Academic literature on the topic 'Silicon substarte'
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Journal articles on the topic "Silicon substarte"
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Greene, William B., Lyle G. Walsh, Richard M. Silver, Joann Allen, and John C. Maize. "Silicone gel in biological systems." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 1 (August 1992): 650–51. http://dx.doi.org/10.1017/s0424820100123659.
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Electron probe microanalysis of biopsies from two patients who had received silicone gel breast implants has revealed silicon (Si) in macrophages in an arthritic finger joint synovium (Fig. 1) and in a sclerodermatous skin lesion as well as in the fibrous capsule surrounding the implants in both patients (Fig. 2). The silastic envelope has been reported to be semipermeable with substances passing freely into and out of the implant. The polymer usually contains silica filler with a particle size of 30μm to impart added firmness, however, these sharp pointed crystals have not been fully characterized by Electron Microscopy. Silicone has been thought to be relatively inert, eliciting little or no tissue reaction. The substance has been injected or surgically placed into the human body as liquid, joints or in the form of breast augmentation prostheses. Recent reports have indicated that there is more than sufficient reason to change our thinking regarding this chemical and it's significance in biological reactions. There are 100,000 patients who undergo breast augmentation each year in the United States alone with over one million reported silicone implants. One clinical group reported that 4.4% of all new scleroderma patients had silicone breast implants. The patients reported in the study had implants from 2 to 21 years duration. The latency period may mean that scleroderma will increase parallel to the increase in breast augmentation over the last decade.
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Li, Jiao, and Jianguo Huang. "A nanofibrous polypyrrole/silicon composite derived from cellulose substance as the anode material for lithium-ion batteries." Chemical Communications 51, no. 78 (2015): 14590–93. http://dx.doi.org/10.1039/c5cc05300e.
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Jia, Dongling, and Jianguo Huang. "A bio-inspired nanofibrous silicon/carbon composite as an anode material for lithium-ion batteries." New Journal of Chemistry 41, no. 12 (2017): 4887–900. http://dx.doi.org/10.1039/c7nj00032d.
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Cao, Dao Tran, Cao Tuan Anh, and Luong Truc Quynh Ngan. "Origin of Mosaic Structure Obtained During the Production of Porous Silicon with Electrochemical Etching." Advanced Science, Engineering and Medicine 11, no. 12 (December 1, 2019): 1218–24. http://dx.doi.org/10.1166/asem.2019.2432.
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So far, while producing porous silicon (PSi) with anodic etching of silicon in an aqueous solution of hydrofluoric acid, many researchers (including us) have obtained the crack-into-pieces (or mosaic) structure. Most of the authors believed that the cause of this structure is the collapse and the cracking of the porous, especially highly porous, silicon layer which took place during the drying of PSi after fabrication. However, our study showed that the mosaic structure was formed right during the course of silicon anodization at high anodic current density. Furthermore, our study also showed that at high anodic current density the real silicon etching has been replaced by the growth of a silicon oxide layer. This is a layer of another substance that grows on silicon, so when the layer is too thick (which is obtained when the anodic current density is too high and/or the anodization time is too long) it will crack, creating mosaic pieces. When the silicon oxide layer is cracked, the locations around the cracks will be etched more violently than elsewhere, creating trenches. Thus, the mosaic structure with mosaic pieces emerged between the trenches has formed.
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Zhang, Yanhua, and Jianguo Huang. "Hierarchical nanofibrous silicon as replica of natural cellulose substance." Journal of Materials Chemistry 21, no. 20 (2011): 7161. http://dx.doi.org/10.1039/c1jm10282f.
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Yu, Xiao Hua, En He, Yan Qing Hou, and Gang Xie. "Thermodynamic Study on SiHCl3 Hydrogen Reduction System in Siemens Process." Advanced Materials Research 343-344 (September 2011): 156–59. http://dx.doi.org/10.4028/www.scientific.net/amr.343-344.156.
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The complex chemical reactions in the Si-Cl-H system with relation to modified Siemens process have been studied in this paper based on the thermodynamic data of related substance. The influence of the temperature, pressure and initial feed ratio (nSi / nSiHCl3) on the silicon yield have been studied. Furthermore, the diagram of Kinetic constant k as a function of temperature for the rate controlled reaction has also been fitted in the SiHCl3 hydrogen system. Finally 1425K, 1.5atm and the initial feed ratio of 15 is the best conditions. Under these conditions, the silicon yield is 34.815%.
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Bondarev, A. V., E. T. Zhilyakova, N. B. Demina, and V. Y. Novikov. "Study of Morphology of Sorption Substances." Drug development & registration 8, no. 2 (May 30, 2019): 33–37. http://dx.doi.org/10.33380/2305-2066-2019-8-2-33-37.
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Introduction. Substances with sorption properties can be used to create transport drug systems, in which the main mechanism of binding, transport and release of the drug molecule is sorption. The sorbent in this case acts as a carrier of the drug molecule, followed by its delivery to the destination by desorption. One of the ways to study the processes of sorption-desorption in transport drug systems is the study of the morphology of the sorption substance. Therefore, the morphological analysis of sorption substances is important, including the size, shape, and spatial organization of their structural elements.Aim. The study of the morphology of sorption substances.Materials and methods. The materials of the study are active coal, silicon dioxide, povidone, dioctahedral smectite, kaolin and montmorillonite clay. The methods is scanning electron microscopy.Results and discussion. The scanning electron microscopy of objects was carried out using segmentation of elements as subsystems, inside of which the morphological description does not penetrate. It was established that for coal of active and silicon dioxide, the segmentation of elements is represented by three levels of organization; for povidone, smectite, kaolin and montmorillonite clay, the segmentation of elements is represented by two levels of organization. The morphology of the objects was investigated. It is established that the studied substances are microstructural objects. Porosity in samples of active coal, smectite dioctahedral, kaolin, montmorillonite clay was determined. In samples of silicon dioxide and povidone porosity is absent.Conclusion. Morphological analysis of sorption substances allowed us to develop classification of the possible interaction of the carrier substance with the drug molecule in the transport drug system. The materials under study are divided into two groups according to porous characteristics: group 1 – porous substances – sorption interaction in pores (active coal), sorption interaction in pores and by ion exchange (smectite, montmorillonite clay), sorption in secondary pores and through oxygen and hydroxyl centers (kaolin); group 2 – non-porous substances – sorption on oxygen centers (silicon dioxide), sorption by means of complex formation (povidone). The prospect of further research is the modeling of porosity and sorption interaction of the carrier substance with the drug molecule in the drug transport system.
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HÄCKEL, S., J. DONEIT, A. PINKOWSKI, and W. J. LORENZ. "DIODE CHARACTERISTICS OF YBa2Cu3O7/n- TYPE SILICON CONTACTS." Modern Physics Letters B 02, no. 11n12 (December 1988): 1303–8. http://dx.doi.org/10.1142/s0217984988001284.
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The temperature dependences of diode characteristics were measured on high-T c -superconducting YBa 2 Cu 3 O 7 (polycrystalline)/n-type silicon (monocrystalline) contacts using a common two-pole-technique at low frequencies. The non-superconducting p-type semiconductor YBa 2 Cu 3 O 6.5 (polycrystalline) served as a reference substance. The temperature coefficients of the diffusion voltage, the diffusion current and the saturation current were found to be finite at T>T c , but almost zero at T≤T c . At T=78 K , the diffusion voltage of the diode YBa 2 Cu 3 O 7/n-type silicon was about 200 mV lower as compared to that of the reference diode YBa 2 Cu 3 O 6.5/n-type silicon. The observed phenomena are explained in terms of different charge carrier behavior in the superconducting ceramics above and below T c .
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Liu, Sikui, Zhanping Zhang, and Yuhong Qi. "Effect of Emulsifier on the Structure and Properties of Waterborne Silicone Antifouling Coating." Coatings 10, no. 2 (February 12, 2020): 168. http://dx.doi.org/10.3390/coatings10020168.
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Three-component waterborne silicone antifouling coatings, which could cured at room temperature, were prepared, respectively, with cationic (stearyl trimethyl ammonium bromide) or anionic (sodium dodecyl benzene sulfonate) silicone emulsion as a film-forming substance, γ-methacryloxypropyltrimethoxysilane as a curing agent and dibutyltin dilaurate as a catalyst. The effect of emulsifier on the structure and properties of silicone coating was studied. The results showed that the coating with cationic silicone emulsion had high crosslinking density, and its surface is smooth. The surface of the coating prepared by the anionic silicone emulsion is rough. Emulsifier type had no obvious effect on the surface free energy of the waterborne silicone coating. The coatings have the characteristics of low surface energy and excellent bacterial desorption properties. Stearyl trimethyl ammonium bromide in the cured coating can reduce the adhesion of marine bacteria on the coating surface. Both the emulsifiers can inhibit the activity of Navicula Tenera. The waterborne silicone coating prepared by cationic silicone emulsion has better comprehensive mechanical properties and antifouling performance.
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Khan, Madihah, Alyxandra Thiessen, I. Teng Cheong, Sarah Milliken, and Jonathan G. C. Veinot. "Investigation of Silicon Nanoparticle-Polystyrene Hybrids." Alberta Academic Review 2, no. 2 (September 15, 2019): 49–50. http://dx.doi.org/10.29173/aar60.
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Current LED lights are created with quantum dots made of metals like selenium, tellurium, and cadmium which can be toxic. Silicon is used as a non-toxic substance and is the second most abundant element in the earth's crust. When silicon is prepared at a nanometer size, unique luminesce optical properties emerge that can be tuned using sized surface chemistry. Therefore, silicon nanoparticles can be used as an alternative emitter for LED lights. To produce hydride-terminated silicon nanoparticles we must synthesize the particles. Hydrogen silsesquioxane (HSQ) is processed at 1100 °C for one hour causing Si to cluster and form a SiO2 matrix, also known as the composite. The composite is then manually crushed in ethanol. The solution is further ground using glass beads, then filtered to get the composite powder. The final step is the HF etching. The hydride-terminated particles are then functionalized using three different methods to synthesize silicon nanoparticle-polystyrene hybrids, which determine the magnitude of luminosity and the quality of the hybrids. We spin coat each method and results were analyzed. Method 1 uses heat to functionalize hydride-terminated silicon nanoparticles with styrene. This process also causes styrene to attach to styrene to form a polystyrene chain. Method 1 gave a homogeneous mixture which yielded a consistent, bright and homogenous film. In method 2, dodecyl-terminated silicon nanoparticles are mixed with premade polystyrene. While this method gave better control of the amount of silicon nanoparticles inside the polymer hybrid, a homogeneous mixture was not created due to the different structures of polystyrene and dodecyl chains. Method 3 has dodecyl-terminated silicon with in-situ styrene polymerization. It generated a homogeneous mixture. The in-situ polymerization stabilizes the particles, allowing for brighter luminescence. Because of the stability and lower molecular weight, the mixture was easier to dissolve. We concluded that the different methods resulted in different polymer molecular weights and this created distinct properties between the polymer hybrids when spin-coating.
Dissertations / Theses on the topic "Silicon substarte"
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Yu, chien an, and 俞建安. "The oxidation mechanism and the effect of nitrogen implanted silicon substarte." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/33867093547497387673.
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碩士長庚大學
電機工程研究所
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The MOSFET gate engineering becomes an increasingly important technology component in the overall transistor design. The demand for gate engineering has been driven by several technical concerns such as boron penetration, thin oxide reliability, and leakage current, etc. Traditional thin oxide growth methods have many problems when scaling down to deep submicron technique. A new fabrication technology for dual-gate CMOSFET’s with multiple gate oxide thicknesses has been proposed using nitrogen implantation into silicon substrates before growing thin thermal oxides. System on a chip (SOC) has gradually become the trend of CMOS technologies, where the circuit architecture is optimized under several constrains including speed, power dissipation, and memory retention time. The multiple-gate-oxide scheme is very helpful to achieve that goal. First, we investigated the oxidation model of gate oxide grown on nitrogen-implanted into Silicon substrate. In our experiment, using various nitrogen implant doses (5×1013 ~1×1015 cm-2) and energies (12,24keV), and different oxidation temperature(800~900℃) were used. We found that the oxidation rate is strongly dependent to the nitrogen concentration at Si and SiO2 interface. According to the profile and peak value shift of SIMS data in various conditions (including oxidation time), we change the parameter of Tsuprem4 thin oxidation model. The oxidation model of nitrogen implanted into silicon will be observed has developed. We present a detailed study of the effect of nitrogen implantation on device electrical characteristics and defect generation. We also observed that the new technology could reduce boron penetration effect and improve the ability of gate control over channel. The low field leakage current is not as good as the data presented in the literature (C. T. Liu et al in 1997), but it does not get worse when compared to the control wafer. The defect induced by nitrogen implantation is cause of oxidation rate variations. By the C-V measurement, at some regime of nitrogen dose (5×1013 ~1×1014 cm-2), the flat-band voltage shift increase with nitrogen implant dose. The dopant-like behavior of nitrogen could come from defect conduction mechanism or B-N bonding. On the other hand, the defect in the silicon induce by nitrogen implantation is not serious after thermal cycle. And the electron trap in the oxide near the interface may be induced by nitrogen incorporation into the oxide.
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Nevliudov, I., O. Chala, I. Botsman, O. Klymenko, and M. Vzhesnievskyi. "Automation of Mathematical Modeling of Physical and Technological Processes in the Electronic Devices Manufacture." Thesis, 2021. https://openarchive.nure.ua/handle/document/17949.
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The variant of automation of the mathematical modeling process for forecasting the technological process
parameters of manufacturing nano and microelectromechanical systems is proposed in the paper. For this task realization, a number of defects were identified and the causes of their occurrence were analyzed, as well as physical and technological transformations that occur in the substrates during technological processes. The software for automation of technological parameters forecasting process is developed and described.
Books on the topic "Silicon substarte"
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The substance of civilization: Materials and human history from the stone age to the age of silicon. New York: Arcade Pub., 1998.
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Sass, Stephen L. Substance of Civilization: Materials and Human History from the Stone Age to the Age of Silicon. Skyhorse Publishing Company, Incorporated, 2011.
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Sass, Stephen L. Substance of Civilization: Materials and Human History from the Stone Age to the Age of Silicon. Skyhorse Publishing Company, Incorporated, 2011.
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The Substance of Civilization: Materials and Human History from the Stone Age to the Age of Silicon. Arcade Publishing, 1999.
Find full textBook chapters on the topic "Silicon substarte"
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Marsmann, H. C., and F. Uhlig. "Substance Index." In Chemical Shifts and Coupling Constants for Silicon-29, 47–95. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-45278-2_4.
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Ball, Philip. "7. For all practical purposes: technologies of the elements." In The Elements: A Very Short Introduction, 139–57. Oxford University Press, 2004. http://dx.doi.org/10.1093/actrade/9780192840998.003.0007.
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‘For all practical purposes: technologies of the elements’ considers the variety that exists within the elements, and how they can be applied to our everyday lives. Iron and steel gave early armies the edge in battle, but the role of carbon in steel production was not understood until the eighteenth century. Silicon was used in glass for centuries, but its semiconducting properties make it the ideal substance for computer chips. The platinum group metals were unsuccessfully marketed as alternatives to silver, but now they are integral in catalytic converters. Palladium gained notoriety as a key ingredient of ‘cold fusion’, and rare earth metals are used in television screens.
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Xie, Xiang-Qun, Lirong Wang, Junmei Wang, Zhaojun Xie, Peng Yang, and Qin Ouyang. "In Silico Chemogenomics Knowledgebase and Computational System Neuropharmacology Approach for Cannabinoid Drug Research." In Neuropathology of Drug Addictions and Substance Misuse, 183–95. Elsevier, 2016. http://dx.doi.org/10.1016/b978-0-12-800634-4.00019-6.
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Jordan, David R., and Stephen R. Klapper. "Soft Tissue Fillers for Facial Aesthetics." In Surgery of the Eyelid, Lacrimal System, and Orbit. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780195340211.003.0038.
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The search for an ideal soft tissue filler to correct facial folds and wrinkles has gone on for at least 100 years. Many products have been tried, including mineral oil, paraffin, and liquid silicone, in an effort to improve soft tissue imperfections. Most of the early substances were abandoned due to a high incidence of complications, including chronic edema, granuloma formation, scarring, and ulceration. The ideal tissue filler should be biocompatible, noncarcinogenic, nonteratogenic, nonmigratory, and free of adverse reaction. The ideal filler should also be inexpensive and easy to use, require little preparation, and provide long-lasting, natural, and predictable results with minimal recovery time. Although no currently available injectable substance possesses all of these ideal attributes, many currently available products provide more-than-satisfactory results and have excellent safety profiles. The indications for injectable filler agents have largely evolved through a better understanding of facial aging, specifically soft tissue deflation typically noted between youth and middle age. The limitations of surgical procedures to correct soft tissue atrophy, as well as the possibility of delaying surgical procedures by early intervention with injectable fillers, have made these agents very valuable in improving the appearance of the aging face. With the continued improvement in products and techniques during recent years, the clinical results with fillers have become more predictable. As a result of this improvement, an increasing number of patients are seeking nonsurgical methods for correcting age-related changes to their facial skin and soft tissue. There are essentially two types of natural facial wrinkles (or rhytides): dynamic and static. They may occur separately or in combination. Dynamic wrinkles appear within the skin due to repeated contracture by the underlying muscles of facial expression. Static wrinkles are present regardless of facial dynamics and result from intrinsic changes in the components of the dermal ground substance and from extrinsic factors such as smoking, gravity, and sun exposure. The formation of both dynamic and static wrinkles is influenced by the quality of the natural collagen matrix within the dermal layers of the skin. For the most part, dynamic wrinkles are best treated with Botulinum toxin injections, particularly in the upper face.
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Chimowitz, Eldred H. "Critical Behaviour in Confined Systems." In Introduction to Critical Phenomena in Fluids. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780195119305.003.0013.
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The prediction of properties in complex materials is a problem of importance in many applications in chemical and materials engineering; by the term “complex material” we mean a heterogeneous substance, like a porous material containing a confined fluid. Such materials appear in many technological applications, including: (1) processes using supercritical fluids to dry porous aeorogels and thin films [1], (2) physical adsorption of trace components from gaseous effluents, (3) gas storage using microporous materials [2], and (4) chemical separation using inorganic membranes [3]. Inorganic membranes are often highly porous and randomly structured materials with large surface areas available for adsorption, a property that makes them useful in chemical separation and as catalyst supports. In addition to their heterogeneity, complex materials have another distinguishing characteristic that relates to the structure of the heterogeneity itself. Is it periodic, or is it dispersed throughout in some random fashion? These two situations are quite distinct and may, in each instance, show critical behavior for a confined fluid belonging to entirely different universality classes, an issue that to the present time is still unsettled in the literature. In this chapter, we investigate the critical properties of fluids confined in randomly structured host materials like that found in porous silicon. The main question we address is: how does confinement in a porous structure affect the critical point or phase behavior of a fluid mixture? Before investigating some of the more advanced ideas in this area, we look at the basic thermodynamics of interfaces, and the phenomenon of capillarity in a single idealized pore structure. This simple example provides the impetus for a more detailed study of confinement effects. Consider two phases in equilibrium separated by an interface. The total energy of the composite system is the sum of the energy of each phase plus the energy associated with the interface. In formulating the fundamental thermodynamic equation for energy in this system, we presume that the formation of an interface requires energy; therefore, the energy equation must reflect this fact.
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Fontani, Marco, Mariagrazia Costa, and Mary Virginia Orna. "The Forerunners of Celtium and Hafnium: Ostranium, Norium, Jargonium, Nigrium, Euxenium, Asium, and Oceanium." In The Lost Elements. Oxford University Press, 2014. http://dx.doi.org/10.1093/oso/9780199383344.003.0012.
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Of the naturally occurring nonradioactive elements, hafnium was the next to last to be discovered, preceding the discovery of rhenium by 3 years. It can boast of holding a very strange record: the number of claims for its discovery over the years is unequaled by any other element. This record was the cause of frustration for many scientists who, over the years, took turns in attempts to isolate it. The reason that hafnium remained undiscovered until 1922 lay not so much in that its presence in nature (long known to be quite scarce) wasn’t looked for, but in its peculiar chemical properties that bound it up intimately with zirconium. Toward the end of the 18th century, Martin Heinrich Klaproth melted some forms of yellow-green and red zirconium with sodium hydroxide and then digested the residue several times with hydrochloric and sulfuric acids to eliminate the extraneous silicon. The solution, thought to contain a number of elements, produced, upon addition of potassium carbonate, a generous precipitate. The oxide that Klaproth collected did not seem to belong to any known substance, and he called it terra zirconia. With the passing of the years, he and many other chemists, among them the renowned Jons Jacob Berzelius, determined the elemental composition of zircon and of its correlative minerals. Far from being simply ZrSiO4, zircon contained traces of iron, aluminum, nickel, cobalt, lead, bismuth, manganese, lithium, sodium, zinc, calcium, magnesium, and uranium and small amounts of the rare earths. Some impurities persistently resisted separation from zirconium oxide or zirconia and were taken erroneously for oxides of new elements (new earths). In 1825, Johann Friedrich August Breithaupt (1791–1873) reported the presence of a new element, ostranium, isolated from ostranite, a mineral similar to zircon. Twenty years later, the Swedish chemist, mineralogist, and metallurgist Lars Fredrik Svanberg (1805–78) announced the discovery of a new element. In his publication of 1845, he asserted that the zirconium oxide obtained from a variety of Siberian, Norwegian, and Indian zircon samples was in reality composed of two earths: one, zirconia, already noted, and another unknown earth.
Conference papers on the topic "Silicon substarte"
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Hu, Yu-Chen, and Kuan-Neng Chen. "Development and electrical performance of low temperature Cu-Sn/In bonding for 3D flexible substate integration." In 2016 IEEE Silicon Nanoelectronics Workshop (SNW). IEEE, 2016. http://dx.doi.org/10.1109/snw.2016.7578033.
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Jeong, Seungtaek, Subin Kim, Youngwoo Kim, Shinyoung Park, Hyunwook Park, Joungho Kim, Jae Hak Lee, and Jun Yeob Song. "Design and Analysis of Flexible Interconnects on an Extremely Thin Silicon Substate for Flexible Wearable Devices." In 2019 Joint International Symposium on Electromagnetic Compatibility, Sapporo and Asia-Pacific International Symposium on Electromagnetic Compatibility (EMC Sapporo/APEMC). IEEE, 2019. http://dx.doi.org/10.23919/emctokyo.2019.8893905.
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Ultarakova, А., N. Lokhova, and A. Yessengaziyev. "Silica removal from waste of ilmenite concentrate pyrometallurgical processing." In Challenges of Science. Institute of Metallurgy and Ore Beneficiation, Satbayev University, 2021. http://dx.doi.org/10.31643/2021.12.
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The article presents the study results for alkaline leaching of fine ilmenite concentrate dusts from electric smelting. The physical and chemical properties of the dusts were studied using chemical and instrumental analysis methods. The dust composition was determined, X-ray phase analysis showed that the dust sample substance is in the X-ray amorphous state, iron is present in the trivalent state, and silicon is bound to magnesium. The dust sample study using a scanning electron microscope showed that part of the titanium is bound in a hard-to-disclose anasovite encapsulated in amorphous silicon oxide. The leaching study of electric smelting dust with sodium hydroxide solutions included the study of the effect of sodium hydroxide concentration, process duration, temperature, S: L ratio. The optimal conditions for dust leaching from electric smelting of ilmenite concentrate have been established: temperature 80-90 °C, duration 90-120 min, ratio S: L = 1: 5, the concentration of sodium hydroxide solution 110-115 g/dm3. The silicon extraction degree into the solution under these conditions was 77.7%. The behavior of accompanying components of chromium, zinc, iron, and manganese during dust leaching was also studied. X-ray phase analysis of the cake after leaching shows almost complete amorphization of the leached product, the main phase is a solid solution of Fe2O3·TiO2.
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Bourell, David L., Phani Vallabhajosyula, Brooke Stevinson, Ssuwei Chen, and Joseph J. Beaman. "Rapid Manufacturing Using Infiltration Selective Laser Sintering." In ASME 2008 9th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2008. http://dx.doi.org/10.1115/esda2008-59084.
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Selective Laser Sintering (SLS) is tooless, computer-controlled layerwise additive manufacturing using a laser and a powder bed. The scanning laser locally melts the surface of a powder bed selectively, followed by deposition of a fresh layer of powder and repetition of the process. SLS has been developed for plastic powder. Creation of non-metallics and metal parts is more challenging. One approach is to mix the master powder with a transient binder. SLS melts the binder which wets the master powder, creating a green part. Subsequent post-processing is required to either remove the binder or convert it to a usable form. The last step is infiltration with a molten substance. Fundamentals of infiltration theory will be reviewed. A study of dimensional changes associated with various stages of processing reveals that overall linear dimensions vary less than one percent compared to the computer solid model. Several examples demonstrating the utility of an infiltration approach to freeform fabrication will be presented. These include silicon carbide with a phenolic binder, infiltrated with silicon; graphite with a phenolic binder infiltrated with epoxy; and tool steel with a proprietary low-ash binder infiltrated with cast iron.
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Watcharasing, Sunisa, Chularat Wattanakit, Saros Salakhum, Anittha Prasertsab, and Prapoj Kiattikomol. "Synthesis of Zeolites from Production Sand Waste: The Circular Model for Oil and Gas Exploration and Production." In Offshore Technology Conference Asia. OTC, 2022. http://dx.doi.org/10.4043/31420-ms.
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Abstract This project aims to convert production sand waste from oil & gas exploration & production process to be high value silica-based product, Zeolites, and explore opportunities to lower amount of sand waste disposal to landfill. This is one key item in Circular Model for Oil & Gas Exploration & Production. Zeolites is a microporous crystalline aluminosilicate material, which possess a superior characteristic in terms of high surface area. Therefore, it is widely utilized in many industries such as adsorbent, ion exchange, and catalysts in oil refining and petrochemical industry. In this work, various types of zeolites were synthesized from PTTEP production sand waste, to prove concept of turning sand waste to high value-added product, called zeolite. In normal operation, sand waste was sent to dispose as landfill about 50 Ton/annual. To synthesize zeolite from sand waste, there are three main steps, which are 1) Sand Pretreatment, 2) Silica Extraction, and 3) Zeolite Synthesis. Firstly, sand waste from petroleum production were pretreated by water and acid washing. Then, nanosilica was extracted out from pretreated sand by boiling the pretreated sand in NaOH solution at temperature 150 C for 4 hrs, then precipitate them to get the nanosilica substances. It was further used as a reactant source for zeolite synthesis. In the last step, the extracted silica was reacted with Structure Directing Agent (SDA); zeolite template, under optimal condition of hydrothermal treatment process to obtain zeolites product. Zeolites synthesis from production sand waste was firstly initiated and successfully achieved in lab phase, to prove of concept for extracting silica source as a substance for zeolite synthesis. Various types of zeolites (Silicalite-1, ZSM-5, Faujasite (FAU), Mordenite, and Zeolite A) can be synthesized from PTTEP sand waste with synthesis yield 80%, 68%, 85%, 40%, and 81%, respectively. This indicates that silica source from production sand waste can be utilized as a reactant source for zeolites synthesis. The next phase of prototype unit is under design phase, to allow unit can be operated more versatile, and automatically run. From this novel technology, it is expected to reduce an amount of production sand waste disposal out from separator to landfill about 50 Ton/year. The synthesized zeolites from prototype phase will be further applied in many potential applications such as an adsorbent in wastewater treatment process, as catalyst, and moisture adsorbent in oil & gas dehydration unit. New findings and requirements discovered during the prototype test will be used to iteratively optimize and improve the design of the sand to zeolites process for future industrial-scale implementation.
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Gernand, Jeremy M. "Particulate Matter: Fine and Ultrafine — How Emerging Data on Engineered Nanomaterials May Change How We Regulate Worker Exposures to Dust." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-53056.
Full textAbstract:
Currently in the United States, agencies responsible for regulations related to worker or public exposures to dust set rules based on a few general categories determined by gross particle size categories like PM10 (particles < 10 μm) and PM2.5 (particles < 2.5 μm) and the total mass of certain specific compounds (e.g., 3.5 mg/m3 of carbon black). Environmental health researchers however, have begun to focus on a new category of ultrafine particles (PM0.1; particles < 100 nm) as being more indicative of actual health risks in people. The emerging field of nanotoxicology meanwhile is providing new insights into how and why certain particles cause damage in the lungs by investigating the effects of exposure in animals to very well characterized engineered nanomaterials. Based on this recent research the National Institute of Occupational Safety and Health (NIOSH) has issued new recommended exposure limits (RELs) for carbon nanotubes (CNTs) and titanium dioxide nanoparticles that are 2–3 orders of magnitude more stringent than RELs for larger particles of the same or similar substance. It remains unclear at present how stringent future regulations may be for engineered and inadvertently created nanoparticles or ultrafine dusts. Nor is it clear whether verification methods to demonstrate compliance with these rules could or should be devised to differentiate between engineered and inadvertently created nanoparticles. This study presents a review of the history of dust regulation in the United States, how emerging data on the health risks of ultrafine particles and engineered nanoparticles is changing our understanding of the risks of inhaled dust, and how future rulemaking in regards to these and similar particulate materials may unfold. This review shows the extent to which rules on dust have become more stringent over time specifically in the case of diesel emissions and silica exposure, and indicates that new rules on worker exposure to ultrafine dusts or engineered nanomaterials may be expected in the United States within 5–10 years based on past experience on the time delay in connecting research on new hazards to regulatory intervention. Current research suggests there will be several challenges to compliance with these rules depending on the structure of the final rule and the development of detection technologies. Although the research on ultrafine dust control technologies appears to indicate that once rulemaking begins there may be no serious feasibility limits to controlling these exposures. Based on ongoing exposure studies, those industries likely to be most affected by a new rule on ultrafine dusts not specific to engineered nanomaterials will include transportation, mining, paper and wood products, construction, and manufacturing.