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The Numerical Simulation Analysis of Flow Field in Level Control Valve of Water Storage Tank
Yaping Wang,Lei Gao,Jianghua Ge,Han Gao,Jing Zhang 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.10
Level control valve of water storage tank is installed in the outlet of tank, which control the water level of water storage tank by adjusting the water emissions, which make great significance for the safe operation of the super (super) criticality thermal power unit boiler . Complete the simulation analysis of internal flow field by the method of numerical simulation ,in order to achieve structure improvements of level control valve of water storage tank, that make level control valve of water storage tank better meet the work requirements. Establish flow channel model and mesh models of level control valve of water storage tank in various stages of the open process. Make three dimensional viscous numerical simulation of the internal complex flow field by the computational fluid dynamics software of ANSYS CFX. The error between the simulation values of the flow coefficient and the theoretical values , trial values is less than 5% ,which verifies the correctness of the simulation results . Get pressure contour , velocity streamline diagrams and outlet mass flow of level control valve of water storage tank in various stages of the open process. According to the pressure contours and velocity streamline diagrams, make detailed analysis of the flow field of level control valve of water storage tank. According to the dates of outlet mass flow, fit the flow characteristic curve of level control valve of water storage tank. Provide a theoretical basis for the structural design of level control valve of water storage tank.
Han-Lu Gao,Xuan Wang,Hong-Ru Sun,Jun-De Zhou,Shang-Qun Lin,Yu-Hang Xing,Lin Zhu,Hai-Bo Zhou,Ya-Shuang Zhao,Qiang Chi,Yu-Peng Liu 거트앤리버 소화기연관학회협의회 2018 Gut and Liver Vol.12 No.2
Background/Aims: Methylation status plays a causal role in carcinogenesis in targeted tissues. However, the relationship between the DNA methylation status of multiple genes in blood leukocytes and colorectal cancer (CRC) susceptibility as well as interactions between dietary factors and CRC risks are unclear. Methods: We performed a case-control study with 466 CRC patients and 507 cancer-free controls to investigate the association among the methylation status of individual genes, multiple CpG site methylation (MCSM), multiple CpG site heterogeneous methylation and CRC susceptibility. Peripheral blood DNA methylation levels were detected by performing methylation-sensitive high-resolution melting. Results: Total heterogeneous methylation of CA10 and WT1 conferred a significantly higher risk of CRC (adjusted odds ratio [ORadjusted], 5.445; 95% confidence interval [CI], 3.075 to 9.643; ORadjusted, 1.831; 95% CI, 1.100 to 3.047; respectively). Subjects with high-level MCSM (MCSM-H) status demonstrated a higher risk of CRC (ORadjusted, 4.318; 95% CI, 1.529 to 12.197). Additionally, interactions between the high-level intake of fruit and CRH, WT1, and MCSM on CRC were statistically significant. Conclusions: The gene methylation status of blood leukocytes may be associated with CRC risk. MCSM-H of blood leukocytes was associated with CRC, especially in younger people. Some dietary factors may affect hypermethylation status and influence susceptibility to CRC.
A High Precision and Fast Alignment Method Based on Binocular Vision
Han Gao,Fei Shen,Feng Zhang,Zhengtao Zhang 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.9
Alignment tasks for precision electronics manufacturing require high accuracy and low time consumption. However, in the current industrial environment, multiple servo alignment operations are often required to achieve the desired accuracy targets, which is time-consuming. In this paper, a high precision, fast alignment method based on binocular vision is proposed, which allows the accurate movement of the workpiece to the target position in only one alignment operation, without the need for a standard calibration board. Firstly, a calibration method of the telecentric lens camera is proposed based on an improved nonlinear damped least-squares method to establish the relationship between the image coordinate system and the local world coordinate system in the binocular vision system. Secondly, in order to transform the coordinates from the local world coordinate system to a unified coordinate system with the platform’s rotation center as the origin, an angle constraint-based rotation center calibration method is proposed. Thirdly, a two-stage feature point detection method based on shape matching is proposed to detect the feature points of the workpiece. Based on these, the position and pose of the workpiece are obtained. Then the alignment commands are calculated based on the current and the target position and pose of the workpiece, enabling the accurate alignment to be accomplished in one operation. Finally, taking the mobile phone’s cover glass alignment task as an example, a series of calibration and alignment experiments were carried out. The experiments and results show that the alignment errors are within ± 0.020 mm and the time taken to calculate alignment commands is less than 20 ms, which demonstrates the effectiveness of the proposed method.
Synthesis and Viscoelastic Behavior of Non-Stoichiometric Spinel Ferrite Particle Suspension
Han, Jae Kyeong,Han, Wen Jiao,Gao, Chun Yan,Dong, Yu Zhen,Choi, Hyoung Jin IEEE 2018 IEEE transactions on magnetics Vol.54 No.11
<P>Magnetorheological (MR) fluid with tunable and reversible phase transition is one of the most promising smart materials for engineering applications. In this paper, to improve the MR performance of ferrites, non-stoichiometric Zn-doped spinel ferrite (Zn<SUB>0.417</SUB>Fe<SUB>2.583</SUB>O<SUB>4</SUB>) nanoparticles with a high saturation magnetization and a truncated octahedron-like shape were synthesized using a thermal decomposition process. The crystallographic structure was analyzed using X-ray diffraction and field emission transmission electron microscope image. The Zn<SUB>0.417</SUB>Fe<SUB>2.583</SUB>O<SUB>4</SUB> had a high saturation magnetization value of 101 <TEX>$\text {A}\cdot \text {m}^{2}$</TEX>/kg at 933 kA/m, showing higher saturation magnetization than other ferrites. The MR characteristics of the Zn<SUB>0.417</SUB>Fe<SUB>2.583</SUB>O<SUB>4</SUB> particles suspended in silicone oil were studied using a rotation rheometer under various magnetic field strengths. This MR fluid exhibited typical MR characteristics, and its flow curves were fit well with the Herschel–Bulkley model.</P>
SOI radiation‑hardened 300 V half‑bridge date driver IC design with high dv/dt noise immunity
Yuexin Gao,Xiaowu Cai,Zhengsheng Han,Yun Tang,Liqiang Ding,Ruirui Xia,Mali Gao,Fazhan Zhao 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.5
Noise immunity is a critical index of high-voltage half-bridge gate driver integrated circuits (IC). Various noise cancelation technologies have been proposed to improve dv/dt noise immunity with sacrifices in terms of area and propagation delay time. Besides, when it is applied to an inductive load, the half-bridge driver is vulnerable to negative surges at the VS terminal, which is the offset ground of the high-side channel. A 300 V half-bridge gate driver IC with noise rejection module is designed in this paper. The noise immunity can be improved to 87.5 V/ns. The VS negative swing region can be extended to − 5.1 V. In addition, the proposed driver IC can work normally at a working frequency of 500 kHz and the delay matching time between the high-side and the low-side is less than 4 ns. The propagation delay time of the high-side channel is measured at 71.6 ns. Furthermore, gamma ray irradiation experimental results show that the proposed structure presents a good radiation tolerance of 100 krad (Si). The presented half-bridge gate driver IC is fabricated with the silicon-on-insulator (SOI) bipolar-CMOS-DMOS (BCD) process, which occupied an area of 1.86 mm2.
Zhiqiang Han,Gang Han,Zhiyong Wang,Bonian Shui,Tianxiang Gao 한국유전학회 2015 Genes & Genomics Vol.37 No.5
Amplified fragment length polymorphism markers were used to estimate the genetic divergence and genetic structure of Lateolabrax maculatus, L. japonicus and their possible hybrid populations in the Northwestern Pacific. Ninety one individuals were sampled from nine localities including two putative hybrid samples across the distribution range of the two species. Five primer combinations generated a total of 423 loci among 91 individuals of L. maculatus and L. japonicus, 266 of which were polymorphic (62.88 %). The percentage of polymorphic loci in three populations of L. maculatus and five populations of L. japonicus ranged from 31.96 % (Beihai) to 37.94 % (Weihai), 31.05 % (Ishikawa) to 49.29 % (Yatsushiro Sea), respectively. The UPGMA tree constructed with individuals of both species indicated reciprocal monophyletic relationship between L. japonicus and L. maculatus. Hybrid individuals between the two species in Ariake Sea and Yatsushiro Sea were identified by UPGMA tree and principal component analysis (PCA). The sympatry of two clades in the Yatsushiro Sea gave the first evidence of possible reproductive isolation between hybrid and L. japonicus. AMOVA analysis and pairwise FST revealed significant genetic differentiation within both species, indicating limited dispersal ability in two species. Historical isolation coupled with low dispersal ability was responsible for the genetic divergence between species and significant genetic structure in the two species.