Higher Decay Rate Research Articles

Swapping conventional doping with novel white light emission from La2O3: clitoria ternatea extract

The common flower Clitoria ternatea is gifted with organic dyes anthocyanin delphinidin and betalains betacyanin that exhibit broad emission peaks centered at 490 nm and 630 nm. These fresh emission bands in the blue-green and red regions make it a potential white light source that can swap the conventional rare-earth doped phosphor materials. By this line, the extract shows decent emission in its solution state. However, the emission intensity reduces rapidly after a while, owing to the high decay rate of organic dyes in their pure form. Thus, the floral extract is combined with the antioxidant La2O3, reducing the luminescence decay to a noticeable value. The complex formation does not alter the innate La2O3 crystal structure, identified by the XRD peaks, but aids with near-white emission. Upon complex formation, the optical band gap of the host La2O3 falls to the semiconductor range, from 5.1 eV to 2.5 eV. White light emission from La2O3: Clitoria ternatea complex is studied for different extract concentrations and heating conditions, and deemed as a potential replacement for conventional rare-earth doping.

Experimental and numerical investigations into cold flow characteristics of multiple micro-mixing jets for hydrogen-rich gas turbines

To explore the flow field of micro-mixing jets, cold flow characteristics of a model Micromix burner were investigated by particle image velocimetry (PIV) system and Large-eddy simulation (LES) model. Results show that LES results are in good agreement with experimental results. In the flow field of multiple micro-mixing jets, the jet velocities of nozzles farther away from the burner center have a high increase and decay rate. When the outlet Reynolds number increases, the Reynolds stress increases first and then decreases in the merging region indicating that the velocity fluctuation disappears in the second jet half, but it has little effect on the flow field structure. Comparing the flow fields of round multiple micro-mixing jets, the merging point and combined point in the elliptical jets flow field move backward. Moreover, the maximum velocity for elliptical jets is also faster than the round jets, which is caused by the high turbulent kinetic energy in the elliptical jet flow field. When the tube spacing increases from 2 to 3 times the tube diameter, positions of the two feature points change linearly. Further, the surrounding jets can decrease the velocity attenuation of the center nozzle and elongate the axial length of the two feature regions.

Time-Dependent Aftershock Probabilistic Forecasting and Ensemble Model Implementation: Insights from the 2021 Ms 7.4 Maduo Earthquake

Abstract On 22 May 2021, an Ms 7.4 earthquake with a focal depth of 17 km struck the Maduo region of Qinghai province, breaking a 3.8-year quiescence of strong earthquakes (magnitude >7.0) in mainland China. This event has increased stress on the Maqin–Maqu segment of the Kunlunshan fault, heightening the potential for a large earthquake in the region. In this study, we employed the epidemic-type aftershock sequence (ETAS) model and Reasenberg–Jones (R–J) model to fit the aftershock sequence following the mainshock, analyzing the temporal response and its ability to influence future generations. Concurrently, ensemble models were explored to leverage the strengths of both the ETAS and R–J models. Short-term forecasts of the probability and occurrence rate of aftershock events with varying magnitudes were conducted for the next three days. Then statistical methods, that is, receiver-operating characteristic diagrams and information gain, were used to evaluate the unconditional and relative performance. Our findings include that the ETAS model indicates a high decay rate with many aftershocks triggered by previous events, whereas the R–J model shows a normal decay rate with a higher proportion of strong aftershocks. The ETAS and R–J models perform better than random guesses for different aftershock magnitudes, but the ETAS model is somewhat affected by the problem of missing small earthquakes for a short period of time after the mainshock. The ensemble model that chooses the minimum strategy shows promise, especially in the early period, suggesting a reasonable and cautious decision approach should be chosen during the unstable stage. This study highlights the importance of short-term aftershock probability estimation for seismic research and decision-making. In the absence of more accurate models, current analytical approaches within the operational earthquake forecasting framework remain valuable. Continuous testing, feedback, and refinement of forecasting models, along with the development of ensemble models, are essential for enhancing seismic risk assessment and mitigation strategies.

Local factors drive leaf breakdown in tropical streams

Plants of riparian forests provide abundant dead leaves for freshwater stream ecosystems which support detritus-based food webs. The increased replacement from natural riparian forests to Eucalyptus plantations, an exotic species distributed throughout the neotropic landscapes, alters leaf breakdown as a key ecosystem process. We evaluate the breakdown of native and exotic leaf species with distinct physical and chemical characteristics (traits) in two different tropical reference condition streams located in Cerrado and Atlantic Forest biomes. We tested the hypothesis that regardless of the leaves’ origin (native or non-native species), leaf litter with higher nutrients and less recalcitrant compounds has higher decay rates. Eucalyptus camaldulensis leaf breakdown was faster than the native species Miconia chartacea in both streams. Leaf breakdown was driven by local characteristics (context dependent) and the macrodecomposer community, with more intensity to the litter's intrinsic physical and chemical quality. The higher leaf breakdown of E. camaldulensis was evidenced in the Atlantic Forest stream, that with the most increased water flow, further accelerating the leaf breakdown. Our findings indicate that due to the innate physical and chemical characteristics of E. camaldulensis, its decomposition occurs at a faster rate compared to native tropical species, as evidenced by the stream flows.

Impact of spatially varying rock disturbance on rock slope stability

Degradation of rock mass produced by rock blasting, stress relief, and other causes is an important factor in the assessment of rock strength. Quantified as a disturbance factor, such degradation varies depending on blasting control, stress state and stress relief, and rock mass quality. This study focuses on the impact of disturbance on the safety of slopes. The disturbance in the rock mass is characterized by the geometry of the disturbed zone, its size, the magnitude, and the decaying rate with the distance away from the slope surface. A method accounting for decay of rock disturbance is presented. A study of the impact of rock disturbance characteristics on the quantitative stability measures of slopes was carried out. These characteristics included disturbed zone geometry, its thickness, the maximum magnitude of the disturbance factor, and the rate of disturbance decaying. The thickness of the disturbed zone and the maximum factor of disturbance were found to have the greatest impact. For example, the factor of safety for a 45° slope in low-quality rock mass can decrease from 1.96 to 1.09 as the thickness of the disturbed zone increases from 1/4 of slope height H to the double of H and the maximum disturbance factor increases from 0.5 to 1. Uniform thickness of a disturbed zone was found to yield more conservative outcomes than the triangular zones did. The critical failure surfaces were found to be shallow for high rates of disturbance decay, and they were the deepest for spatially uniform disturbance factors.

Interplay of kernel shape and surface structure for NIR luminescence in atomically precise gold nanorods

It is challenging to attain strong near-infrared (NIR) emissive gold nanoclusters. Here we show a rod-shaped cluster with the composition of [Au28(p-MBT)14(Hdppa)3](SO3CF3)2 (1 for short, Hdppa is N,N-bis(diphenylphosphino)amine, p-MBT is 4-methylbenzenethiolate) has been synthesized. Single crystal X-ray structural analysis reveals that it has a rod-like face-centered cubic (fcc) Au22 kernel built from two interpenetrating bicapped cuboctahedral Au15 units. 1 features NIR luminescence with an emission maximum at 920 nm, and the photoluminescence quantum yield (PLQY) is 12%, which is 30-fold of [Au21(m-MBT)12(Hdppa)2]SO3CF3 (2, m-MBT is 3-methylbenzenethiolate) with a similar composition and 60-fold of Au30S(S‑t‑Bu)18 with a similar structure. time-dependent DFT(TDDFT)calculations reveal that the luminescence of 1 is associated with the Au22 kernel. The small Stokes shift of 1 indicates that it has a very small excited state structural distortion, leading to high radiative decay rate (kr) probability. The emission of cluster 1 is a mixture of phosphorescence and thermally activated delayed fluorescence(TADF), and the enhancement of the NIR emission is mainly due to the promotion of kr rather than the inhibition of knr. This work demonstrates that the metal kernel and the surface structure are both very important for cluster-based NIR luminescence materials.

Stability Analysis of the Secondary Motion of a Textured Piston

Piston–cylinder pairs are very common in industrial mechanisms. While a piston is primarily designed for axial reciprocating motion, the occurrence of secondary motions—lateral and rotational—due to the small clearance between the piston and the cylinder may lead to frictional contact, energy loss, wear and an increase in unwanted leakage. This study focuses on mitigating the secondary motion of a ringless piston. The influence of a Rayleigh step bearing and partial surface texturing with numerous micro-dimples on the dynamic stability of the secondary motion is studied. A linear model was used to obtain the trajectory of the secondary motion and Floquet theory was applied to analyze the stability and draw stability maps. The influence of various texturing and step parameters, including the dimple area density and aspect ratio for partial texturing, as well as the length and depth of treatment for both partial texturing and step profiles, on the stability of the secondary motion was examined. The normalization method is presented, enabling the expansion of the results for various operating conditions and geometries. Conclusions and guidelines regarding the optimal parameters, in terms of a wider stability range and higher decay rate, are formulated.

INDEKS KESEHATAN GIGI SISWA TAMAN KANAK-KANAK DI KELURAHAN MERGOSONO, MALANG

Dental and oral health, especially for children, is often considered a trivial matter. In fact, a healthy oral cavity condition at an early age will support the health of the oral cavity as an adult. The high rate of tooth decay in children should be a concern for parents, teachers and medical personnel. When complex dental and oral abnormalities occur in children, medical treatment causes trauma to their psychological condition, so it is much easier to prevent tooth decay through efforts to improve dental and oral health from an early age. Based on the results of dental and oral screening conducted on kindergarten children in Mergosono, Malang, it was found that the def-t score in children aged 4 years old is in the criteria of high (4,5), 5 years old is very high (7,7) and 6 years old is very high (6,8). The cause of the high incidence of dental caries in kindergarten children is the lack of knowledge about oral health, which can be concluded from the wrong behavior or way of brushing their teeth and the right knowledge about when to brush their teeth. Efforts that can be made to improve this behavior are education which is included in promotive and preventive efforts.

“Tan's Dent-Card Qr Model Website Based” as an Effort to Improve Teeth Brushing Behavior and Dental Hygiene Status Primary School Children

Background: Children aged 10-12 years have a very high rate of tooth decay at 57.6% with a mean (DMF-T) of 4.8. This is caused by one of the influencing factors, namely the low level of behavior in maintaining dental hygiene, as evidenced by the results of the 2019 Semarang City health data, that 86.7% of elementary school children do not have good tooth brushing behavior. The achievement of the new joint tooth brushing program is 47.8%, so innovation is needed in changing tooth brushing behavior, namely through the "Tan's Dent-Card QR Website Based Model" which is expected to improve tooth brushing behavior and the dental hygiene status of elementary school children. Research purposes:Producing a "Website Based Tan's Dent-Card QR Model" that is effective and feasible to implement to improve tooth brushing behavior and the dental hygiene status of elementary school children. Method : The method used in this research is Research and Development (R&D) with 5 research stages, namely needs identification, design and build, expert validation, feasibility test 1, and feasibility test 2. This research uses a pre-experimental design with a one- group pre-post- test. The sampling technique was purposive sampling consisting of 30 elementary school children aged 10-12 years who were given intervention for 14 days. Results: The validity results of the "Tan's Dent-Card QR Website-Based Model" show a value of p=0.000, which means this model is suitable for use to improve the behavior and dental hygiene status of elementary school children. “Tan's Dent-Card QR Website-Based Model” was also effective in enhancing tooth brushing behavior and dental hygiene status (p=0.000). In feasibility test 2, the result was p=0.000, which means the model is suitable for independent use by elementary school children aged 10-12 years. Conclusion: "Tan's Dent- Card QR Website-Based Model" is effective and ideal for use as an effort to improve tooth brushing behavior and the dental hygiene status of elementary school children.

Late Quaternary tectonic uplift and Yellow River evolution create high arsenic aquifers in the Hetao Basin, China

High arsenic (As) groundwater is a global problem primarily originating from As-enriched sediments. The provenance (source) and release mechanisms (sinks) of high As sediment have been identified, but the source-sink transfer is poorly understood, especially the influence of geological and surface processes. In this study, we explore the roles of tectonic movement and Yellow River evolution in provenance formation processes and evaluate the combined effects of provenance and sediment age on the As content of aquifer sediments in the northern Hetao Basin of Inner Mongolia. Based on optically stimulated luminescence (OSL) and 14C dating and detrital zircon U-Pb, As content, and lithological analyses of a 400 m core, we reconstructed As changes over the last 160 ka. Our results show clay deposited in a paleo-lake during the Gonghe movement period in the late Pleistocene (∼100 ka B.P.) is enriched in As (31.8 μg/g) due to significant provenance contributions of the As-bearing Langshan Group under tectonic uplift and mountain erosion. In contrast, clay deposited in the middle Pleistocene (∼160 ka B.P.) has lower As content (7.3 μg/g) due to the Yellow River as the primary provenance. Accordingly, the provenance of basin As forced by tectonic uplift and Yellow River evolution determines the background As of aquifer sediments. After deposition, sediment As content decays over time, with higher decay rates in coarse-grained sands than fine-grained. Overall, both provenance formation and sediment age, representing initial and dynamic states of solid phase As, jointly determine the As content of aquifer sediments. More solid phase As provided by younger sediments from the proximal orogenic provenance and reducing conditions due to frequent river–lake transitions, jointly lead to higher As concentrations in shallow groundwater. The study highlights the potential for using a combined analysis of the tectonic movement-surface processes-environment system to improve understanding of geogenic high As groundwater over global large sedimentary basins in the proximity of young orogenic belts.

Photochemical reactivity of dissolved organic carbon in subarctic lakes along a color gradient

ABSTRACT Lake–atmosphere carbon exchanges can be significantly affected by photochemical dissolved organic matter (DOM) mineralization. However, our understanding of how increasing allochthonous organic carbon input affects the photoreactivity of DOM per unit of absorbed incoming light is incomplete. Here, we measured the absorption of ultraviolet (UV) light and subsequent photochemical DOM decay in 148 lakes within the subarctic region of Abisko, Sweden. These lakes range from brown-water lakes with allochthonous input from mires to tundra clear-water lakes with relatively more autochthonous input. We used fluorescence excitation–emission matrix analysis to assess the DOM chemical composition to determine how increasing colored DOM (CDOM) affects photomineralization. We found that the photo decay rates in absolute values were positively correlated to CDOM. However, the photo decay per unit of absorbed light energy did not increase with increasing CDOM; rather, it showed a weak decreasing trend. Fluorescence analyses helped explain these patterns; humic-like fluorescent DOM, presumably of terrestrial origin, was associated with high absolute photo decay rates, but not generally with higher photoreactivity per unit of absorbed light energy than other types of DOM. The results suggest that even though increasing inputs of terrestrial substances lead to a higher abundance of photodegradable materials, CO2 emissions do not necessarily increase in lakes where browning limits the ability of light to penetrate deeper water.

Formulation and Evaluation of Immediate Release Tablets of Antimalarial Drug Hydroxychloroquine

The goal of the study was to develop and evaluate an immediate-release antimalarial tablet formulation for the effective management of malaria, an antimalarial drug as an active pharmaceutical ingredient using excipients. Appropriate pharmaceutical products and evaluate their properties in relation to the innovative product. The study was to develop an antimalarial formulation with in-vitro solubility properties equivalent to or better than the improved formulation. Therefore, an orally administered immediate-release tablet with a robust and reproducible formulation technique was developed. According to the study, the number of F3 definitions decreased the most and F8 had the most important medicinal properties. At 20 minutes, F4 appeared to lead the first high decay rate (98. 56%), followed closely by F5 (93.48%). The expansion of F1, F2 and F3 shows high decay rates at this time. Based on this information, one can analyze and compare the decay profiles of unmistakable definitions. Things such as composition, excipients used, and manufacturing geometry can influence degradation behavior, and this information may be necessary to optimize concentrations of substances of interest for drug delivery. It is then concluded that the definition number F5 may be an optimized detail.

Effective donor and acceptor modifications of carbazole-benzonitrile thermally activated delayed fluorescence molecules enabling high-performance OLEDs

Carbazole-benzonitrile derivatives (CzBNs) have great potential to enable thermally activated delayed fluorescence (TADF) molecules with both high efficiency and good stability simultaneously. However, the device performances of most CzBN-based organic light-emitting diodes (OLEDs) still lag behind other types of TADF molecules. In this work, we proposed a design strategy to construct efficient CzBN-TADF molecules through acceptor and donor modifications. The cyano-modified acceptor enables the extension of the lowest unoccupied molecular orbital while mostly preserving the overlapped area with the highest occupied molecular orbital. The optimized distributions of frontier molecular orbitals contribute to tiny singlet-triplet energy gaps while maintaining a high radiative decay rate. The incorporation of tert-butyl units in the donor groups further enhances the TADF property of resulted tPCNBN molecule due to suppressed non-radiative decay and reduced exciton self-quenching. Accordingly, OLEDs based on tPCNBN present the best device performances, such as a maximum external quantum efficiency of 33.1 % at 400 cd m−2, which is still as high as 26.3 % at a high luminance of 4000 cd m−2, demonstrating relatively low efficiency roll-off. These results confirm the effectiveness of the proposed design strategy in developing efficient and stable CzBN-TADF materials and devices.

Enhancing Light-Emitting Efficiency of Blue Through-Space Charge Transfer Emitters via Fixing Configuration Induced by Intramolecular Hydrogen Bonding.

Closely aligned configuration of the donor (D) and acceptor (A) is crucial for the light-emitting efficiency of thermally activated delayed fluorescence (TADF) materials with through-space charge transfer (TSCT) characteristics. However, precisely controlling the D-A distance of blue TSCT-TADF emitters is still challenging. Herein, an extra donor (D*) located on the side of the primary donor (D) is introduced to construct the hydrogen bonding with A and thus modulate the distance of D and A units to prepare high-efficiency blue TSCT emitters. The obtained "V"-shaped TSCT emitter presents a minimal D-A distance of 2.890 Å with a highly parallel D-A configuration. As a result, a high rate of radiative decay (>107 s-1) and photoluminescence quantum yield (nearly 90%) are achieved. The corresponding blue organic light-emitting diodes show maximum external quantum efficiencies (EQEmax) of 27.9% with a Commission Internationale de L'Eclairage (CIE) coordinate of (0.16, 0.21), which is the highest device efficiency of fluorene-based blue TSCT-TADF emitters. In addition, the TSCT-TADF emitter-sensitized OLEDs also achieve a high EQEmax of 29.3% with a CIE coordinate of (0.12, 0.16) and a narrow emission.

Dissipation-Induced Photon Blockade in the Anti-Jaynes–Cummings Model

Due to the fundamental differences between the quantum world and the classical world, some phenomena, such as entanglement and wave–particle duality, only exist in the quantum realm. These peculiar phenomena cannot be demonstrated by classical means: Quantum networks, quantum cryptography, and quantum precision measurements all require quantum sources. Photons are particularly well-suited as quantum sources owing to their minimal interaction with the environment, high flight speed, and ease of interaction with current typical quantum systems. Single-photon sources include pulsed excitation of quantum dots, spontaneous parametric down-conversion, and photon blockade. Herein, we propose that the anti-Jaynes–Cummings model can induce a pronounced photon antibunching effect when subjected to intense cavity dissipation. Similar to the photon blockade caused by strong photon–photon interaction, this antibunching effect is referred to as ’dissipation-induced blockade’. Our findings indicate that the minimum decay rate of a qubit, coupled with a high decay rate for photons, is conducive to achieving strong antibunching within the system. Notably, g(2)(0)<g(2)(τ), a characteristic of photon antibunching, is only valid under the optimal condition Δ=0. Conversely, g(2)(0)<1 is satisfied across all parameters, indicating that g(2)(0)<1 is not a prerequisite for antibunching in the anti-Jaynes–Cummings model. Moreover, under the optimal conditions of the antibunching effect, the average photon number attains its peak value. Consequently, the current anti-Jaynes–Cummings model is promising for developing single-photon sources characterized by excellent purity and average photon number.

Topological Photonic Crystal in Microwave Region Based on Coupled Superconducting Resonators

Topological photonics has been widely investigated due to its profound physical significance and great number of potential applications. Microwaves have long wavelengths, so it is relatively easy to manufacture large-sized microwave photonic crystals, enabling researchers to observe and measure phenomena such as topological boundary states. Nevertheless, the quality factors (QFs) of most resonators composed of traditional materials in the microwave region are relatively low, leading to topological edge states with high decay rates. In this study, we present a one-dimensional topological photonic crystal in the microwave region based on coupled superconducting resonators. A topological state with a QF as high as 6000 is observed, which proves this to be a new platform for the investigation of topological photonics with low decay rates in the microwave regime.

Influence of the correlations in an active medium on the pump-induced exceptional points and strong coupling

Exceptional points show great prospects for applications such as imaging, sensing, and designing lasers. Recently, systems with amplifying active medium exhibiting pump-induced exceptional points have attracted much attention due to the possibility of controlling the strong coupling between light and matter with the aid of pumping. In such structures, the interaction of the active molecules with external degrees of freedom, such as phonons or impurities, leads to the destruction of the correlations between the polarizations of different molecules. We study the effect of the correlation decay on system behavior near a pump-induced exceptional point. We show that exceptional points and strong coupling are robust to correlation decay and disappear only at very high rates of correlation decay, much larger than other relaxation rates. The obtained result is crucial for designing systems with exceptional points and strong coupling.

Quality prediction of kiwifruit based on transfer learning

Kiwifruit has a high decay rate, in part because quality changes during storage cannot be easily monitored in real time. In order to better monitor the shelf life of kiwifruit and understand the quality changing process during storage, internal quality indexes such as hardness, respiratory intensity and TSS(Total Soluble Solid) were considered into the prediction models. The prediction models were constructed based on BPNN (Back Propagation Neural Network), Random Forest (RF) and XGBoost (eXtreme Gradient Boosting) respectively. And transfer learning algorithm was used to construct the quality prediction models with BPNN, RF, and XGBoost algorithms as the base learner. In the experiments, sample data were augmented by adding Gaussian noise, which effectively prevented the model from over-fitting. The experimental results showed that the prediction accuracy of each index based on transfer learning was better than that of individual BPNN, RF and XGBoost. Moreover, the average prediction accuracy of the models based on transfer learning was 96.2%, and that of respiratory intensity was as high as 99.4%. Therefore transfer learning can be used to effectively analyze and predict changes of kiwifruit quality indexes during storage.

Unique continuation problem on RCD Spaces. I

In this note we establish the weak unique continuation theorem for caloric functions on compact RCD(K, 2) spaces and show that there exists an RCD(K, 4) space on which there exist non-trivial eigenfunctions of the Laplacian and non-stationary solutions of the heat equation which vanish up to infinite order at one point . We also establish frequency estimates for eigenfunctions and caloric functions on the metric horn. In particular, this gives a strong unique continuation type result on the metric horn for harmonic functions with a high rate of decay at the horn tip, where it is known that the standard strong unique continuation property fails.

Large wood recruitment, retention and mobilization in low-order streams of the Brazilian Savanna

The delivery of wood to streams varies in space and time and may occur continuously or episodically. Once in a stream, wood may be retained or transported due to the balance between driving (water flow) and resisting forces (channel features and wood characteristics). Despite there being few studies directly measuring wood mobility, notable variations in annual transport rates and mean travelled distances have already been detected worldwide. In the tropics, due to wetter and warmer conditions and consequently higher decay rates and peak discharge, wood is believed that more readily degraded and transported downstream. However, there exists a knowledge gap regarding wood dynamics in tropical streams and even more considering tropical non-forested environments. In the present study, we aimed to document large wood (LW) recruitment, retention, and mobilization over a period of one year in eight low-order streams of the Cerrado (the South American Savanna) by tagging and tracing LW pieces. We detected high LW transport and recruitment rates in Cerrado streams, such that the total wood amounts remained constant over time. However, there were important differences between streams due to their distinct channel morphologies and the occurrence of episodic events. The LW length and diameter, original location and orientation were the most important factors in the prediction of the LW travelled distance, which ranged from zero to almost 100 m in one year. Our findings provide unprecedented information regarding wood mobility in tropical savanna streams in South America. To further advance knowledge about the dynamics of wood in Cerrado streams, future studies should characterize the great diversity of wood, especially with regard to densities that may strongly affect wood mobility. Furthermore, it is essential to perform long-term studies to document the dynamics of wood over years in these environments.