are judiciously *** the proposed PQD@SiO_(2),we showcase their robust usefulness in labeling chlorella,paving the way for PQD-based in-vivo photoluminescence bioimaging methodology.

关键词： Perovskite Quantum dot Photoluminescence Stability Bioimaging

Patterns and drivers of seasonal water sources for artificial sand-fixing plants in the northeastern Mu Us sandy land,Northwest China

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Pedosphere 2024年第1期34卷 63-77页

作者： Yanwu PEI Laiming huang Ming'an SHAO jiao WANG Yinglong ZHANG Yellow River Delta Modern Agricultural Engineering Laboratory Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Natural Resources and Environment Northwest Agriculture and Forestry UniversityYangling 712100China State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences of Chinese Academy of SciencesBeijing 100085China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Shenmu Ecological Association Shenmu 719399China

Understanding plant water-use patterns is important for improving water-use efficiency and for sustainable vegetation restoration in arid and semi-arid regions. However, seasonal variations in water sources and their control by different sand-fixing plants in water-limited desert ecosystems remain poorly understood. In this study, stable isotopic ratios of hydrogen(δ^(2)H) and oxygen(δ^(18)O) in precipitation, soil water, groundwater, and xylem water were determined to document seasonal changes in water uptake by three representative plant species(Pinus sylvestris var. mongolica Litv., Amygdalus pedunculata Pall., and Salix psammophila) in the northeastern Mu Us sandy land, Northwest China. Based on the depth distribution and temporal variation of measured gravimetric soil water content(SWC), the soil water profile of the three species stands was divided into active(0.01 g g^(-1)tion(CV) 45%) layers. Annually, P. sylvestris, A. pedunculata, and S. psammophila obtained most water from deep(59.2%±9.7%, moist layer and groundwater),intermediate(57.4%±9.8%, stable and moist layers), and shallow(54.4%±10.5%, active and stable layers) sources, respectively. Seasonally, the three plant species absorbed more than 60% of their total water uptake from the moist layer and groundwater in the early(June) dry season;then, they switched to the active and stable layers in the rainy season(July–September) for water resources(50.1%–62.5%). In the late(October–November) dry season, P. sylvestris(54.5%–66.2%) and A. pedunculata(52.9%–63.6%) mainly used water from stable and moist layers, whereas S. psammophila(52.6%–70.7%) still extracted water predominantly from active and stable layers. Variations in the soil water profile induced by seasonal fluctuations in precipitation and groundwater levels and discrepancies in plant pheno

关键词： desert ecosystem MixSIAR model plant water uptake soil moisture stable isotopes vegetation restoration water-use efficiency

Dynamic thermal coupling modeling and analysis of wet electro-hydrostatic actuator

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Chinese Journal of Aeronautics 2022年第6期35卷 298-311页

作者： Zongxia jiao Yanpeng LI tian YU Chaofan JIANG Ligang huang Yaoxing SHANG School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100083China Science and Technology on Aircraft Control Laboratory Beihang UniversityBeijing 100083China Research Institute for Frontier Science Beihang University100083 BeijingChina Ningbo Institute of Technology Beihang UniversityNingbo 315800China

The electro-hydrostatic actuator(EHA)used in more electric aircraft(MEA)has been extensively studied due to its advantages of high reliability and high ***,this high integration results in a small heat dissipation area,leading to high-temperature ***,to reduce the temperature,a wet cooling method of using the pump leakage oil to cool the motor is adopted,which can also increase the difficulty of accurately predicting the system temperature in the early design *** solve this problem,a dynamic coupling thermal model of a wet EHA is proposed in this *** particular,the leakage oil of the pump is used as a coupling item between the electrical system and the hydraulic ***,an improved T-equivalent block model is proposed to address the uneven distribution of axial oil temperature inside the motor,and the control node method is applied to hydraulic system thermal ***,a dynamic coupling thermal model is developed that enables a dynamic evaluation of the wet EHA ***,experimental prototypes of wet motor and wet EHA are developed,while the temperature response of the wet motor at different rotation speeds and different loads and the temperature response of the wet EHA at no-load condition were verified experimentally at room temperature,*** maximum temperature difference between the experimental and theoretical results of the wet motor as well as the experimental and theoretical results of the wet EHA is less than 8℃.These test results indicate that the dynamic coupling thermal model is valid and demonstrate that the thermal coupling modeling method proposed in this paper can provide a basis for the detailed thermal design of EHA.

关键词： Electro-hydrostatic actuator Hydraulic More electric aircraft Thermal mode Wet motor