Soliton dual comb in crystalline microresonators

We present a novel compact dual-comb source based on a monolithic optical crystalline MgF$_2$ multi-resonator stack. The coherent soliton combs generated in two microresonators of the stack with the repetition rate of 12.1 GHz and difference of 1.62 MHz provided after heterodyning a 300 MHz wide radio-frequency comb. Analogous system can be used for dual-comb spectroscopy, coherent LIDAR applications and massively parallel optical communications.Comment: 5 pages, 5 figure

EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 08, Revision 5 (FGE.08Rev5): Aliphatic and alicyclic mono-, di-, tri-, and polysulphides with or without additional oxygenated functional groups from chemical groups 20 and 30

<p>The CEF Panel of the European Food Safety Authority was requested to evaluate 80 flavouring substances in the Flavouring Group Evaluation 08, Revision 4, using the Procedure in Commission Regulation (EC) No 1565/2000. Since the publication of the last revision of this FGE, the EFSA has been requested to evaluate additional toxicological data submitted for two flavouring substances, one substance 2,5-dihydroxy-2,5-dimethyl-1,4-dithiane [FL-no: 15.006], which support the evaluation of the candidate substance 2,5-dihydroxy-1,4-dithiane [FL-no: 15.134] and one on the candidate substance spiro(2,4-dithia-1-methyl-8-oxabicyclo[3.3.0]octane-3,3’-(1’-oxa-2’-methyl)-cyclopentane) and spiro(2,4-dithia-6-methyl-7-oxabicyclo[3.3.0]octane-3,3’-(1’-oxa-2’-methyl)-cyclopentane) [FL-no: 15.007], which have been included in the present revision of FGE.08. For the substances methyl methanethiosulphonate [FL-no: 12.159], 2-methylbutane-2-thiol [FL-no: 12.172], 2-methylpropane-2-thiol [FL-no: 12.174], ethyl-2-mercapto-2-methyl propanoate [FL-no: 12.304] and 2,4,4-trimethyl-1,3-oxathiane [FL-no: 16.057] there is an indication of a genotoxic potential in vitro. Therefore, without further genotoxicity data, the Panel concluded that the Procedure could not be applied to these five substances. For four substances, 3-mercaptooctanal [FL-no: 12.268], 3-mercaptodecanal [FL-no: 12.269], methanedithiol diacetate [FL-no: 12.271] and 3,5-dimethyl-1,2-dithiolane-4-one [FL-no: 12.295] no data on use as flavouring substances in Europe are available and no intake figures could be calculated, which preclude the evaluation of the four substances using the Procedure. The remaining 71 substances were evaluated through a stepwise approach that integrates information on the structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel concluded that 59 substances do not rise safety concerns at their levels of dietary intake, estimated on the basis of the MSDI approach. For 12 substances [FL-no: 12.093, 12.094, 12.097, 12.100, 12.112, 12.116, 12.120, 12.164, 12.167, 12.199, 15.102 and 15.125], evaluated through the Procedure, no appropriate NOAEL was available and additional data are required. The specifications for the materials of commerce have also been considered and for three substances, information on the specifications is lacking.</p&gt

Aggregation and Conductivity in Hot-Grown Petroporphyrin Films

As a follow-up to our study on aggregation of metal-etioporphyrin complexes (Colloids Surf. A. Physicochem. Eng. Asp. 2022, 648, 129284), we considered thin films of three isomers of copper(II) etioporphyrin deposited on hot substrates. Despite the almost identical absorption spectra of isomers, their solid-state superstructures differ remarkably both in form and size. The lateral conductivity of films is much less sensitive to an isomer-type, regardless of the substrate temperature. However, the dark conductivity of cold-grown films is about two orders of magnitude higher than that of hot-grown films, whereas the photoconductivity of the latter is 100–1700 times greater, depending on the isomer

ELECTROHYDROCYLINDER OF INCREASED EFFICIENCY: PROSPECTS FOR THE DEVELOPMENT OF MECHATRONIC SYSTEMS

Introduction. The problem of increasing the efficiency of power machines is important to develop a new design of the main elements or drive with the possibility of widespread use of hybrid drives. To preserve the power characteristics of the drive and its technical and operational indicators, the authors consider a hybrid with the available electric and hydraulic drive parts that form a complex synergistic mechanism as an alternative. The proposed combined tracking system with the specified parameters allows for the efficient operation of the drive of many machines.Materials and methods. The paper presented the results of an analytical study, the prospects for the development of mechatronic systems in engineering and technological complexes. The research also identified the industry area with a high development potential for mechatronic and hybrid drives. The authors formulated the problem of designing and developing hybrid drives due to the fact that there was no single method for substantiating the energy efficiency indicators of a power hybrid drive that ensured the interaction of two dissimilar systems (electric drive and hydraulic drive with fundamentally different parameters).Results. Therefore, the authors conducted the analysis of the structural, technological and operational parameters of the hybrid drive systems and proposed a combined servo drive system.Discussion and conclusions. The authors prove and justify the extensive possibilities of using hybrid drives as an alternative to pneumatic and hydraulic drives The results of the research allow specifying the directions and prospects of using hybrid synergetic drives and systems for the functioning of working equipment, machines and complexes.Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest

Iron(II) Complexes with Porphyrin and Tetrabenzoporphyrin: CASSCF/MCQDPT2 Study of the Electronic Structures and UV–Vis Spectra by sTD-DFT

The geometry and electronic structures of iron(II) complexes with porphyrin (FeP) and tetrabenzoporphyrin (FeTBP) in ground and low-lying excited electronic states are determined by DFT (PBE0/def2-TZVP) calculations and the complete active space self-consistent field (CASSCF) method, followed by the multiconfigurational quasi-degenerate second-order perturbation theory (MCQDPT2) approach to determine the dynamic electron correlation. The minima on the potential energy surfaces (PESs) of the ground (3A2g) and low-lying, high-spin (5A1g) electronic states correspond to the planar structures of FeP and FeTBP with D4h symmetry. According to the results of the MCQDPT2 calculations, the wave functions of the 3A2g and 5A1g electronic states are single determinant. The electronic absorption (UV–Vis) spectra of FeP and FeTBP are simulated within the framework of the simplified time-dependent density functional theory (sTDDFT) approach with the use of the long-range corrected CAM-B3LYP function. The most intensive bands of the UV–Vis spectra of FeP and FeTBP occur in the Soret near-UV region of 370–390 nm

Applications of Focused X-Ray Laser at 21 nm in High-Energy Density Experiments

We report on the generation of a focused X-ray laser beam with high energy density. The output of the 21.2 nm X-ray laser at PALS containing energy of 4 mJ was focused down to 20 x 40 μm2 elliptical spot. Samples of various solids were irradiated by the focused X-ray laser beam at various fluences. Feasibility of single-shot projection ablation lithography has been explored. First measurement of the XUV opacity of volumetrically heated thin foil by the focused X-ray laser has been performed