利用蓄电池废硫酸和硼泥制备高品质氢氧化镁

利用废铅酸蓄电池中的废硫酸作为浸取剂,对硼泥中的镁进行回收并制备出高品质的氢氧化镁产品。实验得出了酸浸硼泥的最佳工艺条件：酸浸温度为80℃;酸浸时间为30 min;酸用量为硫酸与硼泥质量比为1.2∶1。利用不同金属水解pH的不同,将酸浸过程中从硼泥和废硫酸中引入的杂质依次去除,得到精制硫酸镁溶液。由精制硫酸镁制取氢氧化镁的工艺条件为：常温下,沉淀剂为氨水,反应终点pH为11,反应时间为2 h,反应物在50℃下陈化12 h,过滤、洗涤后105℃烘干。实验考察了不同沉淀剂对氢氧化镁形貌的影响。所得氢氧化镁纯度在97%以上,粒径在0.1～1μm之间,各项指标均优于中国化工行业标准。     

Fabrication of High-Curie-Point Barium-Lead Titanate PTCR Ceramics

High-Curie-point semiconducting barium-lead titanate positive temperature coefficient of resistivity (PTCR) ceramics of composition Ba_0.897Pb_0.1La_0.003TiO₃ and Ba_0.5Pb_0.5La_0.003TiO₃ were prepared. The starting powders were synthesized by reacting commercial BaTiO₃, PbO, and TiO₂. To avoid the nonstoichiometry due to the volatilization of Pb during the sintering process, a lead atmosphere sintering approach with PbTiO₃ as packing powder was used. The samples being fabricated by this method show a PTCR effect of 3 to 4.5 orders of magnitude above the Curie point. The curie points were about 180°C for Ba_0.897Pb_0.1La_0.003TiO₃ and about 360°C for Ba_0.497Pb_0.5La_0.003TiO₃.     

选择性螯合滴定法测定电镀液中的锡铜铅

提出了测定电镀液中锡铜铅的一个简易快速螯合滴定法.用EDTA螯合锡(Ⅳ)、铜(Ⅱ)、铅(Ⅱ)和其它金属离子,然后分别用三羟基苯甲酸、巯基丁二酸和氨荒丙酸解蔽.释放出的EDTA,用锌标准溶液反滴定(XO-CPB为混合指示剂).终点变化相当敏锐.研究了测定锡、铜、铅时一般共存离子的干扰.此法已被成功地用于测定锡-铜-铅合金电镀液和镀层锡铜铅合金中的锡、铜和铅.     

Use of Re(C5H7O2) in preparation of catalysts for olefin metathesis

New catalysts for olefin metathesis are obtained upon interaction between rhenium trisacetylacetonate and -Al₂O₃ surface. After high temperature treatment in flows of O₂ and N₂ and addition of organometallic compound as a cocatalyst the activity of the resulting catalyst exceeds that of known Re/Al₂O₃ catalysts prepared by impregnation. The catalysts exhibit maximal activity at a cocatalyst surface concentration of 3 × 10^–7 mol/m². Further increase of the cocatalyst concentration leads to deactivation.     

添加剂对镀锡引线可焊性的影响

分析了镀暗锡和光亮镀锡引线的可焊性，讨论了添加剂对镀锡引线可焊性的影响，适量的添加剂能提高引线的平整性和可焊性，获得了具有良好可焊性所需的最佳添加剂的加入量。     

Simultaneous recovery of Pb and PbO2 from battery plant effluents. Part II

Results are reported of experiments and modelling of cathodic Pb and anodic PbO₂ electrodeposition, aimed at developing a process using both reactions simultaneously for treating aqueous effluents from lead–acid battery recycling plants. Pb(II) solubilities and equilibrium potentials were calculated as functions of pH and sulfate activities. Using kinetic parameters from the literature or determined experimentally, models were developed for current density–potential and current efficiency–potential relationships, together with the current density dependence of specific electrical energy consumptions for Pb(II) recovery. Experimental current density–potential and charge efficiency–potential relationships were in broad agreement with model predictions, with near unity current efficiencies for mass transport controlled PbO₂ deposition from electrolytes containing 1 mol Pb(II) m^–3 at pH 12. However, charge efficiencies for cathodic deposition of lead were typically 0.2 for 1 mol Pb(II) m^–3 + 1 mol O₂ (aq) m^–3; removal of dissolved oxygen was predicted and determined to increase current efficiencies to near unity. Pb(II) concentrations were depleted to <60 ppb in a batch recycle reactor system with graphite felt anodes and graphite or titanium felt cathodes. Simultaneous cathodic Pb and anodic PbO₂ electrodeposition resulted in more rapid Pb(II) depletion than for either reaction separately.     

Crack–Tip Toughness of a Soft Lead Zirconate Titanate

Crack–opening displacement (COD) measurements were performed on a commercial lead zirconate titanate (PZT). The intrinsic fracture toughness (or crack–tip toughness) of this material was determined using a new evaluation procedure, which takes into account the near–tip CODs and complete crack profile CODs. The crack–tip toughness K _I0 was determined from an extrapolation of COD data obtained at various loading stages, thus avoiding the complications caused by subcritical crack growth in PZT. Results for plane strain and plane stress condition are presented.     

新型钢铅组合耗能器性能试验及参数优选

为了考察新型钢铅组合耗能器(NCSLD)的力学性能和提高其耗能能力,利用电液伺服压剪试验机对NCSLD耗能器进行力学性能试验,采用ANSYS实体建模的方法对耗能器进行大量的数值分析,并对性能试验和数值分析的结果进行对比,研究耗能器的滞回特征参数与其6个几何参数之间的关系,回归出二者之间的公式.提出评价耗能器性能优劣的标准及其附加条件,并以此标准为依据,利用均匀设计法和遗传算法分别对耗能器的6个几何参数进行优选.结果表明遗传算法的选优效果要好于均匀设计法,同时得到一系列性能良好的NCSLD耗能器.     

Parameter fitting of constitutive model and FEM analysis of solder joint thermal cycle reliability for lead-free solder Sn-3.5Ag

The experimental tests of tensile for lead-free solder Sn-3.5Ag were performed for the general work temperatures range from 11 to 90 °C and strain rate range from 5×10⁻⁵ to 2×10⁻² s⁻¹, and its stress—strain curves were compared to those of solder Sn-37Pb. The parameters in Anand model for solder Sn-3.5Ag were fitted based on experimental data and nonlinear fitting method, and its validity was checked by means of experimental data. Furthermore, the Anand model was used in the FEM analysis to evaluate solder joint thermal cycle reliability. The results show that solder Sn-3.5Ag has a better creep resistance than solder Sn-37Pb. The maximum stress is located at the upper right corner of the outmost solder joint from the symmetric center, and thermal fatigue life is predicted to be 3.796×10⁴ cycles under the calculated conditions. Foundation item: Project(50376076) supported by the National Natural Science Foundation of China     

恒温消化原子荧光法测定面粉中的痕量铅

研究了恒温消化发生原子荧光恒温消化法测量面粉中的痕量铅含量,采用DTD-30恒温消解仪于90℃预消解35 min,180℃消化35 min除去残酸。采用AFS-230E型双道原子荧光光度计,采用氢化物—原子荧光法测定面粉中的铅含量,实验确定了最佳测定条件。该法测定面粉中铅含量的相对标准偏差RSD为1.35%（n=9）,检出限为0.1 ng/mL。铅的线性范围为0～30 ng/mL,相关系数大于0.998。加标回收率为106.92%。