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Position-varying surface roughness prediction method considering compensated acceleration in milling of thin-walled workpiece

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Frontiers of Mechanical Engineering 2021年第4期16卷 855-867页

作者： Zequan YAO Chang fan Zhao ZHANG Dinghua ZHANG Ming LUO Key Laboratory of High Performance Manufacturing for Aero Engine(Ministry of Industry and Information Technology) Northwestern Polytechnical UniversityXi'an 710072China Engineering Research Center of Advanced Manufacturing Technology for Aero Engine(Ministry of Education) Northwestern Polytechnical UniversityXi'an 710072China

Machined surface roughness will affect parts?service ***,predicting it in the machining is important to avoid *** roughness will be affected by system position dependent vibration even under constant parameter with certain toolpath processing in the *** at surface roughness prediction in the machining process,this paper proposes a position-varying surface roughness prediction method based on compensated acceleration by using regression *** reduce the stochastic error of measuring the machined surface profile height,the surface area is repeatedly measured three times,and Pauta criterion is adopted to eliminate abnormal *** actual vibration state at any processing position is obtained through the single-point monitoring acceleration compensation *** acceleration features are extracted,and valley,which has the highest/^-square proving the effectiveness of the filtering features,is selected as the input of the prediction model by mutual information ***,by comparing the measured and predicted surface roughness curves,they have the same trends,with the average error of 16.28%and the minimum error of 0.16%.Moreover,the prediction curve matches and agrees well with the actual surface state,which verifies the accuracy and reliability of the model.

关键词： surface roughness prediction compensated acceleration milling thin-walled workpiece

Variations in the effective and bankfull discharge for suspended sediment transport due to dam construction

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Frontiers of Earth Science 2022年第2期16卷 446-464页

作者： fan CHEN Li CHEN Wei ZHANG Jing YUAN Kanghe ZHANG State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Changjiang Institute of Survey PlanningDesign and ResearchWuhan 430010China Bureau of Hydrology Changjiang Water Resources CommissionWuhan 430010China

A varied class method is applied to calculate the effective discharges and their variations after the Three Gorges Dam(TGD)construction based on the mean daily flow discharge and suspended sediment concentration field data from 1981 to *** comparison,the bankfull discharges are also determined according to the cross-section profiles and flow discharge-stage *** results show that a bimodal effective discharge curve usually exists at the fixed sites,which generates two effective discharges(Q_(e1) and Q_(e2))within the moderate flow *** the quasi-equilibrium circumstances of the pre-dam period,effective discharges are closely related to the mean annual runoff,with a narrow range of regional variations in occurrence *** analyses draw the conclusion that the relatively higher unsaturation degrees of the pre-dam effective discharges caused by dam interception and riverbed coarsening are the primary cause of the increase in effective discharges from Yichang to Shashi,while the more frequent low and medium discharges due to flow regulation drive the decrease in effective discharges from Jianli to *** slightly elevated flood levels and descending bankfull levels collaboratively result in the decrease of bankfull discharges from Yichang to Shashi,while the lowered bed elevation causes the increase in bankfull discharges from Luoshan to ***,the bankfull discharge in the Middle and Lower Yangtze River is larger than effective discharge and approaches the 1.5-year recurrence interval discharge.

关键词： effective discharge bankfull discharge unsaturation degree flow-sediment regimes Middle and Lower Yangtze River Three Gorges Dam

A novel method for telescope polarization modeling based on an artificial neural network

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Research in Astronomy and Astrophysics 2021年第7期21卷 41-50页

作者： Jian-Guo Peng Shu Yuan Kai-fan Ji Zhi Xu Yunnan Observatories Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China

The polarization characteristics of an astronomical telescope is an important factor that affects polarimetry accuracy. Polarization modeling is an essential means to achieve high precision and efficient polarization measurement of the telescope, especially for the alt-azimuth mount telescope. At present, the polarization model for the telescope(i.e., the physical parametric model) is mainly constructed using the polarization parameters of each optical element. In this paper, an artificial neural network(ANN) is used to model the polarization characteristics of the telescope. The ANN model between the physical parametric model residual and the pointing direction of the telescope is obtained, which reduces the model deviation caused by the incompleteness of the physical parametric model. Compared with the physical parametric model, the model fitting and predictive accuracy of the New Vacuum Solar Telescope(NVST) is improved after adopting the ANN model. After using the ANN model, the polarization cross-talk from I to Q, U, and V can be reduced from 0.011 to 0.007, and the crosstalk among Q, U, and V can be reduced from 0.047 to 0.020, which effectively improves the polarization measurement accuracy of the telescope.

关键词： techniques:polarimetric telescopes polarization instrumentation:polarimeters

Lateral earth pressure of granular backfills on retaining walls with expanded polystyrene geofoam inclusions under limited surcharge loading

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1388-1397页

作者： Kewei fan Guangqing Yang Weilie Zou Zhong Han Yang Shen Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing210098China School of Civil Engineering Wuhan UniversityWuhan430072China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang050043China

Existing studies have focused on the behavior of the retaining wall equipped with expanded polystyrene(EPS)geofoam inclusions under semi-infinite surcharge loading rather than limited surcharge *** this paper,the failure mode and the earth pressure acting on the rigid retaining wall with EPS geofoam inclusions and granular backfills(henceforth referred to as EPS-wall),under limited surcharge loading are investigated through two-and three-dimensional model *** testing results show that different from the sliding of almost all the backfill in the EPS-wall under semi-infinite surcharge loading,only an approximately triangular backfill slides in the wall under limited surcharge *** distribution of the lateral earth pressure on the EPS-wall under limited surcharge loading is non-linear,and the distribution changes from the increase of the wall depth to the decrease with the increase of the limited surcharge *** approach based on the force equilibrium of a differential element is developed to predict the lateral earth pressure behind the EPS-wall subjected to limited surcharge loading,and its performance was fully validated by the three-dimensional model tests.

关键词： Retaining wall Expanded polystyrene(EPS)geofoam Limited surcharge loading Lateral earth pressure Model test Prediction

Dynamic Travel Time Prediction Models for Buses Using Only GPS Data

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International Journal of Transportation Science and Technology 2015年第4期4卷 353-366页

作者： Wei fan Zegeye Gurmu Associate Professor Department of Civil and Environmental EngineeringThe University of North Carolina at CharlotteEPIC BuildingRoom 32619201 University City BoulevardCharlotteNC 28223 Traffic Engineer-Teague Nall&Perkins Inc.1100 Macon StreetFort WorthTexas 76102

Providing real-time and accurate travel time information of transit vehicles can be very helpful as it assists passengers in planning their trips to minimize waiting *** purpose of this research is to develop and compare dynamic travel time prediction models which can provide accurate prediction of bus travel time in order to give realtime information at a given downstream bus stop using only global positioning system(GPS)*** Average(HA),Kalman Filtering(KF)and Artificial Neural Network(ANN)models are considered and developed in this paper.A case has been studied by making use of the three *** results are obtained from the case study,indicating that the models can be used to implement an Advanced Public Transport *** implementation of this system could assist transit operators in improving the reliability of bus services,thus attracting more travelers to transit vehicles and helping relieve *** performances of the three models were assessed and compared with each other under two criteria:overall prediction accuracy and *** was shown that the ANN outperformed the other two models in both *** conclusion,it is shown that bus travel time information can be reasonably provided using only arrival and departure time information at stops even in the absence of traffic-stream data.

关键词： operators attracting conclusion

Erosion hotspot identified along the sandy coast of Shanwei: characteristics and origin

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Acta Oceanologica Sinica 2023年第7期42卷 91-102页

作者： Jitao Yu Yuanting Ding Lin Zhang Pei Liu Renfu fan Hainan Academy of Ocean and Fisheries Sciences Haikou 571126China Yazhou Bay Innovation Institute Hainan Tropical Ocean UniversitySanya 572025China School of Geography and Environmental Sciences Hainan Normal UniversityHaikou 571158China

Based on the measured beach profile data of Sanzhou Bay from 2015 to 2019,an erosion hotspot was identified along the Shanwei coastline of eastern Guangdong,where the maximum retreat distance of the shoreline exceeded 80 m and the erosion rate was more than 20 m/*** determine the time at which the erosion hotspot started and the potential causes of its formation,this study used 63 Landsat satellite images from 1986 to 2019 to construct a time series of shoreline positions over the past 30 years by extracting their high-tide ***,the M-K trend test method was introduced to evaluate the non-linear shoreline behavior based on the single-transect *** results showed that the time of approximately 2013 marked the start of the erosion hotspot,the erosion hotspot was characterized by erosion rates of more than 2 m/a(a maximum rate of 31.6 m/a),and the affected shoreline more than 4.3 km from 2013 to ***,this erosion hotspot was proved to be caused by artificial sand mining in the nearshore zone,which destroyed the original beach’s morphodynamic *** the aid of storm events,soil cliffs composed of loose sediment on the backshore were sacrificed to achieve a new equilibrium,resulting in an extremely significant retreat parallel to the coast on the west side of the study area,which reflects the combined effect of human and natural *** study provides a concrete example of the rapid response of shorelines to artificial sand mining activities,and the associated finding is a stark warning about the cautious development and utilization of coastal zones and the strict regulation of human activities.

关键词： erosion hotspot shoreline non-linear behavior artificial sand mining beach morphodynamic equilibrium Landsat images

Insight into the effect of gel drying temperature on the structure and desulfurization performance of ZnO/SiO_(2)adsorbents

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Chinese Journal of Chemical Engineering 2023年第4期56卷 233-241页

作者： Chao Yang Zhelin Su Yeshuang Wang Huiling fan Meisheng Liang Zhaohui Chen College of Environmental Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China State Key Laboratory of Clean and Efficient Coal Utilization Taiyuan University of TechnologyTaiyuan 030024China State Key Laboratory of Multi-phase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China

A series of ZnO/SiO_(2) adsorbents were prepared by a sol-gel method using tetraethyl orthosilicate,ethylene glycol(EG)and nitrates as *** effect of gel drying temperature on the structure and desulfurization performance of the adsorbents were investigated in *** is found that the low drying temperature led to a weak interaction among EG,Si AOH/H_(2)O and the nitrates in the gel system,which caused the oxidation of EG by NO3-and formed zinc glyoxylate complex during the gel calcination process,whereas this oxidation process also occurred at a high drying temperature during the gel drying *** formed zinc glyoxylate complex promoted the generation of monodentate carbonate on the surface of Zn O,which resulted in the inferior desulfurization performance of adsorbents despite they have smaller Zn O *** gel dried at 120°C formed the hydrogen bonds between EG and Si AOH/H_(2)O and a strong interaction between zinc oxo-clusters and NO3-was also found in the gel system,which avoided the oxidation of EG by NO3-during the preparation process and the Zn O nanoparticles with sizes of 6 nm were formed by a combustion *** adsorbent affords a highest sulfur capacity of 104.9 mg·g^(-1) in this *** addition,the gel drying temperature has a significant influence on the textural properties of the adsorbents except their surface area.

关键词： Sol-gel method Drying temperature H_(2)S removal Zinc-silica composites Hydrogen bonds

Motion Control of Capsule-like Underwater Robot Utilizing the Swing Properties of Ionic Polymer Metal Composite Actuators

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Journal of Bionic Engineering 2020年第2期17卷 281-289页

作者： Hongkai Li Min fan Yinghao Yue Guoliang Hu Qingsong He Min Yu Key Laboratory of Bionic Functional Materials of Jiangsu Province Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Science and Technology on Electro-optic Control Laboratory Luoyang 471000China

Ionic Polymer Metal Composite(IPMC)is a novel electrically actuated intelligent material with the advantages of big bending displacement,low driving voltage,flexible and so *** has been recognized as one of the most attractive actuators with prospective applications for underwater robots and bionic *** this work,a capsule-like robot was introduced with the pectoral and caudal fins made of *** analyzing the properties of displacement response to square waves with different frequencies and low level voltages,it was found that performance of IPMC are frequency ***,when the absolute value of low level voltage decreases,IPMC could swing on one side with the decrease in amplitudes,whereas the amplitude at high level voltage fluctuates within small ranges at low *** tip can approximately maintain when the frequency of driving signal around 30 *** properties were employed to control the locomotion of robot combining the motions of pectoral and caudal ***,the locomotions of swimming forward,turning and positioning were realized.

关键词： underwater robot open-loop control IPMC swing property displacement response

China's Sovereign Wealth Fund:Weakness and Challenges

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China & World Economy 2009年第1期17卷 101-122页

作者： Ming Zhang fan He Assistant Professor Institute of World Economics and Politics Chinese Academy of Social Sciences Beijing China Associate Professor Institute of World Economics and Politics Chinese Academy of Social Sciences Beijing China

The establishment of sovereign wealth funds in large developing countries has generated hot debate among participants in the international financial market. When accumulated foreign exchange reserves surpass a sufficient and an appropriate level, the costs, risks and impacts of holding reserves on the macroeconomy of a country need to be considered. The Chinese Government established China Investment Corporation （ CIC） in 2007 to diversify its investment of foreign reserves and to raise investment income. However, because of certain conflicts of interest and institution-design caveats, CIC possesses some internal weakness, including a vague orientation, mixed investment strategies and an inefficient bureaucratic style. Although the subprime crisis has softened certain regulations and lessened rejection by the USA of ClC potential investments, the increased volatility and uncertainty of the market means that CIC is facing some new challenges in terms of its investment decisions. Moreover, CIC is competing with other Chinese investment institutions for injections of funds from the Chinese Government.

关键词： China Investment Corporation external challenge foreign exchange reserve management internal weakness sovereign wealth fund