bluuebunny/crossref_metadata_2025_split huggingface dataset:
Poled Glasses
Authors: Margulis W. , Garcia F.C. , Hering E.N. , Guedes Valente L.C. , Lesche B. , Laurell F. , Carvalho I.C.S. 
Published: August 2016

Glass is the most important material in optics, with uses in optical fibers, lenses, mirror substrates, and prisms. The silicate family, the prime material in this article, is well-suited for passive optical functions such as light guidance in a fiber. Because of its many desirable properties, one is tempted to use glass in active functions as well—such as in amplification and modulation of light. As early as the beginning of the 1960s, glasses doped with rare-earth ions were used as gain media for lasers. Nd:glass lasers and Erdoped fiber amplifiers are two examples of the success of the use of doped glass to perform an active optical function. The modulation and switching of light proved to be a more difficult task to perform with glass systems. Glass has very low optical nonlinearity, and the application of an electric field does little to the optical wave traveling in the material.In 1991 Myers, Mukherjee, and Brueck submitted a polymer film on a silica substrate to a poling process, which consists of the application of high voltages at a temperature of ~300°C. After cooling to room temperature with the voltage still applied, the poled sample was illuminated with a strong infrared (ir) laser beam. As expected they found that material frequency-doubled the incoming radiation and some green light could be measured at the output. When a test was carried out to discard any contribution from the substrate to the frequency-doubled light, they discovered that it was the silica glass that was generating the green light and that they had induced a strong optical nonlinearity in silica by thermal poling. Since then poling of glasses in the context of nonlinear optics has been the subject of many publications, including the report that ultraviolet (uv) radiation can advantageously replace thermal excitation.
Scanning Electron-Acoustic Microscopy: Do You Know Its Capabilities?
Authors: Urchulutegui M. 
Published: August 2016

Characterization of materials usually requires microscopy techniques. Some of the most useful are based on a scanning microscope and involve scanning the sample surface with a focused beam (e.g., photons, electrons, ions, etc.). For example, photoacoustic microscopy uses a laser beam, acoustic microscopy uses an ultrasound beam, and scanning electron microscopy uses an electron beam. The interaction between the material and the beam produces a signal that can be used to generate a two-dimensional image.In scanning photoacoustic microscopy (SPAM), an intensity-modulated light beam is used to produce oscillations in the surface temperature of the sample. These oscillations induce changes in the pressure of a fluid in the photoacoustic cell as a consequence of the periodic heat conduction from the surface to the cell fluid. Subsequently many material-characterization methods have employed the same philosophy as SPAM, using a modulated beam as an excitation probe. The breadth of such techniques is due to the large number of possible excitation sources and signal detectors that have been proposed to probe the specimen response. In particular, scanning electron-acoustic microscopy (SEAM), also referred to as thermal wave microscopy, is a technique based on the utilization of a scanning electron microscope developed in 1980 and applied in recent years to material characterization. It can be considered an additional mode of scanning electron microscopy (SEM), which uses the generation of acoustic waves in the sample. Most reviews have concentrated on the application of SEAM to metals and semiconductors. However many other possibilities exist.
The Importance of New Processing Techniques in Tissue Engineering
Authors: Lu Lichun , Mikos Antonios G. 
Published: August 2016

Tissue engineering offers the possibility to create completely natural tissue and replace failing or malfunctioning organs. In many cases, biocompatible, biodegradable polymers are utilized to either induce surrounding tissue and cell ingrowth or to serve as a temporary scaffold for transplanted cells to attach, grow, and maintain differentiated functions. Various processing techniques have therefore been developed to fabricate polymers with specific properties to meet the needs of a particular organ.Polymer scaffolds must possess unique physical and chemical properties for specific applications and must satisfy some basic requirements for tissue engineering. These scaffolds may be implanted without cells, and the regeneration depends on ingrowth of surrounding tissue to such materials—a process known as tissue induction. Alternatively cells may be seeded into a porous polymer. The cell-polymer construct is then transplanted. In either case, one essential criterion for the scaffold is biocompatibility—that is, the polymer scaffolds and their degradation products should not invoke an adverse immune response or toxicity.Because of the problems associated with long-term implants, such as infection, fibrous tissue formation, and the possible need for retrieval, the role of polymer scaffolds should only be a temporary one. The degradation rate is optimized to allow transplanted cells to proliferate and secrete their own extracellular matrix (ECM) while polymer scaffolds can vanish when necessary to leave enough space for new tissue growth. Biodegradability of a polymer is determined by its composition, molecular weight (MW), MW distribution, degree of crystallinity, and environmental conditions such as temperature and pH. Mechanical loading of the scaffold may affect its degradation.
Material Matters
Authors: McTague John P. 
Published: August 2016

The following is an edited transcript of the plenary lecture presented by John P. McTague at the 1996 MRS Fall Meeting on December 2,1996 in Boston.Long before 1993, the journey from New York City to San Francisco, across the continent, and from New York City to London, across the sea, will be made between the sunrise and sunset of a summer day. The railway and the steamship will be as obsolete as the stagecoach. And it will be as common for the citizen to call for his dirigible balloon as it now is for his buggy or his boots. Electricity will be the motive power, and aluminium or some lighter metal will be the material of the aerial cars, which will navigate the abyss of the sky.John J. Ingalls“Remarkable Changes in Everyday Life”(1893)
Material Matters
Authors: Diol Sabrina J. 
Published: August 2016

Through my interdisciplinary graduate work, I have attended conferences organized by various professional societies such as the Materials Research Society (MRS), American Physical Society (APS), Optical Society of America (OSA), and American Chemical Society (ACS). I have also participated in some of their employment workshops and have searched their websites for employment resources. This article elaborates on information and services that professional societies and organizations can provide to ease employment search for their student membership.Career Workshops. These workshops provide excellent guidance, especially for students initiating their employment search. Obviously, the best ones are conducted by people who recruit PhD graduates. I attended an employment workshop organized by the American Institute of Physics (AIP) during the 1995 MRS Fall Meeting. An extremely dynamic hightechnology industrial recruiter conducted the workshop. The mock interviews, mininetworking groups, and resume and cover letter critique involved audience participation and were highly effective. I strongly recommend such a workshop. On the other hand, I have also been frustrated with workshops in which speakers did not have a technical PhD background since I often found their suggestions unsuitable.Employment Database. A website with current job postings mainly for PhD graduates is extremely useful. The National Academy of Science (http://www2.nas.edu) is among the few sources for this. The critical issue in this case is to have a well-maintained site with frequent updates and a search engine. Another alternative, which we have been using at the University of Rochester, is to circulate job postings via electronic mail. Again, timeliness is the key issue.
Magneto-optic Recording Materials
Authors: Suzuki Takao 
Published: August 2016

With significant developments in laser and semiconductor industries, optical-storage technology has successfully emerged into the consumer marketplace and more recently into the computer-based data-storage marketplace as well. For computer-based data storage and other purposes, the first generation of the International Standards Organization (ISO) standard 5-1/4-in. magneto-optic (MO) drive (325 Mbytes × 2/double-sided) was introduced in 1988 and the 3.5-in. drive (128 Mbytes) in 1991. Since then progress has been remarkable in capacity and data-transfer rate as well as cost/performance ratio, and the so-called 2X (650 Mbytes × 2 per 5-in. double-sided disk) and 3X (1 Gbyte × 2 per 5-in. double-sided disk) drives are now in the marketplace. Also a remarkable product called the MiniDisc (2.5 in.), the first recordable optical system for both the consumer and the data market, utilizes data compression and direct overwrite schemes.The solution for increasing the capacity is by no means simple since the new technology must accommodate many factors. One of the key factors is backward compatibility. This feature is important to removable media because the customer expects new products to be compatible with their previous investments in data stored on older generation media. Another key factor is cost. The sales price ($/Mbyte) must be significantly lower than prior generations of optical-storage products and alternative storage systems (e.g., removable hard disks).To increase the capacity in optical-storage media, several solutions are possible: short-wavelength lasers, magnetically induced super resolution (MSR), pulse width modulation (PWM), volumetric recording, land/groove recording with crosstalk cancellation, partial-response channels, banding of data, and higher numerical aperture objective lenses.
Erasable Phase-Change Optical Materials
Authors: Yamada Noboru 
Published: August 2016

Almost all stones on a lane will become glassy if they are melted and quenched. They will become transparent and quite different in appearance from before vitrification. This visible change constitutes the recording of information. We might refer to the stone as “1 bit.” If the vitrified stone is subsequently kept at a high temperature under its melting point, it will lose its transparency and turn back to the appearance it had before melting and quenching. Thus the “1 bit” is erased. This is the simple mechanism of an erasable phase-change optical memory. In practical systems, a laser beam focused into a diffraction-limited spot is used for recording. This enables the spatial size of the “1 bit” to be very small (of submicron order) so that the recording density is very high.Figure 1 shows a transmission-electron-microscope (TEM) photograph of an actual optical disk. The elliptical smooth areas are recording marks in the amorphous state that were formed by high-power and short-duration laser irradiation. The shortest mark length is about 0.5 μm. The area surrounding the amorphous marks is in the crystalline state and consists of small grains. The two states differ from each other in optical properties such as refractive indices and optical absorption coefficients. Accordingly when the bits are illuminated with low-intensity laser light, the reflected light from the amorphous and crystalline regions is different and may be detected as information signals.The amorphous marks are erased by heating above the glass-transition temperature by laser irradiation, but with lower power than is used in the case of recording.
Multiple Scattering Probes of Disordered Materials
Authors: Weitz D.A. , Pine D.J. 
Published: August 2016

A large class of materials of great technological importance and scientific interest are highly disordered on length scales comparable to, or larger than, the wavelength of light. As a consequence of this disorder, these materials are often composed of a large number of regions with different indices of refraction, separated by interfaces that are abrupt on the scale of the wavelength of light. Each of these interfaces refracts or scatters light, making these materials quite opaque optically. Even in the absence of absorption, the strong scattering precludes the direct transmission of light rays through the material. This greatly complicates the study of these materials.Examples of these disordered materials abound. Many are complex fluids; colloidal suspensions and other dispersions such as foams and emulsions often consist of particles or droplets whose diameters are comparable to the wavelength of light. Unless they are very dilute, these dispersions are typically highly opaque. Other materials consist of solid grains of similar sizes without the surrounding fluid. For example, most ceramics are composed of oxide grains sintered together; the voids between the grains lead to the large number of interfaces, and hence to the strong scattering and opaque appearance commonly associated with these materials. Similarly, many porous materials also possess a high density of voids that scatter light; filters, oxide catalyst supports, and even rocks are all optically opaque because of the strong scattering. Sand and other unconsolidated granular materials are also opaque in part because of the large number of interfaces that scatter light.
Materials Science in the Electron Microscope
Authors: Ross Frances M. 
Published: August 2016

This issue of the MRS Bulletin aims to highlight the innovative and exciting materials science research now being done using in situ electron microscopy. Techniques which combine real-time image acquisition with high spatial resolution have contributed to our understanding of a remarkably diverse range of physical phenomena. The articles in this issue present recent advances in materials science which have been made using the techniques of transmission electron microscopy (TEM), including holography, scanning electron microscopy (SEM), low-energy electron microscopy (LEEM), and high-voltage electron microscopy (HVEM).The idea of carrying out dynamic experiments involving real-time observation of microscopic phenomena has always had an attraction for materials scientists. Ever since the first static images were obtained in the electron microscope, materials scientists have been interested in observing processes in real time: we feel that we obtain a true understanding of a microscopic phenomenon if we can actually watch it taking place. The idea behind “materials science in the electron microscope” is therefore to use the electron microscope—with its unique ability to image subtle changes in a material at or near the atomic level—as a laboratory in which a remarkable variety of experiments can be carried out. In this issue you will read about dynamic experiments in areas such as phase transformations, thin-film growth, and electromigration, which make use of innovative designs for the specimen, the specimen holder, or the microscope itself. These articles speak for themselves in demonstrating the power of real-time analysis in the quantitative exploration of reaction mechanisms.The first transmission electron microscopes operated at low accelerating voltages, up to about 100 kV. This placed a severe limitation on the thickness of foils that could be examined: Heavy elements, for example, had to be made into foils thinner than 0.1 μm. It was felt that any phenomenon whose “mean free path” was comparable to the foil thickness would be significantly affected by the foil surfaces, and therefore would be unsuitable for study in situ. However, technology quickly generated ever higher accelerating voltages, culminating in the giant 3 MeV electron microscopes. At these voltages, electrons can penetrate materials as thick as 6–9 μm for light elements such as Si and Al, and 1 μm for very heavy ones such as Au and U.
Low-Energy Electron Microscopy
Authors: Tromp Ruud M. 
Published: August 2016

For surface science, the 1980s were the decade in which the microscopes arrived. The scanning tunneling microscope (STM) was invented in 1982. Ultrahigh vacuum transmission electron microscopy (UHVTEM) played a key role in resolving the structure of the elusive Si(111)-7 × 7 surface. Scanning electron microscopy (SEM) as well as reflection electron microscopy (REM) were applied to the study of growth and islanding. And low-energy electron microscopy (LEEM), invented some 20 years earlier, made its appearance with the work of Telieps and Bauer.LEEM and TEM have many things in common. Unlike STM and SEM, they are direct imaging techniques, using magnifying lenses. Both use an aperture to select a particular diffracted beam, which determines the nature of the contrast. If the direct beam is selected (no parallel momentum transfer), a bright field image is formed, and contrast arises primarily from differences in the scattering factor. A dark field image is formed with any other beam in the diffraction pattern, allowing contrast due to differences in symmetry. In LEEM, phase contrast is the third important mechanism by which surface and interface features such as atomic steps and dislocations may be imaged. One major difference between TEM and LEEM is the electron energy: 100 keV and above in TEM, 100 eV and below in LEEM. In LEEM, the imaging electrons are reflected from the sample surface, unlike TEM where the electrons zip right through the sample, encountering top surface, bulk, and bottom surface. STM and TEM are capable of ~2 Å resolution, while LEEM and SEM can observe surface features (including atomic steps) with -100 Å resolution.
Defects in Intermetallic Compounds: How Do They Differ From Those in Ordinary Metals?
Authors: Sun Y.Q. 
Published: August 2016

Just as in ordinary metals, defects in intermetallic compounds fall into three basic categories: point defects (vacancies, substitutional and interstitial atoms), line defects (dislocations), and planar defects (stacking faults, interfaces, grain boundaries). Also like ordinary metals, many important physical and chemical properties of intermetallic compounds are governed by the presence of these defects and the effects on them from temperature, composition, chemical environment, elastic stress state, and so on.What ultimately distinguishes an intermetallic compound from ordinary metals is its superlattice crystal structure. A two-dimensional analogue of the actual three-dimensional superlattice structure is shown in Figure 1a where the superlattice (unit cell marked by full lines) is made up of two identical sublat-tices (unit cells marked by dotted lines). A property of the sublattice is that it is exclusively occupied by one atom species, and accordingly sublattices are named after the atoms that occupy them, for example, the A and B sublattices in Figure 1a. In three dimensions, a super-lattice may consist of several sublattices. For example, the L12 superlattice of Ni3Al consists of four interpenetrating cubic sublattices, one occupied by Al atoms (Al sublattice), the other three by Ni atoms (Ni sublattices). When the sub-lattices are occupied exclusively by their designated atoms, the crystal is said to be fully ordered. The crystal will be partially ordered if a certain fraction of the sublattice sites is taken up by atoms that would otherwise sit at other sublattices; this fraction is used to describe the degree of long-range order.
Modeling the Processing of Aluminum Alloys
Authors: Shercliff H.R. , Myhr O.R. , Tjøtta S. 
Published: August 2016

The production and use of aluminum alloys involves a wide range of processing and fabrication methods. For a number of reasons discussed in this article, process modeling has an increasingly important role in all areas of production. This article reviews some process modeling activities in aluminum processing. The aims of the review are to (1) describe the current state of research in two major processing areas, (2) establish the principal motivations in the aluminum industry for undertaking process modeling, and (3) to identify generic research issues most in need of attention. This review is not intended to be exhaustive, but considers only selected processes, based on work in Norwegian laboratories with which the authors are most familiar. There is considerable parallel modeling activity worldwide in industry and academia which will not be discussed here. The case studies selected are sufficient, however, to illustrate all the main points of the review.A recent review of materials process modeling identifies a number of recurring themes which indicate the commercial reasons why process modeling is undertaken in various industries. They may be summarized as modeling to (1) develop new or scaled-up processes, (2) reduce the number of trials, (3) optimize an existing process, and (4) improve quality by reducing product variability.So the overriding concerns in industry are improving productivity and quality, and reducing costs. Modeling is also important from the point of view of model based real-time control of processes, but developments in this area are at present limited to relatively slow processing operations. Models are also important tools for both industry and academia to improve scientific understanding of materials processing. Within a company, modeling serves as a means to assemble know-how about the company's processes, raising the level of training of the workforce and making it possible for people to learn a process quickly.
Up Close: New Jersey Advanced Technology Center for Surface-Engineered Materials: An Experiment in Research Management
Authors: Smith D.A. 
Published: August 2016

The Advanced Technology Center for Surface Engineered Materials (ATC-SEM) is a bold experiment in research management. Scientists from its five member institutions work independently within a central framework for overall planning and for the allocation of resources. Access to areas of expertise beyond the compass of the individual institutions more than offsets the logistical problems inherent in the distributed nature of the organization.ATC-SEM had its origins in 1988 as one of a number of Advanced Technology Centers established by a grant from the New Jersey Commission on Science and Technology after approval of the Jobs, Education, and Competitiveness Bond Act. All the ATCs are dedicated to improving the competitiveness of New Jersey's industry through the application of technology.The ATM-SEM is administered through Associated Institutions for Material Sciences (AIMS) which has six member institutions, five of which are universities. AIMS also administers other multicampus programs in New Jersey, including the New Jersey NASA space grant consortium and a SEMATECH Center of Excellence. The hallmark of each program is a collaborative effort which transcends the capabilities of any of the individual campuses. The consortium member institutions span the private, public, and industrial sectors and comprise the New Jersey Institute of Technology, Princeton University, Rutgers (the State University of New Jersey), Stevens Institute of Technology, the University of Medicine and Dentistry of New Jersey, and David Sarnoff Research Center (an independent contract research center).