双(二吡啶胺)配体的二维和三维超分子配位聚合物的合成与晶体结构

从含4,4'-二吡啶胺结构单元的双(二吡啶胺) 桥联配体出发,采用溶剂热法合成了两个结构新颖的配位聚合物：[CdL1Br2]n?7.5nH2O (L1 = N,N,N′,N′-四(4-吡啶)-1,4-苯二胺) (1)和[Cu2L2(μ1,1,3-SCN)2]n?nMeOH (L2 = N,N-二(2-吡啶)-N',N'-二(4-吡啶)-1,4-苯二胺) (2),对它们进行了元素分析、红外光谱等表征,并用X-射线单晶衍射测定了其晶体结构。单晶测试结果显示,配合物1中配体L1的四个吡啶N原子均参与配位,桥联了4个Cd原子,每个Cd原子与四个吡啶 N 原子和两个溴配位,形成六配位的八面体构型。通过这些配位作用,最终形成包含 Kagome 结构的三维超分子网络。配合物2 是由一维柱状 {Cu(SCN)}n 链通过 L2 桥联生成的二维结构。有趣的是,L2中具有螯合能力的2,2'-二吡啶胺单元并未参与配位,只有4,4'-二吡啶胺单元中的两个吡啶N原子分别与一个 Cu(I) 配位,连接了相邻两条平行的{Cu(SCN)}n 链,生成二维结构。     

带有阈值转换和启动时间的优先权排队

在诸如ＩＳＤＮ的通信网络中,多种信息共用一条线路,为了满足不同类型信息的服务质量要求,带有阈值转换的优先权排队系统应是一种合适的模型。本文研究单服务员、两类顾客的带有阈值转换和启动时间的优先权排队系统,首先,分别就抢占和非抢占情形讨论了具有泊松到达、服务时间和启动时间均有指数贩系统,然后就非抢占情况进上步考虑了服务时间和启动时间有一般分布的系统,求出了系统中两类顾客队长的稳态联合概率母函数,藉助这     

Non-asymptotic Error Bound for Optimal Prediction of Function-on-Function Regression by RKHS Approach

In this paper,we study and analyze the regularized least squares for function-on-function regression model.In our model,both the predictors(input data)and respo...     

Spectroturbidimetry of polydisperse systems with spectral dispersion of optical constants taken into account

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 56, No. 3, pp. 435–440, March, 1992.     

Normal Families of Zero-free Meromorphic Functions Ⅱ

Let k, m be two positive integers with m ≤ k and let F be a family of zero-free meromorphic functions in a domain D, let h(z) ≡ 0 be a meromorphic function in D with all poles of h has multiplicity at most m. If, for each f ∈ F, f(k)(z) = h(z) has at most k- m distinct roots(ignoring multiplicity) in D, then F is normal in D. This extends the results due to Chang[1], Gu[3], Yang[11]and Deng[1]etc.     

‘Whole-molecule Disorder’ Refinement of 4-Tricyanovinyl-N,N-diethylaniline

The molecule of 4-tricyanovinyl-N,N-diethylaniline is disordered about an axis that is close to the axis passing through the 1,4-carbon atoms. The disorder is a 1:1 type of disorder that involves only part of the molecule as the diethylamino substitutent and the three nitrogen atoms of the tricyanovinyl substituent are ordered. The treatment of the nearly ‘whole-molecule disorder’ by employing a small number of restraints is described. Crystal data: C15H14N4, triclinic, P , a = 7.1996(5), b = 7.7232(5), c = 12.4171(8) , α = 99.350(1), β = 94.647(1), γ = 103.312(1)o and V = 657.90(8) 3 at –173 K.     

Effects of shape and charge of colloidal gold nanoparticles in colorimetric determination of DNA sequences

The principles of colorimetric detecting oligonucleotides with the help of gold nanospheres and nanorods are discussed. Marker sequences of fragments of HIV-1 genome and Bacillus anthracis are used as models. Experimental data are reported that demonstrate the influence of gold nanorod morphology on the reproducibility of colorimetric tests. A new method is proposed for detecting oligonucleotides based on the application of positively charged gold nanospheres in combination with absorption spectroscopy and dynamic light scattering. Charge reversal of negatively charged gold nanospheres is implemented through the bilayer adsorption of cetyltrimethylammonium bromide molecules. The sensitivity of the proposed method is comparable with the detection of DNA sequences via the colorimetric protocol using nanorods, but it is more simple and stable from the viewpoint of realization. It is shown that the colorimetric tests using gold nanorods and nanospheres do not provide reliable information on the presence of single- and three-base mismatches in target oligonucleotides.