Tendency To Shift Research Articles

33S NMR: Recent Advances and Applications.

The purpose of this review is to present advances and applications of 33S NMR, which is an underutilized NMR spectroscopy. Experimental NMR aspects in solution, chemical shift tendencies, and quadrupolar relaxation parameters will be briefly summarized. Emphasis will be given to advances and applications in the emerging fields of solid-state and DFT computations of 33S NMR parameters. The majority of the examples were taken from the last twenty years and were selected on the basis of their importance to provide structural, electronic, and dynamic information that is difficult to obtain by other techniques.

Enhancing Layer-Engineered Interlayer Exciton Emission and Valley Polarization in van der Waals Heterostructures via Strain.

Layer-engineered interlayer excitons from heterostructures of transition-metal dichalcogenides (TMDCs) exhibit a rich variety of emissive states and intriguing valley spin-selection rules, the effective modulation of which is crucial for excitonic physics and related device applications. Strain or high pressure provides the possibility to tune the energy of the interlayer excitons; however, the reported emission intensity is substantially quenched, which greatly limits their practical application in optoelectronic devices. Here, via applying uniaxial strain based on polyvinyl alcohol (PVA) encapsulation technique, we report enhanced layer-engineered interlayer exciton emission intensity with largely modulated emission energy in WSe2/WS2 heterobilayer and heterotrilayer. Both momentum-direct and momentum-indirect interlayer excitons were observed, and their emission energies show an opposite shift tendency upon applied strain, which agrees with our DFT calculations. We further demonstrate that intralayer and interlayer exciton states with low phonon interactions can be modulated through the mechanical strain applied to the PVA substrate at low temperatures. Due to strain-induced breaking of the 3-fold rotational symmetry, we observe the enhanced valley polarization of interlayer excitons. Our study contributes to the understanding and modulation of the optical properties of interlayer excitons, which could be exploited for optoelectronic device applications.

Changes in park visits and the shift towards rural recreation: Evidence from the COVID-19 pandemic in the UK

The spread of COVID-19 and corresponding government interventions have changed residents’ travel and mobility, and recent academic literatures suggests that this have had a positive impact on rural recreation. This study analyzed the impact of the COVID-19 pandemic on rural recreation from the perspective of population mobility, aiming to explore the changes in park visits during the pandemic, identify the motivation and demand of urban residents for leisure activities under the impact of the pandemic and to test the hypothesis of the accelerating the shift to rural recreation. Using the UK as the case study, it compared the park visits in four stages according to the COVID-19 policies: pre-, strict, eased, and fully lifted lockdown. Based on multivariate datasets, stepwise regression models of park visits in urban areas of 25 counties in the UK during each stage were constructed and compared. The results showed that residents preferred to visit smaller parks before and in the early stage of the pandemic. In the strict lockdown stage, the movement of residents to parks decreased significantly. During the eased lockdown period, park visits increased significantly, but there was clear spatial variation across the country attributed to the severity of the pandemic in each region, and different control policies of local governments. During the period when the lockdown was fully lifted, the frequency of park visits remained an increasing trend compared to the baseline period but decreased slightly compared to the eased lockdown period due to the increasing number of park visitors and more crowded park sites. Obviously, residents were more willing to visit distant country parks after an extended period of lockdown control, and mainly congregated in dispersed recreation sites such as the wilderness and forests that were distributed outside of urban areas and farther away. This study broadens the related literature using the evidence from changes of park visits, which to some extent confirms that the pandemic accelerates the leisure activities taking place from urban to suburban parks. The results can provide new inspiration for the future research on rural recreation and tourism, and also provide guidelines for planning peri-urban rural parks to prepare for future public health crises along with the population shift tendency.

Modelling analysis embodies drastic transition among global potential natural vegetations in face of changing climate

Potential natural vegetation (PNV) is a valuable reference for ecosystem renovation and has garnered increasing attention worldwide. However, there is limited knowledge on the spatio-temporal distributions, transitional processes, and underlying mechanisms of global natural vegetation, particularly in the case of ongoing climate warming. In this study, we visualize the spatio-temporal pattern and inter-transition procedure of global PNV, analyse the shifting distances and directions of global PNV under the influence of climatic disturbance, and explore the mechanisms of global PNV in response to temperature and precipitation fluctuations. To achieve this, we utilize meteorological data, mainly temperature and precipitation, from six phases: the Last Inter-Glacial (LIG), the Last Glacial Maximum (LGM), the Mid Holocene (MH), the Present Day (PD), 2030 (2021–2040) and 2090 (2081–2100), and employ a widely-accepted comprehensive and sequential classification system (CSCS) for global PNV classification. We find that the spatial patterns of five PNV groups (forest, shrubland, savanna, grassland and tundra) generally align with their respective ecotopes, although their distributions have shifted due to fluctuating temperature and precipitation. Notably, we observe an unexpected transition between tundra and savanna despite their geographical distance. The shifts in distance and direction of five PNV groups are mainly driven by temperature and precipitation, although there is heterogeneity among these shifts for each group. Indeed, the heterogeneity observed among different global PNV groups suggests that they may possess varying capacities to adjust to and withstand the impacts of changing climate. The spatio-temporal distributions, mutual transitions and shift tendencies of global PNV and its underlying mechanism in face of changing climate, as revealed in this study, can significantly contribute to the development of strategies for mitigating warming and promoting re-vegetation in degraded regions worldwide.

Model for Predicting Lateral Shifts and Driving Style of Motorized Two-Wheelers

The compact sizes, lack of available physical protection, and complex maneuvering patterns of motorized two-wheeler (MTW) riders make them more vulnerable to crash risks and accidents. Considering the increased vulnerability of MTWs in dense urban mixed traffic environments, a proper evaluation and modeling of their lateral movement decisions and driving style can enhance safety associated with the riders and augment the reliability of the existing microsimulation models. Utilizing trajectory data of a six-lane divided urban arterial, the current study attempts to investigate the lateral movement (lateral shift) tendency of MTWs, addressing different influential variables that may affect riders’ decisions and describing how this choice is affected by prevailing traffic conditions. Based on several driving style parameters, such as change in speed, change in angular position, and longitudinal gap maintained with rear vehicles, this study further contributes to the existing literature by proposing a new index for identifying the driving style of riders during the lateral shifting process. Modeling results of a multinomial logit model indicated the importance of considering longitudinal and lateral gaps, vehicle speeds, and lateral fluctuations made by the subject MTW in the past trajectories in modeling the lateral shift decisions of riders. Considering the number of lateral fluctuations as an indicator of MTWs’ driving style, a new “aggressiveness index” is defined and, accordingly, a modeling approach is proposed to classify aggressive and non-aggressive driving styles of the riders. The results suggest that the history of past trajectories of the subject MTW during lateral shifting should be considered, and consideration of a non-linear relationship among the parameters can result in a better classification of driving style of MTW riders.

Multinuclear Pd(II) oligomeric nanohoop complexes with 2,2′‐bipyridyl‐embedded cycloparaphenylenes ligands exhibiting ultrahigh third‐order nonlinear optical performance

AbstractUnlike traditionally available linear frameworks, cyclic transition‐metal architectures with cycloparaphenylenes (CPPs) ligands provide new access to develop modern nonlinear optical (NLO) materials. In this work, a sequence of “staircase” Pd(II) oligomeric nanohoop complexes with the 2,2′‐bipyridyl‐embedded CPPs ligand unit through “series connection” mode and “Ω‐type” Pd(II) trimeric isomer have been systematically designed and investigated via density functional theory. Herein, we first report the dependence of third‐order NLO responses on the number of bipyridine CPP building ligands in a quantitative way. Impressively, the Pd(II) trimeric complexes possess ultrahigh third‐order NLO responses, which are ascribed to the large orbital delocalization and decreased energy gap. To our delight, the enlargement of the nanohoop size is beneficial to improving third‐order NLO responses for Pd(II) oligomeric nanohoop complexes, and the maximum absorption spikes show the blue shift tendency. The effect of size on the third‐order NLO responses becomes much larger with the addition of bipyridine CPPs ligand. Overall, we hope the current work will deliver a new quantitative structure–property relationship toward the design and synthesis of Pd(II) oligomeric nanohoop complexes with high third‐order NLO responses.

Probing a Neural Network Model of Sound Change for Perceptual Integration

The cross-linguistic tendency for contrast shifts to occur between some cues more than others has been investigated typologically and experimentally (Yang 2019), but with less attention in computational modeling. This paper adapts a human experimental paradigm (Kingston et al. 2008) to the speech perception component of a neural network model of sound change (Beguš 2020) to better understand how it processes acoustic cues in the context of Yang’s proposal that auditory dimensions affect which cues are more likely to undergo contrast shift. Piloting this neural network probing technique, I find evidence that the model integrates different pairs of English stop voicing cues than humans do, suggesting that further amendments to the model are necessary to implement Yang (2019)’s account. In general, these results highlight potential acoustic processing differences between humans and the model under investigation, a Convolutional Neural Network, which is commonly used in spoken language applications.

Comparison of Intraocular Lens Power Calculation formulas with and without Total Keratometry and Ray tracing in patients with previous myopic SMILE.

This study evaluated the prediction error (PE) variance and absolute median PE of different IOL calculation formulae including last generation formulae such as Barrett True-K with K, Okulix and Total Keratometry (TK) based calculations with Haigis and Barrett True-K in a simulation model in post-SMILE eyes. Department of Ophthalmology, University Hospital Marburg, Germany. Design: Prospective study. Preoperative measurements included IOL power calculation before and after SMILE surgery. The target refraction was set to be the lowest myopic refractive error in pre-SMILE eyes. The IOL power targeting at the lowest myopic refractive error in pre-SMILE eyes was selected for the post-SMILE IOL calculation of the same eye. The difference between the predicted refraction of pre- and post-SMILE eyes with the same IOL power was defined as IOL-Difference (IOL-Diff). The refractive change induced by SMILE was defined as the difference between preoperative and postoperative manifest refraction (SMILE-Diff). 98 eyes from 49 patients underwent bilateral myopic SMILE. The PE variance of Okulix was not significantly different compared to Barrett True-K with TK (P=0.471). The standard deviation (SD) of the mean PEs were ±0.413 D (Haigis-TK), ±0.453 D (Okulix), ±0.471 D (Barrett True-K with TK), ±0.556 D (Haigis-L) and ±0.576 D (Barrett True-K with K). The mean absolute PE were 0.340 D, 0.353 D, 0.404 D, 0.511 D and 0.715 D for Haigis-TK, Okulix, Barrett True-K with TK, Barrett True-K with K and Haigis-L respectively. The highest percentage of eyes within ± 0.50 D was achieved by Okulix followed by Haigis TK, Barrett True-K with TK, Barrett True-K with K and Haigis-L. Our results suggest that Haigis in combination with TK, Okulix and Barrett True-K with and without TK offer good options for accurate IOL power calculation after SMILE. Haigis-L showed a tendency for myopic shift in eyes after previous SMILE.

From De-collectivization to Re-collectivization: New Transformation Trend in Agriculture Production in Taicang City of the Eastern China from the Perspective of 'Governmentality'.

The continuous development of agricultural technologies and produces trade and updated state reforms strongly shape the dominant organizing styles of local agriculture production. Since the end of the 1970s, rural China has witnessed a drastic agriculture transformation featured by de-collectivization, and recently in Taicang, a developed city in the eastern China, a kind of new cooperative farms have replaced the smallholders by pooling households' contracted farmland, signaling a new shift tendency towards agriculture recollectivization that is distinctive compared to other countries. Given the state governance's leadership in promoting this latest transformation, drawing on the theoretical concept of 'governmentality' that is powerful in understanding how to govern the society to meet certain objectives, this paper examines the accurate processes of agriculture re-collectivization in Taicang City based on the methods of semi-structured interview and participant observation. Our research shows that the China's tax-sharing and relevant reforms in the 1990s framed a new governance structure in line with the new mode of 'governmentality' closely linked to 'advanced liberalism', creating the responsibility shift from central to local governments and a set of evaluation technologies, and guiding various actors to engage in the agriculture re-collectivization practice in Taicang. Importantly, the considerable subsidies and the impressive extension services in terms of farming personnel training and agricultural techniques diffusion underpin the normal running of cooperative farms and contribute to the local implementation of national strategy of agriculture modernization. We argue that the combination of distinctive institutional arrangement of rural land owned by village collectives in China and the burgeoning local economy allows the developed areas to re-collectivizing the agriculture production for ensuring grain self-sufficiency rather than capturing more share in global agriculture products trade, and that the cooperative farms in our case have been deeply integrated into the 'modern procurement system' and become more sensitive to market fluctuation, requiring rural extension service to transform towards farms' capacity building for maintaining the long-term development momentum.

Reproducing experiential meaning in translation: A systemic functional linguistics analysis on translating ancient Chinese poetry and prose in political texts.

Ancient Chinese poetry and prose (ACPP) are the essence of traditional Chinese culture and also literary gems of the world. Despite the long tradition of previous Chinese Presidents using ACPP in their political addresses, the translation work on the three volumes of Xi Jinping: The Governance of China with much ACPP still poses a daunting challenge to the translation of literary texts in non-literary texts. As experiential meaning is inherent in all kinds of texts, literature, and non-literature, this study, drawing on the sights of Halliday's experiential mode of meaning and register theory in Systemic Functional Linguistics (SFL), explored how the ACPP's experiential meaning was rendered in the political texts, and factors motivating transitivity patterns and shift tendencies. Statistics showed that the translations tend to reproduce the experiential meaning such that it involves more representations of the flow of events and the creation of relationships among entities, focusing more on construing the experience of the physical world rather than personal emotions, feelings, or cognition. Besides, the target text is also inclined to simplify the experiential meaning by compressing and omitting unnecessary transitivity processes and the participant and circumstance nominalization. This research found that the factors responsible for such tendencies include the features of political texts, language differences, the distribution of process types, the delicacy of the transitivity system, and register variations of fields of activity. With these findings, the study is expected to contribute to the SFL approach of studying literary translation in non-literary texts through the prism of experiential meaning and offer guidance in the translation of political literature with ACPP.

Exploration of Sulfur-Containing Nanoparticles: Synthesis, Microstructure Analysis, and Sensing Potential.

In this work, three different sulfur sources such as sulfur powder, sodium sulfide, and sodium thiosulfate are selected to prepare sulfur-derived quantum dots (S-QDs), Na2S-derived nanoparticles (NS-NPs), and Na2S2O3--derived QDs (NSO-QDs) in the presence of NaOH or assisted by hydrogen peroxide etching. The low sulfur percentage in the above three samples and the synthesis experiments in the presence of nitrogen/oxygen all support that poly(ethylene glycol) (PEG) plays an important role during the assembly process and the definition of sulfur dots is not accurate. For photophysical features, remarkable green quantum dots (S-QDs) possess an excitation-independent emission peak at 500 nm. But NS-NPs and NSO-QDs demonstrate observable shift tendency, and the evolution of emission profiles varies from 480 to 586 nm. NSO-QDs can be used as a fluorescent probe for highly selective and quantitative detection of Ni2+ in an aqueous solution in the presence of potential interfering ions with a low detection limit (0.18 μM) and a wide linear range (8-380 μM). Their reusability performance has also been demonstrated by employing dimethylglyoxime as the restoration reagent.

Spent Graphite from End-of-Life Lithium-Ion Batteries (LIBs) as a Promising Nanoadditive to Boost Road Pavement Performance

To take swift action towards tackling the global pollution crisis of discarded lithium-ion batteries (LIBs) while reinforcing road structures, this investigation was undertaken. The influence of various proportions of spent graphite (e.g., 5, 10, and 15 wt.% SG), harvested from end-of-life LIBs, on the performance of base AP-5 asphalt cement was studied. Multiple laboratory techniques have been employed to characterize the internal physiochemical interaction between the additive and the binder. These techniques include: elemental analysis (EA), thin-layer chromatography-flame ionization detection (TLC-FID), Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), empirical test methods (e.g., penetration, softening point, viscosity, and ductility), dynamic shear rheometer (DSR), and multiple stress-creep recovery (MSCR). Prior to aging, SARA analysis demonstrated that the incremental SG addition into the AP-5 bitumen reduced the contents of saturates, aromatics, and resins, and increased the proportion of asphaltenes. After aging, the saturated and aromatic hydrocarbons kept decreasing; however, the resins increased and the asphaltenes declined. Accordingly, this has brought a progressive shift tendency in the stable–colloidal system for all binders from sol-state towards sol-gel-state. FT-IR scan revealed that the SG has no apparent chemical interaction with the binder, and is endowed solely with filling effects. XRD diagnosis highlighted that the steady SG incorporation into the binder amplified its crystallinity; thereby boosting the thermomechanical properties of mastics. SEM imaging unveiled that the lower-dose of SG exhibited higher compatibility within the bitumen matrix; nevertheless, the intermediate/higher-doses made the binder body relatively rougher. DSR/MSCR/conventional tests indicated that when the asphalt is blended with the graphitic powder under unaged/aged conditions, it becomes stiffer, more viscous, and less cohesive; thereby rendering it more resistant to deformation but not to cracking. In summary, it is promisingly proven that the SG could be successfully used as an asphalt additive and could be beneficial for improving paving performance and mitigating the pollution caused by dead LIBs as well.

GOLD PRICESFORECASTING USING TRIPLE EXPONENTIAL METHOD

Governments, organizations, and citizens have taken an interest in gold price fluctuations. Gold price forecasting that is accurate may effectively capture price shift tendencies and reduce the effects of gold market volatility. However, due to the multi-factor and nonlinear nature of the gold market. The triple exponential smoothing strategy is used in this study to predict the rise in a value over time since it can replicate trends and seasonal patterns. according to the gold price swings pattern and seasonal components at the same time To calculate system accuracy, the Mean Absolute Percentage Error is employed (MAPE). With alpha 0.15 and beta 0.85 as parameter values, the triple exponential smoothing (TES) approach achieves an accuracy rate of 86.93 percent and a MAPE of 12.49 percent in this study.

Experimental and theoretical investigation on the inhibition performance of disulfide derivatives on cobalt corrosion in alkaline medium

Cobalt, as the barrier layer material for 14 nm copper interconnection, has been widely applied owing to its superior characteristics of low resistivity, excellent adhesion performance and blocking properties for copper. Most of the preciously developed cobalt corrosion inhibitors under weak alkaline condition are toxic, low water solubility, and limited to traditional experimental research. In this work, 3,3-dithiodipropionic acid (DDA), 2,2-dibenzamidodiphenyl disulfide (DPD) as potential corrosion inhibitors for cobalt in NH4Cl and H2O2 media under alkaline environment were investigated. Electrochemical experiments, surface morphology characterization, quantum chemical calculation and molecular dynamic simulation were combined to analyze the corrosion inhibition ability and mechanism. The experimental and theoretical results present that these disulfide derivatives can inhibit the corrosion behavior of cobalt surface effectively in ammonium-based aqueous solutions. When the concentration of inhibitors was 0.5 wt%, the corrosion inhibition efficiency of DDA, DPD reach up to 92.9%, 91.41%, respectively. Their favorable capability is attributed to the dense adsorption films following the Langmuir adsorption isotherm. Besides, these two inhibitors show excellent performance of galvanic corrosion inhibition at the Co/Cu interface, which is consistent with the shift tendency simulations for binding to Co/Cu substrates. The results of water solubility and toxicity tests indicate that DDA is more suitable for industrial applications.

Priorities for the development of investment activity in the agricultural sector of Ukraine in the context of modern European trends

Purpose. The aim of the article is the analysis of current trends in investment support of the domestic agricultural sector in the context of current European practice and justification of promising areas of investment activity in agriculture of Ukraine. Methodology of research. A set of general scientific and specific methods of economic research is used when writing the article, in particular, methods of theoretical generalizations: analysis, abstract and logical method (substantiating modern trends in investment support of the agricultural sector of Ukraine and the EU); economic and statistical methods (when assessing the dynamics of investment in the domestic agricultural sector); methods of comparison and scientific synthesis (in substantiation of priority forms and directions of development of investment activity of agriculture of Ukraine taking into account the leading experience of the European practice); methods of graphic display of the received results of researches. Findings. It is determined that the level of investment security and investment activity of the national agricultural sector, in comparison with European practice, remains low. Significant differences are also characterized by key areas of investment in agriculture in Ukraine and within the EU agricultural sector. The main tendencies of investment support of agribusiness of European countries are analysed, features of financing of investment projects and tendencies of shift of geographical structure of agrarian investments towards the countries of North Africa and Asia are revealed. Some aspects of the European policy of investment in the agricultural sector of the Ukrainian economy are analysed. The financial and geographical structure of sources of investment flows of domestic agriculture is studied. Originality. The priorities of investment activity of the agrarian sector of the national economy are combined with the key modern tendencies of investment provision of agriculture of the EU countries for realization of possibilities of search of joint investment directions and projects, and also financial instruments of their realization. Practical value. The trends and features of investment support of the agricultural sector of Ukraine in the context of modern European practice revealed as a result of research allowed to substantiate the priority areas of further development of investment activities and possible options for its financial support in the domestic agricultural sector in the near future. Key words: investment flows, investment activity, agrarian sector, agribusiness, financial provision, EU countries, strategic development.

Probing relationships between reinforcement learning and simple behavioral strategies to understand probabilistic reward learning

BackgroundReinforcement learning (RL) and win stay/lose shift model accounts of decision making are both widely used to describe how individuals learn about and interact with rewarding environments. Though mutually informative, these accounts are often conceptualized as independent processes and so the potential relationships between win stay/lose shift tendencies and RL parameters have not been explored. New methodWe introduce a methodology to directly relate RL parameters to behavioral strategy. Specifically, by calculating a truncated multivariate normal distribution of RL parameters given win stay/lose shift tendencies from simulating these tendencies across the parameter space, we maximize the normal distribution for a given set of win stay/lose shift tendencies to approximate reinforcement learning parameters. ResultsWe demonstrate novel relationships between win stay/lose shift tendencies and RL parameters that challenge conventional interpretations of lose shift as a metric of loss sensitivity. Further, we demonstrate in both simulated and empirical data that this method of parameter approximation yields reliable parameter recovery. Comparison with existing methodWe compare this method against the conventionally used maximum likelihood estimation method for parameter approximation in simulated noisy and empirical data. For simulated noisy data, we show that this method performs similarly to maximum likelihood estimation. For empirical data, however, this method provides a more reliable approximation of reinforcement learning parameters than maximum likelihood estimation. ConclusionsWe demonstrate the existence of relationships between win stay/lose shift tendencies and RL parameters and introduce a method that leverages these relationships to enable recovery of RL parameters exclusively from win stay/lose shift tendencies.

Projecting Suitability and Climate Vulnerability of Bhutanitis thaidina (Blanchard) (Lepidoptera: Papilionidae) with Conservation Implications

Bhutanitis thaidina is an endemic, rare, and protected swallowtail in China. Deforestation, habitat fragmentation, illegal commercialised capture, and exploitation of larval food plants are believed to be the four major causes of population decline of B. thaidina in the recent decade. However, little attention was paid to the impact of climate change. This study used ecological niche factor analysis and species distribution model to analyse the current suitable areas for B. thaidina with BioClim variables as well as its future suitable areas under four future climate scenarios (represented by four Representative Concentration Pathways: RCP2.6, RCP4.5, RCP6.0, and RCP8.5). Statistical analysis was carried out to compare the possible area and altitude changes to the distribution of B. thaidina under changing climate. Our analyses showed that the suitable areas for B. thaidina are fragmented under the current climate, with four suitable centres in northwestern Yunnan, northeastern Yunnan and northwestern Guizhou, the western margin of Sichuan Basin, and Qinling mountains. Apart from further habitat fragmentation under climate change, slight range expansion (average 6.0–8.9%) was detected under the RCP2.6 and RCP4.5 scenarios, while more range contraction (average 1.3–26.9%) was detected under the RCP6.0 and RCP8.5 scenarios, with the two southern suitable centres suffering most. Also, a tendency of contraction (2,500–3,500 m) and upslope shift (~600 m) in suitable altitude range were detected. The findings of this study supported the climate-vulnerable hypothesis of B. thaidina, especially under future climate like the RCP6.0 and RCP8.5 scenarios, in terms of contraction in suitable areas and altitude ranges. Conservation priority should be given to northwestern Yunnan, northeastern Yunnan, and northwestern Guizhou to alleviate the stress of massive habitat loss and extinction. Refugial areas should be established in all four suitable centres to maintain genetic diversity of B. thaidina in China.

Broadband tunable plasmonic substrate using self-assembled gold–silver alloy nanoparticles

In the present work, a facile approach of Au–Ag alloy NPs fabrication is proposed for plasmonic inclusion applicative studies. These hybrid NPs were prepared by the sequential deposition of Ag, Au layers on a glass substrate via RF-sputtering followed by high-temperature annealing. Compositional and size controllability of the NPs was attained by changing the ratio of nominal thicknesses of the respective Au, and Ag layers during the deposition. LSPR red (blue) peak shift occurs with increasing layer thickness Au (Ag) signifying the peak sensitivity. The influence of geometrical, compositional, and background media for achieving LSPR-sensitivity is examined and validated by FDTD simulation studies. With the agreeable peak shift tendencies, the proposed study of broadband tunable LSPR-sensitivity is expected to provide a framework for a wide range of plasmonic applications.

Emission color tuning and phase transition determination based on high-pressure up-conversion luminescence in YVO4: Yb3+, Er3+ nanoparticles

Compression of up-converting (UC) YVO4 nanocrystals doped with Yb3+ and Er3+ ions leads to the luminescence color tuning, which can be used for the determination of pressure-induced zircon-to-scheelite phase transition. Spherical (≈20 nm), tetragonal YVO4: Yb3+-Er3+ UC nanoparticles (NPs) were synthesized by the hydrothermal method. The high-pressure spectroscopic analysis (up to ≈11 GPa) of the material was carried out in a diamond anvil cell (DAC), in a compression-decompression run. With the increasing pressure values, the intensity of UC emission (λex= 975 nm) decreased along with shifts of the band centroids. The maximum shifts was ≈ 0.39 nm/GPa, for the 4F9/2→4I15/2 transition. Broadening of the bands and overlapping of the split Stark sub-levels were also observed. The sudden and huge change in the band ratios, and deviations from the linear shift tendency of chromaticity coordinates in the CIE diagram around ≈ 8 GPa, clearly shows the influence of phase transition on the luminescence properties of the material, under high pressure conditions.

Effect of Gate-Oxide Degradation on Electrical Parameters of Power MOSFETs

Gate oxide in power metal–oxide–semiconductor field effect transistors (MOSFETs) degrades over time. The degradation leads to an accumulation of oxide-trapped charges within the gate oxide and an accumulation of interface-trapped charges at the oxide–semiconductor surface of power MOSFETs. Overtime, such charges significantly alter the electrical parameters of power MOSFETs; to observe this, the electrical parameters are utilized as precursors of gate-oxide degradation. The purpose of this paper is threefold: 1) to propose a new online precursor of gate-oxide degradation—the gate plateau time; 2) to demonstrate a simultaneous dip-and-rebound variation pattern of four precursors of gate-oxide degradation: threshold voltage, gate plateau voltage, gate plateau time, and on-resistance; and 3) to compare the shift tendencies of each precursor over the course of gate-oxide degradation. The existing studies of gate-oxide degradation mechanisms and their effects on threshold voltage and mobility reduction were extended to correlate a variation of all four precursors using analytical expressions. The variation patterns were experimentally verified using high-electric field stressing in two different commercial power MOSFETs. The new precursor, the gate plateau time, was found to be a competitive gate-oxide degradation precursor, as it had a higher positive shift than threshold voltage and gate plateau voltage. In addition, the threshold voltage was found to be the most sensitive indicator of the negative shift (dip), while the on-resistance and gate plateau time were found to be the most sensitive indicators of the positive shift (rebound).