Bias-drift insensitive full-field frequency response characterization of a thin-film lithium niobate-based intensity modulator.

We propose a rapid and precise scheme for characterizing the full-field frequency response of a thin-film lithium niobate-based intensity modulator (TFLN-IM) via a specially designed multi-tone microwave signal. Our proposed scheme remains insensitive to the bias-drift of IM. Experimental verification is implemented with a self-packaged TFLN-IM with a 3 dB bandwidth of 30 GHz. In comparison with the vector network analyzer (VNA) characterization results, the deviation values of the amplitude-frequency response (AFR) and phase-frequency response (PFR) within the 50 GHz bandwidth are below 0.3 dB and 0.15 rad, respectively. When the bias is drifted within 90% of the Vπ range, the deviation fluctuation values of AFR and PFR are less than 0.3 dB and 0.05 rad, respectively. With the help of the full-field response results, we can pre-compensate the TFLN-IM for the 64 Gbaud PAM-4 signals under the back-to-back (B2B) transmission, achieving a received optical power (ROP) gain of 2.3 dB. The versatility of our proposed full-field response characterization scheme can extend to various optical transceivers, offering the advantage of low cost, robust operation, and flexible implementation.

Direct Work Function Measurement Using in-situ Ambient Pressure X-ray Photoemission Spectroscopy and Its Application on Copper Oxidation Process.

The work function (WF) measurement plays a critical role in engineering energy materials and energy devices. However, the ultra-high vacuum (UHV) environments of photoemission method limit the practical application for absolute work function measurements of materials, especially under complex working conditions. To understand the energy level of materials under complex chemical environments, the in-situ measurements of work function is necessary in complex metal/semiconductor system for various application. In this paper, we describe the utilization of ambient pressure X-ray photoemission spectroscopy (APXPS) with utilization of low photon energy X-ray for absolute WF measurements at BL02B of the Shanghai Synchrotron Radiation Facility. We herein present the WF measurement during oxygen adsorption on Pt(111) and oxidation of Cu(111) in ambient oxygen environment as demonstration of the APXPS capability for WF measurement. After oxygen chemisorption on Pt and formation of Cu2O, the WF will increase. This is due to charge transfer from metal to chemisorbed oxygen atoms. After the formation of bulk Cu2O and CuO, the WF value almost remain at ~5.5 eV. We believe the direct measurement of absolute work function via APXPS could help bridge the gap between the physical properties and the surface chemical species for metal/semiconductor materials.

Reciprocal longitudinal relations between self-efficacy and coping style: The explanatory mechanism of future self-continuity.

BACKGROUND: It has been demonstrated that self-efficacy and coping styles are related. However, whether there is a reciprocal longitudinal relation between self-efficacy and coping styles needs to be examined. In this longitudinal study, we tested the reciprocal impacts of self-efficacy and coping styles, taking into account the role of future self-continuity (FSC) in these effects. METHODS: The sample included 346 university students in central and southwestern China (48.3% female; Mage = 21.20). Three waves of questionnaire data were collected at half-year intervals. Cross-lagged models were adopted for data analysis. RESULTS: Self-efficacy at Waves 1 and 2 positively predicted positive coping style at Waves 2 and 3, and positive coping style at Waves 1 and 2 positively predicted self-efficacy at Waves 2 and 3. Self-efficacy at Waves 1 and 2 negatively predicted negative coping style at Waves 2 and 3, while negative coping style at Waves 1 and 2 did not significantly predict self-efficacy at Waves 2 and 3. These results indicated the reciprocal causation of self-efficacy and coping styles. Additionally, the mediation analysis revealed that FSC at Wave 2 played a mediating role in the unidirectional association between self-efficacy at Wave 1 and negative coping style at Wave 3. CONCLUSIONS: These findings suggest that self-efficacy and coping style have mutual influences over time partly explained by university students' FSC. Consequently, the results offer potential applied value for promoting positive coping strategies among university students.

Reciprocal relations between future time perspective and academic achievement among adolescents: A four-wave longitudinal study.

INTRODUCTION: Adolescents' academic achievement is closely associated with their future time perspective. However, the reciprocal nature of this relationship remains ambiguous due to a lack of longitudinal studies. This study investigated the developmental trajectories of future time perspective and academic achievement among adolescents, as well as reciprocal relations between future time perspective and academic achievement. METHODS: Between 2017 and 2019, we collected 373 adolescents' (baseline Mage = 14.48, SD = 1.90; 49% girls) future time perspective and academic achievement four times from Henan and Hunan Province, China. Each is separated by a 6-month interval. RESULTS: Chinese adolescents' future time perspective was relatively stable. Regarding academic achievement, two distinct developmental trajectories of academic achievement were identified (i.e., high positive growth class and low negative growth class). Those who excel tended to experience an upward trajectory, while those with poorer grades continued to experience a downward trajectory. In the high positive growth class, the intercept of future time perspective was positively correlated with the rate of academic achievement growth, whereas, in the low negative growth class, it negatively predicted the rate of academic achievement decline. More importantly, reciprocal relations existed between future time perspective and academic achievement. CONCLUSIONS: Adolescents' future time perspective may serve as a protective factor for academic achievement, while high academic achievement may also benefit future time perspective. Interventions to enhance academic achievement should prioritize cultivating adolescents' future perspectives. Additionally, preventing the adverse consequences of subpar academic achievement on future time perspective is imperative.

Analysis of dissolved oxygen influencing factors and concentration prediction using input variable selection technique: A hybrid machine learning approach.

Accurate quantification of dissolved oxygen (DO) is critically important for the protection and management of aquatic ecosystems. Successful applications have utilized mechanistic and data-driven models to simulate DO content in aquatic ecosystems. However, mechanistic models present challenges due to their complex and difficult-to-solve conditions, making them less portable. Additionally, data-driven model predictions are hindered by the challenge of numerous input variables, impacting both the running speed and prediction performance of the model. To address these challenges, water quality data and meteorological data of the Tanjiang River were obtained. The maximum information coefficient (MIC) input variable selection technique was employed to identify primary environmental factors influencing DO changes. Furthermore, coupled with support vector regression (SVR), two models (SVR and MIC-SVR) were employed to estimate the DO concentration of the Tanjiang River, and the optimal model was established. The results indicated a shift in the primary pollution factor from ammonia nitrogen to total phosphorus after recent treatment in the Tanjiang River. In comparison with the SVR model, the root mean square error (RMSE) of the MIC-SVR model was reduced by 4.46%, and the Nash-efficiency coefficient (NSE) was improved by 45.85%. In addition, study of kernel function selection revealed that considering as many kernel functions as possible is necessary for improving the performance of the SVR model. Conclusively, the proposed MIC-SVR model serves as an effective tool to analyze the relationship between DO and environmental factors, identifying the primary causes of low DO, and accurately predict the DO concentration in the Tanjiang River (especially in its middle and lower reaches), thus providing a reference for governmental decision-making on water environmental protection and water resource management.

CAC: Confidence-Aware Co-Training for Weakly Supervised Crack Segmentation.

Automatic crack segmentation plays an essential role in maintaining the structural health of buildings and infrastructure. Despite the success in fully supervised crack segmentation, the costly pixel-level annotation restricts its application, leading to increased exploration in weakly supervised crack segmentation (WSCS). However, WSCS methods inevitably bring in noisy pseudo-labels, which results in large fluctuations. To address this problem, we propose a novel confidence-aware co-training (CAC) framework for WSCS. This framework aims to iteratively refine pseudo-labels, facilitating the learning of a more robust segmentation model. Specifically, a co-training mechanism is designed and constructs two collaborative networks to learn uncertain crack pixels, from easy to hard. Moreover, the dynamic division strategy is designed to divide the pseudo-labels based on the crack confidence score. Among them, the high-confidence pseudo-labels are utilized to optimize the initialization parameters for the collaborative network, while low-confidence pseudo-labels enrich the diversity of crack samples. Extensive experiments conducted on the Crack500, DeepCrack, and CFD datasets demonstrate that the proposed CAC significantly outperforms other WSCS methods.

[Study on anti-inflammatory activity of phenolic acids from Leucas ciliata].

The chemical constituents from Leucas ciliata belonging to Leucas genus in Lamiaceae were systematically explored by silica gel column chromatography, ODS column chromatography, Sephadex LH-20 gel column chromatography, and preparative high performance liquid chromatography, and seventeen phenolic acids were isolated. The chemical structures of the compounds were identified by their physicochemical properties, spectroscopic data, and literature. They were 4-hydroxyphenethyl ethyl succinate(1), 4-hydroxyphenethyl methyl succinate(2), 2-(4-hydroxyphenyl) ethyl acetate(3), p-hydroxyphenylethyl anisate(4), cassia cis-trans diphenylpropanoid(5), p-coumaric acid(6), 3,4-dihydroxybenzenepropionic acid methyl ester(7), caffeic acid(8), trans-p-hydroxyl ethyl cinnamate(9), methyl p-hydroxybenzeneacetate(10), 4-hydroxyphenethyl alcohol(11), syringic acid(12), vanillin(13), protocatechuic acid(14), salicylic acid(15), p-hydroxybenzaldehyde(16), and diorcinol(17). Among them, compound 1 was new, and compounds 2-10, 12, 14, and 16-17 were isolated from the plants belonging to Leucas genus for the first time. All compounds were obtained from L. ciliata for the first time. The anti-inflammatory activity of compounds 1-17 on NO production in lipopolysaccharide(LPS)-induced mouse leukemia cells of monocyte macrophage(RAW264. 7) cells was evaluated. The results showed that compounds 5, 7, and 9 exhibited significant anti-inflammatory activity, with IC50values of(10. 14±0. 36)-(21. 17±0. 11) µmol·L~(-1).

Future Self-Continuity Predicts Health-Promoting Behaviors of Chinese Rural College Students: Evidence from Mental Imagery Intervention.

The purpose of this research is to investigate the prediction effect of future self-continuity (FSC) on health-promoting behaviors (Health Responsibility, Physical Activity, and Nutritional Habits) and the impact of urban-rural differences in Chinese college students, further verifying the effect of mental imagery practice on enhancing FSC and promoting health-promoting behaviors among students from rural areas. Study 1 used the Future Self-Continuity Questionnaire and a sub-scale of the Health Promotion Lifestyle Profile-II to examine the relationship between FSC and health-promoting behaviors among 788 college students (430 from rural areas and others from urban areas). Study 2 was designed to examine the impact of intervention on FSC and health-promoting behaviors among Chinese rural students. The intervention activities lasting 4 wk. 162 freshmen were randomly divided into intervention or control groups to practice the mental imagery about the future self or meditation in the present once a week. FSC and health-promoting behaviors were tested for 3 times. The results demonstrated that: (1) Rural students had lower scores in FSC and health-promoting behaviors than urban students; (2) Urban-rural differences of students moderated the effect of FSC on health-promoting behaviors; (3) The mental imagery practiced increased FSC; and (4) FSC played a complete mediating role in the effect of condition (intervention or not) on health-promoting behaviors for rural college students. Overall, these findings contribute to a deeper understanding of the relationship between FSC and health-promoting behaviors, and suggest that mental imagery practice can increase Chinese rural college students' health-promoting behaviors by enhancing their FSC.

Another way to measure balanced time perspective: Development and validation of the Time Perspective Inventory.

The existing scales for measuring balanced time perspective (BTP) have limitations, such as poor-fitting structures or a complex calculation method. Based on previous studies, we conceptualize BTP as an individual's overall positive outlook on the past and future and mindfully living in the present. The present study aimed to develop the Time Perspective Inventory (TPI) for Chinese adults, determine its psychometric properties, and examine a simple calculation method for generating a score to represent BTP. In study 1, a 7-factor structure of TPI - Past Positive, Past Negative, Mindful Present, Present Hedonistic, Present Excessively Task-oriented, Future Positive, and Future Negative - was established through exploratory (sample 1, N = 529) and confirmatory (sample 2, N = 577) factor analyses. Findings supported the internal consistency, test-retest reliability, and criterion-related validity of the TPI. We proposed using the score difference between positive time perspectives and negative time perspectives to calculate the BTP. Findings showed that the correlations between BTP and subjective well-being indicators and anxiety were higher than among individual dimensions of TPI. Study 2 (sample 3, N = 713) compared the effects of the TPI and the Chinese version of the Zimbardo Time Perspective Inventory (ZTPI-C) on well-being indicators and anxiety. Results indicated that the variance of life satisfaction, positive affect, negative affect, and anxiety explained by BTP measured with TPI was higher than deviation from BTP (DBTP) measured with ZTPI-C. Together, the TPI yields reliable and valid BTP scores among Chinese adults.

Four new diterpenoids from the aerial parts of Leucas zeylanica (L.) R. Br.

Four new undescribed halimane- and labdane-type diterpenoids, named zeylleucapenoids E-H (1-4), along with four known analogues (5-8), were isolated from the aerial parts of Leucas zeylanica (L.) R. Br. Their structures were determined by comprehensive spectroscopic analysis and computational calculations. Compounds 1 and 2 are the highly modified halimane diterpenoids featuring a 6/6/6-fused tricyclic system with an unusual six-membered 6,11-ether ring. Compound 8 exhibits nontoxic effects for zebrafish embryo, while it displays efficient reduction against NO production in a dose-dependent manner and strongly suppresses the secretion of LPS-induced TNF-α and IL-6 cytokines in RAW264.7 macrophages. In addition, marked reductions of iNOS and COX-2 expression were observed. Molecular docking analysis indicated that 8 has high affinities with the target amino acid residues on protein-binding sites, which may be a possible mechanism contributing to the anti-inflammatory potential of this molecule.

Dynamical evolution of CO2 and H2O on garnet electrolyte elucidated by ambient pressure X-ray spectroscopies.

Garnet-type Li6.5La3Zr1.5Ta0.5O12 (LLZO) is considered a promising solid electrolyte, but the surface degradation in air hinders its application for all-solid-state battery. Recent studies have mainly focused on the final products of the LLZO surface reactions due to lacking of powerful in situ characterization methods. Here, we use ambient pressure X-ray spectroscopies to in situ investigate the dynamical evolution of LLZO surface in different gas environments. The newly developed ambient pressure mapping of resonant Auger spectroscopy clearly distinguishes the lithium containing species, including LiOH, Li2O, Li2CO3 and lattice oxygen. The reaction of CO2 with LLZO to form Li2CO3 is found to be a thermodynamically favored self-limiting reaction. On the contrary, the reaction of H2O with LLZO lags behind that of CO2, but intensifies at high pressure. More interestingly, the results provide direct spectroscopic evidence for the existence of Li+/H+ exchange and reveal the importance of the initial layer formed on clean electrolyte surface in determining their air stability. This work demonstrates that the newly developed in situ technologies pave a new way to investigate the oxygen evolution and surface degradation mechanism in energy materials.

Stepped-Tube Backside Cavity Piezoelectric Ultrasound Transducer Based on Sc0.2AI0.8N Thin Films.

This paper presents a novel piezoelectric micromachined ultrasonic transducer (PMUT) with theoretical simulation, fabrication, and testing. Conventional methods using a PCB or an external horn to adjust the PMUT acoustic field angle are limited by the need for transducer size. To address this limitation, the stepped-tube (expanded tube) backside cavity PMUT has been proposed. The stepped-tube PMUT and the tube PMUT devices have the same membrane structure, and the acoustic impedance matching of the PMUT is optimized by modifying the boundary conditions of the back cavity structure. The acoustic comparison experiments show that the average output sound pressure of the stepped-tube backside cavity PMUT has increased by 17%, the half-power-beam-width (θ-3db) has been reduced from 55° to 30° with a reduction of 45%, and the side lobe level signal is reduced from 147 mV to 66 mV. In addition, this work is fabricated on an eight-inch wafer. The process is compatible with standard complementary metal oxide semiconductor (CMOS), conditions are stable, and the cost is controllable, plus it facilitates the batch process. These conclusions suggest that the stepped-tube backside cavity PMUT will bring new, effective, and reliable solutions to ranging applications.