检索结果-南通市图书馆

On the variational principle for the topological pressure for certain non-compact sets

在线全文

学校读者我要写书评

暂无评论

science china Mathematics 2010年第4期53卷 1117-1128页

作者： PEI Yu 1 & CHEN ErCai 1,2,1 Department of Mathematics,nanjing Normal university,nanjing 210097,china 2 center for nonlinear science,nanjing university,nanjing 210093,china Department of Mathematics Nanjing Normal University Nanjing China center for nonlinear science Nanjing University Nanjing China

Let (X,d,T) be a dynamical system,where (X,d) is a compact metric space and T:X → X is a continuous *** assume that the dynamical system satisfies g-almost product property and the uniform separation *** compute the topological pressure of saturated sets under these two *** the uniform separation property does not hold,we compute the topological pressure of the set of generic *** give an application of these results to multifractal analysis and finally get a conditional variational principle.

关键词： uniform separation property g-almost product property topological pressure of non-compact sets variational principle BS-dinmension

Study on the thermal stability and electrical properties of the high-k dielectrics (ZrO_2) _x(SiO_2)_(1-x)

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2009年第8期52卷 2222-2226页

作者： Lü ShiCheng1,2, YIN Jiang1,2, XIA YiDong2,3, GAO LiGang2,3 & LIU ZhiGuo2,3 1 Department of Physics, nanjing university, nanjing 210093, china 2 National Laboratory of Solid Sate Microstructures, nanjing university, nanjing 210093, china 3 Department of Materials science and Engineering, nanjing university, nanjing 210093, china Department of Physics Nanjing University Nanjing China National Laboratory of Solid Sate Microstructures Nanjing University Nanjing China Department of Materials science and Engineering Nanjing University Nanjing China

(ZrO2)x(SiO2)1-x (Zr-Si-O) films with different compositions were deposited on p-Si(100) substrates by using pulsed laser deposition technique. X-ray photoelectron spectra (XPS) showed that these films remained amorphous after annealing at 800℃ with RTA process in N2 for 60 s. The XPS spectra indi- cated that Zr-Si-O films with x=0.5 suffered no obvious phase separation after annealing at 800℃, and no interface layer was formed between Zr-Si-O film and Si substrate. While Zr-Si-O films with x >0.5 suffered phase separation to precipitate ZrO2 after annealing under the same condition, and SiO2 was formed at the interface. To get a good interface between Zr-Si-O films and Si substrate, Zr-Si-O films with bi-layer structure (ZrO2)0.7(SiO2)0.3/(ZrO2)0.5(SiO2)0.5/Si was deposited. The electrical properties showed that the bi-layer Zr-Si-O film is of the lowest equivalent oxide thickness and good interface with Si substrate.

关键词： high-k dielectric film pulsed laser deposition pseudo ternary alloy

(1.2)INVERSES OF OPERATORS BETWEEN BANACH SPACES AND LOCAL CONJUGACY THEOREM

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 1999年第1期20卷 57-62页

作者： MA JIPU(Department of Mathematics,nanjing university,nanjing 210093,china) Department of Mathematics Nanjing University Nanjing 210093 China

Let E and F be Banach spaces and f non-linear C1 map from E into F. The main result isTheorem 2.2, in which a connection between local conjugacy problem of f at x0E and a localfine property of f'(x) at x0(see the Definition 1.1 in this paper) are obtained. This theoremincludes as special cases the two known theorems: the finite rank theorem and Berger's Theoremfor non-linear Fredholm operators. Moreover, the thcorem gives rise the further results for somenon-linear semi-Fredholm maps and for all non-linear semi-Wedholm maps when E and F areHilbert spaces. Thus Theorem 2.2 not only just unifies the above known theorems but alsoreally generalizes them.

关键词： nonlinear semi-Fredholm maps Conjugacy problem Banach space

Quantitativ　estructure－activity　relationships　for　studying　alkyl（1－phenylsulfonyl）　cycloalkane－carboxylates

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental sciences 1996年第2期8卷 157-166页

作者： He Yibing Wang Liansheng (Department of Environmental science and Engineering, nanjing university, nanjing 210093, china) Department of Environmental science Nanjing University Nanjing 210093 China

Octanol/water partition coefficients,adsorption coefficients for soils and sediments and acute toxicities to Daphnia magna of 28 alkyl (1-phenylsulfonyl) cycloalkane-carboxylates were measured. These properties were correlated by linear solvation energy relationship (LSER) and chromatographic retention data determined by reverse-phase high performance liquid chromatography (RP-HPLC). The accuracy and range of applicability of these two quantitative structure-activity relationship (QSAR) methods were compared in this paper.

关键词： alkyl (1-phenylsulfonyl) cycloalkane-carboxylates LSER R-PHPLC.

Formation flying in elliptic orbits with the J_2 perturbation

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2012年第11期12卷 1563-1575页

作者： Xi-Yun Hou, Yu-Hui Zhao and Lin Liu School of Astronomy and Space science, nanjing university, nanjing 210093, china Institute of Space Environment and Astrodynamics, nanjing university, nanjing 210093, china School of Astronomy and Space science Nanjing University Nanjing 210093 China Institute of Space Environment and Astrodynamics Nanjing University Nanjing 210093 China

Relative dynamics between the chief satellite and the deputy ones in for- marion flying is crucial to maintaining the formation. A good choice of the forma- tion usually requires a lower control frequency or less control energy. For formation flying missions in highly elliptic orbits, the well-known C-W equation is not accu- rate enough. Instead, Lawden＇s equation is often used. First, the solution to Lawden＇s equation with a very simple form is deduced. Then the J2 perturbation is added. It is found that Lawden＇s solution is not necessarily valid when the J2 perturbation is con- sidered. Completely discarding Lawden＇s solution and borrowing the idea of mean orbit elements, two rules to initialize the formation are proposed. The deviation speed is greatly reduced. Different from previous studies on the J2 perturbation, except for the relatively simple expression for the semi-major axis, the tedious formulae of the long period terms and the short period terms of other orbital elements are not used. In addition, the deviation speed is further reduced by compensation of the nonlinear effects. Finally, a loose control strategy of the formation is proposed. To test the ro- bustness of this strategy, a third body perturbation is added in numerical simulations.

关键词： celestial mechanics

Preparation and Characterization of Nanocomposite MgFe_2O_4/SiO_2

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of Technology(Materials science) 2009年第3期24卷 354-358页

作者：徐莉 College of science Nanjing Forestry University

Nanocomposites MgFe2O4/SiO2 were successfully synthesized by the sol-gel method in the presence of N, N-dimethylformamide （DMF）. The formation of pure MgFe2O4 was confirmed by powder X-ray diffraction （XRD） and electron diffraction. The structural evolution of MgFe2O4 nanocrystals was followed by powder X-ray diffraction and IR absorption spectroscopy. The formation of spinel structure of MgFe2O4 started at 800 ℃, and completed at 900 ℃, The transmission electron microscopy （TEM） measurements suggest that the particle sizes increase with the increasing annealing temperature, and the mean particle sizes of the spherical samples annealed at 800 ℃, 900 ℃ and 1 050 ℃ are ca. 3 nm, 8 nm and 11 nm, respectively. Magnetization measurements at room temperature and 78 K indicate supemaramagnetic nature of these MgFe2O4 nanocrvstals.

关键词： nanocomposite sol-gel magnesium ferrite magnetic property

One-step estimation for varying coefficient models

在线全文

学校读者我要写书评

暂无评论

science china Mathematics 2005年第2期48卷 198-213页

作者： TANG Qingguo & WANG Jinde Department of Mathematics, nanjing university, nanjing 210093, china Institute of sciences, PLA university of science and Technology, nanjing 210007, china Department of Mathematics Nanjing University Nanjing China Institute of sciences PLA University of Science and Technology Nanjing China

A one-step method is proposed to estimate the unknown functions in the varying coefficient models, in which the unknown functions admit different degrees of smoothness. In this method polynomials of different orders are used to approximate unknown functions with different degrees of smoothness. As only one minimization operation is employed, the required computation burden is much less than that required by the existing two-step estimation method. It is shown that the one-step estimators also achieve the optimal convergence rate. Moreover this property is obtained under conditions milder than that imposed in the two-step estimation method. More importantly, as only one minimization operation is employed, the full asymptotic properties, not only the asymptotic bias and variance, but also the asymptotic distributions of the estimators can be derived. The asymptotic distribution results will play a key role for making statistical inference.

关键词： varying coefficient model, one-step estimation, asymptotic distribution, optimal convergence rate.

Rank theorems of operators between Banach spaces

在线全文

学校读者我要写书评

暂无评论

science china Mathematics 2000年第1期43卷 1-5页

作者： MA JipuDepartment of Mathematics, nanjing university, nanjing 210093, china Department of Mathematics Nanjing University Nanjing China

LetE andF be Banach spaces, andB(E,F) all of bounded linear operators onE intoF. LetT 0 ∈B( E,F) with an outer inverseT 0 # ∈B( F,E). Then a characteristic condition ofS=(I + T0 # (T-T0)-1 T0 # with T∈B(E, F) and ... 详细信息

关键词： rank theorem generalized inverse operator-value map.

EIT waves and coronal magnetic field diagnostics

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2009年第11期52卷 1785-1789页

作者： CHEN PengFei Department of Astronomy, nanjing university, nanjing 210093, china Department of Astronomy Nanjing University Nanjing China

Magnetic field in the solar lower atmosphere can be measured by the use of the Zeeman and Hanle effects. By contrast, the coronal magnetic field well above the solar surface, which directly controls various eruptive phenomena, can not be precisely measured with the traditional techniques. Several attempts are being made to probe the coronal magnetic field, such as force-free extrapolation based on the photospheric magnetograms, gyroresonance radio emissions, and coronal seismology based on MHD waves in the corona. Compared to the waves trapped in the localized coronal loops, EIT waves are the only global-scale wave phenomenon, and thus are the ideal tool for the coronal global seismology. In this paper, we review the observations and modelings of EIT waves, and illustrate how they can be applied to probe the global magnetic field in the corona.

关键词： coronal mass ejections (CMEs) magnetic field diagnostics magnetohydrodynamics (MHD)