α,β,γ,δ-四(5-磺基噻吩)卟啉柱前衍生反相液相色谱法分离测定铜、镉和钴

以α ,β ,γ ,δ 四 (5 磺基噻吩 )卟啉为柱前衍生试剂 ,用含 1.5mmol/LH3BO3-NaOH缓冲溶液 (pH9.0 )和 5. 0× 10 - 3mol/L溴代三丁基胺 (TBA Br)的乙氰 -水 (3 0 :70 ,V/V)溶液作流动相 ,检测波长 43 0nm ,在KromasilC1 8柱上 ,同时分离测定了铜、镉和钴三种金属络合物 ,检出限 (S/N =3 )分别为 0 .2 0 ,0.16,和 0.13ng/mL。方法用于水样分析 ,结果与光度法相符。     

膜分离技术在制药工业中的应用

膜分离技术在制药工业中的应用包括生物发酵制药、中药生产和现代生物技术等．膜分离技术在抗生素、半合成抗生素、维生素和氨基酸生产中尤其常见．随着膜材料、膜组件和膜设备的不断改进，膜分离技术在制药工业中将扮演越来越重要角色．     

基于信息流动分析的动态社区发现方法

随着社交网络和微博等互联网应用的逐渐流行,其用户规模在迅速膨胀.在这些大规模网络中,社区发现可以为个性化服务推荐和产品推广提供重要依据.不同于传统的网络,这些新型网络的节点之间除了拓扑结构外,还进行频繁的信息交互.信息流动使得这些网络具有方向性和动态性等特征.传统的社区发现方法由于没有考虑到这些新的特征,并不适用于这些新型网络.在传染病动力学理论的基础上,从节点间信息流动的角度,提出一种动态社区发现方法.该方法通过对信息流动的分析来发现联系紧密、兴趣相近的节点集合,以实现动态的社区发现.在真实数据集上的实验结果表明：相对于传统的社区发现方法,所提出的方法能够更准确地发现社区,并且更能体现网络中社区的动态变化.     

A novel method for the preparation of monocarboxyl‐end‐grouped polycaprolactam with an adjustable molecular weight

A novel method was used to synthesize adjustable‐molecular‐weight polycaprolactams with monocarboxyl end groups. The reaction device and conditions are discussed. The products were characterized by Fourier transform infrared spectroscopy, ¹H‐NMR spectroscopy, high‐resolution pyrolysis gas chromatography–mass spectrometry, and wide‐angle X‐ray diffraction. The thermal properties were studied by differential scanning calorimetry and thermogravimetric analysis. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 722–727, 2004     

Numerical simulation of cutting process of the slice components cutting machine

By the use of ANSYS/LS-DYNA FEA software,numerical simulation on the cutting process of cutting plates with a reamer was carried out in the paper. The logical improvement was brought forward and the phenomenon of stress concentration was deceased by weighted analysis. The effects of different cut velocities and cutting thickness on life-spans of reamers were investigated, and the cutting parameters were optimized to satisfy the cutting precision and cutting efficiency. The study will provide a guide for the practical production.     

基于改进小波阈值函数的船用雷达回波去噪

为了对船用雷达（9GHz脉冲雷达）回波降噪,提出了基于小波阈值函数的改进方法,分析了中间阈值以及对应的阈值函数对船用雷达回波信号降噪的影响.在模拟雷达回波信号的降噪实验中,对新的阈值方法与软阈值、硬阈值、Firm阈值、Yasser阈值方法进行了比较.通过对阈值函数参数的调整,使得新的小波阈值函数得到更高的信噪比、更小的均方根误差和更大的能量比,证明了新方法的有效性;在实测雷达回波信号的降噪实验中,得到了一致的结论,证明了新方法的实用性.     

面向动用计划的车辆装备备件预测研究

针对动用计划下的车辆装备备件的消耗特点,研究了车辆装备维修备件消耗量和库存控制两个预测优化问题。考虑动用计划期内车辆装备的预防性维修和修复性维修,实现定时定程维修和自然随机故障维修下装备维修备件的消耗量的预测。在此基础上,根据备件库存检查方式的特点,建立基于定期检查策略的联合补货库存控制模型,根据模型的结构特点确定决策变量界限,并利用多类种群位置更新方式改进了果蝇优化算法。仿真结果表明,改进的果蝇优化算法具有良好的求解效率,本文所提出的优化方法可为车辆维修保障资源优化提供决策依据。     

采用自适应字典学习的InSAR降噪方法

We consider the phase noise filtering problem for interferometric synthetic aperture radar (InSAR) based on the dictionary learning technique. Due to the non-convexity of the optimization problem is difficult to solve. By using the splitting technique and employing the augmented Lagrangian framework, we obtain a relaxed nonlinear constraint optimization problem with l₁-norm regularization which can be solved efficiently by the alternating direction method of multipliers (ADMM). Specifically, we firstly train dictionaries from the InSAR complex phase data, and then reconstruct the desired complex phase image from the sparse representation. Simulation results based on simulated and measured data show that this new InSAR phase noise reduction method has a much better performance than several classical phase filtering methods in terms of residual count, mean square error (MSE) and preservation of the fringe completeness.     

Investigation on experimental method of low-impedance materials using modified Hopkinson pressure bar

To increase the detectability of split Hopkinson pressure bar (SHPB) of low-impedance materials, modifications were conducted on traditional SHPB apparatus with a PMMA tube to output transmitted signal, and weak signals were further amplified by semiconductor strain gauges. Experiments on soft rubbers and cushioning foam materials were carried out. In order to analyze the accuracy of the experimental results, the stress equilibrium issues involved in the assumptions of SHPB were investigated. First, by way of re-constructing loading process of incident wave, the stress-strain curve was obtained, along with the stress equilibrium ratio of specimen. Secondly, the influences on the accuracy of stress-strain curves were investigated through the elastic modulus comparisons. And the results illustrate that the bilinear incident wave from experiments can ensure the stress equilibrium deformation of specimen after 2 normalized times, much sooner than ramp incident waves. Moreover, it even facilitates specimen deformation with a constant strain rate. The results confirm that the detectability of the modified SHPB can be down to tens kPa with enough accuracy level.     

钢筋砼框架结构易损性评估的参数敏感性分析

运用基于位移的地震易损性概率评估方法,以梁铰破坏机制的钢筋砼框架为例,就地面峰值加速度、框架梁的几何参数和结构的材料参数在易损性评估中的敏感性展开研究.研究表明,地面峰值加速度、框架梁几何参数和钢筋极限应变的均值变化会对钢筋砼框架结构的地震易损性评估结果产生较大的影响,它们的变异系数取值也会对易损性评估结果产生一定的影响,但影响程度要小于均值的变化;砼极限应变的概率分布特征则对地震易损性的评估结果影响甚微.