| 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. |
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| 3. |
- Xu, Tao, et al.
(författare)
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A pillar-array based 2-dimensional photonic crystal microcavity
- 2009
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 94, s. 241110-
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Tidskriftsartikel (refereegranskat)abstract
- Experimental results are presented for a high quality factor cavity based on pillar arrays. The cavityis formed from a square lattice of silicon pillars of finite height. The quality factor of the fundamental mode is about 7300 when the cavity is in air and 7800 when it is immersed in water.Since a pillar array has a large percent of connected void space and confines TM modes effectively,it has great promise for use in numerous areas including biochemical sensing and quantum cascade lasers.
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| 4. |
- Xu, Tao, et al.
(författare)
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Pillar-array based optical sensor
- 2010
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Ingår i: Optics Express. - 1094-4087. ; 18:6, s. 5420-5425
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Tidskriftsartikel (refereegranskat)abstract
- An optical microcavity based on pillar arrays has been fabricated in Si/SiO2 material system. Transmission measurement was taken and a quality factor as high as 27,600 was observed. This cavity was tested for sensing applications by immersing into optical fluids with accurate refractive indices. For refractive index change of 0.01, a resonance peak wavelength shift of 3.5 nm was measured. We also compare cavities consisting of pillars with different aspect ratios.
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| 5. |
- Xu, Tao, et al.
(författare)
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Silicon-on-insulator nanopillar-array optical sensor
- 2011
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Ingår i: Progress in Biomedical Optics and Imaging - Proceedings of SPIE. - : SPIE - International Society for Optical Engineering. - 9780819484451
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Konferensbidrag (refereegranskat)abstract
- Pillar-array based optical cavities have unique properties, e.g., having a large and connected low dielectric index space (normally air space), having a large percent of electric field energy in air and standing on a substrate. These properties make them well suitable to make ultra compact and highly sensitive label-free optical sensors to detect bio-/chemical reactions. We designed, fabricated, and measured a silicon-on-insulator pillar array microcavity that possesses a quality factor as high as 27,600. We studied its sensitivity for both bulk index change and surface index modification. As a bulk index sensor, for environmental refractive index change of 0.01, a resonance peak wavelength shift of 3.5 nm was measured. As a surface index sensor, the simulations show, for a coating with thickness of 1 nm, the resonance wavelength shifts as large as 2.86 nm. Combining with a sharp 0.06 nm wide resonance peak, our pillar-array sensor is able to resolve ultra small bulk and surface refractive index changes caused by target molecules.
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| 6. |
- Gan, Zhixing, et al.
(författare)
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Electron transition pathways of photoluminescence from 3C-SiC nanocrystals unraveled by steady-state, blinking and time-resolved photoluminescence measurement
- 2016
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Ingår i: Journal of Physics D. - : Institute of Physics (IOP). - 0022-3727 .- 1361-6463. ; 49:27
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Tidskriftsartikel (refereegranskat)abstract
- The cubic phase SiC nanocrystals (3C-SiC NCs) have been extensively studied for electronics and photonics applications. In this work we study the electron transition pathways of photoluminescence (PL) from 3C-SiC NCs. It is found through measuring the steady-state, blinking and time-resolved PL spectra that surface passivation by glycerol improved the steady-state PL intensity (it does not modify the emission wavelength) and the NCs fluoresced more steadily. The PL decay lifetimes are shown to be the same when the detection wavelength is modified to scan the broad PL peak, implying that the broad PL peak is originated from the distribution of NCs' sizes. Furthermore, the PL decay lifetimes are not modified by the surface passivation. It is concluded that for PL, the electron is photoexcited from the ground state in the NC to a high-energy excited state, relaxes to the first excited state then radiatively recombines to the ground state to emit a photon. The photoexcited electron at the high-energy excited state could transit to the surface state, resulting in a reduced PL intensity and a decreased on-state dwell time in the blinking trajectory. The PL decay lifetime data implies that the two principal electron transition pathways of (a) high-energy excited state double right arrow the first excited state double right arrow the ground state, and (b) high-energy excited state double right arrow surface state double right arrow the ground state are independent from each other. We strongly believe that such a deep knowledge about 3C-SiC NCs will open new doors to harness them for novel applications.
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| 7. |
- Liang, Wang, et al.
(författare)
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Life cycle assessment of blast furnace ironmaking processes : A comparison of fossil fuels and biomass hydrochar applications
- 2023
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 345
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Tidskriftsartikel (refereegranskat)abstract
- The impact of the iron and steel production process on the ecological environment cannot be ignored. This study aims to assess the impact of life cycle assessment on the traditional fossil fuel blast furnace ironmaking process and the biomass hydrochar blast furnace ironmaking process. The Simapro v9.0 software is used to comprehensively evaluate the life cycle impacts of biomass hydrochar in the blast furnace ironmaking process. The results show that the life cycle impact categories of the blast furnace ironmaking process mainly include global warming, non-renewable energy and respiratory inorganics. The global warming impact of the ironmaking process using hydrochar is 2054.00 kg CO2 eq, which is 420.61 kg CO2 eq less than that of traditional blast furnace ironmaking process. The global warming impact is mainly reflected in the emission of CO2 gas, and the main source is the generation of blast furnace gas and the use of sinter. The respiratory inorganics impact is mainly manifested in the emission of nitrogen oxides, sulfur oxides and particulates, which mainly comes from the mining of iron ore and the production of sinter. The non-renewable energy impact mainly comes from the coal resources, and the use of other renewable energy such as biomass energy is an important way to reduce the impact. Therefore, biomass hydrochar used in the metallurgical process is more suitable for sustainable devel-opment of the ecological environment.
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| 8. |
- Qian, Zhenchao, et al.
(författare)
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Triboelectric nanogenerators made of polybenzazole aerogels as fire-resistant negative tribo-materials
- 2019
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Ingår i: Nano Energy. - : ELSEVIER. - 2211-2855 .- 2211-3282. ; 64
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Tidskriftsartikel (refereegranskat)abstract
- Flame-retardant negative tribo-materials are desirable for triboelectric nanogenerators (TENGs) using under harsh conditions, such as thermal power fields and aerospace. The existed negative tribo-materials are mainly polymeric materials, and their high-temperature stability and fire resistance still need to be improved. Herein, poly(p-phenylene benzobisoxazole) aerogels (PBOAs) were used as the negative tribo-materials in TENGs. Because of the large porosity and high specific surface area, the resultant TENGs exhibit maximum open circuit voltage, short-circuit current density and charge density of 40 V, 2.9 mA m(-2) and 72 mu C m(-2), respectively. The device can light 36 LED bulbs and charge the capacitor to 10 V within 250 s. The device can also be used as a self-powered, highly sensitive sensor for monitoring human motion and even slight collisions with an impulse of only 3 mu N s. PBOA has been paired with aluminum foil to fabricate PBOA/Al TENGs, which exhibit V on of 32 V(, )J(SC) of 1.2 mA M-2 and charge density of 32 mu C M-2 at a temperature as high as 350 degrees C, demonstrating the possibility of application of TENGs in high-temperature environments.
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| 9. |
- Wang, Guangwei, et al.
(författare)
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Application of catalysts in biomass hydrothermal carbonization for the preparation of high-quality blast furnace injection fuel
- 2023
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 283
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Tidskriftsartikel (refereegranskat)abstract
- The low energy density of biomass is a crucial limitation for their application in the steel industry. This study used catalyst-catalysed hydrothermal carbonization (HTC) to prepare higher-quality hydrochar from biomass. The effects of acid-base homogeneous catalysts (Fe(NO3)3·9H2O and CaO), liquid phase product (circulating water) and carbonization temperatures on the physicochemical properties and microscopic morphology of hydrochars were investigated. The results showed that higher carbonization temperature, circulating water and Fe(NO3)3·9H2O all raised the higher heating value (HHV) of hydrochar. When 4% of Fe(NO3)3·9H2O was added, the HHV of hydrochar reached 30.05 MJ/kg, which was 1.15 times higher than without catalysts. The above three conditions can also make the ordering degree in the carbonaceous structure lower ordered and enhance the reaction performance of the hydrochar. Meanwhile, the addition of Fe(NO3)3·9H2O at 240 °C can reduce the hydrochar ignition and burnout temperatures and enhance the combustion performance. Moreover, it was demonstrated that circulating water promoted the HTC more than deionized water. In conclusion, adding Fe(NO3)3·9H2O or circulating water to the HTC process can produce higher-quality hydrochar.
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| 10. |
- Wang, Guangwei, et al.
(författare)
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Preparation of Biomass Hydrochar and Application Analysis of Blast Furnace Injection
- 2023
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 16:3
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Tidskriftsartikel (refereegranskat)abstract
- Hydrothermal carbonization (HTC) technology was used to carbonize and improve biomass raw material to obtain hydrochar. The effects of HTC temperature and holding time on the yield, composition, structure, combustion behavior, and safety of hydrochar were studied systematically. In addition, the results show that with the increase in HTC temperature and the prolongation of holding time, the yield of hydrochar gradually reduces, the fixed carbon content of hydrochar increases, the volatile content decreases, and a large number of ash and alkali metals enter the liquid phase and are removed. Further, the analysis of the combustion properties and the structure of hydrochar can be observed in that, as the HTC process promotes the occurrence of polymerization reactions, the specific surface area gradually reduces, the degree of carbon ordering increases, and the combustion curve moves toward the high-temperature zone and gradually approaches bituminous coal. Since biomass hydrochar has the characteristic of being carbon neutral, blast furnace injection hydrochar can reduce CO2 emissions, and every 1 kg/tHM of biomass hydrochar can reduce CO2 emissions by 1.95 kg/tHM.
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