在等离子体中纤维素的接枝共聚

脱胶苎麻纤维和粘胶人造短纤维吸附了丙烯酰胺单体后曝露在低温等离子体中,纤维素与丙烯酰胺发生轻度接枝共聚反应。脱胶苎麻纤维样品在功率40—160W,曝露时间5—40分钟,反应器内压力0.5Torr的处理条件下,接枝率均很低,不超过10％。如将反应器内压力升高到0.7Torr,功率又维持在140W时,接枝率虽可提高到20％左右,但制成品已刻蚀损伤严重,纤维发黄变脆。用结构不同的粘胶纤维与之对比,发觉在相同处理条件下,接枝效率较苎麻高些,表现出结构因素在等离子体引发反应中亦能发生影响的迹象,接枝产品的吸湿性能与染色性能均有所提高。     

判别常数项级数敛散性的几个常见错误

一、判一般项级数敛散性乱用正项级数审敛法 例1 判定     

Highly conductive and transparent carbon nanotube-based electrodes for ultrathin and stretchable organic solar cells

In this work, we have presented a freestanding and flexible CNT-based film with sheet resistance of 60 ?/ and transmittance of 82% treated by nitric acid and chloroauric acid in sequence. Based on modified CNT film as a transparent electrode, we have demonstrated an ultrathin, flexible organic solar cell(OSC) fabricated on 2.5-μm PET substrate. The efficiency of OSC, combined with a composite film of poly(3-hexylthiophene)(P3HT) and phenyl-C61 butyric acid methyl ester(PCBM) as an active layer and with a thin layer of methanol soluble biuret inserted between the photoactive layer and the cathode, can be up to 2.74% which is approximate to that of the reference solar cell fabricated with ITO-coated glass(2.93%). Incorporating the as-fabricated ITO-free OSC with pre-stretched elastomer, 50% compressive deformation can apply to the solar cells. The results show that the as-prepared CNT-based hybrid film with outstanding electrical and optical properties could serve as a promising transparent electrode for low cost, flexible and stretchable OSCs, which will broaden the applications of OSC and generate more solar power than it now does.     

铁催化薄膜的微观结构对碳纳米管阵列生长的影响

本文利用热化学气相沉积法（TCVD）,系统地研究了NH3预处理对硅基底上沉积的催化剂铁膜的结构及所制备的碳纳米管形态的影响。研究结果表明,利用氨气对硅基底上的催化剂铁膜进行适当的预处理不仅可以将催化剂颗粒细化,还可以使催化剂在碳纳米管的制备过程中保持较高的催化活性,促进分解出的活性碳原子在催化剂中扩散和析出,增强碳纳米管的成核和生长,从而合成出纯度较高、定向性好的碳纳米管阵列。     

Performance improvement of continuous carbon nanotube fibers by acid treatment

Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images and Raman spectra,the acid treatment results in the compaction and surface modification of the CNTs in fibers,which are beneficial for the electron and load transfer.Compared to the HNO3 treatment,HClSO_3 or H_2SO_4 treatment is more effective for the improvement of the fibers' properties.After HCISO_3 treatment for 2 h,the fibers' strength and electrical conductivity reach up to-2 GPa and-4.3 MS/m,which are promoted by-200%and almost one order of magnitude than those without acid treatment,respectively.The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G' band and the strain transfer factor of the fibers under tension.The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength.With the HCISO3 treatment,the strain transfer factor is enhanced from-3.9%to-53.6%.     

高温氨刻蚀对硅基纳米铁薄膜显微形态的影响

本文研究了750℃高温氨刻蚀对硅基铁纳米薄膜显微形态变化的影响。找到了纳米铁颗粒平均直径和平均分布密度随刻蚀时间、薄膜厚度等参数变化的规律,并对氨在其变化过程中的作用机制进行了初步探讨。研究发现:5~10nm的薄膜原始厚度和8~12m in的刻蚀时间是硅基铁纳米薄膜催化高定向碳纳米管阵列化学气相沉积生长的较理想条件。     

大直径半导体碳纳米管手性结构实现宏量分离

正从概念上讲,碳纳米管是由石墨烯卷曲形成的一维管状分子,它不仅具有石墨烯优异的力学、热学性能以及极高的载流子迁移率等特点,而且具有结构可调的能隙结构,表现出优异的电子以及光电子特性~([1]),是制备高速、低功耗、高集成度电子和光电子集成回路的理想材料。相对于传统的Si基半导体器件,碳纳米管电子器件的能效能够提高一个数量级以上,而且能够有效克     

Dependence of the solar cell performance on nanocarbon/Si heterojunctions

Solar cells that combine single-crystalline silicon(Si) with graphene(G) have been widely researched in order to develop next-generation photovoltaic devices. However, the power conversion efficiency(PCE) of G/Si solar cell without chemical doping is commonly low due to the relatively high resistance of graphene. In this work, through combining graphene with carbon nanotube(CNT) networks, we fabricated three kinds of hybrid nanocarbon film/Si heterojunction solar cells in order to increase the PCE of the graphene based Si solar cell. We investigated the characteristics of different nanocarbon film/Si solar cells and found that their performance depends on the heterojunctions. Specifically, a doping-free G-CNT/Si solar cell demonstrated a high PCE of 7.9%, which is nearly equal to the combined value of two individuals(G/Si and CNT/Si). This high efficiency is attributed to the synergistic effect of graphene and CNTs, and can be further increased to 9.1% after applying a PMMA antireflection coating. This study provides a potential way to further improve the Si based heterojunction solar cells.     

低温等离子体处理对苎麻纤维聚合度及失重的影响

<正> 一、前言一些研究工作表明纤维素纤维经过低温等离子处理后,纤维的聚合度、吸湿性、力学性能、以及某些结构(形态结构与聚集态结构)均发生一定的变化,而此种变化的程度与应用等离子的功率、处理的时间和处理的条件有关。可以设想,不同纤维素纤维,它们变化的趋势也会有所差异。由于在这方面的研究工作开始不久,研究     

碳纳米管阵列拉曼光谱的对比研究

利用热化学气相沉积技术制备碳纳米管阵列,并对不同工艺下获得的一系列定向碳纳米管阵列进行了拉曼光谱的对比研究。研究发现：碳纳米管阵列一阶拉曼光谱的G峰中心和D峰中心都会向低波数方向发生红移。并且阵列中碳管的一致性、准直性越好,红移的波数就越多。除了谱峰以外,D线和G线的积分强度比I_D / I_G也能够反映所研究的碳材料的有序度和完整性。I_D / I_G越低,说明该碳纳米管阵列的石墨化越好,无定形碳杂质越少。