Two particle correlations: a probe of the LHC QCD medium

The properties of $\gamma$--jet pairs emitted in heavy-ion collisions provide an accurate mean to perform a tomographic measurement of the medium created in the collision through the study of the medium modified jet properties. The idea is to measure the distribution of hadrons emitted on the opposite side of the %oppositely by tagging the direct photon. The feasibility of such measurements is studied by applying the approach on the simulation data, we have demonstrated that this method allows us to measure, with a good approximation, both the jet fragmentation and the back-to-back azimuthal alignment of the direct photon and the jet. Comparing these two observables measured in pp collisions with the ones measured in AA collisions reveals the modifications induced by the medium on the jet structure and consequently allows us to infer the medium properties. In this contribution, we discuss a first attempt of such measurements applied to real proton-proton data from the ALICE experiment.Comment: 4 pages, 4 figures, Proceedings for Hot Quark 2010 Conferenc

Experimental investigation of heat transfer effectiveness on finned-tube thermoacoustic heat exchanger

Heat exchangers are some of the most important parts in thermoacoustic devices. In an oscillatory flow condition, the flow and temperature fields around the heat exchangers can be quite complex and it may significantly affect their heat transfer behaviour. As a result, one cannot directly apply the heat transfer correlations for a steady flow to the design of heat exchangers operating in oscillatory flow conditions. However, the fundamental knowledge of heat transfer in oscillatory flow is still not well established. The aim of the current work is to establish the heat transfer correlation for a few selected finned-tube heat exchangers, by measuring the heat transfer from the heat exchangers to the oscillatory flow in a range of operating conditions. Among the main parameters considered are fin spacing, fin length, thermal penetration depth, and gas displacement amplitude, and their effect on the thermal performance of heat exchangers. The results are presented in term of heat transfer effectiveness, which is the ratio of actual heat transfer rate to the maximum possible heat transfer rate. The correlations are proposed between the heat transfer effectiveness and the ratios of the fin length to the displacement amplitude and the fin spacing to the thermal penetration depth. The uncertainties associated with all the measurement data are also considered

P2-type Na2/3Ni1/3Mn2/3O2 Cathode Material with Excellent Rate and Cycling Performance for Sodium-Ion Batteries

P2-type Na2/3Ni1/3Mn2/3O2 is an air-stable cathode material for sodium-ion batteries. However, it suffers irreversible P2-O2 phase transition in 4.2-V plateau and shows poor cycling stability and rate capability within this plateau. To evaluate the practicability of this material in 2.3–4.1 V voltage range, single-crystal micro-sized P2-type Na2/3Ni1/3Mn2/3O2 with high rate capability and cycling stability is synthesized via polyvinylpyrrolidone (PVP)-combustion method. The electrochemical performance is evaluated by galvanostatic charge-discharge tests. The kinetics of Na+ intercalation/deintercalation is studied detailly with potential intermittent titration technique (PITT), galvanostatic intermittent titration technique (GITT) and cyclic voltammetry (CV). The discharge capacity at 0.1 C in 2.3–4.1 V is 87.6 mAh g−1. It can deliver 91.5% capacity at 40 C rate and keep 89% after 650 cycles at 5C. The calculated theoretical energy density of full cell with hard carbon anode is 210 Wh kg−1. The moderate energy density associated with high power density and long cycle life is acceptable for load adjustment of new-energy power, showing the prospect of practical application

Statistical analysis on spatial correlation of ionospheric day-to-day variability by using GPS and Incoherent Scatter Radar observations

In this paper, the spatial correlations of ionospheric day-to-day variability are investigated by statistical analysis on GPS and Incoherent Scatter Radar observations. The meridional correlations show significant (>0.8) correlations in the latitudinal blocks of about 6 degrees size on average. Relative larger correlations of TEC's day-to-day variabilities can be found between magnetic conjugate points, which may be due to the geomagnetic conjugacy of several factors for the ionospheric day-to-day variability. The correlation coefficients between geomagnetic conjugate points have an obvious decrease around the sunrise and sunset time at the upper latitude (60°) and their values are bigger between the winter and summer hemisphere than between the spring and autumn hemisphere. The time delay of sunrise (sunset) between magnetic conjugate points with a high dip latitude is a probable reason. Obvious latitude and local time variations of meridional correlation distance, latitude variations of zonal correlation distance, and altitude and local time variations of vertical correlation distance are detected. Furthermore, there are evident seasonal variations of meridional correlation distance at higher latitudes in the Northern Hemisphere and local time variations of zonal correlation distance at higher latitudes in the Southern Hemisphere. These variations can generally be interpreted by the variations of controlling factors, which may have different spatial scales. The influences of the occurrence of ionospheric storms could not be ignored. Further modeling and data analysis are needed to address this problem. We suggest that our results are useful in the specific modeling/forecasting of ionospheric variability and the constructing of a background covariance matrix in ionospheric data assimilation

Study on inhibitory effect of Spica Prunellae extract on T Lymphoma cell EL-4 tumor

The objective of the study was to investigate the in-vivo anti-tumour activity of Spica prunellae extract, and to preliminarily explore the possible mechanism of in-vivo anti-tumour effect of Spica prunellae extract. Tumour inhibition rate and tumour apoptosis-related protein status were determined using the mice model of transplanted T lymphoma cell EL-4 tumour, and by immunohistochemical method. The results revealed that Spica prunellae extract showed certain tumour inhibitory effect, and compared with the model group. Tumour weight in Spica prunellae high-dose group was highly significantly different (P<0.01). Tumour weight in Spica prunellae medium-dose group was also significantly different (P<0.05) compared with the model group. Spica prunellae high-dose group enabled the high expression of Bcl-2 protein (47.54%) and low expression of Bax protein (13.14%). The study concluded that Spica prunellae extract has certain in vivo anti-tumour effect, which may be achieved through regulation of apoptosis related proteins.Key words: Spica prunellae, EL-4 solid tumour, tumour inhibition, mechanis