反复熔铸对镍铬烤瓷合金离子析出影响的研究

根据ISO10271标准,将镍铬烤瓷合金在真空加氩气保护的铸造条件下,按口腔铸造要求分别经过1～5次熔铸制成方形试样,并在空气中960℃加热10min.试样抛光后浸泡于pH=2.35的0.1mol·L(-1)氯化钠溶液中,37℃密封保存7和70d后采用电感耦合等离子体原子发射光谱仪检测溶液中析出的离子,同时测量试样重量...     

Etching mechanism of barium strontium titanate （BST） thin films in CHF_3/Ar plasma

Reactive ion etching was used to etch barium strontium titanate thin films in a CHF3/Ar plasma.BST surfaces before and after etching were analyzed by X-ray photoelectron spectroscopy to investigate the reaction ion etching mechanism,and chemical reactions had occurred between the F plasma and the Ba,Sr and Ti metal species.Fluorides of these metals were formed and remained on the surface during the etching process.Ti was almost completely removed because the TiF4 by-product is volatile.Minor quantities of Ti?F could still be detected by narrow scan X-ray photoelectron spectra,and Ti?F was thought to be present in the form of a metal-oxy-fluoride.These species were investigated from O1s spectra,and a fluoride-rich surface was formed during etching.BaF2 and SrF2 residues were difficult to remove because of their high boiling point.The etching rate was limited to 12.86 nm/min.C?F polymers were not found on the surface,indicating that the removal of BaF2 and SrF2 was important for further etching.A 1-min Ar/15 plasma physical sputtering was carried out for every 4 min of surface etching,which effectively removed remaining surface residue.Sequential chemical reaction and sputtered etching is an effective etching method for barium strontium titanate films.     

Enhanced low-temperature performance of slight Mn-substituted LiFePO<Subscript>4</Subscript>/C cathode for lithium ion batteries

Low temperature performance of LiFePO₄/C cathode was remarkably improved by slight Mn-substitution. Electrochemical measurements showed that about 95% of the discharge capacity of LiFe_0.98Mn_0.02PO₄/C cathode at 20°C was obtained at 0°C, compared to 85% of that of LiFePO₄/C cathode. The LiFe_0.98Mn_0.02PO₄/C sample also presented enhanced rate performance at −20°C with the discharge capacities of 124.4 mA h/g (0.1C), 99.8 mA h/g (1C), 80.7mAh/g (2C) and 70 mA h/g (5C), respectively, while pristine LiFePO₄/C only delivered capacities of 120.5 mA h/g (0.1C), 90.7 mA h/g (1C), 70.4 mA h/g (2C) and 52.2 mA h/g (5C). Cyclic voltammetry measurements demonstrated an obvious improvement of the lithium insertion-extraction process of the LiFePO₄/C cathode by slight Mn-substitution. The results of FSEM observation and electrical conductivity measurement indicated that slight Mn-substitution minimized the particle size of LiFe_0.98Mn_0.02PO₄/C and also obviously improved the electrical conductivity of the compound, thus obviously enhances the interface reaction process on the cathode.     

铜离子对日本黄姑鱼幼鱼的急性毒性

采用静水生物测试法研究了不同暴露时间下铜离子对日本黄姑鱼幼鱼的急性毒性效应,建立了不同暴露时间下Cu2＋浓度与日本黄姑鱼死亡概率的回归方程,暴露时间分别为24 h、48 h、72 h和96 h时,Cu2＋对日本黄姑鱼死亡概率的线性回归方程分别为Y=8.907 5 X＋0.526 3、Y=9.439 2 X＋0.601 2、Y=9.805 6 X＋0.683 5和Y=10.558 X＋0.574 3,通过回归方程计算得出Cu2＋对日本黄姑鱼的相应半致死浓度分别为3.178 mg/L、2.924 mg/L、2.755mg/L和2.63 mg/L。根据化学品对鱼类急性毒性的危害分级标准,Cu2＋对日本黄姑鱼的危害级别为高毒。     

足球运动中踝关节损伤的治疗及疗效对比

运动员关节损伤后如何有效治疗及使其尽快康复,具有重要意义。通过对山西路虎足球队冬训期间14名踝关节急性损伤的运动员运用按摩、针刺、中药离子导入疗法进行治疗,并对有中药离子导入与无中药离子导入的治疗进行对比,观察疗效。经过14 d治疗及康复,有中药离子导入疗法组有效率100%,平均治疗天数10 d;无中药离子导入疗法组有效率71.42%,平均治疗天数14 d。可见,中药离子导入配合手法按摩及针刺的疗法对踝关节急性损伤的治疗具有较好的效果。     

新型TCAS吸附树脂对水中Cu2+的吸附去除研究

通过静态吸附试验,研究一种由超分子受体化合物磺化硫杂杯芳烃(TCAS)与树脂结合的产物-新型TCAS吸附树脂对重金属Cu2+的吸附去除性能,并初步探讨了吸附机理。试验研究结果表明:当温度为20℃,0.5gTCAS吸附树脂对10 mL浓度为5.0 mg.L-1的Cu2+溶液吸附120 min时,Cu2+的去除率可达到99%以上,pH值对TCAS吸附树脂吸附重金属的影响不大,吸附在TCAS吸附树脂上的Cu2+可洗脱回收,TCAS吸附树脂也可再生利用。     

Fe3O4磁流体对铀（VI）的吸附研究

为降低铀对环境的影响,研究纳米磁流体对铀(VI)的吸附行为.用沉淀法制备了磁粒径10~20nm的Fe3O4磁流体,考察了该磁磁流体对铀(VI)吸附的各种影响因素,结果表明:在纳米磁流体浓度为2.5g/L、温度35℃、pH=3、吸附时间t=30min的条件下,对3×10-4mol/L铀的吸附萃取率可达到84.15%.该吸附过程符合假设的二级动力学模型.     

镉(II)离子印迹聚合物的制备及其吸附性能研究

利用分子印迹技术制备了重金属镉(Ⅱ)的印迹聚合物,并对其识别性能进行定量描述.以镉(Ⅱ)离子为模板,安息香肟为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,采用本体聚合法制备印迹聚合物.实验结果表明,与未印迹的聚合物相比较,印迹聚合物对镉(Ⅱ)离子具有较好的识别选择性,达到吸附平衡的时间为50 min,初始浓度为10 mg/mL时,吸附量为2.12 mg/g,并推测了该印迹聚合物和镉离子的识别机理.     

固体电解质Li_(1+2x+2y)Al_xMg_yTi_(2-x-y)Si_xP_(3-x)O_(12)系统的合成及导电性能的研究

以LiTi2(PO4)3为基,煤矸石为原料经高温固相反应(900℃)制得系列锂离子固体电解质Li1+2x+2yAlxMgyTi2-x-ySixP3-xO12(以下简称Ti-Mg-Lisicon).应用交流阻抗技术测定的电导率数据结果表明x=0.1,y=0.1的合成物室温电导率比较理想为1.30×10-4S/cm,而673 K时x=0.1,y=0.3的合成物的电导率最大,为2.60×10-2 S/cm。X射线衍射分析结果表明在x=0.1,y≤0.7x;=0.2y,≤0.6的组成范围内均得到空间群为R3c的合成物.     

茜素红“开关式”荧光探针测定水中微量铜

当pH=5.2时茜素红与过量的Al³⁺反应生成发射橙黄色荧光的络合物,该络合物的最佳激发和发射波长分别为469 nm和585 nm,Cu²⁺能够使茜素红-铝体系荧光猝灭,且荧光猝灭程度与Cu²⁺的浓度在一定范围内呈线性关系,据此建立了一种灵敏的“开关式”测定Cu²⁺的方法.探究了茜素红-铝-铜体系的最佳用量比、反应温度、反应时间、pH、缓冲溶液等因素对反应体系的影响.结果表明:测定Cu²⁺的工作曲线为 ΔF=19.7c+101.2,R²=0.999 5,线性为0.2~30 μmol/L,检出限0.022 μmol/L.该方法准确度高,灵敏度高,选择性好,可用于水中微量铜的检测.