The hyperon mean free paths in the relativistic mean field

The $\Lambda$- and $\Xi^-$-hyperon mean free paths in nuclei are firstly calculated in the relativistic mean field (RMF) theory. The real parts of the optical potential are derived from the RMF approach, while the imaginary parts are obtained from those of nucleons with the relations: $U^{\mathrm{IY}}_{\mathrm{S}} = \alpha_{\sigma \mathrm{Y}}\cdot U_{\mathrm{S}}^{\mathrm{IN}}$ and $U^{\mathrm{IY}}_{\mathrm{V}} = \alpha_{\omega \mathrm{Y}}\cdot U_{\mathrm{V}}^{\mathrm{IN}}$ . With the assumption, the depth of the imaginary potential for $\Xi^-$ is $W_{\Xi}\simeq-$ 3.5 MeV, and for $\Lambda$ is $W_{\Lambda}\simeq-$ 7 MeV at low incident energy. We find that, the hyperon mean free path decreases with the increase of the hyperon incident energies, from 200 MeV to 800 MeV; and in the interior of the nuclei, the mean free path is about $2\sim 3$ fm for $\Lambda$, and about $4\sim 8$ fm for $\Xi^-$, depending on the hyperon incident energy.Comment: 5 figures, 6 page

Effect of Wine Closures on the Aroma Properties of Chardonnay Wines after Four Years of Storage

The effects of wine closures on the sensory properties and aroma profiles of fresh Chardonnay wines wereevaluated after four years of bottle storage. Natural cork closure, technical cork closure, Nomacorc light,Nomacorc classic and Nomacorc premium were investigated. Among these wines sealing with differentclosures, the physicochemical parameters of the wine samples showed no significant differences, exceptthat of the free and total sulphur dioxide. Nomacorc light with the highest OTR (oxygen transition rate)had the least residual free sulphur dioxide. Most of volatiles were generally stable, and seven compounds(acetoin, 1-butanol, 2-phenylethanol, 1-pentanol, (Z)-3-hexen-1-ol, 2-nonanol and ethyl decanoate) weresignificantly affected by the wine closures. The sensory analysis revealed that cork closures preserved morefruity/flowery characters of the fresh wines after four years’ storage, as well as cork-tainted off-flavour.Two synthetic closures (Nomacorc light, Nomacorc classic) imparted some grilled attributes to the wines.Nomacorc premium highly reserved the fruity/flowery flavour without cork contamination or oxidisedtoasted characters

Single-Atom Reversible Lithiophilic Sites toward Stable Lithium Anodes

Lithiophilic sites with high binding energy to Li have shown the capability to guide uniform Li deposition, however, the irreversible reaction between Li and lithiophilic sites causes a loss of lithiophilicity. Herein, the concept of using reversible lithiophilic sites, such as single-atoms (SAs) doped graphene, as a host, is systematically inspected in the context of Li metal battery (LMB) performance. Here, it is proposed that the binding energy to Li atoms should be within a certain threshold range, i.e., strong enough to inhibit Li dendrite growth and weak enough to avoid host structure collapse. Six kinds of SAs are utilized; doped 3D graphene, nitrogen-doped 3D graphene, and pure 3D graphene, whose performance in LMBs are compared with each other. It is discovered that the SA-Mn doped 3D graphene (SAMn@NG) has the most reversible lithiophilic site, in which adsorption strength with Li is suitable to guide uniform deposition and keep the structure stable. During Li plating/stripping, the changes of the atomic structures in SAMn@NG, such as change of bond length and bond angle around Mn atoms are much smaller than those on SAZr@NG, although its binding energy is higher, enabling a much-improved battery performance in SAMn@NG. This work provides a new insight to design lithiophilic sites in LMBs

Multistage Random Growing Small-World Networks with Power-law degree Distribution

In this paper, a simply rule that generates scale-free networks with very large clustering coefficient and very small average distance is presented. These networks are called {\bf Multistage Random Growing Networks}(MRGN) as the adding process of a new node to the network is composed of two stages. The analytic results of power-law exponent $\gamma=3$ and clustering coefficient $C=0.81$ are obtained, which agree with the simulation results approximately. In addition, the average distance of the networks increases logarithmical with the number of the network vertices is proved analytically. Since many real-life networks are both scale-free and small-world networks, MRGN may perform well in mimicking reality.Comment: 3 figures, 4 page

The two emission states of PSR B1534+12

We have observed PSR~B1534+12 (J1537+1155), a pulsar with a neutron star companion, using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). We found that this pulsar shows two distinct emission states: a weak state with a wide pulse profile and a burst state with a narrow pulse profile. The weak state is always present. We cannot, with our current data, determine whether the pulse energy of the weak state follows a normal or a log-normal distribution. The burst state energy distribution follows a power-law. The amplitude of the single pulse emission in the burst state varies significantly; the peak flux intensity of the brightest pulse is 334 times stronger than that of the average pulse. We also examined the timing precision achievable using only bright pulses, which showed no demonstrable improvement because of pulse jitter and therefore quantified the jitter noise level for this pulsar.Comment: 6 pages, 6 figures, accepted for publication in The Astrophysical Journal Letter

Counter-current chromatography for the separation of terpenoids: A comprehensive review with respect to the solvent systems employed

Copyright @ 2014 The Authors.This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.Natural products extracts are commonly highly complex mixtures of active compounds and consequently their purification becomes a particularly challenging task. The development of a purification protocol to extract a single active component from the many hundreds that are often present in the mixture is something that can take months or even years to achieve, thus it is important for the natural product chemist to have, at their disposal, a broad range of diverse purification techniques. Counter-current chromatography (CCC) is one such separation technique utilising two immiscible phases, one as the stationary phase (retained in a spinning coil by centrifugal forces) and the second as the mobile phase. The method benefits from a number of advantages when compared with the more traditional liquid-solid separation methods, such as no irreversible adsorption, total recovery of the injected sample, minimal tailing of peaks, low risk of sample denaturation, the ability to accept particulates, and a low solvent consumption. The selection of an appropriate two-phase solvent system is critical to the running of CCC since this is both the mobile and the stationary phase of the system. However, this is also by far the most time consuming aspect of the technique and the one that most inhibits its general take-up. In recent years, numerous natural product purifications have been published using CCC from almost every country across the globe. Many of these papers are devoted to terpenoids-one of the most diverse groups. Naturally occurring terpenoids provide opportunities to discover new drugs but many of them are available at very low levels in nature and a huge number of them still remain unexplored. The collective knowledge on performing successful CCC separations of terpenoids has been gathered and reviewed by the authors, in order to create a comprehensive document that will be of great assistance in performing future purifications. © 2014 The Author(s)

Pulse Jitter and Single-pulse Variability in Millisecond Pulsars

Understanding the jitter noise resulting from single-pulse phase and shape variations is important for the detection of gravitational waves using pulsar timing array. We presented measurements of jitter noise and single-pulse variability of 12 millisecond pulsars that are part of the International Pulsar Timing Array sample using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). We found that the levels of jitter noise can vary dramatically among pulsars. A moderate correlation with a correlation coefficient of 0.57 between jitter noise and pulse width is detected. To mitigate jitter noise, we performed matrix template matching using all four Stokes parameters. Our results revealed a reduction in jitter noise ranging from 6.7\% to 39.6\%. By performing longitude-resolved fluctuation spectrum analysis, we identified periodic intensity modulations in 10 pulsars. In PSR J0030+0451, we detected single-pulses with energies more than 10 times the average pulse energy, suggesting the presence of giant pulses. We also observed a periodic mode-changing phenomenon in PSR J0030+0451. We examined the achievable timing precision by selecting a sub-set of pulses with a specific range of peak intensity, but no significant improvement in timing precision is achievable.Comment: 14 pages, 9 figures, Accepted for publication in Ap

Scalar ground-state observables in the random phase approximation

We calculate the ground-state expectation value of scalar observables in the matrix formulation of the random phase approximation (RPA). Our expression, derived using the quasiboson approximation, is a straightforward generalization of the RPA correlation energy. We test the reliability of our expression by comparing against full diagonalization in 0 h-bar omega shell-model spaces. In general the RPA values are an improvement over mean-field (Hartree-Fock) results, but are not always consistent with shell-model results. We also consider exact symmetries broken in the mean-field state and whether or not they are restored in RPA.Comment: 7 pages, 3 figure

Influence of a Conductive Material and Different Anaerobic Inocula on Biochemical Methane Potential of Substrates from Alcoholic Beverage Production

The impact of a conductive material as powdered activated carbon (PAC) on the biochemical methane potential of whisky pot ale (PA) and brewery spent yeast (SY) was investigated. The test was carried out with three different types of anaerobic inocula: manure inoculum (MI), sewage sludge (SS) and granular sludge (GR). Brewery spent yeast produced partial (in sewage and granular sludge) and total (in manure inoculum) methanogenesis inhibition due to the toxicity of some of its constituents (hops extract). The inhibition was overcome by the supplementation of PAC, that improved significantly the anaerobic digestion process for SY, allowing to reach biochemical methane potential values between 657-699 L CH4 kg-1 VS and it reduced redox potential from 369 to 398 mV. The activated carbon did not improve the methane yields from whisky PA since microorganisms did not have difficulties to process this substrate; in fact, the redox potential slightly increased from 355 to 330 mV