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In this study, variations in the free radical concentration, degree of swelling (Q), and extraction yield of Buertai coal (C%, 80.4%) in 11 solvents with different characteristics were determined to investigate the interaction between the coal and solvent, as well as the bond cleavage during solvent extraction. Derivative thermogravimetry (DTG) results for the residues and raw coal were compared to confirm whether the covalent bond breaks during solvent extraction. The free radical concentration decreases in certain solvents but increases in a few others. The relative free radical concentration, Q, and extraction yield are positively correlated. The charge-transfer capability of the solvent, and in particular its electron-donating capability, plays an essential role in influencing the interaction between the coal and solvent. The increase in the free radical concentration during solvent extraction can be attributed to (1) the formation or decomposition of charge-transfer complexes, (2) dissociation of charge-transfer complexes into radical ions, and (3) breakage of weak covalent bonds. DTG results show the occurrence of weak covalent bonds breakage at temperatures of 133.9–320.1 °C during solvent extraction due to the reduction of the bond energy caused by the formation of radical ions.

Compliant substrates are one of the many promising lattice engineering approaches for hetero-epitaxy. There are many approaches to realize such compliant substrates. Silicon-on-insulator (SOI) wafer is a good option as it is readily available from industry. Previous studies on SOI using silicon thicker than 10 nm on insulator reported limited or no compliance. However, the effect of ultrathin silicon thickness ( 4 nm, the GaAs film is multi-crystalline. These films have been characterized by X-ray diffraction measurement, atomic force microscopy and transmission electron microscopy. These findings show the potential for SOI wafers as compliant substrates at ultrathin Si thicknesses.

Single crystalline Ge-rich SixGe1-x epitaxially grown on a Si substrate is attracting great attention for its potential in optical and electronic device applications. One method of achieving SixGe1-x epitaxy is by aluminium-assisted crystallization although the challenge of controlling the Si content in the SixGe1-x is limited by the furnace annealing process. Herein, we report the use of a diode laser to induce aluminium-assisted crystallization of SixGe1-x on Si with minimal Si content in the SixGe1-x layer. By replacing furnace heat treatment with laser treatment, the reaction time is shortened from minutes to milliseconds which can limit the amount of Si incorporation into the SixGe1-x films. X-ray diffraction, Raman spectroscopy, transmission electron microscopy and X-ray spectroscopy analyses are conducted on the fabricated films revealing the achievement of Ge-rich SixGe1-x on Si through laser-induced aluminium-assisted crystallization. The higher laser dose may slightly increase the Si content and improve the crystallinity of the SixGe1-x films.

In this work, magnetron sputtering was used to epitaxially grow Ge films on sapphire at low temperatures (400 °C–500 °C) and diode laser annealing was employed to improve the crystallinity of the Ge films. The deposition temperature might slightly influence the crystallinity of the Ge film through affecting the diffusion rate of Ge. After laser scans of milliseconds exposure time, significant defect density reduction and removal of polycrystalline portion are achieved. Magnetron sputtering combined with diode laser annealing offers a low-cost and fast method in fabricating high quality single crystalline Ge on sapphire which is potentially capable of large-scale production.

The effects of Al layer thickness on one-step aluminium-assisted crystallization of Ge on Si have been investigated and a better understanding of the Ge growth mechanism has been obtained. The thickness of the final Ge layer is larger than the initial Al layer. The Ge growth can be divided into two stages: (i) a predominantly-vertical growth until the Ge reaches the Al surface followed by (ii) a predominantly-lateral growth with a slow vertical growth rate in order to form a continuous film. The results suggest that surplus Ge is required to obtain continuous Ge layers in one-step aluminium-assisted crystallization.

In situ X-ray diffraction study is applied to investigate the role of annealing time in the epitaxial growth of Si x Ge 1−x on Si by aluminium-assisted crystallization at relatively low temperatures (350–450 °C). The evolution of the Si x Ge 1−x film with annealing time can be divided into two stages: (i) Si x Ge 1−x epitaxial growth on Si through Ge/Al layer exchange and (ii) Si x Ge 1-x diffusion into Si substrate. The speed of layer exchange increases with elevating temperature. After the completion of layer exchange, the Si x Ge 1−x starts diffusing into the Si substrate with prolonged annealing time. The Si content of the epitaxial Si x Ge 1−x film keeps increasing with time throughout the annealing. This increase is rapid during Ge/Al layer exchange but is gradual during Si x Ge 1−x diffusion into Si substrate.

In this work, epitaxial Ge films grown on Si by magnetron sputtering were annealed by diode laser as a replacement for conventional thermal annealing to reduce the threading dislocation density (TDD). After laser scans of millisecond exposure time, improvement of crystallinity and increase in tensile strain are observed in the Ge films. TDD of the Ge film is reduced by two orders of magnitude from 1010 cm− 2 to 108 cm− 2 after only three laser scans. Diode laser annealing is a fast and low-cost method to effectively reduce TDD in epitaxial Ge films on Si.

Epitaxial Ge on Si could be used as a virtual Ge substrate for III-V solar cells which has superior mechanical properties and is less expensive than Ge wafers. Aluminiumassisted crystallization via magnetron sputtering offers a low-cost method allows the epitaxy of Ge on Si at low temperatures. The novelty of our one-step aluminium-assisted crystallization of Ge epitaxy on Si lies in the elimination of the post-deposition annealing step. Our process simply requires sequential depositions of Al and Ge films via magnetron sputtering in the same chamber without breaking the vacuum. By applying an insitu low-temperature ($100 ^{\circ}C$) heat treatment in between Al and Ge depositions, Ge epitaxy on Si is achieved.

Uneven distribution and local concentration of protein complexes on distinct membrane cortices is a fundamental property in numerous biological processes, including Drosophila neuroblast (NB) asymmetric cell divisions and cell polarity in general. In NBs, the cell fate determinant Numb forms a basal crescent together with Pon and is segregated into the basal daughter cell to initiate its differentiation. Here we discover that Numb PTB domain, using two distinct binding surfaces, recognizes repeating motifs within Pon in a previously unrecognized mode. The multivalent Numb-Pon interaction leads to high binding specificity and liquid-liquid phase separation of the complex. Perturbations of the Numb/Pon complex phase transition impair the basal localization of Numb and its subsequent suppression of Notch signaling during NB asymmetric divisions. Such phase-transition-mediated protein condensations on distinct membrane cortices may be a general mechanism for various cell polarity regulatory complexes., Polarized localization of Numb and Pon in Drosophila neuroblasts (NBs) enables their unequal segregation during asymmetric cell divisions. Here, the authors demonstrate liquid-liquid phase separation of Pon and Numb in NBs mediated by multivalent intermolecular interactions is required for their basal condensation.

Traffic of cargo across membranes helps establish, maintain, and reorganize distinct cellular compartments and is fundamental to many metabolic processes. The cargo-selective endocytic adaptor Numb participates in clathrin-dependent endocytosis by attaching cargoes to the clathrin adaptor α-adaptin. The phosphorylation of Numb at Ser(265) and Ser(284) recruits the regulatory protein 14-3-3, accompanied by the dissociation of Numb from α-adaptin and Numb's translocation from the cortical membrane to the cytosol. However, the molecular mechanisms underlying the Numb–α-adaptin interaction and its regulation by Numb phosphorylation and 14-3-3 recruitment remain poorly understood. Here, biochemical and structural analyses of the Numb·14-3-3 complex revealed that Numb phosphorylation at both Ser(265) and Ser(284) is required for Numb's efficient interaction with 14-3-3. We also discovered that an RQFRF motif surrounding Ser(265) in Numb functions together with the canonical C-terminal DPF motif, required for Numb's interaction with α-adaptin, to form a stable complex with α-adaptin. Of note, we provide evidence that the phosphorylation-induced binding of 14-3-3 to Numb directly competes with the binding of α-adaptin to Numb. Our findings suggest a potential mechanism governing the dynamic assembly of Numb with α-adaptin or 14-3-3. This dual-site recognition of Numb by α-adaptin may have implications for other α-adaptin targets. We propose that the newly identified α-adaptin–binding site surrounding Ser(265) in Numb functions as a triggering mechanism for the dynamic dissociation of the Numb·α-adaptin complex.

In this work, epitaxial growth of Ge on Si is achieved using magnetron sputtering which is a low-cost and safe method suitable for large-scale production. Smooth surface with RMS roughness of 0.48 nm is obtained at a low deposition temperature of 300 °C. Cyclic thermal annealing is applied to the Ge film reducing the threading dislocation density (TDD) by two orders of magnitude. The in-plane strain in the Ge film changes from compressive to tensile after annealing due to the mismatch in thermal expansion coefficients between Si and Ge. The mechanism of the TDD reduction is investigated revealing formation of dislocation loops and dissociation of dislocations into planar defects at the interface. The Ge epitaxy film on Si may be suitable for use as virtual substrate for the fabrication of III–V high efficiency solar cells.

Aluminium-assisted crystallization is used to grow single-crystalline SixGe1−x film epitaxially on Si substrate at a relatively low temperature (350–450 °C). Investigation of the mechanism by which Al film causes epitaxial growth of SixGe1−x suggests a four-step growth process is involved. The composition of the SixGe1−x film can be controlled by the annealing conditions. This SixGe1−x film can be used as a buffer layer for the epitaxial growth of Ge on Si or as a virtual substrate for the fabrication of III–V devices.

Ge wafers have been employed as substrates for high efficiency III-V multi-junction solar cells because of the almost ideal lattice match. However, the cost of Ge wafers is high and the Ge bandgap is too small which limits its contribution to the overall voltage output. Since Si has much higher bandgap and lower cost than Ge, using epitaxial Ge on Si as virtual substrates for III-V material growth is a promising solution. However, the challenge is the high threading dislocation density (TDD) in the Ge layer generated by the large lattice mismatch (4%) between Ge and Si. Thermal annealing has been intensively investigated in order to reduce TDD in the Ge layer deposited on Si. Two-step low temperature — high temperature Ge deposition followed by thermal annealing and cycled epitaxial Ge growth and annealing have been studied using CVD systems. Compared with conventional thermal processes, the CW diode laser treatment offers a fast and low-cost alternative to effectively reduce the TDD in Ge films. By laser scanning the sample, the Ge layer can be melted and recrystallized. After the laser treatment, the TDD of Ge films can be reduced by three orders of magnitude to 106 cm−2 which may be suitable for fabrication of III-V solar cells. Raman spectroscopy and Transmission Electron Microscopy measurements are employed to investigate the TDD reduction of the virtual Ge substrates.

A simple and novel DNA and gold nanoparticle (AuNPs) based colorimetric method has been developed for efficient detection of Deoxyribonuclease I (DNase-I) activity. For the detection process, the sample that contains DNase-I, which will cleave double stranded DNA into small pieces. Furthermore, the small pieces DNA sequences and water-soluble conjugated polymer cause the AuNPs aggregation (the solution change the color from red to blue). Thus, DNase-I could be detected by naked eyes or UV/Vis. Molecular substrates can be viewed as computational devices that process physical or chemical ‘inputs’ to generate ‘outputs’ based on a set of logical operators. Based on the assay, we have presented a DNA/AuNP based, multi-readout AND logic operations.

Hydrogenated polycrystalline SixGe1−x films, with a varying silicon fraction x ≤ 0.246, were in situ deposited in an argon and hydrogen mixture at 500 °C using radio frequency sputtering with an aim to develop a material for the bottom cell of a low cost monolithic tandem solar cell. Silicon and germanium atomic compositions of the films were determined by X-ray photoelectron spectroscopy (XPS). Structural evolution revealed by Raman and X-ray diffraction (XRD) indicated that the crystallinity of the films was improved with decreasing silicon fraction, accompanied with an increase of surface roughness verified by atomic force microscopy (AFM). Optical band gaps of these films derived from Tauc plots, which were calculated from reflectance/transmittance measurements, decreased with decreasing silicon fraction. Resistivity of the films, determined by four-point-probe technique, significantly decreased as well. High quality with low thermal budget obtained in this work suggests the films could be used in thin film solar cells on glass.

Secondary phases are likely to occur in the Cu2ZnSnS4 (CZTS) films since the CZTS is thermodynamically stable in only a narrow region of the phase diagram. The CZTS solar cell performance can be influenced by the existence and precipitated position of secondary phases. Therefore, locally investigate the distribution of secondary phases is important to further improve CZTS solar cell efficiency. In this study, two different kinds of transmission electron microscopy imaging techniques, bright field scanning TEM image (BF-STEM) and High-angle annular dark-field (HAADF) image, are applied to analyze the distribution of secondary phases. Due to the atomic number differences between CZTS and secondary phases, secondary phases are evident in the HAADF images. Therefore, HAADF image is a more powerful and convenient method to analyze the secondary phases than the BF-STEM image.

In this work, one-step aluminium-assisted crystallization of Ge on Si is achieved via magnetron sputtering by applying an in-situ low temperature (50 °C to 150 °C) heat treatment in between Al and Ge depositions. The effect of heat treatment on film properties and the growth mechanism of Ge epitaxy on Si are studied via X-ray diffraction, Raman and transmission electron microscopy analyses. Compared with the conventional two-step process, the one-step aluminium-assisted crystallization requires much lower thermal budget and results in pure Ge epitaxial layer, which may be suitable for use as a virtual substrate for the fabrication of III-V solar cells.