On the current delivery limit of semiconducting carbon nanotubes

The current carrying capacity of single-walled semiconducting carbon nanotubes (CNTs) is studied by self-consistent quantum simulations using the non-equilibrium Green’s function formalism with the self-consistent Born approximation. The simulation shows that the current carrying capacity depends on the bias regime and is drastically different from that of metallic tubes. For long CNTs (with a length much longer than zone boundary and optical phonon scattering mean free path), the current saturates around 20 μA in the forward bias regime with unipolar transport due to phonon scattering. In ambipolar transport regime, the current delivery limit is still about 20 μA due to recombination of electron and hole currents. In contrast, for short semiconducting CNTs, the current delivery capacity can be above 25 μA in the unipolar transport regime and further double in the ambipolar transport regime. In reverse bias regime, the current of a long CNT can exceed 20 μA due to the second subband conduction and increased electron injection from the drain. The simulation provides a coherent explanation to the dependence of current delivery limit on bias regime and channel length, which is consistent with recent experiments.     

添加高效粘结剂的氧化锰矿粉冷固成团

以氧化锰矿粉为原料，添加ＺＢ粘结剂进行冷固成团，所得冷固团块不仅具有足够的机械强度，而且具有良好的耐湿性，适用于长距离运输和露天堆存，是一种可与块矿性能相媲美的优质炉料，为充分利用矿山及冶炼厂的锰矿粉找到了一条良好的途径．     

重油纳米化助燃效果研究与表征

将复配的分散剂加入重油中制备得到重油纳米颗粒，采用氧弹热值对比法对所研制的纳米化重油进行实验室评价。研究结果表明，纳米化后的重油燃烧性能得到了改善，在掺水量为3％～12％时，重油的燃烧效率提高了2．5％～6．1％。通过TEM观察，纳米化后的重油呈水包油（O／W）型乳液结构，油水界面清晰，界面膜较厚，乳化油粒径约为20～50nm，油水分散均匀，并且分散后的重油粘度增幅小，掺水量在15％以内，粘度增幅不超过20％，并且随着掺水量的增加，乳化重油的粘度逐渐减少。另外，乳化重油稳定性好，室温下至少可保存6个月，在80℃下存放3天未发生破乳现象。     

New concept of surface modification to LiCoO2

As the continuance of our series study on LiCoO₂ surface modification, the complicated traditional surface coating method is replaced with simple addition of amorphous YPO₄ and Al₂O₃ in commercial LiCoO₂ or in commercial electrolyte based on our understanding to the improvement mechanism of surface modification. Comprehensive studies by X-ray photoelectron spectroscopy (XPS), gas chromatography and mass spectroscopy (GC–MS), inductively coupled plasma (ICP) and Fourier transformed infrared (FTIR) indicate that the products of spontaneous reaction between the additive and the LiPF₆ based electrolyte are responsible for the performance improvements.     

Pad effects on material-removal rate in chemical-mechanical planarization

The role of a porous pad in controlling material-removal rate (MRR) during the chemical-mechanical planarization (CMP) process has been studied numerically. The numerical results are used to develop a phenomenological model that correlates the forces on each individual abrasive particle to the applied nominal pressure. The model provides a physical explanation for the experimentally observed domains of pressure-dependent MRR, where the pad deformation controls the load sharing between active-abrasive particles and direct pad-wafer contact. The predicted correlations between MRR and slurry characteristics, i.e., particle size and concentration, are in agreement with experimentally measured trends reported by Ouma¹ and Izumitani.²     

Investigation of amorphous Ni0.60Nb0.40 diffusion barriers

Interactions of Ni_0.60Nb_0.40 amorphous alloys with polycrystalline overlayers of gold and copper and single-crystal substrates of silicon. GaAs and GaP were observed with Auger depth profiling. The Ni-Nb layer was deposited by r.f. sputtering and was approximately 5000 Å thick. The overlayers were evaporated to a thickness of 1000 Å. The amorphous metal reacted with the gold overlayers and the GaAs and GaP substrates at temperatures well below the nominal crystallization temperature of 650 °C. The Cu/Ni-Nb/Si system, in contrast, was stable at 600 °C for at least 1 h. Samples were also measured that had been contaminated with approximately 5–10 at.% O. Complete separation of the niobium and nickel into distinct layers was seen. For the samples on silicon substrates this separation was accompanied by the formation of a nickel silicide layer.     

建立军用Foundry的探索

本文从ASIC的基本特点出发,阐述了建立ASIC标准加工线(Foundry)的重要性;国内集成电路产业已经具备建立Foundry的基础,建立有中国特色的Foundry是可以有所作为的。文章介绍了作者在建立军用Foundry方面的探索和初步成果。     

活动式水冷撇渣器的设计及应用

活动式水冷撇渣器是根据高炉冷却壁的工作原理设计的。第一台活动式水冷撇渣器于１９９３年２月２７日在安钢４号高炉投入运行，使用寿命长达１７个月零１８天，通铁量达到４０万ｔ。这种活动式水冷撇渣器具有投产少，收益高，维修方便，安全可靠等优点。