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    题名 作者 年代 出处 被引量
1Relationship of Helicobacterpylori eradication with gastric cancer and gastric mucosal histological changes: a 10-year follow-up study显示文摘Zhou Liya Lin Sanren Ding Shigang Huang Xuebiao Jin Zhu Cui Rongli Meng Lingmei Li Yuan Zhang Li Guo Changji Xue Yan Yan Xiu'e Zhang Jing 2014Chinese Medical Journal2014,,8:28
2Genetic analysis and gene fine mapping for a rice novel mutant(rl_(9(t)))with rolling leaf character显示文摘Leaf shape is an important parameter for ideotype breeding in rice, and the rolling of leaf is also beneficial to efficient ripening of grains. This encourages the explorations of new genes that regulate leaf shape. In this study, genetic analysis and gene mapping were carried out for a novel rolling leaf mutant identified from japonica variety Zhonghua 11. The SSR marker analysis showed that the mutant was controlled by a single recessive gene (rl9(t)) lo- cated on chromosome 9. Fine mapping of the Rl9(t) locus was conducted with 30 new STS markers de- veloped around Rl9(t) anchored region based on the sequence diversity between Nipponbare and 93-11. The fine mapping necessitated the contruction of a PAC contig encompassing the Rl9(t) locus, which was delimited to a 42 kb region. This could therefore en- hance the cloning of the target gene in further stud- ies.YAN Changjie YAN Song ZHANG Zhengqiu LIANG Guohua LU Jufei GU Minghong 2006Chinese Science Bulletin2006,51,1:22
3A Simple CRISPR/Cas9 System for Multiplex Genome Editing in Rice显示文摘Generating mutants bearing multiple gene modifications is essential for determining the functions of gene family members with redundant functions,or for analyzing epistatic relationships in genetic pathways.Using conventional methods,mutants with multiple gene mutations are generated by several rounds of intercrossing plants carrying a single mutation and identification of the offspring.This process is both time-Chun Wang Lan Shen Yaping Fu Changjie Yan Kejian Wang 2015Journal of Genetics and Genomics2015,42,12:22
4Introgression of qPE9-1 allele,conferring the panicle erectness,leads to the decrease of grain yield per plant in japonica rice(Oryza sativa L.)显示文摘圆锥花序建筑学是仔细与产量有关形成。qPE9-1 基因被证明了广泛地在产量很高的米饭栽培变种开发被过去常,授与在装饰用的梨树米饭的直立的圆锥花序特性。最近, qPE9-1 成功地被克隆;然而,谷物产量上的基因效果还每直立的圆锥花序等位基因 qPE9-1 的植物是争论的。在现在的学习,低垂的圆锥花序父母 Nongken 57,带 qpe9-1 等位基因,被用作周期性父母到连续地回交到从双 haploid (DH ) 的一根典型直立的圆锥花序线人口(Wuyunjing 8/Nongken 57 ) ,它以前被显示带 qPE9-1 等位基因。因此,一双 near-isogenic 线(无) 被开发。在无之间的农学的特点的比较证明当 qpe9-1 被 qPE9-1 代替时,圆锥花序建筑学从低垂树立被改变;而且,圆锥花序长度,植物高度, 1000 谷物重量和 tillers 显著地被减少,因而在 30% 每植物导致谷物产量的戏剧的减少。因此,我们断定 qPE9-1 是控制圆锥花序建筑学的一个主要因素,并且 qPE9-1 有多种的自然,与每植物的谷物产量上的否定效果。这结果强烈建议直立的圆锥花序等位基因 qPE9-1 应该在产量很高的繁殖实践和另外的有利基因被使用。另外,吃并且煮质量上的 qPE9-1 的效果也在现在的学习被讨论。Xiuhua Yi Zujian Zhang Shengyuan Zeng Chunyan Tian Juncheng Peng Min Li Yue Lu Qingcai Meng Minghong Gu Changjie Yan 2011Journal of Genetics and Genomics2011,38,5:20
5QTL editing confers opposing yield performance in different rice varieties显示文摘Grain yield is one of the most important and complex trait for genetic improvement in crops; it is known to be controlled by a number of genes known as quantitative trait loci(QTLs). In the past decade, many yield-contributing QTLs have been identified in crops.However, it remains unclear whether those QTLs confer the same yield performance in different genetic backgrounds. Here, we performed CRISPR/Cas_9-mediated QTL editing in five widely-cultivated rice varieties and revealed that the same QTL can have diverse, even opposing, effects on grain yield in different genetic backgrounds.Lan Shen Chun Wang Yaping Fu Junjie Wang Qing Liu Xiaoming Zhang Changjie Yan Qian Qian Kejian Wang 2018Journal of Integrative Plant Biology2018,60,2:18
6Meteorological control on CO_2 flux above broad-leaved Korean pine mixed forest in Changbai Mountains显示文摘The impacts of temperature, photosynthetic active radiation (PAR) and vapor pressure deficit (VPD) on CO2 flux above broad-leaved Korean pine mixed forest in the Changbai Mountains were studied based on eddy covariance and meteorological factors measurements.The results showed that, daytime CO2 flux was mainly controlled by PAR and they fit Michaelis-Menten equation. Meanwhile VPD also had an influence on the daytime flux. Drier air reduced the CO2 assimilation of the ecosystem, the drier the air, the more the reduction of the assimilation. And the forest was more sensitive to VPD in June than that in July and August. The respiration of the ecosystem was mainly controlled by soil temperature and they fit exponential equation. It was found that this relationship was also correlated with seasons; respiration from April to July was higher than that from August to November under the same temperature. Daily net carbon exchange of the ecosystem and the daily mean air temperature fit exponential equation. It was also found that seasonal trend of net carbon exchange was the result of comprehensive impacts of temperature and PAR and so on. These resulted in the biggest CO2 uptake in June and those in July and August were next. Annual carbon uptake of the forest ecosystem in 2003 was -184 gC. m-2.GUAN Dexin, WU Jiabing, YU Guirui, SUN Xiaomin, ZHAO Xiaosong, HAN Shijie & JIN Changjie Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China 2005Science China Earth Sciences2005,48,z1:15
7Development of gene-tagged molecular markers for starch synthesis-related genes in rice显示文摘Improving grain quality is an important goal in breeding new elite rice varieties,requiring effective tools for the identification of target genotypes.Molecular marker-aided selection(MAS),combined with conventional breeding approaches,enables us to pre-cisely identify the individual genotypes that are associated with different grain quality features,which can dramatically improve the breeding efficiency.However,to date,the number of molecular markers used in MAS for grain quality improvement is still somewhat limited.In this study,based on our previous study that rice grain quality is strongly associated with starch synthesis in the endosperm,we developed 51 gene-tagged molecular markers according to sequence variations in 18 starch synthesis-related genes from 16 typical rice cultivars.These markers can discriminate the different alleles among rice germplasms.These novel markers will provide effective tools in improving grain quality via the breeding new elite rice varieties.TIAN ZhiXi YAN ChangJie QIAN Qian YAN Song XIE HuiLan WANG Fang XU JieFen LIU GuiFu WANG YongHong LIU QiaoQuan TANG ShuZhu LI JiaYang GU MingHong 2010Chinese Science Bulletin2010,55,33:12
8Targeted mutagenesis of amino acid transporter genes for rice quality improvement using the CRISPR/Cas9 system显示文摘High grain protein content(GPC) reduces rice eating and cooking quality(ECQ). We generated OsAAP6 and OsAAP10 knockout mutants in three high-yielding japonica varieties and one japonica line using the CRISPR/Cas9 system. Mutation efficiency varied with genetic background in the T_0 generation, and GPC in the T_1 generation decreased significantly,owing mainly to a reduction in glutelin content. Amylose content was down-regulated significantly in some Osaap6 and all Osaap10 mutants. The increased taste value of these mutants was supported by Rapid Visco Analysis(RVA) profiles, which showed higher peak viscosity and breakdown viscosity and lower setback viscosity than the wild type. There were no significant deficiencies in agronomic traits of the mutants. Targeted mutagenesis of OsAAP6 and OsAAP10, especially OsAAP10, using the CRISPR/Cas9 system can rapidly reduce GPC and improve ECQ of rice, providing a new strategy for the breeding cultivars with desired ECQ.Shiyu Wang Yihao Yang Min Guo Chongyuan Zhong Changjie Yan Shengyuan Sun 2020The Crop Journal2020,8,3:11
9Aoyitake plagiogranite in western Tarim Block, NW China: Age, geochemistry, petrogenesis and its tectonic implications显示文摘SHRIMPP U-Pb zircon age and geochemical and Nd isotopic data are reported for the Aoyitake plagiogranite in western Tarim Block, NW China. The plagiogranite intruded the Middle Pro- terozoic and Lower Carboniferous with an exposure area of ca. 60 km2 and crystallized at 330.7±4.8 Ma. Rock types mainly include tonalite, trondhjemite and minor amounts of diorite and quartz-diorite. Feldspars in the rocks are dominated by oligoclase-andesine, and minor perthite observed locally. The granites are sodic with Na/K ratios (molar) between 4 and 87. Total REE (50-220 ppm) show a clear positive correlation with SiO2. There is no LRRE/HREE fractionation (LaN/YbN=0.5-1.5), me- dium negative Eu anomalies (δ Eu=0.3-0.6), high Y content and low Sr/Y ratio (~1.0). These granites exhibit relatively juvenile Nd T2DM model ages of 470 to 580 Ma and positive εNd(331 Ma) values of 6.23 to 7.65. The aforementioned characteristics are similar to those of ocean island or ocean ridge plagiogranites. However, the regional geology, especially its scale, precludes that the plagiogranite pluton was derived directly from fractionational crystallization of mantle-derived basaltic magma. We interpreted that the primary magma of the pluton might be tonalitic in composition generated by ca. 50% partial melting of the juvenile basaltic crust. The primary magma experienced intensive frac- tionational crystallization, and intruded into the middle to upper crusts to form the granite pluton. In combination with the previous regional geological data, it is concluded that the plagiogranite pluton was emplaced within the Tarim Block in respond to the Carboniferous continental rifting along the Tianshan orogenic belt.ZHANG Chuanlin1,2, YU Haifeng3, YE Haimin2, ZHAO Yu2 & ZHANG Dongsheng4 1. Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China 2. Nanjing Institute of Geology and Mineral Resources, Nanjing 210016, China 3. Tianjin Institute of Geology and Mineral Resources, Tianjin 300170, China 4. The 2nd Regional Geological Investigation Party, Xinjiang Bureau of Geology and Mineral Resources, Changji 831100, China 2006Science China Earth Sciences2006,49,11:11
10Rapid generation of genetic diversity by multiplex CRISPR/Cas9 genome editing in rice显示文摘The clustered regularly interspaced short palindromic repeats(CRISPR)-associated endonuclease 9(CRISPR/Cas9) system has emerged as a promising technology for specific genome editing in many species. Here we constructed one vector targeting eight agronomic genes in rice using the CRISPR/Cas9 multiplex genome editing system. By subsequent genetic transformation and DNA sequencing, we found that the eight target genes have high mutation efficiencies in the T_0 generation. Both heterozygous and homozygous mutations of all editing genes were obtained in T_0 plants. In addition, homozygous sextuple, septuple, and octuple mutants were identified. As the abundant genotypes in T_0 transgenic plants, various phenotypes related to the editing genes were observed. The findings demonstrate the potential of the CRISPR/Cas9 system for rapid introduction of genetic diversity during crop breeding.Lan Shen Yufeng Hua Yaping Fu Jian Li Qing Liu Xiaozhen Jiao Gaowei Xin Junjie Wang Xingchun Wang Changjie Yan Kejian Wang 2017Science China(Life Sciences)2017,60,5:11
11Flexible self-charging power units for portable electronics based on folded carbon paper显示文摘对便携式的电子学的迫切要求支持了高效率、持续、甚至可拉长的自我控告的力量来源的发展。在这个工作,我们建议为从人的运动和力量便携式计算机电子学收获机械精力基于合拢的碳(FC ) 统一纸的灵活自我控告的力量。现在的单位主要由摩擦电 nanogenerator (FC-TENG ) 和 supercapacitor (FC-SC ) 组成,基于合拢的复写纸精力 harvester 和存储设备分别地。这个有利几何图案向高幼仔模量复写纸提供优秀 stretchability 并且使力量单位能甚至在严重变丑下面工作,扭动,并且滚动,例如弯曲。另外,张力的紧张能被调节合拢三角的复写纸的合拢的角度最大化。而且,包装设备的防水性质使它可洗,保护它免受人的汗的伤害,并且使它能在严厉环境工作。最后,同样准备的自我控告的力量单位被把它放在人的身体上从手拍,踩的脚,并且手臂接触成功地驱动一块电子手表收获机械精力测试。这个工作表明可拉长的自我控告的力量单位的出色的潜力,它将进一步为便携 / 便携式的电子学支持高幼仔模量材料的发展。Changjie Zhou Yanqin Yang Na Sun Zhen Wen Ping Cheng Xinkai Xie Huiyun Shao Qingqing Shen Xiaoping Chen Yina Liu Zhong Lin Wang Xuhui Sun 2018Nano Research2018,11,8:9
12An analytical solution to the scattering of cylindrical SH waves by a partially filled semi-circular alluvial valley: near-source site effects显示文摘The earth's surface irregularities can substantially affect seismic waves and induce amplifi cations of ground motions. This study investigates whether and how the source characteristics affect the site amplifi cation effects. An analytical model of a line source of cylindrical waves impinging on an alluvial valley is proposed to link the source and site. The analytical solution to this problem proves one aspect of the strong effect of source on site amplifi cation, i.e., the wave curvature effect. It is found that the site amplifi cation depends on the source location, especially under conditions of a small source-to-site distance. Whether the displacement is amplifi ed or reduced and the size of the amplifi cation or reduction may be determined by the location of the source. It is suggested that traditional studies of site responses, which usually ignore the source effect, should be further improved by combining the source with site effects.Zhang Ning Gao Yufeng Yang Jie Xu Changjie 2015Earthquake Engineering and Engineering Vibration2015,14,2:9
13Rb-Sr and Sm-Nd Isochron Ages of the Dongmozhazhua and Mohailaheng Pb-Zn Ore Deposits in the Yushu area, southern Qinghai and Their Geological Implications显示文摘Located on the northeast margin of the Qiangtang terrane between the Jinshajiang suture zone and Bangonghu-Nujiang suture zone, the Dongmozhazhua and Mohailaheng Pb-Zn deposits in the Yushu area of Qinghai Province are representative Pb-Zn deposits of the Pb-Zn-Cu polymetallic mineralization belt in the northern part of the Nujiang-Lancangjiang-Jinshajiang area, which are in the front belt of the Yushu thrust nappe system. The formed environments of these two deposits are different from those of sediment-hosted base metal deposits elsewhere in the world. The authors hold that they were formed during the Indian-Asian continental collision and developed within the foldthrust belt combined with thrust and strike-slip-related Cenozoic basins in the interior of the collisional zone. Studying on the metallogenic epochs of these two deposits is helpful to the understanding of ore-forming regularity of the regional Pb-Zn-Cu mineralization belt and also to the search for new deposits in this region. The age of the Dongmozhazhua deposit has been determined by the Rb-Sr isochron method for sphalerite residues, whereas the age of the Mohailaheng deposit has been determined by the Rb-Sr isochron method for sphalerite residues and the Sm-Nd isochron method for fluorite. The age of the Dongmozhazhua deposit is 35.0±0.0 Ma((87Sr/86Sr)0=0.708807) for sphalerite residues. The age of the Mohailaheng deposit is 32.2±0.4 Ma((87Sr/86Sr)0=0.708514) for sphalerite residues and 31.8±0.3 Ma((143Nd/144Nd)0=0.512362) for fluorite with an average of 32.0 Ma. Together with the regional geological setting during mineralization, a possible tectonic model for metallogeny of the Dongmozhazhua and Mohailaheng Pb-Zn deposits has been established. These two ages are close to the ages of the Pb-Zn deposits in the Lanping and Tuotuohe basins, indicating that it is possible that the narrow 1000-kilometer-long belt controlled by a thrust nappe system on the eastern and northern margins of the Tibetan plateau could be a giant Pb-Zn mineralized belt.TIAN Shihong GONG Yingli YANG Zhusen HOU Zengqian LIU Yingchao SONG Yucai XUE Wanwen LU Haifeng WANG Fuchun ZHANG Yubao ZHU Tian YU Changjie 2014Acta Geologica Sinica(English Edition)2014,88,2:8
14Torsional vibration of a pipe pile in transversely isotropic saturated soil显示文摘This study considers the torsional vibration of a pipe pile in a transversely isotropic saturated soil layer. Based on Biot's poroelastic theory and the constitutive relations of the transversely isotropic medium, the dynamic governing equations of the outer and inner transversely isotropic saturated soil layers are derived. The Laplace transform is used to solve the governing equations of the outer and inner soil layers. The dynamic torsional response of the pipe pile in the frequency domain is derived utilizing 1D elastic theory and the continuous conditions at the interfaces between the pipe pile and the soils. The time domain solution is obtained by Fourier inverse transform. A parametric study is conducted to demonstrate the influence of the anisotropies of the outer and inner soil on the torsional dynamic response of the pipe pile.Zheng Changjie Hua Jianmin Ding Xuanming 2016Earthquake Engineering and Engineering Vibration2016,15,3:8
15Eddy flux corrections for CO_2 exchange in broad-leaved Korean pine mixed forest of Changbai Mountains显示文摘Based on analysis of mechanisms causing energy no-closure and nocturnal low fluxes issues for CO2 exchange studies by eddy covariance method, corrections were done with the raw data sets obtained from Changbai Mountains forest flux site, to evaluate the impacts of sonic anemometer tilt, frequency response limitations and advection on estimation of CO2 exchange, respectively. The results show that the planar fit coordinate transforming method is superior to the streamline coordinate transforming method in tilt correction. The latter could cause a systematical underestimation of eddy fluxes relating with the angle of sensor and terrain tilt. The underestimation of CO2 and energy fluxes for frequency response limitations average 3.0% and 2.0% during daytime, respectively, which increase by 9.0% and 5.5% during nighttime, respectively. The corrections of frequency response limitations are closely related to atmospheric stability. The advection loss of CO2 fluxes is dominated by nocturnal vertical advection, which is at least 18% when the horizontal advection is neglected. It is suggested that more work be done to understand the characteristics of horizontal advection and turbulent eddies under a complexcircumstance.WU Jiabing, GUAN Dexin, SUN Xiaomin, YU Guirui, ZHAO Xiaosong, HAN Shijie & JIN Changjie Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China Graduate school of the Chinese Academy of Sciences, Beijing 100093, China Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China 2005Science China Earth Sciences2005,48,z1:8
16Model tests on XCC-piled embankment under dynamic train load of high-speed railways显示文摘Piled embankments,which offer many advantages,are increasingly popular in construction of high-speed railways in China.Although the performance of piled embankment under static loading is well-known,the behavior under the dynamic train load of a high-speed railway is not yet understood.In light of this,a heavily instrumented piled embankment model was set up,and a model test was carried out,in which a servo-hydraulic actuator outputting M-shaped waves was adopted to simulate the process of a running train.Earth pressure,settlement,strain in the geogrid and pile and excess pore water pressure were measured.The results show that the soil arching height under the dynamic train load of a high-speed railway is shorter than under static loading.The growth trend for accumulated settlement slowed down after long-term vibration although there was still a tendency for it to increase.Accumulated geogrid strain has an increasing tendency after long-term vibration.The closer the embankment edge,the greater the geogrid strain over the subsoil.Strains in the pile were smaller under dynamic train loads,and their distribution was different from that under static loading.At the same elevation,excess pore water pressure under the track slab was greater than that under the embankment shoulder.Niu Tingting Liu Hanlong Ding Xuanming Zheng Changjie 2018Earthquake Engineering and Engineering Vibration2018,17,3:6
17Suppression of murine breast cancer metastasis by selective inhibition of CXCR4 by synthetic polypeptide derived from viral macrophage inflammatory protein Ⅱ显示文摘Stromal cell-derived factor-1 and its receptor CXC chemokine receptor-4(CXCR4)have been implicated in breast cancer metastasis.A significant association between HER2 and CXCR4 expression has been observed in human breast tumor tissues,and overexpression of CXCR4 is essential for HER2-mediated tumor metastasis.Moreover,CXCR4 expression is low in normal breast tissues and high in malignant tumors,suggesting that a blockade of CXCR4 may limit tumor metastasis.The present study investigated the action of a synthetic antagonist 21-mer peptide derived from viral macrophage inflammatory protein Ⅱ against CXCR4(NT21MP)in inhibiting metastasis in vitro and in vivo.The results showed that chemotaxis of SKBR3 cells toward SDF-1αwas reduced by NT21MP in a dose-dependent manner(P<0.05).NT21MP inhibited tumor growth at 500μg/kg and in combination with Herceptin,the anti-HER2 antibody.The in vivo metastatic assay showed that NT21MP significantly inhibited pulmonary metastasis,and the number of metastatic tumor nodes on the surface of the lung was greatly decreased.Compared with the saline-treated control group,PCNA expression was dose-dependently decreased by NT21MP,the percentage of apoptotic cells was increased,and CXCR4 mRNA and protein expression were downregulated.In conclusion,NT21MP inhibits cellular proliferation,promotes apoptosis by downregulating CXCR4 expression,and suppresses the progression of primary and metastatic tumors.CXCR4 may be a useful therapeutic target for breast cancer,and NT21MP may serve as a potential target drug for the treatment of breast cancer metastasis.YANG QingLin DING YongXing CHEN ChangJie TANG Jie ZHANG Ju YANG ZhiFeng 2010Chinese Science Bulletin2010,55,20:6
18Causal effects of shelter forests and water factors on desertification control during 2000–2010 at the Horqin Sandy Land region, China显示文摘The Horqin Sandy Land(HSL), the largest sandy land in the semi-arid agro-pastoral ecotone of Northeast China, has been subject to desertification during the past century. In response, and to control the desertification,government implemented the Three-North Shelter/Protective Forest Program, world's largest ecological reforestation/afforestation restoration program. The program began in1978 and will continue for 75 years until 2050. Understanding the dynamics of desertification and its driving forces is a precondition for controlling desertification.However, there is little evidence to directly link causal effects with desertification process(i.e., on the changing area of sandy land) because desertification is a complex process,that can be affected by vegetation(including vegetation cover and extent of shelter forests) and water factors such as precipitation, surface soil moisture, and evapotranspiration.The objectives of this study were to identify how influencing factors, especially shelter forests, affected desertification in HSL over a recent decade. We used Landsat TM imagery analysis and path analysis to identify the effects of spatiotemporal changes in water and vegetation parameters during2000–2010. Desertification was controlled during the study period, as indicated by a decrease in desert area at a rate of163.3 km2year-1and an increase in the area with reduced intensity or extent of desertification. Total vegetation cover in HSL increased by 10.6 % during the study period and this factor exerted the greatest direct and indirect effects on slowing desertification. The contribution of total vegetation cover to controlling desertification increased with the intensity of desertification. On slightly and extremely severe desertified areas, vegetation cover contributed 5 and 42 % of the desertification reduction, respectively. There were significant correlations between total vegetation cover and water conditions(i.e., evapotranspiration and precipitation)and the area of shelter forests(P \ 0.0001), in which water conditions and the existence of shelter forests contributed49.7 and 12.8 % to total vegetation cover, respectively. The area of shelter forests increased sharply due to program efforts, but only shrub forests had significant direct effects on reducing the area of desertification categorized as slightly desertified. The reason for the lack of direct effect of increased arbor forests(accounting for 95.3 % of the total increase in shelter forests) on reducing desertification might be that the selected arbor species were not suited to water conditions(low precipitation, high evapotranspiration) prevailing at HSL. The establishment of shelter forests aided control of desertification in the HSL region, but the effect was less than expected. Effective control of desertification in the HSL region or other similar sandy areas will require greater improvements in vegetation cover. In particular,shrub species should be selected for plantation with reference to their potential to survive and reproduce in the harsh climatic and weather conditions typical of desertified areas.Qiaoling Yan Jiaojun Zhu Xiao Zheng Changjie Jin 2015Journal of Forestry Research2015,26,1:5
19Enhancing the expansion of a plasma shockwave by crater-induced laser refocusing in femtosecond laser ablation of fused silica显示文摘The dynamics of plasma and shockwave expansion during two femtosecond laser pulse ablation of fused silica are studied using a time-resolved shadowgraph imaging technique. The experimental results reveal that during the second pulse irradiation on the crater induced by the first pulse, the expansion of the plasma and shockwave is enhanced in the longitudinal direction. The plasma model and Fresnel diffraction theory are combined to calculate the laser intensity distribution by considering the change in surface morphology and transient material properties. The theoretical results show that after the free electron density induced by the rising edge of the pulse reaches the critical density, the originally transparent surface is transformed into a transient high-reflectivity surface(metallic state). Thus, the crater with a concave-lens-like morphology can tremendously reflect and refocus the latter part of the laser pulse, leading to a strong laser field with an intensity even higher than the incident intensity. This strong refocused laser pulse results in a stronger laser-induced air breakdown and enhances the subsequent expansion of the plasma and shockwave. In addition, similar shadowgraphs are also recorded in the single-pulse ablation of a concave microlens, providing experimental evidence for the enhancement mechanism.QINGSONG WANG LAN JIANG JINGYA SUN CHANGJI PAN WEINA HAN GUOYAN WANG HAO ZHANG COSTAS P.GRIGOROPOULOS YONGFENG LU 2017Photonics Research2017,5,5:5
20Modelling long-term deformation of granular soils incorporating the concept of fractional calculus显示文摘Many constitutive models exist to characterise the cyclic behaviour of granular soils but can only simulate deformations for very limited cycles. Fractional derivatives have been regarded as one potential instrument for modelling memory-dependent phenomena. In this paper, the physical connection between the fractional derivative order and the fractal dimension of granular soils is investigated in detail.Then a modified elasto-plastic constitutive model is proposed for evaluating the long-term deformation of granular soils under cyclic loading by incorporating the concept of factional calculus. To describe the flow direction of granular soils under cyclic loading, a cyclic flow potential considering particle breakage is used. Test results of several types of granular soils are used to validate the model performance.Yifei Sun Yang Xiao Changjie Zheng Khairul Fikry Hanif 2016Acta Mechanica Sinica2016,32,1:5
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