FAAS法测定大气降水中的k+、Na+、Ca2+和Mg2+

本文应用FAAS法直接测定大气降水中阳离子K+、Na+、Ca2+、Mg2+。通过对火焰状态的选择,以减少和抑制电离的干扰。方法简便、快速、准确。加标回收率在94.0%-105.2%之间,RSD<5.07%。     

Diffusion of NaCl in meat studied by (1)H and (23)Na magnetic resonance imaging

The effect of sodium chloride (NaCl) diffusion into meat was investigated. Proton and sodium magnetic resonance imaging were used to determine the diffusion behaviour of brine (NaCl) in porcine Longissimus dorsi and semitendinosus. NaCl diffusion was visualized through images and diffusion coefficients were determined to be in the range 3-7×10(-10)m(2)s(-1), which is in agreement with values reported in the literature. The diffusion coefficient was found to increase during curing, suggesting microstructural changes in the meat. A supplementary experiment proved that the diffusion behaviour of sodium chloride in regions of meat with connective tissue/fat is distinctive from regions with pure myofilament tissue, as anticipated. Apparent diffusion coefficient (ADC) maps showed that meat microstructures shrunk when cured with 20% (w/w) NaCl brine. ADC across (⊥) the main muscle fiber direction decreased more than ADC along (‖) the main muscle fiber direction. The greater shrinkage in the direction across muscle fibers suggests that the curing induced shrinkage of the transverse structures rather than reduction in longitudinal structures.     

Bi0.5Na0.5TiO3基A位多重复合无铅压电陶瓷的研制

针对钛酸铋钠(Bi0．5Na0．5TiO3)基复合钙钛矿压电铁电材料,发明了多种新的AB03型A位多重复合无铅压电陶瓷体系。这些新的无铅压电陶瓷具有压电铁电性能优良、铁电电滞回线矩形度高、压电铁电性能的温度特性好、工艺稳定性和重复性好等特点。所测得的一个体系(Bi0．5(Na1-x-yKxLiy)0．5TiO3)的d33达230pC／N,其kp达0．40,Pr达40μC/cm^2,矫顽场Ec则较低(小于4kV／mm);变温铁电电滞回线测试表明,在温度接近200℃时,该陶瓷还具有很好的铁电电滞回线。该体系无铅压电陶瓷性能优异,工艺性好,具有实用性。     

玉米Na+/H+反向转运器编码基因ZmNHX的克隆及其表达特性分析

植物液泡膜Na^ ／H^ 反向转运器在植物耐盐性方面发挥着重要的作用。根据序列同源性比较分析结果,利用RACE技术获得了一个与水稻Na^ ／H^ 反向转运器基因OsNHX1具有高度序列同源性的玉米Na^ ／H^ 反向转运器基因(命名为ZmNHX)的全长mRNA序列。对正常及胁迫条件下的玉米幼苗进行Northern blot分析发现,ZmNHX基因的表达受NaCl、LiCl、甘露醇和ABA诱导。玉米ZmNHX在盐胁迫适应过程中可能起着非常重要的作用。     

TiF3 catalyzed MgH2 as a Li/Na ion battery anode

MgH₂ has been considered as a potential anode material for Li ion batteries due to its low cost and high theoretical capacity. However, it suffers from low electronic conductivity and slow kinetics for hydrogen sorption at room temperature that results in poor reversibility, cycling stability and rate capability for Li ion storage. This work presents a MgH₂–TiF₃@CNT based Li ion battery anode manufactured via a conventional slurry based method. Working with a liquid electrolyte at room temperature, it achieves a high capacity retention of 543 mAh g^?1 in 70 cycles at 0.2 C and an improved rate capability, thanks to the improved hydrogen sorption kinetics with the presence of catalytic TiF₃. Meanwhile, the first realization of Na ion uptake in MgH₂ has been evidenced in experiments.     

锂离子电池Na_2Li_2Ti_6O_(14)负极材料的合成与电化学性能

采用高温固相法成功合成了新型钛基负极材料Na_2Li_2Ti_6O_(14),并研究了其结构及电化学性能。利用高分辨透明电镜(HRTEM)、X射线衍射(XRD)及其Rietveld精修、扫描电子显微镜(SEM)及能谱分析(EDS)表征分析了材料的物相和显微结构。结果表明,合成的Na_2Li_2Ti_6O_(14)负极材料为纯相,具有Fmmm空间群结构;Na_2Li_2Ti_6O_(14)颗粒约为500~800 nm,Na、Ti和O三种元素分布均匀。循环伏安(CV)、充放电及电化学阻抗谱(EIS)测试表明,材料具有较好的锂离子脱嵌可逆性,较好的倍率性能和循环稳定性。钛电流密度为500 m A/g充放电时,Na_2Li_2Ti_6O_(14)材料的首次脱锂(充电)容量为180 m A·h/g,100次循环后可逆容量为136 m A·h/g;100次循环后,Na_2Li_2Ti_6O_(14)材料的电荷转移电阻增加,锂离子扩散系数略有下降,表明Na_2Li_2Ti_6O_(14)材料在循环后SEI膜的生成,降低了材料的电化学活性。     

BZCY-(Li/Na)2CO3新型复合电解质材料性能研究

BaZr0.1Ce0.7Y0.2O2.9（BZCY）电解质与氧离子传导型电解质相比,质子迁移的电导活化能较氧离子更低,低温下具有更高的离子电导率,在固体氧化物燃料电池低温话发展过程中,质子传导型电解质将会是一个很好的选择。本研究采用均相共沉淀法合成BaZr0.1Ce0.7Y0.2O2.9（BZCY）粉体,并制备不同组成的BZCY- (Li/Na)2CO3复合电解质,初步研究了其结构与性能。实验结果表明,复合电解质中碳酸盐以无定形形态存在,BZCY与碳酸盐发生反应生成BaCO3杂相;复合电解质电导率在空气中600℃和450℃时分别可达到0.095Scm-1和0.071Scm-1,加湿氢气中分别可达到0.126Scm-1和0.075Scm-1。以BZCY- 20%(Li/Na)2CO3为复合电解质的单电池表现出良好输出性能,在600℃和500℃时输出功率密度可达741mWcm-2和258mWcm-2。     

NaOH和Na2SiO3对纤维板阻燃性能的比较研究

通过对比在纤维板表面涂覆NaOH和Na2SiO3溶液,基于小室燃烧法、垂直燃烧仪和极限氧指数等研究其阻燃性能.结果表明,表面改性纤维板的阻燃性能排序为:涂Na2SiO3纤维板>涂NaOH+Na2SiO3纤维板>涂NaOH纤维板>未处理纤维板>泡水处理纤维板,单面涂覆的阻燃性能优于双面涂覆,极限氧指数可达25.2%.提出了NaOH与Na2SiO3对中密度纤维板的阻燃机理,涂覆NaOH溶液易使纤维板的阻燃物质迁移至表面,掺入的Na2SiO3可在纤维板表面形成含(=)Si-O-Si(=)链的三维网状硅质层,进而提高其阻燃性能.     

碱熔—碘量法测定矿石中的砷

采用碱熔—碘量法测定矿石中的砷,对碘标准溶液标定方法、熔样温度与时间、还原剂碘化钾用量、饱和碳酸氢钠溶液等实验条件进行了优化。该方法测定结果的相对标准偏差为0.40%~1.59%,加入标准物质回收率为95.00%~103.20%,测定结果准确、稳定,且操作简单,适合批量矿石的测定。     

复合抗氧化剂在柑橘-枸杞果酒中应用效果研究

为寻找适合柑橘-枸杞果酒抗氧化的复合抗氧化剂,通过单因素试验研究抗坏血酸、竹叶黄酮、乙二胺四乙酸二钠（EDTA-2Na）、茶多酚对柑橘-枸杞果酒抗氧化效果的影响,在此基础上采用正交试验得出最优复合抗氧化剂的配方为：抗坏血酸0.6‰、竹叶黄酮0.07‰、EDTA-2Na 0.026‰、茶多酚0.06‰。用此复合抗氧化剂来代替发酵过程中的SO2,果酒的理化指标（酒精度、总酸、总糖、还原糖等）没有明显的变化而挥发性成分更优,致使其感官评分有所提高。柑橘-枸杞果酒色泽亮黄、透明、果香与酒香和谐。