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Global Optimization of a Class of Nonconvex Quadratically Constrained Quadratic Programming Problems

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Acta Mathematica Sinica,English Series 2011年第9期27卷 1803-1812页

作者： Yong Xia LMIB of the Ministry of Education School of Mathematics and Systems Science Beihang University Beijing 100191 P. R. China

In this paper we study a Class of nonconvex quadratically constrained quadratic programming problems generalized from relaxations of quadratic assignment problems. We show that each problem is polynomially solved. Strong duality holds if a redundant constraint is introduced. As an application, a new lower bound is proposed for the quadratic assignment problem.

关键词： Nonconvex programming quadratically constrained quadratic programming quadratic assignment problem polynomial solvability strong duality

Numerical simulations for radon migration and exhalation behavior during measuring radon exhalation rate with closed-loop method

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Nuclear Science and Techniques 2024年第1期35卷 81-95页

作者： Ming xia yong-Jun Ye Shu-Yuan Liu School of Resources Environment and Safety Engineering University of South ChinaHengyang 421001China Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy University of South ChinaHengyang 421001China

Accurate measurements of the radon exhalation rate help identify and evaluate radon risk regions in the environment.Among these measurement methods,the closed-loop method is frequently used.However,traditional experiments are insufficient or cannot analyze the radon migration and exhalation patterns at the gas–solid interface in the accumulation chamber.The CFD-based technique was applied to predict the radon concentration distribution in a limited space,allowing radon accumulation and exhalation inside the chamber intuitively and visually.In this study,three radon exhalation rates were defined,and two structural ventilation tubes were designed for the chamber.The consistency of the simulated results with the variation in the radon exhalation rate in a previous experiment or analytical solution was verified.The effects of the vent tube structure and flow rate on the radon uniformity in the chamber;permeability,insertion depth,and flow rate on the radon exhalation rate and the effective diffusion coefficient on back-diffusion were investigated.Based on the results,increasing the inser-tion depth from 1 to 5 cm decreased the effective decay constant by 19.55%,whereas the curve-fitted radon exhalation rate decreased(lower than the initial value)as the deviation from the initial value increased by approximately 7%.Increasing the effective diffusion coefficient from 2.77×10^(-7) to 7.77×10^(-6) m^(2) s^(-1) made the deviation expand from 2.14 to 15.96%.The conclusion is that an increased insertion depth helps reduce leakage in the chamber,subject to notable back-diffusion,and that the closed-loop method is reasonably used for porous media with a low effective diffusion coefficient in view of the back-diffusion effect.The CFD-based simulation is expected to provide guidance for the optimization of the radon exhalation rate measurement method and,thus,the accurate measurement of the radon exhalation rate.

关键词： Radon exhalation Numerical simulation Accumulation chamber

Finite-time fault-tolerant control of teleoperating cyber physical system against faults

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Journal of Systems Engineering and Electronics 2023年第2期34卷 469-478页

作者： PAN Chengwei LIU xia CHEN yong LI Meng School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu 611731China Institute of Electric Vehicle Driving System and Safety Technology University of Electronic Science and Technology of ChinaChengdu 611731China School of Electrical Engineering and Electronic Information Xihua UniversityChengdu 610039China

This paper studies a finite-time adaptive fractionalorder fault-tolerant control(FTC)scheme for the slave position tracking of the teleoperating cyber physical system(TCPS)with external disturbances and actuator faults.Based on the fractional Lyapunov stability theory and the finite-time stability theory,a fractional-order nonsingular fast terminal sliding mode(FONFTSM)control law is proposed to promote the tracking and fault tolerance performance of the considered system.Meanwhile,the adaptive fractional-order update laws are designed to cope with the unknown upper bounds of the unknown actuator faults and external disturbances.Furthermore,the finite-time stability of the closed-loop system is proved.Finally,comparison simulation results are also provided to show the validity and the advantages of the proposed techniques.

关键词： teleoperating cyber physical system(TCPS) fractional Lyapunov stability fault-tolerant control(FTC) finite-time stability

An Experimental Study of Partial Melting of Metafelsic Rocks:Constraints on the Feature of Anatectic Melts and the Origin of Garnets in Collisional Orogens

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Journal of Earth Science 2022年第3期33卷 753-769页

作者： Xu Luo Qiong-xia xia yong-Fei Zheng Wan-Cai Li CAS Key Laboratory of Crust-Mantle Materials and Environments School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Center of Excellence in Comparative Planetology Chinese Academy of Sciences(CAS)Hefei 230026China Department of Earth Environmental and Planetary SciencesCase Western Reserve UniversityCleveland OH 44106USA

Crustal anatexis in continental subduction zones has great bearing on chemical differentiation of the continental crust at convergent plate boundaries.This was experimentally investigated for ultrahigh-pressure(UHP)metafelsic rocks at 0.5-3.0 GPa and 650-900℃.The results show that partial melting begins at about 750℃ when pressure drops from 3.0 to 2.0 GPa,corresponding to decompressional exhumation of the deeply subducted continental crust.As the pressure further decreases to 1.0 GPa,the partial melting degree reaches the maximum of~25%at 900℃.Partial melts produced in these experiments are rich in silica and alkali,and poor in iron,manganese and magnesium.As the degree of partial melting increases,the composition of partial melts gradually converges toward homogeneous one.In the absence of free water,the partial melting of metafelsic rocks were triggered by the breakdown of hydrous minerals.At low temperatures of~750℃at 1.0-2.0 GPa,phengite dehydration melting occurs at first,giving rise to small amounts of felsic melts and peritectic K-feldspar.As the temperature rises up to 850-900℃,biotite begins to break down and gives rise to large amounts of felsic melts and peritectic minerals such as garnet,K-feldspar and orthopyroxene.It is noted that peritectic garnet is much different from anatectic garnet crystallized from anatectic melts and metamorphic garnet formed through metamorphic dehydration reaction under subsolidus conditions.The peritectic garnet is characterized not only by anhedral shapes with many multiphase crystal inclusions but also by compositions poor in spessartine and grossular but rich in almandine and pyrope.On the other hand,the anatectic garnets are characterized not only by euhedral shapes with few inclusions but also by compositions rich in grossular and spessartine but poor in almandine and pyrope.These observations provide experimental constraints on the origin of garnets in UHP metamorphic rocks,which have great bearing on understanding of anatectic metamorphism in collisional orogens.

关键词： collisional orogen partial melting experimental petrology metafelsic rocks garnet melts

Three-Dimensional Wave-Induced Current Model Equations and Radiation Stresses

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China Ocean Engineering 2017年第4期31卷 418-427页

作者： xia Hua-yong South China Sea Marine Forecast Center State Oceanic administrationGuangzhou 510300China

After the approach by Mellor （2003, 2008）, the present paper reports on a repeated effort to derive the equations for three-dimensional wave-induced current. Via the vertical momentum equation and a proper coordinate transformation, the phase-averaged wave dynamic pressure is well treated, and a continuous and depth-dependent radiation stress tensor, rather than the controversial delta Dirac function at the surface shown in Mellor （2008）, is provided. Besides, a phase-averaged vertical momentum flux over a sloping bottom is introduced. All the inconsistencies in Mellor （2003, 2008）, pointed out by Ardhuin et al. （2008） and Bennis and Ardhuin （2011）, are overcome in the presently revised equations. In a test case with a sloping sea bed, as shown in Ardhuin et al. （2008）, the wave-driving forces derived in the present equations are in good balance, and no spurious vertical circulation occurs outside the surf zone, indicating that Airy’s wave theory and the approach of Mellor （2003, 2008） are applicable for the derivation of the wave-induced current model.

关键词： sea surface wave wave-induced current radiation stress vertical wave momentum flux

城市低保制度的功能定位和实践机制及演化逻辑

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西北大学学报（哲学社会科学版） 2018年第6期48卷 61-70页

作者：张永春黄晓夏西安市社会科学院陕西西安710054 西北大学公共管理学院陕西西安710069

将我国城市低保制度定位成一种托底性社会救助政策,通过分析其实践中的供给要素及运行机制,提出低保制度向着目标理念转型、责任主体互融和职能结构优化的演化逻辑,由此进行绩效优化。我国城市低保以福利资源为基石,在政府政策的推动下... 详细信息

将我国城市低保制度定位成一种托底性社会救助政策,通过分析其实践中的供给要素及运行机制,提出低保制度向着目标理念转型、责任主体互融和职能结构优化的演化逻辑,由此进行绩效优化。我国城市低保以福利资源为基石,在政府政策的推动下,通过一定的实施程序使目标人群受益,就是这一实践机理运作的过程。笔者建议以申保对象的需求为参照物,建立一套涵盖低保对象的收入、健康状况、劳动能力及家庭结构属性在内的四维指标,以此对申保对象进行精准识别,确定最需要救助的贫困人员。

关键词：城市低保社会救助恩格尔系数法

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当代医学科学(英文) 2023年第3期43卷 579-584页

作者： Yi xia Han-yong ZHANG Sha MA Fang ZHOU The Second Clinical Medical College Tongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China School of Stomatology Tongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China Department of Reproductive Center Wuhan Children's Hospital(Wuhan Maternal and Child Healthcare Hospital)Tongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430015China Department of Reproductive Medicine Maternal and Child Health Hospital of Hubei ProvinceTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430070China

Objective This study examined humanin expression in rat ovarian tissue,its cellular localization,and its correlation with rat age under physiological conditions.Methods A total of 40 Sprague-Dawley rats of various ages(2,12,30,and 60 days old and 1 year old)were grouped by age.Immunofluorescence and immunohistochemical techniques were used to observe humanin expression and cellular location in the ovarian tissues of rats from each age group.In addition,Western blotting and Real-time quantitative reverse transcription PCR(qRT-PCR)techniques were used to measure humanin expression level in the ovarian tissues of rats from each age group.Results The immunofluorescence and immunohistochemical results confirmed that humanin was expressed in rat ovarian tissues.In addition,cellular localization analysis showed that humanin was expressed in the cytoplasm of oocytes,interstitial cells,granulosa cells and theca cells in all levels of follicles after the primary follicles,and in the corpus luteum.The qRT-PCR results revealed that the level of humanin expression in the ovarian tissues of 12-day-old rats was non-significantly higher than that in the ovarian tissues of 2-day-old rats(P>0.05),whereas the levels of humanin expression in the ovarian tissues of 30-day-old,60-day-old,and 1-year-old rats were significantly lower than that in the ovarian tissues of 2-day-old rats(P<0.05).The Western blotting results demonstrated that the levels of humanin protein expression in the ovarian tissues of 60-day-old and 1-year-old rats were significantly lower than those of 2-day-old rats(P<0.01),whereas there was no significant difference in the level of humanin protein expression between the ovarian tissues of 12-day-old and 30-day-old rats.Conclusion This study confirmed that humanin is expressed in the cytoplasm of various cells in rat ovarian tissues.Moreover,the level of humanin expression was highest in the ovarian tissues of 12-day-old rats,and it subsequently decreased with age.The changes in the expression of humanin in the ovar

关键词： humanin ovarian aging rat female fertility

A Study of 10 Rotating Radio Transients Using Parkes Radio Telescope

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Research in Astronomy and Astrophysics 2024年第4期24卷 114-123页

作者： Xinhui Ren Jingbo Wang Wenming Yan Jintao Xie Shuangqiang Wang Yirong Wen Yong Xia Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China Institute of Optoelectronic Technology Lishui UniversityLishui 323000China Xinjiang Key Laboratory of Radio Astrophysics Urumqi 830011China Research Center for Intelligent Computing Platforms Zhejiang LaboratoryHangzhou 311100China

Rotating Radio Transients(RRATs)are a relatively new subclass of pulsars that emit detectable radio bursts sporadically.We analyzed 10 RRATs observed using the Parkes telescope,with eight of these observed via the ultra-wide-bandwidth low-frequency(UWL)receiver.We measured the burst rate and produced integrated profiles spanning multiple frequency bands for three RRATs.We also conducted a spectral analysis on both integrated pulses and individual pulses of three RRATs.All of their integrated pulses follow a simple power law,consistent with the known range of pulsar spectral indices.Their average spectral indices of single pulses are-0.9,-1.2,and-1.0 respectively,which are within the known range of pulsar spectral indices.Additionally,we find that the spreads of single-pulse spectral indices for these RRATs(ranging from-3.5 to+0.5)are narrower compared to what has been observed in other RRATs.Notably,the average spectral index and scatter of single pulses are both relatively small.For the remaining five RRATs observed at the UWL receiver,we also provide the upper limits on fluence and flux density.In addition,we obtain the timing solution of PSR J1709-43.Our analysis shows that PSRs J1919+1745,J1709-43,and J1649-4653 are potentially nulling pulsars or weak pulsars with sparse strong pulses.

关键词： (stars:)pulsars:general stars:neutron stars:individual(PSRs J1919+1745.1909+0641,0628+0909)

Equilibrium dividend strategies in the dual model with a random time horizon

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Applied Mathematics(A Journal of Chinese Universities) 2023年第4期38卷 510-522页

作者： ZHAO yong-xia YE Chuan-xiu CHENG Gong-pin School of Statistics and Data Science Qufu Normal UniversityQufu 273165China School of Mathematical Sciences Qufu Normal UniversityQufu 273165China School of Economics Nanjing University of Finance and EconomicsNanjing 210046China

This paper investigates the dividend problem with non-exponential discounting in a dual model.We assume that the dividends can only be paid at a bounded rate and that the surplus process is killed by an exponential random variable.Since the non-exponential discount function leads to a time inconsistent control problem,we study the equilibrium HJB-equation and give the associated verification theorem.For the case of a mixture of exponential discount functions and exponential gains,we obtain the explicit equilibrium dividend strategy and the corresponding equilibrium value function.Besides,numerical examples are shown to illustrate our results.

关键词： equilibrium dividend strategies non-exponential discounting time inconsistence dual model equilibrium HJB-equation