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Abstract Marxism-Leninism has become a widespread ideological foundation that is consistently and firmly pursued by the Communist Party of Vietnam (CPV) in its leadership orientation for national development. This research aims to explore and identify the distinctive issues in Friedrich Engels’ theoretical thinking regarding the formation of theoretical thinking based on practical experience, the close relationship between theoretical and scientific thinking, materialist dialectical thinking and mastering the scientific principles of philosophy. These orientations have become methodological guides for the CPV to apply to its leadership activities. This research was conducted based on the analysis and synthesis of available sources, with the main sources being the Marx-Engels Collected Works and some classical works written independently by Friedrich Engels, along with a synthesis of related studies. The results indicate that Friedrich Engels’ theoretical thinking has been studied, supplemented, developed, and creatively applied by the Communist Party of Vietnam in the renovation process in Vietnam, especially since the CPV initiated the renovation policy in December 1986. To date, Vietnamese socialist theory continues to be supplemented by Friedrich Engels’ theoretical thinking, which in his time had not been able to be experimented, contributing significantly to the development of the CPV’s theoretical understanding of political, economic, cultural, and social leadership, becoming an important guiding tool for the CPV to firmly lead the implementation of the renovation policy. Friedrich Engels’ theoretical thinking also holds important value in the struggle against erroneous, eclectic, dogmatic, and mechanical views on human perception and practical action.

The thermoelectric performance of SnSe strongly depends on its low-energy electron band structure that provides high density of states in a narrow energy window due to the multi-valley valence band maximum (VBM). Angle-resolved photoemission spectroscopy measurements, in conjunction with first-principles calculations, reveal that the binding energy of the VBM of SnSe is tuned by the population of Sn vacancy, which is determined by the cooling rate during the sample growth. The VBM shift follows precisely the behavior of the thermoelectric power factor, while the effective mass is barely modified upon changing the population of Sn vacancies. These findings indicate that the low-energy electron band structure is closely correlated with the high thermoelectric performance of hole-doped SnSe, providing a viable route toward engineering the intrinsic defect-induced thermoelectric performance via the sample growth condition without an additional ex-situ process.

In this study, we successfully synthesized europium-doped TiO2(TiO2:Eu3+) nanomaterials (NMs) with crystalline sizes ranging from 6.5 to 71.7 nm through a sol-gel method. Analysis of X-ray diffraction (XRD) patterns and ultraviolet-visible (UV-Vis) spectra indicates that the substitution of smaller-sized Ti4+ ions (0.745 Å) by largersized Eu3+ ions (0.947 Å) was more efficient at higher doping concentrations and annealing temperatures. Photoluminescence (PL) and photoluminescence excitation (PLE) spectra of the synthesized TiO2:7%Eu3+ NMs exhibit a strong red emission band peaking at 613 nm and remarkable absorption in the blue light region centered at 463 nm, making them suitable for use in white light-emitting diode (WLED) applications. Our findings reveal that both annealing temperature and doping concentration significantly influence the structure and properties of these materials. Besides, the research team has seen, under the experimental conditions, the TiO2:7%Eu3+ sample annealed at 800°C exhibits the highest PL intensity. These results underscore the potential of the synthesized TiO2:Eu3+ NMs as red-emitting materials for WLED applications.

Abstract Natural disasters in the Central Highlands of Vietnam are increasing and therefore becoming a concern for the provincial governments. The local authorities’ recent ability to respond to natural disasters in the region is considered ineffective, as evidenced by the increasing number of deaths and economic losses. Here, we focus on presenting and analyzing the current capacity of local authorities in the Central Highlands of Vietnam to respond to natural disasters in a normal state and in transitioning to an emergency state. We also provide evidence of natural disasters that have occurred and the actions undertaken by the Central Highlands provinces over the period 2015–2021. Our analysis shows that the capacity of local authorities to respond to natural disasters in the region is not commensurate with the actual requirements, in the dry season, the drought area increases, in the rainy season floods occur more, and human losses and economic losses have not been controlled. We propose that first of all, the government needs to have a system of timely guidance documents, the coordination between relevant agencies, secondly, that civil servants working in disaster response work must be capable, thirdly, the government must there should be publicity on how to respond, four is to limit the hot growth of projects such as hydroelectric projects, five is that the government must have a long-term master plan and sixth is to pay attention to livelihoods, education level of local ethnic people. These proposals can gradually control and limit the damage caused by increasingly severe natural disasters in the Central Highlands.

Abstract This analysis explores the relationship between transformational, transactional, and laissez-faire leadership styles with staff work engagement at the department level in the public sector in Vietnam. Using a cluster sampling method, a total of 378 participants were selected and agreed to participate in a survey by completing a questionnaire on the relationship between leadership style and work engagement. All participants are attendees of a training course for department-level leaders at the School of Culture, Sports, and Tourism Administration Officers under the Ministry of Culture, Sports, and Tourism of Vietnam. A regression was run on the collected data to test the hypothesis on the relationship between leadership styles and staff task performance. The regression results show that there is a significant indirect relationship between staff work engagement and innovative work behavior and task performance. In addition, there is a relatively positive relationship between the transformational leadership style and transactional leadership style of the department-level leaders in the Vietnamese public sector with staff work engagement, particularly innovative work behavior and task performance. On the contrary, laissez-faire leadership style negatively impacts staff work engagement and innovative work behavior. Staff work engagement is an integral part of the relationship between leadership style and leadership effectiveness. The findings suggest that the Vietnamese public sector should aim to identify transformational and transactional leaders. This research focuses on the department level and is limited to three leadership styles (transformational, transactional, and laissez-faire) only. Future research therefore can expand the scope to higher levels than the department leaders.

This paper studies the liquid Nano-droplet production ability using molecular dynamics simulation methodology. The research parameter is performed at the temperature of 310 Kelvin (K), the pressing force of 10.0 × 10−10 Newton (N) and the ejective hole diameters of 25 and 40 Angstrom (Å). The research result shows that liquid Nano-droplets finally were not produced for the ejective diameter of 25 Å. The Nano-jets were not only non-destruction from nozzle’s surface to produce the droplets but also movement downward to come back the nozzle’s surface. The molecular trajectory is very zigzag and curved both inside and outside the ejective container. In the contrary, when increasing the ejective diameter to 40 Å, the liquid Nano-droplet was produced in the same the ejective time and compressible force magnitude. The molecular trajectory is quite straight after ejecting out the outside of the container. Meanwhile, for the nozzle diameter size of 40 Å, the Nano-droplet was not only production but also movement up to leave away the nozzle’s surface under same above conditions. That proves that the ejective diameter has the influences to the moveable direction and Nano-droplets formation ability in the whole ejective process.

Manipulating the grain boundary and chiral structure of enantiomorphic inorganic thermoelectric materials facilitates a new degree of freedom for enhancing thermoelectric energy conversion. Chiral twist mechanisms evolve by the screw dislocation phenomenon in the nanostructures; however, contributions of such chiral transport have been neglected for bulk crystals. Tellurium (Te) has a chiral trigonal crystal structure, high band degeneracy, and lattice anharmonicity for high thermoelectric performance. Here, Sb‐doped Te crystals are grown to minimize the severe grain boundary effects on carrier transport and investigate the interface of chiral Te matrix and embedded achiral Sb2Te3 precipitates, which induce unusual lattice twists. The low grain boundary scattering and conformational grain restructuring provide electrical‐favorable semicoherent interfaces. This maintains high electrical conductivity leading to a twofold increase in power factor compared to polycrystal samples. The embedded Sb2Te3 precipitates concurrently enable moderate phonon scattering leading to a remarkable decrease in lattice thermal conductivity and a high dimensionless figure of merit (zT) of 1.1 at 623 K. The crystal growth and chiral atomic reorientation unravel the emerging benefits of interface engineering as a crucial contributor to effectively enhancing carrier transport and minimizing phonon propagation in thermoelectric materials. [ABSTRACT FROM AUTHOR]

Abstract Transition metal dichalcogenides have attracted renewed interest for use as thermoelectric materials owing to their tunable bandgap, moderate Seebeck coefficient, and low thermal conductivity. However, their thermoelectric parameters such as Seebeck coefficient, electrical conductivity, and thermal conductivity are interdependent, which is a drawback. Therefore, it is necessary to find a way to adjust one of these parameters without affecting the other parameters. In this study, we investigated the effect of helium ion irradiation on MoSe2 thin films with the objective of controlling the Seebeck coefficient and electrical conductivity. At the optimal irradiation dose of 1015 cm−2, we observed multiple enhancements of the power factor resulting from an increase in the electrical conductivity, with slight suppression of the Seebeck coefficient. Raman spectroscopy, X-ray diffraction, and transmission electron microscopy analyses revealed that irradiation-induced selenium vacancies played an important role in changing the thermoelectric properties of MoSe2 thin films. These results suggest that helium ion irradiation is a promising method to significantly improve the thermoelectric properties of two-dimensional transition metal dichalcogenides. Graphical Abstract Effect of He+ irradiation on thermoelectric properties of MoSe2 thin films.

The important role of local government in the socio-economic development of localities has been confirmed in many domestic and foreign studies. But the role of government in drought adaptation has often received little attention and analysis in domestic studies. Approaching from the local tectonic government model, the article argues that local government is an important link to promote adaptive capacity at the local level of Vietnam and the Central Highlands provinces provide a case study that is typical for research and development of the capacity to adapt to drought and natural disasters for local authorities in Vietnam. Analysis of adaptive capacity through case studies in local government in the Central Highlands provinces shows that capacity is a major challenge for local governments here. The paper recommends that it is necessary to further expand the initiative and role of local authorities in guiding and promoting adaptation for communities and local people. Doi: 10.28991/HEF-2021-02-02-03 Full Text: PDF