Wind Noise Mitigation via Dynamic Microphone Selection

A recent study of wind noise data suggests wind noise suppression (WNS) algorithms face the largest challenge from wind noise coming from right in front of the user. As a result, the audio quality as a result is significantly worse than all other directions. This study also shows the wind noise does not contaminate all the mics equally, due to the shape of the mic array. Assuming we have some mechanism to detect the most contaminated mics and exclude them from beamforming, the output audio would be significantly improved. Therefore, we created a strategy for an audio system to handle the most challenging case with a detector for wind noise coming from the front. Upon the detection, an audio system switches to a different subset of the microphones to apply WNS, beamforming, and further noise processing

Unveiling the additive-assisted oriented growth of perovskite crystallite for high performance light-emitting diodes.

Solution-processed metal halide perovskites have been recognized as one of the most promising semiconductors, with applications in light-emitting diodes (LEDs), solar cells and lasers. Various additives have been widely used in perovskite precursor solutions, aiming to improve the formed perovskite film quality through passivating defects and controlling the crystallinity. The additive's role of defect passivation has been intensively investigated, while a deep understanding of how additives influence the crystallization process of perovskites is lacking. Here, we reveal a general additive-assisted crystal formation pathway for FAPbI3 perovskite with vertical orientation, by tracking the chemical interaction in the precursor solution and crystallographic evolution during the film formation process. The resulting understanding motivates us to use a new additive with multi-functional groups, 2-(2-(2-Aminoethoxy)ethoxy)acetic acid, which can facilitate the orientated growth of perovskite and passivate defects, leading to perovskite layer with high crystallinity and low defect density and thereby record-high performance NIR perovskite LEDs (~800 nm emission peak, a peak external quantum efficiency of 22.2% with enhanced stability)

Synthesis and characterization of the regiorandom homopolymer of 3-alkyldithieno[3,2-b:2',3'-d]thiophene for thin-film transistors

A regiorandom homopolymer of 3-alkyldithieno[3,2-b:2[prime or minute],3[prime or minute]-d]thiophene (P3ADTT) has been prepared by oxidative polymerization using Iron(iii) Chloride and oxygen as oxidants. The physical and electrochemical properties of the homopolymer were investigated and compared with those of P3HT. Its application in organic field-effect transistors showed annealing-free hole mobility up to 0.048 cm2 V-1 s-1 at room temperature and a significant thermally stable mobility of 0.13 cm2 V-1 s-1 at 200 [degree]C with a current on/off ratio of greater than 105

Research on the Efficient Space Debris Observation Method Based on Optical Satellite Constellations

The increasing amount of space debris poses a major threat to the security of space assets. The timely acquisition of space debris orbital data through observations is essential. We established a mathematical model of optical satellite constellations for space debris observation, designed a high-quality constellation configuration, and designed a space debris tracking observation scheduling algorithm. These tools can realize the efficient networking of space debris from a large number of optical satellite observation facilities. We designed a constellation consisting of more than 20 low-Earth orbit (LEO) satellites, mainly dedicated to the observation of LEO space objects. According to the observation scheduling method, the satellite constellation can track and observe more than 93% of the targets every day, increase the frequency of orbital data updates, and provide support for the realization of orbital space debris cataloguing. Designing optical satellite constellations to observe space debris can help realize the advance perception of dangerous collisions, timely detect dangerous space events, make key observations about high-risk targets, greatly reduce the false alarm rate of collisions, and provide observational data support for space collisions

High Throughput and Acceptance Ratio Multipath Routing Algorithm in Cognitive Wireless Mesh Network

The link failure due to the secondary users exiting the licensed channels when primary users reoccupy the licensed channels is very important in cognitive wireless mesh networks (CWMNs). A multipath routing and spectrum allocation algorithm based on channel interference and reusability with Quality of Service (QoS) constraints in CWMNs (MRIR) was proposed. Maximizing the throughput and the acceptance ratio of the wireless service is the objective of the MRIR. First, a primary path of resource conservation with QoS constraints was constructed, then, a resource conservation backup path based on channel interference and reusability with QoS constraints was constructed. The MRIR algorithm contains the primary path routing and spectrum allocation algorithm, and the backup path routing and spectrum allocation algorithm. The simulation results showed that the MRIR algorithm could achieve the expected goals and could achieve a higher throughput and acceptance ratio

Machine Vision-Based Method for Measuring and Controlling the Angle of Conductive Slip Ring Brushes

The conductive slip ring is used for power or signal transmission between two objects rotating relative to each other. It has become an essential part of modern industrial development. In traditional automated production measurements, the typical method is to use calipers, goniometers, or angle gauges to measure a parameter of the workpiece several times and then average it. These inspection means have low measurement accuracy and slow measurement speed, and measurement data cannot be processed in a timely manner. A machine vision-based method for measuring and controlling the angle of the brushes is proposed for this problem. First, the brush angle forming device was built for the conductive slip ring brush wire, forming the principle and rebound characteristics. Then, machine vision and image processing algorithms were applied to measure the key parts of the conductive slip ring brushes. The data of the forming angle value and rebound angle value were obtained during the forming process of the brush wire angle. Finally, a pre-compensation model for the brush filament rebound was developed and validated based on the curve fitting method. The test results show that the error of the angle measurement is within 0.05°. The average error of the measured rebound angle and the calculated rebound angle of the brush filament pre-compensation model was 0.112°, which verifies the correctness of the pre-compensation model. The forming angle can be controlled more precisely, and the contact performance between the brush wire and the ring body can be improved effectively. This method has the potential to be extended to engineering applications

Regio- and Stereoselective Reductive Coupling of Alkynes and Crotononitrile

A new regio- and stereoselective reductive coupling of alkynes and crotononitrile has been developed via visible light organophotoredox cobalt dual catalysis. A variety of enantioenriched homoallylic nitriles bearing a stereodefined trisubstituted alkene have been easily synthesized with good to excellent regio- (up to >20:1 rr), stereo- (>20:1 E/Z), and enantioselectivity (up to 98% ee) control under mild conditions. The corresponding nitrile products were smoothly converted into various chiral building blocks. Remarkably, a simple organic base together with water have been utilized as hydrogen sources in this photoinduced reductive reaction

Occurrence and distribution characteristics of fluids in tight sandstone reservoirs in the Shilijiahan zone, northern Ordos Basin

High-yield gas layers, low-yield gas layers and (gas bearing) water layers of Upper Paleozoic coexist in the Shilijiahan zone in the northern Ordos Basin, but gas–water distribution characteristics, laws and influence factors are not understood well, so the exploration and development of natural gas in this zone are restricted. In this paper, statistical analysis was carried out on the data of Upper Paleozoic formation water in this zone, e.g. salinity, pH value and ion concentration. It is shown that the formation water in this zone is of CaCl2 type. Then, the origin, types, controlling factors and spatial distribution characteristics of formation water were figured out by using core, mud logging, well logging and testing data, combined with the classification and evaluation results of geochemical characteristics of formation water. Besides, the logging identification chart of gas, water and dry layers in this zone was established. Finally, the occurrence and distribution laws of reservoir fluids were defined. The formation water of CaCl2 type indicates a good sealing capacity in this zone, which is favorable for natural gas accumulation. It is indicated that the reservoir fluids in this zone exist in the state of free water, capillary water and irreducible water. Free water is mainly distributed in the west of this zone, irreducible water in the east, and capillary water in the whole zone. The logging identification chart has been applied in many wells in this zone like Well Jin 86. The identification result is basically accordant with the gas testing result. It is verified that gas and water layers can be identified effectively based on this logging identification chart

Simultaneous Enhancement of Thermoelectric Power Factor and Phase Stability of Tin-Based Perovskites by Organic Cation Doping

Tin-based halide perovskites are promising room-temperature thermoelectric materials due to their ultralow thermal conductivity and propensity for doping. However, poor phase stability and inferior electrical transport properties hinder their practical application. Herein, we found that organic cation formamidinium (FA) doping, which is not possible by high-temperature processing, could simultaneously enhance the stability and electrical conductivity of CsSnI3 films through a simple solution process. The carrier concentration of 3 × 1019 cm–3 was obtained in FA-doped films, which leads to an 8× enhancement in electrical conductivity to 26.5 S cm–1 but maintains a Seebeck coefficient as high as 131 μV K–1, resulting in a power factor of 45.53 μW m–1 K–2. A further theoretical calculation shows that the enhanced carrier concentration originates from the lowered transition energy of tin vacancies in the doped films. More importantly, remarkable phase stability is achieved under an ambient atmosphere, which stems from a sharply decreased free energy of the B-γ phase compared to the Y phase by FA doping. This work suggests that organic cation doping by facile solution processing is an avenue for the simultaneous improvement of the thermoelectric power factor and phase stability of tin-based halide perovskite. It is applicable for flexible and wearable thermoelectric generators to harvest energy from low-grade heat sources.</p