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LATTICE LOCATION DETERMINATION OF TRACE AMOUNT CARBON IN GALLIUM ARSENIDE BY THEORETICAL CALCULATION OF CPAA WITH CHANNELING
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作者 韦伦存 包尚联 +1 位作者 杨其湘 杨熙宏 《Nuclear Science and Techniques》 SCIE CAS CSCD 1991年第4期211-219,共9页
Combining the charged particle activation analysis (CPAA) and the (?)hanneling technique, partial concentrations of carbon on different crystal lattice locations of GaAs were calculated. The results show that at lower... Combining the charged particle activation analysis (CPAA) and the (?)hanneling technique, partial concentrations of carbon on different crystal lattice locations of GaAs were calculated. The results show that at lower total concentration (≈0.3 ppm), carbon atoms occupy principally the octahedral and displaced octahedral interstitial positions, but at higher total concentration (≈2 ppm), the substitutional carbon plays a principal role. 展开更多
关键词 cpaa CHANNELING technique IMPURITY carbon GAAS
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云通信服务垃圾信息问题治理研究
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作者 姚晓天 熊惟楚 《邮电设计技术》 2023年第10期70-73,共4页
当前,云通信服务正在快速兴起,相关市场逐步壮大,为广大用户带来了通信便利,降低了中小企业通信成本,助力数字经济发展。同时,此类服务也伴随着骚扰电话、垃圾短信等垃圾信息扰民问题,引起了部分用户的投诉和社会舆情。针对云通信服务... 当前,云通信服务正在快速兴起,相关市场逐步壮大,为广大用户带来了通信便利,降低了中小企业通信成本,助力数字经济发展。同时,此类服务也伴随着骚扰电话、垃圾短信等垃圾信息扰民问题,引起了部分用户的投诉和社会舆情。针对云通信服务快速发展态势,对主要的服务架构与应用场景进行系统化梳理,分析造成垃圾信息问题的关键环节,并给出了监管治理、经营合规和创新发展等建议,鼓励云通信服务合规发展,有效赋能实体经济。 展开更多
关键词 云通信 网络安全 cpaaS 骚扰电话 垃圾短信
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C_(60)与含受电子生色基团聚合物的电荷转移现象 被引量:2
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作者 邱健 姚光庆 +1 位作者 周锡煌 李福绵 《高分子学报》 SCIE CAS CSCD 北大核心 1997年第3期367-370,共4页
C60与含受电子生色基团聚合物的电荷转移现象邱健姚光庆周锡煌李福绵(北京大学化学与分子工程学院北京100871)关键词C60,聚[N(4氰基苯基)丙烯酰胺],电荷转移现象,荧光光谱随着对球壳烯性质的深入认识,球... C60与含受电子生色基团聚合物的电荷转移现象邱健姚光庆周锡煌李福绵(北京大学化学与分子工程学院北京100871)关键词C60,聚[N(4氰基苯基)丙烯酰胺],电荷转移现象,荧光光谱随着对球壳烯性质的深入认识,球壳烯与电子给、受体的电荷转移现象日... 展开更多
关键词 电荷转移现象 荧光光谱 碳60 P(cpaa) 聚合物
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DDM-PMDA-HAB噁唑酰亚胺共聚物的合成及其耐热性
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作者 高原 张茂根 +1 位作者 王炳祥 沈健 《应用化学》 CAS CSCD 北大核心 2006年第9期1027-1031,共5页
用4,4′-二氨基二苯基甲烷(DDM),3,3′-二羟基联苯胺(HAB),与均苯四甲酸二酐(PMDA)在N,N-二甲基乙酰胺中室温缩聚,制备了3种共聚酰胺酸(CPAA);CPAA膜经热处理失水环化,形成共聚酰亚胺(CVI);在N2气下经500℃热处理,... 用4,4′-二氨基二苯基甲烷(DDM),3,3′-二羟基联苯胺(HAB),与均苯四甲酸二酐(PMDA)在N,N-二甲基乙酰胺中室温缩聚,制备了3种共聚酰胺酸(CPAA);CPAA膜经热处理失水环化,形成共聚酰亚胺(CVI);在N2气下经500℃热处理,重排转变为DDM.PMDA.HAB噁唑酰亚胺共聚物(CPBI)。ATR光谱显示了CPI和CPBI膜的特征结构。TGA分析佐证了噁唑化转变。CPBI膜均显示优良的耐热性(用质量损失5%时的温度Td表示)。比相应的CPI高93~138℃;比二元聚合物PMDA-HAB聚苯并噁唑(PBO)高65~86℃。廉价的DDM在二胺单体中所占摩尔分数为75%时,CPBI仍保持优良的耐热性(Td为573℃)。 展开更多
关键词 共聚酰胺酸 共聚酰亚胺 嚼唑酰亚胺共聚物 聚苯并嚼唑 制备 耐热性
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Wireless Transmission Based Image Quality Analysis Using Uni-Level Haar Wavelet Transform 被引量:1
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作者 K. Senthamilselvan Lakshmi Dhevi 《Circuits and Systems》 2016年第8期1816-1821,共6页
This article deals with picture excellence examination by different parameters utilizing uni-level Haar wavelet transmission in excess of remote channel. The quality is analyzed based on power. The goal is towards red... This article deals with picture excellence examination by different parameters utilizing uni-level Haar wavelet transmission in excess of remote channel. The quality is analyzed based on power. The goal is towards reducing absolute power assigned in favour of picture compression and communication, while power in favour of every bit is reserved at prearranged value. Two Power Algorithms were presented. The greatest iterative power control calculation and Minimum Power Adaptation Algorithm (MPAA) are proposed. Those algorithms methodology was utilized for improving the aggregate power dispensed for multimedia such as picture because of input compression and transmission focus towards a settled bit source mutilation. Simulations were performed utilizing Haar wavelet than Additive White Gaussian Ration (AWGN) channel. Different picture excellence parameters, for example, Peak Signal to Noise Ratio (PSNR), M-Normalized Cross-Correla- tion, Average Difference;Structural Content parameters, for example, Maximum Difference, Normalized Absolute Error, Elapsed Time, CPU time, demonstrate a improved presentation with MPAA, Maximum Power Adaptation Algorithms (MAPAA) instead of Conventional Power Adaptation Algorithm (CPAA). 展开更多
关键词 Uni-Level Haar Wavelet Maximum Minimum Additive White Gaussian Ration (AWGN) Minimum Power Adaptation Algorithm (MPAA) Maximum Power Adaptation Algorithms (MAPAA) Conventional Power Adaptation Algorithm (cpaa)
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