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黄土隧道围岩局部浸水静力特征分析

科学技术与工程 2024年第1期24卷 371-377页

作者：王少雄曹小平王建华兰州交通大学土木工程学院兰州730070

中国西北地区湿陷性黄土分布广泛,由于其具有孔隙大、强度低等性质,导致黄土隧道修建时面临极大的困难与挑战。为了深入研究黄土隧道围岩局部浸水后对隧道结构稳定性的影响,依托定西锦屏隧道,借助Midas/GTS建立隧道模型,分别针对正常开... 详细信息

中国西北地区湿陷性黄土分布广泛,由于其具有孔隙大、强度低等性质,导致黄土隧道修建时面临极大的困难与挑战。为了深入研究黄土隧道围岩局部浸水后对隧道结构稳定性的影响,依托定西锦屏隧道,借助Midas/GTS建立隧道模型,分别针对正常开挖和局部浸水两种工况进行对比分析。研究局部浸水后黄土隧道围岩和衬砌结构的变形规律和力学特征。结果显示:正常开挖与浸水后,围岩最大沉降值均出现在隧道拱顶,开挖后最大沉降值为9.60 mm,局部浸水后围岩最大沉降量增大到13.18 mm;正常开挖后围岩最大主应力为59 kPa,浸水后,围岩最大主应力出现在拱顶与仰拱处,最大值为89 kPa。黄土隧道围岩局部浸水后,衬砌结构的最大压应力为5.06 MPa,最大拉应力为2.08 MPa。最大压应力为设计强度的42%,最大拉应力超过抗拉设计强度。

关键词：黄土隧道局部浸水数值模拟力学特征

Long-term evolution and gravitational wave radiation of neutron stars with differential rotation induced by r-modes

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Research in Astronomy and Astrophysics 2009年第9期9卷 1024-1034页

作者： Yun-Wei Yu xiao-Feng cao xiao-ping Zheng Institute of Astrophysics Huazhong Normal University Wuhan 430079 China

In a second-order r-mode theory, Sa and Tome found that the r-mode oscillation in neutron stars （NSs） could induce stellar differential rotation, which naturally leads to a saturated state of the oscillation. Based on a consideration of the coupling of the r-modes and the stellar spin and thermal evolution, we carefully investigate the influences of the differential rotation on the long-term evolution of isolated NSs and NSs in low-mass X-ray binaries, where the viscous damping of the r-modes and its resultant effects are taken into account. The numerical results show that, for both kinds of NSs, the differential rotation can significantly prolong the duration of the r-modes. As a result, the stars can keep nearly a constant temperature and constant angular velocity for over a thousand years. Moreover, the persistent radiation of a quasi-monochromatic gravitational wave would also be predicted due to the long-term steady r-mode oscillation and stellar rotation. This increases the detectability of gravitational waves from both young isolated and old accreting NSs.

关键词： stars: neutron -- stars: evolution -- stars: rotation -- gravitational waves

First Total Synthesis of Hyacinthacine A_6 from the Protected Derivative of Polyhydroxylated Pyrrolidine

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Chemical Research in Chinese Universities 2008年第4期24卷 469-472页

作者： ZHANG Tao-xiang ZHOU Ling cao xiao-ping State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000 P. R. China

（1S、2R、3R、5R、7aR）-1,2-Dihydroxy-3-hydroxy methyl-5-methylpyrrolizidine（hyacinthacine A6, I） was synthesized by Wittig＇s methodology via the reaction of aldehyde 6, prepared from the partially protected derivative of polyhydroxylated pyrrolidine, with appropriated ylides, followed by cyclization through the intemal reductive amination process of the resulting a,B-unsaturated ketone 7, and total deprotection.

关键词： Hyacinthacine A6 Pyrrolidines Wittig reaction Cyclization

Regulated polarization degree of upconversion luminescence and multiple anti-counterfeit applications

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Rare Metals 2024年第5期43卷 2172-2183页

作者： Dong-ping Wen ping Chen Yi Liang xiao-Ming Mo cao-Feng Pan Center On Nanoenergy Research Guangxi Key Laboratory for Relativistic AstrophysicsSchool of Physical Science and TechnologyGuangxi UniversityNanning 530004China Key Laboratory of Micronano Energy and Sensor CAS Center for Excellence in NanoscienceBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 100140China

Polarization upconversion luminescence(PUCL)of lanthanide ions(Ln^(3+))has been widely used in single particle tracking,microfluidics detection,three-dimensional displays,and so ***,no effective strategy has been developed for modulating *** we report a strategy to regulate PUCL in Ho^(3+)-doped NaYF4single nanorods based on the number of upconversion *** constructing a multiphoton upconversion system for Ho^(3+),we regulate the degree of polarization(DOP)of PUCL from 0.590 for two-photon luminescence to 0.929 for three-photon upconversion luminescence(UCL).Furthermore,our strategy is verified from cross-relaxation between Ho^(3+)and Yb^(3+),excitation wavelength,excitation power density,and local site *** this regulation strategy of PUCL has also been achieved in Tm^(3+),with the DOP ranging from 0.233 for two-photon luminescence to 0.925 for four-photon UCL Besides,multi-dimensional anti-counterfeiting display has been explored with *** work provides an effective strategy for regulating PUCL and also provides more opportunities for the development of polarization display optical encoding,anti-counterfeiting,and integrated optical devices.

关键词： Polarization upconversion luminescence Degree of polarization Population density of excited state Number of upconversion photons Polarization anti-counterfeitingdisplay

Prediction of chemical short-range order in high-/medium-entropy alloys

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Journal of Materials Science & Technology 2024年第2期169卷 115-123页

作者： Pei-Yu cao Jing Wang ping Jiang Yun-Jiang Wang Fu-ping Yuan xiao-Lei Wu State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of ScienceBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Chemical short-range orders(CSROs),as the built-in sub-nanoscale entities in a high-/medium-entropy alloy(H/MEA),have aroused an ever-increasing *** multi-principal elements in an H/MEA to form a complex concentrated solution,a variety of sub-systems of species exist to induce the metastable ordered compounds as candidates for ultimate *** issues remain pending on the origin of CSROs as to how to judge if CSRO will form in an H/MEA and particularly,what kind of CSROs would be stably produced if there were multiple ***,the first-principles method,along with the proposed local formation energy calculation in allusion to the atomic-scale chemical heterogeneities,is used to predict the CSRO formation based on the mechanical stability,thermodynamic formation energy,and electronic *** simulations are detailed in an equiatomic ternary VCoNi MEA with three kinds of potential compounds,i.e.,L1_(1),L1_(2),and B2,in the face-centered cubic *** turns out that L1_(1)is stable but hard to grow up so as to become the final CSRO.L1_(1)is further predicted as CSROs in CrCoNi,but unable to form in FeCoNi and CrMnFeCoNi *** predictions are consistent with the experimental *** findings shed light on understanding the formation of *** method is applicable to other H/MEAs to design and tailor CSROs by tuning chemical species/contents and thermal processing for high performance.

关键词： Short-range order High-entropy alloy Microstructure First-principles calculation Gibbs free energy Local electronic density of states

An Improved Modulation Strategy for Single-phase Three-level Neutral-point-clamped Converter in Critical Conduction Mode

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 981-990页

作者： Ning Li Yujie cao xiaokang Liu Yan Zhang Ruotong Wang Lin Jiang xiao-ping Zhang School of Electrical Engineering Xi’an University of TechnologyXi’anChina the Department of Electronics Information and BioengineeringPolitecnico di MilanoMilanItaly Xi’an Jiaotong University Xi’anChina the Department of Electrical Engineering and Electronics University of LiverpoolLiverpoolU.K. the Department of Electronic Electrical and Systems EngineeringUniversity of BirminghamBirminghamU.K.

Two-level totem-pole power factor correction(PFC)converters in critical conduction mode(CRM)suffer from the wide regulation range of switching ***,in highfrequency applications,the number of switching times increases,resulting in significant switching *** solve these issues,this paper proposes an improved modulation strategy for the single-phase three-level neutral-point-clamped(NPC)converter in CRM with *** optimizing the discharging strategy and switching state sequence,the switching frequency and its variation range have been efficiently *** detailed performance analysis is also presented regarding the switching frequency,the average switching times,and the effect of voltage gain.A 2 k W prototype is built to verify the effectiveness of the proposed modulation strategy and analysis *** with the totem-pole PFC converter,the switching frequency regulation range of the three-level PFC converter is reduced by 36.48%and the average switching times is reduced by 45.10%.The experimental result also shows a 1.2%higher efficiency for the three-level PFC converter in the full load range.

关键词： Critical conduction mode(CRM) on-board charger switching frequency range switching times power factor correction(PFC) three-level converter

An evaluation equation of TG experiment data based on iso-conversion method for activation energy

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Journal of Chemistry and Chemical Engineering 2008年第4期2卷 75-78页

作者： FAN Du-ping cao xiao-ping Changsha Blower Company Limited Changsha 410014 China Hunan Radio and Television University Changsha 410014 China

The iso-conversion method to could calculate the kinetics parameters effectively, the present paper built an evaluation equation for iso-conversion methods according to the thermo kinetics integral equation and analyses the temperatures of the same degree of conversion for different heating rates by ideal TG （thermo-gravity） curve data. It is obtained that the temperatures of the same degree of conversion for different heating rates＇ TG curve have good linearity connection validating the correction of the evaluation equation for iso-conversion methods and the scope of linear slope for theratio between heating rates being 2 is 1.05 to 1.09.

关键词： iso-conversion methods kinetics parameters evaluation equation ideal TG curve

Event-triggered impulsive synchronization of heterogeneous neural networks

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Science China(Information Sciences) 2024年第2期67卷 331-332页

作者： Zhengxin WANG Chongfang JIN Wangli HE Min xiao Guo-ping JIANG Jinde cao College of Science Nanjing University of Posts and Telecommunications Jiangsu Engineering Lab for IOT Intelligent Robots (IOTRobot) Nanjing University of Posts and Telecommunications Key Laboratory of Smart Manufacturing in Energy Chemical Process Ministry of EducationEast China University of Science and Technology School of Automation Nanjing University of Posts and Telecommunications School of Mathematics Southeast University Yonsei Frontier Lab Yonsei University

Synchronization is one of the most important dynamics in neural networks. Several scholars have studied the quasi-synchronization of heterogeneous neural networks [1],wherein external controllers play a significant role. Impulsive control, a kind of energy-saving control, is activated instantaneously only at specific discrete moments.

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浸润接触线的摩擦性质与固体表面张力的Wenzel行为

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物理学报 2005年第5期54卷 2202-2206页

作者：曹晓平蒋亦民中南大学物理科学与技术学院长沙410083

依据Adam和Jessop关于固液气三相接触线具有静摩擦性的观点 ,能从浸润接触角数据推算出固体的表面张力系数 ,但结果显然会与摩擦条件的具体形式有关 .以报道的不锈钢和聚丙烯实验数据为例 ,通过对比Mises和Amonton两种摩擦定律给出的... 详细信息

依据Adam和Jessop关于固液气三相接触线具有静摩擦性的观点 ,能从浸润接触角数据推算出固体的表面张力系数 ,但结果显然会与摩擦条件的具体形式有关 .以报道的不锈钢和聚丙烯实验数据为例 ,通过对比Mises和Amonton两种摩擦定律给出的表面张力系数 ,后者给出的张力才具有总是随表面粗糙性的增大而增加的Wenzel效应 ,以及当固液 ,固气界面的张力系数之差等于液气界面的张力系数时 ,退后角将变为零的全浸润条件 .这似乎表明用Amonton定律描写接触线的静摩擦要更为合理 .

关键词：浸润角静摩擦固体表面张力 Amonton定律接触角滞后