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1.
ACS Appl Mater Interfaces ; 16(13): 16253-16260, 2024 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-38514257

RESUMEN

The CuGaTe2 thermoelectric material has garnered widespread attention as an inexpensive and nontoxic material for mid-temperature thermoelectric applications. However, its development has been hindered by its low intrinsic carrier concentration and high thermal conductivity. This study investigates the band structure and thermoelectric properties of (CuGaTe2)1-x (ZnSe)x (x = 0, 0.25%, 0.5%, 1%, 1.5%, and 2%). The research revealed that the incorporation of Zn and Se atoms enhanced the level of band degeneracy and electron density of states near Fermi level, significantly raising carrier concentration through the formation of ZnGa- point defects. Simultaneously, when the doping content reached 1.5%, the ZnTe second phase emerged, collaborating with point defects and high-density dislocations, effectively scattering phonons and substantially reducing lattice thermal conductivity. Therefore, introducing ZnSe can simultaneously optimize the material's electrical and thermal transport properties. The (CuGaTe2)0.985(ZnSe)0.015 sample reaches peak ZT of 1.32 at 823 K, representing a 159% increase compared to pure CuGaTe2.

2.
Altern Ther Health Med ; 30(1): 58-62, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37773673

RESUMEN

Objective: The objective of this experiment was to investigate the relationship between the circadian rhythm of blood pressure and left ventricular hypertrophy (LVH) in patients with hypertension. Methods: A total of 500 hypertension patients with documented circadian rhythm of blood pressure were selected for this study. The researchers collected general patient data and fasting blood samples. The following parameters were measured within subgroups of hypertensive patients: age, sex ratio, BMI, fasting blood glucose, total cholesterol, triacylglycerol, HDL-C, LDL-C, duration of hypertension, antihypertensive drug usage, and statin intake. Results: The results of the study showed that LVH hypertension had a significantly higher proportion of grade 3 hypertension compared to non-LVH hypertension (P < .001). Additionally, LVH hypertension displayed higher mean systolic blood pressure levels over a 24-hour period (P = .002), during daytime (P = .029), and during nighttime (P < .001). The 24-hour pulse pressure (P < .001) and pulse pressure index (P = 0.001) were also significantly higher in patients with LVH hypertension. Furthermore, the rate of blood pressure decline at night was significantly lower in the LVH hypertension group compared to the control group (P < .001). B-type natriuretic peptide (BNP) levels (P = .034) and left ventricular mass index (LVMI) (P < .001) were significantly higher in patients with LVH hypertension compared to non-LVH patients. Conclusions: The findings of this study suggest a close association between hypertensive LVH and the weakening or disappearance of the circadian rhythm of blood pressure. It was also observed that the level of blood pressure classification and plasma BNP levels were increased in patients with LVH hypertension.


Asunto(s)
Hipertensión , Hipertrofia Ventricular Izquierda , Humanos , Presión Sanguínea , Hipertensión/complicaciones , Antihipertensivos/uso terapéutico , Ritmo Circadiano
3.
ACS Appl Mater Interfaces ; 15(46): 53594-53603, 2023 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-37948678

RESUMEN

Mg3Sb2-based thermoelectric materials can convert heat and electricity into each other, making them a promising class of environmentally friendly materials. Further improving the electrical performance while effectively reducing the thermal conductivity is a crucial issue. In this paper, under the guidance of the oneness principle calculation, we designed a thermoelectric Zintl phase based on Mg3.2Sb1.5Bi0.5 doped with Tb and Er. Calculation results show that using Tb and Er as cationic site dopants effectively improves the electrical properties and reduces the lattice thermal conductivity. Experimental results confirmed the effectiveness of codoping and effectively enhanced thermoelectric performance. The most immense ZT value obtained by the Mg3.185Tb0.01Er0.005Sb1.5Bi0.5 sample was 1.71. In addition, the average Young's modulus of the Mg3.185Tb0.01Er0.005Sb1.5Bi0.5 sample is 51.85 GPa, and the Vickers hardness is 0.99 GPa. Under the same test environment, the material was subjected to 12 cycles in the temperature range of 323-723 K, and the average power factor error range was 1.8% to 2.1%, which is of practical significance for its application in actual device scenarios.

4.
Behav Sci (Basel) ; 13(2)2023 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-36829308

RESUMEN

Improving the brand value of agricultural cultural heritage can promote the development of the local social economy. Meanwhile, cultural memory and brand value are inseparable. Therefore, this study took the Anxi Tieguanyin Tea Culture System as the research object, collected 679 questionnaires, adopted a structural equation model, and applied SPSS 26.0 and Amos 24.0 software (IBM; Armonk, NY, USA) to study the influence of agricultural heritage cultural memory on brand value. This study innovatively develops a scale of agricultural heritage cultural memory, enriches the outer edge of cultural memory theory research, broadens the vision of agricultural heritage research, and provides a useful reference for the inheritance of agricultural heritage and the promotion of brand value.

5.
Front Psychol ; 13: 954299, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36160530

RESUMEN

This study introduces destination image, nostalgic feeling, and flow experience into tea estate tourism and constructs a theoretical model that includes destination image, nostalgic feeling, flow experience, cultural identity, and tourists' behavioral intention. Then, an empirical study is conducted with tourists at Yunling Tea Estate in Anxi, China. The results show that all hypotheses are supported except the hypothesis pertaining to the significance of the influence of flow experience on behavioral intention, which is not supported. The model includes eight mediating effects and one moderating effect that is influenced by cultural memory.

6.
Front Psychol ; 13: 813708, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35572281

RESUMEN

The purpose of this study is to explore why workplace deviance behavior among employees has increased during Corona Virus Disease 2019 (COVID-19) from the perspective of insecure attachment style. Based on attachment theory, we propose and test the effect of insecure attachment style (attachment anxiety, attachment avoidance) on deviance behavior (organizational deviance behavior, interpersonal deviance behavior) via organization-based self-esteem using 422 data from Chinese employees. And we further examine the moderating role of leader-member exchange in reducing workplace deviance behavior. The findings show that attachment anxiety and attachment avoidance are both positively related to workplace deviance behavior. Attachment anxiety and attachment avoidance both indirectly predict organizational deviance behavior through organization-based self-esteem. Moreover, leader-member exchange can moderate the indirect effects of both attachment anxiety and attachment avoidance on organizational deviance behavior via organization-based self-esteem. This research highlights the fact that employees with insecure attachment style need more care from the organization during the COVID-19 pandemic and demonstrates that one of the key ways in which insecure attachment style increases organization-based self-esteem is by facilitating the development of high-quality leader-member exchange.

7.
ACS Omega ; 6(29): 19212-19221, 2021 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-34337259

RESUMEN

Vacancy defects are inherent point defects in materials. In this study, we investigate the role of Fe vacancy (VFe) and S vacancy (VS) in the interaction (adsorption, dissociation, and diffusion) between H2S and the FeS(001) surface using the dispersion-corrected density functional theory (DFT-D2) method. VFe promotes the dissociation of H2S but slightly hinders the dissociation of HS. Compared with the perfect surface (2.08 and 1.15 eV), the dissociation energy barrier of H2S is reduced to 1.56 eV, and HS is increased to 1.25 eV. Meanwhile, S vacancy (VS) significantly facilitates the adsorption and dissociation of H2S, which not only reduces the dissociation energy barriers of H2S and HS to 0.07 and 0.11 eV, respectively, but also changes the dissociation process of H2S from an endothermic process to a spontaneous exothermic one. Furthermore, VFe can promote the hydrogen (H) diffusion process from the surface into the matrix and reduce the energy barrier of the rate-limiting step from 1.12 to 0.26 eV. But it is very hard for H atoms gathered around VS to diffuse into the matrix, especially the energy barrier of the rate-limiting step increases to 1.89 eV. Finally, we propose that VS on the FeS(001) surface is intensely difficult to form and exist in the actual environment through the calculation results.

8.
ACS Omega ; 6(22): 14701-14712, 2021 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-34124492

RESUMEN

In the actual environment, impurity atoms significantly affect the adsorption/dissociation of gas molecules on the substrate surface and in turn promote or impede the formation of subsequent products. In this study, we investigate the effects of three kinds of impurity atoms (H, O, and S) on the adsorption/dissociation of hydrogen sulfide (H2S) and hydrogen (H) diffusion processes by using the density functional theory method. We found that impurity atoms can change the charge density distribution of the surface and thus affect the adsorption/dissociation process of H2S. The existence of a H atom reduces the dissociation barrier of H2S. The adsorption site of H2S near the O atom is transferred from the bridge site to the adjacent top site and the first-order dissociation barrier of H2S is 0.07 eV, which is prominently lower than that of the pristine surface (0.28 eV). The presence of a S atom transfers the adsorption site of H2S to a farther bridge site and effectively affects the dissociation process of H2S. Both O and S atoms hinder the dissociation process of HS. Moreover, the diffusion process of H atoms to the subsurface can be slightly impeded by the O atom. Our work theoretically explains the influence mechanism of impurity atoms on the adsorption/dissociation of H2S and H diffusion behavior on the Fe(100) surface.

9.
Biomicrofluidics ; 14(2): 024106, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32231760

RESUMEN

In many research studies and applications about microscale biochemical analysis, the generation of stable, spatiotemporally controllable concentration gradients is critical and challenging. However, precise adjustment of concentration gradients in microchannels is still a huge challenge. Because of its precise controllability, non-harmfulness, and immediacy, sound waves perfectly meet the needs of this type of problem. Utilizing the acoustofluidic platform to manipulate liquids in the microchannel accurately makes it an excellent solution to this problem. In this work, we present a tunable and reliable acoustofluidic gradient generator, which can trigger a change of medium based on acoustic streaming induced by C-shaped interdigital transducers (IDTs). By locally generating streaming via two C-shaped IDTs in the same direction but at different horizontal positions, concentration generators can produce two streams of liquids step by step, forming a stable and controllable concentration gradient within short response times (approximately second response time). Along with this gradient generator's advantages in size, tunability, and reliability, it could be widely used for micro-biological and micro-chemical applications requiring a precise concentration gradient.

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