| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Liu, Chunyu, et al.
(författare)
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Experimental study on effects of ammonia enrichment on the thermoacoustic instability of lean premixed swirling methane flames
- 2024
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Ingår i: Fuel. - 0016-2361. ; 357
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Tidskriftsartikel (refereegranskat)abstract
- Ammonia (NH3) has recently emerged as a promising carbon-free energy carrier. Further development and application of NH3 as fuel in the gas turbine industry can significantly reduce the emissions of carbon dioxide (CO2) and contribute to the achievement of a carbon–neutral society. This study experimentally examined the thermoacoustic instability characteristics of a laboratory-scaled lean premixed gas turbine model combustor operated with different NH3 blending ratios with methane (CH4). Experiments conducted under a wide range of inlet velocities and equivalence ratios suggest that NH3 concentration is critical in determining the characteristics of the instability. Specifically, when the NH3 proportion is less than 50 %, the addition of NH3 causes a mode transition of the instability. However, when the content of NH3 is greater than 50 %, it is shown that the instabilities are suppressed, indicating that the addition of a certain amount of NH3 can enhance the stability of CH4 flames. Additional analysis of flame dynamics reveals that the introduction of NH3 causes the lengthening of the flame front and weakens heat release rate fluctuations in the flame root regions. Further Proper Orthogonal Decomposition (POD) analysis of the flow field shows that the instability modes are strongly coupled with periodic vortex motions of the flow dynamics along the shear layers. Finally, the mode shifting phenomena is successfully predicted by low-order thermoacoustic network modeling. It is suggested that the change in convective time delay caused by NH3 addition is responsible for such transitions.
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| 3. |
- Liu, Yadi, et al.
(författare)
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Enhancing the Molecular Order and Vertical Component Distribution of the P3HT/O-IDTBR System during Layer-by-Layer Processing
- 2023
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Ingår i: Macromolecular rapid communications. - : WILEY-V C H VERLAG GMBH. - 1022-1336 .- 1521-3927.
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Tidskriftsartikel (refereegranskat)abstract
- The molecular order and vertical component distribution are critical to enhance the charge transport in layer-by-layer (LbL) processed active layer. However, the excessive inter-diffusion between donor and acceptor layers during LbL processing irrepressibly reduces their ordered packing. Herein, a novel tactic to optimize the molecular order and vertical morphology of the active layer through suppressing the deep penetration of (5Z,5 & PRIME;Z)-5,5 & PRIME;-((7,7 & PRIME;-(4,4,9,9-tetraoctyl-4,9-dihydro-s-indaceno[1,2-b:5,6 -b & PRIME;]dithiophene-2,7-diyl)bis(benzo[c][1,2,5]thiadiazole-7,4-diyl))bis(methanylylidene)) bis(3-ethyl-2-thioxothiazolidin-4-one) (O-IDTBR) to poly(3-hexylthiophene) (P3HT) film during LbL processing is proposed. This is enabled by inducing the formation of P3HT nanofibers through ultraviolet (UV) irradiation and solution aging. During the LbL processing, these nanofibers with high crystallinity reduce the damage of O-IDTBR solution to P3HT film and restrict the penetration of O-IDTBR into P3HT matrix. As a result, the P3HT nanofibers are preserved and the degree of vertical phase separation is enlarged in the LbL-processed film. Meanwhile, the molecular order of both components is enhanced. The resulting morphology that featured as intertwined P3HT nanofibers/O-IDTBR network efficiently promotes charge transport and extraction, boosting the power conversion efficiency (PCE) of the devices from 6.70 & PLUSMN; 0.12% to 7.71 & PLUSMN; 0.10%.
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| 4. |
- Mottamchetty, Venkatesh, et al.
(författare)
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Application of vector beams for enhanced high-order harmonics generation in laser-induced plasmas
- 2022
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Ingår i: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 30:10, s. 17080-17093
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Tidskriftsartikel (refereegranskat)abstract
- High-order harmonics driven by phase- and polarization-structured femtosecond pulses are unique sources of the extreme ultraviolet vortex and vector beams, which have various applications. Here, we report the generation of intense high-order harmonics during propagation of the polarization-structured vector beams (radially polarized beam, azimuthally polarized beam, and their superposition) through the laser-induced plasmas (In, C, CdS, Zns, Ag2S). Low-order harmonics became stronger with radially polarized and azimuthally polarized driving beams compared with the linearly polarized beams, which is explained on the basis of phase matching and specific properties of vector beams. Contrary to that, the resonance-enhanced harmonic generated in the indium plasma in the case of radially polarized and azimuthally polarized beams was twice weaker compared with the harmonic generated by the LP beam due to modification in the resonant transition selection rules leading to a decrease of the oscillator strength of ionic transitions. Harmonic cut-off and intensity in the case of superposition of the radially and azimuthally polarized beams were lesser compared with the cases of the individual (radially polarized and azimuthally polarized) beams. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
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| 5. |
- Pan, Jiaqi, et al.
(författare)
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Alleviating excessive aggregation of a non-fullerene acceptor by delaying and shortening the crystallization time to reduce the energy loss of ternary organic solar cells
- 2024
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Ingår i: Journal of Materials Chemistry C. - : ROYAL SOC CHEMISTRY. - 2050-7526 .- 2050-7534.
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Tidskriftsartikel (refereegranskat)abstract
- The key factor restricting the power conversion efficiency (PCE) of organic solar cells (OSCs) is the energy loss (Eloss), which is the difference between the optical bandgap (Eg) of the active layer and open-circuit voltage (VOC) of the device. To achieve lower Eloss, it is necessary to obtain an appropriate donor-acceptor phase separation size to accelerate exciton dissociation and inhibit the recombination process. However, in most high-efficiency non-fullerene systems, acceptors often exhibit excessive aggregation phenomena. The decrease in the interface area leads to a decrease in exciton dissociation efficiency, which increases the energy loss. Herein, we report a ternary strategy to decrease the crystallization time of the acceptor and inhibit the excessive aggregation condition of a non-fullerene acceptor. We chose a donor poly{[4,8-bis[5-(2-ethylhexyl)-4-fluoro-2-thienyl]benzo[1,2-b:4,5-b ']-dithiophene-2,6-diyl]-alt-[2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxo-4H,8H-benzo[1,2-c:4,5-c ']dithiophene-1,3-diyl]]} (PM6) and a non-fullerene acceptor (2,2 '-((2Z,2 ' Z)-((12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2 '',3 '':4 ',5 ']thieno[2 ',3 ':4,5]pyrrolo[3,2-g]thieno[2 ',3 ':4,5]thieno[3,2-b]indole-2,10-diyl)bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile) (Y6) as the model system. Y6 is prone to forming a tightly packed structure due to its planar curved skeleton. To suppress the excessive aggregation, we chose poly[2,2 '-((2Z,2 ' Z)-((12,13-bis(2-octyldodecyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2 '',3 '':4 ',5 ']thieno[2 ',3 ':4,5]pyrrolo[3,2-g]thieno[2 ',3 ':4,5]thieno[3,2-b]indole-2,10-diyl)bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile-co-2,5-thiophene] (PY-IT) as a second acceptor, which has good compatibility with Y6. By using in situ UV-visible absorption spectroscopy to monitor the film formation kinetics of Y6, it was found that after adding 15 wt% PYIT, the total crystallization time of Y6 decreased and the excessive aggregation of Y6 was inhibited. In the PM6:Y6 system, Y6 only had one crystallization and film-forming process. While in the PM6:Y6+15 wt% PYIT system, the process of film formation became more complex, with two stages of aggregation. PYIT crystallized before Y6, when Y6 began to crystallize, PYIT has occupied a portion of the crystallization growth space. What is more, PYIT delayed the crystallization process of Y6, and the change in the acceptor peak position showed a stable region. After that, Y6 began to aggregate and the crystallization time of Y6 was shorter than that of the binary system. As a result, PYIT alleviated the excessive aggregation of Y6, resulting in better mixing between the non-fullerene acceptor and the donor, increasing the interface area and enabling faster dissociation of excitons. In addition, the vertical phase separation of the active layer has also been optimized, allowing more donors enriched near the anode, enhancing the efficiency of charge extraction. The improved morphology of the active layer results in a better interface area, which can not only ensure exciton dissociation and charge generation, but also reduce the transfer time, which is conducive to reducing energy loss. As a result, Eloss reduced from 0.559 eV to 0. 539 eV, and the optimized ternary OSC exhibited a PCE of 17.05%. PYIT was added to the PM6:Y6 system to delay and shorten the crystallization time of Y6. The ternary strategy has been successfully proven to increase the D/A interface area for faster exciton dissociation. The Eloss decreased (0.559 eV to 0.539 eV), and the PCE increased (15.40% to 17.05%).
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| 6. |
- Yang, Jinglun, et al.
(författare)
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Robust and Large-Area Calix[4]pyrrole-Based Nanofilms Enabled by Air/DMSO Interfacial Self-Assembly-Confined Synthesis
- 2021
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society. - 1944-8244 .- 1944-8252. ; 13:2, s. 3336-3348
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Tidskriftsartikel (refereegranskat)abstract
- The modular construction of defect-free nanofilms with a large area remains a challenge. Herein, we present a scalable strategy for the preparation of calix[4]pyrrole (C[4]P)-based nanofilms through acryl hydrazone reaction conducted in a tetrahydrazide calix[4]pyrrole (CPTH)-based self-assembled layer at the air/DMSO interface. With this strategy, robust, regenerable, and defect-free nanofilms with an exceptionally large area (?750 cm2) were constructed. The thickness and permeability of the film systems can be fine-tuned by varying the precursor concentration or by changing another building block. A typical nanofilm (C[4]P-TFB, ?67 nm) depicted high water flux (39.9 L m-2 h-1 under 1 M Na2SO4), narrow molecular weight cut-off value (?200 Da), and promising antifouling properties in the forward osmosis (FO) process. In addition, the nanofilms are stable over a wide pH range and tolerable to different organic solvents. Interestingly, the introduction of C[4]P endowed the nanofilms with both outstanding mechanical properties and unique group-selective separation capability, laying the foundation for wastewater treatment and pharmaceutical concentration.
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| 7. |
- Zhao, Yu, et al.
(författare)
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Hierarchical Pattern Exploitation for Efficient Electromagnetic Analysis of Finite Periodic Arrays
- 2022
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 70:12, s. 12417-12422
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Tidskriftsartikel (refereegranskat)abstract
- The hierarchical pattern exploitation (HPE) method is proposed for the efficient electromagnetic analysis of finite periodic arrays. Instead of taking advantage of the Toeplitz symmetry by discretizing integral equations, HPE partitions the array hierarchically to form considerably larger geometrical repetitions, which result in identical interaction blocks inside the system matrix. These interaction blocks representing patterns are characterized and hashed to generate a directory, which maps the patterns to the references of the submatrices. Due to the large proportion of repetitions in hierarchical matrix (H-matrix), HPE accelerates the matrix assembly and reduces the required storage drastically. Numerical examples show that HPE outperforms the classical H-matrix by a large margin with much less storage and CPU time cost for the analysis of finite periodic arrays. Compared with the multilevel fast multipole algorithm and the characteristic basis function method, HPE also demonstrates competitive performance, which validates the effectiveness and efficiency of the proposed method.
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