Evaluation of Scale and Corrosion Inhibition of Modified Polyaspartic Acid

Amino acid modified polyaspartic acids were evaluated as calcium-scale inhibitors. Feasibility of scale inhibition experiments was analyzed by molecular dynamics simulation and Gaussian optimization, and the scale inhibition mechanism was theoretically analyzed. Scale inhibition performance was studied by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, static scale inhibition experiments, and electrochemical performance testing, which provided an experimental basis for the molecular dynamics simulation. The experimental results showed that Arg-SA-PASP has better scale inhibition and corrosion inhibition performance than His-SA-PASP. The scale inhibition effect increased with increasing concentration. Electrochemical tests indicated that Arg-SA-PASP is an excellent scale and corrosion inhibitor.     

Effects of different carbon sources and C/N values on nonvolatile taste components of Pleurotus eryngii

Pleurotus eryngii, the second largest industrial cultivation mushroom in China, is usually cultivated on substrates mainly consisting of sawdust and corncob. In this study, experiments were performed to determine the effects of different carbon sources and C/N values on nonvolatile taste components of P. eryngii. The effects of different carbon sources on nonvolatile taste components levels revealed that sawdust was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while corncob was beneficial to high contents of carbohydrate, polysaccharides and trehalose. At the similar C/N values, relatively higher sawdust content was beneficial to umami amino acid production, while relatively higher corncob content was beneficial to high contents of carbohydrate, polysaccharides and mannitol. Higher C/N value was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while lower C/N value was beneficial to high contents of carbohydrate, polysaccharides and trehalose. These results provided information for P. eryngii fruit body industrial cultivation to obtain specific nonvolatile taste components with high levels.     

苯乳酸抑制链格孢霉作用靶位的分析

以从自然腐败的樱桃上分离的链格孢霉（Alternaria sp.）LD3.0086为指示菌，研究苯乳酸对链格孢霉的主要抑制作用靶位。应用分光光度法测定苯乳酸对链格孢霉的最小抑菌浓度，通过卡尔科弗卢尔荧光增白剂染液（calcofluor white，CFW）染色观察苯乳酸对菌丝顶端生长的破坏作用，利用扫描电子显微镜和透射电子显微镜观察链格孢霉的超微结构变化，通过测定苯乳酸作用前后链格孢霉上清液中N-乙酰葡萄糖胺质量浓度变化研究苯乳酸对菌丝细胞壁的破坏作用，应用荧光双染色法观察苯乳酸对链格孢霉菌丝细胞膜的损伤作用。结果表明，12.5 mmol/L的苯乳酸能有效抑制链格孢霉的生长；与对照组（无菌水处理）相比，苯乳酸处理后链格孢霉顶端生长细胞无明显形变，经12.5 mmol/L苯乳酸处理的链格孢霉上清液中N-乙酰葡萄糖胺质量浓度基本不变；苯乳酸处理24 h，链格孢霉菌丝细胞壁表面无明显损伤，细胞内结构发生明显变化；苯乳酸短时间（4 h）处理链格孢霉，菌丝细胞膜仍较为完整，加入苯乳酸较长时间（8 h）后细胞膜发生破裂。综合分析可知，苯乳酸对链格孢霉的主要作用靶位应不是菌丝体的细胞壁和细胞膜，而是在菌丝体内部，通过破坏菌丝内部细胞器结构或引起细胞内的生化反应，从而抑制链格孢霉的生长和繁殖，发挥抑菌活性。     

Encapsulated sodium supplementation of 4 weeks does not alter salt taste preferences in a controlled low sodium and low potassium diet

Preference for saltiness is learned by oral exposure to salt taste; however, some data suggest a role for bodily sodium and potassium levels on salt taste preferences as well. The objective was to investigate whether encapsulated sodium and potassium supplementation lead to altered salt taste responses among adults with high blood pressure on a low sodium and low potassium diet. Twenty-six participants with untreated upper-range prehypertension or stage 1 hypertension were on a fully controlled low sodium and low potassium diet (both targeted at 2 g/day) for 13 weeks. Participants received capsules with sodium (3 g/d), potassium (3 g/d), or placebo, for 4 weeks each, in randomized order in a double blind crossover design. Sensory evaluation was done before and after each supplementation period and involved ratings of pleasantness and intensity in different salt (NaCl) concentrations in food and water, desire-to-eat salty food, and detection threshold for NaCl. Neither sodium supplementation nor potassium supplementation led to alterations in salt taste responses in food and water, and did not affect detection threshold (P = 0.59). There was no clear role for sodium or potassium supplementation on desire-to-eat salty food. In addition, we did not find effects of reduced oral exposure to salt over weeks, through the sodium-reduced diet, on salt taste preferences, in contrast to earlier studies. In conclusion, the results of this study suggest preference for saltiness is independent of changes in bodily sodium or potassium levels.     

多功能杀菌剂的合成及其性能研究

在现有季铵盐类杀菌灭藻剂上增加一个脂键，连接一个有机酸基团，合成一种兼具阻垢缓蚀功能的新型工业水处理用杀菌灭藻剂(多功能杀菌剂)，经一系列评价实验表明：新型杀菌剂是较理想的杀菌剂，在较低浓度下，对硫酸盐还原菌(SRB)及腐生菌(TGB)均有很好的杀灭效果，优于1227杀菌剂，同时还具有较好的缓蚀阻垢效果。     

N-油酰基肌氨酸钠对除盐水缓蚀性能的探讨

对N-油酰基肌氨酸钠单体的缓蚀性能以及与常用除盐水缓蚀剂的协同作用作了探讨,发现在一定浓度下,单体对经过加氨调节后的高温除盐水(氨后除盐水)有良好的缓蚀作用,且与大多数除盐水缓蚀剂有良好的协同效应。在此基础上研制了一种复合药剂,并对其缓蚀、阻蚀性能作了研究。动电位极化曲线扫描图谱表明,该复合药剂属于抑制阳极腐蚀的阳极型缓蚀剂,其适用的水质条件为[Cl~-+SO_4~(2-)]不超过50 mg／L,pH不低于8.0；与阻垢剂复配,可以适用于含Ca~(2+)不超过45 mg／L的水质条件。     

Rate of ammonia oxidation in a synthetic saline wastewater by a nitrifying mixed‐culture

Most of the kinetic studies on nitrification have been performed in diluted salts medium. In this work, the ammonia oxidation rate (AOR) was determined by respirometry at different ammonia (0.01 and 33.5 mg N‐NH₃ L^?1), nitrite (0–450 mg N‐NO₂^? L^?1) and nitrate (0 and 275 mg N‐NO₃^? L^?1) concentrations in a saline medium at 30 °C and pH 7.5. Sodium azide was used to uncouple the ammonia and nitrite oxidation, so as to measure independently the AOR. It was determined that ammonia causes substrate inhibition and that nitrite and nitrate exhibit product inhibition upon the AOR. The effects of ammonia, nitrite and nitrate were represented by the Andrews equation (maximal ammonia oxidation rate, r_AOMAX, = 43.2 [mg N‐NH₃ (g VSS_AO h)^?1]; half saturation constant, K_SAO, = 0.11 mg N‐NH₃ L^?1; inhibition constant K_IAO, = 7.65 mg N‐NH₃ L^?1), by the non‐competitive inhibition model (inhibition constant, K_INI, = 176 mg N‐NO₂^? L^?1) and by the partially competitive inhibition model (inhibition constant, K_INA, = 3.3 mg N‐NO₃^? L^?1; α factor = 0.24), respectively. The r_AOMAX value is smaller, and the K_SAO value larger, than the values reported in diluted salts medium; the K_IAO value is comparable to those reported. Process simulations with the kinetic model in batch nitrifying reactors showed that the inhibitory effects of nitrite and nitrate are significant for initial ammonia concentrations larger than 100 mg N‐NH₄⁺ L^?1. Copyright © 2005 Society of Chemical Industry     

Corrosion Inhibition Mechanism with Spilt Cell Technique of Rare Earth Metal on LC4 Al Alloy

A new method of studying the corrosion inhibition mechanism of rare earth metal(REM) on LC4 Al alloy with the spilt cell technique was studied. The principle and experimental method of the spilt cell technique were analyzed. By measuring the change of net-electric current between the two electrodes caused by the change of the amount of oxygen in the solution and the addition of CeCl₃, the influence of corrosive performance of CeCl₃ on LC4 super-power aluminum alloy in the 0.1 mol·L⁻¹ NaCl solution was investigated. Meanwhile, the conditional changes of pH values, CeCl₃ solution, additire and time of performance were also studied. Finally, the features of electrode surface were revealed by using SEM and X-ray energy-dispersive spectrometry (EDS). By combining these with other electric chemical techniques, such as potential-time curve, polarization curve et al.     

Corrosion protection of iron by polypyrrole coatings electrosynthesised from a surfactant solution

This work is a study of the electropolymerisation of pyrrole onto iron electrodes in the presence of sodium bis(2-ethylhexyl) sulfosuccinate in a wide pH interval. The characterisation of the films was done using electrochemical techniques, SEM/EDX and IR spectroscopy. We show that it is possible to synthesise homogeneous, adherent and very compact films in the pH range between 7 and 12 under potentiodynamic, galvanostatic and potentiostatic conditions without substrate dissolution. The effects of various parameters on electrodeposition were investigated. The new procedure for the electrochemical synthesis of polypyrrole results in improved anticorrosion properties. The inhibition is proposed to be due to the sum of a repulsion of chloride ions because AOT remains entrapped in the polymer matrix and the presence of the iron oxide. Advantages of the use of surfactants in the electropolymerisation solution are discussed.