3,771 research outputs found
Anharmonic effect on lattice distortion, orbital ordering and magnetic properties in Cs2AgF4
We develop the cluster self-consistent field method incorporating both
electronic and lattice degrees of freedom to study the origin of ferromagnetism
in CsAgF. After self-consistently determining the harmonic and
anharmonic Jahn-Teller distortions, we show that the anharmonic distortion
stabilizes the staggered x-z/y-z orbital and
ferromagnetic ground state, rather than the antiferromagnetic one. The
amplitudes of lattice distortions, Q and Q, the magnetic coupling
strengthes, J, and the magnetic moment, are in good agreement with the
experimental observation.Comment: 13 pages, 5 figure
(E)-Ethyl N′-(3-hydroxybenzylidene)hydrazinecarboxylate dihydrate
The asymmetric unit of the title compound, C10H12N2O3·2H2O, contains two organic molecules with similar conformations and four water molecules. Each organic molecule is close to planar (r.m.s. deviations = 0.035 and 0.108 Å) and adopts a trans conformation with respect to its C=N bond. In the crystal, the components are linked into a three-dimensional network by N—H⋯O, O—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds, some of which are bifurcated. An R
2
2(8) loop occurs between adjacent organic molecules
Placement study of composite vibration isolation system for machinery equipment
In traditional vibration isolation and placement
studies, vibration participation of foundation is
often ignored, and optimizations are focused on the
improvements of isolated object and isolation
system. In this paper, clamped thin plate was
considered as the foundation, and "machinery
equipment vibration isolator foundation" was
proposed as a composite vibration isolation
system. Based on the theory of mechanical fourpole
connection, transmitted force from equipment
to plate was derived, and the intermediate variable
was the displacement admittance of contact points
(isolators) on the plate. To peruse the optimal
placement, a novel procedure has been
programmed, and two cases of arrangement
direction have been involved. This study could give
a lot of inspiration for vibration isolation and
placement strategies of engineering equipment so
that extended researches based on this could be
performed
Multi-objective optimization of parameters and location of passive vibration isolation system excited by clamped thin plate foundation
This paper reports a novel optimization strategy combined with artificial intelligence for parameters and location design of precision equipment and provides a broader view for traditional passive vibration isolation. It also considers "precision equipment-vibration isolators-thin plate foundation" as a composite passive vibration isolation system and the clamped thin plate. The vibration isolation system is considered as four-point support, and the displacement amplitude transmissibility from the thin plate to precision equipment is derived and based on the analysis of influencing factors of transmissibility; subsequently, multi-objective optimization of the composite system is performed. A novel swarm intelligence multi-objective optimization method—a multi-objective particle swarm optimization (MOPSO) algorithm is adopted in this paper which can achieve a global optimal solution and by selecting the desired solution from an equivalence relation, the whole Pareto set can be avoided. The maximum and variance of the four transmitted peak displacements are simultaneously considered as fitness functions, and the purpose is to reduce the amplitude of the multi-peak isolation system, and in the meantime, to allow the plate to be uniformly vibrated as far as possible. Moreover, the presented idea is validated numerically, and the location research of the precision equipment mounted on the plate is also conducted
Absorption, Distribution and Excretion of 14C-Probimane in Mice Bearing Lewis Lung Carcinoma
Spontaneous neoplasm metastasis, a fatalist pathological feature of cancer, is a long-evolving, multi-steps process that can now only be treated or controlled by drugs or immuno-modulators. Probimane (Pro), as a representative of the well-known class of antimetastatic agents ‘Bisdioxopiperazine compounds (Biz)’, is systematically studied for its absorption, distribution and excretion in mice bearing Lewis lung carcinoma by a radioactivity-detective method in this investigation. It is found that the 14C-Pro concentrations in different normal organs of mice at 2 hrs are very high and dramatically declined at 24 and 48 hrs. However, Pro concentrations in metastatic foci are slightly changed at the same time. Almost no change of Pro concentrations is observed in pulmonary metastatic nodules within 48 hrs. This evidence can be used to explain the characteristics of good metastatic inhibition by Biz compounds. The radioactivity in brain is relatively low because Pro can hardly penetrate into the blood-brain-barrier to eliminate brain tumors. The excretion of 14C-Pro is observed at the same ratios from both urine and feces and also at constant rates. These data are much useful for better understanding of the general pharmacological characters and possible antimetastatic mechanisms of actions of probimane and other Biz compounds from a new perspective and research angles
Different Spontaneous Pulmonary Metastasis Inhibitions against Lewis Lung Carcinoma in Mice by Bisdioxopiperazine Compounds of Different Treatment Schedules
Spontaneous neoplasm metastasis, a fatalist pathological feature of cancer, is a long-evolving, multi-steps process that can now only be treated or controlled by drugs or immuno-modulators. As we have previously hypothesized, each drug or immuno-modulator might act differently within various stages of a metastasis. Therefore any researches helping to determine these differences will be beneficial for updating therapeutics for metastasis. In this work, we have testified this hypothesis by using a series of well-known anti-metastatic agents – Bisdioxopiperazine compounds
Electronic structure, mechanical and thermodynamic properties of ThN from first-principles calculations
Lattice parameter, electronic structure, mechanical and thermodynamic
properties of ThN are systematically studied using the projector-augmented-wave
method and the generalized gradient approximation based on the density
functional theory. The calculated electronic structure indicates the important
contributions of Th 6\emph{d}and 5\emph{f} states to the Fermi-level electron
occupation. Through Bader analysis it is found that the effective valencies in
ThN can be represented as Th N. Elastic constant
calculations shows that ThN is mechanically stable and elastically anisotropic.
Furthermore, the melting curve of ThN is presented up to 120 GPa. Based on the
phonon dispersion data, our calculated specific heat capacities including both
lattice and conduction-electron contributions agree well with experimental
results in a wide range of temperature.Comment: 16 pages, 8 figure
Plasmoid ejection and secondary current sheet generation from magnetic reconnection in laser-plasma interaction
Reconnection of the self-generated magnetic fields in laser-plasma
interaction was first investigated experimentally by Nilson {\it et al.} [Phys.
Rev. Lett. 97, 255001 (2006)] by shining two laser pulses a distance apart on a
solid target layer. An elongated current sheet (CS) was observed in the plasma
between the two laser spots. In order to more closely model magnetotail
reconnection, here two side-by-side thin target layers, instead of a single
one, are used. It is found that at one end of the elongated CS a fan-like
electron outflow region including three well-collimated electron jets appears.
The ( MeV) tail of the jet energy distribution exhibits a power-law
scaling. The enhanced electron acceleration is attributed to the intense
inductive electric field in the narrow electron dominated reconnection region,
as well as additional acceleration as they are trapped inside the rapidly
moving plasmoid formed in and ejected from the CS. The ejection also induces a
secondary CS
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