负像

The negative angle of refraction behavior associated with the negative index of refraction exhibited by DNG metamaterials is demonstrated.

并利用点源模拟出平面双负材料具有突破Rayleigh衍射极限使倏逝波成像的能力即：完美透镜现象。

That patient merit of the unworthy takes,With a bare bodkin? who would fardels bear,To grunt and sweat under a weary life,But that the dread of something after death

谁愿意负着这样的重担，再烦恼的生命的压迫下呻吟流汗，倘不是因为惧怕不可知的死后，惧怕那从来不曾有一个旅人回来过的神秘之国，是他迷惑了我们的意志，使我们宁愿忍受目前的磨折，不敢像我们所不知道的痛苦飞去？

The second lens group includes a 2nd-group 1st positive lens, a 2nd-group 1st compound lens formed by joining a 2nd-group 2nd positive lens having a convex surface on the image plane side and a 2nd-group 1st negative lens having a concave surface on the screen side, and a 2nd-group 3rd positive lens arranged in that order from the screen side toward the image plane side.

第二透镜组包括一个第2组第一正透镜，一个由在像平面侧具有凸面的第2组第二正透镜和一个在屏幕侧具有凹面的第2组第一负透镜结合的第2组第一组合透镜，和一个第2组第三正透镜，它们以从屏幕侧到像平面侧的顺序布置。

Each pixel on multispectral and hyperspectral imagery can also be regarded as one vector and the whole image is a convex cone formed by a number of nonnegative discrete vectors,so endmember selection is equivalent to search for the vertices of a convex cone.

遥感图像中的每个像元都可以看作一个多维向量，整幅影像看作由离散的非负向量构成的凸锥，通过寻找凸锥的角点来自动获取图像的端元。

If Q2 were negative, this might be representation of E2, pointing to negative charge, and if this one (Q3) were negative, then I would have here the contribution E3, and so on, and now we use the superposition principle as we did last time which Coulomb's law, that the net electric field at point p is a vector, is E1 influence of charge Q1, plus the vector E2, plus E3 and so on.

如果Q2是负的，这就是Q2的表示法，方向指向负电荷。如果这个是带负电，它将贡献电场E3，等等。现在我们使用叠加原理，就像我们上次在库伦定律中使用到的。

This paper presents a new scheme based on Nonnegative Matrix Factorization and simplex-based method to solve this problem.

本文提出一种新的基于非负矩阵因式分解(Nonnegative Matrix Factorization，NMF)算法和单形方法相结合的混合像元分解方法去解决上述问题。

The induced changes in log mesopic contrast sensitivity showed significant negative correlation with the changes in third-order (r =-0.490, P =.0013 without glare; r =-0.362, P =.0177 with glare; Spearman rank correlation coefficient) and fourth-order root mean square (r =-0.586, P =.0001 and r =-0.306, P =.0450, respectively).

中间视力对比敏感度log值的变化与三阶像差(r =-0.490， P =。0013 无眩光； r =-0.362， P =。0177 ，有眩光； Spearman 等级相关系数)和四阶像差(r =-0.586， P =。0001无眩光；； r =-0.306， P =。0450有眩光，)的均方根呈显著负相关。

In this dissertation, we first adopted many methods to determine the number of endmembers, then a method by combining the a prior knowledge of hyperspectral data into nonnegative matrix factorization was proposed to unmix hyperspectral images when there are no pure pixels existing in data.

在本文中，我们首先采用多种方法对超光谱图像端元个数的确定进行分析，然后将超光谱图像的先验知识加入到非负矩阵分解中，对纯像元不存在情况下的超光谱数据进行混合像元分解，实验结果表明本文中提出的方法是有效的和可行的。

Once delivered to the heart, injected cells are difficult to distinguish from target tissue by MR in vivo.To specifically imaging injected cells in MR, the recent investigation generally using superparamagnetic iron oxid to label MSCs, which should enable serial tracking and quantification of MSC transplantation noninvasively by MR.

由于MR成像无法区分移植细胞和靶组织细胞，为使移植细胞能在MR上特异性显示，目前广泛使用超顺磁性氧化铁(superparamagnetic iron oxid， SPIO)作为负性标记物标记移植细胞，进行MR体外和活体内的成像研究。

As a singlet curved lens is impossible to correct all the five primary aberrations regardless it is made of PIMs or NIMs, the primaxy-aberration-free lens systems composed of two thin lenses or two thick lenses based on the use of NIMs are intentionally presented.

由于只靠单块曲面透镜是无法同时消除全部五种初级像差的，因而我们接着研究了由负折射率介质构造的能同时消除全部五种初级单色像差的双薄透镜组合系统和双厚透镜组合系统。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。