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It was precisely because LiNi${}_{0.5}$Mn${}_{1.5}$O₄ cathode material had many advantages, including high voltage, high power, no pollution, low cost, etc., that it became a research hotspot for lithium-ion cathode materials. Although LiNi${}_{0.5}$Mn${}_{1.5}$O₄ has a three-dimensional Li${}^{+}$ diffusion channel, there are still some problems that lead to capacity decay and reduced cycling stability, limiting its commercial application. In this paper, the LiNi${}_{0.5}$Mn${}_{1.5}$O₄ cathode material was prepared by the freezing precipitation method. We studied the effects of different drying methods, such as blast drying, water bath drying and freeze-drying on the structure, morphology and electrochemical properties of LiNi${}_{0.5}$Mn${}_{1.5}$O₄ cathode materials. The study found that the LiNi${}_{0.5}$Mn${}_{1.5}$O₄ cathode material prepared by the precipitation-freeze-drying method had a complete crystal form, a stable structure and no Li_xNi${}_{1-x}$O impurity peak. The SEM image showed that the particles were smaller and had a smooth surface. The initial discharge-specific capacity at 0.1C was 105.2mAh⋅g${}^{-1}$. After 50 cycles, its specific discharge capacity was 99.4mAh⋅g${}^{-1}$ and the capacity retention rate was 94.5%. Compared with LiNi${}_{0.5}$Mn${}_{1.5}$O₄ materials prepared by other methods, it had better electrochemical performance.

The sonication processing was added in front of the freeze-drying as an intermediate processing before the molybdenum disulfide (MoS₂) aerogel was synthesized. It is distinguishing with the traditional hydrothermal reaction to combine the sonication processing and freeze-drying in our method. The structure, morphology, specific surface area and pore size distribution were characterized, and the electrochemical performances were measured in 0.5M Na₂SO₄ electrolyte for the MoS₂ aerogel and flower-like MoS₂. As for comparison, they are of porous structure and microsphere structure, and their specific surface areas are 55.14m²g${}^{-1}$ and 38.12m²g${}^{-1}$. The specific capacitances are 166.7Fg${}^{-1}$ and 119.2Fg${}^{-1}$ at the scan rate of 5mVs${}^{-1}$, and the capacity retentions are 87.7% and 81.6% after 3000 charge/discharge cycles. For the enhanced mechanism, the high specific surface of the MoS₂ aerogel causes high specific capacitance, and the unique porous structure could buffer volume expansion to improve retention ability during charge/discharge processes. The MoS₂ aerogel may thus be a promising electrode material for supercapacitors.

Novel synthesis of efficient noble-metal-free electrocatalysts for both oxygen reduction/evolution reaction (ORR/OER) in energy conversion devices (e.g., fuel cells, metal–air batteries) is of essential significance for further sustainable development. This paper reports a facile synthesis of Fe–N–C species-modified carbon nanotubes (F/N-CNTs) for ORR application by directly pyrolyzing a fluffy hybrid precursor at a moderate temperature ($\sim 900^{\circ }$C) in Ar. The fluffy hybrid precursors consisting of nitro-hydrochloric-acid-treated CNTs, melamine and Fe${}^{3+}$ species are prepared via a freeze-drying method. On account of the synergistic effect of various active sites, including pyridine–N, Fe–N_x and Fe₃C, and the high conductivity of the CNTs matrix, the as-obtained F/N-CNT electrocatalysts exhibit excellent ORR activities, comparable to commercial Pt/C. The addition of N heteroatoms, the dosage of Fe and the pyrolysis temperature highly influence the ORR properties of the F/N-CNT samples. The typical F/N-CNT sample obtained at the optimized parameters shows an onset potential of 1.06V and a half-wave potential of 0.91V versus reversible hydrogen electrode (RHE) in an alkaline condition, more positive than those (1.01V and 0.88V versus RHE) of Pt/C. The F/N-CNT exhibits outstanding bifunctional ORR/OER activity and excellent methanol tolerance, and the F/N-CNT-based Zn–air battery (ZAB) with an open-circuit voltage (OCV) of 1.405V presents a current density of 125mAcm${}^{-2}$ and a power density of 76.5mWcm${}^{-2}$; these electrocatalytic properties are highly superior to Pt/C. The direct pyrolysis of fluffy hybrid precursors provides a concise but robust technical platform to achieve high-performance noble-metal-free electrocatalysts with ORR/OER activities superior to Pt/C.

As an important process analysis tool, near infrared spectroscopy (NIRS) has been widely used in process monitoring. In the present work, the feasibility of NIRS for monitoring the moisture content of human coagulation factor VIII (FVIII) in freeze-drying process was investigated. A partial least squares regression (PLS-R) model for moisture content determination was built with 88 samples. Different pre-processing methods were explored, and the best method found was standard normal variate (SNV) transformation combined with 1st derivation with Savitzky–Golay (SG) 15 point smoothing. Then, four different variable selection methods, including uninformative variable elimination (UVE), interval partial least squares regression (iPLS), competitive adaptive reweighted sampling (CARS) and manual method, were compared for eliminating irrelevant variables, and iPLS was chosen as the best variable selection method. The correlation coefficient (R), correlation coefficient of calibration set (R_cal), correlation coefficient of validation set (R_val), root mean square errors of cross-validation (RMSECV) and root mean square errors of prediction (RMSEP) of PLS model were 0.9284, 0.9463, 0.8890, 0.4986% and 0.4514%, respectively. The results showed that the model for moisture content determination has a wide range, good linearity, accuracy and precision. The developed approach was demonstrated to be a potential for monitoring the moisture content of FVIII in freeze-drying process.

${\mathrm{\text{TiO}}}_2$/C aerogel composites are primarily composed of resorcinol-formaldehyde (RF) and low-cost commercial titanium dioxide nanoparticles. These composites are synthesized through a simple process of freeze-drying and high-temperature carbonization under inert gas protection. ${\mathrm{\text{TiO}}}_2$ nanoparticles in the ${\mathrm{\text{TiO}}}_2$/C aerogel composites produce partial oxygen vacancies by high-temperature treatment under anoxic conditions which is beneficial to increase the carrier density of the material. Electrochemical characterizations confirm the excellent specific capacitance, which reaches a maximum of 250 F ${\mathrm{\text{g}}}^{-1}$ at a current density of 0.2 A ${\mathrm{\text{g}}}^{-1}$. Moreover, after 5000 charge/discharge cycles at a current density of 10 A ${\mathrm{\text{g}}}^{-1}$, capacitance retention can be up to 98% or more. These properties are attributed to a synergistic effect of electrical double layer capacitance and pseudo-capacitance.

The influence of drying parameters of freeze-drying on quality of Pteridium Aquilinum drying was investigate, and the impact of drying board temperature, drying chamber pressure and material thickness on vitamin C content was studied by nonlinear regressional orthogonal design. Using single and double factor analysis method, the relation between experimental criteria and drying parameters was established, and the influence order of the parameters was determined. Experimental results showed that drying chamber pressure had the greatest influence than drying board temperature and material thickness. The optimal combination of the preserved quality parameters for the freeze-drying technology of Peridium aquilium was obtained through optimized theory in nonlinear method. They are as follows: the pressure of drying chamber is 55Pa, the temperature of the board is 42.5°C, and material thickness is 16.3mm.

Porous silica xerogel materials are one of the well-known materials for versatile applications. Nowadays, high production cost related to exorbitant precursors and tim-econsuming/high risk modification-traditional drying process has often narrowed the wide-spread applications. Exploitable facile strategy for easy fabrication and maintaining the exotic performances of the material is a key for future promotion of such exotic materials. In this work, water glass aqueous solutions with varied concentrations of SiO₂ has been used as the precursor. The silica hydrogels were exchanged the pore solvent of water to t-butanol, followed freeze-drying of the wetgel. The final cryogel products maintain the most of the mesoporous structures. The morphology and the porous structures of the gels were analyzed by the TEM and BET, which was correlated to the performance evaluation of thermal conductivity. Lightweight (0.06 – 0.30 g/cm³) and high surface area (490 – 910m²/g) cryogels were prepared by using such route. They display an porous structure with 80 - 97% porosity and versatile morphologies, the materials maintain a promising thermal conductivity of 0.2 W m^-1K^-1. This study offers an alternative route for the synthesis of porous silica gel via traditional sol-gel process.