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In recent years, near‐infrared quantum dots (NIR QDs) have emerged as a promising candidate for biological imaging owing to their strong fluorescence penetrating into biological tissues and high imaging signal‐to‐noise ratio. Among various materials, InP QDs are environmentally friendly and have a relatively narrow bandgap of 1.35 eV, which provides a possibility for their emission wavelength to extend to the near‐infrared region. However, the strong reactivity of the precursor of phosphorus makes it challenging to synthesize NIR InP QDs, as it leads to rapid nucleation of the InP core. Herein, a method of epitaxial growth is reported to synthesize NIR InP QDs. Through high‐temperature nucleation and low‐temperature epitaxial growth, NIR InP QDs larger than 15 nm in size and with an emission wavelength of 807 nm are successfully synthesized. Furthermore, by removing InPOx defects on the surface of the core through HF etching, the quantum yield (QY) is increased from 6% to 12%. Ligand exchange successfully converted oil‐soluble ligands into water‐soluble ones, leading to excellent performance in cell imaging. The study provides a promising approach to the synthesis of desirable NIR InP QDs for use in biomedical imaging applications. [ABSTRACT FROM AUTHOR]

In this study, ZnO‐B2O3‐SiO2 (ZBS) glass was employed as a sintering facilitator, enabling low‐temperature sintering of SmTaO4 and YTaO4 ceramics. The influence of varying quantities of ZBS glass on sintering behavior and phase composition was investigated to reveal the low‐temperature sintering mechanism. ZBS glass exhibits favorable wetting behavior on the SmTaO4 and YTaO4 ceramic matrices and dramatically decreases the initial shrinkage temperature of ceramics throughout the sintering process. Composited with 20 wt. % ZBS and sintered at their optimal sintering temperature, the composite ceramics of SmTaO4 and YTaO4 possess favorable microwave dielectric properties: εr = 8.46, Q×f = 15,723 GHz, and τf = –6.68 ppm/°C (at 14.339 GHz), and εr = 4.21, Q×f = 18,939 GHz, and τf = –18.92 ppm/°C (at 15.512 GHz), respectively. [ABSTRACT FROM AUTHOR]

A glass frit containing Li2O–MgO–ZnO–B2O3–SiO2 component was used to explore the low-temperature sintering behaviors and microwave dielectric characteristics of tri-rutile MgTa2O6 ceramics in this study. The good low-firing effects are presented due to the high matching relevance between Li2O–MgO–ZnO–B2O3–SiO2 glass and MgTa2O6 ceramics. The pure tri-rutile MgTa2O6 structure remains unchanged, and high sintering compactness can also be achieved at 1150°C. We found that the Li2O–MgO–ZnO–B2O3–SiO2 glass not only greatly improves the low-temperature sintering characteristics of MgTa2O6 ceramics but also maintains a high (quality factor (Q) × resonance frequency (f)) value while still improving the temperature stability. Typically, great microwave dielectric characteristics when added with 2wt% Li2O–MgO–ZnO–B2O3–SiO2 glass can be achieved at 1150°C: dielectric constant, εr = 26.1; Q × f = 34267 GHz; temperature coefficient of resonance frequency, τf = −8.7 × 10−6 /°C. [ABSTRACT FROM AUTHOR]

Designing and fabricating antennas that exhibit low losses and are compact, lightweight, and highly radiation efficient are challenging in the wireless‐communication field. In this study, we simulated and fabricated microstrip patch antennas using β‐CaSiO3 low‐temperature co‐fired ceramic (LTCC) as dielectric resonator substrate. Compact ceramics that show good microwave dielectric properties (a relative dielectric constant [εr] of 6.57, high‐quality factor [Q × f] of 35 086 GHz [@14.85 GHz], and temperature coefficient of frequency [τf] of −33.56 ppm °C−1 for the optimal composition) were obtained when Li2O–CaO–B2O3–CuO glass was added to β‐CaSiO3 and sintered at 950°C. The high‐frequency properties of these composite ceramics reveal that the dielectric constant and dielectric loss are stable in the 38−58 and 70−90 GHz ranges, respectively. Furthermore, a circularly polarized antenna fabricated using a CaSiO3‐based ceramic shows a high radiation efficiency (92.04%) and gain (3.35 dBi) at a center frequency of 2.5 GHz. These β‐CaSiO3 composite ceramics offer promising prospects for high‐frequency use as well as in mobile communication applications. This study provides insight for the development of innovative antennas with new LTCC materials. [ABSTRACT FROM AUTHOR]

In the present work, the influence of different types of ionic substitutions at Zn and Ti sites on the rutile Zn0.15Nb0.3Ti0.55O2 ceramics were discussed through Rietveld refinement and complex chemical bond theory. The results indicate that different types of ions can be appropriately doped to form the rutile solid solutions. The doping of small radius ions at the Zn site leads to a reduction in crystal cell volume, and the downward trend of dielectric constant is consistent with bond ionicity; Doping large radius ions at Ti sites leads to an increase in crystal cell volume, and a more pronounced decrease in dielectric constant, which is also consistent with the trend of covalency. The trend of the Q × f value of rutile ceramics doped at different sites is consistent with the trend of the the total lattice energy. [ABSTRACT FROM AUTHOR]