检索结果-南通市图书馆

refnement of the supercontinent cycle with Hf, Nd and Sr isotopes

Geoscience Frontiers 2013年第6期4卷 667-680页

作者： Kent c.condie richard c.aster Department of Earth and Environmental Science New Mexico Institute of Mining and Technology Geosciences Department Colorado State University

The combined use of Hf,Nd and Sr isotopes is more useful in understanding the supercontinent cycle than the use of only Hf isotopic data from detrital *** and Nd seawater isotopes,although not as precise as εNd and εHf distributions,also record input from ocean ridge *** detrital zircons where sources cannot be precisely located because of crustal recycling,both the location and tectonic setting often can be constrained for whole-rock Nd isotopic ***,primary zircon sources may not reside on the same continent as derivative detrital zircons due to supercontinent breakup and *** to all of the isotopic studies are geographic sampling biases reflecting outcrop distributions,river system sampling,or geologists,and these may be responsible for most of the decorrelation observed between isotopic *** between 3.5 and 2 Ga based on εHf median values of four detrital zircon databases as well as our compiled εNd database are noisy but uniformly distributed in time,whereas data between 2 and 1 Ga data are more tightly clustered with smaller *** age peaks suggest that both isotopic systems are sampling similar types of *** after 1 Ga and before 3.5 Ga do we see wide variations and significant disagreement between databases,which may partially reflect variations in both the number of sample locations and the number of samples per *** and internal orogens show similar patterns in εNd and εHfwith age suggesting that both juvenile and reworked crustal components are produced in both types of orogens with similar ***,both types of orogens clearly produce more juvenile isotopic signatures in retreating mode than in advancing *** secular changes in εHf and εNd distributions correlate with the supercontinent *** supercontinent breakup is correlated with short-lived decreasing εHf and εNd （≤ 100 Myr） for most supercontinents,there is no isotopic evidence for

关键词： Supercontinent cycle Hf isotopes Nd isotopes collisional orogens Accretionary orogens

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Kinematic analysis of flexible bipedal robotic systems

引用

Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 795-818页

作者： r.FAZEL A.M.SHAFEI S.r.NEKOO Department of Mechanical Engineering Shahid Bahonar University of KermanKerman ***Iran Departamento de Ingenieria de Sistemas y Automatica Escuela Técnica Superior de IngenieriaUniversidad de SevillaSeville 41092Spain

In spite of its intrinsic complexities,the passive gait of bipedal robots on a sloping ramp is a subject of interest for numerous *** distinguishes the present research from similar works is the consideration of flexibility in the constituent links of this type of robotic *** is not a far-fetched assumption because in the transient(impact)phase,due to the impulsive forces which are applied to the system,the likelihood of exciting the vibration modes increases ***,the human leg bones that are involved in walking are supported by viscoelastic muscles and ***,for achieving more exact results,it is essential to model the robot links with viscoelastic *** this end,the Gibbs-Appell formulation and Newton's kinematic impact law are used to derive the most general form of the system's dynamic equations in the swing and transient phases of *** most important issue in the passive walking motion of bipedal robots is the determination of the initial robot configuration with which the system could accomplish a periodic and stable gait solely under the effect of gravitational *** extremely unstable nature of the system studied in this paper and the vibrations caused by the impulsive forces induced by the impact of robot feet with the inclined surface are some of the very serious challenges encountered for achieving the above-mentioned *** overcome such challenges,an innovative method that uses a combination of the linearized equations of motion in the swing phase and the algebraic motion equations in the transition phase is presented in this paper to obtain an eigenvalue *** solving this problem,the suitable initial conditions that are necessary for the passive gait of this bipedal robot on a sloping surface are *** effects of the characteristic parameters of elastic links including the modulus of elasticity and the Kelvin-Voigt coefficient on the walking stability of this type of

关键词： bipedal robot flexible link swing phase transient phase eigenvalue problem Kelvin-Voigt coefficient

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Holographic dark energy in non-conserved gravity theory

引用

communications in Theoretical Physics 2024年第4期76卷 126-133页

作者： H r Fazlollahi Institute of Gravitation and cosmology Peoples Friendship University of Russia(RUDN University)6 Miklukho-Maklaya StMoscow117198Russia

recently, reconsidering the rastall idea T_(μ;νν)^(v)=α_(,μ) through relativistic thermodynamics gives a new form for the scalar field α which led us to construct modern modified theory of gravity debugged ‘non-conserved gravity theory’ Fazlollahi 2023 Euro. Phys. J. c 83 923. This theory unlike other modified theories of gravity cannot directly explain the current acceleration expansion in the absence of the cosmological constant and or existence of other forms of dark energy. Hence, in this study we have reinvestigated holographic dark energy Ρ_(X)~H^(2) in the non-conserved theory of gravity. In this context, the density and pressure of dark energy depend on the non-conserved term and density of the dust matter field. As shown, due to non-conservation effects on large-scale structures, unlike the original holographic model, our model onsets an acceleration epoch for the current Universe satisfies observations. Moreover, the interaction and viscous scenarios are studied for this model.

关键词： non-conserved gravity covariant form of thermodynamics holographic dark energy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Light sheet microscope scanning of biointegrated microlasers for localized refractive index sensing

引用

Photonics research 2024年第8期12卷 1673-1680页

作者： rOSS c.cOWIE MArcEL ScHUBErT SUPA School of Physics and AstronomyUniversity of St AndrewsSt AndrewsUK Humboldt centre for Nano and Biophotonics Department of ChemistryUniversity of CologneCologneGermany

Whispering gallery mode(WGM)microlasers are highly sensitive to localized refractive index changes allowing to link their emission spectrum to various chemical,mechanical,or physical *** recently found applications in biological studies within single cells,in three-dimensional samples such as multicellular spheroids,or in ***,detailed studies of biological samples also need to account for the structural heterogeneity of tissues and live animals,therefore requiring a combination of high-resolution microscopy and laser ***,we design and construct a light sheet fluorescence microscope with a coupled spectrometer for use in microlaser studies for combined high-resolution,high-speed imaging and WGM spectral *** light sheet illumination profile and the decoupled geometry of excitation and emission hereby directly affect the lasing and sensing properties,mainly through geometric constraints and by light coupling *** demonstrate the basic working principle of microlaser spectroscopy under light sheet excitation and measure the absolute refractive index within agarose and in zebrafish tail muscle *** further analyze the light coupling conditions that lead to the occurrence of two separate oscillation *** so-called cross modes can be scanned around the entire microlaser surface,which allows to estimate a surface-averaged refractive index profile of the microlaser environment.

关键词： refractive index excitation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Important step towards an understanding of the exotic Z_(c)(3900)

引用

Science china(Physics,Mechanics & Astronomy) 2024年第9期67卷 199-200页

作者： c.Hanhart Institute for Advanced Simulation Forschungszentrum JulichJilich D-52425Germany

The Standard Model of particle physics,which contains the field theories for the electro-weak interaction(QED)and the strong interaction(QcD),is an extremely successful theory describing a huge variety of phenomena at... 详细信息

关键词： interaction atomic describing

来源：

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

Investigating the impact of the universal function of the nuclear proximity potential in heavy-ion fusion cross sections

引用

communications in Theoretical Physics 2024年第5期76卷 86-93页

作者： r Gharaei E Sarvari Department of Physics Sciences FacultyHakim Sabzevari UniversityPO Box 397SabzevarIran Department of Physics Faculty of ScienceFerdowsi University of MashhadPO Box 91775-1436MashhadIran Science Faculty Department of PhysicsTarbiat Modares UniversityTehranIran

The fusion barriers and cross sections of 15 colliding systems with 320≤Z_(1)Z_(2)≤1512 are investigated in detail to understand the influence of the universal function of proximity potential formalism in the heavy-ion fusion *** realize this goal,we select three versions of the phenomenological proximity potentials,including Prox.77,Zhang 2013,and Guo 2013,to calculate the nucleus-nucleus *** experimental fusion cross sections for the selected reactions are analyzed using the standard coupled-channel calculations,including couplings to the low-lying 2^(+)and 3^(-)states in the target and *** calculated results show that the universal functions of the Guo 2013 and Prox.77 models provide the lowest and highest fusion barriers,*** addition,it is found that the height of the fusion barriers is enhanced by increasing the mass number of the projectile from light to heavy *** highest sensitivity to the mass number of the projectile belongs to the results of Prox.77.A discussion is also presented on the influence of the universal function on the radial behavior of the interaction potential in the allowed region for overlapping *** results reveal that the best fit to the experimental data of the fusion cross sections for the reactions involving light and medium nuclei is obtained using the universal function of the Zhang 2013 *** the heavier systems,the results of the Guo 2013 model at sub-barrier energies provide a good description of the available data.

关键词： fusion reactions proximity-type potentials universal function coupled-channel calculations

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Multinuclear Mr and MrI study of lithium-ion cells using a variable field magnet and a fixed frequency rF probe

引用

Magnetic resonance Letters 2024年第1期4卷 10-20页

作者： Andrés ramírez Aguilera Florin Marica Kevin J.Sanders Md Al raihan c.Adam Dyker Gillian r.Goward Bruce *** UNB MrI centre Department of PhysicsUniversity of New BrunswickFrederictonNew BrunswickE3B 5A3Canada Department of chemistry McMaster UniversityHamiltonOntarioL8S 4L8Canada Department of chemistry University of New BrunswickFrederictonNew BrunswickE3B 5A3Canada

An exploratory multinuclear magnetic resonance(Mr)and magnetic resonance imaging(MrI)study was performed on lithium-ion battery cells with ^(7)Li,^(19)F,and ^(1)H measurements.A variable field superconducting magnet with a fixed frequency parallel-plate radiofrequency(rF)probe was employed in the *** magnetic field was changed to set the resonance frequency of each nucleus to the fixed rF probe frequency of 33.7 *** cartridge-like lithium-ion cells,with graphite anodes and LiNi_(0.5)Mn_(0.3)co_(0.2)O_(2)(NMc)cathodes,were *** cell was pristine,and one was charged to a cell voltage of 4.2 *** results presented demonstrate the great potential of the variable field magnet approach in multinuclear measurement of lithium-ion *** methods open the door for developing faster and simpler methods for detecting,quantifying,and interpreting Mr and MrI data from lithium-ion and other batteries.

关键词： Multinuclear Mr/MrI Variable field magnet Lithium-ion battery Parallel-plate rf probe

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A brief history of the compendium of Physical Activities

引用

Journal of Sport and Health Science 2024年第1期13卷 3-5页

作者： Barbara E.Ainsworth Stephen D.Herrmann David r.Jacobs Jr. Melicia c.Whitt-Glover catrine Tudor-Locke School of Exercise and Health Shanghai University of SportShanghai 200438China college of Health Solutions Arizona State UniversityPhoenixAZ 85003USA Kansas center for Metabolism and Obesity research University of Kansas Medical CenterKansas CityKS 66160USA Division of Epidemiology and community Health University of MinnesotaMinneapolisMN 55455USA Gramercy research Group KnightdaleNC 27545USA college of Health and Human Services University of North Carolina at CharlotteCharlotteNC 28223USA

The compendium of Physical Activities(compendium)was developed to address consistent assignment of physical activity(PA)intensity values used in PA epidemiology research of the association between PA and health outcomes.1The known protective effects of PA on incident health outcomes traces to the mid-1900s,with over 50 studies examining coronary heart disease(cHD)as the outcome of interest.

关键词： epidemiology Activities protective

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A toast to a zebrafish germ cell induction cocktail

引用

Science china(Life Sciences) 2024年第6期67卷 1314-1315页

作者： Mary c.Mullins Department of cell and Developmental Biology University of Pennsylvania Perelman School of MedicinePhiladelphia 19104USA

The zebrafish field is ringing in the new year with a publication from Yonghua Sun's laboratory(Wang et al.,2023)of a cocktail of germline factors that can induce all cells of the zebrafish embryo into primordial germ cells(PGcs)at phenomenal *** major advance is not only of great interest to germ cell biologists,but it has important applications to the entire zebrafish field,as shown in Wang et al.(2023).

关键词： fish zebra field

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Pile foundation in alternate layered liquefiable and non-liquefiable soil deposits subjected to earthquake loading

引用

Earthquake Engineering and Engineering Vibration 2024年第2期23卷 359-376页

作者： Praveen Huded M Suresh r Dash LEA Associates South East Asia Pvt.Ltd. New Delhi 110044India Indian Institute of Technology Bhubaneswar Khurda 752050India

Pile foundations are still the preferred foundation system for high-rise structures in earthquake-prone *** foundations have experienced failures in past earthquakes due to *** on pile foundations in liquefiable soils has primarily focused on the pile foundation behavior in two or three-layered soil ***,in natural occurrence,it may occur in alternative layers of liquefiable and non-liquefiable ***,the experimental and/or numerical studies on the layered effect on pile foundations have not been widely addressed in the *** of the design codes across the world do not explicitly mention the effect of sandwiched non-liquefiable soil layers on the pile *** the present study,the behavior of an end-bearing pile in layered liquefiable and non-liquefiable soil deposit is studied *** study found that the kinematic bending moment is higher and governs the design when the effect of the sandwiched non-liquefied layer is considered in the analysis as opposed to when its effect is ***,ignoring the effect of the sandwiched non-liquefied layer in a liquefiable soil deposit might be a nonconservative design approach.

关键词： pile foundation liquefaction alternately layered soil fixity effect layered effect

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：