The water and sediment supply to the lower reach and estuary of the Yellow (Huanghe) River have been altered to a very significant degree by the construction of numerous small to large reservoirs and ...the progressive implementation of water and soil conservation measures across the entire drainage basin since the late 1950s, followed by a basin-scale water regulation program since 2002. There is an urgent need to know how progradation of the Yellow River delta (YRD), an area on which people live and farm, has continued and will continue to respond to these controls. This study examines the changing patterns of water and sediment supply to the YRD over the period of 1950–2013 and, using remote sensing, it evaluates the morphological changes of the delta during 1976–2013. Although both water and sediment input to the delta have been described as declining significantly since the mid 1960s, we show that since 2005 the supply of water has remained at around 20billionm3yr−1 and that for sediment at about 0.13billiontyr−1; water input has been even slightly increasing. The dynamics of extension/shrinking and avulsion in river-mouth channels and accretion/erosion of shorelines is an integrated response to the complex variations in both sediment and water supply. This study develops a quantitative relationship between water and sediment supply and the area of land accretion and it predicts the critical condition for land accretion in the YRD. To ensure that delta land will not be lost, care is needed in the future implementation of the basin-scale water regulation program.
•Water and sediment supply to the Yellow River delta have been significantly controlled by dams.•River mouth channel avulses frequently in the Yellow River delta.•Remote sensing is an effective means for studying the morphological changes of deltas.•Shorelines of the Yellow River delta expand/shrink responding to changes in both water and sediment supply.•Sediment supply to the Yellow River delta has been continuously declining.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Formamidinium lead triiodide (HC(NH2)2PbI3 or FAPbI3) is gaining increasing interest in the field of mesoscopic perovskite solar cells (PSCs) for its broader light absorption compared with the more ...widely studied CH3NH3PbI3 (MAPbI3). Because FAPbI3 has two polymorphs (“black” α-FAPbI3 and “yellow” δ-FAPbI3) at ambient temperature, where α-FAPbI3 is the desirable photoactive perovskite phase, it becomes particularly important to suppress the formation of the nonperovskite δ-FAPbI3 for achieving high efficiency in FAPbI3-based mesoscopic PSCs. In this study, we demonstrate that the judicious use of low-volatility additives in the precursor solution assists in the evolution of α-FAPbI3 through the formation of non-δ-FAPbI3 intermediate phases, which then convert to α-FAPbI3 during thermal annealing. The underlying mechanism involved in the additive-modulated evolution of α-FAPbI3 upon mesoporous TiO2 substrates is elucidated, which suggests guidelines for developing protocols for the fabrication efficient FAPbI3-based mesoscopic PSCs.
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IJS, KILJ, NUK, PNG, UL, UM
The discovery and development of new Pb-free perovskite light-absorber materials that are eco-friendly and stable has become an active research area in the field of photovoltaics (PVs). These ...perovskites are being considered for possibly replacing the Pb-based organic-inorganic halide perovskites in state-of-the-art perovskite solar cells. While the recent effort in this area has led to certain progress, some scientific and technological issues still remain unresolved. Here we provide perspectives on the comprehensive understanding of perovskite toxicity/instability, followed by design strategies for new nontoxic, stable perovskites. We also envision unprecedented challenges in the processing of the promising candidate perovskites that bridges materials design and actual devices. Future research in these directions will open up new possibilities in realizing eco-friendly and stable perovskite PVs for real-world applications.
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Solar power is the most abundant and free source of renewable and sustainable energy on Earth. In response to the pressing need to develop efficient, low-cost photovoltaics (PVs) to harness the solar power, perovskite solar cells (PSCs) have recently emerged as a potential distruptive PV technology. However, the state-of-the-art PSCs employ lead-based organic-inorganic halide perovskites as light absorbers, raising concerns regarding their chemical stability and the use of toxic element lead (Pb) that may be released into the environment. Therefore, it is of long-term practical importance to develop eco-friendly, stable, and efficient perovskite materials for future PSCs that can eventually be commercialized. Moreover, discovery and development of these new perovskite materials will have profound implications on a broad range of (opto)electronic applications, including, but not limited to, solar cells, light-emitting devices, lasers, photodetectors, and X-ray imaging.
The discovery and development of efficient Pb-free perovskite light-absorber materials that are eco-friendly and stable has become an active research area in the field of photovoltaics (PVs). Here we provide perspectives on the comprehensive understanding of perovskite toxicity/instability, followed by design strategies for new Pb-free, stable perovskites. Future research in these directions will open up new possibilities in realizing eco-friendly, stable, and efficient perovskite PVs for real-world applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In recent years, greenhouse development has been innovative in agriculture based on information systems guidance with accelerated growth. The IoT provides an intelligent system and remote access ...technologies such as green infrastructure. The usability of information systems for effective training and producing intelligent systems and predictive models in organizational real-time based on machine learning and artificial intelligence (AI). Therefore, a Remote Sensing Assisted Control System (RSCS) has been proposed for improving greenhouse agriculture requirements. This proposed method utilizes artificial intelligence and machine learning technology for the green development potential industry's ability to manage economic resources and increase innovative agriculture product development patterns. Thus, the key preconditions for increasing healthy food choices and promoting local and global organic farmers' potential development are straightforward suggestions for developing an effective marketing strategy. The experimental results RSCS the highest precision ratio of 95.1%, the performance ratio of 96.35%, a data transmission rate of 92.3%, agriculture production ratio of 94.2%, irrigation control ratio of 94.7%, the lowest moisture content ratio of 18.7%, and CO2 emission ratio of 21.5%, compared to other methods.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Both indoor PM2.5 concentrations and its chemical compositions are of great concern to human health. This study was conducted to characterize PM2.5 in three residential homes with different ...HVAC-filter (HVAC: Heating, Ventilating and Air-Conditioning) scenarios and one outdoor environment in terms of mass concentration, heavy metal composition (Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, Hg and Pb), enrichment factors (EFs) and health risk assessment. The results verified that the utilization of HVAC-filter system helped to improve indoor air quality significantly with the mean reductions of mass concentration, heavy metal contents and related health risks of indoor PM2.5–22.1%, 29.1%, and 48.0% of the atmospheric PM2.5 respectively. However, the EFs in the home with HVAC-filter system were the highest among the tested indoor and outdoor air PM2.5 which reminded the potential pollution related to stainless ventilation ducts and particle characteristics (smaller than 2.5 μm). No evident contributions of the independent household floor heating facility were found to the improvement or the deterioration of indoor air quality from the comparative analysis (p > 0.05). Fe, Zn, Ni, and Mn were the main constituents of the metal elements and accounted for more than 80% of the total elements while Cd was the most enriched metal. Smelting furnaces and coal combustion were the main sources of Cr, Ni and As. Health risk assessment indicated that carcinogenic risks of selected metals in all tested homes (1.22 × 10−6 ∼ 3.32 × 10−4) were unacceptable while non-carcinogenic risks were within the safe range.
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•The utilization of HVAC-filter system helps to improve indoor air quality evidently.•Fe, Zn, Ni, and Mn were the main constituents and contributed >80% of heavy metals.•Smelting furnaces and coal combustion were the main sources of Cr, Ni and As.•Cancer risk levels for Cr, As, Ni and Cd exceeded the accepted limits of 10−6.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Significant effort is being devoted to the search for all-inorganic Pb-free halide perovskites (HPs) for photovoltaic applications. However, candidate HPs that combine all the desirable attributes — ...ease of synthesis, favorable bandgaps, outstanding optoelectronic properties, high stability, no toxicity — are extremely rare. Here, we demonstrate experimentally the promise of cesium titanium(IV) bromide (Cs2TiBr6), a part of the Ti-based vacancy-ordered double-perovskite halides family, in perovskite solar cells (PSCs). We show, for the first time, that high-quality Cs2TiBr6 thin films can be prepared through a facile low-temperature vapor-based method. These films exhibit a favorable bandgap of ∼1.8 eV, long and balanced carrier-diffusion lengths exceeding 100 nm, suitable energy levels, and superior intrinsic and environmental stability. The first demonstration of Cs2TiBr6 thin films-based PSCs shows stable efficiency of up to 3.3%. Insights into the Cs2TiBr6 film-formation mechanisms and the PSC device operation are provided, pointing to directions for improving Ti-based PSCs.
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•Fabrication of Cs2TiBr6 halide perovskite thin films is demonstrated for the first time•Cs2TiBr6 thin films have ∼1.8 eV bandgap and balanced carrier-diffusion lengths >100 nm•Cs2TiBr6 thin films are highly stable under environmental (humidity/heat/light) stresses•First ever solar cells using Cs2TiBr6 thin films show a stable efficiency of up to 3.3
Halide perovskites (HPs) have attracted a great deal of attention in the field of photovoltaics (PVs) in recent years. The efficiency of perovskite solar cells (PSCs) has seen an unprecedentedly rapid rise within a short period of time. However, the toxicity of Pb and the volatility of the organic ions in the state-of-the-art HP light absorbers have been recognized as the two major obstacles in the path of PSC development and commercialization. Thus, the search is on for all-inorganic, Pb-free HPs for use in PSCs. In this study, we demonstrate experimentally the promise of a new candidate HP: cesium titanium(IV) bromide, a member of a larger family of Ti-based HPs that are all-inorganic, non-toxic, and contain only earth-abundant elements. The exploration of PSCs based on this new family of HPs is likely to have a lasting impact on the global landscape of environmentally friendly PVs, and these materials may also find use in other promising (opto)electronic applications.
Cesium titanium(IV) halide perovskites (HPs) are promising all-inorganic, Pb-free materials for perovskite solar cells (PSCs). Here we show that high-quality, uniform thin films of Cs2TiBr6 HP can be prepared through a facile low-temperature vapor-based method. These thin films exhibit a favorable bandgap of ∼1.8 eV, long and balanced carrier-diffusion lengths >100 nm, suitable energy levels, and superior intrinsic and environmental stability. The first planar-heterojunction PSCs based on Cs2TiBr6 thin films show a stable efficiency of up to 3.3%.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Organometal-halide perovskite solar cells have greatly improved in just a few years to a power conversion efficiency exceeding 20%. This technology shows unprecedented promise for terawatt-scale ...deployment of solar energy because of its low-cost, solution-based processing and earth-abundant materials. We have studied charge separation and transport in perovskite solar cells-which are the fundamental mechanisms of device operation and critical factors for power output-by determining the junction structure across the device using the nanoelectrical characterization technique of Kelvin probe force microscopy. The distribution of electrical potential across both planar and porous devices demonstrates p-n junction structure at the TiO2/perovskite interfaces and minority-carrier diffusion/drift operation of the devices, rather than the operation mechanism of either an excitonic cell or a p-i-n structure. Combining the potential profiling results with solar cell performance parameters measured on optimized and thickened devices, we find that carrier mobility is a main factor that needs to be improved for further gains in efficiency of the perovskite solar cells.
Bug characteristics in open source software Tan, Lin; Liu, Chen; Li, Zhenmin ...
Empirical software engineering : an international journal,
12/2014, Volume:
19, Issue:
6
Journal Article
Peer reviewed
To design effective tools for detecting and recovering from software failures requires a deep understanding of software bug characteristics. We study software bug characteristics by sampling 2,060 ...real world bugs in three large, representative open-source projects—the Linux kernel, Mozilla, and Apache. We manually study these bugs in three dimensions—root causes, impacts, and components. We further study the correlation between categories in different dimensions, and the trend of different types of bugs. The findings include: (1) semantic bugs are the dominant root cause. As software evolves, semantic bugs increase, while memory-related bugs decrease, calling for more research effort to address semantic bugs; (2) the Linux kernel operating system (OS) has more concurrency bugs than its non-OS counterparts, suggesting more effort into detecting concurrency bugs in operating system code; and (3) reported security bugs are increasing, and the majority of them are caused by semantic bugs, suggesting more support to help developers diagnose and fix security bugs, especially semantic security bugs. In addition, to reduce the manual effort in building bug benchmarks for evaluating bug detection and diagnosis tools, we use machine learning techniques to classify 109,014 bugs automatically.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Innate immunity plays a vital role in protecting plants and animals from pathogen infections. Immunity varies with age in both animals and plants. However, little is known about the ontogeny of plant ...innate immunity during seedling development. We report here that the Arabidopsis (Arabidopsis thaliana) microRNA miR172b regulates the transcription of the immune receptor gene FLAGELLIN-SENSING2 (FLS2) through TARGET OF EAT1 (TOE1) and TOE2, which directly bind to the FLS2 promoter and inhibit its activity. The level of miR172b is very low in the early stage of seedling development but increases over time, which results in decreased TOE1/2 protein accumulation and, consequently, increased FLS2 transcription and the ontogeny of FLS2-mediated immunity during seedling development. Our study reveals a role for the miR172b-TOE1/2 module in regulating plant innate immunity and elucidates a regulatory mechanism underlying the ontogeny of plant innate immunity.
The Warburg effect is one of the main energy metabolism features supporting cancer cell growth. 20(S)-Rg3 exerts anti-tumor effect on ovarian cancer partly by inhibiting the Warburg effect. microRNAs ...are important regulators of the Warburg effect. However, the microRNA regulatory network mediating the anti-Warburg effect of 20(S)-Rg3 was largely unknown.
microRNA deep sequencing was performed to identify the 20(S)-Rg3-influenced microRNAs in SKOV3 ovarian cancer cells. miR-532-3p was overexpressed by mimic532-3p transfection in SKOV3 and A2780 cells or inhibited by inhibitor532-3p transfection in 20(S)-Rg3-treated cells to examine the changes in HK2 and PKM2 expression, glucose consumption, lactate production and cell growth. Dual-luciferase reporter assay was conducted to verify the direct binding of miR-532-3p to HK2. The methylation status in the promoter region of pre-miR-532-3p gene was examined by methylation-specific PCR. Expression changes of key molecules controlling DNA methylation including DNMT1, DNMT3A, DNMT3B, and TET1-3 were examined in 20(S)-Rg3-treated cells. DNMT3A was overexpressed in 20(S)-Rg3-treated cells to examine its influence on miR-532-3p level, HK2 and PKM2 expression, glucose consumption and lactate production.
Deep sequencing results showed that 11 microRNAs were increased and 9 microRNAs were decreased by 20(S)-Rg3 in SKOV3 cells, which were verified by qPCR. More than 2-fold increase of miR-532-3p was found in 20(S)-Rg3-treated SKOV3 cells. Forced expression of miR-532-3p reduced HK2 and PKM2 expression, glucose consumption and lactate production in SKOV3 and A2780 ovarian cancer cells. Inhibition of miR-532-3p antagonized the suppressive effect of 20(S)-Rg3 on HK2 and PKM2 expression, glucose consumption and lactate production in ovarian cancer cells. Dual-luciferase reporter assay showed that miR-532-3p directly suppressed HK2 rather than PKM2. miR-532-3p level was controlled by the methylation in the promoter region of its host gene. 20(S)-Rg3 inhibited DNMT3A expression while exerted insignificant effect on DNMT1, DNMT3B and TET1-3. 20(S)-Rg3 reversed DNMT3A-mediated methylation in the promoter of the host gene of miR-532-3p, and thus elevated miR-532-3p level followed by suppression of HK2 and PKM2 expression, glucose consumption and lactate production.
20(S)-Rg3 modulated microRNAs to exert the anti-tumor effect in ovarian cancer. 20(S)-Rg3 lessened the DNMT3A-mediated methylation and promoted the suppression of miR-532-3p on HK2 to antagonize the Warburg effect of ovarian cancer cells.
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