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In this work, AlN whisker-reinforced (Zr, Hf)O 2 coating was prepared on SiC coated carbon/carbon composites by sol-gel and plasma spraying methods. Its cyclic ablation resistance was evaluated using an oxyacetylene torch with a heat flux of 2.38 MW/m2. After ablation, the coating showed apparently decreased crack sizes and quantity as compared with the one without AlN whisker addition, pointing out its better crack tolerance. Moreover, the coating had a thinner oxidized region based on the linear ablation rate (−0.042 µm/s), greatly lower than that of pure oxide coating (−0.922 µm/s). After detailed observation and characterization, probable protection mechanism was proposed. [ABSTRACT FROM AUTHOR]

There is an urgent need for the thermal protection of carbon/carbon composites to increase their service span in aerospace field. As members of ultra-high temperature ceramics, HfC and ZrC are thought to be alternative materials, but their poor oxidation behavior and fracture toughness at temperature over 2000 ℃ prevent them from taking full advantages. Herein, we synthesized nanosized Hf 6 Ta 2 O 17 powders and introduced them into HfC ceramic to tackle the above problems. Plasma-sprayed HfC coatings with Hf 6 Ta 2 O 17 varied from 0 to 15 mol.% (0, 1.25, 2.5, 5, 15) were exposed to an oxyacetylene torch with a heat flux of 2.38 MW/m2. The one with 2.5 mol.% Hf 6 Ta 2 O 17 showed the best ablation resistance. Smaller doping was unable to effectively hinder oxygen diffusion given the inadequate compactness of the formed scale, conversely substantial humps and ruptures formed on the samples with higher amounts, acting as straightforward paths for oxygen. • Nanosized Hf 6 Ta 2 O 17 powders were synthesized using sol-gel method. • HfC coatings with various Hf 6 Ta 2 O 17 amounts were fabricated on carbon/carbon composites by plasma spraying. • The sample containing 2.5 mol.% Hf 6 Ta 2 O 17 was supposed as the one with the best ablation resistance. • The ablation mechanisms of the samples were proposed based on the microstructure changes. [ABSTRACT FROM AUTHOR]

Purpose: This study assessed the effects of character strengths-based invention (CSI) vs group counseling (GC) on mental health outcomes (ie, post-traumatic growth, well-being, and depression) among university students in Guangdong Province, China. Materials and Methods: We conducted a randomized non-inferiority trial among 124 undergraduates at a medical university during the COVID-19 pandemic. We randomly allocated students to receive either CSI (n=62) or GC (n=62). A qualified psychologist delivered both activities on campus during two consecutive weekends with a total of 7.5 hours and also gave assignments to students during weekdays. We measured the outcomes at pre-intervention, post-intervention, and 1-month follow-up. We then analyzed data using descriptive statistics and a general linear mixed model. Results: CSI and GC groups had similar baseline characteristics. Both CSI and GC experienced an increase in post-traumatic growth and well-being. The mean±SD scores for post-traumatic growth were significantly higher in CSI compared to GC groups (87.70± 14.22 vs 78.15± 20.72, respectively), whereas well-being scores were similar between CSI and GC (82.58± 16.57 vs 83.68± 15.59, respectively). Neither CSI nor GC experienced a reduction in depression scores. Conclusion: CSI had non-inferior effects compared to GC with regards to improvement of post-traumatic growth and well-being during the COVID-19 pandemic. However, caveats regarding lack of blinding of investigator and limited generalizability should be considered in the interpretation of the study findings. [ABSTRACT FROM AUTHOR]

Based on the investigation of ablation behavior and thermal stress of the monolayered ZrC-SiC coatings with different SiC amounts, an alternate coating consisting of 4 sublayers with 10 and 70 vol.% SiC was prepared on SiC-coated carbon/carbon (C/C) composites through plasma spraying technique. Ablation tests were carried out under oxyacetylene torch with a heat flux of 2.38 MW/m2. The alternate coating could offer 90 s ablation shield for C/C composites, providing superior ablation properties than all monolayered coatings. The improved ablation resistance is mostly induced by the fact that the outmost scale with abundant ZrO 2 particles was able to better endure the mechanical denudation from the torch. Moreover, due to the indirect contact with torch, the innermost sublayers were placed into relatively mild environment, thereby most of Si-based oxides could be retained and further hinder oxygen transport inward during ablation. [ABSTRACT FROM AUTHOR]

In this work, ZrO 2 with different ZrB 2 contents (0, 15, 30,40 wt%) composite powders were synthesized by sol-gel, then they were sprayed on carbon/carbon composites using plasma spraying to construct a three-dimensional (3D) thermal conduction network within the formed coating. Oxyacetylene ablation tests were carried out under 4.2 MW/m2 to investigate the effect of the 3D thermal conduction network on the ablation resistance of coated samples. The encapsulation structure formed during sol-gel process benefits to slowing the oxidation rate of ZrB 2 and the content of ZrB 2 is critical for establishing a stable 3D thermal conduction network within the coating. • ZrO 2 -encapsulated ZrB 2 powders were fabricated and sprayed on the surface of C/C composites. • The 3D thermal conduction network was constructed in the formed coating. • The ablation resistance of coated samples was evaluated under a heat flux of 4.2 MW/m2. • The coating with 3D thermal conduction network sustained a milder environment and exhibited better ablation resistance. [ABSTRACT FROM AUTHOR]

Background: Despite widespread application of the Symptom Check-List-90-R (SCL-90-R) for Chinese undergraduate students, there are no appropriate norms for them. The aim of this study is to provide norms for the Chinese version of the tool for undergraduate students using a large and representative sample.Methods: Four thousand eight hundred sixty students completed the scale of SCL-90. The mean scores obtained in the present study were compared with mean scores from previous normative samples.Results: The mean scores for nine subscales of the SCL-90-R ranged from (1.36 ± 0.46) ~ (1.77 ± 0.63) and the mean (standard deviation) Global Severity Index (GSI) was 1.50 (0.49). Relative to previous normative studies, the findings suggested that Chinese undergraduate students' self-reported mental health symptoms decreased in interpersonal sensitivity, depression, hostility, and paranoid ideation subscales.Conclusion: It is necessary to revise the norms of the Chinese version of the SCL-90-R for undergraduate students. [ABSTRACT FROM AUTHOR]

Background: Despite the widespread application of the Chinese version of Symptom Check List 90 (SCL-90) amongst undergraduate students, researchers have not thoroughly evaluated its psychometric features with representative samples of Chinese undergraduate students. Aim: To evaluate its psychometric properties based on a large, representative sample of Chinese undergraduate students. Methods: A total of 4456 Chinese undergraduate students (age range = 17-25 years) completed the SCL-90. Correlation analysis, confirmatory factor analysis and structural equation modeling were used to evaluate its reliability and validity. Results: The evidence for item-total correlations, internal consistency reliability, intraclass correlation coefficients and composite reliability, and the hypothesized factor structure was satisfactory. The evidence for convergent validity was acceptable; however, the evidence for discriminant validity was not satisfactory. Conclusion: Based on a large, representative sample of Chinese undergraduate students, the Chinese version of the SCL-90 revealed both strengths and limitations, suggesting the need for further research. [ABSTRACT FROM AUTHOR]

Objective: We compare the reliability and validity of the Short Form 36 (version 1, SF-36) and the Short Form 12 (version 1, SF-12) in adolescence, the period of life when a child develops into an adult, i.e., the period from puberty to maturity terminating legally at the age of majority (10-19 years), thus supplying evidence for the selection of instruments measuring the quality of life (QOL) and decision-making processes of adolescents in China.Methods: Stratified cluster random sampling was adopted according to geographical location, and the SF-36 was administered to assess QOL. The Pearson correlation coefficient was used to show correlation. Cronbach's alpha and construct reliability (CR) were used to evaluate the reliability of SF-36 and SF-12, while criterion validity and average variance extracted (AVE, convergence validity) were used to evaluate validity. Confirmatory factor analysis was used to calculate the load factors for the items of the SF-36 and SF-12, then to obtain the CR and AVE. The Semejima grade response model (logistic two-parameter module) in item response theory was used to estimate item discrimination, item difficulty, and item average information for the items of the SF-36 and SF-12.Results: 19,428 samples were included in the study. The mean age of respondents was 14.78 years (SD = 1.77). Reliability of each domain of the SF-36 was better than for the corresponding domain of the SF-12. The domains of PF, RP, BP, and GH in SF-36 had good construct reliability (CR > 0.6). The criterion validities of some domains of the SF-36 were a little higher in some corresponding dimensions of the SF-12, except for PCS. The convergence validities of the SF-12 were higher than the SF-36 in PF, RP, BP, and PCS. The items of BP, SF, RP, and VT in the SF-12 had acceptable discrimination of items that were higher than in the SF-36. The items' average amounts of information on BP, VT, SF, RE, and MH in the SF-36 and SF-12 were poor.Conclusion: Two component (PCS and MCS) measurements of the SF-12 appeared to perform at least as well as the SF-36 in cross-sectional settings in adolescence, but the reliability and validity of the 8 domains of the SF-36 were better than those of the SF-12. Some domains, for instance SF and BP, were not suitable for adolescents or need to be studied further. [ABSTRACT FROM AUTHOR]

In this work, ZrC and ZrO 2 coatings were prepared on SiC-coated carbon/carbon (C/C) composites by supersonic atmospheric plasma spraying. Their ablation behavior was investigated and compared under different heat fluxes to design multilayer anti-ablation structural coating. Results shown that ZrO 2 coating exhibited denser oxide layer and lower mass consumption after ablation. According to their microstructure and thermal analysis, possible reasons can be ascribed to higher surface temperature and lower melting point of ZrO 2 coating, which made the scale easier to be sintered during ablation. Moreover, the ablated ZrC coating presented particle accumulation structure at the initial ablation stage, hence causing the consumption from mechanical denudation to occur in these particles preferentially rather than sintering. [ABSTRACT FROM AUTHOR]

HfC-TaC/HfC-SiC alternate coatings with different sublayer thicknesses were fabricated on SiC-coated carbon/carbon composites by supersonic atmosphere plasma spraying. Their ablation resistance was studied under oxyacetylene torch and compared with monolayered HfC-TaC coating. The alternate coating with 6 spray cycles of HfC-TaC and 3 spray cycles of HfC-SiC sublayers exhibited the best ablation performance as confirmed by the integral coating morphology and the lowest ablation rates. A dense oxide layer acting as an oxygen insulator and the release of thermal stress induced by the formation of dendritic cracks are thought to be responsible for its great ablation resistance. For the alternate coating with 4 spray cycles of HfC-TaC and 2 spray cycles of HfC-SiC sublayers, exfoliation occurred at the interface of two adjacent sublayers, leading to violent evaporation of exposed HfC-SiC sublayer. [ABSTRACT FROM AUTHOR]

Several multilayer architectures, based on ZrC-SiC system, were fabricated on SiC-coated carbon/carbon composites by plasma spraying and tested using an oxyacetylene torch. A remarkable variance in scale evolution was found in these multilayer coatings, referring to close correlation between multilayer architecture and ablation behavior. The multilayer coating made of consecutive sublayers of ZrC-10, 30, 10 and 70 vol% SiC survived three repeated ablation cycles with mass ablation rate of −0.467 mg/s and linear ablation rate of − 0.411 µm/s. Detailed phase analysis and morphology investigation attributed its preferable ablation performance to the formation of multifunctional scale and modest thermal stress. • Various ZrC-SiC multilayer coatings were prepared on SiC-coated C/C composites by plasma spraying. • The relationship between coating architecture and ablation behavior was studied using oxyacetylene torch. • Ablation mechanism was analyzed systematically as well as the roles of different sublayers. • Theoretical analysis was adopted to compare the stress level within these multilayer coatings. [ABSTRACT FROM AUTHOR]

Aiming to ameliorate the rapid oxidization and deterioration of carbon/carbon (C/C) composites in extreme environments, a novel multilayer coating containing ZrO 2 -Y 2 O 3 , ZrC-ZrO 2 and ZrC-SiC layers from surface to inside was prepared on SiC-coated C/C composites via plasma spraying. Its scale evolution was studied under exposure to an oxyacetylene torch above 2000 ℃. Only the multilayer coating survived after ablation for 90 s × 2 and maintained an integrated appearance, whereas the other monolayered coatings were failure prematurely. The monotonically decreased thermal expansion and multiple roles gathering thermal shield, crack termination and oxidation retardation accounted for its preferable ablation resistance. • A novel zirconium-based multilayer coating was fabricated on SiC-coated C/C composites by plasma spraying. • It owned preferable ablation property than monolayered coatings under exposure to oxyacetylene torch. • Monotonically reduced thermal expansion lessened the detrimental effect of cracks. • The scale with multiple characters including thermal shield, gradient and oxidation retardation accounted for its high protection. [ABSTRACT FROM AUTHOR]

Efficient removal of antibiotics from aqueous solution is of fundamental importance due to the increasingly severe antibiotic-related pollution. Herein, a high-performance Fe-ZIF-8-500 adsorbent was synthesized by Fe-doping strategy and subsequent activation with high-temperature. In order to evaluate the feasibility of Fe-ZIF-8-500 as an adsorbent for tetracycline (TC) removal, the adsorption properties of Fe-ZIF-8-500 were systematically explored. The results showed that the Fe-ZIF-8-500 exhibited ultrahigh adsorption capacity for TC with a record-high value of 867 mg g-1. Additionally, the adsorption kinetics and isotherms for TC onto the Fe-ZIF-8-500 can be well-fitted by the pseudo-second-order kinetics model and the Freundlich model, respectively. The ultrahigh adsorption capacity of Fe-ZIF-8-500 can be explained by the synergistic effect of multi-affinities, i.e., surface complexation, electrostatic attraction, π-π interaction and hydrogen bonding. After being used for four cycles the adsorption capacity of Fe-ZIF-8-500 remains a high level, demonstrating its outstanding reusability. The ultrahigh adsorption capacity, excellent reusability, satisfactory water stability and easy-preparation nature of Fe-ZIF-8-500 highlight its bright prospect for removing tetracycline pollutant from wastewater. [Display omitted] • Fe-ZIF-8 is prepared by doping Fe in the synthesis of the ZIF-8. • The heat treatment provides an efficient tool for improving the TC adsorption performance of the Fe-ZIF-8. • The Fe-ZIF-500 demonstrated satisfactory reusability and regenerability. • The Fe-ZIF-500 exhibited an ultrahigh adsorption capacity which is remarkably higher than the pristine ZIF-8. [ABSTRACT FROM AUTHOR]