447 research outputs found
Strange Tribaryons as Nona-quark States
Strange tribaryons as nona-quark (9 quark) states is studied to describe the
S=-1 resonance S^0(3115) recently discovered in the reaction K- + ^4 He -> S^0
+ p. We have identified S^0(3115) as a member of the flavor 27-plet, in
particular, (F_{flavor},I_{isospin},J_{spin})=(27,1,1/2) or (27,1,3/2). The
color-magnetic interaction between quarks favors small multiplets in flavor and
spin, which leads to a natural explanation that I=1 is the lowest state among
the S=-1 tribaryons with J=1/2. Classification of the S^+ -state recently
reported as well as possible locations of other light strange tribaryons such
as (10*,0,3/2) with S=-1, (8,1/2,1/2) with S=-2 and (1,0,3/2) with S=-3 are
also discussed.Comment: 10 pages, 3 figure
Correlation in Relativistic Heavy Ion Collisions with Nucleon-Hyperon Interaction from Lattice QCD
On the basis of the interaction extracted from (2+1)-flavor lattice
QCD simulations at the physical point, the momentum correlation of and
produced in relativistic heavy ion collisions is evaluated. defined by a ratio of the momentum correlations between the systems
with different source sizes is shown to be largely enhanced at low momentum due
to the strong attraction between and in the channel. Thus,
measuring this ratio at RHIC and LHC and its comparison to the theoretical
analysis will give a useful constraint on the interaction.Comment: 4 pages, 2 figures; proceedings contribution for Quark Matter 201
Influence of 7.5% hydrogen peroxide containing calcium, ACP, fluoride and hydroxyapatite on microhardness, surface roughness, color change and micromorphology of human enamel
Orientador: Flávio Henrique Baggio AguiarDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O objetivo deste estudo in vitro foi determinar a microdureza, rugosidade superficial, micromorfologia e alterações de cor de esmalte dental humano submetido a tratamentos clareadores caseiros com peróxidos de hidrogênio a 7,5% (PH) adicionados de cálcio, fosfato de cálcio amorfo (ACP), flúor e/ou hidroxiapatita (HA). Três agentes de tratamento comerciais: (Pola Day 7,5% (PD), Day White ACP 7,5% (DW), White Class Calcium 7,5% (WC)), três agentes clareadores experimentais (PH 7,5% + NaF (PHF), PH 7,5% + HA (PHH) e PH 7,5% + NaF + HA (PHFH)) e os grupos controle positivo (gel de peróxido de hidrogênio a 7,5% - PC) e controle negativo (gel sem peróxido de hidrogênio a 7,5% - NC), foram avaliados (n=10). Os agentes de tratamento comerciais foram aplicados pelo prazo recomendado pelos fabricantes e os agentes experimentais por 1,5 hora por dia. Todas as amostras foram imersas em solução de saliva artificial pelo resto do dia, num total de 21 dias de tratamento. Após, ficaram armazenados em saliva artificial por 14 dias. Ensaios de microdureza, rugosidade superficial, micromorfologia do esmalte e análise de alteração de cor foram realizados nos tempos baseline, 7, 14, 21 dias de tratamento, 7 e 14 dias de pós-tratamento. Para análise estatística, as médias foram comparadas utilizando o teste de Tukey-Kramer com um nível de significância de 5%. Como resultados, no teste de rugosidade superficial (Ra) foi observado aumento em todos os grupos experimentais (PHF, PHH e PHFH) e nos grupos comerciais DW e WC ao longo do tempo. No teste de microdureza (KHN) observou-se um aumento significativo para o grupo PHH e redução significativa do grupo DW, enquanto os outros grupos não apresentaram alteração significativa ao longo do tempo de estudo. Para o teste de análise de alteração de cor, todos os agentes apresentaram efeito clareador, exceto o grupo NC, sendo que o grupo PHH foi o único que apresentou valores similares aos agentes clareadores comerciais em todos os tempos de estudo. Na análise morfológica observou-se alterações como a presença de porosidades na maioria dos grupos, exceto no grupo NC, além de deposição de cristais de hidroxiapatita nos grupos PHH e PHFH. Concluiu-se que o tratamento clareador contendo hidroxiapatita proporcionou alterações de cor similares aos agentes clareadores comerciais, foi capaz de aumentar a microdureza, e que quando este componente é formulado com ou sem flúor, pode levar a um aumento da rugosidade superficial, devido a deposição de cristais de hidroxiapatita na superfície de esmalte, como observado pela análise de microscopia eletrônica de varreduraAbstract: The aim of this in vitro study was to determine the microhardness, surface roughness, micromorphology and color change analysis of enamel submitted to with home-use bleaching treatment 7.5% hydrogen peroxide (HP) added with calcium, amorphous calcium phosphate (ACP), fluoride and/or hydroxyapatite (HA). Three commercial treatment agents: (Pola Day 7.5% (PD), Day White ACP 7.5% (DW), White Class 7.5% Calcium (WC)), three experimental bleaching agents (7.5% HP + NaF (PHF), HP + 7.5% HA (PHH) and PH + 7.5% NaF + HA (PHFH)), a negative control (Gel without 7.5% hydrogen peroxide - NC) and a positive control (Gel with 7.5% hydrogen peroxide - PC) groups were evaluated (n=10). The treatment agents were applied according to the manufacturer's recommendation and experimental agents were applied for 1,5 hour daily. Then all the specimens were immersed in artificial saliva for the rest of the day, in a total of 21 days of treatment. After the treatment phase, the specimens were stored in artificial saliva for 14 days. Microhardness tests, surface roughness, micromorphology of the enamel and color change analysis were performed at baseline, 7, 14, 21 days of treatment, 7 and 14 days post-treatment. For the statistical analysis, means were compared using the Tukey-Kramer test at a significance level of 5%. As results, the surface roughness test (Ra) presented increase in all experimental groups (PHF, PHH and PHFH) and commercial groups DW and WC in function of time. The microhardness test (KHN) showed a significant increase for the group PHH and a significant reduction on DW group, while the other groups did not show statistical difference in function of timespan study. For the color change analysis test, all the groups presented bleaching effectiveness, except the group NC, and the PHH group was the only one that showed similar values compared to the commercial bleaching agents at all times of study. In the morphological analysis, changes were observed as the presence of porosities in most groups, except on NC group, and deposition of hydroxyapatite crystals on groups PHH and PHFH. It was concluded that the bleaching treatment containing hydroxyapatite provided color changes similar to commercial bleaching agents, was able to increase the microhardness values, and that when this component is formulated with or without fluoride, it can lead to an increase in surface roughness due to deposition of hydroxyapatite crystals over the enamel surface, as observed by analysis of scanning electron microscopyMestradoDentísticaMestre em Clínica Odontológic
Complex Heavy-Quark Potential at Finite Temperature from Lattice QCD
We calculate for the first time the complex potential between a heavy quark
and antiquark at finite temperature across the deconfinement transition in
lattice QCD. The real and imaginary part of the potential at each separation
distance is obtained from the spectral function of the thermal Wilson loop.
We confirm the existence of an imaginary part above the critical temperature
, which grows as a function of and underscores the importance of
collisions with the gluonic environment for the melting of heavy quarkonia in
the quark-gluon-plasma.Comment: 4 pages, 3 figures, to be published in PR
Spectral Analysis of Excited Nucleons in Lattice QCD with Maximum Entropy Method
We study the mass spectra of excited baryons with the use of the lattice QCD
simulations. We focus our attention on the problem of the level ordering
between the positive-parity excited state N'(1440) (the Roper resonance) and
the negative-parity excited state N^*(1535). Nearly perfect parity projection
is accomplished by combining the quark propagators with periodic and
anti-periodic boundary conditions in the temporal direction. Then we extract
the spectral functions from the lattice data by utilizing the maximum entropy
method. We observe that the masses of the N' and N^* states are close for wide
range of the quark masses (M_pi=0.61-1.22 GeV), which is in contrast to the
phenomenological prediction of the quark models. The role of the Wilson
doublers in the baryonic spectral functions is also studied.Comment: 15 pages, 5 figures included, typos corrected, and references adde
Three-Dimensional Imaging Method Incorporating Range Points Migration and Doppler Velocity Estimation for UWB Millimeter-Wave Radar
High-resolution, short-range sensors that can be applied in optically challenging environments (e.g., in the presence of clouds, fog, and/or dark smog) are in high demand. Ultrawideband (UWB) millimeter-wave radars are one of the most promising devices for the above-mentioned applications. For target recognition using sensors, it is necessary to convert observational data into full 3-D images with both time efficiency and high accuracy. For such conversion algorithm, we have already proposed the range points migration (RPM) method. However, in the existence of multiple separated objects, this method suffers from inaccuracy and high computational cost due to dealing with many observed RPs. To address this issue, this letter introduces Doppler-based RPs clustering into the RPM method. The results from numerical simulations, assuming 140-GHz band millimeter radars, show that the addition of Doppler velocity into the RPM method results in more accurate 3-D images with reducing computational costs
Transport Properties of Steam Curing Concrete Using Mineral Admixtures
Steam curing has been used widely in the precast concrete industry. However, investigations on steam curing concrete focused mainly on their strength development. Research on durability of steam curing concrete, particularly on mixes using mineral admixtures, is somewhat limited.
In this study, transport properties and mechanical properties of concretes using mineral admixtures under different steam curing conditions were measured. Normal Portland cement, high early strength Portland cement, ground granulated blast-furnace slag and fly ash were used. Steam curing conditions were varied by changing the preliminary curing time, temperature drop rate and curing method after steam curing. Transport properties, such as oxygen gas diffusion coefficient and water diffusion coefficient were measured. Moreover, mechanical properties, such as compressive strength, static elastic modulus and dynamic elastic modulus were measured.
From the experimental result, the degree of the influence that the differences in steam curing conditions give to transport properties varies according to the types of binder. It was confirmed that transport properties might decrease remarkably in comparison with the case of a standard steam curing condition
Coupled channel approach to strangeness S = -2 baryon-bayron interactions in Lattice QCD
The baryon-baryon interactions with strangeness S = -2 with the flavor SU(3)
breaking are calculated for the first time by using the HAL QCD method extended
to coupled channel system in lattice QCD. The potential matrices are extracted
from the Nambu-Bethe-Salpeter wave functions obtained by the 2+1 flavor gauge
configurations of CP-PACS/JLQCD Collaborations with a physical volume of 1.93
fm cubed and with m_pi/m_K = 0.96, 0.90, 0.86. The spatial structure and the
quark mass dependence of the potential matrix in the baryon basis and in the
SU(3) basis are investigated.Comment: 17 pages, 15 figure
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