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| 2. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Li, Yongxi, et al.
(författare)
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A fused-ring based electron acceptor for efficient non-fullerene polymer solar cells with small HOMO offset
- 2016
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Ingår i: NANO ENERGY. - : ELSEVIER SCIENCE BV. - 2211-2855. ; 27, s. 430-438
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Tidskriftsartikel (refereegranskat)abstract
- A non-fullerene electron acceptor bearing a novel backbone with fused 10-heterocyclic ring (in-dacenodithiopheno-indacenodiselenophene), denoted by IDTIDSe-IC is developed for fullerene free polymer solar cells. IDTIDSe-IC exhibits a low band gap (E-g=1.52 eV) and strong absorption in the 600850 nm region. Combining with a large band gap polymer J51 (E-g=1.91 eV) as donor, broad absorption coverage from 300 nm to 800 nm is obtained due to complementary absorption of J51 and IDTIDSe-IC, which enables a high PCE of 8.02% with a V-oc of 0.91 V, a J(SC) of 15.16 mA/cm(2) and a FF of 58.0% in the corresponding PSCs. Moreover, the EQE of 50-65% is achieved in the absorption range of IDTIDSe-IC with only about 0.1 eV HOMO difference between J51 and IDTIDSe-IC. (C) 2016 Elsevier Ltd. All rights reserved.
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| 4. |
- Guo, Junji, et al.
(författare)
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Mechanistic Insights into the Coloration, Evolution, and Degradation of NiOx Electrochromic Anodes
- 2018
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Ingår i: Inorganic Chemistry. - : AMER CHEMICAL SOC. - 0020-1669 .- 1520-510X. ; 57:15, s. 8874-8880
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Tidskriftsartikel (refereegranskat)abstract
- NiOx is recognized as the leading candidate for smart window anodes that can dynamically modulate optical absorption, thereby achieving energy efficiency in construction buildings. However, the electrochromic mechanism in NiOx is not yet clear, and the ionic species involved are sometimes ambiguous, particularly in aprotic electrolytes. We demonstrate herein that the "net coloration effect" originates from newly generated high-valence Ni3+/Ni4+ ions during anion-dependent anodization, and the Li+ intercalation/deintercalation only plays a role in modulating the oxidation state of Ni. Unambiguous evidences proving the occurrence of anodization reaction were obtained by both chronoamperometry and cyclic voltammetry. Benefiting from the irreversible polarization of Ni2+ to Ni3+/Ni4+, the quantity of voltammetric charge increases by similar to 38% under the same test conditions, enhancing the corresponding electrochromic modulation by similar to 8%. Strong linkages between the coloration, evolution, and degradation observed in this work provide in-depth insights into the electrocatalytic and electrochromic mechanisms.
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| 5. |
- Jin, Zhi Jiang, et al.
(författare)
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Computational fluid dynamics analysis on orifice structure inside valve core of pilot-control angle globe valve
- 2018
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science. - : SAGE Publications. - 0954-4062 .- 2041-2983. ; 232:13, s. 2419-2429
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Tidskriftsartikel (refereegranskat)abstract
- A novel pilot-control angle globe valve is proposed, and it has an obvious advantage of energy conservation during its opening and closing process. In pilot-control angle globe valve, the opening and closing forces are related to the orifice located inside the valve core. In this paper, the effects of orifice diameter are thoroughly studied under different working conditions such as valve core displacements and inlet velocities. To begin with, the numerical model is validated by comparing similar angle valves, and then the flow and loss coefficients under different orifice diameters are discussed. It is found that the effects of orifice diameter on force acting on valve core depend on valve core displacement and inlet velocity. Thus different valve core displacements and inlet velocities combined with different orifice diameters are further studied. It is also found that when the orifice diameter is larger than 12 mm, pilot-control angle globe valve cannot be used under small inlet velocity or large valve core displacement. In addition, formulas to calculate forces on valve core are proposed for further orifice design. This work can be referred in process industries especially in a piping system with orifice plates or globe valves.
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| 6. |
- Jin, Zhi-jiang, et al.
(författare)
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Pressure Drop Analysis of Pilot-Control Globe Valve With Different Structural Parameters
- 2017
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Ingår i: Journal of Fluids Engineering. - : ASME International. - 0098-2202 .- 1528-901X. ; 139:9
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Tidskriftsartikel (refereegranskat)abstract
- Pilot-control globe valve (PCGV) can use the pressure drop caused by fluid flowing through the orifice located at valve core bottom to open or close the main valve using a small pilot valve. In this paper, computational fluid dynamics (CFD) method is adopted to analyze the pressure drop before and after valve core of PCGV and minor loss of orifice under different structural parameters and inlet velocities, and the simulation results show a good agreement with the experimental results. It turns out that the valve diameters, orifice diameters, and pilot pipe diameters have great influences on the pressure drop and the loss coefficient. Moreover, an expression is proposed which can be used to calculate minor loss coefficient, then to estimate the pressure drop and driving force of a PCGV within limited conditions. This paper can be referenced as guidance for deciding the dimension of structural parameters and spring stiffness during design process of a PCGV.
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| 7. |
- Qian, Jin yuan, et al.
(författare)
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Flow rate analysis of compressible superheated steam through pressure reducing valves
- 2017
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Ingår i: Energy. - : Elsevier BV. - 0360-5442. ; 135, s. 650-658
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Tidskriftsartikel (refereegranskat)abstract
- Steam flow is the main form for energy transfer in power plants, process industries, etc. The flow rate of the steam relates to the energy transfer amount directly. Pressure reducing valves are used for flow rate control of the compressible superheated steam in these piping systems. In this paper, a pressure reducing valve with a novel valve core is proposed. In order to analyze the internal flow characteristics of the compressible superheated steam and the flow rate adjustment performance of the proposed pressure reducing valve, a numerical model of DN80 pressure reducing valve is established. Then, the flow characteristics inside are studied numerically. Meanwhile, the flow rate adjustment performance is also carried out experimentally. Compared with the numerical and experimental results, it shows an agreement and both of them are similar to linear flow rate. Furthermore, a fitting equation for the flow rate prediction is carried out for the engineering applications under different working conditions.
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| 8. |
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| 9. |
- Chen, Fu qiang, et al.
(författare)
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Pressure analysis on two-step high pressure reducing system for hydrogen fuel cell electric vehicle
- 2017
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Ingår i: International Journal of Hydrogen Energy. - : Elsevier BV. - 0360-3199. ; 42:16, s. 11541-11552
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogen fuel cell electric vehicle (FCEV) can achieve zero exhaust emission and zero pollution. In order to make FCEV reach a farther travel distance, greater demands are put on its pressure reducing system. In this paper, a two-step high pressure reducing system for FCEV is proposed. The system is made up of two parts, a new high multi-stage pressure reducing valve (HMSPRV) and a multi-stage muffler. As a new system, its feasibility has to be verified. Since the valve opening condition has a great effect on hydrogen flow, pressure reduction and energy consumption, different valve opening conditions are taken as the research point. The flow field analysis of the new HMSPRV is conducted on three aspects: pressure field, velocity field and energy consumption. It can be found that both the pressure reducing and velocity increasing gradients mainly reflect at those throttling components for all valve openings. For energy consumption, in the comprehensive study of flow vortexes and turbulent dissipation rate, it can be found that the larger of the valve opening, the larger of energy consumption. Then, a thermo-fluid-solid coupling analysis is conducted on the new HMSPRV, and it is concluded that the new system meets strength requirement. Furthermore, as the second step of the high pressure reducing system, the flow and pressure fields of multi-stage muffler are investigated. The five-stage muffler is exactly designed to complete the whole pressure reducing process. This study can provide technological support for achieving pressure regulation in the hydrogen transport system of FCEV when facing complex conditions, and it can also benefit the further research work on energy saving and multi-stage flow of pressure reducing devices.
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| 10. |
- Chen, Fu qiang, et al.
(författare)
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Thermo-mechanical stress and fatigue damage analysis on multi-stage high pressure reducing valve
- 2017
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Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549. ; 110, s. 753-767
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Tidskriftsartikel (refereegranskat)abstract
- A multi-stage high pressure reducing valve (MSHPRV) is proposed. It can achieve a multi-stage pressure reducing way. Valve failure mainly occurs under high pressure and high temperature conditions, thus it is necessary to investigate the strength of MSHPRV under those complex conditions. In this paper, the mathematical model of MSHPRV is established and Computational Fluid Dynamics (CFD) method is employed to simulate its flow fields and thermo-mechanical stress. Next, the stress of MSHPRV under different opening time and the fatigue damage of MSHPRV under different valve openings are studied. Finally, two changes are provided on geometry of MSHPRV and the geometrical factors are optimized. The results show that, the radial direction from inner wall to outer wall is the main heat transfer direction for valve body. At opening time 50 s, the working condition of MSHPRV is dangerous condition. Meanwhile, the maximum value of thermal stress is 487 MPa, which is located at the upper end face of valve chamber region B3. There is a lag effect of stress distribution with respect to temperature distribution. The combined stress of valve body is composed of thermal stress and mechanical stress, in which thermal stress holds the dominant position. Moreover, with the increasing of valve opening, the fatigue damage of valve body increases correspondingly. It can be concluded that MSHPRV can cope with complex conditions like high pressure and high temperature. In the optimization design of MSHPRV, it can be found that the best strength of MSHPRV is achieved with such geometrical factors as angle 15, diameter 4 mm and 2 stage plates. Besides, radian design as the improved structure is recommended. This work can benefit the further research work on the regulation performance and safe operation of high pressure reducing valve.
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