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NiS ultrafine nanorod with translational and rotational symmetry

National Science Review 2024年第7期11卷 218-225页

作者： Jianxin Kang Qi Hu Ruixuan Zhang Ang Gao Zhongning Huang Ziming Su Ke Pei Qinghua Zhang li-min liu Renchao Che lin Gu Er-Jia Guo lin Guo School of Chemistry Beihang University Laboratory of Advanced Materials Shanghai Key Lab of Molecular Catalysis and Innovative Materials Academy for Engineering&Technology Fudan University Zhejiang Laboratory Beijing National Center for Electron Microscopy and Laboratory of Advanced Materials School of Materials Science and Engineering Tsinghua University Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences School of Physics Beihang University

Anisotropy is a significant and prevalent characteristic of materials, conferring orientation-dependent properties, meaning that the creation of original symmetry enables key functionality that is not found in nature. Even with the advancements in atomic machining, synthesis of separated symmetry in different directions within a single structure remains an extraordinary challenge. Here, we successfully fabricate NiS ultrafine nanorods with separated symmetry along two directions. The atomic structure of the nanorod exhibits rotational symmetry in the radial direction, while its axial direction is characterized by divergent translational symmetry, surpassing the conventional crystalline structures known to date. It does not fit the traditional description of the space group and the point group in three dimensions, so we define it as a new structure in which translational symmetry and rotational symmetry are separated. Further corroborating the atomic symmetric separation in the electronic structure, we observed the combination of stripe and vortex magnetic domains in a single nanorod with different directions, in accordance with the atomic *** manipulation of nanostructure at the atomic level introduces a novel approach to regulate new properties finely, leading to the proposal of new nanotechnology mechanisms.

关键词： separated symmetry NiS anisotropy structure atomic machining magnetic domain

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Preparation and catalytic activity of CO-resistant catalyst core-shell Au@Pt/C for methanol oxidation

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Rare Metals 2012年第5期31卷 451-456页

作者： FENG Rongjuan li min liu Jiaxiang College of Materials Science and Engineering Laboratory of Electrochemical Process and Technology for Materials Beijing University of Chemical Technology Beijing 100029 China

Au@Pt core-shell nanoparticles were successfully synthesized by a successive reduction method and then assembled on Vulcan XC-72 carbon surface. Furthermore, its composition, morphology, structure, and activity towards methanol oxidation were characterized by UV-vis spectrometry, transmission electron microscopy (TEM), high-resolution TEM (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV). Results reveal that Au@Pt/C catalyst has better activity towards methanol oxidation than the pure platinum prepared under the same conditions. When the atomic ratio of Au to Pt in the prepared Au@Pt/C catalyst is 1:2, this catalyst exhibits best electrocatalytic activity towards methanol oxidation in acidic media, and the peak current density on this catalyst is ~2.0 times higher than that on Pt/C catalyst. The better catalytic activity of Au@Pt/C results from its better resistance to toxic CO than Pt/C because the CO oxidation on Au@Pt/C is 60 mV more negative than the case on Pt/C. © The Nonferrous Metals Society of China and Springer-Verlag Berlin Heidelberg 2012.

关键词： Carbon Cobalt Cyclic voltammetry Electrocatalysts Gold Methanol Nanoparticles Oxidation Photoelectrons Platinum Platinum alloys Synthesis (chemical) Transmission electron microscopy X ray diffraction X ray photoelectron spectroscopy

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Removal of airborne microorganisms emitted from a wastewater treatment oxidation ditch by adsorption on activated carbon

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Journal of Environmental Sciences 2011年第5期23卷 711-717页

作者： lin li min Gao Junxin liu Xuesong Guo Department of Water Pollution Control Technology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

Bioaerosol emissions from wastewater and wastewater treatment processes are a significant subgroup of atmospheric aerosols. Most previous work has focused on the evaluation of their biological risks. In this study, however, the adsorption method was applied to reduce airborne microorganisms generated from a pilot scale wastewater treatment facility with oxidation ditch. Results showed adsorption on granule activated carbon （GAC） was an efficient method for the purification of airborne microorganisms. The GAC itself had a maximum adsorption capacity of 2217 CFU/g for airborne bacteria and 225 CFU/g for fungi with a flow rate of 1.50 m^3/hr. Over 85% of airborne bacteria and fungi emitted from the oxidation ditch were adsorbed within 80 hr of continuous operation mode. Most of them had a particle size of 0.65-4.7 μm. Those airborne microorganisms with small particle size were apt to be adsorbed. The SEM/EDAX, BET and Boehm＇s titration methods were applied to analyse the physicochemical characteristics of the GAC. Relationships between GAC surface characteristics and its adsorption performance demonstrated that porous structure, large surface area, and hydrophobicity rendered GAC an effective absorber of airborne microorganisms. Two regenerate methods, ultraviolet irradiation and high pressure vapor, were compared for the regeneration of used activated carbon. High pressure vapor was an effective technique as it totally destroyed the microorganisms adhered to the activated carbon. Microscopic observation was also carried out to investigate original and used adsorbents.

关键词： activated carbon adsorption airborne microorganisms oxidation ditch wastewater treatment facility

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Incidence of cilioretinal arteries in Chinese Han population

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International Journal of Ophthalmology(English edition) 2011年第3期4卷 323-325页

作者： Lei liu li-min liu and Lei Chen Department of Ophthalmology the First Affiliated Hospital China Medical University. Shenyang 110001 Liaoning Province China

AIM: To estimate the incidence of cilioretinal arteries among Han population of north China. METHODS: A cross-sectional sample of subjects aged from 20 years old to 80 years old were selected using a cluster sampling technique from Shenyang of liaoning Province for Diabetic Eye Disease Study. Eligible subjects were recruited in the Community Health Center which took the stereo fundus photography using 45 degrees Non-Mydriatic Fundus Camera. Data were analyzed by SPSS 14.0. RESULTS: The incidence of cilioretinal arteries in 5000 eyes of 2500 subjects was determined. One, two or more cilioretinal arteries were present in 876 of all subjects and in 923 of all the eyes. Difference of presence, number and distribution of cilioretinal arteries was observed. During the subjects, the arteries occurred bilaterally in 6.9% and contributed to some portion of the temporal circulation in 78.3%, nasal circulation 14.8%, respectively. Statistical analysis indicated that there was no significant difference in incidence between men and women, left and right eyes (P>0.05). CONCLUSION: 35.0% persons have the cilioretinal arteries in Han population of north China. Men and women have an equal distribution of cilioretinal arteries.

关键词： cilioretinal artery incidence population

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Explicit Piecewise Smooth Solutions of Landau-lifshitz Equation with Discontinuous External Field

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Acta Mathematicae Applicatae Sinica 2009年第1期25卷 61-74页

作者： Gan-shan Yang Yun-zhang Zhang li-min liu Institute of Mathematics Science Yunnan Normal University Kunming 650092 China Department of Mathematics Yunnan National University Kunming 650031 China Faculty of Science Xi'an Jiaotong University Xi'an 710049 China College of Mathematics and Physics Chongqing University Chongqiong 400030 China

In this paper, we shall construct some explicit piecewise smooth （global continuous） solutions as well as blow up solutions to the multidimensional Landau-lifshitz equation, subject to the external magnetic fields being both discontinuous and unbounded. When the external magnetic field is continuous, some explicit exact smooth solutions and blow up solution are also constructed. We also establish some necessary and sufficient conditions to ensure that the solution of multidimensional Landau-lifshitz equation with external magnetic field converges to the solution of equation without external magnetic field when the external magnetic field tends to zero.

关键词： Multidimensional Landau-lifshitz equation discontinuous external field piecewise smoothsolution

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High-quality manufacturing method ofcomplicated castings based on multi-materialhybrid moulding process

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China Foundry 2018年第5期15卷 343-350页

作者： li-min liu Zhong-de Shan Feng liu Dun Lan State Key Laboratory of Advanced Forming Technologyand EquipmentChina Academy of Machinery Science and Technology Group Co.Ltd.Beijing 100083China

A multi-material hybrid patternless moulding process for complicated castings has been proposed. Moulding sands used in the hybrid moulding process include silica sand, ceramic sand, chromite sand, zircon sand, and steel shot sand. Experimental method was used to study the effects of moulding sands on the temperature field, mechanical properties, and dimensional precision of the iron castings. Under the condition that the wall thickness on different sides of the casting is the same, when the wall thickness is greater than 10 mm, the heat storage capacity of the moulding sands from strong to weak is steel shot sand, zircon sand, chromite sand, ceramic foundry sand, and silica sand. Tensile strength of the obtained castings from high to low is zircon sand, chromite sand, steel shot sand, ceramic sand, and silica sand. Contraction rate of the obtained castings from high to low is steel shot sand, zircon sand, chromite sand, silica sand, and ceramic sand. Therefore, steel shot sand and zircon sand can be used as chilled sand, and even can be used instead of cold iron when the casting wall thickness is greater than 10 mm. Zircon sand and chromite sand can be used to obtain high mechanical properties, and silica sand and ceramic sand can be selected to obtain high dimensional precision of the castings. Finally, a typical iron casting piece was tested by experiment using the hybrid moulding process. Excellent performances of iron castings confirm the feasibility of the hybrid moulding process.

关键词： hybrid patternless moulding process hybrid moulding process thermal physical parameters temperature field mechanical properties dimensional precision

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Synthesis and catalytic properties of hierarchical TS-1 in the presence of cationic organosilane surfactant

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Chinese Chemical Letters 2011年第3期22卷 303-305页

作者： Shu Shuang li An Feng Zhang min liu Xin Wen Guo State Key Lab of Fine Chemicals School of Chemical Engineering Dalian University of Technology Dalian 116012 China

Hierarchical TS-1 has been synthesized in the presence of cationic organosilane *** material is characterized with XRD,TEM,N_2 adsorption *** results show that the hierarchical TS-1 aggregates consist of small primary units with sizes of 20-30 *** BET surface area increases from 420 to 513 m^2/g compared to conventional TS-1 *** sample is shown to be more active in epoxidation of cyclohexene than conventional TS-1.

关键词： Cationic organosilane surfactant Hierarchical TS-1 Cyclohexene

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Meta-analysis of brain activation in depressive patients with emotional perception disorders

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Neural Regeneration Research 2011年第31期6卷 2429-2434页

作者： Chenwang Jin ming Zhang Dan li Shaohui Ma Yuan Wang min li lihua liu Medical Imaging Center First Hospital of Xi＇an Jiaotong University Xi＇an 710061 Shaanxi Province China

OBJECTIVE：To elucidate the distribution of abnormally activated brain regions in depressive patients during emotional perception processing using activation likelihood estimation,a quantitative meta-analytic *** SOURCES：Computer-based online retrieval was conducted using the PscyINFO,Pubmed and CNKI databases,searching literature from the establishment of each database until June *** SELECTION：Inclusion criteria：（1） studies examined emotion perception tasks using func-tional magnetic resonance imaging; （2） studies indicated regional brain activation abnormalities in depressive patients compared with controls in standard Talairach or MNI *** analyzed coordinates based on the MNI system were converted to Talairach space with icbm2tal *** map of activation likelihood estimation was finally created through the Gaussian smooth （full-width half-maximum=8 mm）,permutation test and corrected for multiple comparisons using the false discovery rate method （q=0.05） with Ginger-ALE 2.0 *** OUTCOME MEASURES：Activation of brain regions in ***：Seventeen studies were identified,involving a total of 261 patients,273 healthy controls and 201 ***-analysis revealed a dysfunctional emotion regulation loop in depressive patients,comprised of the prefrontal cortex,the basal ganglia and the limbic lobe,in which the amygdala was a key *** emotion processing,the left prefrontal cortex and basal ganglia were hy-poactive among depressive patients,whereas the opposite change was found in the limbic ***：Abnormal connections among the prefrontal cortex,basal ganglia and limbic lobe may be involved in the pathophysiology of depressive disorder.

关键词： depression functional magnetic resonance imaging emotional perception disorder prefrontal cortex basal ganglia limbic lobe meta-analysis

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An Approximation Algorithm Based on Seeding Algorithm for Fuzzy k-Means Problem with Penalties

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Journal of the Operations Research Society of China 2024年第2期12卷 387-409页

作者： Wen-Zhao liu min li School of Mathematics and Statistics Shandong Normal UniversityJinan 250014ShandongChina

As a classic NP-hard problem in machine learning and computational geometry,the k-means problem aims to partition the given dataset into k clusters according to the minimal squared Euclidean *** from k-means problem and most of its variants,fuzzy k-means problem belongs to the soft clustering problem,where each given data point has relationship to every center *** to fuzzy k-means problem,fuzzy k-means problem with penalties allows that some data points need not be clustered instead of being paid *** this paper,we propose an O(αk In k)-approximation algorithm based on seeding algorithm for fuzzy k-means problem with penalties,whereαinvolves the ratio of the maximal penalty value to the minimal ***,we implement numerical experiments to show the effectiveness of our algorithm.

关键词： Approximation algorithm Seeding algorithm Fuzzy k-means problem with penalties

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Computational energy materials

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Progress in Natural Science:Materials International 2019年第3期29卷 245-246页

作者： Xin-Gao Gong Xing-Qiu Chen li-min liu Fudan University Institute of Metal Research Chinese Academy of Science School of Physics Beihang Univesity

Due to the rapid development of both the algorithms and high-performance computing (HPC) hardware,Computational Materials Science (CMS),which embraces physics,chemistry,computer science,and other fields,has become one of the most fascinating and fastest growing subjects of the past *** 2011 and 2017,the USA and China launched the Materials Genome Initiative (MGI),which not only boosted the development of CMS,but

关键词： Computational energy materials CMS

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