H<SUB>∞</SUB> finite-time stability for discrete-time singular linear time-varying systems

Qian Ma,Yuangong Sun 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10

This paper deals with H∞ finite-time stability for a class of discrete-time singular linear time-varying systems. Sufficient conditions have been established such that the system is regular, causal and H∞ finite-time stable, which are expressed in linear matrix inequalities and can be determined by using LMI Control Toolbox in Matlab. Finally, a numerical example is given to illustrate the effectiveness of the result.

Transcriptome profiling and identification of functional genes involved in H2S response in grapevine tissue cultured plantlets

Qian Ma,Jingli Yang 한국유전학회 2018 Genes & Genomics Vol.40 No.12

Hydrogen sulfide ( H2S), a small bioactive gas, has been proved functioning in plant growth and development as well as alleviation of abiotic stresses, which including promoting seed germination, accelerating embryonic root growth, regulating flower senescence, inducing stomatal closure, and defending drought, heat, heavy metals and osmotic stresses etc. However, the molecular functioning mechanism of H2S was still unclear. The primary objective of this research was to analyze the transcriptional differences and functional genes involved in the H2S responses. In details, 4-week-old plantlets in tissue culture of grapevine (Vitis vinifera L.) cultivar ‘Zuoyouhong’ were sprayed with 0.1 mM NaHS for 12 h, and then transcriptome sequencing and qRT-PCR analysis were used to study the transcriptional differences and functional genes involved in the H2S responses. Our results indicated that 650 genes were differentially expressed after H2S treatment, in which 224 genes were up-regulated and 426 genes were down-regulated. The GO enrichment analysis and KEGG enrichment analysis results indicated that the up-regulated genes after H2S treatment focused on carbon metabolism, biosynthesis of amino acids, and glycolysis/gluconeogenesis, and the down-regulated genes were mainly in metabolic pathways, biosynthesis of secondary metabolites, and plant hormone signal transduction. Analyzing the transcription factor coding genes in details, it was indicated that 10 AP2/EREBPs, 5 NACs, 3 WRKYs, 3 MYBs, and 2 bHLHs etc. transcription factor coding genes were up-regulated, while 4 MYBs, 3 OFPs, 3 bHLHs, 2 AP2/EREBPs, 2 HBs etc. transcription factor coding genes were down-regulated. Taken together, H2S increased the productions in secondary metabolites and a variety of defensive compounds to improve plant development and abiotic resistance, and extend fruits postharvest shelf life by regulating the expression of AP2/EREBPs, WRKYs, MYBs, CABs, GRIP22, FERRITINs, TPSs, UGTs, and GHs etc.

New Explicit Criteria for Finite-time Stability of Singular Linear Systems Using Time-dependent Lyapunov Functions

Qian Ma,Yuangong Sun 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.4

In this paper, the finite time stability and H∞ finite-time stability of singular linear systems are considered. By constructing a class of time-dependent Lyapunov functions and introducing a zero term with free weighting matrices, we first establish a new explicit criterion in the form of LMIs for finite-time stability of the system. Then, an H∞ finite-time stability criterion for the system is obtained. The given results are easily verifiable and less conservative compared with some existing ones in the literature. Finally, four numerical examples are given to demonstrate the effectiveness of the proposed method.

Facile synthesis of flower-like α-Fe2O3/ZnFe2O4 architectures with self-assembled core-shell nanorods for superior TEA detection

Ma Qian,Li Hui,Liu Yu,Liu Mingle,Fu Xinghua,Chu Shushu,Li Hang,Guo Jia 한국물리학회 2021 Current Applied Physics Vol.21 No.-

Uniform flower-like α-Fe2O3 architectures with self-assembled core-shell nanorods are constructed and successfully prepared via the facile process. The concentration of Fe salt plays a great significance for morphological evolution from nanorods to self-assembled microflowers. Flower-like α-Fe2O3/ZnFe2O4 consisting of α-Fe2O3 core and ZnFe2O4 shell nanorods are derived from FeOOH/ZIF-8 precursors. The detailed studies reveal that the tunable growth of ZIF-8 nanoparticles on three-dimensional FeOOH microflowers at room temperature and the availble calcination regulation are responsible for the formation of core-shell Fe2O3/ZnFe2O4 composites. The highest response value of flower-like α-Fe2O3/ZnFe2O4 architectures to 100 ppm triethylamine (TEA) has been improved to 141 at 280 ◦C, which is calculated to be 6.2 times compared with flower-like α-Fe2O3 architectures (22.7). The enhanced gas-sensing mechanism of α-Fe2O3/ZnFe2O4 composites can be attributed to the typical microflowers structures, the large specific surface area, the effective heterojunctions between α-Fe2O3 core and ZnFe2O4 shell, and the improved electron transfer process.

ASESDP : An Efficient Service Discovery Protocol in Pervasive Computing Environments

Ma, Qianli,Liao, Minghong,Jiang, Shouxu,Hong, Wan-Pyo,Gao, Zhenguo The Korea Institute of Information and Commucation 2008 Journal of information and communication convergen Vol.6 No.4

Service discovery is the technology of finding needed services in networks, and a key point in pervasive computing environments. This paper presents a novel service discovery protocol: ASESDP(AIP and SRR Enhanced Service Discovery Protocol). In ASESDP, tow schemes are proposed to enhance its performance: AIP(Advertisement Information Piggybacked) and SRR(Shortest Reply Route). In AIP, parts of advertisement information are piggybacked in the service reply packet, which makes the advertisement information propagating along the reply path, and spreads its transmission area. In SRR, in order to reduce the service response time, the shortest reply route is chosen to forward the service reply packet to the source node sending the service request. With the theoretical analysis and Glomosim simulation results, it is verified that ASESDP can reduce the number of service request packets, save the response time, and improve the efficiency of service discovery.

Comparative Genomic and Genetic Functional Analysis of Industrial L-Leucine- and L-Valine-Producing Corynebacterium glutamicum Strains

( Yuechao Ma ),( Qixin Chen ),( Yi Cui ),( Lihong Du ),( Tuo Shi ),( Qingyang Xu ),( Qian Ma ),( Xixian Xie ),( Ning Chen ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.11

Corynebacterium glutamicum is an excellent platform for the production of amino acids, and is widely used in the fermentation industry. Most industrial strains are traditionally obtained by repeated processes of random mutation and selection, but the genotype of these strains is often unclear owing to the absence of genomic information. As such, it is difficult to improve the growth and amino acid production of these strains via metabolic engineering. In this study, we generated a complete genome map of an industrial L-valine-producing strain, C. glutamicum XV. In order to establish the relationship between genotypes and physiological characteristics, a comparative genomic analysis was performed to explore the core genome, structural variations, and gene mutations referring to an industrial L-leucine-producing strain, C. glutamicum CP, and the widely used C. glutamicum ATCC 13032. The results indicate that a 36,349 bp repeat sequence in the CP genome contained an additional copy each of lrp and brnFE genes, which benefited the export of L-leucine. However, in XV, the kgd and panB genes were disrupted by nucleotide insertion, which increase the availability of precursors to synthesize L-valine. Moreover, the specific amino acid substitutions in key enzymes increased their activities. Additionally, a novel strategy is proposed to remodel central carbon metabolism and reduce pyruvate consumption without having a negative impact on cell growth by introducing the CP-derived mutant H+/citrate symporter. These results further our understanding regarding the metabolic networks in these strains and help to elucidate the influence of different genotypes on these processes.

Efficient Expression of Glucagon-like Peptide-1 Analogue with Human Serum Albumin Fusion Protein in Pichia pastoris Using the Glyceraldehyde-3-phosphate Dehydrogenase Promoter

Kai Qian,XiaoHai Gong,Bo Guan,SuPing Wu,JingJing Zhang,Jing Qian,YanFei Cai,Yun Chen,ZuoYing Duan,Xin Ma,HuaZhong Li,Jian Jin 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.4

Glucagon-like peptide-1 (GLP-1) was a potential therapeutic drug for type II diabetes, mainly because of the stimulatory effect on insulin secretion under condition of high blood glucose. We used PCR to obtain a recombination gene, GGH, in which two GLP-1 (GLP-1A2G) mutants were connected in series and then fused to the N terminal of human serum albumin. The fusion gene was inserted into pGAPZaA plasmid with Saccharomyces cerevisiae α- factor secretion signal sequence, and was expressed by the glyceraldehyde-3-phosphate dehydrogenase (GAP) promoter. The engineered strain was constructed by integrating the recombinant plasmid pGAPZαA/GGH into the genome of Pichia pastoris GS115. Genome PCR and western blot showed that the recombinant P. pastoris successfully expressed the fusion protein GGH. The yield of GGH reached 78 mg/L after 72 h fermentation in a flask, using glucose as the optimal carbon source. Fed-batch fermentation was investigated in a 5 L bioreactor, and the expression level of GGH reached 246 mg/L in 52 h. The fusion protein GGH was purified in four steps, and the final purity was 96.1%. The in vitro bioactivity of GGH was the same as that expressed in P. pastoris by the AOX1 promoter. This study described an efficient way to express GGH fusion protein in P. pastoris using GAP promoter, fermentation was easier to control without carbon source change and fermentation time was 20 h less than AOX1 promotercontrolled GGH fermentation.

Two-Dimensional SPH Analysis of Seepage with Water Injection Process for Different Crack Morphologies

Haichun Ma,Jingping Wang,Jiazhong Qian,Xiaohui Tan,Luwang Chen,Yaping Deng,Zhitang Lu,Lei Ma 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.5

Crack seepage in nature involves natural and water injection flow, causing crack morphology in nature to be varied. Using the numerical simulation method of smoothed particle hydrodynamics (SPH), the natural free flow process in a crack was analyzed. With the interference of the initial velocity of the x = 0 particles, the other terminal particles were shifted, and the particles with initial velocities were reversed. For water injection simulations, ghost particles were set to block particles from overflowing, as particles subjected to injection water were mobilized more quickly than under free flow conditions. For rough cracks, particle magnitude was affected by the boundary shape, but overall particle velocity was influenced little, and the distribution of particles was sparse and densely spaced. For the branch crack simulation, overall particle seepage velocity decreased, but particles moved faster through the wider branch than through the narrower branch. SPH can simulate the seepage through crack networks and be used to analyze the effects of different crack geometries and physical properties.

The effect of HCP on the formation of twin boundaries and dislocations in Ni–Co alloys

Ma Rui-bo,Zhou Li-li,Liang Yong-chao,Chen Qian,Tian Ze-an,Liu Rang-su,Mo Yun-fei,Gao Ting-hong,Xie Quan 한국물리학회 2021 Current Applied Physics Vol.29 No.-

In this study, molecular dynamics (MD) was used to simulate the rapid solidification process of Ni47Co53 and Ni48Co52 alloys at a cooling rate of 1012 K/s. The effects of HCP on the formation of twin boundaries and dislocations in two Ni–Co alloys are studied. It is found that the difference of HCP clusters is the main effect that producing discrepancies on microstructure of two alloys. The number of HCP clusters accounted for 9.23% in Ni47Co53 alloy. They are regularly arranged to form the number of single-layer twin boundaries, and each twin boundary ends in a dislocation. The FCC and HCP structures coexist in the same atomic layers, which is easy to create dislocations. The relatively standard FCC crystal and only 0.32% HCP clusters are formed in Ni48Co52 alloy at 300 K. That small amount of HCP clusters are dispersed on the surface, and cause the formation of dislocation in the border with FCC clusters.

Secondary Voltage Control for Reactive Power Sharing in an Islanded Microgrid

Qian Guo,Hongyan Wu,Liaoyuan Lin,Zhihong Bai,Hao Ma 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.1

Owing to mismatched feeder impedances in an islanded microgrid, the conventional droop control method typically results in errors in reactive power sharing among distributed generation (DG) units. In this study, an improved droop control strategy based on secondary voltage control is proposed to enhance the reactive power sharing accuracy in an islanded microgrid. In a DG local controller, an integral term is introduced into the voltage droop function, in which the voltage compensation signal from the secondary voltage control is utilized as the common reactive power reference for each DG unit. Therefore, accurate reactive power sharing can be realized without any power information exchange among DG units or between DG units and the central controller. Meanwhile, the voltage deviation in the microgrid common bus is removed. Communication in the proposed strategy is simple to implement because the information of the voltage compensation signal is broadcasted from the central controller to each DG unit. The reactive power sharing accuracy is also not sensitive to time-delay mismatch in the communication channels. Simulation and experimental results are provided to validate the effectiveness of the proposed method.