带锈铸铁脱盐缓蚀后的耐蚀性能研究

在加入钼酸盐与硅酸盐复合缓蚀剂的碱性脱盐溶液中,对带锈铸铁进行脱盐缓蚀处理,对带锈铸铁处理前后的耐蚀性能进行了测试评价,并运用扫描电子显微镜和傅里叶变换红外光谱仪对锈层形貌结构进行了分析。结果表明,在该体系中脱盐缓蚀处理后,铸铁的腐蚀速度下降至5%以下,脱盐缓蚀改善了锈层结构,锈层主要组成由不稳定锈γ-FeOOH向稳定的α-FeOOH转变,锈层结合紧密,铸铁的耐蚀性能提高。     

奶奶家的土灶

我特别喜欢奶奶家的灶头,因为坐在那里,很舒服,很温暖。奶奶住在乡下老家,煮饭是用大锅煮的,而不是像我们用电饭煲。小时侯,每当奶奶要煮饭了,我都会像看电视节目一样,准时坐在小板凳上,看着奶奶点上引火柴,把它轻轻地放人灶肚,然后把落叶、柴禾放到灶膛里,看着火渐渐地旺起     

巧妇觅米好下锅 寻找源头活水来——对走出小学作文教学困境的探索

在小学语文教学中,作文教学是语文教学中的重要环节,也一直是老大难问题。如何提高小学生作文水平,一直是小学语文教师关注的问题,也是难以解决、不断探索的问题。     

耐烧碱蚀合金铸铁的研发

本课题针对制烧碱工业中设备的腐蚀问题,研制出不同稀土含量、不同镍含量的稀土Ni-Cr-Cu合金铸铁,采用光学显微镜观察材料的显微组织;用失重法测定各合金铸铁在动态、高浓度下的碱腐蚀速率;采用S-3400N型扫描电镜观察,对其耐碱腐蚀性能进行评价进而讨论稀土Ni-Cr-Cu合金铸铁在烧碱液中的耐碱腐蚀机理。结果表明:随着镍含量的增加,合金铸铁的耐蚀性能增加;适量稀土元素可以改善铸铁中石墨和碳化物的形态、分布,使石墨球化、碳化物弥散分布。     

Application of response surface methodology in medium optimization for pyruvic acid production of <Emphasis Type="Italic">Torulopsis glabrata</Emphasis> TP19 in batch fermentation

Response surface methodology （RSM） was used to optimize the fermentation medium for enhancing pyruvic acid production by Torulopsis glabrata TP19. In the first step of optimization, with Plackett-Burman design, ammonium sulfate, glucose and nicotinic acid were found to be the important factors affecting pyruvic acid production significantly. In the second step, a 23 full factorial central composite design and RSM were applied to determine the optimal concentration of each significant variable. A second-order polynomial was determined by the multiple regression analysis of the experimental data. The optimum values for the critical components were obtained as follows： ammonium sulfate 0.7498 （10.75 g/L）, glucose 0.9383 （109.38 g/L） and nicotinic acid 0.3633 （7.86 mg/L） with a predicted value of maximum pyruvic acid production of 42.2 g/L. Under the optimal conditions, the practical pyruvic acid production was 42.4 g/L. The determination coefficient （R^2） was 0.9483, which ensures adequate credibility of the model. By scaling up fermentation from flask to jar fermentor, we obtained promising results.     

Experimental and FEM Study of Coated and Uncoated Tools Used for Dry Milling of Compacted Graphite Cast Iron

Compacted graphite cast iron (CGI) has been the material for high-power diesel engines recently, but its increased strength causes poor machinability. In this study, coated and uncoated carbide tools were used in dry milling experiment and FEM simulation to study the machinability of CGI and wear behaviour of tools. The experimental and FEM simulation results show that coated tool has great advantage in dry milling of CGI. SEM and EDS analysis of tool wear indicate the wear morphology and wear mechanism. Adhesive wear is the main mechanism to cause un-coated tool wear, while abrasive wear and delamination wear are the main mechanism to cause coated tool wear. Stress and temperature distribution in FEM simulation help to understand the wear mechanism including the reason for coating peeled off.     

婴幼儿小家电

项目介绍婴幼儿小家电品种相当丰富,有电动牙刷、暖奶器、消毒器、指甲剪、音乐坐便器、婴幼儿便携式无线监视器、臭氧消毒器、电子驱蚊器、婴幼儿音乐碗、测温报警汤匙等。这些小电器都是迷你型的,小     

普通焊条低温预热修补铸铁件工艺浅析

文章分析了在一定工艺条件下,采用普通焊条进行焊接,或者配以少量的铸铁焊条焊接,使之更加方便、经济、简单,降低生产成本.     

试论大容量锅筒的制造质量问题

锅筒是锅炉重要的受压元件,是锅炉的心脏,以300MW锅筒为例,探讨和分析了300MW以工锅筒的制造质量控制.