Influences of Bridge Group on Thermal and Mechanical Properties of Epoxy Resins

Liu Yuan,Zhao Jun,Liu Ai-Qin,Liu Xiao-Qing,Luo Jun 한국고분자학회 2020 폴리머 Vol.44 No.4

In order to obtain thermosetting epoxy resin, it is the prerequisite condition that the epoxy precursor must contain at least two epoxy groups. Thus, bridge group is needed to link the epoxy groups, and naturally, the chemical structure of the bridge group may also influence the thermomechanical performances of the cured epoxy resin. However, literature about the effects of bridge group on properties of cured epoxy is seldom published. To fill the gap, three model epoxy monomers containing different bridge groups have been synthesized from 4,4"-dihydroxydiphenyl, 1,1-bis(4- hydroxyphenyl)cyclohexane and bisphenol A in this work. After chemical structure confirmation, all of the monomers are cured by methylhexahydrophthalic anhydride (HMMPA), and the properties of the obtained cured network are evaluated by differential scanning calorimetry (DSC), dynamic thermomechanical analysis (DMA), tensile test and scanning electron microscope (SEM). The results show that bulky bridge group can effectively increase the glass transition temperature, enhance the tensile strength, and enlarge elongation at break of the cured epoxy resin.

Research on data augmentation algorithm for time series based on deep learning

Shiyu Liu,Hongyan Qiao,Lianhong Yuan,Yuan Yuan,Jun Liu 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.6

Data monitoring is an important foundation of modern science. In most cases, the monitoring data is time-series data, which has high application value. The deep learning algorithm has a strong nonlinear fitting capability, which enables the recognition of time series by capturing anomalous information in time series. At present, the research of time series recognition based on deep learning is especially important for data monitoring. Deep learning algorithms require a large amount of data for training. However, abnormal sample is a small sample in time series, which means the number of abnormal time series can seriously affect the accuracy of recognition algorithm because of class imbalance. In order to increase the number of abnormal sample, a data augmentation method called GANBATS (GAN-based Bi-LSTM and Attention for Time Series) is proposed. In GANBATS, Bi-LSTM is introduced to extract the timing features and then transfer features to the generator network of GANBATS.GANBATS also modifies the discriminator network by adding an attention mechanism to achieve global attention for time series. At the end of discriminator, GANBATS is adding averagepooling layer, which merges temporal features to boost the operational efficiency. In this paper, four time series datasets and five data augmentation algorithms are used for comparison experiments. The generated data are measured by PRD(Percent Root Mean Square Difference) and DTW(Dynamic Time Warping). The experimental results show that GANBATS reduces up to 26.22 in PRD metric and 9.45 in DTW metric. In addition, this paper uses different algorithms to reconstruct the datasets and compare them by classification accuracy. The classification accuracy is improved by 6.44%-12.96% on four time series datasets.

Improved DV-Hop Localization Algorithm Based on Bat Algorithm in Wireless Sensor Networks

( Yuan Liu ),( Junjie Chen ),( Zhenfeng Xu ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.1

Obtaining accurate location information is important in practical applications of wireless sensor networks (WSNs). The distance vector hop (DV-Hop) is a frequently-used range-free localization algorithm in WSNs, but it has low localization accuracy. Moreover, despite various improvements to DV-Hop-based localization algorithms, maintaining a balance between high localization accuracy and good stability and convergence is still a challenge. To overcome these shortcomings, we proposed an improved DV-Hop localization algorithm based on the bat algorithm (IBDV-Hop) for WSNs. The IBDV-Hop algorithm incorporates optimization methods that enhance the accuracy of the average hop distance and fitness function. We also introduce a nonlinear dynamic inertial weight strategy to extend the global search scope and increase the local search accuracy. Moreover, we develop an updated solutions strategy that avoids premature convergence by the IBDV-Hop algorithm. Both theoretical analysis and simulation results show that the IBDV-Hop algorithm achieves higher localization accuracy than the original DV-Hop algorithm and other improved algorithms. The IBDV-Hop algorithm also exhibits good stability, search capability and convergence, and it requires little additional time complexity and energy consumption.

Distributed Fixed-time Optimization for Multiple Mechanical Systems

Yuan Liu,Pinxiao Liu,Bing Zhang,Xianpu Zeng 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.9

Under the general unbalanced directed communication graphs, distributed fixed-time optimization problem is studied for multiple mechanical systems modeled by Euler-Lagrange equations. Distributed controllers have been developed to achieve the optimal position of each agent within a fixed time by integrating distributed fixedtime estimator techniques and a fixed-time control design in a cohesive manner. The effectiveness of the proposed control protocol is also illustrated by a numerical simulation.

2,5-Hexanedione induces apoptosis via a mitochondriamediated pathway in PC12 cells

Yuan Qi,Shuang-yue Li,Feng-yuan Piao,Zhe-min Wang,Ruo-lin Chen,Shuang Liu,Jing-shun Shen 대한독성 유전단백체 학회 2015 Molecular & cellular toxicology Vol.11 No.1

2,5-Hexanedione (HD) is the main active metabolite of n-hexane and mediates the neurotoxicity of the parent compound. Studies suggested that apoptosis involved in HD neurotoxicity. However, the mechanism of HD-induced neuronal apoptosis remains unknown. To explore its underlying mechanism, we treated PC12 cells with 5, 10 and 20 mM HD for 24 h, respectively. We found that HD induced apoptotic death in PC12 cells in a dose-dependent manner. Moreover, HD down-regulated Bcl-2 expression, up-regulated Bax expression and Bax/Bcl-2 ratio, promoted the disruption of mitochondrial transmembrane potential, induced the release of cytochrome c from mitochondria, and increased the activity of caspase-3 in PC12 cells, which were all the key regulators of intrinsic apoptotic pathway. These results indicate that HD induces apoptosis via a mitochondria- mediated pathway in PC12 cells.

High-mass Starless Clumps in the Inner Galactic Plane: The Sample and Dust Properties

Yuan, Jinghua,Wu, Yuefang,Ellingsen, Simon P.,II, Neal J. Evans,Henkel, Christian,Wang, Ke,Liu, Hong-Li,Liu, Tie,Li, Jin-Zeng,Zavagno, Annie American Astronomical Society 2017 The Astrophysical journal Supplement series Vol.231 No.1

<P>We report a sample of 463 high-mass starless clump (HMSC) candidates within -60 degrees < l < 60 degrees and -1 degrees < b < 1 degrees. This sample has been singled out from 10,861 ATLASGAL clumps. None of these sources are associated with any known star-forming activities collected in SIMBAD and young stellar objects identified using color-based criteria. We also make sure that the HMSC candidates have neither point sources at 24 and 70 mu m. nor strong extended emission at 24 mu m. Most of the identified HMSCs are infrared dark, and some are even dark at 70 mu m. Their distribution shows crowding in Galactic spiral arms and toward the Galactic center and some wellknown star-forming complexes. Many HMSCs are associated with large-scale filaments. Some basic parameters were attained from column density and dust temperature maps constructed via fitting far-infrared and submillimeter continuum data to modified blackbodies. The HMSC candidates have sizes, masses, and densities similar to clumps associated with Class II methanol masers and H. II. regions, suggesting that they will evolve into star-forming clumps. More than 90% of the HMSC candidates have densities above some proposed thresholds for forming high-mass stars. With dust temperatures and luminosity-to-mass ratios significantly lower than that for star-forming sources, the HMSC candidates are externally heated and genuinely at very early stages of high-mass star formation. Twenty sources with equivalent radii r(eq) < 0.15 pc and mass surface densities Sigma > 0.08 g cm(-2) could be possible high-mass starless cores. Further investigations toward these HMSCs would undoubtedly shed light on comprehensively understanding the birth of high-mass stars.</P>

Expression of Codon Optimized β₂-Adrenergic Receptor in Sf9 Insect Cells for Multianalyte Detection of β-Agonist Residues in Pork

( Yuan Liu ),( Jian Wang ),( Yang Liu ),( Liting Yang ),( Xuran Zhu ),( Wei Wang ),( Jiaxiao Zhang ),( Dong Wei ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.9

β₂-adrenergic receptor (β₂-AR) was expressed efficiently using Bac-to-Bac Baculovirus Expression System in Sf9 cells as a bio-recognition element for multianalyte screening of β-agonist residues in pork. Sf9 cells were selected as the expression system, and codon optimization of wild-type nucleic acid sequence and time-dependent screening of expression conditions were then carried out for enhancing expression level and biological activity. Under optimum conditions of multiplicity of infection (MOI) = 5 and 48 h post transfection, the protein yield was up to 1.23 mg/ml. After purification by chromatographic techniques, the purified recombinant protein was applied to develop a direct competitive enzyme-linked receptor assay (ELRA) and the efficiency and reliability of the assay was determined. The IC50 values of clenbuterol, salbutamol, and ractopamine were 28.36, 50.70, and 59.57 μg/l, and clenbuterol showed 47.61% and 55.94% cross-reactivities with ractopamine and salbutamol, respectively. The limit of detection (LOD) was 3.2 μg/l and the relevant recoveries in pork samples were in the range of 73.0-91.2%, 69.4-84.6%, and 63.7-80.2%, respectively. The results showed that it had better performance compared with other present nonradioactive receptor-based assays, indicating that the genetically modified β₂-AR would have great application potential in detection of β-agonist residues.

Numerical Simulations of Pull-In Voltage in Wave-Bar NEMS Switches for Nonvolatile Memory Application

Yuan Liu,WenFeng Xiang,JiaQi Zhang,MingHao Hu,Kun Zhao,ShouXian Zhong 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.8

A heterogeneous lattice structure modeling technique supported by multiquadric radial basis function networks

Liu Yuan,Yang Huiyuan,Zhao Yaoyao Fiona,Zheng Guolei 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.1

With the rapid advancement of the multimaterial additive manufacturing (AM) technology, the heterogeneous lattice structures (HLSs) comprising the multiphase materials with gradual variations have become feasible and accessible to the industry. However, the multimaterial AM capabilities have far outpaced the modeling capability of design systems to model and thus design novel HLSs. To further expand the design space for the utilization of AM technology, this paper proposes a method for modeling HLS with complex geometries and smooth material transitions. The geometric modeling and material modeling problems are formulated in a rigorous and computationally effective manner. The geometric complexity of HLS is significantly reduced by a semi-analytical unit cell decomposition strategy that is applied to split HLS into material units: struts and connectors. The smooth material transitions of the connector associated with multimaterial struts are realized by interpolating the discrete material property values defined at control points using a multiquadric radial basis function network.

Crystal structure of citric acid-acetonitrile (1/1), C₈H₁₁NO₇

Liu, Yang,Zheng, Xiao-Yuan,Qin, Liu-Lei,Zhu, Chun-Li,Liu, Zunqi De Gruyter 2019 Zeitschrift für Kristallographie. New crystal Vol.234 No.2

<P><B>Abstract</B></P><P>C<SUB>8</SUB>H<SUB>11</SUB>NO<SUB>7</SUB>, triclinic,<I>P</I>1̄ (no. 2),<I>a</I>= 5.5944(13) Å,<I>b</I>= 10.402(3) Å,<I>c</I>= 10.666(3) Å,<I>α</I>= 110.297(2)<SUP><I>o</I></SUP>,<I>β</I>= 101.342(3)<SUP><I>o</I></SUP>,<I>γ</I>= 104.701(2)<SUP><I>o</I></SUP>,<I>V</I>= 534.6(2) Å<SUP>3</SUP>,<I>Z</I>= 2,<I>R</I><SUB>gt</SUB>(<I>F</I>) = 0.0318,<I>wR</I><SUB>ref</SUB>(<I>F</I><SUP>2</SUP>) = 0.0833,<I>T</I>= 293(2) K.</P>