Advanced
fabrication methods must be developed for magnetic–polymeric
particles, which are used in medical diagnostics, drug delivery, separation,
and environmental remediation. The development of scalable fabrication
processes that enables simultaneously tuning of diameters and compositions
of magnetic–polymeric particles remains a major challenge.
Here, we proposed the production of high-quality magnetic-composite
particles through a universal method based on the in-fiber Plateau–Rayleigh
instability of polymeric fibers. This method can simultaneously control
the particle diameter, hybrid configuration, and functional properties.
The diameter of magnetic–polymeric particles can be reproducibly
tuned from ∼20 nm to 1.25 mm, a wide range unachievable by
conventional solution methods. The final diameter was controlled by
the inner/outer fiber diameter ratio. We further showed that the prepared
magnetic–polymeric composite particles can be used for the
highly efficient recovery of heavy metals (98.2% for Cd2+) and for the precise separation of immune cells (CD4+ T cells). Overall, the in-fiber manufacture method can become a
universal technology for the scalable preparation of different types
of magnetic–polymeric composite particles with diverse functionalities.
The
applications of scintillating fiber in high-resolution medical
imaging, remote radiation monitoring, and microbeam radiation therapy
have raised a growing demand of bismuth–germanate (BGO) glass
fiber. However, the task of construction of colorless BGO glass fiber
has been met with limited success. Here, we present a renewable process
that can help to achieve BGO scintillating fiber, based on glass relaxation
and crystallization mediated dissolution of unexpected Bi center.
The experimental results indicate that the strategy can improve the
optical transmittance up to more than 73.17% at 483 nm, which is ∼6.28
times higher than that of the conventional material. Importantly,
the obtained nanostructured BGO exhibits bright visible luminescence
under excitation with X-ray. Furthermore, it can host various types
of rare-earth dopants, and the radiation-induced luminescence can
be tuned in a wide waveband region from visible to infrared waveband.
In addition, colorless BGO fiber with bright emission is also successfully
constructed, and the radiation probing test demonstrates the achievement
of ∼19.48 times improvement in the detection sensitivity. Our
results highlight the approach based on the dynamic glass relaxation
may provide new opportunities for construction of scintillating glass
fiber and compact radiation fiber detector.
Chemical stoichiometric Ge-As-S glasses were prepared, and their thermal properties, refractive index (n), optical bandgap, Raman gain, and femtosecond laser damage were examined. Results revealed that the n and density (ρ) of the glasses decreased as Ge concentration increased, whereas the bandgap and glass transition temperature (Tg) increased. The Raman gain coefficients (gR) of the samples were calculated on the basis of spontaneous Raman scattering spectra. gR decreased from 2.79 × 10-11 m/W for As2S3 to 1.06 × 10-11 m/W for GeS2 as Ge concentration increased. However, the smallest gR was 100 times higher than that of fused silica (0.89 × 10-13 m/W). When these glasses were irradiated by a laser with a pulse width of 150 fs and a power of 33 mW at 3 μm, the damaged area and depth decreased and the damage threshold increased gradually as Ge concentration increased. Raman spectra and composition analysis indicated that surface oxidation probably occurred and sulfur gasified at a high laser power. Although the gR decreased as Ge was added, the laser damage threshold of Ge-As-S glasses was higher than that of the As2S3 glass. Thus, these glasses are potential materials for Raman gain media.
The construction of cerium-doped materials is of great technological importance for various applications, including smart lighting, biological shielding and high-energy ray and particle detection. A major challenge is the efficient prevention of the undesired colorization after cerium doping. Here we present the nanocrystallization method for constructing colorless cerium-doped glass with extremely high cerium concentration (15 mol%). The structure and optical characterizations confirm that the notable color change of glass is associated with the precipitation of CeF crystalline phase during heat-treatment. The chemical state investigation shows that most of cerium ions exist in the form of Ce in both the glass and glass-ceramic samples. The chemical environment study indicates a dramatic change in the local structure unit from -Ce-O- to -Ce-F-, which is believed to dominate the decoloring phenomenon in cerium doped glass. As a result, a significant improvement in the ultraviolet excited luminescence (~35 times enhancement in intensity) and scintillating performance can be achieved, pointing to potential applications in X-ray detection.
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