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等温退火对ZrCuAlNiCoNb非晶合金硬度和杨氏模量的影响
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作者 董明斌 李桢 +2 位作者 顾及 宋旼 阮建明 《粉末冶金材料科学与工程》 EI 北大核心 2013年第4期471-476,共6页
采用真空电弧熔炼结合水冷铜模吸铸法制备ZrCuAlNiCoNb大块非晶合金。采用XRD、AFM、SEM及纳米压痕分析手段研究等温退火对ZrCuAlNiCoNb非晶合金显微组织演变、硬度和杨氏模量的影响。结果表明,无论温度高低,退火均能使非晶合金中自由... 采用真空电弧熔炼结合水冷铜模吸铸法制备ZrCuAlNiCoNb大块非晶合金。采用XRD、AFM、SEM及纳米压痕分析手段研究等温退火对ZrCuAlNiCoNb非晶合金显微组织演变、硬度和杨氏模量的影响。结果表明,无论温度高低,退火均能使非晶合金中自由体积的数量减少。在低于玻璃化转变温度下退火,合金中自由体积数量下降,抑制了剪切带的形核,合金的硬度和杨氏模量随退火时间的增加而提高;在高于玻璃化转变温度下退火,短时间即可诱发纳米晶化,合金的硬度和杨氏模量均先增加,达到峰值后下降。ZrCuAlNiCoNb非晶合金力学性能的演变趋势是自由体积演变和纳米晶形核共同作用的结果。 展开更多
关键词 非晶合金 等温退火 弹性模量 硬度
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漏洞中的迷失
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作者 董明斌 《网管员世界》 2007年第2期58-60,共3页
如今,安全漏洞已经成为互联网信息安全隐患的最大本源,堪称“万恶之源”。2006年,CSI/FBI的报告中指出安全事件造成的52,494,290美元的经济损失都与安全漏洞相关。已经大大超过总损失的一半。这个损失能否降低?
关键词 安全漏洞 经济损失 安全隐患 安全事件 互联网 FBI CSI 总损失
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Reputation evaluation method for open multi-agent systems
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作者 金福生 董明斌 +1 位作者 牛振东 张全新 《Journal of Beijing Institute of Technology》 EI CAS 2013年第1期75-80,共6页
A reputation evaluation method based on multi-dimensional information representation and correlative algorithm is proposed for open multi-agent systems. First, a vector model is estab- lished to represent the reputati... A reputation evaluation method based on multi-dimensional information representation and correlative algorithm is proposed for open multi-agent systems. First, a vector model is estab- lished to represent the reputation related information. Second, a vector based reputation model "TRUST" is put forward to evaluate the reputation of agents. Finally, a correlative algorithm for se- lecting the most appropriate service provider is proposed. Simulation results indicate that the method can quickly and accurately to achieve the aim of adaptive immunity to reputation fraud and improving the average gain that service consumer agents obtained. 展开更多
关键词 REPUTATION reputation fraud VECTOR correlation algorithm
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Trivalent Yb/Ho/Ce tri-doped core/shell NaYF4 nanoparticles for tunable upconversion luminescence from green to red 被引量:3
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作者 董明斌 李心悦 +3 位作者 迟逢逢 韦先涛 尹民 陈永虎 《Journal of Rare Earths》 SCIE EI CAS CSCD 2017年第7期629-636,共8页
Three types of β-NaYF_4nanoparticles, uncoated core(NaYF_4:Yb/Ho/Ce), single-layer coated core@shell(NaYF_4:Yb/Ho/Ce@NaYF_4:Yb) and double-layer coated core@shell@shell(NaYF_4:Yb/Ho@NaYF_4:Yb@NaYF_4:Yb) w... Three types of β-NaYF_4nanoparticles, uncoated core(NaYF_4:Yb/Ho/Ce), single-layer coated core@shell(NaYF_4:Yb/Ho/Ce@NaYF_4:Yb) and double-layer coated core@shell@shell(NaYF_4:Yb/Ho@NaYF_4:Yb@NaYF_4:Yb) with Ce^(3+) doped in core, first and second shell, respectively, were synthesized through solvothermal method to investigate the cross-relaxation between Ho^(3+) and Ce^(3+) for the tunable upconversion luminescence. By doping Ce^(3+) into different layers with different doping concentrations, a systematical investigation on the tunable upconversion luminescence from green to red was conducted. The results showed that a remarkable color tuning could be achieved from green to red when increasing the doping concentration of Ce^(3+) in the same layer of Ho^(3+). And if Ce^(3+) and Ho^(3+) were separated in different layers, the color tuning would be depressed significantly due to the reduced cross-relaxation between Ho^(3+) and Ce^(3+). Moreover, the UC emission intensity of core@shell and core@shell@shell was enhanced significantly compared with that of unmodified core nanoparticles. 展开更多
关键词 core@shell structure upconversion color tuning rare earths
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