Enhanced energy storage properties in PbZrO3 thin films via the incorporation of NiO

Wang X.W.,Chen J.Y.,Hu S.Y.,Yu K.X.,Yang F.,Shi Y.J.,Li J.H.,Hou M.Z.,Liu A.D.,Zheng M.M.,Yin S.Q.,Hu Y.C.,Shang J. 한국물리학회 2023 Current Applied Physics Vol.52 No.-

In this study, NiO–PbZrO3 composite films were deposited on SiO2/Si substrates buffered with LaNiO3 films via the sol-gel coating technique. The effects of NiO addition in PZO thin films on the microstructure, dielectric properties, leakage mechanism, ferroelectric properties and energy storage properties have been discussed. The dielectric constant increased with the addition of NiO, while the leakage current density decreased. Compared with pure PZO films, the maximum polarization of the composite films was improved. For the composite films prepared using the NiO precursor solution with 0.05 mol/L, the recoverable energy storage density of the NiO-PZO composite film is up to 19.6 J/cm3 under the electric field of 1038 kV/cm, which is 30% higher than that of the pure PZO film under the same conditions. Also, the energy storage efficiency of the composite film reaches 48%. Accordingly, we demonstrate a simple and convenient method by adding NiO to fabricate thin films with high energy storage performance.

Dual NURBS Path Smoothing for 5-Axis Linear Path of Flank Milling

Dongdong Li,Weimin Zhang,Wei Zhou,Tengfei Shang,Jürgen Fleischer 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.12

Linear path is still widely used to describe the five-axis machining trajectory. Five-axis tool path consists of two parts, one trajectory describes the tool tip position, and the other one represents the second point on tool axis to define the tool orientation. The natural disadvantages of G01 path are tangential and curvature discontinuities at freeform surface, which will lead to feedrate fluctuation and accuracy decrease due to the drive constraints of machine tool. In this study, a path smoothing method is proposed to smooth and optimize the linear path by using dual NURBS curves. Firstly, according to the accuracy requirements, the tool tip spline can be fitted. Secondly, the tool orientation spline can also be obtained by a coordinate system mapping method. Then, the synchronization equation of the two spline parameters is established to achieve interpolation synchronization of cutter location points. Finally, the smoothing dual NURBS tool path can be obtained with continuous curvature to improve the surface quality, motion stability and machining efficiency. Simulations and experiments validate its practicability and reliability. This method is no need to upgrade the CAM, and also could be integrated into CAM system to perform the 5-axis path smoothing.

Consolidation of marine clay using electrical vertical drains

Shang, J.Q.,Tang, Q.H.,Xu, Y.Q. Techno-Press 2009 Geomechanics & engineering Vol.1 No.4

Electroosmosis (EO) is the movement of water in a porous medium under the influence of a direct current (dc). In past decades, electro-osmosis has been successfully employed in many soil improvement and other geotechnical engineering projects. Metal electrodes, such as steel, copper and aluminum have been used traditionally to conduct current. The shortcoming of these electrodes is that they corrode easily during an EO treatment, which results in reduced effectiveness and environmental concerns. More recently, conductive polymers are developed to replace metal electrodes in EO treatment. Electrical vertical drainages (EVDs) are one of these products under trial. The goal of this study is to assess the performance of EVDs for soil improvement and to further understand the scientific principle of the EO process, including the voltage drop at the soil-EVD interface, electrical current density, polarity reversal, and changes in soil physico-chemical properties generated by electroosmosis. It is found from the study that after 19 days of EO treatment with a constant applied dc electric field intensity of 133 V/m, the soil's moisture content decreased by 28%, the shear strength and pre-consolidation pressure increased more than 400%. It is also found that the current density required triggering the water flow in the soil tested, the Korean Yulchon marine clay, is 0.7 $A/m^2$. The project demonstrates that EVDs can serve as both electrodes and drains for soil improvement in short term. However, the EVDs, as tested, are not suitable for polarity reversal in EO treatment and their service life is limited to only 15 days.

Influencing factors on electrical conductivity of compacted kaolin clay

Lee, J.K.,Shang, J.Q. Techno-Press 2011 Geomechanics & engineering Vol.3 No.2

The electrical conductivity of a soil-water system is related to its engineering properties. By measuring the soil electrical conductivity, one may obtain quantitative, semi-quantitative, or qualitative information to estimate the in-situ soil behavior for site characterization. This paper presents the results of electrical conductivity measured on compacted kaolin clay samples using a circular two-electrode cell in conjunction with a specially designed compaction apparatus, which has the advantage of reducing errors due to sample handling and increasing measurement accuracy. The experimental results are analyzed to observe the effects of various parameters on soil electrical conductivity, i.e. porosity, unit weight, water content and pore water salinity. The performance of existing analytical models for predicting the electrical conductivity of saturated and unsaturated soils is evaluated by calculating empirical constants in these models. It is found that the Rhoades model gives the best fit for the kaolin clay investigated. Two general relationships between the formation factor and soil porosity are established based on the experimental data reported in the literature and measured from this study for saturated soils, which may provide insight for understanding electrical conduction characteristics of soils over a wide range of porosity.

In-situ study of beneficial utilization of coal fly ash in reactive mine tailings

Lee, J.K.,Shang, J.Q.,Wang, H.,Zhao, C. Academic Press 2014 Journal of environmental management Vol.135 No.-

Oxidation of reactive mine tailings and subsequent generation of acid mine drainage (AMD) have been long recognized as the largest environmental concern for the mining industry. Laboratory studies on utilization of coal fly ash in management of reactive mine tailings have shown reducing water and oxygen infiltration into tailings matrix, thus preventing oxidation of sulphide minerals and acid generation. However, few data from field studies to evaluate the performance of co-placement of mine tailings and fly ash (CMF hereafter) are reported in the open literature. This paper documents the construction and instrumentation of three CMF systems on the Musselwhite mine located in Ontario, Canada and presents results of 3-year real time monitoring. The field data indicates that the CMFs reduced the ingress of water due to cementation generated by hydration of fly ash. It was also found that the electrical conductivity of leachate from CMFs decreased in the early stage of co-placement, compared to the control. With further study, the principle and approach demonstrated in this paper can be adopted as a sustainable technology in the mine tailings management.

Undrained bearing capacity of ring foundations on two-layered clays

Lee, J.K.,Jeong, S.,Shang, J.Q. Pergamon Press 2016 Ocean engineering Vol.119 No.-

This paper presents the results of a numerical investigation into the undrained vertical bearing capacity of rough ring foundations resting on two-layered clays of both homogeneous and linearly increasing shear strength profiles. Small displacement finite element predictions are compared with the available empirical, analytical and numerical solutions, and expressed in the familiar form of bearing capacity factors reflecting the coupling effects of the dimensionless parameters related to foundation internal opening, relative top layer thickness, strength difference between two layers, and strength non-homogeneity. The depth beyond which the shear strength of the bottom layer does not affect the bearing capacity, defined here as critical depth ratio, is identified. The failure mechanisms of ring foundations are also discussed in terms of the displacement pattern.

구조동역학에서 iIRS방법을 활용한 효율적인 머신러닝 접근 방안

이재혁(J. H. Lee),이재철(J. C. Lee),샹위웨이(Y. W. Shang),리숴(S. Li),김성은(S. E. Kim),안준걸(J. G. Ahn),양현익(H. I. Yang) 한국생산제조학회 2021 한국생산제조시스템학회 학술발표대회 논문집 Vol.2021 No.12

Thermo-mechanical properties and microfabric of fly ash-stabilized gold tailings

Lee, J.K.,Shang, J.Q.,Jeong, S. Elsevier Scientific Pub. Co 2014 Journal of hazardous materials Vol.276 No.-

This paper studies the changes in thermal conductivity, temperature, and unconfined compressive strength of gold tailings and fly ash mixtures during the curing period of 5 days. The microfabric of the cured mixtures was investigated with mercury intrusion porosimetry (MIP). The mixture samples were prepared at their maximum dry unit weight and optimum moisture content. Effect of adding fly ash to gold tailings (i.e., 0, 20, and 40% of the dry weight of tailings) was examined, and a comparison was made on samples prepared at the same fly ash content by replacing gold tailings with humic acid (i.e., gold tailings and humic acid ratios of 100:0, 90:10, and 80:20 by weight) or by varying pore fluid chemistry (i.e., water and salt solutions of 1M NaCl and CaCl<SUB>2</SUB>). The results show that the initial thermal conductivity of the samples is sensitive to the mixture proportion and a declination in the thermal conductivity is observed due to hydration of fly ash and evaporation. Inclusion of fly ash and salts into gold tailings improves the unconfined compressive strength but the presence of humic acid in samples leads to the decrease of the strength. MIP results reveal the pore structure changes associated with the packing states of the samples that reflect the influential factors considered.

Laser Raman detection of platelet as a non‐invasive approach for early and differential diagnosis of Alzheimer's disease

Chen, P.,Tian, Q.,Baek, S.J.,Shang, X.L.,Park, A.,Liu, Z.C.,Yao, X.Q.,Wang, J.Z.,Wang, X.H.,Cheng, Y.,Peng, J.,Shen, A.G.,Hu, J.M. WILEY‐VCH Verlag 2011 Laser physics letters Vol.8 No.7

<P><B>Abstract</B></P><P>Early and differential diagnosis of Alzheimer's disease (AD) is a problem that puzzled many doctors. Reliable markers in easy‐assembling samples are of considerable clinical diagnostic value. In this work, laser Raman spectroscopy (LRS) was developed a new method that potentially allows early and differential diagnosis of AD from the platelet sample. Raman spectra of platelets isolated from different ages of AD transgenic mice and non‐transgenic controls were collected and analyzed. Multilayer perceptron networks (MLP) classification method was used to classify spectra and establish the diagnostic models. For differential diagnosis, spectra of platelets isolated from AD, Parkinson’s disease (PD) and vascular dementia (VD) mice were also discriminated. Two notable spectral differences at 740 and 1654 cm<SUP>–1</SUP> were revealed in the mean spectrum of platelets isolated from AD transgenic mice and the controls. MLP displayed a powerful ability in the classifying of early, advanced AD and the control group, and in differential diagnosis of PD and advanced AD, as well as VD and advanced AD. The results suggest that platelet detecting by LRS coupled with MLP analysis appears to be an easy and accurate method for early and differential diagnosis of AD. This technique could be rapidly promoted from laboratory to the hospital. (© 2011 by Astro Ltd., Published exclusively by WILEY‐VCH Verlag GmbH & Co. KGaA) (© 2011 by Astro Ltd., Published exclusively by WILEY‐VCH Verlag GmbH & Co. KGaA)</P>

Understanding Mobile TV Streaming Service Users’ Perception through Cognitive Mapping Method

J.B (Joo Baek) Kim,Soo Il Shin,Yanyan Shang 한국경영정보학회 2021 한국경영정보학회 학술대회논문집 Vol.2021 No.11

Recently many content consumers watch professionally produced video/TV content over mobile-based streaming services using the Over-the-Top (OTT) platforms. The current study is aimed to understand the users’ perception of mobile TV streaming services through the lens of the sociocognitive method. Using cognitive mapping stemmed from social representation theory, our study explores the core and peripheral user perceptions toward mobile TV streaming services. We collected words or short phrases that best describe the mobile TV streaming services from 432 users. Then, the data were coded and analyzed to create a cognitive map through the similarities calculation and identifying the core/peripheral perceptions. Finally, we interpret the structure of the cognitive map that reflects the mobile TV users’ perceptions. The findings of this study reveals certain aspects of the mobile TV streaming services are more or less appreciated through which we provide a strategic guide to the industry.