脉冲中立型时滞抛物偏微分方程组的振动准则

考虑一类脉冲中立型时滞抛物偏微分方程组解的振动性,利用一阶脉冲时滞微分不等式获得了该类方程组在Robin,Dirichlet边值条件下所有解振动的若干充分条件.所得结果充分反映了脉冲和时滞在振动中的影响作用.     

OSCILLATION THEOREM TO SYSTEMS OF IMPULSIVE NEUTRAL DELAY PARABOLIC PARTIAL DIFFERENTIAL EQUATIONS

In this paper,we study the oscillation of solutions to the systems of impul- sive neutral delay parabolic partial differential equations.Under two different boundary conditions,we obtain some sufficient conditions for oscillation of all solutions to the systems.     

反相高效液相色谱法测定尿中α-萘酚、β-萘酚、对硝基酚和间硝基酚

利用反相高效液相色谱法建立了同时检测人尿样中的α-萘酚、β-萘酚、对硝基酚和间硝基酚的新方法。采用DiamonsilTMC18（150mm×4.6mm,5μm）色谱柱分离,以V（甲醇）∶V（乙酸铵缓冲液）=58∶42为流动相,流速为0.75mL/min,柱温为35℃,于波长280nm处检测。当α-萘酚、β-萘酚、对硝基酚和间硝基酚的浓度分别在0.120—19.44、0.106—19.44、0.479—27.80μg/mL和0.439—27.80μg/mL范围内与峰面积呈良好线性关系,RSD分别为3.7%—4.3%、2.4%—3.6%、2.7%—4.9%和2.9%—3.6%（n=5）。本法用于尿中4种物质的同时测定,回收率分别为98.8%、103.8%、97.5%和105.0%,结果满意。     

QUALITATIVE ANALYSIS OF BOBWHITE QUAIL POPULATION MODEL

In this paper, the qualitative behavior of solutions of the bobwhite quail pop-ulation modelwhere 0   

Synthesis,Crystal Structure and Thermal Stability Properties of the Supramolecular Complex [Co（phen）3][（C6H5）2C（OH）COO]2·7H2O

One new cobalt complex [Co（phen）3][（C6Hs）2C（OH）COO]2·7H2O with benzeneacetic acid （BAA）, 1,10-phenanthroline and cobaltous perchlorate has been synthesized by means of solvent method. It crystallizes in the triclinic system, space group P^-1, with a = 1.14181（13）, b = 1.64417（18）, c = 1.65342（18） nm, α = 74.2830（10）, β= 84.4490（10）, γ = 74.9430（10）°, V = 2.8842（6） nm^3, Dc = 1.359 g/cm^3, Z = 2, F（000） = 1234, R = 0.0621 and wR = 0.1673. The crystal structure shows that the cobalt ion is coordinated with six nitrogen atoms from three 1,10-phenanthroline molecules, giving a distorted octahedral coordination geometry. There are a lot of hydrogen bonds in the complex, from which a two-dimensional network is constructed. The result of TG analysis shows that the title complex is stable below 130.0 ℃.     

双环[2.2.1]-2-庚烯-5，6-二甲酸镍配合物的合成、晶体结构及热稳定性

The nickel complex Ni(phen)(H₂O)₃[C₈H₁₁O₂(COO)] has been synthesized with bicycle[2.2.1]hept-2-en-5,6-dicarboxylic acid [C₇H₈(COOH)₂] by means of solvent way. It crystallizes in the triclinic space group P1, with a=0.780 58(16) nm, b=1.189 9(2) nm, c=1.214 8(2) nm, α=66.20(3)°, β=88.28(3)°, γ=86.33(3)°, V=1.030 3(4) nm³, D_c=1.554 g·cm^-3, Z=2, F(000)=502. Final GOF=1.107, R₁=0.026 4, wR₂=0.070 2. The crystal structure shows that the nickel ion is coordinated with four oxygen atoms from one bicycle[2.2.1]-2-hepten-5,6-dicarboxylic acid molecule and three water molecules, respectively, with two nitrogen atoms from the 1,10-phenanthroline molecule, forming a distorted octahedral coordination geometry. The result of TG analysis shows that the title complex was stable under 210.0 ℃. CCDC: 741933.     

Global Existence of Positive Periodic Solutions for a Distributed Delay Competition Model

By using the continuation theorem of Mawhin's coincidence degree theory, a sufficient condition is derived for the existence of positive periodic solutions for a distributed delay competition modelwhere ri and r2 are continuous w-periodic functions in R+=[0,∞) with ,ai,ci(i =1,2) are positive continuous w-periodic functions in R+=[0,∞),bi (i = 1,2) is nonnegative continuous w-periodic function in R+=[0,∞), w and T are positive constants. Ki,Lt ∈ C([-T,0], (01 88)) and Ki(s)ds = 1,ds - 1. i = 1,2. Some known results are improved and extended.     

Morphology and oxidation of Zr-based amorphous alloy ablated by femtosecond laser pulses

Femtosecond laser ablation of an amorphous alloy in air, including single-pulse ablation, multi-pulse drilling and trenching has been investigated. Laser-induced ablation and related effects were examined by means of scanning electron microscopy, energy dispersive X-ray analysis, transmission electron microscopy and electron diffraction. Oxidation was observed in the multi-pulse ablation region surface. With selected parameters, molten trace, spatter and crystallization can be avoided in the vicinity of the machining area. The results show that femtosecond laser ablation with selected parameters is a promising method for micromachining amorphous alloys. PACS 79.20.Ds; 87.80.Mj; 81.05.Bx; 81.65.Mq; 61.82.Bg     

Periodic Bifurcation and Soliton Deflexion for Kadomtsev-Petviashvili Equation

The spatial-temporal bifurcation for Kadomtsev-Petviashvili （KP） equations is considered. Exact two-soliton solution and doubly periodic solution to the KP-I equation, and two classes of periodic soliton solutions in different directions to KP-Ⅱ are obtained using the bilinear form, homoclinic test technique and temporal and 1 spatial transformation method, respectively. The equilibrium solution uo =-1/6, a unique spatial-temporal bifurcation which is periodic bifurcation for KP-I and deflexion of soliton for KP-Ⅱ, is investigated.     

Global behavior for a fourth-order rational difference equation

In this paper, we use a method different from the known literature to investigate the global behavior of the following fourth-order rational difference equation: