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Model test and numerical simulation on the dynamic stability of the bedding rock slope under frequent microseisms

Earthquake Engineering and Engineering Vibration 2020年第4期19卷 919-935页

作者： Deng Zhiyun liu Xinrong liu yongquan liu Shulin Han Yafeng liu Jinhui Tu Yiliang School of Civil Engineering Chongqing UniversityChongqing 400045China National Joint Engineering Research Center for Prevention and Control of Environmental Geological Hazards in the TGR Area Chongqing University Chongqing 400045China China Construction Underground Space Co. Ltd.Chengdu 610081China School of civil engineering Chongqing Jiaotong UniversityChongqing 400074China

Shake table testing was performed to investigate the dynamic stability of a mid-dip bedding rock slope under frequent earthquakes. Then, numerical modelling was established to further study the slope dynamic stability under purely microseisms and the influence of five factors, including seismic amplitude, slope height, slope angle, strata inclination and strata thickness, were considered. The experimental results show that the natural frequency of the slope decreases and damping ratio increases as the earthquake loading times increase. The dynamic strength reduction method is adopted for the stability evaluation of the bedding rock slope in numerical simulation, and the slope stability decreases with the increase of seismic amplitude, increase of slope height, reduction of strata thickness and increase of slope angle. The failure mode of a mid-dip bedding rock slope in the shaking table test is integral slipping along the bedding surface with dipping tensile cracks at the slope rear edge going through the bedding surfaces. In the numerical simulation, the long-term stability of a mid-dip bedding slope is worst under frequent microseisms and the slope is at risk of integral sliding instability, whereas the slope rock mass is more broken than shown in the shaking table test. The research results are of practical significance to better understand the formation mechanism of reservoir landslides and prevent future landslide disasters.

关键词： bedding rock slope frequent microseisms shaking table test numerical simulation dynamic stability failure mode long-term stability

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Precise method to control elastic waves by conformal mapping

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Theoretical & Applied Mechanics Letters 2013年第2期3卷 62-67页

作者： yongquan liu Wei liu Xianyue Su LTCS and Department of Mechanics and Aerospace Engineering College of Engineering Peking University

The transformation method to control waves has received widespread attention in electromagnetism and acoustics. However, this machinery is not directly applicable to the control of elastic waves, because it has been shown that the Navier＇s equation does not usually retain its form under coordinate transformation. In this letter, we prove the form invariance of the Navier＇s equation under the conformal mapping based on the Helmholtz decomposition method. The needed material parameters are provided to manipulate elastic waves. The validity of this approach is confirmed by an active stealth device which can disguise the signal source by changing its position. Experimental verifications and potential applications may be expected in nondestructive testing, structural seismic design and other fields.

关键词： transformation method elastic waves conformal mapping Helmholtz decompositionmethod metamaterials

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Experimental investigation and numerical analysis on high-efficiency shock vectoring control serpentine nozzles

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CHINESE JOURNAL OF AERONAUTICS 2024年第12期37卷 296-324页

作者： Hui, Zhonghao Shi, Jingwei Lin, Wentao Zhou, Li Wang, Zhanxue liu, yongquan Northwestern Polytech Univ Sch Power & Energy Xian 710072 Peoples R China Natl Key Lab Sci & Technol Adv Light Duty Gas Turb Xian 710129 Peoples R China Collaborat Innovat Ctr Adv Aeroengine Beijing 100191 Peoples R China

The high-efficiency Shock Vectoring Control Serpentine Nozzle (SVCSN) takes into account both thrust vectoring and infrared stealth, and significantly improves the comprehensive performance of the aero-engines through an additional auxiliary duct. In this paper, the schlieren photographs at the exit of the high-efficiency SVCSN and the wall static pressure distributions were obtained by experiments, and the numerical results were used to enrich the thrust vectoring characteristics. The effects of the auxiliary injection were analyzed first to reveal the advantages of the high-efficiency SVCSN compared to the conventional SVCSN. Then, the aerodynamic parameters and the structural parameters of the high-efficiency SVCSN were investigated, including the Nozzle Pressure Ratio (NPR), the Secondary flow Pressure Ratio (SPR), the secondary flow relative area and the secondary flow injection angle. Finally, the coupling performance of the high-efficiency SVCSN is studied by using the approximate modeling technology. Results show that the auxiliary injection increases the range between the two shock legs of the "k" shock wave induced by the secondary flow, then causes the separation zone and high-pressure boss of the down wall to expand upstream, and finally results in a prominent increase in the thrust vectoring performance. The thrust vectoring angle and Vectoring Efficiency (VE) of the high-efficiency SVCSN are about 61.6% and 75.7%, respectively, higher than those of the conventional SVCSN at NPR = 6. The effects of the NPR and the SPR on the thrust vectoring performance of the high-efficiency SVCSN are coupled with each other. A larger NPR matched with a smaller SPR shows better thrust vectoring performance. The maximum fluctuations in thrust vectoring angle and VE caused by the NPR and SPRare about 22% and 64%. The VE decreases monotonously with the increase of the secondary flow relative area. Smaller secondary flow injection angle shows better thrust vector performan

关键词： Shock vectoring control Serpentine nozzle Auxiliary injection Thrust vectoring performance Flow control

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The U-Pb chronologic evidence and sedimentary responses of Silurian tectonic activities at northeastern margin of Tarim Basin

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Science China Earth Sciences 2012年第9期55卷 1445-1460页

作者： liu JingYan YANG HaiJun YANG YongHeng CAI ZhenZhong liu yongquan RUI ZhiFeng SU ZhenZhen Ministry of Education's Key Laboratory of Marine Reservoir Evolution and Oil&Gas Accumulation Mechanism China University of GeosciencesBeijing 100083China Institute of Petroleum Exploration and Exploitation Tarim Oil Field CompanyPetroChinaKorla 841000China

U-Pb ages of Devonian detrital zircons from Tabei Uplift have been determined through LA-ICP-MS test *** results revealed that most zircon ages concentrate on 460-414 Ma,especially around 436-423 Ma,indicating possible occurrences of strong tectonic events at the northern margin of Tarim Basin during that *** with previous researches on the basin marginal orogenic belts,intense tectonic activities developed at the northeast margin of Tarim Basin and its obvious sedimentary responses in basin during the end of Ordovician to Early-Middle Silurian are *** include(1) several unconformities within the Late Ordovician-Silurian,showing truncation,erosion,and onlap characteristics,which reflected the local uplift formed during the surrounding extrusion process;(2) the Silurian fluvial delta system from northeast to southwest in Keping,Yingmaili,Hade,and Caohu areas,which reflected the partial uplift at the northeast margin and provided clastic supply to basin;and(3) as indicated by heavy mineral analysis,the Silurian sediments came mainly from the recycles of orogenic belts provenance,which indicated the compress tectonic *** addition,a wide range of red mudstone layer distribution in the upper part of the Silurian may be closely related to the surrounding tectonic uplift and the rapid decline of sea levels.

关键词： detrital zircon U-Pb geochronology tectonic activities Silurian northeastern margin of Tarim Basin

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Effects of Si and Mn Contents on Low-Temperature Toughnes of 10CrSiNiCu Steel

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Journal of Iron and Steel Research International 1999年第1期6卷 43-47页

作者： Yang Caifu, Zhang yongquan, liu Tianjun Central Iron & Steel Research InstituteBeijing100081 钢铁研究总院北京 100081 钢铁研究总院北京

Effects of Si and Mn contents on lowtemperature toughness of 10CrSiNiCu steel were studied in this paper. The results indicated that by properly lowering Si content and increasing Mn content, the strength is increased slightly, and the lowtemperature toughness is improved markedly. When Si content decreased from 096 % to 072 % or 042 mass%, the 50 % FATT dropped by 50 and the crack propagation energy in the process of impact increased obviously. The main reason for the improvement of toughness lies in the refining of grain size and the decreasing of the deteriorative effect of Si.

关键词： content toughness strength crack propagation

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Persistence and Extinction of a Non-Autonomous Plant Disease Model with Roguing<sup>*</sup>

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Journal of Applied Mathematics and Physics 2020年第10期8卷 2197-2212页

作者： Lijun Xia Hengmin Lv Jinxing Yuan yongquan liu Ji’an College Ji’an China

On the basis of analyzing the shortages of present studies on plant disease model for autonomous phenomenon, and considering the actual situation, this paper applies the joint factors of environmental change and the infectivity for latent plants into the system;therefore we deal with a non-autonomous plant disease model with roguing. Some sufficient conditions are established for extinction of diseases and permanence of the system in this paper.

关键词： Non-Autonomous Plant Disease Model Roguing Extinction Permanence

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A Review of the History and Development of Integrated Pest Management(IPM)

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Plant Diseases and Pests 2019年第2期10卷 37-40页

作者： Gong Deping liu yongquan Gong Wenliu Jingzhou Academy of Agricultural Sciences The University of Queensland

The evolvement of IPM has experienced several significant stages. IPM is an ecosystem as a governance unit. It allows the presence of low numbers of pests because a direct or indirect relationship between biological species and their associated environmental living conditions could keep a long-term ecological balance. IPM also emphasizes overall benefits; it is necessary to integrate all kinds of safe, effective, economic, and simple managements as far as possible. When synthesizing and coordinating various managements, effective control object, effective time limit, effective scope, and effective degree of the individual method should be analysed first. The ultimate goal of IPM is for the sustainable development of agriculture. In the future IPM system engineering, crop resistance, the role of natural enemies, agricultural control, and the application of biological control technologies will be greatly strengthened, and the role of chemical pesticides will be significantly reduced. Safe, effective, and long-lasting control of pest populations will be below the level of harm caused, which could protect the ecological environment and the health of people and livestock, and promote the development of production.

关键词： Integrated Pest Management (IPM) Development process Agro-ecology Environmental protection Development progress

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Metformin ameliorates insulin resistance in L6 rat skeletal muscle cells through upregulation of SIRT3

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Chinese Medical Journal 2014年第8期127卷 1523-1529页

作者： Song Yuping Shi Jingli Wu Ying Hart Chong Zou Junjie Shi yongquan liu Zhimin Department of Endocrinology Changzheng Hospital Second Military Medical University Shanghai 200003 China

Background SIRT3 is an important regulator in cell metabolism, and recent studies have shown that it may be involved in the pharmacological effects of metformin. However, the molecular mechanisms underlying this process are unclear. Methods The effects of SIRT3 on the regulation of oxidative stress and insulin resistance in skeletal muscle were evaluated in vitro. Differentiated L6 skeletal muscle cells were treated with 750 pmol/L palmitic acid to induce insulin resistance. SIRT3 was knocked down and overexpressed in L6 cells. SIRT3, nuclear factor kappa-light-chain-enhancer of activated B cells （NF-KB） p65, c-Jun N-terminal kinase 1 （JNK1）, and superoxide dismutase 2 （SOD2） were evaluated by Western blotting. Results Over expression of SIRT3 increased glucose uptake and decreased ROS production in L6-1R cells as well as in L6 cells. Knock-down of SIRT3 induced increased production of ROS while decreased glucose uptake in both L6 and L6- IR cells, and these effects were reversed by N-acetyI-L-cysteine （NAC）. Metformin increased the expression of SIRT3 （1.5- fold） and SOD2 （2-fold） while down regulating NF-KB p65 （1.5-fold） and JNK1 （1.5-fold）. Knockdown of SIRT3 （P〈0.05） reversed the metformin-induced decreases in NF-KB p65 and JNK1 and the metformin-induced increase in SOD2 （P〈0.05）. Conclusions Upregulated SIRT3 is involved in the pharmacological mechanism by which metformin promotes glucose uptake. Additionally, SIRT3 may function as an important regulator of oxidative stress and a new alternative approach for targeting insulin resistance-related diseases.

关键词： metformin SIRT3 insulin resistance oxidative stress nuclear factor-kB p65

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航空发动机风扇/压气机技术发展的若干问题与思考

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航空学报 2015年第8期36卷 2563-2576页

作者：刘永泉刘太秋季路成中航工业沈阳发动机设计研究所沈阳110015 北京理工大学宇航学院北京100081

未来10~20年我国航空发动机科技将迎来千载难逢的发展机遇,必须做好充分准备。以航空发动机核心部件——风扇/压气机气动领域为重点,首先,从设计方法、理论、设计性能指标发展以及气动力学仍存在的疑问角度出发,梳理了其国际发展态势;随... 详细信息

未来10~20年我国航空发动机科技将迎来千载难逢的发展机遇,必须做好充分准备。以航空发动机核心部件——风扇/压气机气动领域为重点,首先,从设计方法、理论、设计性能指标发展以及气动力学仍存在的疑问角度出发,梳理了其国际发展态势;随后,针对基础研究、创新能力等方面,阐述国内发展现状与存在的问题;最后,分析给出关于风扇/压气机后续发展的方向、思路和重点,力求为我国军民航空发动机风扇/压气机的技术研制思路提供参考。

关键词：发动机风扇压气机技术研究技术体系发展态势

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“大学英语B”移动学习实证研究——基于FRAME模型的设计与开发

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开放教育研究 2012年第3期18卷 76-82页

作者：刘永权北京广播电视大学理工教学部北京100081

随着信息技术的发展,移动学习越来越受到各级各类教育和培训机构的青睐。众多机构和院校纷纷设立项目开展研究,但这些研究要么尚局限于大学的普适技术实验室,要么在学校中被看作是课堂学习的补充,即使是在电大系统中也大多当作信息交流... 详细信息

随着信息技术的发展,移动学习越来越受到各级各类教育和培训机构的青睐。众多机构和院校纷纷设立项目开展研究,但这些研究要么尚局限于大学的普适技术实验室,要么在学校中被看作是课堂学习的补充,即使是在电大系统中也大多当作信息交流和日常管理的平台。本研究以电大系统广泛采用的蓝卓校园网为平台,以北京广播电视大学五所分校的100名本科学生为研究对象,采用手机彩信(MMS)方式为试点学生发送教育部统考"大学英语B"微型课件。本研究以FRAME移动学习分析模型为出发点,在实验前期对学习对象、教学设计、内容呈现等方面做了充分调研。经过一个学期的试点后,从实验效果、学习者认可度和对下一步实验的意见、建议等方面实施了调查问卷和访谈。研究结果表明,与控制组学生相比,实验组学生考试通过率大幅度提升,绝大部分成人学习者对这种学习方式持欢迎态度,并对扩大试点范围和内容针对性等方面提出了建议。由于该研究是基于教学实践的实证研究,将对以后移动学习的普及乃至泛在学习的未来发展提供案例参考。

关键词： “大学英语B” 移动学习 FRAME模型

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