生物医学工程用炭质植入物和吸附材料

综述生物医学工程用炭质植入物和创面炭质吸附材料的实验分析，炭质植入物和炭质吸附材料与生物体有着良好的亲和性和相容性及可设计性。     

矿热电炉与炭质电极的使用和生产

矿热电炉是生产铁合金和工业硅、黄磷、刚玉、电石等材料的冶炼设备，用途十分广泛。矿热电炉使用的导电材料有电极糊（自焙电极材料）、炭质电极和石墨电极，三者各有优缺点，中国在生产工业硅的敞口型矿热电炉上，炭质电极正在占据主要位置，但在生产黄磷的封闭型矿热电炉上仍以使用石墨电极为主。国外生产黄磷多数已经使用炭质电极，炭质电极的生产和使用已经引起中国炭素行业和矿热电炉冶炼工业界的重视。本文简要介绍矿热电炉的特点、炭质电极的使用和生产，介绍美国、德国炭质电极的生产规格、品种、质量指标等。     

壳聚糖基大孔炭质整体材料的制备及其对痕量二氧化硫的吸附性能

以壳聚糖为碳源,综合采用冰模板技术和低温热解炭化技术,制备出具有蜂窝状孔结构特征的大孔炭质整体材料,研究了此类新材料对痕量二氧化硫的吸附性能及再生能力。结果表明,大孔炭质整体材料蜂窝状孔结构的形成及其规整程度与冰模板过程的冷冻时间等因素密切相关;200℃下低温热处理可得到具有丰富表面含氮官能团的大孔炭质整体材料;经氨水溶液中的离子交换功能化处理后,该大孔炭质整体材料对低浓度SO₂的吸附容量显著提高,可达到57 mg·g^-1;吸附饱和后,经空气简单吹扫处理,大孔炭质整体材料即可大部分再生,少数不可再生部分是由于质子化的氨基与亚硫酸根和硫酸根在吸附过程中形成了不可逆化学吸附产物季铵盐所致。壳聚糖基大孔炭质整体吸附剂材料有望在污染空气的脱硫净化,特别是在质子交换膜燃料电池的阴极空气脱硫净化方面发挥重要作用。     

太白县油房沟石墨矿地质特征及成因浅析

太白油房沟石墨矿为典型的沉积变质型矿床。区内地层主要为岩浆岩-沉积岩建造。赋矿岩层为千枚岩状黑色炭质板岩,矿体受沉积作用的控制大多呈层状展布。本文通过作者野外地质工作及结合最新研究成果,综合分析矿区地质及构造背景,确定了本区矿床成矿规律,为下一步工作提供了一定的指导意义。     

高炉炉底用炭质浇注料的研究与耐用性能分析

高炉用炭质浇注料的热导率、耐水性、耐酸碱性是影响炭质炉衬冷却效果的关键.为此,通过分析含碳化硅的炭质浇注料及以炭素为主的炭质浇注料的性能,发现含碳化硅的炭质浇注料耐压强度较高;而以炭素为主的炭质浇注料干燥强度高,高温烧后耐压强度大幅度降低.含碳化硅的炭质浇注料耐水性较好,但经2％(w)氢氧化钠溶液浸泡后完全松解.因此,...     

针状焦技术的研究现状

针状焦是一种新型炭材料,它是随着炭质中间相理论的研究而发展起来的.本文综述了针状焦的发展历程、成焦机理、原料和种类、性能指标和评价、工业生产主要问题以及研究新进展.     

淀粉基炭微球中无机催化剂的催化作用

淀粉是一种新兴的炭质材料前躯体,它具有传统生物质材料的很多优点,比如:可再生、低污染和经济性等,同时还具有碳元素含量高、拥有天然球形结构、低杂质含量等特点。以淀粉为原料,采用不同的处理方法能得到不同炭质结构的产物。将马铃薯淀粉作为原料,然后分别选择使用磷酸、磷酸氢二胺和氯化铵等作为催化剂对淀粉炭化过程中产生的催化作用进行分析,研究了经过不同催化剂处理所生成的淀粉基炭微球的炭质结构。     

炭质材料在活化过硫酸盐高级氧化技术中的应用进展

在应用过硫酸盐高级氧化技术降解有机污染物的过程中,开发经济、高效、安全的新型活化技术至关重要并成为目前的研究热点。近年来,炭质材料凭借其自身独特的优势及发展前景迅速受到广泛的关注,有望成为应用于高级氧化技术的新一代绿色催化剂。本文综述了近几年来国内外关于各种炭质材料在活化过硫酸盐氧化技术中的研究应用进展,包括活性炭活化、不同类型的生物炭活化、表面化学改性炭材料活化、杂原子改性炭材料活化、炭材料负载金属及金属氧化物活化以及炭材料与其他技术耦合活化过硫酸盐降解有机污染物的研究现状,并探讨了该技术在应用过程中的运行成本问题,最后提出了该技术目前面临的问题及未来发展方向,期望为促进炭质材料活化过硫酸盐高级氧化技术的进一步推广和应用提供参考。     

关于解决炭质滑板弯曲问题的探讨

炭质滑板是电力机车受电弓电触点的一种新型非金属导电材料,在铁路、矿山的运输电气化建设中占很重要地位,很有发展前途。国产炭质滑板历史较短,工艺技术还欠成熟。近年来,我厂生产炭质滑板中存在的重要问题是焙烧后滑板弯曲,本文就解决这一问题谈一点体会。     

炭质材料对连铸保护渣烧结性能的影响

借鉴耐火材料烧结性能的研究方法 ,通过研究连铸保护渣的炭质材料种类 (中超炭黑、半补强炭黑、鳞片石墨、土状石墨和焦炭 )及含量对烧结性能的影响 ,提出了评价保护渣烧结特性的方法和影响渣圈形成的原因。结果发现 :致密化起始温度Tq和致密化速率U可作为衡量渣圈生成的主要指标 ,U高或Tq低的保护渣的烧结倾向大 ,在使用中易结渣圈 ;在保护渣中加入炭质材料 ,可以降低保护渣的U ,从而抑制保护渣的烧结 ;在试验所用的炭质材料中 ,炭黑降U的效果优于石墨 ,其中中超炭黑的效果最好 ,其次为半补强炭黑和鳞片石墨。     

Pyrolytic formation and photoluminescence properties of a new layered carbonaceous material with graphite oxide-mimicking characteristics

Thermal carbonization of bis(2-chloroethyl)amine hydrochloride at 260 °C in air leads to a new, functional layered carbonaceous material that, although different in structure and composition, shares similar characteristics as the well-known graphite oxide. Specifically, the molecularly derived carbonaceous solid is layered with relatively small lateral dimensions, highly dispersible in water providing clear colloidal sols and possesses ion-exchange properties. The carbonaceous solid strongly fluoresces in the visible, when stimulated with a wide range of excitation wavelengths. Overall, the method presents an alternative synthesis towards molecularly derived layered carbonaceous materials with novel properties.     

Carbon paste electrodes made from novel carbonaceous materials: Preparation and electrochemical characterization

This work describes the preparation of novel carbon paste electrodes by mixing of different carbonaceous materials with an organic binder (Nujol). All carbonaceous materials employed in this study were synthesized from the pyrolysis of different poly(furfurylalcohol)-based precursors, and will be referred here as glassy carbon (GC), template carbon (TC), porous carbon foam (CF) and porous carbon microspheres (CM). Studies on the best carbon/Nujol ratio, potential window and electrochemical reactivity were carried out for each carbonaceous material, and the results are discussed in terms of the materials structure and morphology. In order to comparison, similar electrodes were made from commercial graphite. The possibility of utilization of the different electrodes in electroanalysis and electrocatalysis is discussed.     

On the hierarchy of the influences of porous and electronic structures of carbonaceous materials on parameters of molecular storage devices

The relation between porous structure, electronic properties of carbonaceous material and the capacitance of its interface with an electrolyte is discussed. It is shown that, in an electric double-layer, the contribution of pseudocapacitive charge accumulation is determined, mainly, by the position of Fermi level in the carbonaceous material and depends on thermodynamic parameters of ions in the electolytic solution. The sizes of the pores in which the processes of capacitive and pseudocapacitive charge accumulation dominate are determined. Theoretical analysis of the processes taking place on the nanoporous carbon|electrolyte interface has made it possible to recognize the intercalative nature of pseudocapacity and to find the criterion of its manifestation in the form of the formation of a continuous series of stable valency phases.     

Anomalous Defects and Dynamic Failure of Armor Ceramics

The ballistic performance of state-of-the-art silicon carbide armor material can exhibit a fairly wide variability in certain test configurations, which, it is proposed, may be due to the presence of large (>0.1 mm), rare defects, termed, herein, "anomalous" defects. SiC rubble resulting from ballistic tests was examined, as were quasi-static test samples. Ballistic fragment fracture surfaces revealed large carbonaceous defects that seemed to affect fracture path and mode. Low-strength biaxial flexure samples demonstrated similar defects (>0.1 mm) as failure origins. Carbonaceous defects similar in appearance but smaller in size were also found at the fracture origins of SiC bend bars. Frequently, alumina inclusions were found within the carbonaceous discontinuities. These alumina inclusions may cause the graphitic regions to form during sintering. The random distribution of such large, rare carbonaceous discontinuities from sample-to-sample, as well as batch-to-batch variability, may explain high ballistic variability for SiC armor ceramics.     

Pyrolytic lignin removal for the valorization of biomass pyrolysis crude bio‐oil by catalytic transformation

BACKGROUND: The catalytic processes for valorizing the bio‐oil obtained from lignocellulosic biomass pyrolysis face the problem that a great amount of carbonaceous material is deposited on the catalyst due to the polymerization of phenol‐derived compounds in the crude bio‐oil. This carbonaceous material blocks the catalytic bed and contributes to rapid catalyst deactivation. This paper studies an on‐line two‐step process, in which the first one separates the polymerizable material and produces a reproducible material whose valorization is of commercial interest. RESULTS: The establishment of a step for pyrolytic lignin deposition at 400 °C avoids the blockage of the on‐line catalytic bed and attenuates the deactivation of a HZSM‐5 zeolite based catalyst used for hydrocarbon production. The origin of catalyst deactivation is coke deposition, which has two fractions (thermal and catalytic), whose content is attenuated by prior pyrolytic lignin separation and by co‐feeding methanol. The morphology and properties of the material deposited in the first step (pyrolytic lignin) are similar to lignins obtained as a by‐product in wood pulp manufacturing. CONCLUSIONS: The proposed reaction strategy, with two steps (thermal and catalytic) in series, valorizes the crude bio‐oil by solving the problems caused by the polymerization of phenolic compounds, which are obtained in the pyrolysis of the lignin contained in lignocellulosic biomass. Given that a by‐product (pyrolytic lignin) is obtained with similar properties to the lignin from wood pulping manufacturing, the perspectives for the viability of lignocellulosic biomass valorization are promising, which is essential for furthering its implementation in biorefinery processes. Copyright © 2009 Society of Chemical Industry     

CH_4-CO_2重整转化反应器热平衡和流体阻力特性的研究

基于炭催化剂特性、原料气组成和重整转化反应器的尺寸参数,建立了重整反应器体系的物料平衡和热平衡方程;并针对形状不规则炭催化剂粒度分布的特点,研究了重整转化反应器内流体阻力特性。研究结果表明:1)CO和H2O的生成热量是系统的主要放热源,占系统热量收入的71.03%,吸热的主要反应为CH4和CO2的转化反应,其吸热量占系统热量支出的33.54%,高温气体带走的大量热量占54.11%,散热量占13.51%;2)炭催化剂床层的流体阻力是重整转化反应器流体阻力的主要部分,炭催化剂粒度越大,炭催化剂床层的阻力越小,最适宜粒度组成是25～35mm的占80%,15～25 mm的占15%,5～15 mm的占5%,此时炭催化剂床层的流体阻力为313.5Pa/m。     

Activated carbon from lignocellulosic biomass-phenolic resin

Lignocellulosic biomass of agricultural/industrial by-products residues was taken after the pressing and extraction of olive-oil and lignin Klason and a-cellulose were isolated. Also, phenol-formaldehyde was polymerized by using an acid catalyst. Various mixtures of lignocellulosic materials and novolac resin were cured with haxamethylenetetramine and then pyrolyzed up to 1000°C. The IR-Spectrum of the cured material consisted of 20% novolac and 80% cellulose is practically similar to that of 100% cellulose. The corresponding material with lignin Klason instead of cellulose has different IR-Spectrum compared to that of 100% lignin, because of additional reactions taken place between lignin and novolac under curing conditions. The weight losses, the shrinkages at the end of the pyrolysis, the specific surface area of the carbonaceous materials produced and their adsorption abilities of methylene blue and alizarin yellow from aqueous solutions were determined. The material consisted of 20% novolac and 80% cellulose or 80% lignin, appears as optimum characteristics of production process. The experimental results are also discussed under the aspect of sample shapes that influence the adsorption as well as the electron donor–acceptor (EDA) interactions between the functional groups of dyes and the carbonaceous materials. © 1994 John Wiley & Sons, Inc.     

Methane activation by surface oxygen in calcia-stabilized zirconia

Methane activation at 450–700°C by 14 mol% calcia-stabilized zirconia was studied by the transient reaction of pure methane with the oxidized material. Three distinct sequential reaction regimes are observed. Initially, methane oxidation rates are similar to those in cofed methane–oxygen mixtures. After a small amount of oxygen (amount) is removed from the material, the reactivity of the material suddenly increases while a larger amount of oxygen, roughly equivalent to 1 surface layer, is removed. Finally, after this reductive phase, methane continues to react rapidly to deposit a surface layer of carbonaceous material which can be removed by reoxidation. This cycle can be repeated.     

Electrical conductivity of carbonaceous powders

The present paper deals with the electrical conductivity of a number of carbonaceous powders undergoing a low compaction. It is shown that the contributions to the conductivity of such samples are too numerous and too complex to be solved exactly. Hence, several criteria are proposed in order to quantify the behaviour of moderately compressed powders, and thus derive several useful parameters characterizing their grains. Thus, their morphological characterization is shown to be feasible from such electrical measurements. For that purpose, a known weight of material is poured into a thick glass cylinder and is moderately compressed between two stainless steel pistons. A number of different carbonaceous powders having various morphologies, from almost spherical to disk- or needle-shaped, have been investigated. During the compaction, both the electrical conductivity σ and the volume of the sample are simultaneously measured. The results are found to depend strongly on the initial height h of the powder column. The non-monotonic behaviour of σ versus h is studied for each available material. Arguments are given for retaining only the sample size which leads to the highest conductivity. The so-called general effective media (GEM) equation is then applied to the corresponding data of σ versus Φ, where Φ is the volume fraction of grains in the column. In this context, the grains are assumed to behave like either oblate or prolate spheroids, depending on the material. The fitting procedure requires the knowledge of both the apparent density of the powder in the non-compacted state, and that of the grains, and thus uses only two adjustable parameters. For each material, average aspect ratios are derived from the fits of the GEM equation and are shown to be strongly consistent with the expected morphologies.     

A novel method of examining carbonaceous deposits on spent catalyst surfaces

Xenon ion-bombardment used in conjunction with Auger electron spectroscopy was able to discriminate two types of carbonaceous materials accumulated on the surfaces of iron oxide and rhenium/iron-oxide catalysts spent for CO hydrogenation at 250°C and 2.1 MPa. One of the carbonaceous materials was easily eliminated from the surfaces by ion bombardment or by heat-treatment in vacuo at 150°C. On iron oxide only this “soft” carbonaceous material was present. On rhenium/iron oxide, bombardment-resistant “hard” carbonaceous material was also found. The presence of this hard carbonaceous material had little effect on the level of CO hydrogenation activity or the deactivation behavior of this catalytic system.