油酸钠体系下Fe3+与白云母的作用机理研究

采用浮选溶液化学、Zeta电位、XPS等手段表征白云母表面性质,对油酸钠体系下Fe3+对白云母的作用机理进行了讨论.结果表明:在pH=6,油酸钠用量为9.20×10-4mol/L,Fe3+为7.41×10-5mol/L的条件下,白云母的回收率可达到86.40%,活化效果显著.当pH≤6时,Fe3+与白云母表面的羟基反应生成带正电的含铁络合物,其与溶液中的油酸根发生化学反应生成疏水的油酸铁物质,同时部分油酸根在白云母表面发生了静电吸附,在二者的效应下可明显提高白云母的疏水性.当6相似文献   

The effect of Al2O3 on the high‐temperature oxidation resistance of Si‐B‐C ceramic under air atmosphere

Si‐B‐C ceramics were prepared through reaction sintering, and the influence of Al₂O₃ addition on the high‐temperature (1100‐1300°C) oxidation behavior of the material under air atmosphere was studied. The erosion behavior and mechanism are determined from the measurement of weigh changes, microstructure observations, and characterization of the generated oxides on postexposure specimens. Results show that Al₂O₃ is enriched in the oxidized layer, inhibiting the volatilization of B₂O₃ and impeding the crystallization ability of oxide (cristobalite). Narrower erosion layer and less weigh change are observed with Al₂O₃. Low‐frequency Raman results reveals that with the increase in Al₂O₃, the bending vibrations of the BO₄ units and B‐O‐B stretching of the metaborate ring relative intensity are enhanced. Furthermore, high‐frequency Raman results shows that the relative proportion of high‐dimensional vibration modes Q³ and Q⁴ which result in a higher viscosity of melt and a greater resistance of oxygen diffusion are positively correlated with Al₂O₃.     

Infrared transition properties of vanadium dioxide thin films across semiconductor-metal transition

Vanadium dioxide thin films were fabricated through annealing vanadium oxide thin films deposited by dual ion beam sputtering. X-ray dif- fraction (XRD), atom force microscopy (AFM), and Fourier transform infrared spectrum (FTIR) were employed to measure the crystalline structure, surface morphology, and infrared opdcal transmittance. The phase transition properties were characterized by transmittance. The results show that the annealed vanadium oxide thin film is composed of monoclinic VO<,2>, with preferred orientation of (011). The maximum of transmittance change is beyond 65% as the temperature increases from 20 to 80℃. The reversible changes in optical transmittance against temperature were observed. The change rate of transmittance at short wavelength is higher than that at long wavelength at the same tempera- ture across semiconductor-metal phase transition. This phenomenon was discussed using diffraction effect.     

拔制方式对冷拔钢管拔制效果影响的显式动力分析

借助ANSYS软件显式动力模块建立了空拔钢管和短芯棒拔制三维有限元模型,动态模拟了两种拔制方式的整个过程,从钢管定径和轴向、周向应力分布规律角度分析了实际生产中产生问题的不同机理,并就两种拔制方式中工艺参数对拔制力的影响进行了深入研究,所得结果可为选取冷拔拔制方式提供参考,可为优化模具结构和工艺设计提供依据。     

基于电网运行数据的配网线变关系校验影响因素分析

配网线变关系是重要的基础数据,其不正确时会影响配网各项业务的开展,包括线损计算、故障抢修、停电管理等。为解决传统人工方式校验配网线变关系耗时、耗力且难以保障实时性的问题。提出了基于电网运行数据的配网线变关系校验方法,该方法包含基础方法：电压曲线相似度计算,通过相关系数大小衡量相似度大小;核心方法：三相负荷不平衡台区出口电压归算方法,通过该方法确保相关系数计算的正确性;配套方法：台区所属10kV线路判断方法。本文研究了电压损耗对线变关系校验结果的影响,结果表明：电压曲线相关系数与平均电压损耗系数和最大电压损耗系数均呈反比关系,电压损耗越大时,相关系数越小。本文所提的基于电网运行数据的配网线变关系校验方法,可以实现配网线变关系的自动校验,可以解决人工方式耗时、耗力且难以保障实时性问题。     

基于相对深度计算的图像漫游技术及其应用

提出了基于相对深度计算的TIP（Tour Into the Picture）技术．该技术根据图像的几何透视关系计算出场景的背景与前景的深度信息,实现从参考图像到TIP模型的连贯切换．通过对蜘蛛网格的修改,TIP技术实现了斜坡场景的漫游;同时将该技术运用于多个场景实现了多个场景的串联漫游．     

一个具有自适应QoS的对等系统结构框架

随着网络技术的不断发展,特别是无线环境和移动设备的引入,更多的具有不同的QoS需求的业务也将在网上得以实施,这使得传统的网络级QoS保证将不能满足用户的QoS需求,自适应QoS是在应用级解决未来无线移动网络环境下用户质量需求的较好方法。文章针对未来网络所具有的网络异质性、用户移动性、多链路覆盖、多服务覆盖等特点,提出了一个对等结构的自适应QoS模型框架,首先分析了自适应QoS基本结构、研究内容、系统特征、环境特征等,然后提出了系统的基本功能结构,并对其进行了详细讨论,最后提出了进一步研究工作的方向。     

数据可视化的研究与发展

针对数据可视化是可视化技术在大型数据库的应用中提出的新的数据分析和处理技术，该文介绍了数据可视化的概念和发展状况，然后针对大型数据集介绍了几种数据可视化技术以及它们的代表方法，并对数据可视化和科学计算可视化进行了分析和比较，最后探讨了数据可视化技术的研究发展方向。     

退火对氧敏CeO2—x薄膜结构及电子组态的影响

用射频磁控溅射法制备了ＣｅＯ２－ｘ高温氧敏薄膜，用Ｃｅ３ｄ的ＸＰＳ谱计算了Ｃｅ＾３＋浓度，研究了退火条件对氧敏ＣｅＯ２－ｘ薄膜的晶体结构及电子组态的影响，ＸＲＤ和ＡＦＭ分析表明，薄膜经９７３Ｋ至１３７３退火后，形成了ＣａＦ２型结构的ＣｅＯ２－ｘ其晶粒大小明显依赖于退火条件和膜厚，退火温度在９７３Ｋ至１１７３Ｋ时（２００）晶面是择优取向的，在１３７３退化４ｈ后，可得到热力学稳定的ＣｅＯ２－ｘ在退火前     

Screening of antibiotic susceptibility to β-lactam-induced elongation of Gram-negative bacteria based on dielectrophoresis

We demonstrate a rapid antibiotic susceptibility test (AST) based on the changes in dielectrophoretic (DEP) behaviors related to the β-lactam-induced elongation of Gram-negative bacteria (GNB) on a quadruple electrode array (QEA). The minimum inhibitory concentration (MIC) can be determined within 2 h by observing the changes in the positive-DEP frequency (pdf) and cell length of GNB under the cefazolin (CEZ) treatment. Escherichia coli and Klebsiella pneumoniae and the CEZ are used as the sample bacteria and antibiotic respectively. The bacteria became filamentous due to the inhibition of cell wall synthesis and cell division and cell lysis occurred for the higher antibiotic dose. According to the results, the pdfs of wild type bacteria decrease to hundreds of kHz and the cell length is more than 10 μm when the bacterial growth is inhibited by the CEZ treatment. In addition, the growth of wild type bacteria and drug resistant bacteria differ significantly. There is an obvious decrease in the number of wild type bacteria but not in the number of drug resistant bacteria. Thus, the drug resistance of GNB to β-lactam antibiotics can be rapidly assessed. Furthermore, the MIC determined using dielectrophoresis-based AST (d-AST) was consistent with the results of the broth dilution method. Utilizing this approach could reduce the time needed for bacteria growth from days to hours, help physicians to administer appropriate antibiotic dosages, and reduce the possibility of the occurrence of multidrug resistant (MDR) bacteria.