A digital secure image communication scheme based on the chaotic Chebyshev map

In this paper, a simple image secure communication scheme based on the chaotic Chebyshev map and chaos synchronization is proposed. The scheme relies on the excellent correlation property of chaotic sequences, which is very desirable for secure image communication. The results obtained by computer simulation indicate that the transmitted source image can be correctly and reliably recovered using the proposed scheme, even through a noisy channel. Notably, the scheme possesses relatively high security and can be easily implemented. Moreover, the quality of the recovered image is satisfactory, quantified by such common criteria as the bit‐error rate performance. Copyright © 2004 John Wiley & Sons, Ltd.     

Dreamweaver UltraDev环境下实现数据库的动态链接

简要论述了如何在Dreamweaver UltraDev环境下实现对已有的Access或Excel数据库的动态链接的操作。在Dreamweaver UltraDev环境下，实现对企业、事业单位原有Access或Excel数据库的动态链接，可以在很短的时间内开发出符合单位实际情况的信息管理系统，并且可以使这类已经创建好的数据信息，不加任何修改地与外部进行交流，实现资源共享。将此系统以主页的形式链入Internet，可以实现开放式管理体系。     

稀土元素的分离技术

对目前稀土元素分离过程中几种常用的分离技术进行了综述，使用得较多的仍然是溶剂萃取法和离子交换法，而且新方法也在不断地出现。     

装配式贝雷桁架门机设计

本文就装配式贝雷桁架门机的设计要点作了简要的介绍,并对其拼装的技术质量提出要求。     

铁磁偶合的Gd（Ⅲ）Cu（Ⅱ）配合物──组装分子基铁磁体的一种重要元件

铁磁偶合的Ｇｄ（Ⅲ）Ｃｕ（Ⅱ）配合物──组装分子基铁磁体的一种重要元件缪明明，廖代正，王耕霖（南开大学化学系天津３０００７１）摘要分子基磁体的设计是自然界向化学家挑战的一个热点课题。铁磁偶合的Ｇｄ（Ⅲ）Ｃｕ（Ⅱ）配合物是组装分子基磁体的一种重要元件。...     

声表面波32位MSK抽头延迟线

介绍了扩频通信有效的ＭＳＫ信号特点及声表面波ＭＳＫ抽头延迟线构成方式，给出了声表面波３２位ＭＳＫ抽头延迟线的实验结果。     

Clinical and experimental observation of xilixin granule combined with radiotherapy in treating malignant-tumors

Thirty six patients of pulmonary or nasopharyngeal carcinoma were treated with Xilixin granule (XLXG) combined with radiotherapy and compared their efficacy with that of 31 patients treated by Zhenqi Fuzheng granule combined with radiotherapy for control. Results showed that the symptoms of Yin Deficiency syndrome in treated group were obviously improved, the leucocyte decreased by 5.6%, while in control group it reached 25.8%, the 3 year survival rate was significantly higher in treated group (75.0%) than that in control group (51.6%). Animal experiment revealed that XLXG had the effects of tumor inhibition, it could increase white blood cells, platelets and hemoglobin of patients, especially in using large dosage. These results suggested that XLXG have some protective effect against radiotherapeutic damage in patients with malignant tumor.     

中东原油馏分油加氢生产润滑油基础油

分析了中东原油馏分油的基本性质，综述了加氢裂化、加氢处理、加氢脱蜡、加氢精制及组合工艺的工业应用情况，探讨了由中东原油馏分油生产润滑油基础油应注意的问题，提出了适合炼油厂生产润滑油的建议。     

Real time frequency domain fiberoptic temperature sensor

The excited state phosphorescence lifetime of alexandrite crystals is used to monitor temperature in the physiological range from 15-45°C with precision and accuracy of 0.2°C. A 500-μm cubic alexandrite crystal bounded to the distal end of an optical fiber of similar core dimensions is excited with pulsed Ne-He laser light. This apparatus uses a sampler for data acquisition and frequency domain methods for data fitting. The instrument amplifies the AC components of the detector output and band limits the signal to 12.5 kHz. The fundamental frequency of the excitation is set to 195.13 Hz to obtain 64 harmonics. This band limited signal is sampled and averaged over few hundred cycles in the time domain. The frequency domain representation of the data is obtained by employing fast Fourier transform algorithms. The phase delay and the modulation ratio of each sampled harmonic are then computed. Five to 50 values of the phase and modulations are averaged before computing the sensor lifetime. The instrument is capable of measuring precise and accurate excited state lifetimes from subpicowatt luminescent signals in plastic optical fibers. A least squares fit yields the lifetimes of single exponentials. A component of zero lifetime is introduced to account for the backscatter excitation seen by the photodetector leaking through optical interference filters. The phosphorescence lifetimes measured reproducibly to about three parts in a thousand are used to monitor physiological temperature. Temperatures are computed employing empirical polynomials. The system drift is negligible over 15 h of continuous operation. The instrumentation and methods allow 1.3-s update times and 30-s full response times     

一个全数字化交流永磁伺服系统

介绍了开发的全数字交流伺服系统的组成、基本原理及软、硬件结构。通过与模拟交流伺服系统的比较，说明了全数字交流伺服系统可编程能力强、系统稳定性好、系统性能提高等特点。