48,494 research outputs found

### The surface diffuseness and the spin-orbital splitting in relativistic continuum Hartree-Bogoliubov theory

The Relativistic Continuum Hartree Bogoliubov theory (RCHB), which is the
extension of the Relativistic Mean Field and the Bogoliubov transformation in
the coordinate representation, has been used to study tin isotopes. The pairing
correlation is taken into account by a density-dependent force of zero range.
RCHB is used to describe the even-even tin isotopes all the way from the proton
drip line to the neutron drip line. The contribution of the continuum which is
important for nuclei near the drip-line has been taken into account. The
theoretical $S_{2n}$ as well as the neutron, proton, and matter $rms$ radii are
presented and compared with the experimental values where they exist. The
change of the potential surface with the neutron number has been investigated.
The diffuseness of the potentials in tin isotopes is analyzed through the
spin-orbital splitting in order to provide new way to understand the halo
phenomena in exotic nuclei. The systematic of the isospin and energy dependence
of these results are extracted and analyzed.Comment: 11 figure

### Particles in classically forbidden area, neutron skin and halo, and pure neutron matter in Ca isotopes

The nucleon density distributions and the thickness of pure neutron matter in
Ca isotopes were systematically studied using the Skyrme-Hartree-Fock model
(SHF) from the $\beta$-stability line to the neutron drip-line. The pure
neutron matter, related with the neutron skin or halo, was shown to depend not
only on the Fermi levels of the neutrons but also on the orbital angular
momentum of the valence neutrons. New definitions for the thickness of pure
neutron matter are proposed.Comment: 6 pages, 5 figure

### The relativistic continuum Hartree-Bogoliubov description of charge-changing cross section for C,N,O and F isotopes

The ground state properties including radii, density distribution and one
neutron separation energy for C, N, O and F isotopes up to the neutron drip
line are systematically studied by the fully self-consistent microscopic
Relativistic Continuum Hartree-Bogoliubov (RCHB) theory. With the proton
density distribution thus obtained, the charge-changing cross sections for C,
N, O and F isotopes are calculated using the Glauber model. Good agreement with
the data has been achieved. The charge changing cross sections change only
slightly with the neutron number except for proton-rich nuclei. Similar trends
of variations of proton radii and of charge changing cross sections for each
isotope chain is observed which implies that the proton density plays important
role in determining the charge-changing cross sections.Comment: 10 pages, 4 figure

### Pseudospin symmetry and its approximation in real nuclei

The origin of pseudospin symmetry and its broken in real nuclei are discussed
in the relativistic mean field theory. In the exact pseudospin symmetry, even
the usual intruder orbits have degenerate partners. In real nuclei, pseudospin
symmetry is approximate, and the partners of the usual intruder orbits will
disappear. The difference is mainly due to the pseudo spin-orbit potential and
the transition between them is discussed in details. The contribution of
pseudospin-orbit potential for intruder orbits is quite large, compared with
that for pseudospin doublets. The disappearance of the pseudospin partner for
the intruder orbit can be understood from the properties of its wave function.Comment: 10 pages, 3 figure

### Succinct Representations of Dynamic Strings

The rank and select operations over a string of length n from an alphabet of
size $\sigma$ have been used widely in the design of succinct data structures.
In many applications, the string itself need be maintained dynamically,
allowing characters of the string to be inserted and deleted. Under the word
RAM model with word size $w=\Omega(\lg n)$, we design a succinct representation
of dynamic strings using $nH_0 + o(n)\lg\sigma + O(w)$ bits to support rank,
select, insert and delete in $O(\frac{\lg n}{\lg\lg n}(\frac{\lg \sigma}{\lg\lg
n}+1))$ time. When the alphabet size is small, i.e. when \sigma = O(\polylog
(n)), including the case in which the string is a bit vector, these operations
are supported in $O(\frac{\lg n}{\lg\lg n})$ time. Our data structures are more
efficient than previous results on the same problem, and we have applied them
to improve results on the design and construction of space-efficient text
indexes

### Technology of swallowable capsule for medical applications

Medical technology has undergone major breakthroughs in recent years, especially in the area of the examination tools for diagnostic purposes. This paper reviews the swallowable capsule technology in the examination of the gastrointestinal system for various diseases. The wireless camera pill has created a more advanced method than many traditional examination methods for the diagnosis of gastrointestinal diseases such as gastroscopy by the use of an endoscope. After years of great innovation, commercial swallowable pills have been produced and applied in clinical practice. These smart pills can cover the examination of the gastrointestinal system and not only provide to the physicians a lot more useful data that is not available from the traditional methods, but also eliminates the use of the painful endoscopy procedure. In this paper, the key state-of-the-art technologies in the existing Wireless Capsule Endoscopy (WCE) systems are fully reported and the recent research progresses related to these technologies are reviewed. The paper ends by further discussion on the current technical bottlenecks and future research in this area

### Asymptotics of neutron Cooper pair in weakly bound nuclei

Asymptotic form of neutron Cooper pair penetrating to the exterior of nuclear
surface is investigated with the Bogoliubov theory for the superfluid Fermions.
Based on a two-particle Schr\"{o}dinger equation governing the Cooper pair wave
function and systematic studies for both weakly bound and stable nuclei, the
Cooper pair is shown to be spatially correlated even in the asymptotic large
distance limit, and the penetration length of the pair condensate is revealed
to be universally governed by the two-neutron separation energy $S_{2n}$ and
the di-neutron mass $2m$

### The proton and neutron distribution in Na isotopes: the development of halo and shell structure

The interaction cross sections for $^A Na + ^{12}C$ reaction are calculated
using Glauber model. The continuum Hartree-Bogoliubov theory has been
generalized to treat the odd particle system and take the continuum into
account. The theory reproduces the experimental result quite well. The matter
distributions from the proton drip line to the neutron drip line in Na isotopes
have been systematically studied and presented. The relation between the shell
effects and the halos has been examined. The tail of the matter distribution
shows a strong dependence on the shell structure. The neutron N=28 closure
shell fails to appear due to the coming down of the $2p_{3/2}$ and $2p_{1/2}$.
The development of the halo was understood as changes in the occupation in the
next shell or the sub-shell close to the continuum limit. The central proton
density is found to be decreasing near the neutron drip line, which is due to
the proton-neutron interaction. However the diffuseness of the proton density
does not change for the whole Na isotopes.Comment: 10 pages, 4 figure

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