99 research outputs found
Investigation of technological process zavaltsyuvannya balls in guiding transport mechanisms
Наведено конструкцію і принцип роботи пристрою для завальцювання кульок у направляючих у транспортних механізмах з попередньо підготовленим базовим отвором. Виведено аналітичні залежності для визначення силових, конструктивних і технологічних параметрів при завальцюванні кульок у транспортних направляючих парах тертя кочення, виготовлених з різних матеріалів.Present structure and principle of the device for zavaltsyuvannya balls in guiding the transport mechanisms of pre-prepared base hole. The derived analytical dependences for determination of power, structural and technological parameters in the balls by rolling in the transport steam rollingguides manufactured from different materials
Blank assessment for ultra-small radiocarbon samples : chemical extraction and separation versus AMS
Author Posting. © Arizona Board of Regents on behalf of the University of Arizona, 2010. This article is posted here by permission of Dept. of Geosciences, University of Arizona for personal use, not for redistribution. The definitive version was published in Radiocarbon 52 (2010): 1322-1335.The Keck Carbon Cycle AMS facility at the University of California, Irvine (KCCAMS/UCI) has developed
protocols for analyzing radiocarbon in samples as small as ~0.001 mg of carbon (C). Mass-balance background corrections
for modern and 14C-dead carbon contamination (MC and DC, respectively) can be assessed by measuring 14C-free and modern
standards, respectively, using the same sample processing techniques that are applied to unknown samples. This approach
can be validated by measuring secondary standards of similar size and 14C composition to the unknown samples. Ordinary
sample processing (such as ABA or leaching pretreatment, combustion/graphitization, and handling) introduces MC contamination
of ~0.6 ± 0.3 μg C, while DC is ~0.3 ± 0.15 μg C. Today, the laboratory routinely analyzes graphite samples as small
as 0.015 mg C for external submissions and ≅0.001 mg C for internal research activities with a precision of ~1% for ~0.010
mg C. However, when analyzing ultra-small samples isolated by a series of complex chemical and chromatographic methods
(such as individual compounds), integrated procedural blanks may be far larger and more variable than those associated with
combustion/graphitization alone. In some instances, the mass ratio of these blanks to the compounds of interest may be so
high that the reported 14C results are meaningless. Thus, the abundance and variability of both MC and DC contamination
encountered during ultra-small sample analysis must be carefully and thoroughly evaluated. Four case studies are presented
to illustrate how extraction chemistry blanks are determined
Anisotropic Singular Integrals in Product Spaces
Let for be an expansive dilation, respectively, on and and . Denote by {\mathcal
A}_\infty(\rnm; \vec A) the class of Muckenhoupt weights associated with . The authors introduce a class of anisotropic singular integrals on , whose kernels are adapted to in the sense of
Bownik and have vanishing moments defined via bump functions in the sense of
Stein. Then the authors establish the boundedness of these anisotropic singular
integrals on with and
or on with and . These results are also new
even when .Comment: Sci. China Math., to appea
Reemerging superconductivity at 48 K across quantum criticality in iron chalcogenides
Pressure plays an essential role in the induction1 and control2,3 of
superconductivity in iron-based superconductors. Substitution of a smaller
rare-earth ion for the bigger one to simulate the pressure effects has
surprisingly raised the superconducting transition temperature Tc to the record
high 55 K in these materials4,5. However, Tc always goes down after passing
through a maximum at some pressure and the superconductivity eventually tends
to disappear at sufficiently high pressures1-3. Here we show that the
superconductivity can reemerge with a much higher Tc after its destruction upon
compression from the ambient-condition value of around 31 K in newly discovered
iron chalcogenide superconductors. We find that in the second superconducting
phase the maximum Tc is as high as 48.7 K for K0.8Fe1.70Se2 and 48 K for
(Tl0.6Rb0.4)Fe1.67Se2, setting the new Tc record in chalcogenide
superconductors. The presence of the second superconducting phase is proposed
to be related to pressure-induced quantum criticality. Our findings point to
the potential route to the further achievement of high-Tc superconductivity in
iron-based and other superconductors.Comment: 20 pages and 7 figure
Local Hardy Spaces of Musielak-Orlicz Type and Their Applications
Let \phi: \mathbb{R}^n\times[0,\fz)\rightarrow[0,\fz) be a function such
that is an Orlicz function and (the class of local weights
introduced by V. S. Rychkov). In this paper, the authors introduce a local
Hardy space of Musielak-Orlicz type by the local grand
maximal function, and a local -type space
which is further proved to be the
dual space of . As an application, the authors prove
that the class of pointwise multipliers for the local
-type space ,
characterized by E. Nakai and K. Yabuta, is just the dual of
L^1(\rn)+h_{\Phi_0}(\mathbb{R}^n), where is an increasing function on
satisfying some additional growth conditions and a
Musielak-Orlicz function induced by . Characterizations of
, including the atoms, the local vertical and the local
nontangential maximal functions, are presented. Using the atomic
characterization, the authors prove the existence of finite atomic
decompositions achieving the norm in some dense subspaces of
, from which, the authors further deduce some
criterions for the boundedness on of some sublinear
operators. Finally, the authors show that the local Riesz transforms and some
pseudo-differential operators are bounded on .Comment: Sci. China Math. (to appear
Collected Data for Tests on NACA 0015 Aerofoil with Chord of Length 0.275m. G.U. Aero Report 9209
Herein is presented the collected data for tests in which a NACA 0015 aerofoil with chord of length 0.275m, was subjected to a variety of displacements in pitch about the quarter-chord location at low Reynolds numbers
Collected Data for Tests on NACA 0015 Aerofoil with Chord of Length 0.275m. G.U. Aero Report 9209
Herein is presented the collected data for tests in which a NACA 0015 aerofoil with chord of length 0.275m, was subjected to a variety of displacements in pitch about the quarter-chord location at low Reynolds numbers
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