Selecting parameters and limits for equipment operational qualification

While operational qualification (OQ) is a well-established term within equipment qualification, users of equipment often become unsure when it comes to implementation. The biggest problem is how to select procedures and acceptance criteria. Should these be the vendor's specifications or should the users define their own limits, and, if so, how? Should all instruments of the same type have the same values or should these be optimized for each individual instrument? This article will provide an overall strategy and specific examples for HPLC on how to select procedures and acceptance limits that are based on efficient use of resources, on practicality and on the intended use of the equipment.     

HDR视频映射算法研究

基于对传统伽马指数函数、及最新Dolby PQ函数的深入研究和分析,针对采用Dolby PQ函数编码的HDR视频节目内容,提出直接将编码亮度在范围内的视频图像像素映射至电视机屏幕进行保真显示、而采用亮度压缩方式将其他高亮和低亮视频图像像素映射至电视机屏幕进行显示的HDR视频映射算法;试验证明能够将HDR视频源内PQ函数编码的像素亮度映射至电视机屏幕显示亮度的动态范围之内,保证视频源图像内容能够较真实的在电视机屏幕上显示,避免了HDR视频图像显示时出现内容丢失;以及算法且易于实现、能够快速进行商业应用.     

全息聚合材料PQ/PMMA的光学反应分析

为了探究掺杂有菲醌的聚甲基丙烯酸甲酯(PQ/PMMA)光致聚合材料的光学特性,根据该全息聚合材料基本理论以及内部的光化学反应机制与效应,通过数学方法构建内部反应模型进行仿真与拟合,分析了曝光强度、空间频率对产物、折射指数的影响以及存在的失真效应.结果表明:在给定参数下,曝光强度的最佳选择范围为60～80 mW/cm2,空间频率的相对优化的选择为1 800 lines/mm.     

基于辨识性统计特征的PQ隐密图像识别算法

提出一种基于辨识性统计特征的PQ（perturbed quantization）隐密图像识别算法。该算法根据经典PQ隐写对图像数据的更改方式,提取可有效区分该类隐密图像与其他类隐密图像的辨识性统计特征,并运用SVM（support vector machines）分类器进行分类识别。实验结果表明：本算法能够可靠地将PQ隐密图像从5类典型JPEG隐写PQ、F5、nsF5、MB1和MOD的隐密图像中识别出来;即使F5、nsF5、MB1和MOD的隐密图像不参与分类器的训练,本算法仍能有效识别PQ隐密图像。     

Study on the mechanism of dark enhancement in phenanthrenequinone-doped poly(methyl methacrylate) photopolymer for holographic recording

The dark enhancements with various exposure energies are studied in thick PQ/PMMA photopolymer. Considered the weak molecules diffusion of PQ component and the grating detuning, a new mechanism of dark reaction is proposed to explain the dark enhancement. Moreover, the influences of dark reaction on Bragg angular selectivity and grating recording are analyzed. The results are beneficial to the practical holography application.     

Relationship between aerodynamic measures of glottal efficiency and stroboscopic findings in asymptomatic singing students

Singing requires exquisite coordination between the respiratory and phonatory systems to efficiently control glottal airflow. Asymptomatic singing students underwent pulmonary function testing (PFT), videostrobolaryngoscopic examination, and measures of glottal efficiency (maximum phonation time [MPT], glottal flow rate [GFR], and phonation quotient [PQ]) performed in both a sung and spoken tone. Pulmonary function and glottal efficiency values were within reported normative data for professional singers. However, sung tones were made with significantly higher GFR and PQ and lower PQ than spoken tones. The mean GFR was not related to the degree of glottal closure (by videostrobolaryngoscopy) or underlying pulmonary support.     

积分微分方程Runge-Kutta方法的散逸性

本文针对一类积分微分方程讨论Runge-Kutta方法的散逸性,当积分项用PQ公式逼近时,证明了(k,l)-代数稳定的Runge-Kutta方法是D(l)-散逸的.     

Fabrication and characterization of poly(methyl methacrylate) photopolymer doped with 9,10-phenanthrenequinone (PQ) based derivatives for volume holographic data storage

We present our studies on the photopolymer of poly(methyl methacrylate) (PMMA) doped with 9,10-phenanthrenequinone based derivatives for volume holographic storage. By introducing different functional groups on the side-chain of 9,10-phenanthrenequinone molecule, the holographic characteristics of the material can be modified. The photoreaction involved with the holographic recording in the samples was investigated by measuring UV-Vis absorption spectrum and mass spectrum. The experimental results show that the similar behaviors were exhibited in these photopolymers. It is found that phase hologram recording in our PQ derivatives doped PMMA photopolymer involves a structure change of the quinone based molecule, which induces a strong change of the refractive index. Experimental characterizations on holographic data storage, including material sensitivity, dynamic range (M#) and bit-error-rate have been performed. We found that, by selecting appropriate functional groups, an improvement in sensitivity and M# for holographic data storage can be achieved.     

The development and application of guidance on equipment qualification of analytical instruments

 This paper describes the development of guidance for the equipment qualification (EQ) of analytical instruments. EQ is a formal process that provides documented evidence that an instrument is fit for its intended purpose and kept in a state of maintenance and calibration consistent with its use.     

DiffServ网络中一种改进的round robin公平加权调度算法

文中提出了DiffServ网络中一种改进的公平加权round robin调度算法。该算法在网络发生拥塞时,根据各优先业务 类的不同服务等级,动态地改变各优先业务类的调度权重,并同时保持了各优先业务类的相对公平性。通过仿真显 示,该算法在适度满足尽力服务类的同时,能有效处理不同业务类的突发数据,比较迅速地缓解网络的拥塞状况。