双束共蒸发制备Fe—Cu包埋团簇

基于气体聚集形成团簇的过程，利用双束蒸发共沉积方法，在室温下成功地制备了Ｆｅ－Ｃｕ纳米磁性包埋团簇样品，对样品的ＴＥＭ／ＥＤ分析表明，平均直径为２０ｎｍ左右的Ｆｅ团族被Ｃｕ原子所包裹，形成了以Ｆｅ团簇为芯，Ｃｕ原子为壳的良好的芯－壳式包埋结构。     

QBe2合金硬态分级时效电镜观察

ＱＢｅ２合金硬态分级时效电镜观察蔡传荣，张　琼，平德海，李斗星（福州大学，福州３５０００２）（中国科学院金属研究所固体原子像开放实验室）本工作在ＪＥＯＬ－２０００ＥＸ和ＪＥＯＬ－２０００ＦＸ上利用ＴＥＭ和ＨＲＴＥ技术，对硬态分级时效ＱＢｅ２合金［Ｃｕ...     

Si晶体中Cu和Fe杂质在Frank型位错上的不同沉淀行为

本文运用电子束感应电流技术和透射电子显微镜研究了直拉Ｓｉ单晶中Ｃｕ和Ｆｅ杂质在Ｆｒａｎｋ型位错上的沉淀行为．发现尽管在Ｓｉ中Ｃｕ杂质浓度远高于Ｆｅ杂质，但Ｃｕ杂质不沉淀在Ｆｒａｎｋ型位错上，而Ｆｅ杂质会沾污Ｆｒａｎｋ型位错．研究结果表明，样品中微小Ｐｕｎｃｈｅｄ－ｏｕｔ位错的存在和Ｃｕ杂质在Ｓｉ中的重复成核机制是Ｃｕ杂质不沉淀在Ｆｒａｎｋ型位错上的主要原因．     

Cu-Co合金的微结构与磁性的关系

利用场离子显微镜－原子探针（ＦＩＭ－ＡＰ）以及分析电镜（ＴＥＭ）研究甩带Ｃｕ８８Ｃｏ１２颗粒合金的微结构。ＦＩＭ的研究结果表明，原始状态下甩带Ｃｕ８８Ｃｏ１２合金中观察不到Ｃｏ的析出，可以看到明显的环结构，这说明甩带样品已很好地晶化。用ＡＰ进行纳米范...     

激光烧蚀等离子体与氮离子束反应生成CnN-m的质谱研究

采用飞行时间（ＴＯＦ）质谱（ＭＳ）方法,研究脉冲ＹＡＧ激光烧蚀石墨产生的碳团簇与氮原子离子束的空间反应,发现了一系列ＣｎＮ－ｍ团簇产物。对碳氮复合团簇负离子在空间形成的机理进行了分析。     

ZnCdSe—ZnSe／CaF2多量子阱中的三阶非线性

我们首次利用Ｚ－扫描技术在室温下研究了ＺｎＣｄＳｅ－ＺｎＳｅ／ＣａＦ２多量子了进中的三阶非线性，得到非线性系数ｎ２为－４．４６×１０＾－８ｅｓｕ。其主要非线性机理归结为ＺｎＣｄＳｅ－ＺｎＳｅ／ＣａＦ２多量子阱中的带填充效应。     

退火条件对β—FeSi_2形成的影响

本文采用反应沉积－团相外延法制备β－ＦｅＳｉ２溥膜．不同温度及持续时间的后退火处理的Ｘ射线衍射分析表明降低衬底温度，延长退火时间可以提高样品晶体质量．利用卢瑟福背散射方法研究了β－ＦｅＳｉ２的形成过程中的Ｓｉ的扩散。探讨了退火形成β－ＦｅＳｉ２的形成机制．     

微机图像处理系统和SEM对a—Fe2O3粉末的粒度分析

掺Ｓｎ的ａ－Ｆｅ２Ｏ３的粒度大小与它对ＣＯ的灵敏度密切相关，我们利用ＳＥＭ和计算机图像处理系统对它进行粒度分析，并讨论了作电镜粒度分析的样品制备方法和计算机图像分析的步骤，分析结果为得到理想粒度的ａ－Ｆｅ２Ｏ３的气敏材料提供了帮助。     

NEC研究先进的Al─ Ge─ Cu工艺

ＮＥＣ研究先进的Ａｌ┐Ｇｅ┐Ｃｕ工艺据ＳｅｍｉｃｏｎｄＩｎｔｌ１９９６年第６期报道：ＮＥＣ公司的研究人员正在不断观察Ｇｅ加入Ａｌ－Ｃｕ互连后的作用，以得到一种有实际生产价值的低温回流溅射工艺。这种使用低温回流溅射和化学机械抛光金属平坦化的Ａｌ－Ｇｅ...     

CdSe纳米团簇的透射电镜研究

在沸石分子筛中组装ＣｄＳｅ而形成半导体纳米团簇材料，并将组装ＣｄＳｅ后的沸石微粉制成完整的透射电镜薄膜，结合能谱测试，在透射电镜下观察所制得的材料的微观结构和形貌．结果表明在沸石中形成了尺寸单一、分布均匀的团簇材料     

FeCuNbCrSiB薄膜的制备及其巨磁阻抗效应研究

采用磁控溅射方法,在玻璃基片上制备了非晶的Fe73.5Cu1Nb3Cr0.5Si13B9薄膜及三明治结构M/C/M(M为Fe73.5Cu1Nb3Cr0.5Si13B9;C为Cu)的多层膜。在频率(1~40)MHz下,研究了薄膜材料的巨磁阻抗(GMI)效应随外加磁场的变化关系。结果表明:单层膜的GMI效应较小,只有4.4%;而三明治结构多层膜的GMI效应,比单层膜有较大幅度的提高,在5MHz、120Oe下,纵向和横向GMI效应分别达–17.4%和–20.7%。薄膜材料的纵向GMI效应随外加磁场变化呈现先增后减,而横向GMI效应随外加磁场的增加而单调递减,其变化规律与薄膜的易轴取向有很大关系。     

Modification of the electron spectrum and vibrational properties of amorphous carbon by copper doping

The near-gap electron spectrum and the effective charge distribution in graphite-like carbon nanoclusters of simple geometry in a-C: H containing a single Cu atom are calculated in the tight-binding approximation. Only the coupling between π electrons of the constituent C atoms and one valence s electron of the Cu atom is taken into account. The binding energy of the Cu atom in the clusters and the static dipole moment of the clusters are calculated. The results are invoked to interpret the experimentally observed activation of the Raman G band in the IR spectrum of a-C: H: Cu as a consequence of a lowering of the symmetry of the graphite-like clusters due to copper intercalation. Experimental data on the time dependence of the G band intensity during isothermal annealing of a-C: H: Cu are presented. The data suggest the possibility of reversible transfer of Cu atoms between the impurity states in the copper-carbon clusters and the impurity states in the purely copper clusters. The average activation energies of direct and reverse transfer are estimated from the experiment. Fiz. Tekh. Poluprovodn. 32, 931–938 (August 1998)     

Distribution of Elements in a Cu-Added FeSi<Subscript>2</Subscript> Alloy Under Peritectoid and Eutectoid Reactions

The distribution of Si, Fe, and Cu in FeSi₂ alloys, with or without the addition of Cu, were studied by electron probe microanalysis (EPMA). Alloys were prepared by slow solidification from the melt. Without Cu addition, both ε- and α-phases were clearly observed, and a β-phase surrounding the ε-phase was additionally observed after in situ annealing at 950°C for 12 h. With inclusion of 0.5 at.% Cu, the eutectoid reaction (α → β + Si) was enhanced greatly. Only 0.01 at.% Cu was dissolved into the ε-phase, with the excess Cu atoms being largely found at the outer edge of the ε-phase. Ex situ annealing at 950°C for 12 h greatly changed the distribution of Si, Fe, and Cu. The ε-phase changed its Si/Fe atomic ratio from 1.470 to 1.907, indicating an early stage of the peritectoid reaction (ε + α → β) and/or the subsequent reaction (ε + Si → β), with an increase in the Cu content up to 0.04 at.%. The size of this new phase was smaller than the original ε-phase, and this new phase was surrounded by a shell of Si/Fe with an atomic ratio of 0.727 to 1.788 and a Cu content of 0.01 at.% to 0.11 at.%. In situ annealing under the same condition yielded different results: a large amount of Si segregates from the α-phase matrix, leaving a Si/Fe atomic ratio of only 0.506 to 0.530. The peritectoid reaction of the ε-phase was found to depend on the Cu content. For the ε-phase with undetectable levels of Cu, the Si/Fe atomic ratio remained at 0.954 to 0.998, but this ratio decreased with increasing Cu content to 0.55 at 2.20 at.% Cu. A plot of at.% Cu versus Si/Fe atomic ratio revealed a local minimum at the ε-phase and expectedly at both the β- and α-phases. Nonstoichiometric structures (neither α-, β- nor ε-phases) seemed to have higher at.% Cu compared with those with the closest Si/Fe composition.     

Fe_(81)Zr_7Nb_2B_(10)和Fe_(78)Co_(2.5)Zr_7Nb_2B_(10)Cu_(0.5)合金的热性能、微观结构及磁性能研究

采用单辊快淬法制备了Fe81Zr7Nb2B10和Fe78Co2.5Zr7Nb2B10Cu0.5非晶合金,在不同温度下对两种合金进行了热处理。利用差热分析仪(DTA)、X射线衍射仪(XRD)和振动样品磁强计(VSM)等仪器对两种合金的热性能、微观结构和磁性能进行了测试分析。结果表明在Fe78Co2.5Zr7Nb2B10Cu0.5合金的晶化过程中存在预结晶效应,而在Fe81Zr7Nb2B10合金的晶化过程中没有。Fe81Zr7Nb2B10和Fe78Co2.5Zr7Nb2B10Cu0.5合金经803 K退火后,分别有α-Fe和α-Fe(Co)相从非晶基体中析出。随退火温度的升高,两种合金的比饱和磁化强度(Ms)变化趋势相似,但矫顽力(Hc)变化趋势明显不同。     

双掺杂和三掺杂铌酸锂晶体稳定全息存储的实验研究

对两种不同氧化 还原处理下的四种不同掺杂Cu∶Ce ,Mn∶Cu∶Ce ,Mn∶Fe和Mn∶Fe∶Mg的铌酸锂晶体进行了红光和紫光光色效应稳定全息存储的实验研究 ,实现了LiNbO3∶Cu∶Ce和LiNbO3∶Mn∶Cu∶Ce晶体中的稳定全息存储。实验结果表明只有高氧化的晶体才能实现稳定全息存储。在高信噪比前提下 ,LiNbO3∶Cu∶Ce晶体稳定衍射效率最高。     

Photoluminescence Analysis of Iron Contamination Effect in Multicrystalline Silicon Wafers for Solar Cells

We investigated the effect of Fe contamination on the electronic properties of dislocation clusters in relation to oxygen precipitation in multicrystalline silicon (mc-Si). Photoluminescence (PL) spectroscopy and mapping were performed at room and liquid-He temperatures on mc-Si wafers before and after Fe contamination. PL spectra consisted of the band-edge emission, the 0.78-eV emission associated with oxygen precipitates, and the dislocation-related D-lines. The Fe contamination increased the electrically active dislocation clusters. Part of these clusters acted as preferential oxygen precipitation sites, and their electronic properties were not further influenced by the Fe contamination.     

A study of deep levels in GaAs by capacitance spectroscopy

We show how the DLTS capacitance spectroscopy technique can be used to detect small amounts of deep level impurities in GaAs p-n junctions. The DLTS spectra associated with Cu, Fe, Cr, 0, and two unidentified but commonly occurring deep levels in GaAs are shown. The LPE distribution coefficients are obtained for Cu, Fe, and Cr. The carrier capture cross sections for six levels are measured and give evidence for capture by multiphonon emission.     

基于特征聚类对群三元组损失的车辆再识别

车辆再识别旨在从多个摄像机拍摄的图像中识别出同一车辆.本文提出了一种对群三元组损失函数,以特征中心点替代均值,并将对群思想和三元组损失相结合,优化了困难样本的识别.车辆再识别过程中,对群损失函数的训练过程扩大了样本规模,增加了计算量,且传统对群损失函数无法准确处理困难正样本.为此,提出了一种特征聚类对群三元组损失函数.本方法采用正样本特征聚类中心并改进了三元组损失函数的设计,从而优化了对群损失函数.在不扩增输入样本数量的同时提升了算法处理困难样本的能力.实验表明,与主流车辆再识别算法相比,本方法可有效提升车辆再识别的准确率.     

添加剂对Fe—Cu系陶瓷材料负阻特性的影响

文章介绍了以Ｆｅ２Ｏ３和Ｃｕ２Ｏ为主成分的陶瓷材料的负阻特性，分析论述了Ｃｏ２Ｏ３、Ｂｉ２Ｏ３以及ＭｎＯ２掺杂对Ｆｅ－Ｃｕ系陶瓷材料负阻性能的影响，实验制得负阻系数ｎ＞１０，电压Ｖｐ＞２００的负阻性能良好的陶瓷材料。     

Ni80Fe20/Cu基磁性多层膜和自旋阀的微结构

用高分辨电子显微学及平行电子能量损失谱方法研究了Ni80Fe20/Cu基磁性多层膜和自旋阀的显微结构.高分辨像显示,磁性多层膜及自旋阀均具有沿薄膜生长方向的柱晶结构.Ni,Fe,Cu和Mn元素的成分分布图显示,柱晶内仍保持完整的层状结构.沿薄膜生长方向的自旋阀元素分布曲线分析表明,NiFe层中的Ni元素沿柱晶晶界向相邻Cu层扩散.讨论了这些低维磁电子学材料的显微结构对磁输运性能的影响.