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国际医学放射学杂志 2021年第4期44卷 493-494页

作者： Z.liu X.li B.Feng C.li Y.Chen l.yi 边甜甜

摘要目的探讨简化乳腺 MRI 最大强度投影 (MIP)影像排除乳腺癌病人隐匿性乳头乳晕复合体(NAC)受累的价值。方法本前瞻性研究纳入了 2016 年 4 月—2019 年 5 月

关键词：保留乳头乳腺癌乳腺切除术 MIP MRI

汶川M_S8.0地震后中国四川西部温泉气的地球化学特征

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世界地震译丛 2019年第6期50卷 556-572页

作者： X.C.Zhou W.C.Wang Z.Chen l.yi l.liu C.Xie Y.J.Cui J.G.Du J.W.Cheng l.M.Yang 赵霞(译) 潘红芹(译) 吴珍云(校) 不详江苏省地震局东华理工大学地球科学学院

为了探讨汶川MS8.0地震与温泉气地球化学特征之间的关系,分别在2008年6月、10月和2009年6月对中国西南地区四川西部32处温泉气进行了调查和样品采集,并针对三批次气样中的化学成分和He,Ne,C同位素比值进行了分析。数据显示,龙门山断裂... 详细信息

为了探讨汶川MS8.0地震与温泉气地球化学特征之间的关系,分别在2008年6月、10月和2009年6月对中国西南地区四川西部32处温泉气进行了调查和样品采集,并针对三批次气样中的化学成分和He,Ne,C同位素比值进行了分析。数据显示,龙门山断裂带、鲜水河断裂带和岷江断裂带的温泉气中3He/4He,δ13CCO2含量在汶川大地震发生后明显增加。根据2008年6月测得的3He/4He最大值(7.42×10-6),预估在康定地区有高达62%的地幔氦增加进入到了温泉气中。随着时间的推移,地幔流体对温泉的贡献逐渐减少,但壳源气体,如有机物衍生出的CO2和CH4以及放射生成的He,其成分有所增强。温泉气的地球化学数据表明,在汶川MS8.0地震后,四川西部地区有更多的地幔流体迁移进入地壳中。

关键词：气体地球化学地震温泉同位素比值汶川

Multi-objective quality control method for cold-rolled products oriented to customized requirements

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International Journal of Minerals,Metallurgy and Materials 2021年第8期28卷 1332-1342页

作者： yi-fan Yan Zhi-min lü Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China

To deal with the increasing demand for low-volume customization of the mechanical properties of cold-rolled products, a two-way control method based on mechanical property prediction and process parameter optimization(PPO) has become an effective solution. Aiming at the multi-objective quality control problem of a company's cold-rolled products, based on industrial production data, we proposed a process parameter design and optimization method that combined multi-objective quality prediction and PPO. This method used the multi-output support vector regression(MSVR) method to simultaneously predict multiple quality indices. The MSVR prediction model was used as the effect verification model of the PPO results. It performed multi-process parameter collaborative design and realized the optimization of production process parameters for customized multi-objective quality requirements. The experimental results showed that, compared with the traditional single-objective quality prediction model based on support vector regression(SVR), the multi-objective prediction model could better take into account the coupling effect between process parameters and quality index, the MSVR model prediction accuracy was higher than that of the SVR, and the optimized process parameters were more capable and reflected the influence of metallurgical mechanism on the quality index,which were more in line with actual production process requirements.

关键词： customized production quality control multi-objective prediction multi-output support vector regression process parameter optimization

Experimental study on fusion and break-up motion after droplet collision

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Chinese Journal of Chemical Engineering 2020年第3期28卷 712-720页

作者： yi li Zhi Ning Ming lü Beijing Jiaotong University School of MechanicalElectronic and Control EngineeringBeijing 100044China Beijing Jiaotong University Beijing Key Lab Powertrain New Energy VehicleBeijing 100044China

The interactions between droplets have an important influence on the atomization of liquid fuel,the combustion efficiency,and the reduction of particulate matter emissions for an *** this reason,this paper presents results from an experimental study on the coalescence and break-up of droplets after *** to the shape and parameters of the droplets at different times after the collision of the droplets was captured by a high speed camera,analysis was done for the following effects of droplet collisions:the collision-coalescence motion for the collision between the droplets,the change history of the dimensionless length-to-width ratio of the oscillation motion,the critical size ratio of the breakup motion,and the liquid physical properties of the *** results show that the droplets collide and exhibit two forms of coalescence oscillation and break-up:for oscillating motion,at higher droplet collision velocities and dimensionless size ratios,there will be a larger dimensionless length-to-width ratio for the droplet oscillation;for the break-up motion,at higher collision velocities,there will be lower dimensionless size ratios,and lower liquid surface tension,shorter times over which the droplet breaks,and facilitated droplet *** research results presented here can be used for atomization in engine cylinder,increasing the gas/liquid contact area and enhancing the combustion efficiency of gas/liquid heat transfer to improve the combustion efficiency of the engine.

关键词： Collision between droplets Size ratio Collision velocity Broken moment

Analysis and Inverse Substructuring Computation on Dynamic Quality of Mechanical Assembly

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Chinese Journal of Mechanical Engineering 2016年第3期29卷 539-548页

作者： lü Guangqing yi Chuijie FANG Ke Key lab of Disasters Forecast and Control in Engineering of Ministry of Education Jinan University Research Center of Equipment Energy & Environment Qingdao Technological University

Mechanical assembly has its own dynamic quality directly affecting the dynamic quality of whole product and should be considered in quality inspection and estimation of mechanical assembly. Based on functional relations between dynamic characteristics involved in mechanical assembly, the effects of assembling process on dynamic characteristics of substructural components of an assembly system are investigated by substructuring analysis. Assembly-coupling dynamic stiffness is clarified as the dominant factor of the effects and can be used as a quantitative measure of assembly dynamic quality. Two computational schemes using frequency response functions（FRFs） to determine the stiffness are provided and discussed by inverse substructuring analysis, including their applicable conditions and implementation procedure in application. Eigenvalue analysis on matrix-ratios of FRFs before and after assembling is employed and well validates the analytical outcomes and the schemes via both a lumped-parameter model and its analogic experimental counterpart. Applying the two schemes to inspect the dynamic quality provides the message of dynamic performance of the assembly system, and therefore improves conventional quality inspection and estimation of mechanical assembly in completeness.

关键词： mechanical assembly dynamic quality substructuring analysis inverse substructuring assembly-coupling dynamic stiffness

Quantum Mechanics Version of Wavelet Transform Studied by Virtue of IWOPTechnique

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Communications in Theoretical Physics 2004年第5期41卷 681-684页

作者： FANHong-yi lǖJian-Feng DepartmentofPhysics ShanghaiJiaoTongUniversityShanghai200030China

Using the technique of integral within an ordered product (IWOP) of operators we show that the wavelet transform can be recasted to a matrix element of squeezing-displacing operator between the mother wavelet state vector and the state vector to be transformed in the context of quantum mechanics. In this way many quantum optical states'wavelet transform can be easily derived.

关键词： wavelet transform IWOP technique squeezing-displacing operator

Parameter identification and synchronization of spatiotemporal chaos in an uncertain Gray-Scott system

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Science China(Physics,Mechanics & Astronomy) 2008年第11期51卷 1638-1646页

作者： lüling lI yi GUO ZhiAn College of Physics and Electronic Technology Liaoning Normal UniversityDalian 116029China Department of Mathematics and Physics Dalian Jiaotong UniversityDalian 116028China

The zero-asymptotic property of sliding variables in discrete systems is extended to a continuous one and applied to partial differential equations which describe spatiotemporal chaos. A method of chaos synchronization and parameter identifi-cation is proposed. The synchronization controllers and the parameter recognizers are designed. The uncertain Gray-Scott system is taken as an example to verify the effectiveness of the method. Simulation results show that the identification vari-ables in the parameter recognizers may take the place of the unknown parameters in both target and response systems. Global synchronization of the two spatio-temporal chaotic systems with uncertain parameters may be realized quickly after controllers are added.

关键词： spatiotemporal chaos sliding variable parameter identification synchronization uncertain Gray-Scott system

Different effects of economic and structural performance indexes on model construction of structural topology optimization

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Acta Mechanica Sinica 2015年第5期31卷 777-788页

作者： G.l.yi Y.K.Sui College of Mechanical Engineering and Applied Electronics Technology Beijing University of Technology Department of Mechanical and Aerospace Engineering Seoul National University

The objective and constraint functions related to structural optimization designs are classified into economic and performance indexes in this *** influences of their different roles in model construction of structural topology optimization are also ***,two structural topology optimization models,optimizing a performance index under the limitation of an economic index,represented by the minimum compliance with a volume constraint（MCVC）model,and optimizing an economic index under the limitation of a performance index,represented by the minimum weight with a displacement constraint（MWDC）model,are *** on a comparison of numerical example results,the conclusions can be summarized as follows：（1）under the same external loading and displacement performance conditions,the results of the MWDC model are almost equal to those of the MCVC model;（2）the MWDC model overcomes the difficulties and shortcomings of the MCVC model;this makes the MWDC model more feasible in model construction;（3）constructing a model of minimizing an economic index under the limitations of performance indexes is better at meeting the needs of practical engineering problems and completely satisfies safety and economic requirements in mechanical engineering,which have remained unchanged since the early days of mechanical engineering.

关键词： Economic index Performance index Structural topology optimization models MCVC model MWDC model Safety and economy

Machine learning methods for predicting CO_(2) solubility in hydrocarbons

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Petroleum Science 2024年第5期21卷 3340-3349页

作者： yi Yang Binshan Ju Guangzhong lü yingsong Huang School of Energy Resources China University of Geosciences(Beijing)Beijing100083China Key laboratory of Marine Reservoir Evolution and Hydrocarbon Enrichment Mechanism Ministry of EducationBeijing100083China Key laboratory of Geological Evaluation and Development Engineering of Unconventional Natural Gas Energy Beijing100083China Shengli Oilfield Company SINOPECDongying257015ShandongChina

The application of carbon dioxide(CO_(2)) in enhanced oil recovery(EOR) has increased significantly, in which CO_(2) solubility in oil is a key parameter in predicting CO_(2) flooding performance. Hydrocarbons are the major constituents of oil, thus the focus of this work lies in investigating the solubility of CO_(2) in hydrocarbons. However, current experimental measurements are time-consuming, and equations of state can be computationally complex. To address these challenges, we developed an artificial intelligence-based model to predict the solubility of CO_(2) in hydrocarbons under varying conditions of temperature, pressure, molecular weight, and density. Using experimental data from previous studies,we trained and predicted the solubility using four machine learning models: support vector regression(SVR), extreme gradient boosting(XGBoost), random forest(RF), and multilayer perceptron(MlP).Among four models, the XGBoost model has the best predictive performance, with an R^(2) of ***, sensitivity analysis and evaluation of the relative impacts of each input parameter indicate that the prediction of CO_(2) solubility in hydrocarbons is most sensitive to pressure. Furthermore, our trained model was compared with existing models, demonstrating higher accuracy and applicability of our model. The developed machine learning-based model provides a more efficient and accurate approach for predicting CO_(2) solubility in hydrocarbons, which may contribute to the advancement of CO_(2)-related applications in the petroleum industry.

关键词： CO_(2)solubility Machine learning Support vector regression Extreme gradient boosting Random forest Multi-layer perceptron

Improved Reall-Santos method for AdS black holes in general 4-derivative gravities

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Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 74-86页

作者： Peng-Ju Hu liang Ma Hong lü yi Pang Center for Joint Quantum Studies and Department of Physics School of ScienceTianjin UniversityTianjin 300350China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityFuzhou 350207China Peng Huanwu Center for Fundamental Theory Hefei 230026China

For asymptotically flat black holes,Reall-Santos method is a convenient tool to compute leading higher derivative corrections to the thermodynamic quantities without actually solving the modified field ***,there are subtleties in its generalization to asymptotically AdS black holes with general higher derivative *** of all,it is necessary to know all the higher derivative holographic counterterms and the surface terms implementing the variational principle and subtracting the *** then needs to solve for the modified AdS radius and rescale the time coordinate in an appropriate way such that the induced metric on the conformal boundary of AdS black hole is not *** observe that Reall-Santos method can be directly applied to a particular 4-derivative gravity model,known as the Einstein-Weyl gravity,which does not modify the AdS radius and requires only the Gibbons-Hawking-York term and holographic counterterms for the 2-derivative *** thus suggest that to compute the thermodynamic quantities of AdS black holes in general 4-derivative theories of gravity,one simply needs to transform it to a Einstein-Weyl gravity with identical thermodynamic variables by appropriate field *** explicitly verify this proposal with spherically-symmetric and static charged black holes in Einstein-Maxwell theory extended with generic 4-derivative interactions.

关键词： black holes thermodynamics higher-derivative corrections effective theories higher dimensional black holes quantum gravity