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A Characterization of T_(2g+1,2) among Alternating Knots

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Acta Mathematica Sinica,English Series 2021年第12期37卷 1841-1846页

作者： Yi ni Department of Mathematics CaltechMC 253-371200 E California BlvdPasadenaCA 91125USA

let K be a genus g alternating knot with Alexander polynomial Δ_(K)(T)=Σ_(i=-g)^(g)a_(i)T^(i).We show that if |a_(g)|=|a_(g-1)|,then K is the torus knot T_(2g+1,±2).This is a special case of the Fox Trapezoidal ***... 详细信息

关键词： Alternating knots Alexander polynomial strongly quasipositive fibered knots

Signature of helium rain and dilute cores in Jupiter’s interior from empirical equations of state

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Earth and Planetary Physics 2020年第2期4卷 111-119页

作者： DongDong ni State Key laboratory of lunar and Planetary Sciences Macao University of Science and Technology Institute for Planets and Exoplanets University of California

Measurements of Jupiter’s gravity field by Juno have been acquired with unprecedented precision, but uncertainties in the planet’s hydrogen–helium equation of state(EOS) and the hydrogen–helium phase separation have meant that differences remain in the interior model predictions. We deduce an empirical EOS from Juno gravity field observations in terms of the hydrostatic equation and then investigate the structure and composition of Jupiter by comparison of the empirical EOS with Jupiter’s adiabats obtained from the physical EOS. The deduced helium mass fraction suggests depletion of helium in the outermost atmosphere and helium concentration in the inner molecular hydrogen region, which is a signature of helium rain in Jupiter’s interior. The deduced envelope metallicity(the heavy-element mass fraction) is as high in the innermost envelope as 11–13 times the solar value. Such a high metallicity provides sharp support to the dilute core model with the heavy elements dissolved in hydrogen and expanded outward. No matter how the core mass is varied, the empirical EOS derived from the two-layer interior model generally suggests higher densities in the innermost envelope than does the best-fit Jupiter’s adiabat;this result is, again, a signature of dilute cores in Jupiter’s interior. Moreover, no matter the core mass,the empirical EOS is found to exhibit an inflexion point in the deep interior, around 10 Mbar, which can be explained as the combined effect of helium concentration in the upper part and dilute cores in the lower part.

关键词： Jupiter,interior abundances,interiors geophysics

Motion of the moonlet in the binary system 243 Ida

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Acta Mechanica Sinica 2018年第1期34卷 214-224页

作者： l.lan Y.ni Y.Jiang J.li School of Aerospace Engineering Tsinghua University State Key laboratory of Astronautic Dynamic Xi'an Satellite Control Center

The motion of the moonlet Dactyl in the binary system 243 Ida is investigated in this paper. First, periodic orbits in the vicinity of the primary are calculated, including the orbits around the equilibrium points and large-scale orbits. The Floquet multipliers’ topological cases of periodic orbits are calculated to study the orbits’ stabilities. During the continuation of the retrograde near-circular orbits near the equatorial plane, two period-doubling bifurcations and one Neimark–Sacker bifurcation occur one by one, leading to two stable regions and two unstable regions. Bifurcations occur at the boundaries of these regions. Periodic orbits in the stable regions are all stable, but in the unstable regions are all unstable. Moreover, many quasi-periodic orbits exist near the equatorial plane. long-term integration indicates that a particle in a quasi-periodic orbit runs in a space like a tire. Quasi-periodic orbits in different regions have different styles of motion indicated by the Poincare sections. There is the possibility that moonlet Dactyl is in a quasi-periodic orbit near the stable region I, which is enlightening for the stability of the binary system.

关键词： Binary system Bifurcation Periodic orbits Quasi-periodic orbits

Hard life in cold waters:Size distribution and gonads show that Greenland halibut temporarily inhabit the Siberian Arctic

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Water Biology and Security 2022年第2期1卷 96-104页

作者： A.N.Benzik l.K.Budanova A.M.orlov Polar Branch of the Russian Federal Research Institute of Fisheries and Oceanography(PINRO Named after N.M.Knipovich) MurmanskRussia Shirshov Institute of Oceanology of the Russian Academy of Sciences(IO RAS) MoscowRussia Russian Federal Research Institute of Fisheries and Oceanography(VniRO) MoscowRussia A.N.Severtsov Institute of Ecology and Evolution RAS(IPEE RAS) MoscowRussia Tomsk State University(TSU) TomskRussia Dagestan State University(DSU) MakhachkalaRussia Caspian Institute of Biological Resources Dagestan Federal Research Center of the Russian Academy of Sciences(CIBR DFRC RAS)MakhachkalaRussia

The range of the Greenland halibut Reinhardtius hippoglossoides(Walbaum,1792)includes vast areas in the northern parts of the Atlantic and Pacific oceans,as well as the seas of the Arctic *** its commercial importance and decades of study,many aspects of its life cycle and reproduction remain poorly ***,we evaluate the size distribution of Greenland halibut in the catches of research surveys in the Barents,Kara,and laptev seas and conduct micro-and macroscopic studies of their gonads in the laptev *** size of Greenland halibut individuals increases from west to east,which is associated with the settling of pelagic juveniles and the subsequent residency of growing individuals near their settling *** the greatest extent,this size imbalance is manifested in the areas most remote from spawning grounds,*** Kara and laptev *** process of maturation in large individuals of Greenland halibut in the Arctic seas is characterized by a state of inhibitionwaiting in the early stages of gametogenesis(previtellogenesis).The data obtained indicate that Greenland halibut in the North Atlantic and the Siberian Arctic have a continuous *** continental slope of the Barents Sea is a spawning and maturing ground,while the northern parts of the Barents and Kara seas,as well as the continental slope of the laptev Sea,are feeding grounds for *** results of this study might serve as a necessary basis for monitoring condition of halibut stocks as well as for reallocation of the total allowable catch between countries that exploited them in the Norwegian and Barents seas.

关键词： Reinhardtius hippoglossoides lifecycle Reproduction Testes Ovaries Spawning ground Maturation Barents Sea Kara Sea laptev Sea

Toward a Phylogeny of the Kukri Snakes,Genus Oligodon

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Asian Herpetological Research 2010年第1期1卷 1-21页

作者： Marc D.Green ni.olai.l.orlov Robert W.Murphy Department of Natural History Royal Ontario Museum100 Queen’s Park TorontoON M5S 2C6 Canada Zoological Institute Russian Academy of SciencesUniversitetskaya nab 1 St.Petersburg 199034Russia State Key laboratory of Genetic Resources and Evolution Kunming Institute of ZoologyChinese Academy of Sciences

The South and Southeast Asian snake genus Oligodon, known for its egg-eating feeding behavior, has been a taxonomically and systematically challenging group. This work provides the first phylogenetic hypothesis for the genus. We use approximately 1900 base pairs of mitochondrial DNA sequence data to infer the relationships of these snakes, and we examine congruence between the phylogeny and hemipenial characters. A hypothesis for the position of Oligodon within the Colubridae is also proposed. We discuss the implications of the phylogeny for previous taxonomic groupings, and consider the usefulness of the trees in analysis of behavior and biogeography of this genus.

关键词： Oligodon genealogy Colubridae hemipenis mitochondrial DNA Southeast Asia South Asia

Developing new understanding of photoelectrochemical water splitting via in-situ techniques:A review on recent progress

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Green Energy & Environment 2017年第2期2卷 100-111页

作者： Jiajie Cen Qiyuan Wu Mingzhao liu Alexander orlov Department of Materials and Science Engineering Stony Brook University Center for Functional Nanomaterials Brookhaven National Laboratory

Photoelectrochemical(PEC) water splitting is a promising technology for solar hydrogen production to build a sustainable, renewable and clean energy economy. Given the complexity of the PEC water splitting processes, it is important to note that developing in-situ techniques for studying PEC water splitting presents a formidable challenge. This review is aimed at highlighting advantages and disadvantages of each technique, while offering a pathway of potentially combining several techniques to address different aspects of interfacial processes in PEC water splitting. We reviewed recent progress in various techniques and approaches utilized to study PEC water splitting, focusing on spectroscopic and scanning-probe methods.

关键词： In-situ Water splitting IMPS TAS SPM

Experimental isothermal section phase diagram of Ho-Fe-In at 773 K and magnetic properties of Ho_(12)Fe_(2.08)In_(2.92) alloy

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Rare Metals 2021年第4期40卷 987-994页

作者： Xiang Chen Chao ni The College of Physics and Electronic Information Engineering Neijiang Normal UniversityNeijiang 641002China The Ames laboratory U.S.Department of EnergyIowa State UniversityAmesIA 50011-3020USA

The isothermal section of the Ho-Fe-In system at 773 K has been constructed by X-ray powder *** known structure ternary compound Er_(12)Fe_(2) In_(3)-type Ho_(12)Fe_(2) In_(3) has been *** the same time,solid solutions are not detected in Ho-Fe-In system at 773 *** magnetic transition and magnetocaloric effect of Ho_(12)Fe_(2.08)In_(2.92) alloy with Er_(12)Fe_(2) In_(3)-type structure were investigated by magnetic susceptibility and isothermal magnetization *** normal antiferromagnetic-paramagnetic transition and another abnormal one are discovered at 18 and 76 K in ground state,*** to a first-order field-induced metamagnetic transition(antiferromagnetic-ferromagnetic) at/below the Neel temperature of 18 K),the negative entropy changes are observed at corresponding *** is only a second-order ferromagnetic-paramagnetic transition near Curie temperature(TC),the maximum entropy change(Δ_(Smax)) values are-6.14 J·kg^(-1)·K^(-1) at 3 K and 7.88 J·kg^(-1)·K^(-1) at 28 K in a field range of 0-7 *** reversible relative cooling power corresponding to negative entropy change can reach about 600 J·kg^(-1) in an wide operating temperature region Δ_(Tcycl)=74 K from 16 to90 K,which suggests that Ho_(12)Fe_(2.08)In_(2.92) could be a potential material for magnetic refrigeration in the corresponding temperature range.

关键词： Re_(3(x+y))(T2)_(x)X_(y)phase Metamagnetic transition Magnetothermal properties Ho-Fe-In alloy

Elastic interaction between inclusions and tunable periodicity of superlattice structure in nanowires

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Applied Mathematics and Mechanics(English Edition) 2020年第10期41卷 1461-1478页

作者： Yang YANG Yong ni CAS Key laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsUniversity of Science and Technology of ChinaHefei 230026China

The elastic stress distribution and the variation of the elastic energy with spacing between two inclusions of arbitrary sizes in an infinite isotropic cylindrical rod are obtained by an analytical approach and the phase field microelasticity(PFM)*** results show a near-attraction and far-repulsion elastic interaction between two inclusions with hydrostatic *** critical spacing,at which the interaction changes from attraction to repulsion,is on the order of the radius of the rod,dependent on the length and Poisson’s ratio of ***,the elastic energy calculations and PFM simulation results indicate that applying the local radial stress on the rod surface can modulate the elastic interaction between inclusions and adjust the periodicity of the superlattice nanowire *** can provide some guidelines for the tunable construction of superlattice nanowire structures.

关键词： elastic interaction inclusion critical spacing superlattice structure

Unification of General Relativity with Quantum Field Theory

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Chinese Physics letters 2011年第11期28卷 24-27页

作者： ni Jun Department of Physics Tsinghua UniversityBeijing 100084

In the frame of quantum field theory,instead of using the action principle,we deduce the Einstein equation from purely the general covariant principle and the homogeneity of *** Einstein equation is shown to be the gauge equation to guarantee the local symmetry of spacetime *** is an apparent force due to the curvature of spacetime resulted from the conservation of *** the action of quantum field theory,only electroweak-strong interactions should be considered with the curved spacetime metric determined by the Einstein equation.

关键词： equation Einstein equation