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1.
1 Introduction Inthepastdecadeorso ,theexistenceofglobalat tractorsandtheestimatesoftheirHausdorffandfractaldimensionshavebeeninvestigatedfornumerousdissipa tivenonlinearpartialdifferentialequationswhichareau tonomous[1~ 4 ].Thenon autonomousinfinite dynami… 相似文献
2.
Let R be a ring, a ,b ∈ R, ( D , α ) and (G , β ) be two generalized derivations of R . It is proved that if aD ( x ) = G ( x )b for all x ∈ R, then one of the following possibilities holds: (i) If either a or b is contained in C , then α = β= 0 and there exist p , q ∈ Qr ( RC) such that D ( x )= px and G ( x )= qx for all x ∈ R;(ii) If both a and b are contained in C , then either a = b= 0 or D and G are C-linearly dependent;(iii) If neither a nor b is contained in C , then there exist p , q ∈ Qr ( RC) and w ∈ Qr ( R) such that α ( x ) = [ q ,x] and β ( x ) = [ x ,p] for all x ∈ R, whence D ( x )= wx-xq and G ( x )= xp + avx with v ∈ C and aw-pb= 0. 相似文献
3.
LU Li-gang YAN Li-tan XIANG Li-chi 《浙江大学学报(A卷英文版)》2007,8(1):158-163
INTRODUCTION Throughout this paper, we shall work with a filtered complete probability space (?,F,(Ft),P) sat-isfying the usual conditions. Let B=(Bt)t≥0 be a stan-dard Brownian motion with B0=0. Denote by ú the set of all non-negative real numbers. Recall that a diffusion process X starting at x≥0 is called the square of a Bessel process of dimension δ>0 if d X t = δd t 2 | X t |d Bt , X 0= x, (1) Clearly, this equation has a unique non-negative strong solution X, i.e., … 相似文献
4.
姜海益 《浙江大学学报(A卷英文版)》2004,5(7):754-758
Let k,m,n be positive integers,and k≥2,α∈(0,1],0<r<min {m,n} an integer,d=r (m-r)/(k α),and iff∈ Ck,α(Rm,R″),A =Cr(f)= {x ∈ Rm ,rank(Df(x))≤r},thenf(A)is d-null.Thus the statement posed by Arthur Sard in 1965 can be completely solved when k≥2. 相似文献
5.
Let Bnp={x ∈ Rn‖|x ‖p≤l} be the unit ball ofp norm in the n-dimensional normed space p. The formula for the volume of Bnp was obtained and its asymptotic properties were found out as n→∞and p→∞. 相似文献
6.
通过使用映象的广义弱交换条件,在完备度量空间中研究了更为广泛的一类压缩型映象的公共不动点的存在性,给出了一个新的公共不动点定理,从而在很大程度上改进和推广了现有文献中的一些结果. 相似文献
7.
Zhang Hanlin 《上海大学学报(英文版)》1998,2(3):191-193
1IntroductionDiferentialequationswithturningpointsexistwidelyinmanyproblemsofmathematicsphysics,sotheseproblemsareveryimporta... 相似文献
8.
ZAKHARENKO A.A. 《浙江大学学报(A卷英文版)》2007,8(4):669-674
Acoustic wave propagation in piezoelectric crystals of classes?43m and 23 is studied. The crystals Tl3VS4 and Tl3TaSe4 (43m) of the Chalcogenide family and the crystal Bi12TiO20 (23) possess strong piezoelectric effect. Because the surface Bleustein-Gulyaev waves cannot exist in piezoelectric cubic crystals, it was concluded that new solutions for shear-horizontal surface acoustic waves (SH-SAWs) are found in the monocrystals using different electrical boundary conditions such as electri- cally “short” and “open” free-surfaces for the unique [101] direction of wave propagation. For the crystal Tl3TaSe4 with coefficient of electromechanical coupling (CEMC) Ke2=e2/(C×g)~1/3, the phase velocity Vph for the new SH-SAWs can be calculated with the following formula: Vph=(Va Vt)/2, where Vt is the speed of bulk SH-wave, Vt=Vt4(1 Ke2)1/2, Va=aKVt4, aK=2[Ke(1 Ke2)1/2-Ke2]1/2, and Vt4=(C44/ρ)1/2. It was found that the CEMC K2 evaluation for Tl3TaSe4 gave the value of K2=2(Vf–Vm)/Vf~0.047 (~4.7%), where Vf~848 m/s and Vm~828 m/s are the new-SAW velocities for the free and metallized surfaces, respectively. This high value of K2(Tl3TaSe4) is significantly greater than K2(Tl3VS4)~3% and about five times that of K2(Bi12TiO20). 相似文献
9.
INTRODUCTION The problem of minimal surface is an old and active problem in the field of differential geometry. The minimal surface has been employed in many areas such as architecture, material science, aviation, ship manufacture, biology, crystallogeny, and so on. The history of minimal surface began with La- grange in 1762 (Nitsche, 1989). Many literature on the minimal surface exist in the last two hundred years (Nitsche, 1989; Osserman, 1986), but few on the minimal surface from the… 相似文献
10.
1 Introduction Singularlyperturbeddifferentialequationswithturningpointsareveryimportantformathematiciansandphysicistssincetheseproblemsexistwidelyinmanyproblemsofphysics.TheproblemswithturningpointswerestudiedbyWentzal,Kramers,Bullounin[1],Langer,A… 相似文献
11.
Surface morphologies of Zr52.5 Al10 Ni10 Cu15 Be12.5 bulk metallic glass after being rolled at both a temperature around T9 and near ( Tx - 50) K were investigated with a scanning electron microscopy. Macroscopic and microscopic observation results show that squamae, cracks, steps and wedges exist on the surface when the samples were rolled at temperatures around Ty. However, a smooth and fiat surface appears when the samples were rolled at temperatures near ( Tx - 50) K. These results indicate that the mode of deformation in the supercooled liquid region is a partially homogeneous flow at a temperature around T9, and a fully homogeneous one at temperatures near ( Tx - 50) K. According to the results, it is more feasible to roll the amorphous alloys at temperatures near ( Tx - 50) K to obtain parts with smooth and fiat surface. 相似文献
12.
S. F. Shaukat Ph. D. Ya-Ming Dong Ph. D. M. Hussain R. Farooq Guang-Yuan Li 《上海大学学报(英文版)》2002,6(1):45-49
Up-conversion processes for the blue, green and red emissions were found two-photon phenomenon, known as the cooperative phenomenon.
This phenomenon was assisted by Nd3+ → Yb3+ → Ho3+ energy transfer. The strong green emission due to the Ho3+ : (5F4, 5S2)→ 5I8 transitions was observed in Nd3+-Ho3+ co-doped ZrF4-based fluoride glasses under 800 nm excitation. As an attempt to enhance Ho3+ up-conversion luminescences in the Nd3+ – Ho3+ co-doped ZrF4-based glasses, Yb3+ ions were added to the glasses. As a result it was found that, in 800 nm excitation of 60 ZrF4. 30BaF2. (8-x)LaF3. lNdF3. xYbF3. 1HoF3 glasses (x=0 to 7), sensitized up-conversion luminescences are observed at around 490 nm (blue), 545 nm (green), and 650 nm (red), which
correspond to the Ho3+ : 5F3 → 5I8, ( 5F4, 5S2)→5I8 and 5F5→ 5I8 transitions respectively. The intensities of the green and red emissions in a 3 mol % YbF3-containing glass were about 50 times stronger than those glasses without YbF3. This is based on sensitization due to Yb3+ ions. In particular, the green emission was extremely strong and the Nd3+-Yb3+-Ho3+ co-doped ZrF4-based glasses have a high possibility of realizing a green up-conversion laser glass. In this paper the up-conversion mechanism
in the glasses is discussed in detail. 相似文献
13.
Jian Liu Jian-zhong Shentu Li-hua Wu Jing Dou Qi-yang Xu Hui-li Zhou Guo-lan Wu Ming-zhu Huang Xing-jiang Hu Jun-chun Chen 《Journal of Zhejiang University. Science. B》2012,13(5):348-355
In order to comply with the requirements for a drug listed in China, the study was developed to compare the pharmacokinetics
and relative bioavailability of two different enteric formulations of omeprazole (OPZ) in healthy Chinese subjects. A total
of 32 volunteers participated in the study. Plasma concentrations were analyzed by nonstereospecific liquid chromatography/tandem
mass spectrometric (LC-MS/MS) method. After administration of a single 40-mg dose of the two OPZ formulations, the comparative
bioavailability was assessed by calculating individual AUC0−t
(the area under the concentration-time curve from time zero to the last measurable concentration), AUC0−∞ (the area under the concentration-time curve extrapolated to infinity), C
max (the maximum observed concentration), and T
peak (the time to C
max) values of OPZ, 5-hydroxyomeprazole (OH-OPZ), and omeprazole sulfone (OPZ-SFN), respectively. The 90% confidence intervals
(CIs) of AUC0−t
, AUC0−∞, and C
max were 85.4%–99.0%/88.8%–98.6%/87.6%–99.4%, 85.5%–99.2%/89.0%–98.6%/88.5%–101.3%, and 72.3%–87.6%/79.6%–91.1%/88.4%–99.1% for
OPZ/OH-OPZ/OPZ-SFN, respectively, and T
peak values did not differ significantly. In this study, the test formulation of OPZ in fasting healthy Chinese male volunteers
met the Chinese bioequivalance standard to the reference formulation based on AUC, C
max, and T
peak. 相似文献
14.
Supersaturated solid solutions Fe1-xCx (0≤x≤0.9 ) of wide composition range have been prepared by mechanical alloying process. Nanocrystalline phase was formed for 0 ≤ x ≤ 0.67 and a large grain phase for 0.75 ≤ x ≤ 0.9. The large fraction of graphite volume puts off formation of nanocrystalline phase for high carbon content. In the large grain phase, magnetization follows simple magnetic dilution, and eoereivity He is mainly due to dissolution of carbon at grain boundaries. In the nanocrystalline phase the alloying effect of carbon is revealed by a distinct reduction of average magnetic moment. The increasing lattice constant with increasing carbon content is observed for x ≤ 0.5, suggesting that the high carbon concentration may enhance diffusion of carbon into the Fe lattice. It shows a discontinuity in the Hc variation with a grain size D of nanocrystalline phase. For small grain D below the critical value, Hc increases with D. For a large grain D, Hc decreases with increasing D. The solubility limit of carbon in a-Fe extended by nanocry- stalline phase formation is discussed. 相似文献
15.
Chemically processed Nb-doped SrTiO3 films and properties 总被引:1,自引:0,他引:1
Ming-zhi Yin 《浙江大学学报(A卷英文版)》2006,7(8):1436-1439
Homogeneous, crack-free SrNbxTi1−x
O3 thin films on (110) silicon substrates were successfully fabricated by sol-gel processing. The optimum route and conditions
were systematically investigated. Sr(OAc)2 glacial acctic acid solution, after being refluxed and reacted with tartrate, formed Sr(OAc)2(C4H6O6)2; Ti(OBu)4 formed Ti(OAc)4−x
(AcAc)x after having the ligand partially exchanged with AcAc, while Nb(OC2H5)5 formed (OAc)2Nb(AcAc) (C4H6O6) by exchanging of ligand in glacial acetic acid with (CH3CO)2O. All the metal species after undergoing partial hydrolysis and polymerization with hydroxyl or oxygen, formed SrNbxTi1−x
O13 cluster sol. Methyl cellulose (MCL) caused SrNbxTi1−x
O3 sol to have polymeric structure and easily form films. SrNbxTi1−x
O3 films with perovskite were subsequently formed after being annealed at 650∼750 °C for 60 min in 25% N2+75% H2 (volume ratio) atmosphere. Resistivity of the SrNb0.1Ti0.9O3 films at room temperature was 64 μω·cm, a particular T
2 temperature dependence of the resistivity, from 25 K up to room temperature, was observed.
Project (No. 2002CB613305) supported by the National Basic Research Program (973) of China 相似文献
16.
给出了一类广义KANNAN型压缩映象及其不动点定理 ,推广并改进了文 [1- 6 ]的一些重要结果。 相似文献
17.
In this paper, the author proves that theL
p-boundedness of the Marcinkiewicz integral μΩ on product domainsR
n×Rm; for Ω∈(1)∩(5) improves the result of Chen et al. (2000).
Project supported by Major Project of NSFC (No.19631080) and NSF of Zhejiang province (No. RC97017). 相似文献
18.
Well-cubic perovskite lanthanum aluminate (LaAlO3) film on (110) silicon substrate was fabricated by sol-gel method with corresponding inorganic salts. Lanthanum acetate and
aluminum acetate glacial acetic acid solutions were prepared via ligand exchange starting from lanthanum nitrate hexahydrate
and aluminum nitrate hexahydrate after being refluxed. (CH3CO)2O removed nitrates and the crystallized H2O completely, acetylacetone (AcAc) was partially bidentated with metallic ion of the metallic acetates and formed La(OAc)3−x
(AcAc)
x
which were hydrolyzed into La(AcAc)3−x(OH)
x
by adding 10 ml 0.4% methyl cellulose (MCL) solution. The La(AcAc)3−x
(OH)
x
, polymerizing and combining with MCL, formed the LaAlO3 sol precursor with heteropolymeric structure and formed film easily. The epitaxial LaAlO3 film on Si(110) substrate was crystallized after being annealed in thermal annealing furnace for 650–750 °C/30 min. The morphologies
and microstructures were characterized. The refractive index of the LAO film was 1.942 to 2.007; the dielectric constant and
the dissipation factors were estimated to be 23–26 and 2.1×10−4−2.4×10−4 respectively.
Project (No. 2002CB613305) supported by the National Basic Research Program (973) of China 相似文献
19.
蒋岳祥 《浙江大学学报(A卷英文版)》2004,5(3):335-342
Suppose {Xi,i≥1} and {Yi, i≥1} are two independent sequences with distribution functions and , respectively. Zi,n is the combination of Xi and Yi with a probability for each I with 1≤ i≤n. The extreme value distribution GZ(x) of this particular triangular array of the i.i.d. Random variables Z1,n,… Z2,n, Zn,n is discussed. We found a new form of the extreme value distributions i)ΦAα1(x)Φα2 and ii) ψAα(x)ψα2(x)α1<α2), which are not max-stable. It occurs if FX and FY belong to the same MDA(Φ) or MDA(Ψ). 相似文献
20.
To assess the influence of cyclosporin A (CsA) and tacrolimus (FK506) on mycophenolic acid (MPA) and correlation analysis
of the pharmacokinetic parameters and patient characteristics, clinical outcome in Chinese kidney transplant recipients, the
pharmacokinetics of 1000 mg mycophenolate mofetil (MMF) twice daily was measured by high-performance liquid chromatography
(HPLC). PKS (Pharmaceutical Kinctics Software) 1.0.2 software package was used for the calculation of pharmacokinetic parameters.
The meanC
max,t
max, and AUC(0–12) were (21.88±10.52) μg/ml, (1.20±0.95) h, and (52.546±13.215) μg·h/ml, respectively. The level of AUC(0–12) in the FK506 group was significantly higher than that in the CsA group. MPA appeared not to be affected by renal function.
MPA AUC(0–12) showed statistically significant difference according to the patient's gender.
Project (No. 20040462) supported by the Foundation of Education Bureau of Zhejiang Province, China 相似文献