The JUNO experiment locates in Jinji town, Kaiping city, Jiangmen city, Guangdong province. The geographic location is east longitude 112 • 31'05' and North latitude 22 • 07'05'. The experimental site is 43 km to the southwest of the Kaiping city, a county-level city in the prefecture-level city Jiangmen in Guangdong province. There are five big cities, Guangzhou, Hong Kong, Macau, Shenzhen, and Zhuhai, all in ∼200 km drive distance, as shown in figure 3.

By using ab initio calculations, we predict that a vertical electric field is able to open a band gap in semimetallic single-layer buckled silicene and germanene. The sizes of the band gap in both silicene and germanene increase linearly with the electric field strength. Ab initio quantum transport simulation of a dual-gated silicene field effect transistor confirms that the vertical electric field opens a transport gap, and a significant switching effect by an applied gate voltage is also observed. Therefore, biased single-layer silicene and germanene can work effectively at room temperature as field effect transistors.

Identified charged-particle spectra of π ± , K ± , p, and p at midrapidity (|y| < 0.1) measured by the dE/dx method in the STAR (solenoidal tracker at the BNL Relativistic Heavy Ion Collider) time projection chamber are reported for pp and d + Au collisions at √ s NN = 200 GeV and for Au + Au collisions at 62.4, 130, and 200 GeV. Average transverse momenta, total particle production, particle yield ratios, strangeness, and baryon production rates are investigated as a function of the collision system and centrality. The transverse momentum spectra are found to be flatter for heavy particles than for light particles in all collision systems; the effect is more prominent for more central collisions. The extracted average transverse momentum of each particle species follows a trend determined by the total charged-particle multiplicity density. The Bjorken energy density estimate is at least several GeV/fm 3 for a formation time less than 1 fm/c. A significantly larger net-baryon density and a stronger increase of the net-baryon density with centrality are found in Au + Au collisions at 62.4 GeV than at the two higher energies. Antibaryon production relative to total particle multiplicity is found to be constant over centrality, but increases with the collision energy. Strangeness production relative to total particle multiplicity is similar at the three measured RHIC energies. Relative strangeness production increases quickly 034909-2 SYSTEMATIC MEASUREMENTS OF IDENTIFIED . . . (2009) with centrality in peripheral Au + Au collisions, to a value about 50% above the pp value, and remains rather constant in more central collisions. Bulk freeze-out properties are extracted from thermal equilibrium model and hydrodynamics-motivated blast-wave model fits to the data. Resonance decays are found to have little effect on the extracted kinetic freeze-out parameters because of the transverse momentum range of our measurements. The extracted chemical freeze-out temperature is constant, independent of collision system or centrality; its value is close to the predicted phase-transition temperature, suggesting that chemical freeze-out happens in the vicinity of hadronization and the chemical freeze-out temperature is universal despite the vastly different initial conditions in the collision systems. The extracted kinetic freeze-out temperature, while similar to the chemical freeze-out temperature in pp, d + Au, and peripheral Au + Au collisions, drops significantly with centrality in Au + Au collisions, whereas the extracted transverse radial flow velocity increases rapidly with centrality. There appears to be a prolonged period of particle elastic scatterings from chemical to kinetic freeze-out in central Au + Au collisions. The bulk properties extracted at chemical and kinetic freeze-out are observed to evolve smoothly over the measured energy range, collision systems, and collision centralities. PHYSICAL REVIEW C 79, 034909

We report the WIMP dark matter search results using the first physics-run data of the PandaX-II 500 kg liquid xenon dual-phase time-projection chamber, operating at the China JinPing underground Laboratory. No dark matter candidate is identified above background. In combination with the data set during the commissioning run, with a total exposure of 3.3×10 4 kg-day, the most stringent limit to the spin-independent interaction between the ordinary and WIMP dark matter is set for a range of dark matter mass between 5 and 1000 GeV/c 2 . The best upper limit on the scattering cross section is found 2.5 × 10 −46 cm 2 for the WIMP mass 40 GeV/c 2 at 90% confidence level.Weakly interacting massive particles, WIMPs in short, are a class of hypothetical particles that came into existence shortly after the Big Bang. The WIMPs could naturally explain the astronomical and cosmological evidences of dark matter in the Universe. The weak interactions between WIMPs and ordinary matter could lead to the recoils of atomic nuclei that produce detectable signals in deep-underground direct detection experiments. Over the past decade, the dual-phase xenon time-projection chambers (TPC) emerged as a powerful technology for WIMP searches both in scaling up the target mass, as well as in improving background rejection [1][2][3]. LUX, a dark matter search experiment with a 250 kg liquid xenon target, has recently reported the best limit of 6×10 −46 cm 2 on the WIMP-nucleon scattering cross section [4] The PandaX-II experiment, a half-ton scale dual-phase xenon experiment at the China JinPing underground Laboratory (CJPL), has recently reported the dark matter search results from its commissioning run (Run 8,19.1 live days) with a 5845 kg-day exposure [5]. The data were contaminated with significant 85 Kr background. After a krypton distillation campaign in early 2016, PandaX-II commenced physics data taking in March 2016. In this paper, we report the combined WIMP search results using the data from the first physics run from March 9 to June 30, 2016 (Run 9, 79.6 live days) and Run 8, with a total of 3.3×10 4 kg-day exposure, the largest reported WIMP data set among dual-phase xenon detectors in the world to date.The PandaX-II detector has been described in detail in Ref. [5]. The liquid xenon target consists of a cylindrical TPC with dodecagonal cross section (opposite-side distance 646 mm), confined by the polytetrafluoroethylene (PTFE) reflective wall, and a vertical drift distance of 600 mm defined by the cathode mesh and gate grid located at the bottom and top. For each physical event, the prompt scintillation photons (S1) and the delayed electroluminescence photons (S2) from the ionized electrons are collected by two arrays of 55 Hamamatsu R11410-arXiv:1607.07400v3 [hep-ex] Hamamatsu R8520-406 1-inch PMTs serving as an active veto. The γ background, which produces electron recoil (ER) events, can be distinguished from the dark matter nuclear recoil (NR) using the S2-to-S1 ratio. During the data taking period in Run 9, a few diffe...

Energy storage and conversion remain signifi cantly challenging to the research community. Among the candidates, lithium-ion batteries show great attraction and have been used in a wide range of applications, from small electronic devices, such as mobile phones and notebook computers, to increasing numbers of electric vehicles and large-scale energy storage equipments. [1][2][3][4][5][6] However, the relatively high cost of lithium resources shows the potential problems in terms of the long-term and large-scale applications of lithium-ion batteries. Lithium resources are limited; lithium makes up about 0.0065% of the earth ′ s crust and is unevenly distributed in South America. Thus, development of alternative storage devices is not only desirable but also necessary. Given this background, intense interest in the use of sodium-ion batteries particularly for largescale energy storage has recently been rekindled. Sodium, an element of electrochemical equivalence and proper potential, could be used as a substitute for lithium to meet the demands of rechargeable batteries. Furthermore, the sodium resources are considered to be unlimited and sodium salts widely exist in the sea. Therefore, sodium-ion batteries demonstrate the potential to substitute for lithium-ion batteries in the particular application in large-scale energy storage for renewable solar and wind power as well as smart grid. [ 7 , 8 ] Tremendous attention has been paid to sodium-ion batteries in recent years. Many electrode materials, such as Na x CoO 2 , [ 9 ] NaCrO 2 , [ 10 ] Na 1.0 Li 0.2 Ni 0.25 Mn 0.75 O δ , [ 11 , [ 17 ] hard carbon [ 13 , 18 , 19 ] and TiO 2 [ 20 ] have been investigated for application in sodium-ion batteries. Very recently, we reinvestigated the sodium ion insertion/extraction into/from Na 3 V 2 (PO 4 ) 3 with a NASICON structure. [ 21 ] The NASICON structure features a highly covalent three-dimensional framework that generates large interstitial spaces through which sodium ions may diffuse. [22][23][24] Our previous study was the fi rst to demonstrate that carbon coating can signifi cantly improve its sodium storage performance. [ 21 ] Carbon-coated Na 3 V 2 (PO 4 ) 3 electrodes show two fl at plateaus at 3.4 V and 1.6 V vs. Na + / Na, respectively. The voltage plateau located at 3.4 V is relatively higher than that of other cathode materials for sodium-ion batteries in recent reports. [9][10][11][12][13][14][15] However, the coulombic efficiency of the Na 3 V 2 (PO 4 ) 3 electrode in a half-cell is not as high as 99.5%, and does not even increase after the fi rst cycle, [ 21 ] likely because of the NaClO 4 /PC electrolyte used. Moreover, the storage capacity could also be enhanced by decreasing the carbon content of the composite and using optimized electrolyte system. In this contribution, Na 3 V 2 (PO 4 ) 3 /C nanocomposites with different carbon contents were prepared by a one-step solid state reaction and evaluated in different electrolyte systems. It was found that the sodium storage performance in terms of capacity...