共查询到20条相似文献,搜索用时 218 毫秒
1.
2.
3.
针对传统取样分析技术会破坏物证和综合考察样本作为混合物在多维度上的差异性,提出一种基于二阶导数红外光谱结合模式识别对轮胎橡胶颗粒快速准确鉴别的方法。采集并分析不同品牌共计96个轮胎橡胶颗粒的红外谱图及其二阶导数谱图,同时预处理采用自动基线校正、峰面积归一化和Savitzky-Golay平滑,建立判别分析模型,从而实现其品牌间的准确区分和认定。红外二阶导数谱图呈现出许多原始谱图中被掩盖谱峰的斜率变化特征,将样本谱图间的差异更为明显的表示了出来,结合原始谱图和其二阶导数谱图,得出实验样本主要由丁苯橡胶、顺丁橡胶和异戊橡胶3种类型。原始谱图判别预测模型分类准确率为95.83%,二阶导数判别预测模型分类正确率为100%,其区分能力更强,二阶导数结合判别分析可有效开展对轮胎橡胶颗粒的区分鉴别,其构建的模型分类效果更好。以品牌为单位,进一步对丁苯橡胶等3种类型的样本展开模式识别工作,得出其判别预测模型均实现了样本品牌间100%的区分和归类,实验结果理想。利用二阶导数红外光谱结合模式识别可实现对轮胎橡胶样本的准确识别与分类,方法具有一定的普适性和借鉴意义,可为其他物证的鉴别与分析提供一定的参考。 相似文献
4.
用氯丁橡胶(CR)共混聚氨酯(PU)制备了不同红外透明性的粘合剂,并分别添加不同含量的铜粉等填料,制得不同发射率的红外隐身涂层。对粘合剂的红外光谱、发射率及涂层的发射率、微观形貌等进行了分析。结果表明,随粘合剂中聚氨酯含量的增大,粘合剂的透明性变差、发射率增大,涂层的发射率也增大;当铜粉添加量较大时,涂层发射率较小,粘合剂的红外透明性对涂层发射率的影响也相对小一些;并着重对其原因进行了分析。 相似文献
5.
目的 综述近年来国内外先进的红外隐身防护材料技术的研究进展,并对红外隐身材料的未来进行展望。方法 从红外探测技术与红外隐身原理出发,着重介绍低发射率材料、控温材料、新型智能红外隐身材料以及协同复合材料等一系列有优异性能的材料。结果 红外隐身可通过降低物体表面温度及降低物体表面辐射率来实现,依据这两方面原理研制的红外隐身防护材料具有良好的隐身效果。结论 不同种类的红外隐身材料具有不同的特点,已广泛运用于军事装备、织物等方面,但依然存在一些不足,未来要针对不同应用环境要求进一步优化,以期满足现代化战争需求。 相似文献
6.
7.
8.
以不同紧度的纯棉织物为基材,采用射频磁控溅射技术进行金属化处理,制备出表面覆有不同材料(Cu、Al、Ag)的金属化织物。建立正交实验,系统研究了织物紧度、沉积时间、镀层金属种类对织物防红外辐射性能的影响。借助原子力显微镜(AFM)对溅射前后织物表面的形貌和结构进行了分析;利用傅里叶红外变换光谱仪、紫外光分光光度仪和红外照相机对织物防红外效果进行测试。结果表明:金属种类是影响红外反射率的主要因素(透过率强度对比:CuAlAg),其中紧度83%、沉积时间60min的镀铜织物防红外效果最好。 相似文献
9.
MXene是一大类二维过渡金属碳氮化合物,其丰富的组分、二维原子层结构、金属电导和活性表面等特性使其与不同波段的电磁波(可见光、红外、太赫兹、微波波段等)产生独特的相互作用,并衍生了多种电磁功能应用。在红外波段, MXene具有宽域的红外辐射特性,活性表面使其具备可调的红外吸收。近年来, MXene的上述性质引起了广泛研究兴趣。本文首先对不同MXene组分的本征红外辐射特性及调控策略进行了系统总结,并简要介绍其代表性红外应用,重点讨论MXene在这些应用中的贡献和作用机制,包括红外识别/伪装、表面等离激元、光热转换、红外光电探测等。最后,对MXene红外功能应用的未来发展方向进行了展望。 相似文献
10.
11.
A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils. 相似文献
12.
Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion. 相似文献
13.
In this paper, the principle of spurting take off lacquer were introduced; and with orthogonal method the unsaturate polyester was prepared ;it was easy to peel airplane paint layer off with this material and equipment. 相似文献
14.
Sandwich panels utilizing honeycomb cores result in lightweight, high-strength units that are very rigid. Indeed, they give honeycomb panels the best strength-to-weight ratio of any construction type available. Conventionally, the wax is poured into the cell of the core to strengthen the structure and prevent the core from being crushed during milling. Much time and labor is required to wax, mill, and clean the cores. In this study, the process of pouring wax into the core was skipped. In other words, the cutter directly milled the core. Experiments showed that the compressive strength of the core produced without wax stabilization was only 3% lower than that of cores produced using the traditional method. In addition, the drum peel strengths of cores produced without wax stabilization were 38.4% higher than cores produced using the traditional method, in which residual wax seriously polluted the adhesive. It was also found that eliminating the wax process can reduce costs. 相似文献
15.
The end of over unit products of more than Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits beer wine yellow wine fruit syrup wine others cover over % of the national top-branded liquor products.…… 《中国标准化(英文版)》2008,25(1):30
The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.…… 相似文献
16.
Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster. 相似文献
17.
N.A. Odintsova N.V. Ageenko K.V. Kiselev N.M. Sanina E.Y. Kostetsky 《International Journal of Refrigeration》2006,29(3):387
We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes. 相似文献
18.
Muhammad Harris Johan Potgieter Richard Archer 《Materials and Manufacturing Processes》2019,34(6):701-713
Polylactic acid (PLA) is one of the most widely used open source fused filament fabrication materials due to its ease of extrusion, biodegradability, and mechanical strength. The mechanical strength of PLA largely depends on the proper growth of its semi-crystalline structure, which can be severely impaired by a low rate of crystallization, particularly in open source printers. This can be further aggravated by the non-uniform thermal distribution of heat that causes improper curing among the extruded beads of the printing material. As a result, PLA printed on open source printers does not achieve the best mechanical properties. This research, for the first time, proposes an additive-free solution implemented through a detailed set of experimentation to improve the curing rate through in-process temperature variations to cure the joints among the beads. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy is used to confirm the improvements in the bead joints. This work is conducted in two phases of experiments. In the first phase, a full factorial ANOVA is used to investigate various process parameters and the important variables are used in the second phase to print test specimens in four different sets. 相似文献
19.
David R. Smith F. R. Fickett 《Journal of research of the National Institute of Standards and Technology》1995,100(2):119-171
Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability. 相似文献
20.
Fco. Javier Franco Pérez Marc Gener Moret 《Materials and Manufacturing Processes》2017,32(7-8):876-884
ABSTRACTThe production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials. 相似文献