• Korean Journal of Materials Research
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• v.22 no.2
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• pp.103-109
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• 2012

Red-emitting $Eu^{3+}$-activated $(Y_{0.95-x}Al_x)VO_4$ (0 < x $\leq$ 0.12) nanophosphors with the particle size of ~30 nm and the high crystallinity have been successfully synthesized by a hydrothermal reaction. In the synthetic process, deionized water as a solvent and ethylene glycol as a capping agent were used. The crystalline phase, particle morphology, and the photoluminescence properties of the excitation spectrum, emission intensity, color coordinates and decay time, of the prepared $(Y_{0.95-x}Al_x)VO_4:Eu^{3+}$ nanophosphors were compared with those of the $YVO_4:Eu^{3+}$. Under 147 nm excitation, $(Y_{0.95-x}Al_x)VO_4$ nanophosphors showed strong red luminescence due to the $^5D_0-^7F_2$ transition of $Eu^{3+}$ at 619 nm. The luminescence intensity of $YVO_4:Eu^{3+}$ enhanced with partial substitution of $Al^{3+}$ for $Y^{3+}$ and the maximum emission intensity was accomplished at the $Al^{3+}$ content of 10 mol%. By the addition of $Al^{3+}$, decay time of the $(Y,Al)VO_4:Eu^{3+}$ nanophosphor was decreased in comparison with that of the $YVO_4:Eu^{3+}$ nanophosphor. Also, the substitution of $Al^{3+}$ for $Y^{3+}$ invited the improvement of color coordinates due to the increase of R/O ratio in emission intensity. For the formation of transparent layer, the red nanophosphors were fabricated to the paste with ethyl celluloses, anhydrous terpineol, ethanol and deionized water. By screen printing method, a transparent red phosphor layer was formed onto a glass substrate from the paste. The transparent red phosphor layer exhibited the red emission at 619 nm under 147 nm excitation and the transmittance of ~80% at 600 nm.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.189-194
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• 2014

In this study, from a new x-ray detector that combines a columnar CsI:Na scintillation layer with a photosensitive mercuric iodide layer was investigated. In this structure, X-rays are converted into visible light on a thick CsI:Na layer, which is then converted to electric charges in a thin $HgI_2$ bottom layer. The thin coplanar mercuric iodide films as a photosensitive converter requiring only a few tens of volts of bias, associated with a thick columnar coating of phosphor layer, were simulated and designed. The results of this research suggest that the new coplanar x-ray detector with a hybrid-type structure can resolve the following problems: high voltage from the a-Se, and low conversion efficiency from the indirect conversion method. The results of this research suggest that the new CsI:Na/$HgI_2$ x-ray detector with a double-layer type structure can resolve the following problems: high voltage from the direct conversion method, and low conversion efficiency from the indirect conversion method.

• Radiation Oncology Journal
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• v.21 no.1
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• pp.54-65
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• 2003

Purpose : To analyze the gene expression Profiles of uterine ceulcal cancer, and its variation after radiation therapy, with or without concurrent chemotherapy, using a CDNA microarray. Materials and Methods :Sixteen patients, 8 with squamous ceil carcinomas of the uterine cervix, who were treated with radiation alone, and the other 8 treated w14h concurrent chemo-radiation, were Included in the study. Before the starling of the treatment, tumor biopsies were carried out, and the second time biopsies were peformed after a radiation dose of 16.2$\~$27 Gy. Three normal cervix tissues were used as a control group. The microarray experiments were peformed with 5 groups of the total RNAs extracted individually and then admixed as control, pre-radiation therapy alone, during-radiation therapy alone, pre-chemoradiation therapy, and during-chemoradlation therapy. The 33P-iabeled CDNAS were synthesized from the total RNAs of each group, by reverse transcription, and then they were hybridized to the CDNA microarray membrane. The gene expression of each microarrays was captured by the intensity of each spot produced by the radioactive isotopes. The pixels per spot were counted with an Arrayguage, and were exported to Microsoft Excel The data were normalized by the Z transformation, and the comparisons were peformed on the Z-ratio values calculated. Results : The expressions of 15 genes, including integrin linked kinase (ILK), CDC28 protein kinase 2, Spry 2, and ERK 3, were increased with the Z-ratio values of over 2.0 for the cervix cancer tissues compared to those for the normal controls. Those genes were involved In cell growth and proliferation, cell cycle control, or signal transduction. The expressions of the other 6 genes, Including G protein coupled receptor kinase 5, were decreased with the Z-ratio values of below -2.0. After the radiation thorapy, most of the genes, with a previously Increase expressions, represented the decreased expression profiles, and the genes, with the Z-ratio values of over 2.0, were cyclic nucleotlde gated channel and 3 Expressed sequence tags (EST). In the concurrent chemo-radiation group, the genes involved in cell growth and proliferation, cell cycle control, and signal transduction were shown to have increased expressions compared to the radiation therapy alone group. The expressions of genes involved in anglogenesis (angiopoietln-2), immune reactions (formyl peptide receptor-iike 1), and DNA repair (CAMP phosphodiesterase) were increased, however, the expression of gene involved In apoptosls (death associated protein kinase) was decreased. Conclusion : The different kinds of genes involved in the development and progression of cervical cancer were identified with the CDNA microarray, and the proposed theory is that the proliferation signal stalls with ILK, and is amplified with Spry 2 and MAPK signaling, and the cellular mitoses are Increased with the increased expression oi Cdc 2 and cell division kinases. After the radiation therapy, the expression profiles demonstrated 4he evidence of the decreased cancer cell proliferation. There was no sigificant difference in the morphological findings of cell death between the radiation therapy aione and the chemo-radiation groups In the second time biopsy specimen, however, the gene expression profiles were markedly different, and the mechanism at the molecular level needs further study.