Higher Crystallization Temperature Research Articles

Electrical and Optical Characteristics of WOx, ZrHfO, and Tri-Layer WOx Embedded ZrHfO High-k Based SSI-LEDs

The solid state incandescent light emission device (SSI-LED), which can emit the broadband warm white light, is made from the high-k MOS capacitor after the dielectric breakdown [1-4]. Electrical properties of the capacitor, such as interface defect density (Dit ), oxide trapped charge density (Qot ), equivalent oxide thickness (EOT), and leakage current density (Jleakage ) are important to the dielectric breakdown process and eventually the optical properties of the emitted light. Since the zirconium hafnium oxide (ZrHfO) high-k material has superb gate dielectric properties, e.g., high crystallization temperature, low interface state density, oxide trapped charges, and high effective k value, it has been used as the gate dielectric layer of the MOS capacitor [5,6]. On the other hand, the WOx dielectric-based MOS capacitor and SSI-LED has been studied. The latter emitted light with relative high intensity due to the high emissivity coefficient of the W component [7]. However, the capacitor has a high leakage current which can be a reliability concern. In this paper, three types of MOS capacitors, i.e., with gate dielectrics made of ZrHfO, WOx, and ZrHfO/WOx/ZrHfO/WOx/ ZrHfO/WOx/ZrHfO, separately, have been fabricated into SSI-LEDs and studied for electrical and optical properties.MOS capacitors were prepared on a DHF pre-cleaned p-type <100> silicon (1015 cm-3) wafer. For the ZrHfO capacitor, the gate dielectric layer was sputter-deposited from the Zr/Hf (12/88 wt%) target in Ar/O2 (100:100 sccm) at 5 mTorr and 60 W for 12 min. The WOx layer was sputter-deposited from the W target (99.999 %) in Ar/O2 (40:100 sccm) at 5 mTorr and 60 W for 12 min. For the WOx embedded capacitor, the ZrHfO (2 min)/WOx (2 min)/ZrHfO (2 min)/WOx (2 min)/ ZrHfO (2 min)/WOx (2 min)/ZrHfO (2 min) stack was deposited in one pump down under the same conditions as each individual layer. The post-deposition annealing (PDA) was conducted at 900 ̊C under the O2 atmosphere for 5 min in furnace. An 80 nm thick ITO was sputter deposited and wet etched into round gate electrodes using an aqua regia solution. Then, the backside of the wafer was deposited with an aluminum thin film and annealed at 400 ̊C under H2/N2 (10/90) for 5 min. The dielectric breakdown voltage of the capacitor was determined from the current density-gate voltage (J-V) curve. The light emission characteristics the SSI-LED were measured from an optical emission spectrometer (OES, StellarNet).Electrical characteristics of the capacitors before and after the dielectric breakdown were discussed with respect to the gate dielectric material properties. Figure 1 shows the emission spectra of the 3 SSI-LEDs. They all emit broad band light in the range of UV to near IR. They are similar to the visible wavelength region of the solar light. The peak lengths λpeak’s of the ZrHfO, WOx, and WOx embedded devices are 638 nm, 687.15 nm, and 663 nm, respectively. The WOx SSI-LED has the highest emission intensity. It was reported that the emissivities of the pure (99.99 %) tungsten and the hafnium-3 wt% zirconium materials were 0.434 [8] and 0.30 [9] at 2000 K, respectively. Therefore, the inclusion of W component in conductive path may increase the light emission intensity of SSI-LED. According to the emission spectra, the CIE chromaticity chart has been prepared. The color correlation temperatures (CCT’s) and color rendering indices (CRI’s) were calculated. Y. Kuo, ECS Trans., 69, 23-29 (2015).C.-C. Lin and Y. Kuo, ECS J. Solid State Sci. Technol., 3, Q182 (2014).C.-C. Lin and Y. Kuo, J. Vac. Sci. Technol. B, 32, 011208 (2014).Y. Kuo and C.-C. Lin, Appl. Phys. Lett., 102, 031117 (2013).T.-C. Chang, F.-Y. Jian, S.-C. Chen and Y.-T. Tsai, Materials today, 14, 608-615 (2011).G. E. Moore, Cramming more components onto integrated circuits, McGraw-Hill New York, NY, USA (1965).M. Lorenz, H. von Wenckstern and M. Grundmann, Adv. Mater., 23, 5383-5386 (2011).R. D. Larrabee, JOSA, 49, 619-625 (1959).P.-F. Paradis, T. Ishikawa and S. Yoda, Int. J. Thermophys., 24, 239-258 (2003). Figure 1

Emerging Fluorite‐ and Wurtzite‐Type Ferroelectrics: From (Hf,Zr)O2 to AlN and Related Materials

Emerging Fluorite‐ and Wurtzite‐Type Ferroelectrics: From (Hf,Zr)O₂ to AlN and Related Materials

Thermal and mechanical properties of poly(L-lactic acid) nucleated with N,N’-bis(phenyl) 1,4-naphthalenedicarboxylic acid dihydrazide

The modified poly(L-lactic acid) (PLLA) with different contents (0.5−3 wt %) of N,N’-bis(phenyl) 1,4-naphthalenedicarboxylic acid dihydrazide (NAPH) were prepared to evaluate effects of NAPH on melt-crystallization behavior (DSC), thermal degradation (TGA) and mechanical properties of PLLA. The melt-crystallization results demonstrated that NAPH as a heterogeneous organic nucleating agent enhanced crystallization ability of PLLA in cooling, and PLLA/1%NAPH had the best crystallization ability because of the highest onset crystallization temperature and the sharpest melt-crystallization peak. However, melt-crystallization behavior also depended on the cooling rate and final melting temperature, overall, a relative slow cooling rate and low final melting temperature were beneficial for crystallization of PLLA. The cold-crystallization results indicated that NAPH had an inhibition for cold-crystallization process of PLLA, and the cold-crystallization peak shifted towards lower temperature and became wider with an increase of NAPH concentration. The different melting behaviors ofPLLA/NAPH after melt-crystallization and isothermal-crystallization efficiently reflected the accelerating role of NAPH for PLLA crystallization; the double melting peaks formed in heating were thought to result from melting-recrystallization, as well as that a higher crystallization temperature could cause melting peak to appear in higher temperature regions and possess larger melting enthalpy. A comparative analysis on thermal degradation in air illustrated that the addition of NAPH accelerated decomposition of PLLA, but a decrease of onset decomposition temperature was inhibited by the probable interaction of PLLA with NAPH. Moreover, the tensile test showed that NAPH decreased tensile modulus and elongation at break of PLLA, whereas PLLA with low concentration of NAPH had higher tensile strength than pure PLLA.

Hypogene kaolin deposits from felsic intrusive rocks (Peninsular Malaysia) with special reference to rare earth elements and stable isotopes geochemistry

Clay fractions of the hypogene kaolin deposits from Ipoh granite and Jerai pegmatite are composed of kaolinite, while the greenish kaolin horizon of Ipoh area comprises of illite and kaolinite. Al2O3 and SiO2 are the main constituents in the studied kaolins with very low concentrations of other oxides. K2O occurs in relatively high contents in the illite-rich kaolin that formed by hydrothermal alteration of biotite-granite of the greenish kaolin horizon of Ipoh area. The higher contents of Ba, Cr, Cs, Ga, Rb, Sc, and Sn in the illite-rich horizon are inherited from its source rock. The relative enrichment of light rare earth elements (LREE) over heavy rare earth elements (HREE) as indicated from the high (La/Yb)n ratios and positive correlations between ΣREE and P2O5 in the studied kaolins suggest the occurrence of REE as authigenic florencite, churchite and/or rhabdophane and, therefore, reflect the kaolinitization process rather than the parent rocks. δH and δO values are similar in both Ipoh and Jerai kaolins with dH values range from −84 to −99‰ and positive δO values varying between 0.95 and 5.47%. H- and O-isotopes data fall close to the left side of the kaolinite line in equilibrium with meteoric water at temperatures of > 100 °C. The pronounced negative Eu anomalies, absence of positive Ce anomaly and high crystallization temperature (94–113 °C) indicate the hydrothermal (hypogene) origin of the studied kaolins as a result of the Triassic post-magmatic hydrothermal activities in Peninsular Malaysia. Mineralogical and geochemical variations among the studied deposits although they formed by the same kaolinitization process, suggest a significant role of parent rocks in their compositions.

Do Olivine Crystallization Temperatures Faithfully Record Mantle Temperature Variability?

AbstractCrystallization temperatures of primitive olivine crystals have been widely used as both a proxy for, or an intermediate step in calculating, mantle temperatures. The olivine‐spinel aluminum‐exchange thermometer has been applied to samples from mid‐ocean ridges and large igneous provinces, yielding considerable variability in olivine crystallization temperatures. We supplement the existing data with new crystallization temperature estimates for Hawaii, between 1282 ± 21 and 1375 ± 19°C. Magmatic temperatures may be linked to mantle temperatures if the thermal changes during melting can be quantified. The magnitude of this temperature change depends on melt fraction, itself controlled by mantle temperature, mantle composition and lithosphere thickness. Both mantle composition and lithosphere thickness vary spatially and temporally, with systematic differences between mid‐ocean ridges, ocean islands and large igneous provinces. For crystallization temperatures to provide robust evidence of mantle temperature variability, the controls of lithosphere thickness and mantle lithology on crystallization temperature must be isolated. We develop a multi‐lithology melting model for predicting crystallization temperatures of magmas in both intra‐plate volcanic provinces and mid‐ocean ridges. We find that the high crystallization temperatures seen at mantle plume localities do require high mantle temperatures. In the absence of further constraints on mantle lithology or melt productivity, we cannot robustly infer variable plume temperatures between ocean‐islands and large igneous provinces from crystallization temperatures alone; for example, the extremely high crystallization temperatures obtained for the Tortugal Phanerozoic komatiite could derive from mantle of comparable temperature to modern‐day Hawaii. This work demonstrates the limit of petrological thermometers when other geodynamic parameters are poorly known.

Facile synthesis of bamboo-like Ba0.5Sr0.5Co0.8Fe0.2O3-δ@carbon nanofibers as freestanding cathode for highly stable Li-O2 batteries

A highly performance binder-free and freestanding cathode for Li-O2 battery (LOB) receives much attention to solve the major obstacles including sluggish oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) kinetics, unstable cathode, and irrational architecture design. Herein, we develop an effectively electrospinning to embed the oxygen vacancy-containing Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) particles into carbon nanofibers (BSCF@C nanofibers) towards the self-assembly cathode with high ORR and OER performance. Predictably, the BSCF@C nanofibers successfully prevent the BSCF particles from aggregation, facilitate O2 adsorption and diffusion, enhance the electron transfer, accelerate the Li2O2 nucleation/decomposition, and enhance the stability of cathode. Different from the conventional cathode, the LOBs with the BSCF@C nanofibers cathode perform an outstanding electrochemical performance, which providing a high discharge specific capacity of 11976 mAh g−1 and ultralong cycling stability of 98 times at the current density of 400 mA g−1. Notably, this work opens up an opportunity for the perovskite oxides with high crystallization temperature for high-performance energy storage systems at ambient temperature.

Mineralogical and geochemical investigation of megaspherulites from Argentina, Germany, and the USA

Textures and whole-rock chemistry, as well as mineral composition, were analyzed in megaspherulites (high-temperature crystallization domains [HTCDs]) that formed in different geographical and geotectonic contexts and during different geological periods (Silver Cliff, CO, USA—Paleogene; El Quevar, Argentina—Miocene; Meissen Volcanic Complex, Germany—Late Carboniferous). All of these megaspherulites have formed exclusively in rhyolitic lava, and their mineral composition is dominated by K-feldspar (sanidine) and SiO2 phases (quartz, cristobalite, tridymite). All megaspherulites represent composite HTCDs, comprising three zones: inner domain (ID), outer domain (OD), and a marginal domain (MD). Early evolution of megaspherulites is characterized by either central cavities and sector- to full-sphere spherulites or dendritic quartz-sanidine domains. The latter consist of bundles of fibrils each radiating from a single point reflecting relatively high growth rates. A common feature of OD and MD of all three megaspherulite occurrences is autocyclic banding. It mainly comprises fibrous (≤ 100 μm length), radially oriented sanidine and quartz, which formed at a temperature close to glass transition temperature (Tg). The termination of megaspherulite growth is marked by centimeter-sized sector-sphere spherulites on the surface. Megaspherulite formation requires limited nucleation, which is probably related to the low phenocryst content of the hosting lava. Latent heat from overlying crystallizing lithoidal rhyolite maintained low undercooling conditions keeping nucleation density low and facilitating high diffusion and growth rates. Late megaspherulite growth and its termination under low diffusion conditions is controlled by cooling close to Tg. Calculations based on literature data suggest that the megaspherulite growth presumably lasted less than 60 years, perhaps 30 to 40 years.

Crystallization and thermal stability effects on tailings glass-ceramics by various heat treating processes

Increasing environmental concerns raise attention on the recycling of mining wastes and smelting of byproducts. As one of the candidate materials, slag glass-ceramics give full play to effective use of tailings resources with excellent performance. In the present research, Bayan Obo tailings are used to produce slag glass-ceramics. However, the effect of the preparation process on the stable behavior and crystallization mechanism of glass-ceramics is still being explored. In this study, different heat treatment processes are used to prepare slag glass-ceramics and its effects on the stability and performance are evaluated through different glass crystallization characteristics. X-ray diffraction (XRD), differential scanning calorimetry (DSC), high-resolution scanning electron microscopy (SEM), Spectral analysis techniques (FT-IR and Raman spectroscopy), and high-temperature thermal imaging system (Tomac) are performed to study and characterize the stable behavior and mechanism of glass-ceramics. Results show that glass-ceramics with heat treatment at 1000 °C exhibit competitive mechanical properties. High crystallization temperature promotes the crystallization of the glass and enhances the growth of crystal grains to optimize the stability and physical properties of the glass-ceramics. In this research, a new process parameter model is provided for process optimization in the industrial production process of glass-ceramics.

Thermal characterizations of basalt fiber-reinforced poly(aryl-ether-ketone) biomedical composites

This research article deals with the development and characterization of poly(aryl-ether-ketone) (PAEK) reinforced with 10 mass%, 20 mass% and 30 mass% of basalt fibers; the samples are titled as PABA 1, PABA 2 and PABA 3, respectively. The composite samples are prepared by hot compression molding process, and test specimens are prepared to ASTM standards. The prepared specimens are subjected to various thermal analyses. The results reveal that differential scanning calorimetry curve shows high crystallization temperature and melting enthalpy for 20 mass% basalt fiber in PAEK composite compared to other composites. The percentage of crystallinity is also higher, which indicates the purity of PABA 2. The same composite shows low mass loss with increase in degradation temperature in the thermogravimetric analysis, due to high heat resistance capacity and thermal barrier of PAEK/basalt fiber at this particular mass%. Dynamic mechanical analysis of 20 mass% basalt fiber PAEK composite shows better storage modulus and low loss modulus compared to 10 and 30 mass% basalt fiber/PAEK composites. The PABA 2 composite has minimum damping coefficient which indicates better stiffness and suitability for high-performance applications. The scanning electron microscope images show a good affinity between the matrix and the fiber in all the composites. Agglomeration of fibers in matrix is observed when loaded beyond 20 mass%; this may be due to lack of melt flow during hot compression.

Resource and sustainable utilization of quartz sand waste by turning into cobalt blue composite pigments

In order to realize the resource and sustainable utilization of quartz sand waste discarded from the mineral processing, Mg2+-doped cobalt blue composite pigments are prepared based on quartz sand via co-precipitation method followed by high-temperature crystallization. The obtained composite pigments are characterized by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and magic angle spinning nuclear magnetic resonance. The results indicate that the incorporation of Mg2+ ion and quartz sand improves the color properties and decreases the production cost of composite pigments, and the color can be facilely adjusted by controlling the added amount of Mg2+. The optimal color properties are obtained as the molar ratio of Mg2+ to Co2+ is 6:4, and Mg2+ enters into the crystal lattice and occupies the tetrahedral sites of spinel cobalt blue. Therefore, this study is expected to develop feasible approach for the resource and sustainable utilization of quartz sand waste, and fabrication of low-cost bright cobalt blue composite pigments as well.

Eu3+ doped high-aluminum cast residue prepared EuCaAl3O7/Ca2Al2SiO7 luminescent material with 5D0→7F2/5D0→7F4 double red intense emission

A series of 5D0→7F2/5D0→7F4 double red-emitting EuCaAl3O7/Ca2Al2SiO7 luminescent materials were prepared by Eu3+ ions doped high-aluminum cast residue, hot state quenched by ice water and high-temperature crystallization. The XRD powder diffraction patterns prove EuCaAl3O7 formation at 950–975 °C. Under the 394 nm excitation, EuCaAl3O7/Ca2Al2SiO7 luminescent materials exhibit 5D0→7F2/5D0→7F4 two red emission peaks of Eu3+ ions 4f-4f transition. The emission peak intensity at 617 nm (5D0→7F2) and 702 nm (5D0→7F4) is enhanced by 6 times and 7 times compared with that before EuCaAl3O7 formation. With the increase of Eu3+ doping concentration, the emission intensity is enhanced up to 17 times (5D0→7F2) and 12 times (5D0→7F4) at 1.5 mol% compared with that at 0.2 mol%. The luminescence quenching test from 30 °C to 150 °C shows that it has good luminescence thermal stability.

β-Relaxation and Crystallization Behaviors in a Pulse-Current-Thermoplastic-Formed La-Based Bulk Metallic Glass.

We use the pulse current thermoplastic forming technique based on joule heating to rejuvenate the atomic structure of a La62Al14Ag2.34Ni10.83Co10.83 bulk metallic glass (BMG). The pulse-formed sample exhibits more pronounced β-relaxation than the as-cast one due to the increased free volume. Instead, the sub-Tg annealing clearly weakens the β-relaxation and also makes it more isolated from the α-relaxation, showing contributions from free volume and preferred structure. However, both treatments exhibit little influence on the following α-relaxation and high temperature crystallization kinetics. Our results open an effective way to rejuvenate the structure of BMGs and provide an in-depth understanding of the relationship between structural relaxations and crystallization kinetics of BMGs.

The Service Characteristics of Complex Boron-Bearing Ferroalloys

The article presents the results of studying the service characteristics of boron-bearing alloys obtained on the basis of ferrosilicon, ferosilicoaluminum. The ferroboron was chosen as reference sample. It is shown that all synthetic alloys have a melting point of less than 1400 °C. Ferroboron has the highest crystallization temperature (1520°C). An increase in silicon concentration from 46 to 79 wt.% leads to a decrease in density from 4640 to 3000 kg/m3. The role of aluminum concentration in alloys in terms of the effect on density is less noticeable due to its low concentration in alloys. The effect of boron on the density of the alloy is minimal since its fraction is ~1%. The calculation of the melting time was carried out on the basis of a mathematical model developed at USTU-UPI and IMET UB RAS. It is shown that the size of ferroalloy lumps has the main effect on the change in their melting time. Alloys up to 10 mm in size show similar melting time (less than 5 seconds). With an increase of the size of particles from 20 to 50 mm, the melting time increases to 2-3 times. The using of particles less than 10 mm is impractical because of losing with fines, and with a diameter of more than 20 mm, the melting time increases significantly. All complex alloys have short melting time and will melt faster than ferroboron.

AlSc Alloy Doped Sb2Te as High Speed Phase-Change Material with Excellent Thermal Stability and Ultralow Density Change

The research progress of global nonvolatile phase change memory (PCM) is quite effective. Among them, chalcogenide Sb2Te is considered as one of the important materials with high operation speed. In this work, we put forward a 1:1 AlSc alloy doped AlSc-Sb2Te to enhance the performance of Sb2Te, including thermal stability, density change and transition speed. Experimental results show that AlSc-Sb2Te has better 10-year data retention temperature (146 °C) and higher crystallization temperature (221 °C), which reflects excellent amorphous thermal stability of AlSc-Sb2Te. X-ray reflection analysis shows that this material has much smaller density change (2.6%) than that of reported phase change materials. Importantly, the AlSc-Sb2Te based device has a very low power consumption of 6.78 × 10−12 J and a high operation speed of 6 ns.

Geochemistry, zircon U–Pb dating, and Hf isotopes composition of Carboniferous granitoids in Xing'an Block, NE China: Record of slab break‐off event in eastern Central Asian Orogenic Belt

The Guang‐Tou‐Shan (GTS) granites, located in the Xing'an Block (XB), record Late Palaeozoic magmatism during the stage of convergence between micro‐blocks in the eastern Central Asian Orogenic Belt (CAOB). We performed a detailed geochronological and geochemical study of GTS granites intending to obtain better constraints on the subduction processes of the Palaeo‐Asian Ocean (PAO) in eastern CAOB. LA–ICP–MS U–Pb dating of zircons from GTS granitic rocks in western XB yielded emplacement ages of 332 ± 2 Ma and 301 ± 2 Ma, respectively, indicating a two‐stage emplacement process. Geochemical analyses show that the Early Carboniferous monzogranite (332 ± 2 Ma) have low values of the A/CNK and A/NK, are enriched in LILE (Rb, Sr, Ba) and LREE (LREE/HREE = 5.6–10.8), and depleted in HFSE (Nd, Ta, Zr, Hf) and P, Ti, which belong to I‐type granites. The Late Carboniferous granodiorite (301 ± 2 Ma) also displays LILE, LREE enrichment, and HFSE depletion with negative Nb–Ta anomalies, and contains relatively high Zr + Nb + Ce + Y contents (495–524 ppm) and high zircon crystallization temperature, indicating the Late Carboniferous granodiorite shows geochemical characteristics similar to those of typical A‐type granites. The two‐stage granitic rocks have εHf(t) values of +7.7 to +11.6 and yield a two‐stage depleted mantle Hf model age of 0.66–0.88 Ga, suggesting that the GTS granitic rocks were derived from partial melting of juvenile arc‐related mafic to intermediate rocks. The results, combined with regional magmatic information, indicate that the eastern CAOB experienced a subduction setting in the Early Carboniferous and extension setting in the Late Carboniferous. This change was most likely caused by the subduction slab break‐off of PAO from the Late Carboniferous.

On Some Unique Specificities of Ge‐Rich GeSbTe Phase‐Change Material Alloys for Nonvolatile Embedded‐Memory Applications

Among the many possible phase‐change materials that can be used in digital memories, Ge‐rich GeSbTe (GGST) alloys are of special interest due to their much higher thermal stability, i.e., the higher crystallization temperature, they offer. However, in contrast to congruent materials which may transit from the amorphous to the crystalline state while keeping the same homogeneous chemical composition, GGST crystallization is obtained through the successive formation of the Ge and GST‐225 phases. For this reason, they show distinct properties and characteristics from those found in the canonical GST‐225 and GeTe alloys. Herein, some of these characteristics, their crystallization kinetics, the effect of N doping and oxidation, and their electrical properties are reviewed and highlighted.

Improvement of ultra-broadband near-infrared emission in Nd3+-Er3+-Pr3+ tri-doped tellurite glasses

Abstract Nd3+-Er3+-Pr3+ tri-doped tellurite glasses with lower phonon energy (766 cm−1) were prepared by conventional melt-quenching method. Under the excitation of 488 nm, an ultra-broadband emission from 1250 to 1650 nm with full-width at half-maximum (FWHM) of about 332 nm was found in Nd3+-Er3+-Pr3+ tri-doped tellurite glass, larger than that of recently reported tellurite glasses. The DSC curve showed that the prepared glass had a high glass transition temperature (Tg = 381 °C) and good crystallization resistance (ΔT = 195 °C). Raman spectra and XRD pattern revealed the information of different vibrational units and the amorphous structure of the prepared glass. The maximum absorption cross-section, emission cross-section and gain coefficient of the prepared tellurite glass were calculated as 1.05 × 10−20 cm2, 1.34 × 10−20 cm2 and 1.55 cm−1, respectively. Compared with the recently reported glasses, these values were improved. This indicates that better laser gain and fluorescence emission could be obtained in the prepared tellurite glass. The results showed that Nd3+-Er3+-Pr3+ tri-doped tellurite glass is a promising near-infrared optical material.

A Novel Bioactive Glass Containing Therapeutic Ions with Enhanced Biocompatibility.

A novel bioactive glass containing therapeutic ions with enhanced biocompatibility was designed and produced by the classical melt-quenching route. Starting from a very promising composition (Bio_MS), which combined bioactivity and high crystallization temperature, the ratio between some oxides was tailored to obtain a new and more reactive (in terms of dissolution rate) bioactive glass, called BGMSN (composition in mol%: 6.1 Na2O, 31.3 CaO, 5 MgO, 10 SrO, 2.6 P2O5, 45 SiO2). The aim of this work was to produce a bioactive glass with a good biological performance, preserving, at the same time, the high crystallization temperature achieved for Bio_MS; this is strategic in order to avoid undesired crystalline phases during thermal treatments, which can undermine the bioactivity and even the stability of final products. A complete characterization of the novel bioactive glass was performed in terms of thermal, mechanical and biological properties and in vitro bioactivity. The thermal behavior of the bioactive glass was studied by heating microscopy, differential thermal analysis (DTA) and optical dilatometry; BGMSN showed a very high crystallization temperature and a high sinterability parameter, thus being suitable for applications where thermal treatments are required, such as sintered samples, coatings and scaffolds. Mechanical properties were investigated by the micro-indentation technique. The in vitro biological properties were evaluated by means of both direct and indirect cell tests, i.e., neutral red (NR) uptake and MTT assay, using murine long bone osteocyte Y4 (MLO-Y4) cells: the cellular viability of BGMSN was higher compared to cellular viability of 45S5, both in direct and indirect tests. Finally, the in vitro bioactivity test by soaking samples in simulated body fluid (SBF) showed high dissolution rate, with a good rate of formation of hydroxyapatite.

Effects of Zn Ratio Tuning on the Structural and Transport Properties of Amorphous Indium Zinc Tin Oxide Thin Films

In this study, various indium zinc tin oxide (IZTO) films were fabricated using co-sputtering to explore amorphous transparent conducting oxides as alternatives to crystalline indium tin oxide (ITO). Various Zn ratios were tuned to study their effects on the structural evolution of IZTO. Amorphous IZTO (aIZTO) films were obtained when the Zn concentration was higher than approximately 17 at.%. X-ray diffraction and transmission electron microscopy analyses indicated that amorphous structures were formed due to the high crystallization temperatures of IZTO and nanocrystalline In2Zn5O8, which also caused aIZTO to exhibit small band gaps. On average, 87% transmittance was achieved in the visible light range. The aIZTO films had substantially higher transmittance in the infrared region than the ITO films did. Samples with Zn ratios between approximately 17 at.% and 27 at.% exhibited resistivity (approximately 3 × 10−4 Ω-cm), mobility (7 cm2 V−1 s−1), and carrier concentrations (4 × 1021 cm−3) comparable to those of crystalline ITO. Thus, the aIZTO films are promising alternative TCO materials. The mechanisms of competition between the crystallinity, oxygen deficiency, high-mobility In2Zn5O8, and electron and hole generation rates were applied to shed light on the excellent electrical and transport properties of aIZTO films.

Titanite in situ SIMS U–Pb geochronology, elemental and Nd isotopic signatures record mineralization and fluid characteristics at the Pusangguo skarn deposit, Tibet

The Pusangguo skarn is a newly discovered Cu-Pb-Zn deposit in the Gangdese metallogenic belt, Tibet. In order to constrain the age of the deposit and the source of hydrothermal fluids, various types of titanite and coexisting minerals in the Pusangguo deposit were studied. The titanite occurring interstitially in fresh granodiorite is magmatic and characterized by high REE, Y, Mn, and Lu/Hf ratios, and high crystallization temperatures (700 to 750 °C). The titanite growing with, or included in, diopside in the prograde endoskarn, or occurring with epidote, calcite, and quartz in the retrograde exoskarn, is hydrothermal titanite characterized by low REE, Y, Mn, and Lu/Hf ratios. The titanite in the retrograde exoskarn typically contains a REE-enriched early core characterized by a negative Eu anomaly, and an overgrowth REE-depleted rim with a positive Eu anomaly. The secondary-ion mass spectrometry U-Pb dating of titanite drilled from thin sections of retrograde exoskarn shows intercept ages of 14.91 ± 0.31 Ma, which are consistent with the granodiorite age (14.63 ± 0.30 Ma), indicating coeval emplacement of granodiorite and skarn mineralization at ~ 14.7 Ma. In addition, in situ epidote and calcite Sr isotopes and titanite Nd isotopes, all analyzed in the same retrograde exoskarn thin section, show similar Sr-Nd isotopic compositions to magmatic plagioclase and granodiorite (whole rock), indicating that the retrograde hydrothermal fluids were directly derived from, or had the same origin as, the granodiorite.