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| 2. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Meng, Pingping, et al.
(författare)
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Efficient removal of perfluorooctane sulfonate from aqueous film-forming foam solution by aeration-foam collection
- 2018
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 203, s. 263-270
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Tidskriftsartikel (refereegranskat)abstract
- Aqueous film-forming foams (AFFFs) used in fire-fighting are one of the main contamination sources of perfluorooctane sulfonate (PFOS) to the subterranean environment, requiring high costs for remediation. In this study, a method that combined aeration and foam collection was presented to remove PFOS from a commercially available AFFF solution. The method utilized the strong surfactant properties of PFOS that cause it to be highly enriched at air-water interfaces. With an aeration flow rate of 75 mL/min, PFOS removal percent reached 96% after 2 h, and the PFOS concentration in the collected foam was up to 6.5 mmol/L, beneficial for PFOS recovery and reuse. Increasing the aeration flow rate, ionic strength and concentration of co-existing surfactant, as well as decreasing the initial PFOS concentration, increased the removal percents of PFOS by increasing the foam volume, but reduced the enrichment of PFOS in the foams. With the assistance of a co-existing hydrocarbon surfactant, PFOS removal percent was above 99.9% after aeration-foam collection for 2 h and the enrichment factor exceeded 8400. Aeration-foam collection was less effective for short-chain perfluoroalkyl substances due to their relatively lower surface activity. Aeration-foam collection was found to be effective for the removal of high concentrations of PFOS from AFFF-contaminated wastewater, and the concentrated PFOS in the collected foam can be reused.
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| 4. |
- Chen, Gang, et al.
(författare)
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On the kinematic algebra for BCJ numerators beyond the MHV sector
- 2019
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; :11
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Tidskriftsartikel (refereegranskat)abstract
- The duality between color and kinematics present in scattering amplitudes of Yang-Mills theory strongly suggests the existence of a hidden kinematic Lie algebra that controls the gauge theory. While associated BCJ numerators are known on closed forms to any multiplicity at tree level, the kinematic algebra has only been partially explored for the simplest of four-dimensional amplitudes: up to the MHV sector. In this paper we introduce a framework that allows us to characterize the algebra beyond the MHV sector. This allows us to both constrain some of the ambiguities of the kinematic algebra, and better control the generalized gauge freedom that is associated with the BCJ numerators. Specifically, in this paper, we work in dimension-agnostic notation and determine the kinematic algebra valid up to certain ? ((epsilon i .epsilon j )(2)) terms that in four dimensions compute the next-to-MHV sector involving two scalars. The kinematic algebra in this sector is simple, given that we introduce tensor currents that generalize standard Yang-Mills vector currents. These tensor currents control the generalized gauge freedom, allowing us to generate multiple different versions of BCJ numerators from the same kinematic algebra. The framework should generalize to other sectors in Yang-Mills theory.
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| 5. |
- Fang, Du, et al.
(författare)
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Increased neuronal PreP activity reduces A beta accumulation, attenuates neuroinflammation and improves mitochondrial and synaptic function in Alzheimer disease's mouse model
- 2015
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 24:18, s. 5198-5210
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Tidskriftsartikel (refereegranskat)abstract
- Accumulation of amyloid-beta (A beta) in synaptic mitochondria is associated with mitochondrial and synaptic injury. The underlying mechanisms and strategies to eliminate A beta and rescue mitochondrial and synaptic defects remain elusive. Presequence protease (PreP), a mitochondrial peptidasome, is a novel mitochondrial A beta degrading enzyme. Here, we demonstrate for the first time that increased expression of active human PreP in cortical neurons attenuates Alzheimer disease's (AD)-like mitochondrial amyloid pathology and synaptic mitochondrial dysfunction, and suppresses mitochondrial oxidative stress. Notably, PreP-overexpressed AD mice show significant reduction in the production of proinflammatory mediators. Accordingly, increased neuronal PreP expression improves learning and memory and synaptic function in vivo AD mice, and alleviates A beta-mediated reduction of long-term potentiation (LTP). Our results provide in vivo evidence that PreP may play an important role in maintaining mitochondrial integrity and function by clearance and degradation of mitochondrial A beta along with the improvement in synaptic and behavioral function in AD mouse model. Thus, enhancing PreP activity/expression may be a new therapeutic avenue for treatment of AD.
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| 6. |
- Nan, Beiya, et al.
(författare)
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Microstructure and Properties of Porous SiC Ceramics Modified by CVI-SiC Nanowires
- 2019
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Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 21:5
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Tidskriftsartikel (refereegranskat)abstract
- Sintered porous SiC ceramics are modified with SiC nanowires prepared via chemical vapor infiltration (CVI). SiC nanowires are successfully grown within sintered porous SiC ceramics following vapor-liquid-solid growth. The diameter of the SiC nanowires is in the range of 200 nm-1 mu m, and first decreases with increasing input gas ratio (alpha = 50, 60, 70, and 80) and increases thereafter. The diameter of the nanowires decreases from the surface to the interior areas of the porous SiC ceramics. SiC nanowires effectively improve the mechanical properties of the porous SiC ceramics, and sample Ni-50 has the highest flexural strength of 33.91 MPa and fracture toughness of 0.79 MPa center dot m(1/2), which increases by 90.4% and 49.1% compared to an unmodified sample, respectively. Additionally, the presence of SiC nanowires leads to porous SiC ceramics with altered porosity and microstructure, and higher thermal conductivity. The porous SiC ceramics modified by CVI SiC nanowires satisfy the requirements of gas filtration applications and the pressure drop increases with decreasing apparent porosity. The porous SiC ceramics modified with CVI SiC nanowire has higher permeability than those resulting from the introduction of CVI-SiC matrix or CVD-SiC coating into porous SiC ceramics.
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| 7. |
- Wang, Sheng-Quan, et al.
(författare)
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Application of the principle of maximum conformality to the hadroproduction of the Higgs boson at the LHC
- 2016
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Ingår i: Physical Review D. - : American Physical Society (APS). - 2470-0010. ; 94:5
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Tidskriftsartikel (refereegranskat)abstract
- We present improved perturbative QCD (pQCD) predictions for Higgs boson hadroproduction at the LHC by applying the principle of maximum conformality (PMC), a procedure which resums the pQCD series using the renormalization group (RG), thereby eliminating the dependence of the predictions on the choice of the renormalization scheme while minimizing sensitivity to the initial choice of the renormalization scale. In previous pQCD predictions for Higgs boson hadroproduction, it has been conventional to assume that the renormalization scale mu(r) of the QCD coupling sigma(s)(mu(r)) is the Higgs mass and then to vary this choice over the range 1/2m(H) < mu(r) < 2m(H) in order to estimate the theory uncertainty. However, this error estimate is only sensitive to the nonconformal beta terms in the pQCD series, and thus it fails to correctly estimate the theory uncertainty in cases where a pQCD series has large higher-order contributions, as is the case for Higgs boson hadroproduction. Furthermore, this ad hoc choice of scale and range gives pQCD predictions which depend on the renormalization scheme being used, in contradiction to basic RG principles. In contrast, after applying the PMC, we obtain next-to-next-to-leading-order RG resummed pQCD predictions for Higgs boson hadroproduction which are renormalization-scheme independent and have minimal sensitivity to the choice of the initial renormalization scale. Taking m(H) = 125 GeV, the PMC predictions for the pp -> HX Higgs inclusive hadroproduction cross sections for various LHC center-of-mass energies are sigma(Incl vertical bar 7 TeV) = 21.21(-1.32)(+1.36) pb, sigma(Incl vertical bar 8 TeV) = 27.37(-1.59)(+1.65) pb, and sigma I-ncl vertical bar 13 TeV = 65.72(-3.01)(+3.46) pb. We also predict the fiducial cross section sigma fid(pp -> H -> gamma gamma): sigma(fid vertical bar 7 TeV) = 30.1(-2.2)(+2.3) fb, sigma(fid vertical bar 8 TeV) = 38.3(-2.8)(+2.9) fb, and sigma(fid vertical bar 13 TeV) = 85.8(-5.3)(+5.7) fb. The error limits in these predictions include the small residual high-order renormalization-scale dependence plus the uncertainty from the factorization scale. The PMC predictions show better agreement with the ATLAS measurements than the LHC Higgs Cross Section Working Group predictions which are based on conventional renormalization-scale setting.
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| 8. |
- You, Qiangwei, et al.
(författare)
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Microstructure and properties of porous SiC ceramics by LPCVI technique regulation
- 2017
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Ingår i: Ceramics International. - : Elsevier BV. - 0272-8842 .- 1873-3956. ; 43:15, s. 11855-11863
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Tidskriftsartikel (refereegranskat)abstract
- A new gradient pore structure in porous SiC ceramics was fabricated by low pressure chemical vapor infiltration (LPCVI). Effects of deposition duration on the mechanical properties and permeability of porous SiC ceramics were investigated. Results demonstrated that pore diameter and shapes decreased from the surface to the interior along with LPCVI duration. Porous SiC ceramics with deposition duration of 160 h exhibited flexural strength of 48.05 MPa and fracture toughness of 1.30 MPa m(1/2), where 221% and 189% improvements were obtained compared to porous SiC ceramics without LPCVI, due to CVI-SiC layer strengthening effect. Additionally, at the same gas velocity, pressure drop increase rate was faster due to apparent porosity and pore size change.
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| 9. |
- Yuan, Bo, et al.
(författare)
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Fabrication and microstructure of porous SiC ceramics with Al2O3 and CeO2 as sintering additives
- 2016
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Ingår i: Ceramics International. - : Elsevier BV. - 0272-8842 .- 1873-3956. ; 42:11, s. 12613-12616
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, porous silicon carbide ceramics were prepared via spark plasma sintering at relatively low temperatures using Al2O3 and CeO2 as sintering additives. Sacrificial template was selected as the pore forming mechanism, and gelcasting was used to fix the slurry in a short time. The evolution process of the microstructures during different steps was observed by SEM. The influence of the sintering temperature and sintering additives on the shrinkage and porosity of the samples was studied. The microstructures of different samples were characterized, and the mechanical properties were also evaluated.
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| 10. |
- Yuan, Bo, et al.
(författare)
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Preparation and properties of porous silicon carbide based ceramic filter
- 2016
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 684, s. 613-615
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Tidskriftsartikel (refereegranskat)abstract
- Porous silicon carbide ceramics with high open porosity and large pore size are usually applied as filters for the cleaning of hot dust gases. However, the large porosity and large pore size will decrease the mechanical properties. In the present study, porous SiC ceramics were prepared using bentonite as bonding phase. The effects of sintering temperature on the microstructure and the compressive strength were studied. Bentonite could melt and spread on the surface of silicon carbide particles at all the sintering temperatures. However, the bonding effects were very different at different temperatures.
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