Comparative Study of DC Breakdown and Space Charge Characteristics of Insulation Paper Impregnated with Natural Ester and Mineral Oil

Jian Hao,Run-Hao Zou,Rui-Jin Liao,Li-Jun Yang,Qiang Liao,Meng-Zhao Zhu 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.4

Natural ester is a suitable substitute for mineral oil and has been widely used in AC transformer in many countries. In order to further application of natural ester in direct current (DC) equipment, it is needed to investigate its long term insulation property under DC condition. In this paper, a thermal ageing experiment was conducted for both mineral oil-paper and natural ester-paper insulation. The DC breakdown and space charge characteristics of insulation paper impregnated with natural ester and mineral oil was compared. Results show that the resistivity of the paper immersed in natural ester and mineral oil both increase as the ageing goes on. While insulation paper impregnated with natural ester has higher resistivity and DC breakdown voltage than the paper impregnated with mineral oil. The DC breakdown voltage for the oil impregnated insulation paper being DC prestressing is higher than that without pre-stressing. The average DC breakdown field strength difference between the test with pre-stressing and without pre-stressing clearly shows that there is an apparent enhancement effect for the homo-charge injection on the DC breakdown.

Optimal trajectory generation for a quadrotor with a cable-suspended payload considering payload angle constraint

Jianhao Su(소건호),Jeong Hyeon Bak(박정현),Jong Hyeon Park(박종현) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.5

Method for extracting motor impedance characteristics online

Wang, Jianhao,Chen, Wei The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.6

Due to increases in switching frequency, the electromagnetic interference of motor drive systems has been receiving more attention. In a motor drive system, the devices in the inverter produce serious electromagnetic interference during high-frequency switching. It is necessary to model the motor drive system to predict the electromagnetic interference level. Extraction of the motor impedance characteristic is necessary for the modeling of a motor drive system. At present, most research only studies the measurement method of a motor in the static state. However, motor impedance characteristics in the static state cannot represent motor impedance characteristics in operation. In this paper, an online measurement method of motor impedance characteristics is proposed. For the three-phase asymmetric circuit caused by modulation, the motor impedance characteristics in operation are calculated by establishing Kirchhoff voltage equations. A precision power scope PX8000 is used to measure the harmonic components of single-phase voltage, single-phase current, and common-mode current. The time-delay difference of the precision power scope PX8000 between different probes is also considered. Experiments prove that the time-delay difference does not affect the measurement results. Through comparing the motor impedance characteristics measured by different filters, the method of extracting the motor impedance characteristics online is validated. Finally, the motor impedance characteristics in the static state and the motor impedance characteristics of online extraction are experimentally compared. The motor impedance characteristics of the online extraction method proposed in this paper have more advantages than traditional methods.

Kernel quaternion principal component analysis and its application in RGB-D object recognition

Chen, Beijing,Yang, Jianhao,Jeon, Byeungwoo,Zhang, Xinpeng Elsevier 2017 Neurocomputing Vol.266 No.-

<P><B>Abstract</B></P> <P>While the existing quaternion principal component analysis (QPCA) is a linear tool developed mainly for processing linear quaternion signals, the quaternion representation (QR) used in QPCA creates redundancy when representing a color image signal of three components by a quaternion matrix having four components. In this paper, the kernel technique is used to improve the QPCA as kernel QPCA (KQPCA) for processing nonlinear quaternion signals; in addition, both RGB information and depth information are considered to improve QR for representing RGB-D images. The improved QR fully utilizes the four-dimensional quaternion domain. We first provide the basic idea of three types of our KQPCA and then propose an algorithm for RGB-D object recognition based on bidirectional two-dimensional KQPCA (BD2DKQPCA) and the improved QR. Experimental results on four public datasets demonstrate that the proposed BD2DKQPCA-based algorithm achieves the best performance among seventeen compared algorithms including other existing PCA-based algorithms, irrespective of RGB object recognition or RGB-D object recognition. Moreover, for all compared algorithms, consideration of both RGB and depth information is shown to achieve better performance in object recognition than considering only RGB information.</P>

Effect of Monascus as a Nitrite Substitute on Color, Lipid Oxidation, and Proteolysis of Fermented Meat Mince

Xiang Yu,Haizhou Wu,Jianhao Zhang 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.2

Monascus spp. are fungi, traditionally eaten in Asian countries, that have the the potential to be used as a nitrite substitute in meat-product processing. Effects of using Monascus ruber MJ-1 as a nitrite substitute on color, lipid oxidation and proteolysis of fermented meat mince were investigated in this study. After 4 days of fermentation, a* and L* values for the samples were significantly higher and lower than the values for the control, respectively; however, b* values were significantly lower than that of the control throughout the fermentation process (p<0.05). Furthermore, Monascus ruber MJ-1 fermentation decreased the thiobarbituric acid reactive substances (TBARs) value and increased the myofibril fragmentation index (MFI) value of meat mince significantly (p<0.05). SDS-PAGE results further indicated that myofibrillar proteins were degraded during fermentation, while sarcoplasmic proteins were not. These results suggest prospects for the broad application of Monascus as a nitrite substitute in meat processing.

New Error Control Algorithms for Residue Number System Codes

Hanshen Xiao,Hari Krishna Garg,Jianhao Hu,Guoqiang Xiao 한국전자통신연구원 2016 ETRI Journal Vol.38 No.2

We propose new error control algorithms for Redundant Residue Number System (RRNS) and Residue Number System Product codes (RNS-PC) under a unified mathematical framework. These algorithms are based on search techniques for the ‘error value’ in a set containing all the possible error values in an ordered manner. They have significant computational advantages over existing methods with a computational complexity of t . O(log2 n + log2 m) comparison operations. For a RRNS, t is its error correcting capability, n is the total number of modulii, and m is their geometric average. Further, the algorithms do not require modular arithmetic operations. A refinement is described that avoids the modular operation required by the Chinese Remainder Theorem (CRT) in the first step of decoding algorithms with an increase in complexity by log2 n comparison operations.

Circumnavigation of a Moving Target in 3D by Multi-agent Systems with Collision Avoidance: An Orthogonal Vector Fields-based Approach

Hang Zhong,Yaonan Wang,Zhiqiang Miao,Jianhao Tan,Ling Li,Hui Zhang,Rafael Fierro 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.1

The problem of circumnavigating a moving target in a three dimensional setting by a network of agentswhile avoiding inter-agent collisions is addressed in this paper. A distributed control strategy is proposed for themulti-agent system to achieve three objectives: reaching the target plane with predesigned orientation, circulatingaround the target with prescribed radius, and avoiding collisions among agents. After representing the controlobjectives by three potential functions, the gradient fields of which are orthogonal to each other, the control lawthen is developed using the gradient vector field-based approach. The novelty of the proposed controller lies in theorthogonality of the vector fields, which decouples the control objectives and ensures global asymptotic convergenceto the desired motion, subject to some mild initial condition constraints. The stability and convergence analysis arepresented using Lyapunov tools, and the effectiveness of the proposed control strategy is demonstrated throughnumerical simulations.

Microwave-assisted functionalization of polyurethane surface for improving blood compatibility

Deqiang You,Mei Tu,Rong Zeng,Hao Liang,Weizhong Mai,Jianhao Zhao,Zhengang Zha 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.5

In order to improve the hemocompatibility of polyurethane (PU), we report a rapid and efficient two-step approach to graft poly(ethylene glycol) (PEG) onto PU surface by a microwave-assisted method,involving diphenylmethane diisocyanate (MDI) – functionalization and subsequent PEG coupling. Compared with conventional heating, the effects of solvent, time and MDI concentrations on the microwave-assisted MDI-functionalization, and the effect of time on the microwave-assisted PEG coupling were studied. PEGs with different molecular weights were successfully grafted onto PU surface under the optimum microwave-assisted conditions within only 20 min, and characterized by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and chemical titration. The hydrophilicity and in vitro blood compatibility of the surfaces were evaluated by water contact angle measurements, blood coagulation time (whole blood clotting time and prothrombin time) and platelet adhesion tests, respectively. All the PU-PEG surfaces had improved surface wettability and hemocompatibility. The results suggested that microwave-assisted functionalization may be a promising method for rapidly and effectively decorating polyurethane surfaces.

Effects of feeding different levels of dietary corn silage on growth performance, rumen fermentation and bacterial community of post-weaning dairy calves

Li Lingyan,Qu Jiachen,Zhu Huan,Liu Yuqin,Wu Jianhao,Shao Guang,Guan Xianchao,Qu Yongli 아세아·태평양축산학회 2024 Animal Bioscience Vol.37 No.2

Objective: The objective of this study was to evaluate the growth performance, rumen fermentation parameters and bacterial community of post-weaning dairy calves in response to five diets varying in corn silage (CS) inclusion.Methods: A total of forty Holstein weaned bull calves (80±3 days of age;128.2±5.03 kg at study initiation) were randomized into five groups (8 calves/group) with each receiving one of five dietary treatments offered as total mixed ration in a 123-d feeding study. Dietary treatments were control diet (CON; 0% CS dry matter [DM]); Treatment 1 (T1; 27.2% CS DM); Treatment 2 (T2; 46.5% CS DM); Treatment 3 (T3; 54.8% CS DM); and Treatment 4 (T4; 67.2% CS DM) with all diets balanced for similar protein and energy concentration.Results: Results showed that calves offered CS had greater average daily gain, body length and chest depth growth, meanwhile altered rumen fermentation indicated by decreased rumen acetate concentrations. Principal coordinate analysis showed the rumen bacterial community structure was affected by varying CS inclusion diets. <i>Bacteroidetes</i> and <i>Firmicutes</i> were the predominant bacterial phyla in the calf rumens across all treatments. At the genus level, the abundance of <i>Bacteroidales_RF16_group</i> was increased, whereas <i>Unclassified_ Lachnospiraceae</i> was decreased for calves fed CS. Furthermore, Spearman’s correlation test between the rumen bacteria and rumen fermentation parameters indicated that <i>Bacteroidales_RF16_group</i> and <i>Unclassified Lachnospiraceae</i> were positively correlated with propionate and acetate, respectively.Conclusion: The results of the current study suggested that diet CS inclusion was beneficial for post-weaning dairy calf growth, with 27.2% to 46.5% CS of diet DM recommended to achieve improved growth performance. <i>Bacteroidales_RF16_group</i> and <i>Unclassified Lachnospiraceae</i> play an important role in the rumen fermentation pattern for post-weaning calves fed CS.

Influence of Partial Replacement of NaCl with KCl on Formation of Volatile Compounds in Jinhua Ham during Processing

Yingyang Zhang,Haizhou Wu,Jing Tang,Mingming Huang,Jianying Zhao,Jianhao Zhang 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.2

The influence of partial replacement of NaCl with KCl on formation of volatile compounds during Jinhua ham processing was evaluated using GC/MS system. Jinhua ham was treated with either 100% NaCl (I) or 60% NaCl and 40% KCl (II). Formation of volatile compounds increased in Jinhua hams during processing for both salt formulations, particularly at the end of the salting period. There were differences in volatile compound formation between formulations I and II after 45 days of processing. Contents of lipid-derived volatiles (hexanal) and Strecker aldehydes (2-methylbutanal and 3- methylbutanal) were higher in Jinhua hams treated with formulation II after 45 days of processing. Partial salt replacement of NaCl with KCl changed formation of volatile compounds in Jinhua hams and may have affected the flavor of finished products.