Frequency Slice Wavelet Transform for Dynamic Signal Analysis

Zhongwei Jiang,Zhonghong Yan 대한전기학회 2010 정보 및 제어 심포지엄 논문집 Vol.2010 No.10

A new time-frequency analysis method, called frequency slice wavelet transform (FSWT), is introduced. The basic idea of FSWT comes from the short-time Fourier transform(STFT) by extension directly to frequency domain. The original signal can be decomposed by frequency slice function(FSF), which is similar to the wavelet base. Also the signal can be reconstructed by the FSWT representation in an easy way without the strict limitation in wavelet theory. In this paper, the basic theory of FSWT are described first. Tow application examples are demonstrated the efficiency of FSWT on structure dynamic analysis. First example shows how to identify or separate a complex impulse vibration signal. As the second example, FSWT is used to estimate the group velocity of A? Lamb wave in beam and to detect the reflection wave from a weak crack. The experimental result shows the accurate estimation of the arrival time of reflection wave from the crack and the group velocity with the aid of FSWT.

Low-temperature and solvent-free production of biomass-derived diesel-range C17 precursor via one-pot cascade acylation–alkylation over Sn4+-montmorillonite

Zhongwei Wang,Hu Li,Wenfeng Zhao,Song Yang 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.66 No.-

A novel carbon-increasing catalytic route via one-pot cascade acylation–alkylation of biomass-derived 2-methylfuran and acetic anhydride over Sn4+-exchanged K-10 montmorillonite (Sn4+-K-10) was demonstrated to be highly efficient for the production of C17 oxygenate 1,1,1-tris(5-methyl-2-furyl)ethane with a high yield of 87% and 90% selectivity at 60 °C in 8 h under solvent-free conditions. Characterization techniques manifested Sn4+-K-10 to have layered and mesoporous (5.7 nm) texture structure, Lewis–Brønsted acid paired sites and uniformly dispersed Sn species, which greatly contributed to the predominant reactivity and recyclability of Sn4+-K-10. Systematic studies based on GC–MS and NMR were also conducted to elucidate the catalytic mechanism.

Effect of Ionic Liquids on the Fibril-Formation and Gel Properties of Grass Carp (Ctenopharyngodon idellus) Skin Collagen

Zhongwei Zhai,Haibo Wang,Benmei Wei,Peiwen Yu,Chengzhi Xu,Lang He,Juntao Zhang,Yuling Xu 한국고분자학회 2018 Macromolecular Research Vol.26 No.7

Self-assembled environment of collagen is one of the important factors for improving and regulating the properties of collagen-based biomaterials. This study aimed to investigate the effect of ionic liquids (ILs) on the fibril-formation and gel properties of grass carp (Ctenopharyngodon idellus) skin collagen. Fibrillogenic kinetics analysis showed that the collagen self-assembly can be suppressed by the introduction of ILs, and the inhibitory effect is influenced by concentration and types of ILs. Scanning electron microscopy test indicated that the assembled collagen fibrils in the presence of ILs had bigger diameters than that in the conventional buffer. Differential scanning calorimetry analysis revealed that the thermal stability of collagen fibrils can be significantly increased when self-assembly is performed in the presence of ILs. Moreover, the introduction of ILs enhanced the mechanical strength of collagen gels. Finding from this work provides a new idea for improving the performance of fish-sourced collagen biomaterials.

miR-139-5p promotes neovascularization in diabetic retinopathy by regulating the phosphatase and tensin homolog

Zhongwei Zhang,Caiping Song,Tao Wang,Lei Sun,Ling Qin,Jianghua Ju 대한약학회 2021 Archives of Pharmacal Research Vol.44 No.2

Pathological retinal neovascularization is adriver of the progression of diabetic retinopathy (DR). Thepresent study sought to identify the microRNAs (miRNAs)that are diff erentially expressed during the progression ofDR as well as to explore the specifi c regulatory mechanismof those miRNAs in retinal neovascularization. Using amicroarray data set and a diabetic mouse model, it was determinedthat miR-139-5p was signifi cantly upregulated duringthe progression of DR. The in vitro investigation revealedan elevation in the miR-139-5p level in both the high glucose(HG)-treated mouse retinal microvascular endothelialcells (mRMECs) and the HG-treated human RMECs(hRMECs). The miR-139-5p overexpression elevated cellmigration, facilitated tube formation, and increased vascularendothelial growth factor (VEGF) protein level in thehRMECs. While the angiogenic eff ect of miR-139-5p overexpressionwas halted by an anti-VEGF antibody. Meanwhile,the miR-139-5p knockdown eliminated the VEGFinducedcell migration and tube formation in the hRMECs. The phosphatase and tensin homolog (PTEN) was the targetgene of the miR-139-5p. PTEN overexpression removed theangiogenic eff ect of miR-139-5p overexpression, which ledto reduced cell migration and tube formation. In the diabeticmice, the miR-139-5p antagomir eff ectively decreased theacellular capillaries and suppressed the formation of aberrantblood vessels in the retinal tissues. Taken together, miR-139-5p promotes retinal neovascularization by repressingPTEN expression.

Cloning and Expression Analysis of a Chitinase Gene Crchi1 from the Mycoparasitic Fungus Clonostachys rosea (syn. Gliocladium roseum)

Zhongwei Gan,Jinkui Yang,Nan Tao,Zefen Yu,Ke-Qin Zhang 한국미생물학회 2007 The journal of microbiology Vol.45 No.5

Clonostachys rosea (syn. Gliocladium roseum) is a well-known biocontrol agent and widely distributed around the world. In this study, an endochitinase gene Crchi1 was isolated from the mycoparasitic fungus C. rosea using the DNA walking strategy. The Crchi1 ORF is 1,746 bp long and interrupted by three introns. The cloned gene Crchi1 encodes 426 amino acid residues and shares a high degree of similarity with other chitinases from entomopathogenic and mycoparasitic fungi. Several putative binding sites for transcriptional regulation of Crchi1 in response to carbon (5'-SYGGRG-3') and nitrogen (5'-GATA-3') were identified in the upstream of Crchi1. Expression of Crchi1 gene in different carbon sources was analyzed using real-time PCR (RT-PCR). We found that the Crchi1 expression was suppressed by glucose but strongly stimulated by chitin or solubilized components of the cell wall from Rhizoctonia solani. Phylogenetic analysis of chitinases from entomopathogenic and mycoparasitic fungi suggests that these chitinases have probably evolved from a common ancestor.

A Novel Numerical Method for Considering Friction During Pre-stressing Construction of Cable-Supported Structures

Zhongwei Zhao,Bing Liang,Renzhang Yan 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.5

Suspen-dome structures are extensively used due to their superiority over traditional structures. The friction between cable and joints may severely infl uence the distribution of cable force, especially during the pre-stressing construction period. An accurate and effi cient numerical method has not yet been developed that can be used for estimating the infl uence of friction on cable force distribution. Thus, this study proposes an effi cient friction element to simulate friction between cable and joint. A fl owchart for estimating the value of friction force is introduced. These novel numerical methods were adopted to estimate the infl uence of friction on cable force distribution. The accuracy and effi ciency of these numerical methods were validated through numerical tests.

Three-dimensional fuzzy influence analysis of fitting algorithms on integrated chip topographic modeling

Zhongwei Liang,Bangyan Ye,Yijun Wang,Richard Kars Brauwer 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.10

In inspecting the detailed performance results of surface precision modeling in different external parameter conditions, the integrated chip surfaces should be evaluated and assessed during topographic spatial modeling processes. The application of surface-fitting algorithms exerts a considerable influence on topographic mathematical features. The influence mechanisms caused by different surfacefitting algorithms on the integrated chip surface facilitate the quantitative analysis of different external parameter conditions. By extracting the coordinate information from the selected physical control points and using a set of precise spatial coordinate measuring apparatus,several typical surface-fitting algorithms are used for constructing micro-topographic models with the obtained point cloud. In computing for the newly proposed mathematical features on surface models, we construct the fuzzy evaluating data sequence and present a new three-dimensional fuzzy quantitative evaluating method. Through this method, the value variation tendencies of topographic features can be clearly quantified. The fuzzy influence discipline among different surface-fitting algorithms, topography spatial features, and the external science parameter conditions can be analyzed quantitatively and in detail. In addition, quantitative analysis can provide final conclusions on the inherent influence mechanism and internal mathematical relation in the performance results of different surface-fitting algorithms, topographic spatial features, and their scientific parameter conditions in the case of surface micro modeling. The performance inspection of surface precision modeling will be facilitated and optimized as a new research idea for micro-surface reconstruction that will be monitored in a modeling process.

Investigations on Influence of Erection Process on Buckling of Large Span Structures by a Novel Numerical Method

Zhongwei Zhao,Zhi-Hua Chen,Hongbo Liu,Bingzhen Zhao 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.3

The erection process of long-span spatial structures is significantly nonlinear which is often accompanied by variations in boundary condition and material property. Many researchers have conducted investigations on construction simulation of complex structures. But few investigate influence of erection process on buckling behavior of structures in service. A method for estimating the influence was proposed. The reliability and accuracy of this method was validated. Then three kinds of structures were analyzed to estimate influence of erection process. The results indicate that some kinds of structures are sensitive to erection process. Influence of erection process on buckling capacity should be considered appropriately.

Requirements and Applications for Medical and Health Care with ICT

Zhongwei Jiang 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.6-2

Power conditioning system of Flywheel Energy Storage

Zhongwei Chen,Xudong Zou,Shanxu Duan,Huarong Wei 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

In a Flywheel Energy Storage system (FESS), the power conditioning system is the key component of controlling power transfer between the Flywheel and the power system. The dynamics of the power conditioning system directly affect the effect of FESS in dynamic regulation of power system. In this paper, power conditioning system which is made up of a doubly-fed induction machine (DFIM) connected with flywheel, a back-to-back converter for AC excitation and an excitation vector control system is studied. The excitation control strategy is presented for FESS DFIM to improve transient stability and increase transfer capability of power systems. The proposed control method has good dynamics that can respond to the system power demand quickly and accurately. Moreover, the proposed control method has good robust characteristic and applicability to improve the performance of power conditioning system. Simulation and experiment results are performed to evaluate the performance of the proposed control method.