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HARMONIC FUNCTIONS ON A COMPLETE NONCOMPACT MANIFOLD WITH ASYMPTOTICALLY NONNEGATIVE CURVATURE

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Chinese Annals of Mathematics,Series B 2004年第4期25卷 523-532页

作者： zhouchaohui chenzhihua DepartmentofAppliedMathematics TongjiUniversityShanghai200092China.

The authors prove the space of harmonic functions with polynomial growth of a fixed rate on a complete noncompact Riemannian manifold with asymptotically nonnegative curvature is finite dimensional.

关键词： Harmonic function Asymptotically nonnegative curvature Polynomial growth

L-harmonic functions with polynomial growth of a fixed rate

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Science China Mathematics 2009年第12期52卷 2855-2862页

作者： zhou chaohui chen zhihua Department of Mathematics Tongji UniversityShanghai 200092China

Yau made the following conjecture:For a complete noncompact manifold with nonnegative Ricci curvature the space of harmonic functions with polynomial growth of a fixed rate is finite *** extend the result on the Laplace operator to that on the symmetric diffusion operator,and prove the space of L-harmonic functions with polynomial growth of a fixed rate is finitedimensional,when m-dimensional Bakery-Emery Ricci curvature of the symmetric diffusion operator on the complete noncompact Riemannian manifold is nonnegative.

关键词： L-harmonic function symmetric diffusion operator Bakery-Emery Ricci curvature 53C40

L^2-harmonic forms of a complete noncompact Riemannian manifold

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Chinese Science Bulletin 1999年第1期44卷 44-47页

作者： zhihua chen chaohui zhou Tongji Univ Dept Appl Math Shanghai 200092 Peoples R China

Some vanishing theorems are obtained on the L^2-harmonic forms of a complete noncompact Riemannian manifold.

关键词： harmonic form radial sectional curvature Hessian.

A CHARACTERISTIC OF HYPERBOLIC SPACE FORM

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Chinese Annals of Mathematics,Series B 1999年第1期20卷 51-56页

作者： chen zhihua zhou chaohui(Department of Applied Mathematics,Tongji University,Shanghai 200092,China.E-mail:zzzhhc@***) Tongji Univ Dept Appl Math Shanghai 200092 Peoples R China

In this paper, the authors obtain a characteristic that a complete Riemannian manifoldturns into a hyperbolic space form.

关键词： Hyperbolic space form Jacobi field Hessian

High efficient moving object extraction and classification in traffic video surveillance

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Journal of Systems Engineering and Electronics 2009年第4期20卷 858-868页

作者： Li zhihua zhou Fan Tian Xiang chen Yaowu Inst. of Advanced Digital Technology and Instrument Zhejiang Univ. Hangzhou 310027 P. R. China

Moving object extraction and classification are important problems in automated video surveillance systems. A background model based on region segmentation is proposed. An adaptive single Gaussian background model is used in the stable region with gradual changes, and a nonparametric model is used in the variable region with jumping changes. A generalized agglomerative scheme is used to merge the pixels in the variable region and fill in the small interspaces. A two-threshold sequential algorithmic scheme is used to group the background samples of the variable region into distinct Gaussian distributions to accelerate the kernel density computation speed of the nonparametric model. In the feature-based object classification phase, the surveillance scene is first partitioned according to the road boundaries of different traffic directions and then re-segmented according to their scene localities. The method improves the discriminability of the features in each partition. AdaBoost method is applied to evaluate the relative importance of the features in each partition respectively and distinguish whether an object is a vehicle, a single human, a human group, or a bike. Experimental results show that the proposed method achieves higher performance in comparison with the existing method.

关键词： background model nonparametric model adaptive single Gaussian model object classification

Composition design and performance evaluation of rubber-particle cement-stabilized gravel

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Frontiers of Structural and Civil Engineering 2024年第9期18卷 1466-1477页

作者： chaohui WANG Ke YI Feng chen Luqing LIU Xiaolei zhou Zhiwei GAO School of Highway Chang’an UniversityXi’an 710064China Shaanxi Transportation Technology Consulting Co. Ltd.Xi’an 710068China School of Information Engineering Xizang Minzu UniversityXianyang 71208China

To improve the mechanical properties and durability of the cement-stabilized base,rubber particles of three different sizes and with three different contents were optimally selected,the evolution laws of the mechanical strength and toughness of rubber-particle cement-stabilized gravel(RCSG)under different schemes were determined,and the optimal particle size and content of rubber particles were *** this basis,the durability of the RCSG base was *** results show that with an increase in the rubber particle size and content,the mechanical strength of RCSG gradually decreased,whereas the toughness and transverse deformation ability gradually increased.1%content and 2–4 mm sized RCSG can better balance the relationship between mechanical strength and *** 7 d unconfined compressive strength was 17.7%higher than that of the 4–8 mm *** 28 d toughness index and ultimate splitting strain can be increased by 9.8%and 6.3 times,respectively,compared with ordinary cement-stabilized gravel(CSG).In terms of durability,compared with CSG,RCSG showed a 3.7%increase in the water stability property of cement-stabilized base with 1%content and 2–4 mm rubber particles,5.5%increase in the frozen coefficient,and 80.6%and 37.9%increase in the fatigue life at 0.70 and 0.85 stress ratio levels,respectively.

关键词： pavement materials cement-stabilized gravel rubber particles material components mechanical property durability performance

Nanocellulose/nitrogen and fluorine co-doped graphene composite hydrogels for high-performance supercapacitors

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Nano Research 2023年第7期16卷 9519-9529页

作者： Yong Zhang Qingyun zhou Wenhui Ma chaohui Wang Xuefeng Wang Jiajun chen Tiantian Yu Shan Fan College of Materials Science and Engineering Graphene Functional Materials Research LaboratoryQiqihar UniversityQiqihar 161006China College of Materials Science and Engineering Heilongjiang Province Key Laboratory of Polymeric Composition MaterialQiqihar UniversityQiqihar 161006China School of Chemistry and Chemical Engineering Qiqihar UniversityQiqihar 161006China Department of Practice Teaching and Equipment Management Qiqihar UniversityQiqihar 161006China

Three-dimensional graphene materials have been studied as typical supercapacitors electrode materials by virtue of their ultrahigh specific surface area and good ion transport ***,improvement of the poor volumetric electrochemical performance of these graphene materials has been required although they have high gravimetric energy *** this work,nanocellulose/nitrogen and fluorine co-doped graphene composite hydrogels(NC-NFGHs)were prepared through a convenient hydrothermal approach utilizing ammonium fluoride as the heteroatom ***(NC)and high concentration of graphene oxide(GO)were utilized to adjust the structure of NC-NFGHs and increase their packing ***,the aqueous symmetric supercapacitor based on NC-NFGH-80 exhibits remarkable gravimetric(286.6 F·g^(-1))and volumetric(421.3 F·cm^(-3))specific capacitance at 0.3 A·g^(-1),good rate performance,and remarkable cycle stability up to 10,000 ***,the all-solid-state flexible symmetric supercapacitors(ASSC)fabricated by NC-NFGH-80 also delivered a large specific capacitance of 117.1 F·g^(-1)at 0.3 A·g^(-1)and long service life over 10,000 cycles at 10 A·g^(-1).This compact porous structure and heteroatom co-doped graphene material supply a favorable strategy for high-performance supercapacitors.

关键词： compact graphene composite hydrogel high packing density N/F co-doping gravimetric/volumetric performances supercapacitors

Co-delivery of mitochondrial targeted lonidamine and PIN1 inhibitor ATRA by nanoparticulate systems for synergistic metastasis suppression

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Nano Research 2022年第4期15卷 3376-3386页

作者： cheng chen Qiuyi Li Liyun Xing Minglu zhou chaohui Luo Shujie Li Lian Li Yuan Huang Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial TechnologyWest China School of PharmacySichuan UniversityChengdu 610041China

Mitochondria are highly involved in the metastasis of cancer ***,tumor cells impede the efficiency of mitochondrial targeted drugs by protecting mitochondria through an intrinsic and adaptive antioxidant *** aim to disturb the redox homeostasis by prolyl-isomerase PIN1 inhibitor all-trans retinoic acid(ATRA)to improve the therapeutic efficacy of mitochondrial targeted lonidamine(TL).The combination of ATRA and TL with a ratio of 2:1 was found to have the best synergistic effect in inhibiting the proliferation and metastasis of metastatic 4T1 breast cancer ***-drug loaded nanoparticles(TL-ATRA NPs)were further developed by self-assembly and were observed to disturb the redox homeostasis drastically and triggered a robust mitochondrial disruption on metastatic 4T1 breast cancer *** molecular mechanism was related to the downregulation of nuclear factor E2-related factor 2(NRF2),a critical transcription factor that regulated antioxidant responses,and its downstream *** a result,TL-ATRA NPs significantly suppressed the growth of primary tumors and the formation of lung metastasis ***,our findings showed that sensitizing mitochondria to anti-cancer drugs by disturbing redox homeostasis achieved a satisfactory therapeutic effect to inhibit tumor growth and metastasis.

关键词： tumor metastasis mitochondrial dysfunction PIN1 inhibition redox homeostasis disruption combinatorial therapy

Open-loop and optimal control of cylinder wake via electromagnetic fields

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Chinese Science Bulletin 2008年第19期53卷 2946-2952页

作者： ZHANG Hui FAN BaoChun chen zhihua DONG Gang zhou BenMou Laboratory of Transient Physics Nanjing University of Science and Technology Nanjing 210094 China

The experimental and numerical investigations on electromagnetic control of cylinder wake have been performed in this paper. Experiments were conducted in a rotating annular tank filled with a low-conducting electrolyte. A cylinder with an electromagnetic actuator mounted on the surface was placed into the electrolyte. Force measurements have been carried out by strain gages attached to a fixed beam to which the hydrofoil is suspended and flow fields are visualized by dye markers. Based on the Navier-Stokes equations considering the electromagnetic body force, i.e. Lorentz force, in the ex- ponential-polar coordinates, the numerical investigations were carried out by means of an Alterna- tive-Direction Implicit algorithm and a Fast Fourier Transform algorithm. Experimental results have shown the same tendency with the numerical results. For the constant Lorentz forces, called open-loop control, the vortex shedding was fully suppressed. Meanwhile, the weak street disappeared and the drag force was reduced. Based on the Navier-Stokes equations, an adjoint-based ensemble optimiza- tion of control algorithms was developed and adjoint equations in the exponential-polar coordinates were derived. The equations were solved by numerical algorithm as mentioned above. The evolutions of the flow field in the control process were discussed according to the calculated variable optimal interaction parameters.

关键词：圆柱尾流电磁流最佳控制设计电磁域