铋膜电极差分脉冲溶出伏安法同时测定食物中的锌和铜

[目的]研究用铋膜电极代替汞膜电极同时测定食物中锌和铜元素含量的新方法.[方法]以预镀铋膜的玻碳电极作为工作电极,饱和甘汞电极作为参比电极, 铂电极作为辅助电极, 采用差分脉冲溶出伏安法同时测定黄豆和板栗样品中锌和铜元素的含量.考察了镀铋液浓度、底液的种类和浓度、初始电位、电沉积电位、终止电位及电位增量等对试验结果的影响.[结果]在1.0 mol/L硫氰化钾底液中,锌和铜均有灵敏的溶出峰,线性范围分别为0.20～12.00和0.10～6.00μg/ml, 检出限分别为2.08、5.49μg/L,回收率为91.20%～104.50%.在所选择的电位范围内, 铋膜稳定性较好, 多次测定锌和铜的峰电流基本不变.[结论]铋膜电极差分脉冲溶出伏安法简便快速、灵敏度高,适合于食物中锌和铜元素含量的同时分析.     

离子交换膜燃料电池铂碳复合电极材料塔菲尔常数测试分析

利用极化曲线测试法分析了不同碳材料和不同方法制备的铂碳复合电极的塔菲尔常数。不同碳材料制备的铂碳复合电极塔菲尔常数值呈现出一定的差别,并且按碳材料的一定排列次序,铂碳复合电极的塔菲尔常数ａ值和ｂ值都呈现出了规律性的递减,其中ａ值递减相对较大;另外,不同方法制备的铂碳复合电极塔菲尔常数也呈现出了较大的差别,其中离子溅射法制备的铂碳复合电极塔菲尔常数值明显低于吸附还原法和电镀法制备的铂碳复合电极。同时     

汞膜电极的某些性质讨论及阳极溶出伏安法在有色轻金属极谱分析中的应用

本文对铂球镀银汞膜电极的制备和某些性质进行了讨论;对常用汞膜电极、玻璃炭电极和悬汞电极在性能上做了比较;阐述了汞膜电极在有色轻金属极谱分析中的具体应用。     

金属卤化物灯钼片引出线制作工艺的研究

金属卤化物灯的钼片引出线是灯泡电极引出线，它由钼基片、钼杆和镀铂钼过渡片组成，通过钼镀铂工艺研究，找出了一整套钼上镀铂的合理工艺。将镀过铂的钼过渡片与钼基片点焊，钼杆与钼基片在另一端点焊，组成钼片引出线。在制作过程中，摸索出控制焊接质量的工艺规范，如电极材质的确定，功率的调整，保护气氛的选择，模板、电极夹具的设计和改装等。用这种钼相引出线制成的金卤灯，经２０００小时点灯寿命试验后，能达到预期的效果。     

化学镀方法制备钯/多孔TiAl合金复合膜

通常采用无机膜分离技术中的钯合金膜扩散法制备超高纯氢(99.999%以上).因此,研究高性能钯合金膜具有很大的现实意义.该文作者采用化学镀的方法,在TiAl多孔材料表面上成功地镀上一层钯膜;运用XRD和SEM等测试手段,对TiAl多孔材料载体和钯膜进行表征.研究表明,采用化学镀方法制备钯/多孔TiAl合金复合膜,过程不需要活化,TiAl多孔材料载体表面的钯膜厚度为10～15 μm,与载体之间结合良好;该复合膜具有较好的选择透过性,在压差△P=0.18 MPa及500℃条件下,其选择性大于120,通量为0.29 mol/(m2.s).     

极化膜离子选择性电极的初步研究

前言经典的第二类电极作为内参比电极,电位滴定中的指示电极已有不少研究和应用。但作为离子选择电极,在直接电位法测定离子活度中应用却是聊聊无几。普遍地认为用阳极极化法制备的极化膜电极(即属于第二类电极)性能不如固态压膜电极好,因而不被人们重视。一些综合报导中,多数没有把极化膜电极归于离子选择电极之列。实际上极化膜电极有压膜电极所没有的某些优点。如固态压膜电极制作工序很烦琐,需要经过制备纯净的沉淀,而后再压片、抛光、粘合等工艺。而极化膜电极却比较简单,一般实验室都可     

银球汞膜电极的应用

为了减少汞害和提高分析方法的灵敏度,近年来对不同类型汞膜电极的制作、性能和应用进行了研究。如灵敏度很高的玻碳电极、渗蜡电极、铂球镀银—汞膜电极、悬汞电极、银丝银球汞膜电极、金银醮汞电极和铂体汞膜电极等。我们试制了铂丝—银球—汞膜电极。实践证明,选择合适的底液,对测定镉它是完全可以代替滴汞电极的,这就减少了汞的用量,提高了灵敏度。如与示波极谱法结合使用,可使测定的上限和下限扩大,0.01—100ppm范围内成线性关系,且操作简     

稀土在化学镀制备钯无机复合膜中的应用研究

在传统的化学镀镀液中分别添加 Y- L a、Y- Pr和 Y- Nd等混合稀土制备钯 /α- Al2 O3无机复合膜。重点研究了在镀液中添加混合稀土对钯的沉积速度、镀膜温度和膜表面结构的影响 ,并用扫描电镜对钯膜表面形貌进行了表征。实验结果表明 :在镀液中分别添加适量的 Y- L a、Y- Pr和 Y- Nd等混合稀土 ,可提高镀速 31%～ 6 0 %、降低镀温 10℃～ 2 0℃、缩小钯膜的晶核尺寸和提高膜的致密性。     

用汞膜电极快速极谱法连续测定铜锌矿石中的铜锌

铜锌矿和浮选原、尾矿中铜和锌的测定,一般多采用氨性底液极谱法,该法具有快、简和准的优点,但因用汞量大易引起中毒不安全.本文研究用汞膜电极代替滴汞电极,在氨性底液中用快速极谱法连续测定矿石中的铜锌,经试验取得满意的结果.本法具有经典极谱法的优点、同时减少汞毒的污染,改善了工作环境.汞膜电极在分析中的应用已有介绍,本法选用球形汞膜电极一铂球镀银沾汞电极,它的电压范围与悬     

铋膜电极微分电位溶出法测定矿区土壤中锡

研究了以镀铋膜电极替代镀汞膜电极测定锡的微分电位溶出分析法(DPSA),考察了测定锡的条件。结果表明,在富集电位为-1.2 V,清洗电位为0.50 V,草酸浓度为0.15 mol/L,CTMAB浓度为6.0×10-5mol/L的条件下,锡在镀铋膜电极上可产生灵敏的微分电位溶出峰,峰高与锡浓度在0~100.0μg/L范围呈线性,溶出电位为-0.54 V(vs.SCE),共存的铅不干扰锡的测定。建立的方法已用于矿区土壤中锡的测定,测定结果的相对标准偏差为2.4%~8.7%,加标回收率在98.5%~110%间。     

碳纤维表面沉积碳化钨膜研究

通过W(CO)6化学气相沉积(MOCVD)工艺,在碳纤维表面沉积得到了碳化钨膜材料,研究了碳纤维表面沉积碳化钨膜的工艺条件.结果表明:在400℃沉积温度下沉积时间15min,一定浓度的W(CO)6可解离沉积在碳纤维表面形成致密碳化钨膜;膜层厚度0.4μm,物相为WC1-x相,与碳纤维基体结合强度高.DTA分析表明,复合...     

Effects of Nitrogen Flow Rate on the Performances of Cathodic Arc Deposited TiN Films on 316L Stainless Steels as Bipolar Plates for the Proton-Exchange Membrane Fuel Cell

The corrosion resistance, interfacial contact resistance (ICR), and hydrophobicity of cathodic arc deposited TiN films on 316L stainless steels at different nitrogen flow rates as bipolar plates (BPs) for the proton-exchange membrane fuel cell (PEMFC) are investigated. It is shown in the results that the TiN-coated 316L stainless steel prepared at a moderate nitrogen flow rate (250 sccm) exhibits a low stable corrosion current density of 6.5 × 10⁻⁸ A cm⁻² in the simulated corrosive cathode environment of PEMFC, and a low ICR of 8.94 mΩ cm⁻² at a pressure of 1.38 MPa after corrosion, meanwhile presents a good hydrophobicity before and after corrosion. These results are discussed by considering the probable effects of the nitrogen flow rate on the substrate/coating system based on the microstructural characterization of the substrate/coating interface and the coating, which shows that the interdiffusion will be started in the deposition process and a moderate nitrogen flow rate during the coating process will promote to the broadening of interface region and lead to the formation of a robust and high-quality coating with fewer defects that can effectively improve the performances of the 316L stainless steel substrate as the BP for PEMFC.     

浸渍模压与CVD复合工艺制备质子交换膜燃料电池用炭纸

以干法成形技术制备的炭纤维坯体为预制体,酚醛树脂作粘结剂,通过浸渍、模压、炭化、CVD和石墨化制备质子交换膜燃料电池用炭纸.借助扫描电镜(SEM)观察炭纸表面形貌,用四探针法测试炭纸面电阻.研究结果表明:浸渍模压与CVD复合工艺在炭纤维表面形成连续均匀的热解炭层,增强纤维与基体的结合,减少裂纹缺陷,提高炭纸的导电性能;炭纸横向和纵向的面电阻分别为0.34 Ω和0.37 Ω,小于日本东丽炭纸的面电阻0.43Ω和0.70Ω.     

Accelerated study on lysozyme deposition on poly(HEMA) contact lenses

A technique was developed to accelerate lysozyme deposition on poly(HEMA) contact lenses and measure the amounts of the deposited lysozyme. This technique was for evaluation of bendazac lysine solution, a contact lens cleaning and wetting solution. Effect of temperature on lysozyme deposition on poly(HEMA) contact lenses was examined. Five temperatures ranging from 25 degrees C to 90 degrees C were chosen to examine the temperature effect. The amounts of lysozyme deposited on poly(HEMA) contact lenses at 25 C and 60 C were 0.27 microg/lens and 0.61 microg/lens, respectively. The amount increased sharply to 23 microg/lens at 70 degrees C with the maximum of 31 microg/lens at 90 degrees C. Kinetics of lysozyme deposition on poly(HEMA) contact lenses was examined at 80 degrees C. Lysozyme deposition increased sharply during the first 2 h and reached a plateau after 2 h. Effectiveness of various cleaning procedures was examined using bendazac lysine solution. When the contact lenses were washed without rubbing with fingers, the bendazac lysine reduced the amount of deposited lysozyme by more than 40% from 18.3 microg/lens to 10.6 microg/lens. The effect of bendazac lysine was most prominent when the contact lenses were shaken during storage in the presence of lysozyme in solution. If the contact lenses were cleaned by rubbing with fingers, the effect of bendazac lysine solution on the prevention of lysozyme deposition was negligible.     

Synthesis, characterization and thermostability of tris（2,2,6,6-tetramethyl-3,5- heptanedionato）yttrium（III）

The metal-organic chemical vapor deposition (MOCVD) technique is a promising process for high temperature superconductor YBa2Cu3O7-δ(YBCO) preparation. In this technique, the purity, evaporation characteristics and thermostability of adopted precursors will decide the quality and reproducible results of YBCO film. In the present report, tris(2,2,6,6-tetramethyl-3,5-heptanedionato)yttrium(III)(Y(TMHD)3) was synthesized by the interaction of yttrium nitrate hydrate with TMHD in methanol solution, and its structure was identified by FTIR, 1 H NMR, 13C NMR and EI-MS spectroscopy. Subsequently, the thermal property and the kinetics of decomposition were systematically investigated by non-isothermal thermogravimetric analysis methods (TGA) at different heating rates in streams of N2,and the average apparent activation energy of evaporation process was evaluated by the Ozawa, Kissinger and Friedman methods. The possible conversion function was estimated through the Coats-Redfern method to characterize the evaporation patterns and followed a phase boundary reaction mechanism by the contracting area equation with average activation energy of 88.9kJ/mol.     

焦炉煤气单乙醇胺法脱硫脱氰的生产及改进

用单乙醇胺（ＭＥＡ）法脱除焦炉煤气中的Ｈ２Ｓ，ＨＣＮ能满足冶金工厂的要求，但蒸汽、ＭＥＡ的消耗较大，对于老焦化厂新增设脱硫脱氰，采用单醇胺法－－硫酸工艺较好，文章论述了ＭＥＡ法脱硫脱氰的原理及生产流程，并提出了其存在的问题及解决的方法。     

Deposition and Characterization of (Ba, Sr)RuO3 Oxide Electrode Using TMHD-Based Single Cocktail Source

(Ba, Sr)RuO3 has been paid an attention as a promising electrode for (Ba, Sr)TiO3 dielectric material due to its similarity in structure and chemical composition with BST. In this study, (Ba, Sr)RuO3 conductive oxide film was deposited on a 4 inch p-type Si wafer by metal organic chemical vapor deposition (MOCVD) using single cocktail source for the practical device application. Ba(TMHD)2, Sr(TMHD)2, Ru(TMHD)3 precursors and solvent [1-EtylePiPerdine (C7H15 N) ] as starting materials were mixed together for single cocktail source. A liquid delivery system (LDS) and a vaporization cell were utilized for the delivery and vaporization of single cocktail source, respectively. The source feeding rate was controlled by a liquid mass flow controller (LMFC). Deposition parameters, such as the oxygen flow and the source flow rate,were sensitive to phase formation, resistivity and the composition ratio of (Ba, Sr)RuO3 films. Highly (110)-textured (Ba,Sr)RuO3 film was obtained vhen the Ar/O2 ratio was 200/140 sccm at a source flow rate of 0.05 sccm. The process window of stoichiometric composition of BSR film was observed with varying the source flow rate from 0.05 sccm to 0.1 sccm.     

电感耦合等离子体质谱法测定Oleflex催化剂中铂

Oleflex工艺越来越受到关注,其所用Oleflex催化剂中的Pt含量对催化剂活性有较大影响,因此迫切需要一种高效稳定的检测Pt的方法。采用王水溶解样品,通过对绘制校准曲线用标准溶液系列进行Al基体匹配的方法消除基体效应,以¹⁹⁵Pt为测定同位素,建立了电感耦合等离子体质谱法(ICP-MS)测定Oleflex催化剂中Pt含量的方法。对等离子体气流量、测定介质进行了优化,确定等离子体气流量为10.5L/min,测定介质为2%HCl(V/V)。考察了基体Al对Pt测定的影响,结果表明,其负影响比较显著。用ICP-MS对样品溶液中的Al含量进行了测定,结果表明,无论称样量为0.1g还是0.2g,最终被溶解的Al₂O₃占催化剂的质量比均为19%左右。因此,实验选定称样量为0.1g,采用基体匹配法使得校准曲线用标准溶液系列中Al的质量浓度均为40μg/mL来消除基体效应。在选定的实验条件下测定Pt标准溶液系列,以Pt的质量浓度为横坐标,其对应的分析信号强度为纵坐标绘制校准曲线。方法的线性范围为0.001~2.00μg/mL,线性相关系数为0.9999,检出限为0.0004μg/mL。对新鲜Oleflex催化剂、再生Oleflex催化剂和废Oleflex催化剂样品按实验方法测定Pt含量,测定结果的相对标准偏差(RSD,n=5)为1.5%~2.8%,加标回收率为97%~104%。用实验方法与标准方法GB/T 23524—2009分别测定上述3种Oleflex催化剂样品中Pt,用t检验对测定结果进行验证。结果表明,两种方法测定样品中Pt含量的结果没有显著性差异。     

ACF/CNT复合材料的制备及其对Cr(Ⅵ)的吸附性能

以硝酸镍为催化剂前驱体,C2H2为碳源,H2为还原气,N2为载气,采用化学气相沉积法(CVD)在活性炭纤维(ACFs)毡体的纤维表面催化生长碳纳米管(CNTs),制备ACF/CNT复合材料。经测定,所制复合材料比表面积可达62.56 m2/g;扫描电镜分析表明,CNTs在ACFs表面分布均匀而致密,经过表面修饰可以作为1种良好的吸附材料。选择低浓度的六价铬(Cr(Ⅵ))溶液进行吸附研究,考察振荡时间、溶液pH值以及溶液的初始浓度等因素对吸附行为的影响。实验结果表明,初始Cr(Ⅵ)浓度为1 mg/L,在25℃时,随着振荡时间的增长溶液中Cr(Ⅵ)的脱除率逐渐增加,在150 min时达到最大值49.48%。溶液中Cr(Ⅵ)的脱除率随着pH的减小而增大,当pH值为2.0时脱除率达91.50%,对Cr(Ⅵ)的吸附量随着溶液初始浓度的增加而增大,但是当初始浓度到达5.0 mg/L时,脱除效率到达最大值后开始降低。并对ACF/CNT复合材料的吸附机制进行了探讨。     

A Comparison Study on Corrosion Resistance of 430 Stainless Steel Surfaces Modified by Alkylsilane and Fluoroalkylsilane SAMs

The self-assembly monolayers (SAMs) of n-dodecyltriethoxysilane (DTES) and 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (PFDS) on the surface of the 430 stainless steel (430SS) were prepared and their corrosion protection performance was investigated by potentiodynamic polarization, Fourier transform infrared spectroscopy (FTIR) -attenuated total reflection (ATR), static contact angle and atomic force microscopy (AFM). The results showed that the alkali pretreatment and the water added into the self-assembly solution could generate more hydroxyls on the 430SS surface, and then enhanced the adsorption of the SAMs. A suitable temperature of the self-assembly solution is important for the formation of the SAMs. The silane SAMs were chemically adsorbed on the 430SS substrates by Fe-O-Si bonds. In all cases tested, PFDS has a better inhibition effect compared with DTES, and the difference in inhibition effect is most marked at the lowest concentration of 1 mmol/L.