Diffusion characteristic of sulfate anion in surface region of cement mortar at early stage

The SO_4~(2-)concentration distributions in surface region of cement mortar immersed in sulfate solution at early stage were measured by layered sampling method combined with chemical analysis, and the diffusion coefficients of SO_4~(2-)anions in surface region of mortar into internal area were calculated by means of instantaneous plane diffusion theory. The experimental results showed that the SO_4~(2-)concentration gradually reduced when the diffusion depth increased in the surface region of mortar. Diffusion coefficient(D) was relevant with the concentration and kind of environmental sulfate solution, which reduced with immersion time at the beginning, and then rose slowly after a period of time. The calculation of initial diffusion coefficient(D_0) and starting time of deterioration(t_∞) caused by sulfate attack was further attempted based on the data of diffusion coefficient, and it was found that D_0 and t∞ were all relevant with concentrations of sulfate and different kind of sulfate as well.     

Solidification/Stabilization of Zinc-lead Tailings by Alkali Activated Slag Cement

An appropriate proportion of alkali activated slag cement, abbreviated as AASC later, was determined based on strength test of paste specimens. Results showed that AASC prepared from 14% low modulus water glass and blast furnace slag presented its compressive strength of hardened cement paste of 69.6, 84.0 and 91.8 MPa at 3, 7, and 28 d curing ages respectively. Flowability of the fresh tailings-cement pastes and the strength development of hardened tailings-cement paste were also tested both in the cases with addition of AASC and Portland cement. The fresh tailings-cement paste added with AASC presented much better flowability and the corresponding hardened paste presented higher compressive strength, especially the long term strength, than those added with Portland cement. Therefore, tailings paste added with AASC allowed lager solid content than that of Portland cement in order to keep the similar flowability. SEM observation on the microstructure of the hardened tailings-AASC mixture pastes showed obvious cementation effect. MIP measurements also showed that the total porosity of the hardened tailings-cement pastes decreased, and the portion of larger pore also decreased when the dosage of AASC increased. It is believed that AASC is more suitable to be used as a binder for the stabilization of zinc-lead tailings and for its backfilling operation than Portland cement.     

遥感信息元数据集成服务系统的研究与实现

在SOA框架下研究遥感信息资源元数据的集成涉及的关键技术。系统中数据源以服务的方式动态接入,并通过一个中间代理层对外提供统一的服务;系统将W eb服务技术与联邦模式技术进行有机地结合,实现了异构遥感元数据的集成,支撑遥感数据的跨域共享。试用结果表明,系统完全达到了设计目标,效果良好。     

油田井站单井自动计量系统研究

数字化油田的基本问题之一是建立安全可靠规范的油田井站单井自动计量系统。文章给出了数字化油田的三个基本内涵,结合纯梁采油厂48号井站,设计了油田井站单井自动计量系统。针对井站各井流量范围大小差别很大的特点,开发了复合流量计量技术。按照对单井数据进行综合利用的要求,基于 OPC 协议和 Visual Baisc 语言,开发了单井数据库。该系统投运以来,运行状态良好,达到了设计要求。     

有机玻璃仿水晶像制作

采用铸塑本体聚合法,空气浴生产有机玻璃仿水晶像,其主要生产原料有MMA、BPO以及相片、风景照、明信片、杂志广告页等内嵌物。探讨了生产这种有机玻璃仿水晶像的生产工序及注意事项。实验证明,通过此法可直接生产大而薄、图象清晰、晶莹剔透的密封式有机玻璃仿水晶像。     

低水灰比条件下水泥砂浆的抗硫酸盐侵蚀性能

硫酸盐侵蚀是混凝土耐久性研究的重要组成部分,被认为是引起混凝土材料失效破坏的主要因素之一。研究了低水灰比条件下掺有超细矿渣粉的水泥砂浆在不同种类和浓度的硫酸盐溶液中浸泡后的力学性能变化,同时,对侵蚀试样的孔结构进行了分析。试验结果表明:与普通水灰比相比,低水灰比条件下水泥砂浆的抗硫酸盐侵蚀性能改善更加显著;超细矿渣粉的引入不仅可以增加水泥砂浆的强度,而且可以改善其抗硫酸盐侵蚀性能;同时,矿渣粉掺加改变了水泥硬化体的孔隙率,水泥硬化体趋于致密化。     

折弯辅助机器人的设计及动力学仿真

从自动化折弯工艺出发,设计了B20型六轴直角坐标折弯机器人整机结构,并在多体动力学分析软件中对系统进行建模,完成了运动学仿真,获得了Y、Z、A轴的速度、加速度曲线,为具体的结构设计和运动控制提供依据。     

长江中下游及大连附近部分电厂排灰量及灰质调查

长江中下游及大连附近部分电厂排灰量及灰质调查潘志华执笔（南京化工大学材料科学与工程系粉煤灰调查小组）１９９６年４～９月,我们对长江中下游沿岸和大连附近部分（２２个）火电厂粉煤灰排放情况进行了实地调查,并对各粉煤灰的物理、化学性质和用作水泥混凝土混合...     

有效降低折弯机喉口处应力的机身优化设计

喉口是折弯机机身结构中的薄弱环节,该处应力集中比较严重。本文结合MB8-250×3200数控折弯机新机型研发项目,采用有限元法对机身进行了优化。优化后的机身不但有效地降低了喉口处的应力,而且节约了材料,提高了经济效益。     

水泥熟料-粉煤灰体系中粉煤灰活性的复合激发研究

通过水泥砂浆强度试验方法研究了水泥熟料-粉煤灰体系中添加CaO、Na2SO4、明矾等化学物质对其中的粉煤灰活性的激发效果,同时借助于XRD和SEM分析了水泥硬化浆体的组成和微观结构.研究结果表明:CaO-Na2SO4-明矾复合添加能够很好地激发粉煤灰活性,使粉煤灰水泥早期强度降低程度减小.采用42.5等级硅酸盐水泥熟料,粉煤灰掺量高达50％时水泥强度仍然能够达到42.5等级指标.XRD分析表明,CaO-NaSO4-明矾复合激发剂的加入引起了水泥硬化体样品中石英和Ca(OH)2衍射峰的降低,说明它们在一定程度上促进了水泥水化放出的Ca(OH)2与粉煤灰中酸性氧化物的反应,从而加剧粉煤灰潜在活性的快速释放.水泥硬化体样品的SEM照片显示,CaO-Na2 SO4-明矾的加入,使粉煤灰球体表面腐蚀明显,硬化体结构更加致密化.