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Developing metal–organic frameworks (MOFs) with moisture-resistant feature or moisture-enhanced adsorption is challenging for the practical CO2 capture under humid conditions. In this work, under humid conditions, the CO2 adsorption behaviors of two iron-based MOF materials, PCN-250­(Fe3) and PCN-250­(Fe2Co), were investigated. An interesting phenomenon is observed that the two materials demonstrate an unusual moisture-enhanced adsorption of CO2. For PCN-250 frameworks, H2O molecule induces a remarkable increase in the CO2 uptake for the dynamic CO2 capture from CO2/N2 (15:85) mixture. For PCN-250­(Fe3), its CO2 adsorption capacity increases by 54.2% under the 50% RH humid condition, compared with that under dry conditions (from 1.18 to 1.82 mmol/g). Similarly, the CO2 adsorption uptake of PCN-250­(Fe2Co) increases from 1.32 to 2.23 mmol/g, exhibiting a 68.9% increase. Even up to 90% RH, for PCN-250­(Fe3) and PCN-250­(Fe2Co), obvious increases of 43.7 and 70.2% in the CO2 adsorption capacities are observed in comparison with those under dry conditions, respectively. Molecular simulations indicate that the hydroxo functional groups (μ3-O) within the framework play a crucial role in improving CO2 uptake in the presence of water vapor. Besides, partial substitution of Fe3+ by Co2+ ions in the PCN-250 framework gives rise to a great improvement in CO2 adsorption capacity and selectivity. The excellent moisture stability (stable even after exposure to 90% RH humid air for 30 days), superior recyclability, as well as moisture-enhanced feature make PCN-250 as an excellent MOF adsorbent for CO2 capture under humid conditions. This study provides a new paradigm that PCN-250 frameworks can not only be moisture resistant but can also subtly convert the common negative effect of moisture to a positive impact on improving CO2 capture performance.

The quantification of growth and development is an important issue in economics, because these phenomena are closely related to sustainability. We address growth and development from a network perspective in which economic systems are represented as flow networks and analyzed using ecological network analysis (ENA). The Beijing economic system is used as a case study and 11 input–output (I-O) tables for 1985–2010 are converted into currency networks. ENA is used to calculate system-level indices to quantify the growth and development of Beijing. The contributions of each direct flow toward growth and development in 2010 are calculated and their implications for sustainable development are discussed. The results show that during 1985–2010, growth was the main attribute of the Beijing economic system. Although the system grew exponentially, its development fluctuated within only a small range. The results suggest that system ascendency should be increased in order to favor more sustainable development. Ascendency can be augmented in two ways: (1) strengthen those pathways with positive contributions to increasing ascendency and (2) weaken those with negative effects.

Using ambulatory assessment, the current study investigated the dynamic impact of stress on negative emotions in daily life and explored the mediating role of rumination in this relationship. A total of 100 college students were recruited and reported their perceived stress, current ruminative thinking and negative emotions (including anxiety, depression, and anger) 5 times a day for 7 consecutive days. Mixed model analyses indicated that the higher level of stress at the current time predicted increased negative emotions at the next time including depression, anger and anxiety. At within-person level, rumination significantly mediated the relationship of stress to depression, anger, and anxiety. At between-person level, overall rumination significantly mediated the relationship between stress and angry. Findings suggested that people who perceived higher level stress may report more rumination, which in turn may lead to increases in negative emotions.

Objective: The aim of this study was to examine the comorbidity and longitudinal cross-lagged relationships between posttraumatic stress disorder (PTSD) and depression among Chinese adolescents after their experience of the Yancheng tornado. Method: A total of 154 adolescents from 2 local middle schools in Yancheng city participated in this longitudinal study. Participants completed the Child PTSD Symptom Scale and the Center Epidemiological Studies of Depression at 6 months (T1), 9 months (T2), and 12 months (T3) after the tornado, respectively. Results: Results include the following: (a) the prevalence of PTSD was 55.84% at T1, 50.00% at T2, and 47.40% at T3; the prevalence of depression was 56.49% at T1, 65.58% at T2, and 66.01% at T3; (b) the comorbidity between PTSD and depression was high, 46.75% at T1, 42.86% at T2, 43.51% at T3; (c) PTSD at T1 significantly predicted depression at T2 (β = 0.42, p < .001), and PTSD at T2 significantly predicted depression at T3 (β = 0.64, p < .001); however, depression cannot significantly predict PTSD at different cross-time points. Conclusions: The results suggest that there is comorbidity between PTSD and depression and that PTSD positively influence the development of depression in adolescents during the early period of the tornado, whereas depression did not predict PTSD. The implications of the results for the psychological services provided to children and youth are discussed.

We develop a thermal-elastic stress model using the finite element method to predict three-dimensional anisotropic stress in AlN single crystals homoepitaxially grown by the physical vapor transport process; we also perform numerical experiments for a 1-in. AlN crystal surrounded by different cone-tube designs and grown along various orientations. The influences of the cone-tube shape and the growth orientation on the stresses inside the AlN crystal are investigated in detail. The simulation results show that the von Mises stress exceeds 1.11 GPa under all specified growth conditions, while the anisotropy is negligible. The resolved shear stresses are strongly dependent on the thermal gradient inside the growing crystal and the growth orientation. Strong anisotropy of the resolved shear stress is observed upon tilting of the growth orientation. The resolved shear stress along {0001}⟨112̅0⟩ primary slip system reveals that the c-axis growing crystal is under tensile stress along all three primary slip directions. Nevertheless, an inversion of the resolved shear stress from tensile to compressive along the −a 3 slip direction is observed when changing the growth orientation. The total resolved shear stress shows 6-fold symmetry, reflection symmetry and 2-fold symmetry along [001], [10√3], and [100] growth orientations, respectively.

Crack-free bulk AlN single crystals up to 60 mm in diameter are successfully grown for the first time using a series of proprietary techniques by the physical vapor transport method. The single crystals are sliced into on-axis (AE0.2 ) wafers and then lapped/polished following common wafering standards. The obtained wafers are characterized by Raman spectroscopy and high-resolution X-ray diffraction (HRXRD). The Raman spectra show an E 2 (high) full width at half maximum (FWHM) of 2.85-2.87 cm À1 . The symmetric and asymmetric HRXRD rocking curves show FWHMs of 172-288 and 103-242 arcsec, respectively. The optical transmission spectra reveal that the entire wafers exhibit excellent ultraviolet (UV) transparency with absorption coefficients of 14-21 cm À1 in the UV range 4. 43-4.77 eV (260-280 nm). The average etch pit density (EPD) determined by preferential chemical etching is about 2.3 Â 10 5 cm À2 . The major impurities determined by evolved gas analysis and glow discharge mass spectrometry are carbon at 7.4 Â 10 18 cm À3 (45 ppmw), oxygen at 1.2 Â 10 19 cm À3 (100 ppmw), and silicon at 6.8 Â 10 17 cm À3 (9.7 ppmw). The usable area of the 60 mm wafers exceeds 98%.

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