The notion of nature in chemistry

If nature is by definition the object of the natural sciences, then the dichotomy ‘natural’ versus ‘chemical’, held by both chemists and nonchemists, suggests an idiosyncrasy of chemistry. The first part of the paper presents a selective historical analysis of the main notions of nature in chemistry, as developed in early Christian views of chemical crafts, alchemy, iatrochemistry, mechanical philosophy, organic chemistry, and contemporary drug research. I argue that the dichotomy as well as quasi-moral judgments of chemistry have been based on static and teleological notions of nature throughout history and that chemists, unlike physicists, have neglected the dynamic notion of nature. The second part provides a philosophical criticism of the former notions and argues for the latter as well as for an explicit discourse about values in chemistry.     

SIAR在强干扰背景下目标的检测与跟踪(一)

本文首先讨论稀布阵综合脉冲孔径雷达（ＳＩＡＲ）的抗干扰性能，表明该雷达在抗干扰方面手段丰富，抗干扰能力强。然后介绍自适应置零处理在ＳＩＡＲ中的应用。计算机模拟结果表明：ＳＩＡＲ可以在强干扰背景下对目标进行有效的检测。     

三孔径SAR-MTI系统的性能分析

具体分析了用于检测和定位运动目标的三端口SAR -MTI系统工作原理及性能。着重讨论了各种误差对检测和定位运动目标的影响 ,并对假设的雷达系统进行了计算机仿真。结果表明 ,在存在各种系统误差的条件下 ,系统仍具有良好的性能。由于是开环处理 ,这种系统具有较强的环境适应能力 ,同时处理所需的计算量和硬件设备量也不大 ,因此这种方法容易在工程上实现。     

基于加权子空间拟合的干涉相位估计方法

提出复合导向矢量的概念,并通过对测量的信号子空间与复合导向矢量张成的子空间进行拟和,推导出一种基于加权子空间拟合思想的干涉相位估计方法,该方法具有自适应图像配准和降低相位噪声功能,因而可以在图像配准精度很差(可以允许达到一个分辨单元)的条件下准确地估计相应像素间的干涉相位.仿真和实验数据表明估计结果优于基于子空间投影方法的估计结果.     

SAR images classification method based on Dempster-Shafer theory and kernel estimate

To study the scene classification in the Synthetic Aperture Radar (SAR) image, a novel method based on kernel estimate, with the Markov context and Dempster-Shafer evidence theory is proposed. Initially, a nonparametric Probability Density Function (PDF) estimate method is introduced, to describe the scene of SAR images. And then under the Markov context, both the determinate PDF and the kernel estimate method are adopted respectively, to form a primary classification. Next, the primary classification results are fused using the evidence theory in an unsupervised way to get the scene classification. Finally, a regularization step is used, in which an iterated maximum selecting approach is introduced to control the fragments and modify the errors of the classification. Use of the kernel estimate and evidence theory can describe the complicated scenes with little prior knowledge and eliminate the ambiguities of the primary classification results. Experimental results on real SAR images illustrate a rather impressive performance.     

基于逆向工程的皮纹雕刻加工技术研究

介绍了皮革纹理的逆向工程技术，分析了纹理的数据采集、特征处理、CAD曲面重构等方法，并通过实例验证了其四轴雕刻加工的可行性．为皮纹的模具制造奠定了基础．     

基于Keystone变换的地面运动目标检测研究

合成孔径雷达 (SAR)在检测地面运动目标中所面临的难题之一是距离和速度的耦合导致了地面运动目标在SAR图像中模糊、错位、甚至消失。分析了Keystone变换的原理 ,提出了Keystone变换在一般正侧式SAR系统具体实现的方法与步骤 ,分析了Keystone方法对不同运动类型目标成像效果的修正作用。最后通过仿真证明了实现方法和分析结果的正确性。     

电子网板显影废液中铬的回收与利用研究

针对彩虹集团电子网板厂的含铬废水进行研究。先用氢氧化钠调节废液的pH值为7．5，使其沉淀抽滤。清液在酸性介质下，用蔗糖还原，使废液中的Cr^6 还原为Cr^3 ，将其配制成鞣革液，应用于皮革工业的鞣革，所鞣制的猪皮蓝湿革，各项技术指标已达到标准铬粉的同等水平，从而使含铬废水回收利用，在含铬废水处理上，从环境保护和应用方面开辟一条新的途径。     

对ay亚型优势人群中乙型肝炎自然感染程度的综合评判

本文改进了文[2]提出的综合评判数学模型,阐述了这个数学模型在乙型肝炎自然感染程度上的应用,并指出本方法优于文[1]的方法。