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| 1 | Nonlinear Vibration of A Loosely Supported Curved Pipe Conveying Pulsating Fluid under Principal Parametric Resonance显示文摘In this paper,the nonlinear dynamics of a curved pipe is investigated in the case of principal parametric resonance due to pulsating flow and impact with loose supports.The coupled in-plane and out-of-plane governing equations with the consideration of von Karman geometric nonUnearity are presented and discretized via the differential quadrature method(DQM).The nonlinear dynamic responses are calculated numerically to demonstrate the influence of pulsating frequency.Finally,the impact is taken into consideration.The influence of clearance on frettingwear damage,such as normal work rate,contact ratio and impact force level,is demonstrated. | Yangyang Luo Min Tang Qiao Ni Yikun Wang Lin Wang | 2016 | Acta Mechanica Solida Sinica2016，29，5： | 5 |
| 2 | Biomechanism of impact resistance in the woodpecker's head and its application显示文摘The woodpecker does not suffer head/eye impact injuries while drumming on a tree trunk with high acceleration(more than 1000×g) and high frequency.The mechanism that protects the woodpecker's head has aroused the interest of ornithologists,biologists and scientists in the areas of mechanical engineering,material science and electronics engineering.This article reviews the literature on the biomechanisms and materials responsible for protecting the woodpecker from head impact injury and their applications in engineering and human protection. | WANG LiZhen LU Shan LIU XiaoYu NIU XuFeng WANG Chao NI YiKun ZHAO MeiYa FENG ChengLong ZHANG Ming FAN YuBo | 2013 | Science China(Life Sciences)2013，56，8： | 3 |
| 3 | Impact of Robinia pseudoacacia stand conversion on soil properties and bacterial community composition in Mount Tai,China显示文摘Background:Robinia pseudoacacia is a widely planted pioneer tree species in reforestations on barren mountains in northern China.Because of its nitrogen-fixing ability,it can play a positive role in soil and forest restoration.After clearcutting of planted stands,R.pseudoacacia stands become coppice plantations.The impacts of shifting from seedling to coppice stands on soil bacterial community and soil properties have not been wel described.This study aims to quantify how soil properties and bacterial community composition vary between planted seedling versus coppice stands.Methods:Nine 20 m×20 m plots were randomly selected in seedling and coppice stands.The bulk soil and rhizosphere soil were sampled in summer 2017.Bulk soil was sampled at 10 cm from the soil surface using a soil auger.Rhizosphere soil samples were col ected using a brush.The soil samples were transported to the laboratory for chemical analysis,and bacterial community composition and diversity was obtained through DNA extraction,16 S r RNA gene amplification and high-throughput sequencing.Results:The results showed that,compared to seedling plantations,soil quality decreased significantly in coppice stands,but without affecting soil exchangeable Mg^(2+) and K^(+).Total carbon(C)and nitrogen(N)were lower in the rhizosphere than in bulk soil,whereas nutrient availability showed an opposite trend.The conversion from seedling to coppice plantations was also related to significant differences in soil bacterial community structure and to the reduction of soil bacterialα-diversity.Principal component analysis(PCA)showed that bacterial community composition was similar in both bulk and rhizosphere soils in second-generation coppice plantations.Special y,the conversion from seedling to coppice stands increased the relative abundance of Proteobacteria and Rhizobium,but reduced that of Actinobacteria,which may result in a decline of soil nutrient availability.Mantel tests revealed that C,N,soil organic matter(SOM),nitrate nitrogen(NO^(-)+(3)-N)and available phosphorus positively correlated with bacterial community composition,while a variation partition analysis(VPA)showed that NO^(-)+(3)-N explained a relatively greater proportion of bacterial distribution(15.12%),compared with C and SOM.Surprisingly,N showed no relationship with bacterial community composition,which may be related to nitrogen transportation.Conclusions:The conversion from seedling to coppice stands reduced soil quality and led to spatial-temporal homogenization of the soil bacterial community structure in both the rhizosphere and bulk soils.Such imbalance in microbial structure can accelerate the decline of R.pseudoacacia.This may affect the role of R.pseudoacacia coppice stands in soil and forest restoration of barren lands in mountain areas. | Kun Li Xu Han Ruiqiang Ni Ge Shi Sergio de-Miguel Chuanrong Li Weixing Shen Yikun Zhang Xingzhong Zhang | 2021 | Forest Ecosystems2021，8，2： | 1 |
| 4 | Exploring the mechanism of Xiaopi Hewei capsule in treating functional dyspepsia based on network pharmacology显示文摘Objective:Functional dyspepsia(FD)is a widely prevalent gastrointestinal disorder throughout the world,whereas the efficacy of current treatment in the Western countries is limited.The traditional Chinese herbal formula Xiaopi Hewei capsule(XHC)is a clinically validated remedy in treating FD,but there is no literature expounds the underlying therapeutic mechanism of XHC so far.Methods:In the present study,the network pharmacology technology was used to explore the therapeutic mechanism of XHC in treating FD.We obtained relative compounds of XHC,potential targets of these compounds and FD-related targets by retrieving particular websites.Based on the matching results between XHC potential targets and disease targets,Protein-Protein Interaction(PPI)network was constructed to screen the hub targets by topology.Furthermore,DAVID bioinformatics resources were utilized for the enrichment analysis on GO and KEGG.Results:A total of 62 active compounds and 547 putative identified targets were screened from XHC,of which 241 overlapped with the targets of FD and were considered potential therapeutic targets.14 hub genes were recognized as potential targets of treatments.Moreover,the results of DAVID enrichment analysis indicated that XHC participated in the complex treating effects associated with anti-depression,inflammatory reaction and eradicating Helicobacter Pylori(HP).Molecular docking stimulation results showed that most bioactive compounds of XHC had a strong binding efficiency with hub genes.Conclusions:This study demonstrated that XHC has the characteristics of multi-compounds,multi-targets and multi-pathways in treating FD,which provides the theoretical basis for further research of XHC. | Runhua Liu Yu Sun Shiting Ni Jiaqi Wang Hao Wu Yuxia Qu Chenning Zhang Yikun Sun | 2020 | TMR Modern Herbal Medicine2020，3，4： | 0 |
| 5 | Biological analysis of woodpecker’s brain after impact experiments显示文摘Woodpeckers can withstand a fierce impact during pecking.Previous studies have focused on the biomechanical analysis of the pecking process,the properties of the beak and hyoid bone of woodpecker;however,the biological characteristics of the woodpecker brain are also important in resisting impact injuries.We employed impact experiments and biological analysis in normal and injured brains to reveal the impact-resistant biological characteristics of woodpecker brains,as well as the impact energy’s biological effects on the woodpecker brain.The hoopoe,which has a similar size but only a slight pecking behavior,was selected as the control group to compare brain morphology and neuronal cells differences in normal brains between woodpecker and hoopoe by sectioning and staining.A loading device was designed to conduct a quantifiable impact energy to the woodpeckers’head.Four groups of woodpeckers were impacted with the same energy on the forehead,beak,tempus and occiput,respectively.Biological changes in the injured brains were evaluated by Nissl staining and enzyme-linked immunosorbent assay.The results showed that:(1)woodpeckers had a larger cerebellum and a higher density of Nissl bodies than hoopoe;(2)Nissl apoptosis appeared in the brain samples after the forehead and the occiput impact experiments,but no obvious Nissl body apoptosis was observed after impact on the tempus and the beak;(3)β-amyloid protein accumulated in the normal status woodpecker brain.This study reveals that:woodpecker brain morphology is well-adapted to impact,woodpecker heads display location-dependent protective performance,with beak and tempus regions having a better protective performance than the forehead and occiput,Nissl apoptosis appears in injured woodpecker brains,and that the accumulation ofβ-amyloid protein does not show a direct relationship with the injury state of woodpecker’s brain tissue in our study. | XU Peng NI YiKun LIU JingLong ZHANG WeiRong LIU SiJian WANG LiZhen FAN YuBo | 2021 | Science China(Technological Sciences)2021，64，5： | 0 |
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