Image encryption scheme by using iterative random phase encoding in gyrator transform domains

An image encryption is discussed based on the random phase encoding method in gyrator domains. An iterative structure of image encryption is designed for introducing more random phases to encrypt image. These random phase functions are generated by a two-dimensional chaotic mapping with the help of computer. The random phases are utilized for increasing the security of this encryption algorithm. In the chaotic mapping relation, the initial value and expression can serve as the key of algorithm. The mapping relation is considered secretly for storage and transmission in practical application in comparison to traditional algorithms. The angle parameter of gyrator transform is an additional key. Some numerical simulations have been given to validate the performance of the encryption scheme.     

三维成像中相位级次自编码的相位测量方法

提出一种相位级次自编码技术的相位测量方法.与传统的相位测量技术不同,该方法利用截断相位的微分值作为编码通道,完成对各条纹级次的编码.构造的代码序列总长度为投影条纹的周期数,每个周期作为一个码元,由相邻若干码元构成一个代码子序列.相位计算后,根据截断相位的微分信息,可以提取出各周期及其码元值,通过在设计的代码序列中进行代...     

Assessment of pulmonary artery stiffness using velocity-encoding magnetic resonance imaging: evaluation of techniques

The loss of pulmonary artery (PA) compliance has significant pathophysiological effect on the right ventricle. Noninvasive and reliable assessment of PA wall stiffness would be an essential determiner of right heart load and a clinically useful factor to assess cardiovascular risk. Two MRI techniques have been proposed for assessing PA stiffness by measuring pulse wave velocity (PWV): transit time (TT) and flow area (QA). However, no data are available that compares the two techniques and evaluates their performance, especially over a wide range of PWV values or at 3.0-T, which is the purpose of the present study. Thirty-three patients with different heart conditions were imaged using optimized high-temporal resolution and high-spatial resolution velocity-encoding MRI sequences. Statistical analysis was conducted to study intermethod, interobserver and intraobserver variabilities. The PWV measurements using TT and QA techniques showed good agreement (P>0.1). The Bland-Altman analysis showed negligible differences between the two methods (mean±S.D.=0.11±0.35 m/s, correlation coefficient r=0.94). The repeated measurements showed low interobserver and intraobserver variabilities, although the S.D. of the differences was larger in the QA technique. The mean±S.D. of the TT/QA measurement differences were −0.05±0.2/0.0±0.36 m/s and 0.02±0.26/0.02±0.39 m/s for the interobserver and intraobserver differences, respectively. In conclusion, each technique has its own advantages and disadvantages. The two techniques result in similar measurements, although the QA method is more subjective due to its dependency on operator intervention.     

面向模块化设计与制造全过程的模块编码系统

从满足模块化设计和制造全过程的需要出发，分析了模块编码的作用与目的，讨论了制定编码的一般原则以及需要进行编码的信息。根据这些信息各自的特点分析了制定编码的一般方法，并结合某机床厂加工中心类机床模块化设计编码的实例进行了验证。     

散打训练对散打运动员品格塑造的研究

散打运动是勇敢者的游戏，更是智者的博弈。目前国内的散打训练过于重视其运动的价值，而忽视了应有的对运动员武德修养的追求和意志品格的塑造，一定程度上造成散打事业误入一个偏差性的歧途。本文通过文献资料、调查、访谈等方法作出相关研究，旨在探索散打训练对散打运动员的品格的塑造的重大意义，重新诠释现代化图景下散打的精神内涵，为促提高散打运动员的综合实力和促进散打事业的全面发展提供一个新的启示。     

利用硬盘特性对软件加密、解密

提出了2种利用硬盘特性设计加密／解密软件的方法；通过在电子海图系统和模拟器上的应用，证明了方法的有效性；这种软件加密方法特点是实现简单、隐蔽性好，成本低。     

New practical tools for the implementation and use of ultrafast 2D NMR experiments

Ultrafast (UF) 2D NMR is a very promising methodology enabling the acquisition of 2D spectra in a single scan. In the last few years, the analytical performance of UF 2D NMR has been highly increased, consequently maximizing its range of applications. However, its implementation and use by non‐specialists are far from being straightforward, because of the specific acquisition and processing procedures and parameters characterizing UF NMR. To make this methodology implementable and applicable by non‐specialists, we developed a simple routine capable of translating conventional parameters (spectral widths and transmitter frequencies) into specific UF parameters (gradient and chirp pulse parameters). This macro was subsequently implemented in a Web page, which is available for external users. Although the algorithm was designed for two widely used 2D experiments, COSY and HSQC, it can easily be extended to any other pulse sequence. The robustness of this routine was verified successfully on a variety of small molecules. We believe that this tool will eliminate much of the technical difficulties related to UF 2D NMR and will make the technique accessible to a wider audience of organic and analytical chemists. Copyright © 2013 John Wiley & Sons, Ltd.     

Mutual Diffusion Driven NMR: a new approach for the analysis of mixtures by spatially resolved NMR spectroscopy

We introduce a new approach for resolving the NMR spectra of mixtures that relies on the mutual diffusion of dissolved species when a concentration gradient is established within the NMR tube. This is achieved by cooling down a biphasic mixture of triethylamine and deuterated water below its mixing temperature, where a single phase is expected. Until equilibrium is reached, a gradient of concentration, from ‘pure’ triethylamine to ‘pure’ water, establishes within the tube. The amount of time required to reach this equilibrium is controlled by the mutual diffusion coefficient of both species. Moreover, a gradient of concentration exists for each additional compound dissolved in this system, related to the partition coefficient for that compound in the original biphasic state. Using slice selective experiments, it was possible to measure these concentration gradients and use them to separate signals from all the present species. We show the results acquired for a mixture composed of n‐octanol, methanol, acetonitrile and benzene and compare them with those obtained by pulse field gradient NMR. Copyright © 2016 John Wiley & Sons, Ltd.     

庄存与和清代今文经学的复兴

今文经学自东汉迄清曾长期迁延不彰，却忽从乾嘉朴学中一飞冲天、一呜惊人，形成常州学派，僭越考据学主导地位，影响后世政治思想、文化学术和社会意识形态。何以如此？从学术自身看，这是乾嘉汉学的固有缺陷与今文经学之公羊学说长期摩挲的结果，而庄存与正是此时今文经学复兴的揭橥者。     

浅析多媒体数据压缩技术

文章介绍了数据压缩的必要性、可行性,数据压缩的概念、常用压缩方法和典型算法,并指出了数据压缩的广泛应用。