水工钢闸门主梁模糊失效概率计算方法研究

为合理计算水工钢闸门主梁模糊失效概率,分别将主梁相对变形当作一个随机变量及三个变量的组合,采用积分法、当量随机化方法及蒙特卡罗法进行了计算。当相对变形为一个随机量时,采用积分法及当量随机化方法计算,两者的差别在于积分法用隶属函数描述模糊限值,当量随机化方法是将模糊限值当量作为一个随机量。当相对变形看作三个变量的组合时采用蒙特卡罗法进行计算,该方法考虑了三个变量的分布特性,更符合实际情况,模糊限值也用随机量表示。计算表明,积分法与当量随机化方法结果相近,验证了当量随机化方法的精度;蒙特卡罗法结果与相对变形服从正态分布时、用当量随机化方法计算的结果接近,故主梁相对变形服从正态分布更为合理。三种计算方法中,当量随机化方法计算失效概率相较于其它方法有计算过程简便,效率高的优点。     

基于多维产出ZSG-DEA模型的中国水资源污染综合分配效率测算

利用考虑多维产出的零和收益-数据包络分析(ZSG-DEA)模型测算2000—2017年中国大陆31个省级行政区(以下简称省)在水资源污染排放总量固定下的污染综合分配效率及生产、生活与生态3个维度的产出效率,并基于效率最大化原则对2017年各省污染排放额度进行调整。结果表明:31个省污染综合分配效率的平均值由2000年的0.322上升至2017年的0.364,生产维度产出效率是拉动污染综合分配效率提升的主要动力;2000—2017年31个省污染综合分配效率的平均值为0.341,生态产出过量与生活维度产出不足导致污染综合分配效率处于较低水平;污染综合分配效率、生态维度产出效率与生活维度产出效率受经济发展水平影响较小,而生产维度产出效率受经济发展水平影响较大;污染综合分配效率分布由大到小为东部、西部、中部,生产维度产出效率分布由大到小为东部、中部、西部,生态维度产出效率分布由大到小为西部、中部、东部,生活维度产出效率分布由大到小为西部、东部、中部;各省污染排放调整额度与污染综合分配效率呈正相关关系,北京、天津、上海、浙江、青海与西藏等20个效率较高的省可增加污染排放额度,河北、安徽、河南、江西与湖北等11个效率较低的省需降低污染排放额度。     

基于超声波的围岩松动圈实时监测系统设计

实时地掌握围岩松动圈的范围对矿藏的安全生产具有重要的意义。利用超声波探测的灵活性和准确性,本文提出了一种基于超声波的围岩松动圈监测系统设计方法。此方案利用超声波在岩体中的传播速度与岩体的受力状态和裂隙程度的关系来实时地监测围岩松动圈的情况,具有方便、灵活、易于操作等特点。     

Molybdate and tungstate as corrosion inhibitors for cold rolling steel in hydrochloric acid solution

The inhibition effects of molybdate and tungstate on the corrosion of cold rolling steel (CRS) in hydrochloric acid solution (0.1-0.5 M) were investigated by weight loss and electrochemistry methods. The results reveal that both molybdate and tungstate are very good inhibitors with little concentration. The adsorption of inhibitors on the CRS surface basically obeys the Langmuir adsorption isotherm equation. The effect of temperature on the corrosion behavior of CRS was also studied at 25 °C and 35 °C, the thermodynamic parameters such as adsorption heat (ΔH⁰) and adsorption free energy (ΔG⁰) were calculated. In the same conditions, a comparative study of corrosion inhibition of molybdate and tungstate indicated that molybdate was the better inhibitor in 0.1 M HCl. However, the value of percentage inhibition efficiency (IE) was dependent on the concentration of inhibitors in 0.2-0.5 M HCl. It seemed that molybdate did not have the strong inhibitive effect compared to tungstate with relatively small concentration of inhibitors, but molybdate was a better inhibitor over a wide concentration range of inhibitors. A kinetic study of cold rolling steel in uninhibited and inhibited acid was also discussed. Various parameters such as rate constant k and the kinetic parameter B were calculated for the reactions of corrosion. Polarization curves showed that both molybdate and tungstate are mixed-type inhibitors in acidic media.     

Zirconium-Embedded Polyhedral Oligomeric Silsesquioxane Containing Phosphaphenanthrene-Substituent Group Used as Flame Retardants for Epoxy Resin Composites

A zirconium hybrid polyhedral oligomeric silsesquioxane derivative (Zr–POSS–bisDOPO) is synthesized by the corner-capping and Kabachnik–Fields reactions. It is characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR), and then used as a flame retardant in diglycidyl ether of bisphenol A (DGEBA) to endow epoxy resin (EP) with flame retardancy. The flame retardancy, thermal stability, and mechanical properties of the cured EP/Zr–POSS–bisDOPO composites are investigated. The results show that when Zr–POSS–bisDOPO is added by 5–7 wt%, the EP/Zr–POSS–bisDOPO composites pass the UL-94 V-0 rating test. In addition, they have a better flame-retardant effect than pure EP. The combination of Zr atom embedded in the Si O cubic cage and the two phosphaphenanthrene substituent groups in one corner of cubic cage is expected to realize the Zr/Si/P ternary intramolecular hybrid synergistic effect and achieve the possibility of dispersing metal–POSS cages at a sub-micrometer-scale level into polymer matrix. It also proves that Zr–POSS–bisDOPO produces phosphorus-containing free radicals and terminates the chain reactions in gas phase. Meanwhile the Si O Si and Zr O units are retained in the solid phase, which promote the char formation and enhance the flame retardancy. This kind of Zr-doped POSS will be helpful for developing the new metal–POSS hybrid flame-retardant and polymer composites.     

Ti5Nb人工钉扎中心NbTi超导体的磁通钉扎机制分析

采用棒基组合的装配方法，用热挤压和冷加工相结合的工艺制备了岛状Ti5Nb人工钉扎中心NbTi超导体，其中Ti5Nb体积含量为10％。通过对此超导体进行详细的磁通钉扎机制分析，认为样品的磁通钉扎力特征主要由正常相钉扎和Δκ扎相结合的机制决定。根据分析的结果，采用多源标度方法，很好地拟合了不同线径样品的磁通钉扎力密度随磁场变化的曲线。拟合的结果表明：样品在较低场下的性能主要由正常相钉扎机制决定，而在较高场下的性能主要由Δκ钉扎机制决定。并且随着线径的减小，正常相钉扎力密度和Δκ钉扎力密度均有不同程度的提高。     

适用于扩展有限元裂缝计算的钢筋与混凝土粘结滑移关系

以定量分析钢筋与混凝土粘结滑移关系为目标,利用RCXFEHohai-P扩展有限元程序,计算采用不同粘结滑移公式时钢筋混凝土简支梁的最大裂缝宽度。结果表明,计算所得最大裂缝宽度各不相同,且都与《混凝土结构设计规范》(GB 50010—2010)所列最大裂缝宽度公式计算值存在差别。为此,基于GA-BP神经遗传网络,以规范最大裂缝宽度公式计算值为预测目标,反演得到适用于扩展有限元裂缝计算的粘结滑移公式,算例表明该公式能满足扩展有限元裂缝宽度计算要求。研究成果对提高扩展有限元裂缝分析的准确性具有一定的参考价值。     

观音岩水电站厂房坝段接缝灌浆工艺

观音岩水电站装机容量 3 000 M W, 为一等大( ? ) 型工程。厂房坝段设置 5条横缝, 分为 6 个坝段。通过接缝 灌浆, 极大的改善厂房坝段受力条件, 提高大坝结构整体性和耐久性。结合观音岩水电站现场施工条件, 从施工角 度论述了接缝灌浆的施工工艺以及施工过程中可能存在的问题及处理方法。     

聚天冬氨酸的合成与表征

介绍了以L -天冬氨酸为原料 ,热缩合成聚天冬氨酸酐 ,水解得到聚天冬氨酸的合成工艺。采用凝胶色谱法测定了聚天冬氨酸的分子量 ,并用核磁共振对其进行了表征。     

CpG-ODN对乙肝核酸疫苗及重组疫苗免疫效果的影响

目的研究CpG寡聚脱氧核苷酸(CpGODN)对乙肝核酸疫苗及重组(CHO细胞)疫苗免疫效果的影响。方法核酸疫苗实验组用CpGODN与乙肝核酸疫苗联合免疫BALBc小鼠,阳性对照组注射核酸疫苗,阴性对照组注射质粒pVAX1;重组疫苗分4个实验组,用CpGODN与不同剂量的重组疫苗配伍后分别免疫BALBc小鼠,阳性对照组注射重组疫苗,阴性对照组注射生理盐水。应用ELISA检测小鼠血清中的抗HBs水平。结果CpG与乙肝核酸疫苗组抗体阳转率比阳性对照组提高3倍,抗体水平提高2倍。CpG与重组疫苗组的阳转率和阳转时间均高于或早于CpG与核酸疫苗实验组。加入CpGODN后,即使重组疫苗用量减少3倍,诱导抗体水平和阳转率均无明显改变。结论CpGODN可提高乙肝核酸疫苗和重组疫苗的免疫效果,并使抗体产生的时间提前。