介孔碳材料对蛋白质的吸附行为

用紫外分光光度法,找出介孔碳材料对蛋白质的最佳吸附条件,并测定出该介孔碳材料对溶菌酶的最大吸附量。主要从3方面研究介孔碳材料对蛋白质吸附行为的影响。分别是介孔碳材料对蛋白质吸附行为随接触时间的变化产生的影响,pH值的改变对介孔碳材料吸附蛋白质行为的影响,以及介孔碳材料的量的改变对蛋白质吸附行为随接触时间的变化产生的影响。结果表明,当溶菌酶溶液的初始浓度为210μm ol/L,pH值为11.0,接触时间为96h时介孔碳材料对蛋白质即可达到吸附饱和。该介孔碳材料在最佳条件下对溶菌酶的最大吸附量为27.32μm ol/g,表现出优越的溶菌酶吸附性能。     

Electrochemical properties of Mn-doped activated carbon aerogel as electrode material for supercapacitor

Carbon aerogel (CA) was prepared by a sol-gel polymerization of resorcinol and formaldehyde, and it was activated with KOH to obtain activated carbon aerogel (ACA). Specific capacitance of carbon aerogel and activated carbon aerogel was measured by cyclic voltammetry and galvanostatic charge/discharge methods in 6 M KOH electrolyte. Activated carbon aerogel showed higher specific capacitance than carbon aerogel (136 F/g vs. 90 F/g). In order to combine excellent electrochemical performance of activated carbon aerogel with pseudocapacitive property of manganese oxide, 7 wt% manganese oxide was doped on activated carbon aerogel by an incipient wetness impregnation method. For comparison, 7 wt% manganese oxide was also doped on carbon aerogel by an incipient wetness impregnation method. It was revealed that 7 wt% Mn-doped activated carbon aerogel (Mn/ACA) showed higher specific capacitance than 7 wt% Mn-doped carbon aerogel (Mn/CA) (168 F/g vs. 98 F/g). The enhanced capacitance of 7 wt% Mn-doped activated carbon aerogel was attributed to the outstanding electric properties of activated carbon aerogel as well as the faradaic redox reactions of manganese oxide.     

用RAMAN光谱研究碳纤维皮芯结构随热处理温度的演变规律

用Raman光谱研究碳纤维经不同温度热处理后其皮芯结构的演变规律。结果发现：随着热处理温度的提高,碳纤维表面和内部的Raman光谱具有相似的变化趋势。同时,表征碳纤维表面和内部石墨化程度的R_s与 R_c值均越来越小,且R_s值减小得更快,说明碳纤维的石墨化程度越来越高,并且表面的石墨化程度提高的更快,这是因为碳纤维表面和内部的碳有着不同的石墨化物性。前者接近于软碳,易于石墨化;后者接 近于硬碳,难于石墨化,可能是树脂碳。文章提出并采用皮芯结构因子R_sc(＝R_s/R_c)来表征了碳纤维的皮芯结构程度。当R_sc等于1时,碳纤维是完全均质的。随着热处理温度的升 高,碳纤维的R_sc趋向于零,说明其皮芯结构越来越严重。碳纤维的皮芯结构加重是最终导致其抗拉强度不断降低的原因之一。     

Sonochemical preparation of carbon nanosheet from carbon black

Preparation of carbon nanosheet via ultrasound irradiation of carbon black under ambient conditions was reported for the first time. The structure of resulting carbon nanosheet was characterized by TEM, HRTEM, EDX and AFM. The experimental results showed that the carbon nanosheet is composed of ordered graphite carbon layers with a thickness of several nanometers.     

Synthesis and characterization of carbon nanotubes on carbon microfibers by floating catalyst method

In this paper, carbon nanotubes were synthesized on carbon microfibers by floating catalyst method with the pretreatment of carbon microfibers at the temperature of 1023 K, using C₂H₂ as carbon source and N₂ as carrier gas. The morphology and microstructure of carbon nanotubes were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The composition of carbon nanotubes was determined by energy dispersive X-ray spectroscopy (EDX). The results showed that the surface of treated carbon microfibers was thickly covered by carbon nanotubes with diameters of about 50 nm. EDX image indicated that the composition of carbon nanotubes was carbon. In comparison with the sample grown on untreated carbon microfibers surface, it was found that after carbon microfibers were boiled in the solution of sulfur acid and nitric acid (VH₂SO₄:VHNO₃ = 1:3) and immersed in the solution of iron nitrate and xylene, carbon nanotubes with uniform density can be grown on carbon microfibers surface. Based on the results, we concluded that the pretreatment of carbon microfibers had great effect on the growth of carbon nanotubes by floating catalyst method.     

In situ ellipsometry study of atomic hydrogen etching of extreme ultraviolet induced carbon layers

Atomic hydrogen based etching is generally considered an efficient method for the removal of carbon films resulting from photo-induced hydrocarbon dissociation, as occurs in extreme ultraviolet (EUV) photolithography environments. The etch rate of atomic hydrogen for three different kinds of carbon films was determined, namely for EUV-induced carbon, hot filament evaporated carbon and e-beam evaporated carbon. The etching process was monitored in situ by spectroscopic ellipsometry. The etch rate was found to depend on the type of carbon (polymer or graphite-like), on the layer thickness, and on the temperature. The EUV-induced carbon shows the highest etch rate, with a value of ∼0.2 nm/min at a sample temperature of 60 °C. The more graphite-like carbon layers showed an etch rate that was about 10 times lower at this temperature. An activation energy of 0.45 eV was found for etching of the EUV-induced carbon layer.     

Carbon Modified Silica based Adsorbent for Potential Application

The carbon modified silica adsorbents were prepared by synthesizing and modifying zeolite Y type with activated carbon. This paper reports on effects of activated carbon loadings on the methane and nitrogen adsorption, structure and properties of carbon modified zeolite Y. With the increase in activated carbon loadings, the surface area, pore size and pore volume of the activated carbon loaded zeolite Y adsorbent decreased. The intensity of the diffraction patterns of zeolite Y decreased after the activated carbon was loaded. With increasing activated carbon loadings, the intensity of diffraction peaks decreased. Adsorption capacity of nitrogen (N₂) was smaller than adsorption capacity of methane (CH₄) by using activated carbon modified silica. When activated carbon loadings 30% wt.%, adsorption capacity of methane and nitrogen was 12.9317 wt.% and 12.6115 wt.%, these were caused by difference in molecular weight. The molecular weight of nitrogen is bigger than molecular weight of methane.     

Nano structure of low crystallinity carbon materials analyzed by using high energy X-ray diffraction

In this study, we tried to characterize a kind of low crystallinity carbon materials. The structure of polyparaphenylene(PPP)-based carbon was analyzed by means of high energy X-ray diffraction using the apparatus of SPring-8. The experimental results revealed the existence of basic structural units (BSU) in the highly disordered materials like PPP-based carbon. It is thought that the PPP-based carbons consist of small turbostratic particles, which have a few piled up poly-aromatic layers. The structure of the PPP-based carbon which seemed to be amorphous was estimated to have hexagonal carbon layers with the size of up to 1 nm. The pores in the PPP-based carbon seem to be clearances formed among the BSUs and amorphous carbon. The pore size of PPP-based carbon was estimated from the result of N₂ absorption measurement. The experimental results suggested that the lithium ion charge mechanism in the PPP-based carbon differs from that in graphite.      

Activated carbon aerogel as electrode material for coin-type EDLC cell in organic electrolyte

Carbon aerogel (CA) was prepared by a carbonization of resorcinol–formaldehyde (RF) polymer gels, and it was chemically activated with KOH to obtain activated carbon aerogel (ACA) for electrode material for EDLC in organic electrolyte. Coin-type EDLC cells with two symmetrical carbon electrode were assembled using the prepared carbon materials. Electrochemical performance of the carbon electrodes was measured by galvanostatic charge/discharge and cyclic voltammetry methods. Activated carbon aerogel (20.9 F/g) showed much higher specific capacitance than carbon aerogel (7.9 F/g) and commercial activated carbon (8.5 F/g) at a scan rate of 100 mV/s. This indicates that chemical activation with KOH served as an efficient method to improve electrochemical performance of carbon aerogel for EDLC electrode in organic electrolyte. The enhanced electrochemical performance of activated carbon aerogel was attributed to the high effective surface area and the well-developed pore structure with appropriate pore size obtained from activation with KOH.     

基于硬度回归法测定退火碳钢的含碳量

测量了已知退火碳钢的硬度,揭示了含碳量与硬度线性相关的特性.利用最小二乘法进行回归分析,得到硬度与含碳量的线性方程,并以此实现对未知碳钢的估计.另通过金相组织观察法和杠杆定律再次对未知碳钢含碳量进行估计,结果发现与硬度测量法估计的含碳量基本一致.比较两种方法,硬度测量法更客观,更准确.并与标准金相图谱比对,进一步验证了实验结论.     

多壁碳纳米管对p型Ba0.3FeCo3Sb12化合物热电性能的影响

用两步固相反应法合成了P型Ba填充方钴矿化合物Ba0.3FeCo3Sb12，并采用放电等离子烧结法(SPS)制备了Ba0.3FeCo3Sb12／多壁碳纳米管复合材料．研究了Ba0.3FeCo3Sb12／多壁碳纳米管复合材料的结构及多壁碳纳米管对其热电性能的影响规律：SEM分析表明多壁碳纳米管比较均匀地分布在Ba0.3FeCo3Sb12基体中；随着碳纳米管添加量的增加，Ba0.3FeCo3Sb12／多壁碳纳米管复合材料的电导率下降、塞贝克系数略微下降、晶格热导率大幅度降低，当碳纳米管含量为5％时其晶格热导率最小；当碳纳米管的含量为3％时，本研究得到的Ba0.3FeCo3Sb12／碳纳米管复合材料的最大ZT值达0．78．     

Microstructural investigations of zirconium oxide—on core–shell structure of carbon nanotubes

Single-walled carbon nanotubes and multi-walled carbon nanotubes/ZrO₂ nanocomposites were obtained by isothermal hydrolyzing and chemical precipitation method for both the carbon nanotubes. The coating was taken place by dispersion of both the carbon nanotubes in ZrOCl₂·8H₂O aqueous solution. However, a highly conformal and uniform monoclinic zirconia coating was deposited on multi-walled carbon nanotubes rather than single-walled carbon nanotubes by this new and simple method. Also, it has been observed that the thickness of the individual carbon nanotube after zirconia coating was increased by isothermal hydrolyzing process rather than traditional chemical precipitation method and it has been confirmed by high-resolution transmission electron microscopy study.     

Study on structure change of carbon nanotubes depending on different reaction gases

Aligned carbon nanotubes were grown by plasma-enhanced hot filament chemical vapor deposition using different reaction gases and they were investigated by scanning electron microscopy and transmission electron microscopy. It is found that the hollow carbon nanotubes were formed using methane and hydrogen as the reaction gases, but the bamboo-structured carbon nanotubes were grown when ammonia was added into the reaction gases, indicating that the structure of the aligned carbon nanotubes was changed depending on different reaction gases. On setting of diffusion of carbon, the effects of the nitrogenous gas on the structure change of carbon nanotubes are studied.     

Preparation of carbon nanosheets deposited on carbon nanotubes by microwave plasma-enhanced chemical vapor deposition method

Carbon nanosheets were synthesized by microwave plasma-enhanced chemical vapor deposition method on carbon nanotubes substrate which was treated by hydrogen plasma. The results showed that the diameters of carbon nanotubes first got thick and then “petal-like” carbon nanosheets were grown on the outer wall of carbon nanotubes. The diameters of carbon nanotubes without and with carbon nanosheets were 100-150 and 300-500 nm, respectively. Raman spectrum indicated the graphite structure of carbon nanotubes/carbon nanosheets. The hydrogen plasma treatment and reaction time greatly affected the growth and density of carbon nanosheets. Based on above results, carbon nanosheets/carbon nanotubes probably have important applications as cold cathode materials and electrode materials.     

The effects of carbon nanotube addition and oxyfluorination on the glucose-sensing capabilities of glucose oxidase-coated carbon fiber electrodes

Glucose-sensing electrodes were constructed from carbon fibers by electrospinning and heat treatment. By controlling the pore size, the specific surface area and pore volume of the electrospun carbon fibers were increased for efficient immobilization of the glucose oxidase. Carbon nanotubes were embedded as an electrically conductive additive to improve the electrical property of the porous carbon fibers. In addition, the surface of the porous carbon fibers was modified with hydrophilic functional groups by direct oxyfluorination to increase the affinity between the hydrophobic carbon surface and the hydrophilic glucose oxidase molecules. The porosity of the carbon fibers was improved significantly with approximately 28- and 35-fold increases in the specific surface area and pore volume, respectively. The number of chemical bonds between carbon and oxygen were increased with higher oxygen content during oxyfluorination based on the X-ray photoelectron spectroscopy results. Glucose sensing was carried out by current voltagram and amperometric methods. A high-performance glucose sensor was obtained with high sensitivity and rapid response time as a result of carbon nanotube addition, physical activation and surface modification. The mechanism of the highly sensitive prepared glucose sensor was modeled by an enzyme kinetics study using the Michaelis-Menten equation.     

非晶碳氮纳米尖端的微结构和发光机理

利用等离子体增强热丝化学气相沉积系统,用CH₄、H₂和N₂为反应气体,在Si衬底上制备了碳氮纳米尖端。用扫描电子显微镜和显微Raman光谱仪对其进行了表征。在室温下测试了它的发光性能,发光谱由中心约为406 nm和506 nm的两条发光带组成。根据Raman散射谱,对其微结构进行了分析。结合非晶碳氮薄膜的结构和发光机理,分析了它的发光性能。     

碳纳米管/丙烯酸酯涂料的制备及其红外吸波性能

"利用表面改性剂对碳纳米管进行表面改性来防止其颗粒的团聚,从而制得分散性较好的碳纳米管浆料,在此基础上来制备碳纳米管/丙烯酸酯涂料,并研究了它在近红外波段的反射率．分析了PVC浓度、表面改性剂的种类及浓度以及碳纳米管的管长,对碳纳米管/丙烯酸酯涂料在?=930 nm处反射率的影响,并对涂料工艺进行了优化设计,最终制备出了吸收性能优良的碳纳米管/丙烯酸酯涂料．它在840~950 nm的近红外波段的反射率为均在0.1%以下并且透射率均在1.0%以下．"     

碳纳米管辐射太赫兹波的理论分析与数值验证

基于简单紧束缚方法理论,利用一维碳纳米管的量子化周期边界条件得到了碳纳米管的电子能级结构关系.并结合已报道的碳纳米管中电子与声子相互作用的实验结果,得到了碳纳米管能够辐射太赫兹波的结论.通过数值结果验证了碳纳米管在外场作用下能够产生太赫兹波,并对数值计算结果中太赫兹波的振荡现象给予合理的解释.其结果为进行碳纳米管产生太赫兹辐射的实验研究提供深入的理论基础. 关键词： 太赫兹波 碳纳米管     

Effects of carbon content on the electrochemical properties of spherical pyrrhotine/carbon nanocomposites

Spherical pyrrhotine/carbon nanocomposites with different carbon contents were synthesized by a solvothermal method followed by heat treatment. The carbon content of the nanocomposites was controlled by changing the amount of the carbon precursor. The samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM); the influence of carbon layer thickness on the electrochemical performance was analyzed by charge/discharge cycling and X-ray photoelectron spectroscopy (XPS). Results show that the moderate carbon layer displays a positive effect in improving reversible capacity and the rate capability. The optimal carbon content in the pyrrhotine/carbon nanocomposites was about 15 wt.%, which can retain a high reversible capacity of 689.5 mAh/g even after 50 cycles at 0.1 C and an excellent rate capability of 393.4 mAh/g at 5 C. The synthesized nanocomposites show a promising potential as a novel anode material for lithium-ion batteries.     

Effect of carbon nanotubes on the anode performance of natural graphite for lithium ion batteries

A comparative investigation was carried out on carbon black and multiwalled carbon nanotubes as conductive additives in spherical natural graphite for lithium ion batteries. Scanning electron microscopy images showed that carbon nanotubes interlaced graphite particles in series to form a three-dimensional network. The constant current charge-discharge experiments showed that carbon nanotubes were more effective in improving reversible capacity and cycle stability. The reversible capacity was improved to 366 mAh/g and the cycle stability was improved effectively when carbon nanotubes were used. The research is of potential interest to the application of carbon nanotubes as conductive additives in anode materials for high-power lithium ion batteries.