Precipitous weakening of quartz at the α–β phase inversion

Crystalline quartz has long been identified as among the weakest of abundant crustal minerals. This weakness is particularly evident around the α–β phase inversion at 573°C, in which Si–O bonds undergo a displacive structural transformation from trigonal to hexagonal symmetry. Here we present data using indentation testing methodologies that highlight the precipitous extent of the transformational weakening. Although the indentations are localized over relatively small specimen contact areas, the data quantify the essential deformation and fracture properties of quartz in a predominantly (but not exclusively) compressive stress field, at temperatures and pressures pertinent to conditions in the earth's crust.     

Effect of partial replacement of geopolymer binder materials on the fresh and mechanical properties: A review

The growth of demand for concrete raises concerns about the consumption of natural resources and ordinary Portland cement. Geopolymer composites show promise as a sustainable alternative for conventional cement concrete. Considering the wide range of potential geopolymer composites applications (including suitability for transportation infrastructure, underwater applications, repair and rehabilitation of structures as well as recent developments in 3D printing), the desired fresh and mechanical properties of the geopolymer composite may vary between applications: for example, rapid setting can be a merit for certain applications and a demerit for others. Therefore, the desired fresh and mechanical properties (e.g., workability, setting time, compressive strength, etc.) can be controlled for a given geopolymer source material through its partial substitution by natural or by-product materials. Recognizing the critical role of various replacement materials in enhancing the potential applications of geopolymer composites, the present review was undertaken to quantify and understand the effect of partial replacement by fly ash, metakaolin, kaolin, red mud, slag, ordinary Portland cement, and silica fume on the setting time, workability, compressive strength and flexural strength of various source materials addressed in the literature. The review also provides insights into research gaps in the field to promote future research.     

内蒙古大青山麻粒岩相糜棱岩石英的变形行为

在内蒙古大青山地区发育一套高温区域变质岩──麻粒岩，在这高温变质岩内有一系列的糜棱岩带．通过对糜棱岩带中石英的研究，对比深部地壳与浅部地壳石英的变形特点，获得一些新的认识．对石英显微构造、动态重结晶、TEM研究及石英岩组学方面进行了研究，发现石英的塑性变形显著，以缎带石英产出，发育各种塑性变形的显微构造，变形带、波状消光和亚颗粒显著：TEM观察到石英中有直线状的位错．岩组学研究显示出石英高温变形和多期构造叠加的特点．     

谐振式力传感器敏感结构的研究

利用材料力学及弹性力学法，对石英晶体谐振式力传感器的悬臂梁结构进行了研究，得出了双梁单岛及三梁单岛悬臂梁结构的力转移系数，在与实验结果进行了比较后证明，支承结构的理论推导与实验结果一致。     

济钢120t转炉二次烟气除尘设计

济钢120t转炉二次烟气除尘设备选用长袋低压脉冲除尘器,风机采用液力偶合器,并设计将加料系统除尘风量直接加入转炉二次烟气除尘系统。系统投产后,每炉钢节电1200kW,烟气排放浓度为47mg/m3,烟气温度在110℃以下。实践证明,该系统具有节能、捕集率高、排放浓度低、自动化程度高等特点。     

硅灰混凝土的研究及其在公路道面的应用

 了提高道路路面混凝土的抗磨能力，采用硅灰代替部分水泥的方法，对硅灰混凝土的性能进行了较系统的试验研究。成果表明其抗压强度、抗弯强度、抗磨强度等指标都得到明显提高，全面达到和超过了规范要求。并已在丹江口水利枢纽上坝公路中得到应用，实践证明硅灰混凝土技术可靠、经济合理、易于施工。特别是抗磨度的提高，对延长公路路面的使用寿命具有重要意义。     

石英砂物料气流冲击粉碎效果影响因素分析

通过对石英砂物料在不同实验条件下的粉碎结果分析，论述了流化床式超细气流粉碎机工艺参数对产品粒度的影响。     

Eight-year exploration of shrinkage in high-performance concrete

In this paper, an experimental and analytical exploration on the effect of water-binder ratio (w/b), silica fume and age on autogenous, carbonation, drying and total shrinkage of high-performance concrete (HPC) is outlined. Eight types of HPC were studied. Carbonation, internal relative humidity (RH) and strength were studied on specimens from the same batch of HPC that was used in the studies of shrinkage. The results indicate fairly good correlation between carbonation, shrinkage, w/b and RH. The type and amount of silica fume affected shrinkage.     

Hydrogen incorporation in Ni–P films prepared by electroless deposition

Electroless NiP films, with 12 to 16 wt % P, were deposited from a moderately acid solution. Thermogravimetric analysis indicates the presence of occluded hydrogen in the layers, which desorbs upon heating. The amount of incorporated hydrogen decreases when the pH of the solution or the nickel sulfate concentration is increased; by contrast it increases with hypophosphite concentration. Cyclic voltammetry, using an electrochemical quartz crystal microbalance, confirms the existence of parasitic reactions, namely the reduction of protons of the solvent during the cathodic process and oxidation of hydrogen during the dissolution of the layers. This behaviour is in qualitative agreement with the proposed reaction scheme.