MgO assisted densification of highly transparent YAG ceramics and their microstructural evolution

In current study, various amounts of MgO single dopant was adopted to fabricated high quality transparent YAG ceramics, by utilizing a simple one-step solid state reaction sintering method in vacuum. At a MgO doping amount of only 0.03 wt.%, YAG transparent ceramics with a transmittance of 84.5% at 1064 nm could be obtained, after sintering at 1820 °C for 8 h. The microstructure evolution and optical property of as-fabricated YAG ceramics as a function of MgO doping concentration were systematically investigated. MgO dopant could effectively promote densification of YAG ceramics when the sintering temperature was lower than 1660 °C, and dramatically accelerate its grain growth between 1540 °C and 1660 °C. Further increase the doping amount of MgO would not benefit to the optical quality of YAG ceramics, and the intragranular pores as well as the Mg-riched secondary phase were observed from the MgO heavily doped ceramics.     

三号胆盐的研制

研究建立了一种三号胆盐（ＢＳＮＴ）的制备工艺，本工艺ＢＮＳＴ产品的化学组成及其各项理化指标均达到了进口三号胆盐（ＩＢＳＮＴ）的水平，可以考虑代替ＩＢＳＮＴ使用。     

硫酸钾-硫酸-水体系液固相平衡及其应用

在研究30℃下K2SO4－H2SO4－H2O体系相图特性的基础上，探讨了常温下在液相中用水分解硫酸氢钾制取硫酸钾的相平衡原理，并初步拟定了原则流程。研究表明，该流程主要由常温下固体的溶解与液固分离这些技术上非常成熟的单元操作组成，是一种值得研究开发的具有光明前景的新工艺。     

精密传动链精度的测试分析

传动链误差是分析研究具有内联系传动链机床的一个重要问题,本文以滚齿机分度链为研究对象,采用现有设备拾取原始数据——传动链误差,然后在微机上实现误差源诊断;同时通过计算机仿真,讨论了一种实时补偿机床传动链误差的方法。     

新型铁钙脱氧剂性能研究

研制一种强度好和耐硫的铁钙脱氧剂,以保护中变催化剂。考察了不同中和剂制得的铁钙复合氧化物脱氧剂A、B的强度和脱氧活性以及使用条件对脱氧性能的影响。结果表明,脱氧剂A还原后强度好,水煤气条件下,温度≥300 ℃,空速4 000 h^-1,可将体积分数0.5%~1%的O₂脱至10×10^-6以下,并且耐高硫冲击。     

Data driven uncertainty evaluation for complex engineered system design

Complex engineered systems are often difficult to analyze and design due to the tangled interdependencies among their subsystems and components. Conventional design methods often need exact modeling or accurate structure decomposition, which limits their practical application. The rapid expansion of data makes utilizing data to guide and improve system design indispensable in practical engineering. In this paper, a data driven uncertainty evaluation approach is proposed to support the design of complex engineered systems. The core of the approach is a data-mining based uncertainty evaluation method that predicts the uncertainty level of a specific system design by means of analyzing association relations along different system attributes and synthesizing the information entropy of the covered attribute areas, and a quantitative measure of system uncertainty can be obtained accordingly. Monte Carlo simulation is introduced to get the uncertainty extrema, and the possible data distributions under different situations is discussed in detail. The uncertainty values can be normalized using the simulation results and the values can be used to evaluate different system designs. A prototype system is established, and two case studies have been carried out. The case of an inverted pendulum system validates the effectiveness of the proposed method, and the case of an oil sump design shows the practicability when two or more design plans need to be compared. This research can be used to evaluate the uncertainty of complex engineered systems completely relying on data, and is ideally suited for plan selection and performance analysis in system design.     

Microstructures and High-Temperature Friction–Wear Performance of Laser-Remelted WC-12Co Coatings by HVOF

A WC-12Co coating prepared by high-velocity oxygen fuel (HVOF) was remelted with a CO₂ laser, and the surface–interface morphologies, plane energy spectrum, and phases of the coating were analyzed by means of field emission scanning electron microscopy (FESEM), energy-dispersive spectrometry (EDS), and X-ray diffraction (XRD), respectively. The friction and wear behaviors of the WC-12Co coating were investigated at high temperature with a wear test, and the morphologies and the changes in chemical elements on the wear scar after the wear test were analyzed with SEM and EDS, respectively. In addition, the influence of high temperature on the coefficient of friction (COF) and wear performance is discussed. The results show that the substrate is closely bonded with the substrate after laser remelting (LR), which includes mechanical bonding accompanied by metallurgical bonding. The average coefficient of friction (COF) at 600, 700, and 800°C is 0.6832, 0.3957, and 0.1922, respectively. The wear mechanisms of WC-12Co coating at 600 and 700°C are adhesive wear, abrasive wear, and oxidative wear, respectively, and the wear mechanism of the coating at 800°C is serious oxidative wear.     

A novel route to fabricate Yb:YAG ceramic fiber and its optical performance

Transparent laser ceramics are the attractive gain medium for solid-state lasers. However, they have not been applied to the fiber lasers due to the difficulty of forming green fibers by traditional methods. In this study, a novel route combined aqueous gelcasting with capillary glass tube was designed to prepare Yb:YAG transparent ceramic fiber with a diameter of 1.0 mm and 43.0 mm in length for the first time. The slurry with high solid loading and low viscosity was smartly inhaled into the capillary glass tube to conquer the difficulty of casting. The green fibers without cracks and deformation had highly dense microstructure. The in-line transmittance of highly doped 15.0 at.% Yb:YAG transparent ceramic disc prepared from the same preparation conditions of Yb:YAG ceramic fiber was 80.0 % at 1064 nm. This study provides a novel route to prepare transparent ceramic fiber differing from extrusion processing, promoting the development of fiber laser.