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The influence of cooling history for the Zn3Ga2Ge2O10/Cr3+ phosphors prepared by solid state reaction on the spectral properties was discovered, and an anticounterfeiting scheme based on the identification with smartphone was proposed and experimentally demonstrated using the studied phosphors. A combination of color-tunable visible fluorescence emission and near-infrared (NIR) afterglow emission in Zn3Ga2Ge2O10/x mol % Cr3+(x = 0, 0.05, 1, 2, 3, and 4) phosphors to achieve multimode anticounterfeiting was reported. It is found that with the increasing Cr3+ concentrations, the visible emission can be tuned from green, light pink, and light red to deep red under 254 nm ultraviolet (UV) excitation. This phenomenon is related to the formation of oxygen vacancies in the host during the process of natural cooling and the characteristic emission of Cr3+. In addition, the persistent time of the Cr3+ emission centered at 700 nm can be also tuned by various Cr3+ concentrations. A possible mechanism was deduced to explain the afterglow phenomenon. Lastly, a flower pattern applied in anticounterfeiting was fabricated using the Zn3Ga2Ge2O10/x mol % Cr3+ (x = 0, 0.05, 1, 2, 3, and 4) phosphors to present tunable color and NIR afterglow signals at different excitation modes, and the camera of smartphone was chosen as a detection tool to take the NIR images. The results obtained above suggest that the prepared phosphors at natural cooling condition have great potential in affording advanced optical anticounterfeiting.
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The optical transition properties of trivalent rare earth (RE3+) doped luminescent materials have received extensive attention. The Judd-Ofelt theory is an effective tool for exploring the optical transition properties for the 4f-4f transitions of lanthanides. The aim of this work is to discover the effect of Er3+ concentration and different Ln3+ ions on the Judd-Ofelt parameters in LnOCl:Er3+ (Ln = Y, La, Gd) phosphors. Oxychloride LnOCl:Er3+ (Ln = Y, La, Gd) phosphors were produced via a single displacement reaction technique. The Judd-Ofelt calculation procedure for RE3+ doped powders was modified and then adopted to obtain the Judd-Ofelt parameters of Er3+ in the studied phosphors. Meanwhile, a new route for examining the Judd-Ofelt calculation quality was proposed and used. It was found that the Er3+ doping concentration slightly affects the optical transition properties of Er3+ in YOCl and LaOCl, but greatly affects the optical transition properties in GdOCl. Moreover, it was also found that the optical transition properties of Er3+ depend also on Ln3+ (Ln = Y, La, Gd) though the crystal structure of these compounds is similar. The Judd-Ofelt parameters of Er3+ are the smallest in LaOCl:Er3+, medium in YOCl:Er3+, but the biggest in GdOCl:Er3+ when the doping concentration is the same.
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PURPOSE: The purpose of this study is to provide a new method to locate the foramen rotundum (FR) based on the structures in the wall of sphenoid. MATERIALS AND METHODS: Computed tomographic angiography images of 172 FR in adults and 10 bony specimens were reviewed. The measurement was on coronal, sagittal, and axial planes after multiplanar reconstruction. The diameter, length, and direction of FR were measured. The middle lowest point of sellar region, the sagittal midline, and the bottom of sphenoid sinus were selected as the landmarks to locate the FR. RESULT: The FR can be found and identified easily on computed tomographic angiography image. The bony diameter measured in CT image is in accordance with that in specimen. The anterior opening and posterior opening can be located by the stationary structures in the sphenoid sinus. CONCLUSIONS: The FR is a stationary bony structure; its length, diameter, and angle are relatively constant; and it can be easily located by the data measured in this study. The FR should be protected in the process of transsphenoid approach as well as be precisely located by the procedure about it.
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Processamento de Imagem Assistida por Computador/métodos , Fossa Pterigopalatina/diagnóstico por imagem , Osso Esfenoide/diagnóstico por imagem , Seio Esfenoidal/diagnóstico por imagem , Adolescente , Adulto , Idoso , Angiografia/métodos , Endoscopia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Órbita/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Nervo Trigêmeo/diagnóstico por imagem , Adulto JovemRESUMO
PURPOSE: The aim of this study is to locate pterygopalatine fossa (PPF) and the opening of its communicating canals by accessing the relationship between PFF and the endoscopic landmarks such as the tubercular recess (TR) and middle lowest point of sellar floor (SF) as well as analyze the relation between PPF and important structures such as internal carotid artery (ICA) and optic canal (OC). MATERIALS AND METHODS: Computer topographic angiography (CTA) images of 118 PPF regions were reviewed. The measurement was on coronal, sagittal, and axial planes after multiplanar reconstruction (MPR). The location of PPF and its relationship to the sphenoid sinus, ICA, and OC were studied. The communicating canals of PPF, which were related to the transsphenoid approach, were three-dimensionally measured by the stationary structures, such as the middle lowest point of SF, the sagittal midline, and the top and bottom wall of sphenoid sinus. RESULT: The posterior part of PPF was located by the middle lowest point of SF. The anterior opening of sphenopalatine foramen (SPF), pterygoid canal (PC), palatovaginal canal (PVC), and foramina rotundum (FR) have relative stationary position, which can be located by the landmarks of sellar region during the endoscopic surgery. CONCLUSIONS: Pterygopalatine fossa is related to numerous neurovascular structures. Accurate understanding of the radiologic anatomy of PPF is beneficial for the PPF disease diagnosis, the selection of treatment plan and the prognosis evaluation.
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Fossa Pterigopalatina/diagnóstico por imagem , Sela Túrcica/diagnóstico por imagem , Adolescente , Adulto , Idoso , Pontos de Referência Anatômicos/diagnóstico por imagem , Angiografia/métodos , Artéria Carótida Interna/diagnóstico por imagem , Endoscopia/métodos , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Masculino , Pessoa de Meia-Idade , Órbita/diagnóstico por imagem , Palato Duro/diagnóstico por imagem , Osso Esfenoide/diagnóstico por imagem , Seio Esfenoidal/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Adulto JovemRESUMO
PURPOSE: This study aims to provide an anatomic data of posterior communicating artery (PComA) and its anatomic relationship to the adjacent structures, so as to guide surgeons in the surgery of internal carotid artery-posterior communicating artery aneurysm clipping and sellar tumors resection without injuring the PComA. METHODS: Computer topographic angiography images of 123 individuals were reviewed, and the measurements were done on coronal, sagittal, axial, and other user-defined planes after multiplanar reconstruction. Posterior communicating artery was classified in the reconstructed three-dimensional image, measured in proper planes, and located by the structures such as anterior clinoid process (ACP), posterior clinoid process (PCP), and sagittal midline. RESULTS: Six types of PComA were identified in this study based on its existence and origin. The initial part of PComA can be located by ACP, PCP, and sagittal midline based on some particular angles and distances. CONCLUSIONS: Posterior communicating artery varies in different individuals, and the radiologic study of it is an optimal way to analyze the variances. The anatomic relations between PComA and basic skull structures such as the ACP and PCP are especially important for neurosurgeons.
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Artéria Carótida Interna/diagnóstico por imagem , Artéria Carótida Interna/cirurgia , Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/cirurgia , Neoplasias Hipofisárias/diagnóstico por imagem , Neoplasias Hipofisárias/cirurgia , Sela Túrcica/diagnóstico por imagem , Sela Túrcica/cirurgia , Tomografia Computadorizada Espiral/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Angiografia Cerebral/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Y2O3:Eu3+ nanocrystals were prepared by ultrasonic chemistry and characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The resulting nanocrystals were found to be nanoparticles with size distribution in the range of 50-80 nm. The phase of all the samples was cubic. The luminescence properties of the samples were systematically studied and show significant change with concentration of surfactant and annealing temperature. The results show that the intensity of the excitation and emission spectra of Y2O3:Eu3+ nanocrytals increases gradually with increasing P123 concentration and annealing temperature. The fluorescence lifetime of 5D0 level Eu3+ decreases with increasing P123 concentration and increases with annealing temperature. The photoluminescence stability of Y2O3:Eu3+ nanocrytals becomes worse with increasing P123 concentration and annealing temperature.
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The terbium complex Tb(acac)2AA (acac: acetyl acetone, AA: acrylic acid) was incorporated into polystyrene (PS) matrix and electrospun into various composite fibers. The mass ratios of rare-earth complex to polymer were fixed in all composite fibers. The diameters of the composite fibers decrease with increase in the collection distance during electrospinning. The luminescence properties of the Tb(acac)2AA/PS composite fibers were studied in comparison to those of the pure Tb complex. The excitation bands became narrower and blue-shifted compared with that of the pure complex in all of the Tb(acac)2AA/PS composite fibers. The fluorescence lifetime of the 5D4 state of Tb3+ ion in the composite fibers was shorter than that of the Tb complex. The effect of the fiber diameter on the luminescence properties was also studied. As a result, the fluorescence lifetimes of the 5D4 state in all of the Tb(acac)2AA/PS composite fibers decreased gradually with decrease in diameter.
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The development of white phosphors that can be activated in near-ultraviolet light is highly important in the field of LED lighting. In this work, a series of color-tunable Y2(Ti1-xHfx)2O7:Eu phosphors were prepared by adjusting the HfO2 and Eu3+ concentrations. In particular, white Y2(Ti0.8Hf0.2)2O7:Eu phosphors were successfully synthesized and emitted a broad band covering the entire visible light region upon excitation with 340 nm UV light. The white banded materials were composed of Eu2+ and Eu3+ emissions and HfO2 defect emission. The formation of Eu2+ ions was caused by the introduction of HfO2, which causes self-reduction of Eu3+ ions but does not require additional reducing agents. The white Y2(Ti0.8Hf0.2)2O7:Eu phosphors exhibit low color shifting at high temperature, which is very important for LED applications. The chromaticity shift of the Y2(Ti0.8Hf0.2)2O7:0.2Eu phosphor is 2.83 × 10-2 at 503 K, which is only 54.8 % that of commercial three-color white phosphors at the same temperature. The Ra value did not decrease significantly with increasing temperature and reached 90.2 at 383 K. Y2 (Ti0.8Hf0.2)2O7:0.2Eu phosphors were assembled with a 365 nm LED chip to fabricate a WLED device that showed excellent white-colored coordinates (0.345, 0.358) and a high Ra value of 90.1 under a 300 mA current.
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Anti-counterfeiting labels based on luminescence materials are a newly emerging technique for protecting legal goods and intellectual property. In the anti-counterfeiting field to prevent forgery and cloning, luminescence materials with properties different from the commercialized and traditional ones are in urgent need. In this work, multicolor-emitting Er3+ single-doped and Er3+/Yb3+ co-doped Zn2GeO4 phosphors combining static and dynamic identifications were developed in order to achieve advanced anti-counterfeiting application. The variation of trap content with increasing the doping content of rare earth ions was analyzed through X - ray photoelectron spectroscopy, thermoluminescence analysis. It was found that there are two types of traps with different depth in Zn2GeO4 phosphors. The depths of the traps were experimentally confirmed to be 0.68 and 0.79 eV, respectively. The transient photocurrent response measurement confirmed the existence of charge carriers, and the mechanism for long persistent luminescence was deduced. The multicolor upconversion mechanisms under 980 and 1550 nm excitation were also discovered. Based on the multicolor steady and transient emission features, an anti-counterfeiting pattern was designed using the phosphors. Static and dynamic identification was demonstrated and presented in detail. Finally, it is indicated that the studied phosphors are excellent candidates for potential applications in luminescence anti-counterfeiting labels.
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Raising photoelectric conversion efficiency and enhancing heat management are two critical concerns for silicon-based solar cells. In this work, efficient Yb3+ infrared emissions from both quantum cutting and upconversion were demonstrated by adjusting Er3+ and Yb3+ concentrations, and thermo-manage-applicable temperature sensing based on the luminescence intensity ratio of two super-low thermal quenching levels was discovered in an Er3+/Yb3+ co-doped tungstate system. The quantum cutting mechanism was clearly decrypted as a two-step energy transfer process from Er3+ to Yb3+. The two-step energy transfer efficiencies, the radiative and nonradiative transition rates of all interested 4 f levels of Er3+ in NaY(WO4)2 were confirmed in the framework of Föster-Dexter theory, Judd-Ofelt theory, and energy gap law, and based on these obtained efficiencies and rates the quantum cutting efficiency was furthermore determined to be as high as 173% in NaY(WO4)2: 5 mol% Er3+/50 mol% Yb3+ sample. Strong and nearly pure infrared upconversion emission of Yb3+ under 1550 nm excitation was achieved in Er3+/Yb3+ co-doped NaY(WO4)2 by adjusting Yb3+ doping concentrations. The Yb3+ induced infrared upconversion emission enhancement was attributed to the efficient energy transfer 4I11/2 (Er3+) + 2F7/2 (Yb3+) â 4I15/2 (Er3+) + 2F5/2 (Yb3+) and large nonradiative relaxation rate of 4I9/2. Analysis on the temperature sensing indicated that the NaY(WO4)2:Er3+/Yb3+ serves well the solar cells as thermos-managing material. Moreover, it was confirmed that the fluorescence thermal quenching of 2H11/2/4S3/2 was caused by the nonradiative relaxation of 4S3/2. All the obtained results suggest that NaY(WO4)2:Er3+/Yb3+ is an excellent material for silicon-based solar cells to improve photoelectric conversion efficiency and thermal management.
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A series of Tb3+-doped Sr2YTaO6 double perovskite phosphors (SYT:Tb3+) were synthesized using a conventional solid-state reaction method. A strong green emission was observed in the SYT:Tb3+ phosphors, and the optimal doping concentration of Tb3+ was confirmed to be 5 mol%. The electric dipole-dipole interaction was ascribed to be the main mechanism for the luminescence concentration quenching. Analysis of the concentration-dependent fluorescence decay confirmed that the self-generated quenching model holds for the dynamic process of Tb3+ decays in SYT. Furthermore, the internal quantum efficiencies, non-radiative transition rates, and energy transfer rates of the 5D4 level for the SYT:Tb3+ samples were estimated, respectively. The luminescence thermal stability of the sample was also evaluated based on the Arrhenius model. The chromaticity shift of the SYT:5 mol% Tb3+ phosphor was examined to be 0.013 when the sample temperature was increased from 303 to 483 K, thus indicating excellent chromaticity shifting resistance under high temperature conditions. Moreover, the Judd-Ofelt parameters were calculated from the emission spectra of SYT:Tb3+ to be Ω2 = 0.29 × 10-20, Ω4 = 0.45 × 10-20, and Ω6 = 0.72 × 10-20 cm2, respectively. The fluorescence branching ratios and radiative transition rates for the 5D4 level were calculated based on the obtained Judd-Ofelt parameters. Finally, a white light-emitting diode (LED) prototype was assembled using a 310 nm LED chip combined with a prepared green SYT:Tb3+ phosphor and two other commercial blue and red phosphors. The obtained warm white light exhibits good chromaticity coordinates (0.32, 0.32) and a high color rendering index of 96.1. Based on the above results, it can be known that the prepared SYT:Tb3+ phosphors have a potential application as green emitting phosphors in white LEDs.
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MicroRNA is strongly associated with tumor growth and development. This study examined the potential roles of miR-125b in glioma growth. We found that miR-125b promotes glioma cell line growth and clone formation, and protects the glioma cells from apoptosis in vitro. The miR-125b-transfected glioma cells also demonstrated increased growth after in vivo transplantation. We further identified that miR-125b inhibits Connexin43 expression, and the overexpression of Connexin43 antagonizes the effects of miR-125b in cell growth and anti-apoptosis. We conclude that miR-125b regulates glioma growth partly through Connexin43 protein.
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Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Conexina 43/antagonistas & inibidores , Glioma/genética , Glioma/patologia , MicroRNAs/metabolismo , Regiões 3' não Traduzidas/genética , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Sequência de Bases , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Células Clonais , Conexina 43/genética , Conexina 43/metabolismo , Dacarbazina/análogos & derivados , Dacarbazina/farmacologia , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HEK293 , Humanos , Camundongos , Camundongos Nus , MicroRNAs/genética , Dados de Sequência Molecular , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , TemozolomidaRESUMO
Patients suffer hemispatial neglect after stroke. However, whether the function of spatial attention is reorganized to the contralateral brain remains poorly understood. Here we present a case report of neonatal stroke to demonstrate the reorganization of spatial attention in the contralateral hemisphere using a series of tests including star cancellation task, line bisection test, the bells test, letter cancellation test, and drawing tests. The patient underwent right hemispherectomy for treatment of refractory epilepsy and did not have hemispatial neglect after surgery, supporting transfer of function prior to the operation. After analyzing the literature in this field, we proposed that the function of spatial attention may transfer to the contralateral side in childhood. Thus, this study sheds new light on the preserved function of spatial attention in neonatal stroke patients even when hemispherectomy is performed.
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Atenção/fisiologia , Lateralidade Funcional/fisiologia , Transtornos da Percepção/etiologia , Acidente Vascular Cerebral/fisiopatologia , Hemisferectomia/métodos , Humanos , Lactente , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Transtornos da Percepção/diagnóstico , Acidente Vascular Cerebral/cirurgia , Tomografia Computadorizada por Raios XRESUMO
OBJECTIVE: To analyze the microsurgical treatment regimens of cavernous sinus hemangioma. METHODS: The microsurgical experiences were reviewed and analyzed for 17 cases of operatively and pathologically confirmed cavernous sinus cavernous hemangioma at our hospital from January 2008 to January 2012. There were 6 males and 11 females with an average age of 48.5 years. RESULTS: Among them, there were total (n = 14) and subtotal (n = 3) resection. And there was no occurrence of postoperative mortality. According to the results of imaging follow-up, total resection cases had no recurrence while subtotal residual tumor was progression-free after radiotherapy. Oculomotor, abducens and trigeminal nerves retained varying degrees of neurological function at 3-6 months postoperation. CONCLUSION: Based on the size of tumor and growth direction, appropriate surgical approaches may be selected. And a combination of skilled microsurgical techniques and proper resection may reduce bleeding and facilitate total tumor removal so as to reduce the degree of neurological deficits and improve the long-term postoperative quality-of-life.
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Seio Cavernoso , Hemangioma Cavernoso/cirurgia , Microcirurgia , Adulto , Idoso , Seio Cavernoso/patologia , Seio Cavernoso/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do TratamentoRESUMO
We have created a new method of ZnS nanospheres synthesis. By interface-mediated precipitation method (IMPM), monodisperse ZnS nanoparticles was synthesized on the particle surface of sulfate-reducing bacterium nutritious agar culture. Sulfate-reducing bacterium (SRB) was used as a sulfide producer because of its dissimilatory sulfate reduction capability, meanwhile produced a variety of amino acids acting as templates for nanomaterials synthesis. Then zinc acetate was dispersed into nutritious agar plate. Subsequently agar plate was broken into particles bearing much external surface, which successfully mediated the synthesis of monodisperse ZnS nanoparticles. The morphology of monodisperse ZnS nanospheres and SRB were examined by scanning electron microscopy (SEM), and the microstructure was investigated by X-ray diffraction (XRD). The thermostability of ZnS nanoparticles was determined by thermo gravimetric-differential thermo gravimetric (TG-DTG). The maximum absorption wavelengh was analysed with an ultraviolet-visible spectrophotometer within a range of 199-700 nm. As a result, monodisperse ZnS nanoparticles were successfully synthesized, with an average diameter of 80 nm. Maximum absorption wavelengh was 228 nm, and heat decomposed temperature of monodisperse ZnS nanoparticles was 596°C.
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Bactérias/metabolismo , Nanopartículas/química , Sulfatos/metabolismo , Sulfetos/química , Compostos de Zinco/química , Bactérias/ultraestrutura , Cristalografia por Raios X , Nanopartículas/ultraestrutura , Fenômenos Ópticos , Oxirredução , Espectrofotometria Ultravioleta , Temperatura , TermogravimetriaRESUMO
Fluorescent CDs tend to undergo solid-state aggregation quenching in powder form. This is caused by the stacking of π-π conjugate structures and excessive resonant energy transfer. Moreover, various forms of N play an important role in white CDs suitable for LED applications. White, single-component, non-N-doped CDs have never been reported for LED application. In this study, to overcome this limitation, we developed Ga-doped CD powders containing no N element that exhibit ultra-wideband white emission in the range of 420-800 nm for LED applications and were able to resist solid-state aggregation quenching. Furthermore, the Ga-doped CD powders demonstrated excellent luminescence stability under high temperatures. Another strength of the Ga-doped CD powders is their large Stokes shift, where the peak center of white emission shifts from 550 nm to 650 nm under 365 nm excitation as the Ga doping concentration is adjusted from 0.05 to 0.6 (Ga : H2O, mass ratio). The full width at half-maximum can reach 262 nm. Additionally, the Ga-doped CD powders exhibit good luminescence stability under long-time exposure to an air atmosphere. Their luminescent intensity retained 70%-74% of the initial values even after being left in natural placement for 100 days. Moreover, the Ga-doped CDs demonstrate afterglow features.
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M-NC catalysts were prepared by a combination of the electrospinning method and thermal treatment. For the first time, the contribution of N-species to the ORR (oxygen reduction reaction) of the M-NC was analysed using XPS (X-ray photoelectron spectroscopy). The obtained relations were verified by VASP (Vienna Ab-initio Simulation Package).
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The content of Cu2+ in lubricating oil and lubricant temperature are important indicators predicting mechanical failure. Therefore, developing a nontoxic fluorescence probe is necessary to detect Cu2+ and temperature in lubricating oil. The lead-free inorganic double perovskite nanocrystals (NCs) Cs2AgInCl6 are potential candidates. However, the low fluorescence intensity and the high excitation energy required of Cs2AgInCl6 NCs limit their practical applications. In this study, Bi3+ and Tb3+ were successfully co-doped into Cs2AgInCl6 NCs via the hot-injection method. The doping of Bi3+ produces a broad emission originating from self-trapped excitons and reduces the excitation energy, allowing commercial LEDs as excitation sources. Tb3+ ions doping offers characteristic emission peaks (5D0-7FJ) of Tb3+ ions and improves the fluorescence intensity of Cs2AgInCl6 NCs. Furthermore, the Cs2AgInCl6: Bi3+/Tb3+ NCs have been employed as optical thermometry, which provide a temperature calibration curve with the maximum absolute and relative sensitivities of 2.15% K-1 at 350 K and 2.25% K-1 at 303 K in the temperature range of 303-423 K, respectively. Finally, the nanocrystals have been applied to detect Cu2+ in lubricating oil. The fluorescent probe shows a good detection sensitivity of 8.94 × 10-4 nM-1 and a low detection limit of 14.3 nM in the range of 10-300 nM. This work not merely offers a novel way for improving the luminescence performances of double perovskite NCs Cs2AgInCl6, but broadens their potential for detection of Cu2+ and temperature.
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In this study, intense red and extremely weak green up-conversion (UC) luminescence was obtained in BaGd2O4: x mol% Yb3+/y mol% Er3+ phosphors under the excitations of 980 nm and 1550 nm. The corresponding maximum integrated intensity ratios of the red to green UC emissions are 50.3 and 158.7, respectively. The UC luminescence mechanisms upon different excitations were discussed. It was confirmed that two-photon and three-photon processes were responsible for both the red and green UC emissions excited at 980 nm and 1550 nm, respectively. The energy transfer efficiency from Er3+ to Yb3+ was calculated according to the fluorescence lifetime measurement under 1550 nm excitation. Temperature sensing based upon the thermally coupled energy levels 2H11/2/4S3/2 as well as thermally coupled Stark sublevels of 4F9/2 level of Er3+ was investigated under the excitation of 980 nm. The maximum absolute sensitivities were respectively obtained to be 0.42% K-1 at 573 K and 0.18% K-1 at 298 K. Our results indicated that BaGd2O4: Yb3+/Er3+ phosphors might be a kind of promising red UC phosphors with optical temperature measurement function.
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Energy harvesting (EH) is a potential solution to enhance the node sustainability and prolong the network lifetime of cognitive radio sensor networks (CRSNs). However, CRSNs nodes can only harvest energy from the direct link with energy sources, and severe path loss results in low energy utilization ratio. To solve the above problem, intelligent reflecting surface (IRS) is introduced, and a shared reflection coefficient matrix-based EH scheme is proposed for IRS-aided CRSNs in this paper. An optimization problem with the objective of maximizing the total amount of energy harvested by all CRSNs nodes is formulated, and by optimally adjusting the IRS reflection coefficient, CRSNs nodes can harvest energy from both the direct link and the cascaded reflection link via IRS, which increases the amount of harvested energy. In addition, a subsurface partition-based EH scheme is proposed to reduce the additional computational complexity brought by increasing IRS elements or CRSNs nodes. Simulation results show that the proposed schemes can both dramatically improve energy utilization ratio, and the subsurface partition-based EH scheme will bring in less than 1 percent performance loss when compared with the other scheme, i.e., reasonable subsurface partition can achieve a balance between harvested energy and computational complexity.