This study aims to examine the mediating role of self-efficacy (SE) and self-control (SC) in the relationship between physical activity (PA) and aggressive behaviors (AB) among college students. It ...provides a basis for the prevention and control of AB among college students. This study employed a survey research methodology, including the PA Level Scale, the General Self-efficacy Scale, the Self-control Scale, and the Chinese Aggressive Behaviors Scale on 950 college students. The chain mediating effect test and Bootstrap analysis were applied. The results were as follows: (1) There was a main effect of PA on SE, SC, and AB as well as all sub-indicators (physical aggression, verbal aggression, anger, hostility, self-directed aggression), i.e., PA had a direct effect on the control of all three; (2) PA level was significantly negatively correlated with AB and significantly positively correlated with SE and SC. That is, the higher the level of PA, the better the SE and SC, and the lower the probability of AB; (3) The three pathways had mediating effects: PA → SE → AB, PA → SC → AB, PA → SE → SC → AB, with effect sizes of 8.78%, 28.63%, and 19.08%, respectively. It is concluded that regular PA is a potent method for decreasing aggressive behavior and psychological issues in university students while additionally promoting self-efficacy and self-control. Increasing the intensity of PA may enhance the effectiveness of these chain benefits.
Two Fe-based electrocatalysts with different ORR selectivity were synthesized from MIL-101, which show promising prospect in Zn-air and H2O2 production.
Display omitted
•Two ORR electrocatalysts with ...different selectivity was obtained from MIL-101.•Fe3O4@NCNTs shows 4e-ORR activity in both alkaline and neutral electrolyte.•Fe2O3 exhibits typical 2e-ORR character with high H2O2 production rate.•The connection between structure and ORR selectivity is clarified.
Fe-based materials are famous electrocatalysts in oxygen reduction reaction (ORR), but their selectivity towards four- or two-electron ORR still requires further research in detail. Herein, two Fe-based ORR electrocatalysts are synthesized from MIL-101, a metal–organic framework (MOF). After calcined with dicyandiamide (DCDA) under N2 protection, Fe3O4@NCNTs (NCNTs = N-doped carbon nanotubes) is synthesized, in which small Fe3O4 particles reside in NCNTs homogeneously. It is a typical four-electron electrocatalyst in both alkaline and neutral electrolyte. Without DCDA, Fe2O3 forms and it acts as two-electron electrocatalyst in ORR. Theoretical calculation suggests the discrepancy in ORR selectivity between Fe3O4@NCNTs and Fe2O3 roots from their different interactions with OOH*. If Fe3O4@NCNTs serves as cathode material, peak power density of Zn-air battery reaches 125.1 mW·cm−2 in alkaline electrolyte. When discharge at 10 mA·cm−2, the specific capacitance and energy density reach 799.7 mAh·g−1 and 839.7 Wh·kg−1. The performance of Fe3O4@NCNTs is also well kept in neutral Zn-air battery. We expect this work elucidates the effect of structure on ORR selectivity for Fe-based electrocatalysts.
All-inorganic CsPbBr3 nanocrystal (NC) has been extensively studied because of its excellent optical properties. However, its poor stability restricts further practical applications. Glass as a ...carrier can solve this problem well while still maintaining excellent luminescent properties. The traditional CsPbBr3 NC glass is obtained by melt-quenching and heat treatment. In this paper, we first propose LiBr-induced the self-crystallization of CsPbBr3 NC in borosilicate glass without heat treatment. We demonstrated that the lithium changes the glass network structure, resulting in a higher aggregation state in the glass. At the same time, the lithium doping increases the degree of phase separation of the glass. Both of these two factors benefit the formation of the CsPbBr3 NC. The self-crystallized CsPBbr3 NC glass has better luminescent properties than NC glass obtained by heat treatment. What is more, the self-crystallized CsPbBr3 NC glass shows good environmental and water stability, especially thermal stability. We combined blue and red phosphors to construct a white light-emitting diode (WLED), which has excellent application prospects. Our work paves a new path for the research of perovskite nanocrystals, and provides promising development for future optoelectronic applications.
•A series of self-crystallized CsPbBr3 NC glasses were prepared.•The mechanism of self-crystallized CsPbBr3 NC glass was well studied.•The self-crystallized CsPbBr3 NC glass has improved luminescent properties and stability.•High-performance WLED was assembled successfully by self-crystallized CsPbBr3 NC glass.
Making illumination light sources become comfortable to the human eye is a long‐term effort, which justifies the current research on warm white‐light‐emitting diodes (w‐LEDs). In this work, a novel ...phosphor for w‐LEDs, namely SrGa12O19: Dy3+(SGO: Dy3+), with a low‐color temperature (CT) was designed and synthesized. The crystal structure, the luminescence properties, the thermoluminescence properties and the stability of SGO: Dy3+ were investigated. We demonstrate outstanding luminescent characteristics and excellent stabilities. The intensity of emission light keep remained when excited by a flickering light source with a chopping speed or off‐time of a few seconds, which indicates that the SGO: Dy3+ phosphor has anti‐flicker properties that will be useful for potential applications, as LEDs driven by alternating current (AC‐LED). The chromaticity coordinates and the correlated color temperature (CCT) of SGO: Dy3+ phosphors with different Dy3+ concentrations are close with an optimal doping at 4.00 mol% Dy3+ for chromaticity coordinate (0.4269, 0.4348) and a lowest CCT of 3361 K. The perfect weatherability of this phosphor was also confirmed since the phosphorescence intensity and the color were stable at high temperature and in a high humidity environment. The performance obtained shows that SGO: Dy3+ is a suitable candidate for illumination sources that are beneficial to human health.
It has been an urgent need for developing a new bright long‐wave emitting phosphor to improve the color rendering index (CRI) of white light‐emitting diodes (WLEDs). Here, based on the concept of ...oxygen vacancy‐induced long‐wave emission by Bi3+ doping, we selected BaSrGa4O8 as the matrix, which has a low‐dimensional chain structure that can produce enough oxygen vacancies. After the introduction of Bi3+, orange emission was successfully achieved. To further improve the luminescence efficiency, the system of BaSrGa4O8:Bi3+,K+ was designed. Interestingly, although significant emission enhancement was obtained, the material showed reduced absorption with increased oxygen vacancies. More detailed experimental evidences confirm that oxygen vacancies can activate Bi3+ to achieve long‐wave emission. Our results provide a new way to design Bi3+‐based long‐wave emitting phosphors with low‐dimensional crystal structure. Finally, a WLED device containing BaSrGa4O8:Bi3+,K+ was fabricated and exhibited an enhanced CRI, which shows a promising application in WLEDs.
After potassium ions got into the lattice, more oxygen vacancies can be produced, leading to the enhanced Bi3+ splitting. This behaviour increased the intensity of photoluminescence for a significant enhancement of orange‐red light emission.
The emerging challenges of the big data era, both in storage density and security, require the development of the next-generation optical data storage materials. Here, we report for the first time a ...photo-stimulated luminescence (PSL) material, Ba3Ga2O6: Pr3+, for rewritable optical storage and write-once-read-many data preservation. Ba3Ga2O6: Pr3+, with an isolated deep trap depth in the range 1.26–1.53eV, has been used for data encoding/decoding under the excitation of 254 nm UV light and by the simulation of an 808 nm NIR laser. Meanwhile, the phosphor allows for high-security write-once-read-many optical memory by taking advantage of the irreversible change of the photoluminescence (PL) color from blue to green (a binary blue ‘0’ and green ‘1’ code) irradiated by 365 nm UV light. The comprehensive investigations indicate that the irreversible PL switching is as a result of the order-disorder structural transition by thermal treatment. The new persistent luminescence material not only exhibits promising applications in sustainable rewritable data storage, but also paves the way for write-once-read-many optical information storage with a high level of security.
Near infrared to near infrared (NIR–NIR) photo-stimulated persistent luminescence (PSPL) has shown excellent potential in high-resolution bioimaging for deep tissues. However, the PSPL in NIR-Ⅱ ...region (900–1700 nm) is still lacking. In this work, Ca2Ga2GeO7:Yb3+,Tb3+ (CGGYT) phosphor with unique low-dimensional crystal structure was synthesized by high-temperature solid–state reaction. Thanks to the carriers transferring from deep traps to shallow ones induced by low energy light, the 978 nm PSPL originating from 2F5/2 to 2F7/2 transition of Yb3+ induced by multimode stimulating (980 nm or WLED) is successfully realized after pre-excited by UV lamp. The NIR PSPL of the specimen can be repeatedly stimulated after placed in dark for 12 h. Moreover, the results indicate that codoping with Tb3+ can significantly enhance the NIR-II PSPL owing to the quantum cutting persistent energy transfer (QC PET) from Tb3+ to Yb3+. Our study points to a new direction for the future development of multimode PSPL materials for bioimaging or multimode optical storage applications.
The NIR LPL and NIR–NIR PSPL in the 978 nm of Yb3+ are obtained in CGG host. And these emissions can be significantly enhanced by continuous energy transfer from Tb3+ to Yb3+. Therefore, CGG:Yb3+,Tb3+ phosphor enriches the biological luminescence probes of the second biological window. Display omitted
Abstract
It has been an urgent need for developing a new bright long‐wave emitting phosphor to improve the color rendering index (CRI) of white light‐emitting diodes (WLEDs). Here, based on the ...concept of oxygen vacancy‐induced long‐wave emission by Bi
3+
doping, we selected BaSrGa
4
O
8
as the matrix, which has a low‐dimensional chain structure that can produce enough oxygen vacancies. After the introduction of Bi
3+
, orange emission was successfully achieved. To further improve the luminescence efficiency, the system of BaSrGa
4
O
8
:Bi
3+
,K
+
was designed. Interestingly, although significant emission enhancement was obtained, the material showed reduced absorption with increased oxygen vacancies. More detailed experimental evidences confirm that oxygen vacancies can activate Bi
3+
to achieve long‐wave emission. Our results provide a new way to design Bi
3+
‐based long‐wave emitting phosphors with low‐dimensional crystal structure. Finally, a WLED device containing BaSrGa
4
O
8
:Bi
3+
,K
+
was fabricated and exhibited an enhanced CRI, which shows a promising application in WLEDs.
Ferrite nanoparticles are widely used in magnetic resonance imaging as T2 contrast agent particles. In this study, we propose to utilize Mn and Zn doping into ferrite to prepare Mn-Zn doped ferrite ...and use it as T2 contrast agent core particles. Also, we aim to clarify the relationship between the Mn-Zn doped ferrite nanoparticles orientation and ratio of surfactant oleic acid to oleylamine as well as different solvents. The results show that high temperature thermal decomposition method can successfully prepare uniformly doped Mn-Zn ferrite nanoparticles (Mn0.6Zn0.4Fe2O4). And the ratio of surfactant oleic acid to oleylamine has a significant impact on the orientation of Mn0.6Zn0.4Fe2O4 nanoparticles growth. As the ratio of oleic acid increases, the Mn0.6Zn0.4Fe2O4 nanoparticles gradually change from growing along the 110 crystal direction to growing randomly with irregular orientation, the nanoparticles morphology and size tend from rhombohedral (37 nm) to spherical (9.84 nm). In terms of solvent, benzyl ether, 1-octadecene and hexadecylamine have no influence on the action of surfactants. The Mn0.6Zn0.4Fe2O4 nanoparticles in the three solvents are grown randomly without any obvious orientation changes. All nanoparticles are spherical nanoparticles, indicating that the choice of the three solvents has little effect on the orientation of the nanoparticles. However, the three different solvents affect the crystallinity of Mn0.6Zn0.4Fe2O4 nanoparticles. Nanoparticles prepared with diphenyl ether as solvent show a higher crystallinity compared to those synthesized with 1-octadecene and hexadecylamine as solvents. In contrast performance, under the optimal surfactant ratio (11:1) and solvent selection (dibenzyl ether), the transverse relaxation rate r2 value of Mn-Zn ferrite nanoparticles reach 266.24 mM−1s−1, while the longitudinal relaxation rate r1 value is 10.45 mM−1s−1. The r2/r1 ratio is significantly larger than 10, indicating that the nanoparticles with random growth orientation serve as excellent T2 weighted contrast agents.
Display omitted
