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In spring 2011, two field trials on site-specific weed control in winter wheat and maize were carried out at Ihinger Hof research station of the University of Hohenheim. For the image acquisition, bi-spectral cameras were mounted on a vehicle. These cameras are able to take images free from disturbances by soil, mulch and stones. Images and the corresponding GPS-data were stored on-the-go. Afterwards, the images were analyzed by a weed recognition software. Weed infestation was mapped in consideration of weed species and weeds grouped according to their herbicide sensitivity. In order to simulate an online herbicide application, a onesided moving average of order five was used for the weed mapping. This kind of rearward calculation uses only the data of weed infestation which were already assessed behind or directly in the current position of the vehicle. The calculated weed distribution maps were checked by visual grid sampling. Herbicide application maps were generated by applying weed thresholds on the weed distribution maps. The herbicide application based on the maps was conducted by a multiple sprayer which allows the application of up to three herbicides independently from each other in a single pass across the field. Later on, the performance of the herbicide application was controlled again by visual grid sampling. Compared to a uniform herbicide application, the sitespecific weed control saved 83 % and 58 % herbicides respectively in winter wheat and 66 % in maize. The average efficacy of the site-specific herbicide application system in winter wheat was 70 % of the conventional herbicide application.

Organic field-effect transistors (OFETs) require ultra-precise electrical measurements due to their unique charge transport mechanisms and sensitivity to environmental factors, yet commercial semiconductor parameter analysers capable of such measurements are prohibitively expensive for many research laboratories. This study introduces a novel, cost-effective, and portable setup for high-precision OFET characterisation that addresses this critical need, providing a feasible substitute for conventional analysers costing tens of thousands of dollars. The suggested system incorporates measurement, data processing, and graphical visualisation capabilities, together with Bluetooth connectivity for local operation and Wi-Fi functionality for remote data monitoring. The device consists of a motherboard and specialised cards for low-current measurement, voltage measurement, and voltage generation, providing comprehensive OFET characterisation, including transfer and output characteristics, in accordance with IEEE-1620 standards. The system can measure current from picoamperes to milliamperes, with voltage measurements supported by high input resistance (>100 MΩ) and a voltage generation range of −30 V to +30 V. This versatile and accessible approach greatly improves the opportunities for future OFET research and development. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) are versatile, easy to fabricate, chemically stable, and ecofriendly materials. This work presents the impact of different post-treatments, such as centrifugation and filtration, on the photoluminescence (PL) and particle-size distribution of electrochemically synthesized CDs. Because organic envelope surfactants have been reported to influence PL, bare CDs were compared with CDs modified with amphiphilic and nonamphiphilic surfactants. The CD colloidal solution exhibited stabilization in the case of bare CDs and CDs modified with amphiphilic sodium dodecyl sulphate or non-amphiphilic surfactant sodium citrate, as indicated by the zeta potential. The experimental results also revealed a minor influence of the organic envelope on the absorbance or PL spectrum, whereas filtration of the colloid solution had a significant impact, revealing an effect not previously observed. The change in the absorbance spectrum was attributed to sp3 hybridization due to increased disorder and surface states during the filtration process. Absorbance deconvolution also disclosed two energy substates not mentioned elsewhere. The PL spectra of the filtered CD solutions revealed that the emission peaks shifted according to the incident wavelength, and the centrifuged CDs synthesized with the sodium citrate surfactant lacked PL due to the absence of sp3 states. This study emphasizes the importance of CD post-treatment in CD production rather than the use of surfactants. [ABSTRACT FROM AUTHOR]

Wide-bandgap semiconductors have been envisioned for power electronics applications because of their ability to operate at higher temperatures and higher applied voltages without breakdown. However, the presence of defects may cause device failure, necessitating a comprehensive understanding of material defects. This review provides a fingerprint of known defects in three envisioned semiconductors for power electronics: 4H-SiC, GaN, and β-Ga2O3. Via a detailed discussion of defects—the origins of electrically active charge traps—through their activation energies and capture cross-sections, we provide important insights into defect parameter distributions. This review not only serves as a reference but also offers a strategic roadmap for distinguishing between similar defects. Such knowledge is key for the development of more robust and efficient power electronic devices that can fully exploit the potential of wide-bandgap semiconductors. [ABSTRACT FROM AUTHOR]