Rechargeable magnesium batteries have attracted considerable attention because of their potential high energy density and low cost. However, their development has been severely hindered because of ...the lack of appropriate cathode materials. Here we report a rechargeable magnesium/iodine battery, in which the soluble iodine reacts with Mg
to form a soluble intermediate and then an insoluble final product magnesium iodide. The liquid-solid two-phase reaction pathway circumvents solid-state Mg
diffusion and ensures a large interfacial reaction area, leading to fast reaction kinetics and high reaction reversibility. As a result, the rechargeable magnesium/iodine battery shows a better rate capability (180 mAh g
at 0.5 C and 140 mAh g
at 1 C) and a higher energy density (∼400 Wh kg
) than all other reported rechargeable magnesium batteries using intercalation cathodes. This study demonstrates that the liquid-solid two-phase reaction mechanism is promising in addressing the kinetic limitation of rechargeable magnesium batteries.
Silicon has been perceived as one of the most promising anodes in the next generation lithium-ion batteries (LIBs) due to its superior theoretical capacity. However, bulk silicon experiences an ...enormous volume expansion during the lithiation/delithiation process, resulting in rapid capacity fading. And, its high-cost and low coulombic efficiency also present significant challenges for applications. Here, we presented a facile and large-scale approach for preparing micro-sized porous silicon by acid etching the abundant and inexpensive metallurgical Fe-Si alloy as a high-performance anode in LIBs. Profiting from the unique micro-sized structure, it exhibited a fantastic first-cycle coulombic efficiency of 88.1% and an excellent reversible capacity of 1250 mA h g super(-1) at 500 mA g super(-1) after 100 cycles. Furthermore, the micro-sized porous silicon without carbon coating could deliver a reversible capacity of 558 mA h g super(-1) at a high current density of 5 A g super(-1) due to the unique porous structure. This work provides a promising route for a large-scale production of high-performance micro-sized Si as anode materials in LIBs.
Crystallization behavior of polylactic acid (PLA) under CO2 is meaningful due to its effect on foaming behavior during CO2 foaming, while present studies mainly concentrated on overall ...crystallization behavior. In this study, the effect of CO2 on nucleation and spherulite growth of PLA crystals was in situ investigated separately. During saturation, sorption of CO2 in PLA diluted the molecular chain density, thus increasing molecular chain mobility and weakening the interchain interaction, which reduced the amount of crystal nuclei in PLA. On the other hand, the spherulite growth rate reduced at high temperature and increased at low temperature attributed to the enhanced chain mobility under CO2. Thus, overall crystallization was controlled by the spherulite growth rate at low temperature and crystalline nucleation at high temperature under CO2. Besides, CO2 restricted lamella branching, resulting in an increased lamella thickness and z axis size. Current results revealed the effect of tunable molecular chain mobility and the interchain interaction adjusted by CO2 on nucleation and spherulite growth of PLA.
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IJS, KILJ, NUK, PNG, UL, UM
In infrared weak target detection systems, high-frequency vibrating mirrors (VMs) are a core component. The dynamic surface shape of the VM has a direct impact on imaging quality and the optical ...modulation effect, so its measurement is necessary but also very difficult. Measurement of the dynamic surface shape of VMs requires a transiently acquired image series, but traditional methods cannot perform this task, as, when the VM is vibrating at a frequency of 3033 Hz, using high-speed cameras to acquire the images would result in frame rates exceeding 1.34 MFPS, which is currently technically impossible. In this paper, we propose the long exposure short pulse synchronous phase lock (LSPL) method, which can capture the dynamic surface shape using a camera working at 10 FPS. In addition, our proposed approach uses a single laser pulse and can achieve the dynamic surface shape measurement on a single frame image.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A true random coded photon counting Lidar system is proposed in this paper, in which a single photon detector acts as the true random sequence signal generator instead of the traditional function ...generator. Compared with the traditional pseudo-random coded method, the true random coded method not only improves the anti-crosstalk capability of the system, but more importantly, it effectively overcomes the adverse effect of the detector’s dead time on the ranging performance. The experiment results show that the ranging performance of the true random coded method is obviously better than that of the pseudo-random coded method. As a result, a three-dimensional scanning imaging of a model car is completed by the true random coded method.
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FFLJ, NUK, ODKLJ, UL, UM, UPUK
Graphene-like BN nanosheets were synthesized
via
carbon-substitution reaction using graphene as a template in an attempt to produce C-doped BN. The carbon residue was removed by high-temperature ...oxidation in air. The role of the graphene template and oxygen with regard to the local structure of BN and its defect-related optical luminescence are investigated using X-ray absorption near-edge structure (XANES) and X-ray excited optical luminescence (XEOL). The structure and bonding of B, N, C and O in different chemical environments before and after oxidation are revealed by XANES. It is found that B and N atoms tend to form large BN domains, whereas the formation of B-C or N-C bonding is not significant. Two types of O local structures are found under different oxidation temperatures, as revealed by XANES: moderate oxidation results in O substituting N, while B
2
O
3
-like local structure is formed under higher oxidation temperature. The two types of O-related defects exhibit different luminescence properties.
Under different temperatures, O atoms form either dopant or B
2
O
3
domains, which result in different luminescence behaviors of BN nanosheets.
To obtain the dynamic surface of high-frequency vibrating mirrors (VMs), a novel method involving multi-field interference (MFI) pattern imaging on a single image is proposed in this paper. Using ...multiple reflections and refractions, the proposed method generates three interference patterns at the same time, which improves the traditional time-series methods where a single interference pattern can be obtained at one time. Experimental results show that a series of MFI patterns can be obtained on a single image, with the laser repetition frequency (LRF) ranging from 200 Hz to 10 Hz, and the frame rate of the camera at 10 Hz. Particularly if the LRF (10 Hz) is equal to the frame rate of image, crosstalk is avoided completely, which is particularly desirable in dynamic surface measurement. In summary, the MFI imaging method provides an effective way for VM dynamic surface measurement.
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Bio‐based polymer materials are considered to have function of protecting the environment, and improving the degradation performance of bio‐based polymer materials is of great significance to realize ...the green cycle of production‐use‐degradation of plastic products. This present work is focused on the investigation of the degradation behavior of bio‐based polymer blend poly(ethylene 2,5‐furandicarboxylate) /polyglycolide acid (PEF/PGA) with different composition ratios in phosphate‐buffered saline (PBS solution, pH = 7.4) with 0.5 mg/mL of lipase from porcine pancreas. The results observed that the thermal decomposition temperatures at 5% weight loss of both the PEF/PGA blends are higher than 310°C, which reflected that the PEF/PGA blends possessed excellent thermal stability. The water absorption of the PEF/PGA blends continued to increase with increasing the PGA content. This trend is consistent with the mass loss of blends in the degradation process. The systematic degradation study revealed that the neat PEF showed no mass loss in both PBS solution with and without lipase, while the PEF/PGA blends possessed a faster rate under enzymatic degradation circumstance in the first 4 weeks, and the weight loss in the same degradation period increase with increasing the PGA content due to the erosion of lipase on the polymer chain. In particular, the weight loss of PEFGA40 blend was more than 18.33% after 8 weeks of degradation in enzyme solution. 1H NMR results showed that in addition to PGA component as a major component of degradation, a small amount of PEF component was also involved in the mass loss of the blend during degradation. At the same time, the short‐chain segment produced during the degradation had a clear plasticizing effect on the PEFGA blends, which is reflected in that the Tg of PEFGA40 blend decreased first and then increased with the increase of degradation time.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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