7,089,949 research outputs found
Turing computability, probability, and prime numbers
We present an original theoretical approach to prove that almost certainly stands, where is the
number of primes not greater than , is a logarithmic integral
function, and is an arbitrary function such that
.Comment: Revision of the contents over the whole range of the pape
A proof of the Riemann hypothesis based on the Koch theorem, on primes in short intervals, and distribution of nontrivial zeros of the Riemann zeta function
Part One: Let define the truncation of the logarithmic integral as First, we
prove which implies that the point of
the truncation depends on x, Next, let . We prove
that is greater than for and tends to
as . Thirdly, we prove Finally, we prove
Part Two: Let define where we proved that the pair of
numbers and in satisfy inequalities
, and the number is approximately a
step function of the variable with a finite amount of deviation, and
proportional to . We obtain much more accurate estimation
of prime numbers, the error range of which is less than
for or less than for
.
Part Three: We show the closeness of and and give the
difference being less than or equal to where
is a constant. Further more, we prove the estimation
. Hence we obtain so
that the Riemann hypothesis is true.
Part Four: Different from former researches on the distribution of primes in
short intervals, we prove a theorem: Let , ,
and which satisfies . Then there are and Comment: 95 page
Quasiparticle electronic band structure of the alkali metal chalcogenides
The electronic energy band spectra of the alkali metal chalcogenides MA
(M: Li, Na, K, Rb; A: O, S, Se, Te) have been evaluated within the projector
augmented waves (PAW) approach by means of the ABINIT code. The Kohn-Sham
single-particle states have been found in the GGA (the generalized gradient
approximation) framework. Further, on the basis of these results the
quasiparticle energies of electrons as well as the dielectric constants were
obtained in the GW approximation. The calculations based on the Green's
function have been originally done for all the considered MA crystals,
except LiO.Comment: 8 pages, 8 figure
Lithium in the Intermediate-Age Open Cluster, NGC 3680
High-dispersion spectra centered on the Li 6708 A line have been obtained for
70 potential members of the open cluster NGC 3680, with an emphasis on stars in
the turnoff region. A measurable Li abundance has been derived for 53 stars, 39
of which have radial velocities and proper motions consistent with cluster
membership. After being transferred to common temperature and abundance scales,
previous Li estimates have been combined to generate a sample of 49 members, 40
of which bracket the cluster Li-dip. Spectroscopic elemental analysis of 8
giants and 5 turnoff stars produces [Fe/H] = -0.17 +/- 0.07 (sd) and -0.07 +/-
0.02 (sd), respectively. We also report measurements of Ca, Si and Ni which are
consistent with scaled-solar ratios within the errors. Adopting [Fe/H] = -0.08
(Sect. 3.6), Y^2 isochrone comparisons lead to an age of 1.75 +/- 0.10 Gyr and
an apparent modulus of (m-M) = 10.30 +/- 0.15 for the cluster, placing the
center of the Li-dip at 1.35 +/- 0.03 solar masses. Among the giants, 5 of 9
cluster members are now known to have measurable Li with A(Li) near 1.0. A
combined sample of dwarfs in the Hyades and Praesepe is used to delineate the
Li-dip profile at 0.7 Gyr and [Fe/H] = +0.15, establishing its center at 1.42
+/- 0.02 solar masses and noting the possible existence of secondary dip on its
red boundary. When evolved to the typical age of the clusters NGC 752, IC 4651
and NGC 3680, the Hyades/Praesepe Li-dip profile reproduces the observed
morphology of the combined Li-dip within the CMD's of the intermediate-age
clusters while implying a metallicity dependence for the central mass of the
Li-dip given by Mass = (1.38 +/-0.04) + (0.4 +/- 0.2)[Fe/H]. The implications
of the similarity of the Li-dichotomy among giants in NGC 752 and IC 4651 and
the disagreement with the pattern among NGC 3680 giants are discussed.Comment: Latex ms. is 56 pages, including 10 figures and 4 tables. Accepted
for the Astronomical Journa
The Median Largest Prime Factor
Let denote the median largest prime factor of the integers in the
interval . We prove that
where . From this, we obtain the asymptotic
where is the Euler Mascheroni constant. This answers a
question posed by Martin, and improves a result of Selfridge and Wunderlich.Comment: 7 page
Nonflammable Lithium Metal Full Cells with Ultra-high Energy Density Based on Coordinated Carbonate Electrolytes
Coupling thin Li metal anodes with high-capacity/high-voltage cathodes such as LiNi0.8Co0.1Mn0.1O2 (NCM811) is a promising way to increase lithium battery energy density. Yet, the realization of high-performance full cells remains a formidable challenge. Here, we demonstrate a new class of highly coordinated, nonflammable carbonate electrolytes based on lithium bis(fluorosulfonyl)imide (UFSI) in propylene carbonate/fluoroethylene carbonate mixtures. Utilizing an optimal salt concentr ation (4 M LiFSI) of the electrolyte results in a unique coordination structure of Li+-FSI-solvent cluster, which is critical for enabling the formation of stable interfaces on both the thin Li metal anode and high-voltage NCM811 cathode. Under highly demanding cell configuration and operating conditions (Li metal anode = 35 mu m, areal capacity/charge voltage of NCM811 cathode = 4.8 mAh cm(-2)/4 .6 V, and anode excess capacity [relative to the cathode] = 0.83), the Li metal-based full cell provides exceptional electrochemical performance (energy densities = 679 Wh kg(cell)(-1)/1,024 Wh L-cell(-1)) coupled with nonflammability
Magnetic and Electronic Properties of LiCoO Single Crystals
Measurements of electrical resistivity (), DC magnetization () and
specific heat () have been performed on layered oxide LiCoO
(0.250.99) using single crystal specimens. The versus
temperature () curve for =0.90 and 0.99 is found to be insulating but a
metallic behavior is observed for 0.250.71. At 155 K, a sharp anomaly is observed in the , and
curves for =0.66 with thermal hysteresis, indicating the
first-order charactor of the transition. The transition at 155
K is observed for the wide range of =0.460.71. It is found that the
curve measured after rapid cool becomes different from that after
slow cool below , which is 130 K for =0.460.71. is found to agree with the temperature at which the motional narrowing in
the Li NMR line width is observed, indicating that the Li ions stop
diffusing and order at the regular site below . The ordering of Li
ions below 130 K is likely to be triggered and stabilized by
the charge ordering in CoO layers below .Comment: 8 pages, 7 figure
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