网络出版中的排版技术特点

目前大量的通讯数字流作业传送所采用的技术还是不完善的。传真技术只有160dpi的黑白分辨力,这使得要想得到某个图像好坏的真实效果非常困难,要想区分小的细节和字体就更加困难了。但是有了PDF,就可以用E-mail发送这些文件(文件可以做得足够小),并且附带解释。这些都可以作为PDF页面的一部分来描述必须要做的修改。而且,用这种PDF文件的副本     

IDENTIFICATION OF GAS-LIQUID FLOW REGIMES IN A HORIZONTAL FLOW USING NEURAL NETWORK

The knowledge of flow regimes is very important in the study of a two-phase flow system. A new flow regime identification method hased on a Probability Density Function (PDF) and a neural network is proposed in this paper. The instantaneous differential pressure signals of a horizontal flow were acquired with a differential pressure sensor.The characters of differential pressure signals for different flow regimes are analyzed with the PDF. Then, four charaeteristic parameters of the PDF curves are defined, the peak number (K1), the maximum peak value (K2), the peak position (K3) and the PDF variance (K4 ). The characteristic vectors which consist of the four characteristic parameters as the input vectors train the neural network to classify the flow regimes. Experimental results show that this novel method for identifying air water two-phase flow regimes has the advantages with a high accuracy and a fast response. The results clearly demonstrate that this new method could provide an accurate identification of flow regimes.     

生理条件下PDF对Pb2+、Cu2+、Zn2+、Ca2+的吸附研究

在生理条件下(pH2和pH7，37℃)，用马铃薯膳食纤维(PDF)对金属离了Pb^2 、Cu^2 、Zn^2 、Ca^2 进行吸附试验。结果表明，两种酸度条件下PDF对Pb^2 的吸附较大，对Cu^2 、Zn^2 的吸附较小，对Ca^2 吸附很小；PDF用量增大(减小)，吸附量(qe)减小(增大)。PDF对重金属离了的吸附表明PDF具有较好的生理活性。用作膳食纤维时应根据需求，按照已研究的用量与吸附量关系配制。其吸附作用是化学吸附与物理吸附的综合结果。PDF的疏松结构和红外光谱中较多的醛羧基团证明了这一点。吸附数据线形拟合表明物理吸附符合Ligniur单分子层吸附机理。     

在PDF工作流程中保留透明度

<正> 越来越多的设计师们开始使用PDF文件作为一个确保印刷文件万无一失的方法。现在PDF 1.4支持在PhotoShop中产生的透明度,但是输     

Simultaneous HPLC quantification of total cholesterol,tocopherols and β-carotene in Barrosã-PDO veal

A simple, rapid and sensitive procedure for the simultaneous determination of total cholesterol, tocopherols and β-carotene in meat is described. The method involves a direct saponification of the meat, a single n-hexane extraction and the analysis of the extracted compounds by normal-phase HPLC, using fluorescence (tocopherols) and UV–Vis photodiode array (cholesterol and β-carotene) detections in tandem. Rates of recovery of spiked meat samples were 93% for cholesterol, 83–86% for (α-, β- and -γ) tocopherols and 89% for β-carotene. Repeatabilities were high (CV < 6%) for all determined compounds, except for δ-tocopherol. This tocopherol, which is not usually present in meat, showed a much lower recovery percentage (73%) and repeatability (12.8%). This methodology was applied for the quantification of total cholesterol, tocopherols and β-carotene in three muscles (longissimus thoracis, longissimus lumborum and semitendinosus) of the Portuguese traditional Barrosã-PDO veal, obtained from autochthonous calves fed extensively during summer (with the least abundant green pastures) and slaughtered in early autumn (October). Barrosã-PDO veal showed median contents of total cholesterol (0.50–0.56 mg/g) and, depending on the analysed muscle, moderate to high contents of α-tocopherol (3.3–3.9 μg/g) and β-carotene (0.07–0.09 μg/g), suggesting an high sensorial and hygienic quality.     

用Plug-in实现对PDF文件的信息提取

利用Adobe Acrobat提供的编程接口编写Plug-in插件，实现对PDF文件信息的提取。     

利用Foxit Reader SDK开发PDF阅读器的研究与实现

介绍在Delphi中利用Foxit Reader SDK开发PDF阅读器,包括PDF文档的打开和关闭,调整页面大小、旋转页面、显示书签、打印和查找文本的功能。     

基于高斯和近似的扩展切片高斯混合滤波器及其在多径估计中的应用

全球卫星导航系统(Global navigation satellite system, GNSS)信号的多径估计问题实际上是条件线性状态空间模型下的状态估计问题. 根据高斯和理论提出了适用于非高斯噪声环境的扩展切片高斯混合滤波(Extension of sliced Gaussian mixture filter, ESGMF)算法. 该算法将非高斯噪声的状态概率密度函数(Probability density function, PDF)表示为高斯和的形式,将ESGMF通过一组并行的切片高斯混合滤波器(Sliced Gaussian mixture filter, SGMF)来实现.同时, 在ESGMF算法中利用粒子滤波(Particle filter, PF)中重采样的思想对成指数增加的状态预测PDF的高斯混合个体进行约简, 以提高贝叶斯推理的效率.该算法可以获得非高斯噪声下状态PDF的迭代解析表达式. 最后, 将ESGMF应用于GPS多径参数估计, 仿真结果表明, ESGMF算法的估计精度优于基于PF和扩展卡尔曼滤波(Extended Kalman filter, EKF)的算法.     

基于最大熵PDF估计的直扩系统伪码捕获结构

为了使直扩系统在未知非高斯噪声模型下准确地捕获微弱直扩信号,提出一种新的基于整数最大熵概率密度函数(probability density function,PDF)估计和局部最佳检测(locally optimal detection,LOD)相结合的相关前一维幅域处理捕获方式。通过蒙特卡洛数据仿真可以发现:在非高斯噪声的情况下,基于整数最大熵PDF估计的LOD检测器的检测性能要明显优于常规平方和(Square-Sum,SS)检测器,在信噪比为-25~0 dB时分别有2.0%~99.0%的改善。从根本上改变了常规SS检测器在非高斯噪声模型下性能急剧下降甚至无法工作的现象。     

二维条形码在机关公文管理中的应用

办公自动化系统的发展和应用,对于政府转变职能,提高办公效率起到了举足轻重的作用,但是在实际应用过程中也碰到了很多问题,其中之一就是对公文的管理。传统办公自动化系统的目标是实现办公全过程的＂无纸化＂,即把纸质文件转化为电子文件进行流转。但在目前国情下,要一步实现无纸化办公,还面临很多困难,因此政府机关不得不将纸质文件流和电子文件流并行运行,从而导致需要分发交换的纸质文件和文件的电子信息脱节。通过将条码技术引入到公文管理中,生成含有文件信息的二维条码,从而实现纸质文件和文件的电子信息完全同步。