The escaping disaster: A problem related to state-dependent delays

We study a second order state-dependent delay equation with an in general unbounded delay that describes an idealized one-dimensional motion. Although governed by a negative feedback mechanism, the set of equilibria, formed by the so called constant velocity solutions, is unstable and a new kind of instability, called the escaping instability, evolves.     

高阶Bernoulli数的递推公式及其应用

给出了高阶Bernoulli数的一个递推公式和Nrlund数的一个计算公式,推广了Namias[4],Deeba和Rodriguez[5],Tuenter[6]的结果.     

Some identities and congruences involving a certain family of numbers

In this paper, the authors establish several identities and congruences involving a certain family of numbers associated with the familiar Bernoulli and Euler numbers, the Stirling numbers of the first and second kind, and the central factorial numbers.     

过硫酸铵作氧化剂I2-CCl4萃取光度法测定矿石中的锰

本文根据过硫酸铵将矿样分解后的锰 (Ⅱ )氧化至锰 (Ⅶ ) ,高锰酸根与碘化钾反应析出碘 ,据此建立了碘 四氯化碳萃取光度法间接测定锰的方法。锰含量在 0 0 0 1～ 0 1mg·L- 1 之间 ,遵守比耳定律 ;对测定条件作了考察 ,通过方法的回收率试验以及与其他测定方法进行比较得到了满意的结果 ,回收率在 97%～ 10 3%之间。     

HIGHER ORDER MULTIVARIABLE NRLUND EULER-BERNOULLI POLYNOMIALS

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｋｔｈｏｒｄｅｒＮ ｒｌｕｎｄＥｕｌｅｒｐｏｌｙｎｏｍｉａｌｓＥ(ｋ)ｖ (ｘ｜ω1,… ,ωｋ)ａｎｄＢｅｒｎｏｕｌｌｉｐｏｌｙｎｏｍｉａｌｓＢ(ｋ)ｖ (ｘ｜ω1,… ,ωｋ)ａｒｅｇｉｖｅｎｂｙｔｈｅｆｏｌｌｏｗｉｎｇｅｘｐａｎｓｉｏｎｆｏｒｍｕｌａｒｅｓｐｅｃｔｉｖｅｌｙ[1]2 ｋｅｘｔ(ｅω1 ｔ+ 1 )… (ｅωｋｔ+ 1 ) = ∞ｖ=0Ｅ(ｋ)ｖ (ｘ｜ω1,… ,ωｋ) ｔｖｖ!,( 1 )ω1…ωｋｔｋｅｘｔ(ｅω1 ｔ-1 )… (ｅωｋｔ-1 ) = ∞ｖ=0Ｂ(ｋ)ｖ (ｘ｜ω1,… ,ωｋ) ｔｖｖ!. ( 2 )Ｃｌｅａｒｌｙｔ…     

Oscillation criteria for second order nonlinear differential equation with damping

1IntroductionandProblem Thefollowingisthesecondordernonlineardifferentialequationwithdamping: [p(t)ψ(y)u(y′)]′ r(t)y′(t) q(t)f(y)g(y′)=0(t≥t0),(1) inwhich,p(t)∈C′([t0,∞),(0,∞)),r(t)∈C([t0,∞),(-∞,∞)),q(t)∈C([t0, ∞),[0,∞))withtheexistenceofT≥t0,q(t)≠0,t∈[T,∞),f(y),g(y),ψ(y),u(y) ∈C((-∞,∞),(-∞,∞)),andyf(y)>0,yu(y)>0,y≠0. Thesolutiony(t)ofEq.(1)iscallednormalsolutionify(t)isthenon_constantsolutionof Eq.(1)andsupt≥t0｜y(t)｜>0(refertoRef.[1]).Anormalsolutionisoscill…     

复方丹参片生产中丹酚酸B的快速测定

为建立制药企业在生产复方丹参片时的快速质量控制方法,用TLC及反相HPLC法,对在不同处理条件下的复方丹参片样品中丹酚酸B进行了定性、定量分析,同时优化了色谱条件,提高了测定的准确性。结果表明,甲醇超声处理复方丹参片粉末20 min(1次),再用高纯水超声处理20 min(2次);流动相V(甲醇) V(乙腈) (V甲酸) V(水)=25 10 1 64,波长286 nm。本法线性好,准确度高,简便快捷经济,可用于生产该药的内在质量监测。     

关于(余)反射的范畴性质及其应用

本文研究了（余）反射的范畴性质及应用，得到的主要结果如下：（１）余反射余代数范畴和反射代数范畴是等价的．（２）反射和余反射都具有可扩张性．使用这些结果可以用来推广和化简了［１—４］等人的部分工作．     

二阶非线性微分方程解的Sturm比较定理

本文首先建立二个微分恒等式，然后利用它们研究了二类非线性微分方程与线性微分程之间解的Ｓｔｕｒｍ比较定理，所得结论包含了一些经典的结论     

On congruences of Euler numbers modulo powers of two

In this paper, we establish some identities involving the Euler numbers, the Euler numbers of order 2 and the central factorial numbers, and give a new proof of a classical result due to M.A. Stern.

Video abstract

For a video summary of this paper, please visit http://www.youtube.com/watch?v=kdNsdTDA-FE.