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Effect of Quantum Fluctuation on Two-Dimensional Spatially Anisotropic Heisenberg Antiferromagnet with Integer Spin

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Communications in Theoretical Physics 2006年第6期45卷 1137-1146页

作者： JI An-chun TIAN guang-Shan School of Physics Peking University Beijing 100871 China

In the present paper, we calculate the Gaussian correction to the critical value J^c⊥ caused by quantum spin fluctuation in a two-dimensional spatially anisotropic Heisenberg antiferromagnet with integer spin S. Previously, some authors computed this quantity by the mean-field theory based on the Sehwinger boson representation of spin operators. However, for S = 1, their result is much less than the one derived by numerical calculations. By taking the effect of quantum spin fluctuation into consideration, we are able to produce a greatly improved result.

关键词： spatially anisotropic Heisenberg model functional integration Schwinger boson representation

Quantum Phase Transition in Quasi-two-dimensional Heisenberg Antiferromagnet with Single-Ion Anisotropy

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Communications in Theoretical Physics 2007年第1期47卷 171-180页

作者： JI An-chun TIAN guang-Shan School of Physics Peking University Beijing 100871 China

In the present paper, we investigate the quantum phase transition in a spatially anisotropic antiferrornagnetic Heisenberg model of S =1 with single-ion energy anisotropy. By using the Schwinger boson representation, we calculate the Gaussian correction to the critical value J⊥^c caused by quantum spin fluctuations. We find that, for the positive single-ion energy, a nonzero value of J⊥^c is always needed to stabilize the antiferromagnetic long-range order in this model. It resolves a difference among literature and shows clearly that the effect of quantum fluctuations may qualitatively change a result obtained by the mean-field theories on lower-dimensional systems.

关键词： spatially anisotropic Heisenberg model single-ion anisotropy functional integration Schwinger-Boson representation

Ultrahigh performance concrete–properties, applications and perspectives

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Science China(Technological Sciences) 2015年第4期58卷 587-599页

作者： GU chun Ping YE guang SUN Wei School of materials Science & Engineering Southeast University Microlab Faculty of Civil Engineering and Geosciences Delft University of Technology Jiangsu Key Laboratory of Construction materials Collaborative Innovation Center for Advanced Civil Engineering materials

Over the last twenty years,remarkable advances have taken place in the research and application of ultra-high performance concrete(UHPC),which exhibits outstanding mechanical properties and excellent *** has shown great potential for the next generation infrastructure construction from the sustainability point of *** paper will give an overview on UHPC,with particular focus on the properties,applications and *** several decades of development,several types of commercial UHPC materials are available in the market,and the properties of UHPC have been characterized by numerous experimental and field *** speaking,the performance(*** properties and durability)of UHPC is much better than normal concrete(NC)and high performance concrete(HPC).Therefore,the uses of UHPC are growing all over the world,in both fields of new construction and ***,it is still a special material and technology,which is not worldwide *** some application prospects of UHPC are briefly introduced in the paper,and the efforts,which have to be made to turn UHPC into a widespread‘regular’technology,are *** paper aims to help designers,engineers,architects and infrastructure owners to know the capacities of UHPC and thus to increase the applications of this material.

关键词： UHPC characteristics durability applications perspectives

一种高速多通道涡流信号采集系统的设计与实现

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无损检测 2003年第1期25卷 21-24页

作者：高印寒吴定超李春光马羽宽吉林大学测试科学实验中心长春130025 一汽大众汽车有限公司长春130025

在研究分析的基础上 ,介绍一种基于线阵涡流传感器的二维数据采集系统 ,给出了系统原理图和相关器件框图 ,采用的多路模拟选择开关、X R正交分解器和数字信号处理器有效提高了信号采集处理速度。

关键词：涡流检验传感器数字信号处理数据采集

Controlled synthesis and optical properties of Ce^(3+)/Tb^(3+) co-doped BaGdF_5 nanocrystals

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Rare Metals 2015年第9期34卷 673-678页

作者： chun-Yan Cao An Xie Xiao-guang Yu College of mathematics and Physics Jinggangshan University School of materials Science and Engineering Xiamen University of Technology

Based on a hydrothermal method, the Ce3+/Tb3+ co-doped Ba Gd F5 nanocrystals were synthesized by controlling the introduction concentration of Ba2+ and Gd3+. The samples were characterized by X-ray diffraction(XRD), field emission scanning electron microscopy(FESEM) images, photoluminescence(PL) excitation, and emission spectra, as well as the photoluminescence dynamic decay curves. With the increase of the Ba2+ concentration in the synthesis procedure, the positions of diffraction peaks of XRD patterns move toward lower degree, and the case of the samples synthesized with the increase of the Gd3+ concentration is contrary, which consists well with each other. The FE-SEM images suggest that the BaGdF5 nanocrystals are in spherical morphology,and the average diameters decrease with the increase of Ba2+ or Gd3+ concentration. For the 4f–5d transition of Ce3+ is sensitive to the environment of local lattice, the PL excitation and emission spectra of the samples are different. The 4f–4f transition of Tb3+ also presents different optical properties in different host lattices. The variations of the optical properties of Ce3+ and Tb3+ as well as the lifetime of the 5D4+7F5 emission of Tb3+ are also consistent well with each other in the two series of samples.

关键词： Hydrothermal synthesis Optical properties Nanocrys

Monotone Chains in Modulus of Two Classes of Dirichlet Coefficients

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Acta mathematica Sinica,English Series 2023年第6期39卷 1101-1114页

作者： guang Shi Lü Qiang ma School of mathematics Shandong UniversityJi'nan 250100P.R.China

Let f1,...,fkand g1,...,qkbe non-CM newforms of square-free *** byλ_(sym)jf_(i)(n)the coefficients of the Dirichlet expansion of L(sym^(j)f_(i),s)andν1,...,νkthe distinct positive integers such thatλ_(sym)jf_(i)(νi)≠*** this paper,we obtain that there exist infinitely many positive integers m such that 0<λ_(sym)jf_(1)(m+ν1)|<|λ_(sym)jf_(2)(m+ν2)|<…<|λ_(sym)jf_(k)(m+νk)|.For coefficients of the Dirichlet expansion of L(sym^(j1)f×sym^(j2)g,s),we have a similar result.

关键词： Dirichlet coefficients Sato-Tate conjecture

Tea consumption and risk of stroke:a dose-response meta-analysis of prospective studies

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2012年第8期13卷 652-662页

作者： Li SHEN Liu-guang SONG Hong ma chun-na JIN Jian-an WANG Mei-xiang XIANG Department of Cardiology the Second Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhou 310009China Cardiovascular Key Lab of Zhejiang Province the Second A3filiated HospitalSchool of MedicineZhejiang UniversityHangzhou 310009China

Objective:To determine the association between tea consumption and the risk of stroke. Methods:We searched the PubMed database from January 1966 to march 2012 and reviewed reference lists of retrieved articles to identify relevant studies. Studies were included if they reported relative risks (RRs) and corresponding 95% confidence intervals (CIs) of stroke with respect to three or more categories of tea consumption. A random-effects model was used to combine the study-specific risk estimates. Results:Fourteen studies, consisting of 513 804 participants with a median follow-up of 11.5 years, were included in this meta-analysis. We observed a modest but statistically significant inverse association between tea consumption and risk of stroke. An increase of three cups/d in tea consumption was associated with a 13% decreased risk of stroke (RR 0.87; 95% CI, 0.81-0.94). The decreased risk of stroke with tea consumption was consistent among most subgroups. Based on the three studies that provided results for stroke subtypes, tea consumption was also inversely associated with the risk of ischemic stroke (RR 0.76; 95% CI, 0.69-0.84), but not cerebral hemorrhage (RR 0.96; 95% CI, 0.82-1.11) or subarachnoid hemorrhage (RR 0.81; 95% CI, 0.57-1.16). Conclusions:Tea consumption is associated with a decreased risk of stroke, particularly ischemic stroke. More well-designed, rigorously conducted studies are needed in order to make confident conclusions about the association between tea consumption and stroke subtypes.

关键词： Tea Stroke Prospective studies Dose-response meta-analysis

A Middle Triassic stem-neopterygian fish from China sheds new light on the peltopleuriform phylogeny and internal fertilization

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Science Bulletin 2016年第22期61卷 1766-1774页

作者： guang-Hui Xu Xin-Ying ma Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences

Internal fertilization and viviparity are easily observed and well studied in living neopterygian fishes(14teleostean families), but they are difficult to identify in extinct taxa due to the limitation of the fossil record. The Peltopleuriformes from the Middle to Late Triassic of Europe and South China are a stem group of Neopterygii that may have first evolved internal fertilization and viviparity in this clade because they show a highly modified anal fin in presumed males resembling the intromittent organ in living viviparous teleosts. Until recently, Peltopleurus lissocephalus and P. rugosus from the Ladinian/Anisian boundary(*242 ma) of Monte San Giorgio area in Switzerland and Italy represent the oldest record of Peltopleuriformes, and the phylogenetic interrelationships of this group remain controversial. Here, we report the discovery of a new peltopleuriform, Peltopleurus nitidus sp. nov., based on eleven well-preserved specimens from the early Middle Triassic(Pelsonian, Anisian, *244 ma)of Luoping, eastern Yunnan, China. The discovery documents the oldest convincing peltopleuriform, extending the geological range of this clade by proximately two million years. Results of the phylogenetic analysis recover *** at the base of Peltopleuridae, and provide robust support for the sister-group relationships of Peltopleuridae with Thoracopteridae within the Peltopleuriformes. The male anal fin of P. nitidus shows a primitive condition unknown in other peltopleuriforms. Comparative studies of the male anal fin in P. nitidus and other peltopleuriforms shed new light on the internal fertilization in this group.

关键词： Sexual dimorphism Viviparity Peltopleuridae Thoracopteridae Triassic

Tebufenozide resistance is associated with sex-linked inheritance in Plutella xylostella

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Insect Science 2015年第2期22卷 235-242页

作者： guang-chun Cao Zhao-Jun Han Entomology Department/Key Laboratory of Monitoring and management of Plant Diseases and Insects Ministry of Agriculture NanjingAgricultural University Nanjing State Key Laboratory for Biology of Plant Disease and Insect Pests Institute of Plant ProtectionChinese Academy of Agricultural Sciences Beijing China

The diamondback moth （DBM）, Plutella xylostella （L.）, is a major pest of cruciferous crops. Tebufenozide, a novel nonsteroidal ecdysone agonist, exhibits good efficacy and has played an increasingly important role in the control of Lepidopteran pests in China. For its resistance management, the genetic basis of tebufenozide resistance was studied using a laboratory selected resistant strain of DBM （resistant ratio, RR = 268）. A series of crosses with laboratory susceptible and resistant strains revealed that tebufenozide resistance in this pest was partially biased toward female heredity, with a large difference in RR for F1 （RR = 29） and rF1 progeny （RR = 147）. The dominance calculated for these 2 cross progeny was -0.788 and 0.09, respectively. Further analysis showed that the susceptible male and female larvae were similar in theft sensitivity to tebufenozide, but the resistant female larvae showed significantly higher resistance than the resistant male larvae. The heredity of tebufenozide resistance in DBM might be linked with the W sex chromosome, which suggested that DBM has the ability to develop high levels of resistance to tebufenozide. This is the first report of sex-linked inheritance oftebufenozide resistance in P xylostella （L.）.

关键词： insecticide resistance Plutella xylostella sex linkage tebufenozide