Optical properties of carbonized vitrinites

The optical properties have been examined of three vitrinite-rich coals (carbon, daf: 82.5, 88.0 and 93.1%), carbonized at temperature intervals of 25 °C over the greater part of the range 20–950 °C using a heating rate of 2.45 °C/min. The small temperature interval employed has allowed a satisfactory correlation between alterations in the physical state of the carbonized products and fluctuations in the rates of change of their optical properties during carbonization. In general, as temperature rises the variation of all the optical properties reflects the growth and development of organized polycondensed aromatic systems, but in detail reflectivity does not prove as sensitive an indicator of structural changes as do other optical parameters, particularly refractive index. The behaviour of the refractive-index curves of the carbonized vitrinites is governed by changes in the heights of the crystallites forming the aromatic systems. The shape of these curves closely follows the shape of curves produced in independent X-ray diffraction studies giving the heights of crystallites. While all the refractive-index and all the absorptiveindex curves are similar in shape and trend to one another, each of these curves for carbonized coking-coal vitrinite is displaced from the equivalent curves for low-rank bituminous and anthracitic vitrinites. The displacement can be related to the formation of the highly-plastic stage during carbonization of the coking-coal vitrinite, which ultimately yields weakly cross-linked structures with good crystallite orientation, in contrast to the strongly cross-linked structures with lower ordering developed in carbonization of vitrinites of both lower and higher rank.     

Optical properties of carbonized preoxidized vitrinites

The optical properties at 546 nm of three vitrinites (daf carbon contents 82.5, 88.0 and 93.1%) have been examined after pre-oxidation for 14 days at 105 °C and carbonization at intervals of 50 °C within the temperature range 300–800 °C. In general, pre-oxidation prior to carbonization produces only relatively small changes in the trends of optical parameters with temperature that were observed for the same vitrinites when carbonized fresh; the properties of the anthracitic vitrinite displayed little modification. Reflectivities of carbonized pre-oxidized vitrinites of bituminous rank are higher than those for the equivalent fresh vitrinites up to 500 °C, supporting the suggestion that oxidation raises aromaticity and consequently the reflectivity. The most noticeable optical difference occurs with the bituminous-rank vitrinites, in the variation with carbonization temperature of their refractive-index curves, which parallel the behaviour of the L_c curves of X-ray diffraction studies. In particular, the refractive-index track for the carbonized pre-oxidized vitrinite of coking-coal rank no longer shows the same marked contrast to the refractive-index tracks of vitrinites of higher and lower rank, as it does at temperatures above 600 °C when carbonized fresh. The absorptive indices follow similar trends to the reflectivities for all the chars.     

Optical properties of bismuth tellurite based glass

A series of binary tellurite based glasses (Bi(2)O(3))(x) (TeO(2))(100-) (x) was prepared by melt quenching method. The density, molar volume and refractive index increase when bismuth ions Bi(3+) increase, this is due to the increased polarization of the ions Bi(3+) and the enhanced formation of non-bridging oxygen (NBO). The Fourier transform infrared spectroscopy (FTIR) results show the bonding of the glass sample and the optical band gap, E(opt) decreases while the refractive index increases when the ion Bi(3+) content increases.     

Reduction of vitrinites with lithium in ethylamine and the chemistry of the products

The reduction of a set of hand-picked vitrinite concentrates from various American seams with lithium in ethylamine has been studied. When the extent of reduction is plotted against carbon content and previously reported data are included, there is much scatter. Neither the use of ethylenediamine at 100 °C nor the use of extended reaction times has any consistent effect in increasing reduction. The same is true of the increase in extractability by pyridine. Carbonyl absorption in the infrared spectra of the products is thought to be due to reduction of phenols to cyclohexanones. Aliphatic C-H absorption is greatly increased, as expected. There is tendency for the hydroxyl content of higher-rank coals to increase on reduction and of lower-rank bituminous coals to decrease; this may be due to a change with rank of the relative importance of creation of new phenols by ether cleavage and destruction of phenols by reduction to cyclohexanones. Reduction is accompanied by substantial increases in extractability in chloroform (10–35%). Methyl absorption at 1375 cm^?1 in the infrared spectra of the reduced products is greater than that of the raw coal and is quite intense in chloroform-soluble reduction products, as is ¹H n.m.r. resonance in CDCl₃ solution. Evidently analogues of dibenzyl ether and diphenylethane are cleaved during reduction. N.m.r. spectra detect no aromatic-bound hydrogen in the chloroform-soluble products.     

Optical properties of plasticized polycarbonate

Optical properties of polycarbonate plasticized by pentaerythritol tris(1,1,2,3,3,3‐hexafluoropropyl) ether (HFP), diheptadecyl‐o‐phthalate and pentaerythrityl tetrabenzoate (TBP) have been determined at wavelengths from 300 to 700 nm. X‐ray diffraction analysis, which was used to examine the polymer structure, showed that all the plasticized systems were amorphous. HFP and, especially, TBP impeded crystallization of the polymer. Plasticized polycarbonate films remained transparent over long periods of time even if they were heated at a temperature higher than the polymer glass transition temperature. © 2003 Society of Chemical Industry     

Optical properties of carbonized sporinite in vitrinite/sporinite blends

A study is made of the morphological and optical properties of a blend of concentrated sporinite and vitrinite macerals (equal parts) from the same coal carbonized between 400–900 °C at 5 °C/min under nitrogen. Two coals of different rank were used and the results compared with properties of unblended carbonized sporinites. Coke from a blend of low-rank vitrinite and sporinite produced a two-phase optical texture, whereas coke from the medium-rank vitrinite and sporinite mixture produced a three-phase optical texture. A ‘Transitional Zone’ of optical texture was observed at interfaces between carbonized vitrinite and sporinite, this zone being wider for the coal of higher rank. The increase of bireflectance in oil with carbonization temperature of the sporinite in the blends was lower than for the carbonized unblended sporinite, caused by a reduction in fluidity of sporinite with blending. The decrease of refractive index for sporinite carbonized > 600 °C in the blends was lower than that of the unblended sporinite.     

Optical properties of vitrinite carbonized at different pressures

The effect of pressure on the optical properties of cokes from a medium volatile bituminous coal (carbon = 87.9 wt% daf), some carbonized at atmospheric pressure and others under hydraulic pressure (21–310 MPa), over temperatures ranging from 350 to 600 °C at 50 °C intervals, has been studied. The cokes formed at atmospheric pressure developed fine grained mosaics, while medium-flow type mosaics formed in coke carbonized under hydraulic pressure. The thermal decomposition stage began at lower temperatures with increasing hydraulic pressure, resulting in a prolonged devolatilization phase for coke formed at a pressure of 21 MPa. Hence the fluidity of samples carbonized under pressure decreases with increasing hydraulic pressure. Pressure promotes the optical anisotropy apparent from the level of bireflectance. The reflectance of coke formed at atmospheric pressure is higher than that of cokes carbonized under hydraulic pressure, perhaps due to the inhibitory effect of entrapped volatile matter during carbonization under hydraulic pressure. The morphological features of vitirinite carbonized under pressure resemble those of coals naturally affected by heat.     

Optical properties of the CaEuAl3O7 phosphor with dual-activator Eu2+/Eu3+ for multifunctional applications

At present, most blue-red composite LED light sources are widely used in the field of plant lighting. However, their full-width at half-maximum of blue light is too small to meet the requirements of plants for photosynthesis. Herein, a dual-emitting single-phase self-luminescent phosphor CaEuAl₃O₇ (CEAO) is reported in this study, which provides broadband blue emission of Eu²⁺ ions and red emissions of Eu³⁺ ions. According to the optical properties of Eu²⁺ and Eu³⁺ ions in the CEAO phosphor, it can be found that all emissions are consistent with the absorption of chlorophylls and pigment carotenoids. In addition, the temperature sensing based on the fluorescence intensity ratio (FIR) in the CEAO phosphor is also studied and the maximum sensitivity (S) can reach as high as 6.90% K⁻¹ at 313 K. The results indicate that the single-component phosphor CEAO with blue and red double-color emission possesses an outstanding potential in plant growth lamps and optical thermometry applications.     

碳纳米管的光学性质及其在光限幅中的应用

碳纳米管是一种新型的碳材料,具有特殊的结构,独特的力学、电磁学和光学性质,已引起人们的极大兴趣。综述了近年来碳纳米管光学性质的研究进展及其在光限幅中的应用,并对今后的研究方向作了展望。     

Materials Development of Optical Fiber

Traditionally, new materials are developed in response to the requirements of an emerging device technology. In the optical fiber case, development of glass as a transmission medium came as the culmination of a century-long quest for improved broadband telecommunications, a search that established the superiority of light signals transmitted through glass over electronic signals transmitted by wire.     

Effects of Annealing Temperature on Microstructure and Electrical and Optical Properties of Radio-Frequency-Sputtered Tin-Doped Indium Oxide Films

Indium tin oxide (ITO) films (0.3 μm thick), with a doping level of 28 mol% SnO₂, were prepared by a radio frequency magnetron sputtering mehthod. The effects of postannealing on the microstructure and the electrical properties of the ITO films were investigated. The as-sputtered film showed an amorphous structure, whereas the films annealed at 350° and 510°C exhibited crystalline structures with grain sizes of 0.12 and 0.14 μm, respectively. Examination by TEM showed that the postannealing treatment induced SnO₂ precipitates along the grain boundaries. The resistivity increased with increasing postannealing temperatures. The mobility of carriers appears to be responsible for the resistivity increase in these specimens. The mobility change is discussed in connection with the SnO₂ precipitates.     

适于高温压力管道表面应变监测的光纤光栅应变片技术研究

为监测高温压力管道表面应变的快速变化,在制作耐300℃高温光纤光栅基础上,设计了1种适于高温环境下压力管道表面应变检测的光纤布拉格光栅应变片,该光纤光栅应变片选用3只聚酰亚胺涂覆层光纤布拉格光栅和高温恒弹合金基底,经高温粘接工艺进行封装,适用于压力管道二维表面高温应变检测。采用等强度悬臂梁方法,对封装好的高温光纤光栅应变片进行了高温性能和应变性能实验测试,验证了高温光纤光栅应变片的工作性能,给出了高温管道光纤光栅应变片监测系统的技术方案。     

Optical and thermal properties of commercial polymer film,modeling the albedo effect

Greenhouse cladding materials are an important part of greenhouse design. The cladding material controls the light transmission and distribution over the plants within the greenhouse, thereby exerting a major influence on the overall yield. Greenhouse claddings are typically translucent materials offering more diffusive transmission than reflection; however, the reflective properties of the films offer a potential route to increasing the surface albedo of the local environment. We model thermal properties by modeling the films based on their optical transmissions and reflections. We can use this data to estimate their albedo and determine the amount of short wave radiation that will be transmitted/reflected/blocked by the materials and how it can influence the local environment.     

β-SiAlON添加量对矾土基浇注料高温力学性能的影响

研究了加入 β SiAlON对矾土基超低水泥浇注料高温力学性能的影响。结果表明 :加入 β SiAlON能明显提高浇注料试样在 1 30 0℃下的热态强度 ,同时其抗热震性也得到显著改善。产生这些结果的原因是针状和纤维状的 β SiAlON细晶穿插或填充在基质的刚玉骨架结构中 ,起着强化和增韧作用 ,有利于提高试样的高温强度和抗热震性     

Optical properties of poly(vinyl chloride)-gel-based microlens arrays

We use a poly(vinyl chloride) (PVC) gel and an electrode to fabricate adaptive microlens arrays (MLAs). The electrode has a zoned-array pattern. By applying a direct current voltage to the electrode, the PVC gel on each zoned electrode exhibited the character of a lens. The imaging of the MLA can be analyzed using either an optical microscope or a beam profiler or both. The topography of the PVC gel can be measured using an optical surface profiler. Compared to the imaging and focusing, the topographic map can discover additional information about the performances of the MLA. For example, the focal length of each lens in the MLA can be calculated precisely, and the aberration of the MLA can also be evaluated. Results show that the surface profile is an important factor for characterizing the performance of PVC-gel-based MLA. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47407.     

光学活性偶氮染料的光学机理探讨及应用进展

对功能性偶氮染料的光学特性作了机理探讨，分析了其原理、优点及不足；介绍了光学活性偶淡染料的发展状况以及在材料合成和改性方面的应用，指出了当前存在的问题及它的发展潜力。     

自蔓延高温合成耐火材料

介绍了自蔓延法 (SHS)制备耐火材料的原理 ,并对SHS制备耐火材料的影响因素、应用现状和发展前景以及存在的问题进行了系统的论述     

第一性原理计算LiTaO_3光学性质与热力学性质

采用基于第一性原理的赝势平面波法系统计算了LiTaO3晶体的电子结构、光学性质和热力学性质。能带结构表明LiTaO3晶体重要的结构特征是Ta的6d轨道和O的2p轨道存在强的杂化作用。LiTaO3晶体极限折射率为2.4,在55 eV处有明显的光吸收、光反射和能量损失。室温时LiTaO3的恒容热容为24 J/mol·K,800 K时,徳拜温度达到873。     

室温固化高性能胶粘剂的研制

为了改善环氧树脂(EP)胶粘剂对某些金属和非金属材料的粘接性能,采用自制的增韧剂改性EP,制备了一种可室温固化的无溶剂双组分EP胶粘剂。考察了增韧剂用量、不同的室温固化剂及表面处理方法对金属和非金属材料的粘接性能、耐热性能和耐介质性能的影响。实验结果表明,该胶粘剂对金属和非金属都具有良好的粘接性能;用于PVC和ABS粘接时,则被粘材料被破坏;用于聚四氟乙烯(PTFE)和聚乙烯(PE)粘接时,其最高剪切强度分别为1.9 MPa和1.8 MPa。     

Preparation of novel titanium-niobium-oxygen composite ceramic with excellent thermoelectric properties using the high-pressure and high-temperature method

Titanium oxide is a promising thermoelectric material because of its high stability and low cost. We synthesize novel titanium-niobium-oxygen composite ceramics directly from elementary substance Nb and TiO₂ under high-pressure and high-temperature (HPHT) in this work. Elemental substance Nb will reduce TiO₂ to Magnèli phase titanium oxide at high pressure and high temperature. In this process, elemental substance Nb is oxidized to various niobium oxides. The experimental results show that the composite ceramics have a special 'pore' microstructure, and their thermoelectric and mechanical properties are very prominent among metal oxide thermoelectric materials. After repeated tests, the optimum concentration sample zT value is 0.313 at 973 k, with a Vickers hardness of 7.06. This work provides a novel concept for improving the performance of TiO₂ by reducing it with metal elementary substances other than Ti.