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The H atom tunneling dissociation dynamics of the S1 state of meta- or para-cresol has been investigated by using the picosecond time-resolved pump-probe spectroscopy in a state-specific manner. The S1 state lifetime (mainly due to the H atom tunneling reaction) is found to be mode-dependent whereas it quickly converges and remains constant as the rapid intramolecular vibrational energy redistribution (IVR) starts to participate in the S1 state relaxation with the increase of the S1 internal energy (Eint). The IVR rate and its change with increasing Eint have been reflected in the parent ion transients taken by tuning the total energy (hνpump + hνprobe) just above the adiabatic ionization threshold (so that the dissipation of the initial mode-character could be monitored as a function of the reaction time), indicating that the mode randomization rate into the S1 isoenergetic manifolds exceeds the tunneling rate quite early in terms of Eint for m-cresol (≤∼1200 cm−1) or p-cresol (≤∼800 cm−1) compared to the case of phenol (≤∼1800 cm−1). Though the H atom tunneling dynamics of phenol (S1) seems to be little influenced by the methyl substitution on the either m- or p-position, the IVR rate has been found to be strongly accelerated due to the sharply-increasing (S1) density of states with increasing Eint due to the pivotal role of the low-frequency CH3 torsional mode. [ABSTRACT FROM AUTHOR]

In this paper, a three-phase single-stage AC-DC converter for an IPT-based small wind power generation system (WPGS) with an S-S compensation circuit is proposed. It applies a three-phase single-stage AC-DC converter to improve the input power factor (PF), efficiency, and reliability in small WPGSs. Also, inductive power transfer (IPT) was applied to compensate for brush wear in the nacelle of small and medium-sized wind turbines while ensuring electrical safety. In conditions of the three-phase Permanent Magnet Synchronous Generator (PMSG) voltage (80~260 Vrms) for the wind turbine and the load (150~1000 W), it was verified that the desired output voltage below 3% can be controlled through the fixed link voltage (VLink) control without wireless communication. A 1 kW prototype was built and tested to demonstrate its applicability to the rotation of small and medium-sized wind turbine nacelles instead of brushes and slip rings. [ABSTRACT FROM AUTHOR]

Mode-dependent H atom tunneling dynamics of the O–H bond predissociation of the S1 phenol has been theoretically analyzed. As the tunneling is governed by the complicated multi-dimensional potential energy surfaces that are dynamically shaped by the upper-lying S1(ππ*)/S2(πσ*) conical intersection, the mode-specific tunneling dynamics of phenol (S1) has been quite formidable to be understood. Herein, we have examined the topography of the potential energy surface along the particular S1 vibrational mode of interest at the nuclear configurations of the S1 minimum and S1/S2 conical intersection. The effective adiabatic tunneling barrier experienced by the reactive flux at the particular S1 vibrational mode excitation is then uniquely determined by the topographic shape of the potential energy surface extended along the conical intersection seam coordinate associated with the particular vibrational mode. The resultant multi-dimensional coupling of the specific vibrational mode to the tunneling coordinate is then reflected in the mode-dependent tunneling rate as well as nonadiabatic transition probability. Remarkably, the mode-specific experimental result of the S1 phenol tunneling reaction [K. C. Woo and S. K. Kim, J. Phys. Chem. A 123, 1529–1537 (2019)] (in terms of the qualitative and relative mode-dependent dynamic behavior) could be well rationalized by semi-classical calculations based on the mode-specific topography of the effective tunneling barrier, providing the clear conceptual insight that the skewed potential energy surfaces along the conical intersection seam (strongly or weakly coupled to the tunneling reaction coordinate) may dictate the tunneling dynamics in the proximity of the conical intersection. [ABSTRACT FROM AUTHOR]

Developing coherent excitation methods for quantum emitters ensuring high brightness, optimal single‐photon purity and indistinguishability of the emitted photons has been a key challenge in the past years. While various methods have been proposed and explored, they all have specific advantages and disadvantages. This study investigates the dynamics of the recent swing‐up scheme as an excitation method for a two‐level system and its performance in single‐photon generation. By applying two far red‐detuned laser pulses, the two‐level system can be prepared in the excited state with near‐unity fidelity. The successful operation and coherent character of this technique are demonstrated using a semiconductor quantum dot (QD). Moreover, the multi‐dimensional parameter space of the two laser pulses is explored to analyze its impact on excitation fidelity. Finally, the performance of the scheme as an excitation method for generating high‐quality single photons is analyzed. The swing‐up scheme itself proves effective, exhibiting nearly perfect single‐photon purity, while the observed indistinguishability in the studied sample is limited by the influence of the inevitable high excitation powers on the semiconductor environment of the quantum dot. [ABSTRACT FROM AUTHOR]

Ultrafast charge carrier dynamics of green‐light emitting InP/ZnSe/ZnS core–shell quantum dots (QDs) with three different ZnSe thickness of 2.0 nm (gQD‐20), 2.4 nm (gQD‐24), or 3.3 nm (gQD‐33) are interrogated by femtosecond transient absorption (TA) and femtosecond stimulated Raman spectroscopy (FSRS). Auger‐type cooling of hot electron into the band‐edge level of InP is clearly manifested in the TA spectra, giving its time constant of ≈222, 300, or 349 fs for gQD‐20, gQD‐24, or gQD‐33, respectively, indicating that the state‐filling to the 1S(e) of InP is significantly slowed down with the increase of the mid shell thickness. The global analysis of the whole TA spectra turns out to be extremely useful to explain the dynamic behavior of the heterogeneous ensemble of single and/or bi‐ (or multi‐) excitons in the presence of the Stark‐shift. The hole‐relaxation dynamics into the band‐edge 1S (h) of the core InP is revealed in the bleaching dynamics of the FSR bands corresponding to the phonon mode of InP or ZnSe, giving the estimated lifetime of 1.0–1.4 ps for gQD‐20. The hole‐relaxation dynamics by the phonon emission seem to be little sensitive to the ZnSe shell thickness. [ABSTRACT FROM AUTHOR]

Photofragmentation dynamics of cis and trans isomers of 1,2-dibromoethylene (1,2-DBE) have been investigated by multiphoton excitation using a picosecond (ps) laser pulse. It has been found that the Br2+ product ion preferentially originates from the cis isomer rather than from trans. The Boltzmann-type isotropic low kinetic energy components of the Br+ and Br2+ product state distributions seem to be most likely from the unimolecular reactions of the vibrationally hot cationic ground state generated by the three-photon absorption at the photon energy below ∼38 000 cm−1. The highly anisotropic kinetic energy components of Br+ and Br2+ start to appear at the photon energy above ∼38 000 cm−1, where the Dn (n ≥ 1) − D0 transition is facilitated within the same ps laser pulse as the parent molecule is efficiently ionized by the two-photon absorption. The transition dipole moment of the D4 − D0 transition of the strongest oscillator strength has been theoretically predicted to be parallel to the C–Br bond or C=C bond axis for the trans or cis isomer, respectively. The fast anisotropic with the (β ∼ +2) component in the Br+ product distribution is thus likely from the trans isomer, whereas that of Br2+ (β ∼ −0.5) should be the consequence of the photodissociation of the cis isomer. The isomer-specific reactivity found here in the picosecond multiphoton excitation of 1,2-DBE provides a nice platform for the better understanding of the structure–reactivity relationship under the harsh condition of the strong or ultrashort optical field. [ABSTRACT FROM AUTHOR]

Vibronic spectroscopy and the S–H bond predissociation dynamics of 2-methoxythiophenol (2-MTP) in the S1 (ππ*) state have been investigated for the first time. Resonant two-photon ionization and slow-electron velocity map imaging (SEVI) spectroscopies have revealed that the S1–S0 transition of 2-MTP is accompanied with the planar to the pseudoplanar structural change along the out-of-plane ring distortion and the tilt of the methoxy moiety. The S1 vibronic bands up to their internal energy of ∼1000 cm−1 are assigned from the SEVI spectra taken via various S1 vibronic intermediate states with the aid of ab initio calculations. Intriguingly, Fermi resonances have been identified for some vibronic bands. The S–H bond breakage of 2-MTP occurs via tunneling through an adiabatic barrier under the S1/S2 conical intersection seam, and it is followed by the bifurcation into either the adiabatic or nonadiabatic channel at the S0/S2 conical intersection where the diabatic S2 state (πσ*) is unbound with respect to the S–H bond elongation coordinate, giving the excited (Ã) or ground ( X ̃ ) state of the 2-methoxythiophenoxy radical, respectively. Surprisingly, the nonadiabatic transition probability at the S0/S2 conical intersection, estimated from the velocity map ion images of the nascent D fragment from 2-MTP-d1 (2-CH3O–C6H4SD) at the S1 zero-point energy level, is found to be exceptionally high to give the X ̃ /Ã product branching ratio of 2.03 ± 0.20, which is much higher than the value of ∼0.8 estimated for the bare thiophenol at the S1 origin. It even increases to 2.33 ± 0.17 at the ν452 mode (101 cm−1) before it rapidly decays to 0.69 ± 0.05 at the S1 internal energy of about 2200 cm−1. This suggests that the strong intramolecular hydrogen bonding of S⋯D⋯OCH3 in 2-MTP at least in the low S1 internal energy region should play a significant role in localizing the reactive flux onto the conical intersection seam. The minimum energy pathway calculations (second-order coupled-cluster resolution of the identity or time-dependent-density functional theory) of the adiabatic S1 state suggest that the intimate dynamic interplay between the S–H bond cleavage and intramolecular hydrogen bonding could be crucial in the nonadiabatic surface hopping dynamics taking place at the conical intersection. [ABSTRACT FROM AUTHOR]

In this study, we determined the probiotic properties and safety of Limosilactobacillus reuteri KGC1901 isolated from Korean Panax ginseng root. This strain was identified based on its 16s rRNA sequence, and the absence of genes related to antibiotic resistance and virulence was confirmed through whole genome analysis in terms of safety. Moreover, this strain had no antibiotic resistance to eight antibiotics as proposed by the European Food Safety Authority, did not show hemolytic activity on blood agar, and did not produce biogenic amines. L. reuteri KGC1901 also showed the capability to survive at low pH and in presence of bile salts and sufficiently adhered to HT-29 cells and mucin. The adhesion ability to HT-29 was confirmed by immunofluorescence staining. These results indicated the excellent viability of L. reuteri KGC1901 in the human gastrointestinal tract. Additionally, L. reuteri KGC1901 had antimicrobial activity against Clostridium difficile, and the presence of the reuterin (3-HPA) biosynthetic gene cluster in the genome was revealed. Furthermore, the cell-free supernatant of KGC1901 had DPPH scavenging activity and reduced the nitric oxide production in LPS-stimulated RAW 264.7 cells. Based on these results, it was confirmed that L. reuteri KGC1901 derived from ginseng has sufficient potential to be used as a probiotic. [ABSTRACT FROM AUTHOR]

Summary: Maintaining the viability of probiotics is critical for maximising their functionality. In this study, tara gum, basic amino acids, rice protein and red ginseng dietary fibre were sequentially applied to encapsulate various probiotic strains to improve their viability and enhance their adhesion to intestinal cells. Compared with uncoated control strains, multilayer‐coated probiotic strains exhibited higher survival rates under low pH conditions (maximum survival: 81.8% for Lactobacillus casei) and bile acid conditions (>50% survival for Lactobacillus rhamnosus). Multicoating also increased the ability of probiotic strains to adhere to intestinal epithelial cells. For example, encapsulated L. reuteri exhibited 56.9% adhesion, which was approximately four‐fold higher than that of the uncoated strain. Moreover, compared with the uncoated strains, multicoated strains exhibited significantly improved storage stability under various temperatures after freeze‐drying. Therefore, the quadruple‐coating technology used in this study enhances the viability and stability of probiotic strains, which is a key advantage from the industrial perspective. [ABSTRACT FROM AUTHOR]

We propose a decision-making framework on infrastructure policy conflict management based on a scientific approach. We developed a decision-making framework that consists of the systematic conflict structure diagnosis, decision-making accordingly, and feedback to be used consistently in the policy life cycle and applied it to new airport projects in South Korea. We suggested a model structure of conflict factors leading to the generation of conflict situations and damages in the process and developed the conflict level diagnosis table and the conflict level matrix formed of the possibility of conflict generation and the severity based on the table. We then implemented a decision-making framework that includes decision-making based on it. The case analysis results confirmed the need for a structural diagnosis of conflict and decision-making based on the framework. The developed framework is expected to have scalability for science progress on infrastructure policy conflict management. [ABSTRACT FROM AUTHOR]

We investigated the potential probiotic properties of Limosilactobacillus fermentum KGC1601 isolated from Panax ginseng. Ginseng cultivated in an experimental field of the Korea Ginseng Research Institute was fermented, followed by single colony selection from MRS agar. We performed 16s-rRNA sequencing and whole-genome analysis to identify L. fermentum and evaluate the biosafety parameters of this strain, respectively. We confirmed this strain was susceptible to six antibiotics, as proposed by the European Food Safety Authority, did not produce biogenic amines, and did not exhibit any hemolytic activity. Acid resistance and bile salt tolerance, which are essential properties of a probiotic agent, were investigated. Notably, distinguishing properties of this strain were that it exhibited excellent bile salt tolerance and anti-inflammatory effects. The excellent bile salt tolerance was confirmed by scanning electron microscopy. Through qRT-PCR and ELISA studies, it was revealed that L. fermentum KGC1601 pre-treatment up-regulates anti-inflammatory cytokines and down-regulates pro-inflammatory cytokines in RAW 264.7 cells. Consequently, we suggested that L. fermentum KGC1601 can be safely used as a potential anti-inflammatory functional probiotic agent. [ABSTRACT FROM AUTHOR]

Non-adiabatic couplings between Born–Oppenheimer (BO)-derived potential energy surfaces are now recognized as pivotal in describing the non-radiative decay of electronically excited molecules following photon absorption. This opinion piece illustrates how non-BO effects provide photostability to many biomolecules when exposed to ultraviolet radiation, yet in many other cases are key to facilitating 'reactive' outcomes like isomerization and bond fission. The examples are presented in order of decreasing molecular complexity, spanning studies of organic sunscreen molecules in solution, through two families of heteroatom containing aromatic molecules and culminating with studies of isolated gas phase H2O molecules that afford some of the most detailed insights yet available into the cascade of non-adiabatic couplings that enable the evolution from photoexcited molecule to eventual products. This article is part of the theme issue 'Chemistry without the Born–Oppenheimer approximation'. [ABSTRACT FROM AUTHOR]

A new adaptive ${h}$ -refinement strategy is investigated for a perfect electric conducting rectangular target using the electric field integral equation. The strategy excludes cells below a specified size from the ${h}$ -refinement process when their errors have not improved despite previous refinement. By doing this, the algorithm prevents edge cells from being divided repeatedly at the detriment of other regions of the domain. The performance of several ${h}$ -refinement strategies using discontinuity error estimators is compared. The proposed strategy is shown to offer an improved accuracy/efficiency trade-off in the computed radar cross section. [ABSTRACT FROM AUTHOR]

The πσ*‐mediated photochemistry of heteroaromatic molecules has provoked the investigation of the conical intersection dynamics. The Born–Oppenheimer approximation fails at the conical intersection where the S1 (ππ*) and S2 (πσ*) states cross. The nonadiabatic transitions are much influenced by the nuclear configuration of the reactive flux particularly in the curve‐crossing region encountered along the reaction pathway. In this article, we focus on the tunneling dynamics of phenols and thiophenols. The O (S)H bond cleavage occurs via tunneling through the barrier which is dynamically shaped by the upper‐lying S1/S2 conical intersection in terms of the couplings at the individual branching planes as well as along the (3N‐8) dimensional seam coordinates. State‐specific tunneling rates and their interpretation are given for phenol, substituted phenols, thiophenol, ortho‐substituted thiophenols, and benzenediols including their 1:1 water clusters. The completely orthogonal modes to the tunneling coordinate are very critical in the dynamic shaping of the reaction barrier. [ABSTRACT FROM AUTHOR]

Infinitely thin multiple strip scattering problems are studied using the subdomain approach for two-dimensional (2-D) transverse magnetic and transverse electric excitations. The subdomain approach divides the entire domain into several partially overlapping subdomains, within which fields are expanded by classical techniques. The mode-matching method is used to impose continuity conditions. Results are validated by comparing to numerical results from COMSOL. Results show that the subdomain approach can be as accurate as the numerical solutions and may offer substantial improvements in efficiency. [ABSTRACT FROM AUTHOR]

Research into the photodissociation dynamics of hexafluoroacetylacetone is presented. The impact of the H/F substitution of two methyl groups of acetylacetone on the intramolecular hydrogen-bond strength and the chemical bond dissociation dynamics is discussed.

We propose a decision-making framework on infrastructure policy conflict management based on a scientific approach. We developed a decision-making framework that consists of the systematic conflict structure diagnosis, decision-making accordingly, and feedback to be used consistently in the policy life cycle and applied it to new airport projects in South Korea. We suggested a model structure of conflict factors leading to the generation of conflict situations and damages in the process and developed the conflict level diagnosis table and the conflict level matrix formed of the possibility of conflict generation and the severity based on the table. We then implemented a decision-making framework that includes decision-making based on it. The case analysis results confirmed the need for a structural diagnosis of conflict and decision-making based on the framework. The developed framework is expected to have scalability for science progress on infrastructure policy conflict management. [ABSTRACT FROM AUTHOR]

Perfect electric conducting (PEC) sectors illuminated by transverse magnetic (TM) and transverse electric (TE) field excitations are studied using the subdomain approach. The subdomain approach, which is similar to the method of overlapping regions (MOR) and the T-block method, requires field expansions in overlapping subdomains and subsequent mode matching. Results for surface current densities are compared with numerical results from COMSOL for problems involving wave scattering from PEC sectors of finite dimension. Results show that the subdomain approach can be as accurate as other numerical solutions and maybe more computationally efficient. [ABSTRACT FROM AUTHOR]