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The large-scale and efficient synthesis of MnPO4·H2O is an urgent problem to be solved. In this paper, self-assembled dumbbell-shaped MnPO4·H2O particles were successfully synthesized just using KMnO4 and commercial concentrated H3PO4, and then employed as the precursor to prepare LiMnPO4/C composites. The XRD, SEM, TEM, and electrochemical performance tests were used to investigate MnPO4·H2O and the corresponding LiMnPO4/C. The formation mechanism of MnPO4·H2O was discussed. The results showed that temperature and water content have a significant effect on the yield, purity, and morphology of MnPO4·H2O. The synthesized LiMnPO4/C with reduced carbon content at 650 °C delivered a discharge capacity of 109.3 mA h g-1 at 1 C and 104.3 mA h g-1 at 2 C. This green and efficient synthesis method of MnPO4·H2O provides a new idea for the large-scale preparation of LiMnPO4/C cathode materials.

There is a pressing need around the world to develop novel functional biodegradable materials to separate oil/water mixtures and emulsions completely. Recently, superhydrophilicity and underwater superoleophobicity materials have been attracted attention due to their high efficiency in oil/water separation. However, it is still a challenge to prepare materials that combine oil/water separation and water purification in an environment-friendly way. In this work, biodegradable starch-based nanospheres (SNPs) coated filter paper was prepared in a low-cost, simple, and environmentally friendly manner. The SNPs coating could not only help to change the wettability of the substrate material but also build the hierarchical micro and nano structures which are conducive to separation and purification process. After modification by coating SNPs, the filter paper exhibited excellent performance in a wide range of oil/water mixtures or emulsions separation and the wettability of the filter paper could be regulated by adjusting the pH value. The modified filter paper presented good recyclability after several separation process. Furthermore, the as-prepared filter paper could also remove water-soluble contaminants during the oil/water separation process, thus realizing to combine separation and purification process in one single step. This biodegradable starch-based separating material with good separation performance, stability and recyclability has significant application potential in practical separation and purification process.

Ni-rich LiNi0.8 Co0.15 Al0.05 O2 (NCA) material attracts extensive attention due to its high discharge specific capacity, but its distinct drawbacks of rapid capacity decline and poor cycle performance at elevated temperatures and high voltage during charge/discharge cycling restricts its widespread application. To solve these problems, a multifunctional coating layer composed of a lithium-ion-conductive lithium polyacrylate (LiPAA) inner layer and a cross-linked polymer outer layer from certain organic substances of silane-coupling agent (KH550) and polyacrylic acid (PAA) is successfully designed on the surface of NCA materials, which is favorable for eliminating residual lithium and improving lithium-ion conductivity, surface stability, and hydrophobicity of NCA materials. In addition, the amount of the coating material is also investigated. A series of characterization methods such as XRD, FTIR, SEM, TEM, and X-ray photoelectron spectroscopy are used to analyze the morphologies and structures for materials of pristine and modified NCA. It is revealed that the co-coating layer plays a vital part in reducing the surface residual alkalis and improving the stability of NCA particles; as a result, the modified NCA exhibits a greatly improved rate capability, cycle performance, and low polarization impedance.

Pickering high internal phase emulsions (HIPEs) stabilized solely by bioderived starch-based particles hold potential for application in the food and pharmaceutical fields. This paper reports the use of a thermoresponsive 2-hydroxy-3-butoxypropyl starch (HBPS) particle as a representative natural biocompatible material for use as an effective stabilizer for HIPE formation. HBPS is synthesized by using butyl glycidyl ether as a hydrophobic reagent to change the hydrophobic–hydrophilic balance of starch, and then starch-based particles are fabricated by a simple nanoprecipitation procedure. The size of particles increased with an increase in temperature, and the particles are essentially monodisperse with a PDI of about 0.1 when the temperature was above 15 °C. These HBPS particles were subsequently used as an effective stabilizer to fabricate stable oil-in-water (o/w) Pickering HIPEs with an internal phase volume of 80% at different stabilizer concentrations. The results demonstrated that increasing the particle concentration is conducive to the formation of stable Pickering HIPEs with greater stiffnesses. In addition, the nutraceutical material (β-carotene) was encapsulated into HIPEs and in vitro release experiments revealed that the release in this system can be controlled by adjusting the temperature.

Using different products of disc thickness and Yb ions concentration, we report on the laser performance of Yb:YAG crystals under room and cryogenic temperatures. The optimum crystal parameters have been realized. With a thickness of 0.8 mm, 15 at. % Yb ions doping concentration laser crystal, high optical to optical efficiency of 85.2% and slope efficiency of 89.0% have been achieved and the maximum output energy was 75.6 mJ at ∼ 80 K. Furthermore, the wavelength-switching phenomenon was observed owing to a lower loss cavity with the temperature reduction. Calculation results from the model based on the rate equations were well consistent with the laser output performance. The wavelength-switching effect was also explained by this model.

To realize intelligent and low-cost protective materials, the development of compounds with smart stress-responsive properties and self-healing abilities over a wide temperature range is a major research goal. In this study, a series of impact hardening polymers (IHPs) with stress-responsive properties and self-healing ability in low temperature were synthesized via the condensation copolymerization of silicone polymers with various chain lengths and boron contents. The results of rheological analysis indicate that the IHPs have self-healing ability at low temperatures (healing times of less than 30 h and healing efficiencies better than 80% at −25 °C). Moreover, the relative shear stiffening effect (RSTe), which describes the stress-responsive ability of the IHP, exceeded 2000. In addition, the self-healing mechanism of IHP was investigated by Fourier transform infrared spectroscopy microscopy and pulsed 1H-NMR measurements. The results suggested that reversible dynamic cross-linking arising from the boron compound and the reduction in the threshold entanglement density owing to the longer length of the flexible polymeric backbone is crucial to impart low-temperature self-healing ability and stress-responsive properties to IHP.

The effects of transient temperature variation of gain medium on quasi-three-level microchip laser were investigated. Firstly, the dynamic behavior with temperature variation and the characteristic of the output power were reported. The numerical simulation results revealed not only the dynamics characteristic of lasing levels, but also the relationship between pump pulse width and output power in equivalent duty cycle. The increments of output power deviated significantly from linear increasing with the pump pulse width. The characteristic of the output power with different duty cycle was compared. Because the heat load was rising with the increase of the duty cycle and high heat load reduced population inversion density, the optical-to-optical efficiency of 9.7% at 50% duty cycle was lower than optical-to-optical efficiency of 15.6% at 7% duty cycle. The calculated and experimental pump power thresholds for output of 1030 nm were discussed. Particularly, the output power calculated by the model with the addition of temperature terms was significantly lower than that simulated by the model without temperature terms. Experimental results have shown a good agreement with the theoretical predictions.

A green strategy is designed for synthesizing LiMn0.8Fe0.2PO4/C composites bases on mechano-chemical liquid-phase activation technique. The micro-nano spherical precursor is prepared by the effective redox reaction between MnO2 and H2O2 in H3PO4 aqueous solution with subsequent addition FeC2O4•2H2O and Li2CO3, which is followed by spray drying. The dense LiMn0.8Fe0.2PO4/C microspheres are formed from conformal carbon coating connected with primary nano-sized particles, which provides rapid electron and ion transport pathways during the electrode reaction. The obtained LiMn0.8Fe0.2PO4/C cathode exhibits reduced electrochemical polarization with high voltage platform and high discharge capacity of 159 mAh g −1 at 0.1 C. Even at high rate of 10 C, the composite shows an impressing discharge capacity of 130 mAh g −1 with obviously stable plateau. Besides, uniformly conductive carbon network distributed all over the primary nano-sized particles effectively inhibits the occurrence of interfacial side reactions during electrode cycling, and the electrode exhibits good cycling stability with capacity retention rate of 95% after 500 cycles at 1 C. This work provides a scalable route to fabricate high energy density LiMn0.8Fe0.2PO4/C cathode with excellent rate performance for Li-ion battery.

We study biosourced core-shell particles with a starch-based core and thermo-responsive polymer brush shell using surface-initiated single-electron transfer living radical polymerization (SI-SET-LRP) as a Pickering stabilizer. The shell endows the Pickering stabilizer with reversible emulsification/demulsification of oil and water properties. The initiator attached to the starch-based nanosphere (Br-SNP) core particle was first fabricated using the precipitation method. Subsequently, dense poly( N-isopropylacrylamide) (PNIPAM) brush graft-modified starch-based nanoparticles (SNP- g-PNIPAM) were obtained via the SI-SET-LRP process. Interfacial properties of the resultant particles were analyzed by interfacial tensiometer measurements, as were the effects of the grafted polymer chain length and temperature on the interfacial activity. Pickering emulsion was obtained using SNP- g-PNIPAM particles as the stabilizer. The effect of the concentration of the Pickering stabilizer on the size of emulsion droplets was analyzed. The emulsification/demulsification process of the Pickering emulsion can be reversed and easily repeated by changing the temperature.

We have demonstrated a high peak power electro-optically cavity-dumped (CD) laser and a high energy picosecond regenerative amplifier (RGA) at 1342 nm. Their output power, pulse energy, pulse widths, and peak power were reported, respectively. For CD operation, the maximum pulse energy was 0.308 mJ at 1 kHz with the pulse width of 23.3 ns. The corresponding peak power was 13.2 kW. The maximum pulse energy of 0.243 mJ was extracted from RGA at 1 kHz under the seeded pulse energy of 250 pJ, resulting in its total optical gain of 9.7×105 . Its pulse width was estimated to be 43.8 ps, corresponding to a peak power of 5.55 MW.

Highly doped erbium crystals have complex fine energy levels, which can be used to emit lasers of different wavelengths under different conditions. The mid-infrared multi-wavelength laser of erbium ions has not yet achieved stable laser emission. In this study, the rate equation is used, with consideration of mode competition, to design a mid-infrared Er:YAG pulsed laser that emits four wavelengths at room temperature. The gain of the multi-wavelength erbium laser is related to the Boltzmann distribution coefficient. Based on this, the conditions for multi-wavelength output have been calculated and verified in experiments. A four-wavelength stable output mid-infrared pulsed laser based on Er:YAG was produced. This laser may be applied to remote sensing or gas detection.

A novel eco-friendly synthesis of LiFe0.25Mn0.75PO4/C@ reduced graphene oxide (rGO) was carried out. The effects of different grinding-drying process and reduced graphene oxide (rGO) modification on the morphology and electrochemical performance of the synthesized LiFe0.25Mn0.75PO4 materials were studied in detail. The studies show that the sanding assistant spray drying process can effectively refine the particle size of LiFe0.25Mn0.75PO4/C materials with uniform dispersion. The uniform nano size combination of rGO and carbon coating significantly reduce the charge-transfer impedance of electrode materials, and improve the conductivity and electrochemical properties of the materials. The optimization results show that LiFe0.25Mn0.75PO4/C@rGO materials display the most favorable kinetic behavior and the best electrochemical reversibility, with the specific discharge capacity of 143.8, and 139.8 mAh g−1 at 1 C and 2 C. After 100 cycles at 1 C, the capacity retention maintains 97.64%, showing a promising application prospect for lithium-ion batteries.

Conventional approaches to generating double emulsions are cumbersome, complicated, and based on a two-step emulsification process using a combination of two distinctive surfactants. In this work, the surface properties of diatomite particles were successfully tailored by chemical modification with palmitoyl chloride. The properties of the resulting diatomite particles changed from the original hydrophilicity to hydrophobicity, leading to straightforward stabilization of oil-in-water-in-oil (O/W/O) Pickering double emulsions by a one-step emulsification process. Pickering double high internal phase emulsions (HIPEs) with an internal phase up to 80 vol% could be produced solely using the modified diatomite particles. The water-in-oil (W/O) droplet sizes of these HIPEs were much larger than the droplets of conventional nanoparticle-stabilized Pickering HIPEs. Furthermore, using the O/W/O Pickering double emulsions as templates, the porous polymer particles were fabricated. In addition, it was demonstrated that the wide particle size distribution of diatomite particles and modified heterogeneity were the reasons for the formation of multiple emulsions.

We have established a new method for realizing a typical “2-color” collinear CARS (coherent anti-Stokes Raman scattering) system. The system mainly consists of a laser source, a D2O cell, and a spectrometer. The pump/probe beam and the Stokes beam are provided by SBS (stimulated Brillouin scattering) and BSRS (backward stimulated Raman scattering) of D2O, respectively. The CARS system is statistically stable, and it is also a broadband and alignment-free system. Measurement of N2 signal in air with this system is demonstrated. Detection of N2 in 0.006 bar air is realized with this system. Time-resolved pulse shapes of SBS and BSRS are measured to confirm their generation. Transference of energy from the SBS pulse to the BSRS pulse is realized with a Rhodamine 101 dye cuvette and discussed. This results in a better energy distribution between the pump/probe and Stokes pulses for CARS.

In this work, the anisotropy of nonlinear absorption in a crystal Q-switch was considered when we established coupled rate equations of a passively Q-switched laser. A [100]-cut Cr4+:YAG crystal, with initial transmission T0=40%, was used as the Q-switch to evaluate the theoretical model, and the results of the simulation were in good accordance with the experiment. In order to control timing jitter of the passively Q-switched laser, an actively Q-switched Nd:YAG laser was applied to directly bleach the [100]-cut Cr4+:YAG crystal. The timing jitter was more than 1 μs without bleaching light. While there was a bleaching light, the time lag between the laser pulse and the bleaching light was less than 100 ns, which meant the timing jitter decreased. The pulse width of the passively Q-switched laser was found to decrease from 45 to 35 ns due to the existing of bleaching light. As the peak power of bleaching light was increased, the laser pulse energy increased from 18.2 to 24.6 mJ, which meant a 35% increment in the pulse energy. The increase in pulse energy can be explained by the increase of α coefficient, and the results of simulation agreed well with the experiment.