检索结果-南通市图书馆

Rainbow Pancyclicity in a Collection of Graphs Under the Dirac-type Condition

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2024年第2期40卷 269-274页

作者： Lu-yi li ping li xue-liang li Center for Combinatorics and LPMC Nankai UniversityTianjin 300071China School of Mathematics and Statistics Shaanxi Normal UniversityXi’an 710062China

Let G={Gi:i∈[n]} be a collection of not necessarily distinct n-vertex graphs with the same vertex set V,where G can be seen as an edge-colored(multi)graph and each Gi is the set of edges with color i.A graph F on V is called rainbow if any two edges of F come from different Gis’.We say that G is rainbow pancyclic if there is a rainbow cycle Cℓof lengthℓin G for each integerℓ2[3,n].In 2020,Joos and Kim proved a rainbow version of Dirac’s theorem:Ifδ(Gi)≥2/n for each i∈[n],then there is a rainbow Hamiltonian cycle in *** this paper,under the same condition,we show that G is rainbow pancyclic except that n is even and G consists of n copies of Kn/2,n/*** result supports the famous meta-conjecture posed by Bondy.

关键词： rainbow Hamiltonian cycle rainbow pancyclic meta-conjecture

同方期刊数据库

Dual Z-scheme Bi_(3)TaO_(7)/Bi_(2)S_(3)/SnS_(2)photocatalyst with high performance for Cr(Ⅵ)reduction and TC degradation under visible light irradiation

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2022年第7期41卷 2417-2428页

作者： Jing-Jing Xu Hao-Yu Gu Min-Dong Chen xue-ping li Hong-Wen Zhao Hong-Bin Yang Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Nanjing 210044China Collaborative Innovation Center of Atmospheric Environment and Equipment Technology Nanjing 210044China Jiangsu Engineering Technology Research Center of Environmental Cleaning Materials Nanjing 210044China School of Environmental Science and Engineering Nanjing University of Information Science and TechnologyNanjing 210044China Nanyang Technological University Singapore 639798Singapore

Ternary direct dual Z-scheme Bi_(3)T_(a)O_(7)/Bi_(2)S_(3)/SnS_(2) photocatalyst was successfully prepared by hydrothermal *** composite photocatalysts exhibited high photocatalytic performance on both Cr(Ⅵ)reduction and tetracycline(TC)degradation under the irradiation of visible *** results manifested that the photogenerated charge transfer efficiency was improved after forming the dual Z-scheme *** a result,the composite catalysts exhibited higher photocat-alytic degradation efficiency than the corresponding single *** apparent rate constant(k)value of the best sample BBS-3 for TC degradation was 0.0403 min^(-1),which was 40 times,8 times,and 18 times higher than that of single *** the k value of BBS-3 for the Cr(Ⅵ)reduction was 0.0249 min^(-1),it was about 23 times,7 times,and 18 times that of single *** experiments indicated that the BBS-3 had good photocat-alytic ***,the possible mechanism on Cr(Ⅵ)reduction and TC degradation was proposed based on the experimental results.

关键词： Photocatalysis Dual Z-scheme Heterojunction Heavy metal Organic pollutant

Effect of Bimodal Quasicrystal Phase on the Dynamic Recrystallization of Mg–Zn–Gd Alloy during High-Pressure Torsion

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2024年第7期37卷 1128-1134页

作者： ping li Shuangwu Xia Junfu Dong liangwei Dai Zhicheng Luo Kemin xue School of Material Science and Engineering Hefei University of TechnologyHefei230009China

The Mg–Zn–Gd alloy with quasicrystal icosahedral phase was processed by high-pressure torsion (HPT). The effect of bimodal I-phase on the dynamic recrystallization was analyzed by transmission electron microscopy. The results showed that the block I-phase can stimulate obvious particle-stimulated nucleation and dynamic recrystallization (DRX) grains were preferentially formed after HPT for 5 turns, while the granular I-phase only promoted the generation of sub-grains. The orientation relationship was determined as twofold//[1210] and fivefold//(0002)_(Mg). Moreover, after HPT for 9 turns, the DRX grains induced by block I-phase appeared to grow up and coarsened. Compared with block I-phase, the grains induced by granular I-phase presented much smaller size and distributed more homogeneous due to the strong pinning effect.

关键词： High-pressure torsion(HPT)-Quasicrystal phase Dynamic recrystallization Particle-stimulated nucleation Orientation relationship

Influence of pressure disturbance wave on dynamic response characteristics of liquid film seal for multiphase pump

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2024年第3期21卷 2048-2065页

作者： Qing-ping li Jin-Ya Zhang Jia-Xiang Zhang Yong-xue Zhang CNOOC Research Institute Company limited State Key Laboratory of Natural Gas Hydrate College of Mechanical and Transportation Engineering China University of Petroleum

Slug flow or high GVF(Gas Volume Fraction) conditions can cause pressure disturbance waves and alternating loads at the boundary of mechanical seals for multiphase pumps, endangering the safety of multiphase pump units. The mechanical seal model is simplified by using periodic boundary conditions and numerical calculations are carried out based on the Zwart-Gerber-Belamri cavitation model. UDF(User Define Function) programs such as structural dynamics equations, alternating load equations, and pressure disturbance equations are embedded in numerical calculations, and the dynamic response characteristics of mechanical seal are studied using layered dynamic mesh technology. The results show that when the pressure disturbance occurs at the inlet, as the amplitude and period of the disturbance increase, the film thickness gradually decreases. And the fundamental reason for the hysteresis of the film thickness change is that the pressure in the high-pressure area cannot be restored in a timely manner. The maximum value of leakage and the minimum value of axial velocity are independent of the disturbance period and determined by the disturbance amplitude. The mutual interference between enhanced waves does not have a significant impact on the film thickness, while the front wave in the attenuated wave has a promoting effect on the subsequent film thickness changes, and the fluctuation of the liquid film cavitation rate and axial velocity under the attenuated wave condition deviates from the initial values. Compared with pressure disturbance conditions, alternating load conditions have a more significant impact on film thickness and leakage. During actual operation, it is necessary to avoid alternating load conditions in multiphase pump mechanical seals.

关键词： Multiphase pump liquid film seal Pressure disturbance wave Dynamic response characteristics

Synthesis, Structure and Luminescence Property of a New Two-dimensional Znic(Ⅱ) Coordination Polymer

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2020年第7期39卷 1295-1300页

作者： xue li-ping DING Ke-Xin College of Food and Drug Luoyang Normal UniversityLuoyang 471934China College of Chemistry and Chemical Engineering Luoyang Normal UniversityLuoyang 471934China

Based on 5-dimethylamino-isophthalic acid(H2dia)and 1,2-bis(4-pyridyl)ethylene(bpe)mixed linkers,a new d10-configuration Zn(Ⅱ)coordination polymer material,[Zn(dia)(bpe)(H2O)]n(1),was *** the asymmetric unit,there are one Zn2+ion,two dia2-anions,one neutral bpe linker and one free H2O *** the complex,adjacent Zn2+ions are alternately bridged by the dia2-dianions to generate chains which are further connected by flexible bpe ligands to form a two-dimensional(2 D)layer *** topology,the structure of 1 represents a non-interpenetrating 4-connected sql ***,infrared spectroscopy,elemental analyses,thermogravimetric analysis,powder X-ray diffraction,solid UV-Vis absorption spectra and photoluminescent property of 1 are also investigated.

关键词： Zn coordination polymer crystal structure 5-dimethylamino-isophthalic acid 1,2-bis(4-pyridyl)ethylene UV-Vis absorption spectra luminescence property

Doping engineering of iron oxide nanoparticles towards high performance and biocompatible T_(1)-weighted MRI contrast agents

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第1期43卷 298-308页

作者： xue Xu ping-li Dong Yu-Yun Chai Run Yang Zhen-Hui Ma Chi-Chong Lu Department of Chemistry College of Chemistry and Materials EngineeringBeijing Technology and Business UniversityBeijing 100048China Department of Physics Beijing Technology and Business UniversityBeijing 100048China

Extremely small-sized iron oxide nanoparticles(IONPs) are of great interest in magnetic resonance imaging(MRI) due to their biosafety as an alternative to clinical gadolinium(Ⅲ) complexes-based contrast *** when the particle size is less than 10 nm,it has strong diffusion ability and deep penetration distance in tumor *** doping can significantly enhance the T_(1)contrast effect of nanoparticles by regulating the surface exposed ***,the nucleation and growth processes of multi-component synthesis systems are complex and difficult to be accurately controlled,leading to great challenges in the synthesis of ultra-small-sized nanoparticles with different components and ***,extremely smallsized superparamagnetic gadolinium-doped iron oxide nanoparticles(GdIONPs,Gd_(x)Fe_(3-x)O_(4) NPs) with adjustable doping amount and controllable size in the range of 3.5-7.5 nm were synthesized by thermal ***,as-synthesized GdIONPs were surface modified with a highly water-soluble and biocompatible carboxyl-polyethylene glycol-phosphoric acid ligand with high binding ***_(0.65)Fe_(2.35)O_(4) NPs exhibited very high r_(1) relaxivity of 10.6 mmol^(-1)·L·s^(-1) in terms of all metal concentrations and 49.0 mmol^(-1)·L·s^(-1) in terms of gadolinium alone,respectively,3 and 14 times higher than clinical T_(1) contrast agents(Gd-DTPA).GdIONPs can continuously obtain high resolution images of blood vessels,and can be used as an efficient and multifunctional contrast agent for MR T_(1)*** stable and efficient doping strategy provides an easy and effective method to individually optimize the magnetic properties of complex oxides and their relaxation effects for a variety of biomedical applications.

关键词： Iron oxide nanoparticles Small size Magnetic resonance imaging Substitutional doping Gd dopant

Optimization of time-delayed feedback control of seismically excited building structures

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第3期9卷 330-337页

作者： xue-ping li Wei-qiu ZHU Zu-guang YING Department of Mechanics School of Aeronautics and Astronautics State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China

An optimization method for time-delayed feedback control of partially observable linear building structures subjected to seismic excitation is proposed. A time-delayed control problem of partially observable linear building structure under horizontal ground acceleration excitation is formulated and converted into that of completely observable linear structure by using separation principle. The time-delayed control forces are approximately expressed in terms of control forces without time delay. The control system is then governed by It? stochastic differential equations for the conditional means of system states and then transformed into those for the conditional means of modal energies by using the stochastic averaging method for quasi-Hamiltonian systems. The control law is assumed to be modal velocity feedback control with time delay and the unknown control gains are determined by the modal performance indices. A three-storey building structure is taken as example to illustrate the proposal method and the numerical results are confirmed by using Monte Carlo simulation.

关键词：最优化设计建筑结构建筑物控制方法

Two sandwich-type uranyl-containing polytungstates catalyze aerobic synthesis of benzimidazoles

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第3期43卷 1316-1322页

作者： Yu-Feng liu Qi-Long Hu xue-Jiao Chen Ke li Pei Luo Guo-ping Yang School of Chemistry and Material Science Jiangxi Province Key Laboratory of Synthetic ChemistryJiangxi Key Laboratory for Mass Spectrometry and InstrumentationEast China University of TechnologyNanchang330013China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen518055China

Diversified synthetic strategies are extremely important for the structural diversity of uranium-containing polyoxometalates(U-POMs)and their functional ***,two sandwich-type U-POMs were reported,which are Na_(5.6)K_(6.4)[(UO_(2))(H_(2)O)(TeW_(9)O_(33))]_(2)·21H_(2)O(UTeW_(9))and Na_(8.9)K_(2.7)H_(1.19)[K_(0.79)(UO_(2))_(2.21)(PW_(9)O_(34))_(2)]·12H_(2)O(UPW_9)using in-situ strategy and lacunary precursor strategy,***_9 shows a typical Keggin-typeopen or half-sandwich configuration.

关键词： configuration expansion sandwich

Synthesis, Crystal Structure and Luminescence of a Cadmium(Ⅱ) Coordination Polymer with 3,6-Connected rtl Topology

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2016年第2期35卷 293-297页

作者： xue li-ping SHAN li-li FENG Wen-Jing College of Chemistry and Chemical Engineering Luoyang Normal University

A new cadmium（Ⅱ） coordination polymer,[Cd（Hcna）2]n（1）,was hydrothermally synthesized based on 5-（4-carboxyphenoxy）nicotinic acid（H2cna） organic linker.X-ray singlecrystal diffraction determination reveals that 1 crystallizes in the monoclinic P21/c space group,with a = 10.101（2）,b = 7.9139（17）,c= 15.627（3） A,β= 103.364（3）°,V= 1215.4（4） A^3,Z=2,Mr= 628.81,Dc = 1.718 Mg/m^3,μ= 0.963 mm^（-1）,F（000） = 628,the final R = 0.0177 and wR = 0.0432 for 2263 observed reflections with I 〉2σ（I）.In 1,the Cd（Ⅱ） cations are connected by nicotiniate units to form a two-dimensional（2D） layer,and it is further linked through benzoate units to form a three-dimensional（3D） ***,the structure of 1 represents a 3,6-connected 3D rtl ***,thermal stability and photoluminescent property of 1 have also been investigated.

关键词： cadmium coordination polymer crystal structure 5-(4-carboxyphenoxy)nicotinic acid rtl topology luminescence