Mechanical properties and acoustic emission characteristics of mixed granite after different numbers of freeze‒thaw cycles.

The mechanical properties of rocks in cold regions undergo significant changes as a result of decades of freeze‒thaw cycles with seasonal variations, which can lead to a series of geological disasters, such as collapse. This study investigates the evolution of the mechanical characteristics and internal progressive damage characteristics of mixed granite under freeze‒thaw cycling and axial loading. By measuring the mass, wave velocity, and uniaxial compressive strength of rock samples and combining these metrics with acoustic emission (AE) characteristics, the physical and mechanical properties and microfracture development of mixed granite after different numbers of freeze‒thaw cycles were investigated. The results indicate that as the number of freeze‒thaw cycles increases, the longitudinal wave velocity, uniaxial compressive strength, and elastic modulus of the mixed granite decrease nonlinearly, while the peak strain gradually increases. Combined with the stress‒strain curve, the AE characteristics can be divided into four stages. As the number of freeze‒thaw cycles increases, the AE cumulative count decreases, and the AE counts of the four stages are different. The low-frequency-high-amplitude signals first increases and then tends to stabilize, and they only appeared in the third and fourth stages. At the same time, the proportion of the low-frequency ratio gradually increases, and the proportion of the high-frequency ratio decreases. In addition, based on the rise time/amplitude (RA) and average frequency (AF) characteristics and failure modes, it was found that the internal crack types of mixed granite transition from shear cracks to tensile cracks, among which tensile cracks play a crucial role in rock failure.

Associations of prenatal blood pressure trajectory and variability with child neurodevelopment at 2 years old.

BACKGROUND: The patterns of blood pressure (BP) change throughout the pregnancy were related to adverse birth outcomes. However, little is known about the long-term effect of BP change patterns on child neurodevelopment. This study aimed to explore the relationship between the BP trajectory and BP variability during pregnancy and early childhood neurodevelopment. METHOD: A total of 2797 mother-newborn pairs were derived from the Wuhan Healthy Baby Cohort Study. BP was measured during each antenatal visit, and Mental and Psychomotor Development Indexes (MDI and PDI) were assessed using the Bayley Scales of Infant Development (BSID) when the children were 2 years old. Delayed neurodevelopment was defined as scores of PDI or MDI less than - 1SD relative to the mean score of the study population. A group-based multi-trajectory model was adopted to identify multi-trajectories of systolic blood pressure (SBP) and diastolic blood pressure (DBP). Visit-to-visit BP variability was assessed by the coefficient of variation (CV), standard deviation (SD), and average real variability (ARV). Generalized linear models and multivariate logistic regressions were used to assess the associations of BP trajectories and variability with BSID scores and delayed neurodevelopment, respectively. RESULTS: Five distinct trajectories for SBP and DBP were identified, namely, "Low-increasing," "Low-stable," "Moderate-decreasing," "Moderate-increasing," and "High-stable" groups. Compared with the "Low-stable" group, the children whose mothers' BP fell into the other four groups had lower PDI scores, and mothers in the "Low-increasing," "Moderate-increasing," and "Moderate-decreasing" groups had 43% (OR: 1.43, 95% CI: 1.01, 2.03), 48% (OR: 1.48, 95% CI: 1.05, 2.08) and 45% (OR:1.45, 95% CI: 1.03, 2.04) higher risk of having offspring with delayed psychomotor neurodevelopment, respectively. High DBP variability was associated with lower BSID scores, and delayed psychomotor neurodevelopment (OR = 1.46, 95% CI: 1.10, 1.92 for DBP-SD; OR = 1.53, 95% CI: 1.16, 2.02 for DBP-CV). CONCLUSION: Our findings suggest that BP change patterns assessed by multi-trajectory and visit-to-visit variability were associated with lower BSID scores and delayed neurodevelopment. Health professionals should be aware of the influence of BP level and its oscillations during pregnancy on the risk of delayed neurodevelopment.

Rigid Phase Formation and Sb3+ Doping of Tin (IV) Halide Hybrids toward Photoluminescence Enhancement and Tuning for Anti-Counterfeiting and Information Encryption.

Multi-excitonic emitting materials in luminescent metal halides are emerging candidates for anti-counterfeiting and information encryption applications. Herein, ATPP2SnCl6 (ATPP = acetonyltriphenylphosphonium) phase was designed and synthesized by rationally choosing emissive organic reagent of ATPPCl and non-toxic stable metal ions of Sn4+, and Sb3+ was further doped into ATPP2SnCl6 to tune the photoluminescence with external self-trapped excitons emission. The derived non-toxic ATPP2SnCl6 shows multi-excitonic luminescent centers verified by optical study and differential charge-density from density functional theory calculations. Incorporation of Sb3+ dopants and the increasing concentrations induce the efficient energy transfer therein, thus enhancing photoluminescence quantum yield from 5.1% to 73.8%. The multi-excitonic emission inspires the creation of information encryption and decryption by leveraging the photoluminescence from ATPPCl to ATPP2SnCl6 host and ATPP2SnCl6:Sb3+. This study facilitates the anti-counterfeiting application by employing solution-processable luminescent metal halides materials with excitation-dependent PL properties.

Ratiometric Fluorescence Optical Fiber Enabling Operando Temperature Monitoring in Pouch-Type Battery.

Thermal characteristics are essential for improving the performance and monitoring the status of Li-ion batteries (LIBs). However, it is a challenge to design efficient and facile sensing materials for the detection of the in situ temperature of a working LIB. Herein, a ratiometric fluorescence optical fiber is developed and real-time temperature monitoring is performed with a measurement accuracy of 0.12 °C, and the feasibility based on this polymer optical fiber composed of NaLaTi2O6:Yb/Er phosphors is verified in a pouch-type battery. During the charging and discharging cycles, the in situ temperature is instantaneously conveyed, revealing the internal situation of LIBs. This article further dwells on the thermal characteristics in constant current (CC)/constant voltage charging and CC discharging processes at different C-rates and the battery failure when operated at low temperatures (0 °C). This work demonstrates an innovative strategy for operando solitary temperature monitoring conducted by ratiometric fluorescence optical fiber.

In situ and Real-time Monitoring the Chemical and Thermal Evolution of Lithium-ion Batteries with Single-crystalline Ni-rich Layered Oxide Cathode.

High-capacity Ni-rich layered oxides are promising cathode materials for fabrication of lithium-ion batteries (LIBs) with high energy density. However, thermal runaway of LIBs with these cathodes leads to great safety concerns. In this study, single crystalline LiNi0.9Co0.05Mn0.05O2 (NCM-SC) has been prepared and a flexible optical fiber was buried inside the pouch-type LIBs with NCM-SC cathode to in situ study its real-time temperature evolution during charge/discharge process. NCM-SC exhibits an enhanced Li+ ions transportation efficiency and electrode reaction kinetics, which can effectively reduce the generation of polarization heat and mitigate the internal temperature rise of the pouch-type battery. Meanwhile, solid-electrolyte interface (SEI) film decomposition and gas accumulation are effectively alleviated, due to the enhanced thermal stability of SEI film formed on NCM-SC. Moreover, the single crystal architecture can effectively retard layered to spinal and rock-salt phase transition, mitigate the crack formation and structural collapse. Consequently, NCM-SC exhibits an excellent electrochemical performance and enhanced thermal stability.

Rapid synthesis of phosphor-glass composites in seconds based on particle self-stabilization.

Phosphor-glass composites (PGC) are excellent candidates for highly efficient and stable photonic converters; however, their synthesis generally requires harsh procedures and long time, resulting in additional performance loss and energy consumption. Here we develop a rapid synthetic route to PGC within about 10 seconds, which enables uniform dispersion of Y3Al5O12:Ce3+ (YAG:Ce) phosphor particles through a particle self-stabilization model in molten tellurite glass. Thanks for good wettability between YAG:Ce micro-particles and tellurite glass melt, it creates an energy barrier of 6.94 × 105 zJ to prevent atomic-scale contact and sintering of particles in the melt. This in turn allows the generation of YAG:Ce-based PGC as attractive emitters with high quantum efficiency (98.4%) and absorption coefficient (86.8%) that can produce bright white light with luminous flux of 1227 lm and luminous efficiency of 276 lm W-1 under blue laser driving. This work shows a generalizable synthetic strategy for the development of functional glass composites.

Narrow-Band Green-Emitting Hybrid Organic-Inorganic Eu (II)-Iodides for Next-Generation Micro-LED Displays.

Low-dimensional metal halide perovskites are an emerging class of light-emitting materials for LED-based displays; however, their B-site cations are confined to ns2, d5, and d10 metals. Here, the design of divalent rare earth ions at B-site is presented and a novel Eu(II)-based iodide hybrid is reported with efficient (PLQY ≈98%) narrow-band (FWHM ≈43 nm) green emission and high thermal stability (97%@150 °C). Owing to reduced lattice vibrations and shrunken average distance of Eu(II)-iodide bonds in the face-sharing 1D-structure, photoluminescence from Eu(II) 4f-5d transition appears along with elevated crystal-field splitting of 5d energy level. The Eu(II)-based iodide hybrid is further demonstrated for color-pure green phosphor-converted LEDs with a maximum brightness of ≈396 000 cd m-2 and photoelectric efficiency of 29.2%. High-resolution micrometer-scale light-emitting diode (micro-LED) displays (2540 PPI) via the solution-processed screen is also presented. This work thus showcases a compelling narrow-band green emitter for commercial micro-LED displays.

Near-Infrared Light Emitting Metal Halides: Materials, Mechanisms, and Applications.

Near-Infrared (NIR) light emitting metal halides are emerging as a new generation of optical materials owing to their appealing features, which include low-cost synthesis, solution processability, and adjustable optical properties. NIR-emitting perovskite-based light-emitting diodes (LEDs) have reached an external quantum efficiency (EQE) of over 20% and a device stability of over 10,000 h. Such results have sparked an interest in exploring new NIR metal halide emitters. In this review, several different types of NIR-emitting metal halides, including lead/tin bromide/iodide perovskites, lanthanide ions doped/based metal halides, double perovskites, low dimensional hybrid and Bi3+/Sb3+/Cr3+ doped metal halides, are summarized, and their recent advancement is assessed. The characteristics and mechanisms of narrow-band or broadband NIR luminescence in all these materials are discussed in detail. Also, the various applications of NIR-emitting metal halides are highlighted and an outlook for the field is provided.

Multisite Fine-Tuning in Hybrid Cadmium Halides Enables Wide Range Emissions for Anti-Counterfeiting.

Achieving tunable emissions spanning the spectrum, from blue to near-infrared (NIR) light, within a single component is a formidable challenge with significant implication, particularly in tailoring multicolor luminescence for anti-counterfeiting purposes. In this study, we demonstrate a broad spectrum of emissions, covering blue to red and extending into NIR light in [BPy]2CdX4 : xSb3+ (BPy=Butylpyridinium; X=Cl, Br; x=0 to 0.08) through precise multisite structural fine-tuning. Notably, the multicolor emissions from [BPy]2CdBr4 : Sb3+ manifest a distinctive pattern, transitioning from blue to yellow in tandem with the host [BPy]2CdBr4 and further extending from yellow to NIR with its homologous [BPy]2CdCl4 : Sb3+, resulting in the simultaneous presence of intersecting and independent emission colors. Detailed modulation of chemical composition enables partial luminescence switching, facilitating the creation of diverse patterns with multicolor luminescence by employing [BPy]2CdX4 : xSb3+ as phosphors. This study for the first time successfully implements several groups of tunable emission colors in a single matrix via multisite fine-tuning. Such an effective strategy not only develops the specific relationships between tunable emissions and adjustable compositions, but also introduces a cost-effective and straightforward approach to achieving unique, high-level, plentiful-color and multiple-information-storage labels for advanced anti-counterfeiting applications.

Multiple Energy Transfer Channels in Rare Earth Doped Multi-Exciton Emissive Perovskites.

Revealing the energy transfer (ET) process from excitons to rare earth ions in halide perovskites has great guiding value for designing optoelectronic materials. Here, the multiple ET channels in multi-exciton emissive Sb3+ /Nd3+ co-doped Cs2 ZrCl6 are explored to comprehend the ET processes. Förster-Dexter ET theory reveals that the sensitizer concentration rather than the overlap integral of the spectra plays the leading function in the comparison of the ET efficiency among multiple ET channels from the host self-trapped excitons (STEs) and dopant triplet STEs to Nd3+ ions. Besides, Sb3+ /Nd3+ co-doped Cs2 ZrCl6 enables varied color delivery and has great potential as anti-counterfeiting material. Under X-ray irradiation, Sb3+ /Nd3+ co-doped Cs2 ZrCl6 presents a high light yield of ≈13300 photons MeV-1 and promising X-ray imaging ability. This work provides new insight for investigating the ET efficiency among multiple ET processes and presents great potentiality of multi-exciton emissive perovskites in the fields of anti-counterfeiting and X-ray imaging.

In situ recrystallization of zero-dimensional hybrid metal halide glass-ceramics toward improved scintillation performance.

Zero-dimensional (0D) hybrid metal halide (HMH) glasses are emerging luminescent materials and have gained attention due to their transparent character and ease of processing. However, the weakening of photoluminescence quantum efficiency from crystal to glass phases poses limitations for photonics applications. Here we develop high-performance glass-ceramic (G-C) scintillators via in situ recrystallization from 0D HMH glass counterparts composed of distinct organic cations and inorganic anions. The G-C scintillators maintain excellent transparency and exhibit nearly 10-fold higher light yields and lower detection limits than those of glassy phases. The general in situ recrystallization within the glass component by a facile heat treatment is analyzed via combined experimental elaboration and structural/spectral characterization. Our results on the development of G-Cs can initiate more exploration on the phase transformation engineering in 0D HMHs, and therefore make them highly promising for large-area scintillation screen applications.

Associations of prenatal exposure to bisphenols with BMI growth trajectories in offspring within the first two years: evidence from a birth cohort study in China.

BACKGROUND: Prenatal bisphenol exposure has been reported to be associated with lower birth weight and obesity-related indicators in early childhood. These findings warrant an investigation of the relationship between prenatal bisphenol exposure and the dynamic growth of offspring. This study aimed to evaluate the relationship of maternal bisphenol concentration in urine with the body mass index (BMI) growth trajectory of children aged up to two years and to identify the critical exposure periods. METHODS: A total of 826 mother-offspring pairs were recruited from Wuhan Children's Hospital between November 2013 and March 2015. Maternal urine samples collected during the first, second, and third trimesters were analyzed for bisphenol A (BPA), bisphenol S, and bisphenol F (BPF) concentrations. Measurements of length and weight were taken at 0, 1, 3, 6, 8, 12, 18, and 24 months. Children's BMI was standardized using the World Health Organization reference, and group-based trajectory modeling was used to identify BMI growth trajectories. The associations between prenatal bisphenol exposure and BMI growth trajectory patterns were assessed using multinomial logistic regression models. RESULTS: The BMI growth trajectories of the 826 children were categorized into four patterns: low-stable (n = 134, 16.2%), low-increasing (n = 142, 17.2%), moderate-stable (n = 350, 42.4%), and moderate-increasing (n = 200, 24.2%). After adjusting for potential confounders, we observed that prenatal exposure to BPA during the second trimester [odds ratio (OR) = 2.20, 95% confidence interval (CI) = 1.09-4.43] and BPF during the third trimester (OR = 3.28, 95% CI = 1.55-6.95) at the highest quartile concentration were associated with an increased likelihood of the low-increasing BMI trajectory. Furthermore, in the subgroup analysis by infant sex, the positive association between the highest quartile of prenatal average urinary BPF concentration during the whole pregnancy and the low-increasing BMI trajectory was found only in girls (OR = 2.82, 95% CI = 1.04-7.68). CONCLUSION: Our study findings suggest that prenatal exposure to BPA and BPF (a commonly used substitute for BPA) is associated with BMI growth trajectories in offspring during the first two years, increasing the likelihood of the low-increasing pattern. Video Abstract (MP4 120033 kb).

Crystal-glass phase transition enabling reversible fluorescence switching in zero-dimensional antimony halides.

Crystal-glass phase transition in luminescent metal halides provides unique opportunities to tune the photoluminescence. Here we report four zero-dimensional Sb-based halide glasses featuring reversible phase transition upon heating and acetone triggering conditions, along with modulated luminescence properties. Benefiting from the fluorescence switching, information encryption and anti-counterfeiting applications are achieved.

Thermally Stable Red-Emitting Oxide Ceramics for Laser Lighting.

Laser-driven phosphor-converted white light sources are highly desirable for their unprecedented energy efficiency and lighting quality. However, important challenges remain due to a lack of efficient and stable red-emitting materials. Here Eu2+ -activated oxide-based double perovskites are explored as red emitters with thermally stable photoluminescence. Sr3 TaO5.5 :Eu2+ ceramics exhibit a red emission band peaking at 620 nm upon blue laser pumping owing to the Eu2+ occupation at highly ordered substitutional lattice sites. A constructed laser-driven white light wheel under an incident power density of 19.2 W mm-2 presents a record luminous flux of 1115 lm with an excellent color rendering index of 90. This study invigorates the development of Eu2+ -activated oxide-based ceramics with thermally stable luminescence for laser-pumped lighting and display applications.

Multi-sites energy transfer in Fe3+-doped KAl11O17 phosphor toward zero thermal quenching near-infrared luminescence.

Near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) have demonstrated great potential for optoelectronic and biomedical applications, while the exploration of NIR phosphors with high thermal stability remains a challenge. Herein, we report an NIR phosphor KAl11O17:Fe3+ with zero thermal quenching (TQ) behavior up to 200°C. The asymmetrical broadband NIR emission with three sub-bands centered at 700, 770, and 800 nm is related to the superposition of different Fe3+ emission centers located in Al2O4, Al3O6, and Al4O6 sites of the KAl11O17 host, respectively. Temperature- and Fe3+ concentration-dependent emission spectra verify that the energy transfer (ET) between multiple Fe3+ emitters and the weak electron-phonon coupling (EPC) effect contribute to the thermally stable broadband NIR emission. The fabricated NIR pc-LED using optimized KAl11O17:Fe3+ phosphor exhibits great potential in information encryption applications.

Occurrence, distribution, and ecological risk assessment of artificial sweeteners in surface and ground waters of the middle and lower reaches of the Yellow River (Henan section, China).

As a new class of water contaminants, artificial sweeteners (ASs) have attracted much attention due to their environmental persistence and potential adverse effects to human and the environment. This study systematically investigated the occurrence and distribution of four commonly used ASs in the effluent of wastewater treatment plants (WWTPs), surface water and groundwater in the middle and lower reaches of the Yellow River (Henan section). Sucralose (SUC) was dominant in WWTP effluents and had the highest mass loading. Acesulfame (ACE), cyclamate (CYC), saccharin (SAC), and SUC were consistently detected in surface water at concentrations ranging from 1.364 ng/L (CYC) to 7786 ng/L (ACE). Spatial analysis showed that the pollution level of ASs in the trunk stream was lower than that in most tributaries. The total concentrations of ASs detected in surface water ranged between 308.7 and 10,498 ng/L, while in groundwater, the total concentration of ASs detected was between ND-4863 ng/L. ACE and SUC are the main pollutants in surface water and groundwater within this survey area. The risk assessment showed that the risks of the four target ASs to aquatic organisms were negligible (risk quotient (RQ) values < 0.1), and the maximum risk quotient of the mixtures (MRQ) values of all rivers were all much less than 0.1.

Energy-Trapping Management in X-Ray Storage Phosphors for Flexible 3D Imaging.

X-ray imaging has received sustained attention for healthcare diagnostics and nondestructive inspection. To develop photonic materials with tunable photophysical properties in principle accelerates radiation detection technologies. Here the rational design and synthesis of doped halide perovskite CsCdCl3 :Mn2+ , R4+ (R = Ti, Zr, Hf, and Sn) are reported as next generation X-ray storage phosphors, and the capability is greatly improved by trap management via Mn2+ site occupation manipulation and heterovalent substitution. Specially, CsCdCl3 :Mn2+ , Zr4+ displays zero-thermal-quenching (TQ) radioluminescence and anti-TQ X-ray-activated persistent luminescence even up to 448 K, further revealing the charge-carrier compensation and redeployment mechanisms. X-ray imaging with the resolution of 12.5 lp mm-1 is demonstrated, and convenient 3D X-ray imaging for the curved objects is realized in a time-lapse manner. This work demonstrates efficient modulation of energy traps to achieve high storage capacities and promote future research into flexible X-ray detectors.

Multiexciton Generation from a 2D Organic-Inorganic Hybrid Perovskite with Nearly 200% Quantum Yield of Red Phosphorescence.

2D organic-inorganic hybrid perovskites (OIHPs) show obvious advantages in the field of optoelectronics due to their high luminescent stability and good solution processability. However, the thermal quenching and self-absorption of excitons caused by the strong interaction between the inorganic metal ions lead to a low luminescence efficiency of 2D perovskites. Herein, a 2D Cd-based OIHP phenylammonium cadmium chloride (PACC) with a weak red phosphorescence (ΦP  < 6%) at 620 nm and a blue afterglow is reported. Interestingly, the Mn-doped PACC exhibits very strong red emission with nearly 200% quantum yield and 15 ms lifetime, thus resulting in a red afterglow. The experimental data prove that the doping of Mn2+ not only induces the multiexciton generation (MEG) process of the perovskite, avoiding the energy loss of inorganic excitons, but also promotes the Dexter energy transfer from organic triplet excitons to inorganic excitons, thus realizing the superefficient red-light emission of Cd2+ . This work suggests that guest metal ions can induce host metal ions to realize MEG in 2D bulk OIHPs, which provides a new idea for the development of optoelectronic materials and devices with ultrahigh energy utilization.