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Nodal superconducting gap in LiFep revealed by NMR:Contrast with LiFeAs

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Chinese physics B 2021年第4期30卷 113-118页

作者： A F Fang R zhou H Tukada J Yang z Deng X C Wang C Q Jin guo-Qing zheng Department of physics Beijing Normal UniversityBeijing 100875China Institute of physics Chinese Academy of Sciencesand Beijing National Laboratory for Condensed Matter PhysicsBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China Department of physics Okayama UniversityOkayama 700-8530Japan

Identifying the uniqueness of Fep-based superconductors may shed new lights on the mechanism of superconductivity in ***,we report nuclear magnetic resonance(NMR) studies on LiFep and LiFeAs which have the same crystal structure but different pnictogen *** NMR spectrum is sensitive to inhomogeneous magnetic fields in the vortex state and can provide the information on the superconducting pairing symmetry through the temperature dependence of London penetration depth λ_(L).We find that λ_(L) saturates below T~0.2 T_(C) in LiFeAs,where T_(C) is the superconducting transition temperature,indicating nodeless superconducting ***,by using a two-gaps model,we simulate the temperature dependence of λ_(L) and obtain the superconducting gaps of LiFeAs,as Δ_(1)=1.2 kB T_(C) and Δ_(2)=2.8 k_(B)T_(C),in agreement with previous result from spin-lattice *** LiFep,in contrast,λ_(L) does not show any saturation down to T~0.03 T_(C),indicating nodes in the superconducting gap ***,we demonstrate that strong spin fluctuations with diffusive characteristics exist in LiFep,as in some cuprate high temperature superconductors.

关键词： iron-based superconductor nuclear magnetic resonance superconducting pairing symmetry spin fluctuations

Below-Cloud Aerosol Scavenging by Different-Intensity Rains in Beijing City

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Journal of Meteorological Research 2019年第1期33卷 126-137页

作者： Tian LUAN Xueliang guo Tianhang zHANG Lijun guo State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological Administration Key Laboratory for Cloud physics Chinese Academy of Meteorological SciencesChina Meteorological Administration Collaborative Innovation Center for Meteorological Disasters Forecast Early Warning and AssessmentNanjing University of Information Science &Technology National Meteorological Center China Meteorological Administration

Below-cloud aerosol scavenging process by precipitation is important for cleaning the polluted aerosols in the atmosphere, and is also a main process for acid rain formation. However, the related physical mechanism has not been well documented and clarified yet. In this paper, we investigated the below-cloud pM_(2.5)(particulate matter with aerodynamic diameter being 2.5 μm or less) scavenging by different-intensity rains under polluted conditions characterized by high pM_(2.5) concentrations, based on in-situ measurements from March 2014 to July 2016 in Beijing city. It was found that relatively more intense rainfall events were more efficient in removing the polluted aerosols in the atmosphere. The mean pM_(2.5) scavenging ratio and its standard deviation(SD) were 5.1% ± 25.7%, 38.5% ± 29.0%,and 50.6% ± 21.2% for light, moderate, and heavy rain events, respectively. We further found that the key impact factors on below-cloud pM_(2.5) scavenging ratio for light rain events were rain duration and wind speed rather than raindrop size distribution. However, the impacts of rain duration and wind speed on scavenging ratio were not important for moderate and heavy rain events. To our knowledge, this is the first statistical result about the effects of rain intensity, rain duration, and raindrop size distribution on below-cloud scavenging in China.

关键词： pM2.5 below-cloud scavenging rain intensity impact factors

Finite Groups with Seminormal Sylow Subgroups

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Acta Mathematica Sinica,English Series 2008年第10期24卷 1751-1757页

作者： Wen Bin guo Department of Mathematics Xuzhou Normal University Xuzhou 221116 P. R. China Department of Mathematics University of Science and Technology of China Hefei 230026 P. R. China

In this paper, we prove the following theorem： Let p be a prime number, P a Sylow psubgroup of a group G and π = π（G）／ {p}. If P is seminormal in G, then the following statements hold： 1） G is a p-soluble group and P＇ ≤ Op（G）; 2） lp（G） ≤ 2 and lπ（G） ≤ 2; 3） if a π-Hall subgroup of G is q-supersoluble for some q ∈ π, then G is q-supersoluble.

关键词： finite groups seminormal subgroups Sylow subgroups p-soluble groups p-supersoluble groups

On the Fluid Approximation for a Multiclass Queue under Non-preemptive SBp Service Discipline

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Acta Mathematica Sinica,English Series 2012年第2期28卷 379-404页

作者： Yong Jiang guo School of Science Beijing University of Posts and TelecommunicationsBeijing 100876P.R.China

A multi-class single server queue under non-preemptive static buffer priority （SBp） service discipline is considered in this paper. Using a bounding technique, we obtain the fluid approximation for the queue length and busy time processes. Furthermore, we prove that the convergence rate of the fluid approximation for the queue length and busy time processes is exponential for large N. Additionally, a sufficient condition for stability is obtained.

关键词： Multi-class queue non-preemptive SBp service discipline fluid approximation stability,exponential rate of convergence

A Full Asymptotic Series of European Call Option prices in the SABR Model with Beta = 1

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Applied Mathematics 2019年第6期10卷 485-512页

作者： z. guo H. Schellhorn Claremont Graduate University Claremont California USA

We develop two new pricing formulae for European options. The purpose of these formulae is to better understand the impact of each term of the model, as well as improve the speed of the calculations. We consider the SABR model (with β=1) of stochastic volatility, which we analyze by tools from Malliavin Calculus. We follow the approach of Alòs et al. (2006) who showed that under stochastic volatility framework, the option prices can be written as the sum of the classic Hull-White (1987) term and a correction due to correlation. We derive the Hull-White term, by using the conditional density of the average volatility, and write it as a two-dimensional integral. For the correction part, we use two different approaches. Both approaches rely on the pairing of the exponential formula developed by Jin, peng, and Schellhorn (2016) with analytical calculations. The first approach, which we call “Dyson series on the return’s idiosyncratic noise” yields a complete series expansion but necessitates the calculation of a 7-dimensional integral. Two of these dimensions come from the use of Yor’s (1992) formula for the joint density of a Brownian motion and the time-integral of geometric Brownian motion. The second approach, which we call “Dyson series on the common noise” necessitates the calculation of only a one-dimensional integral, but the formula is more complex. This research consisted of both analytical derivations and numerical calculations. The latter show that our formulae are in general more exact, yet more time-consuming to calculate, than the first order expansion of Hagan et al. (2002).

关键词： SABR Model Stochastic Volatility Malliavin Calculus Exponential Formula Option pricing

MICROSTRUCTURE AND COMpRESSIVE pROpERTIES OF REACTION-MILLED NiAl-10wt%TiC COMpOSITE

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Acta Metallurgica Sinica(English Letters) 1998年第4期11卷 281-285页

作者： L.z zHOU and J.T. guo(Dept. of Superalloy and Special Casting, Institute of Metal Research, The Chinese Academy of Sciences,Shenyang 110015, China) Inst of Metal Research The Chinese Acad of Sciences Shenyang China

A NiAl- TiC composite with fine grains was prepared by mechanical alloying elemental powders and hot pressing in vacuum. The TiC particles with diameters of about 50-100nm preferentially distribute on grain boundaries and those with a mean size less than 10nm disperse uniformly throughout the grains. Compressive properties of the composite at room temperature show significantly improved ductility and strength over that of cast NiAl, and its high temperature strength is 3 to 4 times as large as that of cast NiAl.

关键词： intermetallics composite microstructure mechanical property

Non-recurrence of exp(z)/z

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Acta Mathematica Sinica,English Series 2013年第4期29卷 703-716页

作者： guo ping zHAN School of Mathematics and Computational Science Sun Yat-sen University Department of Mathematics Nanjing University

Abstract In this paper, we consider the dynamics of the map z →＊ exp（z）/z on the punctured plane C＊ = C／z. We show that for almost every point z∈C＊, the w-limit set of z is equal to {0, ∞}. In particular, t... 详细信息

关键词： Non-recurrence w-limit set Julia set nesting condition

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驱控一体的旋拧式果实采摘执行器设计与试验

农机化研究 2025年第3期47卷 48-55页

作者：严童杰冯青春郭鑫杨宁江苏大学电气信息工程学院江苏镇江212000 北京市农林科学院智能装备技术研究中心北京100097 国家农业智能装备工程技术研究中心北京100097 农业智能装备技术北京市重点实验室北京100097

针对果园智能化采收作业需要,设计了支持总线扩展的驱控一体旋拧采摘末端执行器,旨在为多臂并行采摘机器人研发提供支撑。在对标准苹果树果实物理形态统计分析基础上,结合人工采摘方法,提出了“吸附-夹持-旋拧”的采摘机械操作方法,并... 详细信息

针对果园智能化采收作业需要,设计了支持总线扩展的驱控一体旋拧采摘末端执行器,旨在为多臂并行采摘机器人研发提供支撑。在对标准苹果树果实物理形态统计分析基础上,结合人工采摘方法,提出了“吸附-夹持-旋拧”的采摘机械操作方法,并设计了基于双舵机驱动的紧凑型采摘执行机构,对其吸盘、夹持和旋拧电机的关键参数进行了优化设计。面向多执行并行采摘需要,设计了基于CANopen通讯的采摘操作驱动器,实现了多执行器的总线扩展。通过现场试验对执行器作业性能进行了测试,结果表明:果实大小在60~100 mm之间,采摘成功率可达到90%,吸盘最优停留时间为1.00 s,吸盘最优接近距离为1.0 mm,最优旋拧角度为360°。

关键词：采摘机器人驱控一体旋拧采摘 CANopen

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Nano Calcium-Deficient Hydroxyapatite/O-carboxymethyl Chitosan-CaCl_(2) Microspheres Loadedwith RheinforBone Defect Repair

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Journal of Bionic Engineering 2022年第4期19卷 1087-1099页

作者： zhenzhen Tian Yuanyuan guo Xiuying Yang Kebing guo Jingou Ji Shilei Hao School of Chemistry and Chemical Engineering Chongqing UniversityNo.55University City South RoadShapingba DistrictChongqing 401331China Key Laboratory of Biorheological Science and Technology Ministry of EducationCollege of BioengineeringChongqing UniversityChongqing 400030China Guizhou KingMed Center for Clinical Laboratory Co. LtdGuizhou 550001China

Glutaraldehyde(GA),the most widely used crosslinking agent for biomaterials,is ***_(2) is of particular interest due to its non-toxic *** can chelate Ca^(2+)and promote bone *** we reported a novel nano calcium-deficient hydroxyapatite/O-carboxymethyl chitosan-CaCl_(2) microspheres loaded with rhein(RH-nCDHA/OCMC-CaCl_(2) microspheres)using CaCl_(2) as crosslinking agent for bone defect *** obtained microspheres were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),thermogravimetric analysis(TG)and Fourier transform infrared spectroscopy(FT-IR).The surface of the obtained microspheres is rough with quite a few *** nano calcium-deficient hydroxyapatite(nCDHA)accounts for about 70% of the total weight of the microspheres,which is equivalent to the proportion of inorganic substances in human bones.A high encapsulation efficiency(EE)and loading capacity(LC)of the microspheres loaded with rhein was 90.20±0.60% and 11.03±0.30%,*** microspheres using CaCl_(2) in simulated body fluid(SBF)after 14 days,the drug released continuously and bone-like apatite formed like *** cells on the surface of the RH-nCDHA/OCMC-CaCl_(2) microspheres grew better comparing with nCDHA/OCMC-GA microspheres and the skull defects of rats after landfill can be almost repaired after 8 weeks,which revealed the potential of the microspheres for bone repair.

关键词： Nano calcium-deficient hydroxyapatite O-carboxymethyl chitosan Rhein Microspheres Bone repair