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1. chinaXiv:201711.00041 [pdf]

Circulating Fluidized Bed Gasification of Low Rank Coal: Influence of O-2/C Molar Ratio on Gasification Performance and Sulphur Transformation

Zhang, H. X.,; Zhang, Y. K., ; Zhu, Z. P. ; Lu, Q. G.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

To promote the utilization efficiency of coal resources, and to assist with the control of sulphur during gasification and/or downstream processes, it is essential to gain basic knowledge of sulphur transformation associated with gasification performance. In this research we investigated the influence of O-2/C molar ratio both on gasification performance and sulphur transformation of a low rank coal, and the sulphur transformation mechanism was also discussed. Experiments were performed in a circulating fluidized bed gasifier with O-2/C molar ratio ranging from 0.39 to 0.78 mol/mol. The results showed that increasing the O-2/C molar ratio from 0.39 to 0.78 mol/mol can increase carbon conversion from 57.65% to 91.92%, and increase sulphur release ratio from 29.66% to 63.11%. The increase of O-2/C molar ratio favors the formation of H2S, and also favors the retained sulphur transforming to more stable forms. Due to the reducing conditions of coal gasification, H2S is the main form of the released sulphur, which could be formed by decomposition of pyrite and by secondary reactions. Bottom char shows lower sulphur content than fly ash, and mainly exist as sulphates. X-ray photoelectron spectroscopy (XPS) measurements also show that the intensity of pyrite declines and the intensity of sulphates increases for fly ash and bottom char, and the change is more obvious for bottom char. During CFB gasification process, bigger char particles circulate in the system and have longer residence time for further reaction, which favors the release of sulphur species and can enhance the retained sulphur transforming to more stable forms.

submitted time 2017-11-02 From cooperative journals:《热科学学报》 Hits785Downloads412 Comment 0

2. chinaXiv:201705.00597 [pdf]

LaFe11.6Si1.4Hy/Sn magnetocaloric composites by hot pressing

Zhang, H [Zhang, Heng][ 1,2,3 ]; Liu, J [Liu, Jian][ 1,2 ]; Zhang, MX [Zhang, Mingxiao][ 1,2 ]; Shao, YY [Shao, Yanyan][ 1,2 ]; Li, Y [Li, Yang][ 1,2,3 ]; Yan, A [Yan, Aru][ 1,2 ]
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

We report on the microstructure, mechanical properties, magnetocaloric effect and thermal transfer performance of LaFe11.6Si1.4Hy/Sn composites prepared by hot pressing. The liquid Sn forms a homogenous continuous matrix but does not react with LaFe11.6Si1.4Hy grains during compacting. By controlling pressing temperature, a set of composites combined high entropy change values of 10–13 J/kg K at 2 T with high thermal conductivity of about 7 W/mK has been obtained in a magnetostructural transition range of 1–17 °C.

submitted time 2017-05-02 Hits9383Downloads756 Comment 0

3. chinaXiv:201705.00570 [pdf]

Low lattice thermal conductivity of stanene

Peng, B [Peng, Bo][ 1 ]; Zhang, H [Zhang, Hao][ 1 ]; Shao, HZ [Shao, Hezhu][ 2 ]; Xu, YC [Xu, Yuchen][ 1 ]; Zhang, XC [Zhang, Xiangchao][ 1 ]; Zhu, HY [Zhu, Heyuan][ 1 ]
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

A fundamental understanding of phonon transport in stanene is crucial to predict the thermal performance in potential stanene-based devices. By combining rst-principle calculation and phonon Boltzmann transport equation, we obtain the lattice thermal conductivity of stanene. A much lower thermal conductivity (11.6W/mK) is observed in stanene, which indicates higher thermoelectric e ciency over other 2D materials. The contributions of acoustic and optical phonons to the lattice thermal conductivity are evaluated. Detailed analysis of phase space for three-phonon processes shows that phonon scattering channels LA + LA/TA/ZA ? TA/ZA are restricted, leading to the dominant contributions of high-group-velocity LA phonons to the thermal conductivity. The size dependence of thermal conductivity is investigated as well for the purpose of the design of thermoelectric nanostructures.

submitted time 2017-05-02 Hits698Downloads451 Comment 0

4. chinaXiv:201705.00567 [pdf]

Alloyed nanoparticle-embedded alumina nanocermet film: A new attempt to improve the thermotolerance

Tu, CJ [Tu, C. J.][ 1,2 ]; Gao, JH [Gao, J. H.][ 2 ]; Hui, S [Hui, S.][ 1,2 ]; Lou, D [Lou, D.][ 1 ]; Zhang, HL [Zhang, H. L.][ 2 ]; Liang, LY [Liang, L. Y.][ 2 ]; Jin, AP [Jin, A. P.][ 3 ]; Zou, YS [Zou, Y. S.][ 1 ]; Cao, HT [Cao, H. T.][ 2 ]
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

This paper focuses on the enhancement of thermal stability of Ag-Al2O3 nanocermet films by means of alloying of Ag nanoparticles with Al element. The optical analysis demonstrated the AgAl embedded Al2 O3 cermet films (namely, AgAl-Al2O3) possess excellent thermal tolerance even at 500?C for 260h under nitrogen ambient. The evolution of microstructural and chemical properties of Al2O3/AgAl-Al2O3/Al2O3 stack layers during the annealing process was comprehensively investigated, in order to grasp the thermal stability mechanism. It is believed that the enhanced thermal stability was ascribed to the formation of fresh alumina as capping layer riveted on the Ag nanoparticles surfaces, which acted as the pinning points to prevent silver element from migrating so as to maintain the expected optical properties.

submitted time 2017-05-02 Hits661Downloads391 Comment 0

5. chinaXiv:201705.00537 [pdf]

First-Principles Prediction of Ultralow Lattice Thermal Conductivity of Dumbbell Silicene: A Comparison with Low-Buckled Silicene

Peng, B [Peng, Bo][ 1,2 ]; Zhang, H [Zhang, Hao][ 1,2 ]; Shao, HZ [Shao, Hezhu][ 3 ]; Xu, YF [Xu, Yuanfeng][ 1,2 ]; Zhang, RJ [Zhang, Rongjun][ 1,2 ]; Lu, HL [Lu, Hongliang][ 4 ]; Zhang, DW [Zhang, David Wei][ 4 ]; Zhu, HY [Zhu, Heyuan][ 1,2 ]
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

The dumbbell structure of two-dimensional group IV material offers alternatives to grow thin films for diverse applications. Thermal properties are important for these applications. We obtain the lattice thermal conductivity of low-buckled (LB) and dumbbell (DB) silicene by using first-principles calculations and the Boltzmann transport equation for phonons. For LB silicene, the calculated lattice thermal conductivity with naturally occurring isotope concentrations is 27.72 W/mK. For DB silicene, the calculated value is 2.86 W/mK. The thermal conductivity for DB silicene is much lower than LB silicene due to stronger phonon scattering. Our results will induce further theoretical and experimental investigations on the thermoelectric (TE) properties of DB silicene. The size-dependent thermal conductivity in both LB and DB silicene is investigated as well for designing TE devices. This work sheds light on the manipulation of phonon transport in two-dimensional group IV materials by dumbbell structure formed from the addition of adatoms.

submitted time 2017-05-02 Hits2346Downloads383 Comment 0

6. chinaXiv:201705.00280 [pdf]

Towards intrinsic phonon transport in single-layer MoS2

Peng, B [Peng, Bo][ 1,2 ]; Zhang, H [Zhang, Hao][ 1,2 ]; Shao, HZ [Shao, Hezhu][ 3 ]; Xu, YF [Xu, Yuanfeng][ 1,2 ]; Zhang, XC [Zhang, Xiangchao][ 1,2 ]; Zhu, HY [Zhu, Heyuan][ 1,2 ]

The intrinsic lattice thermal conductivity of MoS2 is an important aspect in the design of MoS2-based nanoelectronic devices. We investigate the lattice dynamics properties of MoS2 by first-principle calculations. The intrinsic thermal conductivity of sin

submitted time 2017-05-02 Hits689Downloads363 Comment 0

7. chinaXiv:201612.00370 [pdf]

Probing R-parity Violating Interactions from Top Quark Polarization at LHC

Li,P; Lu,G; Yang,JM; Zhang,H
Subjects:

In minimal supersymmetric standard model the R-parity violating interactions can induce anomalous top pair productions at the LHC through the t-channel process d_R \bar d_R -> t_L \bar t_L by exchanging a slepton or u-channel process d_R \bar d_R -> t_R \

submitted time 2016-12-28 Hits1351Downloads704 Comment 0

8. chinaXiv:201612.00369 [pdf]

Production of h t anti-t and h t anti-T in littlest Higgs model with T-parity

Wang,L; Wang,W; Yang,JM; Zhang,H
Subjects:

In the littlest Higgs model with T-parity, which predicts a pair of T-even and T-odd partners for the top quark, the top quark interactions are altered with respect to the Standard Model predictions and deviation will manifest in various top quark process

submitted time 2016-12-28 Hits1096Downloads598 Comment 0

9. chinaXiv:201612.00368 [pdf]

Virtual Effects of Split SUSY in Higgs Productions at Linear Colliders

Wang,F; Wang,W; Xu,F; Yang,JM; Zhang,H
Subjects:

In split supersymmetry the gauginos and higgsinos are the only supersymmetric particles possibly accessible at foreseeable colliders like the CERN Large Hadron Collider (LHC) and the International Linear Collider (ILC). In order to account for the cosmic

submitted time 2016-12-28 Hits1271Downloads686 Comment 0

10. chinaXiv:201612.00366 [pdf]

Top-quark FCNC Productions at CERN LHC in Topcolor-assisted Technicolor Model

Cao,J; Liu,G; Yang,JM; Zhang,H
Subjects:

We evaluate the top-quark FCNC productions induced by the topcolor assisted technicolor (TC2) model at the LHC. These productions proceed respectively through the parton-level processes g g -> t c_bar, c g->t, c g -> t g, c g -> t Z and c g -> t \gamma. W

submitted time 2016-12-28 Hits1112Downloads632 Comment 0

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