煤矸石掺量和细度对水泥凝结时间的影响

将不同掺量、不同细度的煤矸石与普通硅酸盐水泥混合，得到具有不同颗粒群特征及其性能的水泥——煤矸石试样，研究了煤矸石掺量、细度与水泥凝结时间等性能之间的相互关系。试验结果表明，煤矸石对水泥凝结时间有很显著的延缓作用，并且其延缓程度随煤矸石掺量的增加而增大，而煤矸石的细度对水泥凝结时间的影响不明显。     

论城市的防洪问题

我国是一个水灾频繁的国家,许多城市都受到洪水的威胁。做好城市防洪工作,不仅是水利建设的一项重要任务,而且也是城市建设和城市管理中不可忽视的一个重要方面。城市是全国各地政治、经济、文化和交通的中心,人口密集,防洪的安全,事关重大。     

水能造福 亦能致祸 慎之慎之!——一九八三年汛期丹江口调度严重失误的教训

汉江中游的丹江口水利枢纽是一座以防洪为主,同时具有发电、灌溉和航运等综合效益的大型水利工程。据统计,自1968年下闸蓄水至1993年底的26年间,丹江口水利枢纽已拦蓄入库洪峰流量大于10000立方米每秒的洪水共计63次,发电924亿千瓦时,为江汉平原防洪安全和华中地区电力供应作出了突出贡献,发挥了巨大的防洪效益和经济效益。丹江口水利枢纽管理局已晋升为我国特大型企业。这些都是丹江口水利枢纽管理局广大职工在局党委领导下辛勤劳动的结果,也是水利行业的光荣。     

发展散装水泥与预拌混凝土改善人类居住环境

本文从节约资源能源、减少大气粉尘污染、强化城镇卫生环境、减少噪声污染和下水堵塞等方面,论述了发展散装水泥,对改善人类生态居住环境的意义。     

试论非工程性防洪措施

我国在历史上是一个洪涝灾害频繁的国家。建国以来,在党中央和国务院的领导下,经过各级党委、政府和广大群众的努力,整修新修堤防、圩垸、海塘;修建水库、塘坝、水闸;疏浚开挖排水河道。从而提高了各大江河的防洪能力,初步控制了普通的洪涝灾害,基本上保障了工农业     

纳米γ-Al2O3/PVDF中空纤维膜的结构研究

本文介绍了在聚偏氟乙烯铸膜液中添加无机纳米Al2O3粒子,采用干-湿法纺丝制备γ-Al2O3中空纤维膜的方法.对纳米γ-Al2O3的分散性能的研究发现,在添加剂含量为4%的情况下粒子在二甲基甲酰胺(DMF)体系中的沉降性能最好.并使用电镜对膜的微观结构进行了分析,初步研究了无机粒子在膜孔形成的过程中所起的作用和机理.并且对膜的孔隙率、最大孔径、力学性能和截留率进行了表征.结果表明膜的孔性能、分离性能及力学性能都有一定的改善.孔隙率在提高的同时,其最大孔径相应变小,对牛血清白蛋白的截留率从25.11%提高到67.20%.最大应力和断裂应力分别从3.35N/mm2和3.09N/mm2提高到3.58N/mm2和3.41N/mm2.     

Synthesis of modified D401 chelating resin and its adsorption properties for Pb^2＋

A novel chelating resin with sulfonic group was synthesized by chemical modification of D401 resin with sulphonation reaction and characterized by FT-IR spectrometry. The adsorption properties of the novel chelating resin for Pb²⁺ were studied by batch adsorption, and the adsorption process was analyzed from thermodynamics and kinetics aspects. The adsorption mechanism of Pb²⁺ on the modified D401 chelating resin was discussed by FT-IR spectrometry. Experimental results show that in the Pb²⁺ concentration range of 200–400 mg/L, the adsorption capacities of the modified D401 chelating resin for Pb²⁺ increase by 77%–129%, and Langmuir isothermal adsorption model is more suitable for the equilibrium adsorption data. Adsorption is an endothermic process that runs spontaneously. Kinetic analysis shows that the adsorption rate is mainly governed by liquid film diffusion. The best pH value under adsorption condition is 4–5. The saturated resin can be regenerated by 3 mol/L nitric acid, and the adsorption capacity remains stable after five consecutive adsorption-desorption cycles. The maximal static saturated adsorption capacity of the resin is 206 mg/g at 333 K in the Pb²⁺ concentration range of 200–400 mg/L. The modified D401 chelating resin is an efficient adsorbent for the removal of Pb²⁺ from its single-metal ion solution. Foundation item: Project(708049) supported by the Important Item Cultivation Foundation of Scientific Innovation Project of Colleges and Universities of China