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Smoothness-oriented path optimization for robotic milling processes

Science China(Technological Sciences) 2020年第9期63卷 1751-1763页

作者： peng JingFu DING Ye ZHANG gang DING Han State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai200240China HUST-Wuxi Research Institute Wuxi214174China

Industrial robots are increasingly used for five-axis machining operations, where the rotation of the end effector along the toolaxis direction is functionally redundant. This functional redundancy should be carefully resolved when planning the robot path according to the tool path generated by a computer-aided manufacturing(CAM) system. Improper planning of the redundancy may cause drastic variations of the joint motions, which could significantly decrease the machining efficiency as well as the machining accuracy. To tackle this problem, this paper presents a new optimization-based methodology to globally resolve the functional redundancy for the robotic milling process. Firstly, a global performance index concerning the smoothness of the robot path at the joint acceleration level is proposed. By minimizing the smoothness performance index while considering the avoidance of joint limits and the singularity and the constraint of the stiffness performance, the resolution of the redundancy is formulated as a constrained optimization problem. To efficiently solve the problem, the sequential linearization programming method is employed to improve the initial solution provided by the conventional graph-based method. Then, simulations for a given tool path are presented. Compared with the graph-based method, the proposed method can generate a smoother robot path in which a significant reduction of the magnitude of the maximum joint acceleration is obtained, resulting in a smoother tool-tip feedrate profile. Finally, the experiment on the robotic milling system is also presented. The results show that the optimized robot path of the proposed method obtains better surface quality and higher machining efficiency, which verifies the effectiveness of the proposed method.

关键词： robot milling functional redundancy path optimization smoothness sequential linear programming

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Landslide Developmental Characteristics and Response to Climate Change since the Last Glacial in the Upper Reaches of the Yellow River, NE Tibetan Plateau

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Acta Geologica Sinica(English Edition) 2014年第2期88卷 635-646页

作者： yin Zhiqiang QIN Xiaoguang yin Yueping ZHAO Wuji WEI gang Institute of Geology and Geophysics Chinese Academy of Sciences China Institute of Geo-environment Monitoring China University of Geosciences (Beijing) Qinghai Environmental Geological Prospecting Bureau

The upper reaches of the Yellow River in northeastern Tibetan Plateau are geohazards *** evolution of the Yellow River,chronology of some landslides,and spatiotemporal distribution characteristics of super large scale and giant landslides within the region are summarized using paleoclimate evidence,and the relationship between the intensive landslide period and climatic changes since the Last Glacial period is *** is concluded that （1） Super large scale and giant landslides are distributed widely within the region,particularly in the Qunke-Jianzha basin.（2） The chronological sequence of landslides is established by dating the slip zones of landslides and analyzing the relations between landslides and their overlying or underlying loess *** landslide development periods are determined：53-49 ka BP,33-24 ka BP,10-8 ka BP,5-3.5 ka BP,and the present.（3） These correspond closely to warm and wet periods during the last 100,000 years,i.e.,two weak paleosol development stages of Malan loess deposited during the last Glacial period in the Chinese loess Plateau,L1-4 and L1-2 that belong to the marine oxygen isotope stage 3,the last deglaeial period,the Holocene Optimum,and the modern global warming period.（4） Landslide triggers may be closely linked to warm and wet periods related to rapid climatic transitions.

关键词： landslide developmental characteristics climate change upper reaches of the Yellow River response

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Pursuing innovation in a new era

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ZOOLOGICAL RESEARCH 2024年第6期45卷 1232-1234页

作者： Yao, Yong-gang Shi, peng Chinese Acad Sci Kunming Inst Zool Kunming 650223 Yunnan Peoples R China

This year marks a significant milestone as we celebrate the75th anniversary of our nation,alongside the 65th anniversary of the Kunming Institute of Zoology(KIZ) and the 75^(th) anniversary of the Chinese Academy of Sciences(CAS).This juncture provides an opportunity to reflect on our progress over the past five years and strategically enhance our culture of innovation,while pursuing new aspirations(Yao & Shen,2019).It is a critical moment to advance innovation and take decisive steps toward leadership in this new era.

关键词： steps anniversary strategic

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Accurate structural descriptor enabled screening for nitrogen and oxygen vacancy codoped TiO_(2) with a large bandgap narrowing

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Journal of Materials Science & Technology 2022年第27期122卷 84-90页

作者： Kangyu Zhang Lichang yin gang Liu Hui-Ming Cheng Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Department of Physics and Electronic Information Huaibei Normal UniversityHuaibei 235000China

Nitrogen(N)doping has been widely adopted to improve the light absorption of TiO_(2).However,the newly introduced N-2p states are largely localized thus barely overlap with O-2p states in the valence band of TiO_(2),resulting in a shoulder-like absorption *** realize an apparent overlap between N-2p and O-2p states,charge compensation between N^(3-)and O^(2-)via electron transfer from oxygen vacancies(VO)to N dopants is one possible *** verify this,in numerous doping configurations of N/VO-codoped anatase TiO_(2),we identified two types of VOposition independent N-dopant spatial orderings by efficient screening enabled with a newly designed structural *** with others,these two types of the N-dopant spatial orderings are highly beneficial for charge compensation to produce an apparent overlap between N-2p and O-2p states,therefore achieving a large bandgap ***,the two types of the N-dopant spatial orderings can also be generalized to N/VO-codoped rutile TiO_(2)for bandgap narrowing.

关键词： Structural descriptor TiO_(2) Bandgap narrowing Doping Machine learning Density functional theory

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Internal Friction in Bi-material Specimens

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Chinese Physics Letters 1999年第8期16卷 589-590页

作者： CHEN gang ZHU Zhen-gang SHUI Jia-peng Laboratory of Internal friction and Defects in Solids Institute of Solid State PhysicsChinese Academy of SciencesHefei 230031

A new kind of bi-material specimen is employed in an inverted torsion pendulum to study the internal friction in liquids,and especially in materials during liquid-solid or solid-liquid *** systems containing a bi-material specimen with a solid or a liquid inner material can be described by using a modified three-parameter mechanical *** theoretical results agree well with experimental data.

关键词： liquid torsion transitions

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Rapid detection to long ship wake in synthetic aperture radar satellite imagery

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Journal of Oceanology and Limnology 2019年第5期37卷 1523-1532页

作者： CHEN peng LI Xiunan ZHENG gang Second Institute of Oceanography Ministry of Natural Resources

The maritime administrative department employs synthetic aperture radar (SAR) satellite remote sensing technology to obtain evidence of illegal discharge of ships. If the ship is discharged during navigation, it forms a long dark wake on the SAR image due to the suppression of the Bragg wave by the oil fi lm. This study investigates key techniques for rapid detection of long ship wakes, thereby providing law enforcement agencies with candidate ships for possible discharge. This paper presents a rapid long ship wake detection method that uses satellite imaging parameters and the axial direction of the ship in images to determine the potential detection area of the wake. Then, the threshold of long ship wake detection is determined using statistical analysis, the area is binarized, and isolated points are removed using a morphological filter operator. The method was tested with ENVISAT Synthetic Aperture Radar and GF-3 SAR data, and results showed that the method was eff ective, and the overall accuracy of the decision reaches 71%. We present two innovations;one is a method that draws a Doppler shift curve, and uses the SAR imaging parameters to determine the detection area of the long wake to achieve rapid detection and reduce the image detection area. The other is where a classical linear fitting method is used to quickly and accurately determine whether the detected dark area is a long ship wake and realizes the twisted long ship wake detection caused by the sea surface flow field, which is otherwise diffi cult to detect by the traditional Radon and Hough transform methods. This method has good suppression performance for the dark spot false alarm formed by low speed wind region or upward flow. The method is developed for maritime ship monitoring system and will promote the operational application of maritime ship monitoring system.

关键词： marine pollution illegal discharge linear fi t oil spill synthetic aperture radar (SAR) long ship wake

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Theoretical design of thermal spin molecular logic gates by using a combinational molecular junction

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Chinese Physics B 2022年第4期31卷 616-621页

作者： Yi Guo peng Zhao gang Chen School of Physics and Technology University of JinanJinan 250022China School of Physics and Electronics Shandong Normal UniversityJinan 250358China

Based on the density functional theory combined with the nonequilibrium Green function methodology,we have studied the thermally-driven spin-dependent transport properties of a combinational molecular junction consisting of a planar four-coordinate Fe molecule and a 15,16-dinitrile dihydropyrene/cyclophanediene molecule,with single-walled carbon nanotube bridge and *** results show that the magnetic field and light can effectively regulate the thermallydriven spin-dependent *** thermal spin-filtering effect and good thermal switching effect are *** results are explained by the Fermi-Dirac distribution function,the spin-resolved transmission spectra,the spatial distribution of molecular projected self-consistent Hamiltonian orbitals,and the spin-resolved current *** the basis of these thermally-driven spin-dependent transport properties,we have further designed three basic thermal spin molecular AND,OR,and NOT gates.

关键词： thermal molecular logic gate thermally-driven spin-dependent transport combinational molecular junction nonequilibrium Green's function

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Compound jet generated from an impacted concave dual-layer liquid surface

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Journal of Hydrodynamics 2021年第2期33卷 390-394页

作者： Xiang-gang Cheng Xiao-peng Chen School of Marine Science and Technology Northwestern Polytechnical UniversityXi'an 710072China

By impacting a concave dual-layer liquid(with the oil and the dyed water)surface in a test tube,a compound jet with a water core and an oil shell is *** velocities of the jet's head(Vj)and the oil-water interface(Vj')are experimentally determined against the initial thickness and the viscosity of the upper layer *** results show that the oil-water interface can be roughly regarded as a pure material surface,whose velocity can be determined from the jet velocity and the initial location(or the film thickness).Furthermore,the effective density,viscosity and surface tension of the compound jet are used to evaluate the jetting *** previous scaling relation for a single liquid jet can be used to give a good prediction with the effective *** results of this paper can be used for the compound jet/droplet preparation.

关键词： Compound jet dual-layer liquid viscosity interface tension

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Simulating heavy fermion physics in optical lattice： Periodic Anderson model with harmonic trapping potential

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Frontiers of physics 2017年第5期12卷 71-80页

作者： yin Zhong Yu Liu Hong-gang Luo Center for Interdisciplinary Studies & Key Laboratory for Magnetism and Magnetic Materials of the MoE Lanzhou University Lanzhou 730000 China LCP Institute of Applied Physics and Computational Mathematics Beijing 100088 China Sof-tware Center for High Performance Numerical Simulation China Academy of Engineering Physics Beijing 100088 China Beijing Computational Science Research Center Beijing 100084 China

The periodic Anderson model （PAM）, where local electron orbitals interplay with itinerant electronic carriers, plays an essential role in our understanding of heavy fermion materials. Motivated by recent proposals for simulating the Kondo lattice model （KLM） in terms of alkaline-earth metal atoms, we take another step toward the simulation of PAM, which includes the crucial charge/valence fluctuation of local f-electrons beyond purely low-energy spin fluctuation in the KLM. To realize PAM, a transition induced by a suitable laser between the electronic excited and ground state of alkaline-earth metal atoms （^1S0←→^3P0） is introduced. This leads to effective hybridization between local electrons and conduction electrons in PAM. Generally, the SU（N） version of PAM can be realized by our proposal, which gives a unique opportunity to detect large-N physics without complexity in realistic materials. In the present work, high-temperature physical features of standard [SU（2）] PAM with harmonic trapping potential are analyzed by quantum Monte Carlo and dynamic mean-field theory, where the Mott/orbital-selective Mott state was found to coexist with metallic states. Indications for near-future experiments are provided. We expect our theoretical proposal and （hopefully） forthcoming experiments will deepen our understanding of heavy fermion systems. At the same time, we hope these will trigger further studies on related Mott physics, quantum criticality, and non-trivial topology in both the inhomogeneous and nonequilibrium realms.

关键词： optical lattice heavy fermion Mort transition

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Soil-nitrogen net mineralization increased after nearly six years of continuous nitrogen additions in a subtropical bamboo ecosystem

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Journal of Forestry Research 2015年第4期26卷 949-956页

作者： yin-long Xiao Li-hua Tu gang Chen Yong peng Hong-ling Hu Ting-xing Hu Li Liu College of Forestry Sichuan Agricultural University Personnel Department Sichuan Agricultural University

In order to understand the effects of increasing atmospheric nitrogen （N） deposition on the subtropical bamboo ecosystem, a nearly six-year field experiment was conducted in a Pleioblastus amarus plantation in the rainy region of SW China, near the western edge of Sichuan Basin. Four N treatment levels---control （no N added）, low- N （50 kg N ha-1 a-l）, medium-N （150 kg N ha-1 a-l）, and high-N （300 kg N ha-1 a-1）--were applied monthly in the P. amarus plantation starting in November 2007. In June 2012, we collected intact soil cores in the bamboo plantation and conducted a 30-day laboratory incubation experiment. The results showed that the soil N net miner- alization rate was 0.96 4- 0.10 mg N kg-1 day-1, under control treatment. N additions stimulated the soil N net mineralization, and the high-N treatment significantly increased the soil N net mineralization rate compared with the control. Moreover, the soil N net mineralization rate was significantly and positively correlated with the fine root biomass, the soil microbial biomass nitrogen content and the soil initial inorganic N content, respectively,whereas it was negatively correlated with the soil pH value. There were no significant relationships between the soil N net mineralization rate and the soil total nitrogen （TN） content and the soil total organic carbon content and the soil C/N ratio and the soil microbial biomass carbon con- tent, respectively. These results suggest that N additions would improve the mineral N availability in the topsoil of the P. amarus plantation through the effects of N additions on soil chemical and physical characteristics and fine-root biomass.

关键词： Nitrogen addition Soil nitrogen net mineralization Soil chemical and physical characteristics Fine root biomass Pleioblastus amarus plantation

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