Kinetics of polyvinyl butyral hydrolysis in ethanol/water solutions

Wenwen Luan,Chunyu Wang,Zuoxiang Zeng,Weilan Xue,Xuelian He,Yu Bai 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.9

The hydrolysis kinetics of polyvinyl butyral (PVB) was studied in ethanol/water mixed solvents in the temperature range of 339.15-355.15 K, and a three-step hypothesis was proposed to describe the hydrolysis process. The influences of stirring speed, ethanol content and temperature on the hydrolysis of PVB were investigated, and an induction period (IP) phenomenon was found in the process of PVB hydrolysis. The ethanol content in the mixed solvents has a great influence on IP, which is due to the formation of the two kinds of water-ethanol clusters in the system. Temperature influences the IP by changing the catalytic activity of hydroxylamine hydrochloride (HH) on the hydrolysis of PVB. The shrinking core models with three controlling steps were used to fit the kinetic data, and the results indicate that the model controlled by chemical reaction is suitable to describe the kinetic behavior of PVB hydrolysis.

Design of a High-Voltage Piezoelectric Converter for Airbag Ignition Modules

Xiao, Hongbing,Du, Yu,Bai, Chunyu,Guo, Zerong,Yen, Kang K. The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.1

Due to the requirements for high reliability and accuracy, safety issues for airbag ignition systems need to be studied. In this paper, a high-voltage piezoelectric converter is designed to improve these requirements in airbag ignition systems. The proposed converter includes an inverter drive circuit, a Rosen piezoelectric transformer (PZT), an output circuit and a feedback control circuit. The key components of the high-voltage piezoelectric transformer are analyzed in detail. In addition, the proposed converter system is simulated and implemented for testing. The experimental results show that when the power supply is turned on, the charging time is less than 800ms. Furthermore, the output voltage of this converter can be kept between 2.9kV and 3.1kV, under high-efficiency constant current charging mode and zero-voltage switching conditions.

Design of a High-Voltage Piezoelectric Converter for Airbag Ignition Modules

Hongbing Xiao,Yu Du,Chunyu Bai,Zerong Guo,Kang K. Yen 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.1

Due to the requirements for high reliability and accuracy, safety issues for airbag ignition systems need to be studied. In this paper, a high-voltage piezoelectric converter is designed to improve these requirements in airbag ignition systems. The proposed converter includes an inverter drive circuit, a Rosen piezoelectric transformer (PZT), an output circuit and a feedback control circuit. The key components of the high-voltage piezoelectric transformer are analyzed in detail. In addition, the proposed converter system is simulated and implemented for testing. The experimental results show that when the power supply is turned on, the charging time is less than 800ms. Furthermore, the output voltage of this converter can be kept between 2.9kV and 3.1kV, under high-efficiency constant current charging mode and zero-voltage switching conditions.

Fast Intraframe Coding for High Efficiency Video Coding

( Han Huang ),( Yao Zhao ),( Chunyu Lin ),( Huihui Bai ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.3

The High Efficiency Video Coding (HEVC) is a new video coding standard that can provide much better compression efficiency than its predecessor H.264/AVC. However, it is computationally more intensive due to the use of flexible quadtree coding unit structure and more choices of prediction modes. In this paper, a fast intraframe coding scheme is proposed for HEVC. Firstly, a fast bottom-up pruning algorithm is designed to skip the mode decision process or reduce the candidate modes at larger block size coding unit. Then, a low complexity rough mode decision process is adopted to choose a small candidate set, followed by early DC and Planar mode decision and mode filtering to further reduce the number of candidate modes. The proposed method is evaluated by the HEVC reference software HM8.2. Averaging over 5 classes of HEVC test sequences, 41.39% encoding time saving is achieved with only 0.77% bitrate increase.

Auto-Covariance Analysis for Depth Map Coding

( Lei Liu ),( Yao Zhao ),( Chunyu Lin ),( Huihui Bai ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.9

Efficient depth map coding is very crucial to the multi-view plus depth (MVD) format of 3-D video representation, as the quality of the synthesized virtual views highly depends on the accuracy of the depth map. Depth map contains smooth area within an object but distinct boundary, and these boundary areas affect the visual quality of synthesized views significantly. In this paper, we characterize the depth map by an auto-covariance analysis to show the locally anisotropic features of depth map. According to the characterization analysis, we propose an efficient depth map coding scheme, in which the directional discrete cosine transforms (DDCT) is adopted to substitute the conventional 2-D DCT to preserve the boundary information and thereby increase the quality of synthesized view. Experimental results show that the proposed scheme achieves better performance than that of conventional DCT with respect to the bitrate savings and rendering quality.

Resolution-independent Up-sampling for Depth Map Using Fractal Transforms

( Meiqin Liu ),( Yao Zhao ),( Chunyu Lin ),( Huihui Bai ),( Chao Yao ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.6

Due to the limitation of the bandwidth resource and capture resolution of depth cameras, low resolution depth maps should be up-sampled to high resolution so that they can correspond to their texture images. In this paper, a novel depth map up-sampling algorithm is proposed by exploiting the fractal internal self-referential feature. Fractal parameters which are extracted from a depth map, describe the internal self-referential feature of the depth map, do not introduce inherent scale and just retain the relational information of the depth map, i.e., fractal transforms provide a resolution-independent description for depth maps and could up-sample depth maps to an arbitrary high resolution. Then, an enhancement method is also proposed to further improve the performance of the up-sampled depth map. The experimental results demonstrate that better quality of synthesized views is achieved both on objective and subjective performance. Most important of all, arbitrary resolution depth maps can be obtained with the aid of the proposed scheme.

Fast Algorithm for Intra Prediction of HEVC Using Adaptive Decision Trees

( Xing Zheng ),( Yao Zhao ),( Huihui Bai ),( Chunyu Lin ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.7

High Efficiency Video Coding (HEVC) Standard, as the latest coding standard, introduces satisfying compression structures with respect to its predecessor Advanced Video Coding (H.264/AVC). The new coding standard can offer improved encoding performance compared with H.264/AVC. However, it also leads to enormous computational complexity that makes it considerably difficult to be implemented in real time application. In this paper, based on machine learning, a fast partitioning method is proposed, which can search for the best splitting structures for Intra-Prediction. In view of the video texture characteristics, we choose the entropy of Gray-Scale Difference Statistics (GDS) and the minimum of Sum of Absolute Transformed Difference (SATD) as two important features, which can make a balance between the computation complexity and classification performance. According to the selected features, adaptive decision trees can be built for the Coding Units (CU) with different size by offline training. Furthermore, by this way, the partition of CUs can be resolved as a binary classification problem. Experimental results have shown that the proposed algorithm can save over 34% encoding time on average, with a negligible Bjontegaard Delta (BD)-rate increase.

Biological characterization of mesenchymal stem cells from bovine umbilical cord

Hui Xiong,Wei Jun Guan,Yue Hui Ma,Chunyu Bai,Shuang Wu,Yuhua Gao,Taofeng Lu,Qingyun Hu 한국통합생물학회 2014 Animal cells and systems Vol.18 No.1

Mesenchymal stem cells (MSCs) are multi-potential cells that are able to proliferate and differentiate into othercell types. Much research has been done on the MSCs from the umbilical cord (UCMSCs) in human, mice, andavian, but little literature has been published about these cells in big livestock. Here, we choose Luxi cattle asthe experimental animal, we describe an external culture of the UCMSCs from it and summarize the biologicalcharacteristics of these cells, e.g., morphologic appearance, surface antigens, colony-forming ability, geneexpression, and differentiation potential were detected via using immunofluorescence and reverse transcriptionpolymerase chain reaction (RT-PCR). The induced cells, osteoblast, lipoblast, hepatocyte, islet cells, andneurocyte were identified by Alizarin red staining, Oil-red-O staining, Periodic acid-schiff staining, andDithizone staining and RT-PCR detection for specific genes. Results suggest that biological characteristics ofthe UCMSCs were similar to those of MSCs previously analyzed. The primary UCMSCs were sub-cultured topassage 32, the UCMSCs expressed gene CD29, CD44, CD73, CD90, and CD166, induced cells illustratedtypical staining, and expressed specific genes, which indicate that the UCMSCs could be a novel alternativesource of MSCs for experimental and clinical applications.

Mechanisms and kinetics of zinc and iron separation enhanced by calcified carbothermal reduction for electric arc furnace dust

Jiayong Qiu,Shui Yu,Jiugang Shao,Kaiqi Zhu,Dianchun Ju,Chunyu Chen,Dexing Qi,Fei Wang,Ni Bai,Rui Mao,Xiaoming Wang 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.4

A high basicity charge prepared with electric arc furnace dust (EAFD), carbonaceous reducing agent and CaO is proposed. The mechanisms of enhancing separation of zinc and iron by calcified carbothermic reduction of the high basicity charge were analyzed by combining thermal analysis kinetics and experiment. The influences of roasting temperature, carbon ratio (nc/no, molar ratio of carbon in graphitic carbon powder to oxygen in EAFD), and CaO dosage on phase transition and dezincification ratio in EAFD were investigated. The results show that the intermediates Ca2Fe2O5 and Fe0.85−xZnxO can be produced from the zinc-iron separation of zinc ferrate during the process of calcified carbothermic reduction of EAFD. Addition of CaO and C results in the following transition pathways: ZnFe2O4+ CaO→Ca2Fe2O5+ZnO→Ca2Fe2O5+Zn(g)→CaO+Fe; Fe0.85−xZnxO+CaO→Ca2Fe2O5+FeO+ZnO→CaO+Fe+Zn(g). In the range of nc/no of 0.4–1.2 and roasting temperature of 1,000–1,100 °C, the addition of CaO can promote reduction and dezincification. Based on the Kissinger-Akahira-Sunose (KAS) and Coats-Redfern methods, the kinetic results show that the calcified carbothermic reduction process can be divided into three stages: initial stage (α=0–0.3), middle stage (α=0.3–0.45), and final stage (α=0.45–1.0). The average activation energy of the initial stage is 305.01 kJ·mol−1, and the reaction mechanism is one-dimensional diffusion. The average activation energy is 315.67 kJ·mol−1 for the middle stage and 288.22 kJ·mol−1 for the final stage. The chemical reaction equation is found to be the most suitable mechanism in the medium and final stages. It is also found that the addition of CaO can reduce the average activation energy by about 32 kJ·mol−1 and shorten the intermediate stage of the reaction.