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Modeling slow deformation of polygonal particles using DEM

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Particuology 2008年第6期6卷 506-514页

作者： Andrés A. Pea Pedro G. Lind Hans J. Herrmann Institute for Computational Physics Universitt Stuttgart Computational Physics IfB HIF E12 ETH Hnggerberg CH-8093 Zrich Switzerland Departamento de física Universidade Federal do Ceará

We introduce two improvements in the numerical scheme to simulate collision and slow shearing of irregular particles. first, we propose an alternative approach based on simple relations to compute the frictional contact forces. The approach improves efficiency and accuracy of the Discrete Element Method （DEM） when modeling the dynamics of the granular packing. We determine the proper upper limit for the integration step in the standard numerical scheme using a wide range of material parameters. To this end, we study the kinetic energy decay in a stress controlled test between two particles. second, we show that the usual way of defining the contact plane between two polygonal particles is, in general, not unique which leads to discontinuities in the direction of the contact plane while particles move. To solve this drawback, we introduce an accurate definition for the contact plane based on the shape of the overlap area between touching particles, which evolves continuously in time.

关键词： Granular media Discrete element method slow deformation Contact forces

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YOU'LL BE HEARING fROM ME!——英语“将来进行”式探讨

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外国语(上海外国语大学学报) 1981年第3期 19-23+18页

作者： s.f.Whitaker ,张月祥

本刊于1978年第二期发表了关于英语动词“时”和“体”的研究文章,并加发编者按,希望对这个问题展开讨论。此后,本刊编辑部经常收到国内外读者的来信来稿就这个问题发表自己的见解。本文作者s.f.惠特克(***)是英国北威尔士大学高级讲师,... 详细信息

本刊于1978年第二期发表了关于英语动词“时”和“体”的研究文章,并加发编者按,希望对这个问题展开讨论。此后,本刊编辑部经常收到国内外读者的来信来稿就这个问题发表自己的见解。本文作者s.f.惠特克(***)是英国北威尔士大学高级讲师,1978年曾应邀来我国讲学。他读后很感兴趣,并撰文阐述他对这一问题的看法。由于惠氏原文较长,现特将其主要论述部分译出。

关键词：事件动词含义 will 进行体英语 YOU’LL BE HEARING fROM ME BE

Electrical and mechanical studies on ferroelectric lithium rubidium sulphate crystals

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Journal of Advanced Dielectrics 2018年第3期8卷 17-27页

作者： f.A.Najar G.B.Vakil B.Want Department of Physics University of Kashmir Srinagar 190006India solid state Research Laboratory Department of Physics University of KashmirSrinagar 190006India

slow evaporation method was used to grow single crystals of lithium rubidium sulphate with high *** crystal X-ray diffraction analysis shows that at room temperature,the crystal belongs to a monoclinic system with the space group P21/*** physical parameters like plasma energy,Penn gap,fermi energy and electronic polarizability have been evaluated for the grown *** relation between electronic polarizability and diamagnetic susceptibility for the crystal has been established on the basis of Kirkwood’s semiempirical *** ac conductivity and dielectric behavior of the grown crystal were systemically investigated as a function of frequency and *** title compound obeys Jonscher’s power law relations:ð(ω)=σo+Aω^(s),with exponent sstudy,it is observed that both small and large polarons take part in conduction process,and at low temperature,both the band and hopping mechanisms are responsible for *** impedance and modulus studies,it is observed that only one conduction relaxation is observed in the crystal at low *** activation energy of the dielectric relaxation(0.41 eV)and that of the conduction(Econd¼0:43 eV)are in agreement,as a result,there is no difference among the conduction and relaxation species at high *** scanning calorimetric analysis of the crystal shows three endothermic peaks at 166℃,185℃,and 202℃,from which various thermodynamic parameters such asΔH,Δs andΔC_(p) have been *** Vickers hardness test,we have determined the mechanical strength,and other parameters which include fracture toughness,brittleness index,yield strength,and stiffness constant for the crystal.

关键词： slow evaporation monoclinic conductivity impedance activation energy

Non-suicidal self-injury in shanghai inner bound middle school students

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General Psychiatry 2019年第4期32卷 206-213页

作者： fang Zhang Paula f Cloutier Hongmei Yang Wenjing Liu Wenhong Cheng Zeping Xiao departm ent of Medical psychology Shanghai General hospitalMedical School of Shang Hai Jiaotong UniversityShanghaiChina Children's Hospital of Eastern Ontario OttawaOntarioCanada shanghai Jing'an Education College ShanghaiChina shanghai Mental Health Center Medical School of Shang Hai Jiaotong UniversityShanghaiChina

Background Non-suicidal self-injury (NssI) behaviour is very common among adolescents. Its prevalence and behavioural characteristics may vary according to regional and cultural differences. Investigation of NssI locations and diagnosis of adolescents with NssI are relatively lacking in China. Aims The study objective was to determine the prevalence and features of NssI among middle school students in shanghai. Methods The participants were from grade 6 to 8 selected from three junior schools in Jing’an District. Consenting students completed the Ottawa self-Injury Inventory to determine the prevalence and characteristics of NssI. Those who indicated NssI within the past month were administered the Mini-International Neuropsychiatric Interview for Children and Adolescents to assess.f.r emotional disorders. Result The result shows 510 participants (21.7%;mean age 13.51 (0.97) years old;56.7% female) reported at least one instance of NssI during the previous 12 months. NssI was significantly more common in girls than boys (24.9% vs 18.5%;χ^2=14.03, p=0.00). Commonly reported reasons.f.r NssI were for internal and external emotion regulation (87.9%, 82.3%) and social influence (57.8%). Anxiety disorders were the most common (28.9%) disorder associated with NssI. Conclusion The rate of NssI of middle school students in shanghai inner bound is similar to those reported in North American and European youth. It is essential that school mental health professionals are aware of how to manage NssI within the school setting.

关键词： middle school students Non-suicidal self-injury

Modeling and simulation of Two Axes Gimbal Using fuzzy Control

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Computers, Materials & Continua 2022年第7期72卷 93-107页

作者： Ayman A.Aly Mohamed O.Elhabib Bassem f.felemban B.saleh Dac-Nhuong Le Department of Mechanical Engineering College of EngineeringTaif UniversityTaif21944Saudi Arabia Control and Mechatronics Division School of Electrical EngineeringUTMJohor Bahru81300Malaysia Institute of Research and Development Duy Tan UniversityDanang550000Vietnam school of Computer science Duy Tan UniversityDanang550000Vietnam

The application of the guided missile seeker is to provide stability to the sensor’s line of sight toward a target by isolating it from the missile motion and *** main objective of this paper is not only to present the physical modeling of two axes gimbal system but also to improve its performance through using fuzzy logic controlling *** paper is started by deriving the mathematical model for gimbals motion using Newton’s second law,followed by designing the mechanical parts of model using sOLIDWORKs and converted to xml file to connect dc motors and sensors using MATLAB/***,a Mamdani-type fuzzy and a Proportional-Integral-Derivative(PID)controllers were designed using MATLAB *** performance of both controllers was evaluated and tested for different types of input *** simulation results showed that self-tuning fuzzy controller provides better performance,since no overshoot,small steady-state error and small settling time compared to PID controller.

关键词： Gimbal system self-tuning fuzzy proportional-integral-derivative(PID)control cross coupling

Temperature Based spatiotemporal Growth Monitoring of Rice Plant from Germination-Ripening stage Using Remote sensing and GIs Techniques

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Advances in Remote sensing 2018年第1期7卷 1-14页

作者： s. M. H. Raza s. A. Mahmood H. Batool T. J. shad s. Alvi f. Waseems M. Atif Butt s. shehzad Hassan Ali Imam Mirza Remote sensing and GIs Group Department of Space Science University of the Punjab Quaid-e-Azam Campus Lahore Pakistan Department of Geography University of the Punjab Quaid e Azam Campus Lahore Pakistan

Rice (Oryza sativa) is the second staple food largely grown and widely consumed in Pakistan. About 10% of the total crop area of Pakistan is cultivated by rice that takes a part in value addition of almost 1.3% - 1.6% in the total Gross Domestic Product (GDP). Due to global warming, temperature has a profound impact on rice crop phenology. Low temperature is the main factor of delay in rice plant growth and very high temperature results in stressed and short heighted plant so the crop sown in a region at the same time is not ready to harvest at same hours but a delay is observed. The study area under investigation was district sheikhupura, Nankana, Lahore, Gujranawala and Hafizabad, which are famous.f.r rice productivity. Landsat 7, 8 freely available thermal dataset are used to calculated pixel based temperature values to evaluate growth using agricultural growth indicators. The total covered area was 13,480 km2 in which 484 km2 area was marked as less growth rate area with low temperature values due to water body and excess of vegetation over there. About 7960 km2 area is marked as good for growth experiencing optimum temperature for rice plant. Approximately 4944 km2 area is marked as stressed rice plant area experiencing high temperature values adjacent to urban population. An attempt is made here to map this effect of temperature-based growth variability of the rice plant across the study area.

关键词： Climate Gross Domestic Product (GDP) Global Warming Phenology Temperature

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用电子计算机控制钻进

国外地质勘探技术 1980年第12期 58-65页

作者： f.s.young 张运钧

钻探设备操作自动化是探矿工程发展的方向之一。未来的钻进操作,其基本目标是寻求工艺技术和自动控制的最佳配合,以便降低钻探成本,提高生产效率。世界上不少国家在自动化控制钻进方面进行了探索和尝试,取得了一些经验。现将美国Humble... 详细信息

钻探设备操作自动化是探矿工程发展的方向之一。未来的钻进操作,其基本目标是寻求工艺技术和自动控制的最佳配合,以便降低钻探成本,提高生产效率。世界上不少国家在自动化控制钻进方面进行了探索和尝试,取得了一些经验。现将美国Humble石油公司发明的一种现场使用的电子计算机设

关键词：钻压测试点计算机旋转速度转速计算机控制系统钻头轴承钻探成本扭矩钻进速度

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重力磁力数据处理及解释方法的回顾

石油地球物理勘探 1973年第6期 83-93页

作者： f·s·格兰特物探局研究所

本文回顾了1964-1971年期间重磁力数据处理及解释方面的文献,内容包括野外观测,数据计算,自动绘等值线,平面图分析,解释技术及应用。两种方法都大量采用计算机进行自动处理和半自动解释。今后发展的关键将在于如何巧用显示设备。

关键词：计算机文章海上重力测量重力中心力

B-GQDs@GsH as a Highly selective and sensitive fluorescent Probe for the Detection of fe^(3+) in Water samples and Intracellular

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Journal of Analysis and Testing 2023年第2期7卷 147-156页

作者： Xiaohua Yang Peigang Zhang Jie Tan Xuebing Li Weidong Zhang Wei Bian Martin M.f.Choi Department of Biochemistry and Molecular Biology School of Basic Medical ScienceShanxi Medical UniversityTaiyuan 030001China Lvliang People’s Hospital Lvliang 033000China Department of Traditional Chinese Medicine the First Hospital of Shanxi Medical UniversityTaiyuan 030001China

Owing to the excellent stability,biocompatibility and photoluminescence property,graphene quantum dots(GQDs)are emerging as a kind of potential materials to be applied in a series of fields ranging from sensor to drug *** the growing concern for human and environmental s.f.ty,selective detection of metal ions has been paid more and more ***,as nanoparticles with superior optical properties,have been attracting growing attention in the field of metal ions *** this work,glutathione(GsH)functionalized boron doped graphene quantum dots(B-GQDs@GsH)were succes.f.lly synthesized with stable bright blue fluorescence and has been used for the detection of fe^(3+).A good linear relationship between 1/(f_(0)-f)and 1/c with the concentration ranging from 0.70 to 53μmol/L was obtained with a detection limit of 5.5 nmol/*** application of B-GQDs@GsH for fe^(3+)detection in water samples was demonstrated and the quenching mechanism was.f.rther *** to low cytotoxicity and favorable biocompatibility,B-GQDs@GsH were succes.f.lly applied for cell fluorescence imaging and intracellular determination of fe^(3+).

关键词： fluorescence probe Quenching mechanism Real samples detection Intracellular detection

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