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Probing top-quark operators with precision electroweak measurements

Chinese Physics C 2022年第11期46卷 118-142页

作者： Yiming Liu Yuhao Wang Cen zhang lei zhang Jiayin Gu Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China School of Physics Nanjing UniversityNanjing 210093China Department of Physics and Center for Field Theory and Particle Physics Fudan UniversityShanghai 200438China Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Fudan UniversityShanghai 200433China School of Physical Sciences University of Chinese Academy of ScienceBeijing 100049China Center for High Energy Physics Peking UniversityBeijing 100871China

In the standard model effective field theory,operators involving the top quark are generally difficult to probe and can generate sizable loop contributions to electroweak precision observables measured by past and future lepton *** the high precision of electroweak measurements compensate for loop suppression and provide competitive reaches on these operators?Would the inclusion of these contributions introduce too many additional parameters for a meaningful global electroweak analysis to be performed?In this paper,we perform a detailed phenomenological study to address these two important *** on eight dimension-6 operators that generate anomalous couplings between electroweak gauge bosons and third-generation quarks,we calculate their one loop contributions to e^(+)e^(-)→ff processes,both on and off the Z-pole,and the e^(+)e^(-)→WW process.A global analysis is performed with these eight operators and those that contribute to the above processes at tree level using measurements at the LEP,SLC,and several low energy *** find that although current electroweak precision measurements are sensitive to the one-loop effects of top-quark operators,it is difficult to separate them from the operators that contribute at tree level,making a global analysis rather *** further assumptions(for instance,new physics contributes to only third generation quark operators and the S and T parameters),competitive reaches may be obtained in a global *** important finding of our study is that the two operators that generate the dipole interactions of the bottom quark have a significant impact on the Z-pole measurements and should not be *** also discuss the implications of the recently reported W-boson mass measurement at the CDF for our ***,we estimate the reaches of future lepton colliders in probing top-quark operators with precision electroweak measurements.

关键词： loop-induced processes effective field theory Monte Carlo generator top quark

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Mechanical effects of circular liquid inclusions inside soft matrix:role of internal pressure change and surface tension

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Applied Mathematics and Mechanics(English Edition) 2021年第4期42卷 501-510页

作者： lei zhang College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing 400044China

The mechanical effects of dilute liquid inclusions on the solid-liquid composite are explored,based on an analytical circular inclusion model incorporating the internal pressure change of the liquid and the surface tension of the *** simple explicit dependences of the stress field and effective stiffness on the bulk modulus and the size of the liquid,the surface tension,and Poisson’s ratio of the matrix are *** results show that the stresses in the matrix are reduced,and the stiffness of the solid-liquid composite is enhanced with the consideration of either the surface tension or the internal pressure ***,the effective Young’s modulus predicted by the present model for either soft or stiff matrices agrees well with the known experimental *** addition,according to the theoretical results,it is possible to stiffen a soft solid by pressured gas with the presence of the surface tension of the solid-gas interface.

关键词： liquid inclusion stress field effective stiffness surface tension internal pressure change

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金属二聚体和氮共掺杂石墨烯(Gra)M_(2)N_(6)-Gra(M=Cr-Cu)的NO_(2)吸附特性理论研究

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原子与分子物理学报 2025年第5期42卷 35-42页

作者：张展博余娇魏亚茹张轩靳鑫张子音杨保成张雷雷黄河科技学院纳米功能材料研究所郑州450063

NO_(2)是空气污染物的主要成分之一,设计和开发高效的气敏传感器对NO_(2)进行检测具有重要意义.本工作利用基于密度泛函理论(DFT)的第一性原理计算方法对不同过渡金属原子形成的金属二聚体和氮共掺杂石墨烯(Gra)M_(2)N_(6)-Gra(M=Cr-Cu)... 详细信息

NO_(2)是空气污染物的主要成分之一,设计和开发高效的气敏传感器对NO_(2)进行检测具有重要意义.本工作利用基于密度泛函理论(DFT)的第一性原理计算方法对不同过渡金属原子形成的金属二聚体和氮共掺杂石墨烯(Gra)M_(2)N_(6)-Gra(M=Cr-Cu)的NO_(2)吸附特性进行了研究.结果表明,NO_(2)分子与M_(2)N_(6)-Gra之间均存在明显的化学吸附作用.其中,Ni_(2)N_(6)-Gra和Cu_(2)N_(6)-Gra体系具备较为适中的恢复时间(分别约为5秒和14分钟),这意味着这两个体系是开发新型NO_(2)气敏材料的潜在候选者.其它体系(M_(2)N_(6)-Gra,M=Cr-Co)强的吸附作用导致恢复时间过长,从而使得它们不适合作为NO_(2)气敏材料.这一研究不仅有望为设计和开发性能优异的新型NO_(2)气敏材料提供有益理论指导,还将有益于人们深入认识M_(2)N_(6)-Gra材料的NO_(2)电催化合成NO或NH 3性能.

关键词： M_(2)N_(6)-Gra NO_(2)吸附密度泛函理论

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可干预因素与关节运动损伤的因果关系

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中国组织工程研究 2025年第9期29卷 1953-1962页

作者：董婷婷陈天鑫李妍张晟张磊中国中医科学院望京医院骨关节四科北京市100102

背景:生活方式、代谢特征及营养摄入等干预因素与关节运动损伤的因果关系逐渐得到临床研究的重视,然而可干预因素与关节运动损伤的因果关系尚不明确。目的:运用孟德尔随机化的方法,探讨可干预因素与关节运动损伤的因果关系,为运动损伤... 详细信息

背景:生活方式、代谢特征及营养摄入等干预因素与关节运动损伤的因果关系逐渐得到临床研究的重视,然而可干预因素与关节运动损伤的因果关系尚不明确。目的:运用孟德尔随机化的方法,探讨可干预因素与关节运动损伤的因果关系,为运动损伤预防提供依据。方法:从公开数据库获取可干预因素和关节运动损伤的GWAS数据集,运用逆方差加权法、MR-Egger法、加权中位数法探讨生活方式、代谢特征、营养摄入与关节运动损伤的因果关系。敏感性分析方面,采用Cochran’s Q检验、MR-Egger回归、留一法和MR-PRESSO,以验证结果的稳定性和可靠性。结果与结论:①生活方式方面,咖啡(OR=0.29,95%CI:0.10-0.79,P=0.016)、茶消耗量(OR=0.41,95%CI=0.19-0.85,P=0.017)与足踝关节运动损伤风险下降,咖啡消耗量(OR=3.31,95%CI=1.02-10.73,P=0.046)与肩关节运动损伤风险上升具有潜在因果关系;从未吸烟(OR=0.78,95%CI=0.70-0.87,P=1.49×10^(-5))与足踝关节运动损伤风险下降具有显著因果关系。②代谢特征方面,钙水平(OR=0.88,95%CI=0.79-0.98,P=0.017)与手腕关节运动损伤风险下降具有潜在因果关系。③营养摄入方面,维生素A摄入(OR=1.08,95%CI:1.02-1.13,P=0.007)与膝关节运动损伤风险增加具有潜在因果关系。④敏感性分析方面,Cochran’s Q检验显示存在异质性(P0.05),留一法显示逐个剔除单核苷酸多态性后,结果具有稳定性。⑤此研究初步揭示生活方式、代谢特征及营养摄入等可干预因素对关节运动损伤风险的影响,为关节运动损伤的预防提供研究证据与研究方向。

关键词：孟德尔随机化关节运动损伤可干预因素生活方式代谢特征营养摄入因果关系敏感性分析

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Convolutional adaptive denoising autoencoders for hierarchical feature extraction

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Frontiers of Computer Science 2018年第6期12卷 1140-1148页

作者： Qianjun zhang lei zhang Machine Intelligence Laboratory College of Computer ScienceSichuan UniversityChengdu 610065China

Convolutional neural networks (CNNs) are typical structures for deep learning and are widely used in image recognition and classification. However, the random initialization strategy tends to become stuck at local plateaus or even diverge, which results in rather unstable and ineffective solutions in real applications. To address this limitation, we propose a hybrid deep learning CNN-AdapDAE model, which applies the features learned by the AdapDAE algorithm to initialize CNN filters and then train the improved CNN for classification tasks. In this model, AdapDAE is proposed as a CNN pre-training procedure, which adaptively obtains the noise level based on the principle of annealing, by starting with a high level of noise and lowering it as the training progresses. Thus, the features learned by AdapDAE include a combination of features at different levels of granularity. Extensive experimental results on STL-10, CIFAR-10, andMNIST datasets demonstrate that the proposed algorithm performs favorably compared to CNN (random filters), CNNAE (pre-training filters by autoencoder), and a few other unsupervised feature learning methods.

关键词： convolutional neural networks annealing denoising autoencoder adaptive noise level pre-training

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Seismic fragility analysis of clay-pile-pier systems considering the optimization of ground motion intensity measures

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Earthquake Engineering and Engineering Vibration 2023年第4期22卷 965-977页

作者： zhang Panpan zhang lei zhang Zhen School of Civil Engineering and Architecture Wuhan University of TechnologyWuhan 430070China

The performance of clay-pile-pier system under earthquake shaking was comprehensively examined via three-dimensional finite element analyses,in which the complex stress-strain relationships of a clay and piled pier system were depicted by a hyperbolic-hysteretic and an equivalent elastoplastic model,*** hundred twenty ground motions with varying peak accelerations were considered,along with the variations in bridge superstructure mass and pile flexural *** comparison studies suggested that peak pile-cap acceleration and peak pile-cap velocity are the optimal ground motion intensity measures for seismic responses of the pier and the pile,***,based on two optimal ground motion intensity measures and using curvature ductility to quantify different damage states,seismic fragility analyses were *** pier generally had no evident damage except when the bridge girder mass was equal to 960 t,which seemed to be comparatively insensitive to the varying pile flexural *** comparison,the pile was found to be more vulnerable to seismic damage and its failure probabilities tended to clearly reduce with the increment of pile flexural rigidity,while the influence of the bridge girder mass was relatively minor.

关键词： clay-pile-pier system seismic fragility analysis ground motion intensity measures damage probability

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Engineering yolk-shell CuCo_(2)S_(4)@Cu_(2)O Z-scheme nanoreactors for accelerating generation of value-added chemicals and of degradation multi-organic contaminants

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Journal of Materials Science & Technology 2023年第25期156卷 54-63页

作者： Xue Feng lei zhang College of Chemistry Liaoning University66 Chongshan Middle RoadShenyang 110036China

The synthesis of solar-driven chemical value-added products and the degradation of pollutants is a promising approach for sustainable development. However, achieving these works via photocatalysts with efficient charge-separation, photo-absorption is challenging. A yolk-shell CuCo_(2)S_(4)@Cu_(2)O Z-scheme nanoreactor (YS-CuCo_(2)S_(4)@Cu_(2) O-NR) with octahedron Cu_(2)O as the core and tubular CuCo2 S4 as the shell, has been synthesized by regulating composition and morphology. YS-CuCo_(2)S_(4)@Cu_(2)O-NR shows superior photocatalytic activities for producing H_(2) O_(2) collaborates by selective oxidation of benzyl alcohol (BA) to high value-added benzaldehyde (BAD)/utilized Fenton-like reaction to degrade multi-pollutants through space-confinement effect, reaching 80% conversion and 99% selectivity of BA, a yield of 12 mM g^(−1) for H_(2)O_(2) and above 90% degradation efficiency for multi-pollutants. A photocatalysis nanoconfinement reactor system is proposed and demonstrated by using yolk-shell to enhance the performance of the chemical reaction. Mechanism studies show that the yolk-shell provides confined space to accelerate redox reaction kinetics;while the inner void promotes light harvesting and keeps yolk Cu_(2) O from deactivation;combined with the Z-scheme charge transfer, engineering Cu^(+) /Cu^(2+) active composition, they are favorable for enhancing the H_(2) O_(2) generation and Fenton-like activity. These findings provide new opportunities for application of yolk-shell Z-scheme metal-oxide-based photocatalysts.

关键词： Octahedron yolk-shell structure catalyzer Z-scheme charge transfer H2O_(2)generation Selective oxidation of BA Fenton-like reaction

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Whittaker-Shintani functions for general linear groups over p-adic fields

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Science China Mathematics 2018年第1期61卷 95-110页

作者： lei zhang Department of Mathematics National University of Singapore

In this paper, we recreate the Whittaker-Shintani functions for general linear groups over nonarchimedean fields given by Kato et al. Those generalized spherical functions naturally arise from global zeta integrals of automorphic L-functions. More explicitly, this formula plays a fundamental role in the local calculation over the split places of tensor product L-functions defined by Jiang and zhang(2014) and the twisted automorphic descents introduced by Jiang and zhang(2015).

关键词： Bessel models local factors Whittaker-Shintani functions

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MINIMIZATION PROBLEM FOR SYMMETRIC ORTHOGONAL ANTI-SYMMETRIC MATRICES

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Journal of Computational Mathematics 2007年第2期25卷 211-220页

作者： Yuan lei Anping Liao lei zhang College of Mathematics and Econometrics Hunan University Changsha 410082 China Department of Information and Computing Science Changsha University Changsha 410003 China

By applying the generalized singular value decomposition and the canonical correlation decomposition simultaneously, we derive an analytical expression of the optimal approximate solution ^-X, which is both a least-squares symmetric orthogonal anti-symmetric solu- tion of the matrix equation A^TXA = B and a best approximation to a given matrix X^＊. Moreover, a numerical algorithm for finding this optimal approximate solution is described in detail, and a numerical example is presented to show the validity of our algorithm.

关键词： Symmetric orthogonal anti-symmetric matrix Generalized singular value decomposition Canonical correlation decomposition

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Ethylene-bridged Indenyl-fluorenyl Metallocene Complexes for Efficient Preparation of Allyl-terminated Propylene Oligomers and Polymers via Selective β-Methyl Transfer

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Chinese Journal of Polymer Science 2019年第6期37卷 578-590页

作者： lei zhang Bin zhang Haiyan Ma Shanghai Key Laboratory of Functional Materials Chemistry and Laboratory of Organometallic Chemistry School of Chemistry and Molecular EngineeringEast China University of Science and Technology

Four C_1-symmetric ansa-metallocene complexes, C_2H_4(Ind)(2,7-~tBu_2-Flu)ZrCl_2(4), C_2H_4(3-Bn-Ind)(2,7-~tBu_2-Flu)ZrCl_2(5),C_2H_4(3-Bn-Ind)(3,6-~tBu_2-Flu)ZrCl_2(6), and C_2H_4(3-Bn-Ind)(2,7-~tBu_2-Flu)HfCl_2(7), were synthesized and characterized. The structures of complexes 4, 5, and 7 were further determined via X-ray diffraction studies. Upon activation with modified methylaluminoxane(MMAO) or Al^iBu_3/[Ph_3C][B(C_6F_5)_4](TIBA/TrB), most of these complexes showed high efficiency in catalyzing propylene oligomerization/polymerization to afford products dominantly with allyl terminals via selective β-methyl transfer(β-Me transfer). The introduction of 3-benzyl group on the indenyl ring of the complexes was found to be crucial in enabling highly selective β-Me transfer during the polymerization process, leading to selectivities up to 89% obtained by zirconocene complexes 5 and 6, and up to 91% obtained by hafnocene complex 7. Detailed chain-end analysis by ~1H-NMR, ^(13)C-NMR, and MALDI-TOF mass spectroscopy revealed that the allyl chain-ends of the polymeric products resulted from a selective β-Me transfer process after two successively primary insertions of the monomer. Further studies concerning the dependence of chain release selectivity as well as the molecular weight of products on monomer concentration suggested that both β-Me transfer(major) and β-hydrogen transfer(β-H transfer)(minor) mediated by 5/MMAO and 6/MMAO systems may mainly operate in a bimolecular pathway.

关键词： Metallocene Ethylene-bridged indenyl-fluorenyl ligand Propylene Oligo-/polymerization β-Methyl transfer

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