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A novel electrocatalyst derived from a unique 3D hierarchical network of 2D Fe-doped NiSe nanosheets and CNTs on carbon paper exhibits enhanced OER performance with an overpotential of 282.0 mV to reach 10 mA cm−2 in 1.0 M KOH medium.

The development of sensitive and selective sensors using facile and low-cost methods for detecting neurotransmitter molecules is a critical factor in the health care system in regard to early diagnosis. In this research, an electrocatalyst derived from Mo,Zn dual-doped CuxO nanocrystals-based layer coating over one-dimensional copper nanowire arrays (Mo,Zn-CuxO/CuNWs) was successfully designed using a facile electrodeposition approach and used as an electrochemical sensor for non-enzymatic dopamine (DA) neurotransmitter detection. The synergistic effect caused by the dual-doping effect along with its excellent conductivity produced a large electroactive surface area and an improved hetero-charge transfer, thereby boosting DA sensing ability with a low limit detection of 0.32 µM, wide-range of detection (0.5 µM − 3.9 mM), long-term stability (5 weeks), and high selectivity in phosphate buffer solution (pH 7.4). Also, the sensor accurately determined DA in real blood serum-spiked solutions. The achieved results evidenced that the Mo,Zn-CuxO/CuNWs derived sensor is highly suitable for DA detection. Therefore, it also opens new windows for the development of low-cost, accurate, high-performance, and stable sensors for other neurotransmitter sensing for the purposes of better health care and early diagnosis.

A bifunctional electrocatalyst based on heteroatoms doped VS2 was developed for electrocatalytic water splitting.

Nowadays, Robots are widely applied in life as well as industrial production, medicine, rescue, learning and entertainment. There are many types of robots using different modern technologies that are divided into groups such as Robot Manipulator, Movement Robot, Biomimetic robot, each type is applied according to its own role. Robots are also applied in training, especially in STEM training. In this paper, we propose technical models to design Mobile Robot combined with Android OS Tablet with user interaction screen, voice control model and AIDL IPC interactive model for remote control. Mobile Robot's motion as well as giving a layered UML Model for motion handling towards open source. We research the Mobile Robot using RockChip AI Processor RK3399Pro, which focuses on understanding the structure and operating mechanism of the AI Processor that RockChip Robot uses, along with researching Android with IPC AIDL architecture and with Automatic Voice Recognition technology to control Robot to turn left, turn right, move forward, backward, jump or stop motion by voice with three languages: Korean, English and Vietnamese. From there, it will serve as a foundation for the research and development of a system to support students in learning by interacting with robots through voice in the form of gamification of the curriculum, especially for extensive research on training programs, created in the STEM field.

In this study, we prepared a three-dimensional self-supported electrocatalyst based on a thin layer of cerium oxide nanocrystals doped with cobalt heteroatoms (CeO2-Co) and then uniformly shelled over one-dimensional tin oxide (SnO2) nanorods supported by carbon cloth substrate. The material was used as a binder-free sensor that could nonenzymatically detect xanthine (XA) with an excellent sensitivity of 3.56 μA μM−1, wide linear range of 25 nM to 55 µM, low detection limit of 58 nM, and good selectivity. A screen-printed electrode based on the material accurately detected XA in food samples as well. The achievements were resulted from synergistic effects coming from the unique core@shell formation and Co-doping strategy, which efficiently modified electronic structure of the material to expose more electroactive site numbers/types and fast charge transfer, thereby producing intrinsic catalytic properties for XA oxidation. These results suggested that the SnO2@CeO2-Co is potential for developing efficient sensor to detect XA with good sensitivity and accuracy in food-quality monitoring.

A novel sulfur-doped vanadium-molybdenum oxide nanolayer shelling over two-dimensional cobalt nanosheets (2D Co@S-VMoOx NSs) was synthesized via a facile approach. The formation of such a unique 2D core@shell structure together with unusual sulfur doping effect increased the electrochemically active surface area and provided excellent electric conductivity, thereby boosting the activities for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). As a result, only low overpotentials of 73 and 274 mV were required to achieve a current response of 10 mA cm-2 toward HER and OER, respectively. Using the 2D Co@S-VMoOx NSs on nickel foam as both cathode and anode electrode, the fabricated electrolyzer showed superior performance with a small cell voltage of 1.55 V at 10 mA cm-2 and excellent stability. These results suggested that the 2D Co@S-VMoOx NSs material might be a potential bifunctional catalyst for green hydrogen production via electrochemical water splitting.

For flexible displays, there is a desperate need for a broadband coatable polarizer that can absorb light in a specific direction. Conventional polarizers fabricated by the polymer stretching process are too thick (50-200 μm) to be used as polarizers that can be applied to antireflective films in flexible displays. For the development of the broadband coatable thin film polarizer, diacetylene (DA) amphiphiles containing I- or I3- are newly designed and synthesized, and the content of DA amphiphiles in the 4,6-decadiyne solvent is optimized to form a lyotropic liquid crystal (LLC) phase. Topochemical polymerization of uniaxially oriented iodine-based DA not only stabilizes the film but also broadens the polarization light region from 350 to 700 nm. The transfer and amplification of iodine and DA functions in uniaxially oriented thin films enable the fabrication of broadband coatable thin film polarizers.

Utilizing a newly programmed and synthesized heat storage mesogen (HSM) and reactive mesogen (RM), advanced heat managing polymer alloys that exhibit high thermal conductivity, high latent heat, and phase transition at high temperatures were developed for use as smart thermal energy harvesting and reutilization materials. The RM in the heat-managing RM-HSM polymer alloy was polymerized to form a robust polymeric network with high thermal conductivity. The phase-separated HSM domains between RM polymeric networks absorbed and released a lot of thermal energy in response to changes in the surrounding temperature. For the fabrication of smart heat-managing RM-HSM polymer alloys, the composition and polymerization temperature were optimized based on the constructed phase diagram and thermal energy managing properties of the RM-HSM mixture. From morphological investigation and thermal analysis, it was realized that the heat storage capacity of polymer alloys depends on the size of the phase-separated HSM domain. The structure-morphology-property relationship of the heat managing polymer alloys was built based on the combined techniques of thermal, scattering, and morphological analysis. The newly developed mesogen-based polymer alloys can be used as smart thermal energy-harvesting and reutilization materials.

The development of a rapid, selective, and sensitive sensor to precisely monitor nitrite oxidation is of growing importance, given the strong interest in the protection of drinking water quality, treatment of wastewater, food production, and control of remediation processes. In this research, we successfully fabricated a hybrid originated from worm-like gold nanowires (Au WNWs) assembled on a high-quality carbon nanofibers-graphene (CNFs–Gr) hybrid network through a facile synthesis method. The hybrid as a binder-free sensor exhibited excellent activity towards nitrite detection in phosphate buffer solution (pH of 7.4) with a wide linear detection range of (1.98 µM – 3.77 mM), excellent sensitivity of 836 μA cm−2 mM−1, low detection limit of 1.24 µM, and long-term durability. The results were attributed to a special synergistic effect originating from unique hybridization of Au WNWs with large-area CNFs–Gr network to produce more electroactive sites and excellent conductivity, favorably boosting catalytic performance of the sensor. The successful fabrication of Au WNWs/CNFs–Gr suggested an interesting candidate for practically determining low-level nitrite in analytical applications.

ASEAN has become an influential center of interaction among Asia-Pacific countries in today's world, successfully addressing various issues of economic and social interaction. Today, ASEAN effectively promotes multilateral cooperation and plays an important role in ensuring and maintaining peace and security in the region. Vietnam is one of the leaders of the Association, representing one of the fastest growing economies in the region. Modern Vietnam participates in all programs of the Association, actively developing cooperation and solidarity within the Association. As a strategic partner of Russia, Vietnam has played an important role in the development of relations between Russia and the Association.

With the significance of heat management, recently, high thermal conducting polymers have attracted attention as promising polymeric matrix materials in miniaturized and flexible devices. Porphyrin-based reactive metallomesogens (PorV-x; x = -2H, -Ni, -Cu, and -Zn) were newly designed and synthesized for the fabrication of thermal conducting polymers. Self-assembled and subsequently polymerized PorV-x films exhibited excellent mechanical, chemical, and thermal stability. The thermal conducting properties of PorV-x films can be adjusted as desired by controlling the molecular planarity through metal core substitution. From the results of systematic experiments, it was realized that a deep understanding of the correlation between the supramolecular packing structure and thermal properties is essential for the precise control of the heat dissipating performance in advanced heat managing materials.

The development of highly efficient electrocatalysts for simultaneous evolution of hydrogen and oxygen is a vital concern in water splitting. In this study, a novel catalyst derived from a porous interconnected network of nickel cobalt oxysulfide interfacial assembled Cu@Cu2S nanowires was rationally designed. It was recognized that the formation of multi-integrated active centers and a higher number of active sites, together with an adjusted adsorption energy towards reactants caused by the modulated surface and crystalline distortion of the NiCo oxide layer due to S insertion synergistically promoted both HER and OER. In addition, such 3D innovative core–shell structure effectively fine-tuned conductive properties and maximized interfacial contact to improve charge/mass transfer, thereby boosting catalytic activity and durability towards hydrogen and oxygen evolution. The catalyst only required an overpotential of 203 mV to achieve a current response of 20 mA cm−2 for the HER and 295 mV to reach 50 mA cm−2 for the OER in 1.0 M KOH medium. A developed electrolyzer enabled a small cell voltage of 1.61 V at 20 mA cm−2 without performance decay upon long-term operation. This result suggested an exciting prospect for developing new bifunctional electrocatalysts, which could effectively accelerate both hydrogen and oxygen evolution for water splitting applications.

Water splitting via the use of an efficient catalyst is a clean and cost-effective approach to produce green hydrogen. In this study, we successfully developed a novel hybrid coming from thin NiO-NiSe

The flexible electrochromic Zn-ion battery (FE-ZiB), a newly born energy-storage technology having both electrochromic characteristics and energy-storage capability in a single device, will be a promising technology for the future transparent wearable electronics. However, the current technology limits the fabrication of FE-ZIB because the zinc (Zn) anode material is opaque and rigid. The development of a flexible and transparent Zn anode is the key factor to overcoming the current limitation. Here, for the first time, a flexible, transparent zinc-nanofiber network anode electrode (Zn@Ni@AgNFs) is reported for an FE-ZiB device that yields a remarkable electrochemical performance of a high areal capacity of 174.82 mA h m2 at 0.013 mA cm-2 applied current density, high optical contrast (50%), and excellent mechanical flexibility. The fabricated FE-ZiB device also exhibits a high volumetric energy density of 378.8 W h m-3 at a power density of 562.7 W m-3 . Besides, the FE-ZiB demonstrates excellent electrochromic capability with a reversible color transition from a transparent in a discharged state (0.3 V) to a dark bluish-violet in a charged state (1.6 V). These results highlight a new pathway for the development of transparent batteries for smart wearable electronic devices.

A novel sulfur-doped vanadium-molybdenum oxide nanolayer shelling over two-dimensional cobalt nanosheets (2D Co@S-VMoO

The development of sensitive and selective sensors using facile and low-cost methods for detecting neurotransmitter molecules is a critical factor in the health care system in regard to early diagnosis. In this research, an electrocatalyst derived from Mo,Zn dual-doped Cu

Due to the easy recyclability and pollution-free nature of hydrogen fuel, its highly purified production through electrochemical water splitting process has been attracting increasing attention. In this work, a hybrid of hierarchical porous nickel–cobalt phosphide nanoneedle arrays supported micro-carbon spheres was successfully synthesized and employed as robust bifunctional electrocatalyst for overall water splitting. The optimized Ni1Co3–P@CSs displayed catalytic activity with a low overpotential (η) of 57 mV at 10 mA cm−2 for hydrogen evolution and a η of 330 mV at 20 mA cm−2 for oxygen evolution, along with good stability after testing for 30 h. The water splitting cell of the Ni1Co3–P@CSs delivered smaller cell voltage at a current density of 50 mA cm−2 and much better durability than a similar device based on RuO2/C and Pt/C. The enhanced performance was assumed to the unique hierarchical three-dimensional urchin nanostructure of bimetallic phosphide nanoneedles, which resulted in the synergetic effects to modulate electronic properties and electroactive surface area. These improved the reactant's intermediates adsorption energy, number of exposed active sites, and various shortened channels for charge transfer and reactant/electrolyte diffusion. Our finding offers an attractive electrocatalyst with low cost and high catalytic activity for efficient water electrolysis.

The fabrication of low-cost, highly efficient, and earth-abundant electrocatalysts for oxygen reduction reaction is critical to produce clean and sustainable fuel through an electrochemical process. Herein, a facile hydrothermal technique is used for the synthesis of iron sulfide/graphene hybrid for oxygen reduction reaction. Morphological analysis of the resulting catalyst reveals that iron sulfide nanoparticles are homogeneously embedded on the surface of reduced graphene oxide sheet. Electrochemical analysis of the hybrid exhibits remarkably improved catalytic performance for oxygen reduction reaction while achieving half wave potential of +0.845 V and onset potential of +1.0 V (versus reversible hydrogen electrode), along with outstanding long-term stability under alkaline conditions. In addition, the methanol tolerance ability and stability of the hybrid exceed the benchmark platinum/carbon product in alkaline condition. These outstanding activities of the hybrid are attributed to the merits of the interaction between iron sulfide nanoparticles and graphene. The results suggest the practicability of metal sulfide as a low cost and efficient alternative catalyst of platinum for oxygen reduction reaction.

The design of low-cost, highly efficient, and the durable catalyst is essential to replace commercial platinum metal-based catalysts for the oxygen reduction reaction (ORR) in fuel cell applications. Herein, a novel mesoporous hybrid based on nitrogen-doped graphene nanosheets-stabilized layered spinel zinc manganese oxide (Zn2Mn3O8-NG) is successfully engineered and applied as an effective catalyst to accelerate the ORR process in alkaline medium. Electrochemical performance analysis of this catalyst shows excellent catalytic activity with high current density, positive onset potential (−0.013 V), and positive half-wave potential (−0.12 V), which are relative to the commercial Pt/C in 0.1 M KOH electrolyte. The kinetic study of the synthesized catalyst towards ORR demonstrates a direct 4e− transfer pathway. The methanol tolerance and long-term stability test suggest its superior behavior to Pt/C. The excellent performance of the Zn2Mn3O8-NG is attributed to the synergistic effects of nanosized Zn2Mn3O8 nanocrystals and NG nanosheets, which effectively improve the electroactive surface area, conductivity, diffusion channels, and mass transfer ability. This result suggests that the resulting catalyst could be used as a potential alternative of Pt-based catalysts towards ORR application.

A Pt nanodots monolayer with ultra-low surface loading of 0.48 at% integrating onto a mesoporous complex nanostructure of Cu@CuxO nanowires (NWs) supported by a three-dimensional substrate is developed via a versatile and effective deposition strategy of the galvanic displacement between Cu monolayer and PtCl42- in an effort to minimize Pt catalyst usage. The uniform and ultra-small Pt nanodots (∼2 nm) achieved full coverage on NWs leads to significant structural modulation, along with increased hierarchical and disorder degree. It also generates high Pt-Cu interaction, as evidenced by the crystal lattice deformation of metallic phases and the charge transfer from Cu to Pt, leading to enhancement towards both of hydrogen evolution (HER) and oxygen evolution (OER) processes. The hybrid exhibits low overpotential values of 72 mV and 250 mV at 10 mA cm−2 for HER and OER, respectively, and these are superior to those of other surveyed materials. The mass activity of hybrid is around 3.1 times higher than commercial Pt-C (10 wt%) for HER and 6.4 times higher than Pt-C and RuO2-C for OER under similar testing conditions. This research may serve as a promising method for developing electrocatalysts with high activity but minimal Pt usage towards water splitting.

Developing efficient and cost-effective bifunctional electrocatalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is highly important for fabricating energy conversion and storage technologies, such as fuel cells, water electrolyzers, and metal–air batteries. Herein, we report a facile and economical route for synthesizing ultrasmall molybdenum phosphide (MoPy) nanocrystal-attached mesoporous manganese phosphides on N,P-codoped graphene nanosheets, which display equivalent ORR (OER) activity to that of Pt/C (RuO2) catalysts. This is manifested by the positive onset potential (0.969 V) and half-wave potential (0.842 V) for ORR, as well as a mere overpotential of 301 mV at a current density of 20 mA·cm–2 and a small Tafel slope of 105 mV·dec–1 for OER in alkaline medium. It also demonstrates remarkable stability in comparison with Pt/C and RuO2 for both ORR and OER, respectively. The excellent performance can be attributed to the mesoporous structure with enhanced multiple t...

In an attempt to find an alternative approach to reduce the use of noble metal-based electrocatalysts, a new hybrid nanostructure based on molybdenum-iron nitride nanoparticles (Mo–Fe–N NPs) deposited carbon nanotubes (CNTs) supported on nickel foam substrate is fabricated via a facile synthetic approach. Highly uniform and dense Mo–Fe–N NPs achieves full coverage on surface of the CNTs with good interactions and enhanced hetero-charge transfer, thus leading to improvements in both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). The fabricated hybrid shows small overpotential of 106 mV at 10 mA cm−2 for HER and 420 mV at 100 mA cm−2 for OER, along with prospective stability after 20 h of continuous testing in alkaline electrolyte (1.0 M KOH). The catalytic activities of the Mo–Fe–N/CNTs material are shown to be superior to those of other synthesized catalysts as well as of commercial Pt/C and RuO2 catalysts. These results may pave a potential route to the fabrication of novel electrocatalysts having high performance that can effectively replace precious metal-based catalysts in electrochemical water splitting technology.

A series of diketopyrrolopyrrole (DPP) luminogen amphiphiles were newly designed and synthesized by a single-step anionic exchange reaction for controlling the photoluminescence properties in both solution and solid states. Multicolor emission in response to thermal, mechanical, and chemical stimuli was successfully demonstrated by engineering well-defined supramolecular assemblies. Phase transformation from the metastable amorphous solid to the stable orthorhombic crystal of [DP-Im][Br] provided the reversibly patternable light emission. Self-organization into the smectic crystalline phase of [DP-Im][TFSI] allowed us to show the linearly polarized light emission. By simultaneously applying [DP-Im][Br] and [DP-Im][TFSI], we demonstrated the fabrication of smart sensors for packaging of food or vaccines that can detect thermal attacks.

In this study, we prepared a three-dimensional self-supported electrocatalyst based on a thin layer of cerium oxide nanocrystals doped with cobalt heteroatoms (CeO