Spaces with σ-locally Countable Weak Bases

In this paper, by msss_mappings, the relations between metric spaces and spaces with σ _locally countable cs_networks or spaces with σ _locally countable weak bases are established. These are some answers to Alexandroff’s problems.

A Note on Weak Open cs-images of Metric Spaces

In this paper, we prove that a space with a compact Countable weak base if and only if it is a weak open cs-image of a metric space.

Weak base favoring the synthesis of highly ordered V-MCM-41 with well-dispersed vanadium and the catalytic performances on selective oxidation of benzyl alcohol

The key to improve the performance of heteroatom catalysts is to ensure the orderliness of catalysts and the good dispersion of heteroatoms.The alkalinity plays the indispensable role in synthetic process of V-MCM-41 catalyst.The excessive alkalinity of synthetic system will make the MCM-41 difficult to crystallize,even to dissolve.It is easy to accumulate for heteroatomic species in the system of low alkalinity.Herein,the highly ordered VMCM-41 with high vanadic content in framework is synthesized in the condition of excessive NH3·H2 O in this paper.A series of characterization results prove the good dispersion of vanadium species,and most of vanadium gets into the framework of MCM-41 with the states of tetravalence and pentavalence.Furthermore,the modified MCM-41 by other transition metals is successful synthesized by the method of V-MCM-41 in this paper.The VMCM-41 shows well catalytic activity for the selective oxidation of benzyl alcohol,which up to 74.83%for the conversion of benzyl alcohol and 96.20%for selectivity of benzaldehyde when initial V/Si=0.10.The paper provides the possibility for industrial application of V-MCM-41 in the oxidation of benzyl alcohol for benzaldehyde.Besides,the work provides a significant idea for the synthesis of modified MCM-41 by well-dispersed transition metals.

THERMODYNAMIC STUDY ON ADSORPTION OF AROMATIC SULFONIC ACIDS ONTO MACROPOROUS WEAK BASE ANION EXCHANGER FROM AQUEOUS SOLUTIONS

The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, p-toluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anion exchanger within the temperature range of 293 K-313 K were obtained. Several isotherm equations were correlated with the equilibrium data, and the experimental data was found to fit the three-parameter Redlich-Peterson equation best within the entire range of concentrations. The study showed that the hydrophobicity of solute has distinct influence on adsorption capacity of the anion exchanger for the aromatic sulfonic acid. Moreover, estimations of the isosteric enthalpy, free energy, and entropy change of adsorption were also reported. The positive isosteric enthalpy and entropy change for adsorption indicate an endothermic and entropy driven process in the present study.

Vibration diagnostics of weak base embankments

In this paper the theoretical background was analyzed for vibration diagnostics method and experience in its application for weak base embankments. General schemes of survey and recommendations on hardware systems and further prospective development are outlined.

A LEAST SQUARE BASED WEAK GALERKIN FINITE ELEMENT METHOD FOR SECOND ORDER ELLIPTIC EQUATIONS IN NON-DIVERGENCE FORM

This article is devoted to establishing a least square based weak Galerkin method for second order elliptic equations in non-divergence form using a discrete weak Hessian operator.Naturally,the resulting linear system is symmetric and positive definite,and thus the algorithm is easy to implement and analyze.Convergence analysis in the H2 equivalent norm is established on an arbitrary shape regular polygonal mesh.A superconvergence result is proved when the coefficient matrix is constant or piecewise constant.Numerical examples are performed which not only verify the theoretical results but also reveal some unexpected superconvergence phenomena.

QUANTITATIVE ANALYSIS OF VERY WEAK ACID AND BASE BY pH-FIXED TITRATION METHOD

pH-fixed titration method for the determination of weak acids and bases has been studied in this paper.It is not necessary to know the ionization constant of weak acid or base and the concentration of titrant. This method had been applied to determine phenol,4-aminoantipyrine and glycine,whose ionization constants range from 10^(-10)to 10^(-12).The results were satisfactory.

A Novel Method for the Synthesis of Mesoporous Molecular Sieve MCM-41

Using glycerol, glycol and water as solvent, cetyltrimethylammonium bromide (CTAB) as template, tetraethyl orthosilicate (TEOS) as silica source, ethylenediamine (EDA) as base source, mesoporous molecular sieve MCM-41 has been synthesized at room temperature, characterized by X-ray power diffraction and N2 adsorption. Compared with the samples synthesized by glycol and water, the samples synthesized by glycerol have larger pore diameter and high surface areas. Thus glycerol is an efficient solvent for preparing larger pore mesoporous MCM-41.

cs＊-regular Families and Metrization Theorems

In this paper, we proved that a sequential space has a cs＊-regular cs＊-network （or a cs＊-regular weak base） is metrizable, which generalized related results in [6], [12] and [14].

Adsorption and desorption properties for rhenium using a kind of weak-base anion resin

In this paper, a weak-base resin was adopted to recycle rhenium because of its excellent adsorption and desorption properties for rhenium, while the kinetics and thermodynamics properties of adsorbing rhenium from the rhenium stock solution were systematically investigated. The kinetics investigations confirm that the adsorption process of Re belongs to kinetic control by particle diffusion process and the corresponding reaction rate constant is 2.68 × 10-s s^-1. Then, the Langmuir and Freundlich models were used to describe the adsorption equilibrium behaviors of Re and the thermodynamics parameters are obtained. The results show that the Langmuir model is the best-fitted model, and the Gibbs free energy change of Re adsorption onto ZS 15 weak-base resin is AGO = - 10.59 ＋ 12.66T. To verify the weak-base resins for extracting rhenium in industrial application, the column experiments were operated in the spray solution generating by roasting the molybdenum concentrates. The results indicate that the weak-base resins possess excellent adsorptive selectivity for rhenium, and the ammonia solution with low concentration could sufficiently desorb rhe- nium from the resins.

Weak blind quantum signature protocol based on entanglement swapping

In this paper, we put forward a weak blind quantum signature scheme based on quantum entanglement swapping of Bell states. Different from the existing quantum signature schemes, our scheme can offer two-step verification security services to ensure the validity of the verification. In order to guarantee the unconditional security of the scheme, the quantum key distribution protocol and one-time pad encryption algorithm are employed in our scheme. Besides, the entanglement swapping of Bell states mechanism enhances the security of verification criteria. The proposed scheme has the properties of nonforgeability, nonrepudiation, lindness,and traceability.

measurement weak repeatability covariant condition wave-packet collapse

The conflict between the dynamics postulate（unitary evolution） and the measurement postulate（wavepacket collapse） of quantum mechanics has been reconciled by Zurek from an information transfer perspective [Phys.Rev. A 76（2007） 052110], and has further been extended to a more general scenario [Phys. Rev. A 87（2013） 052111].In this paper, we reconsider Zurek＇s new derivation by using weak repeatability postulate or covariant condition instead of repeatability postulate.

Efficiency of weak greedy algorithms for m-term approximations

We investigate the efficiency of weak greedy algorithms for m-term expansional approximation with respect to quasi-greedy bases in general Banach spaces.We estimate the corresponding Lebesgue constants for the weak thresholding greedy algorithm（WTGA） and weak Chebyshev thresholding greedy algorithm.Then we discuss the greedy approximation on some function classes.For some sparse classes induced by uniformly bounded quasi-greedy bases of L_p,12 the WCGA is better than the TGA.

Researches on point-discrete families

Based on the modern development of Metrization theorem for context,the main results obtained in recent ten years on point-discrete families are summarized.This paper mainly introduces the theory of the spaces with opoint-discrete bases,the spaces with certain o-point-discrete networks,and the relationship between the above spaces and the spaces with certain o-compactfinite networks.

K-Spaces Property of Product Spaces

Let K be a class of spaces which are eigher a pseudo-open s-image of a metric space or a k-space having a compact-countable closed k-network. Let K′ be a class of spaces which are either a Fréchet space with a point-countable k-network or a point-G_δ k-space having a compact-countable k-network. In this paper, we obtain some sufficient and necessary conditions that the products of finitely or countably many spaces in the class K or K′ are a k-space. The main results are that Theorem A If X, Y ∈ K. Then X x Y is a k-space if and only if (X, Y) has the Tanaka’s condition. Theorem B The following are equivalent: (a) BF(w2) is false. (b) For each X, Y ∈ K′, X x Y is a k-space if and only if (X, Y) has the Tanaka’s condition.