The incorporation of fluorine(F_(2)) into hydrogen-air(H_(2)/Air) mixtures presents a novel approach to enhancing the performance of rotating detonation engines(RDEs). This study systematically investigates the effect...The incorporation of fluorine(F_(2)) into hydrogen-air(H_(2)/Air) mixtures presents a novel approach to enhancing the performance of rotating detonation engines(RDEs). This study systematically investigates the effects of F_(2)concentration and inlet mass flow rate on rotating detonation wave(RDW) propagation using two-dimensional numerical simulations, providing the first comprehensive analysis of F_(2)as an oxidizing additive in regulating detonation performance, propagation stability, and heat release dynamics in RDEs. The results indicate that when F_(2)concentration is below 1%, the flow field primarily exhibits a stable single-wave propagation mode. As F_(2)concentration increases, RDW performance initially improves but then deteriorates, reaching its optimal state at 0.8% F_(2). When F_(2)concentration exceeds 1%, the coupled effects of F_(2)concentration and inlet mass flow rate induce a transition from single-wave to multi-wave propagation modes. While a higher inlet mass flow rate promotes increased wave numbers, it also intensifies wave-wave interactions. With further increases in F_(2)concentration, the enhanced heat release leads to intensified local deflagration, frequent hotspot formation, and wave collisions, ultimately degrading RDW performance and destabilizing the multi-wave flow field. Moreover, excessive HF formation is identified as a critical driver of enhanced deflagration, hotspot generation,and the disruption of multi-wave stability. These findings provide a theoretical foundation for integrating F_(2)additives into H_(2)/Air-based RDE systems.展开更多
Indian mustard is recognized as a resilient and economically important oilseed crop.However,its potential remains untapped due to the limited availability of short-duration,high-yielding varieties capable of out-compe...Indian mustard is recognized as a resilient and economically important oilseed crop.However,its potential remains untapped due to the limited availability of short-duration,high-yielding varieties capable of out-competing other rabi crops.Considering this notion,we have evaluated twenty-one F_(2) and six BC1F1 populations derived from seven diversified parents of Brassica juncea following a Randomized Complete Block Design at Sher-e-Bangla Agricultural University.Based on key agronomic traits,the genetic components,heterosis,inbreeding depression,and gene action were studied to select early maturing and high-yielding populations.The percentage of heterosis was manifested in various cross-combinations,including P4×P6(91.45%for yield per plant)and P5×P6(28.52%for thousand seed weight),emerging as promising candidates for increasing productivity while managing negative inbreeding effects.Conversely,significant inbreeding depression was noted in traits like days to siliquae maturity and yield,particularly in crosses,P1×P2(6.29%)and P3×P5(21.74%),underscoring the need for careful selection in breeding programs to mitigate these effects.Variance analysis indicated that both additive and non-additive genetic interactions play a pivotal role in the inheritance patterns of the traits of interest.Among the six backcrosses,one promising line was(P5×P6)×P5,demonstrating early maturity(107.00 DAS)with improved seed yield(12.47 g).This combination exhibited the potential for enhancing the adaptability and productivity by maintaining the maturity index and accelerating yield.Furthermore,significant phenotypic variation across yield-contributing traits was notable,whereas thousand seed weight and yield per plant showed high broad-sense and narrow-sense of heritability.Besides,positive correlations between seed yield and its attributing traits were noted,suggesting potential avenues for selection breeding.Collectively,the ob-tained findings enhance the understanding of genetic mechanisms underlying heterosis and inbreeding depres-sion in B.juncea,providing insights and effective strategies for developing superior cultivars with optimized agronomic traits.展开更多
A novel Eu^(3+)-doped fluorapatite red phosphor Ca_(2)Y_(8)(BO_(4))_(2)(SiO_(4))_(4)F_(2)Eu^(3+)with pure phase was synthesized in this study.Density functional theory(DFT)calculation and diffuse reflection spectrum a...A novel Eu^(3+)-doped fluorapatite red phosphor Ca_(2)Y_(8)(BO_(4))_(2)(SiO_(4))_(4)F_(2)Eu^(3+)with pure phase was synthesized in this study.Density functional theory(DFT)calculation and diffuse reflection spectrum analysis reveal its potential as a matrix for phosphors excited by ultraviolet light.Eu^(3+)has a^(7)F_(0)→^(5)L_(6)transition at 394 nm,and the prepared phosphor exhibits a high emission intensity at 614 nm,which may be attributed to the^(5)D_(0)-^(7)F_(2)energy transition at the lower symmetry site of Eu^(3+).The optimal doping concentration of the phosphor is determined to be 11 mol%,with concentration quenching attributed to the exchange interaction mechanism.The overall color purity of the phosphor is up to 99.88%,with an internal quantum efficiency as high as 91.15%.Notably,Ca_(2)Y_(8)(BO_(4))_(2)(SiO_(4))_(4)F_(2):11 mol%Eu^(3+)(CYBSF:11 mol%Eu^(3+))phosphors exhibit good thermal stability,with a thermal quenching temperature(T1/2)of 552 K and the intensity of emission at 423 K still at 88.89%of that at 298 K.The activation energy of the phosphor is up to 0.30287 eV.Its comprehensive luminescence performance surpasses that of commercial red phosphor,making it suitable for near ultraviolet excited warm white light emitting diode(NUV-WLED)with a high color rendering index(Ra=82)and a correlated color temperature(CCT)of 4339 K.Moreover,the phosphor achieves latent fingerprint visualization and anti-counterfeiting ink on different material surfaces:glass,aluminum foil,plastic and paper.Overall,the fluorapatite CYBSF:11 mol%Eu^(3+)phosphor holds great potential for multimodal applications due to its high quantum efficiency and good thermal stability.展开更多
文摘[目的]溴虫氟苯双酰胺是新型间二酰胺类杀虫剂,本文通过棉铃虫(Helicoverpa armigera)对溴虫氟苯双酰胺的室内抗性发展情况的探究和田间抗性等位基因频率的调查,全面评估棉铃虫对溴虫氟苯双酰胺的抗性风险,为该药剂的合理使用提供科学依据。[方法]用溴虫氟苯双酰胺对棉铃虫室内品系SCD进行连续多代筛选,根据阈性状分析法计算其抗性现实遗传力(realized heritability of resistance,h^(2));用F_(2)筛选法检测棉铃虫田间种群对溴虫氟苯双酰胺的抗性等位基因频率。[结果]70%左右死亡率的选择压力下连续筛选10代和20代,棉铃虫对溴虫氟苯双酰胺的抗性现实遗传力(h^(2))分别为0.1268和0.0592;在筛选过程中棉铃虫对溴虫氟苯双酰胺的抗性倍数为1.9~4.5,到第20代时抗性倍数为2.8。2022年华北棉区325个棉铃虫田间单雌系F_(2)代幼虫共31200头在溴虫氟苯双酰胺诊断浓度下全部死亡,说明检测的田间单雌系均未携带抗性等位基因,华北棉区棉铃虫田间种群对溴虫氟苯双酰胺的抗性等位基因频率为0.0008(95%CI:0.0000~0.0050)。[结论]棉铃虫室内品系连续多代筛选对溴虫氟苯双酰胺的抗性发展缓慢,F_(2)筛选检测表明田间种群的起始抗性等位基因频率低,因此棉铃虫对溴虫氟苯双酰胺的抗性风险低,可有效用于棉铃虫的防治。
文摘The incorporation of fluorine(F_(2)) into hydrogen-air(H_(2)/Air) mixtures presents a novel approach to enhancing the performance of rotating detonation engines(RDEs). This study systematically investigates the effects of F_(2)concentration and inlet mass flow rate on rotating detonation wave(RDW) propagation using two-dimensional numerical simulations, providing the first comprehensive analysis of F_(2)as an oxidizing additive in regulating detonation performance, propagation stability, and heat release dynamics in RDEs. The results indicate that when F_(2)concentration is below 1%, the flow field primarily exhibits a stable single-wave propagation mode. As F_(2)concentration increases, RDW performance initially improves but then deteriorates, reaching its optimal state at 0.8% F_(2). When F_(2)concentration exceeds 1%, the coupled effects of F_(2)concentration and inlet mass flow rate induce a transition from single-wave to multi-wave propagation modes. While a higher inlet mass flow rate promotes increased wave numbers, it also intensifies wave-wave interactions. With further increases in F_(2)concentration, the enhanced heat release leads to intensified local deflagration, frequent hotspot formation, and wave collisions, ultimately degrading RDW performance and destabilizing the multi-wave flow field. Moreover, excessive HF formation is identified as a critical driver of enhanced deflagration, hotspot generation,and the disruption of multi-wave stability. These findings provide a theoretical foundation for integrating F_(2)additives into H_(2)/Air-based RDE systems.
基金funded by Bangladesh Academy of Sciences(BAS),and Fund ID:BAS-USDA SAU CR02.
文摘Indian mustard is recognized as a resilient and economically important oilseed crop.However,its potential remains untapped due to the limited availability of short-duration,high-yielding varieties capable of out-competing other rabi crops.Considering this notion,we have evaluated twenty-one F_(2) and six BC1F1 populations derived from seven diversified parents of Brassica juncea following a Randomized Complete Block Design at Sher-e-Bangla Agricultural University.Based on key agronomic traits,the genetic components,heterosis,inbreeding depression,and gene action were studied to select early maturing and high-yielding populations.The percentage of heterosis was manifested in various cross-combinations,including P4×P6(91.45%for yield per plant)and P5×P6(28.52%for thousand seed weight),emerging as promising candidates for increasing productivity while managing negative inbreeding effects.Conversely,significant inbreeding depression was noted in traits like days to siliquae maturity and yield,particularly in crosses,P1×P2(6.29%)and P3×P5(21.74%),underscoring the need for careful selection in breeding programs to mitigate these effects.Variance analysis indicated that both additive and non-additive genetic interactions play a pivotal role in the inheritance patterns of the traits of interest.Among the six backcrosses,one promising line was(P5×P6)×P5,demonstrating early maturity(107.00 DAS)with improved seed yield(12.47 g).This combination exhibited the potential for enhancing the adaptability and productivity by maintaining the maturity index and accelerating yield.Furthermore,significant phenotypic variation across yield-contributing traits was notable,whereas thousand seed weight and yield per plant showed high broad-sense and narrow-sense of heritability.Besides,positive correlations between seed yield and its attributing traits were noted,suggesting potential avenues for selection breeding.Collectively,the ob-tained findings enhance the understanding of genetic mechanisms underlying heterosis and inbreeding depres-sion in B.juncea,providing insights and effective strategies for developing superior cultivars with optimized agronomic traits.
基金supported by the National Natural Science Foundation of China(52372013)Natural Science Foundation of Shanghai(22ZR1460600)。
文摘A novel Eu^(3+)-doped fluorapatite red phosphor Ca_(2)Y_(8)(BO_(4))_(2)(SiO_(4))_(4)F_(2)Eu^(3+)with pure phase was synthesized in this study.Density functional theory(DFT)calculation and diffuse reflection spectrum analysis reveal its potential as a matrix for phosphors excited by ultraviolet light.Eu^(3+)has a^(7)F_(0)→^(5)L_(6)transition at 394 nm,and the prepared phosphor exhibits a high emission intensity at 614 nm,which may be attributed to the^(5)D_(0)-^(7)F_(2)energy transition at the lower symmetry site of Eu^(3+).The optimal doping concentration of the phosphor is determined to be 11 mol%,with concentration quenching attributed to the exchange interaction mechanism.The overall color purity of the phosphor is up to 99.88%,with an internal quantum efficiency as high as 91.15%.Notably,Ca_(2)Y_(8)(BO_(4))_(2)(SiO_(4))_(4)F_(2):11 mol%Eu^(3+)(CYBSF:11 mol%Eu^(3+))phosphors exhibit good thermal stability,with a thermal quenching temperature(T1/2)of 552 K and the intensity of emission at 423 K still at 88.89%of that at 298 K.The activation energy of the phosphor is up to 0.30287 eV.Its comprehensive luminescence performance surpasses that of commercial red phosphor,making it suitable for near ultraviolet excited warm white light emitting diode(NUV-WLED)with a high color rendering index(Ra=82)and a correlated color temperature(CCT)of 4339 K.Moreover,the phosphor achieves latent fingerprint visualization and anti-counterfeiting ink on different material surfaces:glass,aluminum foil,plastic and paper.Overall,the fluorapatite CYBSF:11 mol%Eu^(3+)phosphor holds great potential for multimodal applications due to its high quantum efficiency and good thermal stability.
