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Most geophysical and geochemical data are commonly acknowledged to exhibit fractal and multifractal properties, but the fractal characteristics of polarizability have received limited attention from the literature. The present study demonstrates that the polarizability data of the graphite deposits have fractal characteristics and introduces the fractal method for its quantitative analysis to indicate and predict the properties of graphite deposits. The results show that the concentration-area (C-A) method is superior to classical interpolation in anomaly extraction but inferior to the spectrum-area (S-A) method in the coverage region. Because the type of graphite ore is sedimentary-metamorphic in this area, the graphite ore-bodies can be regarded as a special stratum, which is different from most metal deposits, and the anomaly of graphite ore are shown in the background mode of the S-A method. The high values of the background mode effectively indicate the potential areas where the graphite-bearing strata occur, while observing a decrease in the power-law exponent (β) of the background mode as the width of ore-bodies increases. The validity of this conclusion was confirmed based on the vertical profiles of the predicted area, and the uncharted ore vein was thereby identified. Furthermore, it was found that the anomaly mode can serve as a grade indicator of graphite ore rather than delineating the fault. By integrating the background and anomaly modes of the S-A method, we can quantitatively predict and effectively identify high-grade targets from sedimentary deposits containing minerals in future exploration. [ABSTRACT FROM AUTHOR]

Wavelet transformation has been widely used in geophysical and geochemical exploration, and the fractal feature of wavelet coefficients has recently stood out from many wavelet threshold methods. We introduced the wavelet–fractal method to analyze the polarizability and resistivity of graphite deposits. Due to the unique nature of graphite-bearing gneiss, characterized by high polarizability and low resistivity, we concluded that the polarizability background mode is better suited to depict the morphology of the graphite-bearing formation, with the resistivity background mode serving as complementary information for verification. Symlets5 is regarded as the optimal mother wavelet to indicate the characteristics of graphite ore by means of comparison and analysis. The polarizability anomalies showed two different linear forms: the direction of the measuring line and the strike of the ore bodies. According to the data of drill holes on the profile, we inferred that the high values of the anomaly mode can be used to delineate the target area where the graphite is enriched. Combining the application of both modes, we used the wavelet–fractal method for the quantitative prediction and effective selection of a potential area with a high grade. The approach used in this current study can be extended to the prospecting of other graphite deposits or sedimentary–metamorphic deposits containing conductive minerals, where geochemical and geophysical data are available. [ABSTRACT FROM AUTHOR]

Nano-bubble irrigation, as a new irrigation technology, can deliver fertilizer-mixed oxygen-enriched water to the root zone of crops, representing a new means for increasing crop yield and carbon sequestration and emission reduction. To systematically analyze the effects of nano-bubble irrigation on crop yield, soil aeration, and soil greenhouse gas (GHG) emissions, as well as evaluating its contribution to the net greenhouse warming potential (NGWP) in greenhouse agriculture, this study was conducted in greenhouse facilities in Zhengzhou, China and focused on tomato plants. A 2-factor, 2-level, completely randomized trial of nitrogen application (low N1: 120 kg/hm2 and normal N2: 180 kg/hm2), conventional irrigation, and nano-bubble irrigation (C: 5 ppm and A: 15 ppm) was conducted. Compared with conventional irrigation, crop yield increased by 18.94% and 16.36% (p < 0.05), CO2 emission by 10.72% and 5.71% (p < 0.05), N2O emission by 29.76% and 35.74% (p < 0.05), and CH4 uptake by 300.67% and 327.67% (p < 0.05) under nano-bubble irrigation. The nano-bubble irrigation increased the crop yield, thus significantly improving the NGWP sink for greenhouse gases. The low-nitrogen and regular-nitrogen treatments increased NGWP by 22.69% and 14.52%, respectively (p < 0.05). This suggests that nano-bubble irrigation can significantly improve soil aeration, increase tomato yield and biomass, and significantly improve crop carbon sequestration. In the future, nano-bubble irrigation can be used along with soil amendments to achieve a more efficient increase in yield and enhance the ability of farmland to sequester carbon and reduce emissions. [ABSTRACT FROM AUTHOR]

The arctic strain of Chlorella sp. (Chlorella-Arc) exists in the coldest and driest arctic ecosystems, and it is a new resource of active polysaccharides. The extraction of crude polysaccharide from Chlorella-Arc was optimized using the response surface methodology. A crude polysaccharide yield of approximately 9.62 ± 0.11% dry weight was obtained under these optimized conditions. Three fractions (P-I, P-II, and P-III) were present after purification by 2-diethylaminoethanol Sepharose Fast Flow and Sephadex G-100 chromatography. The P-IIa fraction demonstrated significant antioxidant activities. Moreover, P-IIa was an α- and β-type heteropolysaccharide with a pyran group and contained variable amounts of rhamnose, arabinose, glucose, and galactose based on fourier-transform infrared spectroscopy, high-performance liquid chromatography, and ¹H and 13C nuclear magnetic resonance imaging. Production of high amounts of polysaccharide may allow further exploration of the microalgae Chlorella-Arc as a natural antioxidant. [ABSTRACT FROM AUTHOR]