醋酸乙烯酯-马来酸酐共聚物与水解聚丙烯酰胺高分子络合物的研究

<正> 某些高分子在溶液中可以通过次价力形成高分子络合物.根据次价力的不同,可分为四类:聚电解质络合物、氢键络合物、立体络合物和电荷转移络合物.部分水解聚丙烯酰胺(简称HPAM)是在水悬浮体中被广泛使用的絮凝剂,醋酸乙烯酯-马来酸酐共聚物(简称VAMA)是一种能力很强的泥浆稀释剂.研究二者在水溶液中的相互作用,在理论上和应用上都有重要意义.我们曾研究了粘土对它们的吸附作用、改变泥浆流变性以     

The crystal structure of the molybdenum cementite Mo12Fe22C10 (ξ-phase)

The crystal structure of molybdenum cementite Mo₁₂Fe₂₂C₁₀ (-phase) has been determined by means of a single crystal x-ray diffraction study of crystal fragments. The lattice parameters were found to be:a=10.865 (3),b=7.767 (2),c=6.559 (2) Å and =120.13 (2)°, space group C2/m;Z=1. From the analysis ofPatterson maps and differenceFourier analysis the atomic parameters were derived, yielding a residual ofR=0.059. The crystal structure contains octahedral and triangular prismatic groups which accommodate the carbon atoms in their voids, as is usually found in interstitial compounds. The octahedral building group consists of four Mo- and two Fe-atoms, the triangular prism is built up by four Fe-and two Mo-atoms. The mode of filling of the metal polyhedra is discussed.

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Die Kristallstruktur von Molybdän-Zementit, Mo₁₂Fe₂₂C₁₀ (-Phase)

Zusammenfassung Die Kristallstruktur von Molybdän-Zementit, Mo₁₂Fe₂₂C₁₀ (-Phase) wird auf Grund von Einkristall-Beugungsaufnahmen unter Anwendung vonPatterson-and DifferentialFourier-Analysen bestimmt. In der monoklinen Elementarzelle (a=1.870;b=7.67;c=6.563 Å, =120.1°) Raumgruppe C 2/m befindet sich eine Formeleinheit Mo₁₂Fe₂₂C₁₀ (oderZ=2, Mo₆Fe₁₁C₅). DerR-Wert von 6% für 1200 Reflexe unterstreicht die Richtigkeit der Struktur, die aus oktaedrischen und trigonal prismatischen Gruppen aufgebaut ist. Die Oktaedergruppe besteht aus 4 Mo- und 2-Fe-Atomen, die trigonal prismatische Gruppe aus 4 Fe- und 2 Mo-Atomen. Die Kohlenstoffatome füllen die Lücken dieser Bauelemente, wie es für typische Einlagerungscarbide (Komplexcarbide) erwartet werden kann.

     

Vesicle formation in oleyldimethylamine oxide/sodium oleate mixtures

Vesicle formation in a mixture of oleyldimethylamine oxide (OleylDMAO) and sodium oleate (NaOl) was investigated by viscoelastic measurements and cryoscopic transmission electron micrograph (cryo-TEM) observations. The viscoelastic properties changed with increasing mole fraction of NaOl (X _NaOl) from the Maxwell behavior of OleylDMAO solutions (X _NaOl=0) suggesting a transient network of long flexible chains. For X _NaOl=0.2 and 0.4 mixtures, both the shear storage modulus G and the shear loss modulus G showed weak dependences on angular frequency with a relation G>G. From cryo-TEM observations, vesicles coexisted with threadlike micelles in mixtures of X _NaOl=0.2 and 0.3. As X _NaOl increased further (X _NaOl=0.5 and 0.6), threadlike micelles disappeared and the coexistence of vesicles and globular micelles was observed. At X _NaOl=0.5, the viscosity decreased remarkably, which was consistent with the disappearance of threadlike micelles. The results indicated that vesicles were formed by the addition of NaOl to OleylDMAO solutions, contrary to the expectation of a decrease of the packing parameter with the introduction of electric charges.     

Spectrophotometric study of complexation equilibria with H-point standard addition and H-point curve isolation methods

The use of H-point curve isolation (HPCIM) and H-point standard addition methods (HPSAM) for spectrophotometric studies of complex formation equilibria are proposed. One step complex formation, two successive stepwise and mononuclear complex formation systems, and competitive complexation systems are studied successfully by the proposed methods. HPCIM is used for extracting the spectrum of complex or sum of complex species and HPSAM is used for calculation of equilibrium concentrations of ligand for each sample. The outputs of these procedures are complete concentration profiles of equilibrium system, spectral profile of intermediate components, and good estimation of conditional formation constants. The reliability of the method is evaluated using model data. Spectrophotometric studies of murexide-calcium, dithizone-nickel, methyl thymol blue (MTB)-copper, and competition of murexide and sulfate ions for complexation with zinc, are used as experimental model systems with different complexation stoichiometries and spectral overlapping of involved components.     

活性炭自溶液吸附锌(II)离子及其配合物

近年来，有人提出通过表面处理提高活性炭表面电荷，加强对无机离子吸附力等观点，但活性炭对无机离子的吸附活性点，表面含氧基团及配体对吸附的影响等重要问题仍众说纷经[1－4]为此，本文提出用氧化一负离子化法处理活性炭，以表面酸度表征表面含氧基团的量，探讨活性炭对Zn（Ⅱ）及其配合物的吸附特性．1试验（1）试验材料活性发由北京光华木材厂出品，分析纯．过20－30目，BET法测得比表面为1316m2·g-1．在2．5×10－2mlo·dm－3的NaNO3中，测得等电点pHIEP为7．75[5]，元素含量（质量分数）为C（83．9％），N（0．07％），H（1…     

一类非线性复微分方程的超越亚纯解北大核心CSCD

本文主要研究非线性复微分方程f^(4)+a(z)ff^((k))=p_(1)(z)e^(α_(1)(z))+p_(2)(z)e^(α_(2)(z))的超越亚纯解,其中a,p_(1),p_(2)是非零的有理函数,α_(1),α_(2)是非常数的多项式.进一步地,考虑当亚纯解存在时,α_(1),α_(2),p_(1)和p_(2)所满足的条件.另外,还讨论了非线性复微分方程f^(3)+a(z)f’=p_(1)(z)e^(ν(z))+p_(2)(z)e^(-ν(z))的亚纯解的存在性,其中a,p_(1),p_(2)是非零的有理函数,ν是非常数的多项式.所得的结果直接推广了一些已知的结果.     

Tractability frontiers in probabilistic team semantics and existential second-order logic over the reals

Probabilistic team semantics is a framework for logical analysis of probabilistic dependencies. Our focus is on the axiomatizability, complexity, and expressivity of probabilistic inclusion logic and its extensions. We identify a natural fragment of existential second-order logic with additive real arithmetic that captures exactly the expressivity of probabilistic inclusion logic. We furthermore relate these formalisms to linear programming, and doing so obtain PTIME data complexity for the logics. Moreover, on finite structures, we show that the full existential second-order logic with additive real arithmetic can only express NP properties. Lastly, we present a sound and complete axiomatization for probabilistic inclusion logic at the atomic level.     

On intermediate inquisitive and dependence logics: An algebraic study

This article provides an algebraic study of intermediate inquisitive and dependence logics. While these logics are usually investigated using team semantics, here we introduce an alternative algebraic semantics and we prove it is complete for all intermediate inquisitive and dependence logics. To this end, we define inquisitive and dependence algebras and we investigate their model-theoretic properties. We then focus on finite, core-generated, well-connected inquisitive and dependence algebras: we show they witness the validity of formulas true in inquisitive algebras, and of formulas true in well-connected dependence algebras. Finally, we obtain representation theorems for finite, core-generated, well-connected, inquisitive and dependence algebras and we prove some results connecting team and algebraic semantics.     

Infinite lexicographic products

We generalize the lexicographic product of first-order structures by presenting a framework for constructions which, in a sense, mimic iterating the lexicographic product infinitely and not necessarily countably many times. We then define dense substructures in infinite products and show that any countable product of countable transitive homogeneous structures has a unique countable dense substructure, up to isomorphism. Furthermore, this dense substructure is transitive, homogeneous and elementarily embeds into the product. This result is then utilized to construct a rigid elementarily indivisible structure.     

The fluted fragment with transitive relations

The fluted fragment is a fragment of first-order logic (without equality) in which, roughly speaking, the order of quantification of variables coincides with the order in which those variables appear as arguments of predicates. It is known that this fragment has the finite model property. We consider extensions of the fluted fragment with various numbers of transitive relations, as well as the equality predicate. In the presence of one transitive relation (together with equality), the finite model property is lost; nevertheless, we show that the satisfiability and finite satisfiability problems for this extension remain decidable. We also show that the corresponding problems in the presence of two transitive relations (with equality) or three transitive relations (without equality) are undecidable, even for the two-variable sub-fragment.