| 1. |
|
|
| 2. |
- Liu, Tong, et al.
(författare)
-
Semitransparent polymer solar cell/triboelectric nanogenerator hybrid systems: Synergistic solar and raindrop energy conversion for window-integrated applications
- 2022
-
Ingår i: Nano Energy. - : ELSEVIER. - 2211-2855 .- 2211-3282. ; 103
-
Tidskriftsartikel (refereegranskat)abstract
- Development of photovoltaic (PV)-derived hybrid power systems can overcome the weather-dependent elec-tricity production and increase the amount of dispatchable renewable energy generation. Herein, monolithic hybrid devices are developed via rational integration of high-performance semitransparent polymer solar cells (ST-PSCs) and liquid-solid triboelectric nanogenerators (TENGs). High-performance PSCs with efficiencies of 17.4% for rigid and 15.7% for flexible devices are achieved. Further electrode modifications and integration of transparent TENGs synergistically balance the above-bandgap photon harvesting and transparency in a broad wavelength range (380 -1000 nm), yet significantly reduce the transmittance in the near-infrared wavelength range (1000 -2500 nm) of hybrid devices. The hybrid devices simultaneously provide high visible light transparency, good color fidelity, efficient heat resistance and possibility to integrate on rigid and flexible substrates. The hybrid devices attain a high solar conversion efficiency of 10.1% under 1 sun, indicating efficient light-to-electricity conversion (a maximum electrical power output: 101 W m-2) on sunny days. The hybrid devices can also generate a maximum electrical power output of 2.62 W m- 2 through waterdrop energy con-version, implying complementary green electricity production on rainy days. The controlled ambient tempera-ture and specific transmittance windows provided by the hybrid devices sustain plant growth and highlight their great potential in agricultural applications. Gratifyingly, this work demonstrates the first example of ST-PSC/ TENG hybrid systems for scaling up renewable power generation in different weather conditions, considering architectural and agricultural applications.
|
|
| 3. |
- Lozano, Rafael, et al.
(författare)
-
Measuring progress from 1990 to 2017 and projecting attainment to 2030 of the health-related Sustainable Development Goals for 195 countries and territories: a systematic analysis for the Global Burden of Disease Study 2017
- 2018
-
Ingår i: The Lancet. - : Elsevier. - 1474-547X .- 0140-6736. ; 392:10159, s. 2091-2138
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Efforts to establish the 2015 baseline and monitor early implementation of the UN Sustainable Development Goals (SDGs) highlight both great potential for and threats to improving health by 2030. To fully deliver on the SDG aim of “leaving no one behind”, it is increasingly important to examine the health-related SDGs beyond national-level estimates. As part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017), we measured progress on 41 of 52 health-related SDG indicators and estimated the health-related SDG index for 195 countries and territories for the period 1990–2017, projected indicators to 2030, and analysed global attainment. Methods: We measured progress on 41 health-related SDG indicators from 1990 to 2017, an increase of four indicators since GBD 2016 (new indicators were health worker density, sexual violence by non-intimate partners, population census status, and prevalence of physical and sexual violence [reported separately]). We also improved the measurement of several previously reported indicators. We constructed national-level estimates and, for a subset of health-related SDGs, examined indicator-level differences by sex and Socio-demographic Index (SDI) quintile. We also did subnational assessments of performance for selected countries. To construct the health-related SDG index, we transformed the value for each indicator on a scale of 0–100, with 0 as the 2·5th percentile and 100 as the 97·5th percentile of 1000 draws calculated from 1990 to 2030, and took the geometric mean of the scaled indicators by target. To generate projections through 2030, we used a forecasting framework that drew estimates from the broader GBD study and used weighted averages of indicator-specific and country-specific annualised rates of change from 1990 to 2017 to inform future estimates. We assessed attainment of indicators with defined targets in two ways: first, using mean values projected for 2030, and then using the probability of attainment in 2030 calculated from 1000 draws. We also did a global attainment analysis of the feasibility of attaining SDG targets on the basis of past trends. Using 2015 global averages of indicators with defined SDG targets, we calculated the global annualised rates of change required from 2015 to 2030 to meet these targets, and then identified in what percentiles the required global annualised rates of change fell in the distribution of country-level rates of change from 1990 to 2015. We took the mean of these global percentile values across indicators and applied the past rate of change at this mean global percentile to all health-related SDG indicators, irrespective of target definition, to estimate the equivalent 2030 global average value and percentage change from 2015 to 2030 for each indicator. Findings: The global median health-related SDG index in 2017 was 59·4 (IQR 35·4–67·3), ranging from a low of 11·6 (95% uncertainty interval 9·6–14·0) to a high of 84·9 (83·1–86·7). SDG index values in countries assessed at the subnational level varied substantially, particularly in China and India, although scores in Japan and the UK were more homogeneous. Indicators also varied by SDI quintile and sex, with males having worse outcomes than females for non-communicable disease (NCD) mortality, alcohol use, and smoking, among others. Most countries were projected to have a higher health-related SDG index in 2030 than in 2017, while country-level probabilities of attainment by 2030 varied widely by indicator. Under-5 mortality, neonatal mortality, maternal mortality ratio, and malaria indicators had the most countries with at least 95% probability of target attainment. Other indicators, including NCD mortality and suicide mortality, had no countries projected to meet corresponding SDG targets on the basis of projected mean values for 2030 but showed some probability of attainment by 2030. For some indicators, including child malnutrition, several infectious diseases, and most violence measures, the annualised rates of change required to meet SDG targets far exceeded the pace of progress achieved by any country in the recent past. We found that applying the mean global annualised rate of change to indicators without defined targets would equate to about 19% and 22% reductions in global smoking and alcohol consumption, respectively; a 47% decline in adolescent birth rates; and a more than 85% increase in health worker density per 1000 population by 2030. Interpretation: The GBD study offers a unique, robust platform for monitoring the health-related SDGs across demographic and geographic dimensions. Our findings underscore the importance of increased collection and analysis of disaggregated data and highlight where more deliberate design or targeting of interventions could accelerate progress in attaining the SDGs. Current projections show that many health-related SDG indicators, NCDs, NCD-related risks, and violence-related indicators will require a concerted shift away from what might have driven past gains—curative interventions in the case of NCDs—towards multisectoral, prevention-oriented policy action and investments to achieve SDG aims. Notably, several targets, if they are to be met by 2030, demand a pace of progress that no country has achieved in the recent past. The future is fundamentally uncertain, and no model can fully predict what breakthroughs or events might alter the course of the SDGs. What is clear is that our actions—or inaction—today will ultimately dictate how close the world, collectively, can get to leaving no one behind by 2030.
|
|
| 4. |
- Luo, Yiqi, et al.
(författare)
-
Toward more realistic projections of soil carbon dynamics by Earth system models
- 2016
-
Ingår i: Global Biogeochemical Cycles. - 0886-6236. ; 30:1, s. 40-56
-
Tidskriftsartikel (refereegranskat)abstract
- Soil carbon (C) is a critical component of Earth system models (ESMs), and its diverse representations are a major source of the large spread across models in the terrestrial C sink from the third to fifth assessment reports of the Intergovernmental Panel on Climate Change (IPCC). Improving soil C projections is of a high priority for Earth system modeling in the future IPCC and other assessments. To achieve this goal, we suggest that (1) model structures should reflect real-world processes, (2) parameters should be calibrated to match model outputs with observations, and (3) external forcing variables should accurately prescribe the environmental conditions that soils experience. First, most soil C cycle models simulate C input from litter production and C release through decomposition. The latter process has traditionally been represented by first-order decay functions, regulated primarily by temperature, moisture, litter quality, and soil texture. While this formulation well captures macroscopic soil organic C (SOC) dynamics, better understanding is needed of their underlying mechanisms as related to microbial processes, depth-dependent environmental controls, and other processes that strongly affect soil C dynamics. Second, incomplete use of observations in model parameterization is a major cause of bias in soil C projections from ESMs. Optimal parameter calibration with both pool- and flux-based data sets through data assimilation is among the highest priorities for near-term research to reduce biases among ESMs. Third, external variables are represented inconsistently among ESMs, leading to differences in modeled soil C dynamics. We recommend the implementation of traceability analyses to identify how external variables and model parameterizations influence SOC dynamics in different ESMs. Overall, projections of the terrestrial C sink can be substantially improved when reliable data sets are available to select the most representative model structure, constrain parameters, and prescribe forcing fields.
|
|
| 5. |
- Zhang, Tianmeng, et al.
(författare)
-
Observations of a Fast-expanding and UV-bright Type Ia Supernova SN 2013gs
- 2019
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 872:1
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present extensive optical and ultraviolet (UV) observations of the type Ia supernova (SN Ia) 2013gs discovered during the Tsinghua-NAOC Transient Survey. The photometric observations in the optical show that the light curves of SN 2013gs are similar to those of normal SNe Ia, with an absolute peak magnitude of M-B = -19.25 +/- 0.15 mag and a post-maximum decline rate Delta m(15)(B) = 1.00 +/- 0.05 mag. Gehrels Swift Ultr-Violet/Optical Telescope observations indicate that SN 2013gs shows unusually strong UV emission (especially in the uvw1 band) at around the maximum light (M-uvw1 similar to -18.9 mag). The SN is characterized by relatively weak Fe II III absorptions at similar to 5000 angstrom in the early spectra and a larger expansion velocity (v(Si) similar to 13,000 km s(-1) around the maximum light) than the normal-velocity SNe Ia. We discuss the relation between the uvw1 - v color and some observables, including Si II velocity, line strength of Si II lambda 6355 and Fe II/III lines, and Delta m(15)(B). Compared to other fast-expanding SNe Ia, SN 2013gs exhibits Si and Fe absorption lines with similar strength and bluer uvw1 - v color. We briefly discussed the origin of the observed UV dispersion of SNe Ia.
|
|
| 6. |
- Zhou, Ke, et al.
(författare)
-
pi-pi Stacking Distance and Phase Separation Controlled Efficiency in Stable All-Polymer Solar Cells
- 2019
-
Ingår i: Polymers. - : MDPI. - 2073-4360. ; 11:10
-
Tidskriftsartikel (refereegranskat)abstract
- The morphology of the active layer plays a crucial role in determining device performance and stability for organic solar cells. All-polymer solar cells (All-PSCs), showing robust and stable morphologies, have been proven to give better thermal stability than their fullerene counterparts. However, outstanding thermal stability is not always the case for polymer blends, and the limiting factors responsible for the poor thermal stability in some All-PSCs, and how to obtain higher efficiency without losing stability, still remain unclear. By studying the morphology of poly [2,3-bis (3-octyloxyphenyl) quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl](TQ1)/poly[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b ]dithiophene-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl]] (PCE10)/PNDI-T10 blend systems, we found that the rearranged molecular packing structure and phase separation were mainly responsible for the poor thermal stability in devices containing PCE10. The TQ1/PNDI-T10 devices exhibited an improved PCE with a decreased pi-pi stacking distance after thermal annealing; PCE10/PNDI-T10 devices showed a better pristine PCE, however, thermal annealing induced the increased pi-pi stacking distance and thus inferior hole conductivity, leading to a decreased PCE. Thus, a maximum PCE could be achieved in a TQ1/PCE10/PNDI-T10 (1/1/1) ternary system after thermal annealing resulting from their favorable molecular interaction and the trade-off of molecular packing structure variations between TQ1 and PCE10. This indicates that a route to efficient and thermal stable All-PSCs can be achieved in a ternary blend by using material with excellent pristine efficiency, combined with another material showing improved efficiency under thermal annealing.
|
|
| 7. |
- Alkadir Abdulahi, Birhan, 1985, et al.
(författare)
-
Open-Circuit Voltage Modulations on All-Polymer Solar Cells by Side Chain Engineering on 4,8-Di(thiophen-2-yl)benzo[1,2- b:4,5- b′]dithiophene-Based Donor Polymers
- 2018
-
Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 1:6, s. 2918-2926
-
Tidskriftsartikel (refereegranskat)abstract
- In recent years, all-polymer solar cells (all-PSCs), incorporating active layers based on blends of electron-donor (D) and acceptor (A) polymers, have drawn attention because of the advantages they hold in the flexibility of choosing the D:A combinations to modulate their energy levels and to improve their overall open-circuit voltages (V oc ) and power conversion efficiencies (PCE)s. V oc is one of the key parameters for the determination of the PCEs of PSCs. In this work, we synthesized six donor polymers with three different side chains appended to the 4,8-di(thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene (BDT) units. By substituting carbon with sulfur and silicon atoms at the 5-position of the thiophenes attached to the BDT units, the highest occupied molecular orbital (HOMO) levels of the donor polymers could be successfully lowered. As anticipated, the V oc values of the resulting all-PSCs increased along with the lowering of the HOMO levels of the donor polymers. Among the six all-PSCs, the PBDT-BDD:PNDI-T10 all-PSC realized a balance between the photovoltage and photocurrent, where a decent PCE of 5.6% was obtained with a V oc of 0.9 V and a photocurrent of 10.5 mA/cm 2 .
|
|
| 8. |
- Bao, Xiaofeng, et al.
(författare)
-
Benzylidene acylhydrazides inhibit chlamydial growth in a type III secretion- and iron chelation-independent manner
- 2014
-
Ingår i: Journal of Bacteriology. - : American Society for Microbiology. - 0021-9193 .- 1098-5530. ; 196:16, s. 2989-3001
-
Tidskriftsartikel (refereegranskat)abstract
- Chlamydiae are widespread Gram-negative pathogens of humans and animals. Salicylidene acylhydrazides, developed as inhibitors of type III secretion system (T3SS) in Yersinia spp., have an inhibitory effect on chlamydial infection. However, these inhibitors also have the capacity to chelate iron, and it is possible that their antichlamydial effects are caused by iron starvation. Therefore, we have explored the modification of salicylidene acylhydrazides with the goal to uncouple the antichlamydial effect from iron starvation. We discovered that benzylidene acylhydrazides, which cannot chelate iron, inhibit chlamydial growth. Biochemical and genetic analyses suggest that the derivative compounds inhibit chlamydiae through a T3SS-independent mechanism. Four single nucleotide polymorphisms were identified in a Chlamydia muridarum variant resistant to benzylidene acylhydrazides, but it may be necessary to segregate the mutations to differentiate their roles in the resistance phenotype. Benzylidene acylhydrazides are well tolerated by host cells and probiotic vaginal Lactobacillus species and are therefore of potential therapeutic value.
|
|
| 9. |
- Benavides, Cindy Montenegro, et al.
(författare)
-
High-Performance Organic Photodetectors from a High-Bandgap Indacenodithiophene-Based π-Conjugated Donor-Acceptor Polymer
- 2018
-
Ingår i: ACS Applied Materials & Interfaces. - : American Chemical Society (ACS). - 1944-8252 .- 1944-8244. ; 10:15, s. 12937-12946
-
Tidskriftsartikel (refereegranskat)abstract
- A conjugated donor-acceptor polymer, poly[4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-s-indaceno[1,2-b:5,6-b′]dithiophene-2,7-diyl-alt-5-(2-ethylhexyl)-4H-thieno[3,4-c] pyrrole-4,6(5H)-dione-1,3-diyl] (PIDT-TPD), is blended with the fullerene derivative [6,6] phenyl-C61-butyric acid methyl ester (PC 61 BM) for the fabrication of thin and solution-processed organic photodetectors (OPDs). Systematic screening of the concentration ratio of the blend and the molecular weight of the polymer is performed to optimize the active layer morphology and the OPD performance. The device comprising a medium molecular weight polymer (27.0 kg/mol) in a PIDT-TPD:PC 61 BM 1:1 ratio exhibits an external quantum efficiency of 52% at 610 nm, a dark current density of 1 nA/cm 2 , a detectivity of 1.44 × 10 13 Jones, and a maximum 3 dB cutoff frequency of 100 kHz at -5 V bias. These results are remarkable among the state-of-the-art red photodetectors based on conjugated polymers. As such, this work presents a functional organic active material for high-speed OPDs with a linear photoresponse at different light intensities.
|
|
| 10. |
- Bergenti, Ilaria, et al.
(författare)
-
Highly Ordered Organic Ferroelectric DIPAB-Patterned Thin Films
- 2017
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 1520-5827 .- 0743-7463. ; 33:45, s. 12859-12864
-
Tidskriftsartikel (refereegranskat)abstract
- Ferroelectric molecular compounds present great advantages for application in electronics because they combine high polarization values, comparable to those of inorganic materials, with the flexibility and low-cost properties of organic ones. However, some limitations to their applicability are related to the high crystallinity required to deploy ferroelectricity. In this article, highly ordered ferroelectric patterned thin films of diisopropylammonium bromide have been successfully fabricated by a lithographically controlled wetting technique. Confinement favors the self-organization of ferroelectric crystals, avoiding the formation of polymorphs and promoting the long-range orientation of crystallographic axes. Patterned structures present high stability, and the polarization can be switched to be arranged in stable domain pattern for application in devices.
|
|
| 11. |
- Bini, Kim, 1987, et al.
(författare)
-
Alcohol-Soluble Conjugated Polymers as Cathode Interlayers for All-Polymer Solar Cells
- 2018
-
Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 1:5, s. 2176-2182
-
Tidskriftsartikel (refereegranskat)abstract
- Conjugated polymers with polar side-chain components have successfully been used as cathode interfacial materials (CIMs) to improve the performances of polymer solar cells with fullerenes as acceptors. However, their uses and functions in all-polymer solar cells (all-PSCs) have not been well-investigated. Therefore, in this work, four conjugated polymers bearing different functional side chains, including dimethylamine, diethanolamine, and imidazole, were used as CIMs to study their effects on all-PSCs. With a combination of high-performing acceptor and donor polymers as active layers, the performances of the devices based on the four CIMs were compared with conventional devices with LiF/Al and Al as cathode. Compared to the devices with only Al as cathode, the devices comprising conjugated polymers as CIMs presented large improvement in power conversion efficiency from 2.7% to around 5.3%, which is comparable to the devices with LiF/Al as cathode. The encouraging results demonstrated that the use of conjugated interfacial polymers is a robust way to improve the performances of all-PSCs and can elegantly circumvent the use of low work function metals as cathodes. This is very important for roll-to-roll processing of flexible and large-scale solar cells.
|
|
| 12. |
- Bini, Kim, 1987, et al.
(författare)
-
Synthesis and Characterization of Isoindigo-Based Polymers with Thermocleavable Side Chains
- 2018
-
Ingår i: Macromolecular Chemistry and Physics. - : Wiley. - 1022-1352 .- 1521-3935. ; 219:7
-
Tidskriftsartikel (refereegranskat)abstract
- Stability of bulk heterojunction films for organic solar cells is a critical factor for commercial viability. One method to stabilize these films is to include cleavable side chains, which reduce the solubility of the polymers when removed. In order to study the stabilizing effect of cleavable side chains, a series of random copolymers using isoindigo with 0, 10, 20, 50, and 100% thermally cleavable side chains based on the tert-butyloxycarbonyl (t-BOC) group are synthesized. The polymers show a distinct one-step thermal cleavage of the side chains, with no separable dealkylation and decarboxylation steps. The thermal stability in film is studied with transmission electron microscopy and atomic force microscopy. The polymer with all t-BOC side chains on isoindigo significantly improves thermal stability with regard to crystal growth and phase separation in film. These results suggest BOC-substitution can be used for large scale processing to produce insoluble polymer films with a high degree of thermal stability.
|
|
| 13. |
- Bo, Lin, et al.
(författare)
-
Bearing Fault Diagnosis Based on Subband Time-Frequency Texture Tensor
- 2019
-
Ingår i: IEEE Access. - : IEEE. - 2169-3536. ; 7, s. 37611-37619
-
Tidskriftsartikel (refereegranskat)abstract
- The texture feature tensor established from a subband time–frequency image (TFI) was extracted and used to identify the fault states of a rolling bearing. The TFI of adaptive optimal-kernel distribution was optimally partitioned into TFI blocks based on the minimum frequency band entropy. The texture features were extracted from the co-occurrence matrix of each TFI block. Based on the order of the segmented frequency bands, the texture feature tensor was constructed using the multidimensional feature vectors from all the blocks; this preserved the inherent characteristic of the TFI structure and avoided the information loss caused by vectorizing multidimensional features. The linear support higher order tensor machine based on the feature tensor was applied to identify the fault states of the rolling bearing.
|
|
| 14. |
- Cai, C. S., et al.
(författare)
-
Polymer solar cells spray coated with non-halogenated solvents
- 2017
-
Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248. ; 161, s. 52-61
-
Tidskriftsartikel (refereegranskat)abstract
- Using spray-coating technique, we successfully fabricated conventional ITO-based and inverted ITO-free polymer solar cells (PSCs) based on a conjugated polymer poly[2,3-bis-(3-octyloxyphenyl) quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (TQ1) as the donor and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) or [6,6] -phenyl-C71-butyric acid methyl ester (PC71BM) as the acceptor. Environment-friendly non-halogenated solvents were used to process the active layers. The influence of substrate temperatures and processing solvents on the photovoltaic performance of the ITO-based TQ1:PC61BM PSCs was systemically investigated. A higher substrate temperature can accelerate the solvent evaporating rate and afford a micro-textured rougher surface, which efficiently reduced light reflectance and enhanced absorption. Furthermore, finer phase separation was observed when using this high substrate temperature, which led to enhanced photocurrent due to the reduced bimolecular recombination. The device performance of spray-processed PSCs using the non-halogenated solvent mixtures was comparable to that of spray-processed PSCs using the halogenated o-dichlorobenzene (oDCB), which demonstrates that the non-halogenated solvents are very promising in spray-processed PSCs. This work sheds new light on developing efficient roll-to-roll compatible spray-coated PSCs with environment-friendly solvents.
|
|
| 15. |
- Cai, P., et al.
(författare)
-
Effects of including electron-withdrawing atoms on the physical and photovoltaic properties of indacenodithieno 3,2-b thiophene-based donor-acceptor polymers: towards an acceptor design for efficient polymer solar cells
- 2017
-
Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 7:33, s. 20440-20450
-
Tidskriftsartikel (refereegranskat)abstract
- Three new D-A polymers PIDTT-DTBO, PIDTT-DTBT and PIDTT-DTFBT, using indacenodithieno[3,2-b] thiophene (IDTT) as the electron-rich unit and benzoxadiazole (BO), benzodiathiazole (BT) or difluorobenzothiadiazole (FBT) as the electron-deficient unit, were synthesized via a Pd-catalyzed Stille polymerization. The included electron-withdrawing atoms of the acceptor portion were varied between O, S, and F for tailoring the optical and electrochemical properties and the geometry of structures. Their effects on the film topography, photovoltaic and hole-transporting properties of the polymers were thoroughly investigated via a range of techniques. As expected, the stronger electron-withdrawing BO unit affords red-shifted absorption, low-lying HOMO and LUMO levels for the polymer PIDTT-DTBO. However, it depicts lower hole mobility and a less efficient charge collection in the active layer compared to the polymer PIDTT-DTBT. In addition, degradation of the solubility is observed in the fluorinated polymer PIDTT-DTFBT. As a result, a BHJ PSC (ITO/PEDOT: PSS/polymer: PC71BM/interlayer/ Al) fabricated with PIDTT-DTBT attains the best power conversion efficiency (PCE) of 4.91%. These results thus demonstrate the potential effects of electronegative atoms on IDTT-based polymers and the structure-function correlations of such electron-donor materials for efficient PSCs.
|
|
| 16. |
- Chen, W., et al.
(författare)
-
Enhanced efficiency of polymer solar cells by improving molecular aggregation and broadening the absorption spectra
- 2019
-
Ingår i: Dyes and Pigments. - : Elsevier BV. - 0143-7208 .- 1873-3743. ; 166, s. 42-48
-
Tidskriftsartikel (refereegranskat)abstract
- Alkylthio-substituted thiophene-based benzo[1,2-b:4,5-b’]dithiophene (BDT) was used to construct PBDTS-DTBT, a medium band gap donor-acceptor (D-A) polymer with 5,6-difluoro-4,7-bis[4-(2-octyldodecyl)thiophene-2-yl]benzo[c] [1,2,5]thiadiazole (DTBT). The incorporation of sulfur atoms into the side chains not only lowered the highest occupied molecular orbital (HOMO) energy level but also improved molecular aggregation and thus afforded lower band gap (1.68 eV) with full width at half maximum (FWHM) of 170 nm in comparison to that of the analogous polymer (PBDT-DTBT) without sulfur atoms in side chains. Therefore, the bulk heterojunction polymer solar cells based on PBDTS-DTBT with 2% diiodooctane (DIO) as processing additive showed a high power conversion efficiency (PCE) of 9.73% with high open-circuit voltage (V OC , 0.93 V), large short-circuit current density (J SC , 14.23 mA/cm 2 ) and high fill factor (FF, 0.735).
|
|
| 17. |
- Chen, Wen, 1988, et al.
(författare)
-
VLBI Astrometry of radio stars to link radio and optical celestial reference frames. I. HD 199178 & AR Lacertae
- 2023
-
Ingår i: Monthly Notices of the Royal Astronomical Society. - 0035-8711 .- 1365-2966. ; 524:4, s. 5357-5367
-
Tidskriftsartikel (refereegranskat)abstract
- To accurately link the radio and optical Celestial Reference Frames (CRFs) at optical bright end, i.e. with GaiaG-band magnitude ≾13, increasing number and improving sky distribution of radio stars with accurate astrometric parameters from both Very Long Baseline Interferometry (VLBI) and Gaia measurements are mandatory. We selected two radio stars HD 199178 and AR Lacertae as the target for a pilot program for the frame link, using the Very Long Baseline Array at 15 GHz at six epochs spanning about 1 yr, to measure their astrometric parameters. The measured parallax of HD 199178 is 8.949 ± 0.059 mas and the proper motion is μαcos δ = 26.393 ± 0.093 and μδ = −0.950 ± 0.083 mas yr−1, while the parallax of AR Lac is 23.459 ± 0.094 mas and the proper motion is μαcos δ = −51.906 ± 0.138 and μδ = 46.732 ± 0.131 mas yr−1. Our VLBI measured astrometric parameters have accuracies about 4–5 times better than the corresponding historic VLBI measurements and comparable accuracies with those from Gaia, validating the feasibility of frame link using radio stars. With the updated astrometric parameters for these two stars, there is a ∼25 per cent reduction of the uncertainties on the Y-axis for both orientation and spin parameters.
|
|
| 18. |
- Chen, Xin, 1980, et al.
(författare)
-
Improved resource allocation strategy in SU-CoMP network
- 2011
-
Ingår i: The Journal of China Universities of Posts and Telecommunications. - 2210-5123. ; 18:4, s. 7-12
-
Tidskriftsartikel (refereegranskat)abstract
- Coordinated Multi-Point transmission and reception (CoMP) for single user, named as SU-CoMP, is considered as an efficient approach tomitigate inter-cell interference in Orthogonal Frequency Division Multiple Access (OFDMA) systems. Two prevalent approaches in SU-CoMP areCoordinated Scheduling (CS) and Joint Processing (JP). Although JP in SU-CoMP has been proved to achieve a great link performanceimprovement for the cell-edge user, efficient Resource Allocation (RA) on the system level is quite needed. However, so far limited work has beendone considering JP, and most existing schemes achieved the improvement of cell-edge performance at cost of the cell-average performancedegradation compared to the single cell RA. In this paper, a two-phase strategy is proposed for SU-CoMP networks. CS and JP are combined toimprove both cell-edge and cell-average performance. Compared to the single cell RA, simulation results demonstrate that, the proposed strategyleads to both higher cell-average and cell-edge throughput.
|
|
| 19. |
- Chen, Xin, 1980, et al.
(författare)
-
Optimal and Efficient Power Allocation for OFDM Non-Coherent Cooperative Transmission
- 2012
-
Ingår i: IEEE Wireless Communications and Networking Conference, WCNC. - 1525-3511. - 9781467304375 ; , s. 1584-1589
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we study the subchannel (SC) power allocation for orthogonal frequency division multiplexing (OFDM) multiple access points (APs) systems with non-coherent cooperative transmission. The objective is to maximize the total capacity under per-AP power constraints. It can be proved that the optimal solution can be obtained by the combination of an optimal SC partition search and the power allocation across SCs for each feasible partition. Existing work exhaustively searched the optimal SC partition and used Lagrange dual method to compute the power allocation across SCs. Since the entire complexity increases exponentially with the number of SCs, the existing method is unsuitable for practical implementation. In this paper, we propose a novel optimal power allocation algorithm for non-coherent cooperative transmission with a much lower complexity. Firstly, a concept of “cut-off SC” is proposed for searching the optimal SC partition. Then, an efficient optimal power allocation algorithm across SCs is proposed for any given cut-off SC. Simulation results demonstrate that the proposed algorithm is optimal with a polynomial complexity, and ends within an acceptable number of iterations.
|
|
| 20. |
- de las Fuentes, Lisa, et al.
(författare)
-
Gene-educational attainment interactions in a multi-ancestry genome-wide meta-analysis identify novel blood pressure loci
- 2021
-
Ingår i: Molecular Psychiatry. - : Springer Nature. - 1359-4184 .- 1476-5578. ; 26:6, s. 2111-2125
-
Tidskriftsartikel (refereegranskat)abstract
- Educational attainment is widely used as a surrogate for socioeconomic status (SES). Low SES is a risk factor for hypertension and high blood pressure (BP). To identify novel BP loci, we performed multi-ancestry meta-analyses accounting for gene-educational attainment interactions using two variables, “Some College” (yes/no) and “Graduated College” (yes/no). Interactions were evaluated using both a 1 degree of freedom (DF) interaction term and a 2DF joint test of genetic and interaction effects. Analyses were performed for systolic BP, diastolic BP, mean arterial pressure, and pulse pressure. We pursued genome-wide interrogation in Stage 1 studies (N = 117 438) and follow-up on promising variants in Stage 2 studies (N = 293 787) in five ancestry groups. Through combined meta-analyses of Stages 1 and 2, we identified 84 known and 18 novel BP loci at genome-wide significance level (P < 5 × 10-8). Two novel loci were identified based on the 1DF test of interaction with educational attainment, while the remaining 16 loci were identified through the 2DF joint test of genetic and interaction effects. Ten novel loci were identified in individuals of African ancestry. Several novel loci show strong biological plausibility since they involve physiologic systems implicated in BP regulation. They include genes involved in the central nervous system-adrenal signaling axis (ZDHHC17, CADPS, PIK3C2G), vascular structure and function (GNB3, CDON), and renal function (HAS2 and HAS2-AS1, SLIT3). Collectively, these findings suggest a role of educational attainment or SES in further dissection of the genetic architecture of BP.
|
|
| 21. |
- de Vries, Paul S., et al.
(författare)
-
Multiancestry Genome-Wide Association Study of Lipid Levels Incorporating Gene-Alcohol Interactions
- 2019
-
Ingår i: American Journal of Epidemiology. - : Oxford University Press. - 0002-9262 .- 1476-6256. ; 188:6, s. 1033-1054
-
Tidskriftsartikel (refereegranskat)abstract
- A person's lipid profile is influenced by genetic variants and alcohol consumption, but the contribution of interactions between these exposures has not been studied. We therefore incorporated gene-alcohol interactions into a multiancestry genome-wide association study of levels of high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides. We included 45 studies in stage 1 (genome-wide discovery) and 66 studies in stage 2 (focused follow-up), for a total of 394,584 individuals from 5 ancestry groups. Analyses covered the period July 2014-November 2017. Genetic main effects and interaction effects were jointly assessed by means of a 2-degrees-of-freedom (df) test, and a 1-df test was used to assess the interaction effects alone. Variants at 495 loci were at least suggestively associated (P < 1 x 10(-6)) with lipid levels in stage 1 and were evaluated in stage 2, followed by combined analyses of stage 1 and stage 2. In the combined analysis of stages 1 and 2, a total of 147 independent loci were associated with lipid levels at P < 5 x 10(-8) using 2-df tests, of which 18 were novel. No genome-wide-significant associations were found testing the interaction effect alone. The novel loci included several genes (proprotein convertase subtilisin/kexin type 5 (PCSK5), vascular endothelial growth factor B (VEGFB), and apolipoprotein B mRNA editing enzyme, catalytic polypeptide 1 (APOBEC1) complementation factor (A1CF)) that have a putative role in lipid metabolism on the basis of existing evidence from cellular and experimental models.
|
|
| 22. |
- Duan, Hongtao, et al.
(författare)
-
Two-Decade Reconstruction of Algal Blooms in China’s Lake Taihu
- 2009
-
Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 43:10, s. 3522-3528
-
Tidskriftsartikel (refereegranskat)abstract
- The algal blooming in the inland lakes has become a critically important issue for its impacts not only on local natural and social environments, but also on global human community. However, the occurrences of blooming on larger spatial scale and longer time scale have rarely been studied. As the third largest freshwater lake in China, Lake Taihu has drawn increasing attention from both public and scientific communities concerning its degradation. Using available satellite images, we reconstructed the spatial and temporal patterns of algal blooms in Lake Taihu through the past two decades. The blooming characteristics over the past two decades were examined with the dynamic of initial blooming date being highlighted. The initial blooming dates were gradually becoming later and later from 1987 to 1997. Since 1998, however, the initial blooming date came earlier and earlier year by year, with approximately 11.42 days advancement per year. From 1987 to 2007, the annual duration of algal blooms lengthened year by year, in line with the substantial increases in the occurrences of algal blooms in spring and summer months. The algal blooms usually occur in northern bays and spread to center and south parts of Lake Taihu. The increases in previous winter’s mean daily minimum temperature partially contributed to the earlier blooming onset. However, human activities, expressed as total gross domestic product (GDP) and population, outweighed the climatic contribution on the initial blooming date and blooming duration. This study may provide insights for the policy makers who try to curb the algal blooming and improve the water quality of inland freshwater lakes.
|
|
| 23. |
- Feigin, Valery L, et al.
(författare)
-
Global, Regional, and Country-Specific Lifetime Risks of Stroke, 1990 and 2016.
- 2018
-
Ingår i: The New England journal of medicine. - 1533-4406 .- 0028-4793. ; 379:25, s. 2429-2437
-
Tidskriftsartikel (refereegranskat)abstract
- The lifetime risk of stroke has been calculated in a limited number of selected populations. We sought to estimate the lifetime risk of stroke at the regional, country, and global level using data from a comprehensive study of the prevalence of major diseases.We used the Global Burden of Disease (GBD) Study 2016 estimates of stroke incidence and the competing risks of death from any cause other than stroke to calculate the cumulative lifetime risks of first stroke, ischemic stroke, or hemorrhagic stroke among adults 25 years of age or older. Estimates of the lifetime risks in the years 1990 and 2016 were compared. Countries were categorized into quintiles of the sociodemographic index (SDI) used in the GBD Study, and the risks were compared across quintiles. Comparisons were made with the use of point estimates and uncertainty intervals representing the 2.5th and 97.5th percentiles around the estimate.The estimated global lifetime risk of stroke from the age of 25 years onward was 24.9% (95% uncertainty interval, 23.5 to 26.2); the risk among men was 24.7% (95% uncertainty interval, 23.3 to 26.0), and the risk among women was 25.1% (95% uncertainty interval, 23.7 to 26.5). The risk of ischemic stroke was 18.3%, and the risk of hemorrhagic stroke was 8.2%. In high-SDI, high-middle-SDI, and low-SDI countries, the estimated lifetime risk of stroke was 23.5%, 31.1% (highest risk), and 13.2% (lowest risk), respectively; the 95% uncertainty intervals did not overlap between these categories. The highest estimated lifetime risks of stroke according to GBD region were in East Asia (38.8%), Central Europe (31.7%), and Eastern Europe (31.6%), and the lowest risk was in eastern sub-Saharan Africa (11.8%). The mean global lifetime risk of stroke increased from 22.8% in 1990 to 24.9% in 2016, a relative increase of 8.9% (95% uncertainty interval, 6.2 to 11.5); the competing risk of death from any cause other than stroke was considered in this calculation.In 2016, the global lifetime risk of stroke from the age of 25 years onward was approximately 25% among both men and women. There was geographic variation in the lifetime risk of stroke, with the highest risks in East Asia, Central Europe, and Eastern Europe. (Funded by the Bill and Melinda Gates Foundation.).
|
|
| 24. |
- Feitosa, Mary F., et al.
(författare)
-
Novel genetic associations for blood pressure identified via gene-alcohol interaction in up to 570K individuals across multiple ancestries
- 2018
-
Ingår i: PLOS ONE. - : Public library science. - 1932-6203. ; 13:6
-
Tidskriftsartikel (refereegranskat)abstract
- Heavy alcohol consumption is an established risk factor for hypertension; the mechanism by which alcohol consumption impact blood pressure (BP) regulation remains unknown. We hypothesized that a genome-wide association study accounting for gene-alcohol consumption interaction for BP might identify additional BP loci and contribute to the understanding of alcohol-related BP regulation. We conducted a large two-stage investigation incorporating joint testing of main genetic effects and single nucleotide variant (SNV)-alcohol consumption interactions. In Stage 1, genome-wide discovery meta-analyses in approximate to 131 K individuals across several ancestry groups yielded 3,514 SNVs (245 loci) with suggestive evidence of association (P <1.0 x 10(-5)). In Stage 2, these SNVs were tested for independent external replication in individuals across multiple ancestries. We identified and replicated (at Bonferroni correction threshold) five novel BP loci (380 SNVs in 21 genes) and 49 previously reported BP loci (2,159 SNVs in 109 genes) in European ancestry, and in multi-ancestry meta-analyses (P < 5.0 x 10(-8)). For African ancestry samples, we detected 18 potentially novel BP loci (P< 5.0 x 10(-8)) in Stage 1 that warrant further replication. Additionally, correlated meta-analysis identified eight novel BP loci (11 genes). Several genes in these loci (e.g., PINX1, GATA4, BLK, FTO and GABBR2 have been previously reported to be associated with alcohol consumption. These findings provide insights into the role of alcohol consumption in the genetic architecture of hypertension.
|
|
| 25. |
- Feng, S. Z., et al.
(författare)
-
Siloxane-Terminated Side Chain Engineering of Acceptor Polymers Leading to Over 7% Power Conversion Efficiencies in All-Polymer Solar Cells
- 2017
-
Ingår i: ACS Macro Letters. - : American Chemical Society (ACS). - 2161-1653. ; 6:11, s. 1310-1314
-
Tidskriftsartikel (refereegranskat)abstract
- To investigate the influence of functional pendent groups on acceptor polymers and photovoltaic properties of all-polymer solar cells (all-PSCs), two novel acceptor polymers containing siloxane-terminated side chains are synthesized and characterized. Increasing the content of siloxane-terminated side chains can reduce pi-pi stacking distance and improve crystalline behavior, yet lead to poorer solubility of the acceptor polymers. By modulating the proper loadings of siloxane-terminated side chains on the acceptor polymers, the PBDB-T:PNDI-Si25 all-PSC attains a maximal power conversion efficiency (PCE) of 7.4% with an outstanding fill factor of 0.68. The results provide, new insights for developing high-performance all-PSCs through functional group engineering on the acceptor polymers, to achieve good solubility, polymer miscibility, and blend morphology.
|
|
