Study on the passive film formed on 2205 stainless steel in acetic acid by AAS and XPS

The properties of the passive film formed on 2205 stainless steel in acetic acid at high temperature that contained chloride ions were studied by atomic absorption spectrometry (AAS), X-ray photoelectron spectroscopy (XPS), and electrochemical polariza-tion measurements.AAS results show that molybdenum is enriched on the surface as the passive film is dissolved.This enrichment decreases the corrosion resistance because it hinders chloride adsorption and Fe ion dissolution, and acts as a local pH buffer because it consumes protons.The dissolution ratio of Fe/Cr is approximately 10 during the active dissolution of the passive film.XPS results indicate that when the potential is in the passivation region, Cr comprises about 50% of the metal cations in the near-surface region of the passive film and is the main metal constituent in this region.When the polarization potential is much greater than the transpas-sivation potential, the Mo content accounts for approximately 45% of the metal cations in the near-surface region; Fe and Ni have no obvious influence on the formation, dissolution, or puncture of the passive film.     

Corrosion resistance of 316L stainless steel in acetic acid by EIS and Mott-Schottky

The properties of the passivation film formed on 316L stainless steel were studied by Electrochemical Impedance Spectroscopy （EIS）, Mott-Schottky and Voltammetry measurements in high- temperature acetic acid. The results show that the passivation film formed on 316L stainless steel is stable in 60% acetic acid solution from 25 ℃ to 85 ℃. As temperature increased, the polarization resistance decreased but the interface capacitance increased. There was hardly any relation between temperature and the intrinsic property semiconductor. The passivation film represents the p-semiconductor property in the potential interval of -0.5-0.1 V; represents the n-semiconductor property in the potential interval of 0.1-0.9 V; and represents the p-semiconductor property in the potential interval of 0.9-1.1 V. The voltammetry measurements show that the structure of the passivation film is stable when the temperature is lower than 55 ℃ and that its stability decreased when this temperature is exceeded.     

固定化细胞法生产醋酸影响因素的研究

以海藻酸钠为载体,还研究了固定化细胞的制备,对接种环数、种子培养时间进行了优化,还研究了不同乙醇初始浓度对醋酸产量、菌体个数、菌体生长周期、葡萄糖消耗量、乙醇消耗量的影响。获到如下结论：优化接种数为15环、培养时间为36～48h之间;葡萄糖浓度与OD值的换算公式：Y=4．723 7x;菌体个数与菌液OD值的相关性：y=402．88x;体积分数5％乙醇时发酵液醋酸转化率最高,最佳培养时间为96h;乙醇体积分数越高,菌体生长延迟期越长;乙醇的含量越高,则葡萄糖的消耗就越少;培养时间为72h时,乙醇消耗完毕,由于中间产物乙醛的存在,醋酸在72～96h时间段继续生成。     

苹果梨醋发酵过程中醋酸发酵条件的优化

以甲酚紫培养基中加入乙醇作为分离培养基,从5种水果样品中分离得到20种醋酸菌,然后通过产酸量的测定,筛选出了一株产醋酸度高的醋酸菌AAB13.探讨了乙醇浓度、菌株接种量、发酵液有效体积对醋酸发酵的影响,并在优化的条件下制备了苹果梨醋.     

醋酸菌对苹果汁酒精发酵的影响

以浓缩苹果汁为原料,分别在裂殖酵母酒精发酵的前、中和后期接入醋酸菌。结果表明,随着醋酸菌接种时间的延后,对酵母酒精发酵的影响逐渐减小。在前期接入醋酸菌明显抑制酵母的代谢活性,使降糖和产酒速率降低,发酵周期延长,但不影响最终残糖量和酒精产量;在中期接入醋酸菌能与酵母菌共同生长,且缩短了酒精发酵周期;在后期接入醋酸菌对酒精发酵几乎无影响。     

3-噻吩甲氧基乙酸衍生物的合成

报道3噻吩甲氧基乙酸衍生物的合成.化合物6a~6e,7,8,9a,9b,10a~10c为尚未见报道的新化合物,其结构经红外光谱、核磁共振氢谱及元素分析所证实.     

冰乙酸和胃蛋白酶依次提取新鲜林蛙皮胶原蛋白

采用冰乙酸和胃蛋白酶依次对新鲜林蛙皮胶原蛋白进行提取.在冰乙酸提取过程中,首先通过控制单一因素变量对料液比、pH值、冰乙酸浓度、酸解时间和温度等5个因素对新鲜林蛙皮胶原蛋白提取率的影响进行研究,并采用正交实验考察林蛙皮胶原蛋白酸解提取的最佳工艺;其次,在冰乙酸提取的最优条件下,利用胃蛋白酶将酸解后的残余物进行再次酶解提取.实验结果表明,最佳酸解的工艺条件是:料液比为1∶30,pH为7.5,酸解时间为48 h,酸解温度为4℃,冰乙酸浓度为0.5 mol/L.在此工艺条件下,胶原蛋白的提取率为11.85％,胃蛋白酶对蛙皮残渣的提取率为5.25％,所得胶原蛋白的纯度为64.70％.     

脉冲偏压对铝合金上TiN膜生长的影响

为了研究在铝合金上硬质膜的性能,促进硬质TiN膜在铝合金构件上的应用,利用电弧离子镀在7075铝合金上沉积TiN膜层,并通过改变脉冲偏压幅值研究其对薄膜生长过程的影响.结果表明,生长的TiN膜具有柱状特征,在无偏压或低偏压时,柱状特征明显,但随着负偏压值的增大,柱状特征变得不明显,膜层中Ti和N的原子比率增加,由无偏压、低偏压时近似为1.0增加到-200V偏压时的1.2.在0～-200V偏压范围内,沉积膜的平均生长速率由1.5μm/h增加到11.3μm/h.随着负偏压的增加,TiN膜的(111)方向的择优取向越来越明显,而(200)方向强度越来越小.沉积膜呈柱状生长,具有明显的择优取向,其程度受脉冲偏压影响.     

微波散射MCM-41介孔分子筛担载醋酸镧的制备及表征

水热法合成了纯硅MCM-41介孔分子筛,通过微波散射制备了系列不同硅镧摩尔比的LaAc／MCM-41（LaAcM）介孔分子筛。通过XRD、IR、N2吸附脱附等方法对分子筛的晶体结构和表面物性进行了表征。结果表明,当担载量n（Si）：,2（La）=30：1．0时,LaAcM Hammett碱量最大,为0．20mmol／g,／40介于＋6．8与＋4．6之间,比表面积为1287m^2／g,孔容0．8273cm^3／g,孔径2．571nm。样品具有典型的六方介孔结构特征。     

Application of ceramic film as means of lubrication for forming of Ti sheet in a highly localized deformation process

Incremental forming is a novel die-less sheet forming process. There is a need for special means to retain lubricant at the tool/sheet interface during forming. To fulfillthe stated aim, a porous ceramic film was developed on pure Ti substrate, and it was done through an electrochemical depsition process known as plasma electrolytic oxidation. The film with preferred pore size could be realized after several attempts by varying the processing parameters. In order to characterize the film, a variety of tests including rnicrostructure, film-substrate bond strength and tribological properties tests were conducted. On-job performance of the film was also examined by forming Ti components employing a range of forming conditions. It was found that the proposed method of lubrication was effective, and the plasma eletrolytic oxidation process can be employed to fabricate films on pure Ti sheet to provide means of lubrication during incremental forming.     

自组装3-氨丙基三甲氧基硅烷-磷钼酸膜修饰电极

通过在C-O-Si键在电化学活化玻碳电极表面自组装3-氨丙基三甲氧基硅烷(3-aminopropyltrimethoxysilane, APMS),再于其表面连接Keggin型结构杂多酸阴离子PMo12O403-,制备了复合膜修饰玻碳电极,采用XPS和循环伏安法研究了复合膜的基本性质。结果表明,PMo₁₂O₄₀^3-通过库仑作用力与APMS的表面-NH₂结合 (PMo₁₂O₄₀^3--APMS),可极大提高电极的稳定性,与溶液中的PMo₁₂O₄₀^3-相比,PMo₁₂O₄₀^3--APMS修饰电极表现出具有较小峰-峰分裂的PMo₁₂O₄₀^3-的三对可逆氧化还原过程,并能在较大pH范围内保持稳定。研究了修饰电极对ClO₃^-、BrO₃^-、IO₃^-还原的催化性能,与PMo₁₂O₄₀^3-修饰玻碳电极相比,该电极对三种离子均具有良好的电催化活性,对应的检出限分别为1.5×10^-5、1.0×10^-6、5×10^-7mol／L。     

Effect of acetic acid on electrochemical deposition of carbon-nitride thin film

Electrochemical deposition method was employed to prepare CNx thin film from methanol-urea solution,and it was shown that adding a little acetic acid in the solution significantly affected the deposition process.After optimizing the experiment conditions,we obtained polycrystalline grains with sizes of about 3―7μm on the faces of single crystal silicon.X-ray diffraction spectrua indicate that the grains are mainly composed of cubic phase mixed with a small amount of β and α phases.     

sol-gel法制备WO3薄膜的成膜性研究

用sol-gel法在ITO导电玻璃上制备了WO3电致变色薄膜,用光学显微镜对所有薄膜进行拍照,对比薄膜的成膜情况.经观察发现,薄膜前驱液浓度、拉膜速度和杂质对成膜性均有显著影响.从拉膜的过程方面讨论了出现上述情况的原因.     

溅射条件对SiO2膜力学特性的影响

介绍了在不锈钢衬底和Ｎｉ－Ｃｒ应变电阻间ＳｉＯ２薄膜的制做方法，在不宜用热氧化和ＣＶＤ法制做ＳｉＯ２膜的情况下，利用该法是行之有效的．探讨了溅射工艺条件对膜附着力和应力的影响，并指出了制备具有较好附着力和较低应力的方法．     

植物生长调节剂对氯苯氧乙酸的合成研究

对氯苯氧乙酸是一种性能优良、价格低廉,应用前景广泛的植物生长调节剂,本文主要研究了以氯制剂与苯氧乙酸为原料合成对氯苯氧乙酸的工艺.最佳反应工艺条件为:温度控制在60~65℃反应3h,反应物摩尔比为苯氧乙酸∶浓盐酸=19∶.0(mol),催化剂用量为苯氧乙酸用量的0.85%.     

Influence of flux treatment on the glass forming ability of Pd-Si binary alloys

Pd81Si19 amorphous alloys were prepared by combination methods of melt spinning and B2O3 flux treatment. A compari- son between the ribbons prepared from the fluxed ingots and the non-fluxed ones has been carried out. The result reveals that after fluxing treatment the glass transition temperature of the as-prepared glassy ribbons is reduced while the initial crystallization tem- perature is enhanced. It results in that the supercooled liquid region (defined as the difference between the initial crystallization tem- perature and the glass transition temperature) of the glassy alloy treated with fluxing technology has been increased from 31 to 42 K. This shows that fluxing technique can enhance the glass forming ability (GFA) of the binary alloy and improve the thermal stability of supercooled liquid of the glassy alloy.     

苹果醋饮研制及氨基酸分析

以苹果汁为唯一底物,经过酵母菌和醋酸菌二次发酵,对苹果醋和苹果汁进行氨基酸含量分析,发现在发酵过程共生成8种氨基酸分别为:精氨酸7.1 mg/l,蛋氨酸0.7 mg/l,异亮氨酸4.9 mg/l,酪氨酸7.5 mg/l,苯丙氨酸6.9 mg/l,组氨酸5.3 mg/l,赖氨酸4.5 mg/l,甘氨酸24.2 mg/l.最后按果醋25%、苹果汁5%、蜂蜜6%、蔗糖3%调配苹果醋饮料,调配后苹果醋饮料中有氨基酸17种,乙酸含量为10 g/l,总糖为30 g/l.     

微波谐振腔内壁水膜对腔体特性的影响

应用微波谐振腔微扰理论分析了圆柱形谐振腔内壁水膜对腔体谐振频率和品质因数产生的影响,通过理论推导得到了由水膜引起的谐振频率偏移和品质因数变化的解析式,并对工作于9.6GHz的TE011模圆柱谐振腔进行了仿真分析,给出了谐振腔的谐振频率和品质因数随水膜厚度不同而发生变化的仿真曲线。结果表明,当水膜厚度小于10μm时,水膜对谐振腔的谐振频率和品质因数的影响可以忽略;当水膜厚度超过20μm时,需要考虑水膜的影响,对测量结果进行校正。     

呋喃丹在L-赖氨酸镍复合膜修饰电极上的电化学行为研究

在玻碳电极上用循环伏安法制备L-赖氨酸镍复合膜,并对其聚合条件进行研究.研究表明：在pH=7.0的PBS缓冲液中L-赖氨酸镍复合膜在玻碳电极上的电聚合过程为不可逆过程,有明显的还原峰.用循环伏安法初步探讨了呋喃丹在该复合膜上的电化学行为,测得在5.0×10^-6～1.0×10^-4mol/L的范围内,呋喃丹还原峰电流与其浓度呈良好的线性关系.该修饰电极可用于呋喃丹含量的分析,有良好的稳定性和抗干扰能力.     

薄板多点成形时不同的工艺方式对起皱的影响

采用有限元数值模拟手段针对多点成形过程中产生的起皱现象以及消除皱纹的措施进行了探讨.对比了多点模具成形和多点压机成形两种不同工艺,分析了不同的成形工艺条件对起皱的影响.用显式动力学软件对0.1 mm与0.5 mm厚度的马鞍型曲面件进行了数值模拟,结果表明,在多点模具成形方式下,采用无压边成形,使用弹性垫,成形0.5 mm厚度的板料时,曲率半径为100 mm的成形件起皱剧烈;但在相同条件下,用多点压机成形工艺的成形件结果良好,甚至成形厚度为0.1 mm的板料也没有起皱.表明多点压机成形方式比多点模具成形方式成形效果好,缺陷少,并且有利于板材的流动,能够得到更大的变形量.