Analytical and Experimental Validation of Parasitic Components Influence in SiC MOSFET Three-Phase Grid-connected Inverter

Liu, Yitao,Song, Zhendong,Yin, Shan,Peng, Jianchun,Jiang, Hui The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

With the development of renewable energy, grid-connected inverter technology has become an important research area. When compared with traditional silicon IGBT power devices, the silicon carbide (SiC) MOSFET shows obvious advantages in terms of its high-power density, low power loss and high-efficiency power supply system. It is suggested that this technology is highly suitable for three-phase AC motors, renewable energy vehicles, aerospace and military power supplies, etc. This paper focuses on the SiC MOSFET behaviors that concern the parasitic component influence throughout the whole working process, which is based on a three-phase grid-connected inverter. A high-speed model of power switch devices is built and theoretically analyzed. Then the power loss is determined through experimental validation.

Thermal Field Characteristic Analysis of Steel Bridge Deck During High-temperature Asphalt Pavement Paving

Yang Liu,Zhendong Qian,Hanzhou Hu 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.7

The steel bridge deck undergoes significant temperature changes during the high-temperature paving of asphalt pavement, and the non-uniform thermal field distribution herein affects the performance of pavement composite system. In this paper, the thermal field characteristic of the steel bridge deck during asphalt pavement paving was presented based on in-situ monitoring of the Tongling Yangtze River Bridge (TL Bridge) and numerical simulation. Firstly, the monitoring schemes were proposed to monitor the temperature changes of the steel bridge deck during the paving process, and the 3-D temperature distribution of the steel bridge deck was summarized. Secondly, a thermal field model of steel box girder was established according to the transient temperature field theory, and the element deletion method was used to simulate the process of paving construction. Subsequently, the thermal field model was validated by the monitoring results. Thirdly, the validated thermal field model was used to evaluate the sensitive factors that could affect the temperature distribution of the steel bridge deck during asphalt pavement paving. Finally, the critical temperature load formula was fitted, in which the sensitive factors were considered by introducing sensitive parameters.

Analytical and Experimental Validation of Parasitic Components Influence in SiC MOSFET Three-Phase Grid-connected Inverter

Yitao Liu,Zhendong Song,Shan Yin,Jianchun Peng,Hui Jiang 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

With the development of renewable energy, grid-connected inverter technology has become an important research area. When compared with traditional silicon IGBT power devices, the silicon carbide (SiC) MOSFET shows obvious advantages in terms of its high-power density, low power loss and high-efficiency power supply system. It is suggested that this technology is highly suitable for three-phase AC motors, renewable energy vehicles, aerospace and military power supplies, etc. This paper focuses on the SiC MOSFET behaviors that concern the parasitic component influence throughout the whole working process, which is based on a three-phase grid-connected inverter. A high-speed model of power switch devices is built and theoretically analyzed. Then the power loss is determined through experimental validation.

Thermo-Mechanical Coupling Analysis of the Actuating Mechanism in a High Speed Press

Jin Cheng,Zhendong Zhou,Yixiong Feng,Zhenyu Liu,Yangyan Zhang 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.5

In order to ensure the manufacturing precision of an ultra-precision high speed press, an integrated thermo-mechanical coupling model of its actuating mechanism is proposed, which includes the mechanical models of the slider and crankshaft, the thermal models for calculating the heat generation powers at different bearings as well as the heat transfer and heat dissipation in the actuating mechanism. The validity of the proposed thermo-mechanical coupling model is verified by a thermal equilibrium experiment when the press operates under the full load of 3000kN at 300 rpm. A sensitivity analysis is conducted to investigate the simulation errors resulting from the variation of the ambient temperature, the results of which demonstrate that the average ambient temperature should be applied for improving simulation accuracy. Then the thermal stiffness of the actuating mechanism and the thermo-mechanical coupling characteristics of different parts are analyzed by the proposed model with the average ambient temperature applied. The influences of the thermally induced loads on the thermal stiffness are discussed in detail. It is concluded that the temperature rise of the actuating mechanism in the stamping process of a high speed press should be fully considered in the design phase for ensuring its manufacturing precision.

Discovery of Endothelium and Mesenchymal Properties of Primo Vessels in the Mesentery

Ping, An,Zhendong, Su,Jingxing, Dai,Yaling, Liu,Bae, Kyung-Hee,Shiyun, Tan,Hesheng, Luo,Soh, Kwang-Sup,Ryu, Yeon Hee,Kim, Sungchul Hindawi Publishing Corporation 2013 Evidence-based Complementary and Alternative Medic Vol.2013 No.-

<P>Recent evidences demonstrated that endothelial-to-mesenchymal transition (EndMT) has a crucial role in cancer and is recognized as a unique source of cancer-associated fibroblasts (CAFs). Primo vascular system (PVS) is a new circulatory system which may play an important role in cancer metastasis and regeneration. In the current study, we applied previously established time-saving method to identify primo vessels and further investigated the immunocytochemical properties of primo vessels. Both primo vessels and primary primo vessel cells in the mesentery expressed endothelial markers and fibroblast markers. Double-labeling experiments demonstrated that endothelial and fibroblast markers are coexpressed in primo vessels. In addition, under the stimulation of TGF-<I>β</I>1 <I>in vitro,</I> primary primo vessel cells differentiated into fibroblasts. Therefore, we found that primo vessels in the mesentery had a transitional structure between endothelium and mesenchymal. This is a new finding of EndMT in normal postnatal animals.</P>

Seroprevalence and associated risk factors of pseudorabies in Shandong province of China

Dongfang Hu,Lin Lv,Zhendong Zhang,Yihong Xiao,Sidang Liu 대한수의학회 2016 Journal of Veterinary Science Vol.17 No.3

A cross-sectional serological study was conducted in Shandong province of China to determine the seroprevalence and risk factors associated with seropositivity due to pseudorabies virus (PRV) infection in small- and medium-sized farrow-to-finish herds following outbreaks of variant PRV strains. A total of 6,035 blood samples from 224 randomly selected herds were screened. The results showed that 25.0% of the herds and 56.7% of the serum samples were seropositive for field strains of PRV. Herds consisting of 50–100 breeding sows had higher herd seroprevalence and serum sample seroprevalence than larger herds. Both the highest herd seroprevalence and highest serum sample seroprevalence were observed in western Shandong, followed northern Shandong. Based on univariate analysis, the following risk factors were utilized in subsequent multivariable logistic regression analysis: region, herd size, weight of purchased gilts, and all-in/all-out practice. Upon multivariate analysis, region, herd size, weight of purchased gilts and all-in/all-out practice were significantly associated with PRV herd seropositivity. These findings indicate that we are facing a serious situation in the prevention and control of pseudorabies. The results could help predict the next outbreak and set out control measures.

A general active-learning method for surrogate-based structural reliability analysis

Congyi Zha,Zhili Sun,Jian Wang,Chenrong Pan,Zhendong Liu,Pengfei Dong 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.83 No.2

Surrogate models aim to approximate the performance function with an active-learning design of experiments (DoE) to obtain a sufficiently accurate prediction of the performance function’s sign for an inexpensive computational demand in reliability analysis. Nevertheless, many existing active-learning methods are limited to the Kriging model, while the uncertainties of the Kriging itself affect the reliability analysis results. Moreover, the existing general active-learning methods may not achieve a fully satisfactory balance between accuracy and efficiency. Therefore, a novel active-learning method GLM- CM is constructed to yield the issues, which conciliates several merits of existing methods. To demonstrate the performance of the proposed method, four examples, concerning both mathematical and engineering problems, were selected. By benchmarking obtained results with literature findings, various surrogate models combined with the proposed method not only provide an accurate reliability evaluation while highly alleviating the computational burden, but also provides a satisfactory balance between accuracy and efficiency compared to the other reliability methods.

Associations between the 1-deoxy-d-xylulose-5-phosphate synthase gene and aroma in different grapevine varieties

Xiaoxu Yang,Yinshan Guo,Junchi Zhu,Guangli Shi,Zaozhu Niu,Zhendong Liu,Kun Li,Xiuwu Guo 한국유전학회 2017 Genes & Genomics Vol.39 No.10

Linalool, α-terpineol, citronellol, nerol, geraniol, and geraniol acid are the main monoterpenes in the grapevine (Vitis vinifera L.) with the concentrations of these substances differing in different varieties. This research performed association analyses using a core collection of 92 grape accessions to identify causal SNPs in the gene 1-deoxy-d-xylulose-5-phosphate synthase (VvDXS), a regulator of monoterpene metabolism. We evaluated the free linalool, α-terpineol, citronellol, nerol, geraniol, and geraniol acid content of 92 grape varieties in two consecutive years (2014 and 2015). Twenty-two SNPs were found in the VvDXS coding region and were used in an association analysis. We found that the linalool, α-terpineol, nerol, and geraniol acid levels were higher in varieties with a G/T genotype at P852 than in varieties with other genotypes at this site. Additionally, we found a novel polymorphism site P1678 (A/G) with a functional effect on terpenoid content that was related to the regulation of gene transcription. This study revealed the relationship between VvDXS and aroma, with the identified polymorphism site potentially assisting in the screening of aroma compounds at early stages in fruit development in grapevines.