1,721,153 research outputs found
Lithography
No full textLithography became an essential tool for materials research during the post-World War II computing revolution. Increasing computing power required shrinking circuits and packing transistors more tightly together. Lithography made it possible to write small, precise circuits on a semiconducting surface, setting the stage for modern computing and fueling Moore’s Law - the observation that transistor density on chips has tended to double every eighteen months. But lithography was by no means a postwar development. It dates to the late-eighteenth century and is notable as a technique borrowed for materials research from the storied and ostensibly distant craft practices of ink-based printing. What ties these disparate applications together - aside from their name - is their close relationship to the commercial incentives of the times in which they developed….</p
Introduction:Tools in Materials Research
Get PDFThe science of materials has contributed to changes in our civilization as pervasive as they are profound. The ways we travel, communicate, wage war, build buildings, dress, heal, play sports, read, listen to music, use energy, and care for the young, the old, and the vulnerable have all been shaped and reshaped by our knowledge and mastery of metals, semiconductors, organic and biocompatible materials, gels, plastics, polymers, plasmas, and other substances. But our large-scale historical understanding of materials research is still surprisingly flimsy. We might say of materials research, as common as it is, what Clifford Geertz said of common sense: “it lies so artlessly before our eyes it is almost impossible to see”….</p
The Diverse Ecology of Electronic Materials
Get PDFSilicon has been the dominant material in microelectronics for a half century. Other materials, however, have subsidiary roles in microelectronics manufacturing. A few materials have even been promoted as replacements for silicon. Yet because of silicon’s dominance, none of these alternatives has gone from bench to brand; nor could any of them progress from brand to bench. For these reasons, historians have paid little attention to silicon and almost none to other microelectronics materials. I show, however, that we can better understand how the organization of the semiconductor (silicon) industry has changed over time by examining alternative microelectronic materials. I do so by presenting two case studies: one of a superconducting computing program at IBM, the most likely candidate to overthrow silicon in the ‘70s; the other of carbon fullerenes, the most likely candidates to overthrow silicon today
Vacuum Chambers, Pumps, Gauges, and Systems
No full textWe often think of scientists as working directly with their experimental materials. The image of the chemist staring upward into the beaker is, after all, one of the most pervasive icons of the scientist. Yet in many fields, experimental materials (and the conditions necessary for their existence) are a threat to scientists, and/or scientists (and the conditions necessary for their existence) are a threat to experimental materials. In such cases, scientists must essentially build remote laboratories - micro-environments in which they can only interact with their materials at a distance. Vacuum is one of the oldest and most important such micro-environments in the history of laboratory science.</p
Simple heating
No full textIn the twentieth century, researchers learned to expose materials to tremendous extremes of temperature using lasers, highly specialized ovens, and other techniques. Yet materials researchers still required more modest means of raising temperature: Bunsen burners, hot plates, blowtorches, and so on. These techniques and their precursors go back centuries if not millennia. Indeed, controlled production and application of heat was one of the technologies that enabled the emergence of complex societies, if not our species itself. The editors have therefore chosen to place discussion of forms of heating with ancient roots in this section of the volume and label them “Simple Heating” in contrast to the techniques discussed in Part 3 under “Complex Heating.” This is, however, something of a misnomer; some of these ancient techniques are not very simple, and all of them continue to evolve
Probe and Other Microscopies
No full textThe history of twentieth-century microscopy is often told as a transition from imaging with light (focused using glass lenses) to imaging with electrons (focused using magnetic lenses). In that story, electrons are simply particle-waves, which act like photons but have a much higher frequency and therefore better theoretical resolution (see chapters on transmission electron microscopy, scanning electron microscopy, and lithography). Even in the 1930s, though, researchers saw that electrons could image surfaces in ways not analogous to light. Such techniques developed and diffused slowly, despite achievements such as the first images of individual atoms. In the 1980s, though, one variant - the scanning tunneling microscope - caught on and led to the invention of the atomic force microscope and its relatives. These “probe” microscopes are now as common as electron microscopes. Their success has catalyzed the union of materials research and the life sciences that accelerated at the turn of the twentieth century.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
