提高选钼技术经济指标的探讨

介绍了德兴铜矿提高铜钼混合精矿用品位的几项科研成果以及在生产中应用情况。采用充氮新工艺、充填式浮选柱新设备的试验结果表明不仅能提高铜钼分选指标而且可显著降低生产成本。     

Investigation of the relation between surface roughness and friction properties of polyester fabrics after abrasion

This paper focused on the investigation of surface roughness and friction properties of polyester fabrics after abrasion. Experiments were performed on polyester woven fabrics produced from the same yarns in warp and weft directions but with different constructional properties. Surface roughness parameters of amplitude, spacing and hybrid, along with static and kinetic coefficients of friction were measured before and after multiple abrasion cycles. Abrasion was used in order to change the surface characteristic (peak and valley heights and depths and their distributions) in such a way by forming ruptured fiber ends under the control of abrasion. Measurements were made along warp, weft, and diagonal directions. The results showed that roughness parameters decreased numerically as abrasion cycles increased and as ruptured fiber ends formed. Static and kinetic coefficients of friction changed in different manners when measurements were performed along warp and weft directions. It was concluded that initial and resultant peak heights and valley depths together with their distribution on fabric surface govern roughness and friction properties of surfaces in opposite ways. Roughness parameters of skewness and kurtosis could be further considered in the research of friction properties of textile surfaces.     

Hydrogen transport in solution-treated and pre-strained austenitic stainless steels and its role in hydrogen-enhanced fatigue crack growth

Hydrogen solubility and diffusion in Type 304, 316L and 310S austenitic stainless steels exposed to high-pressure hydrogen gas has been investigated. The effects of absorbed hydrogen and strain-induced martensite on fatigue crack growth behaviour of the former two steels have also been measured. In the pressure range 10–84 MPa, the hydrogen permeation of the stainless steels could be successfully quantified using Sieverts' law modified by using hydrogen fugacity and Fick's law. For the austenitic stainless steels, hydrogen diffusivity was enhanced with an increase in strain-induced martensite. The introduction of dislocation and other lattice defects by pre-straining increased the hydrogen concentration of the austenite, without affecting diffusivity. It has been shown that the coupled effect of strain-induced martensite and exposure to hydrogen increased the growth rate of fatigue cracks.     

Effect of ultrafine grain refinement on hydrogen embrittlement of metastable austenitic stainless steel

Micro-tensile tests were performed on high-pressure-torsion-processed specimens of type 304 steel with grain sizes in the range of 0.1–0.5 μm to clarify the effect of ultrafine grain refinement on the hydrogen embrittlement (HE) of metastable austenitic steel. The ultrafine-grained (UFG) specimens with average grain sizes < ～0.4 μm exhibited a limited uniform elongation followed by a steady-stress regime in the stress–strain curves, which was attributed to a martensitic transformation. A high yield stress and a moderate elongation to failure were attained for the UFG specimens with an average grain size of ～0.5 μm in the uncharged state. Hall–Petch relationships well hold between the yield stress and the average grain size for each uncharged and hydrogen-charged specimen. Hydrogen charging increased the friction stress by 40% but did not change the Hall–Petch coefficient. Hydrogen-induced ductility loss was mitigated by ultrafine grain refinement. Ductility loss due to hydrogen charging manifested in the local deformation after a martensitic transformation. This indicates that hydrogen does not significantly affect the martensitic transformation, but shortens the subsequent local deformation process.     

Contents of eight harmful elements in baby toys and their migration tests

Levels of eight harmful elements, i.e., antimony, arsenic, barium, cadmium, chromium, lead, mercury and selenium, were investigated in 45 baby toys and 10 paints, which were mainly made of polyvinyl chloride. All samples contained barium at levels of 0.3-3,700 mg/kg, several samples contained cadmium (0.2-26 mg/kg), chromium (0.5-280 mg/kg) and lead (1.5-1,300 mg/kg), and one sample contained antimony (5.3 mg/kg). They might have been used as colorants of the toy materials and paints. They were then evaluated using the migration test of ISO 8124-3, in which samples were ground up, and then soaked in 0.07 mol/L HCl at 37 degrees C for two hours. Barium, cadmium, chromium and lead migrated from some of the samples, but at levels lower than the migration limits required by ISO 8124-3. Compared with the Japanese official method, the ISO method resulted in higher migration, but there are significant differences in the migration limits, test method, and so on between them. Further investigation is needed in this area.     

Surface roughness properties of wool woven fabrics after abrasion

Effects of abrasion on surface roughness properties together with appearance of woven wool fabrics have been investigated. The effects of weft yarn count, weft yarn density, and weave pattern on fabric surface roughness after abrasion were researched. Surface roughness values of control fabric (not abraded) and abraded fabrics after four different abrasion cycles were discussed according to different fabric constructional parameters. It was observed that the greatest decreases in surface roughness values after abrasion were observed in loose fabric structures which had the highest initial fabric surface roughness values (coarse yarn, low yarn density, and low yarn intersection). The results showed that change of roughness properties of wool fabric surfaces after abrasion depends on the initial surface roughness values and on the amount of contact area of fabrics based on the fabric constructional parameters.     

氰化工艺过程中金属存量计算方法探讨

为搞好金属平衡，减少理论与实际差值，依据某黄金矿山氰化工艺流程特点，对脱药用单层浓密切、漫出槽、三层洗涤浓密机三个作业中的金属存量的计算方法进行了探讨。     

电子轨道衡转向架计量控制程序的应用

本文论述了转向架计量电子轨道的数据处理过程.对车皮过衡速度、车型判断、重量计算、采集数据的存贮给出了实现方法.此程序适用于绝大多数四轴车以转向架方式过衡.