Effectiveness of sodium silicate as gangue depressants in iron ore slimes flotation

The recovery of iron from the screw classifier overflow slimes by direct flotation was studied. The relative effectiveness of sodium silicates with different silica-to-soda mole ratios as depressants for silica and silicate bearing minerals was investigated. Silica-to-soda mole ratio and silicate dosage were found to have significant effect on the separation efficiency. The results show that an increase of Fe content in the concentrate is observed with concomitant reduction in SiO₂ and Al₂O₃ levels when a particular type of sodium silicate at a proper dosage is used. The concentrate of 58.89wt% Fe, 4.68wt% SiO₂, and 5.28wt% Al₂O₃ with the weight recovery of 38.74% and the metal recovery of 41.13% can be obtained from the iron ore slimes with 54.44wt% Fe, 6.72wt% SiO₂, and 6.80wt% Al₂O₃, when Na₂SiO₃ with a silica-to-soda mole ratio of 2.19 is used as a depressant at a feed rate of 0.2 kg/t.     

调控流图与数据挖掘相结合的复杂过程故障诊断方法研究

采用调控流图与数据挖掘相结合的方法研究了原油蒸馏过程故障诊断问题。利用调控流图方法进行建模,通过对调控流图模型的定性仿真获得每个故障的传播途径及对每个观测变量的影响,形成故障-监测变量关系表,最后利用数据挖掘技术建立从监测变量推断故障的故障诊断模型。由于该模型结构简单,可以在生产过程中直接应用,具有速度快、判断直接的特点,在一定程度上解决了复杂过程实时故障诊断中的组合爆炸问题。     

库布齐沙漠蓝藻结皮早期发育过程净光合速率变化特征及其影响因素

将具鞘微鞘藻和爪哇伪枝藻进行原种培养和大量培养,野外接种蓝藻培养物于沙漠地表形成蓝藻结皮,每天测定蓝藻结皮生物量(用叶绿素a表示)以及结皮净光合速率的变化,并每隔2 h测定结皮净光合速率的日进程变化.结果表明,早期发育过程中蓝藻结皮生物量与结皮净光合速率均呈现同步波动性变化,且二者之间呈极显著性相关(r=0.92,P<0.0001),降雨有利于结皮生物量和净光合速率的显著提高.蓝藻结皮净光合速率的日变化进程为双峰型,最大净光合速率为3.78 mg.mg-1.h-1,最小净光合速率为-4.16 mg.mg-1.h-1.相关分析表明,对蓝藻结皮净光合速率日变化影响最大的生态因子是光合有效辐射,其次是结皮表面温度.     

A rock magnetic record of Asian cooling and aridification processes during 1.95-0.40 Ma in the southeastern Chinese Loess Plateau

The southeastern Chinese Loess Plateau is the terminal deposition area of dusts transported by the East Asian winter monsoon and the frontal area penetrated by the East Asian summer monsoon,and thus a climate sensitive region.This paper reports a rock magnetic study of a Quaternary loess-paleosol section in such a region.We tried to reconstruct the paleoclimate evolution history in the region during 1.95–0.40 Ma with magnetic parameters.The results show a general up-section decreasing trend of the ratio of HIRM/(SIRM–IRM100 mT),indicating a long-term decreasing trend of hematite coercivities in the deposits,which can be mainly related to the cooling and aridification trend of the environment in interglacial depositional area and glacial dust source region.The ratio,lf/ARM,widely used to reflect the variations of magnetic mineral grain size,manifests a long-term increasing trend of the magnetic mineral grain size and tends to indicate an overall weakening trend of the East Asian summer monsoon that controlled the pedogenic intensity.Although the regional multi-segmented paleoclimatic records revealed by several magnetic parameters in our study,the long-term Asian cooling and aridification trend inferred here is of global correlation significance.     

Combining sum-difference and auxiliary beams for adaptive monopulse in jamming

Only in the presence of sidelobe jamming(SLJ),can the conventional adaptive monopulse technique null the jamming effectively and maintain the monopulse angle estimation accuracy simultaneously.While mainlobe jamming(MLJ) exists,the mainlobe of adaptive pattern will subject to serious distortion,which results in a failure of detecting and tracking targets by monopulse technique.Therefore,a monopulse angle estimation algorithm based on combining sum-difference beam and auxiliary beam is presented.This algorithm utilizes both high gain difference beams and high gain auxiliary beams for cancelling the mainlobe jammer and multiple sidelobe jammers(SLJs) while keeping an adaptive monopulse ratio.Theoretical analysis and simulation results indicate that the serious invalidation of monopulse technique in MLJ and SLJs scenarios is resolved well,which improves the monopulse angle accuracy greatly.Furthermore,the proposed algorithm is of simple implementation and low computational complexity.     

环氧树脂胶粘剂粘结的Al2O3/Al层状复合材料

以环氧树脂胶粘剂为粘结剂,采用简单的常温模压方法,在5 MPa下经常温固化制备了Al2O3/Al层状复合陶瓷材料,考察了环氧树脂和固化剂质量比为1∶0.7、1∶0.8、1∶0.9和1∶1.0时胶粘剂的粘结强度.结果显示:当环氧树脂和固化剂的质量比为1∶0.8时,胶粘剂的粘结强度最大;在粘结接头中间添加不同表面研磨处理的铝薄片后,当进行单向研磨时环氧树脂胶粘剂的粘结强度较大.层状复合材料的显微结构显示,该复合材料的层间结合紧密;力学性能测试表明,该复合材料的抗弯强度虽比氧化铝稍低,但断裂韧性和断裂功得到了较大的提高,这得益于裂纹扩展过程中形成的多裂纹特征.     

烟草多酚提取工艺优化及成分定性分析

采用微波辅助技术提取烟草多酚,利用高效液相色谱-光电二级管阵列检测器-质谱联用技术(HPLC-PDA-MS)对烟草多酚主要组分进行定性分析.研究了微波功率、甲醇用量、提取时间和料液比对烟草多酚得率的影响.经响应面优化确定烟草多酚的微波提取条件为:53%甲醇,料液比为1∶11,微波功率为560 W,提取时间为70 s,在此条件下总多酚得率为22.38 mg/g(干重).HPLC-PDA-MS测定表明,烟草多酚的主要组分为绿原酸和芸香苷.     

基于专家系统的变电站监控信号智能处理系统

为了减轻变电站运行人员的工作负担,辅助故障快速判断,提高运行人员技术水平,在深入总结变电站异常和故障类型的基础上,构建了一个多层次的故障推理模型,结合网络拓扑技术,实现了一个基于专家系统的变电站监控信号智能处理系统.系统的监控信号分析处理功能全面,快速定位机制确保值班员能迅速确定故障信息所在间隔,能准确报告变电站主要故障,并结合专家知识库出具故障报告,提供故障处理指导.系统具备故障模拟及培训功能.该系统在变电站实际应用中取得了良好的效果.     

基于555定时器的声光双控照明灯设计

本文提出一种基于555定时器的声光双控照明电路设计,该设计廉价可靠,可广泛应用于普通场所。     

Cell-specific ATP7A transport sustains copper-dependent tyrosinase activity in melanosomes

Copper is a cofactor for many cellular enzymes and transporters. It can be loaded onto secreted and endomembrane cuproproteins by translocation from the cytosol into membrane-bound organelles by ATP7A or ATP7B transporters, the genes for which are mutated in the copper imbalance syndromes Menkes disease and Wilson disease, respectively. Endomembrane cuproproteins are thought to incorporate copper stably on transit through the trans-Golgi network, in which ATP7A accumulates by dynamic cycling through early endocytic compartments. Here we show that the pigment-cell-specific cuproenzyme tyrosinase acquires copper only transiently and inefficiently within the trans-Golgi network of mouse melanocytes. To catalyse melanin synthesis, tyrosinase is subsequently reloaded with copper within specialized organelles called melanosomes. Copper is supplied to melanosomes by ATP7A, a cohort of which localizes to melanosomes in a biogenesis of lysosome-related organelles complex-1 (BLOC-1)-dependent manner. These results indicate that cell-type-specific localization of a metal transporter is required to sustain metallation of an endomembrane cuproenzyme, providing a mechanism for exquisite spatial control of metalloenzyme activity. Moreover, because BLOC-1 subunits are mutated in subtypes of the genetic disease Hermansky-Pudlak syndrome, these results also show that defects in copper transporter localization contribute to hypopigmentation, and hence perhaps other systemic defects, in Hermansky-Pudlak syndrome.