38CrMoAl钢精炼过程夹杂物生成及演变规律

国内某厂冶炼38CrMoAl高铝钢时由于钢中非金属夹杂物超标而导致的钢材质量不达标情况时有发生。该钢的工业试验采用了“转炉(LD)-LF精炼(铝脱氧及合金化、高碱度渣精炼)-RH真空精炼-软吹-连铸”工艺流程。为了更好地去除钢中非金属夹杂物,采用分级分段的取样方法对工业试验进行取样,从而对钢中非金属夹杂物生成原因以及演变规律进行研究。结果表明,采用高碱度渣精炼可以有效降低夹杂物中Al₂O₃的质量分数,使之改性为钙镁铝酸盐夹杂物;RH软吹时夹杂物平均成分落在液相线内。     

氧气对茶多酚化学氧化合成茶黄素的影响

研究了O2对茶多酚化学氧化(碱性氧化和酸性氧化)形成茶黄素类物质的影响。结果表明:在接近真空、露置空气和通氧等3种不同O2含量的条件下,茶多酚碱性氧化和酸性氧化均可得到茶黄素类物质,其含量随着2种反应体系中O2含量的增加而增加,且化学氧化中儿茶素消耗的主体是EGCG、EGC、C、EC,说明O2是茶多酚化学氧化形成茶黄素的一个重要影响因素,而相关研究报道却极少涉及到关于O2在茶多酚化学氧化合成茶黄素过程所发挥的作用;另外,比较茶多酚碱性氧化法和酸性氧化法形成茶黄素的情况,前者比后者得到更多茶黄素类物质。文中还考察了O2对茶黄素化学氧化形成的影响。     

某含金铜矿石低碱度抑硫提铜试验研究

某含金铜矿石中黄铁矿天然易浮,石灰法难以抑制。通过采用低碱度工艺,实现了该矿石铜硫的有效分离。试验结果表明:在p H值为9.5条件下,采用石灰-次氯酸钙组合抑制剂,浮选闭路试验获得了较好指标,铜精矿铜品位较石灰法提高了4.49百分点,同时伴生金、银的回收率也分别提高了8.11百分点、4.77百分点。     

Reassessment of the role of gut alkalinity and detergency in insect herbivory

Previously it was reported that significant amounts of the tomato phenolic, chlorogenic acid, were oxidized in the digestive system of generalist feedersSpodoplera exigua andHelicoverpa zea. The covalent binding of the oxidized phenolic (i.e., quinone) to dietary protein exerts a strong antinutritive effect against larvae. In this study, we examined the fate of ingested chlorogenic acid in larvalManduca sexta, a leaf-feeding specialist of solanaceous plants. Significant amounts of chlorogenic acid were bound to excreted protein byM. sexta when larvae fed on tomato foliage. However, in the case ofM. sexta we suggest that the strong alkalinity and detergency of the midgut may minimize the antinutritive effects of oxidized phenolics. The solubility of tomato leaf protein is significantly greater at pH 9.7, representative of the midgut ofM. sexta, than at pH 8.0, representative of the midguts ofH. zea and S. exigua. We suggest that this increase in solubility would compensate for any loss in bioavailability of essential amino acids caused by the covalent binding of chlorogenic acid to amino acids. Furthermore, lysolecithin, a surfactant likely to contribute to the detergent properties of the midgut fluid, was shown to enhance protein solubility as well as inhibit polyphenol oxidase activity. The adaptive significance of gut alkalinity and detergency is discussed.Approved by the Director of the Arkansas Agricultural Experiment Station.     

自动电位滴定仪测定水中总碱度方法的研究

选用自动电位滴定仪的DETpH和SETpH两种模式分别对水中总碱度进行检测。DETpH模式下,高、中、低不同浓度的水样品(平均浓度为180～395mg/L)精密度测得结果RSD值分别为0.19%、0.25%、0.44%,平均回收率95.83%、96.44%,质量控制测得值为101.57mg/L与标准配置值100.00mg/L的相对误差为1.57%;SETpH模式下RSD值分别为0.15%、0.04%、0.15%,平均回收率分别为99.46%、99.38%,质量控制测得值为100.34mg/L与标准配置值100.00mg/L的相对误差为0.34%。结果表明选用自动电位滴定仪中SETpH模式对水中总碱度进行检测,精密度和准确度更好。     

油基钻井液的化学分析测试研究

为检测油基钻井液的常规性能,需要对油基钻井液的碱度、氯根含量和钙含量进行化学分析测试。为此分别提出了测试方法、试验仪器与材料、测试步骤与计算公式。测试碱度值主要是用于计算油基钻井液中未反应的过量石灰含量;测试氯根含量可用来校正蒸馏所得到的水含量,以便获得油基钻井液的固相含量;测试钙含量是用来计算油基钻井液中水相的CaCl2、NaCl矿化度。     

Effect of water hardness on the toxicity of cadmium to micro-organisms

A study was made of the effect of water hardness at different concentrations (viz. 0, 80, 120, 160, 240, 320, 400 and 480 mg l⁻¹ as CaCO₃) on the toxicity of cadmium metal (5 mg 1⁻¹) as sulphate to saprophytic and nitrifying bacteria, with respect to the rate constant (K) and ultimate biochemical oxygen demand (L) which were calculated from BOD data (15 days) using the Thomas Graphical Method. Glucose was used as a source of carbon for micro-organisms. It was observed that the toxicity of cadmium to micro-organisms (both saprophytic and nitrifying) decreased with increasing hardness and reached a maximum at 320 mg 1⁻¹ as CaCO₃ for nitrifying and 400 mg l⁻¹ as CaCO₃ for saprophytic bacteria. After these hardness levels, the ultimate BOD (L) and rate constant (K) showed a decrease. Nitrifying bacteria were found to be more sensitive to the metal as well as to its complexation with calcium or with other ions as they retained their normal activity at a lower hardness level as compared to saprophytic bacteria.     

沙沟锰矿烧结性能探讨

贵州六盘水沙沟锰矿中的锰平均含量高达33.44%,铁含量为5.99%,属于典型的软锰矿。其锰铁比为5.58,有较低的硫和磷含量使该矿成为国内为数不多的锰系合金原料。但由于其极细的粒度（〈200目的矿粉占70%以上）和极粘的物理特性又使该矿不可能直接入炉冶炼,必须进行造块处理。本文通过不同碱度和配碳量的烧结杯试验探讨沙沟锰矿的烧结性能。     

Laboratory-based investigation of the materials’ water activity and pH relative to fungal growth in internally insulated solid masonry walls

This project investigated fungal growth conditions in artificially contaminated interfaces between solid masonry and adhesive mortar for internal insulation. The project comprised several laboratory experiments: test of three fungal decontamination methods; investigation of development of fungal growth in solid masonry walls fitted with five internal insulation systems; and investigation of volatile organic compounds (VOC) diffusion through materials and whole insulation systems. One aim was to examine whether the alkaline environment (pH > 9) in the adhesive mortars could prevent fungal growth despite the water activity (a_w) in the interface exceeds the level (a_w > 0.75) commonly considered critical for fungal growth. The findings indicate that do-it-yourself decontamination solutions were inadequate for removal of fungal growth, while professional solutions were successful. However, the choice of decontamination method was of minor importance in the case of application of internal insulation with high pH adhesive mortar, as the high pH adhesive mortars were found to inactivate existing growth and prevented spore germination during the experimental period. The three tested VOCs were capable of diffusing through most of the examined products and could potentially affect the indoor air quality.     

厨房油垢清洗剂碱度测量结果的不确定度评定

根据QB/T 4348-2012《厨房油垢清洗剂》的要求及GB/T 7378-2012《表面活性剂碱度的测定滴定法》中的检测方法,依据JJF 1059.1-2012《测量不确定度评定与表示》的规定,结合具体实验过程,对厨房油垢清洗剂碱度测定结果进行不确定度评定,为建立有效的质量控制方法提供科学依据。