Henan Normal University

About: Henan Normal University is a education organization based out in Xinxiang, China. It is known for research contribution in the topics: Catalysis & Ionic liquid. The organization has 10863 authors who have published 11077 publications receiving 166773 citations.

Apparent Molar Volumes and Viscosities of Some α-Amino Acids in Aqueous Sodium Butyrate Solutions at 298.15 K

Abstract: Densities and viscosities of aqueous solutions of α-amino acids (glycine, dl-alanine, dl-α-amino-n-butyric acid, dl-α-valine, and dl-α-leucine) + sodium butyrate have been measured as a function of concentrations of amino acid and electrolyte at 298.15 K. These data have been used to calculate apparent molar volumes and viscosity B-coefficients of the amino acids. The standard partial molar volumes, V°2,φ, standard volumes of transfer, ΔtV°, and hydration numbers of the amino acids have been determined. It has been shown that V°2,φ, ΔtV°, and the B-coefficient vary linearly with increasing number of carbon atoms in the alkyl chain of the amino acids, and they were split into contributions from the charged end group (NH3+, COO-) and CH2 groups of the amino acids. From the volumetric data, we found that sodium butyrate interacts strongly with the charged center of the zwitterion of the amino acids and has a strong dehydration effect on the amino acids.

h-index sequence and h-index matrix: Constructions and applications

Abstract: The calculation of Hirsch's h-index is a detail-ignoring way, therefore, single h-index could not reflect the difference of time spans for scientists to accumulate their papers and citations. In this study the h-index sequence and the h-index matrix are constructed, which complement the absent details of single h-index, reveal different increasing manner and the increasing mechanism of the h-index, and make the scientists at different scientific age comparable.

Asymmetric polyamide nanofilms with highly ordered nanovoids for water purification

Abstract: Tailor-made structure and morphology are critical to the highly permeable and selective polyamide membranes used for water purification. Here we report an asymmetric polyamide nanofilm having a two-layer structure, in which the lower is a spherical polyamide dendrimer porous layer, and the upper is a polyamide dense layer with highly ordered nanovoids structure. The dendrimer porous layer was covalently assembled in situ on the surface of the polysulfone (PSF) support by a diazotization-coupling reaction, and then the asymmetric polyamide nanofilm with highly ordered hollow nanostrips structure was formed by interfacial polymerization (IP) thereon. Tuning the number of the spherical dendrimer porous layers and IP time enabled control of the nanostrips morphology in the polyamide nanofilm. The asymmetric polyamide membrane exhibits a water flux of 3.7−4.3 times that of the traditional monolayer polyamide membrane, showing an improved divalent salt rejection rate (more than 99%), which thus surpasses the upper bound line of the permeability−selectivity performance of the existing various structural polyamide membranes. We estimate that this work might inspire the preparation of highly permeable and selective reverse osmosis (RO), organic solvent nanofiltration (OSNF) and pervaporation (PV) membranes. Structure and morphology are critical to the performance of permeable and selective polyamide membranes in water purification. Here, the authors report a two layer asymmetric polyamide nanofilm in which a spherical polyamide dendrimer porous lower and a polyamide dense upper layer form hierarchical nanovoids.