Fe₃O₄–Graphite Composites as a Microwave Absorber with Bimodal Microwave Absorption

Microwave absorption in the low-frequency region is a major challenge in the development of carbon-based absorbers. Fe3O4–graphite composites with both low-frequency region and high-frequency region absorption were prepared through a facile solvothermal method. The electromagnetic properties and impedance matching characteristics of the samples were regulated by changing the dosage of graphite. Interestingly, an excellent bimodal microwave absorption (MA) performance was obtained when the molar ratio of iron and graphite was 3:10 (Fe3O4–2PG). With the optimal matching thickness of 4 mm, the Fe3O4–2PG sample shows good performances with respect to the effective absorption bandwidth of 3.3 GHz; the minimum reflection loss (RLmin) in C-band (4–8 GHz) is −40.6 dB, and its RLmin in Ku-band (12–18 GHz) is −29.82 dB. The good bimodal MA performance of Fe3O4–2PG could be attributed to the synergistic effects and interfacial polarization between Fe3O4 nanoparticles and graphite. Furthermore, Fe3O4–2PG and Fe3O4–1PG have electromagnetic absorption peaks in both the C-band and Ku-band, which broaden the absorption band of electromagnetic waves, which is beneficial to solve the problem of 5 G electromagnetic radiation. Therefore, the research results have special significance for the radiation interference of 5 G technology and the shielding absorption of C-band radar waves

Effects of lanthanum and acid rain stress on the bio-sequestration of lanthanum in phytoliths in germinated rice seeds

<div><p>REEs in the environment can be absorbed by plants and sequestered by plant phytoliths. Acid rain can directly or indirectly affect plant physiological functions. Currently, the effects of REEs and acid rain on phytolith-REEs complex in plants are not yet fully understood. In this study, a high-silicon accumulation crop, rice (<i>Oryza sativa</i> L.), was selected as a representative of plants, and orthogonal experiments were conducted under various levels of lanthanum [La(III)] and pH. The results showed that various La(III) concentrations could significantly improve the efficiency and sequestration of phytolith La(III) in germinated rice seeds. A pH of 4.5 promoted phytolith La(III) sequestration, while a pH of 3.5 inhibited sequestration. Compared with the single treatment with La(III), the combination of La(III) and acid rain inhibited the efficiency and sequestration of phytolith La(III). Correlation analysis showed that the efficiency of phytolith La(III) sequestration had no correlation with the production of phytolith but was closely correlated with the sequestration of phytolith La(III) and the physiological changes of germinated rice seeds. Phytolith morphology was an important factor affecting phytolith La(III) sequestration in germinated rice seeds, and the effect of tubes on sequestration was more significant than that of dumbbells. This study demonstrated that the formation of the phytolith and La(III) complex could be affected by exogenous La(III) and acid rain in germinated rice seeds.</p></div

Effects of La (at a LaCl₃ concentration of 0, 20, 100 or 300 mg/L) and acid rain (at pH value of 3.5, 4.5 or 5.5) on phytolith content (a), PhytLa content (b), the PhytLa content in seeds (c) and the PhytLa content/phytolith content ratio (d).

<p>Error bars are standard deviations (n = 4); different letters indicate significant differences between different treatments at P = 0.05 based on the least significant difference (LSD) test.</p

Correlation analysis of the vigour index of germinated rice seeds.

<p>Correlation analysis of the vigour index of germinated rice seeds.</p

Additional file 1 of Association between dietary knowledge and overweight/obesity in Chinese children and adolescents aged 8–18 years: a cross-sectional study

Additional file 1: Supplementary Table 1. International cut off points for body mass index for overweight and obesity by sex between 2 and 18 years, defined to pass through body mass index of 25 and 30 kg/m2 at age 18, obtained by averaging data from Brazil, Great Britain, Hong Kong, Netherlands, Singapore, and United States [1]. Supplementary Table 2. Sensitivity analysis of interpolation data. Supplementary Table 3. The association between diet knowledge and overweight and obesity in children and adolescents

Correlations among PhytLa content, phytolith content and the PhytLa content in seeds.

<p>a PhytLa content vs. phytolith content; b phytolith content vs. the PhytLa content in seeds; c PhytLa content vs. the PhytLa content in seeds. n = 48.</p

Formulas for the calculation of indicators of seed germination.

<p>Formulas for the calculation of indicators of seed germination.</p

Effects of different pH levels on phytolith morphology (here, the LaCl₃ concentration was 0 mg/L).

<p>The pH values from top to bottom are 5.5, 4.5 and 3.5, and the phytolith morphotypes from left to right are dumbbells, tubes, crenates, elongate smooths and elongate echinates.</p

Using Ionic Liquid Mixtures To Improve the SO₂ Absorption Performance in Flue Gas

The functional ionic liquids (ILs) [NH₂emim]­[OAc] and [NH₂emim]­[BF₄] were synthesized for SO₂ capture. Although functional ILs have potential advantages in SO₂ absorption, the high viscosity of a single IL markedly affects the SO₂ absorption separation process. To improve the SO₂ absorption performance, [NH₂emim]­[OAc] and [NH₂emim]­[BF₄] were mixed with low-viscosity imidazolium-based ILs [bmim]­[OH]/[bmim]­[BF₄]. When the mole ratio of [NH₂emim]­[OAc]/[bmim]­[OH] is about 1:1, the binary mixture has the best SO₂ absorption capacity. The SO₂ absorption performance was investigated in the simulated flue gas, where SO₂ partial pressure was about 0.2 kPa. Under the low SO₂ partial pressure, the absorption capacity of the [NH₂emim]­[OAc] + [bmim]­[OH] mixture was more than 0.7 mol of SO₂/mol of IL, which was superior to that of a single IL. The regeneration test of [NH₂emim]­[OAc] + [bmim]­[OH] showed that the binary mixture had high reversibility and the SO₂ absorption capacity almost kept constant after 12 recycles. The viscosity and density of the IL mixture changed slightly, which only have a 2–3% increase in each cycle

Effects of La (at LaCl₃ concentrations of 0, 20, 100 and 300 mg/L) and acid rain (at a pH of 3.5, 4.5 or 5.5) on the seed vigor index of rice germinated seeds [GI (a), RL (b), FW (c) and DW (d)].

<p>Error bars are standard deviations (n = 4). Different letters indicate significant differences between different treatments at P = 0.05 based on the least significant difference (LSD) test.</p