Experimental Studies on Thermal and Electrical Properties of Platinum Nanofilms

We experimentally studied the in-plane thermal and electrical properties of a suspended platinum nanofilm in thickness of 15 nm. The measured results show that the in-plane thermal conductivity, the electrical conductivity and the resistance-temperature coefficient of the studied nanofilm are much less than those of the bulk material, while the Lorenz number is greater than the bulk value. Comparing with the results reported previously for the platinum nanofilm in thickness of 28 nm, we further find that the in-plane thermal conductivity, the electrical conductivity and the resistance-temperature coefficient decrease with the decreasing thickness of the nanotilm, while the Lorenz number increases with the decreasing thickness of the nanofilm. These results indicate that strong size effects exist on the in-plane thermal and electrical properties of platinum nanofilms.     

源气体对沉积的a-C∶F∶H薄膜结构的影响

采用微波电子回旋共振等离子体化学气相沉积(MWPECRCVD)方法,使用不同的源气体(CHF3CH4,CHF3C2H2,CHF3C6H6)体系制备了aC∶F∶H薄膜.由于CH4,C2H2,C6H6气体在等离子体中的分解反应不同导致了薄膜的沉积速率和结构上的差异.红外吸收谱的结果表明,用C6H6CHF3作为源气体沉积的薄膜中几乎不含H,而用C2H2CHF3所沉积的薄膜中的含氟量最高,其相应的CF振动峰位向高频方向偏移.薄膜的真空退火结果表明,aC∶F∶H薄膜的热稳定性除了取决于薄膜的CC键浓度外,还与CC键 关键词： 氟化非晶碳膜 电子回旋共振化学气相沉积 红外吸收光谱     

YZr2OZr3:Er3+纳米晶anti-Stokes发光性质的研究

采用均相沉积法制备了不同Er³⁺离子浓度掺杂的Y₂O₃纳米晶, 应用XRD，SEM和PL光谱对该体系材料进行了表征.在Y₂O₃:Er³⁺纳米材料体系中, 观察和研究了Stokes及anti-Stokes PL谱强度与Er³⁺离子摩尔浓度变化的关系, 当Er³⁺离子浓度为2.0mol%时, anti-Stokes PL强度最强.粉末X 关键词： 氧化钇纳米晶 anti-Stokes PL 双光子吸收     

Frame Wavelets with Compact Supports for L^2（R^n）

The construction of frame wavelets with compact supports is a meaningful problem in wavelet analysis. In particular, it is a hard work to construct the frame wavelets with explicit analytic forms. For a given n × n real expansive matrix A, the frame-sets with respect to A are a family of sets in R^n. Based on the frame-sets, a class of high-dimensional frame wavelets with analytic forms are constructed, which can be non-bandlimited, or even compactly supported. As an application, the construction is illustrated by several examples, in which some new frame wavelets with compact supports are constructed. Moreover, since the main result of this paper is about general dilation matrices, in the examples we present a family of frame wavelets associated with some non-integer dilation matrices that is meaningful in computational geometry.     

类氢及碱金属原子激发态寿命的半经典计算公式

根据对应原理,得到了类氢原子能态平均寿命半经典的计算公式τ(n,l),然后利用相对论单通道量子数亏损理论进行推广,得到用来计算考虑总角动量J的激发态寿命公式τ(n,l,l+1/2)和τ(n,l,l-1/2),利用单通道量子数亏损理论得到了碱金属原子n、l远大于1时激发态寿命的半经典公式τ(n.l)=τ0(m+M/nm/v/+M)2v7l(l+1/2)/n4,其计算结果和实验数据符合的很好.     

荧光光纤温度传感器激励光源的选择

本文分析计算了荧光光纤温度传感器的温敏元件——GsAlAs/GaAs双异质结半导体材料的荧光辐射效率与激励光波长的关系。讨论了温度测量范围及温敏元件GaAlAs层铝含量对激励光源的限制,在0～200℃测温范围内,若采用LED作激励光源,其峰值波长应在0.70～0.76μm之间选择。     

Independence of the brittle–ductile transition from the rubber particle size for impact‐modified poly(vinyl chloride)

A series of acrylic impact modifiers (AIMs) with different particle sizes ranging from 55.2 to 927.0 nm were synthesized by seeded emulsion polymerization, and the effect of the particle size on the brittle–ductile transition of impact‐modified poly(vinyl chloride) (PVC) was investigated. For each AIM, a series of PVC/AIM blends with compositions of 6, 8, 10, 12, and 15 phr AIM in 100 phr PVC were prepared, and the Izod impact strengths of these blends were tested at 23 °C. For AIMs with particle sizes of 55.2, 59.8, 125.2, 243.2, and 341.1 nm, the blends fractured in the brittle mode when the concentration of AIM was lower than 10 phr, whereas the blends showed ductile fracture when the AIM concentration reached 10 phr. It was concluded that the brittle–ductile transition of the PVC/AIM blends was independent of the particle size in the range of 55.2–341.1 nm. When the particle size was greater than 341.1 nm, however, the brittle–ductile transition shifted to a higher AIM concentration with an increase in the particle size. Furthermore, the critical interparticle distance was found not to be the criterion of the brittle–ductile transition for the PVC/AIM blends. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 696–702, 2006     

聚甲基丙烯酸甲酯掺杂Ce3+的飞秒激光三维信息存储

用飞秒激光(200 fs,1 kHz,800 nm)脉冲在掺杂稀土离子Ce3 的聚甲基丙烯酸甲酯(PMMA)膜中进行了光存储实验研究,包括对样品的吸收光谱、激光照射前后的电子旋转共振(Electron spin resonance,ESR)光谱的测量和讨论。结果表明掺杂稀土离子Ce3 的聚甲基丙烯酸甲酯膜具有较低的写入阈值,有利于高速、并行的三维光存储。实验结果采用传统光学显微镜并行读出。给出了四层存储结果(点间距和层间距分别是4μm和16μm),并讨论了脉冲能量的大小对空腔尺寸的影响,进行高密度存储时,在保证读出信号灰度值足够大的情况下,应选择尽量小的激光脉冲写入能量。实验结果表明这种材料可以应用于三维光信息存储。     

具有HfN/HfO2栅结构的p型MOSFET中的负偏置-温度不稳定性研究

研究了HfN/HfO₂高K栅结构p型金属-氧化物-半导体(MOS)晶体管(MOSFET)中，负 偏置-温度应力引起的阈值电压不稳定性(NBTI)特征.HfN/HfO₂高K栅结构的等效 氧化层厚度(EOT)为1.3nm，内含原生缺陷密度较低.研究表明，由于所制备的HfN/HfO₂ 高K栅结构具有低的原生缺陷密度，因此在p-MOSFET器件中观察到的NBTI属HfN/HfO2高K栅结构的本征特征，而非工艺缺陷引起的；进一步研究表明，该HfN/HfO₂高K栅结构中观察到的NBTI与传统的SiO₂基栅介质p-MOSFET器件中观察 到的NBTI具有类似的特征，可以被所谓的反应-扩散(R-D)模型表征： HfN/HfO₂ 栅结构p-MOSFET器件的NBTI效应的起源可以归为衬底注入空穴诱导的界面反应机理，即在负 偏置和温度应力作用下，从Si衬底注入的空穴诱导了Si衬底界面Si-H键断裂这一化学反应的 发生，并由此产生了Si^＋陷阱在Si衬底界面的积累和H原子在介质层内部的扩散 ，这种Si^＋陷阱的界面积累和H原子的扩散导致了器件NBTI效应的发生. 关键词： 高K栅介质 负偏置-温度不稳定性(NBTI) 反应-扩散(R-D)模型