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111.
Polyethers, which are produced by alcoholysis of oxiranes, are often used as solvents in chemical plants. The spectra of the products can be influenced by the choice of the catalyst (acid or base). The results of the base-catalyzed ethanolysis of 1,2-epoxybutane are displayed. The reaction was investigated calorimetrically by varying the molar ratio between ethanol and 1,2-epoxybutane, the starting temperature and the concentration of the catalyst sodium hydroxide. Additionally, the influence of the used alcohol will be shown in one example. To determine the activation parameters, the experiments were evaluated by the nonlinear software package TA-kin v3.3. 相似文献
112.
本文对某些非线性方程组F(x)=0,导出了一个算法,用它可以迭代建立F(x)=0的解的紧致上、下界。算法基于某些矩阵的多分裂,因此具有自然的并行性。我们证明了趋向于解的界之收敛原则,给出了参数的收敛性区域并考察了方法的收敛速度。 相似文献
113.
Hiroshi Konno 《Mathematical Programming》1988,41(1-3):185-193
We will consider a concave minimization problem associated with a series production system in which raw material is processed inm consecutive facilities. The products at some facility are either sent to the next facility or stocked in the warehouse. The amount of demand for the final products during periodi, i = 1,,n, are known in advance. Our problem is to minimize the sum of processing, holding and backlogging cost, all of which are assumed to be concave.The origin of this model is the classical economic lot size problem of Wagner and Whitin and was extensively studied by Zangwill. This model is very important from the theoretical as well as practical point of view and this is one of the very rare instances in which polynomial time algorithm has been constructed for concave minimization problems.The purpose of this paper is to extend the model further to the situation in which time lag is associated with processing at each facility. We will propose an efficient O(n
4
m) algorithm for this class of problems. 相似文献
114.
The reaction of W(CO)6 with pyOSNa (C5-H4NOSNa) and Et4NCl in MeCN affords a new tungsten(0) complex [Et4N][W(pyS)(CO)4] 1 (Mr.= 536.29).The crystal and molecular structures have been determined by X-ray single-crystal diffraction.Complex 1 crystallizes in the orthorhombic system,space group P212121 with a = 8.2429(5),b = 9.1045(4),c =26.8851(14) (A),β = 90.00°,V= 2017.66(18) (A)3,Z = 4,Dc.= 1.765 g/cm3,μ = 58.51 cm-1,F(000) =1048,the final R = 0.0204 and wR = 0.0400 for 4432 observed reflections with I > 2σ(I).X-ray structure analysis revealed that the molecule is acentric and has large first-order hyperpolarizability (7.2 × 10-30 esu),so it could be an IR second-order nonlinear optical candidate material. 相似文献
115.
B. T. Sutcliffe 《Theoretical chemistry accounts》1974,33(3):201-214
It is shown that in the LCAO-MO-SCF problem, if the molecular orbital orthonormality constraints are introduced in the manner first suggested by Fletcher, then the Hessian of the problem is singular. It is suggested that this singularity may well account for the slow convergence observed using direct energy minimization methods to solve the SCF problem. Ways of avoiding the consequences of this singularity are discussed. 相似文献
116.
大肠杆菌有限生长的微量热及非线性动力学研究 总被引:2,自引:0,他引:2
The finite growth of Escherichia coli was studied by using a LKB 2277 BioActivity Mollitor. We found that the finite growth is a nonliear dynamic process. The nonlinear dynamic behaviour in the finite growth process and the nonlinear dynamic models describing the process were discovered and established. The curve of logistic map corresponding to the finite growth thermogram of Escherichia coli was obtained and the nonlinear dynamic parameters were calculated by means of a computer. Moreover, we also discussed the nonlinear dynamic characters of Escherichia colt in its finite growth process. 相似文献
117.
Convex programs with an additional reverse convex constraint 总被引:2,自引:0,他引:2
H. Tuy 《Journal of Optimization Theory and Applications》1987,52(3):463-486
A method is presented for solving a class of global optimization problems of the form (P): minimizef(x), subject toxD,g(x)0, whereD is a closed convex subset ofR
n
andf,g are convex finite functionsR
n
. Under suitable stability hypotheses, it is shown that a feasible point
is optimal if and only if 0=max{g(x):xD,f(x)f(
)}. On the basis of this optimality criterion, the problem is reduced to a sequence of subproblemsQ
k
,k=1, 2, ..., each of which consists in maximizing the convex functiong(x) over some polyhedronS
k
. The method is similar to the outer approximation method for maximizing a convex function over a compact convex set. 相似文献
118.
Solid-state nanopore in analytical chemistry has developed rapidly in the 1990s and it is proved to be a versatile new tool for bioanalytical chemistry. This review focuses on the analysis of ions and small molecules with nanopores including nanopipettes, polymer film nanopores, Si3N4 nanopores, graphene nanopores, MoS2 nanopores and MOFs. 相似文献
119.
Low molecular weight tri-podal biphenyl- and benzoate-type mesogens [C6H5C6H4O(CH2)5SiMe2CH2CH2SiMe2]3CH (4), [C11H23O(C6H4)2O(CH2)5SiMe2]3CH (5) and [MeOC6H4OC(O)C6H4O(CH2)5SiMe2]3CH (6) (C6H4 = 1,4-phenylene) were obtained, from branched silyl substituted methane precursors [CH2CH(Me)2Si]3CH (1) and (HMe2Si)3CH (2). The biphenyl-containing ones (4) and (5) were converted into terminal alkenes, which were subsequently hydrosilylated with poly(methylsiloxanes). The polymer derived from (5) exhibited mesomorphic properties. Such systems have the potential to significantly increase the density of liquid crystal rod-like structures in side chains of linear polymers (or dendritic liquid crystal polymers). 相似文献
120.
本文用数学期望方法研究了非线型共缩聚物的重均分子量,并推导出重均分子量表达式,将3种特例的理论曲线与实验结果相比较,两者基本相符。 相似文献