LEO's field emission scanning electron microscopes are all based an the “GEMINI” principle as shown in figure 1. In order to reduce aberrations and sensitivity to interfering stray-fields the electron optical column possesses a positively biased booster that shifts the energy of the primary electrons. The incident beam is focussed by a combination of a magnetic lens with an axial gap that avoids field leakage to the specimen and an electrostatic retarding lens formed by the beam booster together with the grounded pole piece cap. Shortly before the electrons hit the specimen they are decelerated down to the desired primary energy.

Ancient forests comprised an enormous biomass and typically flourished in lowland habitats that offered favorable conditions for fossllization, so it is not surprising that petrified wood is the most abundant terrestrial fossil. Petrifaction of wood by carbonates, sulfides, oxides, and phosphates is evidence that fossilization can occur under diverse geochemical conditions, but silicification is by far the most common process.

Theoretically, transmission electron microscopy (TEM) is compatible with three different types of phase plate: thin-film, electrostatic, and magnetic. However, designing functional phase plates has been an arduous process that has suffered from unavoidable technical obstacles such as phase-plate charging and difficulties associated with micro-fabrication of electrostatic and magnetic phase plates. This review discusses phase-contrast schemes that allow visualization of transparent objects with high contrast. Next it deals with recent studies on biological applications ranging from proteins and viruses to whole cells. Finally, future prospects for overcoming the problem of phase-plate charging and for designing the next generation of phase-plates to solve the problem of electron loss inherent in thin-film phase plates are discussed.

In his 2011 State of the Union address, President Barack Obama echoed the sentiments of this nation's leaders for the past twenty years when he stated, “Nations like China and India realized…they could compete in this new world. So they started educating their children earlier and longer, with greater emphasis on math and science. They're investing in research and new technologies…. Maintaining our leadership in research and technology is crucial to America's success. But if we want to win the future—if we want innovation to produce jobs in America and not overseas—then we also have to win the race to educate our kids.” The Bergen County Academies (BCA) in Hackensack, NJ, is attempting to do just that: invest in research and technology at the high school level in order to expose students to real world opportunities and applications they will experience in the future.

X-ray microfocus computer tomography (μ-CT) is a non-destructive experimental technique that reveals the 3D internal microstructure of the sample under study. The experimental set-up consists of an X-ray source, an X-ray detector, and set in between is a sample that is placed on a rotation stage. With this set-up multiple X-ray projection images can be obtained from the sample at different angles. In between the acquisition of two successive images, the sample is rotated over a small angle, typically between 0.2° and 1°. This set of projection images is then used as input for the reconstruction algorithm, which calculates a reconstruction of the internal microstructure of the sample with (sub-) micrometer sensitivity.

Feldspar is the name for a mineral group consisting of nearly 20 triclinic or monoclinic mineral species, of which only nine are well documented and widely distributed in the Earth's crust. Single members of the feldspar group belong to the so-called framework—or tectosilicates, where SiO4- and AlO4-tetrahedra share all their oxygen ions, resulting in an infinite three-dimensional network . Feldspar crystals include the major elements K, Na, Ca, Al, as well as Si and thus may be attributed to one of the following three endmembers: potassium-feldspar (K-feldspar) KAlSi3O8, albite NaAlSi3O8, or anorthite CaAl2Si2O8 (Table 1). Solid solutions occur between K-feldspar and albite, forming what is commonly known as alkali feldspar, and between albite and anorthite, forming plagioclase. The alkali feldspar group consists of orthoclase, microcline, sanidine, and anorthoclase, whereas the plagioclase group includes albite, oligoclase, andesine, labradorite, bytownite, and anorthite .

Bugscope is a free online microscopy outreach program that offers K–12 classrooms anywhere in the world the ability to remotely operate a high-resolution scanning electron microscope, collect images of insects and other similar arthropods, and chat simultaneously with a team of scientists. It was conceived and implemented in the late 1990s when K–12 schools were beginning to gain broadband Internet access, many as a result of the Telecommunications Act of 1996. One of several projects that took advantage of this opportunity to use the Internet to bring the laboratory into the classroom, Bugscope began as an NSF grant to purchase a field-emission scanning electron microscope and develop sophisticated client and server software to control it via a standard web browser. Inspired by the success of and lessons learned from the Chickscope remote magnetic resonance imaging project and from having successfully established remote web-based control of a transmission electron microscope, Clint Potter and Bridget Carragher created the Bugscope project with the goal of developing a remote microscopy educational outreach project that would be sustainable over the long term. This goal led to two significant design decisions. First, the software involved in setting up and running the live outreach sessions was purpose-built to ensure that only one staff member, if necessary, would be required at the instrument (as opposed to Chickscope, which required staff at the remote location as well as at the instrument). Second, students from a local high school would be employed as a renewable resource to help with pre-session sample preparation and to participate in live chat, answering questions from the remote classrooms. Although we now operate with permanent staff at the instrument, these efficiencies in the original concept/design have allowed Bugscope to operate continuously since March 1999, long after the original funding was exhausted.

Bone is an important material in many scientific disciplines because of its unique structure-property relationships, which are intrinsically dependent on its nanoscale components, bioapatite and collagen. As a living tissue, bone has evolved over hundreds of millions of years, and most vertebrates are now extinct. However, the vast majority of the relevant literature has engaged only modern bone tissues, neglecting the deep time perspective. Why?

SEM users are familiar with two forms of contrast in SEM images: topographic contrast and atomic number contrast. We can now add a third form of contrast. Contrast can arise due to the different orientation of grains in the sample. However, in normal operation this con trast is very weak, since in the SEM the beam includes a range of incident angles. This has the effect of averaging out diffraction contrast from the different orientations of the grains. This contrast is generally much stronger when the trast is very weak, since in the SEM the beam includes a range of incident angles. This has the effect of averaging out diffraction contrast from the different orientations of the grains. This contrast is generally much stronger when the incident beam is an ion beam rather than an electron beam — contrast between the grains is strong in ion-beam images but not in normal SEM images.

Energy-dispersive X-ray spectrometry (EDS) is an analytical technique used to determine elemental composition. It is a powerful, easy-to-use, non-destructive technique that can be employed for a wide variety of materials. In this technique the electron beam of the scanning electron microscope (SEM) impinges on the sample and excites atomic electrons causing the production of characteristic X rays. These characteristic X rays have energies specific to elements in the sample. The EDS detector collects these X rays as a signal and produces a spectrum. Samples also can be excited by X rays. Collimated and focused X rays from an X-ray source produce characteristic X rays that can be detected by the same EDS detector. When X rays are used as the source of excitation, the method is then called X-ray fluorescence (XRF) or micro-XRF.

Several color filters have been developed for astronomic use in order to improve image quality in visual observations and astronomic photography. Various positive effects, which can be achieved in astronomic practice, have already been described by several authors, manufacturers and distributors [2, 4, 5, 9, 10, 12]. Monochromatic narrow-band filters are widely used by astronomers. These filters are constructed as interference filters; they select small ranges within the spectrum of the visible light corresponding with characteristic radiation emitted by celestial nebula or the sun and its protuberances. This way, scattered terrestrial radiation caused by “light pollution” and non visible infrared or ultraviolet spectral components are blocked. Fundamental improvements of image quality will result from these filters when refractors or reflector telescopes are fitted with them.

It has become increasingly obvious that infrared microspectroscopy can be the analysis tool of choice when determining the chemical composition of biological and biomedical samples. Frequently, fluorescence illumination is required for sample characterization, which previously required the use of a separate optical microscope. There has also been a need in the semiconductor manufacturing industry for a single tool for visualizing particle contaminants on integrated wafers as well as the ability to chemically determine their nature. There is now a single microscope platform for conducting rapid Nomarski differential interference contrast and fluorescence illumination sample visualization as well as infrared analysis. This novel infrared microscope has applicability to many fields of investigation, including pharmacology, forensics, cell biology, histology, gemology, and geology.

There are relatively few technologies for measurement at the single-molecule scale. Fluorescent imaging, for example, can be used to directly visualize molecules and their interactions, but diffraction limitations and labeling requirements may push the system from its native state. Although recent advances in super-resolution imaging have been able to break this resolution barrier, important challenges remain. Atomic force microscopy (AFM) is capable of imaging molecules at high resolution and at high speed. However, AFM imaging is a surface technique, requiring sample preparation and some immobilization. Other technologies such as optical tweezers and magnetic tweezers are capable of molecular manipulation and spectroscopy to great effect but require a significant apparatus and have limited inherent analytical capabilities.