铝及铝合金涂装前处理的研究现状及展望

涂装前的处理关系到最终产品的质量。重点介绍了铝及铝合金表面无铬磷酸盐化学转化处理、稀土转化处理和有机硅烷化处理的特点及应用情况,并对今后的发展方向进行了展望。     

Novel sol-gel derived calcium phosphate coatings on Mg4Y alloy

Calcium phosphates (CaPs) and silicon containing calcium phosphates (Si-CaPs) coatings on a biodegradable magnesium yttrium alloy (Mg4Y) were prepared by a sol-gel technique to improve the bioactivity of the alloy surface. The experimental results show that thick porous coatings comprised of nano-sized calcium phosphate particles can be prepared by heating the as dip coated substrates at 450 °C. The in vitro degradation results show that the coatings do not alter the degradation kinetics of the substrates significantly and the release of magnesium and yttrium ions at initial time points was very similar for both the coated and bare substrates. The cyto-compatibility studies using MC3T3-E1 osteoblasts show that the coated substrates were more bioactive than the uncoated substrates as the cells begin to grow and form a matrix on the coated substrates more easily than on the bare metal. These preliminary results collectively show the potential of use of sol-gel derived calcium phosphate coatings on magnesium based degradable scaffolds to improve their surface bioactivity.     

深海粘土硫酸浸出液中除铁试验

采用磷酸铁法对深海粘土硫酸浸出液进行除铁试验,考察磷酸用量、终点pH、沉铁温度等因素的影响,并与中和除铁进行对比。结果表明,磷酸铁法除铁最佳条件为:磷酸用量为理论值的1.2倍、除铁温度30℃、终点pH=2.5,除铁率达94.77%,重稀土Y~(3+)损失率仅1.37%,与中和沉淀法相比,除铁效果相近,但Y~(3+)损失率明显降低,且具有反应快、易过滤等优点。     

筒辊式永磁磁选机的研制与应用

通过对石英、长石、红柱石等非金属矿的磁选除铁提纯工艺的试验研究和生产应用,证实该工艺的有效性和实用性,生产成本低,节能环保。该工艺能满足规模化非金属矿除铁提纯工业生产的需要,综合经济效果显著。     

氢气还原合成LiFePO_4的动力学探讨

以H3PO4、Fe2O3和LiOH.H2O为原料,用H2还原合成了橄榄石型LiFePO4材料。采用Rietveld全谱拟合法检测不同温度和时间下LiFePO4的转化率,通过研究其转化率与时间、温度的关系,确定了H2还原合成LiFePO4的反应机理、反应级数和速率常数,并给出了控制步骤的转化温度和各阶段的活化能。根据动力学研究的结果,采用H2气氛低温合成,N2气氛高温生长机制合成了LiFePO4/C复合材料。该材料具有单一的橄榄石结构,颗粒尺寸细小均匀,0.1C倍率下,首次放电容量达152.5 mAh/g,放电效率为95.4%,循环30次后,电池的容量保持率达98.4%。     

熔融制样-X射线荧光光谱法测定磷矿石中主次组分

磷矿石是一种不可再生资源,其伴生组分F等也有较高的利用价值,熔片法处理样品后以X射线荧光光谱法(XRF)测定磷矿石中难挥发组分具有精密度高、准确度好的特点,但组分F在高温条件下易挥发,检出限偏高。文章重点研究了F组分高温挥发特性,建立了熔融制样-X射线荧光光谱仪测定磷矿石中P_2O_5、F、SiO_2、Al_2O_3、Fe_2O_3、MgO、CaO、Na_2O、K_2O、TiO_2、MnO和SrO等12种组分的分析测试方法。通过试验确定的分析条件为:稀释比为1∶15,预氧化温度为700℃,熔样温度为1 050℃,熔样时间为4 min。方法中,F、MgO、K_2O为造岩轻组分,无须基体校正;SrO采用Rhα-c作内标;P_2O_5、SiO_2、Al_2O_3、Fe_2O_3、CaO、Na_2O、TiO_2和MnO组分采用理论系数法校正基体效应。方法检出限在0.000 2%~0.042%之间,特别是F组分的检出限可达到0.042%。以GBW07210和GBW07212为对象考察方法精密度,各组分测定结果的相对标准偏差(RSD,n=12)在0.07%~5.1%之间;采用实验方法分析磷矿石标国家标样,及由标准样品合成的样品,测定值与认定值或理论值吻合良好。     

汽水分离效果差的汽包炉炉水处理工况探讨

托电#1机严重积盐之后,在#2机组大修前的半年里将炉水的低磷酸盐处理工况改为AVT(O)工况,使得蒸汽携带至汽机的盐分大大减少,叶片上的积盐减少、剥离,所以#2机大修时的积盐量明显小于#1机;但#2机低压叶片和隔板的腐蚀比#1机严重,通过向炉水中加入适量氢氧化钠,提高蒸汽携带至汽机的盐分中碱性成分所占的比例,从而抑制了氯离子对汽机的腐蚀。     

Isolation of recombinant antibody fragments (scFv) by phage display technology for detection of almond allergens in food products

Tree nut allergies are considered an important health issue in developed countries. To comply with the regulations on food labeling, reliable allergen detection methods are required. In this work we isolated almond-specific recombinant antibody fragments (scFv) from a commercial phage display library bypassing the use of live animals, hence being consistent with the latest policies on animal welfare. To this end an iterative selection procedure employing the Tomlinson I phage display library and a crude almond protein extract was carried out. Two different almond-specific scFv (named PD1F6 and PD2C9) were isolated after two rounds of biopanning, and an indirect phage ELISA was implemented to detect the presence of almond protein in foodstuffs. The isolated scFvs demonstrated to be highly specific and allowed detection of 40 ng mL⁻¹ and 100 ng mL⁻¹ of raw and roasted almond protein, respectively. The practical detection limit of the assay in almond spiked food products was 0.1 mg g⁻¹ (110–120 ppm). The developed indirect phage ELISA was validated by analysis of 92 commercial food products, showing good correlation with the results obtained by a previously developed real-time PCR method for the detection of almond in foodstuffs. The selected phage clones can be affinity maturated to improve their sensitivity and genetically engineered to be employed in different assay formats.     

金属氯化物催化磷酸三丁酯的合成研究

以金属氯化物作催化剂,以丁醇和三氯氧磷为原料合成了磷酸三丁酯。对催化反应机理进行了探讨,考察了催化剂的种类及用量、反应时间、反应温度和原料摩尔比等因素对反应的影响。结果表明:金属氯化物可与丁醇原位反应生成金属酸丁酯,从而起到催化作用。当三氯化铝用量为三氯氧磷物质的量的7.6%,反应时间4h,反应温度30℃,丁醇与三氯氧磷摩尔比4∶1时产物收率可达85.1%,产品纯度99.4%。     

微反应器内自热结晶法制备磷酸二氢铵

为制备高纯固体磷酸二氢铵(MAP)并降低过程能耗,本工作提出一种基于微反应器的新工艺——自热结晶法。通过对该过程中放热、汽化、通道内结晶等现象的研究,更清楚地认识了微反应器内自热结晶法制备MAP的过程规律,为微反应器的设计及最佳工艺的选择提供了基础参数与理论支持。在酸碱物质的量比为1:1,MAP预设质量浓度为33.2%~55.0%时,获得了约40%的结晶收率,且所得样品晶粒小、纯度较高。实验证明,该方法在有效降低能耗的同时保证了较高的产率,具有良好的工业应用价值。