Impact of Yb3+/Er3+ions on crystallization of phosphosilicate glass melts

Transparent glass ceramics were prepared from the phosphosilicate system by melt-quenching devitrification(MQD) method, i.e., nanocrystals spontaneously form during cooling of the melts. Introduction of 2.5 wt.% Yb2O3 and 0.5 wt.% Er2O3 into the glass melt induced the change of type and concentration of crystals. The comparison of rheological and thermodynamic properties of both undoped and Yb3+/Er3+ doped melts showed that addition of Yb3+/Er3+ oxides caused increase of liquid fragility, and degree of medium-range order. In addition, the thermodynamic barriers for nucleation ΔG* as a function of reduced temperature T/Tm were calculated with an assumption of wetting angle θ=90o, Yb3+/Er3+ doped melt tended to firstly nucleate as compared to undoped melt at small undercooling.     

王庄煤矿极薄煤层水力开采技术

针对淄博矿区极薄煤层多,煤质好的特点,通过充分调研,提出了水力机械化开采极薄煤层的方案设想,并从工艺布置、投资、成本及效益等方面进行了可行性分析。     

气相色谱法检测人工真皮皮耐克中环氧乙烷残留量

目的:建立顶空气相色谱法测定人工真皮中环氧乙烷残留的检测方法。方法:采用顶空气相色谱法,色谱柱为石英毛细管柱DB-624(30m×0.32mm×1.8μm),载气为N_2,流速为2.0mL·min~(-1),检测器为FID,检测器温度为200℃,进样口温度为140℃,采用程序升温的方法进行检测。结果:环氧乙烷在0.128～25.6μg·m L~(-1)范围内线性关系良好(r=0.9999),回收率介于97.1%～106.7%,重复性RSD值为1.92%,精密度峰面积RSD值为0.91%,保留时间RSD为0.11%。结论:GC法测定环氧乙烷的残留量,方法灵敏度高,准确可靠,可用于人工真皮皮耐克中环氧乙烷含量的测定     

高水膨胀材料条带充填开采研究

详细介绍了高水膨胀材料的特性及应用效果。根据王庄煤矿五采区的地质采矿条件,结合关键层理论,提出了条带充填开采方案,并进行了相关参数的设计,确定充填步距和充留宽度。分别设计了面积充满率为52%,62%和73%三种方案,地表移动计算结果表明:三种方案地表下沉均控制在200mm以内,水平变形控制在1mm/m以内,通过采用高水膨胀材料条带充填能有效控制地表移动和变形,保护地表建(构)筑物。     

硅对蠕墨铸铁热分析特征值及蠕化率的影响

试验设计了5种不同硅含量的蠕墨铸铁铁液,分析了硅含量对蠕墨铸铁凝固的热分析曲线特征值TEU、TER、△Tr和蠕墨铸铁蠕化率的影响。试验结果表明:(1)在本次试验的硅含量范围内,蠕墨铸铁热分析曲线的特征值TEU和TER先是随着硅的增加而上升,然后,变化不明显;(2)蠕墨铸铁共晶温度回升特征值△Tr随着硅含量的增加呈下降趋势;(3)随着硅含量的提高,蠕墨铸铁中蠕虫状石墨数量减少,球状石墨数量增多,蠕化率降低。     

矿井采空区瓦斯抽放

介绍矿井瓦斯生成、性质及生存状态,研究矿井瓦斯分类及抽放方法     

金刚石的高温化学稳定性研究

金刚石的高温化学稳定性直接影响着陶瓷结合剂的耐火度和陶瓷结合剂金刚石制品的使用寿命。通过研究不同品级的金刚石在不同烧成条件下金刚石晶体的烧失量变化，结果表明：①相同条件下，金刚石品级越高，烧失量越小；裸烧时温度越高，烧失量越大，当温度达到1073K时发生明显的化学反应，达到1173K时，热腐蚀较大。②当通入氩气作保护气时，到1173K才开始发生明显的化学反应。③而埋砂烧成（陶瓷结合剂金刚石试块中）的金刚石与裸烧后金刚石的晶体腐蚀情况相比，埋砂烧成的金刚石晶体耐热腐蚀性好，当温度高于1073K时，埋砂条件下金刚石的抗冲击强度比在同等温度、同等烧成气氛下裸烧金刚石要高出大约30～40％，因此在试验温度范围内陶瓷结合剂不会加速金刚石晶体的氧化腐蚀。     

封接用Li2O—ZnO—Al2O3-SiO2玻璃析晶和热膨胀行为研究

以传统熔融冷却法制得了Li2O-ZnO-Al2O3-SiO2(LZAS)系统无色透明的基础玻璃,通过热处理获得了与4J 29可伐合金封接用微晶玻璃材料.运用DTA、XRD等手段分析了组成和热处理制度对玻璃析晶和热膨胀行为的影响.结果表明,随ZnO取代(SiO2+Al2O3),NBO/T逐渐增大,第1、第3放热峰向低温方向偏移,第2放热峰则稍向高温方向偏移;对于24.5Li2O-15ZnO-8.55Al2O3-51.25SiO2-0.7P2O5系统玻璃来说,晶化温度对析出晶相的种类和含量影响显著,随晶化温度的升高,晶相变化表现出如下趋势:主晶相由方石英向Li2Al2Si3O10转变,次晶相由βⅡ/-Li2ZnSiO4向γ0-Li2ZnSiO4转变.这种变化也反映在热膨胀行为上,即随晶化温度升高,热膨胀系数在(40.2～123.6)×10-7/K之间变化.经535℃, 2h和700℃, 2h处理后获得的热膨胀系数为49.5×10-7/K,可满足与4J 29可伐合金封接使用要求.     

Effects of heat treatment temperature on crystallization and thermal expansion coefficient of Li_2O-Al_2O_3-SiO_2

The basic glass of Li2 O-Al2 O3-SiO2 system using P2O5 as nucleator was prepared by means of conventional melt quenching technology, and the heat-treatment process was determined by using differential thermal analysis. The crystalline phases and the microstructure of the glass-ceramics were investigated by using X-ray diffraction and scanning electron microscopy. The results show that the glass based on Li2 O-Al2 O3-SiO2 oxides using P2 O5 as nucleator can be prepared at lower melt temperature of 1 450 ℃ and the glass-ceramics with lower thermal expansion coefficient of 21.6 × 10-7 ℃ 1 can also be obtained at 750 ℃. The glass-ceramics contain a few crystal phases in which the main crystal phase is β-quartz solid solution and the second crystal phase is β-spodumene solid solution. When the heat treatment temperature is not higher than 650 ℃, the transparent glass-ceramics containing β-quartzsolid solution can be prepared. β-quartz solid solution changes into β-spodumene solid solution at about 750 ℃. And the appearance of the glass-ceramics changes from translucent, part opaque to complete opaque with increasing temperature.     

玻璃粘度与温度关系研究发展现状

本文综述了玻璃粘度与温度关系的描述方法,介绍了各个公式的优缺点。虽然John C.Mauroa,Yuanzheng Yue等人在提出的Mauro-Yue公式跟VFT公式、AG和AV公式一样都有三个参量,但是该公式克服了VFT公式和AV公式在低温下存在很大的系统误差的问题,而且对有机物和无机物液体的粘温关系都可以描述。