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Published: 10 December 2022
Last updated: 28 January 2023

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1

Dufton, P. L., and A. E. Kingston. "SI II line ratios in the sun." Astrophysical Journal 289 (February 1985): 844. http://dx.doi.org/10.1086/162948.

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2

Djeniže, S., A. Srećković, and S. Bukvić. "On the line intensity ratios of prominent Si II, Si III, and Si IV multiplets." Spectrochimica Acta Part B: Atomic Spectroscopy 65, no. 1 (January 2010): 61–65. http://dx.doi.org/10.1016/j.sab.2009.11.004.

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3

Yoshida, Takashi, Hideyuki Umeda, and Ken’ichi Nomoto. "Si Isotopic Ratios in Supernovae for Presolar Grains." Astrophysical Journal 631, no. 2 (October 2005): 1039–50. http://dx.doi.org/10.1086/432654.

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4

Takechi, Kazushige, Mitsuru Nakata, Shinya Yamaguchi, Hiroshi Tanabe, and Setsuo Kaneko. "Amorphous In–Sn–Si–O Thin-Film Transistors Having Various Si Compositional Ratios." Japanese Journal of Applied Physics 49, no. 2 (February 22, 2010): 028002. http://dx.doi.org/10.1143/jjap.49.028002.

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5

Pradell, Trinitat, D. Crespo, Narcis Clavaguera, and Maria T. Clavaguera-Mora. "Nanocrystallisation in Finemet Alloys with Different Si/B Ratios." Materials Science Forum 307 (March 1999): 83–88. http://dx.doi.org/10.4028/www.scientific.net/msf.307.83.

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6

Pradell, Trinitat, D. Crespo, Narcis Clavaguera, and Maria T. Clavaguera-Mora. "Nanocrystallisation in Finemet Alloys with Different Si/B Ratios." Journal of Metastable and Nanocrystalline Materials 1 (March 1999): 83–88. http://dx.doi.org/10.4028/www.scientific.net/jmnm.1.83.

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7

Lugaro, Maria, Ernst Zinner, Roberto Gallino, and Sachiko Amari. "Si Isotopic Ratios in Mainstream Presolar SiC Grains Revisited." Astrophysical Journal 527, no. 1 (December 10, 1999): 369–94. http://dx.doi.org/10.1086/308078.

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8

Petrovic, Ivan, and Alexandra Navrotsky. "Thermochemistry of Na-faujasites with varying Si/Al ratios." Microporous Materials 9, no. 1-2 (March 1997): 1–12. http://dx.doi.org/10.1016/s0927-6513(96)00060-0.

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9

Kloetstra, K. R., H. W. Zandbergen, and H. van Bekkum. "MCM-41 type materials with low Si/Al ratios." Catalysis Letters 33, no. 1-2 (March 1995): 157–63. http://dx.doi.org/10.1007/bf00817055.

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10

Filiberto, J. "The Mars/Earth dichotomy in Mg/Si and Al/Si ratios: Is it real?" American Mineralogist 91, no. 2-3 (February 1, 2006): 471–74. http://dx.doi.org/10.2138/am.2006.2110.

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11

Jakobsson, Sigurdur. "Determination of Si/Al Ratios in Semicrystalline Aluminosilicates by FT-IR Spectroscopy." Applied Spectroscopy 56, no. 6 (June 2002): 797–99. http://dx.doi.org/10.1366/000370202760077559.

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Infrared spectra of synthetic, semicrystalline aluminosilicates in the region 500–1200 cm−1 show a dominant band due to Si–O stretching at 980–1030 cm−1 and two combined bands due to Si–O–Al bending at 600–700 cm−1. These bands can be used to determine quantitatively the Si/Al ratio of the aluminosilicates. A calibration curve has been obtained by integrating the intensities of the bands and relating them to Si/Al ratios of 10 aluminosilicate samples as measured with inductively coupled plasma (ICP) with Si/Al ratios ranging from 0.19 to 1.46.
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12

Piluso, Nicolò, Andrea Severino, Massimo Camarda, Ruggero Anzalone, Andrea Canino, Giuseppe Condorelli, Giuseppe Abbondanza, and Francesco La Via. "Raman Characterization of Doped 3C-SiC/Si for Different Silicon Substrates and C/Si Ratios." Materials Science Forum 645-648 (April 2010): 255–58. http://dx.doi.org/10.4028/www.scientific.net/msf.645-648.255.

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Raman microscopy has been used to study transport properties in hetero-epitaxial 3C-SiC/Si thin films. By an accurate analysis of the Longitudinal Optic phonon-plasmon coupled (LOPC) modes in n-type doped 3C-SiC films, free carrier density and mobility has been determined. A study of doped 3C-SiC reveals a strong relationship between the calculated free carrier density and both the C/Si ratio used during the epitaxial process and Silicon substrates orientation on which 3C-SiC thin films were grown (maintaining the N2 gas flow rate). The free carrier density obtained is in the range between 5x1016 cm-3 and 4x1018 cm-3. Epitaxial films grown on (111) Si substrates show a higher free carrier density and a lower dependence on C/Si ratios as compared to films grown on (100) Si substrates.
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13

Huang, W. J., W. J. Cai, R. T. Powell, S. E. Lohrenz, Y. Wang, L. Q. Jiang, and C. S. Hopkinson. "The stoichiometric ratio during biological removal of inorganic carbon and nutrient in the Mississippi River plume and adjacent continental shelf." Biogeosciences Discussions 9, no. 2 (February 6, 2012): 1557–85. http://dx.doi.org/10.5194/bgd-9-1557-2012.

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Abstract. The stoichiometric ratios of dissolved inorganic carbon (DIC) and nutrients during biological removal have been widely assumed to follow the Redfield ratios (especially the C/N ratio) in large river plume ecosystems. However, this assumption has not been systematically examined and documented because DIC and nutrients are rarely studied simultaneously in a river plume area, a region in which they can be affected by strong river-ocean mixing as well as intense biological activity. We examined stoichiometric ratios of DIC, total alkalinity (TA), and nutrients (NO3, PO43− and Si(OH)4) data during biological removal in the Mississippi River plume and adjacent continental shelf in June 2003 and August 2004 with biological removals defined as the difference between measured values and values predicted on the basis of conservative mixing determined using a multi-endmember mixing model. Despite complex physical and biogeochemical influences, relationships between DIC and nutrients were strongly dependent on salinity range and geographic location, and influenced by biological removal. Lower C/Si and N/Si ratios in one nearshore area were attributed to a potential silicate source induced by water exchange with coastal salt marshes. When net biological uptake was separated from river-ocean mixing and the impact of marshes and bays excluded, stoichiometric ratios of C/N/Si were similar to the Redfield ratios, thus supporting the applicability of the Redfield-type C/N/Si ratios as a principle in river-plume biogeochemical models.
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14

Lee, Kung Yen, Shin Yi Lee, and Chih Fang Huang. "Doping Concentration and Surface Morphology of 4H-SiC C-Face Epitaxial Growth." Materials Science Forum 645-648 (April 2010): 123–26. http://dx.doi.org/10.4028/www.scientific.net/msf.645-648.123.

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This research is focused on the influence of high C/Si ratios and low pressure on n-type doping concentration and surface defects of 4H-SiC C-face epilayers. N-type doping concentration decreases as C/Si ratio increases from 3.0 to 4.0 and pressure reduces from 100 mbar to 50 mbar; defect densities decrease as pressure increases at both C/Si ratios of 3.0 and 4.0. RMS roughness is about 0.21 nm for all C-face samples, independent of C/Si ratios of 3.0 and 4.0 and pressure from 50 mbar to 100 mbar. However, the influence of growth temperature on doping concentration and surface defects can not be clearly observed in this work.
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15

Mena, Elisa Delgado, Garik Israelian, Jonay I. González Hernández, Jade C. Bond, Nuno C. Santos, Stéphane Udry, and Michel Mayor. "Chemical clues on the formation of planetary systems." Proceedings of the International Astronomical Union 6, S276 (October 2010): 25–29. http://dx.doi.org/10.1017/s1743921311019880.

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AbstractTheoretical studies suggest that C/O and Mg/Si are the most important elemental ratios in determining the mineralogy of terrestrial planets. The C/O ratio controls the distribution of Si among carbide and oxide species, while Mg/Si gives information about the silicate mineralogy. We find mineralogical ratios quite different from those of the Sun, showing that there is a wide variety of planetary systems which are not similar to Solar System. Many of planetary host stars present a Mg/Si value lower than 1, so their planets will have a high Si content to form species such as MgSiO3. This type of composition can have important implications for planetary processes like plate tectonics, atmospheric composition or volcanism. Moreover, the information given by these ratios can guide us in the search of stars more probable to form terrestrial planets.
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16

Lee, Jae-Woo, and Bruce W. Carney. "[Si/Ti] elemental ratios in 9 old halo globular clusters." Proceedings of the International Astronomical Union 1, S228 (May 2005): 401–2. http://dx.doi.org/10.1017/s1743921305006071.

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17

Oehme, M., D. Hähnel, J. Werner, M. Kaschel, O. Kirfel, E. Kasper, and J. Schulze. "Si Esaki diodes with high peak to valley current ratios." Applied Physics Letters 95, no. 24 (December 14, 2009): 242109. http://dx.doi.org/10.1063/1.3274136.

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18

Alexander, Conel M. O’D, and Larry R. Nittler. "The Galactic Evolution of Si, Ti, and O Isotopic Ratios." Astrophysical Journal 519, no. 1 (July 1999): 222–35. http://dx.doi.org/10.1086/307340.

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19

Bezouhanova, C. P., Chr Dimitrov, V. Nenova, L. Dimitrov, and H. Lechert. "Cracking of paraffins on pentasils with different Si/Al ratios." Applied Catalysis 19, no. 1 (January 1985): 101–8. http://dx.doi.org/10.1016/s0166-9834(00)82673-1.

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20

Sharma, Pankaj, Moon Hee Han, and Churl-Hee Cho. "Synthesis of Zeolite Nanomolecular Sieves of Different Si/Al Ratios." Journal of Nanomaterials 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/912575.

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Nanosized zeolite molecular sieves of different Si/Al ratios have been prepared using microwave hydrothermal reactor (MHR) for their greater application in separation and catalytic science. The as-synthesized molecular sieves belong to four different type zeolite families: MFI (infinite and high silica), FAU (moderate silica), LTA (low silica and high alumina), and AFI (alumina rich and silica-free). The phase purity of molecular sieves has been assessed by X-ray diffraction (XRD) analysis and morphological evaluation done by electron microscopy. Broad XRD peaks reveal that each zeolite molecular sieve sample is composed of nanocrystallites. Scanning electron microscopic images feature the notion that the incorporation of aluminum to MFI zeolite synthesis results in morphological change. The crystals of pure silica MFI zeolite (silicalite-1) have hexagon lump/disk-like shape, whereas MFI zeolite particles with Si/Al molar ratios 250 and 100 have distorted hexagonal lump/disk and pseudo spherical shapes, respectively. Furthermore, phase pure zeolite nanocrystals of octahedron (FAU), cubic (LTA), and rod (AFI) shape have been synthesized. The average sizes of MFI, FAU, LTA, and AFI zeolite crystals are 250, 150, 50, and 3000 nm, respectively. Although the length of AFI zeolite rods is in micron scale, the thickness and width are of a few nanometers.
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21

Wahlberg, G., G. Wirmark, and N. Nordén. "SI (LI)-detector efficiencies characterized using x-ray intensity ratios." Ultramicroscopy 19, no. 4 (January 1986): 410–11. http://dx.doi.org/10.1016/0304-3991(86)90155-5.

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22

Keenan, F. P., A. E. Kingston, K. M. Aggarwal, and K. G. Widing. "Mg vii and Si ix line ratios in the sun." Solar Physics 103, no. 2 (February 1986): 225–30. http://dx.doi.org/10.1007/bf00147825.

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23

Hermanutz, Luise, David Innes, Andrew Denham, and Robert Whelan. "Very Low Fruit : Flower Ratios in Grevillea (Proteaceae) are Independent of Breeding System." Australian Journal of Botany 46, no. 4 (1998): 465. http://dx.doi.org/10.1071/bt97046.

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Members of the family Proteaceae have extremely low mature fruit : flower (FR : FL) ratios (range 0.001–0.163) compared with other temperate, hermaphroditic, woody perennials. Sutherland’s (1986) survey of FR : FL ratios indicated that compatibility was an important factor explaining levels of fruit set. The role of compatibility in regulating FR : FL ratios was tested in five closely related species of Grevillea (Proteaceae). Species-specific compatibility was compared using the self-compatibility index (SI = ratio of selfed fruit set to crossed fruit set) calculated at fruit initiation to minimise the confounding effect of other post-fertilisation fruit losses, such as inbreeding depression and pre-dispersal predation. Fruit : flower ratios at initiation ranged from 0.041–0.249, and at maturity 0.015–0.096. Grevillea species showed highly variable breeding systems: G. linearifolia was self-incompatible (SI = 0.003), G. sphacelata, G. mucronulata, and G. oleoides were partially self-compatible (SI = 0.07–0.28) and G. longifolia was self-compatible (SI = 0.61). Intrapopulation variability in the level of self-incompatibility was high in all species but G. linearifolia. The correlation between SI and FR: FL ratios was non-significant, indicating that compatibility has a minimal effect on fruit set in the Grevillea species studied, and that these data, together with other data on proteaceous species do not support trends observed in Sutherland’s survey. Low FR : FL ratios resulted from of a combination of pollen limitation, and high levels of flower and fruit predation.
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24

Huang, W. J., W. J. Cai, R. T. Powell, S. E. Lohrenz, Y. Wang, L. Q. Jiang, and C. S. Hopkinson. "The stoichiometry of inorganic carbon and nutrient removal in the Mississippi River plume and adjacent continental shelf." Biogeosciences 9, no. 7 (July 30, 2012): 2781–92. http://dx.doi.org/10.5194/bg-9-2781-2012.

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Abstract. The stoichiometry of dissolved inorganic carbon (DIC) and nutrients during biological uptake is widely assumed to follow the Redfield ratios (especially the C / N ratio) in large river plume ecosystems. However, this assumption has not been systematically examined and documented, because DIC and nutrients are rarely studied simultaneously in river plume areas and interpretation of ratios can be confounded by strong river–ocean mixing as well as intense biological activity. We examined stoichiometric ratios of DIC and nutrients (NO3-, PO43- and Si[OH]4) in the Mississippi River plume and adjacent continental shelf in June 2003 and August 2004 and calculated biological removal as the difference between observed concentrations and those predicted from conservative mixing, as determined from a multi-end-member mixing model and observed salinity and total alkalinity. Despite complex physical and biogeochemical influences, relationships between DIC and nutrients were strongly dependent on salinity range and geographic location, and influenced by biological removal. Lower C / Si and N / Si ratios in one nearshore area were likely due to localized input of high Si and low NO3- water from adjacent wetlands or preferential removal of nitrogen in the area. When net biological uptake was separated from river–ocean mixing and corrected for preferential N removal, the stoichiometric ratio of C / N / Si was similar to the Redfield ratio, thus supporting the applicability of the Redfield-type C / N / Si ratios in river-plume biogeochemical models.
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25

Yu, Yan Zhen, Juan Tan, and Yong Sun. "Study on the Reaction Process of Ploy-High-Ferric-Silicic Coagulant." Advanced Materials Research 156-157 (October 2010): 1074–77. http://dx.doi.org/10.4028/www.scientific.net/amr.156-157.1074.

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A new inorganic polymer coagulant，ploy-high-ferric-silicic coagulant with various Si/FeO42- ratios and salt-basicity, was prepared using the fly ash extract and potassium ferrate. The influence of both Si/FeO42- ratios and salt-basicity on the complexation process was explored with many analytical methods, such as transmission electron microscope (TEM), lased particle size analysis (LPSA) and infrared spectrum (IR). The results show that the ploy-high-ferric-silicic is a complexation compound, instead of a simple mixture of raw materials. The complexation process between Si and Fe may be different from various Si/FeO42- ratios and salt-basicity. The bonding can help revealing the high-ferric groups function in synthesis process. From analyzing the different ferrosilicon bonding modes, it can provide some theoretical basis to compound high-ferric coagulant.
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26

Hudec, Pavol, Agáta Smiešková, Zdenek Židek, Milan Zúbek, Petr Schneider, Milan Kočiřík, and Jana Kozánková. "Adsorption Properties of ZSM-5 Zeolites." Collection of Czechoslovak Chemical Communications 63, no. 2 (1998): 141–54. http://dx.doi.org/10.1135/cccc19980141.

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Adsorption properties determined by physical adsorption of nitrogen for a series of ZSM-5 zeolite samples with various Si/Al ratios and different crystal size were compared. In addition to the BET method, the t-plot method was used to determine the microporosity of samples. Very small crystals of ZSM-5 zeolites, generally below 1 μm, with Si/Al ratio between 14 and 21 exhibit adsorption isotherms typical for purely microporous solids. Samples with Si/Al ratios larger than (about) 95 show low-pressure steps and hysteresis loops and, depending on crystal morphology, also high-pressure hysteresis loops. The low-pressure steps were associated with steps on t-plots which showed two linear parts. Small increase of adsorption up to relative pressure 0.2 is characteristic for samples with Si/Al ratios between 25 and 50.
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27

Zou, Xuan, Jingyuan Zhou, Xianwen Ran, Yiting Wu, Ping Liu, Wenhui Tang, Pengwan Chen, and Haifu Wang. "Research on the Ignition Height and Reaction Flame Temperature of PTFE/Al/Si/CuO with Different Mass Ratios of PTFE/Si." Materials 14, no. 13 (June 22, 2021): 3464. http://dx.doi.org/10.3390/ma14133464.

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Recent studies have shown that the energy release capacity of Polytetrafluoroethylene (PTFE)/Al with Si, and CuO, respectively, is higher than that of PTFE/Al. PTFE/Al/Si/CuO reactive materials with four proportions of PTFE/Si were designed by the molding–sintering process to study the influence of different PTFE/Si mass ratios on energy release. A drop hammer was selected for igniting the specimens, and the high-speed camera and spectrometer systems were used to record the energy release process and the flame spectrum, respectively. The ignition height of the reactive material was obtained by fitting the relationship between the flame duration and the drop height. It was found that the ignition height of PTFE/Al/Si/CuO containing 20% PTFE/Si is 48.27 cm, which is the lowest compared to the ignition height of other Si/PTFE ratios of PTFE/Al/Si/CuO; the flame temperature was calculated from the flame spectrum. It was found that flame temperature changes little for the same reactive material at different drop heights. Compared with the flame temperature of PTFE/Al/Si/CuO with four mass ratios, it was found that the flame temperature of PTFE/Al/Si/CuO with 20% PTFE/Si is the highest, which is 2589 K. The results show that PTFE/Al/Si/CuO containing 20% PTFE/Si is easier to be ignited and has a stronger temperature destruction effect.
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28

Suárez-Andrés, L., G. Israelian, J. I. González Hernández, V. Zh Adibekyan, E. Delgado Mena, N. C. Santos, and S. G. Sousa. "C/O vs. Mg/Si ratios in solar type stars: The HARPS sample." Astronomy & Astrophysics 614 (June 2018): A84. http://dx.doi.org/10.1051/0004-6361/201730743.

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Context. Aims. We aim to present a detailed study of the magnesium-to-silicon and carbon-to-oxygen ratios (Mg/Si and C/O) and their importance in determining the mineralogy of planetary companions. Methods. Using 499 solar-like stars from the HARPS sample, we determined C/O and Mg/Si elemental abundance ratios to study the nature of the possible planets formed. We separated the planetary population in low-mass planets (<30 M⊙) and high-mass planets (>30 M⊙) to test for a possible relation with the mass. Results. We find a diversity of mineralogical ratios that reveal the different kinds of planetary systems that can be formed, most of them dissimilar to our solar system. The different values of the Mg/Si and C/O can determine different composition of planets formed. We found that 100% of our planetary sample present C/O < 0.8. 86% of stars with high-mass companions present 0.8 > C/O > 0.4, while 14% present C/O values lower than 0.4. Regarding Mg/Si, all stars with low-mass planetary companion showed values between one and two, while 85% of the high-mass companion sample does. The other 15% showed Mg/Si values below one. No stars with planets were found with Mg/Si > 2. Planet hosts with low-mass companions present C/O and Mg/Si similar to those found in the Sun, whereas stars with high-mass companions have lower C/O.
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29

Wang, Yong, and William J. Thomson. "Mullite formation from nonstoichiometric slow hydrolyzed single phase gels." Journal of Materials Research 10, no. 4 (April 1995): 912–17. http://dx.doi.org/10.1557/jmr.1995.0912.

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A comparative dynamic x-ray diffraction (DXRD) and differential thermal analysis (DTA) study was performed in the investigation of mullite and spinel formation from slowly hydrolyzed single phase gels with Al/Si ratios ranging from 1/1 to 14/1. Both metastable tetragonal mullite and spinel were observed to form at temperatures <1000 °C in the gels with Al/Si ratios <8/1 and mullite transformed to the orthorhombic structure at ∼1250 °C. However, at higher Al/Si ratios, spinel was the only crystalline phase detected at <1000 °C and orthorhombic mullite formed directly at temperatures >1250 °C. As the Al/Si ratio increases, both the tetragonal mullite and spinel formation temperatures decrease while the orthorhombic mullite formation temperature increases. Based on the Al/Si composition where the formation extents of tetragonal mullite and spinel were maximum, their compositions are estimated to be 2Al2O3 · SiO2 and 6A12O3 · SiO2, respectively.
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30

Daigo, Yoshiaki, Yuya Takada, Keisuke Kurashima, Toru Watanabe, Akio Ishiguro, Shigeaki Ishii, Yoshikazu Moriyama, and Ichiro Mizushima. "Influence of residual dopants to net doping concentration in N-type 4H-SiC films grown using high-speed wafer rotation vertical CVD method." Japanese Journal of Applied Physics 61, SC (February 16, 2022): SC1041. http://dx.doi.org/10.35848/1347-4065/ac4c08.

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Abstract In this study, the influence of residual dopants on the net doping concentration in n-type 4H-SiC epitaxial films grown at different N2 flow rates and C/Si ratios were investigated. By reducing the N2 flow rate, the influence of the residual donors on the net doping concentration was observed to become dominant for the films grown at low C/Si ratios and that of the residual acceptors on the net doping concentration becomes dominant for the films grown at high C/Si ratios. For the films grown at the middle C/Si ratio, an apparent proportional relation due to the compensation balance between the residual and intentional donors and the residual acceptors was observed in the N2 flow rate dependence of the net doping concentration. Furthermore, the decay curve of the net doping concentration observed in the C/Si ratio dependence is affected by the compensation balance between the intentional dopant concentration and the residual dopant concentration.
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31

Choudhary, T. V., A. Kinage, S. Banerjee, and V. R. Choudhary. "Influence of Si/Ga and Si/Al ratios on propane aromatization over highly active H-GaAlMFI." Catalysis Communications 7, no. 3 (March 2006): 166–69. http://dx.doi.org/10.1016/j.catcom.2005.10.006.

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32

Jonathan, Carabin, Bouhamama Amine, Mandache Ana Maria, Basle Alexandre, Marie Edouard, Faure-Conter Cécile, Leblond Pierre, Frappaz Didier, Lardy-Cleaud Audrey, and Pilleul Frank. "Gadolinium Brain Deposition in the globus pallidus and dentate nucleus after serial administrations of a macrocyclic gadolinium-based contrast agent in oncologic pediatric patients." Imaging Journal of Clinical and Medical Sciences 9, no. 1 (September 30, 2022): 018–25. http://dx.doi.org/10.17352/2455-8702.000138.

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Introduction: Gadolinium deposition in the human brain, especially in the Globus Pallidus (GP) and the Dentate Nucleus (DN) has been reported after the administration of linear Gadolinium-Based Contrast Agents (GBCAs). This study aims to determine whether repeated injections of macrocyclic GBCA are associated with an increased Signal Intensity (SI) on T1-weighted sequences in the Globus Pallidus (GP) and Dentate Nucleus (DN) in oncologic pediatric patients. Materials and methods: This retrospective monocentric cohort study included consecutive children with at least two MRIs performed after administration of macrocyclic GBCAs. The SI measurements were determined on unenhanced T1-weighted images by drawing a circular region of interest (ROI) within GP and Thalamus (TH) and DN, Pons (P), at baseline, and at last MRI. SI ratios and the differences in ratios (GP/TH) and (DN/P) between the first and last MRI calculated. Results: Out of 413 consecutive children attending Leon Berard cancer center, 50 patients were included, and data analysis showed significantly increased GP/TH SI ratios between the first and the last MRI (p =0.0305). The DN/P SI ratios did not significantly differ between the first and the last MRI (p=0.2668). Conclusion: This study showed an increased SI in GP after several intravenous administrations of macrocyclic GBCAs but no increased SI was identified in the DN. Although no clinical adverse effects have been reported so far, the gadolinium deposits in the brain should be carefully monitored, especially in children who still undergo neurodevelopment.
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33

Koiso, Takao, Masaaki Yamamoto, Shinya Watanabe, and Bierta E. Barfod. "Signal intensity increases in dentate nucleus/globus pallidus/pulvinar on unenhanced T1WI MR images after multiple examinations with gadodiamide." Neuroradiology Journal 32, no. 3 (March 29, 2019): 215–24. http://dx.doi.org/10.1177/1971400919839646.

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Background and purpose Elevated signal intensity (SI) in the dentate nucleus (DN), globus pallidus (GP) and pulvinar (PUL) was reportedly observed on unenhanced T1-weighted (T1WI) magnetic resonance (MR) images in patients receiving multiple enhanced MR examinations. We aimed to clarify whether this phenomenon influences the long-term neurological status of patients. Materials and methods We studied 196 radiosurgically treated patients undergoing ≥10 MR examinations using a single dose of gadodiamide and the same 1.5 Tesla MR unit. SI ratios were calculated by referencing the brainstem (BS) for the DN and the thalamus (TH) for the GP and PUL. We compared the SI ratios at the first, fifth, and 10th, and at the most recent examinations. The neurological symptoms of all 196 patients were assessed at each MR examination by one of the authors (MY). Results The DN/BS and GP/TH SI ratios were significantly increased at the fifth examination ( p < .0001, p = 0.0094) and, thereafter, gradually increased. Although the PUL/TH SI ratio was not significantly increased at the fifth examination ( p = 0.2515), a significant increase was noted at the 10th examination ( p < .0001). There were no significant predictive factors for DN/BS SI increases. Younger age, no brain metastasis, and normal estimated glomerular filtration rate were related to GP/TH SI ratio increases ( p = 0.0308, p = 0.0001, p = 0.0306). Higher age and total bilirubin level were related to an increased PUL/TH SI ratio ( p = 0.0276, p = 0.0097). No patients experienced gadodiamide-related health problems. Conclusions Although the SI ratios rose as numbers of gadodiamide administrations increased, no adverse health effects have developed to date.
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Wang, Hongguang, Hao Wu, Zhiqiang Xing, Rui Wang, and Shoushuai Dai. "The Effect of Various Si/Al, Na/Al Molar Ratios and Free Water on Micromorphology and Macro-Strength of Metakaolin-Based Geopolymer." Materials 14, no. 14 (July 9, 2021): 3845. http://dx.doi.org/10.3390/ma14143845.

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The current work aimed to explore the effect of Na/Al ratios of 0.43, 0.53, 0.63, 0.73, 0.83, and 0.93, using NaOH to alter the molar ratio, on the mechanical properties of a geopolymer material, with fixing of the Si/Al molar ratio. While fixing the Na/Al molar ratio, alteration of the Si/Al ratios to 1.7, 1.75, 1.8, 1.85, 1.9, 1.95 was used, with silica fume and sodium silicate as a silica corrector. The influence on the micromorphology and macro-strength of samples was characterized through SEM, EDS, and compressive strength characterization methods. The results show that Si/Al and Na/Al molar ratios play a significant role in the microstructure and mechanical behavior of MK-based geopolymers, and revealed that the optimal molar Si/Al and Na/Al ratios for attaining maximum mechanical strength in geopolymers are 1.9 and 0.73, respectively. Under various Si/Al ratios, the macro-strength of the geopolymer mainly relies on the formation of NASH gel, rather than zeolites or silicate derivatives. The appropriate Na/Al molar ratio can contribute to the geopolymerization, but a ultra-high Na/Al molar ratio caused a high alkali state that destroyed the microstructure of the geopolymers. Regardless of the amount of water contained in the initial geopolymer raw material, the water content of Si/Al = 1.65 and Si/Al = 1.75 after curing for 10 days was almost the same, and the bound water content of the final geopolymer was maintained at about 15%. Structural water exists in geological polymer gels in the form of a chemical structure. It has effects on the structural performance strength, while free water affects the volume stability of the geological polymer. Overall, the current work provides a perspective on the elemental composition analysis, combined with the molecular structure and micromorphology, to explore the mechanical performance of geopolymers.
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35

Mei, Weiping, Yu Umezawa, Xin Wan, Jinghan Yuan, and Chiyuki Sassa. "Feeding habits estimated from weight-related isotope variations of mesopelagic fish larvae in the Kuroshio waters of the northeastern East China Sea." ICES Journal of Marine Science 76, no. 3 (March 13, 2018): 639–48. http://dx.doi.org/10.1093/icesjms/fsy016.

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Abstract Bulk carbon and nitrogen stable isotope (SI) ratios (δ13C and δ15N) were analysed to investigate the feeding habits of six taxa of mesopelagic fish larvae inhabiting the Kuroshio waters of the northeastern East China Sea. Large variation in tissue SI during early larval periods suggested maternal effects from parent fishes, and non-selective feeding on a variety of plankton species due to poor swimming ability. The similarity between SI ratios measured in larval tissues and those estimated for eggs of an “income breeder” in the spawning area support an “income breeder” strategy in Diaphus slender type and Vinciguerria nimbaria, while Lipolagus ochotensis seemed to show “capital breeder”-like characteristics. SI ratios of the fish larvae studied became relatively constant at species-specific body dry-weights (0.5–1.0 mg), probably due to the commencement of selective feeding, meaning SI ratios during late larval periods could be used for trophic position analysis. There was great overlap (44.6–76.5%) in trophic niche among the larval fishes within the same taxonomic family of Myctophidae. Even if principal diet components cannot be identified with gut contents analyses, diet information from other fish species occupying a similar isotopic niche can thus improve our understanding of the diets of larval fishes.
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36

Huang, Qiu Ying, Wei Liu, Wen Hao Ye, and Xiu Cheng Zheng. "Preparation and Characterization of Ti-SBA-15 Mesoporous Materials with Varying Si/Ti Molar Ratios." Advanced Materials Research 482-484 (February 2012): 985–88. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.985.

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Ti-SBA-15 mesoporous materials with different Si/Ti molar ratios were synthesized via a hydrothermal process and characterized by using various techniques. The effect of Si/Ti molar ratios in the gels on the structure and catalytic efficiency in epoxidation of cyclohexene was discussed in details. The results showed that all the Ti-SBA-15 materials retained SBA-15 mesoporous structure and exhibited good catalytic activity. Furthermore,the sample prepared with Si/Ti =50 exhibited the best catalytic performance under the reaction conditions.
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37

Nalbant, Asli, Timur Dogu, and Suna Balci. "Ni and Cu Incorporated Mesoporous Nanocomposite Catalytic Materials." Journal of Nanoscience and Nanotechnology 8, no. 2 (February 1, 2008): 549–56. http://dx.doi.org/10.1166/jnn.2008.c154.

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Nickel and copper incorporated MCM-41-like mesoporous nanocomposite materials prepared by the direct hydrothermal synthesis and the impregnation procedures showed highly attractive pore structure and surface area results for catalytic applications. The XRD patterns showed that characteristic MCM-41 structure was preserved for the materials synthesized following an impregnation procedure before the calcination step. The surface area of the Cu impregnated material with a quite high Cu/Si atomic ratio (0.19) was 631 m2/g. Very narrow pore size distributions with an average pore diameter of about 2.7 nm were obtained as a result of plugging of some of the smaller pores by Cu nanoballs. For lower metal to Si ratios (for instance for Ni/Si = 0.06) much higher surface area values (1130 m2/g) were obtained. In the case of nanocomposite materials synthesized by the direct hydrothermal route, MCM-41 structure was not destroyed for samples containing metal to Si atomic ratios as high as 0.12. In the case of materials containing Cu/Si and Ni/Si ratios over 0.2 wider pore size distributions and some decrease of surface area were observed.
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38

Chen, Nan Chun, Wei Wang, Ai Ping Deng, Han Mei Ao, and Quan Hong Li. "Effects of Si/Al Molar Ratio on Morphology of Mullite Nanocomposite Synthesized from Kaolin." Materials Science Forum 682 (March 2011): 55–59. http://dx.doi.org/10.4028/www.scientific.net/msf.682.55.

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Mullite nanocomposite was synthesized using kaolin with different Si/Al molar ratios in the range of 1.1- 4.31. The synthesized samples were analyzed and characterized using XRD and SEM techniques and effects of Si/Al molar ratio on mullite nanocrystal morphology have been investigated. SEM results showed that the mullite nanocomposite synthesized from kaolin with different Si/Al molar ratios had different morphologies and distribution patterns of particle size. It was found that the mullite nanocrystals with relatively homogenous grain-size distribution, low aspect ratio, and little agglomeration were produced from the precursors made from kaolin with a Si/Al ratio of 1.1-2.33 at calcination temperature of 1100-1250 oC.
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39

Grangeon, Sylvain, Francis Claret, Cédric Roosz, Tsutomu Sato, Stéphane Gaboreau, and Yannick Linard. "Structure of nanocrystalline calcium silicate hydrates: insights from X-ray diffraction, synchrotron X-ray absorption and nuclear magnetic resonance." Journal of Applied Crystallography 49, no. 3 (April 12, 2016): 771–83. http://dx.doi.org/10.1107/s1600576716003885.

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The structure of nanocrystalline calcium silicate hydrates (C–S–H) having Ca/Si ratios ranging between 0.57 ± 0.05 and 1.47 ± 0.04 was studied using an electron probe micro-analyser, powder X-ray diffraction,29Si magic angle spinning NMR, and Fourier-transform infrared and synchrotron X-ray absorption spectroscopies. All samples can be described as nanocrystalline and defective tobermorite. At low Ca/Si ratio, the Si chains are defect free and the SiQ3andQ2environments account, respectively, for up to 40.2 ± 1.5% and 55.6 ± 3.0% of the total Si, with part of theQ3Si being attributable to remnants of the synthesis reactant. As the Ca/Si ratio increases up to 0.87 ± 0.02, the SiQ3environment decreases down to 0 and is preferentially replaced by theQ2environment, which reaches 87.9 ± 2.0%. At higher ratios,Q2decreases down to 32.0 ± 7.6% for Ca/Si = 1.38 ± 0.03 and is replaced by theQ1environment, which peaks at 68.1 ± 3.8%. The combination of X-ray diffraction and NMR allowed capturing the depolymerization of Si chains as well as a two-step variation in the layer-to-layer distance. This latter first increases from ∼11.3 Å (for samples having a Ca/Si ratio <∼0.6) up to 12.25 Å at Ca/Si = 0.87 ± 0.02, probably as a result of a weaker layer-to-layer connectivity, and then decreases down to 11 Å when the Ca/Si ratio reaches 1.38 ± 0.03. The decrease in layer-to-layer distance results from the incorporation of interlayer Ca that may form a Ca(OH)2-like structure, nanocrystalline and intermixed with C–S–H layers, at high Ca/Si ratios.
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40

Abd El-Aaty, Heba R., Osama Tobail, Madiha A. Shoeib, and Iman El-Mahallawi. "Effect of Gas Dilution Ratios and Substrate Temperature on the Structural Transition of a-Si/μc-Si Thin-Film Solar Cell Using PECVD." Key Engineering Materials 786 (October 2018): 373–83. http://dx.doi.org/10.4028/www.scientific.net/kem.786.373.

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Thin films of mixed amorphous/ microcrystalline-phases have been researched during the last decade, for manufacturing silicon solar cells. In this work the Plasma Enhanced Chemical Vapor Deposition PECVD process parameters; namely dilution ratios and substrate temperature, were controlled to build i-layer at low dilution ratios with moderate substrate temperatures. In this work an intrinsic layer was deposited on Indium Tin Oxide ITO glass by PECVD technique, with different dilution ratios of silane in hydrogen to study the transition from amorphous to microcrystalline phase. The Si:H thin film was evaluated by field emission scanning electron microscopy, x-ray diffraction and atomic force microscopy. The structural transition between a-Si:H to μc-Si:H achieved at dilution ratio 13.3 and substrate temperature 250°C with surface roughness 22.5 nm.
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41

Cheng, Chih-Hsien, Jung-Hung Chang, Chih-I. Wu, and Gong-Ru Lin. "Semi-transparent silicon-rich silicon carbide photovoltaic solar cells." RSC Advances 5, no. 46 (2015): 36262–69. http://dx.doi.org/10.1039/c4ra16998k.

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Si-rich SixC1−x films grown at different RSiC fluence ratios were applied as an i-SixC1−x absorbing layer in all Si-rich SixC1−x-based PVSCs.
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42

Andarini, Novita, Tanti Haryati, and Zuhrotul Lutfia. "Synthesis of Zeolite A From Coal Fly Ash with Variation of Si/Al Molar Ratio." Jurnal ILMU DASAR 19, no. 2 (July 30, 2018): 105. http://dx.doi.org/10.19184/jid.v19i2.5910.

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Fly ash containing 30-36% silica and 14,52-23,78% alumina can be potentially as raw material for synthetic zeolite such as zeolite A. Zeolite A is an aluminosilicate mineral which is rich in alumina so that this zeolite has a good cation exchange capability. Zeolite A has been synthesized by hydrothermal treatment after NaOH fusion. Fly ash has been fused with NaOH at 550 0C for 40 minutes and hydrothermally treated at 1000C for 5 hours. The hydrothermal treatment was conducted in some various Si/Al molar ratios from 0.90; 1.00.; 1.05; to 1.24. The zeolite A was then analyzed using XRD and XRF. The best zeolite A based on XRD result is zeolite with Si/Al molar ratio of 1.1 with crystallinity of 96,80%. The x-ray fluorescence result showed that the Si/Al molar ratios of the four zeolite samples were close to of Si/Al molar ratios of 1, 1.1, 1.21.3 respectively.Keywords: Fly ash, Zeolite A, Hydrothermal Fusion
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43

Hanson, A. L., K. W. Jones, and D. R. Corbin. "Determination of Si/Al ratios in zeolites by proton inelastic scattering." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 9, no. 3 (June 1985): 301–5. http://dx.doi.org/10.1016/0168-583x(85)90754-2.

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44

Dwivedi, B. N. "Forbidden line ratios from Si viii and S x coronal ions." Solar Physics 131, no. 1 (January 1991): 49–52. http://dx.doi.org/10.1007/bf00151743.

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45

McCann, S. M., and F. P. Keenan. "Theoretical emission line ratios for Si XIII compared to solar observations." Solar Physics 112, no. 1 (1987): 83–88. http://dx.doi.org/10.1007/bf00148489.

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46

LIU, Zhong-Liang. "Effect of Different Si/C flux Ratios on the Growth of SiC on Si (111) by SSMBE." Journal of Inorganic Materials 23, no. 3 (August 4, 2008): 549–52. http://dx.doi.org/10.3724/sp.j.1077.2008.00549.

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47

García-Giménez, Rosario, Moisés Frias, Raquel Vigil de la Villa, and Sagrario Martínez-Ramírez. "Ca/Si and Si/Al Ratios of Metakaolinite-Based Wastes: Their Influence on Mineralogy and Mechanical Strengths." Applied Sciences 8, no. 4 (March 22, 2018): 480. http://dx.doi.org/10.3390/app8040480.

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48

Xu, Xuexuan, Zhao Yang, Yulong Ye, Guangxu Wang, and Xiaolong He. "Effects of various Mg/Si ratios on microstructure and performance property of Al-Mg-Si alloy cables." Materials Characterization 119 (September 2016): 114–19. http://dx.doi.org/10.1016/j.matchar.2016.07.011.

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49

Chung, C. K., and T. S. Chen. "Effect of Si/Ta and nitrogen ratios on the thermal stability of Ta–Si–N thin films." Microelectronic Engineering 87, no. 2 (February 2010): 129–34. http://dx.doi.org/10.1016/j.mee.2009.06.026.

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50

Söğüt, Ö., E. Büyükkasap, and A. Küçükönder. "Measurement of Lα/Lι X-ray intensity ratios." Canadian Journal of Physics 83, no. 9 (September 1, 2005): 951–55. http://dx.doi.org/10.1139/p05-045.

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Lα/Lι X-ray intensity ratios of La2O3, CeO2, Sm, Eu, Ho, Er, YbO2, Hf, Ta, W, Re, Pt, Au, HgO, Tl, Pb, Bi, ThO2, and U have been measured using the 59.5 keV incident photon energy. The LX-rays emitted from the samples were counted using a Si(Li) detector with a resolution 155 eV at 5.96 keV. PACS No.: 32.30.Rj
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