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A new vibration mechanism of balancing machine for satellite-borne spinning rotors

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Chinese Journal of Aeronautics 2014年第5期27卷 1318-1326页

作者： wang Qiuxiao wang fei College of Mechanical Engineering Chongqing University

The centrifugal force and overturning moment generated by satellite-borne rotating payload have a significant impact on the stability of on-orbit satellite attitude, which must be controlled to the qualified range. For the satellite-borne rotors＇ low working revs and large centroidal deviation and height, and that the horizontal vibration produced by centrifugal force is not of the same magnitude as the torsional vibration by overturning moment, the balancing machine＇s measurement accuracy is low. Analysis shows that the mixture of horizontal vibration and torsional vibration of the vibrational mechanism contribute mainly to the machine＇s performance, as well as the instability of vibration center position. A vibrational mechanism was put forward, in which the horizontal and torsional vibration get separated effectively by way of fixing the vibration center. From experimental results, the separation between the weak centrifugal force signal and the strong moment signal was realized, errors caused by unstable vibration center are avoided, and the balancing machine based on this vibration structure is able to meet the requirements of dynamic balancing for the satellite＇s rotating payloads in terms of accuracy and stability.

关键词： Rotational unbalance Satellite-borne rotor Separation of static unbalance and couple unbalance Vertical balancing machine Vibration measurement

Role of oxygen vacancy inducer for graphene in graphene-containing anodes

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Frontiers of Chemical Science and Engineering 2023年第3期17卷 326-333页

作者： fei wang Jian Mao College of Materials Science and Engineering Sichuan UniversityChengdu 610065China

Currently,graphene is only considered as a conductive additive and expansion inhibitor in oxides/graphene composite *** this study,a new graphene role(oxygen vacancy inducer)in graphene/oxides composites anodes,which are treated at high-temperature,is proposed and verified using experiments and density functional theory *** high-temperature processing,graphene forms carbon vacancies due to increased thermal vibration,and the carbon vacancies capture oxygen atoms,facilitating the formation of oxygen vacancies in ***,the induced oxygen vacancy concentrations can be regulated by sintering temperatures,and the behavior is unaffected by oxide crystal structures(crystalline and amorphous)and morphology(size and shape).According to density functional theory calculations and electrochemical measurements,the oxygen vacancies enhance the lithiumion storage *** findings can result in a better understanding of graphene’s roles in graphene/oxide composite anodes,and provide a new method for designing high-performance oxide anodes.

关键词： oxide oxygen vacancy graphene anode density functional theory calculation

HAS Dynamic Buffer-Driven Resource Management to Enhance QoE in Mobile Network

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China Communications 2017年第7期14卷 11-24页

作者： fei wang Zesong fei Jing wang School of Information and Electronics Beijing Institute of Technology

Hypertext transfer protocol(HTTP) adaptive streaming(HAS) plays a key role in mobile video transmission. Considering the multi-segment and multi-rate features of HAS, this paper proposes a buffer-driven resource management(BDRM) method to enhance HAS quality of experience(QoE) in mobile network. Different from the traditional methods only focusing on base station side without considering the buffer, the proposed method takes both station and client sides into account and end user's buffer plays as the drive of whole schedule process. The proposed HAS QoE influencing factors are composed of initial delay, rebuffering and quality level. The BDRM method decomposes the HAS QoE maximization problem into client and base station sides separately to solve it in multicell and multi-user video playing scene in mobile network. In client side, the decision is made based on buffer probe and rate request algorithm by each user separately. It guarantees the less rebuffering events and decides which HAS segment rate to fetch. While, in the base station side, the schedule of wireless resource is made to maximize the quality level of all access clients and decides the final rate pulled from HAS server. The drive of buffer and twice rate request schemes make BDRMtake full advantage of HAS's multi-segment and multi-rate features. As to the simulation results, compared with proportional fair(PF), Max C/I and traditional HAS schedule(THS) methods, the proposed BDRM method decreases rebuffering percent to 1.96% from 11.1% with PF and from 7.01% with THS and increases the mean MOS of all users to 3.94 from 3.42 with PF method and from 2.15 with Max C/I method. It also guarantees a high fairness with 0.98 from the view of objective and subjective assessment metrics.

关键词： resource management Hypertexl transfer protocol (HTTP) adaptive streaming (HAS) buffer rate request quality of experience (QoE) mobile network

Empirical evidence for estimation of subsurface settlement caused by tunneling in sand

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Underground Space 2021年第5期6卷 577-584页

作者： fei wang School of Engineering Tarleton State University1333W.Washington StreetStephenvilleTX 76402USA

Tunneling is vital for augmenting urban infrastructure systems in big ***,the ground movement or settlement induced by tunneling can cause significant damage to the surrounding buildings,bridges,roadways,pipelines,and so *** theoretical and empirical methods have been proposed to estimate the settlement trough at the ground surface caused by *** settlement caused by tunneling in clay has been investigated extensively to evaluate the safety of pipelines and foundations above tunnels based on the assumption of a constant volume of the settlement trough along the ***,subsurface settlement induced by tunneling in sand has not been understood well due to the change of volume of settlement trough along the *** though an empirical method was developed by the author based on lab-scale model test results,it has not been validated using observational data from case *** this study,three case histories from the literature were used to verify the effectiveness of the aforementioned empirical method for estimating the subsurface settlement caused by tunneling in *** comparison of the calculated results and measurements from the case histories demonstrates that the empirical method is effective to predict the subsurface settlement caused by tunneling in sand.

关键词： Tunneling Subsurface settlement Case histories Sand

Quantitative evaluation of gas hydrate reservoir by AVO attributes analysis based on the Brekhovskikh equation

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Petroleum Science 2023年第4期20卷 2045-2059页

作者： Yao wang Yan-fei wang Key Laboratory of Petroleum Resources Research Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China University of Chinese Academy of Sciences Beijing100049China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing100029China

AVO (Amplitude variation with offset) technology is widely used in gas hydrate research. BSR (Bottom simulating reflector), caused by the huge difference in wave impedance between the hydrate reservoir and the underlying free gas reservoir, is the bottom boundary mark of the hydrate reservoir. Analyzing the AVO attributes of BSR can evaluate hydrate reservoirs. However, the Zoeppritz equation which is the theoretical basis of conventional AVO technology has inherent problems: the Zoeppritz equation does not consider the influence of thin layer thickness on reflection coefficients;the approximation of the Zoeppritz equation assumes that the difference of wave impedance between the two sides of the interface is small. These assumptions are not consistent with the occurrence characteristics of natural gas hydrate. The Brekhovskikh equation, which is more suitable for thin-layer reflection coefficient calculation, is used as the theoretical basis for AVO analysis. The reflection coefficients calculated by the Brekhovskikh equation are complex numbers with phase angles. Therefore, attributes of the reflection coefficient and its phase angle changing with offset are used to analyze the hydrate reservoir's porosity, saturation, and thickness. Finally, the random forest algorithm is used to predict the reservoir porosity, hydrate saturation, and thickness of the hydrate reservoir. In the synthetic data, the inversion results based on the four attributes of the Brekhovskikh equation are better than the conventional inversion results based on the two attributes of Zoeppritz, and the thickness can be accurately predicted. The proposed method also achieves good results in the application of Blake Ridge data. According to the method proposed in this paper, the hydrate reservoir in the area has a high porosity (more than 50%), and a medium saturation (between 10% and 20%). The thickness is mainly between 200m and 300m. It is consistent with the previous results obtained by veloci

关键词： Natural gas hydrate Brekhovskikh equation AVO attributes Random forest

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释“■(免)”

三峡大学学报（人文社会科学版） 2025年第1期47卷 108-115页

作者：程邦雄杨灿王斐三峡大学文学与传媒学院湖北宜昌43002 华中科技大学中国语言研究所湖北武汉430074 华中师范大学文学院湖北武汉430079

甲骨文“■”等形体,孙诒让最早在《契文举例·释文字》里,进行了分析讨论,正误参半。“■”等字,在卜辞里意义多是“分娩”,但是从文字角度看,应隶定为何字,学界讨论甚多,意见不一。结合传世文献与最新的出土文献,从“■”的构形、上... 详细信息

甲骨文“■”等形体,孙诒让最早在《契文举例·释文字》里,进行了分析讨论,正误参半。“■”等字,在卜辞里意义多是“分娩”,但是从文字角度看,应隶定为何字,学界讨论甚多,意见不一。结合传世文献与最新的出土文献,从“■”的构形、上下文语境、涉及的句式语法、语义搭配、字词关系等多角度观察、分析,“■”等甲骨文形体应隶释为“免”字,记录的是“分娩”义的{免},而不应该隶为“娩”字,以记录“分娩”义的{娩}。《说文》不收单字“免”,是遗漏,“分娩”义的“免”字非后出,《说文》收有含声符和义符“免”的合体字多例,并单独立有“儿部”,金文、战国(楚)简帛也有从“子”或从“儿(■)”的“免”字。郑珍释“免,子脱胞也。从二儿:上儿,母也;下儿,子也”,其说有据。

关键词： ■ 免 {免} 娩

A tendon system to re-center steel moment frames with weak stories

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Earthquake Engineering and Engineering Vibration 2024年第4期23卷 1057-1072页

作者： wang Tao wang fei Masayoshi Nakashima Institute of Engineering Mechanics China Earthquake AdministrationBeijing 100190China Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering MechanicsChina Earthquake AdministrationHarbin 150080China Disaster Prevention Research Institute Kyoto UniversityGokashoUjiKyoto 611-0011Japan

A wide open bottom story of a frame building is often expected by owners for use as a garage or ***,this leads to weak stories due to abrupt changes in lateral stiffness and often results in unexpected story collapse as observed in many previous *** retrofit frame buildings that have experienced weak story damage,a tendon system is proposed in this study,which consists of a set of swaying columns and *** swaying columns are used to uniformly redistribute the lateral deformation along the height,while the tendons provide extra lateral stiffness and renders the entire structural system a re-centering *** avoid unnecessary forces to swaying columns,pin-connections are used at the *** are placed over the entire story to gain large elastic *** analysis reveals that the swaying column,with a stiffness of about 0.9 times that of the weak story,and the tendons attached at the roof,with a stiffness of 0.04 times that of the weak story,can provide the optimal performance with a maximum residual story drift angle of less than 0.5%.Online hybrid tests were carried out,which demonstrated that uniformly distributed story drifts and acceptable residual deformation could be achieved by the proposed tendon system.

关键词： tendon system re-centering capability residual deformation rehabilitation collapse prevention

HAS QoE prediction based on dynamic video features with data mining in LTE network

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Science China(Information Sciences) 2017年第4期60卷 196-209页

作者： fei wang Zesong fei Jing wang Yifan LIU Zhikun WU School of Information Science and Engineering Beijing Institute of Technology

Evaluation of HTTP adaptive streaming(HAS) quality of experience(Qo E) over LTE network is a challenging topic because of multi-segment and multi-rate features of dynamic video sequences. Different from the traditional Qo E evaluation methods based on network parameters, this paper proposes the HAS Qo E prediction methods based on its dynamic video segment features with data mining. Considering the application requirement of the trade-off between accuracy and complexity, two sets of methodologies are designed to evaluate the HAS Qo E including regression and classification. In regression method, we propose the evolved PSNR(e PSNR) model using differential peak signal to noise ratio(d PSNR) statistics as the segment features to evaluate HAS Qo E. In classification method, we propose the improved weighted k-nearest neighbors(Wk NN)by using dynamic weighted mapping according to the position of video chunk to meet the dynamic segment and rate features of HAS. In order to train and test these methods, we build a real-time HAS video-on-demand(VOD) system in LTE network and do subjective test in different video scenes. With the mean opinion score(MOS), the regression and classification methods are trained to predict the HAS Qo E. The validated results show that the proposed e PSNR and Wk NN methods outperform other evaluation methods.

关键词： HTTP adaptive streaming(HAS) quality of experience(Qo E) regression classification data mining video-on-demand(VOD) long term evolution(LTE)

Fabrication of nickel oxide functionalized zeolite USY composite as a promising adsorbent for CO_(2) capture

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Chinese Journal of Chemical Engineering 2022年第6期35卷 207-213页

作者： Jipeng Dong fei wang Guanghui Chen Shougui wang Cailin Ji fei Gao Shandong Key Laboratory of Multiphase Fluid Reaction and Separation Engineering College of Chemical EngineeringQingdao University of Science and TechnologyQingdao 266042China Department of Chemical Engineering Qingdao University of Science and TechnologyGaomi 261500China

Adsorption process is considered to be the most promising alternative for the CO_(2) capture to the traditional energy-intensive amine absorption process,and the development of feasible and efficient CO_(2) adsorbents is still a *** this work,the NiO@USY(ultrastable Y)composites with different NiO loadings were prepared for the CO_(2) adsorption using Ni(NO_(3))_(2) as the *** composites were characterized by X-ray photoelectron spectroscopy,X-ray diffraction,nitrogen adsorption–desorption test,scanning electron microscopy analysis,and thermogravimetric analysis,and were evaluated for the CO_(2) adsorption capacity,CO_(2)/N2 adsorption selectivity and CO_(2) cycle adsorption *** characterization results show that after the activation at 423 K,the Ni(NO_(3))_(2) species were well dispersed into the surface of zeolite USY,and after the further activation at 823 K,Ni(NO_(3))_(2) could be converted into highly dispersed *** adsorption results show that the presence of the active component NiO plays an important role in improving the CO_(2) adsorption performance,and the NiO@USY composite with a NiO loading of 1.5 mmol·g^(-1) USY support displays a high adsorption capacity and adsorption selectivity for CO_(2),and shows a good cycle *** addition,the Clausius–Clapeyron equation was used to evaluate the isosteric heat of adsorption of CO_(2) on the NiO(1.5)@USY composite,and the heat of adsorption was 17.39–38.34 kJ·mol^(-1).

关键词： NiO@USY composites Carbon dioxide Adsorption Separation Adsorption selectivity