Artykuły w czasopismach: „Crystal growth and design”

1

Boons, Sofie. "Crystal Growing Design method: An investigation into the growing of crystals for jewellery designs". Craft Research 13, nr 2 (1.09.2022): 303–26. http://dx.doi.org/10.1386/crre_00081_1.

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Grown crystals are used for a range of novel innovations supporting a wide array of industries such as technology, medicine and electronics. Within the jewellery industry however, grown crystals are only used in a limited capacity and those of gemstone quality mainly as a surrogate for mined gemstones. They have remained largely underused, despite their potential sustainability credentials and the creative possibilities the incorporation of the process of crystal growth holds for jewellery designers. The bespoke growth of gemstone quality crystals could lead to highly unique jewellery designs which would result in higher consumer attachment. This in addition to the potentially more sustainable production of these stones would lead to overall more sustainable products. To address the barriers that are holding jewellery designers back from exploring the growth of crystals in their practice, and to address the knowledge gap that underpins this barrier, this article presents a practice-based exploration into the method of Crystal Growing Design for jewellery. Alongside reviewing a selection of the limited number of jewellery designers who have explored organic crystal growth, the article discusses the results of the practice-based explorations done. Three hypotheses derived from the characteristics and advantages of Growing Design were tested in three case studies and aimed to explore the design opportunities the method provides designers when (1) growing in situ either in designs or (2) around shapes or (3) when utilizing the grow-ability of the process as a feature. Because the growth of gemstone quality crystals requires more elaborate and high-cost equipment, sugar, alum and salt were experimented with as a prelude to further experimentation with the technique using gemstone grade crystals. Through utilizing an explorative Do-It-Yourself (DIY) approach, the author documents and discusses the opportunities and challenges presented by the incorporation of a crystal growth method into the jewellery design practice. The research article will additionally reflect on the DIY growth of these non-gemstone quality crystals as a meaningful learning process for jewellery designers wishing to gain a deeper understanding of crystal growth. The DIY growth of crystals can be considered a valuable tinkering process to investigate design ideas. Which is particularly relevant since the method of growing crystals holds creative potential when designing jewellery in collaboration with crystal growers, or through incorporating gemstone crystal growth processes, which are the topic of the author’s overarching Ph.D. research.

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Choi, Jung Woo, Jung Gyu Kim, Byung Kyu Jang, Sang Ki Ko, Myung Ok Kyun, Jung Doo Seo, Kap Ryeol Ku, Jeong Min Choi i Won Jae Lee. "Modified Hot-Zone Design for Large Diameter 4H-SiC Single Crystal Growth". Materials Science Forum 963 (lipiec 2019): 18–21. http://dx.doi.org/10.4028/www.scientific.net/msf.963.18.

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6-inch 4H-SiC single crystal was grown with modified hot-zone design for large diameter crystal. The simulation data confirmed reduced temperature gradient between center and edge region of growing front, and actual growth experiment exhibited that SiC crystal with good quality was obtained with modified hot-zone design without any quality degradation in edge region of bulk crystal. Based on the mapping measurement of FWHM (Full width at half maximum) value in X-ray rocking curve, the crystal quality of SiC crystals from middle and top region of grown ingot was observed to be almost identical. Furthermore, various properties of SiC crystal grown with modified hot-zone design have been systematically investigated.

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Derby, Jeffrey J. "Theoretical Modeling of Czochralski Crystal Growth". MRS Bulletin 13, nr 10 (październik 1988): 29–35. http://dx.doi.org/10.1557/s0883769400064162.

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The growth of single crystals with precisely controlled properties is one of the most demanding goals of modern materials processing, and its realization depends on the application of fundamentals from solid-state physics, chemistry, thermodynamics, and transport phenomena. Bulk semiconductor substrates and many high-power solid-state laser host materials are typically produced by solidification from the melt. The quality of the crystals produced this way hinges on process conditions which are predominantly determined by the transport of heat, mass, and momentum in the melt and crystal. Accurate modeling of melt crystal growth promises to enhance our understanding of existing systems and improve the design and control of future processes, thereby accelerating the development of advanced materials and devices.Theoretical modeling is often the only way to probe the complex interactions which characterize melt crystal growth, especially the effects of process changes on internal features of growth that cannot be directly measured on-line, such as the shape of the melt/crystal interface or temperature gradients within the growing crystal. In this way, computer simulation can serve as a design tool for developing control strategies and process innovations. Further, modeling serves as a test-bed for theoretical experiments which extend our knowledge of how fundamental physical phenomena govern the process.This report attempts to provide a glimpse of how analysis and modeling have impacted the understanding of Czochralski (CZ) crystal growth. The reader is referred to several excellent reviews for more in-depth information regarding melt crystal growth modeling.

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Steed, Jonathan W. "Crystal Growth & Design in Lockdown". Crystal Growth & Design 21, nr 1 (6.01.2021): 1–2. http://dx.doi.org/10.1021/acs.cgd.0c01484.

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Li, Shi, Jihe Zhao, Xiao Wang, Zhihua Li, Xuefeng Gui, Jiwen Hu, Shudong Lin i Yuanyuan Tu. "Preparation of polyethylene oxide single crystals via liquid gating technology and morphology design strategy". Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 77, nr 5 (18.09.2021): 819–23. http://dx.doi.org/10.1107/s2052520621008076.

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A novel type of liquid gating technology has been developed to prepare a polyethylene oxide (PEO) single-crystal film, and the crystal growth was observed via atomic force microscopy. The self-seeding method has been widely used in the preparation of polymer single crystals, but the mechanism through which single polymer crystals are formed via the combination of liquid gating technology and the self-seeding method remains unclear. To elucidate the mechanism of this process, a series of experiments were conducted in which a dilute polymer solution was sprayed onto a mica substrate to form a single-crystal film through liquid gating technology to study the effect of the crystallization time on the morphology of a thiol PEO (mPEO-SH) crystal. Based on this research, it was found that liquid gating helps to prevent twinning during crystal growth. The combination of liquid gating and self-seeding technology thus provides a new strategy for polymer single-crystal growth.

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Turner, T. D., T. T. H. Nguyen, P. Nicholson, G. Brown, R. B. Hammond, K. J. Roberts i I. Marziano. "A temperature-controlled single-crystal growth cell for the in situ measurement and analysis of face-specific growth rates". Journal of Applied Crystallography 52, nr 2 (28.03.2019): 463–67. http://dx.doi.org/10.1107/s1600576719002048.

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The design and construction of a growth cell for the precision measurement of face-specific single-crystal growth rates are presented. Accurate mechanical drawings in SolidWorks of the cell and individual components are provided, together with relevant construction models. A general methodology for its use in the measurement of single-crystal growth rates and their underpinning growth mechanism is presented and illustrated with representative data provided for the crystal growth of the {011} and {001} faces of RS-ibuprofen single crystals grown in ethanolic solutions. Analysis of these data highlights the utility of the methodology in morphological model development and crystallization process design.

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Zhang, Shengtao, Guoqing Fu, Hongda Cai, Junzhi Yang, Guofeng Fan, Yanyu Chen, Tie Li i Lili Zhao. "Design and Optimization of Thermal Field for PVT Method 8-Inch SiC Crystal Growth". Materials 16, nr 2 (12.01.2023): 767. http://dx.doi.org/10.3390/ma16020767.

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As a wide bandgap semiconductor material, silicon carbide has promising prospects for application. However, its commercial production size is currently 6 inches, and the difficulty in preparing larger single crystals increases exponentially with size increasing. Large-size single crystal growth is faced with the enormous problem of radial growth conditions deteriorating. Based on simulation tools, the physical field of 8-inch crystal growth is modeled and studied. By introducing the design of the seed cavity, the radial temperature difference in the seed crystal surface is reduced by 88% from 93 K of a basic scheme to 11 K, and the thermal field conditions with uniform radial temperature and moderate temperature gradient are obtained. Meanwhile, the effects of different processing conditions and relative positions of key structures on the surface temperature and axial temperature gradients of the seed crystals are analyzed in terms of new thermal field design, including induction power, frequency, diameter and height of coils, the distance between raw materials and the seed crystal. Meanwhiles, better process conditions and relative positions under experimental conditions are obtained. Based on the optimized conditions, the thermal field verification under seedless conditions is carried out, discovering that the single crystal deposition rate is 90% of that of polycrystalline deposition under the experimental conditions. Meanwhile, an 8-inch polycrystalline with 9.6 mm uniform deposition was successfully obtained after 120 h crystal growth, whose convexity is reduced from 13 mm to 6.4 mm compared with the original scheme. The results indicate that the optimized conditions can be used for single-crystal growth.

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Li, Jinjin, Carl J. Tilbury, Seung Ha Kim i Michael F. Doherty. "A design aid for crystal growth engineering". Progress in Materials Science 82 (wrzesień 2016): 1–38. http://dx.doi.org/10.1016/j.pmatsci.2016.03.003.

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Batur, Celal, Walter M. B. Duval i Robert J. Bennett. "Control and design of crystal growth furnace". ISA Transactions 38, nr 1 (styczeń 1999): 73–85. http://dx.doi.org/10.1016/s0019-0578(98)00043-3.

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Cabric, B., i T. Pavlovic. "Apparatus for crystal growth". Journal of Applied Crystallography 38, nr 2 (11.03.2005): 368–69. http://dx.doi.org/10.1107/s002188980500511x.

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The design of an apparatus based on Bridgman's method, enabling visualization of the growth process and regulation of the crystallization rate, for obtaining single crystals from a melt in a school laboratory is presented. Conditions for obtaining single crystals of several substances are given.

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Ku, Kap Ryeol, Jung Kyu Kim, Jung Doo Seo, Ju Young Lee, Myung Ok Kyun, Won Jae Lee, Geun Hyoung Lee, Il Soo Kim i Byoung Chul Shin. "High Quality SiC Crystals Grown by the Physical Vapor Transport Method with a New Crucible Design". Materials Science Forum 527-529 (październik 2006): 83–86. http://dx.doi.org/10.4028/www.scientific.net/msf.527-529.83.

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SiC single crystal ingots grown by sublimation physical vapor transport (PVT) technique were prepared and then the SiC crystal quality with varying crucible design employing a guide tube and tantalum foil was systematically investigated. The growth rate of 2-inch SiC crystal grown by these crucible designs was about 0.3 mm/hr. The n-type and p-type 2”-SiC single crystals exhibiting the polytype of 6H-SiC were successfully fabricated. The doping concentration level of below ~1017/cm3 was extracted from the absorption spectrum and Hall measurement. The densities of micropipes and inclusions in SiC crystal boules grown using the graphite/Ta foil double layer guide tube were significantly decreased. Finally we improved crystal quality through the introduction of new crucible design.

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Jung, Jung Young, Sang Il Lee, Mi Seon Park, Doe Hyung Lee, Hee Tae Lee, Won Jae Lee, Soon Ku Hong i Myong Chuel Chun. "The Effect of Modified Crucible Design and Seed Attachment on SiC Crystal Grown by PVT". Materials Science Forum 740-742 (styczeń 2013): 77–80. http://dx.doi.org/10.4028/www.scientific.net/msf.740-742.77.

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The present research was focused to investigate the effect of internal crucible design that influenced the 4H-SiC crystal growth onto a 6H-SiC seed by PVT method. The crucible design was modified to produce a uniform radial temperature gradient in the growth cell. The seed attachment was also modified with a use of polycrystalline SiC plate. The crystal quality of 4H-SiC single crystals grown in modified crucible and grown with modified seed attachment was revealed to be better than that of crystal grown in conventional crucible. The full width at half maximum (FWHM) values of grown SiC crystals in the conventional crucible, the modified seed attachment and the modified crucible were 285 arcsec, 134 arcsec and 128 arcsec, respectively. The micropipe density (MPD) of grown SiC crystals in the conventional crucible, the modified seed attachment and the modified crucible were 101ea/cm^2, 81ea/cm^2 and 42ea/cm^2, respectively.

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13

Sun, Congting, i Dongfeng Xue. "Chemical bonding theory of single crystal growth and its application to crystal growth and design". CrystEngComm 18, nr 8 (2016): 1262–72. http://dx.doi.org/10.1039/c5ce02328a.

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Schmalenberg, Mira, Stephanie Kreis, Lena K. Weick, Christian Haas, Fabian Sallamon i Norbert Kockmann. "Continuous Cooling Crystallization in a Coiled Flow Inverter Crystallizer Technology—Design, Characterization, and Hurdles". Processes 9, nr 9 (29.08.2021): 1537. http://dx.doi.org/10.3390/pr9091537.

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Continuous small-scale production is currently of utmost interest for fine chemicals and pharmaceuticals. For this purpose, equipment and process concepts in consideration of the hurdles for solids handling are required to transfer conventional batch processing to continuous operation. Based on empirical equations, pressure loss constraints, and an expandable modular system, a coiled flow inverter (CFI) crystallizer with an inner diameter of 1.6 mm was designed. It was characterized concerning its residence time behavior, tested for operation with seed crystals or an ultrasonic seed crystal unit, and evaluated for different purging mechanisms for stable operation. The residence time behavior in the CFI corresponds to ideal plug flow behavior. Crystal growth using seed crystals was demonstrated in the CFI for two amino acids. For fewer seed crystals, higher crystal growth rates were determined, while at the same time, secondary nucleation was observed. Feasibility for the interconnection of a sonicated seeding crystal unit could be shown. However, the hurdles are also identified and discussed. Prophylactic flushing combined with a photosensor for distinguishing between solvent and suspension phase can lead to stable and resource-efficient operation. The small-scale CFI technology was investigated in detail, and the limits and opportunities of the technology are presented here.

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Liu, Zenghui, Hua Wu, Jian Zhuang, Gang Niu, Nan Zhang, Wei Ren i Zuo-Guang Ye. "High Curie temperature bismuth-based piezo-/ferroelectric single crystals of complex perovskite structure: recent progress and perspectives". CrystEngComm 24, nr 2 (2022): 220–30. http://dx.doi.org/10.1039/d1ce00962a.

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The recent progress in high TC bismuth-based piezo-/ferroelectric single crystals is reviewed in terms of materials design, crystal growth, physical properties, crystal chemistry, and complex domain structures, and the future perspectives are discussed.

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Tian, Maozhang, Xi Chen, Qun Zhang, Xinyuan Zou, Desheng Ma, Jiaming Xuan, Wentao Wang i Meiwen Cao. "Peptide-Mediated Synthesis of Zeolitic Imidazolate Framework-8: Effect of Molecular Hydrophobicity, Charge Number and Charge Location". Nanomaterials 11, nr 10 (12.10.2021): 2665. http://dx.doi.org/10.3390/nano11102665.

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Three amphiphilic peptides with varied molecular hydrophobicity, charge number and charge location have been designed as regulators to modulate the crystal growth of zeolitic imidazolate framework-8 (ZIF-8). All three peptides can interact with ZIF-8 to inhibit {100} facet growth and produce truncated cubic crystals. The peptide’s molecular hydrophobicity plays a dominant role in defining the final morphology and size of the ZIF-8 crystals. The peptides with less charge and higher hydrophobicity can promote nuclei formation and crystal growth to give smaller ZIF-8 crystals. However, the charge located in the center of the molecular hydrophobic region has little effect on the crystal nucleation and growth due to the shielding of its charge by molecular aggregation. The study provides insights into the effect of molecular charge and hydrophobicity on ZIF-8 crystal growth and is helpful for guiding the molecular design for regulating the synthesis of metal-organic framework materials.

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Harada, S., Goki Hatasa, Kenta Murayama, Tomohisa Kato, M. Tagawa i Toru Ujihara. "Solvent Design for High-Purity SiC Solution Growth". Materials Science Forum 897 (maj 2017): 32–35. http://dx.doi.org/10.4028/www.scientific.net/msf.897.32.

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In order to design a solvent for high-purity SiC solution growth, the impurity incorporation and the carbon solubility of various solvent materials have been investigated. Among the transition metal elements, the impurity elements of Cr, Ti, V and Hf are more readily incorporate during the solution growth than the other transition metal elements. The thermodynamic calculation revealed that the Y-Si solvent has relatively large carbon solubility, which is comparable to the Cr-Si and Ti-Si solvents often used in the solution growth of bulk SiC crystals. From these results, the Y-Si solvent is expected to be a suitable solvent for the high-purity SiC solution growth. Furthermore, we have demonstrated that the Y-Si solvent can achieve lower incorporation of metal impurity in the grown crystal than the Cr-Si solvent maintaining the growth rate.

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Jang, Byung Kyu, Jong Hwi Park, Jung Woo Choi, Eunsu Yang, Jung Gyu Kim, Sang Ki Ko, Myung Ok Kyun, Kap Ryeol Ku, Yeon Suk Jang i Won Jae Lee. "Modified Hot-Zone Design of Growth Cell for Reducing the Warpage of 6”-SiC Wafer". Materials Science Forum 1004 (lipiec 2020): 32–36. http://dx.doi.org/10.4028/www.scientific.net/msf.1004.32.

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The modified hot-zone design, consisting of a new design and new materials for the backside of SiC seed holder was adopted for reducing stress in grown SiC crystal ingot and for reducing the warpage of 6-inch SiC wafer. Crucible lid on the backside of SiC seed holder was designed to be movable during the growth process. Based on the warp value and mapping measurement of FWHM (Full width at half maximum) value in X-ray rocking curve, the crystal quality of SiC crystals grown with new hot-zone design was observed to be better than conventional design.

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Li, K., i W. R. Hu. "Magnetic field design for floating zone crystal growth". Journal of Crystal Growth 230, nr 1-2 (sierpień 2001): 125–34. http://dx.doi.org/10.1016/s0022-0248(01)01331-8.

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Kamaruddin, W. H. A., Hamdan Hadi Kusuma i Zuhairi Ibrahim. "Effect of New Thermal Insulation to the Growth of LiNbO₃ Single Crystal by Czochralski Method". Advanced Materials Research 701 (maj 2013): 108–12. http://dx.doi.org/10.4028/www.scientific.net/amr.701.108.

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Single crystal of LiNbO3has been successfully grown by the Czochralski method in an air atmosphere with a r.f heating crystal growth system namely Automatic Diameter Control Crystal Growth System (ADC-CGS). This paper reports on the effect of new thermal insulation on the growth process of LiNbO3single crystal. The effect of hot zone thermal insulation design was investigated. The conditions required to grow high quality LiNbO3single crystals are described. A set of crystal growth processes were conducted with the rotation rate of the seed at 15 rpm and the pulling rate at 2.0 mm/hr kept constant. All of the runs were grown along <104> orientation. To control the diameter of the crystal, we have to alter the thermal environment inside the hot zone. In other words, during the crystal growth we have to increase the control power to get smaller diameter and decrease the control power to get larger diameter.

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Black, Simon N., Adrian Hutchinson i Roger J. Davey. "Concerning the selection of crystallization modifiers for non-hydrogen bonded systems: the case of benzophenone". CrystEngComm 23, nr 5 (2021): 1281–93. http://dx.doi.org/10.1039/d0ce01547d.

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Choi, Si Young, i Suk Joong L. Kang. "Control of Boundary Structure and Grain Growth for Microstructural Design". Materials Science Forum 475-479 (styczeń 2005): 3891–96. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.3891.

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The design of microstructure in materials, ranging from ultrafine, moderately sized, duplex to single crystalline, has long been a challenging subject to material scientists. A basic means to achieve this goal is related to the control of grain growth. Taking BaTiO3 as a model system, this investigation shows that control of grain boundary structure between rough and faceted and control of initial grain size can allow us to achieve the goal. When the grain boundary is rough, normal grain growth occurs with a moderate rate. On the other hand, for faceted boundaries, either abnormal grain growth or grain growth inhibition occurs resulting in a duplex grain structure or fine-grained structure, respectively. Growth of single crystals is also possible when the boundary is faceted. During crystal growth amorphous films can form and thicken at dry grain boundaries above the eutectic temperature. As the film thickness increases, the growth rate of the crystals is reduced. This observed growth behavior of grains with boundary structure is explained in terms of the difference in mobility between the two types of boundaries. The results demonstrate the basic principles of obtaining various microstructures from the same material.

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Dropka, Natasha, Xia Tang, Gagan Kumar Chappa i Martin Holena. "Smart Design of Cz-Ge Crystal Growth Furnace and Process". Crystals 12, nr 12 (5.12.2022): 1764. http://dx.doi.org/10.3390/cryst12121764.

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The aim of this study was to evaluate the potential of the machine learning technique of decision trees to understand the relationships among furnace design, process parameters, crystal quality, and yield in the case of the Czochralski growth of germanium. The ultimate goal was to provide the range of optimal values of 13 input parameters and the ranking of their importance in relation to their impact on three output parameters relevant to process economy and crystal quality. Training data were provided by CFD modelling. The variety of data was ensured by the Design of Experiments method. The results showed that the process parameters, particularly the pulling rate, had a substantially greater impact on the crystal quality and yield than the design parameters of the furnace hot zone. Of the latter, only the crucible size, the axial position of the side heater, and the material properties of the radiation shield were relevant.

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Gevelber, M. A., i G. Stephanopoulos. "Control and System Design for the Czochralski Crystal Growth Process". Journal of Dynamic Systems, Measurement, and Control 115, nr 1 (1.03.1993): 115–21. http://dx.doi.org/10.1115/1.2897385.

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An expanded set of control objectives is proposed for the Czochralski crystal growth process. Consideration of the thermal stress near the interface yields an operating regime specification in terms of interface shape. A lumped parameter model is used to determine the performance of alternate inputs and outputs. Based on these considerations, a new control structure is proposed to maintain crystal diameter, interface shape, and thermal gradients throughout the batch growth cycle. The performance of alternative control structures are evaluated.

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Wang, Xiangmei, Zeliang Gao, Chunyan Wang, Xiaojie Guo, Youxuan Sun, Yu Jia i Xutang Tao. "Design, growth, and characterization of Y2Mo4O15 crystals for Raman laser applications". RSC Advances 11, nr 2 (2021): 1164–71. http://dx.doi.org/10.1039/d0ra08609f.

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Rogers, Robin D. "Crystal Growth & Design Around the World in 2012". Crystal Growth & Design 12, nr 1 (4.01.2012): 1–2. http://dx.doi.org/10.1021/cg201654d.

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Srinivasan, A., C. Batur, R. Veillette, B. N. Rosenthal i W. M. B. Duval. "Projective control design for multi-zone crystal growth furnace". IEEE Transactions on Control Systems Technology 2, nr 2 (czerwiec 1994): 142–47. http://dx.doi.org/10.1109/87.294337.

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Sun, Congting, i Dongfeng Xue. "Crystal Growth and Design of Sapphire: Experimental and Calculation Studies of Anisotropic Crystal Growth upon Pulling Directions". Crystal Growth & Design 14, nr 5 (22.04.2014): 2282–87. http://dx.doi.org/10.1021/cg401867c.

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Kang, Suk Joong L., Yang Il Jung i Kyoung Seok Moon. "Principles of Microstructural Design in Two-Phase Systems". Materials Science Forum 558-559 (październik 2007): 827–34. http://dx.doi.org/10.4028/www.scientific.net/msf.558-559.827.

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When a polycrystal is in chemical equilibrium, the microstructure evolves as a result of grain growth under the capillary driving force arising from the interface curvature. As the growth rate of an individual grain is the product of the interface mobility and the driving force, the growth of the grain can be controlled by changing these two parameters. According to crystal growth theories, the growth of a crystal with a rough interface is governed by diffusion and its interface mobility is constant. In-contrast, the growth of a crystal with faceted interfaces is governed by the interface reaction and diffusion for driving forces below and above a critical value, respectively. As the growth rate is nonlinear for the regime of interface reaction control, the grain growth is nonstationary with annealing time. Calculations reveal that the types of nonstationary growth behavior including pseudo-normal, abnormal, and stationary are governed by the relative value of the maximum driving force, gmax, to the critical driving force for appreciable growth, gc. Recent experimental observations showing the effects of critical processing parameters on microstructural development also support the theoretical prediction. The principles of microstructural design are deduced in terms of the coupling effects of gmax and gc.

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Moreno, Abel, i Manuel Soriano-García. "Crystal-growth kinetics of protein single crystals along capillary tubes in the gel-acupuncture technique". Acta Crystallographica Section D Biological Crystallography 55, nr 2 (1.02.1999): 577–80. http://dx.doi.org/10.1107/s0907444998013985.

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In attempts to obtain protein crystals of a sufficient size for structural studies, lack of knowledge of the physicochemical properties of protein solutions and of their crystal-growth behaviour lead to a bottleneck for drug design as well as for X-ray crystallography. Most formal investigations on crystal-growth phenomena have been focused on equilibrium studies, where the protein is soluble, and on the kinetics of crystal growth, which is related to both nucleation and crystal-growth phenomena. The aim of this work is to measure the crystal-growth rate along a capillary tube used as a growing cell. These experiments were carried out using the gel-acupuncture technique [García-Ruiz et al. (1993). Mater. Res. Bull. 28, 541–546; García-Ruiz & Moreno (1994). Acta Cryst. D50, 484–490; García-Ruiz & Moreno (1997). J. Cryst. Growth, 178, 393–401]. Crystal-growth investigations took place using lysozyme and thaumatin I as standard proteins. The maximum average growth rate obtained in the lower part of the capillary tube was about 35 Å s−1 and the minimum average growing rate in the upper part of the capillary tube was about 8 Å s−1. The crystal-growth rate as a function of the supersaturation was experimentally estimated at a constant height along the capillary tube.

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Kim, Jung Kyu, Kap Ryeol Ku, Dong Jin Kim, Sang Phil Kim, Won Jae Lee, Byoung Chul Shin, Geun Hyoung Lee i Il Soo Kim. "SiC Crystal Growth by Sublimation Method with Modification of Crucible and Insulation Felt Design". Materials Science Forum 483-485 (maj 2005): 47–50. http://dx.doi.org/10.4028/www.scientific.net/msf.483-485.47.

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SiC crystal boules with different shapes were prepared using sublimation physical vapor transport technique (PVT) and then their crystal quality was systematically investigated. The temperature distribution in the growth system and the crystal shape were controlled by modification of crucible and insulation felt design, which was successfully simulated using “Virtual Reactor” for flat structure design and concave structure design. The SiC polytype proved to be the n-type 6H-SiC from the typical absorption spectrum of SiC crystal. The defect density of SiC crystal boules with concave structure was slightly lower than that of flat structure and the crystal quality of SiC crystal boules with both flat structure and concave structure was significantly improved as the SiC crystal grows during the PVT methods.

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Qin, Zuoyan, Wenhao Chen, Danxia Deng, Zhenhua Sun, Baikui Li, Ruisheng Zheng i Honglei Wu. "Simulation and Experiment for Growth of High-Quality and Large-Size AlN Seed Crystals by Spontaneous Nucleation". Sensors 20, nr 14 (15.07.2020): 3939. http://dx.doi.org/10.3390/s20143939.

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Seed crystals are the prerequisite for the growth of high quality and large size aluminum nitride (AlN) single crystal boules. The physical vapor transport (PVT) method is adopted to grow AlN seed crystal. However, this method is not available in nature. Herein, the temperature field distribution in the PVT furnace was simulated using the numerical analysis method to obtain free-standing and large-size seeds. The theoretical studies indicate that the temperature distribution in the crucible is related to the crucible height. According to the theory of growth dynamics and growth surface dynamics, the optimal thermal distribution was achieved through the design of a specific crucible structure, which is determined by the ratio of top-heater power to main-heater power. Moreover, in our experiment, a sole AlN single crystal seed with a length of 12 mm was obtained on the tungsten (W) substrate. The low axial temperature gradient between material source and substrate can decrease the nucleation rate and growth rate, and the high radial temperature gradient of the substrate can promote the expansion of crystal size. Additionally, the crystallinity of the crystals grown under different thermal field conditions are analyzed and compared. The Raman results manifest the superiority of the thermal inversion method in the growth of high quality AlN single crystal.

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Warzecha, Monika, Alastair J. Florence i Peter G. Vekilov. "The Ambiguous Functions of the Precursors That Enable Nonclassical Modes of Olanzapine Nucleation and Growth". Crystals 11, nr 7 (26.06.2021): 738. http://dx.doi.org/10.3390/cryst11070738.

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One of the most consequential assumptions of the classical theories of crystal nucleation and growth is the Szilard postulate, which states that molecules from a supersaturated phase join a nucleus or a growing crystal individually. In the last 20 years, observations in complex biological, geological, and engineered environments have brought to light violations of the Szilard rule, whereby molecules assemble into ordered or disordered precursors that then host and promote nucleation or contribute to fast crystal growth. Nonclassical crystallization has risen to a default mode presumed to operate in the majority of the inspected crystallizing systems. In some cases, the existence of precursors in the growth media is admitted as proof for their role in nucleation and growth. With the example of olanzapine, a marketed drug for schizophrenia and bipolar disorder, we demonstrate that molecular assemblies in the solution selectively participate in crystal nucleation and growth. In aqueous and organic solutions, olanzapine assembles into both mesoscopic solute-rich clusters and dimers. The clusters facilitate nucleation of crystals and crystal form transformations. During growth, however, the clusters land on the crystal surface and transform into defects, but do not support step growth. The dimers are present at low concentrations in the supersaturated solution, yet the crystals grow by the association of dimers, and not of the majority monomers. The observations with olanzapine emphasize that detailed studies of the crystal and solution structures and the dynamics of molecular association may empower classical and nonclassical models that advance the understanding of natural crystallization, and support the design and manufacture of promising functional materials.

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Li, Jingjie, Jiachen Wang i Changmeng Liu. "The process and mechanical properties of GH4169 columnar crystals fabricated by wire arc additive manufacturing". Advances in Engineering Technology Research 1, nr 1 (17.05.2022): 259. http://dx.doi.org/10.56028/aetr.1.1.259.

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Wire- Arc Additive manufacture (WAAM) has been widely applied in metal field to control metal structure and microstructure. GH4169 is well fit to the WAAM due to its excellent weldability. While the columnar crystal has greater growth advantage than equiaxed crystal, so the superalloy GH4169 whose grain boundary induce its high temperature mechanical property will have fewer boundaries that can increase the property. While the shape of AM sample can be controlled, growth direction of columnar crystal can be adjusted through the heating method. If t growth directions of columnar crystals are consistent, the number of grain boundaries well induce largely. We can use different heating method and compare the result of growth direction. While the temperature environment at the top which decides the growth direction fit the requestion of growth direction, we can get the columnar that grows as we design.

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35

Luo, Hao, Xuefeng Han, Yuanchao Huang, Deren Yang i Xiaodong Pi. "Numerical Simulation of a Novel Method for PVT Growth of SiC by Adding a Graphite Block". Crystals 11, nr 12 (18.12.2021): 1581. http://dx.doi.org/10.3390/cryst11121581.

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SiC crystal is an excellent substrate material for high power electronic devices and high-frequency electronic devices. Being cost-effective and defect-free are the two biggest challenges at present. For the physical vapor transport (PVT) growth of a SiC single crystal, SiC powder is used as the source material, which determines the cost and the quality of the crystal. In this paper, we propose a new design in which graphite blocks are substituted for the non-sublimated SiC powder. Temperature distribution in the SiC powder, the evolution of the SiC powder, and the vapor transport are investigated by using finite element calculations. With the addition of graphite blocks, the utilization and sublimation rate of SiC powder is higher. In addition, the reverse vapor transport above the SiC powder is eliminated. This design provides a new idea to reduce the cost of SiC crystals in industrialization.

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Choi, Su Hun, Young Gon Kim, Yun Ji Shin, Seong Min Jeong, Myung Hyun Lee, Chae Young Lee, Jeong Min Choi, Mi Seon Park, Yeon Suk Jang i Won Jae Lee. "The Effect of Stepped Wall of the Graphite Crucible in Top Seeded Solution Growth of SiC Crystal". Materials Science Forum 924 (czerwiec 2018): 27–30. http://dx.doi.org/10.4028/www.scientific.net/msf.924.27.

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The crucible design having a stepped wall was introduced for increasing the growth rate of SiC crystal without metal addition in top-seeded solution growth (TSSG) method. The numerical simulation confirmed that new crucible design to increase the solvent-crucible interface could definitely change the temperature distribution and increase the carbon concentration. The simulation result, SiC single crystals were grown with Si solvent at 1900°C using a normal crucible and a stepped crucible to investigate the effect of crucible design having a stepped wall. Grown SiC layers were analyzed using Optical microscopy and Raman spectra. The growth rate in the stepped crucible was finally 66um/h observed.

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37

Perlovich, German. "Melting points of one- and two-component molecular crystals as effective characteristics for rational design of pharmaceutical systems". Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 76, nr 4 (21.07.2020): 696–706. http://dx.doi.org/10.1107/s2052520620007362.

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Based on the review of the literature results the database of the fusion temperatures of two-component molecular crystals (1947 co-crystals) and individual components thereof was built up. To improve the design of co-crystals with predictable melting temperatures, the correlation equations connecting co-crystals and individual components melting points were deduced. These correlations were discovered for 18 co-crystals of different stoichiometric compositions. The correlation coefficients were analysed, and the conclusions about the main/determinative and slave components of a co-crystal were made. The comparative analysis of the melting points of co-crystals composed from the same components but with different stoichiometry showed a co-crystal melting temperature growth when increasing the content of a high-melting component. The differences in the melting temperatures were determined and discussed for the following: (a) monotropic polymorphic forms, (b) two-component crystals with the same composition and different stoichiometry, and (c) two-component crystals based on racemates and enantiomers. The database analysis revealed the active pharmaceutical ingredients (APIs) and co-formers (CFs) more particularly used for co-crystal design. The approach based on an efficacy parameter allowing the prediction of co-crystals with melting points lower than those of individual compounds was developed.

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Zhang, Hui, Lili Zheng i Haisheng Fang. "Hot zone design for controlled growth to mitigate cracking in laser crystal growth". Journal of Crystal Growth 318, nr 1 (marzec 2011): 695–99. http://dx.doi.org/10.1016/j.jcrysgro.2010.11.130.

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Dai, Feng Yan, Wen Gang Ji i Jian Shu Cao. "Design and Analysis of Ultra-Low Speed Movement Equipment System". Applied Mechanics and Materials 130-134 (październik 2011): 1475–79. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.1475.

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Czochralski lifting device is the key equipment for crystal growth. Due to laser crystal growth mechanism could decide its slow growth speed, so Lifting device is required to operate under the ultra-low speed situation chronically. According to shock, shake, fraction and crawl of movement system affected speed stability, the paper carries out a nobel design to laser Czochralski lifting system through alternated servo technology and its precision is analyzed comprenshensively. The long-term experimental data showed by using changed plus PID control method that the system has high precision and better reliability and it is suitable to grow large-size laser crystal. Meanwhile, the design system makes use of common spare parts and can meet the requirements for large scale industrialization.

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40

de Sandro, J. P., i A. Chevy. "Novel design of graphite crucible for AgGaSe2 single-crystal growth". Journal of Crystal Growth 144, nr 1-2 (listopad 1994): 65–69. http://dx.doi.org/10.1016/0022-0248(94)90011-6.

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Rabeh, Wael, i Joel Bernstein. "Crystal Growth to Foster Inquiry–Based Learning: First Year Science Laboratory". Acta Crystallographica Section A Foundations and Advances 70, a1 (5.08.2014): C1383. http://dx.doi.org/10.1107/s2053273314086161.

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Crystals play an important and ubiquitous role in our everyday life with applications in medicine, industry, agriculture, and biotechnology. With the recent trends toward inquiry-based learning in undergraduate science teaching laboratory, we developed a crystals growth laboratory for first year students. While one objective is to learn how to grow and handle crystals, the laboratory is designed to foster the acquisition of basic scientific knowledge and hands on experience to develop critical laboratory skills. In this sense, it is targeted for students with diverse backgrounds and, in accord with the liberal arts curriculum at NYU Abu Dhabi readily includes non-science majors. The original inspiration for the lab came from the 1960 classic book "Crystals and Crystal Growing" by Holden and Singer. We have expanded on the emphasis there on inorganic salt crystals to require students to crystallize macromolecules as well, in a research driven environment. Similar to projects carried in more advanced courses, students write an outline of their project that is developed into a full proposal through a literature search stimulated by in class discussions and peer-review. Some of the learning goals include the ability to design and manage a research project, propose ideas and methods to explore the topic of interest, learn various techniques and equipment common in a science laboratory, the ability to analyze data, acquire best practices in lab safety, and most importantly develop their scientific writing skills. Following 4-5 weeks of crystal growing and characterization, students present their data at the end of the semester Crystal Growth Symposium first presenting a 5 minute flash poster-presentation followed by a poster session. The symposium is a collective effort to enhance the students' presentation and communication skills and to showcase and encouraging high quality of research. While still evolving, the laboratory has seen a variety of mainly student-initiated investigations not only exploring a variety of methods to grow crystals, but also in exploring the effect of magnetic field, vibration, temperature, or pH on crystal growth. We will present organizational details of the laboratory program and present examples of many posters that have been generated during four years of operating the laboratory.

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Liang, Yuan-Chang, i Wei-Cheng Zhao. "Crystal Growth and Design of Disk/Filament ZnO-Decorated 1D TiO2 Composite Ceramics for Photoexcited Device Applications". Nanomaterials 11, nr 3 (8.03.2021): 667. http://dx.doi.org/10.3390/nano11030667.

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Disk- and filament-like ZnO crystals were decorated on one-dimensional TiO2 nanostructures (TiO2–ZnO) through various integrated physical and chemical synthesis methods. The morphology of the ZnO crystals on TiO2 varied with the chemical synthesis method used. ZnO nanodisks decorated with TiO2 nanorods (TiO2–ZnO–C) were synthesized using the chemical bath deposition method, and ZnO filament-like crystals decorated with TiO2 nanorods (TiO2–ZnO–H) were synthesized through the hydrothermal method. Compared with the pristine TiO2 nanorods, the as-synthesized TiO2–ZnO composites exhibited enhanced photophysiochemical performance. Furthermore, because of their fast electron transportation and abundant surface active sites, the ZnO nanodisks in the TiO2–ZnO–C composite exhibited a higher photoactivity than those in the TiO2–ZnO–H composite. The morphology and crystal quality of the ZnO decoration layer were manipulated using different synthesis methods to realize disk- or filament-like ZnO-decorated TiO2 composites with various photoactive performance levels.

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Jeon, Hye Jun, Hyeonwook Park, Ganesh Koyyada, Salh Alhammadi i Jae Hak Jung. "Optimal Cooling System Design for Increasing the Crystal Growth Rate of Single-Crystal Silicon Ingots in the Czochralski Process Using the Crystal Growth Simulation". Processes 8, nr 9 (1.09.2020): 1077. http://dx.doi.org/10.3390/pr8091077.

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Here, we report a successfully modified Czochralski process system by introducing the cooling system and subsequent examination of the results using crystal growth simulation analysis. Two types of cooling system models have been designed, i.e., long type and double type cooling design (LTCD and DTCD) and their production quality of monocrystalline silicon ingot was compared with that of the basic type cooling design (BTCD) system. The designed cooling system improved the uniformity of the temperature gradient in the crystal and resulted in the significant decrease of the thermal stress. Moreover, the silicon monocrystalline ingot growth rate has been enhanced to 18% by using BTCD system. The detailed simulation results have been discussed in the manuscript. The present research demonstrates that the proposed cooling system would stand as a promising technique to be applied in CZ-Si crystal growth with a large size/high pulling rate.

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Yao, Xiaogang, Zhen Kong, Shengfu Liu, Yong Wang, Yongliang Shao, Yongzhong Wu i Xiaopeng Hao. "Comparative Studies of c- and m-Plane AlN Seeds Grown by Physical Vapor Transport". Materials 15, nr 24 (9.12.2022): 8791. http://dx.doi.org/10.3390/ma15248791.

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The ultra-wide bandgap semiconductor AlN has attracted a great deal of attention owing to its wide application potential in the field of electronics and optoelectronic devices. In this report, based on the mechanism of the physical vapor transport (PVT) growth of AlN crystal, the c- and m-plane AlN seed crystals were prepared simultaneously through special temperature field design. It is proved that AlN crystals with different orientations can be obtained at the same temperature field. The structure parameter of AlN crystal was obtained through the characteristic evaluations. In detail, XPS was used to analyze the chemical states and bonding states of the surface of seed crystals. The content of oxygen varied along with distinct orientations. Raman spectrum documented a small level of compressive stress on these crystal seeds. Tested results confirmed that the prepared AlN crystal seeds had high quality.

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Lu, Dazhi, Xiaoheng Li, Haohai Yu, Huaijin Zhang i Jiyang Wang. "Review of the Yb3+:ScBO3 Laser Crystal Growth, Characterization, and Laser Applications". Applied Sciences 11, nr 22 (17.11.2021): 10879. http://dx.doi.org/10.3390/app112210879.

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Passive Q-switching is an effective approach for generating pulsed lasers, owing to its compact and additional modulation-free design. However, to compare favorably with active Q-switching and multi-stage amplification, the output energy needs to be enhanced for practical applications. Kramers Ytterbium ion (Yb3+)-doped borate crystals, with their excellent energy storage capacity, have been proven to be high-potential laser gain mediums for achieving pulsed lasers with moderate and high output energy using passive Q-switching technology. In this study, the growth, characterization, and laser generation of one Yb3+-doped borate crystal, the Yb3+:ScBO3 crystal, are systematically reviewed. The continuous-wave and passive Q-switching laser characteristics are presented in detail, and the self-pulsations derived from intrinsic ground-state reabsorption are also demonstrated. The specific characteristics and experiments confirm the potential of the Yb3+:ScBO3 crystal for future pulsed laser applications with moderate or even high energy output.

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46

Nakamura, Hirohiko, Sachiko Takahashi, Koji Inaka i Hiroaki Tanaka. "Semi-empirical model to estimate ideal conditions for the growth of large protein crystals". Acta Crystallographica Section D Structural Biology 76, nr 12 (26.11.2020): 1174–83. http://dx.doi.org/10.1107/s205979832001445x.

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A large high-quality crystal is required to specify the positions of H atoms in neutron structural analysis. Consequently, several methods have been proposed for obtaining such large crystals, and theoretical considerations for growing them have been presented. However, further investigation is required to obtain a numerical model that can provide quantitative experimental conditions for obtaining a single large crystal. In the case of protein crystallization experiments, the amount of sample is often limited. Therefore, it is more realistic to make a rough estimation from a small number of experiments. This paper proposes a method of estimating the optimum experimental conditions for the growth of large protein crystals by performing a small number of experiments using a micro-batch method and reporting a numerical model based on nucleation theory and a linear approximation of the crystal-growth rate. Specifically, micro-batch experiments are performed to provide the empirical parameters for the model and to help to estimate the conditions for the growth of a crystal of a predetermined size using a certain sample concentration and volume. This method is offered as a step on the path towards efficiently and rationally producing large crystals that can be subjected to neutron diffraction without depending on luck or on performing many experiments. It is expected to contribute to drug design and the elucidation of protein molecular functions and mechanisms by obtaining positional information on H atoms in the protein molecule, which is an advantage of neutron diffraction.

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Wang, Lan, Guilin Liu, Xi Xi, Guofeng Yang, Lifa Hu, Bingjie Zhu, Yifeng He i in. "Annealing Engineering in the Growth of Perovskite Grains". Crystals 12, nr 7 (24.06.2022): 894. http://dx.doi.org/10.3390/cryst12070894.

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Perovskite solar cells (PSCs) are a promising and fast-growing type of photovoltaic cell due to their low cost and high conversion efficiency. The high efficiency of PSCs is closely related to the quality of the photosensitive layer, and the high-quality light absorbing layer depends on the growth condition of the crystals. In the formation of high-quality crystals, annealing is an indispensable and crucial part, which serves to evaporate the solvent and drive the crystallization of the film. Various annealing methods have different effects on the promotion of the film growth process owing to the way they work. Here, this review will present a discussion of the growth puzzles and quality of perovskite crystals under different driving forces, and then explain the relationship between the annealing driving force and crystal growth. We divided the main current annealing methods into physical and chemical annealing, which has never been summarized before. The main annealing methods currently reported for crystal growth are summarized to visualize the impact of annealing design strategies on photovoltaic performance, while the growth mechanisms of thin films under multiple annealing methods are also discussed. Finally, we suggest future perspectives and trends in the industrial fabrication of PSCs in the future. The review promises industrial manufacturing of annealed PSCs. The review is expected to facilitate the industrial fabrication of PSCs.

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Jeon, Hye Jun, Hyeonwook Park, Salh Alhammadi, Jae Hak Jung i Woo Kyoung Kim. "Optimal Magnetic Graphite Heater Design for Impurity Control in Single-Crystal Si Grower Using Crystal Growth Simulation". Processes 10, nr 1 (30.12.2021): 70. http://dx.doi.org/10.3390/pr10010070.

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In this paper, we report a successfully modified single-crystal Si growth furnace for impurity control. Four types of arbitrary magnetic heater (AMGH) systems with 3, 4, 5, and poly parts were designed in a coil shape and analyzed using crystal growth simulation. The concentration of oxygen impurities in single-crystal Si ingots was compared among the designed AMGHs and a normal graphite heater (NGH). The designed AMGHs were confirmed to be able to control turbulence and convection in a molten state, which created a vortex that influenced the oxygen direction near the melt–crystal interface. It was confirmed that replacing NGH with AMGHs resulted in a reduction in the average oxygen concentration at the Si melt–crystal interface by approximately 4.8%.

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Kuz’micheva, Galina, Irina Kaurova, Victor Rybakov i Vadim Podbel’skiy. "Crystallochemical Design of Huntite-Family Compounds". Crystals 9, nr 2 (15.02.2019): 100. http://dx.doi.org/10.3390/cryst9020100.

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Huntite-family nominally-pure and activated/co-activated LnM3(BO3)4 (Ln = La–Lu, Y; M = Al, Fe, Cr, Ga, Sc) compounds and their-based solid solutions are promising materials for lasers, nonlinear optics, spintronics, and photonics, which are characterized by multifunctional properties depending on a composition and crystal structure. The purpose of the work is to establish stability regions for the rare-earth orthoborates in crystallochemical coordinates (sizes of Ln and M ions) based on their real compositions and space symmetry depending on thermodynamic, kinetic, and crystallochemical factors. The use of diffraction structural techniques to study single crystals with a detailed analysis of diffraction patterns, refinement of crystallographic site occupancies (real composition), and determination of structure–composition correlations is the most efficient and effective option to achieve the purpose. This approach is applied and shown primarily for the rare-earth scandium borates having interesting structural features compared with the other orthoborates. Visualization of structures allowed to establish features of formation of phases with different compositions, to classify and systematize huntite-family compounds using crystallochemical concepts (structure and superstructure, ordering and disordering, isostructural and isotype compounds) and phenomena (isomorphism, morphotropism, polymorphism, polytypism). Particular attention is paid to methods and conditions for crystal growth, affecting a crystal real composition and symmetry. A critical analysis of literature data made it possible to formulate unsolved problems in materials science of rare-earth orthoborates, mainly scandium borates, which are distinguished by an ability to form internal and substitutional (Ln and Sc atoms), unlimited and limited solid solutions depending on the geometric factor.

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Chen, Q. S., H. Zhang, V. Prasad, C. M. Balkas i N. K. Yushin. "Modeling of Heat Transfer and Kinetics of Physical Vapor Transport Growth of Silicon Carbide Crystals". Journal of Heat Transfer 123, nr 6 (9.04.2001): 1098–109. http://dx.doi.org/10.1115/1.1409263.

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Wide-bandgap silicon carbide (SiC) substrates are needed for fabrication of electronic and optoelectronic devices and circuits that can function under high-temperature, high-power, high-frequency conditions. The bulk growth of SiC single crystal by physical vapor transport (PVT), modified Lely method involves sublimation of a SiC powder charge, mass transfer through an inert gas environment, and condensation on a seed. Temperature distribution in the growth system and growth rate profile on the crystal surface are critical to the quality and size of the grown SiC single crystal. Modeling of SiC growth is considered important for the design of efficient systems and reduction of defect density and micropipes in as-grown crystals. A comprehensive process model for SiC bulk growth has been developed that incorporates the calculations of radio frequency (RF) heating, heat and mass transfer and growth kinetics. The effects of current in the induction coil as well as that of coil position on thermal field and growth rate have been studied in detail. The growth rate has an Arrhenius-type dependence on deposition surface temperature and a linear dependence on the temperature gradient in the growth chamber.

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