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Mechanism underlying the uprooting of taproot-type shrub species in the loess area of northeastern Qinghai-Xizang Plateau, China
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作者 LIANG Shen WANG Shu +4 位作者 LIU Yabin PANG Jinghao ZHU Haili LI Guorong HU Xiasong 《Journal of Arid Land》 SCIE CSCD 2024年第10期1426-1443,共18页
Characteristics of root pullout resistance determine the capacity to withstand uprooting and the slope protection ability of plants.However,mechanism underlying the uprooting of taproot-type shrub species in the loess... Characteristics of root pullout resistance determine the capacity to withstand uprooting and the slope protection ability of plants.However,mechanism underlying the uprooting of taproot-type shrub species in the loess area of northeastern Qinghai-Xizang Plateau,China remains unclear.In this study,a common taproot-type shrub,Caragana korshinskii Kom.,in northeastern Qinghai-Xizang Plateau was selected as the research material.Mechanism of root-soil interaction of vertical root of C.korshinskii was investigated via a combination of a single-root pullout test and numerical simulation analysis.The results indicated that,when pulling vertically,axial force of the roots decreased with an increase in buried depth,whereas shear stress at root-soil interface initially increased and then decreased as burial depths increased.At the same buried depth,both axial force and shear stress of the roots increased with the increase in pullout force.Shear stress and plastic zone of the soil surrounding the root were symmetrically distributed along the root system.Plastic zone was located close to the surface and was caused primarily by tensile failure.In nonvertical pulling,symmetry of shear stress and plastic zone of the soil surrounding the root was disrupted.We observed larger shear stress and plastic zones on the side facing the direction of root deflection.Plastic zone included both shear and tensile failure.Axial force of the root system near the surface decreased as deflection angle of the pullout force increased.When different rainfall infiltration depths had the same vertical pulling force,root axial force decreased with the increase of rainfall infiltration depth and total root displacement increased.During rainfall infiltration,shear stress and plastic zone of the soil surrounding the root were prone to propagating deeper into the soil.These findings provide a foundation for further investigation of soil reinforcement and slope protection mechanisms of taproot-type shrub species in the loess area of northeastern Qinghai-Xizang Plateau and similar areas. 展开更多
关键词 Qinghai-Xizang Plateau shrub roots pullout test numerical simulation MECHANISM root-soil interaction
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A ROOT-based detector test system 被引量:4
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作者 Huang-Kai Wu Chen Li 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2021年第10期50-58,共9页
Most detectors for nuclear physics experiments are detector arrays composed of numerous units.Testing each detector unit is a major part of the research work on detector arrays.To save time and simplify the research p... Most detectors for nuclear physics experiments are detector arrays composed of numerous units.Testing each detector unit is a major part of the research work on detector arrays.To save time and simplify the research process,a ROOT-based detector test system was designed for detector unit testing.The test system is a general pur-pose and expandable software system that can support most of the hardware devices in the market.Users can easily build a complete detector test system using the required hardware devices.The software is based on the ROOT framework and is operated on the Linux platform.The software of the test system consists of four parts:the controller,data acquisition(DAQ),high-voltage power supply,and online monitoring and analysis.In addition,a user-friendly graphical user interface(GUI)was designed for user convenience.Moreover,the online analysis func-tion of the software can implement automatic peak searching and spectrum fitting for different radioactive sources,and the results under different conditions can be shown automatically.The completion of the test system could greatly simplify the development process of the detector. 展开更多
关键词 Detector test Data analysis root
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Modeling Methods and Test Verification of Root Insert Contact Interface for Wind Turbine Blade 被引量:1
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作者 Li Hui Wang Tongguang 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2016年第1期9-15,共7页
Two modeling methods of the root insert for wind turbine blade are presented,i.e.,the local mesh optimization method(LMOM)and the global modeling method(GMM).Based on the optimized mesh of the local model for the meta... Two modeling methods of the root insert for wind turbine blade are presented,i.e.,the local mesh optimization method(LMOM)and the global modeling method(GMM).Based on the optimized mesh of the local model for the metal contact interface,LMOM is proposed to analyze the load path and stress distribution characteristics,while GMM is used to calculate and analyze the stress distribution characteristics of the resin layer established between the bushing and composite layers of root insert.To validate the GMM,a tension test is carried out.The result successfully shows that the shear strain expresses a similar strain distribution tendency with the GMM′s results. 展开更多
关键词 root insert modeling methods mesh optimization contact interface tension test
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A note on self-normalized Dickey-Fuller test for unit root in autoregressive time series with GARCH errors 被引量:1
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作者 YANG Xiao-rong ZHANG Li-xin 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2008年第2期197-201,共5页
In this article, the unit root test for AR(p) model with GARCH errors is considered. The Dickey-Fuller test statistics are rewritten in the form of self-normalized sums, and the asymptotic distribution of the test s... In this article, the unit root test for AR(p) model with GARCH errors is considered. The Dickey-Fuller test statistics are rewritten in the form of self-normalized sums, and the asymptotic distribution of the test statistics is derived under the weak conditions. 展开更多
关键词 unit root AR (p)-GARCH (1 1) SELF-NORMALIZED Dickey-Fuller test statistic.
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Optimization of Factors Influencing Adventitious Rooting in Hybrid Larch
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作者 Kuipeng Li Hua Han +1 位作者 Yunhui Xie Xiaomei Sun 《Phyton-International Journal of Experimental Botany》 SCIE 2021年第2期583-593,共11页
Optimization of in vitro adventitious root induction contributes to the development of a large-scale production system of hybrid clone seedlings of larch(Larix spp.).We used orthogonal testing to investigate the facto... Optimization of in vitro adventitious root induction contributes to the development of a large-scale production system of hybrid clone seedlings of larch(Larix spp.).We used orthogonal testing to investigate the factors that affect the rooting of hybrid larch shoots-activated carbon,vitamin B1,sucrose,glycine,glutamic acid(Glu),cysteine,pH,and induction time in the dark and indole-3-butyric acid(IBA).Variance analysis showed that the effects of sucrose concentration on rooting rate,survival rate,and average root number,pH on the average number of roots;and Glu on survival rate were all significant(p<0.05)when compared to the mock treatments.Among all of the 45 treatments,the highest rooting rate was 90%,the highest survival rate was 100%,and the highest average root number was 11.8.The theoretically optimal procedure of in vitro root induction of hybrid larch shoots is shoot induction on L9 modified medium(pH 6.7)containing 2 mg.L^(-1)naphthalene acetic acid,0.25 mg.L^(-1)IBA,1/3 macroelements,7.5 g.L^(-1)sucrose,and 5 mg.L^(-1)Glu for 8 days,and then root induction on L9 modified medium without auxin. 展开更多
关键词 Hybrid larch adventitious root orthogonal test variance analysis
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Is There Hysteresis in Unemployment in OECD Countries? Evidence From Panel Unit Root Test With Structural Breaks
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作者 Meliha Ener Feyza Ariea 《Chinese Business Review》 2011年第4期294-304,共11页
This study tests the hysteresis hypothesis of unemployment in fifteen OECD countries by using panel unit root tests which allow for structural breaks. We apply annual unemployment rates covering 1985-2008 periods. We ... This study tests the hysteresis hypothesis of unemployment in fifteen OECD countries by using panel unit root tests which allow for structural breaks. We apply annual unemployment rates covering 1985-2008 periods. We test whether unemployment rates are stationary by using second generation tests which allow cross section dependency among series and panel unit root test based on structural break advanced by Carrion-i-Silvestre, Barrio-Castro and Lopez-Bazo (2005). We find series as a stationary process with structural breaks according to Carrion-i Silvestre et al. (2005) test, while we find series as unit root process with second generation panel unit root test. According to the Carrion-i Silvestre et al. (2005) test, we find the evidence of absence of hysteresis in analyzed countries. As a result, temporary shocks have temporary effects on unemployment instead of permanent effect. Structural factors can affect the natural rate of unemployment and, therefore, unemployment would be stationary around a process that is subject to structural breaks. So, there still exists a unique natural rate of unemployment to which the economy eventually will converge. 展开更多
关键词 structural break UNEMPLOYMENT cross-section dependence panel unit root tests
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A RPC test station based on ROOT and VME
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作者 Zhi-Peng Lu Qing-Min Zhang +7 位作者 Jie Zhao Jia-Wen Zhang Yu-Guang Xie Sen Qian Zhe Ning Jeremiah Monari Kebwaro Yu-Chi Chen Zi-Xing He 《Nuclear Science and Techniques》 SCIE CAS CSCD 2016年第2期79-85,共7页
Due to its advantages in large-area application situations, the R&D of the resistive plate chamber(RPC)has always been carried out. A performance test station for RPC R&D has been designed and developed based ... Due to its advantages in large-area application situations, the R&D of the resistive plate chamber(RPC)has always been carried out. A performance test station for RPC R&D has been designed and developed based on the VME bus and ROOT in Linux. This system can be customized expediently according to the requirements of different tests, which facilitates detector R&D because of its automatic HV scan, especially for long-term test. With this system, we have implemented the RPC performance test,including the efficiency curve, counting rate, dark current and charge and timing resolution. 展开更多
关键词 VME总线 RPC 试验站 Linux 性能试验台 时间分辨率 长期试验 性能测试
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Biomechanical behavior of grass roots at different gauge lengths
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作者 FU Jiangtao ZHOU Zhe +4 位作者 GUO Hong ZHAO Jimei YU Dongmei WU Jie HU Xiasong 《Journal of Mountain Science》 SCIE CSCD 2024年第9期3201-3214,共14页
Gauge length influences the biomechanical properties of herbaceous roots such as tensile resistance,tensile strength and Young’s modulus.However,the extent to which and how these biomechanical properties of herbaceou... Gauge length influences the biomechanical properties of herbaceous roots such as tensile resistance,tensile strength and Young’s modulus.However,the extent to which and how these biomechanical properties of herbaceous roots are influenced remain unknown.To better understand the behavior of roots in tension under different conditions and to illustrate these behaviors,uniaxial tensile tests were conducted on the Poa araratica roots as the gauge length increased from 20 mm to 80 mm.Subsequently,ANOVA was used to test the impact of the significant influences of gauge length on the biomechanical properties,nonlinear regression was applied to establish the variation in the biomechanical properties with gauge length to answer the question of the extent to which the biomechanical properties are influenced,and Weibull models were subsequently introduced to illustrate how the biomechanical properties are influenced by gauge length.The results reveal that(1)the variation in biomechanical properties with root diameter depends on both the gauge length and the properties themselves;(2)the gauge length significantly impacts most of the biomechanical properties;(3)the tensile resistance,tensile strength,and tensile strain at cracks decrease as the gauge length increases,with values decreasing by 20%-300%,while Young’s modulus exhibits the opposite trend,with a corresponding increase of 30%;and(4)the Weibull distribution is suitable for describing the probability distribution of these biomechanical properties;the Weibull modulus for both tensile resistance and tensile strain at cracks linearly decrease with gauge length,whereas those for tensile strength and Young’s modulus exhibit the opposite trend.The tensile resistance,tensile strength,and tensile strain at the cracks linearly decrease with increasing gauge length,while the tensile strength and Young’s modulus linearly increase with increasing gauge length. 展开更多
关键词 Biomechanical properties of roots Weibull distribution ANOVA Uniaxial tensile test Linear regression
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17~45岁肥胖门诊患者的6分钟步行试验距离参考方程研究
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作者 张家鸣 王欣宇 +1 位作者 王道荣 孙晓芳 《中国全科医学》 CAS 北大核心 2025年第3期330-334,345,共6页
背景 目前6分钟步行试验(6MWT)已经被广泛用于评估肥胖人群的运动能力,并为制订干预措施提供了参考依据。国外已有研究提出了其他人群的6MWT距离参考方程,但中国17~45岁且BMI≥30 kg/m^(2)肥胖受试者的6MWT距离参考方程研究较少。目的 ... 背景 目前6分钟步行试验(6MWT)已经被广泛用于评估肥胖人群的运动能力,并为制订干预措施提供了参考依据。国外已有研究提出了其他人群的6MWT距离参考方程,但中国17~45岁且BMI≥30 kg/m^(2)肥胖受试者的6MWT距离参考方程研究较少。目的 为17~45岁门诊肥胖受试者制订6MWT距离参考方程,并评估其影响因素。方法 根据美国胸科学会指南,前瞻性选取2022年6月—2023年9月于江苏省苏北人民医院内分泌科肥胖门诊部就诊的143名年龄17~45岁且BMI≥30 kg/m^(2)的成年人(71名男性和72名女性),进行人体测量和6MWT。采用逐步多元回归模型建立6MWT距离参考方程,将新建立的6MWT距离参考方程与现有的预测方程进行比较。结果 143名受试者的平均6MWT距离为(506.1±49.8)m,其中男性平均6MWT距离为(515.7±50.1)m,大于女性的平均6MWT距离(496.6±47.9)m(P<0.05)。在年龄段17~23岁、24~30岁、31~37岁以及38~45岁中,男性与女性6MWT距离比较,差异均有统计学意义(P<0.05)。男性受试者的体质量、BMI、最大心率(HR_(max))、心率差(ΔHR)、腰围、舒张压差(ΔDBP)、Borg量表评分差(ΔBorg)与6MWT距离相关(P<0.05),女性受试者的体质量、BMI、腰围与6MWT距离相关(P<0.05)。以步进的方法将潜在的影响因素纳入多元线性回归方程中,最终建立6MWT距离参考公式:男性y=494.463+1.414×ΔHR-3.903×BMI+0.874×HR_(max),R^(2)=0.429,女性y=670.448+0.299×ΔHR-4.342×BMI-0.195×HR_(max),R^(2)=0.312。结论 17~45岁门诊肥胖受试者中,男性的平均6MWT距离长于女性,且在不同年龄段均有显著差异。男性的体质量、BMI、HR_(max)、ΔHR、腰围、ΔDBP、ΔBorg与6MWT距离相关,女性的体质量、BMI、腰围、ΔSBP与6MWT距离相关。通过多元线性回归分析,为男性和女性分别建立了预测6MWT距离的参考方程,这些公式可能为评估个体的体能水平提供有价值的参考。 展开更多
关键词 肥胖症 步行试验 距离方程 17~45岁 6分钟步行试验 影响因素分析
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Delay-dependent stability and added damping of SDOF real-time dynamic hybrid testing 被引量:14
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作者 Chi Fudong Wang Jinting Jin Feng 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2010年第3期425-438,共14页
It is well-recognized that a transfer system response delay that reduces the test stability inevitably exists in real-time dynamic hybrid testing (RTDHT). This paper focuses on the delay-dependent stability and adde... It is well-recognized that a transfer system response delay that reduces the test stability inevitably exists in real-time dynamic hybrid testing (RTDHT). This paper focuses on the delay-dependent stability and added damping of SDOF systems in RTDHT. The exponential delay term is transferred into a rational fraction by the Pad6 approximation, and the delay-dependent stability conditions and instability mechanism of SDOF RTDHT systems are investigated by the root locus technique. First, the stability conditions are discussed separately for the cases of stiffness, mass, and damping experimental substructure. The use of root locus plots shows that the added damping effect and instability mechanism for mass are different from those for stiffness. For the stiffness experimental substructure case, the instability results from the inherent mode because of an obvious negative damping effect of the delay. For the mass case, the delay introduces an equivalent positive damping into the inherent mode, and instability occurs at an added high frequency mode. Then, the compound stability condition is investigated for a general case and the results show that the mass ratio may have both upper and lower limits to remain stable. Finally, a high-emulational virtual shaking table model is built to validate the stability conclusions. 展开更多
关键词 real-time dynamic hybrid testing root locus analysis delay-dependent stability Pade approximation added damping
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Anchorage properties at the interface between soil and roots with branches 被引量:7
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作者 Xiaodong Ji Lihua Chen Ao Zhang 《Journal of Forestry Research》 SCIE CAS CSCD 2017年第1期83-93,共11页
Roots play an important role in stabilizing and strengthening soil. This article aims to study the mechanical properties of the interface between soil and roots with branches, using the pullout test method in the labo... Roots play an important role in stabilizing and strengthening soil. This article aims to study the mechanical properties of the interface between soil and roots with branches, using the pullout test method in the laboratory. The mechanical properties of the soil-root with branches interface is determined through the pullout-force and root-slippage curve (F-S curve). The results of investigating 24 Pinus tabulaeformis single roots and 55 P. tabulaeformis roots with branches demonstrated three kinds of pullout test failures: breakage failure on branching root, breakage failure on branching node, and pullout failure. The branch angle had a remarkable effect on the failure mode of the roots with branches: the maximum pullout force increased with the sum of the branch diameters and the branch angle. The peak slippage and the initial force had a positive correlation with the sum of the branch diameter. The sig- nificance test of correlation between branch angle and the initial force, however, showed they had no correlation. Branch angle and branch root diameter affect the anchorage properties between root system and soil. Therefore, it is important to investigate the anchorage mechanics of the roots with branches to understand the mechanism of root reinforcement and anchorage. 展开更多
关键词 root-soil interface mechanics Pullout test method root branches Branch angle
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Influence of soil moisture content on pullout properties of Hippophae rhamnoides Linn. roots 被引量:7
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作者 ZHANG Chao-bo LIU Ya-ting +1 位作者 LI Dong-rong JIANG Jing 《Journal of Mountain Science》 SCIE CSCD 2020年第11期2816-2826,共11页
Plant root system plays an important role in preventing soil erosion and improving slope stability.However,its performance is significantly affected by soil moisture content,and the role of soil moisture in root reinf... Plant root system plays an important role in preventing soil erosion and improving slope stability.However,its performance is significantly affected by soil moisture content,and the role of soil moisture in root reinforcement is not fully understood.In this study,the influence of soil moisture on root pullout properties was studied by experiments.Vertical in-situ pullout tests under four different levels of soil matric suction(12 kPa,18 kPa,24 kPa,30 kPa)were carried out on roots of sea buckthorn plants(Hippophae rhamnoides Linn.)which were artificially cultivated for 7 months.Diameter and length of the root system of sea buckthorn were investigated.The results showed that a very significant correlation was observed between root diameter(D)and root length(L)(P<0.01),and root diameter decreased with soil depth.When soil bulk density was constant,peak pullout force(F)and friction coefficient of root-soil interface(μ)decreased with increasing gravimetric soil moisture content in power functions.Soil moisture content significantly affected root pullout resistance because the increase of soil moisture content decreased the friction coefficient between the roots and soil.Root diameter at breakage point(Db)and length of root segment left in soil(Lb)were increased with soil moisture content.In addition,peak pullout force of the roots increased in a power function with root diameter at the soil surface(D0)and in a linear function with total root length(L).The results provided an experimental basis for quantifying the effects of soil moisture content on soil reinforcement by plant roots. 展开更多
关键词 Soil moisture content Peak pullout force root pullout tests root reinforcement root morphology Hippophae rhamnoides Linn
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Application of bi-directional static loading test to deep foundations 被引量:4
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作者 Guoliang Dai Weiming Gong 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE 2012年第3期269-275,共7页
Bi-directional static loading test adopting load cells is widely used around the world at present, with increase in diameter and length of deep foundations. In this paper, a new simple conversion method to predict the... Bi-directional static loading test adopting load cells is widely used around the world at present, with increase in diameter and length of deep foundations. In this paper, a new simple conversion method to predict the equivalent pile head load-settlement curve considering elastic shortening of deep foundation was put forward according to the load transfer mechanism. The proposed conversion method was applied to root caisson foundation in a bridge and to large diameter pipe piles in a sea wind power plant. Some new load cells, test procedure, and construction technology were adopted based on the applications to different deep foundations, which could enlarge the application scopes of bi-directional loading test. A new type of bi-directional loading test for pipe pile was conducted, in which the load cell was installed and loaded after the pipe pile with special connector has been set up. Unlike the conventional bi-directional loading test, the load cell can be reused and shows an evident economic benefit. 展开更多
关键词 deep foundations bi-directional static loading test root caisson foundation large diameter pipe pile
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Evaluation of Cytogenetic Effects of Isoproturon on the Root Meristem Cells of Allium sativum 被引量:3
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作者 L. K. S. CHAUHAN, P. N. SAXENA, AND S. K. GUPTA1Cell Biology Section, Industrial Toxicology Research Centre, P. B. No. 80, M. G. Marg, Lucknow- 226001, India\ \ 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2001年第3期214-219,共6页
Objective\ To validate the use of Allium sativum as a reliable test model for genotoxicity, isoproturon, a substituted phenylalkylurea herbicide, was evaluated on the root meristem cells by this plant system. M... Objective\ To validate the use of Allium sativum as a reliable test model for genotoxicity, isoproturon, a substituted phenylalkylurea herbicide, was evaluated on the root meristem cells by this plant system. Method\ Test concentrations were selected by determining EC50 and root tips were exposed to various concentrations for 6 or 24 hr. EC50 concentration was calculated to be 70.8 ppm for the root growth. In addition to root growth retardation exposure to isoproturon induced morpholoogical changes like discolouration and stiffness of roots. Results\ Exposure to various experimental concentrations of isoproturon (35-280 ppm), including EC50, significantly and dose-dependently inhibited the mitotic index and induced chromosome breaks/mitotic aberrations at 6 or 24 hr. Conclusion\ The frequency of aberrations was found to be decreased in a dose dependant manner at 24 or 48 hr post exposure, however in comparison of control cells the frequency of aberrations was considerably high which indicates genotoxicity potentials of isoproturon. Further, present study also suggests that Allium sativum is a sensitive, efficient, and reliable test system for measuring the genotoxicity potential of environmental chemicals. 展开更多
关键词 Phenylurea Compounds Chromosome Aberrations DNA Damage Dose-Response Relationship Drug GARLIC HERBICIDES Lethal Dose 50 Methylurea Compounds MITOSIS Mutagenicity tests Plant roots Sensitivity and Specificity
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Effect of Tire Repeated Root Modal on Tire Modelling with Experimental Modal
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作者 Zhenfeng Wang Yongchang Du +1 位作者 Mingming Dong Liang Gu 《Journal of Beijing Institute of Technology》 EI CAS 2017年第1期67-74,共8页
The effect of tire repeated root modal(RRM)on tire modeling with an experimental modal is studied.Firstly,a radial tire with radial and tangential RRMs is tested and analyzed.By multi-point exciting of the radial ti... The effect of tire repeated root modal(RRM)on tire modeling with an experimental modal is studied.Firstly,a radial tire with radial and tangential RRMs is tested and analyzed.By multi-point exciting of the radial tire,a multiple reference frequency domain method based on a least squares(LMS PolyMAX)algorithm is used to identify modal parameters.Then,modal stability diagram(MSD),modal indication function(MIF)and modal assurance criteria(Auto-MAC)matrix are utilized to induce multiple inputs multiple outputs(MIMO)frequency response function(FRF)matrixes.The tests reveal that notable repeated roots exist in both radial and tangential response modes.Their modal frequencies and damping factors are approximately the same,the amplitudes of modal vectors are in the same order of magnitude,and the mode shapes are orthogonal.Based on the works mentioned,the method of trigonometric series modal shapes fitting is adopted,the effects of RRM model on tire modeling with a vertical experimental modal are discussed.The final results show that the effects of considering the RRM shapes are equivalent to the tire mode shapes depended on rotating the tire’s different exciting points during tire modeling,and since considering the RRM,the tire mode shapes can be unified and fixed during tire modeling. 展开更多
关键词 modal test repeated root modal ploy MAX method tire model
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Characterizing the Urban Temperature Trend Using Seasonal Unit Root Analysis:Hong Kong from 1970 to 2015
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作者 Wai-Ming TO Tat-Wai YU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2016年第12期1376-1385,共10页
This paper explores urban temperature in Hong Kong using long-term time series. In particular, the characterization of the urban temperature trend was investigated using the seasonal unit root analysis of monthly mean... This paper explores urban temperature in Hong Kong using long-term time series. In particular, the characterization of the urban temperature trend was investigated using the seasonal unit root analysis of monthly mean air temperature data over the period January 1970 to December 2013. The seasonal unit root test makes it possible to determine the stochastic trend of monthly temperatures using an autoregressive model. The test results showed that mean air temperature has increased by 0.169~ C (10 yr) - 1 over the past four decades. The model of monthly temperature obtained from the seasonal unit root analysis was able to explain 95.9% of the variance in the measured monthly data -- much higher than the variance explained by the ordinary least-squares model using annual mean air temperature data and other studies alike. The model accurately predicted monthly mean air temperatures between January 2014 and December 2015 with a root-mean-square percentage error of 4.2%. The correlation between the predicted and the measured monthly mean air temperatures was 0.989. By analyzing the monthly air temperatures recorded at an urban site and a rural site, it was found that the urban heat island effect led to the urban site being on average 0.865~C warmer than the rural site over the past two decades. Besides, the results of correlation analysis showed that the increase in annual mean air temperature was significantly associated with the increase in population, gross domestic product, urban land use, and energy use, with the R2 values ranging from 0.37 to 0.43. 展开更多
关键词 urban temperature trend urban heat island effect seasonal unit root tests long-term time series
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Pain-related mediators underlie incision-induced mechanical nociception in the dorsal root ganglia
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作者 Xiuhong Yuan Xiangyan Liu +1 位作者 Qiuping Tang Yunlong Deng 《Neural Regeneration Research》 SCIE CAS CSCD 2013年第35期3325-3333,共9页
Approximately 50-70% of patients experience incision-induced mechanical nociception after sur- gery. However, the mechanism underlying incision-induced mechanical nociception is still unclear. Interleukin-10 and brain... Approximately 50-70% of patients experience incision-induced mechanical nociception after sur- gery. However, the mechanism underlying incision-induced mechanical nociception is still unclear. Interleukin-10 and brain-derived neurotrophic factor are important pain mediators, but whether in- terleukin-10 and brain-derived neurotrophic factor are involved in incision-induced mechanical no- ciception remains uncertain. In this study, forty rats were divided randomly into the incision surgery (n = 32) and sham surgery (n = 8) groups. Plantar incision on the central part of left hind paw was performed under anesthesia in rats from the surgery group. Rats in the sham surgery group re- ceived anesthesia, but not an incision. Yon Frey test results showed that, compared with the sham surgery group, incision surgery decreased the withdrawal threshold of rats at 0.5, 3, 6 and 24 hours after incision. Immunofluorescence staining in the dorsal root ganglia of the spinal cord (L3-5) showed that interleukin-10 and brain-derived neurotrophic factor were expressed mainly on small- and medium-sized neurons (diameter 〈 20 pm and 20-40 pm) and satellite cells in the dorsal root ganglia of the spinal cord (L3-5) in the sham surgery group. By contrast, in the surgery group, high expression of interleukin-10 and brain-derived neurotrophic factor appeared in large-sized neurons (diameter 〉 40 pm) at 6 and 24 hours after incision surgery, which corresponded to the decreased mechanical withdrawal threshold of rats in the surgery group. These experimental findings suggest that expression pattern shift of interleukin-10 and brain-derived neurotrophic factor induced by inci- sion surgery in dorsal root ganglia of rats was closely involved in lowering the threshold to me- chanical stimulus in the hind paw following incision surgery. Pain-related mediators induced by in- cision surgery in dorsal root ganglia of rats possibly underlie mechanical nociception in ipsilateral hind paws. 展开更多
关键词 neural regeneration peripheral nerve injury interleukin-lO brain-derived neurotrophic factor rats mechanical nociception dorsal root ganglia INCISION pain-related mediators von Frey test hind paws grants-supported paper neuroregeneration
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Influence of Limited Soil on the Root Distribution and Anchorage of Vitex negundo L.
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作者 LONG Feng LI Shaocai +1 位作者 SUN Hailong LI Chengjun 《Journal of Mountain Science》 SCIE CSCD 2012年第5期723-730,共8页
Field pull-out and laboratory tests were applied to investigate the effect of metal bolts and wire netting on plant root distribution and anchorage characteristics of 9-year-old Vitex negundo L. growing on a weakly we... Field pull-out and laboratory tests were applied to investigate the effect of metal bolts and wire netting on plant root distribution and anchorage characteristics of 9-year-old Vitex negundo L. growing on a weakly weathered rocky slope (38°). Root number, length and diameter were recorded and single root specimens were classified and tested for tensile strength. The results show that root anchorage is different between the two constructions by bolts and wire. Under limited soil condition, root anchorage ability is 80% lower than when there is sufficient soil due to the reduction of the diameter and number of all second-order lateral roots, as well as the reduction of the tensile strength of the embedded second-order and first-order lateral roots on limited soil. We conclude that the distribution and anchorage of Vitex negundo L. is affected by limited soil availability on rocky slopes. 展开更多
关键词 Vitex negundo L. root distribution Ecological engineering Pull-out tests Rocky slope Tensile strength
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Allelopathic Effects of Adonis vernalis L.: Root Growth Inhibition and Cytogenetic Alterations 被引量:1
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作者 Asya Pencheva Dragoeva Vanya Petrova Koleva +1 位作者 Zheni Dimitrova Nanova Borislav Petrov Georgiev 《Journal of Agricultural Chemistry and Environment》 2015年第2期48-55,共8页
A possible alternative to synthetic agricultural chemicals is through the use of allelopathy. Adonis species are rich sources of secondary metabolites. Such allelochemicals offer potential for the development of futur... A possible alternative to synthetic agricultural chemicals is through the use of allelopathy. Adonis species are rich sources of secondary metabolites. Such allelochemicals offer potential for the development of future pesticides. Allelochemicals influence plant growth and cause morphological alterations. This visible effect could be due to primary effects at cellular or molecular level. Changes in the mitotic activity and disturbances in different phases of mitotic division are accepted as indicators of cytotoxic influence. Mitotic abnormalities and induction of micronuclei in interphase cells are parameters used to determine genotoxicity. The purpose of the current study was to establish the possible allelopathic effect of Adonis vernalis L. water extracts through evaluation of root growth inhibition effect and cytogenetic alterations. Adonis vernalis L. growing wild in Bulgaria was used in the present study. Two types of water extracts were prepared: Hot and Cold Water Extract of A. vernalis (HWЕА and СWЕА). A 72-h root growth inhibition test was provided in order to determine the toxicity level of extracts. EC50 values were determined. For toxicity test, seeds of Triticum aestivum L. cv. GTW were used. Cytotoxic and genotoxic potential of water extracts (EC50) were evaluated using Allium cepa L.-test. The EC50 for HWEA and CWEA was determined 1.83 g/l and 0.78 g/l respectively. Significant influence on mitotic activity values and a marked decrease in percentage of telophase cells were observed after treatment with both extracts. Adonis extracts also induced different mitotic abnormalities in root-tip cells of Allium cepa L. The percent of interphase cells with micronuclei increased significantly only after treatment with HWEA. The results indicated growth inhibitory, cytotoxic and genotoxic effects of crude water extracts of A. vernalis L. These effects demonstrated the presence of water soluble allelochemicals in Adonis aerial parts. 展开更多
关键词 Adonis vernalis L. ALLELOPATHY root GROWTH INHIBITION ALLIUM cepa-test
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Preliminary Study on Quality Analysis of Root of Griffith Streptocaulon
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作者 Haisheng ZENG Chengtong LIU +4 位作者 Silu HE Hongming CHEN Xinying MO Yudan LU Xiaobao GUO 《Medicinal Plant》 CAS 2020年第5期53-55,58,共4页
[Objectives]To make a preliminary study on quality analysis of Root of Griffith Streptocaulon.[Methods]The moisture,ash and extract of Root of Griffith Streptocaulon were tested in accordance with the requirements of ... [Objectives]To make a preliminary study on quality analysis of Root of Griffith Streptocaulon.[Methods]The moisture,ash and extract of Root of Griffith Streptocaulon were tested in accordance with the requirements of 2015 Chinese Pharmacopoeia(Volume 4).[Results]The moisture content of Root of Griffith Streptocaulon was not higher than 12.74%,not lower than 6.26%,total ash content was not higher than 15.36%,not lower than 6.17%,acid-insoluble ash content was not higher than 0.55%,not lower than 0.17%,and extract was not higher than 11.83%,not lower than 5.23%.[Conclusions]This experiment made a preliminary study on the quality analysis of the Root of Griffith Streptocaulon,in the hope of providing a scientific basis for its quality control and formulation of the quality standard. 展开更多
关键词 root of Griffith Streptocaulon Quality analysis test
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