High La Content Research Articles

AI assisted steel cleanness evaluation: Predicting the morphology of La-traced non-metallic inclusions using backscattered-electron images

This study shows how computer vision, a field of artificial intelligence (AI), can be used to gain access to morphological information for a better process understanding and furthermore, how it can be implemented in the evaluation of active tracing experiments. Non-metallic inclusions (NMIs) play a crucial role in determining the chemical and physical properties of the final steel product. The active tracing technique allows for tracking the formation and modification mechanisms of detrimental NMIs throughout the steelmaking process by adding rare earth elements (REEs) to the melt. The interaction of REEs with NMIs results in the formation of traced multiphase particles and, therefore, lead to challenges for accurate evaluation by automated scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS). However, obtaining information about the REE distribution in traced NMIs without extensive, time-consuming human effort is not feasible using the existing method. A two-step classification process with AI was established, which included training and testing of two random forest classifiers (RFC). The first RFC achieved for the binary NMI/non-NMI classification an accuracy of 94.8 %. Four different morphology-based classes were considered in the second classification, whereas traced homogeneous NMIs and NMIs with a high La content got classified with a precision exceeding 90 %. However, caution is required in interpreting results for traced heterogeneous NMIs, as they have a higher prediction error of 37.2 %.

Review on the fatty acid profile and free fatty acid of common carp (Cyprinus carpio)

Carp or ponty in Hungarian, is considered commercial freshwater fish, which is an adaptable species in both wild and cultured conditions. Carp has high nutritional value content, favorable taste, it is rich in protein, and low in saturated fat. The nutritional content in fish is composed of many chemical constituents and influenced by many factors. One of the components that its content may be different due to internal and external factors is fatty acids, which may vary depending on endogenous and exogenous factors. The endogenous or internal factors include the genetic, size, sexual maturity, and life cycle phase. While microclimate, water quality, quality of food or diet habit, and the amount of available food or starvation are considered as exogenous or environmental factors. Freshwater fish has the ability to convert essential fatty acid into long chain polyunsaturated fatty acid like AA, EPA, and DHA. Most results showed that palmitic acid and oleic acid were the dominant SFA and MUFA in carp both for wild and farmed carp in all seasons. The PUFA for wild carp was mainly dominated by DHA, while on farmed carp by LA. It confirmed that high LA content in farmed carp was related to the diet habit. The amount of lipid and FA were changed in line with the season. Even the statistical analysis showed no significant difference, but some studies showed a contrasting result. Moreover, most obtained results acknowledged that FA tends to decrease during the spawning period. The amount and composition of FA were affected by the total lipid content. The lipid must be broken down into simpler compounds such as FA or FFA for the metabolism of fish. The result of metabolism then transported into the utilising tissue and used as energy.

Electrochemical codeposition of La and Fe-group metals in a dicyanamide ionic liquid

Room-temperature electrochemical deposition of lanthanides and their alloys can be achieved employing organic ionic media, such as ionic liquids (ILs). Here, we study the electrochemical (co)deposition of La and Fe-group transition metals from solutions in 1-butyl-1-methyl-pyrrolidinium dicyanamide IL, [BMP][DCA], with controlled water content. We show that electroreduction of La(III) ions starts in the two-component solutions containing La(III) + Me(II) (Me = Co, Fe, or Ni) and no added water in the same potential interval as the electroreduction of respective Me(II). La is thus codeposited with the respective Fe-group metal, as evidenced by voltammetric, microscopic, and X-ray analyses, at considerably more positive potentials than in a solution containing only La(III) ions. Such a promoting effect is not observed in the presence of Cu(I) and Sn(II). Furthermore, the effect of water on the (co)deposition of La and Fe-group metals is systematically investigated. The La-Me (Me = Co, Fe, or Ni) codeposition is inhibited in the presence of moderate amounts of water (up to 0.32 M). At higher water contents, particularly ≥0.32 M H2O in the La(III) + Ni(II) solution, the electroreduction of La starts at more positive potentials than the deposition of Ni. This allows obtaining La-Ni deposits with a high La content. The XPS data indicate that La is present in the deposits in both metallic and oxidized states, even if deposition occurs in a solution with no added water. The results obtained in this study offer valuable insight into the electro(co)deposition of La from IL solutions and contribute to the progress of techniques for producing lanthanide-based functional coatings.

Effect of sintering time on phase, physical properties, microstructure and thermal conductivity of Y(Ba1-x La x )2Cu3O7-δ ceramics

This work investigates the effects of various sintering conditions on phase, physical properties microstructure and thermal conductivity of Y(Ba1-x La x )2Cu3O7-δ where x = 0, 0.05, 0.10, 0.15, 0.20 and 0.25 mol fraction. The sintering conditions involved the sintering temperature of 920 °C and sintering time of 6, 8, 10 and 12 h. It was found that pure phase could be obtained in the samples sintered for 6 h regardless of composition. However, small amount of BaCuO2 secondary phase was obtained at other sintering time. The relatively low density and significantly reduced grain size was obtained in the samples with high La content (e.g. x = 0.20 and 0.25) regardless of the sintering time. This showed that La addition had apparent effects on sintering ability and grain growth. Phase analysis indicated that the structure changed from orthorhombic to tetragonal when the La concentration reached 0.20 and 0.25 mol fraction. SEM images of all ceramics also indicated irregular shaped grains. The effects of variation in density, microstructure and composition on the thermal conductivity of all ceramics were also discussed in details.

Microstructure and discharge performance of Mg-La alloys as the anodes for primary magnesium-air batteries

Magnesium alloys are promising anode candidates for energy storage and conversion devices, which give rise to Mg-air batteries as the main development direction of next generation batteries. However, its commercial application still faces giant challenge. In this study, four types of Mg-xLa (La addition of 1, 3, 5, and 10 wt%) alloys with relatively high La content are prepared as anode materials for Mg-air batteries. The influence of La content on the microstructure and electrochemical performance are systematically investigated. All results indicate that adding 5 wt% La to Mg significantly improves the corrosion resistance and discharge activity, whilst excessive addition would accelerate self-corrosion rate due to the formation of large-area LaMg12 phase. The Mg-5La anode exhibits relatively high discharge platform and stable discharge process, and the specific discharge capacity is 1259.45 mAh g−1 with the anodic efficiency of 57.67% at 20 mA cm−2. This boost can be explained by the ameliorative microstructure in Mg-5La anode, which reduces the extended self-corrosion of α-Mg phase and accelerates the spalling of corrosion products. This work might provide some basic meaningful data for designing the advanced anode materials for Mg-air batteries.

Effect of doping with rare-earth element La in MnCoGe system

<p indent=0mm>MnCoGe is one of the most representative materials that undergoes martensitic transformation in the MM′X system. Because the phase transition temperature of MnCoGe is higher than its magnetic ordering temperature, various methods have been used to decrease the phase transition temperature and realize magneto-structural coupling. However, there are rare reports about the effect of doping with rare-earth elements. In this work, the structures and physical properties of Mn_{1−<italic>x</italic>}La<italic>_x</italic>CoGe compounds with <italic>x</italic>=0, 0.01, 0.02, 0.03, and 0.05 were studied. The introduction of La causes a deficiency of both Mn and Ge atoms in the main phase, which leads to a decrease in the martensitic transformation temperature and the realization of magneto-structural coupling. However, due to its limited ability of deficiency formation, a further increase in the La content leads to large amount of secondary phase instead of a continuous decrease of the phase transition temperature. Additionally, the MnCoGe matrix is found to be divided into small “domains” by the needle-like secondary phase, which is the reason for the large amount of retained austenite phase in the sample with a high La content.

Effect of rare-earth doping on the dielectric property and polarization behavior of antiferroelectric sodium niobate-based ceramics

The lead-free 0.96NaNbO3-0.04CaSnO3 ceramics with rare-earth dopants (La, Sm and Lu) (NCLn100x) were prepared and characterized. It is found that a certain amount of La substitution stabilizes the antiferroelectric (AFE) phase but alleviates the lattice distortion in the fresh samples. Re-entrant-like characteristics are observed in the temperature – dielectric constant curves with the room temperature P phase gradually replaced by a possible R phase. Relaxor-like hysteresis loops with suppressed hysteresis loss and remanent polarization were obtained at high La content, achieving a relatively high Wre of 2.1 J/cm3 at a low electric field (250 kV/cm). The relaxation behaviors of the ferroelectric (FE) domain measured by piezoresponse force microscopy suggest an even long characteristic relaxation time of field-induced FE phase, which is different from the situations of other AFE perovskites. Via an explanatory defected diatomic chain model, we propose that a much larger mass of substitutive ion than the origin one helps to induce low-frequency localized mode, which is believed to be in favor of the formation of polar nano-regions and hence strengthens the dynamic stability of FE phase during electric field loading. Our research provides a further understanding of the tuning strategy for enhancing the antiferroelectricity of the NaNbO3-based system.

Electrical properties and positron annihilation studies of nano-crystalline CoLaxFe2−xO4 prepared by ceramic method

The samples of nano-crystalline CoLaxFe2−xO4 were prepared by ceramic method. The results show the formation of cubic inverse spinel phase for all CoLaxFe2−xO4 samples in addition to impurity phase formation of LaFeO3 for high La content samples. The crystallite sizes for all samples are almost 30 nm. The dielectric measurements show that the presence of La enhances the values of dielectric constant at high temperature, demonstrating Debye relaxation. The DC electric resistivity decreases with La content, suggesting that the conduction phenomenon in these samples is due to hopping of charge carriers. The positron annihilation spectroscopy shows that the large size defects decrease with La for low content samples. However, at higher La content (x = 0.25), the agglomeration of the defects is the dominant process. The CoLa0.25Fe1.75O4 sample shows a different type of defect from other samples. The high electrical resistivity and low tan δ recommend that these samples can be used in power applications that require negligible eddy currents.

Effects of La content in ZrLaON gate dielectric on the interfacial and electrical properties of GaAs metal-oxide-semiconductor devices

GaAs MOS capacitors with ZrLaON as the high-k dielectric layer and LaON as the interfacial passivation layer (IPL) are fabricated and the effects of the La content in ZrLaON on the device performance are investigated. Experimental results show that ZrLaON with a moderate or high La content induces serious moisture absorption, thus deteriorating the interfacial and electrical properties of the device, even with the LaON IPL. By adjusting the La content to a suitable value, e.g. a La/(La + Zr) atomic ratio of 13%, good interfacial and electrical properties can be obtained because the passivating role of La on the defects in ZrON can over-compensate the performance degradation induced by the moisture absorption. With the LaON IPL, further improvements in interfacial and electrical properties can be achieved because the LaON IPL can effectively passivate the As-O, Ga-O and As-As bonds at/near the high-k/GaAs interface.

Stability and mechanical properties of high-La content La–Ni phases by first-principles study

The structural stability, mechanical properties and Debye temperatures of La-rich La–Ni (LaNi, La2Ni3 and LaNi2) phases were studied by a first-principles method. The formation enthalpy indicates that the La-rich phase is stable. As the La content increases, the enthalpy of formation decreases. The bonding of La–Ni is covalent and metallic. The La-d and Ni-d orbitals contribute mainly at the Fermi level. The mechanical properties indicate that the La-rich La–Ni phases are brittle. La2Ni3 has the most prominent anisotropy. The hardness of LaNi, La2Ni3 and LaNi2 are 37.62 GPa, 41.61 GPa and 65.06 GPa, respectively. Those phases have the potential to form a superhard material. LaNi2 has the highest Debye temperature (232.88 K). LaNi2 is the most stable among these phases.

Electrical properties and positron annihilation studies for LaxCoFe2−xO4

The electrical measurements and positron annihilation lifetime spectroscopy (PALS) of LaxCoFe2−xO4 (x = 0.05, 0.1, 0.15, 0.2, 0.25, and 0.3) synthesized by two different techniques (citrate-gel autocombustion and autocombustion flash techniques) were carried out. The dielectric constant (eʹ) and dielectric loss (tan δ) were reduced with La concentration at low La value samples. On contrary, La enhanced the values of eʹ and tan δ at high La content samples. AC-resistance measurement recommended that hopping conduction prevails in the studied samples. PALS indicated that defects present at grains’ boundaries and vacancy-type defects in the structure are not changed with different La3+ contents. PALS also indicated the presence of large free volume regions between grains. Finally, it is recommended that these prepared samples are preferable for use in applications like microwave devices, actuators, isolators, and phase shifters.

Microstructure evolution and mechanical properties of Al-La alloys with varying La contents

The microstructure evolution and mechanical properties under different temperature of as-cast Al-La alloys with varying La contents were investigated by X-ray diffraction (XRD), field-emission scanning electron microscope (FESEM), energy dispersive spectrometer (EDS) and tensile test (Gleeble 3500). The results revealed that the phase compositions of Al-xLa (x = 10, 15, 20) alloys were α-Al and Al11La3. Comparing with Al-10La, the mechanical properties of Al-15La and Al-20La were deteriorated due to the formation of strip-shaped and particle-shaped primary Al11La3 phase respectively. The influence of Al11La3 phase on tensile strength has a downward trend with the increasing temperature, and elevated temperature is more helpful to increase the plasticity of Al-La alloys with high La content. According to the tensile fracture of the three Al-La alloys at temperature range from 200°C to 500°C, Al-10La tended to be highly dimples driven, and dimples became larger and deeper with increasing temperature, which demonstrated a growing ability to avoid crack extension. There was a transformation from cleavages to dimples in Al-15La and Al-20La with increasing temperature, but the dimples were small and shallow indicating lower plasticity than Al-10La.

Lanthanum immobilization by iron and aluminum colloids

In this work, lanthanum (La) removal from aqueous solution with Al–Fe (hydr)oxides was evaluated and the precipitated materials characterized. We synthesized Al–Fe (hydr)oxides from sulfate salts in water with different La concentrations. The molar ratios of Fe/Al/La were: 500:125:0, 500:125:1, 500:125:5, 500:125:25, 500:125:125, 500:250:0, 500:250:1, 500:250:5, 500:250:25 and 500:250:125. The suspensions were aged for 90-day period, and supernatant samples were periodically collected during this time. The precipitated materials were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), coupled with system energy-dispersive spectroscopy (EDS). The potential for remobilization of lanthanum from the solid phases comparing the extractable La by acetic acid 0.11 mol L−1 with the total concentration (by acid dissolution with HCl/HNO3 3:1 v/v) was evaluated. All treatments reached high removal of La from contaminated water. Goethite, lepidocrocite and magnetite with structural Al were detected by XRD analysis. SEM–EDS microanalysis showed lanthanum associated with Al–Fe colloids at low La/Fe ratios, but lanthanum segregation was detected to the higher La/Fe ratio. Acetic acid extraction indicated high potential for La remobilization from precipitates, especially in the treatments with high La content. High pH in precipitation of Al–Fe (hydr)oxides provided an efficient removal of soluble lanthanum from contaminated water, but further investigation in conditions that favor the retention of the contaminant was necessary to optimize the immobilization. At high La/Fe ratios, lanthanum could be easily recovered from solid phases by 0.11 M acetic acid leaching.

U–Pb Dating of Hydrothermal Zircons from the Neoproterozoic Liushanyan VMS Cu–Zn Deposit, Central China: Evidence for a Triassic Deformation Event

AbstractThe Liushanyan deposit is an important volcanic‐host massive sulfide (VMS) Cu–Zn deposit in the Qinling‐Tongbai‐Dabie orogenic belt, central China, with reserve of 2.38 Mt Cu and 16.11 Mt Zn. Orebodies occur in the meta‐quartz keratophyre of the Liushanyan formation. In this paper, we present textural features and laser ablation ICP‐MS U–Pb dating results of zircons from the ore‐bearing mylonitized meta‐quartz keratophyre. The hydrothermal zircons are distinct from metamorphic zircons in this rock, showing low cathodoluminescence (CL) response and hydrothermal rims (black in CL images). They have relatively flat light rare earth element patterns and high La content and low (Sm/La)N and Ce/Ce* values. These features are typical of hydrothermal zircons. The cores of metamorphic zircons yield a weighted mean 206Pb/238U age of 900 ± 26 Ma, interpreted as the volcanic and related VMS mineralizing age. Two much younger events are also recorded by zircons in this rock: (i) the Early Silurian amphibolites–greenschist facies metamorphism at 435 ± 26 Ma; and (ii) the growth of hydrothermal zircons at ca. 241 ± 1 Ma, associated with the ductile shear deformation. The Silurian metamorphic event is probably associated with the arc–continent collision, while the Triassic ductile deformation event formed in the final continent–continent collision setting.

Enhanced photoactivity for the phenol mineralization on ZnAlLa mixed oxides prepared from calcined LDHs

ZnAlLa layered double hydroxides (La/Zn molar ratio of 0.005, 0.01 and 0.03) were synthesized by the co-precipitation method and calcined at 500°C. XRD patterns showed lamellar type materials in fresh solids (dried) and a diminishing basal parameter denoting the incorporation of La in the ZnAl LDH structure. At low content of La, XRD does not show the formation of La2O3, which become detectable only in the sample with high La content. After calcination, the formation of zincite was detected in the LDH, indicating the destruction of the lamellar structure. The Eg band of the sample with low content of La, calculated from the UV–Vis spectra, showed a shift to low energy, while for the samples with high content of La the Eg shift is displaced to high absorption energy. Evaluation of the photoactivity in the degradation of phenol using a low intensity UV–Vis lamp (254nm and 4400μW/cm2), showed the maximum values in phenol mineralization 88–66% with the ZnAlLa samples, in comparison to that obtained with the ZnAl oxide (48%). These results show that ZnAlLa mixed oxides prepared from the thermal treatment of ZnAlLa LDH are promising materials for an effective phenol mineralization.

Tri-component copolymer rods as an implantable reservoir drug delivery system for constant and controllable drug release rate

Copolymers of (D,L-lactide-random-e-caprolactone)-block-poly(ethylene glycol)-block-(D,L-lactide-random-e-caprolactone) (PLECs) were synthesized with varied D,L-lactide (LA) content and different molecular weights (20 and 50 kDa). Polymer ratios, particularly the content of LA, had significant effect on the release of trypan blue. A lower trypan blue release rate was observed from monolithic rods composed of PLECs with higher CL/LA ratio. High LA content in polymer rod led to increase of the hydrophilicity of the polymer rod and the decrease of CL content resulted in the increase of the hydrophilicity of PLECs and hydrolysis rate. Spin-coating technique was employed to coat PCL-b-PEG-b-PCL membrane on PLEC rod with controlled thickness. Results showed that membrane encased rods can produce different release pattern including delayed release, zero-ordered release and burst release depending on the types of inner rod and membrane. Results for this study indicated that PLEC rods could provide the zero-order release profile of highly water-soluble molecules. Moreover, the longer lag phase was observed at higher thickness. These results suggest that these polymer rods were potential drug delivery systems that can provide controlled drug release profiles.

Folic Acid-Conjugated LaF3:Yb,Tm@SiO2 Nanoprobes for Targeting Dual-Modality Imaging of Upconversion Luminescence and X-ray Computed Tomography

Development of multimodal contrast agents for in vivo simultaneous multimodality imaging is an emerging interdiscipline that is paving the avenue toward the goal of personalized medicine. Herein, folic acid-conjugated silica-modified LaF(3):Yb,Tm upconversion nanoparticles (UCNPs@SiO(2)-FA) with high La content in a single particle were strategically designed and prepared for simultaneously targeting dual-modality imaging of upconversion luminescence (UCL) and X-ray computed tomography (CT). LaF(3) UCNPs were synthesized by a novel oleic acid (OA)/ionic liquid (IL) two-phase system. Afterward, a folic acid molecule was covalently anchored on the surface of UCNPs with a silane coupling agent. The UCNPs@SiO(2)-FA exhibits good stability, water dispersibility and solubility, low cytotoxicity, good biocompatibility, highly selective targeting, excellent X-ray attenuation, and UCL emission under excitation at 980 nm. In vivo UCL and CT images of mice show the UCNPs@SiO(2)-FA can be used in targeting dual-modality imaging. These results suggest that the as-prepared nanoprobe is a good candidate with excellent imaging and targeting ability for targeting dual-modality imaging of UCL and CT.

SHRIMP U-Pb DATING ON HYDROTHERMAL ZIRCONS: EVIDENCE FOR AN EARLY CRETACEOUS EPITHERMAL EVENT IN THE MIDDLE JURASSIC DEXING PORPHYRY COPPER DEPOSIT, SOUTHEAST CHINA

The Dexing porphyry copper deposit, part of the circum-Pacific porphyry copper ore belt, is the largest porphyry copper deposit in China (1,500 million tonnes [Mt] of ore at 0.43% Cu, 0.02% Mo, and 0.16 grams per tonne Au, approximately equivalent to 6.45 Mt Cu, 0.25 Mt Mo, and 24 tonnes Au). We report results of sensitive high resolution ion microprobe (SHRIMP) U-Pb dating on zircons separated from a thick (~20-cm-wide) pyrite-chalcopyrite-quartz vein in this deposit, which is mineralogically and texturally different from the porphyry-related ore-bearing thin quartz veins. The zircons from the thick quartz vein are unzoned and nonluminescent (black) in the cathodoluminescence images. They show relatively flat light rare-earth element patterns and have high La content and low (Sm/La)N and Ce/Ce* values. These features are typical of hydrothermal zircons. SHRIMP U-Pb dating on these hydrothermal zircons yielded weighted mean 206Pb/238U ages of 106.5 ± 0.9 and 100.9 ± 3.5 Ma, which are ca. 70 m.y. younger than the ages (172–171 Ma) of the ore-bearing porphyries and the molybdenite Re-Os ages (170.9 ± 1.1 Ma) of the porphyry-related disseminated and veinlet (usually <1 cm in width) ores. This suggests the occurrence of a younger, distinct Cu (Au?) hydrothermal event superimposed on the porphyry Cu-Mo-Au mineralization at Dexing. The mineralogical features and age of this hydrothermal event suggest that it could belong to the metallogenic event responsible for the formation of the late Early Cretaceous to early Late Cretaceous (110–95 Ma) epithermal Cu-Au-Ag deposits in southeast China.

Controllable hydrogen generation performance from Al/NaBH4 composite activated by La metal and CoCl2 salt in pure water

A novel composition of Al/NaBH4 mixture activated by La and CoCl2 in water for hydrogen generation was investigated. The composition had good stability at 298 K with high La content and low CoCl2 content, but presented good hydrogen generation performance with increasing global temperature. For example, The Al-15 wt.%La-5 wt.%CoCl2/NaBH4 mixture (mass ratio of 1:1) yielded 1664 ml hydrogen/1 g mixture with 100% efficiency within 60 min at 333 K. The hydrogen generation rate and amount could be regulated by changing composition design, hydrolytic conditions, etc. There existed a synergistic effect of La and CoCl2. Increasing La content was helpful to decrease crystal size of the mixture, but its hydrolysis byproduct La(OH)3 deposited on Al surface and had side effect on Al hydrolysis. Increased CoCl2 content was attributed to the producing of more actively catalytic sites Co2B/Al(OH)3 formed in the hydrolytic process. Co2B had dual catalytic effect on Al/NaBH4 hydrolysis. It deposited on Al surface and acted as a cathode of a micro galvanic cell. Co2B/Al(OH)3 was also a good promoter to NaBH4 hydrolysis. Therefore, the Al/NaBH4 mixture activated by La and CoCl2 may be applied as hydrogen generation material and the experimental data lays a foundation for designing practical hydrogen generators.

Quasi-one-dimensional domain walls in ferroelectric ceramics: Evidence from domain dynamics and wall roughness measurements

Direct measurements of the motion of domain walls in disordered ferroelectrics provide important information on their interaction with defects, which is crucial for the functioning of various ferroelectric devices such as high-K capacitors and ferroelectric-based memories. In this work, we report on the results of the nanoscale measurements of domain-wall velocity and static domain-wall roughness in disordered (Pb,La)(Zr,Ti)O3 (PLZT) ceramics prepared by hot press sintering. Relaxation of domain walls to their equilibrium configurations at short length scales yields the apparent roughness exponent ζ ≈ 0.67 in PLZT 9.5/65/35. At the same time, the dynamical exponent μ was found to be about 0.25 from the independent measurements of domain-wall creep under local application of electric field. An analysis of these two values points to the effective dimensionality deff = 1 for the domain walls in PLZT with high La content. This result is confirmed by the layer-by-layer polishing followed by the imaging of an artificially created domain. The origin of disorder and its dependence on La concentration in PLZT solid solutions are discussed.