Magnetorheological nanofinishing of BK7 glass for lens manufacturing

BK7 is a high-quality crown glass which is used where additional benefits such as temperature sensitive applications of fused silica glass are not required. Due to very low inclusion content with extremely low bubbles, BK7 glass can find its application in lens manufacturing. The present work focuses on nanofinishing of the BK7 glass specimen for ratifying its utility in practical application. A programmable logic controlled 3-axis motions are fed to the magnetorheological (MR) rotating tool for finishing the glass specimen. MR polishing fluid used for nanofinishing consists of deionized water, magnetic iron particles, and cerium oxide powder. Under the influence of magnetic field, the stiffened MR polishing fluid is assisted in reducing the surface roughness of glass up to nanolevel range. Optical properties such as transmittance, absorbance, and reflectance of finished BK7 glass are analyzed and found suitable for lens manufacturing. Results of higher surface quality with excellent finishing are obtained by the present MR finishing process. After 90?min of finishing, the surface roughness values R_a and R_q are reduced to 17 and 27?nm from the initial values of 41 and 57?nm, respectively. To study the surface morphology, scanning electron microscopy is performed on BK7 glass.     

BK Polyomavirus bkv-miR-B1-5p: A Stable Micro-RNA to Monitor Active Viral Replication after Kidney Transplantation

Background: Bkv-miR-B1-5p is a viral micro-RNA (miRNA) specifically produced during BK polyomavirus (BKPyV) replication. Recent studies have suggested using bkv-miR-B1-5p as a biomarker to monitor viral infection and predict complications in kidney transplant patients. To identify the technical limitations of this miRNA quantification in biological samples, knowledge of its stability and distribution in the extracellular compartment is necessary. Moreover, a proof of concept for using bkv-miR-B1-5p as a biomarker of active replication in chronic infection is still missing in the published literature. Methods: The stability of bkv-miR-B1-5p was evaluated in samples derived from cell cultures and in urine from BKPyV-infected kidney transplant recipients. The miRNA was quantified in different fractions of the extracellular compartment, including exosomes, and protein binding was evaluated. Finally, we developed an in vitro model for chronic culture of BKPyV clinical isolates to observe changes in the bkv-miR-B1-5p level during persistent infections. Results: Bkv-miR-B1-5p is a stable biomarker in samples from humans and in vitro experiments. Marginally associated with the exosomes, most of the circulating bkv-miR-B1-5p is bound to proteins, especially Ago2, so the miRNA quantification does not require specific exosome isolation. The bkv-miR-B1-5p level is predictable of viral infectivity, which makes it a potential specific biomarker of active BKPyV replication after kidney transplantation.     

云南某高海拔铜矿选铜起泡剂BK208工业实践

云南某铜矿地处高海拔地区,投产后经多方比对,采用以国外进口原料为主要成分的起泡剂PL-1,投产前两年原矿性质简单,含泥量少,取得的生产指标较好;随着开采的深入,矿石含泥量增多,继续使用原有起泡剂,生产指标下降幅度较大。为了提高生产指标并实现起泡剂国产化替代,进行了新型特效起泡剂BK208的工业应用试验,经过一段时间的工业试验对比,采用原起泡剂PL-1工业试验累计指标:铜精矿含Cu 23.93%、回收率84.67%;采用起泡剂BK208的累计指标:铜精矿含Cu 22.67%、回收率86.50%。采用起泡剂BK208可比采用原用起泡剂PL-1的铜回收率提高了1.83个百分点。预估每年可增经济收益超6 800万元。     

黑龙江某钼矿选矿工艺试验研究

黑龙江某钼矿钼原矿品位为0.108%,实验室采用"一段粗磨浮选抛尾,钼粗精矿两段再磨再选"选矿工艺流程,获得了较好的指标,钼精矿品位50.57%,回收率89.38%。试验研究为开发利用该类型钼矿资源,提供了技术依据。     

稀土尾矿中萤石、重晶石浮选分离研究

内蒙古某多金属矿尾矿含CaF216.67%、SiO2 32.84%、CaCO3 8.52%,属于典型的高硅高碳酸钙难处理萤石矿。本研究针对该尾矿,采用碳酸钠为活化剂、水玻璃为抑制剂、BK410为捕收剂,进行了萤石综合回收的试验研究。最后采用一次粗选、一次扫选和十次精选——中矿单独处理工艺流程,可以获得含CaF2 95.10%、回收率46.97%的高品位萤石精矿Ⅰ和含CaF2 85.35%,回收率10.12%的萤石精矿Ⅱ。     

从重选尾矿中浮选回收微细粒白钨矿试验研究

澳大利亚Watershed白钨重选尾矿含WO30.45%,其中-25μm的微细粒级金属分布率高达83.59%,且含有碳质、云母等易浮脉石,回收较为困难。针对此难选矿样进行了白钨浮选回收试验研究,最终以BK416为捕收剂,采用"预先浮选—常温浮选—加温精选"工艺,获得了WO3品位59.13%的钨精矿,选矿回收率65.72%。     

BK906及MB在铅锌矿浮选生产中的应用

陕西震奥鼎盛矿业有限公司铅锌选厂在铅锌矿浮选生产原工艺以乙硫氮、丁基黄药作为捕收剂,原药剂制度下铅精矿回收率偏低,锌精矿回收率波动大,铅锌互含率偏高,且石灰用量大,影响回水质量,并污染环境。自2011年起,原矿品位下降,黄铁矿含量上升,为了抑制黄铁矿上浮,不得不加大石灰用量。针对以上问题,企业将方铅矿捕收剂调整为弱碱性下捕收效果良好的BK906,闪锌矿捕收剂调整为MB。一年来的生产结果表明,BK906与MB配合使用,能在原矿品位下降的情况下,有效提高铅与锌的回收率,降低铅锌互含率,石灰用量由过去的10kg/t降低至5kg/t,具有良好的环保效应。     

并行前缀加法器的研究与实现

随着微处理器运算速度的大幅度提高,对快速加法器的需求也越来越高.当vLSI工艺进入深亚微米阶段的时候,很多情况下,无论是在面积还是在时序上连线都起着决定性的作用.文章基于不同的CMOS工艺,针对三种不同结构的并行前缀加法器,在不同数据宽度的情况下进行性能比较,根据深亚微米下金属互连线对加法器性能的影响,挑选出适合深亚微米工艺的加法器结构.     

某金矿石矿物加工试验研究

为了给开发某金矿提供依据,在工艺矿物学研究的基础上,对该矿石进行了可选性试验研究。采用异戊基黄药+BK903G为选金捕收剂,完成了两粗、两扫、两精闭路流程试验。对于金品位为2.87 g/t的原矿,在磨矿细度为-0.074 mm占80%的情况下,可获得金品位51.94 g/t、金回收率为82.06%的金精矿。     

随机激励下高维包装振动系统的可靠性分析

研究了两自由度包装振动系统在受高斯白噪声外激励下的可靠性.利用由随机平均法导出的关于系统的独立运动积分的随机平均方程,通过系统本身的特性以及对漂移与扩散系数作出的一些假定,给出了系统的可靠性函数以及首通损坏的条件转移概率密度函数所满足的后向柯尔莫哥洛夫方程和福克-普朗克方程,并进一步详细地讨论了其边界与可解性条件.数值结果表明,关于系统的可靠性函数以及首通损坏的条件转移概率密度函数方面的结果是比较合理的,这也表明文中的分析方法是正确的.