The spectral optimization of phosphor-coated white LED (pc-WLED) with green and orange phosphors excited by blue chip for road lighting was investigated based on the mesopic limited luminous efficacy (LLE) and IES (the Illuminating Engineering Society of North America) color fidelity index (R). The average LLE of four road lighting standards of the USA and the UK decreases as R increases, but the optimal scotopic/photopic ratio increases slightly with R increases for a given correlated color temperature (CCT). The average LLE could reach the highest of 339  lm/W for R=70, 326  lm/W for R=80, and 309  lm/W for R=90 at CCT=5000  K. Six real pc-WLEDs with different R at CCT≈5000  K and with R≈70 at different CCT were demonstrated. Compared with current pc-WLEDs with yttrium aluminum garnet doped with Ce (YAG:Ce) phosphors, the average LLE of six demonstrated pc-WLEDs will be over 5.0% and above. So, it is suggested that the road lighting should choose pc-WLEDs with high efficiency green phosphors (520-530 nm) instead of YAG:Ce phosphors.

The photometric model for the mesopic luminous efficacy (LE) of hybrid white LEDs, including the radiant efficiency of both blue and red LEDs as well as the overall quantum efficiency of the phosphor layer or the quantum dot (QD) film, was developed. The optimal spectral parameters of integrated with quantum dots (QD-WLED), phosphor-converted white LED (pc-WLED) with red LEDs instead of red phosphor (pc/R WLED) for both color fidelity index (R) and color rendering index (R) above 70, 80, and 90 at correlated color temperatures of 2700-6500 K were obtained by maximizing the average LE of four road lighting standards. By comparing among pc-WLED, QD-WLED, and pc/R WLED, it was suggested that the pc/R WLEDs make strong candidates for mesopic road lighting. The requirements of the overall efficiency of QD film were presented if the QD-WLEDs were competitive to the pc-WLEDs. Finally, the three real pc/R WLEDs with both R and R about 80 at CCTs of 2982 K, 4560 K, and 5683 K were demonstrated.

Volcanic ash improves the amount of nutritive elements in the lake and ocean, but it is not fully understood how volcanic ash influences the total organic matter content (TOC) and bio-precursor, and the scope. A volcanic layer, measuring 5 cm in thickness, was examined using electron microscopy scanning, TOC/TS, rock pyrolytic, and inorganic geochemical analyses. The study shows that the TOC content in the overlying shales increases by 18 wt.% on average, and the vertical scope of influence on shales is twice as thick as the volcanic layer. Organic matter enrichment is attributed to the fact that the volcanic layer provides nutritive elements and meanwhile changes the oxidation-reduction condition. Large variations of hydrogen index (HI) and oxygen index (OI) in the lower and upper parts of the volcanic layer is related to terrestrial organic matter vanishing, due to volcanic eruption and subsequently more terrigenous organic matter migrating into the ocean. Little change of the bio-precursor in the overlying and underlying shales may be related to the fast restoration within the ocean and land ecosystems after a volcanic eruption. The decrease in terrigenous sediments indicated by Rb/Sr, Zr/Y, and ∑REE after a volcanic eruption indirectly reflects fast restoration of terrestrial vegetation boom. This study could decipher the influence of volcanic ash on the qualities of the source rock, which can provide a better understanding on discovering more economically petroleum reservoirs in igneous rocks.

No abstract

Hydrocarbon-generating material determines the elemental composition and hydrocarbon-generating potential of kerogens in a source rock, and it is the key material basis to control the hydrocarbon-generating capacity of the source rock. Previous studies have shown that many intervals of high-quality source rocks generally contain a varying number of volcanic ash layers. The impact of these volcanic ash layers on the development of high-quality source rocks has attracted extensive attention. However, these studies mainly focused on the development of hydrocarbon-forming organisms and the preservation of organic matters but rarely dealt with the differential development of hydrocarbon-forming organisms between multiple volcanic ash layers. The Permian Dalong Formation in the northwestern Sichuan Basin, China, is a set of high-quality source rocks with multiple volcanic sedimentary layers. To understand the differential development of hydrocarbon-forming organisms between volcanic ash layers, with the Dalong Formation in the Longfeng quarry section, Guangyuan, the Sichuan Basin as an example, this study analyzes the types of hydrocarbon-generating materials of high-quality source rocks of the Dalong Formation and the reasons why volcanic activities affected the growth of hydrocarbon-forming organisms and explores the impact of volcanic activities on the development of different types of hydrocarbon-forming organisms. The results show that the TOC of the Longfeng quarry section is 0.05%–15.46%, with an average of 4.76%, and the average TOC of the Dalong Formation is as high as 5.16%, which belongs to high-quality source rocks. The hydrocarbon-forming organism association in the Dalong Formation source rocks is mainly composed of floating algae and benthic algae and vertically divided into three parts: a few radiolarians and trace fossils occasionally in the lower part; a large number of radiolarians, calcium spheres, and algal debris in the middle part; and mainly foraminifera and gastropods in the upper part. There are 36 volcanic ash layers in the Dalong Formation of the study area. In the process of volcanic activity, the “fertilization” effect of volcanic ash made the nutrient elements in the volcanic ash enter water, increasing the number of hydrocarbon-forming organisms, causing the differential development of various hydrocarbon-forming organisms, and promoting the formation of reducing water to support the preservation of organic matters. The development of hydrocarbon-forming organisms is controlled by the changes of element types and abundances caused by magmatic properties. The time interval of volcanic activities also has an important impact on the development of hydrocarbon-forming organisms.