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Stability Criterion of Linear Delayed Impulsive Differential Systems with Impulse TimeWindows
Huamin Wang,Shukai Duan,Chuandong Li,Lidan Wan,Tingwen Huang 제어·로봇·시스템학회 2016 International Journal of Control, Automation, and Vol.14 No.1
In this paper, we study the uniform stability of linear delayed differential equations with impulse timewindows. By means of Lyapunov functions and Razumikhin technique combined with classification discussiontechnique, the criterion of uniform stability is obtained, which may be used to discuss others stability of delayeddifferential equations with impulse time windows. Two examples are given to illustrate the effectiveness of thetheoretic result.
Ping Li,Shiqiao Gao,Huatong Cai,Huamin Wang 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.
Through establishing the electroelastic model of hybrid piezoelectric(PE) and electromagnetic(EM) energy harvesting from randomvibrations, normalized expressions of mean amplitude, voltage, current, power and their spectral density (SD) are derived, and effectsof electromechanical coupling strength on harvester’s performances are studied by numerical calculation and experimental test. It isfound that the stronger coupling effect, the smaller amplitude and working space required, and the bigger mean voltage, current andpower output until up to their maximums. Furthermore, variation extent of mean voltage, current and power with the PE and EMload increasing varies with the coupling strength. Besides, coupling strength changes the SD distributing in frequency domain. In theweak coupling, maximal SD of voltage, current and power are at the natural frequency of harvester. However, with the coupling effectstrengthening, the frequency corresponding to peak spectral density is bigger than the natural frequency , and the 3dB bandwidth ofharvester is much larger accordingly; moreover, the bandwidth decreases with EM load increasing while it rises firstly and fall laterwith PE load increasing, which reaches the maximum at the optimal load. The analysis results can provide certain criteria for hybridpiezoelectric-electromagnetic energy harvester design.
Dongqi Jiang,Huamin Li,Shuyang Sun 한국식품과학회 2020 Food Science and Biotechnology Vol.29 No.12
The search for enzymes with histamine-degradingactivity is of great interest, since it has great potential inthe way of solving the problem of high histamine levels infood. In this study, the gene of a novel histamine-degradingenzyme, i.e., glyceraldehyde-3-phosphate dehydrogenase(GAPDH) from Lactobacillus plantarum was cloned andsuccessfully expressed in Escherichia coli DH5a, with therecombinant host determined as histamine-degradingactive. The recombinant GAPDH was then purified tohomogeneity by ammonium sulfate fraction and gel filtration. The optimum pH and temperature were 5.5 and 40 Cand it was strongly resistant to SO2 and ethanol. Afterwards,the histamine degradative activity of partiallypurified GAPDH in actual wine environments (grape andcherry wines) was examined by incubating the enzymes inthe middle, near the end and completion of malolacticfermentation, and histamine in the correspondingcontaminated wines was decreased by 36.8–52.4%,59.6–66.9% and 83.1–85.5%, respectively.
Synthesis of 5-benzoylacenaphthene in the presence of Lewis acidic ionic liquids
Min Chen,Di Li,Ying Luo,Minqiang He,Jimin Xie,Huamin Li,Xinhua Yuan 한국공업화학회 2011 Journal of Industrial and Engineering Chemistry Vol.17 No.1
Acylation of acenaphthene with benzoyl chloride to 5-benzoylacenaphthene catalyzed by various Lewis acidic ionic liquids (ILs) was investigated. Ionic liquids of different alkyl chain length and metal chloride were synthesized and tested for the reaction to discuss the effects of Lewis acidity of the ionic liquid on the synthesis of 5-benzoylacenaphthene. Pure 5-benzoylacenaphthene was obtained and its structure was identified by GC/MS, FT-IR and 1H NMR spectra. [Emim]Cl/AlCl3 ionic liquid was found to be the most active catalyst in the acylation. The yield of 5-benzoylacenaphthene was up to 87% and the regioselectivity towards 5-benzoylacenaphthene was up to 90%. The experimental resulted show that [Emim]Cl/AlCl3 can be used as both catalyst and solvent, and it is reusable and environmentally friendly for the preparation of 5-benzoylacenaphthene.
Investigation of The Magnetic Properties of Zn₂TiO₄ Single Crystal
Ying Liu,Liang Li,Huamin Yu,Tian Cui,Dapeng Xu 한국자기학회 2019 Journal of Magnetics Vol.24 No.3
The magnetic properties of Zn₂TiO₄ single crystals were investigated by physical property measurement system (PPMS). The field dependent magnetization (M-H) curves showed a weak ferromagnetism at low field and diamagnetism at high field for Zn₂TiO₄ single crystals. The zero-field-cooled (ZFC) and field-cooled (FC) curves further confirmed ferromagnetic behavior of the sample. With the temperature decreasing from 300 to 10 K, the weak ferromagnetism increased slowly. Around 50 K, the M-T curves had a shoulder. After the temperature decreased to 10 K, the ferromagnetism increased significantly. The magnetic mechanism was investigated using the first-principle calculations method. The origin of the ferromagnetic was discussed.
Alkylation of anthracene to 2-isopropylanthracene catalyzed by Lewis acid ionic liquids
Min Chen,Ying Luo,Guofang Li,Minqiang He,Jimin Xie,Huamin Li,Xinhua Yuan 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.6
Alkylation of anthracene with 2-chloropropane to 2-isopropylanthracene catalyzed by various Lewis acidic ionic liquids (ILs), such as [Emim]Cl-AlCl3, [Emim]Cl-FeCl3, [Emim]Cl-ZnCl2, [Bmim]Cl-AlCl3, and [Omim]Cl-AlCl3 ([Emim]+=1-ethyl-3-methylimidazolium cation, [Bmim]+=1-butyl-3-methylimidazolium cation, [Omim]+=1-octyl-3- methylimidazolium cation,), was investigated. [Emim]C1-A1C13 ionic liquid was found to be the most active catalyst in the alkylation. The yield of 2-isopropylanthracene was up to 74.5% and the selectivity of 2-isopropylanthracene was up to 82.9%. The [Emim]C1-A1C13 ionic liquid catalyst showed good catalytic activity after running for 6 times. Ease of product separation and the recycling performance of the ionic liquid catalyst is expected to contribute to the development of clean and environmentally friendly strategy for the synthesis of 2-isopropylanthracene.
Minqiang He,Min Chen,Aixia Pan,Jimin Xie,Huamin Li,Xinhua Yuan,Xiaonong Cheng 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.10
A novel one-pot catalytic synthesis of 1-benzoylpyrene through acylation of pyrene with benzoic anhydride catalyzed by several heteropoly acids (HPAs) was investigated. Pure 1-benzoylpyrene was obtained and its structure was identified by GC/MS, FT-IR and 1H NMR spectra. Silica-supported phosphotungstic heteropoly acid (PW/SiO2)was found to be the most active catalyst in the acylation. The yield and the selectivity of 1-benzoylpyrene were up to 62.5% and 100%, respectively. The effects of experimental parameters on the catalytic acylation reaction, and the possibility of reusability of PW/SiO2 catalyst were studied. PW/SiO2 catalyst is easily separable from the reaction mixture and reusable without loss of its activity.
Component Prototyping for the China Spallation Neutron Source Project
Jie Wei,Yanwei Chen,Yunlong Chi,Changdong Deng,Haiyi Dong,Shinian Fu,Wei He,Kaixi Huang,Wen Kang,Jian Li,Huafu Ouyang,Huamin Qu,Caitu Shi,Hong Sun,Jingyu Tang,Juzhou Tao,Sheng Wang,Zhongxiong Xu,Xueju 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.5
The China Spallation Neutron Source (CSNS) complex consists of an H- linear accelerator, a rapid cycling synchrotron accelerating the beam to 1.6 GeV, a solid tungsten target station and instruments for spallation neutron applications. The facility operates at a 25-Hz repetition rate with an initial design beam power of 120 kW and is upgradeable to 500 kW. The primary challenge is to build a robust and reliable user-friendly facility with upgrade potential at a fraction of the \world standard" cost. Success of the project relies on the results of prototyping research & development (R&D) of key technical systems and components. This paper discusses the prototyping experiences of the past two and a half years. The China Spallation Neutron Source (CSNS) complex consists of an H- linear accelerator, a rapid cycling synchrotron accelerating the beam to 1.6 GeV, a solid tungsten target station and instruments for spallation neutron applications. The facility operates at a 25-Hz repetition rate with an initial design beam power of 120 kW and is upgradeable to 500 kW. The primary challenge is to build a robust and reliable user-friendly facility with upgrade potential at a fraction of the \world standard" cost. Success of the project relies on the results of prototyping research & development (R&D) of key technical systems and components. This paper discusses the prototyping experiences of the past two and a half years.