[Objective] N2Oand NOX(NO, NO2) are important nitrogen oxides gases(NOGs) in paddy fields, and rice plants play important roles in NOG emissions in paddy fields. However, the source of NOG emissions from rice phyl...[Objective] N2Oand NOX(NO, NO2) are important nitrogen oxides gases(NOGs) in paddy fields, and rice plants play important roles in NOG emissions in paddy fields. However, the source of NOG emissions from rice phyllosphere and roots and their relationship to light quality and intensity still remain unclear. In this study, the relationship between light quality, intensity and N2 O, NOX(NO, NO2) emissions from rice phyllosphere and roots at tillering stage was investigated to clarify the contribution of rice plants to N2Oand NOX(NO, NO2) emissions and analyze the mechanism of light control, aiming at providing a scientific basis for revealing how light-control technology affects NOG emissions from rice at tillering stage in paddy fields. [Method] In this study, nitrogen content was controlled by a hydroponic system. A small electric incubator was used for light control. A simultaneous determination was designed to investigate the effect of different weak light qualities(yellow, green, white, red and blue lights) and intensities(dark, 0 lx; very weak, 2 000lx; weak, 4 000 lx; moderate, 6 000 lx; strong, 8 000 lx) on N2Oand NOXemissions from rice phyllosphere and roots at tillering stage in a liquid culture medium system. N2Oconcentration in air samples was determined by gas chromatography within 12 h, and NOX(NO, NO2) concentration was analyzed using 42 i NO- NO2-NOXgas analyzer. [Result] The results showed that:(1) Under a constant nitrogen condition(NH4NO3-N, 90 mg/L) when rice seedlings were treated with moderate(6 000lx) and strong(8 000 lx) light, the average emission rate of N2Oand NO from rice phyllosphere at tillering stage was 27.08, 32.33 μg/(pot·h) and 0.114, 0.057 μg/(pot·h),respectively, accounting for 57.38%, 58.65% and 9.65%, 4.52% of the total release of N2Oand NO from the whole rice plant, respectively. It implicated that rice phyllosphere is an important source of N2Oemission at tillering stage in paddy fields.(2)When rice seedlings were treated with yellow, green, white, red and blue LED lights under a constant light intensity(1 600 lx), the average emission rate of N2Ofrom rice phyllosphere was 6.83, 9.40, 9.73, 2.82 and 4.08 μg/(pot·h), respectively. Compared with green and yellow LED lights, N2Oemission from rice phyllosphere and roots at tillering stage was inhibited markedly by red(3 000 lx) and blue(2 500 lx)LED lights(P0.01). In addition, NO emission from rice phyllosphere was enhanced significantly by white and red LED lights, while NO emissions from rice phyllosphere and roots were inhibited by blue light synchronously. Nevertheless, no evident NO2 emission from rice phyllosphere and roots was detected under the same condition.(3) Within the range of 0-8 000 lx, NO and N2Oemissions from rice roots and N2Oemission from rice phyllosphere increased with the enhancement of light intensity. In contrast, NO emission from rice phyllosphere was inhibited remarkably by moderate(6 000 lx) and strong(8 000 lx) light(P〈 0.01). [Conclusion] Rice seedlings mainly exhibited net emissions of NO2 from the phyllosphere and roots.N2Oand NOX(NO, NO2) emissions from rice phyllosphere and roots at tillering stage could be inhibited by adjusting the composition of visible light(synchronously increasing the proportions of red and blue lights) and appropriately controlling daytime light intensity.展开更多
Escalating apprehension about the harmful effects of widespread use of conventional fossil fuels in the marine field and in internal combustion engines in general, has led to a vast amount of efforts and the directing...Escalating apprehension about the harmful effects of widespread use of conventional fossil fuels in the marine field and in internal combustion engines in general, has led to a vast amount of efforts and the directing of large capital investment towards research and development of sustainable alternative energy sources. One of the most promising and abundant of these sources is hydrogen. Firstly, the use of current fossil fuels is. discussed focusing on the emissions and economic sides to emphasize the need for a new, cleaner and renewable fuel with particular reference to hydrogen as a suitable possible alternative. Hydrogen properties, production and storage methods are then reviewed along with its suitability from the economical point of view. Finally, a cost analysis for the use of hydrogen in internal combustion engines is carried out to illustrate the benefits of its use as a replacement for diesel. The outcome of this cost analysis shows that 98% of the capital expenditure is consumed by the equipment, and 68.3% of the total cost of the equipment is spent on the solar photovoltaic cells. The hydrogen plant is classified as a large investment project because of its high initial cost which is about 1 billion US$; but this is justified because hydrogen is produced in a totally green way. When hydrogen is used as a fuel, no harmful emissions are obtained.展开更多
Two soluble copolymers of fluorenone and dioctoxylbenzene (PFN) or anthracene (PFNAn) were synthesized through Heck polymerization, and were characterized by gel permeation chromatography (GPC), FT-IR, IH-NMR, e...Two soluble copolymers of fluorenone and dioctoxylbenzene (PFN) or anthracene (PFNAn) were synthesized through Heck polymerization, and were characterized by gel permeation chromatography (GPC), FT-IR, IH-NMR, elemental analysis and thermogravimetric analysis. The polymers possess good solubility in common organic solvents and high thermal stability with the Onset decomposition temperature at higher than 410 ℃. The photophysical properties of the polymers were investigated in both solutions and spin-coated films. Cyclic voltammetry results revealed that the copolymers possess higher electron affinity and reversible reduction/re-oxidation processes. Their electroluminescent properties were further investigated. PFN and PFNAn show stable and saturated red light emission with high thermal stability and high electron injection ability. This type of conjugated polymers may be promising for the applications as electron acceptors in polymer photovoltaic cells and electron transporting materials.展开更多
Emissions of biogenic sulfur gases(hydrogen sulfide(H_2S) and carbonyl sulfide(COS)) from Phragmites australis coastal marsh in the Yellow River estuary of China were determined during April to December in 2014 using ...Emissions of biogenic sulfur gases(hydrogen sulfide(H_2S) and carbonyl sulfide(COS)) from Phragmites australis coastal marsh in the Yellow River estuary of China were determined during April to December in 2014 using static chamber-gas chromatography technique with monthly sampling. The results showed that the fluxes of H_2S and COS both had distinct seasonal and diurnal variations. The H_2S fluxes ranged from 0.09 μg/(m^2·h) to 7.65 μg/(m^2·h), and the COS fluxes ranged from –1.10 μg/(m^2·h) to 3.32 μg/(m^2·h). The mean fluxes of H_2S and COS from the P. australis coastal marsh were 2.28 μg/(m^2·h), and 1.05 μg/(m^2·h), respectively. The P. australis coastal marsh was the emission source of both H_2S and COS over the whole year. Fluxes of H_2S and COS were both higher in plant growing season than in the non-growing season. Temperature had a dramatic effect on the H_2S emission flux, while the correlations between COS flux and the environmental factors were not found during sampling periods. More in-depth and comprehensive research on other related factors, such as vegetation, sediment substrates, and tidal action is needed to discover and further understand the key factors and the release mechanism of sulfur gases.展开更多
The rare earth ternary complex of Eu 3+ with thenoyltrifluoroacetone,and 4,7-2NH2 phenanthroline was synthesized and well characterized by UV,fluorescent,IR spectrometry and X-ray diffractometry(XRD)as well as element...The rare earth ternary complex of Eu 3+ with thenoyltrifluoroacetone,and 4,7-2NH2 phenanthroline was synthesized and well characterized by UV,fluorescent,IR spectrometry and X-ray diffractometry(XRD)as well as elemental analysis.The results show that the complex of Eu(III)emits strong red luminescence when excited by UV light,and Eu(TTA)3(2NH2-Phen)has the higher sensitized luminescent efficiency and longer lifetime than Eu(TTA)3(Phen).In device of ITO/PVK/Eu(TTA)3(2NH2-Phen)/Al,the spectra of Eu(TTA)3(2NH2-Phen)with different ratios for spin-cast film were monitored.The main emitting peak at 614 nm can be attributed to the transition of 5 D0→ 7 F2 of Eu 3+ and this process results in the enhancement of red emission from electroluminescence device.The effect and mechanism of the ligands on the luminescence properties of europium complex were discussed.The results show that the luminescence intensity of the title complexes greatly increases in comparison with that of their corresponding complexes,revealing that the second ligands form very good synergistic effect with the first ligands.The title complexes possess excellent thermal stability properties,and are hopefully developed into fine PL and EL red materials.展开更多
Snowmelt is an important component of any snow-fed river system.The Jhelum River is one such transnational mountain river flowing through India and Pakistan.The basin is minimally glacierized and its discharge is larg...Snowmelt is an important component of any snow-fed river system.The Jhelum River is one such transnational mountain river flowing through India and Pakistan.The basin is minimally glacierized and its discharge is largely governed by seasonal snow cover and snowmelt.Therefore,accurate estimation of seasonal snow cover dynamics and snowmeltinduced runoff is important for sustainable water resource management in the region.The present study looks into spatio-temporal variations of snow cover for past decade and stream flow simulation in the Jhelum River basin.Snow cover extent(SCE) was estimated using MODIS(Moderate Resolution Imaging Spectrometer) sensor imageries.Normalized Difference Snow Index(NDSI) algorithm was used to generate multi-temporal time series snow cover maps.The results indicate large variation in snow cover distribution pattern and decreasing trend in different sub-basins of the Jhelum River.The relationship between SCE-temperature,SCE-discharge and discharge-precipitation was analyzed for different seasons and shows strong correlation.For streamflow simulation of the entire Jhelum basin Snow melt Runoff Model(SRM) used.A good correlation was observed between simulated stream flow and in-situ discharge.The monthly discharge contribution from different sub-basins to the total discharge of the Jhelum River was estimated using a modified version of runoff model based on temperature-index approach developed for small watersheds.Stream power - an indicator of the erosive capability of streams was also calculated for different sub-basins.展开更多
Jordan has a good natural potential for solar energy source. To reach at economic practicability of solar energy sources, Jordan needs to accelerate the development of the national photovoltaic projects. The economic ...Jordan has a good natural potential for solar energy source. To reach at economic practicability of solar energy sources, Jordan needs to accelerate the development of the national photovoltaic projects. The economic and financial analysis of the 75 MW Photovoltaic Project for Jordan is presented in this paper. Comparing analysis considers, seven different scenarios regarding the type of the modules and of the mounting system as well as three different cases to further evaluate the effects of land requirements based on an equivalent installed capacity. Based on the analyzed scenarios, it was found that the project will serve as a "fuel saver", as the energy generated at the Jordan Photovoltaic Project replaces energy generated at the thermal plant with the highest variable costs in the grid. This replacement has it, which avoids the CO2 emissions associated with thermal generation, as the further advantage.展开更多
Modification of classic fluorophore to possess the emission transitions between aggregation-induced emission (ALE) and intrinsic emission offers reliable approach to the design of ratiometric fluorescent sensors. In...Modification of classic fluorophore to possess the emission transitions between aggregation-induced emission (ALE) and intrinsic emission offers reliable approach to the design of ratiometric fluorescent sensors. In this study, a proton acceptor benzimidazole was integrated with BODIPY to form three compounds, BBI-1/2/3, which demonstrated the AIE (-595 nm, Iagg) in neutral aqueous medium and intrinsic BODIPY emission (-510 nm,Iint) in acidic medium. All the three showed the ratiometric pH sensing behavior in a dual excitation/dual emission mode, yet BBI-3 displayed still the dual emission ratiometric pH sensing ability. The pH-dependent emission ratio/int/Iagg of the three were fully reversible, and no interference was observed from normal abundant chemical species in live cells. Their different pKa (BBI-1, pKa 4.4; BBI-2, pKa 2.7; BBI-3, pKa 3.6) suggested that the substituents on benzimidazole moiety were essential to govern their functioning pH range. The ratiometric imaging of BBI-1 in A549 cells provided an effective intracellular pH (pHi) calibration formula corresponding to emission ratio oflJ Iint/Iagg. Ratiometric pH imaging in A549 cells upon small particle exposure confirmed the particle-induced cellular acidification with this formula. Both particle size and the chemical nature of the particle contribute to the observed acidification effect. The synchronization of lysosome disruption to cellular acidification in A549 cells upon crystalline silica exposure was directly observed for the first time with BBI-1, showing the potential application of BBI-1 in the study of silicosis and other related diseases. This study de- monstrated that endowing fluorophore with AIE/intrinsic emission transition could be a promising strategy for ratiometric sensor design.展开更多
Molecular materials exhibiting room temperature phosphorescence(RTP) have received much attention during last few years. It has been known that different stacking fashions(e.g., formation of polymorph) and aggregation...Molecular materials exhibiting room temperature phosphorescence(RTP) have received much attention during last few years. It has been known that different stacking fashions(e.g., formation of polymorph) and aggregation/crystal states could largely influence the RTP efficiency. However, whether the crystal morphology or shape could play a key role in modulation of the RTP has not been detected yet. In this work, we report that the dibenzothiophene(DBT) with the same molecular stacking fashion but different crystal morphologies can present alternated RTP performances. By modulation of the fluorescence and phosphorescence dual emission, a direct warm-white color light-emitting has also been successfully achieved. Moreover, the RTP emission can be further tuned through hybridization with β-cyclodextrin in different ratios, with the longest lifetime of 0.43 s.展开更多
ZnO nanorods prepared by a solution-phase method are annealed at different temperatures in oxygen ambient.The luminescence properties of the samples are investigated.In the same excitation condition,the photoluminesce...ZnO nanorods prepared by a solution-phase method are annealed at different temperatures in oxygen ambient.The luminescence properties of the samples are investigated.In the same excitation condition,the photoluminescence(PL) spectra of all samples show an ultraviolet(UV) emission and a broad strong visible emission band.The asymmetric visible emis-sion band of annealed samples has a red-shift as the annealing temperature increasing from 200 ℃ to 600 ℃ and it can be deconvoluted into two subband emissions centered at 535 nm(green emission) and 611 nm(orange-red emission) by Gaussian-fitting analysis.Analyses of PL excitation(PLE) spectra and PL spectra at different excitation wavelengths reveal that the green emission and the orange-red emission have a uniform initial state,which can be attributed to the electron transition from Zn interstitial(Zni) to oxygen vacancy(Vo) and oxygen interstitial(Oi),respectively.展开更多
Mercury is one of the major toxic pollutants and has many adverse effects on human health. The main mercury species in the environment or in living organisms are inorganic mercuric ion (Hg2+) and organic methylmerc...Mercury is one of the major toxic pollutants and has many adverse effects on human health. The main mercury species in the environment or in living organisms are inorganic mercuric ion (Hg2+) and organic methylmercury (CH3Hg+). Detection of the two mercury ions is a particularly active topic in the molecular sensing field during the past decade. However, efficient sensors that can sensitively detect and discriminate the two species are rare. In this work, we adopt the concept of restriction of intramolecular rotations which is the basis of aggregation induced emission, and design a molecular probe with pyridyl group as the chelating unit and 1,8-naphthalimide as the fluorescent unit for the detection of both Hg2+ and CH3Hg+. When the probe is free in solution, it exhibits weak fluorescence because free intramolecular rotations of the 1,8-naphthalimide moieties non-radiatively annihilate its excited state. However, upon coordination with Hg2+ or CH3Hg+, the rotation of 1,8-naphthalimide moieties would be restricted due to the chelation between 1,8-naphthalimide and Hg2+ or CH3Hg+, leading to significantly enhanced fluorescent emission. The response induced by Hg2+ is much stronger than CH3Hg+; but for specific detection of CH3Hg+, we introduced a T-rich DNA fragment which could completely mask Hg2+ in solution. Furthermore, we have employed the sensor for confocal imaging of rig2+ and CH3Hg+in immobilized cells. We expect the probe design tactics can be generally useful for sensing many other analytes.展开更多
Exploration of novel organic luminophores that exhibit thermally activated delayed fluorescence(TADF) in the aggregated state is very crucial for advance of delayed luminescence-based applications such as time-gated b...Exploration of novel organic luminophores that exhibit thermally activated delayed fluorescence(TADF) in the aggregated state is very crucial for advance of delayed luminescence-based applications such as time-gated bio-sensing and temperature sensing.We report herein that synthesis, photophysical properties, molecular and crystal structures, and theoretical calculations of 2,6-bis(diarylamino)benzophenones. Absorption spectra in solution and calculations using density functional theory(DFT) method revealed that the optical excitation took place through intramolecular charge-transfer from one diarylamino moiety to an aroyl group. While the benzophenones did not luminesce in solution, the solids of the benzophenones emitted green light with moderate-to-good quantum yields. Thus, the benzophenones exhibit aggregation-induced emission. Based on the lifetime measurement, the green emission of the solids was found to include TADF. The emergence of the TADF is supported by the small energy gap between the excited singlet and triplet states, which was estimated by time-dependent DFT calculations. Thin films of poly(methyl methacrylate) doped by the benzophenones also showed green prompt and delayed fluorescence whose lifetimes were in the order of microseconds. Linear correlation between logarithm value of TADF lifetime and temperature was observed with the benzophenone in powder, suggesting that the benzophenones can serve as molecular thermometers workable under aqueous conditions.展开更多
Luminescent materials exhibiting emission switching in the solid state have drawn much attention though there is still no clear design strategy for such materials. In this letter, we reported the crystallization induc...Luminescent materials exhibiting emission switching in the solid state have drawn much attention though there is still no clear design strategy for such materials. In this letter, we reported the crystallization induced emission enhancement (CIEE) of di(4-ethoxyphenyl)dibenzofulvene (1), and achieved switching its emission among four different colors through modulation of its molecular packing patterns. We have investigated its potential application as optical recording materials. The twisted conformations of CIEE compounds afford morphology dependent emission and facilitate tuning their emission through modulation of molecular packing patterns. Thus we provide a possible design strategy for solid stimulus responsive luminescent materials.展开更多
A new dual-state emission(DSE) dye comprised of tetraphenylethene(TPE), triphenylamine(TPA), and indoline groups has been synthesized, which showed efficient fluorescence in both solution and solid. The dye is compris...A new dual-state emission(DSE) dye comprised of tetraphenylethene(TPE), triphenylamine(TPA), and indoline groups has been synthesized, which showed efficient fluorescence in both solution and solid. The dye is comprised of three parts and these parts show different fluorescence properties which can be very useful in some applications since the dye can produce information-rich responses. For example, the dye is p H-sensitive in both solution and solid states, and it emits yellow fluorescence in normal p H and red/NIR fluorescence in acidic condition. Cytotoxicity of the dye is low at concentration of 3 μM which was confirmed by a methyl thiazolyl tetrazolium(MTT) experiment, and in vitro experiments revealed that the p H responsive performance can be used in bioimaging. It provides a novel p H-sensitive DSE dye ever reported, which has potential application in many fields.展开更多
Biothiols are important species in physiological processes such as regulating protein structures, redox homeostasis and cell signalling. Alternation in the biothiol levels is associated with various pathological proce...Biothiols are important species in physiological processes such as regulating protein structures, redox homeostasis and cell signalling. Alternation in the biothiol levels is associated with various pathological processes, therefore non-invasive fluorescent probes with high specificity to biothiols are highly desirable research utilities. Meanwhile, fluorescent probes with aggregationinduced emission properties(AIEgens) possess unique photophysical properties that allow modulation of the sensing process through controlling the aggregation-disaggregation or the intramolecular rotational motions of the fluorophores. Herein we review the recent progress in the development of biothiol-specific AIEgens. In particular, the molecular design principles to target different types of biothiols and the corresponding sensing mechanisms are discussed, along with the potential of the future design and development of multi-functional bioprobes.展开更多
Editor's comments Formaldehyde (HCHO) emitted from chemical manufacturing plants including methanol-gasoline/diesel fuel vehicles and the construction and decoration materials is one of the major air pollutions, wh...Editor's comments Formaldehyde (HCHO) emitted from chemical manufacturing plants including methanol-gasoline/diesel fuel vehicles and the construction and decoration materials is one of the major air pollutions, which induces photochemical pollution and hazards human health. Great efforts have been made for the reduction or control of the emission of HCHO to satisfy the stringent environmental regulations. Now, a new study supported by the National Natural Science Foundation of China reports mesoporous manganese oxide with novel nanostructures for the decomposition of HCHO. The obtained manganese oxide nanomaterials showed high catalytic activities for oxidative decomposition of HCHO at low temperatures. Complete conversion of HCHO to CO2 and H2O were achieved, and no harmful by- products were detected in effluent gases. The catalytic activities of these nanomaterials are significantly higher than those of previously reported manganese oxide octahedral molecular sieve (OMS-2) nanorods , MnO x powders, and alumnina-supported mangnaese-palladium oxide catalysts. These results provide a new route for the removal of HCHO and other air pollutions.展开更多
Tetraphenylethene (TPE) is a popular luminogen characterized by aggregation-induced emission and has been widely used to construct solid-state emissive materials. In this work, two thermally stable polymers (P1 and P2...Tetraphenylethene (TPE) is a popular luminogen characterized by aggregation-induced emission and has been widely used to construct solid-state emissive materials. In this work, two thermally stable polymers (P1 and P2) consisting of TPE conjugated to the 2,7-positions of fluorene and carbazole, respectively, are synthesized and characterized. Both polymers are weakly fluorescent in solutions but show greatly enhanced emission as the aggregate formation, presenting an aggregation-enhanced emission feature. Two kinds of polymer light-emitting diodes are fabricated utilizing P1 and P2 as emitters (EML) (device I: ITO/PEDOT:PSS (45 nm)/PVK:EML (1:1 wt%, 55 nm)/TPBI (38 nm)/Ca:Ag; device II: ITO/PEDOT:PSS (45 nm)/ PVK:OXD-7:EML (3:1:3 wt%, 55 nm)/TPBI (38 nm)/Ca:Ag). The device II of P2 shows the best performances, affording a maximum luminance of 6500 cd/m 2 and a high peak efficiency of 2.11 cd/A.展开更多
The aggregation-induced emission(AIE) phenomenon provides a new direction for the development of organic light-emitting devices. Here, we present a new class of emitters based on 4,4-difluoro-4-bora-3 a,4 a-diaza-s-in...The aggregation-induced emission(AIE) phenomenon provides a new direction for the development of organic light-emitting devices. Here, we present a new class of emitters based on 4,4-difluoro-4-bora-3 a,4 a-diaza-s-indacene(BODIPY), functionalized at different positions with tetraphenylethylene(TPE), which is one of the most famous AIE luminogens. Thanks to this modification, we were able to tune the photoluminescence of the BODIPY moiety from the green to the near-infrared(NIR)spectral range and achieve PL efficiencies of ~50% in the solid state. Remarkably, we observed an enhancement of the AIE and up to ~100% photoluminescence efficiencies by blending the TPE-substituted BODIPY fluorophores with a poly[(9,9-di-noctylfluorene-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,7-diyl)](F8 BT) matrix. By incorporating these blends in organic lightemitting diodes(OLEDs), we obtained electroluminescence peaked in the range 650–700 nm with up to 1.8% external quantum efficiency and ~2 m W/cm2 radiance, a remarkable result for red/NIR emitting and solution-processed OLEDs.展开更多
基金Supported by National Natural Science Foundation of China(3116041241361056)+1 种基金General Program of Basic Research of Yunnan Province(2011FZ183)Talent Introduction Project of Kunming University(YJL12012)~~
文摘[Objective] N2Oand NOX(NO, NO2) are important nitrogen oxides gases(NOGs) in paddy fields, and rice plants play important roles in NOG emissions in paddy fields. However, the source of NOG emissions from rice phyllosphere and roots and their relationship to light quality and intensity still remain unclear. In this study, the relationship between light quality, intensity and N2 O, NOX(NO, NO2) emissions from rice phyllosphere and roots at tillering stage was investigated to clarify the contribution of rice plants to N2Oand NOX(NO, NO2) emissions and analyze the mechanism of light control, aiming at providing a scientific basis for revealing how light-control technology affects NOG emissions from rice at tillering stage in paddy fields. [Method] In this study, nitrogen content was controlled by a hydroponic system. A small electric incubator was used for light control. A simultaneous determination was designed to investigate the effect of different weak light qualities(yellow, green, white, red and blue lights) and intensities(dark, 0 lx; very weak, 2 000lx; weak, 4 000 lx; moderate, 6 000 lx; strong, 8 000 lx) on N2Oand NOXemissions from rice phyllosphere and roots at tillering stage in a liquid culture medium system. N2Oconcentration in air samples was determined by gas chromatography within 12 h, and NOX(NO, NO2) concentration was analyzed using 42 i NO- NO2-NOXgas analyzer. [Result] The results showed that:(1) Under a constant nitrogen condition(NH4NO3-N, 90 mg/L) when rice seedlings were treated with moderate(6 000lx) and strong(8 000 lx) light, the average emission rate of N2Oand NO from rice phyllosphere at tillering stage was 27.08, 32.33 μg/(pot·h) and 0.114, 0.057 μg/(pot·h),respectively, accounting for 57.38%, 58.65% and 9.65%, 4.52% of the total release of N2Oand NO from the whole rice plant, respectively. It implicated that rice phyllosphere is an important source of N2Oemission at tillering stage in paddy fields.(2)When rice seedlings were treated with yellow, green, white, red and blue LED lights under a constant light intensity(1 600 lx), the average emission rate of N2Ofrom rice phyllosphere was 6.83, 9.40, 9.73, 2.82 and 4.08 μg/(pot·h), respectively. Compared with green and yellow LED lights, N2Oemission from rice phyllosphere and roots at tillering stage was inhibited markedly by red(3 000 lx) and blue(2 500 lx)LED lights(P0.01). In addition, NO emission from rice phyllosphere was enhanced significantly by white and red LED lights, while NO emissions from rice phyllosphere and roots were inhibited by blue light synchronously. Nevertheless, no evident NO2 emission from rice phyllosphere and roots was detected under the same condition.(3) Within the range of 0-8 000 lx, NO and N2Oemissions from rice roots and N2Oemission from rice phyllosphere increased with the enhancement of light intensity. In contrast, NO emission from rice phyllosphere was inhibited remarkably by moderate(6 000 lx) and strong(8 000 lx) light(P〈 0.01). [Conclusion] Rice seedlings mainly exhibited net emissions of NO2 from the phyllosphere and roots.N2Oand NOX(NO, NO2) emissions from rice phyllosphere and roots at tillering stage could be inhibited by adjusting the composition of visible light(synchronously increasing the proportions of red and blue lights) and appropriately controlling daytime light intensity.
文摘Escalating apprehension about the harmful effects of widespread use of conventional fossil fuels in the marine field and in internal combustion engines in general, has led to a vast amount of efforts and the directing of large capital investment towards research and development of sustainable alternative energy sources. One of the most promising and abundant of these sources is hydrogen. Firstly, the use of current fossil fuels is. discussed focusing on the emissions and economic sides to emphasize the need for a new, cleaner and renewable fuel with particular reference to hydrogen as a suitable possible alternative. Hydrogen properties, production and storage methods are then reviewed along with its suitability from the economical point of view. Finally, a cost analysis for the use of hydrogen in internal combustion engines is carried out to illustrate the benefits of its use as a replacement for diesel. The outcome of this cost analysis shows that 98% of the capital expenditure is consumed by the equipment, and 68.3% of the total cost of the equipment is spent on the solar photovoltaic cells. The hydrogen plant is classified as a large investment project because of its high initial cost which is about 1 billion US$; but this is justified because hydrogen is produced in a totally green way. When hydrogen is used as a fuel, no harmful emissions are obtained.
基金Projects(50803074, 50633050) supported by the National Natural Science Foundation of ChinaProject supported by the Opening Fund of State Key Laboratory of Powder MetallurgyStart-up Fund of Central South University, China
文摘Two soluble copolymers of fluorenone and dioctoxylbenzene (PFN) or anthracene (PFNAn) were synthesized through Heck polymerization, and were characterized by gel permeation chromatography (GPC), FT-IR, IH-NMR, elemental analysis and thermogravimetric analysis. The polymers possess good solubility in common organic solvents and high thermal stability with the Onset decomposition temperature at higher than 410 ℃. The photophysical properties of the polymers were investigated in both solutions and spin-coated films. Cyclic voltammetry results revealed that the copolymers possess higher electron affinity and reversible reduction/re-oxidation processes. Their electroluminescent properties were further investigated. PFN and PFNAn show stable and saturated red light emission with high thermal stability and high electron injection ability. This type of conjugated polymers may be promising for the applications as electron acceptors in polymer photovoltaic cells and electron transporting materials.
基金National Nature Science Foundation of China(No.41103036)Natural Science Foundation of Shandong Province,China(No.BS2009HZ013)
文摘Emissions of biogenic sulfur gases(hydrogen sulfide(H_2S) and carbonyl sulfide(COS)) from Phragmites australis coastal marsh in the Yellow River estuary of China were determined during April to December in 2014 using static chamber-gas chromatography technique with monthly sampling. The results showed that the fluxes of H_2S and COS both had distinct seasonal and diurnal variations. The H_2S fluxes ranged from 0.09 μg/(m^2·h) to 7.65 μg/(m^2·h), and the COS fluxes ranged from –1.10 μg/(m^2·h) to 3.32 μg/(m^2·h). The mean fluxes of H_2S and COS from the P. australis coastal marsh were 2.28 μg/(m^2·h), and 1.05 μg/(m^2·h), respectively. The P. australis coastal marsh was the emission source of both H_2S and COS over the whole year. Fluxes of H_2S and COS were both higher in plant growing season than in the non-growing season. Temperature had a dramatic effect on the H_2S emission flux, while the correlations between COS flux and the environmental factors were not found during sampling periods. More in-depth and comprehensive research on other related factors, such as vegetation, sediment substrates, and tidal action is needed to discover and further understand the key factors and the release mechanism of sulfur gases.
基金Project(B201015)supported by the Natural Science Foundation of Heilongjiang Province,ChinaProject(11551482)supported by the Scientific and Technical Research Project of Education Department of Heilongjiang Province,China+3 种基金Projects(L2010-124,L2010-144)supported by the Research Fund for Jiamusi University,ChinaProject(E08050204)supported by the Research Fund for the Provincial Key Laboratory of Biomaterials Jiamusi University,ChinaProject(2009-360)supported by Health Commission of Heilongjiang Province,ChinaProject supported by Key Laboratory of Luminescence and Optical Information,Beijing Jiaotong University,China
文摘The rare earth ternary complex of Eu 3+ with thenoyltrifluoroacetone,and 4,7-2NH2 phenanthroline was synthesized and well characterized by UV,fluorescent,IR spectrometry and X-ray diffractometry(XRD)as well as elemental analysis.The results show that the complex of Eu(III)emits strong red luminescence when excited by UV light,and Eu(TTA)3(2NH2-Phen)has the higher sensitized luminescent efficiency and longer lifetime than Eu(TTA)3(Phen).In device of ITO/PVK/Eu(TTA)3(2NH2-Phen)/Al,the spectra of Eu(TTA)3(2NH2-Phen)with different ratios for spin-cast film were monitored.The main emitting peak at 614 nm can be attributed to the transition of 5 D0→ 7 F2 of Eu 3+ and this process results in the enhancement of red emission from electroluminescence device.The effect and mechanism of the ligands on the luminescence properties of europium complex were discussed.The results show that the luminescence intensity of the title complexes greatly increases in comparison with that of their corresponding complexes,revealing that the second ligands form very good synergistic effect with the first ligands.The title complexes possess excellent thermal stability properties,and are hopefully developed into fine PL and EL red materials.
文摘Snowmelt is an important component of any snow-fed river system.The Jhelum River is one such transnational mountain river flowing through India and Pakistan.The basin is minimally glacierized and its discharge is largely governed by seasonal snow cover and snowmelt.Therefore,accurate estimation of seasonal snow cover dynamics and snowmeltinduced runoff is important for sustainable water resource management in the region.The present study looks into spatio-temporal variations of snow cover for past decade and stream flow simulation in the Jhelum River basin.Snow cover extent(SCE) was estimated using MODIS(Moderate Resolution Imaging Spectrometer) sensor imageries.Normalized Difference Snow Index(NDSI) algorithm was used to generate multi-temporal time series snow cover maps.The results indicate large variation in snow cover distribution pattern and decreasing trend in different sub-basins of the Jhelum River.The relationship between SCE-temperature,SCE-discharge and discharge-precipitation was analyzed for different seasons and shows strong correlation.For streamflow simulation of the entire Jhelum basin Snow melt Runoff Model(SRM) used.A good correlation was observed between simulated stream flow and in-situ discharge.The monthly discharge contribution from different sub-basins to the total discharge of the Jhelum River was estimated using a modified version of runoff model based on temperature-index approach developed for small watersheds.Stream power - an indicator of the erosive capability of streams was also calculated for different sub-basins.
文摘Jordan has a good natural potential for solar energy source. To reach at economic practicability of solar energy sources, Jordan needs to accelerate the development of the national photovoltaic projects. The economic and financial analysis of the 75 MW Photovoltaic Project for Jordan is presented in this paper. Comparing analysis considers, seven different scenarios regarding the type of the modules and of the mounting system as well as three different cases to further evaluate the effects of land requirements based on an equivalent installed capacity. Based on the analyzed scenarios, it was found that the project will serve as a "fuel saver", as the energy generated at the Jordan Photovoltaic Project replaces energy generated at the thermal plant with the highest variable costs in the grid. This replacement has it, which avoids the CO2 emissions associated with thermal generation, as the further advantage.
基金supported by the National Basic Research Program of China (2015CB856300)the National Natural Science Foundation of China (21571099, 21731004)the Natural Science Foundation of Jiangsu Province (BK20150054)
文摘Modification of classic fluorophore to possess the emission transitions between aggregation-induced emission (ALE) and intrinsic emission offers reliable approach to the design of ratiometric fluorescent sensors. In this study, a proton acceptor benzimidazole was integrated with BODIPY to form three compounds, BBI-1/2/3, which demonstrated the AIE (-595 nm, Iagg) in neutral aqueous medium and intrinsic BODIPY emission (-510 nm,Iint) in acidic medium. All the three showed the ratiometric pH sensing behavior in a dual excitation/dual emission mode, yet BBI-3 displayed still the dual emission ratiometric pH sensing ability. The pH-dependent emission ratio/int/Iagg of the three were fully reversible, and no interference was observed from normal abundant chemical species in live cells. Their different pKa (BBI-1, pKa 4.4; BBI-2, pKa 2.7; BBI-3, pKa 3.6) suggested that the substituents on benzimidazole moiety were essential to govern their functioning pH range. The ratiometric imaging of BBI-1 in A549 cells provided an effective intracellular pH (pHi) calibration formula corresponding to emission ratio oflJ Iint/Iagg. Ratiometric pH imaging in A549 cells upon small particle exposure confirmed the particle-induced cellular acidification with this formula. Both particle size and the chemical nature of the particle contribute to the observed acidification effect. The synchronization of lysosome disruption to cellular acidification in A549 cells upon crystalline silica exposure was directly observed for the first time with BBI-1, showing the potential application of BBI-1 in the study of silicosis and other related diseases. This study de- monstrated that endowing fluorophore with AIE/intrinsic emission transition could be a promising strategy for ratiometric sensor design.
基金supported by the National Basic Research Program(2014CB932103)the National Natural Science Foundation of China(21301016,21473013)+1 种基金the Beijing Municipal Natural Science Foundation(2152016)the Fundamental Research Funds for the Central Universities
文摘Molecular materials exhibiting room temperature phosphorescence(RTP) have received much attention during last few years. It has been known that different stacking fashions(e.g., formation of polymorph) and aggregation/crystal states could largely influence the RTP efficiency. However, whether the crystal morphology or shape could play a key role in modulation of the RTP has not been detected yet. In this work, we report that the dibenzothiophene(DBT) with the same molecular stacking fashion but different crystal morphologies can present alternated RTP performances. By modulation of the fluorescence and phosphorescence dual emission, a direct warm-white color light-emitting has also been successfully achieved. Moreover, the RTP emission can be further tuned through hybridization with β-cyclodextrin in different ratios, with the longest lifetime of 0.43 s.
基金supported by the National Natural Science Foundation of China(Nos.60877029,10904109,60977035 and 60907021)the Natural Science Foundation of Tianjin(Nos.09JCYBJC01400 and 10SYSYJC28100)+1 种基金the Key Subject for Materials Physics and Chemistry of Tianjinthe Open Foundation of Key Laboratory of Luminescence and Optical Information of Ministry of Education(Nos.2010LOI02 and 2010LOI11)
文摘ZnO nanorods prepared by a solution-phase method are annealed at different temperatures in oxygen ambient.The luminescence properties of the samples are investigated.In the same excitation condition,the photoluminescence(PL) spectra of all samples show an ultraviolet(UV) emission and a broad strong visible emission band.The asymmetric visible emis-sion band of annealed samples has a red-shift as the annealing temperature increasing from 200 ℃ to 600 ℃ and it can be deconvoluted into two subband emissions centered at 535 nm(green emission) and 611 nm(orange-red emission) by Gaussian-fitting analysis.Analyses of PL excitation(PLE) spectra and PL spectra at different excitation wavelengths reveal that the green emission and the orange-red emission have a uniform initial state,which can be attributed to the electron transition from Zn interstitial(Zni) to oxygen vacancy(Vo) and oxygen interstitial(Oi),respectively.
基金funded by the National Basic Research Program of China(2013CB932800)the National Natural Science Foundation of China(21375130,31571010,21204089 and 21475132)
文摘Mercury is one of the major toxic pollutants and has many adverse effects on human health. The main mercury species in the environment or in living organisms are inorganic mercuric ion (Hg2+) and organic methylmercury (CH3Hg+). Detection of the two mercury ions is a particularly active topic in the molecular sensing field during the past decade. However, efficient sensors that can sensitively detect and discriminate the two species are rare. In this work, we adopt the concept of restriction of intramolecular rotations which is the basis of aggregation induced emission, and design a molecular probe with pyridyl group as the chelating unit and 1,8-naphthalimide as the fluorescent unit for the detection of both Hg2+ and CH3Hg+. When the probe is free in solution, it exhibits weak fluorescence because free intramolecular rotations of the 1,8-naphthalimide moieties non-radiatively annihilate its excited state. However, upon coordination with Hg2+ or CH3Hg+, the rotation of 1,8-naphthalimide moieties would be restricted due to the chelation between 1,8-naphthalimide and Hg2+ or CH3Hg+, leading to significantly enhanced fluorescent emission. The response induced by Hg2+ is much stronger than CH3Hg+; but for specific detection of CH3Hg+, we introduced a T-rich DNA fragment which could completely mask Hg2+ in solution. Furthermore, we have employed the sensor for confocal imaging of rig2+ and CH3Hg+in immobilized cells. We expect the probe design tactics can be generally useful for sensing many other analytes.
基金supported by Grants-in-Aid for JSPS KAKENHI (15H03795)MEXT KAKENHI 15K13671+1 种基金the Nagase Science and Technology Foundationthe Ogasawara Foundation for the Promotion of Science and Engineering
文摘Exploration of novel organic luminophores that exhibit thermally activated delayed fluorescence(TADF) in the aggregated state is very crucial for advance of delayed luminescence-based applications such as time-gated bio-sensing and temperature sensing.We report herein that synthesis, photophysical properties, molecular and crystal structures, and theoretical calculations of 2,6-bis(diarylamino)benzophenones. Absorption spectra in solution and calculations using density functional theory(DFT) method revealed that the optical excitation took place through intramolecular charge-transfer from one diarylamino moiety to an aroyl group. While the benzophenones did not luminesce in solution, the solids of the benzophenones emitted green light with moderate-to-good quantum yields. Thus, the benzophenones exhibit aggregation-induced emission. Based on the lifetime measurement, the green emission of the solids was found to include TADF. The emergence of the TADF is supported by the small energy gap between the excited singlet and triplet states, which was estimated by time-dependent DFT calculations. Thin films of poly(methyl methacrylate) doped by the benzophenones also showed green prompt and delayed fluorescence whose lifetimes were in the order of microseconds. Linear correlation between logarithm value of TADF lifetime and temperature was observed with the benzophenone in powder, suggesting that the benzophenones can serve as molecular thermometers workable under aqueous conditions.
基金the National Natural Science Foundation of China (51173018)the National Basic Research Program of China (973 program, 2013CB834704)
文摘Luminescent materials exhibiting emission switching in the solid state have drawn much attention though there is still no clear design strategy for such materials. In this letter, we reported the crystallization induced emission enhancement (CIEE) of di(4-ethoxyphenyl)dibenzofulvene (1), and achieved switching its emission among four different colors through modulation of its molecular packing patterns. We have investigated its potential application as optical recording materials. The twisted conformations of CIEE compounds afford morphology dependent emission and facilitate tuning their emission through modulation of molecular packing patterns. Thus we provide a possible design strategy for solid stimulus responsive luminescent materials.
基金supported by the National Natural Science Foundation of China (51673180, 51373162)
文摘A new dual-state emission(DSE) dye comprised of tetraphenylethene(TPE), triphenylamine(TPA), and indoline groups has been synthesized, which showed efficient fluorescence in both solution and solid. The dye is comprised of three parts and these parts show different fluorescence properties which can be very useful in some applications since the dye can produce information-rich responses. For example, the dye is p H-sensitive in both solution and solid states, and it emits yellow fluorescence in normal p H and red/NIR fluorescence in acidic condition. Cytotoxicity of the dye is low at concentration of 3 μM which was confirmed by a methyl thiazolyl tetrazolium(MTT) experiment, and in vitro experiments revealed that the p H responsive performance can be used in bioimaging. It provides a novel p H-sensitive DSE dye ever reported, which has potential application in many fields.
基金supported by Australian Research Council (DE170100058)Rebecca L. Cooper Medical Research Foundation
文摘Biothiols are important species in physiological processes such as regulating protein structures, redox homeostasis and cell signalling. Alternation in the biothiol levels is associated with various pathological processes, therefore non-invasive fluorescent probes with high specificity to biothiols are highly desirable research utilities. Meanwhile, fluorescent probes with aggregationinduced emission properties(AIEgens) possess unique photophysical properties that allow modulation of the sensing process through controlling the aggregation-disaggregation or the intramolecular rotational motions of the fluorophores. Herein we review the recent progress in the development of biothiol-specific AIEgens. In particular, the molecular design principles to target different types of biothiols and the corresponding sensing mechanisms are discussed, along with the potential of the future design and development of multi-functional bioprobes.
文摘Editor's comments Formaldehyde (HCHO) emitted from chemical manufacturing plants including methanol-gasoline/diesel fuel vehicles and the construction and decoration materials is one of the major air pollutions, which induces photochemical pollution and hazards human health. Great efforts have been made for the reduction or control of the emission of HCHO to satisfy the stringent environmental regulations. Now, a new study supported by the National Natural Science Foundation of China reports mesoporous manganese oxide with novel nanostructures for the decomposition of HCHO. The obtained manganese oxide nanomaterials showed high catalytic activities for oxidative decomposition of HCHO at low temperatures. Complete conversion of HCHO to CO2 and H2O were achieved, and no harmful by- products were detected in effluent gases. The catalytic activities of these nanomaterials are significantly higher than those of previously reported manganese oxide octahedral molecular sieve (OMS-2) nanorods , MnO x powders, and alumnina-supported mangnaese-palladium oxide catalysts. These results provide a new route for the removal of HCHO and other air pollutions.
基金the National Natural Science Foundation of China (51273053, 21104012, 21284034 and 61106017)the Natural Science Foundation of Zhejiang Province (Y4110331)+1 种基金the Program for Changjiang Scholars and Innovative Research Teams in Chinese Universities (IRT 1231)the Project of Zhejiang Key Scientific and Technological Innovation Team (2010R50017)
文摘Tetraphenylethene (TPE) is a popular luminogen characterized by aggregation-induced emission and has been widely used to construct solid-state emissive materials. In this work, two thermally stable polymers (P1 and P2) consisting of TPE conjugated to the 2,7-positions of fluorene and carbazole, respectively, are synthesized and characterized. Both polymers are weakly fluorescent in solutions but show greatly enhanced emission as the aggregate formation, presenting an aggregation-enhanced emission feature. Two kinds of polymer light-emitting diodes are fabricated utilizing P1 and P2 as emitters (EML) (device I: ITO/PEDOT:PSS (45 nm)/PVK:EML (1:1 wt%, 55 nm)/TPBI (38 nm)/Ca:Ag; device II: ITO/PEDOT:PSS (45 nm)/ PVK:OXD-7:EML (3:1:3 wt%, 55 nm)/TPBI (38 nm)/Ca:Ag). The device II of P2 shows the best performances, affording a maximum luminance of 6500 cd/m 2 and a high peak efficiency of 2.11 cd/A.
基金supported by the European Community’s Seventh Framework Programme (FP7/2007-2013) (607585)
文摘The aggregation-induced emission(AIE) phenomenon provides a new direction for the development of organic light-emitting devices. Here, we present a new class of emitters based on 4,4-difluoro-4-bora-3 a,4 a-diaza-s-indacene(BODIPY), functionalized at different positions with tetraphenylethylene(TPE), which is one of the most famous AIE luminogens. Thanks to this modification, we were able to tune the photoluminescence of the BODIPY moiety from the green to the near-infrared(NIR)spectral range and achieve PL efficiencies of ~50% in the solid state. Remarkably, we observed an enhancement of the AIE and up to ~100% photoluminescence efficiencies by blending the TPE-substituted BODIPY fluorophores with a poly[(9,9-di-noctylfluorene-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,7-diyl)](F8 BT) matrix. By incorporating these blends in organic lightemitting diodes(OLEDs), we obtained electroluminescence peaked in the range 650–700 nm with up to 1.8% external quantum efficiency and ~2 m W/cm2 radiance, a remarkable result for red/NIR emitting and solution-processed OLEDs.