All-optical spatio-temporal control of electron emission from SiO2 nanospheres with femtosecond two-color laser fields

Field localization by nanostructures illuminated with laser pulses of well-defined waveform enables spatio-temporal tailoring of the near-fields for sub-cycle control of electron dynamics at the nanoscale. Here, we apply intense linearly-polarized two-color laser pulses for all-optical control of the highest energy electron emission from SiO2 nanoparticles. For the size regime where light propagation effects become important, we demonstrate the possibility to control the preferential emission angle of a considerable fraction of the fastest electrons by varying the relative phase of the two-color field. Trajectory based semi-classical simulations show that for the investigated nanoparticle size range the directional steering can be attributed to the two-color effect on the electron trajectories, while the accompanied modification of the spatial distribution of the ionization rate on the nanoparticle surface has only a minor effect. © 2019 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaf

All-optical spatio-temporal control of electron emission from SiO2 nanospheres with femtosecond two-color laser fields

Field localization by nanostructures illuminated with laser pulses of well-defined waveform enables spatio-temporal tailoring of the near-fields for sub-cycle control of electron dynamics at the nanoscale. Here, we apply intense linearly-polarized two-color laser pulses for all-optical control of the highest energy electron emission from SiO2 nanoparticles. For the size regime where light propagation effects become important, we demonstrate the possibility to control the preferential emission angle of a considerable fraction of the fastest electrons by varying the relative phase of the two-color field. Trajectory based semi-classical simulations show that for the investigated nanoparticle size range the directional steering can be attributed to the two-color effect on the electron trajectories, while the accompanied modification of the spatial distribution of the ionization rate on the nanoparticle surface has only a minor effect.11Ysciescopu

Using Import Data to Predict the Potential of Introduction of Alert Alien Species to South Korea

As globalization progresses, human activities, such as travel and trade, are rapidly increasing beyond national boundaries. It is increasingly recognized that places, such as ports and airports, where trade occurs play a major role as an introduction pathway for alien species. In this study, we focused on evaluating the possibility of introduction of Alert Alien Species (AAS) through trade data among countries. The natural and distribution range of AAS were analyzed along with import data by country. There were large differences between the number of AAS distributed in a country and the import weight of items related to the import of AAS from the country. Fish, which account for 76% of the import weight of AAS, 43 and 40 species of the 84 species of AAS were distributed in US and Russia, respectively. However, the import weight of items related to the import of fish designated as AAS from these countries were extremely low. This finding suggests that trade, which is the main introduction pathway, is not taken into account in the designation of AAS. For future management plans for non-introduced alien species, species with a high possibility of introduction into South Korea through trade should be prioritized using import data

Using Import Data to Predict the Potential of Introduction of Alert Alien Species to South Korea

As globalization progresses, human activities, such as travel and trade, are rapidly increasing beyond national boundaries. It is increasingly recognized that places, such as ports and airports, where trade occurs play a major role as an introduction pathway for alien species. In this study, we focused on evaluating the possibility of introduction of Alert Alien Species (AAS) through trade data among countries. The natural and distribution range of AAS were analyzed along with import data by country. There were large differences between the number of AAS distributed in a country and the import weight of items related to the import of AAS from the country. Fish, which account for 76% of the import weight of AAS, 43 and 40 species of the 84 species of AAS were distributed in US and Russia, respectively. However, the import weight of items related to the import of fish designated as AAS from these countries were extremely low. This finding suggests that trade, which is the main introduction pathway, is not taken into account in the designation of AAS. For future management plans for non-introduced alien species, species with a high possibility of introduction into South Korea through trade should be prioritized using import data

An Empirical Investigation of Personalized Recommendation and Reward Effect on Customer Behavior: A Stimulus–Organism–Response (SOR) Model Perspective

With the continuous growth in the Home Meal Replacement (HMR) market, the significance of recommender systems has been raised for effectively recommending customized HMR products to each customer. The extant literature has mainly focused on enhancing the performance of recommender systems based on offline evaluations of customers’ past purchase records. However, since the existing offline evaluation methods evaluate the consistency of products on the recommendation list with ones purchased by customers from the test dataset, they are incapable of encompassing components such as serendipity and novelty that are also crucial in recommendation. Moreover, the existing offline evaluation methods cannot measure rewards such as discount coupons that may play a vital role in strengthening customers’ desire for purchase and thereby stimulating their purchase with a provision of a recommendation list. In this study, we used an SOR model to verify the effect of personalized recommendation stimulus on a customer’s response in an actual online environment. The results indicate that the customers’ response rate was higher with a provision of personalized recommendations than that of bestseller recommendations, and higher when being offered with cash discounts than earning redeemable points. Meanwhile, the response rate to the recommendation with higher volumes of rewards was not as high as expected, while the point pressure mechanism did not work either

Efficient semi-transparent perovskite quantum dot photovoltaics enabled by asymmetric dielectric/metal/dielectric transparent electrodes

CsPbI3 perovskite quantum dots (CsPbI3-PQDs) have a high potential as semi-transparent photovoltaic absorbers because of the facile control of film thicknesses, size-tunable optical band gaps, and nanometer-scale grain sizes suppressing light scattering. Conventional semi-transparent CsPbI3-PQD solar cells showed low photovoltaic performances due to the low electrical conductivity of the graphene electrodes. Here we report that dielectric/ultra-thin metal/dielectric (DMD) electrodes with excellent optical transmittance and electrical conductivity deliver superior photovoltaic performances in the semi-transparent CsPbI3-PQD solar cells. Particularly, the asymmetric DMD electrodes composed of MoOx 15 nm/Au 10 nm/MoOx 35 nm (asym-MAM) stacks exhibit higher optical transmittance than that of the symmetric MoOx 15 nm/Au 10 nm/MoOx 15 nm (sym-MAM) stacks. The optical simulation confirms that asym-MAM stacks reduce the parasitic absorption loss in metal interlayers. Therefore, the asym-MAM stacks with a high electrical conductivity show a higher average visible transmittance (AVT) than that of the sym-MAM. Consequently, the semi-transparent CsPbI3-PQD solar cells fabricated using the asym-MAM transparent top electrodes show a power conversion efficiency of 11.3% with a considerable AVT values of 23.4% (400–800 nm) and 20.0% (380–780 nm), respectively, which were calculated from their transmittance spectra. This is the highest-efficiency semi-transparent PQD solar cells that can be used for solar window applications requiring an AVT value of over 20%. © 2023 Elsevier B.V.FALS

The current status of invasive alien insect species in South Korea

We investigated the identity and distribution of the invasive alien insect species inhabiting Korean ecosystems, targeting 3,249 locations in nine regions between 2015 and 2018. In natural ecosystems, we identified 63 species in 43 families and nine orders of invasive alien insect species, respectively. We observed that the order Hemiptera exhibited the highest species diversity with 20 species. Gyeonggi-do was where the highest number of invasive alien insect species were identified (45 species). Species richness analysis revealed that Jeju-do showed the highest Dominance Index (0.8), whereas Gyeongsangnam-do had the highest Diversity Index (2.8). Corythucha marmorata (Hemiptera: Tingidae), Lycorma delicatula (Hemiptera: Fulgoridae), Ophraella communa (Coleoptera: Chrysomeridae), Metcalfa pruinosa (Say) (Hemiptera: Flatidae) and Pochazia shantungensis (Hemiptera: Ricaniidae) were distributed in more than 300 locations of the country. Invasive alien insect species inhabited the roadsides (31.3%), farmlands (18.3%) and parks (16.6%). In this study, we list the invasive alien insect species in Korean ecosystems and provide a basis for selecting primary management target species

High-contrast, intense single-cycle pulses from an all thin-solid-plate setup

High-contrast, intense single-cycle pulses are highly desirable tools in ultrafast science, enabling highest temporal resolution, pushing matter to extreme conditions, and serving as drivers in petahertz electronics. In this Letter, we use thin solid plates in a double multi-plate supercontinuum configuration, delivering a broadband spectrum spanning from similar to 400 to similar to 4.000 nm at the -20 dB intensity level to produce a single-cycle pulse. We show that the spectral broadening by self-phase modulation with few-cycle pulses is more suitable for compression than the single-cycle limit than with multi-cycle pulses. The pulses are compressed to 2.6 fs pulses, close to the transform limit of 2.55 fs, with an energy of 0.235 mJ. They exhibit an excellent power stability of 0.5% rms over 3 h and a beam profile. The obtained single-cycle pulses can be utilized in many applications, such as generation of isolated attosecond pulses via high-order harmonic generation, investigation of ultrafast phenomena with extreme temporal resolution, or high-intensity laser-solid experiments. (C) 2020 Optical Society of America11Nsciescopu

Ant occurrence dataset regarding Linepithema humile (Mayr, 1868) (Hymenoptera, Formicidae), first recorded in Busan, South Korea

This study contains information regarding the occurrence of ants in the area near Busan station, where the invasion of Linepithema humile was reported for the first time in South Korea. The Argentine ant is '100 of World’s Worst invasive Alien Species', commonly discovered in disturbed places, and its spread to other areas causes local ecosystem disturbances. Therefore, we investigated the associated fauna in the invaded areas to determine the L. humile invasion effects on the native ants in Busan, Korea.This study is based on a field study conducted over four days, from July 12 to July 15, 2022. The location information of the 3,383 individuals, consisting of 14 species of Formicidae in the L. humile-invaded area is also provided. All data in the study site, excluding those regarding L. humile, were reported for the first time