مجله دانش آزمایشگاهی ایران
پیاپی 12 (زمستان 1394)

Advances in nanotechnology over the past decade have made scanning electron microscopy (SEM) an indispensable and powerful tool for analyzing and constructing new nanomaterials. Many efforts have been made to attain higher quality images and to facilitate the work done by the scanning electron microscope. One of the measures taken to change and correct is relevant to the source of electrons as known as the filament. The filament has various types which using each of them depends on the expected results. This article is an attempt to become more familiar with the different types of filament used in the scanning electron microscope and then comparison and also applications will be discussed.

Electron tomography is a well-established technique for three-dimensional structure. Almost amorphous specimens in life sciences can be determined by 3D tomography images. There's an urgent need for new approaches in tomography. In current study, applications, advantages and limitations of electron tomography in various specimens are discussed.

Piezoresponse force microscopy (PFM) detects the deformation of a piezoelectric material caused by an applied electric field from the tip of a scanning force microscope. PFM is able to measure deformations and also it can map topography and ferroelectric domains with a lateral resolution of a few nanometres. These two properties have made PFM the preferred technique for recording and investigating ferroelectric domain patterns. In this review we shall describe the basic principle of PFM for domain imaging, imaging modes, quantitative analysis of images, advanced PFM modes, applications and advantages and disadvantages of PFM.

Gas chromatography mass spectrometry (GC/MS) is an instrumental technique, comprising a gas chromatograph (GC) coupled to a mass spectrometer (MS), by which complex mixtures of chemicals may be separated, identified and quantified. This makes it ideal for the analysis of the hundreds of relatively low molecular weight compounds found in environmental materials. In order for a compound to be analyzed by GC/MS it must be sufficiently volatile and thermally stable. In this article, this system was reviewed.