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Path Planning in Complex 3D Environments Using a Probabilistic Roadmap Method

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International Journal of Automation and computing 2013年第6期10卷 525-533页

作者： Fei Yan Yi-sha liu Ji-Zhong Xiao School of Control Science and Engineering Dalian University of Technology School of Information Science and Technology Dalian Maritime University Department of Electrical and Engineering The City CollegeCity University of New York

This paper presents a 3D path planning algorithm for an unmanned aerial vehicle （UAV） in complex environments. In this algorithm, the environments are divided into voxels by octree algorithm. In order to satisfy the safety requirement of the UAV, free space is represented by free voxels, which have enough space margin for the UAV to pass through. A bounding box array is created in the whole 3D space to evaluate the free voxel connectivity. The probabilistic roadmap method （PRM） is improved by random sampling in the bounding box array to ensure a more efficient distribution of roadmap nodes in 3D space. According to the connectivity evaluation, the roadmap is used to plan a feasible path by using A＊ algorithm. Experimental results indicate that the proposed algorithm is valid in complex 3D environments.

关键词： 3D path planning complex environment unmanned aerial vehicle (UAV) probabilistic roadmap methed (PRM) octree.

Cellular automata simulation of grain growth of powder metallurgy Ni-based superalloy

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Journal of Iron and Steel Research International 2023年第4期30卷 838-848页

作者： Yi-ling Jiang sha-sha liu Rong-gui Lu Xu Cheng Jia Li Yang Chen Gao-feng Tian School of Materials Science and Engineering Beihang UniversityBeijing 100191China National Engineering Laboratory of Additive Manufacturing for Large Metallic Components Beijing 100191China Beijing Institute of Aeronautical Materials Beijing 100095China

Primary γ'phase instead of carbides and borides plays an important role in suppressing grain growth during solution at 1433 K of Ni-based FGH98 *** illustrate that as-fabricated FGH98 superalloy has equiaxed grain structure,and after heat treatment,grains remain equiaxed but grow *** order to clarify the effects of the size and volume fraction of the primaryγ'phase on the grain growth during heat treatment,a 2D cellular automata(CA)model was established based on the thermal activation and the lowest energy *** CA results are compared with the experimental results and show a good fit with an error less than 10%.Grain growth kinetics are depicted,and simulations in real time for various sizes and volume fractions of primaryγ'particles work out well with the Zener *** coefficient n value which reflects the pinning ability in Zener relation is theoretically calculated,and its minimum value is 0.23 when the radius of primaryγ'phase is 2.8μm.

关键词： Grain growth Cellular automata Ni-based FGH98 superalloy Primary γ'phase Microstructure

Shear wave splitting analysis of local earthquakes from dense arrays in Shimian,Sichuan

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Earthquake Science 2023年第1期36卷 52-63页

作者： sha liu Baofeng Tian Institute of Geophysics China Earthquake AdministrationBeijing 100081China

The Shimian area of Sichuan sits at the junction of the Bayan Har ***-Yunnan rhombic block,and Yangtze block,where several faults *** region features intense tectonic activity and frequent *** this study,we used local seismic waveform data recorded using dense arrays deployed in the Shimian area to obtain the shear wave splitting parameters at 55 seismic stations and thereby determine the crustal anisotropic characteristics of the *** then analyzed the crustal stress pattern and tectonic setting and explored their relationship in the study *** some stations returned a polarization direction of NNW-SSE.a dominant polarization direction of NW-SE was obtained for the fast shear wave at most seismic stations in the study *** polarization directions of the fast shear wave were highly consistent throughout the *** orientation was in accordance with the direction of the regional principal compressive stress and parallel to the trend of the Xianshuihe and Daliangshan *** distribution of crustal anisotropy in this area was affected by the regional tectonic stress field and the fault *** mean delay time between fast and slow shear waves was 3.83 ms/*** greater than the values obtained in other regions of *** indicates that the crustal media in our study area had a high anisotropic strength and also reveals the influence of tectonic complexity resulting from the intersection of multiple faults on the strength of seismic anisotropy.

关键词： shear wave splitting polarization direction of the fast shear wave regional principal compressive stress dense array Citation:liu S and Tian BF(2023).Shear wave splitting analysis of local earthquakes from dense arrays in Shimian,Sichuan.

A new ceramide from transgenic crown galls of Panax quinquefolium

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Chinese Chemical Letters 2009年第4期20卷 447-449页

作者： Jian Hua Zhu sha liu Rong Min Yu College of Pharmacy Jinan University Guangzhou 510632 China

A new ceramide （1） was isolated from transgenic crown galls of Panax quinquefolium. The structure was elucidated as （2S, 3S, 4R, 20E）-2-[（2＇R）-2＇-hydroxylpalmitoylamino]-20-hexacosene- 1, 3, 4-triol on the bas... 详细信息

关键词： Transgenic crown galls Panax quinquefolium Ceramide

Acid-sensing ion channels: potential therapeutic targets for neurologic diseases

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Translational Neurodegeneration 2015年第1期4卷 68-75页

作者： sha liu Xiao-Yu Cheng Fen Wang Chun-Feng liu Department of Neurology the Second Affiliated Hospital of Soochow UniversitySoochow University1055 Sanxiang RoadSuzhou 215004China Institute of Neuroscience Soochow UniversitySuzhou 215123China Beijing Key Laboratory for Parkinson’s Disease Beijing 100053China

Maintaining the physiological pH of interstitial fluid is crucial for normal cellular *** disease states,tissue acidosis is a common pathologic change causing abnormal activation of acid-sensing ion channels(ASICs),which according to cumulative evidence,significantly contributes to inflammation,mitochondrial dysfunction,and other pathologic mechanisms(i.e.,pain,stroke,and psychiatric conditions).Thus,it has become increasingly clear that ASICs are critical in the progression of neurologic *** review is focused on the importance of ASICs as potential therapeutic targets in combating neurologic diseases.

关键词： Acid sensing ionic channels Neurologic diseases Pathophysiology Neurodegeneration

Pseudopotential-based discrete unified gas kinetic scheme for modeling multiphase fluid flows

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Advances in Aerodynamics 2022年第1期4卷 662-687页

作者： Zeren Yang sha liu Congshan Zhuo Chengwen Zhong School of Aeronautics Northwestern Polytechnical University127 West Youyi Road710072Xi’anChina National Key Laboratory of Science and Technology on Aerodynamic Design and Research Northwestern Polytechnical University127 West Youyi Road710072Xi’anChina

To directly incorporate the intermolecular interaction effects into the discrete unified gas-kinetic scheme(DUGKS)for simulations of multiphase fluid flow,we developed a pseudopotential-based DUGKS by coupling the pseudopotential model that mimics the intermolecular interaction into *** to the flux reconstruction procedure,additional terms that break the isotropic requirements of the pseudopotential model will be *** eliminate the influences of nonisotropic terms,the expression of equilibrium distribution functions is reformulated in a moment-based *** the isotropy-preserving parameter appropriately tuned,the nonisotropic effects can be properly canceled *** fundamental capabilities are validated by the flat interface test and the quiescent droplet *** has been proved that the proposed pseudopotential-based DUGKS managed to produce and maintain isotropic *** isotropy-preserving property of pseudopotential-based DUGKS in transient conditions is further confirmed by the spinodal *** superiority of the pseudopotential-based DUGKS over the lattice Boltzmann method is also demonstrated by predicting the coexistence densities complying with the van der Waals equation of *** directly incorporating the intermolecular interactions,the pseudopotential-based DUGKS offers a mesoscopic perspective of understanding multiphase behaviors,which could help gain fresh insights into multiphase fluid flow.

关键词： Pseudopotential model Discrete unified gas kinetic scheme Multiphase flows Isotropic interface

Electrochemical behavior of microbiologically influenced corrosion on Fe_3Al in marine environment

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Acta Metallurgica Sinica(English Letters) 2009年第4期22卷 313-320页

作者： Xueting CHANG Shougang CHEN Guanhui GAO Yansheng YIN sha CHENG Tao liu Institute of Materials Science and Technology Ocean University of China Qingdao 266100 China

In this article, microbiologically influenced corrosion behavior of Fe3Al intermetallie compound in microorganism culture medium has been investigated by using weight loss methods, electrochemical techniques, and electron microscopy. Polarization curves showed that a sharp electrical current peak caused by surface pitting could be observed after Fe3Al electrodes were immersed in culture medium for 15 days when the polarization potential was about -790 mV vs SCE. Based on the electrochemical impedance spectroscopy （EIS） and the equivalent circuit parameters of the associated system, the corrosion products were found to exhibit a two-layer structured feature and the microorganisms could induce pitting and erosion corrosion of the inner layer. In addition, the passivating film of the inner layer was absolutely destroyed by microbial metabolic products.

关键词： Electrochemical behavior Fe3Al Microbiologically influenced corrosion Marine

Cancer-associated fibroblasts in digestive tumors

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World Journal of Gastroenterology 2014年第47期20卷 17804-17818页

作者： Lei Huang A-Man Xu sha liu Wei liu Tuan-Jie Li Department of Gastrointestinal Surgery The First Affiliated Hospital of Anhui Medical University Guangdong Provincial Key Laboratory of Liver Disease Research the Third Affiliated Hospital of Sun Yat-sen University Department of Medical Oncology the First Affiliated Hospital of Anhui Medical University Liver Transplantation Center the Third Affiliated Hospital of Sun Yat-sen University

The significant influence of tumor stroma on malignant cells has been extensively investigated in this era of targeted therapy. The tumor microenvironment, as a dynamic system, is orchestrated by various cells including tumor vascular composing cells, inflammatory cells and fibroblasts. As a major and important component in tumor stroma, increasing evidence has shown that spindle-shaped cancer-associated fibroblasts (CAFs) are a significant modifier of cancer evolution, and promote tumorigenesis, tumor invasion and metastasis by stimulating angiogenesis, malignant cell survival, epithelial-mesenchymal transition (EMT) and proliferation via direct cell-to-cell contact or secretion of soluble factors in most digestive solid tumors. CAFs are thought to be activated, characterized by the expression of α-smooth muscle actin, fibroblast activated protein, fibroblast specific protein, vimentin, fibronectin, etc. They are hypothesized to originate from normal or aged fibroblasts, bone marrow-derived mesenchymal cells, or vascular endothelial cells. EMT may also be an important process generating CAFs, and most probably, CAFs may originate from multiple cells. A close link exists between EMT, tumor stem cells, and chemo-resistance of tumor cells, which is largely orchestrated by CAFs. CAFs significantly induce immunosuppression, and may be a prognostic marker in various malignancies. Targeted therapy toward CAFs has displayed promising anticancer efficacy, which further reinforces the necessity to explore the relationship between CAFs and their hosts.

关键词： Cancer-associated fibroblast Tumor progression Epithelial-mesenchymal transition Tumor immunity Targeted therapy

Teaching of pathophysiology combined with clinical practice in the 21st century

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中国病理生理杂志 2009年第11期25卷 2249-2250页

作者： HAN Li- sha liu Jia Department of Pathophysiology Baotou Medical College Baotou 014060 China

Pathophysiology,dealing with the functional changes in the host with disease or particular syndrome,is regarded as a bridge to guide students from basic medicine to clinical medicine. However,the traditional way in teaching of pathophysiology is far from clinical practice,mainly focuses on the acquisition and mastery of theoretical knowledge. Moreover,it is difficult for students to master the basic theoretical knowledge specifically and effectively under the condition away from clinical patients. In order to enhance the association of basic course with clinic,to combine the lecture and learning knowledge and clinical skills,we try to perform the combination of teaching pathophysiology with clinical practice in the training program for teachers and teaching activities. 1. The object:(1)Based on typical clinical cases,students participate bed side teaching and study theoretical knowledge.(2)To create whole concept on association among organs and systems of human diseases.

关键词：病理生理学生理学教学临床实践临床医学基础医学传统方法综合征