镜铁山铁矿低贫化放矿的初步实践

镜铁山铁矿在Ⅱ号矿体进行了低贫化放矿的现场试验。初步实践表明，试验取得了较好的技术经济指标，在矿石回采率基本不变的条件下可大幅度降低岩石混入率，提高出矿品位。低贫化放矿方法已在全矿推广应用，获得了较好的经济效益。     

浅谈矿山企业矿石损失与贫化指标的确定

论述了矿山企业矿石损失、贫化的含义及造成损失和贫化的原因，给出了不同情况下矿石损失与贫化指标的计算公式。     

粗苯中三苯含量快速定量分析方法的研究

通过气质联用仪(GC-MS)对粗苯中的有机组分进行定性分析,使用配有氢火焰离子检测器(FID)的气相色谱仪对苯、甲苯、二甲苯(三苯)进行定量的研究。     

在镁表面激光熔覆镁铝合金的研究

这项研究用激光熔覆的方法在纯镁基底上获得了三种成分的镁铝非平衡合金,它们在组织组成、各组分相对量、固溶度等诸方面均不同于相应的平衡合金.在富镁合金中和富铝合金的界面上生成了共晶组织,富铝合金中形成了微晶结构.研究表明了工艺参数对显微组织的影响.腐蚀研究表明富铝合金的腐蚀速率比纯镁的低两个数量级.     

二元非理想溶液过量体积的测定与研究

采用改进的倾斜式稀释膨胀溶液在298.15K 测定液体苯(1)——环已烷(2)的过量体积,并与文献值比较证明倾斜式稀释膨胀计测得数据可靠。又对未见报导的二甲苯(1)——环已烷(2)溶液在299.15K、288.15K 测定不同浓度下的摩尔过量体积数值,并用 Redich—Kister 方程对全浓度范围内的摩尔过量体积进行关联计算,从而为溶液热力学提供有价值的热力学数据。     

进化神经网络在激光熔覆成形中的应用研究

在激光熔覆成形金属制件工艺中,熔覆层稀释率大小对成形制件的性能以及后续工序的处理有至关重要的影响。设计了基于进化神经网络的学习算法,建立了熔覆层稀释率随工艺参数变化的预测模型,该模型结合了基因遗传算法的全局搜索能力和BP神经网络良好的局部性质。实验和模拟结果表明,基于进化计算的神经网络不仅可以克服单纯使用BP神经网络易陷入局部极小值等问题,而且预测精度较高,具有一定的实用价值。     

Determination of potent odorants in apple by headspace gas dilution analysis

Gas chromatography-olfactometry with headspace gas dilution analysis was used to evaluate the odor potencies of volatile compounds in Fuji apple. To improve the resolution of volatile compounds, the dilution analysis was conducted on two types of capillary columns with different polarities. Thirty three and 20 compounds were identified on DB-WAX and DB-5 columns, respectively. Methyl 2-methylbutanoate, isobutyl acetate, ethyl butanoate, ethyl 2-methylbutanoate, isopentyl formate, butyl acetate and hexyl acetate as well as hexanal were important odor contributors in the headspace gas of apple on the basis of high Flavor Dilution (FD) factors. Threshold values-in-air of these compounds were also estimated from the relationships between their FD factors and concentrations. Methyl 2-methylbutanoate and ethyl 2-methylbutanote were considered as the most potent odorants because of their lowest threshold values. In addition, the threshold values-in-air of isopentyl formate, isopentyl acetate and butyl isobutanoate, which have never been reported, were estimated at 0.149, 1.95 and 0.00607 μl/l, respectively.     

Contamination due to process gases

A survey is given of the BOC Group technical research programs, whose purpose is to relate purity in gas processing to ULSI device parameters. Results from the following research programs are presented: how inert gas purity affects the Ti silicide for IGFET metallization; the effects of argon versus nitrogen used in silicon gate oxidation process steps; and preliminary work on a new gas analytical tool, Atmospheric Pressure Ionization Mass Spectrometry (APIMS), which allows measurement of sub ppb impurity levels in processing gases.     

Analysis of multiple indicator dilution curves for estimation of renal tubular transport parameters

A model is developed to estimate the renal tubular secretory parameters by the multiple indicator dilution (MID) technique. The model allows the calculation of influx (from plasma space to tubular cell), efflux (from tubular cell to plasma space) and sequestration (from tubular cell to luminal side) rate constants. A program using the MID-statistical analysis with least squares fitting (SALS) system for the estimation of these parameters is presented. A trapezoid rule and a non-linear least squares regression were used to carry out definite integrals of cubic spline function and least squares fitting, respectively. The system presented seems to be useful for the precise and rapid estimation of the tubular secretory rate constants.     

Can He3 - He4 dilution refrigerators operate aboard spacecraft?

Cooling to temperatures in the millikelvin range could be beneficial as a means of reducing noise and increasing sensitivity of instruments in certain experiments and measurements that are being considered for future space missions. The possibility of using a He³ - He⁴ dilution refrigerator for that purpose is explored in this paper. Calculations reported here indicate that electrostriction can be substituted for gravity as a practical means of achieving phase separation with well-defined interfaces in mixing chambers of dilution refrigerators operating aboard spacecraft.