微弧氧化溶液pH值对ZM5膜层性能研究

目的 扩大镁合金的应用范围，增强其耐蚀性。方法 取镁合金ZM5为研究对象，利用微弧氧化技术对其表面进行改性处理。首先，对ZM5合金基体进行前处理；然后，在不同pH值的电解质溶液中，通过微弧氧化的方式在ZM5表面原位生长一层微弧氧化陶瓷膜层；最后，利用扫描电镜、X射线衍射、电化学测试等表征技术，系统研究微弧氧化处理对ZM5合金表面形貌、元素组成、微观结构及性能的影响规律。结果 通过调节溶液的pH，能够有效制备出表面连续而且完整的微弧氧化膜层，在pH=11条件下，制备的膜层具有较好的耐蚀性，能显著降低其腐蚀电流密度，膜层的厚度达到35.1 μm，微弧氧化表面处理技术能够显著提高镁合金的表面硬度，硬度最大为582HV。结论 改变溶液pH能够使膜层具有较高的耐蚀性和有效提高表面硬度，为进一步扩大镁合金在军用装备上的应用提供可能性。     

优化多孔蜂窝状硅镁胶的制备及其对弱酸性红的吸附性能

为了研究开发经济、高吸附量、可再生的吸附剂,以Na₂SiO₃、MgCl₂为原料,通过溶胶-凝胶法制备出一系列优化蜂窝状硅镁胶,并分析制备硅镁胶的最佳焙烧条件,采用热重分析(TG)、红外光谱(FT-IR)、X射线衍射光谱(XRD)、比表面及孔隙度分析、电镜扫描(SEM)等手段对硅镁胶进行结构表征和性质测定,研究硅镁胶对印染废水中弱酸性红的吸附行为. 结果表明:经500 ℃焙烧4 h后镁硅配比〔n(Mg2+)∶n(SO2-₃)〕为3∶1的硅镁胶对弱酸性红具有最好的吸附效果,硅镁胶对弱酸性红的吸附符合Langmuir模型,吸附过程符合伪二级动力学模型,在吸附温度为25 ℃、投加量为0.5 g/L、ρ(弱酸性红)初始值为200 mg/L时,硅镁胶对弱酸性红的饱和吸附量可达到199.51 mg/g,脱除率达到99.34%;经过5次再生之后对弱酸性红依然具有较高的吸附量,可达到192.12 mg/g,脱除率为95.60%. 研究显示,以Na₂SiO₃、MgCl₂为原料制备的优化多孔蜂窝状硅镁胶对弱酸性红具备良好的吸附性能,并且具有较好的再生能力,是一种廉价高效的吸附材料.      

Experimental study on the suppression of gas explosion using the gas–solid suppressant of CO2/ABC powder

Gas explosion is the leading accident in underground coal mining in China. Using the self-improved 20 L spherical experimental system, the impacts of 8% CO₂, ABC powder at various concentrations and mixture of them on the suppression of mine gas explosion were investigated. The results indicate that cooperative synergism exists between ABC powder and CO₂. Their combination has a better effect than each of the two components acting alone, especially for the gas of larger concentration. When 0.25 g/L ABC powder was mixed with 8% CO₂, the explosion limits were reduced by about 55%, the time to reach the peak explosion pressure was prolonged 3.56 times on average. Meanwhile, the maximum explosion pressure declined on an average of 59.4% and the maximum explosion overpressure rising rate decreased on an average of 91.1%. A combination of 0.20 g/L ABC powder and 8% CO₂ completely suppressed 11% gas explosion. The explosion suppression mechanism of CO₂ and ABC powder were probed theoretically. CO₂ plays a key part in the whole explosion processes, and it can effectively suppress the forward reaction between gas and oxygen. While it is during the middle-later period of explosion processes that ABC powder plays a critical role. The particles decomposed from heated ABC powder such as nitrogen and phosphor will react with free radicals rapidly. Besides, atoms as N, P are capable of participating in chain reaction and reacting with active groups, significantly suppressing the gas explosion.     

镁离子对氧化亚铁硫杆菌生物合成次生铁矿物的影响

通过摇瓶实验,在Mg2+分别为48,4.8mg/L,其他元素组成与9K液体培养基一致的体系中,采用氧化亚铁硫杆菌A. ferrooxidans催化合成次生铁矿物.考察了Mg2+含量对生物合成次生铁矿物体系pH值、氧化还原电位(ORP)、Fe2+氧化率、总Fe沉淀率、次生铁矿物矿相及矿物晶体尺寸的影响.结果表明,经过48h培养,Mg2+浓度为48,4.8mg/L生物成矿体系pH值分别从原来的2.50降低至2.30,2.19,ORP分别从初始259mV增加至269mV,276mV.两体系Fe2+氧化率培养至第48h均达到100%,然而两体系总Fe沉淀率及矿物形态及却不尽相同.Mg2+浓度为48mg/L生物成矿体系,总Fe沉淀率为23.7%,次生矿物紧密粘附于三角瓶底部.而Mg2+浓度为4.8mg/L生物成矿体系,总Fe沉淀率达到32.2%,次生矿物却均匀分散于溶液中.两体系合成次生铁矿物均为黄铁矾与施氏矿物共存的混合物,Mg2+含量4.8mg/L体系合成黄铁矾单个晶体长度(~1.60μm)约为Mg2+含量48mg/L体系的1.2倍.     

聚磷腈/氢氧化镁协同阻燃聚丙烯的研究

为改善氢氧化镁阻燃聚丙烯的力学和阻燃性能,合成一种新型氢氧化镁协同阻燃试剂聚二(乙醇)磷腈,并制备聚磷腈/氢氧化镁复合阻燃材料。用红外光谱(IR)和氢核磁共振仪(H-NMR)研究阻燃剂聚二(乙醇)磷腈的化学结构,并利用扫描电子显微镜(SEM)、电子万能试验机和氧指数测定仪,研究聚磷腈/氢氧化镁复合阻燃材料添加量对聚丙烯的结构、力学性能和阻燃性能的影响。研究结果表明:这种复合阻燃材料具有较好的阻燃效果,且能使聚丙烯力学性能有一定程度的提高。这些结果主要归功于聚磷腈不仅起到协同阻燃作用,而且还作为氢氧化镁的分散剂,提高了氢氧化镁粒子在聚丙烯中的分散度及界面结合力。     

铝粉超细化对KClO3/Al/S配方药剂特性的影响

为研究铝粉超细化后对烟火药剂性能的影响,将普通铝粉和纳米铝粉分别与氯酸钾、硫黄粉按照零氧平衡的同一配比(17%Al+63%KClO3+20%S)配制成烟火药剂,分别用0#样品和1#样品表示。用ARC、WL-1型落锤仪和MGY-1型摆式摩擦感度仪等试验装置从热安全性、撞击感度和摩擦感度等方面进行对比试验。结果表明,与含普通铝粉的0#样品相比,含纳米铝粉的1#烟火药剂热分解的初始反应温度明显降低(118.67℃<123.3℃),反应到达最大温升速率所需的时间明显延长(4.94min>0.13 min),反应所能达到的最高压力明显降低(2.77 MPa/g<3.14 MPa/g),反应动力学因子明显降低(361.85 kJ/mol<409.41 kJ/mol),撞击感度明显下降(12%<100%)。这说明铝粉粒径对药剂的性能有一定的影响。纳米铝粉的加入在加速烟火药剂反应进程的同时,可有效降低其反应的激烈程度、压力危险性和撞击危险性,即铝粉超细化后可以有效改善烟火药剂的性能,提高其安全性。     

粉料无尘装车技术的应用及发展

传统除尘器卸灰、输灰系统存在工艺繁杂、能耗大、输送速度慢、设备故障率高、系统难以维护及二次扬尘等问题,采用新型粉料无尘装车技术可有效简化工艺,提高生产速度和系统运行、维护可靠性,很大程度上减少能耗并彻底根除二次扬尘。     

14C-Ethion residues in soybean seeds: metabolic pathway,effect of processing,bioavailability, toxicity and protective action of artichoke leaf powder towards rats

The metabolic fate of ethion labeled with ¹⁴C-at the ethyl ester groups in soybean seeds following topical application to leaves was studied. Chromatographic analysis of soybean oil revealed the presence of the parent compound together with four metabolites which were identified as ethion monooxon, ethion dioxon, O-ethyl phosphorothioate and O,O-diethyl phosphorothioate. The effect of processing on ethion residues in soybean oil was investigated. The refined oil contained small amounts of the ¹⁴C-residues originally present (37.5%). Upon feeding rats with the cake containing ethion bound residues, a substantial amount of ¹⁴C-residues was eliminated in the urine (73%), and about 6% excreted with the feces. About 5% of the radioactive residues were distributed among various organs. Mature male Wistar rats were fed on soybean seeds containing ethion residues (1.93 ppm), and on artichoke leaves powder (1% W/W) for four weeks. At the end of the experimental period, the ethion-treated group had a significantly higher alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) activity, urea, creatinine, total cholesterol (TC), triglycerides (TG), and very low density lipoprotein (VLDL) levels. The ethion-treated rats also had a lower total serum protein and albumin levels, as well as acetyl cholinesterase (AChE), catalase (CAT), and glutathione-S-transferase (GST) activity as compared with controls. Moreover, concomitant treatment with artichoke leaf powder improved, at least partially, all the biochemical parameters that were altered by ethion.     

Environmental protection by utilization of the slag from magnesium production in building materials

This paper presents the results of research on the utilization of slag produced as the waste material of metallic magnesium production. This material is a fine powder with a high magnesium content. The characterization of slag was performed by XRD, DTA and TG analysis. Chemical composition and mechanical properties of slag were also determined. By using a mixture this slag and limestone aggregate, it is possible to obtain dry mortar which, mixed with water, gives a material fully satisfying for plastering mortar. By adding inorganic pigments (Fe₂O₃, Ca₂O3, etc.) decorative mortars are obtained, and when they are spread over the foundation made of brick or concrete, they retain their colour on the entire coating and surface of the mortar.