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1.
Introduction Over the past twenty years the static push-over proce- dure has been presented and developed by several au- thors, including Saiidi and Sozen[1], Fajfar and Gasper- sic[2], Bracci et al.[3], amongst others. This method is also described and r…  相似文献   

2.
In this paper, we study the decay rates of the generalized Benjamin–Bona–Mahony equations in n-dimensional space. By using Fourier analysis for long wave and by applying the energy method for short wave, we obtain the Hm convergence rates of the solutions when the initial data are in the bounded subset of the phase space Hm(Rn)(n3). The optimal decay rates are obtained in our results and are found to be the same as the Heat equation.  相似文献   

3.
Colonization of periphytic ciliates and their usefulness for monitoring water quality were evaluated using the glass slide method in two enclosed mariculture ponds used to culture crab larva and in a natural seawater reservoir. The results revealed that (1) the ciliate species composition and colonizing process differed between the culturing ponds and the natural reservoir and (2) the dominant ciliate species showed a greater distribution in terms of both the abundance and the occurrence frequency. This study also demonstrated that structural parameters were strongly related to water conditions. For example, the abundance was positively associated with and soluble reactive phosphate (P < 0.05), whereas the species number, species diversity and evenness were negatively correlated with nutrients (e.g. and NH3–N) and temperature (P < 0.05). These findings support the evidence that periphytic ciliates are useful bioindicators of water quality in enclosed mariculture ecosystems.  相似文献   

4.
Compressibility of a natural kyanite to 17.5 GPa   总被引:1,自引:0,他引:1  
The compressional behaviour of a natural kyanite, (Al1.99Fe0.01)SiO5, has been investigated to about 17.5 GPa at 300 K using a diamond-anvil cell and synchrotron X-ray diffraction. The pressure–volume data fitted to the third-order Birch–Murnaghan equation of state (EoS) yield an isothermal bulk modulus (K0T) of 192 ± 6 GPa and pressure derivative () of 6 ± 1. When is fixed as 4, the derived K0T is 201 ± 2 GPa. These values are in excellent agreement with most experimental determinations in the literature. Consequently, it can be concluded that the compressibility of kyanite under high pressures has been accurately constrained.  相似文献   

5.
We examined the effect of excessive Internet use on the time–frequency characteristic of the electroencephalogram by wavelet transformed and non-negative matrix factorization (NMF). The event-related potentials (ERP) of normal subjects and excessive Internet users were acquired using the oddball paradigm experiment. We applied the wavelet transformed and event-related spectral perturbation to ERP in order to extract the time–frequency values. The F-test statistics of time–frequency values were then decomposed into two components by NMF. Excessive Internet use resulted in a significant decrease in the P300 amplitudes (P < 0.05) and a significant increase in the P300 latency (P < 0.05) in all electrodes. The major effect of excessive Internet use on gamma oscillation occurred at 300 ms after stimuli at 40–50 Hz on the parietal central region. Thus, these data suggest that excessive Internet use affects information coding and integration in the brain.  相似文献   

6.
偶数阶非线性中立型阻尼微分方程的振动性与渐近性   总被引:1,自引:1,他引:0  
 考虑以下偶数阶非线性中立型阻尼微分方程的振动性与渐近性:[x(t)+ (t)x(τi(t))](n)+b(t)[x(t)+ (t)x(τi(t))](n-1)+q(t)f(x(σ(t)))=0,t≥t0,获得了该类方程所有解振动的2个准则,推广了现有文献的一些结果.此外,还获得了关于该类方程每一个有界解的振动性与渐近性的2个充分条件.  相似文献   

7.
LiFePO_4@multiwalled carbon nanotubes(LFP@MWCNTs) nanocomposite has been fabricated using risedronic acid(RDA) as a new eco-friendly phosphorus source. Microscopic, spectroscopic, and electrochemical characterization demonstrate that the MWCNTs are in the form of coiled and cross-linking nanoribbon, which wrapped and encrusted around LiFePO_4 particles to form a three-dimensional(3D) nano-network composite.This microstructure of 3D nano-network is obtained due to the reactions between RDA's special functional groups with Fe~(2+) and C-OH,-C=O or-COOH on the surface of the functionalized MWCNTs. The results also show that the particle size of the fabricated LiFePO_4@MWCNTs composite is below 300 nm with the pure crystal of olivine. This nanocomposite indicates an enhanced reversible capacity of 162.2 mAh g~(-1) at 0.2C, and high capacity retention of 76.5% even at 10C after the 800 th cycles. The electric conductivity and Li~+ diffusion coefficient(D_(Li)~+) of the LiFePO_4@MWCNTs are 3.79 × 10~(-2)S cm~(-1) and 4.46 × 10~(-11) cm~2s~(-1), respectively.These improved electrochemical parameters can be attributed to the nano-sized effect of particles, MWCNTs' wrapping effect and 3D nano-network microstructure of the LFP@MWCNTs resulted from using RDA as a new phosphorus source.  相似文献   

8.
Some limit theorems for weighted sums of random variable fields   总被引:1,自引:0,他引:1  
1Preliminaries DuringthelastyearsthereappearedquiteafewpapersaboutlimittheoremsforBanachspacevaluedrandomvariables(r.v.’s)withmultidimensionalindex.Itistheaim ofthispapertogivecomparativeweakconditionswhichimply limittheoremsforweightedsumsofBanachspacevaluedr.v.fields.Thecurrentworkextendsthecorrespondingresultsof Refs.[15].Westartwithsomenotationsanddefinitions.LetNdbe thesetofalld dimensionallatticeofpointswithpositiveinte gersascomponents,whered≥1isafixedinteger.LetNdbe equippedwithco…  相似文献   

9.
Let (t)(tR + N ) be the d-dimensional N-parameter generalized Brownian sheet. We study the polar sets for (t). It is proved that for any aR d , P{ (t) = a, for some tR > N } = and the probability that (t) has k-multiple points is 1 or 0 according as whether 2kN > d(k − 1)β or 2kN < d(k−1)α. These results contain and extend the results of the Brownian sheet, where R > N = (0,+∞) N ,R + N =[10,+∞) N ,0< α≤1 and β≥1. Biography: LI Huiqiong (1966–), female, Associate professor, research direction: stochastic process and random fractal.  相似文献   

10.
It is well known that, the singular integral operatorS defined as: ifL is a closed smooth contour in the complex plane C, thenS is a bounded linear operator fromH μ(L) intoH μ(L): ifL is an open smooth curve, thenS is just a linear operator fromH * intoH *. In this paper, we define a Banach space , and prove that is a bounded linear operator, then verify the boundedness of other kinds of singular integral operators. Supported by the National Science Foundation of China Wang Xiaolin: born in Aug. 1950, Professor  相似文献   

11.
0 IntroductionLeqtuiliHnebaer afo rHimlbaenrtd sap baoceun.dLeedtlianaenardfufnbceti oan baolu onndeHd ,serse--spectively. Our goal is to seekv∈Hsuchthata(u,v) =f(u) , u∈ H (1)As a rule, we call the expression (1) a variational equationandva solutiontothis equation.By virtue of the Riesz repre-sentationtheorem,there exists a uniquely determined boundedlinear operatorA:H→Hsuchthata(u,v) =〈u,Av〉, u,v∈ H,where〈·,·〉is the inner product onH.If the sesquilinearformais also with posit…  相似文献   

12.
Using the solubility method, the solubility of CuCl2 in liquid-undersaturated HCl-bearing water vapor was investigated experimentally at temperatures of 330-370 ℃ and pressures of 4.2-10 MPa. The re-sults have shown that hydration could significantly enhance copper solubility and the concentrations of copper were positively correlated with PH2O. The solubility of copper in vapor phase increased with increasing PH2O at the constant temperature. CuCl2 was transported as hydrated species CuCl2(H2O)ngas in water vapor. The formation of complexes is proposed to be the result of the following reaction: CuCl2solid nH2Ogas = CuCl2 (H2O)ngas The hydration number n decreased slightly with increasing temperature. Statistical hydration numbers are 4.0, 3.6 and 3.3 at 330, 350 and 370 ℃ , respectively.  相似文献   

13.
A diagnostic formula of magnetic field strength of gyrosynchrotron radiation regions of the lower harmonics (5 ≤S≤10 ) is presented based on their emissivity η νBN , absorptivity κ νBN , and the turnover frequency of radio spectra ν P. Their diagnostic error is estimated. And an accurate relation between electron energy spectral index δ and brightness temperature spectral index β is also given.  相似文献   

14.
In this paper, the oxidative degradation of 2, 4-dichlorophenoxyacetic acid (2, 4-D) using Mn2+/H2O2 reagent under UV irradiation was studied. The results show that 2, 4-D was degraded more completely in Mn2+/H2O2 solution than traditional Fenton solutions. The effects of the concentration of Mn2+, H2O2 and pH were also investigated. And under the optimal condition of 1.48×10−4 mol/L, 8.99×10−5 mol/L and pH 3.38, the formation of ·OH was the most, both the decomposition rate of H2O2 and the degradation rate of 2, 4-D were the fastest. In addition, the photoreaction process was monitored using spin-trapping electron paramagnetic resonance (EPR), and the results indicated that the oxidative process was predominated mainly by the hydroxyl radical (·OH) gennerated in the system. Biography: HUANG Yingping (1964–), Professor, Ph. D., research direction: pollution ecology and water pollution control.  相似文献   

15.
A mathematical model formulated as ΔfHθm(g)=a+sum from i=1 to 5bipi(i≠2) was constructed for the relationshipbetween standard formation enthalpy ΔfHθm(g) and path index Pi of substituted benzenes derivatives. An empiric equation for the calculation of ΔfHθm(g) was worked out. The calculated values of standard formation enthalpy based on this model are excellently consistent with those from experimental for 55 organic compounds. The model is shown to be simple and of practical usefulness, particularly when required experimental data are unavailable.  相似文献   

16.
The Raman and IR spectra of LnTPPTS·10H2O [Ln=La,Sm, TPPTS=P(m-C6H4SO3) 3 3− ] complexes are reported. Based on the observed Raman and IR characteristic frequencies, a vibrational assignments has been made for these complexes. Coordination induces a lengthening of the S−O bonds and a shortening of the C−S bond. The C−S stretching frequencies should therefore increase while the position of the should move to a lower wavenumber. Vibrational modes of metal-oxygen polyhedron V (La-O) at 146, 168,253 cm−1 are the structural charactrization for coordinate bond of LnTPPTS complexes. Chen Zhenhua: Born in 1938, Professor  相似文献   

17.
0 IntroductionIntheprocessofR&Ditem ,thereisusuallycompetition .ManyfirmswanttoinvestR&Dtoobtainapatent.Lury[1 ] gaveanequilibriuminvestmentundertheconditionofone timeinvestmentandcontinuousinvestmentwhenthepayoffwasafixedprize.Ref.[2 ]analyzedtheeffectofinformationsharinginR&D .TherearemanyliteraturesaboutanalysisofR&DlevelswhenfirmscompeteinoutputmarketafterR&Dsucceeds[3 ,4] .Additionally ,todecideinvestmentlevel,therearemanyliteraturesaboutR&Ditem’spricing .MondherBellalah[5] ,K .…  相似文献   

18.
A novel advanced oxidation process——wet electrocatalytic oxidation (WEO) was studied with p-nitrophenol as model pollutant and β-PbO2 electrode as the anode. Compared with the effect of the individual wet air oxidation (WAO) and electrochemical oxidation (EO), the effect of WEO showed syn- ergistic effect on COD removal under the conditions of temperature 160℃, C=1000 mg·L-1, PN2=0.50 MPa, PO2=0.9 MPa, current density = 3 mA·cm-2, Na2SO4 3 g·L-1. And the synergistic factor got the best value of 0.98 within 120 min after 180 min treatment. The synergistic factor was studied after 120 min treatment at 100℃, 120℃, 140℃ and 160℃, and the effect of 120℃ was the best with the value of 1.26. Possible mechanism for the synergistic effect was discussed based on the analysis of free-radical generation and intermediates detected by HPLC and GC/MS.  相似文献   

19.
The boundary value problem for harmonic maps of the Poincare disc is discussed. The emphasis is on the non-smoothness of the given boundary values in the problem. Let T . be a subspace of the universal Teichmüller space, defined as a set of normalized quasisymmetric homeomorphisms h of the unit circle S onto itself where h admits a quasiconformal extension to the unit disc D with a complex dilatation μ satisfying where ρ(z)|dz|2 is the Poincare metric of D. Let B . be a Banach space consisting of holomorphic quadratic differentials φ in D with norms It is shown that for any given quasisymmetric homeomorphism h : S1→S1∈ T . , there is a unique quasiconformal harmonic map of D with respect to the Poincare metric whose boundary corresponding is h and the Hopf differential of such a harmonic map belongs to B .  相似文献   

20.
A branching model {Z n} n≥0is considered where the offspring distribution of the population's evolution is not only dependent on the population size, but also controlled by a Markovian environmental process {ξ n} n≥0. For this model, asymptotic behaviour is studied such as limn→∞Z n and limn→∞Z n/m n in the case that the mean m k, θof the offspring distribution converges to m>1 as the population size k grows to ∞. In the case that {ξ n} n≥0is an irreducible positive recurrent Markov chain, certain extinction (i.e. P(Z n=0 for some n)=1) and noncertain extinction (i.e. P(Z n=0 for some n)<1) are studied.  相似文献   

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