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rotation errors in numerical manifold method and a correction based on large deformation theory

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Frontiers of Structural and Civil Engineering 2019年第5期13卷 1036-1053页

作者： Ning ZHANG Xu LI Qinghui JIANG Xingchao LIN School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China Key Laboratory of Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing 100044China School of Civil and Architectural Engineering Wuhan UniversityWuhan 430072China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin Beijing 100038China

Numerical manifold method (NMM) is an effective method for simulating block system, however, significant errors are found in its simulation of rotation problems. Three kinds of errors, as volume expansion, stress vibration, and attenuation of angular velocity, were observed in the original NMM. The first two kind errors are owing to the small deformation assumption and the last one is due to the numerical damping. A large deformation NMM is proposed based on large deformation theory. In this method, the governing equation is derived using Green strain, the large deformation iteration and the open-close iteration are combined, and an updating strategy is proposed. The proposed method is used to analyze block rotation, beam bending, and rock falling problems and the results prove that all three kinds of errors are eliminated in this method.

关键词： numerical manifold method rotation large deformation Green strain open-close iteration

Amplitude and rotation of the ellipticity of harmonics from a linearly polarized laser field

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Chinese Physics B 2022年第10期31卷 88-95页

作者：李萍高娜蔚瑞贤王俊李苏宇郭福明杨玉军 Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy(Jilin University) Changchun 130012China

We simulate the dynamic response of H^(+)_(2) in a linearly polarized laser field by numerically solving the time-dependent Schr?dinger equation.The elliptically polarized high-order harmonics generated by H^(+)_(2)irradiated by the linearly polarized laser field are systematically investigated.The result shows that the amplitude and rotation of the ellipticity of harmonics are affected by the alignment angle and internuclear distance of the molecule.Analyzing the change in forces acted on the ionized electrons and the trajectories of the electrons,the phenomena are found to be due to the change in the direction of the total Coulomb forces from the two nuclei felt by the recollided ionized electrons in the direction perpendicular to the laser polarization direction.Based on the influence law,we can select the harmonics with a specific frequency band under different alignment angles and then synthesize the isolated attosecond pulses with different rotations,which can be continuously converted from right-handed circular polarization,linear polarization,and left-handed circular polarization by changing the alignment angle.This study provides a new possible approach to the real-time detection of molecular states by using attosecond pulses and obtaining more optimized harmonics with molecular properties.

关键词： high-order harmonic ellipticity rotation attosecond pulses

A Meta-analysis of No-tillage Effects on Greenhouse Gas Emissions from Wheat-based rotation Cropping Agroecosystem in China

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Chinese Geographical Science 2023年第3期33卷 503-511页

作者： YAN Guangxuan WANG Jieqi LUO Tingting CHEN Weiwei SHAO Yun LI Chunxi Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control(Ministry of Education) School of EnvironmentHenan Normal UniversityXinxiang 453007China College of Life Sciences Henan Normal UniversityXinxiang 453007China Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchun 130102China

Globally,agricultural soils are considered as one of the most important sources of greenhouse gas(GHG)emissions.No-tillage(NT),one of the most admired ways of climate-smart agriculture,has been deemed to have co-benefit to mitigation of GHG emissions and sustainability for crop yield,however,the effect of NT on GHG emissions is controversial.This study analyzed the overall effects of NT on GHG emissions,as well as the moderators that significantly influenced the overall effects,of the wheat-based rotation cropping systems in China through meta-analysis.The results showed that the overall effect size of NT on methane(CH4)uptake,nitrous oxide(N2O)emission,and global warming potential(GWP)was 0.70(95%Confidence Interval(CI):0.21–1.19),-0.27(95%CI:-0.72–0.18),and-0.39(95%CI:-1.01–0.23),respectively.In temperate climate zones with alkaline soils,the nitrogen application rate of 120–240 kg/ha,NT could significantly reduce GHG emissions and GWP.However,the mitigation effect will be weakened along with NT duration,except for proper straw addition.Overall,NT has the potential to reduce GHG emissions from wheat-based rotation systems in China,but it is necessary to implement NT depending on local conditions,soil characteristics,and field management.

关键词： Wheat soil rotation

Effects of lower limb rotation on the measurement accuracy of coronal alignment in long-leg radiographs after total knee arthroplasty

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Chinese Medical Journal 2022年第5期135卷 619-621页

作者： Mieralimu Muertizha Baochao Ji Abudousaimi Aimaiti Nueralijiang Yushan Li Cao Department of Orthopedics First Affiliated Hospital of Xinjiang Medical UniversityUrumqiXinjiang 830054China

Restoring proper lower limb alignment on the coronal plane after total knee arthroplasty(TKA)can decrease stress in the bone cement-implant interface,polyethylene wear,and implant loosening.Weight-bearing long-leg radiographs(LLRs)are used to assess the mechanical axis in the coronal plane,identify anatomic variations in the femur and tibia,and plan the degree of bone resection preoperatively.However,rotation or flexion of the lower limb may affect the accuracy of the measurement of alignment parameters from LLRs.Furthermore,known rotation-dependent linear changes can be used to relate the degree of lower limb rotation to the alignment parameters of the femur and tibia and the hip-knee-ankle(HKA)angle[1].

关键词： knee implant rotation

The effects of crop rotation combinations on the soil quality of old apple orchard

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Horticultural Plant Journal 2022年第1期8卷 1-10页

作者： Haiyan Wang Yuefan Sheng Weitao Jiang Fengbing Pan Mei Wang Xuesen Chen Xiang Shen Chengmiao Yin Zhiquan Mao College of Horticultural Science and Engineering/State Key Laboratory of Crop Biology Shandong Agricultural UniversityTai’anShandong 271018China

This study investigated the effects of six crop rotation combinations on the soil quality of old apple orchard and seedling growth of Malus hupehensis Rehd.(apple rootstock) under pot conditions. The inhibitory effects of crops such as Allium fistulosum, Brassica juncea, and Triticum aestivum on four species of Fusarium were observed and compared in six treatments. These were continuous cropping(CK), fumigation with the methyl bromide(FM), rotating A. fistulosum only(R1), rotating A. fistulosum and T. aestivum(R2), rotating A. fistulosum, B. juncea, and T. aestivum(R3), and fallow(FC) in a year. The results showed that the biomass of Malus hupehensis Rehd. seedlings increased significantly. The root length increased and the root architecture was optimized. The respiration rate of the root system was increased by about 1 time after rotation. The treatments of R1, R2, R3, and FC increased bacterial count by 232.17%, 96.04%, 316.21%, and 60.02%, respectively. However, the fungi were reduced in varying degrees and bacteria/fungi ratio was increased by 5–10 times. The enzyme activities, p H, and organic matter were increased, but soil bulk density was decreased. Phenolic acids such as phloridzin was decreased significantly. The copy number of four Fusarium species declined by 85.59%, 74.94%, 69.68%, and 54.41% after rotating three different crops(R3 treatment). The root volatiles of three plants inhibited mycelial growth and spore germination of four Fusarium species.

关键词： Apple replant disease rotation Malus hupehensis Rehd Seedlings Soil quality Microorganism

The rotation of the Pacific Plate Induced by the Ontong Java Large Igneous Province

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Journal of Earth Science 2022年第3期33卷 544-551页

作者： Weidong Sun Lipeng Zhang Xi Liu Center of Deep Sea Research Institute of OceanologyCenter for Ocean Mega-ScienceChinese Academy of SciencesQingdao 266071China Laboratory for Marine Mineral Resources Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China School of Marine Sciences University of Chinese Academy of SciencesBeijing 100049China

The eruption of large igneous provinces usually has major geodynamic in fluence sonoverriding plates.Seamount chains indicate that the drifting direction of the Pacific Plate changed by~80°in the Early Cretaceous when the Ontong Java Plateau formed.This,however,is not fully consistent with the magnetic anomalies.Here we show that there is an angle of~25°between the magnetic anomaly lines M_(0)and 34 of both the Japanese and the Hawaiian lineations,suggesting that the orientations of both spreading ridges changed by roughly the same angle towards the same direction.The configurations of the Shatsky Rise,the Papanin Ridge and the Osbourn Trough suggest that the eruption of the Ontong Java plume head uplifted the southeastern corner of the Pacific Plate,and pushed its east part northward by~700 km within 2 Ma.Meanwhile,the west part of the Pacific Plate was subducting southwestward underneath the eastern Asian Continent.These two forces together rotated the Pacific Plate anticlockwisely by ca 50°.Consequently,the drifting direction of the Pacific Plate also changed from southwestward to northwestward,which plausibly explains the ca 80°bending of the Shatsky Rise and the Papanin Ridge.The ridge between the Pacific and the Izanagi/Kula plates was pointed towards the~300°orientation,whereas the Pacific Plate was subducting towards the~250°orientation before~125 Ma,and towards~280°afterward.

关键词： Pacific Plate Ontong Java Plateau rotation magnetic anomalies Shatsky Rise geodynamics

Direct extraction of Mo(Ⅵ) from sulfate solution by synergistic extractants in the rotation column

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Chinese Journal of Chemical Engineering 2020年第2期28卷 445-455页

作者： Benyamin Shakib Meisam Torab-Mostaedi Mohammad Outokesh Mehdi Asadollahzadeh Department of Energy Engineering Sharif University of TechnologyP.O.Box 11365-8639TehranIran Materials and Nuclear Fuel Research School Nuclear Science and Technology Research InstituteP.O.Box:11365-8486TehranIran

Direct extraction of molybdenum from sulfate solution with synergistic extractants(mixture of D2EHPA and TBP)was studied in the rotation column.The influence of extractant concentration and initial pH of aqueous phase was studied in the bench scale experiments.The outcomes demonstrated that the synergistic solvent extraction enhances the constancy of the extracted complexes for transfer into the organic phase.In the continuous experiments,the effect of different operating parameters such as speed of agitation,inlet solvent flow rate and inlet aqueous flow rate on the holdup,mean drop size,drop size distribution,slip and characteristic velocities and extraction percentage were examined.Modified correlations were proposed for prediction of hydrodynamic parameters with consideration of reaction extraction condition in the rotation column.Furthermore,these correlations were compared with the experimental data.According to the results,the direct extraction of Mo(Ⅵ)from aqueous solution and sulfuric media with extraction efficiency of 90.4%was obtained at higher rotor speed(240 r·min–1 rpm)in this column.

关键词： Direct extraction Molybdenum rotation column Synergistic Extractant

Method of ballistic control and projectile rotation in a novel railgun

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Defence Technology（防务技术） 2018年第5期14卷 628-634页

作者： Bo Tang Ying-tao Xu Gang Wan Jiang Yue Yong Jin Hai-yuan Li National Key Laboratory of Transient Physics Nanjing University of Science and Technology

In order to realize the ballistic control of the railgun and the flight stability of the projectile, a new type of railgun is designed, which can control the muzzle velocity and rotation rate. The method of the muzzle velocity and overload control is to adjust the voltage or other parameters of pulse power supply. It would be easy to change velocity accurately in large wide. Another widespread concern problem is launching the spinning stability projectile by railgun. This paper designed a new structure of additional rails to generate an unsymmetrical magnetic field to produce rotational torque in armature. The structure is simple and can control the rotation rate by linear changing the barrel parameters. The calculation formulas of interior ballistic are derived by Biot-Safar law. The important parameter is the deflection angle of the additional rails relative to the symmetry plane of main rail. The larger the angle, the greater the rotation torque generated in the armature. To maintain the flight stability of the projectile, the barrel structural parameters should be proportional to the projectile structural parameters. When changing the muzzle velocity, the rotation rate will also be the equal proportion change. So that the gyro stability is the same. The experiment proves that the railgun designed in this paper can launch the projectile to rotate. And the rotational projectile may not cause the transition or much arcs. This method expands the application of the railgun.

关键词： Ballistic control Railgun rotation Spin-stabilized projectile

Modeling and analysis of solar Doppler difference bias with arbitrary rotation axis

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Chinese Journal of Aeronautics 2020年第12期33卷 3331-3343页

作者： Jin LIU Yangyang LI Xiaolin NING Xiao CHEN Zhiwei KANG College of Information Science and Engineering Wuhan University of Science and TechnologyWuhan 430081China College of Instrument Science and Optoelectronic Engineering Beihang UniversityBeijing 100191China Shanghai Institution of Satellite Engineering Shanghai 200240China College of Information Science and Engineering Hunan UniversityChangsha 410082China

The solar rotation causes the solar Doppler difference bias,which leads to the decline of the velocity measurement accuracy.Modeling and compensation are an effective solution.The limited model with specific geometric direction,where the solar rotation axis is perpendicular to the plane through the Sun,the Earth and Mars,was established.However,in fact,the geometric relationship among the Sun,Mars and the spacecraft is not fully in line with the hypothesis of the model due to the spacecraft orbital angle and the solar rotation axis drift.Thus,this model is not consistent with the fact.In order to solve this problem,a universal solar Doppler difference bias model,which provides the expression with arbitrary rotation axis,is established in this paper.In this method,for any point at the solar surface,four variables including the direction of the solar rotation linear velocity at this point,the distance from this point to the rotation axis,the vector from this point to Mars,and the vector from this point to the spacecraft are calculated.Based on these four variables,the solar Doppler difference bias corresponding to this point is obtained.The theoretical analysis and simulation results demonstrate that the solar Doppler difference bias model with the actual rotation axis is different from that with one of the specific rotation axes.Therefore,it is indispensable to build the proposed model for compensation.Besides,the direction of the solar rotation axis,the spacecraft-Mars-Sun angle and the spacecraft-to-Mars distance are important impact factors for the proposed model.

关键词： Bias Doppler navigation Measurement Modeling rotation