Precision Target Guide Strategy for Applying SERS into Environmental Monitoring

Surface enhanced Raman spectroscopy (SERS) is a promising analytical technique that exhibits various applications in trace detection and identification. When it is applied into environmental monitoring, we should concern several key points to improve detection sensitivity and selectivity for the detection in complex matrix. In this tutorial review, we mainly focus on the strategies for improving the use of SERS into environmental application. The strategies are summarized for enhancing the ability of the substrate to selectively capture specific targets, and for achieving separation and concentration of the analytes from the matrix and the assembly structures for multiple phase detection. We have also introduced several newly developed detection systems using portable instruments and miniaturized devices that are more suitable for infield applications. In addition, we discuss the present challenges that hide it from wide real application and give the outlook for the future development in applying SERS in environmental monitoring

Sum-Rate Maximization for Movable Antenna Enabled Multiuser Communications

A novel multiuser communication system with movable antennas (MAs) is proposed, where the antenna position optimization is exploited to enhance the downlink sum-rate. The joint optimization of the transmit beamforming vector and transmit MA positions is studied for a multiuser multiple-input single-input system. An efficient algorithm is proposed to tackle the formulated non-convex problem via capitalizing on fractional programming, alternating optimization, and gradient descent methods. To strike a better performance-complexity trade-off, a zero-forcing beamforming-based design is also proposed as an alternative. Numerical investigations are presented to verify the efficiency of the proposed algorithms and their superior performance compared with the benchmark relying on conventional fixed-position antennas (FPAs).Comment: 11 page

Phonon-lithium ion interactions: A case study of LiM(SeO3)2

Li ion diffusion is fundamentally a thermally activated ion hopping process. Recently, soft lattice, anharmonic phonon and paddlewheel mechanism have been proposed to potentially benefit the ion transport, while the understanding of vibrational couplings of mobile ion and anions is still limited but essential. Herein, we access the ionic conductivity, the stability and the lattice dynamics in LiM(SeO3)2 (M =Al, Ga, In, Sc, Y, and La) with two types of oxygen anions within LiO4 polyhedron, namely edge-shared and corner-shared, the prototype of which, LiGa(SeO3)2, has been experimentally synthesized. We studied in detail the anharmonic and harmonic phonon interactions, as well as couplings between vibrations of edge-bonded or corner-bonded anions in Li polyanions and Li ion diffusion. As M changing from Sc to La, anharmonic phonons increase alongside reduced activation energy for Li diffusion. Phonon modes involving edge-bonded oxygen anions contribute more to Li migration than corner-bonded oxygen anions, owing to greater atomic interactions between Li ions and edge-bonded anions. Thus, rather than the overall lattice softness, attentions shall be paid to reduce the frequency of the critical phonons contributing to Li ion diffusions as well as to increase the anharmonicity, for the design of Li ion superionic conductors for all-solid-state-batteries

Trajectory optimization of unmanned aerial vehicle in dynamic soaring

An aircraft can extract energy from a gradient wind field by dynamic soaring. The paper presents trajectory optimization of an unmanned aerial vehicle for dynamic soaring by numerical analysis and validates the theoretical work through flight test. The collocation approach is used to convert the trajectory optimization problem into parameters optimization. The control and state parameters include lift coefficient, bank angle, positions, flight path angle, heading angle, and airspeed, which are obtained from the parameter optimization software. To validate the results of numerical simulation, the dynamic soaring experiment is also performed and experimental data are analyzed. This research work shows that the unmanned aerial vehicle can gain enough flight energy from the gradient wind field by following an optimal dynamic soaring trajectory. Meanwhile, the variation of flight path angle, heading angle, and airspeed has a significant influence on the energy transform. The solution can provide theoretical guide to unmanned aerial vehicles for extracting maximum energy from gradient wind fields. </jats:p

Spatial separation of anaerobic ammonium oxidation and nitrite-dependent anaerobic methane oxidation in permeable riverbeds.

Anaerobic ammonium oxidation (anammox) and nitrite-dependent anaerobic methane oxidation (n-damo) play important roles in nitrogen and carbon cycling in fresh waters but we do not know how these two processes compete for their common electron acceptor, nitrite. Here, we investigated the spatial distribution of anammox and n-damo across a range of permeable riverbed sediments. Anammox activity and gene abundance were detected in both gravel and sandy riverbeds and showed a simple, common vertical distribution pattern, while the patterns in n-damo were more complex and n-damo activity was confined to the more reduced, sandy riverbeds. Anammox was most active in surficial sediment (0-2cm), coincident with a peak in hzsA gene abundance and nitrite. In contrast, n-damo activity peaked deeper down (4-8cm) in the sandy riverbeds, coincident with a peak in n-damo 16S rRNA gene abundance and higher methane concentration. Pore water nitrite, methane and oxygen were key factors influencing the distribution of these two processes in permeable riverbeds. Furthermore, both anammox- and n-damo- activity were positively correlated with denitrification activity, suggesting a role for denitrification in supplying both processes with nitrite. Our data reveal spatial separation between anammox and n-damo in permeable riverbed sediments that potentially avoids them competing for nitrite. This article is protected by copyright. All rights reserved

How Design Thinking Could Benefit Future Educational Environments in a Post-Pandemic Era?

This research paper gives an overview of students’ experience in a virtual learning context during the Covid-19 pandemic lockdown. By categorising students’ perceptions based on a geographic-based social context, the research analyses a general tendency of their learning experience at three different levels — family and community-based level (small-sized), region-based level (medium-sized), and international level (grand-sized). The investigation uses a hybrid research method including direct observation, interviews, and design thinking strategies — including empathising, redefining and prototyping. The author has also been referring to two directions that may enhance the future learning environment design for students’ better experience. 1. To leverage the power of existing memory. 2. To research people’s micro habits and the hidden psychological factor behind them

2-(4-Bromo­phen­yl)-N-(2-methoxy­phen­yl)acetamide

In the title compound, C15H14BrNO2, the 4-bromo­phenyl fragment makes a dihedral angle of 76.55 (17)° with the acetamide unit and the dihedral angle between the two benzene rings is 50.88 (14)°. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds and C—H⋯π contacts connect the mol­ecules, forming chains propagating in [100]