Adaptive Multiple MPC for a Wind Farm with DFIG

Xiao-ming LI,Xi ZHANG,Zhong-wei LIN,Yu-guang NIU,Ming-yang LI,Noel Vishal Nathan 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.5

For low investment and flexible control, doubly fed induction generator (DFIG) is becoming the dominant type that is been used in the wind farms (WFs) today. The report researches about the rotor-side controller of DFIG where all design is based on the single machine infinite bus (SMIB) model. The interactions between the different generators have not been considered in the SMIB model, and the desired performance cannot be obtained by using the controller based on this model. In this situation, an adaptive decentralized-coordinated multiple model predictive control (ADM-MPC) is proposed. First, the interaction measurement method is developed to obtain the interaction measurement model of DFIG, where the interactions between the different generators have been considered. Next, an adaptive multiple MPC based on the obtained interaction measurement method of DFIG is employed to control the rotor-side converter of DFIG. In order to cope with the stochastic disturbance of wind turbine, the augment state structure is employed to improve the tracking control performance. An artificial neural network (ANN) trained online is employed as a weighting controller to cope with the nonlinearities and large operating range of DFIG. A simple, generic renewable power system (RPS) is used to demonstrate contributions. The results of both dominant eigenvalue analysis and time response simulations are represented to illustrate contributions to system damping and transient stability that the DFIG based WF can make with the proposed ADM-MPC controller.

Electronic properties and reactivity patterns of high‐valent metal‐oxo species of Mn, Fe, Co, and Ni

Li Xiao‐Xi,Cho Kyung‐Bin,Nam Wonwoo 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.11

Density functional theory (DFT) calculations were performed for a series of significant terminal high-valent metal-oxo complexes, where the metals are Mn, Fe, Co, and Ni, to reveal their electronic property and reactivity patterns toward the inert C H bond activation. We found that as the metal center changes from Mn to Ni, the bond strength of metal-oxo decreases while the oxyl character of the oxygen increases, which suggests an increase in the hydrogen-abstraction reactivity. This prediction was further strengthened by theoretical reactivity studies, that is, the reactivities of these four metal-oxo species toward inert C H bond followed an order of MnO ≈ FeO CoO- < NiO. At the orbital level, it was found that three different electron transfer mechanisms were active among these four species. Thus, this study would provide an explanation and intuitive clues for chemists to understand the nature of the high-valent late transition metal-oxo species.

Adaptive Multiple MPC for a Wind Farm with DFIG: a Decentralized-Coordinated Approach

LI, Xiao-ming,ZHANG, Xi,LIN, Zhong-wei,NIU, Yu-guang,LI, Ming-yang,Nathan, Noel Vishal The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.5

High-Spin Mn(V)-Oxo Intermediate in Nonheme Manganese Complex-Catalyzed Alkane Hydroxylation Reaction: Experimental and Theoretical Approach

Li, Xiao-Xi,Guo, Mian,Qiu, Bin,Cho, Kyung-Bin,Sun, Wei,Nam, Wonwoo American Chemical Society 2019 Inorganic Chemistry Vol.58 No.21

<P>Mononuclear nonheme manganese complexes are highly efficient catalysts in the catalytic oxidation of hydrocarbons by hydrogen peroxide in the presence of carboxylic acids. Although high-valent Mn(V)-oxo complexes have been proposed as the active oxidants that afford high regio-, stereo-, and enantioselectivities in the catalytic oxidation reactions, the importance of the spin state (e.g., <I>S</I> = 0 or 1) of the proposed Mn(V)-oxo species is an area that requires further study. In the present study, we have theoretically demonstrated that a mononuclear nonheme Mn(V)-oxo species with an <I>S</I> = 1 ground spin state is the active oxidant that effects the stereo- and enantioselective alkane hydroxylation reaction; it is noted that synthetic octahedral Mn(V)-oxo complexes, characterized spectroscopically and/or structurally, possess an <I>S</I> = 0 spin state and are sluggish oxidants. In an experimental approach, we have investigated the catalytic hydroxylation of alkanes by a mononuclear nonheme Mn(II) complex, [(<I>S</I>-PMB)Mn<SUP>II</SUP>]<SUP>2+</SUP>, and H<SUB>2</SUB>O<SUB>2</SUB> in the presence of carboxylic acids; alcohol is the major product with high stereo- and enantioselectivities. A synthetic Mn(IV)-oxo complex, [(<I>S</I>-PMB)Mn<SUP>IV</SUP>(O)]<SUP>2+</SUP>, is inactive in C-H bond activation reactions, ruling out the Mn(IV)-oxo species as an active oxidant. DFT calculations have shown that a Mn(V)-oxo species with an <I>S</I> = 1 spin state, [(<I>S</I>-PMB)Mn<SUP>V</SUP>(O)(OAc)]<SUP>2+</SUP>, is highly reactive and capable of oxygenating the C-H bond via oxygen rebound mechanism; we propose that the triplet spin state of the Mn(V)-oxo species results from the consequence of breaking the equatorial symmetry due to the binding of an equatorial oxygen from an acetate ligand. Thus, the present study reports that, different from the previously reported <I>S</I> = 0 Mn(V)-oxo species, Mn(V)-oxo species with a triplet ground spin state are highly reactive oxidants that are responsible for the regio-, stereo-, and enantioselectivities in the catalytic hydroxylation of alkanes by mononuclear nonheme manganese complexes and terminal oxidants.</P><P>It is theoretically demonstrated that a mononuclear nonheme Mn(V)-oxo species with an <I>S</I> = 1 ground spin state, [(<I>S</I>-PMB)Mn<SUP>V</SUP>(O)(OAc)]<SUP>2+</SUP>, is highly reactive and capable of oxygenating the C−H bond via oxygen rebound mechanism. Thus, it is proposed that a triplet spin state (<I>S</I> = 1) Mn(V)-oxo intermediate is generated as an active oxidant that is responsible for the regio-, stereo-, and enantioselectivities in the catalytic hydroxylation of alkanes by nonheme manganese catalysts and terminal oxidants.</P> [FIG OMISSION]</BR>

Synthesis of Phosphorous Phenanthrene/L-Tryptophan Flame Retardant for Enhanced Flame Retardancy of Epoxy Resins

Li Li,Fenglin Hua,Hui Xi,Jing Yang,Ting Xiao,Rui Zuo,Xueqing Xu,Zhiwang Yang,Ziqiang Lei 한국고분자학회 2022 Macromolecular Research Vol.30 No.12

A new type of phosphorus-containing intrinsic flame retardant was prepared with L-tryptophan (L-Trp) and 9,10-dihydro-9-oxa-10-phosphorbenzophenanthrene- 10-oxide (DOPO) as the main components. The Schiff base from the reaction of 1,4-terephthalaldehyde and L-tryptophan provides active sites, and then the phosphorous compound, DOPO, is successfully introduced into the Schiff base to synthesize L-Trp-DOPO flame retardant. The intrinsic flame retardant property of LTrp- DOPO comes from the reaction of carbonyl groups and the epoxy groups in epoxy resin (EP) matrix. The prepared L-Trp-DOPO flame retardant can efficiently improve the flame retardancy and smoke suppression of the base material of EP. Cone calorimetric test (CCT) of EP/L-Trp-DOPO composite material was carried out. The data showed that the peak heat release rate (pk-HRR) value was reduced by 50.8% (from 1459 kW/m2 to 717 kW/m2), the THR value reduced by 78.3%, and the limiting oxygen index (LOI) value was increased by 24%. The addition of new flame retardant greatly reduced the release of toxic CO gas. The flame retardant mechanism was explored, and it can be found that after thermal decomposition of L-Trp- DOPO a dense carbon layer can be produced to isolate the fire source. In addition, during the combustion process, L-Trp-DOPO will produce phosphorus-containing free radicals which will quench the active free radicals in the gas phase and dilute the combustible gas. The prepared L-Trp-DOPO flame retardant has a flame retardant effect in both the condensed phase and the gas phase during the combustion process.

Neutrophil Count and the Inflammation-based Glasgow Prognostic Score Predict Survival in Patients with Advanced Gastric Cancer Receiving First-line Chemotherapy

Li, Qing-Qing,Lu, Zhi-Hao,Yang, Li,Lu, Ming,Zhang, Xiao-Tian,Li, Jian,Zhou, Jun,Wang, Xi-Cheng,Gong, Ji-Fang,Gao, Jing,Li, Jie,Li, Yan,Shen, Lin Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.2

Purpose: To explore the value of systemic inflammatory markers as independent prognostic factors and the extent these markers improve prognostic classification for patients with inoperable advanced or metastatic gastric cancer (GC) receiving palliative chemotherapy. Methods: We studied the prognostic value of systemic inflammatory factors such as circulating white blood cell count and its components as well as that combined to form inflammation-based prognostic scores (Glasgow Prognostic Score (GPS), Neutrophil-Lymphocyte Ratio (NLR), Platelet Lymphocyte Ratio (PLR), Prognostic Index (PI) and Prognostic Nutritional Index (PNI)) in 384 patients with inoperable advanced or metastatic gastric cancer (GC) receiving first-line chemotherapy. Univariate and multivariate analyses were performed to examine the impact of inflammatory markers on overall survival (OS). Results: Univariate analysis revealed that an elevated white blood cell, neutrophil and/or platelet count, a decreased lymphocyte count, a low serum albumin concentration, and high CRP concentration, as well as elevated NLR/PLR, GPS, PI, PNI were significant predictors of shorter OS. Multivariate analysis demonstrated that only elevated neutrophil count (HR 3.696, p=0.003) and higher GPS (HR 1.621, p=0.01) were independent predictors of poor OS. Conclusion: This study demonstrated elevated pretreatment neutrophil count and high GPS to be independent predictors of shorter OS in inoperable advanced or metastatic GC patients treated with first-line chemotherapy. Upon validation of these data in independent studies, stratification of patients using these markers in future clinical trials is recommended.

ANNs on Co-occurrence Matrices for Mobile Malware Detection

( Xi Xiao ),( Zhenlong Wang ),( Qi Li ),( Qing Li ),( Yong Jiang ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.7

Android dominates the mobile operating system market, which stimulates the rapid spread of mobile malware. It is quite challenging to detect mobile malware. System call sequence analysis is widely used to identify malware. However, the malware detection accuracy of existing approaches is not satisfactory since they do not consider correlation of system calls in the sequence. In this paper, we propose a new scheme called Artificial Neural Networks (ANNs) on Co-occurrence Matrices Droid (ANNCMDroid), using co-occurrence matrices to mine correlation of system calls. Our key observation is that correlation of system calls is significantly different between malware and benign software, which can be accurately expressed by co-occurrence matrices, and ANNs can effectively identify anomaly in the co-occurrence matrices. Thus at first we calculate co-occurrence matrices from the system call sequences and then convert them into vectors. Finally, these vectors are fed into ANN to detect malware. We demonstrate the effectiveness of ANNCMDroid by real experiments. Experimental results show that only 4 applications among 594 evaluated benign applications are falsely detected as malware, and only 18 applications among 614 evaluated malicious applications are not detected. As a result, ANNCMDroid achieved an F-Score of 0.981878, which is much higher than other methods.

Role of soy lecithin combined with soy isoflavone on cerebral blood flow in rats of cognitive impairment and the primary screening of its optimum combination

Li Hongrui,Wang Xianyun,Li Xiaoying,Zhou Xueyang,Wang Xuan,Li Tiantian,Xiao Rong,Xi Yuandi 한국영양학회 2023 Nutrition Research and Practice Vol.17 No.2

BACKGROUND/OBJECTIVES: Soy isoflavone (SIF) and soy lecithin (SL) have beneficial effects on many chronic diseases, including neurodegenerative diseases. Regretfully, there is little evidence to show the combined effects of these soy extractives on the impairment of cognition and abnormal cerebral blood flow (CBF). This study examined the optimal combination dose of SIF + SL to provide evidence for improving CBF and protecting cerebrovascular endothelial cells. MATERIALS/METHODS: In vivo study, SIF50 + SL40, SIF50 + SL80 and SIF50 + SL160 groups were obtained. Morris water maze, laser speckle contrast imaging (LSCI), and hematoxylineosin staining were used to detect learning and memory impairment, CBF, and damage to the cerebrovascular tissue in rat. The 8-hydroxy-2′-deoxyguanosine (8-OHdG) and the oxidized glutathione (GSSG) were detected. The anti-oxidative damage index of superoxide dismutase (SOD) and glutathione (GSH) in the serum of an animal model was also tested. In vitro study, an immortalized mouse brain endothelial cell line (bEND.3 cells) was used to confirm the cerebrovascular endothelial cell protection of SIF + SL. In this study, 50 μM of Gen were used, while the 25, 50, or 100 μM of SL for different incubation times were selected first. The intracellular levels of 8-OHdG, SOD, GSH, and GSSG were also detected in the cells. RESULTS: In vivo study, SIF + SL could increase the target crossing times significantly and shorten the total swimming distance of rats. The CBF in the rats of the SIF50 + SL40 group and SIF50 + SL160 group was enhanced. Pathological changes, such as attenuation of the endothelium in cerebral vessels were much less in the SIF50 + SL40 group and SIF50 + SL160 group. The 8-OHdG was reduced in the SIF50 + SL40 group. The GSSG showed a significant decrease in all SIF + SL pretreatment groups, but the GSH showed an opposite result. SOD was upregulated by SIF + SL pretreatment. Different combinations of Genistein (Gen)+SL, the secondary proof of health benefits found in vivo study, showed they have effective antioxidation and less side reaction on protecting cerebrovascular endothelial cell. SIF50 + SL40 in rats experiment and Gen50 + SL25 in cell test were the optimum joint doses on alleviating cognitive impairment and regulating CBF through protecting cerebrovascular tissue by its antioxidant activity. CONCLUSIONS: SIF+SL could significantly prevent cognitive defect induced by β-Amyloid through regulating CBF. This kind of effect might be attributed to its antioxidant activity on protecting cerebral vessels.

Syntheses, Structures, and Luminescence Properties of Two Copper(II) Complexes Constructed by Rigid Bis(triazole) and Nitrogen-containing Carboxylic Acid Ligands

Xiao-Xiao,Zuo-Xi Li,Bao-yi Yu,Guang-hua Cui 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.7

Two new copper(II) complexes with the formulas [Cu(btb)(pydc)(H2O)]n (1) and [Cu(btb)0.5(nph)(H2O)]n (2) have been synthesized under hydrothermal conditions by employing a rigid bis(triazole) ligand (btb = 4,4′-bis(1,2,4-triazolyl-1-yl)-biphenyl) and two carboxylic acids mixed ligands (H2pydc = pyridine-2,5-dicarboxylic acid and H2nph = 3-nitrophthalic acid). The copper atoms present different environments, with a tetragonal pyramidal geometry in 1 and octahedral configuration in 2. Complex 1 displays a dinuclear cluster, which is further packed into a 2D supramolecular layer by classical OH · · · O hydrogen bonds. Complex 2 possesses a trinodal 3,4,4-connected 3D framework with a rare sqc69 topology. In addition, thermal stability and luminescence property were investigated.

Simultaneous Blockage of Epidermal Growth Factor Receptor and Cyclooxygenase-2 in a Human Xenotransplanted Lung Cancer Model

Mu, Xiao-Yan,Dong, Xue-Li,Sun, Jie,Ni, Yu-Hua,Dong, Zhang,Li, Xi-Li,Sun, Er-Lian,Yi, Zhou,Li, Gao Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.1

The effects of erlotinib combined with celecoxib in a lung cancer xenograft model were here explored with a focus on possible mechanisms. A xenotransplanted lung cancer model was established in nude mice using the human lung cancer cell A549 cell line and animals demonstrating tumour growth were randomly divided into four groups: control, erlotinib, celecoxib and combined (erotinib and celecoxib). The tumor major axis and short diameter were measured twice a week and after 40 days tissues were collected for immunohistochemical analyses of Bcl-2 and Bax positive cells and Western-blotting analyses for the epidermal growth factor recepto (EGFR), P-EGFR, and cyclooxygenase-2 (COX-2). Tumor size in the combined group was smaller than in the others (p<0.01) and the percentage of Bcl-2 positive cells was fewer in most cases (p<0.01), while that of Bax positive cells was greater than in the erlotinib and celecoxib groups (P>0.05). Western blotting showed decreased expression of P-EGFR and COX-2 with both erlotinib and celecoxib treatments, but most pronouncedly in the combined group (P<0.05). Simultaneous blockage of the EGFR and COX-2 signal pathways exerted stronger growth effects in our human xenotransplanted lung cancer model than inhibition of either pathway alone. The anti-tumor effects were accompanied by synergetic inhibition of tumor cell apoptosis, activation of p-EGFR and expression of COX-2.