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Point Cloud Classification Using Content-Based Transformer via Clustering in Feature Space

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 231-239页

作者： Yahui liu {1. Tian Yisheng Lv lingxi li Fei-Yue wang the State Key Laboratory for Management and Control of Complex Systems Institute of AutomationChinese Academy of SciencesBeijing 100190 the School of Artificial Intelligence University of Chinese Academy of SciencesBeijing 100190 IEEE the Transportation and Autonomous Systems Institute(TASI)and the department of Electrical and Computer Engineering Purdue School of Engineering and TechnologyIndiana University-Purdue University Indianapolis(IUPUI)Indianapolis 46202 USA

Recently, there have been some attempts of Transformer in 3D point cloud classification. In order to reduce computations, most existing methods focus on local spatial attention,but ignore their content and fail to establish relationships between distant but relevant points. To overcome the limitation of local spatial attention, we propose a point content-based Transformer architecture, called PointConT for short. It exploits the locality of points in the feature space(content-based), which clusters the sampled points with similar features into the same class and computes the self-attention within each class, thus enabling an effective trade-off between capturing long-range dependencies and computational complexity. We further introduce an inception feature aggregator for point cloud classification, which uses parallel structures to aggregate high-frequency and low-frequency information in each branch separately. Extensive experiments show that our PointConT model achieves a remarkable performance on point cloud shape classification. Especially, our method exhibits 90.3% Top-1.accuracy on the hardest setting of ScanObjectN N. Source code of this paper is available at https://***/yahuiliu99/PointC onT.

关键词： Content-based Transformer deep learning feature aggregator local attention point cloud classification

A preliminary study on vegetation-erosion dynamics and its applications

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Science China Earth Sciences 2005年第5期48卷 689-700页

作者： wang Zhaoyin 1.2 , wang Guangqian 1., li Changzhi 1.& wang Feixin 1.1. department of Hydraulic Engineering, Tsinghua university, Beijing 1.0084, China 2. International Research and Training Center on Erosion and Sedimentation, Beijing 1.0084, China 1. department of Hydrau{1.c Engineering Tsinghua University 100084 Beijing China 2. International Research and Training Center on Erosion and Sedimentation 100084 Beijing China

Vegetation-erosion dynamics is a new interdisciplinary science, studying the laws of evolution of watershed vegetation under the action of various ecological stresses. Introducing a qualitative expression of ecological stresses in this paper, the present authors establish the cou- pled differential equations for the vegetation-erosion process and derive a theoretical solution. The model is applied to the Anjiagou watershed on the Loess Pateau and the Xiaojiang water- shed and its sub-watersheds on the Yunnan Plateau. The calculated results agree well with the vegetation development processes. Abstracted from the differential equations the so-called vegetation-erosion chart is worked out, with which we can predict the development trend of vegetation under no human stresses. It is demonstrated that the erosion control is important for vegetation development and reforestation must be a long-term strategy. On the Yunnan Plateau with relatively high precipitation and temperature, vegetation can be greatly improved if erosion is controlled. On the dry and cold Loess Pateau suffering from high rate of soil erosion, however, vegetation can effectively control erosion but erosion reduction exhibits low effectiveness on vegetation development. Vegetation in the area is not stable and management is always needed to maintain the vegetation.

关键词： vegetation-erosion dynamics, human activities, coupled differential equations, erosion control, vigor ofvegetation.

lipschitz continuity of best approximations and Chebyshev centers

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Chinese Science Bulletin 1998年第3期43卷 185-188页

作者： li Chong {1. {1. Xinghua 2 1. Center for Mathematical Sciences, Zhejiang university, Hangzhou 31.027, China 2. department of Mathematics, Hangzhou university, Hangzhou 31.028, China Center for Mathematical Sciences Zhejiang University Hangzhou China department of Mathematics Hangzhou University Hangzhou China

The lipschitz continuity results are given for best approximations and Chebyshev centers. Consequently, the open problem presented by Septycki and Vleck is solved completely.

关键词： best approximation Chebyshev center uniform convexity.

Effect of acid oxidization of carbon nanotube electrode on the capacitances of double layer capacitors

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Science China(Technological Sciences) 2004年第3期47卷 257-264页

作者： li Chensha1.{1. Dazhi1.liANG Tongxiang2,{1. Xiaofeng1.& liANG Ji1.1. department of Mechanical Engineering, Tsinghua university,Beijing 1.0084, China 2. Institute of Nuclear Energy Technology, Tsinghua university,Beijng 1.2201.China Tsinghua Univ Dept Mech Engn Beijing 100084 Peoples R China Tsinghua Univ Inst Nucl Energy Technol Beijing 102201 Peoples R China

Polarizable electrode of electric double layer capacitor was made from carbon nanotubes. The effect of acid oxidation of electrode on the specific capacitance was studied. Oxidation removed the redundant carbon, expanded the pore size and introducedf some kinds of functional groups on the surface of CNTs. The specific capacitance of the electrodes winth organic electrolyte was increased from 21.4 to 49.6 F/g after being oxidized at a volume ratio H2SO4 to HNO3 of 3:1.

关键词： carbon nanotubes, electric double layer capacitor, specific capacitance.

Electroluminescent properties of three ternary europium complexes with different phenanthroline derivatives

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Science China chemistry 2004年第4期47卷 326-334页

作者： BIAN Zuqiang1.2, GAO Deqing1. GUAN Min1. XIN Hao1. li Fuyou1. HUANG Chunhui1. {1. Kezhi2 & JIN linpei2 1. State Key Laboratory of Rare Earth Materials {1. and Applications, Peking university, Beijing 1.0871. China 2. department of {1., Beijing Normal university, Beijing 1.0875, China 1. State Key Laboratory of Rare Earth Materials chemistry and App{1.cations Peking University 100871 Beijing China 2. department of {1. Beijing Normal University 100875 Beijing China

Three ternary Eu(III) complexes with general formula of Eu(DBM)3LN (DBM = dibenzoylmethanate, and LN (N = 1.3 ) stand for three different 1.1.-phenanthroline derivatives) have been synthesized for vacuum deposition films-based electroluminescent devices. The complex Eu(DBM)3L3 (L3 = 2-phenyl-3-[3-(carbazol-9-yl)propyl]imidazo[4,5-f]1.1.-phenan-throline) was designed with an effort to combine the electron-transporting phenanthroline platform and the hole-transporting carbazole group into one molecule expecting to improve both electron and hole transporting properties simultaneously. The results show that the variation of the neutral ligands in Eu(III) mixed ligand complexes is a simple and effective approach to the improvement in the thermal stability, PL and EL properties of materials. A double-layer device with the configuration of ITO/TPD (50 nm)/Eu(DBM)3L3 (50 nm)/Mg0.9Ag0.1.(200 nm)/Ag (1.0 nm) exhibited Eu(III)-based pure red emission with a maximum brightness of 561.cd/m2 at 1. V, and an onset driving voltage of 8 V. A device with the configuration of ITO/TPD (50 nm)/[Eu(DBM)3L3 (5 nm):BCP (5 nm)]4/BCP (20 nm)/AIQ (1. nm) Mg0.9Ag0.9 (1.0 nm)/Ag (1.0 nm) gave high efficient and pure red light emission with a luminance of 1.1. cd/m2. Keywords dibenzoylmethane - electroluminescence - lanthanide - N ligands

关键词： dibenzoylmethane electroluminescence lanthanide N ligands

Giant negative electrocaloric effect measured by indirect method in X-ray irradiated P(VDF-TrFE)films

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Journal of Materiomics 2024年第3期10卷 624-631页

作者： Bo li {1. Yang Hong Zhang Jiajia Zhang Qianjin wang Weishu liu department of Materials Science and Engineering Southern University of Science and TechnologyShenzhenGuangdong 518055China Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices Southern University of Science and TechnologyShenzhenChina College of Physics and Electronic Information Yunnan Normal UniversityYunnan Kunming 650500China The Science and Technology on Reliability Physics and Application of Electronic Component Laboratory China Electronic Product Reliability and Environmental Testing Research InstituteGuangzhou 510610China

Flexible solid-state cooling devices with high efficiency are attracted to ferroelectric polymers with excellent negative electrocaloric(EC)*** is challenging to obtain a large negative EC effect in ferroelectric polymers due to the lack of tunable techniques.A giant negative EC response was obtained in the poly(vinylidene fluoride-trifluoroethylene)copolymers(P(VDF-TrFE),70/30,in mole ratio)irra-diated with high-energy *** irradiated P(VDF-TrFE)films showed an adiabatic temperature change of-1..5 K at 40 MV/m under a dose of 5 Mrad(1.Mrad=1.^(4) J/kg)obtained by the indirect *** significant negative EC effect is attributed to the enhancement of crystalline due to the entry of polymer molecules into the amorphous to crystalline structure and the reduction of heat ca-pacity due to the increase of *** addition,X-ray irradiation improves the dielectric coefficient from 1. to *** research indicates that irradiation can modify the negative EC properties of ferro-electric polymers for solid-state cooling.

关键词： Negative electrocaloric effects X-rays radiation P(VDF-TrFE)films

Recurrence spectra of He atoms in strong external fields

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Science China(Physics,Mechanics & Astronomy) 2004年第4期47卷 477-484页

作者： liN Shenglu1. li Hongyun1. wang Dehua2, ZHAO Wenli1.& GAO Feng1.1. {1. of Physics, Shandong Normal university, Jinan 25001., China 2. {1. of Mathematics and Physics, Shandong Institute of Architecture and Engineering, Jinan 25001., China 1. department of Physics Shandong Normal University 250014 Jinan China 2. department of Mathematics and Physics Shandong Institute of Architecture and Engineering 250014 Jinan China

By employing a model potential including the electron exchange energy, we extend the semiclassical closed orbit theory to study the multielectron atoms. Using special region-splitting consistent and iterative method, we figure out the closed orbits in the corresponding classical system and calculate the recurrence spectra of triplet helium atoms in parallel electric and magnetic fields at scaled energy ε=?0.03,n≈40,n=0. The core-scattering effects have been taken into account, which lead to more peaks in the spectra. It has also been confirmed by means of the direct comparison between the spectral portrait in such a plot and those of hydrogen case. In order to compare the theoretic results with experiment, we investigate the closed orbits and recurrence spectra of helium atoms for the similar exchange potential but applied only by single electric field at scaled energy ε=?2.7 case. The spectra are in good agreement with the experimental observation. We conclude that our model is correct and it is necessary to consider the exchange effect for determining the photoabsorption spectra of multielectron atoms in strong external fields.

关键词： exchange potential, recurrence spectra, semiclassical closed orbit theory, core-scattering.

Importance of oxygen-containing functionalities and pore structures of biochar in catalyzing pyrolysis of homologous poplar

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Chinese Journal of Chemical Engineering 2024年第1期65卷 200-211页

作者： li Qiu Chao li Shu Zhang Shuang wang bin li Zhenhua Cui Yonggui Tang Obid Tursunov Xun Hu School of Material Science and Engineering University of JinanJinan 250022China Joint International Research Laboratory of Biomass Energy and Materials College of Materials Science and EngineeringNanjing Forestry UniversityNanjing 210037China School of Energy and Power Engineering Jiangsu UniversityZhenjiang 212013China Shandong BASAN Graphite New Material Plant Zibo 255311China department of Power Supply and Renewable Energy Sources National Research University TIIAMETashkent 100000Uzbekistan

Biochar and bio-oil are produced simultaneously in one pyrolysis process,and they inevitably contact and may interact,influencing the composition of bio-oil and modifying the structure of *** this sense,biochar is an inherent catalyst for *** this study,in order to investigate the influence of functionalities and pore structures of biochar on its capability for catalyzing the conversion of homologous volatiles in bio-oil,three char catalysts(600C,800C,and 800AC)produced via pyrolysis of poplar wood at 600 or 800℃or activated at 800℃,were used for catalyzing pyrolysis of homologous poplar wood at 600℃,*** results indicated that the 600C catalyst was more active than 800C and 800AC for catalyzing cracking of volatiles to form more gas(yield increase by 40.2%)and aromatization of volatiles to form more light or heavy phenolics,due to its abundant oxygen-containing functionalities acting as active *** developed pores of the 800AC showed no such catalytic effect but could trap some volatiles and allow their further conversion via sufficient ***,the interaction with the volatiles consumed oxygen on 600C(decrease by 50%),enhancing the aromatic degree and increasing thermal *** dominance of deposition of carbonaceous material of a very aromatic nature over 800C and 800AC resulted in net weight gain and blocked micropores but formed additional *** in situ diffuse reflectance infrared Fourier transform spectroscopy characterization of the catalytic pyrolysis indicated superior activity of 600C for removal of -OH,while conversion of the intermediates bearing C=O was enhanced over all the char catalysts.

关键词： Poplar wood Catalytic pyrolysis Char catalyst Volatile-char interaction Bio-oil

DNA bridging of FOXP3 ladder-like multimer: Unveiling a novel transcriptional regulation paradigm

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The Innovation 2024年第3期5卷 15-16页

作者： Ying Lu Lanfang li Hanting Yang {1. li Zuoyun wang Key Laboratory of Metabolism and Molecular Medicine of the Ministry of Education Shanghai Xuhui Central Hospital and School of Basic Medical SciencesFudan UniversityShanghai 200032China Institute for Translational Brain Research State Key Laboratory of Medical NeurobiologyMOE Frontiers Center for Brain ScienceDepartment of NeurologyZhongshan HospitalFudan UniversityShanghai 200032China Center for Immune-Related Diseases at Shanghai Institute of Immunology Department of Immunology and MicrobiologyShanghai Jiao Tong University School of MedicineShanghai 200025China

In the latest issue of Nature,Zhang et *** a novel ladder-like structure of FOXP3-DNA interaction involving FOXP3 multimerization and remote DNA bridging through a com{1.ation of biochemistry,structural biology,cell biology,and bioinformatics analyses.1.In this commentary,we highlight their key findings and provide our insights into the research paradigm for further exploration of a novel transcriptional regulation mode as well as a therapeutic strategy from the structural aspects of the FOXP3 complex(Figure 1..

关键词： FOXP3 bridging