The polycrystalline Sr_9Ca(PO_4)_6Cl_2:Eu has been synthesized by solid state reaction.The reaction condition,the appropriate raw materials and their quantity used,which may affect the photostimulable luminescence (PS...The polycrystalline Sr_9Ca(PO_4)_6Cl_2:Eu has been synthesized by solid state reaction.The reaction condition,the appropriate raw materials and their quantity used,which may affect the photostimulable luminescence (PSL),have been systematically inves- tigated.The properties of this PSL phosphor as a material for storing and reproducing the X-ray image in computer-aided radiography have been reported briefly.展开更多
In this paper, a model of cavitational luminescence (CL) and sonoluminescence (SL) is developed. The basis of the model is the PeTa (Perel’man-Tatartchenko) effect—a characteristic radiation under first-order phase ...In this paper, a model of cavitational luminescence (CL) and sonoluminescence (SL) is developed. The basis of the model is the PeTa (Perel’man-Tatartchenko) effect—a characteristic radiation under first-order phase transitions. The main role is given to the liquid, which is where the cavitation occurs. The evaporation of the liquid and subsequent vapor condensation inside the bubble are responsible for the CL and SL. Apparently, the dissolved gases and other impurities in the liquid are responsible for peaks that appear at the background of the main spectrum. They most likely are excited by a shock wave occurred during cavitation. The model explains the main experimental data. Thus, no mystery, no plasma, no Hollywood.展开更多
A two-dimensional(2D) 44 topological ZnⅡ coordination polymer {[Zn2Cl2(L)(4bpy)2]}∞(H2L = anthracene-9,10-dicarboxylic acid, 4bpy = 4,4ˊ-bipyridine) based on binuclear [Zn2Cl2] nodes has been synthesized an...A two-dimensional(2D) 44 topological ZnⅡ coordination polymer {[Zn2Cl2(L)(4bpy)2]}∞(H2L = anthracene-9,10-dicarboxylic acid, 4bpy = 4,4ˊ-bipyridine) based on binuclear [Zn2Cl2] nodes has been synthesized and characterized by IR, elemental analysis, X-ray powder diffraction and single-crystal X-ray diffraction analysis. Moreover, the luminescent properties of the correspon- ding compound have been briefly investigated.展开更多
This paper is a continuation of one published in this journal nine months ago. The two papers present a model of cavitational luminescence (CL), multi-bubble sonoluminescence (MBSL), one-bubble sonoluminescence (OBSL)...This paper is a continuation of one published in this journal nine months ago. The two papers present a model of cavitational luminescence (CL), multi-bubble sonoluminescence (MBSL), one-bubble sonoluminescence (OBSL), and laser-induced bubble luminescence (LIBL). The basis of this model is the PeTa (Perel’man-Tatartchenko) effect, a nonequilibrium characteristic radiation under first-order phase transitions, especially vapour condensation. In this model, the main role is given to the liquid, where the evaporation, condensation, flash, and subsequent collapse of bubbles occur. The instantaneous vapour condensation inside the bubble is a reason for the CL/MBSL/OBSL/LIBL. Apparently, the dissolved gases and other impurities in the liquid are responsible for peaks that appear at the background of the main spectrum. They are most likely excited by a shock wave occurred during the collapse. This paper, in contrast to the previous one, presents a slightly expanded model that explains additional experimental data concerning especially the LIBL spectrum. As a result, today we are not aware of any experimental data that would contradict the PeTa model, and we continue to assert that there is no mystery to the CL/MBSL/OBSL/LIBL phenomena, as well as no reason to hope that they can be used for high-temperature chemical reactions, and even more so for a thermonuclear ones.展开更多
This paper is the third in a series published in this journal during 2017-2018. These three papers present various stages in the development of the PeTa model for phenomena of the same physical nature: cavitational lu...This paper is the third in a series published in this journal during 2017-2018. These three papers present various stages in the development of the PeTa model for phenomena of the same physical nature: cavitational luminescence (CL), multi-bubble sonoluminescence (MBSL), single-bubble sonoluminescence (SBSL), and laser-induced bubble luminescence (LIBL). The basis of this model is the PeTa (Perel’man-Tatartchenko) effect—a nonequilibrium characteristic radiation under first-order phase transitions, for instance, vapour condensation. The third iteration of this model “Vapour bubble luminescence” (VBL) is presented in this paper. The essence of this model is as follows: with a local decrease of pressure or an increase of temperature in a tiny volume of the liquid, one or several bubbles filled with vapour will appear. Subsequently, a very rapid increase in pressure or a decrease in temperature of the bubble leads to super-saturation of the vapour inside the bubble, followed by its instantaneous condensation with the emission of condensation energy (this is the PeTa effect). A sharp decrease in pressure causes the collapse of the bubble accompanied by a shock wave in the liquid. VBL model is conveniently represented on the solid-liquid-vapour phase diagram. A better understanding of the physical nature of the phenomena under consideration could help to find their useful applications. To develop this idea further, we propose a design of a cavity-free pulsed laser on the basis of CL/MBSL/SBSL. An analysis of LIBL in cryogenic liquids is also given in this paper.展开更多
We investigated the cathode luminescence characteristics of CsI(Na)and CsI(Tl)crystals by the spectrum and structure properties at room temperature.We fabricated three different sizes of CsI(Na)and CsI(Tl)crystals and...We investigated the cathode luminescence characteristics of CsI(Na)and CsI(Tl)crystals by the spectrum and structure properties at room temperature.We fabricated three different sizes of CsI(Na)and CsI(Tl)crystals and measured their luminescence spectra under cathode rays.We found that CsI(Na)cathode luminescence peaks appear at 420 and 305 nm,and CsI(Tl)cathode luminescence peaks are 540 and 410 nm,the grain size affects CsI(Na)luminescence significantly,and the Na-related420 nm luminescence intensified relatively when the average grain size reaches^20μm,which becomes weak when the grain size is down to nano-scale.But the cathode luminescence spectra of CsI(Tl)crystals with different size have no obvious changes.Our explanations for these phenomena are that the different impurities in the same host material CsI lead to different luminescence mechanisms.These cathode luminescence characteristics indicate the suitability of CsI(Na)and CsI(Tl)crystals to match photomultiplier tube for large area crystal detector development.展开更多
Ca2BO3Cl:Ce3+, Ca2BO3Cl:Tb3+, and Ca2BO3Cl:Ce3+, Tb3+ phosphors are synthesized by a high temperature solid-state reaction. The emission intensity of Ce3+ or Tb3+ in Ca2BO3Cl is influenced by the Ce3+ or Tb3...Ca2BO3Cl:Ce3+, Ca2BO3Cl:Tb3+, and Ca2BO3Cl:Ce3+, Tb3+ phosphors are synthesized by a high temperature solid-state reaction. The emission intensity of Ce3+ or Tb3+ in Ca2BO3Cl is influenced by the Ce3+ or Tb3+ doping content, and the optimum concentrations of Ce3+ and Tb3+ are 0.03 tool and 0.05 mol, respectively. The concentration quenching effect of Ce3+ or Tb3+ in Ca2BO3Cl occurs, and the concentration quenching mechanism is d-d interaction for either Ce3+ or Tb3+. The Ca21303Cl:Ce3+, Tb3+ can produce colour emission from blue to green by properly tuning the relative ratio between Ce3+ and Tb3+, and the emission intensity of Tb3+ in Ca2BO3Cl can be enhanced by the energy transfer from Ce3+ to Tb3+. The results indicate that Ca2BO3Cl:Ce3+, Tb3+ may be a promising double emission phosphor for UV-based white light emitting diodes.展开更多
A novel white emitting phosphor Ca2PO4Cl:Dy^3+ was synthesized by a solid state method. The luminescence, concentration quenching and thermal stability of Ca2PO4Cl:Dy^3+ were investigated. Ca2PO4Cl:Dy^3+ showed ...A novel white emitting phosphor Ca2PO4Cl:Dy^3+ was synthesized by a solid state method. The luminescence, concentration quenching and thermal stability of Ca2PO4Cl:Dy^3+ were investigated. Ca2PO4Cl:Dy^3+ showed three emission peaks, which were located at 483, 575 and 660 nm. Though the ratio of yellow to blue emission intensities showed a similar value, the intensities of yellow and blue peaks were influenced by Dy^3+ concentration, and the concentration quenching effect was observed. The emission intensity of Ca2PO4Cl:Dy^3+ as a function of temperature was explored and the emission intensity(at 150 °C) of Ca2PO4Cl:Dy^3+ was 90.0% of the value at 25 °C, and activation energy was 0.18 eV. The results indicated that Ca2PO4Cl:Dy^3+ might be conducive to development of white LEDs.展开更多
文摘The polycrystalline Sr_9Ca(PO_4)_6Cl_2:Eu has been synthesized by solid state reaction.The reaction condition,the appropriate raw materials and their quantity used,which may affect the photostimulable luminescence (PSL),have been systematically inves- tigated.The properties of this PSL phosphor as a material for storing and reproducing the X-ray image in computer-aided radiography have been reported briefly.
文摘In this paper, a model of cavitational luminescence (CL) and sonoluminescence (SL) is developed. The basis of the model is the PeTa (Perel’man-Tatartchenko) effect—a characteristic radiation under first-order phase transitions. The main role is given to the liquid, which is where the cavitation occurs. The evaporation of the liquid and subsequent vapor condensation inside the bubble are responsible for the CL and SL. Apparently, the dissolved gases and other impurities in the liquid are responsible for peaks that appear at the background of the main spectrum. They most likely are excited by a shock wave occurred during cavitation. The model explains the main experimental data. Thus, no mystery, no plasma, no Hollywood.
基金Supported by the key project of Science,the Technology Department of Henan province(No.112102210371)the science and technology research projects of Education Department of Henan province(No.12B150003)
文摘A two-dimensional(2D) 44 topological ZnⅡ coordination polymer {[Zn2Cl2(L)(4bpy)2]}∞(H2L = anthracene-9,10-dicarboxylic acid, 4bpy = 4,4ˊ-bipyridine) based on binuclear [Zn2Cl2] nodes has been synthesized and characterized by IR, elemental analysis, X-ray powder diffraction and single-crystal X-ray diffraction analysis. Moreover, the luminescent properties of the correspon- ding compound have been briefly investigated.
文摘This paper is a continuation of one published in this journal nine months ago. The two papers present a model of cavitational luminescence (CL), multi-bubble sonoluminescence (MBSL), one-bubble sonoluminescence (OBSL), and laser-induced bubble luminescence (LIBL). The basis of this model is the PeTa (Perel’man-Tatartchenko) effect, a nonequilibrium characteristic radiation under first-order phase transitions, especially vapour condensation. In this model, the main role is given to the liquid, where the evaporation, condensation, flash, and subsequent collapse of bubbles occur. The instantaneous vapour condensation inside the bubble is a reason for the CL/MBSL/OBSL/LIBL. Apparently, the dissolved gases and other impurities in the liquid are responsible for peaks that appear at the background of the main spectrum. They are most likely excited by a shock wave occurred during the collapse. This paper, in contrast to the previous one, presents a slightly expanded model that explains additional experimental data concerning especially the LIBL spectrum. As a result, today we are not aware of any experimental data that would contradict the PeTa model, and we continue to assert that there is no mystery to the CL/MBSL/OBSL/LIBL phenomena, as well as no reason to hope that they can be used for high-temperature chemical reactions, and even more so for a thermonuclear ones.
文摘This paper is the third in a series published in this journal during 2017-2018. These three papers present various stages in the development of the PeTa model for phenomena of the same physical nature: cavitational luminescence (CL), multi-bubble sonoluminescence (MBSL), single-bubble sonoluminescence (SBSL), and laser-induced bubble luminescence (LIBL). The basis of this model is the PeTa (Perel’man-Tatartchenko) effect—a nonequilibrium characteristic radiation under first-order phase transitions, for instance, vapour condensation. The third iteration of this model “Vapour bubble luminescence” (VBL) is presented in this paper. The essence of this model is as follows: with a local decrease of pressure or an increase of temperature in a tiny volume of the liquid, one or several bubbles filled with vapour will appear. Subsequently, a very rapid increase in pressure or a decrease in temperature of the bubble leads to super-saturation of the vapour inside the bubble, followed by its instantaneous condensation with the emission of condensation energy (this is the PeTa effect). A sharp decrease in pressure causes the collapse of the bubble accompanied by a shock wave in the liquid. VBL model is conveniently represented on the solid-liquid-vapour phase diagram. A better understanding of the physical nature of the phenomena under consideration could help to find their useful applications. To develop this idea further, we propose a design of a cavity-free pulsed laser on the basis of CL/MBSL/SBSL. An analysis of LIBL in cryogenic liquids is also given in this paper.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.11QG14)
文摘We investigated the cathode luminescence characteristics of CsI(Na)and CsI(Tl)crystals by the spectrum and structure properties at room temperature.We fabricated three different sizes of CsI(Na)and CsI(Tl)crystals and measured their luminescence spectra under cathode rays.We found that CsI(Na)cathode luminescence peaks appear at 420 and 305 nm,and CsI(Tl)cathode luminescence peaks are 540 and 410 nm,the grain size affects CsI(Na)luminescence significantly,and the Na-related420 nm luminescence intensified relatively when the average grain size reaches^20μm,which becomes weak when the grain size is down to nano-scale.But the cathode luminescence spectra of CsI(Tl)crystals with different size have no obvious changes.Our explanations for these phenomena are that the different impurities in the same host material CsI lead to different luminescence mechanisms.These cathode luminescence characteristics indicate the suitability of CsI(Na)and CsI(Tl)crystals to match photomultiplier tube for large area crystal detector development.
基金Project supported by the National Basic Research Program of China(Grant No.2010CB327704)the National Natural Science Foundation for Distinguished Young Scholars of China(Grant No.60825407)+7 种基金the New Century Excellent Talents in University (Grant No.NCET-10-0220)the National Natural Science Foundation of China(Grant Nos.10974013,60978060,10804006,and 50902042)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20090009110027)Beijing Municipal Natural Science Foundation,China(Grant No.1102028)the Beijing Municipal Science & Technology Commission, China(Grant No.Z090803044009001)the Natural Science Foundation of Hebei Province,China(Grant No.E2010000283)the Fund from the Key Laboratory of Luminescence and Optical Information,Beijing Jiaotong University,Ministry of Education, China(Grant No.2010LOI12)the Excellent Doctor's Science and Technology Innovation Foundation of Beijing Jiaotong University(Grant No.2011YJS073)
文摘Ca2BO3Cl:Ce3+, Ca2BO3Cl:Tb3+, and Ca2BO3Cl:Ce3+, Tb3+ phosphors are synthesized by a high temperature solid-state reaction. The emission intensity of Ce3+ or Tb3+ in Ca2BO3Cl is influenced by the Ce3+ or Tb3+ doping content, and the optimum concentrations of Ce3+ and Tb3+ are 0.03 tool and 0.05 mol, respectively. The concentration quenching effect of Ce3+ or Tb3+ in Ca2BO3Cl occurs, and the concentration quenching mechanism is d-d interaction for either Ce3+ or Tb3+. The Ca21303Cl:Ce3+, Tb3+ can produce colour emission from blue to green by properly tuning the relative ratio between Ce3+ and Tb3+, and the emission intensity of Tb3+ in Ca2BO3Cl can be enhanced by the energy transfer from Ce3+ to Tb3+. The results indicate that Ca2BO3Cl:Ce3+, Tb3+ may be a promising double emission phosphor for UV-based white light emitting diodes.
基金supported by the National Natural Science Foundation of China(50902042)the Funds for Distinguished Young Scientists of Hebei Province,China(A2015201129)+2 种基金the Natural Science Foundation of Hebei Province,China(A2014201035,E2014201037)the Education Office Research Foundation of Hebei Province,China(ZD2014036,QN2014085)the Midwest Universities Comprehensive Strength Promotion Project
文摘A novel white emitting phosphor Ca2PO4Cl:Dy^3+ was synthesized by a solid state method. The luminescence, concentration quenching and thermal stability of Ca2PO4Cl:Dy^3+ were investigated. Ca2PO4Cl:Dy^3+ showed three emission peaks, which were located at 483, 575 and 660 nm. Though the ratio of yellow to blue emission intensities showed a similar value, the intensities of yellow and blue peaks were influenced by Dy^3+ concentration, and the concentration quenching effect was observed. The emission intensity of Ca2PO4Cl:Dy^3+ as a function of temperature was explored and the emission intensity(at 150 °C) of Ca2PO4Cl:Dy^3+ was 90.0% of the value at 25 °C, and activation energy was 0.18 eV. The results indicated that Ca2PO4Cl:Dy^3+ might be conducive to development of white LEDs.