拱坝表孔泄流下游消能防冲形式的试验研究

摘 要：针对中型拱坝下游消能防冲形式的选择问题,通过物理模型试验,对比分析了长护坦防护、水垫塘+二道坝和短护坦先冲后护三种布置形式下相应的水力学指标。试验结果表明：长护坦方案时,水垫塘内水流流态较差,底板和护岸易失稳破坏;水垫塘+二道坝方案时,水流流态和各项水力学指标满足要求,但水垫塘和二道坝的造价较高;短护坦先冲后护方案时,冲坑位置及深度均在允许范围内,该方案的应用会受到拱坝下游地质条件的制约。依据短护坦先冲后护的试验成果,提出初步确定短护坦防护范围的方法。本工程下泄的单宽流量较小,根据试验成果及类似工程经验,并结合坝址地质和工程造价因素,推荐消能工布置方案为“短护坦先冲后护”方式。     

New synthesised pyridazine derivatives as effective inhibitors for the corrosion of pure iron in HCl medium

The inhibition of pure iron in 1 M HCl by new synthesised pyridazine compounds has been studied by weight loss, electrochemical polarisation and electrochemical impedance spectroscopy (EIS) measurements. The results obtained reveal that these compounds are efficient inhibitors. The inhibition efficiency increases with the increase of inhibitor concentration and reached 98% at 10⁻⁴ M for 5-benzyl-6-methyl pyridazine-3-thione. Potentiodynamic polarisation studies clearly reveal that the presence of pyridazines does not change the mechanism of hydrogen evolution and that they act essentially as cathodic inhibitors. The temperature effect on the corrosion behaviour of pure iron in 1 M HCl without and with the pyridazines at 10⁻⁴ M was studied in the temperature range from 298 to 353 K. EIS measurements show that the increase of the transfer resistance with the inhibitor concentration.     

Φ10007/00有压三产品重介旋流器结构参数优选与分选效果

辛置选煤厂针对原煤煤质变化后的特点 ,采用有压给料三产品重介旋流器为核心的高效选煤工艺系统分选 5 0～ 0mm原煤 ;对旋流器一段及二段中心管的直径和插入深度、二段底流口的直径等进行了优化调整 ,同时调整了介质泵的工作频率及悬浮液密度等参数 ,取得了分选效率高、产品质量稳定等显著效果     

氨纶干法纺丝介质循环系统的设备和工艺介绍

介绍氨纶干法纺丝技术中纺丝介质 (SM )循环系统的主要设备 ,对循环风压力、风温度和风量控制进行了探讨。严格控制SM循环工艺参数 ,可减少并丝现象。     

SO_4~(2-)-TiO_2/Al_2O_3固体超强酸催化合成苹果酯-A和苹果酯-B的研究

通过浸渍法制备了SO42--TiO2/Al2O3固体超强酸催化剂,用Hammett指示剂法测定了其酸强度;以乙酰乙酸乙酯和乙二醇、1,2-丙二醇为原料,合成了苹果酯-A和苹果酯-B,考察了催化剂的焙烧温度、TiO2的负载量、反应温度、反应物配比、催化剂用量等因素对反应的影响以及催化剂的重复使用性。结果表明,在425～575℃温度范围内,SO42--TiO2/Al2O3体系可以形成超强酸;在苹果酯-A和苹果酯-B合成中具有催化活性高、催化速率快、化学稳定性好,重复使用性佳、无环境污染;在最佳条件下,苹果酯-A和苹果酯-B的收率分别可达89.3％和91.5％,质量分数为97％～99％。     

中压汽包法兰断裂失效原因分析及改进措施

本文针对中压汽包法兰断裂失效原因进行分析，指出汽包上两个法兰同时断裂的原因在于安全阀排汽管路设计上的失误，并提出对安全阀排汽系统的改进措施。     

Marvelous self-assembly of hierarchically nanostructured porous zirconium phosphate solid acids with high thermal stability

A hierarchical structure of thermally stable macroporous zirconium phosphate solid acids with supermicroporous walls was prepared by a simple self-assembly process from the precursors of zirconium propoxide and orthophosphoric acid solution. The macroporous structures are uniform with the diameters ranging from 300 to 800 nm, one-dimensional channel-like. The effect of surfactant Brij 56 on the formation of macroporous structures has been studied. The frameworks of the synthesized hierarchical zirconium phosphates are amorphous with Zr–O–P bonding, exhibiting remarkably high thermal stability (at least 800 °C), on the basis of the X-ray diffraction (XRD), N₂ adsorption, X-ray photoelectron spectroscopy (XPS) analysis, Fourier transform infrared (FT-IR) and ³¹P nuclear magnetic resonance (NMR) spectra. Larger quantities of Zr–OH and P–OH groups are observed besides surface hydroxyl groups, suggesting the presence of acidity and the possibility of surface functionalization for practical applications including catalysis. The macroporous zirconium phosphates with hierarchical structures could also be the potential and efficient catalyst supports for the design of the structured catalysts and reactors.     

盐水介质铝合金复合缓蚀剂的研究

以葡萄糖酸盐、醇胺磷酸酯、苯并三氮唑(BTA)、表面活性剂、添加剂等合成了盐水介质铝缓蚀剂并用腐蚀失重法进行了评价。在22.5％盐水介质中,葡萄糖酸钙:苯并三氮唑:硫酸锌:醇胺磷酸酯:十二烷基苯磺酸钠=1.0:1.0:0.6:0.2:0.05,50℃时,铝缓蚀率可达95％以上。     

Numerical study of the transfer of shock-wave loading to a screened flat wall through a layer of a powdered medium and a subsequent air gap

The two-velocity, two-temperature model with two stresses in a mixture of a gas and solid particles contacting each other is used to numerically study the dynamic effect of an air shock wave incoming onto a solid wall with a screening layer of a porous powdered medium at some distance from the wall. The process is described for the case of one-dimensional planar motion of the gaseous and disperse phases under the assumption of a viscoelastic behavior of the powder skeleton. The effect of stepwise shock waves onto the porous powdered screen is considered. The influence of parameters of the screening layer and the air gap on the dynamics of loading of the screened solid wall is analyzed. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 1, pp. 132–142, January–February, 2007.     

考虑边界反射的河流离岸排放污染混合区计算方法

在等强度点源离岸排放条件下,从简化二维移流扩散方程的解析解出发,探讨了考虑两岸反射作用的中宽河流污染混合区的计算方法。给出了污染混合区边界形状曲线与量纲一方程的形式;采用迭代计算和试算比较法,给出了靠岸与离岸两种类型混合区各几何特征参数(坐标)、面积及面积系数与相对离岸距离的关系曲线,提出了以相对离岸距离a'作为判据的排放类型分区条件。给出了河流岸边、离岸与中心排放的分类判别准则:(1)当0≤a'≤a'1时,简化为岸边(近岸)排放类型;(2)当a'1a'a'2时,称为离岸排放类型;(3)当a'2≤a'≤0.5时,简化为中心排放类型,并给出了岸边排放类型与离岸排放类型的临界相对离岸距离a'1和中心排放类型与离岸排放类型的临界相对离岸距离a'2的表达式。通过回归分析,给出了中宽河流离岸排放类型混合区主要特征参数的实用计算公式,可作为中宽河流污染混合区范围计算和排污口位置优化设计的依据。