A new shadow mask plasma display panel （SMPDP） is presented in this article. The unsymmetrical geometry structure of the discharge cell is its main feature. A macro-cell with a ratio of 40：1 was designed and fabric...A new shadow mask plasma display panel （SMPDP） is presented in this article. The unsymmetrical geometry structure of the discharge cell is its main feature. A macro-cell with a ratio of 40：1 was designed and fabricated. The geometrical parameters and electrode＇s structure of the discharge cell of the unsymmetrical SMPDP were optimized. Compared with current SMPDP, its luminous efficiency was obviously improved. Then a 32-inch wide video graphics array （WVGA） unsymmetrical SMPDP with a luminous efficacy of 1.8 Lm/W was produced.展开更多
In this paper, a new equivalent circuit model of GaN-based light emitting diodes （LEDs） is established. The impact of the series resistance to luminous efficacy is simulated using the MATLAB software. GaN-based LEDs...In this paper, a new equivalent circuit model of GaN-based light emitting diodes （LEDs） is established. The impact of the series resistance to luminous efficacy is simulated using the MATLAB software. GaN-based LEDs with different n- contact electrode materials （LEDs with Ni/Au and LEDs with Cr/Au） are fabricated. By comparing and analyzing the results of performances, we concluded that both the series resistance and the carrier loss could affect the luminous efficacy severely. LEDs with lower series resistance have higher luminous efficacy and its efficiency droop is alleviated simultaneously. To improve luminous efficacy, the fabrication process should be optimized for lower series resistance.展开更多
PURPOSE:To review the efficacy and patterns of failure in average-risk medulloblastoma patients treated withconcurrent chemotherapy and reduced-dose cranial spinal irradiation and a conformal tumor bed boost.METH-ODS ...PURPOSE:To review the efficacy and patterns of failure in average-risk medulloblastoma patients treated withconcurrent chemotherapy and reduced-dose cranial spinal irradiation and a conformal tumor bed boost.METH-ODS AND MATERIALS:Thirty-three patients with average risk(defined as<==1.5 cm(2)of residual tumorafter resection,age>3 years,and no involvement of the cerebrospinal fluid or spine)medulloblastoma werediagnosed at our institution between January 1994 and December 2001.They were enrolled in an institutional展开更多
The photometric characteristics of high-power white light-emitting diode （LED） devices are investigated. A theoretical model for the luminous efficacy o[ high-power white LED devices and LED systems is proposed. Wit...The photometric characteristics of high-power white light-emitting diode （LED） devices are investigated. A theoretical model for the luminous efficacy o[ high-power white LED devices and LED systems is proposed. With the proposed theoretical model, the mechanism of the luminous efficacy decrease is explained. Meanwhile, the model can be used to estimate the luminous efficacy oF LEDs under general operation conditions, such as different operation temperatures and injection currents. The wide validity of the luminous efficacy model is experimentally verified through the measurements of different types of LEDs. The experimental results demonstrate a high estimation accuracy. The proposed models not only can be applied to estimate the LED photometric performance, but also is helpful for reliability research of LEDs.展开更多
Today, energy saving and emission reduction are two big global issues. Power artificial lighting currently accounts for about 20% of the total global electricity consumption [1]. Solid-state lighting based on light-em...Today, energy saving and emission reduction are two big global issues. Power artificial lighting currently accounts for about 20% of the total global electricity consumption [1]. Solid-state lighting based on light-emitting diodes (LEDs) is bringing about a revolution in energy-efficient lighting, and the lighting industry is transformed into a rapidly growing business sector [2,3]. The solid-state lighting technology is basically based on phosphor- converted white LEDs (pc-LEDs), which are commonly fabricated by using the combination of InGaN blue-emitting LED chips and luminescent materials as color converters [4,5], Luminescent materials play a critical role in fabricating high-performance LED devices, which is strongly linked to LED's luminous efficacy, stability, color rendering index (CRI), correlated color temperature (CCT) and operation lifetime [6-8]. Therefore, the discovery of more efficient desirable phosphor materials is essential.展开更多
We packaged a series of high power white LEDs by covering the blue LED chips with yellow phosphor, red phosphor and the two phosphors mixed by appropriate mass ratio, respectively, and discussed the excitation and emi...We packaged a series of high power white LEDs by covering the blue LED chips with yellow phosphor, red phosphor and the two phosphors mixed by appropriate mass ratio, respectively, and discussed the excitation and emission spectrum of yellow phosphor and red phosphor and the characteristics of the LEDs. We found that the luminous efficacy of the white LEDs covered with the two phosphors mixed by appropriate mass ratio was lower than that of the white LEDs covered with yellow phosphor, but the color rendering index was improved observably.展开更多
搭建由半导体制冷片和光谱仪组成的LED变温发光特性测试系统，使用多通道温度测试仪记录芯片工作温度，得到LED芯片在30-80℃范围内的发光特性与温度的关系。结果表明：在输入电流恒定时，随着芯片材料温度的不断升高，LED的电功率和光...搭建由半导体制冷片和光谱仪组成的LED变温发光特性测试系统，使用多通道温度测试仪记录芯片工作温度，得到LED芯片在30-80℃范围内的发光特性与温度的关系。结果表明：在输入电流恒定时，随着芯片材料温度的不断升高，LED的电功率和光功率降低，LED光效下降趋势明显；同时由于材料禁带宽度减小， GaN LED的蓝光峰值波长发生红移；通过上述测试，利用数值拟合方式得到了芯片发光特性与温度之间的函数关系。展开更多
基金the Programme of Introducing Talents of Discipline to Universities,Project of the Ministry of Education of China(No.B07027)National Natural Science Foundation of China(No.60271016)Young Elitist Education and Research Fund of Southeast University(No.4006001007)
文摘A new shadow mask plasma display panel （SMPDP） is presented in this article. The unsymmetrical geometry structure of the discharge cell is its main feature. A macro-cell with a ratio of 40：1 was designed and fabricated. The geometrical parameters and electrode＇s structure of the discharge cell of the unsymmetrical SMPDP were optimized. Compared with current SMPDP, its luminous efficiency was obviously improved. Then a 32-inch wide video graphics array （WVGA） unsymmetrical SMPDP with a luminous efficacy of 1.8 Lm/W was produced.
基金supported by the National Natural Science Foundation of China(Grant No.11204009)
文摘In this paper, a new equivalent circuit model of GaN-based light emitting diodes （LEDs） is established. The impact of the series resistance to luminous efficacy is simulated using the MATLAB software. GaN-based LEDs with different n- contact electrode materials （LEDs with Ni/Au and LEDs with Cr/Au） are fabricated. By comparing and analyzing the results of performances, we concluded that both the series resistance and the carrier loss could affect the luminous efficacy severely. LEDs with lower series resistance have higher luminous efficacy and its efficiency droop is alleviated simultaneously. To improve luminous efficacy, the fabrication process should be optimized for lower series resistance.
文摘PURPOSE:To review the efficacy and patterns of failure in average-risk medulloblastoma patients treated withconcurrent chemotherapy and reduced-dose cranial spinal irradiation and a conformal tumor bed boost.METH-ODS AND MATERIALS:Thirty-three patients with average risk(defined as<==1.5 cm(2)of residual tumorafter resection,age>3 years,and no involvement of the cerebrospinal fluid or spine)medulloblastoma werediagnosed at our institution between January 1994 and December 2001.They were enrolled in an institutional
基金Supported by the National Natural Science Foundation of China under Grant Nos 51307113 and 51407124the Natural Science Foundation of Jiangsu Province under Grant No BK20130307
文摘The photometric characteristics of high-power white light-emitting diode （LED） devices are investigated. A theoretical model for the luminous efficacy o[ high-power white LED devices and LED systems is proposed. With the proposed theoretical model, the mechanism of the luminous efficacy decrease is explained. Meanwhile, the model can be used to estimate the luminous efficacy oF LEDs under general operation conditions, such as different operation temperatures and injection currents. The wide validity of the luminous efficacy model is experimentally verified through the measurements of different types of LEDs. The experimental results demonstrate a high estimation accuracy. The proposed models not only can be applied to estimate the LED photometric performance, but also is helpful for reliability research of LEDs.
文摘Today, energy saving and emission reduction are two big global issues. Power artificial lighting currently accounts for about 20% of the total global electricity consumption [1]. Solid-state lighting based on light-emitting diodes (LEDs) is bringing about a revolution in energy-efficient lighting, and the lighting industry is transformed into a rapidly growing business sector [2,3]. The solid-state lighting technology is basically based on phosphor- converted white LEDs (pc-LEDs), which are commonly fabricated by using the combination of InGaN blue-emitting LED chips and luminescent materials as color converters [4,5], Luminescent materials play a critical role in fabricating high-performance LED devices, which is strongly linked to LED's luminous efficacy, stability, color rendering index (CRI), correlated color temperature (CCT) and operation lifetime [6-8]. Therefore, the discovery of more efficient desirable phosphor materials is essential.
基金Project supported by the Fund of the Institute of Semiconductors,Chinese Academy of Sciences(No.ISCAS2008T14)
文摘We packaged a series of high power white LEDs by covering the blue LED chips with yellow phosphor, red phosphor and the two phosphors mixed by appropriate mass ratio, respectively, and discussed the excitation and emission spectrum of yellow phosphor and red phosphor and the characteristics of the LEDs. We found that the luminous efficacy of the white LEDs covered with the two phosphors mixed by appropriate mass ratio was lower than that of the white LEDs covered with yellow phosphor, but the color rendering index was improved observably.
文摘搭建由半导体制冷片和光谱仪组成的LED变温发光特性测试系统，使用多通道温度测试仪记录芯片工作温度，得到LED芯片在30-80℃范围内的发光特性与温度的关系。结果表明：在输入电流恒定时，随着芯片材料温度的不断升高，LED的电功率和光功率降低，LED光效下降趋势明显；同时由于材料禁带宽度减小， GaN LED的蓝光峰值波长发生红移；通过上述测试，利用数值拟合方式得到了芯片发光特性与温度之间的函数关系。
