| 1. |
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- 2019
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Journal article (peer-reviewed)
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| 2. |
- Dubsky, Brendan Frisk, et al.
(author)
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Simple modules over the Lie algebras of divergence zero vector fields on a torus
- 2019
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In: Forum mathematicum. - : Walter de Gruyter GmbH. - 0933-7741 .- 1435-5337. ; 31:3, s. 727-741
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Journal article (peer-reviewed)abstract
- Let n >= 2 be an integer, S-n the Lie algebra of divergence zero vector fields on an n-dimensional torus, and K-n the Weyl algebra over the Laurent polynomial algebra A(n) = C[x(1)(+/- 1), x(2)(+/- 1), . . . , x(n)(+/- 1)]. For any sln-module V and any module P over K-n, we define an S-n-module structure on the tensor product P circle times V. In this paper, necessary and sufficient conditions for the S-n-modules P circle times V to be simple are given, and an isomorphism criterion for nonminuscule S-n-modules is provided. More precisely, all nonminuscule S-n-modules are simple, and pairwise nonisomorphic. For minuscule S-n-modules, minimal and maximal submodules are concretely determined.
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| 3. |
- Elsik, Christine G., et al.
(author)
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The Genome Sequence of Taurine Cattle : A Window to Ruminant Biology and Evolution
- 2009
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 324:5926, s. 522-528
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Journal article (peer-reviewed)abstract
- To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
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| 4. |
- He, Yunjuan, et al.
(author)
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Cobalt oxides coated commercial Ba0.5Sr0.5Co0.8Fe0.2O3-delta as high performance cathode for low-temperature SOFCs
- 2016
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In: Electrochimica Acta. - : Elsevier. - 0013-4686 .- 1873-3859. ; 191, s. 223-229
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Journal article (peer-reviewed)abstract
- In order to improve the catalytic activity of commercial Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) for low-temperature solid oxide fuel cells (LTSOFC) (300-600 degrees C), CoOx has been used to modify the commercial BSCF through a solution coating approach. Phase and morphology of samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy-dispersive spectrometry (EDS), respectively. BSCF with 10 wt% CoOx exhibited an improved conductivity of 44 S/cm, and achieved a peak power density of 463 mW/cm(2) at 550 degrees C for LTSOFC, which is a 100% enhancement than that with the BSCF cathode. The cathode oxygen reduction reaction (ORR) promoted by CoOx and enhanced device performance mechanism have been proposed. This work provides a new way for the exploitation of high effective cathode materials for LTSOFCs.
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| 5. |
- López-Delgado, R., et al.
(author)
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Enhanced conversion efficiency in Si solar cells employing photoluminescent down-shifting CdSe/CdS core/shell quantum dots
- 2017
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In: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7:1
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Journal article (peer-reviewed)abstract
- Silicon solar cells have captured a large portion of the total market of photovoltaic devices mostly due to their relatively high efficiency. However, Silicon exhibits limitations in ultraviolet absorption because high-energy photons are absorbed at the surface of the solar cell, in the heavily doped region, and the photo-generated electron-hole pairs need to diffuse into the junction region, resulting in significant carrier recombination. One of the alternatives to improve the absorption range involves the use of down-shifting nano-structures able to interact with the aforementioned high energy photons. Here, as a proof of concept, we use downshifting CdSe/CdS quantum dots to improve the performance of a silicon solar cell. The incorporation of these nanostructures triggered improvements in the short circuit current density (Jsc, from 32.5 to 37.0 mA/cm2). This improvement led to a ∼13% increase in the power conversion efficiency (PCE), from 12.0 to 13.5%. Our results demonstrate that the application of down-shifting materials is a viable strategy to improve the efficiency of Silicon solar cells with mass-compatible techniques that could serve to promote their widespread utilization.
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| 6. |
- López-Delgado, R., et al.
(author)
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Influence of photo-luminescent CdSe/CdS core shell quantum dots in solar cell efficiency
- 2016
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In: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 773:1
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Journal article (peer-reviewed)abstract
- We report the synthesis and characterization of CdSe/CdS core-shell quantum dots (CdSe/CdS-QDs) that exhibit absorption in the UV range of the solar spectrum and emit photons with wavelengths centered around 625 nm, a wavelength that is well suited for silicon absorption and electron-hole pair generation. We also report the fabrication and characterization of single crystal silicon (c-Si) solar cells with and without the aforementioned photo luminescent, down-shifting CdSe/CdS- QDs. The incorporation of these nanostructures triggered improvements in the performance of the devices, particularly in the open circuit voltage (Voc) and short circuit current density (Jsc) for which the measured values showed an increase from 543 to 546 mV and from 32.5 to 37.0 mA/cm2, respectively. The combined effect of the improved values led to an increment in the power conversion efficiency (PCE) from 12.01 to 13.54%. This increase represents a 12.7% improvement in the PCE of the fabricated devices. The effort described herein is considered a good fit to the generalized trend to improve the efficiency of solar cells with mass-compatible techniques that could serve to promote their widespread utilization
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| 7. |
- Tong, Xin, et al.
(author)
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Heavy Metal-free, Near-infrared Colloidal Quantum Dots for Efficient Photoelectrochemical Hydrogen Generation
- 2017
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In: Nano Energy. - : Elsevier. - 2211-2855. ; 31, s. 441-449
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Journal article (peer-reviewed)abstract
- Photoelectrochemical (PEC) hydrogen generation based on colloidal quantum dots (QDs) is very promising because of its high solar energy to fuel conversion efficiency and low fabrication costs. However, its commercial development is hindered by various challenges, including the widespread use of toxic heavy metal–based QDs as sensitizers. We report an environmentally friendly, high efficiency PEC device in which the photoanode consists of a mesoporous TiO2 film sensitized with heavy metal-free, near-infrared (NIR) colloidal CuInSexS2-x (CISeS) QDs. To reduce surface-related traps, we grew an ultrathin ZnS shell on the CISeS core QDs by cation exchange. The PEC cell based on this core/shell CISeS/ZnS QDs exhibits suppressed charge recombination and a saturated photocurrent density of ~5.3 mA/cm2 under one sun illumination (AM 1.5 G, 100 mW/cm2). In addition, the as-prepared PEC device shows an outstanding stability, exhibiting a drop of only 23% after 9 h illumination. The success in using such core/shell CISeS/ZnS QDs paves the way to realize environment-friendly, high efficiency and cost-effective PEC devices for hydrogen production.
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| 8. |
- Wang, Tingting, et al.
(author)
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Prevalence and influencing factors of wheeze and asthma among preschool children in Urumqi city : a cross-sectional survey
- 2023
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In: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13:1
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Journal article (peer-reviewed)abstract
- To investigate the prevalence and indoor environmental influencing factors of wheeze and asthma among preschool children in Urumqi, Xinjiang, China to provide a strong basis for prevention and control. In August 2019, a cross-sectional study involving 8153 preschool children was conducted in 60 kindergartens in Urumqi. The ALLHOME-2 questionnaire was used for childhood wheeze and asthma survey, and the dampness in buildings and health (DBH) questionnaire was used for the childhood home dwelling and living environment survey. Multivariate unconditional logistic regression was then used to analyze the potential influencing factors of childhood asthma and wheeze. The prevalence of wheeze and asthma in children was 4.7% and 2.0%, respectively. Multivariate unconditional logistic regression results suggested that ethnicity other than the Han Chinese (odds ratio (OR) 1.39, 95% confidence interval (CI) 1.05-1.84), caesarean section (OR 1.24, 95% CI 1.00-1.53), family history of asthma (OR 5.00, 95% CI 3.36-7.44), carpet or floor bedding at home (OR 1.40, 95% CI 1.05-1.87), purchasing new furniture in the mother's residence during pregnancy (OR 1.58, 95% CI 1.06-2.36), pet keeping in the residence at aged 0-1 year (OR 1.55, 95% CI 1.13-2.13), passive smoking by child in the current residence (OR 1.35, 95% CI 1.01-1.80), and having mould or hygroma in the child's residence at aged 0-1 year (OR 1.72, 95% CI 1.12-2.64) were risk factors for wheeze. In addition, Girls (OR 0.73, 95% CI 0.59-0.90) was a protective factor for wheeze. Caesarean section (OR 1.46, 95% CI 1.06-2.00), family history of asthma (OR 7.06, 95% CI 4.33-11.53), carpet or floor bedding at home (OR 2.20, 95% CI 1.50-3.23), and pet keeping in the residence at aged 0-1 year (OR 1.64, 95% CI 1.04-1.83) were risk factors for asthma, whereas Girls (OR 0.58, 95% CI 0.42-0.80) was a protective factor for asthma. This survey indicates that the purchase of new furniture, the placement of carpet or floor bedding in the child's residence, the pets keeping, room dampness or moldy phenomena, and passive smoking may all contribute to an elevated risk of wheeze or asthma in children.
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| 9. |
- Wu, Zhaofei, et al.
(author)
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The sensitivity of ginkgo leaf unfolding to the temperature and photoperiod decreases with increasing elevation
- 2022
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In: Agricultural and Forest Meteorology. - : Elsevier BV. - 0168-1923. ; 315
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Journal article (peer-reviewed)abstract
- Climate change substantially affects plant phenology, resulting in earlier vegetation onset across temperate and boreal regions. Phenological shifts caused by warming may alter species interactions across trophic levels because of species-specific responses, and influence the reproductive success of dioecious species if the phenological sensitivity to warming (ST) differs between genders. We used twigs collected from male and female gingko trees at three elevations on Tianmu Mountain in eastern China. The twigs were cultivated in climate chambers to determine the effects of three temperatures (10, 15, and 20 °C) and two photoperiods (8 and 16 h). We observed slightly earlier leaf unfolding dates in male twigs (1 day), and a higher heat requirement (growing degree hours) for leaf unfolding in female (14,334 ± 588 °C) compared to male twigs (13,874 ± 551 °C). Similar responses to temperature (ST = 3.7 days °C−1), photoperiod and elevation were observed across genders. The long photoperiod treatment shortened the time to leaf unfolding by 9.1 days, but temperature and photoperiod effects on leaf unfolding differed significantly depending on the elevation of the donor trees. Specifically, ST was higher (4.17 days °C−1) and the photoperiod effect on ST was larger (decreased by 1.15 days °C−1) at the lowest elevation than at the higher elevations (ST = 3.26 days °C−1; decreased by 0.48 days °C−1). This may be related to environment-induced local adaptations and self-protection mechanisms of trees at high elevations to avoid frost damage. Our results indicate that the photoperiod and genetic adaptations to local environments influenced the warming-induced phenological responses in ginkgo, but these responses were generally similar between the genders. For a given species, individuals in different climates may exhibit different phenological responses to higher temperatures, with individuals in warmer regions likely becoming increasingly limited by the photoperiod as the climate warms further.
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| 10. |
- Zhao, Haiguang, et al.
(author)
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Absorption Enhancement in “Giant” Core/Alloyed-Shell Quantum Dots for Luminescent Solar Concentrator
- 2016
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In: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 12:38, s. 5354-5365
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Journal article (peer-reviewed)abstract
- Luminescent solar concentrators (LSCs) can potentially reduce the cost of solar cells by decreasing the photoactive area of the device and boosting the photoconversion efficiency (PCE). This study demonstrates the application of “giant” CdSe/CdxPb1–xS core/shell quantum dots (QDs) as light harvesters in high performance LSCs with over 1.15% PCE. Pb addition is critical to maximize PCE. First, this study synthesizes “giant” CdSe/CdxPb1–xS QDs with high quantum yield (40%), narrow size distribution (<10%), and stable photoluminescence in a wide temperature range (100–300 K). Subsequently these thick alloyed-shell QDs are embedded in a polymer matrix, resulting in a highly transparent composite with absorption spectrum covering the range 300–600 nm, and are applied as active material for prototype LSCs. The latter exhibits a 15% enhancement in efficiency with respect to 1% PCE of the pure-CdS-shelled QDs. This study attributes this increase to the contribution of Pb doping. The results demonstrate a straightforward approach to enhance light absorption in “giant” QDs by metal doping, indicating a promising route to broaden the absorption spectrum and increase the efficiency of LSCs.
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