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Topological Stability and Entropy for Certain Set-valued Maps

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Acta Mathematica Sinica,English Series 2024年第4期40卷 962-984页

作者： yu ZHANG yu Jun zhu School of Mathematical Sciences Xiamen UniversityXiamen 361005P.R.China

In this paper,the dynamics(including shadowing property,expansiveness,topological stability and entropy)of several types of upper semi-continuous set-valued maps are mainly considered from differentiable dynamical systems points of *** is shown that(1)if f is a hyperbolic endomorphism then for eachε>0 there exists a C^(1)-neighborhood U of f such that the induced set-valued map F_(f,U)has theε-shadowing property,and moreover,if f is an expanding endomorphism then there exists a C^(1)-neighborhood U of f such that the induced set-valued map F_(f,U)has the Lipschitz shadowing property;(2)when a set-valued map F is generated by finite expanding endomorphisms,it has the shadowing property,and moreover,if the collection of the generators has no coincidence point then F is expansive and hence is topologically stable;(3)if f is an expanding endomorphism then for eachε>0 there exists a C^(1)-neighborhood U of f such that h(F_(f,U,ε))=h(f);(4)when F is generated by finite expanding endomorphisms with no coincidence point,the entropy formula of F is ***,the dynamics of the set-valued maps based on discontinuous maps on the interval are also considered.

关键词： Set-valued map orbit space hyperbolic endomorphism perturbation shadowing expansiveness topological stability entropy

Tongmai Yangxin Pill combined with metoprolol or metoprolol alone for the treatment of symptomatic premature ventricular complex:a multicenter,randomized,parallel-controlled clinical study

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Journal of Geriatric Cardiology 2022年第4期19卷 284-291页

作者： Li-Jun LIU Guo-Hua zhu Hong-yu LUO xi-Peng SUN Jing LI Qi HUA Department of Cardiology Xuanwu Hospital Capital Medical UniversityBeijingChina Department of Geriatrics Xuanwu Hospital Capital Medical UniversityBeijingChina

OBJECTIVE To investigate the effects of Tongmai Yangxin Pill(TMYXP)combined with metoprolol tartrate or metoprolol alone for the treatment of premature ventricular complex(PVC)in patients with symptomatic frequent *** A total of 584 patients with symptomatic frequent PVC were randomly assigned(in a 1:1 ratio)into two groups:study group[n=292,TMYXP(40 pills twice/day,orally)combined with metoprolol tartrate(25 mg twice/day,orally)]and control group[n=292,metoprolol tartrate(25 mg twice/day,orally)plus placebo pill(40 pills twice/day,orally)].The total treatment period was eight *** After eight weeks of treatment,the total effective rate of reduction of PVC in the study group and the control group were 76.4%and 51.4%,respectively(P<0.001).TMYXP combined with metoprolol tartrate demonstrated a significantly greater reduction of the frequency of PVCs compared with the metoprolol tartrate alone(−4537 times/24 h vs.−3013 times/24 h,P<0.001).The study group also showed a better result compared with the control group with respect to PVC related *** terms of New York Heart Association classification improvement,the total effective rates were 21.9%in the study group and 12.4%in the control group(P<0.05).Both the study group and the control group exhibited improvements in echocardiographic *** ventricular ejection fraction was significantly improved in the study group compared with the control group(P<0.05).There was no significant difference in the incidence of adverse events between the two *** Compared with metoprolol tartrate alone,TMYXP combined with metoprolol tartrate could more effectively reduce the frequency of PVC and alleviated PVC related symptoms,and improve cardiac function in patients with symptomatic PVC.

关键词： treatment alone complex

Groove formation on Phobos from reimpacting orbital ejecta of the Stickney crater

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Earth and Planetary Physics 2022年第3期6卷 294-303页

作者： xiangyu xi Min Ding MengHua zhu State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacaoChina China National Space Administration Macao Center for Space Exploration and ScienceMacaoChina

Numerous linear grooves have long been recognized as covering the surface of Phobos, but the mechanisms of their formation are still unclear. One possible mechanism is related to the largest crater on Phobos, the Stickney crater, whose impact ejecta may slide,roll, bounce, and engrave groove-like features on Phobos. When the launch velocity is higher than the escape velocity, the impact ejecta can escape Phobos. A portion of these high-velocity ejecta are dragged by the gravitational force of Mars, fall back, and reimpact *** this research, we numerically test the hypothesis that the orbital ejecta of the Stickney crater that reimpact Phobos could be responsible for a particular subset of the observed grooves on Phobos. We adopt impact hydrocode i SALE-2 D(impact-Simplified Arbitrary Lagrangian Eulerian, two-dimensional) to simulate the formation of the Stickney crater and track its impact ejecta, with a focus on orbital ejecta with launch velocities greater than the escape velocity of Phobos. The launch velocity distribution of the ejecta particles is then used to calculate their trajectories in space and determine their fates. For orbital ejecta reimpacting Phobos, we then apply the sliding boulder model to calculate the ejecta paths, which are compared with the observed groove distribution and length to search for causal relationships. Our ejecta trajectory calculations suggest that only ~1% of the orbital ejecta from the Stickney crater can reimpact Phobos. Applying the sliding boulder model, we predict ejecta sliding paths of 9-20 km in a westward direction to the east of the zone of avoidance, closely matching the observed grooves in that region. The best-fit model assumes an ejecta radius of ~150 m and a speed restitution coefficient of 0.3, consistent with the expected ejecta and regolith properties. Our calculations thus suggest the groove class located to the east of the zone of avoidance may have been caused by reimpact orbital ejecta from the Stick

关键词： Phobos groove formation Stickney crater reimpact ejecta

Solving local constraint condition problem in slave particle theory with the BRST quantization

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Communications in Theoretical Physics 2023年第9期75卷 173-181页

作者： xi Luo Jianqiao Liu yue yu College of Science University of Shanghai for Science and TechnologyShanghai 200093China Department of Physics Fudan UniversityShanghai 200433China

With the Becchi-Rouet-Stora-Tyutin(BRST) quantization of gauge theory,we solve the long-standing difficult problem of the local constraint conditions,*** single occupation of a slave particle per site,in the slave particle *** difficulty is actually caused by inconsistently dealing with the local Lagrange multiplier λ_(i) which ensures the constraint:in the Hamiltonian formalism of the theory,λ_(i) is time-independent and commutes with the Hamiltonian while in the Lagrangian formalism,λ_(i)(t) becomes time-dependent and plays a role of gauge *** implies that the redundant degrees of freedom of λ_(i)(t) are introduced and must be removed by the additional constraint,the gauge fixing condition(GFC) ?_tλ_(i)(t)= *** literature,this GFC was *** add this GFC and use the BRST quantization of gauge theory for Dirac's first-class constraints in the slave particle *** GFC endows λ_(i)(t) with dynamics and leads to important physical *** an example,we study the Hubbard model at half-filling and find that the spinon is gapped in the weak U and the system is indeed a conventional metal,which resolves the paradox that the weak coupling state is a superconductor in the previous slave boson mean field(MF) *** the t-J model,we find that the dynamic effect of λ_(i)(t) substantially suppresses the d-wave pairing gap and then the superconducting critical temperature may be lowered at least a factor of one-fifth of the MF value which is of the order of 1000 *** renormalized T_c is then close to that in cuprates.

关键词： slave particle BRST gauge theory high T_c superconductivity Hubbard model t–J model

Boosting ultra-wide temperature dielectric stability of multilayer ceramic capacitor through tailoring the combination types of polar nanoregions

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Journal of Materiomics 2024年第4期10卷 751-761页

作者： Jiacheng Liu Kaibiao xi Beibei Song Huarong Cheng xiaole yu Mupeng Zheng Mankang zhu yudong Hou College of Materias Science and Engineering Key Laborutory of Advanced Functional Materials Education Ministry of China Beijing University of TechnologyBeijing100124China Materials R&D Department Beijing Yuanliu Hongyuan Eletronic Technology CompanyLtdBeijing102600China

With the rapid development of space exploration and new energy vehicles,it is urgent to build ultra-wide temperature multilayer ceramic capacitors(UWT MLCCs)to match electronic circuits that can withstand harsh environmental *** ferroelectrics with diffuse phase transition feature are potential dielectrics for the construction of UWT ***,how to ensure high dielectric constant together with low dielectric loss in the wide temperature region is still a big ***,the above difficulties are addressed by tailoring the combination types of polar nanoregions(PNRs)in the(1-x)(0.8Na_(0.5)Bi_(0.5)TiO_(3)-0.2K_(0.5)Bi_(0.5)TiO_(3))-xNaTaO3(NBT-KBT-xNT)*** with PNRS types of P4bm+R3c and P4bm+Pbnm,the combination type of P4bm+Pbnm+R3c PNRs in NBT-KBT-0.31NT is the most beneficial to obtain comprehensive excellent dielectric performance because it can balance the relationship between high dielectric constant and temperature stability over a wide temperature ***,by optimizing the laminating pressure and co-firing temperature to realize a tight interfacial structure between the dielectric layer and the Pt inner electrode,a record-high dielectric constant(er=(907%±15%))together with low dielectric loss(tan δ≤0.025)is achieved over an ultra-wide range from-61℃ to 306℃ for NBT-KBT-0.31 NT MLCC,demonstrating that tailoring the combination types of PNRs is a powerful strategy in designing UWT MLCC dielectrics.

关键词： Lead-free dielectrics Ultra-wide temperature Multilayer ceramic capacitor Polar nanoregion

Seasonal change of circulating leptin associated with testicular activities of the wild ground squirrels(Citellus dauricus)

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Integrative Zoology 2023年第1期18卷 76-92页

作者： Wenyang yu Sijie FAN xi WANG Jueyu zhu Zhengrong yuAN Yingying HAN Haolin ZHANG Qiang WENG Laboratory of Animal Physiology College of Biological Sciences and TechnologyBeijing Forestry UniversityBeijingChina

The purpose of this study was to explore the variations in the circulating leptin concentrations of the wild ground squirrels in relation to seasonal changes in testicular ***-eosin staining showed all types of elongated spermatids and spermatogenic cells existed in the testis in April,while the primary spermatocytes and spermatogonia were most advanced stages of germ cells in *** addition,the primary spermatocytes,secondary spermatocytes,and spermatogonia were most advanced stages of germ cells in *** highest circulating leptin concentration was consistent with the maximum body weight results from accumulation of adipose tissue in *** mRNA expression level of leptin receptor(Ob-R)and STAT3 was lowest in June,raised in September,and remained increased in ***-R and STAT3 were stronger staining in the Leydig cells in ***,the concentrations of testosterone(T)showed the maximum values in April,the minimum values in June,and signiﬁcant increases in ***,it is worth noting that the levels of T increased with the mRNA levels of Ob-R,STAT3,StAR,and testicular steroidogenic enzymes(3β-HSD,P450c17,and P450scc).Moreover,RNA-seq analyses of testis during the different periods showed that a total of 4209 genes were differ-entially expressed genes(DEGs);further analysis revealed that DEGs related with the Jak/STAT pathways and reproduction were *** together,the results suggested that the leptin regulated testicular function through the Jak/STAT pathways and testicular steroidogenic factor expressions.

关键词： leptin Ob-R STAT3 steroidogenic enzyme testis wild ground squirrel

Impact of the microbiome on mosquito-borne diseases

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Protein & Cell 2023年第10期14卷 743-761页

作者： Huicheng Shi xi yu Gong Cheng Tsinghua University-Peking University Joint Center for Life Sciences School of MedicineTsinghua UniversityBeijing 100084China Institute of Infectious Diseases Shenzhen Bay LaboratoryShenzhen 518000China Department of Parasitology School of Basic Medical SciencesCentral South UniversityChangsha 410013China

Mosquito-borne diseases present a significant threat to human health,with the possibility of outbreaks of new mosquito-borne diseases always ***,current measures to combat these diseases such as vaccines and drugs are often either unavailable or ***,recent studies on microbiomes may reveal promising strategies to fight these *** this review,we examine recent advances in our understanding of the effects of both the mosquito and vertebrate microbiomes on mosquito-borne *** argue that the mosquito microbiome can have direct and indirect impacts on the transmission of these diseases,with mosquito symbiotic microorganisms,particularly Wolbachia bacteria,showing potential for controlling mosquito-borne ***,the skin microbiome of vertebrates plays a significant role in mosquito preferences,while the gut microbiome has an impact on the progression of mosquito-borne diseases in *** researchers continue to explore the role of microbiomes in mosquito-borne diseases,we highlight some promising future directions for this ***,a better understanding of the interplay between mosquitoes,their hosts,pathogens,and the microbiomes of mosquitoes and hosts may hold the key to preventing and controlling mosquito-borne diseases.

关键词： microbiome mosquito mosquito-borne viruses malaria pathogen transmission

Asymmetric Loss Based on Image Properties for Deep Learning-Based Image Restoration

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Computers, Materials & Continua 2023年第12期77卷 3367-3386页

作者： Linlin zhu yu Han xiaoqi xi Zhicun Zhang Mengnan Liu Lei Li Siyu Tan Bin Yan Henan Key Laboratory of Imaging and Intelligent Processing PLA Strategic Support Force Information Engineering UniversityZhengzhou450000China

Deep learning techniques have significantly improved image restoration tasks in recent *** a crucial compo-nent of deep learning,the loss function plays a key role in network optimization and performance ***,the currently prevalent loss functions assign equal weight to each pixel point during loss calculation,which hampers the ability to reflect the roles of different pixel points and fails to exploit the image’s characteristics *** address this issue,this study proposes an asymmetric loss function based on the image and data characteristics of the image recovery *** novel loss function can adjust the weight of the reconstruction loss based on the grey value of different pixel points,thereby effectively optimizing the network training by differentially utilizing the grey information from the original ***,we calculate a weight factor for each pixel point based on its grey value and combine it with the reconstruction loss to create a new loss *** ensures that pixel points with smaller grey values receive greater attention,improving network *** order to verify the effectiveness of the proposed asymmetric loss function,we conducted experimental tests in the image super-resolution *** experimental results show that the model with the introduction of asymmetric loss weights improves all the indexes of the processing results without increasing the training *** the typical super-resolution network SRCNN,by introducing asymmetric weights,it is possible to improve the peak signal-to-noise ratio(PSNR)by up to about 0.5%,the structural similarity index(SSIM)by up to about 0.3%,and reduce the root-mean-square error(RMSE)by up to about 1.7%with essentially no increase in training *** addition,we also further tested the performance of the proposed method in the denoising task to verify the potential applicability of the method in the image restoration task.

关键词： Deep learning image restoration loss function image properties super resolution image denoising

Impact of the COVID-19 pandemic on agricultural exports

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Journal of Integrative Agriculture 2020年第12期19卷 2937-2945页

作者： LIN Ben-xi yu Yvette ZHANG School of Economics Fujian Agriculture and Forestry UniversityFuzhou 350002P.R.China Department of Agricultural Economics Texas A&M UniversityCollege StationTX 77843USA

The COVID-19 outbreak has shocked the world’s economies in the year of *** this pandemic spreads around the globe,many experts feared that the global food supplies might start running short,especially if supply chains were ***-19 also added to the uncertainty of the business ***,it is critical to understand how COVID-19 pandemic affected global food supply and *** this study,we investigate the impact of COVID-19 on agricultural export companies in China using a unique firm-level survey *** found that although on average agricultural businesses experienced declines in the exports,exports of some agricultural products especially grain and oil held strong and even increased,implying the essential demand for staple food during the *** surprisingly,exports of medicinal herb also increased significantly during the ***,exports of goods such as edible fungus and horticultural products sharply *** results also showed that in general,impact of COVID-19 on smaller firms was more severe than that on larger *** results of this study can provide useful guidance and implications for agricultural businesses and policy makers on their COVID-19 mitigation efforts to navigate this global pandemic.

关键词： COVID-19 pandemic agricultural exports business survey international trade China