Effect of Nitrogen Donor Disposition on Topology in Cobalt Isophthalate Coordination Polymers Containing Dipyridylamide Ligands

Cobalt coordination complexes containing a substituted isophthalate ligand and hydrogen‐bonding capable dipyridylamide ligands were prepared hydrothermally and structurally characterized by single‐crystal X‐ray diffraction. {[Co(nip)(3‐pina)]_n ( 1 ) (nip = 5‐nitroisophthalate, 3‐pina = 3‐pyridylisonicotinamide) displays [Co(nip)]_n 1D ribbon motifs with embedded {Co₂(OCO)₂} dimeric units, linked by L‐shaped 3‐pina tethers into a 3D [Co(nip)(3‐pina)]_n coordination polymer network with pcu topology. In contrast, {[Co(nip)(4‐pmina)(H₂O)] · H₂O}_n ( 2 ) (4‐pmina = 4‐pyridylmethylisonicotinamide) manifests a twofold interpenetrated 6⁶ topology diamondoid network. {[Co(meoip)(3‐pina)]_n ( 3 ) (meoip = 5‐methoxyisophthalate) has a dimer‐based 3D pcu network as seen in 1 . [Co(meoipH)₂(4‐pmina)₂(H₂O)₂] ( 4 ) contains neutral coordination complexes linked by hydrogen‐bonding into supramolecular ribbons. Thermal properties of these new solids were also investigated.     

On Some L-extensions of Dimensions of Topological Spaces

The concepts of covering dimension,small inductive dimension and large inductive dimension for topological spaces are extended to L-topological spaces using the quasi-coincidence relation.Besides getting some characterizations,it is also seen that all these characterizations are good in the sense of Lowen.     

模糊粗糙近似算子的拓扑性质

考虑论域上一二元关系所决定的模糊粗糙近似算子的拓扑性质,证明了任一自反二元关系可以决定一模糊拓扑.并且,当二元关系自反对称时,该模糊拓扑中的元是开集当且仅当它是闭集;当二元关系自反传递时,该模糊拓扑的闭包与内部算子恰为模糊粗糙上、下近似算子.     

A hidden Markov model with molecular mechanics energy-scoring function for transmembrane helix prediction

A range of methods has been developed to predict transmembrane helices and their topologies. Although most of these algorithms give good predictions, no single method consistently outperforms the others. However, combining different algorithms is one approach that can potentially improve the accuracy of the prediction. We developed a new method that initially uses a hidden Markov model to predict alternative models for membrane spanning helices in proteins. The algorithm subsequently identifies the best among models by ranking them using a novel scoring function based on the folding energy of transmembrane helical fragments. This folding of helical fragments and the incorporation into membrane is modeled using CHARMm, extended with the Generalized Born surface area solvent model (GBSA/IM) with implicit membrane. The combined method reported here, TMHGB significantly increases the accuracy of the original hidden Markov model-based algorithm.     

Analysis of entry flow to determine elongation flow properties revisited

The minimisation technique proposed by Binding (J. Non-Newtonian Fluid Mech., 27 (1988) 173) was used in our Generalised Engineering Bernoulli Equation framework to relate the entry pressure and stress power. We arrived at a final result similar to Binding's using assumed kinematics. Through subsequent assumptions to the kinematics we finally arrive at a result exactly equivalent to Cogswell's technique (Trans. Soc. Rheol., 16 (1972) 383). Thus, these two techniques are related in this general framework. The techniques were used to predict elongation flow properties of a polymer melt and polymer solution. The results for the polymer melt clearly show Cogswell's technique is adequate at high elongation rates. All these techniques require minimisation of the stress power with respect to the flow volume and discussion is given as to the validity of this minimisation technique. In addition, the approximate variational technique we propose gives clears limits as to when a technique, such as Cogswell's, can be applied.     

Detecting extensional viscosity of polypropylene melt using the Rheotens test: A comparison between standard and steady state test modes

The Rheotens test was used to determine the extensional viscosity of a polypropylene (PP) melt at three different extrusion velocities and using two capillaries with different length-to-diameter ratios. Results showed that, in the standard Rheotens test, the extensional viscosity curves determined under different testing conditions exhibit an obvious difference, especially under low extensional strain rates. This is attributed to the pre-orientation of macromolecular chains taking place in the capillary. Hence, a steady state Rheotens test was tentatively proposed. It was demonstrated that the extensional viscosity curves determined under most of the testing conditions by this test mode almost overlap, which is attributed to the fact that the pre-orientation of chains relaxes sufficiently near the capillary exit. This implies that equivalent extensional viscosities can be obtained under a wider range of extrusion velocities and capillary length-to-diameter ratios. Moreover, the equivalent extensional viscosities determined in the steady state Rheotens test exhibit good agreement with the extrapolated extensional viscosity curve determined using the Cogswell convergent flow method.     

具有缺项系数的几类解析函数族的性质

S*表示所有在单位圆盘 D 内解析且满足条件 f(0)=f′ (0)-1=0的星形函数族, K 表示所有在 D内解析且满足条件 f(0)=f′ (0)-1=0 的凸函数族, P 表示所有在 D 内解析且满足条件p(0)=1, Rep(z)>0 的函数族. 设P_n={p(z): p(z)=1+a_nzⁿ+a_n+1zⁿ⁺¹+…∈ P}, S*_n={f (z): f(z)=z+a_nzⁿ+a_n+1zⁿ⁺¹+…∈ S*}, K_n={f (z): f (z)=z+a_nzⁿ+a_n+1zⁿ⁺¹+…∈ K}. L_Sn*={g(z)=ln f(z)/z, f ∈ S_n*}, 其中对数函数取使得ln1=0的那个单值解析分支. 该文研究了函数族S_n^*, K_n和L_Sn*的性质, 找出了解析函数族L_Sn*的极值点与支撑点,并对S*_n与K_n的极值点和支撑点作了一些探讨.     

L-Fuzzy拓扑空间中的杨忠道定理

本文将分明拓扑学中的杨忠道定理推广到LF拓扑学中,而对Fuzzy格L不再附加 任何条件.     

完全分配格上的格值Smooth点式拟一致结构

在完全分配格上定义L—smooth点式拟一致结构概念，并研究它与点式拟一致结构之间的关系以及与smooth拓扑之间的关系，给出分解定理、表现定理及构造条件。