Implementation of a coupled plastic damage distinct lattice spring model for dynamic crack propagation in geomaterials          下载免费PDF全文

Chao Jiang  Gao‐Feng Zhao 《国际地质力学数值与分析法杂志》2018,42(4):674-693

This paper studies dynamic crack propagation by employing the distinct lattice spring model (DLSM) and 3‐dimensional (3D) printing technique. A damage‐plasticity model was developed and implemented in a 2D DLSM. Applicability of the damage‐plasticity DLSM was verified against analytical elastic solutions and experimental results for crack propagation. As a physical analogy, dynamic fracturing tests were conducted on 3D printed specimens using the split Hopkinson pressure bar. The dynamic stress intensity factors were recorded, and crack paths were captured by a high‐speed camera. A parametric study was conducted to find the influences of the parameters on cracking behaviors, including initial and peak fracture toughness, crack speed, and crack patterns. Finally, selection of parameters for the damage‐plasticity model was determined through the comparison of numerical predictions and the experimentally observed cracking features.  相似文献   

Fast genetic mapping in barley: case studies of cuticle mutants using RNA-sequencing     

XiaoFeng Li  Chao Li  Qin Zhou  GuoXiong Chen  PengShan Zhao 《寒旱区科学》2020,12(3):180-188

Barley(Hordeum vulgare L.) is one of the earliest domesticated crop species and ranked as the fourth largest cereal production worldwide. Forward genetic studies in barley have greatly advanced plant genetics during the last century; however, most genes are identified by the conventional mapping method. Array genotyping and exome-capture sequencing have also been successfully used to target the causal mutation in barley populations, but these techniques are not widely adopted because of associated costs and partly due to the huge genome size of barley. This review summarizes three mapping cases of barley cuticle mutants in our laboratory with the help of RNA-sequencing. The causal mutations have been successfully identified for two of them and the target genes are located in the pericentromeric regions. Detailed information on the mapping-by-sequencing, mapping-and-sequencing, and RNA-sequencing assisted linkage mapping are presented and some limitations and challenges on the mapping assisted by RNA sequencing are also discussed. The alternative and elegant methods presented in this review may greatly accelerate forward genetics of barley mapping, especially for laboratories without large funding.  相似文献   

基于GPIB接口的计数器数据采集与控制软件   总被引：2，自引：1，他引：1  

杨旭海  胡永辉  李志刚 《时间频率学报》2002,25(1):43-46

在Windows平台上 ,使用VC 6 .0开发了一套基于GPIB接口的计数器数据采集与控制软件 ,其特点是采用了多线程机制 ,可实现对计数器的控制 ,以及数据的采集与实时显示。  相似文献   

Geochemical survey of thermal system in Northeast China and their geothermometric characters     

MohammedHazaea HUKe MohammedMattash CHENBing M.O.AI-JabaliAref MohammedAbdussalam 《东北亚地学研究》2004,7(2):181-184

The chemical composition of several thermal springs around Changbaishan area has been investigated. Cenozoic basaltic rocks are widely distributed in Northeast China and geothermal characteristics have been described. About one hundred hot springs exist around Changhaishan Volcano at the border between China and D.P.R.Korea with high temperature about 82~C. The pH values of the spring water range from 6.9 to 7.1 and the total flow rate is about 4.8 L/sec. The chemical composition of the thermal springs is sodium carbonate; the high-mineral contents of thermal water are believed to have medicinal properties. Bathhouses are already built along the hot springs to take the advantage of the supposed healing properties. The high quality of those hot springs is believed to be utilitized for mineral water. The chemical equilibrium temperatures were estimated at about 160℃ based on the Na-K-Ca geochemical thermometer.  相似文献   

一种基于特征信息的车牌识别方法   总被引：3，自引：0，他引：3  

胡强  楼新远  段国兵 《成都信息工程学院学报》2004,19(3):345-348

根据中国车辆牌照本身的现有特征信息,提出一种车牌识别方法.采用全局动态阈值法进行二值化处理图像,牌照定位算法简单迅速,字符分割参考垂直投影间隔和字符的纵横比.实验结果表明,这种方法具有良好的环境适应性和鲁棒性.  相似文献   

测定天琴RR变星金属丰度的方法     

吴潮  胡景耀  赵永恒 《天文学进展》2006,24(4):308-318

银晕中天琴RR变星金属丰度的测定对于研究银河系晕的形成和演化具有重要的意义．在当前的技术条件下,高分辨光谱的方法难以测量银晕中较暗的天琴RR变星的金属丰度．高分辨光谱测定金属丰度的方法对恒星大气模型的依赖性较高,而恒星脉动引起的复杂大气状况对于建立正确的大气模型本身就是挑战．△S光谱方法、Caby测光方法和光变曲线的参数方法则弥补了高分辨光谱方法的不足,将能测量更远距离上的天琴RR变星的金属丰度．着重介绍了这3种方法发展的历史、具体的观测流程以及需要注意的问题。通过比较这3种方法的优劣,为实际观测时方法的选用提供借鉴。  相似文献   

SDSS J143030.22-001115.1： A Misclassified Narrow-line Seyfert 1 Galaxy with Flat X-ray Spectrum     

Wei-Hao Bian  Quan-Ling Cui  Li-Hua Chao Department of Physics  Institute of Theoretical Physics  Nanjing Normal University  Nanjing Key Laboratory for Particle Astrophysics  Institute of High Energy Physics  Chinese Academy of Sciences  Beijing 《中国天文和天体物理学报》2006,6(3):281-286

We used multi-component profiles to model the Hβ and [OⅢ]λλ4959,5007 lines of SDSS J143030.22-001115.1, a narrow-line Seyfert 1 galaxy (NLS1) in a sample of 150 NLS1 candidates selected from the Sloan Digital Sky Survey (SDSS), Early Data Release (EDR). After subtracting the Hβ contribution from narrow line regions (NLRs), we found that its full width half maximum (FWHM) of broad Hβ line is nearly 2900km s~(-1) , significantly larger than the customarily adopted criterion of 2000 km s~(-1) . With its weak Fe Ⅱ multiples, we believe that SDSS J143030.22-001115.1 should not be classified as a genuine NLS1. When we calculate the virial black hole masses of NLS1s, we should use the Hβ linewidth after subtracting the NLR component.  相似文献   

CPLD技术及其在现代时统中的应用     

杨蕾  胡永辉 《时间频率学报》2003,26(1):40-47

对CPLD(复杂可编程逻辑器件)技术的基本特征和发展趋势作了简要介绍,揭示了该技术在现代数字系统中的重要地位及作用.利用CPLD对时统设备IRIG-B码产生器进行集成,其实验结果表明,集成了的B码产生器不但简单、可靠,而且便于调试,克服了以往硬件电路复杂的缺点.  相似文献   

应用GPS观测青藏高原东北缘应力场变化   总被引：2，自引：0，他引：2  

张永志  胡斌  陈宏宾 《地球科学与环境学报》2003,25(4):80-84

采用各向同性弹性地球模型推导了地面位移场速率与地壳内任意点应力场变化的边界积分关系,同时利用青藏高原东北缘1999～2001年观测的GPS资料对观测区地壳深度为5 km和25 km的主应力和最大剪应力进行了计算分析.结果表明,青藏高原东北缘的主应力变化主要集中在祁连山断裂、海原断裂等,在1920～1954年间历史上发生过多次震级为7.0～8.5级强震的断裂附近,并具有主应力变化沿断层走向分布、最大剪应力沿断层走向交替变化等特征.  相似文献   

Multistep matched-field inversion for broad-band data from ASIAEX2001     

Kunde Yang Yuanliang Ma Chao Sun Miller  J.H. Potty  G.R. 《Oceanic Engineering, IEEE Journal of》2004,29(4):964-972

This paper discusses the results of geoacoustic inversion carried out using explosive charge data from the Asian Seas International Acoustic Experiment (ASIAEX) East China Sea (ECS) Experiment. A multifrequency incoherent matched-field inversion processor and a genetic algorithm (GA) are used for the inversion. A multistep matched field inversion approach is presented, which makes use of the varying sensitivities of wave fields at various frequencies to reduce the inversion problem into a sequence of smaller inversions with fewer unknowns to estimate at each stage. Different parameters are estimated using data at different frequencies according to their sensitivities. Inversion results for different areas in the ECS region are summarized and compared with core data.  相似文献