煤矸石制备活性炭-氧化物复合吸附材料及硅铝水处理剂的研究

研究开发了由煤矸石制备活性炭-氧化物复合吸附材料、硅铝水处理剂的清洁生产工艺,即在惰性气体气氛中,焙烧、活化由固体碱调配过的煤矸石原料,使其中的碳转化为活性炭,然后将其通过碱提、酸浸两步法,实现了煤矸石中主要元素的全部利用.讨论了活化、碱提、酸浸和合成硅铝水处理荆过程中各种条件对吸附材料性能的影响.系统研究了材料对淀粉等工业废水的吸附性能,并对该复合材料进行了表征,所制备的吸附材料孔容为1.608 cm3/g,总比表面积为305.63 m2/g,且以中孔为主,适用于淀粉类工业废水的处理.     

高密度电法在灰岩地区勘察中的应用

灰岩地区较为突出的特点就是溶蚀现象较为普遍,会产生较多的溶蚀带、溶洞等不良地质现象,会严重地影响到基础工程质量与施工进度。本文介绍了高密度电法结合其他物探手段对灰岩地区溶洞进行的探测,并根据地震波场特征、面波波速、密实度和电阻率特征,对溶洞进行分类判别。结果证明了高密度电法应用在灰岩地区具有较好的实际效果和应用前景。     

Influences of reinforcement on differential drying shrinkage of concrete

Shrinkage strain of concrete specimen with different reinforcement configuration was measured at various depths from the exposed surface by using several pairs of displacement sensors. Only one surface of the concrete specimen was exposed to dry condition during the experiment. The results show that differential shrinkage strain occurs in both plain and steel reinforced concrete specimens according to depths from the exposed surface. A higher reinforcement ratio results in a greater restraint against shrinkage of concrete nearby reinforcement rebar and a worse differential shrinkage strain distribution in the concrete specimen. The restraint against shrinkage of concrete becomes lower with the increasing distance from reinforcement rebar. Under the same reinforcement arrangement, a higher free shrinkage of concrete leads to a stronger restraint against shrinkage and a higher shrinkage stress formation in local concrete. The relationship between shrinkage strain and reduction of relative humidity in reinforced concrete structure is far different from that in plain concrete.     

连续小波变换在多元函数空问中的应用

使用连续小波变换讨论了某些偏微分方程和相应的积分方程之间的关系．使用连续小波变换能够将这些偏微分方程变换成相应的积分方程，这些偏微分方程与相应的积分方程不仅在弱收敛意义下是等价的，而且在范数收敛意义下也是等价的．     

Synthesis of γ-Al2O3 nanoparticles by chemical precipitation method

Highly pure active γ-Al₂O₃ nanoparticles were synthesized from aluminum nitrate and ammonium carbonate with a little surfactant by chemical precipitation method. The factors affecting the synthesis process were studied. The properties of γ-Al₂O₃ nanoparticles were characterized by DTA, XRD, BET, TEM, laser granularity analysis and impurity content analysis. The results show that the amorphous precursor Al(OH)₃ sols are produced by using 0.1 mol/L Al(NO₃)₃ · 9H₂O and 0.16 mol/L (NH₄)₂CO₃ · H₂O reaction solutions, according to the volume ratio 1.33, adding 0.024% (volume fraction) surfactant PEG600, and reacting at 40 °C, 1 000 r/min stirring rate for 15 min. Then, after stabilizing for 24 h, the precursors were extracted and filtrated by vacuum, washed thoroughly with deionized water and dehydrated ethanol, dried in vacuum at 80°C for 8 h, final calcined at 800 °C for 1 h in the air, and high purity active γ-Al₂O₃ nanoparticles can be prepared with cubic in crystal system, O _H ⁷ -FD3M in space group, about 9 nm in crystal grain size, about 20 nm in particle size and uniform size distribution, 131. 35 m²/g in BET specific surface area, 7 – 11 nm in pore diameter, and not lower than 99.93% in purity. Foundation item: Project(03JJY3015) supported by the Natural Science Foundation of Hunan Province     

结构参数对单层厂房空间工作系数的影响

用文献[2]给出的方法计算了单层厂房的空间工作系数,北分析了柱刚度,屋盖剪切刚度,山墙间距对空间工作系数的影响。计算结果表明空间工作系数随柱刚度,山墙间距的增大而增大,随层盖的剪切刚度的增大而减小。文中还给出了定量的影响曲线。     

纳米SiO2超高强高流态混凝土及改性机理

通过正交试验提出纳米超高强高流态混凝土的胶凝材料配合比设计参数,并研究了纳米SiO₂的掺入对传统掺硅灰、粉煤灰超高强水泥基胶凝材料强度及工作性能的影响。在保证水胶比不变的条件下,开展了混凝土配合比试验,并研究了纳米SiO₂对混凝土抗压强度的影响及其微观机理。结果表明：超高强高流态混凝土中胶凝材料最优比例为：纳米SiO₂：硅灰：粉煤灰：水泥=1：8：20：71;在胶凝材料用量为600~1 000 kg/m³范围内,随着其掺量的增加,混凝土流动度不断增加,抗压强度先增大后减小,当其掺量为800 kg/m³时,抗压强度最大。分析认为,纳米SiO₂、硅灰与粉煤灰形成的三元多尺度堆积体系能优化粉体材料在混凝土中的微集料密实填充效应,纳米SiO₂的二次水化反应也有效改善了硬化水泥石的微观结构,并优化其形态分布,进一步增大其强度。     

倾斜基岩条件下轨道交通振动衰减规律研究

通过模型槽试验和有限元相结合的方法,研究了在倾斜基岩条件下高架轨道交通引起地表振动的衰减规律,分析倾斜角度、荷载频率、桩长对地面环境振动的影响。结果表明：倾斜基岩条件下,地表振动衰减快慢呈现出方向差异化,一般沿基岩倾斜正下方衰减最慢,沿正上方衰减最快,并从正下方到正上方衰减逐渐变快。基岩层倾角越大,地面振动响应越小,基岩倾角变化对地面振动响应的方向差异化影响较为显著。随着荷载频率的增加,地表响应速度先线性增加,然后增速变缓;当频率为13 Hz时,与桩等距离各方向振动响应差异最大。地表速度响应随桩长增加呈线性减小,且距桩越近减小越快;桩长变化对与桩等距离各方向振动响应差异影响并不明显。     

供热系统的"垃圾改造"

为解决目前供热锅炉对环境造成的污染问题,改善空气质量,国家已经决定逐年快速取缔区域性锅炉和分散锅炉.我国面临着工业用热、民用采暖和生活用热量迅速增长的需求,为减少新建供热机组的投资,充分利用原有设备,节约能源,采用垃圾焚烧技术对现有锅炉进行改造,必将具有广阔的发展前景和市场需求.     

修正节点接入导纳潮流算法

针对牛顿–拉夫逊法初值选取不当和PQ分解法受网络RX比例影响造成的计算不收敛问题,提出了一种修正节点接入导纳的潮流算法。理论证明该算法是正确的。算例分析表明,该方法收敛可靠、计算速度快,同时不受RX比例与初值选取的影响。