【正文】 tions. In these two papers the sample is assumed to be purely absorptive, so that in principle Streibl’s technique would yield goodquality results. However, in Streibl’s method, the 3D system is angularly bandlimited by the aperture of the objective. This implies that only a part of the object’s 3D frequency representation can be obtained. The papers by Kawataet al. (1987) and Nakamura et al . (1987) are an attempt to recover some of the missing information by using appropriate constraints for reconstruction, thus improving image quality. In the present paper, and in the case of a purely absorptive sample, we obtain the same part of the frequency representation that is obtained by Streibl in the limit case of incoherent illumination. The image that we finally obtain for absorptive samples is similar to Streibl’s deconvolved images. However, we do not attempt to constrain reconstruction and partially recover the missing part of the frequency representation, as is done in the papers by Kawata et al.(1987) and Nakamura et al. (1987). 3D imaging of phase structures was successfully realized by Noda et al . (1990, 1992). In these two papers, the authors simultaneously use phasecontrast and successive illumination by plane waves varying in direction. Their method can be regarded as a holographic technique using the phaseshifted illumination beam as a reference beam. It yields good results but it is limited to phase structures. Another experimental method is the use of a series of illuminating waves of varying direction, bined with a detection method based on inline holography (Devaney amp。 Maleki et al. , 1992). In such methods, the absence of phase shifting is partly pensated by appropriate phase retrieval algorithms. These methods have been the subject of extensive research and improvements, and have been applied to translationally invariant objects such as fibres (Wedberg amp。 Wedberg et al. , 1995). Although phaseshifting holography seems a straightforward method to record both the phase and amplitude of a scattered wave, its practical implementation has faced difficulties that are mostly related to the fact that only phase differences can be measured, and that phase relations between distinct waves cannot be accurately controlled. In this paper, we use a measurementorientated approach to diffraction tomography, taking into account not only the scattered wave and the illuminating wave, but also the reference wave and the phase relations between these three waves. This is facilitated by an appropriate frequencyspace analysis. The mathematical basis for this analysis is first established in the vector case, yielding a vector equation of diffraction tomography in a very simple form. This frequencyspace analysis uses a frequency representation of waves, which is made possible by considering linear binations of homogeneous plane waves rather than outgoing waves, which do not have a frequency representation. The measurementorientated approach of diffraction tomography is then presented within the framework of a concrete prototype detecting the scattered wave in a Fourier plane. A simplified scalar approximation of the vector equations is used to describe this prototype, still taking advantage of the frequency representation of waves. An appropriate equation is obtained for reconstruction, which in particular pensates for the random phase shifts that occur between the illuminating waves and the reference wave. 羅列很多方法后，總結(jié)了本文的實(shí)驗(yàn)方法。前人的方法羅列出來(lái)，各自缺點(diǎn)是什么，列出了一條實(shí)驗(yàn)線索鏈，下一種方法是上一種方法缺點(diǎn)的補(bǔ)充，再過(guò)渡到本文的研究中，是基于前者實(shí)驗(yàn)的擴(kuò)展。然后，指出研究中存在的一些問(wèn)題，回顧以往前人的一些研究（一般是按時(shí)間的順序，研究成果上也有遞進(jìn)的意思，即一個(gè)指標(biāo)解決了，但是還存在尚未解決的問(wèn)題，再接著給出一個(gè)例子，解決了上面的問(wèn)題，但還有不足，最后承轉(zhuǎn)到本文的研究中），用到一些實(shí)驗(yàn)成果對(duì)比，哪些方面還存在不完善的地方，哪些地方還存在分歧。在一些前言中，最后還會(huì)分別羅列說(shuō)明文章主體研究的各個(gè)部分是什么，或者本文研究成果的優(yōu)點(diǎn)各是什么。一般由下面三個(gè)部分組成： ① 歸納總結(jié)本論文主要研究的內(nèi)容和結(jié)論，意義 ② 本論文主要?jiǎng)?chuàng)新點(diǎn)（是基于前人結(jié)論的擴(kuò)展延伸，還是另辟蹊徑，有了新的創(chuàng)新結(jié)果） ③ 研究存在的問(wèn)題、不足或進(jìn)一步工作的設(shè)想 還需要注意的是要在用詞和所使用句型上避免與引言、討論中相關(guān)內(nèi)容的雷同。養(yǎng)成總結(jié)收集一些句式的習(xí)慣，這樣的優(yōu)點(diǎn)在于：① 有利于避免不必要的重復(fù) ② 有利于比較地道、規(guī)范的英語(yǔ)表達(dá) ③ 有利于寫(xiě)作中的多樣化表達(dá) 總結(jié)的一些句式供同學(xué)們參考： 舉例說(shuō)明，羅列方法的一些表達(dá)方式：① For example, highly sensitive sensors, in which the critical resonance condition of the surface plasmon is used, have been developed to measure refractive indices.② The advantages of evanescentwave holography with SPR are as follows:（羅列出來(lái)）⑴ The zerothorder diffraction of the illumination light does not appear in the reconstruction field.③ Such a limitation is dictated by the dispersion characteristic, Kz = ω2μεKx,y2, of the medium surrounding the sample, which causes the high spatialfrequency ponents (. large Kx,y) from the sample to decay exponentially with distances and ultimately bee lost in the far field.④ The most important aspect of the present paper is that we successfully use phaseshifting holography with successive illumination beams of different directions, as was originally suggested by Wolf (1969).⑤ The advantage of using phaseshifting holography, as in the present paper, is that it allows the direct acquisition of the scattered wave.⑥ There are（there be的句型引出4） several challenges in extending such models into the domain of NEMS. First, sub wavelength NEMS sizes require the accurate solution of the electromagnetic （EM） field equations in the vicinity of the device. Second, due to the layered nature of most NEMS, the EM field travels in several different media, thus necessitating a careful consideration of material properties. Third, incorporation of the solutions in the device near field into a realistic model with a farfield detector is putationally intensive. ⑦ Several key elements ought to be considered（引出4）: （a） the effective NEMS interaction with the EM field, （b） the propagation of the EM field to the detector, and （c） the detection of the optical signal via the photo detector circuitry.⑧ At the center of the approach presented here is a numerical analysis of the EM field in the vicinity of the NEMS. 意思遞進(jìn)的一些表達(dá)方式：① Another more recent example is the demonstration of an antennab