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Chinese Chemical Letters 2014年第12期25卷 1550-1554页

作者： meng-juan liab Yan-Hong Huangb An-Qi Jub Tian-Shi Yub Ming-Qiao Geab Key Laboratory of Eco-Textiles(Jiangnan University) Ministry of Education College of Textile  Clothing Jiangnan University

This work aimed at effectively utilizing the chemically depolymerized waste poly（ethylene terephthalate）（PET） fibers into useful products for the textile *** fibers were glycolytically degraded by excess ethylene glycol as depolymerizing agent and zinc acetate dihydrate as *** glycolysis product,bis（2-hydroxyethyl） terephthalate（BHET）,was purified through repeated crystallization to get an average yield above 80%.Then,BHET was nitrated,reduced,and azotized to get diazonium ***,the produced diazonium salt was coupled with 1-（4-sulfophenyl）-3-methyl-5-pyrazolone to get azo *** structures of BHET and azo dyestuff were identified by FT1 R and ^1H NMR spectra and elemental *** filaments dyed by the synthesized azo dyestuff with the dye bath pH from 4.14 to 5.88 showed bright yellow *** performances of the dyestuff were described with dye uptake,color fastness,K/S,L^＊,a^＊,b^＊.and △E^＊ values.

关键词： Waste PET fibers Depolymerization Bis(2-hydroxyethyl) terephthalate Azo dyestuff

Precise drag prediction of airfoil flows by a new algebraic model

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Acta Mechanica Sinica 2020年第1期36卷 35-43页

作者： meng-juan Xiao Zhen-Su She State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking UniversityBeijing100871China

We report the results of accurate prediction of lift(C L)and drag(C D)coefficients of two typical airfoil flows(NACA0012 and RAE2822)by a new algebraic turbulence model,in which the eddy viscosity is specified by a stress length(SL)function predicted by structural ensemble dynamics(SED)*** accuracy of the prediction of C D with error of a few counts(one count is 10−4)and of C L with error under 1%-2%are uniformly obtained for varying angles of attack(AoA),indicating an order of magnitude improvement of drag prediction accuracy compared to currently used models(typically around 20 to 30 counts).More interestingly,the SED-SL model is distinguished with fewer parameters of clear physical meaning,which quantify underlying turbulent boundary layer(TBL)with a universal multi-layer structure,and is thus promising to be more easily generalizable to complex *** use of the new model for the calibration of flow condition in experiment and the extraction of flow physics from numerical simulation data of aeronautic flows are discussed.

关键词： Lift and drag coefficients Airfoil Flows Stress Length Structural ensemble dynamics

Symmetry-based description of laminar-turbulent transition

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Science China(Physics,Mechanics & Astronomy) 2019年第9期62卷 79-85页

作者： meng-juan Xiao Zhen-Su She Department of Mechanics and Engineering Science and State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking University

We report a simple but accurate description of flat plate transitional flow based on a structural ensemble dynamics(SED) theory of wall turbulence. It is postulated and verified by simulation data that a multi-layer stress length(SL) function ?12 presents a two-state structure in the streamwise x direction, characterizing the laminar-turbulent transition. The resulting algebraic model(called SED-SL) predicts correctly for the first time the entire streamwise profiles of the friction coefficient, Cf(x), of all seven sets of experimental(of e.g. T3 series) and simulations data of flat plate transitional flows, with varying incoming turbulence intensities Tu(or scales), superior to other closure models, with a two-state correlation for transition location Rex*= 3.3 × 10^6(1 +(Tu/0.65)^4)^-1.5/4. The extension to accurate description of transitional flows of engineering interests is discussed.

关键词： SED theory stress length multi-layer

Attractor for the Extensible Beam Equation with Nonlocal Weak Damping on Time–Dependent Space

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Acta Mathematica Sinica,English Series 2024年第4期40卷 1115-1126页

作者： Chun Xiang ZHAO Feng juan meng Institute of Applied System Analysis Jiangsu UniversityZhenjiang 212013P.R.China School of Mathematics and Physics Jiangsu University of TechnologyChangzhou 213001P.R.China

In this article,we consider the long-time behavior of extensible beams with nonlocal weak damping:ε(t)u_(tt)+Δ^(2)u-m(‖▽u‖^(2))Δu+‖u_(t)‖^(p_(u_(t)))+f(u)=h,whereε(t)is a decreasing function vanishing at *** the theory of process on time-dependent spaces,we investigate the existence of the time-dependent attractor by using the Condition(C_(t))method and more detailed *** results obtained essentially improve and complete some previous works.

关键词： Time-dependent attractor extensible beams equation nonlocal weak damping

Geophysical characteristics of anthracites with various structures: a case study on the southern Qinshui Basin, north China

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Frontiers of Earth Science 2022年第3期16卷 696-710页

作者： juan TENG Zhigang WEN Chen LI Lingye meng Hubei Key Laboratory of Petroleum Geochemistry and Environment Yangtze UniversityWuhan 430100China College of Resources and Environment Yangtze UniversityWuhan 430100China Research Institute Company Limited CNOOCBeijing 100028China Institute of Petroleum Exploration and Development of PetroChina Tarim Oilfield Korla 841000China

Deformation of coals under tectonic movements could cause reduction of mechanical strength and enhancement of gas adsorption,which might result in coal and gas outburst,and cause safety and environmental *** this study,geophysical characteristics of coals with various structures were investigated with a special emphasis on characterization of pore size distribution,rock mechanical strength,acoustic emission,resistivity and acoustic velocity of anthracites with three types of structures in the Qinshui Basin,north *** studied No.3 coal seam developed three types of structures,namely undeformed coal,cataclastic coal,and granular *** observations under scanning electron microscope and pore size distribution using N2 and CO_(2) adsorption of anthracites of three types show that the undeformed coal consists of primary micropores,and cataclastic coal is mainly composed of mesopores and well-connected *** comparison,granular coal has the least *** mechanical strength,acoustic emission,resistivity and acoustic velocity of coals with three structure types were investigated under uniaxial and triaxial *** increasing degree of deformation of anthracites,compression strength,Young’s modulus,density,acoustic emission counting and acoustic velocity decreases,while resistivity *** suggest that the evolution of pore size distribution of anthracites with increasing degree of deformation contributed to variations of geophysical characteristics of coals with different structures to some extent.

关键词： geophysical characteristics coal structures pore size distribution acoustic emission electrical resistivity acoustic velocity

0.22 THz Waveguide Bandpass Filter with High Stop-Band Suppression

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Journal of Electronic Science and Technology 2017年第3期15卷 263-266页

作者： meng-juan Zhao Yong Zhang Shuang Liu Fundamental Science on Extremely High Frequency (EHF) Laboratory University of Electronic Science and Technology of China Chengdu 611731

A terahertz（THz） waveguide band-pass filter using an iris inductive window coupled structure was designed and *** filter was designed at0.22 THz with a pass band of 20 *** measured results show that the center frequency is 0.218 THz with a pass band of 0.205 THz to 0.231 THz,the minimum insertion loss is 1.26 d B at 0.224 THz,and the return loss is less than 13.1 d *** stop-band suppression is65.6 d B at 0.193 THz and 51.8 d B at 0.243 THz,respectively,which means a good performance of high stop-band suppression.A good agreement exists between the measured S-parameters and the simulated ones,especially in the upper *** proposed THz waveguide filter has potential applications in THz communications.

关键词： Index Terms--High stop-band suppression,terahertz waveguide band-pass filter

Quasi-classical trajectory approach to the stereo-dynamics of the reaction F+HO→HF+O

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Science China Chemistry 2010年第4期53卷 927-932页

作者： juan Zhao Yan Xu Xian Zhao QingTian meng College of Physics and Electronics Shandong Normal University Jinan China State Key Laboratory of Crystal Materials Shandong University Jinan China

Quasi-classical trajectory (QCT) calculations are employed for the reaction F + HO(0,0)→HF + O based on the adiabatic potential energy surface (PES) of the ground 3A″triplet state. The average rotational alignment factor as a function of collision energy and the four polarization dependent generalized differential cross sections have been calculated in the center-of-mass (CM) frame, separately. The distribution P(θr) of the angle between k and j′, the distribution P(θr) of dihedral angle denoting k-k′-j′ correlation, and the angular distribution P(θr, Φr) of product rotational vectors in the form of polar plots are calculated as well. The effect of Heavy-Light-Heavy (HLH) mass combination and atom F’s relatively strong absorbability to charges on the alignment and the orientation of product molecule HF rotational angular momentum vectors j′ is revealed.

关键词： product polarization F + HO reaction quasi-classical trajectory vector correlations

Effects of triclosan on gonadal differentiation and development in the frog Pelophylax nigromaculatus

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Journal of Environmental Sciences 2018年第2期30卷 157-165页

作者： juan Chen Tan meng Yuanyuan Li Kun Gao Zhanfen Qin State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China University of Chinese Academy of Sciences Beijing 100049 China

Previous studies have reported that triclosan（TCS） could possess an androgenic *** aimed to investigate the effects of TCS on gonadal differentiation and development in the frog Pelophylax nigromaculatus, a sensitive amphibian species to androgenic chemicals.P. nigromaculatus tadpoles at stage 24 were exposed to TCS（3, 30, and 300 nmol/L） to stage46 in a semi-static exposure system. At the end of exposure, gonadal morphology and histology, sex ratio and gonadal expression of sex-biased genes were examined in P. nigromaculatus. In each TCS treatment group, we found several individuals whose gonads exhibited morphological and/or histological abnormalities. Gonadal histological abnormalities were characterized by few oocytes and many somatic cells. Although the percentage of the individuals with abnormal gonads was low（7.8%） among all animals treated with TCS,statistical test revealed the sex ratios in the 3 and 300 nmol/L TCS treatment groups were significantly different from the solvent control. In the 30 nmol/L TCS treatment group,abnormal gonads were also observed, although the sex ratio was not changed compared with the solvent control, which was possibly due to the smaller sample size in this group. In all the TCS treatment groups, the sex ratios were not obviously male-biased, but the expression levels of some sex-biased genes were significantly altered by TCS. Altogether,our results suggest that TCS, even at environmentally relevant concentrations, could disrupt gonadal differentiation and development in P. nigromaculatus, but we are not sure whether the disrupting effects were associated with masculinization or feminization.

关键词： Triclosan Pelophylax nigromaculatus Gonadal abnormality Androgenic activity

Visual inspection of aircraft skin:Automated pixel-level defect detection by instance segmentation

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Chinese Journal of Aeronautics 2022年第10期35卷 254-264页

作者： meng DING Boer WU juan XU Abdul Nasser KASULE Hongfu ZUO College of Civil Aviation Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Civil Aircraft Health Monitoring and Intelligent Maintenance of CAAC Nanjing 210016China

Skin defect inspection is one of the most significant tasks in the conventional process of aircraft *** paper proposes a vision-based method of pixel-level defect detection,which is based on the Mask Scoring ***,an attention mechanism and a feature fusion module are introduced,to improve feature ***,a new classifier head—consisting of four convolutional layers and a fully connected layer—is proposed,to reduce the influence of information around the area of the ***,to evaluate the proposed method,a dataset of aircraft skin defects was constructed,containing 276 images with a resolution of 960×720 *** results show that the proposed classifier head improves the detection and segmentation accuracy,for aircraft skin defect inspection,more effectively than the attention mechanism and feature fusion *** with the Mask R-CNN and Mask Scoring R-CNN,the proposed method increased the segmentation precision by approximately 21%and 19.59%,*** results demonstrate that the proposed method performs favorably against the other two methods of pixellevel aircraft skin defect detection.

关键词： Aircraft skin Automatic non-destructive testing Defect inspection Instance segmentation Machine vision

Mothers’experiences of neonatal intensive care:A systematic review and implications for clinical practice

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World Journal of Clinical Cases 2021年第24期9卷 7062-7072页

作者： Li-Li Wang juan-juan Ma Hao-Hao meng Jie Zhou Department of Pediatrics Shenzhen Nanshan People’s HospitalShenzhen 518052Guangdong ProvinceChina Department of Nursing Shenzhen Shekou People’s HospitalShenzhen 518067Guangdong ProvinceChina

BACKGROUND Preterm birth is on the rise *** intensive care units(NICUs)have enabled many critically ill newborns to *** a premature baby is admitted to the NICU,the mother–infant relationship may be interrupted,affecting the mother's mental *** To examine the maternal emotions associated with having a child in the NICU and provide suggestions for clinical *** MEDLINE,CINAHL,PsychARTICLES,and PsychINFO were searched for relevant articles between 2005 to 2019,and six qualitative articles were chosen that explored the experiences of mothers who had a preterm infant in the *** thematic analysis method was used to identify the most common *** Four main themes of the experience of mothers who had a preterm infant in the NICU were identified:Negative emotional impacts on the mother,support,barriers to parenting,and establishment of a loving *** NICU environment is not conducive to mother-child bonding,but we stipulate steps that health care professionals can take to reduce the negative emotional toll on mothers of NICU babies.

关键词： Neonatal intensive care units Preterm infant Maternal experience Mother-infant bond Implication Systematic review