检索结果-南通市图书馆

Stability of Macroscopic Binary Systems

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2019年第11期71卷 1335-1340页

作者： G.G.Adamian n.v.Antonenko H.Lenske v.v.Sargsyan Joint Institu te for nuclear Research 141980 DubnaRussia Ins titut fur Theore tische Physik der Jus tus-Liebig—Uni versit nt D-35392 GiessenGermany

The Darwin instability effect in the binary systems(di-planets, di-stars, and di-galaxies) is analyzed within the model based on the Regge-like laws. All possible binary stars are found satisfying the Darwin instability condition that requires to search for other mechanism triggering the merger of the contact binary objects. new analytical formulas are obtained for the orbital rotation period and the relative distance between components of the binary system. The decreasing and increasing periods as functions of mass asymmetry are related, respectively, with the non-overlapping and overlapping stage of the binary object evolution.

关键词： Regge laws binary stars and galaxies Darwin instability effect

nEAR-InFRARED MOnITORInG OF THE LUMBAR ERECTOR SPInAE MUSCLE In HEALTHY MEn AnD WOMEn DURInG STATIC AnD DYnAMIC EnDURAnCE WORK

在线全文

学校读者我要写书评

暂无评论

Journal of Innovative Optical Health Sciences 2011年第2期4卷 173-182页

作者： RAMMOHAn v.MAIKALA YAGESH n.BHAMBHAnIy Liberty Mutual Research Institute for Safety 71 Frankland Road HopkintonMA 01748USA Faculty of Rehabilitation Medicine University of Alberta Edmonton Alberta T6G 2G4Canada

Understanding muscle hemodynamics using near-infrared spectroscopy is increasingly evident in the recent spinal disorders-related ***,none of these human studies addressed the issue of physiological limits for the lumbar muscle within the same participants during various exercise *** purpose of this study is to evaluate physiological limits for the lumbar muscle during dynamic and static endurance *** three separate days,22 healthy men and women performed three endurance protocols(static prone trunk extension,arm cranking,and pushingpulling)until volitional *** each protocol,minimum and maximum oxygenation and blood volume responses from the right lumbar erector spinae were obtained using a continuous dual wavelength near-infrared spectroscopy(Micro-Runman,nIM Inc.,PA,USA).Statistical analysis showed that greatest reduction in oxygenation(minimum)were obtained during dynamic exercises:pushingpulling(2.1 times)and arm cranking(2.03 times)versus static test (Pnge(calculated as the difference between maximum during recovery and minimum at the point of volitional exhaustion)during static test was lower[(66-75%for oxygenation)and(34-46%for blood volume)]than dynamic exercises (Pntrary to the theory that sufficient occlusion of bloodflow to the lumbar muscle is possible with static trunk extension,it was concluded that a dynamic protocol until volitional exhaustion might be a good alternative in establishing near-infrared spectroscopy-derived physiological limits to the lumbar *** research is essential to identify an optimal calibration procedure for establishing true hypoxic values for the human lumbar muscle.

关键词： Arm cranking back muscle endurance gender differences oxygenation and blood volume pushingpulling Sorensen test

Seasonal Dynamics of Male and Female Reproductive Systems in the Siberian Salamander, Salamandrella keyserlingii (Caudata, Hynobiidae)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Herpetological Research 2015年第3期6卷 169-183页

作者： vadim v.YARTSEv valentina n.KURAnOvA Department of vertebrate Zoology and Ecology Institute of BiologyTomsk State University

It is not well known how low temperatures, like a subarctic steppe–tundra climate, influence reproductive traits of ectothermic vertebrates. To begin answering this question, we studied male and female reproductive systems of Salamandrella keyserlingii inhabiting a Tomsk population（southeast of Western Siberia）, Russia, in ecological and physiological terms. In males, before spermiation, the testicular size and weight in late April–early May were greatest of all. Spermiation occurred during breeding immigration in spring when mean air temperature was above 10°С, and at the same time rain fell. After spermiation, the testicular size and weight decreased sharply, and the diameter of the vasa deferentia increased. ＂Spawning＂（i.e., simultaneous extrusion of sperm and oviposition） occurred from late April to late May, and this duration fluctuated in temperature and humidity. The testicular size and weight increased in summer. Sperm mass was detected in the testes by the smear method in April–September, except in June when single fragmented unrealized sperm was detected and in July when spermatids were detected. In females, ovarian weight was greatest in spring before ovulation. From late June, vitellogenesis began in ovarian follicles, in which mint green yolks accumulated. Melanin deposited in the surface of the ovary from July when oviducts were hypertrophying. In contrast, some large-sized females did not show any sexual maturity shortly before hibernation（although these females may be subadults）. These results suggest that low temperatures in Siberia induce early timing of gamete maturation in females, but the females＇ reproductive cycle might also be biennial. A reproductive cycle in males was annual with the completion of the gamete maturation process in August.

关键词： annual reproductive cycle biennial reproductive cycle breeding immigration gamete maturation subarctic climate

What is the difference between marine and limnetic-terrestrial associations of nematodes with invertebrates?

在线全文

学校读者我要写书评

暂无评论

Integrative Zoology 2022年第4期17卷 481-510页

作者： Alexei v.TCHESUnOv viatcheslav n.IvAnEnKO Department of Invertebrate Zoology Faculty of BiologyM.V.Lomonosov Moscow State UniversityMoscowRussia

Zoo-and phyto-parasitic nematodes of the order Rhabditida and zooparasites of the subclass Dorylaimia are well known,due largely to their medical,veterinarian and agricultural ***,there have been many switches from a free-living to a symbiotic(including parasitism)mode of existence in the evolutionary trajectories of various nematode ***,we attempt to summarize all known cases of symbioses(from commensalism to true parasitism)between marine nematodes representing nonparasitic taxa and various larger animals,ranging from protists to *** cases are of nematodes relating to dwelling on crustaceans(ectocommensalism)or living in the body cavity and internal organs of various invertebrates(endoparasitism or parasitoidism).Ectocommensal species may differ from their free-living relatives in their longer filiform bodies and enlarged ventral and caudal glands,which may be interpreted as adaptations for the purpose of fixation on the body surface of a motile *** species are characterized by deep anatomical modification,including rudimentation of the alimentary tract and hypertrophy of reproductive *** terrestrial and limnetic invertebrates,marine invertebrates have almost no intestinal nematode *** evolutionary trajectories of nematode dwellers of marine and nonmarine invertebrates are compared.

关键词： commensalism marine invertebrates nematoda parasitism symbiosis

Measurement of the spatial specific impulse distribution due to buried high explosive charge detonation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2017年第3期13卷 219-227页

作者： v. Denefeld n. Heider A. Holzwarth Fraunhofer Institute for High-Speed Dynamics Ernst-Mach-Institut EMI Ernst-Mach-Institut

Buried high explosive(HE) charges represent a high threat to military vehicles. The detonation of these charges can lead to significant momentum transfer onto vehicles and their occupants. A detailed understanding of the physical processes involved in the loading of vehicle structures is necessary for an optimization of effective countermeasures and protection systems. A quantitative description of the local momentum distribution on the vehicle underbody due to the detonation process is of special importance. In the following, a new test setup is presented that allows the experimental determination of the specific impulse distribution. It is based on a ring arrangement where the elements are nested into each other and the velocity of each ring is correlated with the local specific impulse at its *** momentum transfer to a vehicle depends on a number of influencing factors such as: charge mass,embedding material(e.g. sand, gravel, clay), density, water content, saturation, depth of burial, ground clearance and vehicle shape. The presented technology is applied to quantify the influence of the embedding material(alluvial sand, quartz sand), the burial depth and the water content on the local specific impulse distribution. The obtained data can be used as initial condition for the numerical simulation of occupant safety assessment and as input for empirical modeling of momentum transfer on structures.

关键词：装药爆炸比冲军用车辆测量空间炸药车辆结构包埋材料

Mean-Square Approximation of navier-Stokes Equations with Additive noise in vorticity-velocity Formulation

在线全文

学校读者我要写书评

暂无评论

numerical Mathematics(Theory,Methods and Applications) 2021年第1期14卷 1-30页

作者： G.n.Milstein M.v.Tretyakov Ural Federal University EkaterinburgRussia School of Mathematical Sciences University of NottinghamNottinghamUK

We consider a time discretization of incompressible navier-Stokes equations with spatial periodic boundary conditions and additive noise in the vorticity-velocity *** approximation is based on freezing the velocity on time subintervals resulting in a linear stochastic parabolic equation for *** each time step,the velocity is expressed via vorticity using a formula corresponding to the Biot-Savart-type *** prove the first mean-square convergence order of the vorticity approximation.

关键词： navier-Stokes equations vorticity numerical method stochastic partial differential equations mean-square convergence

new-type internal target for structural ion stripping

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics C 2018年第1期42卷 151-156页

作者： D.n.Makarov v.I.Matveev Federal Center for Integrated Arctic Research Russian Academy of Sciences Arkhangelsk 163000 Russia northern (Arctic) Federal University Arkhangelsk 163002 Russia

The search is now on for new materials that can be used for ionic stripping. Materials that maximize the stripping of the structural ion are important for conducting experiments with quark-gluon plasma. Although this paper is a theoretical study, it offers practical applications, in heavy-ion accelerators, of the new effect of collision multiplicity with high-energy ions interacting with polyatomic targets. It is shown that internal nanostructured targets in which the collision multiplicity effect is manifested can more efficiently strip out structural ions compared to standard internal targets for stripping. A target consisting of oriented nano-tubes with the C_（240） chirality（10,0）is considered as an example. A comparison with the stripping process on a carbon target with the same number of misaligned atoms in a unit of volume C is provided.

关键词： ion stripping accelerator target ion beam nanotube charge composition

Optically read Coriolis vibratory gyroscope based on a silicon tuning fork

在线全文

学校读者我要写书评

暂无评论

Microsystems & nanoengineering 2019年第1期5卷 174-184页

作者： n.v.Lavrik P.G.Datskos Center for nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTN 37931-6054USA Mechanical and Thermal Engineering Sciences National Renewable Energy LaboratoryGoldenCO 80401USA

In this work,we describe the design,fabrication,and characterization of purely mechanical miniature resonating structures that exhibit gyroscopic performance comparable to that of more complex microelectromechanical *** to previous implementations of Coriolis vibratory gyroscopes,the present approach has the key advantage of using excitation and probing that do not require any on-chip electronics or electrical contacts near the resonating *** specifically,our design relies on differential optical readout,each channel of which is similar to the“optical lever”readout used in atomic force *** piezoelectrically actuated stage provides highly efficient excitation of millimeter-scale tuning fork structures that were fabricated using widely available high-throughput waferlevel silicon *** our experiments,reproducible responses to rotational rates as low as 1.8×10^(3)°h^(−1)were demonstrated using a benchtop prototype without any additional processing of the raw *** noise-equivalent rate,Ω_(nER),derived from the Allan deviation plot,was found to bevely low Q factors(ning fork structures operating under ambient pressure and temperature conditions,the measured performance was not limited by thermomechanical *** fact,the performance demonstrated in this proof-of-principle study is approximately four orders of magnitude away from the fundamental limit.

关键词： structure excitation proof

Pulsed laser reshaping and fragmentation of upconversion nanoparticles-from hexagonal prisms to ID nanorods through“Medusa”-like structures

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

nano Research 2021年第4期14卷 1141-1148页

作者： Laszlo Sajti Denis n.Karimov vasilina v.Rocheva nataliya A.Arkharova Kirill v.Khaydukov Oleg I.Lebedev Alexey E.voloshin Alla n.Generalova Boris n.Chichkov Evgeny v.Khaydukov AIT Austrian Institute of Technology GmbH Wiener Neustadt2700Austria Federal Scientific Research Centre“Crystallography and Photonics”Russian Academy of Sciences Moscow119333Russia Laboratoire CRISMAT UMR6508CNRS-ENSIACENUniversite CaenCaen14050France Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences Moscow 117997Russia Institutfiir Quantenoptik Leibniz Universitat HannoverHannover30167Germany Center of Biomedical Engineering Institute of Molecular Medicine Sechenov First Moscow State Medical UniversityMoscow119991Russia

One dimensional(1D)nanostructures attract considerable attention,enabling a broad application owing to their unique ***,the precise mechanism of 1D morphology attainment remains a matter of *** this study,ultrafast picosecond(ps)laser-induced treatment on upconversion nanoparticles(UCnPs)is offered as a tool for 1 D-nanostructures ***,reshaping through recrystallization process and bioadaptation of initially hydrophobic(β-na_(1.5)Y_(1.5_)F_(6):Yb^(3+),Tm^(3+)/β-na_(1.5)Y_(1.5_)F_(6))core/shell nanoparticles by means of one-step laser treatment in water are demonstrated.“True”1D nanostructures through"Medusa^-like structures can be obtained,maintaining anti-Stokes luminescence functionalities.A matter of the one-dimensional UCnPs based on direction of energy migration processes is *** proposed laser treatment approach is suitable for fast UCnP surface modification and nano-to-nano transformation,that open unique opportunities to expand UCnP applications in industry and biomedicine.

关键词： upconversion nanoparticles fluoride crystals upconversion nanorods one-dimensional(1D)structures laser-induced reshaping