A facile method to prepare ultra-wideband anti-reflective borosilicate glass with subwavelength structure surface

Anti-reflective (AR) films have been widely investigated due to their various applications in optoelectronic devices. Among all the investigation, the manufacturing method is the most popular research field which directly determines the performance of anti-reflective films. Herein, Na₂HPO₄ and AlCl₃ mixed neutral solution were used to etch the surface of K9 glass matrix to obtain the AR structure. The morphology of SEM images indicated that subwavelength structure (SWS) was formed on the glass surface via precisely controlling the solution concentration, treatment time and temperature. Owing to the porous structure, the refractive index mutation of the interface between air and glassss can be effectively weakened. Therefore, the integral transmittance, covering the whole visible light (VIS) to near-infrared (NIR) wavelength (300–2500 nm), of glass matrix was increased remarkably to 95.77%, much higher than 87.72% of blank glass, achieving the effect of ultra-wideband anti-reflection. Particularly, the transmittance at 520 nm and 1990 nm can even reach to 99.14% and 97.86%, respectively. According to the composite analysis and reaction process, Al³⁺ ions act as both the regulator of the solution pH and part of the new-formed glass skeleton, resulting in the more uniform and regular SWS on the glass surface. Moreover, in virtue of -OH in silanol (Si-OH) on the expanded glass surface attracting more H₂O molecules or additional silylation modification on glass surface repulsing H₂O molecules, the surface characteristics of AR glass with SWS films can be easily turned between hydrophilic and hydrophobic in order to meet the requirements of various application environments. These ultra-wideband AR glasses with controllable hydrophilic and hydrophobic properties are expected to be applied in many optoelectronic fields.     

采矿活动对矿山地质环境影响评价及其治理措施

矿山开采可导致多种地质灾害。研究了矿山地质灾害现状,认为地质灾害危险性集中发育区分布面积约为4.093 3 km²,地质灾害危险性一般区分布面积约为10.735 2 km²,并研究了采矿活动对含水层、地形地貌景观、土地资源等影响破坏情况及相关评价。研究得出,采空区及其影响范围内对含水层影响和破坏严重,面积1.40 km²,对含水层影响和破坏较轻,面积12.61 km²;对地形地貌景观影响程度严重区面积1.11 km²,影响程度较轻区面积12.90 km²;对土地资源影响影响程度严重区面积1.76 km²,影响程度较轻区面积12.25 km²。基于此,提出了矿山地质环境治理措施,主要有采空区防治措施、地质灾害防治措施、地貌景观修复及矿山复绿措施、含水层保护措施、土地复垦措施、矿山废水废渣综合治理措施,研究为后期矿山环境修复具体实施提供了技术支持。     

A skeletal n-butane mechanism with integrated simplification method

A new skeletal mechanism of n-butane is developed for describing its ignition and combustion characteristics applicable over a wide range of conditions: initial temperature 690–1430 K, pressure 1–30 atm, and equivalence ratio 0.5–2.0. Starting with a detailed chemical reaction kinetic model of 230 species and 1328 reactions (Healy et al., Combust. Flame, 2010), the directed relation graph method is applied as the first step to derive a semi-detailed mechanism with 134 species. Then, the reaction path analysis in conjunction with temperature sensitivity analysis is used to remove the redundant species and reaction paths simultaneously under the condition of low-temperature and moderate-to-high temperatures, respectively. Finally, a skeletal n-butane mechanism consisting of 86 species and 373 reactions can be obtained. Mechanism validation indicates that the new developed skeletal mechanism is in good agreement with the detailed mechanism in predicting the global ignition and combustion characteristics. The new skeletal mechanism is further validated using extensive available literature data including rapid pressure machine ignition delay time, shock-tube ignition delay time, laminar flame speed, and jet-stirred reaction oxidation, covering a large range of temperatures, pressures, and equivalence ratios. The comparison results demonstrate that a satisfactory agreement between predictions and experimental measurements is achieved.     

A physically based extreme value characterization of material fatigue

The most relevant aspects of material fatigue, i.e., the size of fatigue initiating defects, the fatigue limit, and the fatigue life can be characterized by means of extreme value distributions. The present work introduces a new physically based extreme value distribution. This new distribution function is derived by assuming that the size of the fatigue initiating defects in a component are log-normally distributed. It is demonstrated how the different aspects of material fatigue can be related to each other and consistently characterized with a single type of distribution function.     

Measurement of lift-off using the relative variation of magnetic flux in pulsed eddy current testing

Measurement of lift-off can be used to assess the thermal insulation thickness and it has the potential to reduce the lift-off effect in pulsed eddy current testing. In this paper, first, the relative variation of magnetic flux is proposed as a feature for the measurement of lift-off. And then, how to directly obtain the key parameters of the feature from the testing signals is provided. At last, the validity of the feature is verified by simulations and experiments, respectively. The results show that the feature is suitable when the lift-off is tens of millimeters and the plate is ferromagnetic.     

Improvement in fracture strength in electrically conductive AlN ceramics with high thermal conductivity

It is possible to impart electrical conductivity to insulating aluminum nitride (AlN) ceramics by precipitating a yttrium oxycarbide grain boundary phase with electrical conductivity. However, previously, sintering at high temperature was required to increase the electrical conductivity through the transformation of the grain boundary phase from yttrium aluminum oxide (Al₂Y₄O₉) to rare-earth oxycarbide. As a result, the increase in electrical conductivity was accompanied with a considerable decrease in the fracture strength due to grain growth of AlN. In this study, sintering temperature and additive compositions were investigated to maintain the high strength of electrically conductive AlN without losing the high thermal conductivity.     

基于语义对象网络模型的产品知识表达方法

为表达产品知识及其语义内涵和约束关系,提出采用语义对象网络模型（Semantic Object Semantic Networks,SOSNs）表达产品知识。SOSNs是基于图并结合面向对象方法表达的知识模型,其中节点表示产品语义对象,有向边显性定义语义对象之间的语义关系,这种基于图的语义模型能够清晰的表示产品功能、行为、原理、结构、配置管理、约束等知识及其语义关系,将与产品开发相关的知识集成为一个逻辑整体,形成分层的结构化语义对象网络结构,便于组织和管理产品知识,易于实现知识的共享和重用。     

A spectral-mathematical strategy for the identification of edible and swill-cooked dirty oils using terahertz spectroscopy

Effective technique and procedure based on the terahertz (THz) spectroscopy and mathematical methods, named THz Mathematics (T-Math), have been developed for the precise and rapid identification of edible oil from a series of typical swill-cooked dirty oils in daily life. Differences can be observed in the absorbance spectra of edible and dirty oils, while the waveforms were very similar. Principal component analysis (PCA) and support vector machine (SVM) were employed for the identification of edible or swill-cooked oil classification. Compared with dirty oils, normal edible oil had the largest first principal component (PC 1) score with a contribution rate of 97.4%. The PC 1 score deviations of edible oil and dirty oils varied from ∼0.5 to 2.3. Meanwhile, by using SVM leave-one-out cross-validation, the swill-cooked oils can be directly identified with the precision of 100%. This study proved that the developed method was very suitable for the rapid determination of swill-cooked oils in food safety field.     

Two-parameter Lorentzian distribution for monitoring physical parameters of golden colored fruits during drying by application of laser light in the Vis/NIR spectrum

Inadequate drying conditions of tropical fruits can alter the cellular structure and chemistry, which can lead to undesirable characteristics of the final product. The purpose of this research is to test the feasibility of light scattering of three laser sources operating in the Vis/NIR range by calculating a two-parameter Lorentzian distribution (LD) for quality assessment of two golden-colored fruits, namely mango and litchi, during drying. Linear mixed models showed that blue light at 473 nm was the most adequate to monitor changes in browning (R² = 0.81) and moisture content (R² = 0.80) of litchi. For mango, NIR light at 785 nm was affected by the hardness (p < 0.001), whereas moisture content showed a strong influence on the calculated LD functions at both 532 (p < 0.001) and 785 (p < 0.05) nm with a good fitting of the prediction model (R² = 0.91). Laser light can provide an economically-effective solution to obtain information from the fruit tissue non-destructively during industrial drying processes.Industrial relevanceConvective drying is still the most common dehydration technique in industrial applications, while many agricultural products remain susceptible to thermal damage. Quality parameters of these products are not only affected by drying conditions, but are also crop-specific. Meanwhile, the use of laser light backscattering is an innovative and rapid technique to estimate a range of quality parameters during drying of agricultural products. The results of this research provide a basis for robust, in-line quality control during industrial drying processes. In this respect, the application of laser backscattering systems presents many advantages: rapid, real-time product information, eradication of laborious and costly destructive analytical methods, continuous monitoring to avoid over-drying (improved energy efficiency) and quality losses, easy integration into existing drying systems and high resistance to harsh conditions typically found in dryers such as high temperatures and dust.     

Kinetics of non-isothermal oxidation of AlN powder

The non-isothermal oxidation of AlN powder has been studied, based on which a new formula has been suggested to express the reacted fraction of the oxidation as a function of oxidation time, oxygen partial pressure, the particle size, as well as the temperature increasing rate explicitly. The application of this new model to the oxidation of AlN powder shows that this new model can give a more accurate and reasonable result. The diffusion activation energy of AlN powder is extracted to be 356.3 kJ/mol.