State-Space Model Predictive Control Method for Core Power Control in Pressurized Water Reactor Nuclear Power Stations

Guoxu Wang,Jie Wu,Bifan Zeng,Zhibin Xu,Wanqiang Wu,Xiaoqian Ma 한국원자력학회 2017 Nuclear Engineering and Technology Vol.49 No.1

A well-performed core power control to track load changes is crucial in pressurized waterreactor (PWR) nuclear power stations. It is challenging to keep the core power stable at thedesired value within acceptable error bands for the safety demands of the PWR due to thesensitivity of nuclear reactors. In this paper, a state-space model predictive control (MPC)method was applied to the control of the core power. The model for core power control wasbased on mathematical models of the reactor core, the MPC model, and quadratic programming(QP). The mathematical models of the reactor core were based on neutron dynamicmodels, thermal hydraulic models, and reactivity models. The MPC model waspresented in state-space model form, and QP was introduced for optimization solutionunder system constraints. Simulations of the proposed state-space MPC control system inPWR were designed for control performance analysis, and the simulation results manifestthe effectiveness and the good performance of the proposed control method for core powercontrol.

Embedding Cobalt Into ZIF-67 to Obtain Cobalt-Nanoporous Carbon Composites as Electrode Materials for Lithium ion Battery

Zheng, Guoxu,Yin, Jinghua,Guo, Ziqiang,Tian, Shiyi,Yang, Xu The Korean Electrochemical Society 2021 Journal of electrochemical science and technology Vol.12 No.4

Lithium ion batteries (LIBs) is a kind of rechargeable secondary battery, developed from lithium battery, lithium ions move between the positive and negative electrodes to realize the charging and discharging of external circuits. Zeolitic imidazolate frameworks (ZIFs) are porous crystalline materials in which organic imidazole esters are cross-linked to transition metals to form a framework structure. In this article, ZIF-67 is used as a sacrificial template to prepare nano porous carbon (NPC) coated cobalt nanoparticles. The final product Co/NPC composites with complete structure, regular morphology and uniform size were obtained by this method. The conductive network of cobalt and nitrogen doped carbon can shorten the lithium ion transport path and present high conductivity. In addition, amorphous carbon has more pores that can be fully in contact with the electrolyte during charging and discharging. At the same time, it also reduces the volume expansion during the cycle and slows down the rate of capacity attenuation caused by structure collapse. Co/NPC composites first discharge specific capacity up to 3115 mA h/g, under the current density of 200 mA/g, circular 200 reversible capacity as high as 751.1 mA h/g, and the excellent rate and resistance performance. The experimental results show that the Co/NPC composite material improves the electrical conductivity and electrochemical properties of the electrode. The cobalt based ZIF-67 as the precursor has opened the way for the design of highly performance electrodes for energy storage and electrochemical catalysis.

A New Cassane-type Diterpene and Other Constituents from Caesalpinia minax

Huiling Liu,Guoxu Ma,Jingquan Yuan,Xiaoming Tan,Qingxia Zheng,Zhaocui Sun,Junshan Yang,Xudong Xu 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.5

A New Cassane-type Diterpene and Other Constituents from Caesalpinia minax

Liu, Huiling,Ma, Guoxu,Yuan, Jingquan,Tan, Xiaoming,Zheng, Qingxia,Sun, Zhaocui,Yang, Junshan,Xu, Xudong Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.5

Preparation of Co₃O₄/NF Anode for Lithium-ion Batteries

Tian, Shiyi,Li, Botao,Zhang, Bochao,Wang, Yang,Yang, Xu,Ye, Han,Xia, Zhijie,Zheng, Guoxu The Korean Electrochemical Society 2020 Journal of electrochemical science and technology Vol.11 No.4

Due to its characteristics of light weight, high energy density, good safety, long service life, no memory effect, and environmental friendliness, lithium-ion batteries (LIBs) are widely used in various portable electronic products. The capacity and performance of LIBs largely depend on the performance of electrode materials. Therefore, the development of better positive and negative materials is the focus of current research. The application of metal organic framework materials (MOFs) derivatives in energy storage has attracted much attention and research. Using MOFs as precursors, porous metal oxides and porous carbon materials with controllable structure can be obtained. In this paper, rod-shaped Co-MOF-74 was grown on Ni Foam (NF) by hydrothermal method, and then Co-MOF-74/NF precursor was heat-treated to obtain rodshaped Co₃O₄/NF. Ni Foam was skeleton structured, which effectively relieved. The change of internal stress changes and destroys the structural volume of the electrode material and reduces the capacity attenuation. Co₃O₄/NF composite material has a specific discharge capacity of up to 1858 mA h/g for the first time, and a reversible capacity of up to 902.4 mA h/g at a current density of 200 mA/g, and has excellent rate and impedance performance. The synthesis strategy reported in this article opens the way to design high-performance electrodes for energy storage and electrochemical catalysis.

Curcumin suppresses oxidative stress via regulation of ROS/NF-κB signaling pathway to protect retinal vascular endothelial cell in diabetic retinopathy

Huang Jiang,Yi Quanyong,You Yuhong,Chen Yao,Niu Tongtong,Yi Li,Zhang Ji,Ji Xiaoyan,Xu Guoxu,Zou Weijie,Ji Fangfang,Luo Weifeng 대한독성 유전단백체 학회 2021 Molecular & cellular toxicology Vol.17 No.3

Background The retinal vascular endothelial cells can be damaged by oxidative stress even in the early stage of diabetic retinopathy (DR). This study aimed to investigate the protective effect of curcumin on the rat retinal vascular endothelial cells (RRVECs) in high glucose circumstance. Objective The cultured RRVECs were identified and characterized by both of vWF and CD31 immunofluorescence expression. The activation of ROS/NF-κB signal pathway was examined by electrophoretic Mobility Shift Assay (EMSA), immunohistochemistry and Western blot; the apoptosis of RRVECs was tested by flow cytometry. Results We found that curcumin reduced the reactive oxygen species (ROS) and relieved the apoptosis in RRVECs exposed to the high glucose by flow cytometry. It was revealed that the increased activity of NF-κB and phosphorylated NF-κB in RRVECs induced by high glucose concentration was significantly suppressed by curcumin. Conclusion We concluded that curcumin could suppress the oxidative stress via regulation of NF-κB signal to protect the RRVECs in DR. Background The retinal vascular endothelial cells can be damaged by oxidative stress even in the early stage of diabetic retinopathy (DR). This study aimed to investigate the protective effect of curcumin on the rat retinal vascular endothelial cells (RRVECs) in high glucose circumstance. Objective The cultured RRVECs were identified and characterized by both of vWF and CD31 immunofluorescence expression. The activation of ROS/NF-κB signal pathway was examined by electrophoretic Mobility Shift Assay (EMSA), immunohistochemistry and Western blot; the apoptosis of RRVECs was tested by flow cytometry. Results We found that curcumin reduced the reactive oxygen species (ROS) and relieved the apoptosis in RRVECs exposed to the high glucose by flow cytometry. It was revealed that the increased activity of NF-κB and phosphorylated NF-κB in RRVECs induced by high glucose concentration was significantly suppressed by curcumin. Conclusion We concluded that curcumin could suppress the oxidative stress via regulation of NF-κB signal to protect the RRVECs in DR.

Computer modeling for frequency performance of viscoelastic magneto-electro-elastic annular micro/nanosystem via adaptive tuned deep learning neural network optimization

Guo, Xu,Liu, Yixian,Wang, Guanzhuo Techno-Press 2021 Advances in nano research Vol.11 No.2

The presented paper is the first attempt to apply deep learning for predicting the frequency characteristics of a magneto-electro-elastic (MEE) annular nano/microdisk (MEEAD). The optimum amount of the factors participating in the mechanism of the fully connected neural network are achieved through the optimizer based on the momentum. The positive side of the mentioned approach employed in this investigation would be due to its high accuracy along with lower epochs required for training the multi-layered network. This scrutinization would be semi-computational research that estimates the vibrational behavior of a MEEAD employing a non-classical continuum model known as the modified couple stress (MCS) model. First-order shear deformation theory (FSDT) and shell model would be provided for presenting their displacement fields. Then, Kelvin-Voight theory has been applied to model the viscoelastic foundation. Its non-classical governing equations, as well as related boundary conditions (BCs) of small-scaled MEEAD, would be achieved by considering the symmetric spinning gradient along with higher-order stress tensors for the strain energy. The provided non-classical theory would be able to capture the small scale in the MEEAD employing just one length scale of a material factor, then, the mathematical modeling of MEEAD according to the classical theory would be able to be recovered from the provided model by eliminating the material length scale factor. Ultimately, the non-classical governing equations would be solved by applying the generalized differential quadrature (GDQ) approach for multifarious BCs. Moreover, parametric research has been conducted to analyze the influences of the viscoelastic foundation, length scale factor, geometry of MEE, radial and circumferential mode number, radius ratio, and BCs on the frequency behavior of the MEEAD by applying MCST. The outcomes reveal that there would be a crucial radius ratio in which the relationship between these elements and crucial inserted voltage alters from direct to indirect relation.