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61.
Let t ≥ 2 be an integer, and let _(p_1, ···, p_t)be distinct primes. By using algebraic properties, the present paper gives a sufficient and necessary condition for the existence of non-trivial self-orthogonal cyclic codes over the ring Z_(p_1p_2···p_t)and the corresponding explicit enumerating formula. And it proves that there does not exist any self-dual cyclic code over Z_(p_1p_2···p_t). 相似文献
62.
Cui Yang Jinxue QiuChunyan Ren Xiangfan PiaoXifeng Li Xue WuDonghao Li 《Journal of chromatography. A》2009,1216(45):7694-7699
There is a trend towards the use of enrichment techniques such as microextraction in the analysis of trace chemicals. Based on the theory of ideal gases, theory of gas chromatography and the original headspace liquid phase microextraction (HS-LPME) technique, a simple gas flow headspace liquid phase microextraction (GF-HS-LPME) technique has been developed, where the extracting gas phase volume is increased using a gas flow. The system is an open system, where an inert gas containing the target compounds flows continuously through a special gas outlet channel (D = 1.8 mm), and the target compounds are trapped on a solvent microdrop (2.4 μL) hanging on the microsyringe tip, as a result, a high enrichment factor is obtained. The parameters affecting the enrichment factor, such as the gas flow rate, the position of the microdrop, the diameter of the gas outlet channel, the temperatures of the extracting solvent and of the sample, and the extraction time, were systematically optimized for four types of polycyclic aromatic hydrocarbons. The results were compared with results obtained from HS-LPME. Under the optimized conditions (where the extraction time and the volume of the extracting sample vial were fixed at 20 min and 10 mL, respectively), detection limits (S/N = 3) were approximately a factor of 4 lower than those for the original HS-LPME technique. The method was validated by comparison of the GF-HS-LPME and HS-LPME techniques using data for PAHs from environmental sediment samples. 相似文献
63.
Christophe Lacave 《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2009,26(4):1121-1148
In this work we study the asymptotic behavior of solutions of the incompressible two dimensional Euler equations in the exterior of a single smooth obstacle when the obstacle becomes very thin tending to a curve. We extend results by Iftimie, Lopes Filho and Nussenzveig Lopes, obtained in the context of an obstacle tending to a point, see [D. Iftimie, M.C. Lopes Filho, H.J. Nussenzveig Lopes, Two dimensional incompressible ideal flow around a small obstacle, Comm. Partial Differential Equations 28 (1–2) (2003) 349–379]. 相似文献
64.
65.
Erzsébet Néher-Neumann 《Journal of solution chemistry》2006,35(8):1085-1107
Equations are derived for the calculation of the total potential anomalies in Emf cells with liquid junctions (ΔE
J
) in mV and at 25.0 °C, defined as
wherez
j
= the charge number of the potential determining ion, J, and TS2 = terminal solution 2 ≡ test solution. This definition includes the activity factor (f
J
) contributions to the measuring electrode, the ideal diffusion potential (E
D
) and the contribution of the activity factors to E
D
, denoted by E
Df
. The cell assumed to contain an equilibrium solution which exists in the system, HY – BY
z(B)–A
y
L in the ionic medium (A+, Y−) with the experimental condition I (ionic strength) = CM, constant, in the mixed solutions. Here, L
y
− denotes the ligand and B
z
(B)+ the metal ions.The reasons for the dependence of the equilibrium constants on the ionic medium are given. The change of the equilibrium constants with the experimental conditions in a given ionic medium is also explained. 相似文献
66.
Qun Wei Chenyang Zhao Meiguang Zhang Haiyan Yan Yingjiao Zhou Ronghui Yao 《Physics letters. A》2018,382(25):1685-1689
A new superhard carbon orthorhombic allotrope oC20 is proposed, which exhibits distinct topologies including C4, C3 and two types of C6 carbon rings. The calculated elastic constants and phonon spectra reveal that oC20 is mechanically and dynamically stable at ambient pressure. The calculated electronic band structure of oC20 shows that it is an indirect band gap semiconductor with a band gap of 4.46 eV. The Vickers hardness of oC20 is 75 GPa. The calculated tensile and shear strength indicate that the weakest tensile strength is 64 GPa and the weakest shear strength is 48 GPa, which means oC20 is a potential superhard material. 相似文献
67.
模糊(左,右)理想格的结构 总被引:1,自引:0,他引:1
本文利用截集和集合套理论研究模糊(左,右)理想格的结构。证明了环R的模糊(左,右)理想格是模格,并给出了这类格中并HVK的构造。 相似文献
68.
L—Fuzzy拓扑空间的Os—连通性 总被引:8,自引:1,他引:7
在L-fuzzy拓扑空间中借助开集提出了一种具有fuzzy特色的Os-连通性,当s=0时,它就是O-连通性,讨论它的若干性质,证明它是L-好的推广。 相似文献
69.
偏序集上的滤子极大理想 总被引:3,自引:1,他引:2
在偏序集上引入并考察了滤子极大理想的概念,证明了相应的存在性定理。引入并考察了伪极大元和伪既约元的概念,利用图表的形式对连续格中各种类型的既约元和素元之间的关系进行了归纳总结,完善了文献《Continuous Lattices and Domains》(作者:G.Gierz,et al)中的一个图表的相关内容,填补了在分配的连续格情形该图表的一个未知内容,部分地回答了该文献中的一个问题。 相似文献
70.
关于BL-代数的模糊滤子与模糊理想 总被引:3,自引:1,他引:2
在BL-代数中引入模糊超滤子和模糊固执滤子的概念,证明了如下条件对于BL-代数的非常数模糊滤子f来说是等价的:(1)f是布尔的和素的,(2)f是蕴涵的和素的,(3)f是超的,(4)f是固执的。应用模糊正蕴涵滤子给出G-代数的若干特征性质。提出BL-代数模糊理想的概念,给出一些重要例子,并通过例子说明在BL-代数中模糊理想一般不能由模糊滤子导出。同时,从模糊理想出发构造了商BL-代数,并建立了相应的同态基本定理。最后,研究了BL-代数的几类模糊理想及其相互关系,给出模糊布尔理想、模糊素理想、模糊超理想的特征性质。 相似文献