Entity

Time filter

Source Type


Yongfeng L.,Ningxia Teachers University
Lecture Notes in Electrical Engineering | Year: 2013

pH is a widely-used concept and physical quantity in chemistry and related disciplines. However, many studies found that this concept has numerous shortcomings. For instance, in the theoretical world, no consistent definition has been given to it; its concepts are disorderly characterized without theoretical significance; its physical significance also is not undefined and has no universality; in the practical application, the concepts of pH reference, pH standard and pH scale all are highly unclear, and pH is impacted by the temperature, concentration and pressure of solutions as well. This paper proposes to use AG to measure the acidity or basicity of solutions and proves this method can overcome all the shortcomings of pH through theoretical derivation and experiment, further showing that using AG to measure the acidity or basicity of solutions is scientific in theories and feasible in practices, and also owns its advantages. © 2013 Springer-Verlag. Source


Zhao W.X.,Shaanxi Normal University | Zhao W.X.,Ningxia Teachers University | Wang Z.L.,Shaanxi Normal University
Transactions of the Institute of Metal Finishing | Year: 2013

The adhesion strength between acrylonitrile-butadiene-styrene (ABS) resin and electroless copper can be improved significantly by a low environmental pollution etching system containing H2SO4-MnO 2-Na4P2O7-H2O colloid as a replacement for conventional chromic acid etching solutions. In this paper, the effects of the H2SO4 concentration and Na 4P2O7 content on the surface topography, surface roughness and the adhesion strength were studied. When the H 2SO4 concentration was 12·9M, good etching performance was obtained. The average adhesion strength between the electroless copper and ABS substrate reached 1·30 kN m-1. The surface contact angle measurement indicated that the ABS surface became hydrophilic and the contact angle decreased from 92·1 to 31·2°. © 2013 Institute of Metal Finishing. Source


Zhao W.,Shaanxi Normal University | Zhao W.,Ningxia Teachers University | Wang Z.,Shaanxi Normal University
International Journal of Adhesion and Adhesives | Year: 2013

A low environmental pollution etching system, MnO2-H 2SO4-H3PO4-H2O colloid, was used to investigate surface etching performance of polycarbonate (PC) as a replacement for the chromic acid etching solution. The effects of H 2SO4 concentrations, H3PO4 concentrations and etching times upon the surface topography, surface chemistry and surface roughness were studied. With the appropriate etching treatment, the surface average roughness (Ra) of PC substrates increased from 3 to 177 nm, and the adhesion strength between the electroless copper and PC substrate also reached 1.10 KN m-1. After the etching treatment, the PC surface became hydrophilic and the surface contact angle decreased from 95.2° to 24.8°. The intensity of C-O groups increased and the new functional groups (-COOH) formed on the PC surface with the etching treatment, which improved the adhesion strength between PC substrate and elctroless copper film. © 2012 Elsevier Ltd. All rights reserved. Source


Liang Y.,Ningxia Teachers University
Engineering Technology, Engineering Education and Engineering Management - International Conference on Engineering Technology, Engineering Education and Engineering Management, ETEEEM 2014 | Year: 2015

With rutin standard sample as the comparison, flavonoid extraction rate as an indicator, UV-2450 ultraviolet visible light spectrophotometer to measure flavonoid content in planted Trollius chinensis through orthogonal experiment, this experiment optimizes process condition of flavonoid in Trollius chinensis through water extraction and ethanol extraction. The result shows that the flavonoid extraction rate of T rollius chinensis through ethanol extraction method is obviously higher than water extraction, and the optimal extraction process condition is: ethanol concentration is 75%, extraction time is 90 min, extraction times are 3, and fluid material ratio is 20:1. © 2015 Taylor & Francis Group, London. Source


Liang Y.,Ningxia Teachers University
Engineering Technology, Engineering Education and Engineering Management - International Conference on Engineering Technology, Engineering Education and Engineering Management, ETEEEM 2014 | Year: 2015

This article adopts the method of orthogonal experiment to study the process of total flavonoid in Trollius chinensis through ultrasonic wave-assisted extraction, microwave-assisted extraction and backflow extraction. Based on the simulation results, among these three methods of planted Trollius chinensis, in terms of flavonoid compound extraction efficiency, microwave extraction method is better than ultrasonic radiation extraction method, which is better than backflow extraction method. © 2015 Taylor & Francis Group, London. Source

Discover hidden collaborations