We experimentally demonstrate the fabrication of a tellurite hollow core photonic crystal fiber (HC-PCF) which has a large hexagonal hollow core in the center. The fiber is successfully obtained by using rotational casting and rod-in-tube methods. The fiber diameter is about 160 µm, the diameter of the central hollow core is 19 µm and the thickness of the wall is 0.35 µm. A supercontinuum light source from 500 nm to more than 1500 nm is launched into the hollow core of a 7-cm-long fiber. The result shows that the transmission mode can be confined into the hollow core of the tellurite HC-PCF for the first time.

Hollow multi-walled carbon nanotubes (MWCNTs) were formed in situ by catalytic cracking of phenolic resin with addition of nano-manganese dioxide (nano-MnO₂) as a catalyst. The effects of catalyst content, coking temperature and heating rate on in situ growth of carbon nanotubes (CNTs) were investigated. The composition and microstructure were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and laser-raman spectrum. The results showed that nano-MnO₂ could catalyze phenolic resin to partly form MWCNTs inside of the materials, which transformed pyrolytic carbon structure and improved graphitization degree of the material after carbonization. With the increase of catalyst content, the length of CNTs decreased and the optimum addition amount was at 1.0 wt %. The higher the carbonization temperature, the bigger the activity of catalyst particles. The optimum growth temperature of CNTs was at 1200°C. At a higher heating rate, hydrocarbon molecules was hard to deposite on the surface of the catalyst particles to form CNTs. CNTs obtained at a heating rate of 2 °C/min possessed the highest degree of graphitization. The growth of carbon nanotubes was accordance with the mechanism of top growth.

Considering the same chemical compositions, the particle size of hydratable alumina (HA) is the key property related to the large differences in their rheology, sintering and thermal shock resistance. It is reasonable to consider that the benefits promoted by HA, added as binder, would be affected by particle size changes. In this study, the design of alumina-spinel castables is optimized based on changing particle size to control HA hydration behavior. It is observed that the pH values and conductivities of HA slurry raise with decreasing particle size which indicates an increase in hydration rate of HA. The finer (d₅₀ 8.70 µm) HA are beneficial to motivate the hydration process and improve the mechanical properties of castables, and could also effectively enhance the thermal shock resistance as it can homogeneously hydrate in the matrix and significantly promote the sintering process. Accompanied with the dehydration and phase transformation of HA, the high density of matrix structure can be found in the castables, which is responsible for an increase of mechanical performance. However, smaller particle size and higher specific surface area can also lead to severe hydration and excessive volume expansion of matrix cracks which could induce more microdamage during the hydration and dehydration.

For cost-effective production of dense silicon carbide (SiC) ceramic parts, pressureless sintering of SiC ceramics at lower temperatures is preferred. This study suggests a new additive composition based on Al₂O₃–Y₂O₃–MgO–CaO that leads to successful densification of SiC without applied pressure at a temperature as low as 1800°C. The effect of sintering temperature on the mechanical and thermal properties of SiC ceramics sintered with the new quaternary additive was investigated. Fracture toughness of the SiC ceramics continuously increased with increasing sintering temperature because of the growth of platelet SiC grains at temperatures ≥1750°C. In contrast, the flexural strength and hardness showed maxima at 1800°C due to the decreased density and increased grain size at higher sintering temperatures. The thermal conductivity of SiC ceramics increased with increasing sintering temperature from 1700 to 1900°C as a result of the decrease in lattice oxygen content in the SiC lattice. Typical sintered density, fracture toughness, hardness, flexural strength, and thermal conductivity of the 1800°C-sintered SiC ceramics were 98.8%, 5.2 MPa·m^1/2, 29.3 GPa, 347 MPa, and 83 Wm⁻¹ K⁻¹ at room temperature, respectively.

By adding 1.5 mol.% Bi(Mn_2/3Sb_1/3)O₃ (BMS), (Bi_1/2K_1/2)TiO₃ (BKT) ceramics show an excellent sintering ability in conventional oxide sintering process. In a wide temperature range from 1020–1050°C, the 0.985BKT–0.015BMS (BKMS) ceramics demonstrate a super-high relative density of 98% and low dielectric loss tan δ of 0.017. Even though the temperature reaches to 1060°C, BKMS ceramics maintain high relative density over 95% other than being collapsed as the pure BKT did. Besides, the BKMS ceramics sintered at 1020 to 1050°C present adequately high electrical properties. The enhanced sintering ability of BKMS ceramics is attributed to the increased viscosity of liquid induced by Sb⁵⁺ solving in the liquid phase during sintering. The work provides a way to realize the densification of BKT ceramics.

In this work, ternary CaTiO₃/reduced graphene oxide (rGO)/NiFe₂O₄ nanocomposite was successfully prepared using polyacrylamide gel route followed by hydrothermal method. It is observed that NiFe₂O₄ and CaTiO₃ nanoparticles are assembled on the surface of rGO. Furthermore, the formation of chemical bonding between the nanoparticles and rGO is confirmed. The photocatalytic activities of the samples were evaluated through the degradation of methylene blue and rhodamine B under the simulated sunlight irradiation. The results indicate that the ternary nanocomposite exhibits remarkable enhanced photocatalytic activity compared with bare CaTiO₃ and NiFe₂O₄. In this nanocomposite, the photogenerated electrons of CaTiO₃ and NiFe₂O₄ can be captured by rGO, leading to an increased separation and availability of electrons and holes for the photocatalytic reaction. Moreover, this nanocomposite exhibits obvious ferromagnetism and can be readily recovered by external magnetic field. The recycling photocatalytic experiment demonstrates that the nanocomposite possesses good photocatalytic reusability.

Bioglass has been widely applied in biological tissue engineering and other medical fields for many years. However, there are still many shortcomings in the application of bioglass, which needs further research. In this article, boron doped bioglasses were synthesized and characterized to evaluate the influence of the presence of B on degradation performance and biological activity. All sieved particles are irregular particles of micro-nano scale. After heat treatment at 600°C, the samples were amorphous, while microcrystals were produced in the sample heat treated at 800°C. X-ray diffraction and Fourier Transform Infrared Spectroscopy analyses indicate that the incorporation of boron changes the glass grid structure and promotes the formation of calcium silicate crystals in the case of heat treatment at 800°C. A dissolution study in simulated body fluid (SBF) was carried out, and ion release profiles and hydroxylapatite formation of the bioglasses were assessed. The test results show that the doping of B promotes the degradation of the samples, and the release of the Si in SBF influence the formation of the hydroxyapatite. And CaSiO₃ crystals in the samples heated at 800°C could release silicon quickly, which improve the bioactivity of bioglass-ceramics. In brief, the incorporation of B promotes the biodegradation and bioactivity of bioglass and bioglass-ceramics, and enhances bioglass performance, and thus, they are promising candidates for bone tissue engineering.

We have fabricated mesoporous silica-titania by a sol–gel method and evaluated the photocatalytic activity using acetaldehyde. The synthesized mesoporous silica-titania was effective for the removal of acetaldehyde from gas phase by adsorption and photodecomposition. In this study, the kinetic approach was carried out in order to clarify the adsorption-photodecomposition property of mesoporous silica-titania. The adsorption, direct photodecomposition and concerted adsorption-photodecomposition can be separately described in our simulation curves, which indicates that the adsorbability strongly affects the removal of acetaldehyde in the early stage and the photodecomposition after the strong adsorption of acetaldehyde on mesoporous silica-titania is important for the complete removal of acetaldehyde from gas phase.

Pr₂NiO₄ (PNO) powders were synthesized by the glycine-nitrite process (GNP) for use as the cathode in an intermediate-temperature (500–800°C) solid oxide fuel cell (IT-SOFC). When PNO powder was calcined at 1200°C for 1 h, the pure single phase with good crystallization K₂NiF₄-type structure was obtained. Moreover, samarium doped ceria (Ce_0.8Sm_0.2O_1.9, SDC) and NiO-SDC were used as electrolyte and anode, respectively. The maximal power density of 439 mW/cm² was obtained by the PNO/SDC/NiO-SDC cell at 800°C. Furthermore, the electrolyte surface of co-pressed SDC/NiO-SDC was modified with a chemical solution deposition derived SDC layer to improve the cell performance. Besides, the power density of the PNO/SDC layer/SDC/NiO-SDC cell increased to 487 mW/cm² at 800°C. These results suggest that PNO cathode materials prepared by GNP and chemical solution deposition modified SDC electrolyte have potential for application in anode-supported IT-SOFCs.

We succeeded in fabricating the uniform spherical titanium oxide (TiO₂) hollow particles improved photocatalytic activity by doping nitrogen under visible light irradiation using new processing. To prepare the uniform spherical nitrogen-doped TiO₂ particles with monodispersed size distribution and monodispersed pore distribution, we performed the reaction crystallization within the confined droplet by inkjet nozzle. The absorption edge of the TiO₂ particles shifted to the lower wavelength side with an increase in the sintering temperature. TiO₂ particles prepared by an inkjet process exhibited spherical porous structures with uniform size distribution, resulting that this process would be controllable to nitrogen-doped TiO₂ particles. The results indicated that the chemical states of the nitrogen doping and the light absorption characteristics of the TiO₂ particles could be controlled by the sintering temperature.

Hydroxyapatite (HAp) exhibits superior biocompatibility, ion-exchange ability and high adsorption property has attracted much attention as one of the most well-known ceramic functional materials. We have previously reported the efficient oxidative decomposition of volatile organic compounds (VOC) on commercial HAp powders, which makes HAp a promising alternative material of precious metal nanoparticle catalyst for environmental purification. In this work, HAp with oriented crystal growth of a-plane and c-plane were synthesized via air-liquid interface precipitation in solution, and the influence of crystal orientation on VOC decomposition performance was systemically investigated. As a result, HAp with preferential growth of c-plane performs higher catalytic VOC decomposition activity, which can be attributed to the large number of active radicals generated on surface despites the relative smaller sufficient surface area. The results in this study highlight the important relation between crystal structure of HAp and the decomposition activity of VOC, which also provide useful information for the structure design of ceramic functional materials.

Porous ceramic filters made of MgAl₂O₄ spinel are promising due to their excellent thermal and chemical stability. In this study, toward future cross-flow ultrafiltration applications, reactive synthesis of porous MgAl₂O₄ membranes on a macroporous Al₂O₃-based ceramic tube has been examined. Fine (0.2 µm) and coarse (0.7 µm) α-Al₂O₃ powders and two types of MgO sources, i.e., MgO (∼2.8 µm) and MgCO₃ (basic) [hydromagnesite Mg₅(CO₃)₄(OH)₂·4H₂O] (∼5.5 µm) powders were used as starting materials for the reactive synthesis of porous MgAl₂O₄ membranes. For the intermediate layer, MgCO₃ (basic) powder was favorable as a MgO source because it can clog up the large (15 µm) pores in the Al₂O₃-based tube. Meanwhile, for the top layer, MgO powder with finer particle size was favored to obtain homogeneous layer for ultrafiltration.