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Experimental study of partially-cured Z-pins reinforced foam core composites:K-Cor sandwich structures

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Chinese Journal of Aeronautics 2014年第1期27卷 153-159页

作者： zheng Yingying Xiao Jun duan Mufeng Li Yong College of Materials Science and Technology Nanjing University of Aeronautics and Astronautics

This paper presents an experimental study of a novel K-Cor sandwich structure rein- forced with partially-cured Z-pins. The influence of pultrusion processing parameters on Z-pins characteristics was studied and the effect of Z-pins on mechanical properties was disclosed. Differential scanning calorimetry （DSC） and optical microscopy （OM） methods were employed to determine the curing degree of as-prepared Z-pins and observe the implanted Z-pins in the K-Cor structure. These partially-cured Z-pins were treated with a stronger bonding link between face sheets and the foam core by means of a hot-press process, thereby decreasing burrs and cracking defects when the Z-pins were implanted into the Rohacell foam core. The results of the out-of-plane tensile tests and the climbing drum peel （CDP） tests showed that K-Cor structures exhibited superior mechanical performance as compared to X-Cor and blank foam core. The observed results of failure modes revealed that an effective bonding link between the foam core and face sheets that was provided from partially-cured Z-pins contributed to the enhanced mechan- ical performances of K-Cor sandwich structures.

关键词： Composite materials K-Cor sandwich structuresMechanical performance Partially-cured Z-pins Foam core composites

On the “spring predictability barrier” for strong El Nio events as derived from an intermediate coupled model ensemble prediction system

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Science China Earth Sciences 2017年第9期60卷 1614-1631页

作者： QI QianQian duan WanSuo zheng Fei TANG YouMin State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China University of Chinese Academy of Sciences Beijing 100049 China International Center for Climate and Environment Science Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Second Institute of Oceanology State Oceanic Administration Hangzhou 310012 China

Using predictions for the sea surface temperature anomaly(SSTA) generated by an intermediate coupled model(ICM)ensemble prediction system(EPS), we first explore the "spring predictability barrier"(SPB) problem for the 2015/16 strong El Nio event from the perspective of error growth. By analyzing the growth tendency of the prediction errors for ensemble forecast members, we conclude that the prediction errors for the 2015/16 El Nio event tended to show a distinct season-dependent evolution, with prominent growth in spring and/or the beginning of the summer. This finding indicates that the predictions for the 2015/16 El Nio occurred a significant SPB phenomenon. We show that the SPB occurred in the 2015/16 El Nio predictions did not arise because of the uncertainties in the initial conditions but because of model errors. As such, the mean of ensemble forecast members filtered the effect of model errors and weakened the effect of the SPB, ultimately reducing the prediction errors for the 2015/16 El Nio event. By investigating the model errors represented by the tendency errors for the SSTA component,we demonstrate the prominent features of the tendency errors that often cause an SPB for the 2015/16 El Nio event and explain why the 2015/16 El Nio was under-predicted by the ICM EPS. Moreover, we reveal the typical feature of the tendency errors that cause not only a significant SPB but also an aggressively large prediction error. The feature is that the tendency errors present a zonal dipolar pattern with the west poles of positive anomalies in the equatorial western Pacific and the east poles of negative anomalies in the equatorial eastern Pacific. This tendency error bears great similarities with that of the most sensitive nonlinear forcing singular vector(NFSV)-tendency errors reported by duan et al. and demonstrates the existence of an NFSV tendency error in realistic predictions. For other strong El Nio events, such as those that occurred in 1982/83 and 1997

关键词： 2015/16 strong El Nio event Spring predictability barrier Initial errors Model errors

Molecular regulation mechanism of intestinal stem cells in mucosal injury and repair in ulcerative colitis

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World Journal of Gastroenterology 2023年第16期29卷 2380-2396页

作者： Lie zheng Sheng-Lei duan Department of Gastroenterology Shaanxi Hospital of Traditional Chinese MedicineXi’an 730000Shaanxi ProvinceChina

Ulcerative colitis(UC)is a chronic nonspecific inflammatory disease with complex *** main pathological changes were intestinal mucosal *** repeat-containing G protein coupled receptor 5(LGR5)-labeled small intestine stem cells(ISCs)were located at the bottom of the small intestine recess and inlaid among paneth ***5+small ISCs are active proliferative adult stem cells,and their self-renewal,proliferation and differentiation disorders are closely related to the occurrence of intestinal inflammatory *** Notch signaling pathway and Wnt/β-catenin signaling pathway are important regulators of LGR5-positive ISCs and together maintain the function of LGR5-positive *** importantly,the surviving stem cells after intestinal mucosal injury accelerate division,restore the number of stem cells,multiply and differentiate into mature intestinal epithelial cells,and repair the damaged intestinal ***,in-depth study of multiple pathways and transplantation of LGR5-positive ISCs may become a new target for the treatment of UC.

关键词： Molecular regulation Mucosal injury Regeneration Ulcerative colitis

Electron and configuration engineering of atomic Cu and multioxidated Cu_(2+1)O centers via gasifiable reductant strategy for efficient oxygen reduction toward Zn-air battery

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Nano Research 2023年第2期16卷 2383-2391页

作者： Hongbin Li Jia-Jia zheng Mingfan Yang Jingui duan State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China Laboratory of Theoretical and Computational Nanoscience National Center for Nanoscience and TechnologyChinese Academy of SciencesBeijing 100190China

Efforts in a large number of transition metal-carbon systems are devoted to the development of efficient catalysts for oxygen reduction reaction(ORR).However,unsatisfied O_(2)adsorption and slow reduction of OH*at the active centers hinder the further development of these *** here report a gasifiable reductant strategy,of which a new Cu-based metal organic framework(MOF:termed NTU-83)nanosheet was co-pyrolyzed with melamine to produce the N-coordinated atomic Cu and multi-oxidated Cu_(2+1)O active centers on the carbon foam with ultrathin *** engineered electrons and configuration of the active centers boost the catalyst(Cu/NC-1000)to show superior ORR activity(E_(1/2)=0.85 V),excellent stability,and methanol *** modeling calculation and controlled experiments reveal that the Cu_(2+1)O species play a crucial role in kinetically accelerated adsorption and activation of O_(2),while the N_(4)coordinated atomic Cu facilitates fast reduction of OH*.Such characteristics endow the Zn-air battery that containing Cu/NC-1000 as air cathode to show a high peak power density(138 mW·cm^(−2)),a high specific capacity of 763 mAh·gZn^(−1),and outstanding long-term cycle *** plausible mechanism and excellent performance show that gasifiable reductant strategy opens up a new route for regulation of the electronic of active sites but also provides a candidate for the practical application in energy conversion/storage devices.

关键词： metal organic framework nanosheet carbon foam atomic Cu Cu_(2+1)O nanosheet electron and configuration engineering

Medical Knowledge Graph:Data Sources,Construction,Reasoning,and Applications

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Big Data Mining and Analytics 2023年第2期6卷 201-217页

作者： Xuehong Wu Junwen duan Yi pan Min Li Computer Science and Engineering Central South UniversityChangsha 410083China School of Computer Science Hunan First Normal UniversityChangsha 410006China School of Computer Science and Engineering Central South UniversityChangsha 410083China Computer Science and Control Engineering Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518000China

Medical knowledge graphs(MKGs)are the basis for intelligent health care,and they have been in use in a variety of intelligent medical ***,understanding the research and application development of MKGs will be crucial for future relevant research in the biomedical *** this end,we offer an in-depth review of MKG in this *** research begins with the examination of four types of medical information sources,knowledge graph creation methodologies,and six major themes for MKG ***,three popular models of reasoning from the viewpoint of knowledge reasoning are discussed.A reasoning implementation path(RIP)is proposed as a means of expressing the reasoning procedures for *** addition,we explore intelligent medical applications based on RIP and MKG and classify them into nine major ***,we summarize the current state of MKG research based on more than 130 publications and future challenges and opportunities.

关键词： medical knowledge graph knowledge graph construction knowledge reasoning intelligent medical applications intelligent healthcare

The rate dependence of the dielectric strength of dielectric elastomers

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International Journal of Smart and Nano Materials 2024年第1期15卷 110-126页

作者： Xianghe zheng Jianyou Zhou pan Jia zheng Zhong School of Science Harbin Institute of TechnologyShenzhenChina

Elastomers are widely used in electronics and electrical devices,either as insulators or *** insulation and actuation performance of elastomers are highly suscepti-ble to their dielectric *** the factors that influ-encethedielectricstrength ofelastomers,material viscoelasticity is an important factor that needs further *** the material viscoelasticity is often character-ized by rate-dependent behaviors,we present two different sample configurations to experimentally examine the electrical and mechanical rate dependence of the dielectric strength of VHB 4905 *** pre-stretch ratio of 4,the improve-ment of the dielectric strength is about 30%from voltage ramp of 50 V/s to 800 V/***,with an in-house biaxial test platform,the effect of the stretching rate on the dielectric strength is examined for the first *** improvement of the dielectric strength is about 35%from stretching rate of 0.1 mm/s to 5 mm/***,a dielectric strength predictor based on configurational stress is adopted to describe the experimental *** to the predictor,the loading rate affects the dielectric strength of the elastomer mainly by influencing the evolution of the inelastic deformation.

关键词： Dielectric strength dielectric elastomers material viscoelasticity rate-dependence configurational stress

Impacts of advanced treatment processes on elimination of antibiotic resistance genes in a municipal waste water treatment plant

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Frontiers of Environmental Science & Engineering 2019年第3期13卷 69-78页

作者： Lian Yang Qinxue Wen Zhiqiang Chen Ran duan pan Yang State Key Laboratory of Urban Water Resource and Environment Harbin Institute of Technology (SKLUWRE HIT) Harbin 150090 China National & Local Joint Engineering Laboratory for Municipal Sewage Resource Utilization Technology Suzhou University of Science and Technology Suzhou 215009 China

Antibiotic resistance genes (ARGs) pose a serious threat to public health. Wastewater treatment plants (WWTPs) are essential for controlling the release of ARGs into the environment. This study investigated ARG distribution at every step in the treatment process of a municipal WWTP located in Harbin for six consecutive months. Changes in ARG distribution involved in two advanced secondary effluent treatment processes, ozonation and granular activated carbon (GAC) adsorption, were analyzed. Biological treatment resulted in the highest ARG removal (0.76-1.94 log reduction), followed by ultraviolet (UV) disinfection (less than 0.5-log reduction). Primary treatment could not significantly remove ARGs. ARG removal efficiency increased with an increase in the ozone dose below 40 mg/L. However, amorphous GAC (AGAC) adsorption with a hydraulic retention time (HRT) of 1 h showed better removal of ARGs, total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP) than ozonation at a 60 mg/L dose. UV treatment could efficiently reduce the relative ARG abundance, despite presenting the lowest efficiency for the reduction of absolute ARG abundance compared with GAC and ozone treatments. The combination of ozone and AGAC can significantly improve the removal of ARGs, TOC, TN and TP. These results indicate that a treatment including biological processing, ozonation, and AGAC adsorption is a promising strategy for removing ARGs and refractory organic substances from sewage.

关键词： Antibiotic resistance genes (ARGs) Wastewater treatment plant (WWTP) Ultraviolet (UV) Ozonation Granular activated carbon (GAC)

Synthesis and Characterization of a Novel Functional Biodegradable Copolymer-Poly(lactic acid-4-hydroxyproline-polyethylene glycol)

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Chinese Chemical Letters 2006年第8期17卷 1125-1128页

作者： Jiu Fang duan Yu Bin zheng Department of Polymer Science Dalian University of Technology Dalian 116012

A series of poly（lactic acid-4-hydroxyproline-polyethylene glycol）（PLA-Hpr-PEG） copolymers were synthesized by direct melt copolymerization of D,L-lactic acid and 4-hydroxyproline with different feed amount of polyethylene glycol （PEG） 0.1%, 0.5%, 1% and 5%, respectively. The properties of these copolymers were characterized by using IR spectroscopy, proton nuclear magnetic resonance （1H-NMR） spectroscopy, gel permeation chromatography （GPC）, X-ray diffraction and differential scaning calorimetry （DSC）. PLA-Hpr-PEG are amorphous copolymers. Copolymers showed increasing water uptake capacity with increasing PEG percentage in the feed, which result in an increasing degradable rate in phosphate buffer solution （pH 7.4） at 37℃.

关键词： Lactic acid 4-hydroxyproline polyethylene glycol.

A Model-Embedded Trend Test with Incorporating Hardy-Weinberg Equilibrium Information

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Journal of Systems Science & Complexity 2017年第1期30卷 101-110页

作者： HU Xiaonan duan Xiaogang pan Dongdong ZHANG Sanguo LI Qizhai School of Mathematical Sciences University of Chinese Academy of Sciences Beijing 100049 China KeyLaboratory of Big Data Mining and Knowledge Management Chinese Academy of Sciences Beijing 100190China. School of Statistics Beijing Normal University Beijing 100875 China. Department of Statistics Yunnan University Kunming 650091 China Key Laboratory of Systems and Control Academy of Mathematics and Systems Science Chinese Academy ofSciences Beijing 100190 China.

The genetic models are greatly important in the analysis of genetic epidemiologic studies and many of the studies are conducted using the trend test under the additive model. However, for many complex diseases and traits, the underlying genetic model for a genetic locus is usually uncertain. So a robust test free of genetic model is appropriate. In this paper, the authors propose a model-embedded trend test by incorporating Hardy-Weinberg equilibrium information and obtain the explicit formula to calculate its statistical significance. Extensive simulation studies show the proposed test is more robust than the existing procedures. Finally, a real application is further analyzed to show the performance of the proposed test.

关键词： Genetic model hardy-weinberg equilibrium power robust trend test.