高强度304H不锈钢丝的研制

研究304H奥氏体不锈钢经过一定量拉拔、时效处理后的抗拉强度。通过试验数据得出冷拉加工的半成品钢丝强度在1640MPa时,通过适当的时效处理可获得所要求的强度,无需进行过度的冷拉加工;进行镜架配件生产时,所采用的最佳时效工艺为450℃保温3h或480℃保温1h,前者可减少配件表面的氧化,后者可有效提高生产效率。     

Effect of low-voltage electrical stimulation after dressing on color stability and water holding capacity of bovine longissimus muscle

The effect of low voltage electrical stimulation after dressing (ES) on color stability and water holding capacity (WHC) of beef was investigated. Nine Swedish red cattle were slaughtered and the left side was electrically stimulated (80 V, 35 s) approximately 30 min after stunning, whereas the other side was not treated and used as control. Color and its stability, WHC, and protein solubility were evaluated on longissimus lumborum muscles from the two sides. ES produced a brighter red color at 24h mainly by increasing the oxygenation capacity of myoglobin (P<0.01), which was attenuated by postmortem aging. ES did not affect WHC, protein solubility and color stability (P>0.05). Therefore, this technology could accelerate meat tenderization without any negative effect on commercial attributes, such as color or drip of bovine longissimus muscle.     

CR63六价铬处理剂在皮革中的应用

广东盛方化工有限公司生产了CR63六价铬处理剂(简称CR63),可有效控制皮革中六价铬的产生。本文对CR63处理皮革中Cr(VI)的条件进行优选,为CR63在皮革中的应用提供技术指导。结果表明:CR63对皮革中Cr(VI)的产生有明显的控制作用,CR63用量越大、pH值越低、温度越低,皮革中Cr(VI)含量越低;用CR63处理皮革中Cr(VI)的最佳条件为:CR63用量为1.5%、pH值为3.0、温度为30℃;经CR63最佳条件处理后,皮革中检测不出Cr(VI),在72 h老化过程中,CR63能有效防止皮革中Cr(VI)的产生。     

应用16S rDNA克隆文库技术分析陈化烟叶细菌多样性

为较全面地分析陈化烟叶的细菌多样性,利用16S rDNA基因克隆文库技术分析了产自于福建的3个等级处于不同陈化阶段的12个烟叶样品中的细菌组成.采集C/S挑、B22、X21三个等级的陈化烤烟烟叶,陈化时间分别为3、6、12、24个月.实验结果表明,烤烟烟叶在陈化过程中共存在25种细菌,γ-变形菌纲(Gamma-proteobacteria)细菌种类最丰富,含有19种细菌,α-变形菌纲(Alpha-proteobacteria)含有3种细菌,芽孢杆菌纲(Bacilli)含有2种细菌,β-变形菌纲(Beta-proteobacteria)含有1种细菌.在12个烟叶样品中,肠杆菌属(Enterobacter)在8个样品中的比例最高,假单胞菌属(Pseudomonas)在2个样品中比例最高,泛菌属(Pantoea)和克洛诺菌属(Cronobacter spp.)分别在样品B6和C3中比例最高.在陈化过程中,烤烟叶面细菌组成没有明显的变化规律.     

露天贮存对特型基酒老熟影响的研究

将一年酒基和新酒基分别放置在常规酒库和露天环境中,贮存过程中监测和分析两种环境下酒基的总酸、总酯、四大酸酯、乙醛、酒损和口感等变化,以考察贮存环境对特型酒基的影响。结果表明,在两种贮存环境下,总酸为上升趋势,总酯为下降趋势,但露天贮存环境中的总酸增幅和总酯下降幅度均较室内酒库的大,其中,贮存在露天环境中一年酒的乳酸增幅最大,接近0.6,而贮存在露天环境中的新酒乙酸增幅较大。感官结果表明,露天贮存环境下,新酒基除杂老熟速度快,在露天环境中贮存3个月时间相当于在室内贮存一年的效果。     

青稞紫米谷物饮料原淀粉复合抗老化剂配比优化研究

以蔗糖脂肪酸酯、结冷胶、六偏磷酸钠、三聚磷酸钠为组分进行复配,筛选出青稞紫米谷物饮料中原淀粉复合抗老化剂,其各组分最佳添加量为:蔗糖脂肪酸酯1.1g/L、结冷胶0.11g/L、六偏磷酸钠0.13g/L、三聚磷酸钠0.084g/L。产品货架期稳定性达10个月以上,通过感官评价、理化及微生物检测,各项指标均符合国家标准。     

并联干式电抗器故障原因分析

针对干式低抗多次在运行中起火烧毁和表面出现严重的树枝状放电故障,进行了绝缘材料的热老化性能试验、电抗器运行中温度测量、投切电抗器过电压测量以及运行电抗器解体分析试验和材料的漏电起痕等试验,揭示了干式电抗器故障的原因,并提出了反事故措施.     

Aging Behavior of xPb(Fe2/3W1/3)O3· (1 –x)Pb(Fe1/2Nb1/2)O3 Ceramic

The aging behavior of a series of lead perovskite dielectrics with the compositions x Pb(Fe_2/3W_1/3)O₃·(1 – x )Pb(Fe_1/2-Nb_1/2)O₃, where 0 ≤ x ≤ 1, and the effect of dopants were studied. Below the Curie temperature ( T _c), the capacitance and the dissipation factor (tan δ) decrease approximately linearly with logarithmic time. The aging rate depends on the temperature difference, Δ T , between the aging temperature and T _c, and on the dopant concentration, but is independent of the measurement frequency between 1 and 1000 kHz. The maximum aging rate is about 3% per decade of time for capacitance and 5% per decade for tan δ at 1 mol% dopant concentration, and increases to 6.3% for capacitance and 8.5% for tan δ at 0.7 mol% dopant concentration. These results are consistent with an aging mechanism caused by changing ferroelectric domain structure with time, as proposed for BaTiO₃.     

A Thermo-Mechanical Study of Some Epoxy Adhesives Subjected to Combined Dynamic and Static Stresses

The object of the present study was to investigate the effect of superimposed dynamic and static stresses on mechanical and thermal properties of some epoxy adhesives. It was found that combinations of shear creep and torsional oscillations, applied simultaneously to adhesive joints at temperatures within the glassy range of the adhesive, led to strengthening of the joints in shear and to an increase in the glass transition temperature of the adhesive. Similar loading stresses applied at temperatures close to the T_g of the adhesive, led to opposite effects on the above mentioned properties of the joints. The width of the glassy-rubbery transition of the adhesives increased, in the whole range of temperatures used in this study and for all epoxy compositions, as a result of subjecting the joints to superimposed dynamic and static stresses. The broadening of the glass transition was interpreted as a result of the stiffening of polymer network during the combined stressing experiments. A linear relationship was found between the area of endothermal peaks in the first DSC scan of specimens subjected prior to test to superimposed dynamic and static stresses at temperatures below T_g, and the shear strength of the joints. In agreement with this observation and with literature data, a linear relationship was revealed also between the glass transition temperature of the resins (measured in the first DSC scan) and the shear strength of the joints. Based on experimental observations and on some literature information, it was suggested that the strengthening of the joint, as well as the changes in thermal properties of the adhesives, are mainly due to physical processes, such as short-range orientation of network chains and an increase in intermolecular interaction between highly polar sites of the network. The possibility that superimposed stressing led to changes in chemical crosslinking was discussed but it seems that no such reactions occurred.