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• A systematic study of spatiotemporal evolution of extreme ultraviolet spectra in laser-produced germanium (Ge) plasmas is performed with aid of a spatio-temporally resolved emission spectroscopy and multiconfiguration Hartree-Fock calculations. • In combination with a steady-state collisional-radiative model, an analysis of the spectral diagnostics and dynamic evolution of the Ge plasma was completed that revealed the distributions and contributions of the different transition arrays from the Ge4+-Ge13+ ions. • The radiation transition distribution of the Ge ions and the dynamic analysis of the plasma show that the plasma exhibits rapid overall temporal and spatial evolution, with significant gradients in both the electron temperature and the electron density. This paper presents comprehensive spectral measurements and a theoretical analysis of laser-produced germanium (Ge) plasma within the 7.5–17 nm wavelength range, with the measurements being performed using spatiotemporally-resolved emission spectroscopy. We obtained and analyzed the extreme ultraviolet (EUV) spectra and their variations meticulously at various positions adjacent to the target surface. The 3p and 3d excitations of Ge ions spanning from Ge4+ to Ge13+ were calculated using the Cowan configuration interaction codes, with particular emphasis being placed on analysis of the spectral line distributions in the 3d-np, 3d-nf, and 3p-3d, 4s, 4d transition arrays. This analysis indicated the contributions made by these transition arrays to the broadband spectral features that were observed experimentally. By using a steady-state collisional radiation model along with a normalized Boltzmann distribution assumption, we clarified the predominant contributions of the 3d-4p and 3p-3d transitions from the Ge7+ to Ge9+ ions in close proximity to the target surface, along with those from the Ge5+ and Ge6+ ions at greater distances. Furthermore, by combining the results above with a plasma dynamics evolution analysis, we gained insights into how the plasma's transient and nonuniform properties influence the analysis of complex EUV band spectral profiles and examine their implications for spectral diagnostics. These results will be useful for plasma spectral diagnosis and for application to development of pulsed short-wavelength light sources. [ABSTRACT FROM AUTHOR]

The thermal dispersion power depends on thermal conductivity and thickness of the thermal dispersion material that is a critical component of modern electronic devices due to the demands of high operating power in a miniaturized space. Films made of assembled graphene flakes have been becoming an emerging thermal dispersion material owing to their high thermal conductivity and tunable thickness up to millimeters, which outperform that of artificial graphite films made from polyimide. But the thermal conductivity typically decreases with the increase of film thickness. In our work, by pre-reducing the graphene oxide with Vitamin C and sequentially annealing the stacking films at 2950 °C, a 80 μm-thick graphene film (GF) with an in-plane thermal conductivity of above 1600 W/(m·K) is achieved. Detailed characterizations indicate that, the addition of Vitamin C is beneficial to the assembly ordering of graphene oxide platelets and the defect healing during the thermal annealing, which both contribute to the excellent thermal conductivity of the films. Our work provides an industrially scalable strategy towards high performance heat dissipation films for future electronic devices. [Display omitted] [ABSTRACT FROM AUTHOR]

In terrestrial ecosystems, phosphorus (P) is the limiting nutrient of primary production. The soil organic horizon is a vital source of bioavailable P in subalpine coniferous forests. However, the response of organic horizon P to temperature increase in subalpine coniferous forests is not well characterized. By studying different decomposed degree of organic horizon across an altitudinal gradient, we aimed to simulate responses of the organic horizon P conversion to MAT increase in subalpine ecosystems. In this study, relative enrichment and relative depletion of P fractions were defined as the conversions between different P fractions. We initially observed only unidirectional conversion from labile inorganic P (LIP) to highly resistant organic P (HOP) at a mean annual temperature (MAT) of 1 °C. However, with increasing MAT, there was a relative depletion of moderately resistant inorganic P (MIP) (MAT = 2.4 °C), followed by a successive depletion of moderately resistant organic P (MOP) (MAT = 4.1 °C). Concurrently, we observed relative enrichment of labile organic P (LOP) (MAT = 2.4 °C). Combined with indoor incubation experiments, we further found that the concentration of available P peaked (81.79 mg kg−1) at the initial stage of MIP relative depletion (MAT = 2.4 °C), while the net P mineralization rate (2.19 mg kg−1 d−1) reached a maximum following the initial relative depletion of MOP (MAT = 4.1 °C). Under elevated temperature, the pH of the organic horizon plays a crucial role in determining P fractions variation. These findings suggest that temperature increase can exacerbate the conversion of P fractions and the release of bioavailable P from organic horizon by successively triggering the relative depletion of MIP, the relative enrichment of LOP and relative depletion of MOP at specific MAT thresholds, which has important implications for the enhancement of primary production and carbon sequestration in subtropical coniferous forests under future climate warming. • There was only a unidirectional conversion from LIP to HOP at a MAT of 1.0 °C. • As The MAT increased, MIP began to be released at a MAT of 2.4 °C, followed by degradation of MOP at a MAT of 4.1 °C. • As The MAT increased, LIP began to show significant enrichment at a MAT of 2.4 °C. • The concentration of AP exhibited a significant peak at the initial stage of MIP release at a MAT of 2.4 °C. • The net release rate of AP reached relative stability following the initial degradation of MOP at a MAT of 4.1 °C. [ABSTRACT FROM AUTHOR]