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The multicolor-based point-of-care testing (POCT) of tumor cell-derived exosomes is of vital importance for understanding tumor growth and metastasis. Multicolor-based ratiometric signals most often rely on molecular optics, such as fluorescence resonance energy transfer (FRET)-dependent molecular fluorescence and localized surface plasmon resonance (LSPR)-related molecular colorimetry. However, finding acceptable FRET donor-acceptor fluorophore pairs and the kinetically slow color responses during size-related molecular colorimetry have greatly impeded POCT applications. Herein, an atomic flame was used to develop a visual sensing platform for the POCT of tumor-cell-derived exosomes. In comparison with common molecular optics, the atomic flame possessed the advantages of providing both a variety of ratiometric flame signals and fast response sensitivity. The integration of a gas-pressure-assisted flame reaction and dual-aptamer recognition guaranteed the sensitive and selective analysis of exosomes with a low limit of detection (LOD) of 7.6 × 102 particles per mL. Such a novel optical signal will inspire the development of more user-friendly POCT approaches.

The stearic acid (SA) – hexanamide (HA) binary mixtures were prepared, and the phase diagram and Tammann plot were constructed. The differential scanning calorimetry results indicated that a eutectic composition formed by 46.2 mol% SA and 53.8 mol% HA melted at the temperature of 331.15 K with a latent heat of 176.62 J·g−1. Fourier transform infrared spectroscopy and X-ray diffraction results revealed that SA and HA were just physical mixture. The results of thermogravimetric analysis and 100 thermal cycles test respectively manifested that eutectic mixture had good thermal stability and reliability. Therefore, eutectic mixture is promising for thermal energy storage application.

A series of stearic acid (SA)/benzamide (BA) binary mixtures were prepared and demonstrated, and then the phase diagram and Tammann plot were established. The results showed that the molar fraction of SA in SA-BA eutectic mixture was 0.757. The eutectic mixture melted at 339.05 K with 200.15 J·g−1 latent heat. Expanded graphite (EG) was added to eutectic mixture to form composite phase change materials (PCMs) owing to the eutectic mixture has low thermal conductivity. It was found that the binary mixture and EG had good chemical compatibility, and the thermal conductivity of the composite with 12 wt% EG was significant increased by 12.30 times compared to eutectic mixture. Besides, the phase change properties of eutectic mixture/12 wt% EG composite phase change material (PCM) had a little change after 100 thermal cycles, and had negligible mass loss after leakage test. These results demonstrated that the composite PCM had good thermal reliability and stability. Based on the above results, the composite PCM has great potential in thermal energy storage application.

Kinetics of rubidium extraction by 4-tert-butyl-2-(α-methylbenzy) phenol (t-BAMBP)/sulfonated kerosene in brine solutions were investigated using the rising single drop technique. Parameters affecting the mass transfer mechanism, including the interfacial area, initial alkalinity of aqueous phase, concentration of rubidium ions and t-BAMBP, and temperature were studied. The results indicated that the process of extraction was controlled by the diffusion process, while the chemical reaction occurred at the interfacial area. Dynamic equation of the extraction system, Re = 2.901 × 10−5[Rb+]1.022[OH−]1.179[t-BAMBP]0.991 was obtained by non-linear fitting the experimental data. Moreover, a new mechanism of the rubidium extraction with t-BAMBP/sulfonated kerosene was proposed.

The thermal properties of the binary system composed of lauric acid (LA) and nonanoic acid (NA) and its binary phase diagram were studied. To put this binary system into practice, the mixture with 96wt% of LA was selected, and it has a phase change temperature of 41oC and a latent heat of 163 J g-1, which is suitable for domestic water heating application. Besides, its thermal and chemical structure stability, thermal conductivity, degree of supercooling and thermal reliability were investigated by thermogravimetric analyzer (TGA), fourier transform infrared (FT-IR) spectrophotometer, thermal conductivity apparatus (TCA), T-history method and accelerated thermal cycle test for 1000 melt/freeze cycles, separately. The results of above tests indicated that the mixture has a remarkable thermal stability, a good chemical structure stability, no supercooling and an excellent thermal reliability. Therefore, the mixture can be a potential PCM used for thermal energy storage.

The thermal properties of caprylic acid, nonanoic acid and their binary system were investigated by differential scanning calorimetry (DSC). The phase diagram for the binary system was constructed, and the experiment results showed that the eutectic temperature and the molar fraction of caprylic acid for the eutectic mixture are 1.83 °C and 0.483, respectively. To satisfy the application demands of the temperature scope from 5 °C to 15 °C, another binary mixture for the binary system with a molar fraction of 0.814 for caprylic acid component is found successfully, and it has good thermal properties that the melting temperature and the latent heat are 7.6 °C and 123 J g−1, respectively. What is more, the latent heat and melting temperature for the binary mixture do not change at all nearly after being cycled 100 times during the whole melting process. As a novel phase change material (PCM) for application in the field of air conditioning and cooling, the binary mixture has own unique thermal advantages.

Shape-stabilized composite phase change materials composed of sebacic acid (SA) and MCM-41 were prepared by a facile blending and impregnating method. Various characterization techniques were carried out to characterize their structural and thermal properties, including thermogravimetry (TG) analyses and differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy. The XRD and FT-IR results indicated the interactions between SA and MCM-41, such as the capillary force and the hydrogen bonding, resulting in the confined crystallization process. As a result, the SA that was confined was amorphous. The TG analysis results showed that the presence of MCM-41 practically resulted in an overlapping of the two decomposition stages. The DSC analysis demonstrated that a decrease in the SA content was accompanied by a continuous decrease in the melting point and phase change enthalpy of the composites.

An adipic acid/boric acid (AA–BA) binary eutectic mixture containing 80 wt % adipic acid and 20 wt % boric acid was investigated as a new phase change material (PCM) with high latent heat, high thermal stability, and low cost. The material′s thermophysical properties and thermal stability were studied using differential scanning calorimetry (DSC), X-Ray Diffraction (XRD), and thermogravimetric analysis (TGA). The thermal stability was investigated in situ over 100 cycles using DSC. The phase change temperature of the AA–BA binary eutectic mixture was 135.04 °C and the latent heats of the melting and crystallization process were 283.42 and 272.16 J g−1, respectively. The latent heat of melting only dropped 4.94 % after in situ 100 cycles using DSC. Following comparison of thermal properties and price of the AA–BA eutectic mixture PCM with those of some composite PCMs, the results indicate that the newly prepared AA–BA eutectic mixture is a potential phase change material for thermal storage tanks.

We investigated the thermal properties and thermal reliability of stearic acid- n -butyramide and stearic acid- n -octanamide binary eutectic mixtures, as phase change materials for low temperature solar heat energy storage. The solid-liquid phase diagrams of two binary systems were established, and the eutectic compositions of binary mixtures and corresponding thermal properties were verified: (1) stearic acid- n -butyramide, the eutectic composition is 0.551 ± 0.005 mol fraction stearic acid and (2) stearic acid- n -octanamide, the eutectic composition is 0.589 ± 0.005 mol fraction stearic acid. The eutectic compositions have high latent heat of fusion Δ H m = 198.38 ± 10.22 J·g −1 , Δ H m = 198.98 ± 8.56 J·g −1 and melting temperature T peak = 337.41 ± 1.93 K, T peak = 336.28 ± 2.00 K for stearic acid- n -butyramide and stearic acid- n -octanamide binary mixture, respectively. A modeling approach on the bases of thermodynamics is employed to predict solid-liquid equilibria of the studied mixtures and their latent heats of fusion. The simulated results are in good agreement with experimental results. The heat capacity of the solid phase measured are 1.69 ± 0.2 J·g −1 ·K −1 , 1.61 ± 0.2 J·g −1 ·K −1 and the thermal conductivity of the solid phase are 0.222 ± 0.03 W·m −1 ·K −1 , 0.276 ± 0.034 W·m −1 ·K −1 at 298.15 K for stearic acid- n -butyramide and stearic acid- n -octanamide binary mixture, respectively. The mixture has a good thermal stability after 100 melt-freeze cycles. As novel phase change materials for solar heat applications, the studied eutectic mixtures have attractive thermal performance and great utility.

To propel the commercialization of fuel cells, the development of efficient nonprecious metal catalysts, specifically cathodic oxygen reduction catalysts, is turning into reality because the great advancements have been made on nitrogen-doped carbon materials recently. In this study, we demonstrated that nitrogen-doped hollow carbon nanoparticles (N-HCNPs) exhibit excellent electrocatalytic performance for oxygen reduction reaction (ORR) in alkaline fuel cells. Cyclic voltammetry and rotating ring-disk electrode voltammetry showed that the ORR activity of N-HCNPs approaches that of commercial Pt–C catalyst and is much better compared with nitrogen-free counterparts due to the incorporation of nitrogen atoms into graphitic structures. Kinetic studies indicated that the involvement of nitrogen induces a totally different oxygen adsorption mechanism and a four-electron dominated reaction pathway for N-HCNPs in comparison with nitrogen-free HCNPs, very similar to the observations in Pt–C. Moreover, N-HCNPs ex...

Graphene was synthesized by the detonation-assisted reduction of graphite oxide (GO) prepared by the modified Hummers method. Nitrogen-doped reduced GO (N-RGO) was obtained through an in situ nitrogen-doping during detonation. The morphology, elemental composition and structure of the N-RGO were characterized by TEM, SEM, IR, XPS, XRD and Raman spectroscopy. The catalytic activity of the N-RGO as a fuel cell electrode for the oxygen reduction reaction (ORR) was investigated by a rotating ring disk electrode technique. Results showed that the GO was exfoliated and reduced to few layer graphene by the detonation. The oxygen-containing species of GO were reduced and the C/O molar ratio was increased to 26.2, which is much higher than for RGO. Nitrogen, as high as 2.11 at.%, was incorporated into the graphene structure. The diffusion-limited current for ORR increased from 0.24 mA for RGO to 0.49 mA for N-RGO, indicating a higher catalytic activity of N-RGO for ORR than that of RGO.

The non-equilibrium quick oxidation of titanium nitride (TiN) particles is found to be capable of kinetically controlling the partial oxidation on the surface and constructing a TiOxNy@TiN core–shell structure, in which the TiOxNy shell exhibits different components (x = 0.0–2.0). The TiOxNy@TiN structure can absorb visible light and display a high photocatalytic activity for hydrogen production, without any help from noble metal co-catalysts. A hydrogen generation rate of 506 μmol g−1 h−1 can be reached. The strong catalytic ability of TiOxNy@TiN can be attributed to the formation of heterojunction among the hybrid TiOxNy, which can facilitate the separation of light-induced electron–hole pairs. Furthermore, the non-equilibrium quick oxidation leads to the partial survival of electro-conductive TiN tiny crystals on the surface, which can act as co-catalysts to further improve the electron–hole separation and to catalyze hydrogen ion reduction.