共查询到20条相似文献,搜索用时 93 毫秒
1.
文中基于氢在椰壳活性炭YK-1上的平衡吸附数据,以探寻氢在碳基材料上适宜存储条件为目的,研究吸附氢分子间相互作用能随储存系统温度、压力、表面遮盖率的变化规律。首先,依据容积法的原理,在温度区间113K—293K、压力范围0—13MPa测试氢在YK-1椰壳活性炭上的吸附等温线。其次,应用格子理论推导通用吸附等温方程,通过等温方程的线性标绘确定氢分子在吸附表面的最大浓度,并由氢分子在活性炭典型吸附空间内受到的壁面作用势函数迭代求解氢分子受到的壁面作用势,进而获得与各吸附平衡态对应的氢分子间相互作用能。最后,根据氢分子间作用能随温度、表面遮盖率等的变化关系,分析氢分子在此活性炭上吸附的特点。 相似文献
2.
本文在Eikonal近似的框架下,用K±N散射分波相移和~(40-48)Ca的三参数Fermi型密度分布函数计算了K~±与~(40-48)Ca的弹性散射微分截面;在比较由各家提供的基本参数所得到的理论计算值与实验符合程度的基础上,通过调整中子分布函数的参数,改善了理论计算值与实验值的符合.结果表明,~(40)Ca的中子分布比较其质子的分布有较小的均方根半径(约小0.15fm)和较薄的表面厚度.这是与H.F.计算相容的,并与其他作者对中能质子与钙的弹性散射分析的结果相一致. 相似文献
3.
4.
5.
6.
基于集团模型电荷自洽的EHT(Extended Hückel Tneory)方法对K在石墨(0001)表面吸附态进行了优化计算.在3种不同的覆盖度(Θ)下,对k-石墨系统的电荷转移量△Q、吸附能△E、态密度PDOS和TDOS、Mulliken集居数和成键性质进行了比较.认同K/石墨吸附系统是石墨插层化合物(GIC)的雏型.并用LMTO方法对KC8完成电子结构的第一性原理研究,得到与EHT完全一致的结果:K4s-Ca杂化态主要位于低能区域远离费米能级,构成反键轨道其电子转移到费米能级附近K3d-Cπ成键的杂化轨道上.空的3d轨道在目前EHT方法和LMTO方法计算中扮演了关键角色.这与其他文献K-4s态处在EF能级的结果不同,但与早期Fischer(1984),Johnson(1986)XPS,ARUPS的实验结果吻合. 相似文献
7.
基于Dyson-Schwinger方程(DSEs)所确定的夸克传播子和算符成积展开(OPE),在彩虹近似下,预言了QCD真空中非定域夸克真空凝聚的结构。这种结构由夸克自能函数Af和Bf决定,通过数值求解DSEs就可以得到这些自能函数。但是,直接数值求解DSEs方程非常复杂,这里采用Roberts和Williams提出的参数化方法,用参数化的夸克传播函数σf v(p2)和σf s(p2)计算夸克自能函数。同时,也计算了定域的夸克真空凝聚值,夸克胶子混合的真空凝聚值,以及夸克的虚度。理论预言和计算结果均与标准QCD求和定则、格点QCD和瞬子模型的理论结果大致相符。和这些模型的结果相比,参数化方法得到的轻夸克(u,d,s)的定域真空凝聚偏大,这主要是由于模型依赖导致的。与u,d夸克相比,s夸克的真空凝聚比较大,这是因为s夸克自身质量较大的缘故。当然,Roberts-Williams参数化的夸克传播子只是一个经验公式,只能近似描述夸克的传播。 相似文献
8.
对ISR和SppS非弹过程赝快度分布的实验数据进行最佳参数拟合直至其最高能量S=900GeV,假定次级粒子多重数分布近似遵循KNO Scaling,横动量近似遵循指数分布,构造了一个适合于分析乳胶室实验结果的强子-强子核相互作用的参数化模型. 相似文献
9.
本文在Elikonal近似的框架下, 用K±N散射分波相移和40—48Ca的三参数Fermi型密度分布函数计算了K±与40—48Ca的弹性散射微分截面; 在比较由各家提供的基本参数所得到的理论计算值与实验符合程度的基础上, 通过调整中子分布函数的参数, 改善了理论计算值与实验值的符合. 结果表明, 40Ca的中子分布比较其质子的分布有较小的均方根半径(约小0.15fm)和较薄的表面厚度. 这是与H.F. 计算相容的, 并与其他作者对中能质子与钙的弹性散射分析的结果相一致. 相似文献
10.
采用计算机模拟方法研究不同温度下乙烷在不同孔径的MCM-41中的吸附.其中乙烷分子采用两个LJ中心的势模型表征,乙烷分子与MCM-41孔壁的相互作用采用一个连续的势模型表示.除考察了温度、孔径对吸附量的影响外,还研究这些量对乙烷分子在孔中的甲基和质心的分布,以及它们对乙烷分子在孔中的排列方向的影响.GCMC模拟结果发现,在180K和300K时壁面处都有较多的乙烷分子倾向于沿着壁面排列,同时在180K时其余的流体分子倾向于垂直于壁面排列,而在300K时其余的分子并不像在180K时一样倾向于垂直于壁面排列.模拟结果还表明,除壁面附近外,即使是在180K的较低温度下,乙烷分子的排列也是混乱和无序的. 相似文献
11.
A method of characterization of carbonaceous materials using nongraphitized carbon black as a reference is considered. The Tarazona density functional theory was applied to amorphous solids to describe nitrogen adsorption on nongraphitized carbon black. This allows us to describe energetic heterogeneity without the need to invoke any energy distribution functions. To derive the pore size distribution (PSD) of porous carbon whose pore walls are non-graphitized, we used the entropy concept in the regularization method. With this approach PSD is more well-behaved than that obtained with the usual means. We applied this new theory to study the effects of technological parameters on porous structure of a series of activated carbon. 相似文献
12.
Alaleh Vaghef Koodehi 《Journal of Macromolecular Science: Physics》2013,52(10):660-678
The thermal stability of high-density polyethylene, as characterized by an Oxidation Induction Time (OIT) test in the presence of the three additives, antioxidant, carbon black and nanoclay, was investigated. The twenty experiments used were designed by using the Central Composite Design (CCD) method, and the effects of the main parameters and their interactions were analyzed. The results of Analysis of Variance (ANOVA) showed that the antioxidant, nanoclay and carbon black contents, the antioxidant-nanoclay interaction and the antioxidant-carbon black interaction, had significant effects on the thermal stability. By optimization of the percent compositions used, the best composition was obtained, 0.26%, 2.21% and 4.69% for antioxidant, carbon black and nanoclay, respectively, to achieve thermal stability equal to the targeted value of 60?minutes. X-ray diffraction confirmed a weak polymer-nanocaly interaction in the optimal sample structure. The rheology frequency sweep test showed an increase in the elastic and viscous modulus in the optimal sample relative to the control samples. The Melt Flow Index (MFI) test for an optimum sample showed a pseudo-plastic structure with the lowest melt flow index of 0.2614 g/10 min, which was consistent with the results of the complex viscosity, with the optimal sample having the highest value (128500?Pa.s). The density test indicated the most crystalline structure for the optimized sample, with the highest value (0.976?g/cm3) compared to the control samples (0.962 and 0.957?g/cm3 for the polyethylene/nanoclay and the polyethylene/carbon black sample, respectively). 相似文献
13.
采用微波等离子体化学气相沉积(MW-PCVD)和直流热阴极辉光放电等离子体化学气相沉积(DC-PCVD)两种方法相结合,制备出一种吸收辐射的复合金刚石膜,它对宽光谱范围的光辐射具有99%—99.2%的吸收率,同时具有较低的反射率和透过率.随着黑色吸收辐射金刚石层厚度的增加,复合金刚石膜的热导率将小幅度降低,但黑色金刚石膜层厚度小于15 μm时,复合金刚石膜的热导率都在16 W·cm-1·K-1以上,这满足吸收辐射复合金刚石膜的高导热需求.用热阴极DC-PCVD方
关键词:
吸收辐射
光学材料
金刚石
热导率 相似文献
14.
15.
Yongjun Liu Zhizhongsu Xianhui Li Weihong Guo Qiuying Li Chifei Wu 《Journal of Macromolecular Science: Physics》2013,52(1):146-156
A type of grafted carbon black (GCB), prepared with a low molecular weight antioxidant compound by in-situ reaction, was dispersed in poly(ethylene terephthalate) (PET) by a melt-blending process. Dispersion of fillers, volume resistivity, and thermal properties were investigated using scanning electron microscopy, a high-resistance meter, differential scanning calorimetry, and thermogravimetric analysis, respectively. The results show that, compared with carbon black (CB) particles, GCB particles dispersed better in the PET matrix, whereas the conductivity percolation threshold of PET/GCB was higher than that of PET/CB. The addition of GCB or CB elevated the cold crystallization temperature of PET, reflecting the effectiveness of carbon fillers as nucleating agents. But carbon fillers decreased the crystallization enthalpy of PET during both heating and cooling process. Both CB and GCB elevated the starting temperature of thermal degradation of PET and increased the amount of residues for the composites over that of neat PET. 相似文献
16.
Photoacoustic spectroscopy is a method for directly measuring the absorption properties of gases and condensed matter. We have developed a photoacoustic gas cell for a rapid-scan Fourier spectrometer. With this cell we can extend the spectral range down to 180 cm–1; more than one octave lower than previously reported useful broadband measurements. The photoacoustic spectrum of a microscope cover glass was measured from 180 ... 200 cm–1 and normalized with respect to the spectrum of carbon black as a reference material. Starting from the one-dimensional equation of heat conduction we derived an expression for the surface temperature of single and double-layer samples. We calculated the surface temperature of the glass lamella and divided it by the corresponding values for carbon black using the thermal conductivity of carbon black as a fitting parameter. We show that the one-dimensional model calculation reproduces the experimental spectrum over the whole spectral range. 相似文献
17.
The role of backward pyrolysis of carbon during hydrogenation of unstructured carbon black and nanotube growth in a reactor
with hydrogen activated by diffusion through a heated metallic wall is studied. If the wall is heated nonuniformly, the amorphous
unstructured carbon deposit “climbs” in the course of hydrogenation by active hydrogen and deposits again when falling on
the heated metal surface, self-organizing into more ordered nanofibers and nanotubes as a result of forward pyrolysis. It
is shown that this effect can be used for raising the concentration of carbon nanotubes growing on catalyst particles in the
deposited layer. 相似文献
18.
张浩 《光谱学与光谱分析》2017,37(2):412-415
以废弃核桃壳为载体材料、癸酸为相变材料,采用微波加热法制备癸酸/多孔活性炭功能材料。采用傅里叶红外光谱仪对癸酸/多孔活性炭功能材料制备过程各阶段的合成物质进行测试,即活性炭前驱体制备阶段、多孔活性炭制备阶段和癸酸/多孔活性炭功能材料制备阶段。研究癸酸/多孔活性炭功能材料制备过程中多孔活性炭复杂网络结构形成机理、癸酸嵌入方式、癸酸与多孔活性炭的嵌合机理,阐明微波加热法制备癸酸/多孔活性炭功能材料的相关机理。同时采用动态水分吸附分析仪、差示扫描量热仪和环境测试舱对癸酸/多孔活性炭功能材料的湿性能、热性能和吸附性能进行测试。结果表明:癸酸/多孔活性炭功能材料具有发达的孔结构和复杂的网络结构,其中部分孔隙吸附癸酸,部分孔隙吸附甲醛分子,孔隙表面具有亲水性的官能团吸附水分子。癸酸/多孔活性炭功能材料具有较好的湿性能、热性能和吸附性能,其在相对湿度40%~60%,平衡含湿量为0.063 1~0.257 0 g·g-1;相变温度为27.42~33.96 ℃,相变焓为52.14~52.67 J·g-1;经过4 h对甲醛气体的吸附效率为50.57%。 相似文献
19.
The decolorization of acid black 210 by ultrasonic irradiation in the presence of exfoliated graphite was investigated. Low pH value and large exfoliation volume of exfoliated graphite favored the ultrasonic decolorization of acid black 210. The combination method of ultrasonic waves and exfoliated graphite achieved better results than either exfoliated graphite or ultrasound alone. Improved decolorization efficiency has been observed in the present system compared to the process using a combination of ultrasound and activated carbon. In the combination method of ultrasonic waves and exfoliated graphite, approximately 99.5% of acid black 210 was removed using 0.8 g/l exfoliated graphite at a pH of 1 within 120 min at 51 degrees C. 相似文献
20.
Hui Ren Yang-yang Liu Qing-jie Jiao Xiao-fen Fu Ting-ting Yang 《Journal of Physics and Chemistry of Solids》2010,71(2):149-152
Mixture of carbon black, copper and lead was used as catalyst of high-content RDX-composite-modified double base propellant. To enhance the catalytic effect and improve the flaring performance, metal oxide deposited on carbon nanotubes (CNTs) are replaced with afore-mentioned catalyst. A new type of nano-combustion catalyst is synthesized with microemulsion process. In present work, ternary diagram was adopted to analyze the essential factors which affect microemulsion, including temperature, surfactant or cosurfactant and concentration of solution in order to find the best technical parameters and thus to control the core formation and growth of oxides on the nano-template. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) are applied to characterize the products. Through observation of microstructures and analysis of crystal structure, it is confirmed that nano-oxides are deposited on the surface of carbon nanotubes. Its particle size is below 50 nm. According to propellant components, a certain amount of combustion catalyst and RDX will be mixed. PbO·CuO/CNTs can catalyze thermal decomposition of RDX by thermal analysis. The results show that the new catalysts obviously accelerate the decomposition of RDX, and the peak temperature of decomposition reduce by 14.1 °C. The catalytic effect of nano-catalyst is better than original catalyst. 相似文献