Ring head and single pole head recording performance on 3D random SOMA media

Currently, self-organized magnetic array (SOMA) is a non-oriented media, with randomly distributed easy axis directions. We investigate the recording performance of SOMA under two different head types—Ring Head (RH) and single pole head (SPH). Our results show an interesting dependence of the recorded transition pattern on the field strength of RH, where a weak RH field generates longitudinal transition pattern and a strong RH field generates a perpendicular transition pattern in the media. The SPH only generates perpendicular transition patterns and has a higher signal-to-noise ratio (SNR) than that of the RH.     

Submicellar liquid chromatography with fluorescence detection improves the analysis of naproxen in plasma and brain tissue

Rapid, simple, and sensitive submicellar liquid chromatography with fluorescence detection was developed and validated to quantify naproxen in plasma and brain samples after oral administration of Naproxen formulations. The method used tramadol as an internal standard. Different submicellar mobile phases with organic phases ranging from 40 to 60% were studied to improve the native fluorescence of the Naproxen and decrease retention times. Separation was done in a Zorbax SB C8 column (250 × 4.6 mm, 5 μm) with a mobile phase containing acidic 0.007 M sodium dodecyl sulfate/acetonitrile (50:50, v/v) at a flow rate of 1 mL/min. Detection was performed with an excitation wavelength of 280 nm and emission of 310 nm and 360 nm for internal standard and Naproxen, respectively. The method was validated by International Conference of Harmonization standards. The method is specific, accurate, and precise (relative standard deviation <3%). Limits of detection and quantification were 0.08 and 0.25 μg/mL, respectively, for biological samples. This method was applied to analyze brain/plasma ratios in mice that had received oral administrations of Naproxen micellar formulations containing 10% w/w of sodium dodecyl sulfate, Cremophor RH 40, or Tween 80. The sodium dodecyl sulfate micelles were faster and more widely distributed in the mouse brains.     

RH精炼钢中全氧量变化与操作改进

为了使钢中全氧量控制在一个适当的水平,在武钢炼钢总厂RH真空脱气装置对低碳、超低碳钢进行了脱氧净化试验.结果表明,影响全氧去除的因素按作用高低依次是出钢溶解氧水平,溶解氧与钢包渣的交互作用,钢包渣,和真空处理净化时间.通过改进工艺生产了全氧量≤10×10-6,非金属夹杂物尺寸<10μm的清洁钢水,建立了一个钢包内钢水全氧浓度随时间变化的新方程,该方程考虑了全氧的表观平衡含量及环流、扩散传质对去除氧化物夹杂速率的影响.     

RH脱碳模型的建立和测试

笔者针对无排气信息的 RH精炼装置 ,在碳氧平衡原理的基础上 ,结合工艺人员提供的经验知识 ,经过大量数据统计和仿真测试建立了 RH脱碳模型 .此文着重对其基本原理、模型主要流程、建模仿真过程和仿真测试结果进行阐述 .实践证明该模型精度优于宝钢现用模型     

RH生产X70管线钢的不同工艺研究

从冶金效果、设备性能、工艺条件等方面对LF-RH与RH-LF二次精炼法进行了全面的研究,分析了两种工艺下RH真空处理的特点,对两种工艺下管线钢中有害元素及夹杂物的控制进行了讨论.LF-RH与RH-LF工艺下生产的X70管线钢铸坯中的T[O]平均为14×10-6和19×10-6,显微夹杂物个数分别为2.48个/mm2和2.62个/mm2,达到很高的洁净度水平.LF-RH工艺铸坯中氮平均为53×10-6,RH-LF工艺条件下铸坯氮含量为平均38×10-6,为以后生产更高质量的管线钢积累了经验.     

RH真空处理GCr15轴承钢中全氧及显微夹杂物的行为研究

针对RH工艺生产轴承钢,通过现场试验研究了RH真空处理时间对钢中全氧和显微夹杂物的影响.试验结果表明,延长RH真空时间可以进一步降低钢中全氧和显微夹杂物的数量,RH脱氧主要是通过显微夹杂物的去除,全氧与显微夹杂物随时间的变化关系基本一致;真空处理25min可使钢液中全氧和显微夹杂降低约60%,比14min时多降低约13%,并得出邢钢轴承钢生产条件下,RH精炼过程钢液的表观脱氧速度系数为-0.036min-1;工艺优化后147炉轴承钢产品的平均全氧为6.7×10-6.     

RH生产超低碳钢的工艺优化

通过建立ＲＨ真空处理脱碳数学模，研究了「Ｃ」０、「Ｏ」０、吹氩流量、浸入管内径对脱碳效果的影响，模型计算结果表明，针对某厂ＲＨ处理工艺，若适当提高转炉出钢「Ｃ」，降低出钢「Ｏ」，即可满足钢中「Ｃ」的要求，又可降低脱碳终点「Ｏ」从而减少脱氧合金的消耗。     

基于CTM-RH的城市交通信号线控制

采用细胞传输模型(cell-transmission model,CTM)对城市干道交通流进行建模,并运用滚动区域法(rolling horizon,RH)对信号周期、绿信比和相位差进行优化.仿真结果令人较为满意.     

Maximal resolvable packings and minimal resolvable coverings of triples by quadruples

Determination of maximal resolvable packing number and minimal resolvable covering number is a fundamental problem in designs theory. In this article, we investigate the existence of maximal resolvable packings of triples by quadruples of order v (MRPQS(v)) and minimal resolvable coverings of triples by quadruples of order v (MRCQS(v)). We show that an MRPQS(v) (MRCQS(v)) with the number of blocks meeting the upper (lower) bound exists if and only if v≡0 (mod 4). As a byproduct, we also show that a uniformly resolvable Steiner system URS(3, {4, 6}, {r₄, r₆}, v) with r₆≤1 exists if and only if v≡0 (mod 4). All of these results are obtained by the approach of establishing a new existence result on RH(6²ⁿ) for all n≥2. © 2009 Wiley Periodicals, Inc. J Combin Designs 18: 209–223, 2010     

210 tRH精炼过程的混匀特性

以某钢厂210tRH真空精炼装置为原型,根据相似原理建立1﹕4水模型,研究了吹气量、浸入深度、真空度以及气孔堵塞对混匀时间的影响。结果表明,RH混匀时间随着吹气量的增加而呈现减小的趋势;随着浸入深度的增加先减小后增大,并存在最佳浸入深度480 mm;随真空室压力的减小而减小;随着吹气孔堵塞个数的增加先减小后增加。利用粒子成像测速技术( particle image velocimetry,PIV)测量了RH精炼过程钢包内二维流场,与数值模拟结果对比,发现钢包内的流体运动主要是从下降管到上升管的循环流动以及下降管周围的回流运动,不活跃区主要集中在渣-钢界面以下浸渍管浸入深度范围内。