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We report on a thermodynamic analysis of oxide vapor phase epitaxy (OVPE) of GaN. We first calculate equilibrium partial pressures of gases for the initial partial pressures of Ga2O, NH3, and H2 as well as the growth temperature. To estimate the growth rate of a GaN crystal, we then define the supersaturation amount determined by the equilibrium and initial partial pressures. In the calculation, the growth rate is significantly influenced by the initial partial pressures of Ga2O and NH3, while it is almost independent of the initial partial pressure of H2 and the growth temperature. Subsequently, we experimentally grow GaN crystals under same conditions as in the thermodynamic analysis. In the range of conditions in this work, the experimental growth rates are nearly consistent with the growth rates predicted by the thermodynamic analysis for all experimental parameters. Thus, the results showed that a high value of the supersaturation amount is advantageous for high-speed growth. Furthermore, we define the supersaturation ratio and investigate the correlation between this parameter and the surface coverage of the polycrystal. The surface coverage of the polycrystal is confirmed to roughly decrease as the value of the supersaturation ratio decreases. Thus, the results showed that a low value of the supersaturation ratio is advantageous for polycrystal-free growth. Finally, we use the thermodynamic analysis to explore the optimal conditions for high-speed and polycrystal-free growth. This revealed that the optimal OVPE growth conditions are both a high partial pressure of Ga2O and a low partial pressure of NH3. [ABSTRACT FROM AUTHOR]

In this article, we present a simulation study of the linear and nonlinear spectroscopy of dense atomic vapors. Motivated by recent experiments, we focus on double quantum spectroscopy, which directly probes dipole–dipole interactions. By explicitly including thermal velocity, we show that temperature has an important impact on the self-broadening mechanisms of the linear and nonlinear spectra. We also provide analytical expressions for the response functions in the short time limit using the two-body approximation, which shows that double quantum spectroscopy for atomic vapors directly probes the transition amplitude of the electronic excitation between two atoms. We also propose an expression for the double quantum spectrum that includes the effect of Doppler broadening, and we discuss the effect of density on the spectrum. We show that when Doppler broadening is negligible compared to self-broadening, the double quantum spectrum scales with the atomic density, while when Doppler broadening dominates, it scales as the square of the density. [ABSTRACT FROM AUTHOR]

When a contaminated liquid evaporates from within a porous material, the impurities or dirt accumulate and deposit within the pore space. This occurs during the cleaning of filters and fouling of textiles, and is related to the 'coffee-ring' problem. To investigate how and where dirt is deposited in the pore space, we present a model for the motion of an evaporation front through a porous material, and the related accumulation, transport, and deposition of dirt, assuming that the liquid remains stationary. For physically relevant parameters, vapour transport out of the porous material is quasi-steady and we derive a single ordinary differential equation describing the motion of the evaporation front in time. Model solutions exhibit spatially non-uniform profiles of the deposited dirt-layer thickness through the porous material. The dirt accumulation and evaporation problems are coupled: deposited dirt hinders vapour transport through the porous material, slowing the evaporation. We identify two scenarios in which the porous material becomes clogged with dirt. Accumulation of suspended dirt at the evaporating interface along with slow dirt diffusion results in the deposited dirt layers clogging the pores at the evaporating interface, halting the drying and trapping liquid in the porous material. Alternatively, slow dirt deposition results in the suspended dirt being pushed far into the porous material by the evaporation, eventually leaving only dirt (with no liquid) in the pore space. We investigate the dynamics of both clogging scenarios, characterising the parameter regimes for which each occurs. Both clogging scenarios must be avoided in practice since they may be detrimental to future filter efficacy or textile breathability. [ABSTRACT FROM AUTHOR]

We study Zeeman Electromagnetically Induced Transparency (EIT) in an effective three-level closed Λ system involving the D 2 transition of 87 Rb . The impact of coupling intensity and detuning, cell temperature, beam diameters, and transit relaxation rate are explored in a controlled manner on EIT width and peak transmission. Narrow EIT features of FWHM ≈ 36 kHz and peak transmission ≈ 92 % are noted. The dispersive characteristics of the 87 Rb atomic medium, affecting the group index and group delay of the probe beam are also examined. The group index of the atomic medium has a nonlinear dependence on the coupling intensity, indicating that an optimization of the latter is required to attain a maximum reduction of the group velocity for slow light. For a probe beam diameter of 1.5 cm, a maximum group delay of 0.228 μ s can be achieved corresponding to a group velocity of v g = c 914 m/s. Our study especially highlights the impact of a detuned coupling beam on the probe transmission and its group delay. An interesting aspect of a negative group delay is noted for a sufficiently detuned coupling beam at low intensity which signifies the conversion from slow light to fast light. [ABSTRACT FROM AUTHOR]

Alternative refrigerants for R410A, which is most commonly used in building cooling and heating, are being requested with a global warming potential of 750 or lower and these regulations will continue to be implemented. At the current stage, several candidates are being discussed, but these will not be the final solution. What is certain is the R410A replacement refrigerant will be proposed in the form of mixed refrigerants. To figure out the thermodynamic properties of the mixed refrigerant, VLE data must be obtained first. In this study, we performed VLE experiments on a representative mixed refrigerant (R32-R125) to verify our newly constructed VLE experiment facility, and compared the results with the REFPROP 10 and the results of other researchers. The experiment was conducted at a temperature of 273.15 K to 313.15 K, and the maximum MAPE for pressure was found to be 0.0178 % and the maximum MAE for composition was found to be 0.0029. In the future, the facility will be used to present VLE test data with new mixed refrigerants as candidate replacement refrigerants for R410A. [ABSTRACT FROM AUTHOR]

Self-propelled Leidenfrost droplets on asymmetrically structured surfaces were investigated to study their movements with temperature. It was observed that the terminal velocity is a function of temperature in the low-temperature regime (L regime) but not in the high-temperature regime (H regime). Droplets were not smooth in the L regime but were smooth in the H regime. Because of wrinkles, the light penetrating through droplets was deflected, resulting in differences in light levels in the L and H regimes. While the droplet accelerated to reach its terminal velocity when α = 50° and α = 65°, tiny droplets were breaking off from the trailing edge and moving opposite to the droplet's moving direction. When α = 80°, as the droplet accelerated, it leaned forward and its leading edge stood higher than its trailing edge. The distinct shape of the droplet is strong evidence to show that the vapor underneath the droplet flows opposite to the droplet's moving direction. [ABSTRACT FROM AUTHOR]

This study investigated the rolling motion effect on the location of critical heat flux (CHF) for subcooled flow boiling within a mini-channel that is heated from one side. The study employed 15° and 25° as rolling amplitudes and 10 and 30 seconds as rolling periods across two different flow rate conditions. The CHF values observed under static conditions and those under rolling motion were subsequently compared. A key finding was that CHF consistently occurred near the highest positions of the rolling platform, where reduced buoyancy force, due to the absence of centrifugal acceleration, combined with only the radial buoyancy component acting in the flow direction, resulted in a slower bubble rise, facilitating easier coalescence of bubbles into a vapor film, leading to CHF. [ABSTRACT FROM AUTHOR]

In many industrial applications as well as in nature, the mass transfer of CO2 at vapor-liquid interfaces in aqueous systems plays an important role. In this work, this process was studied on the atomistic level using non-equilibrium molecular dynamics simulations. In a first step, a molecular model of the system water + CO2 was developed that represents both bulk and interfacial equilibrium properties well. This system is characterized by a very large adsorption and enrichment of CO2 at the vapor-liquid interface. Then, non-equilibrium mass transfer simulations were carried out using a method that was developed recently: CO2 is inserted into the vapor phase of a simulation box which contains a liquid slab. Surprising effects are observed at the interface such as a net repulsion of CO2 particles from the interface and a complex time dependence of the amount of CO2 adsorbed at the interface. [ABSTRACT FROM AUTHOR]

Variable stiffness Carbon/Carbon (C/C) honeycomb can be designed to exhibit varying stiffness based on the structural load gradient, facilitating a high degree of alignment between structural performance and function. The elimination of mass redundancy and achievement of extreme light-weighting confer promising applications in the aerospace sector. However, the universal preparation approach for variable stiffness honeycomb faces challenges related to material mass redundancy and susceptibility to cracking at the bonds. Consequently, addressing the integrated forming issues associated with variable stiffness honeycomb becomes urgent. In this study, firstly, the conventional honeycomb densification method and the CVI domain-limited reactor design approach for integrated forming of variable-stiffness honeycombs are discussed. Subsequently, a multi-physics field coupling model for C/C honeycomb forming is developed, and its accuracy is validated through honeycomb forming experiments. The influence of three key process parameters, gas residence time, temperature, and pressure, on the quality of honeycomb forming were explored. Following the influence laws, the study applies specific process parameters to the three distinct regions of the reactor. Through this meticulously regulated process, the final variable stiffness honeycomb attains a 17.6 % reduction in weight compared to a constant density honeycomb of the same volume. [ABSTRACT FROM AUTHOR]

• Semi-empirical models for suction flow rate, injection flow rate, input power consumption, and discharge temperature are proposed for scroll compressors with vapor injection. • The modeling approach can be consistently applied to fixed-speed and variable-speed compressors. • The models were fit and evaluated using a data set containing four compressors. The prediction accuracy is similar to other proposed models and the model requires relatively low testing effort to fit the empirical parameters. • The models were applied to one compressor for operation with and without vapor injection. The prediction errors for both modes of operation are similar, while only using one set of model parameters. Semi-empirical models for predicting the suction flow rate, injection flow rate, input power consumption, and discharge temperature are proposed for scroll compressors with vapor injection. A data set containing four compressors wherein each compressor was tested over a range of operating conditions is used to evaluate the models. The fitted parameters of the models and the prediction errors of each data set are discussed. The accuracy and generalizability of applying the models to the same compressor with and without vapor injection are also discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] Porous carbon materials are highly desirable for removing benzene due to their low energy for capture and regeneration. Research has demonstrated that narrow microporous volume is crucial for effective adsorption of benzene at ultra-low concentration. Unfortunately, achieving directional increase in the narrow microporous volume in porous carbon remains a challenge. Here, nitrogen-doped hydrothermal carbon was prepared using urea-assisted hydrothermal method, and then porous carbon (PUC800) was prepared by KOH activation. The resulting material had 180 % higher pore volume and 179 % higher surface area compared to non-nitrogen activation methods. Then, using mechanochemical (mechanical compaction and KOH activation) approach to produce PUC800-3T, which had a 30 % increase in pore volume and a 33 % increase in surface area compared to PUC800. PUC800-3T showed benzene adsorption capacity of 4.2 mmol g−1 at 1 Pa and 5.8 mmol g−1 at 5 Pa. Experimental and molecular simulation indicate that the benzene adsorption at 1 and 5 Pa is determined by pore volume of less than 0.8 and 0.9 nm, respectively. Density functional theory calculations provided insight into the C H⋯X (X = N/O) interactions drive benzene adsorption on the carbon framework. This work provides valuable theoretical and experimental support for designing, preparing, and applying adsorbents for trace removal of benzene vapor. [ABSTRACT FROM AUTHOR]

This paper presents a theoretical analysis of the evaporation of individual compounds from an aerosol in vapor-free conditions, demonstrating that the evaporation of mixture components is interconnected via the ratio of their characteristic times. These characteristic times are proportional to the square of the initial particle diameter and inversely proportional to the compound saturation vapor concentration (SVC). A single ordinary differential equation (ODE) can adequately describe the behavior of all mixture components. It is shown that the time needed to evaporate a specific compound fraction is primarily controlled by the compound's characteristic time, with lesser influences from compound abundance in the mixture and the amount of less volatile material. Consequently, the relative abundance of individual compounds has a minor effect on evaporation. Compounds evaporate in the reverse order of their SVC, with the time required to evaporate 50% of their original mass being roughly half of their characteristic time. The reduction in ODEs provides significant computational benefits. Additional simplifications are derived that further accelerate calculations by two orders of magnitude while maintaining accuracy. The theory can guide experimental design for aerosol volatility measurements and demonstrate that a unique volatility basis set (VBS) can be fit to experimental data if the number of observations equals at least the number of volatility bins minus one. However, assumptions regarding parameters used for VBS fitting can result in ambiguity in the derived VBS, making it essential to use the same parameters for modeling evaporation as those used to derive the VBS from experimental data. [ABSTRACT FROM AUTHOR]

ABSTRACT Surface incident solar radiation (Rs) is of great importance in determining the energy balance in the Earth system. In this study, we use century‐long homogenized observations over Japan to constrain five 20th century reanalyses to explore their performance in reproducing Rs variation on different time scales (high‐frequency components [HFCs], for signals with cycles less than 10 years; low‐frequency components [LFCs], for signals with cycles more than 10 years) by ensemble empirical mode decomposition (EEMD) method and to quantify the impact factors on the Rs estimations by the sum of tree (SOT) model. It is found that ERA20C, ERA20CM and CERA20C overestimated Rs by 0.48–1.49 W/m−2, while 20CRv2c and 20CRv3 underestimated Rs by −0.63 and −1.18 W/m−2, respectively for 1931–2010. Poor correlation coefficient (R) was found to be 0.10 for ERA20CM and 0.22 for 20CRv2c. 20CRv2c failed for 1931–1960 but improved considerably for 1961–2010. 20CRv3 uses an upgraded model and assimilates more observations compared with its predecessor 20CRv2c; however, only the original components and HFCs in Rs were improved, with nearly no improvement in the LFCs. In general, CERA20C Rs, with small biases and higher R of 0.73 for original signals, 0.83 for HFCs and LFCs, is superior to other reanalyses. No obvious trend in clear sky Rs demonstrated that reanalysed Rs are insensitive to the aerosol forcings. Therefore, cloud cover and water vapour maybe the main factors influenced reanalysed Rs. Most of time, Rs is more sensitive to cloud cover than vapour pressure for all reanalyses except original signals (with contribution ratio of 0.29 for cloud cover and 0.71 for vapour pressure) and LFCs (with contribution ratio of 0.41 for cloud cover and 0.59 for vapour pressure) in CERA20C, and original signals (with contribution ratio of 0.37 for cloud cover and 0.63 for vapour pressure) in ERA20C. This work pointed out that aerosol related processes such as aerosol forcings or aerosol radiative effect in reanalyses should be improved in the future, which will ultimately improve the interaction between aerosol and cloud in Rs simulations. [ABSTRACT FROM AUTHOR]

Microwave gas monitoring with a low‐profile design and enhanced selectivity remains a persistent challenge. This study introduces an innovative approach employing a real‐time wireless reconfigurable intelligent surface (RIS) for comparative investigation of the interaction of two distinct polydimethylsiloxane (PDMS) interfaces, i.e., solid and porous, with acetone gas molecules. The developed PDMS‐coated microwave RIS detects varying concentrations of acetone vapor by wirelessly monitoring variations in the resonant characteristics of the resonating RIS beneath the sensitive interface. This PDMS‐coated microwave RIS is validated through exposure to incremental (15–75) parts per thousand (ppt) acetone concentrations and demonstrated a sensitivity of ≈4.4 MHz/ppt and ≈4.3 MHz/ppt of acetone for solid and porous PDMS, respectively. Integrating PDMS and microwave‐based RIS systems provides a sensitive tool for tracking the interaction of acetone gas and PDMS and demonstrates this system's capability for sensitive gas detection. This study introduces a unique development in the wireless detection of VOCs and presents a compact and passive approach with enhanced sensitivity, making it suitable for monitoring the interaction of polymers and hazardous VOCs. This technology is particularly suited for use in challenging and hard‐to‐reach environments. [ABSTRACT FROM AUTHOR]

We demonstrate chip-scale sub-Doppler spectroscopy in an integrated and fiber-coupled photonic-metasurface device. The device is a stack of three planar components: a photonic mode expanding grating emitter circuit with a monolithically integrated tilt-compensating dielectric metasurface, a microfabricated atomic vapor cell, and a mirror. The metasurface photonic circuit efficiently emits a 130 μm wide (1 / e 2 diameter) collimated surface-normal beam with only −6.3 dB loss and couples the reflected beam back into the waveguide and connecting fiber, requiring no alignment between the stacked components. We develop a simple model based on light propagation through the photonic device to interpret the atomic spectroscopy signals and explain spectral features covering the full Rb hyperfine state manifold. The demonstration of waveguide-to-waveguide coupling through the vapor cell paves the way for atomic ensembles to be used as components in complex photonic integrated circuits, allowing the unique properties of atomic systems to be available for future highly miniaturized optical devices and systems. [ABSTRACT FROM AUTHOR]

A novel fluorescent nanofilm DBAP-ETTA has been developed for diethyl chlorophosphate (DCP) vapor detection with high sensitivity and selectivity. Its smooth, homogeneous structure and large Stokes shift enable significant fluorescence quenching upon DCP exposure. The protonation-based sensing mechanism makes it ideal for real-time, portable DCP vapor sensing. [ABSTRACT FROM AUTHOR]

Entangled multiphoton sources are essential for both fundamental tests of quantum foundations and building blocks of contemporary optical quantum technologies. While efforts over the past three decades have focused on creating multiphoton entanglement through multiplexing existing biphoton sources with linear optics and postselections, our work presents a groundbreaking approach. We observe genuine continuous-mode time-energy-entangled W-class triphotons with an unprecedented production rate directly generated through spontaneous six-wave mixing (SSWM) in a four-level triple-Λ atomic vapor cell. Using electromagnetically induced transparency and coherence control, our SSWM scheme allows versatile narrowband triphoton generation with advantageous properties, including long temporal coherence and controllable waveforms. This advancement is ideal for applications like long-distance quantum communications and information processing, bridging single photons and neutral atoms. Most importantly, our work establishes a reliable and efficient genuine triphoton source, facilitating accessible research on multiphoton entanglement. [ABSTRACT FROM AUTHOR]

The development of adsorbent materials for highly efficient iodine capture is in high demand from the perspective of ecological environment and human health. Herein, two covalent organic frameworks (COFs), JLNU-312 and JLNU-313, were successfully synthesized for iodine adsorption. The obtained JLNU-COFs possess high crystallinity and one-dimensional mesoporous channels. Iodine adsorption experiments demonstrated that both COF materials exhibit effective performance for iodine adsorption, with a maximum amount of up to 4.67 g g−1 for JLNU-312 and 2.47 g g−1 for JLNU-313. Moreover, both JLNU-COFs have good stability, reusability and iodine retention capacity. Theoretical calculations clearly show that the higher adsorption performance of JLNU-312 is also due to the strong interaction between the adsorbed iodine and the abundant triazine nitrogen-rich adsorption sites uniformly distributed in the pore. This work shows that effective iodine adsorbents can be achieved by introducing nitrogen-rich sites into the framework of COF materials. [ABSTRACT FROM AUTHOR]

Summary Contradictory evidence exists regarding the relevance of Péclet‐like gradients in leaf water isotopes, making it difficult to accurately predict variation in isotope composition. Here, we use H218O vapour labelling to directly test whether leaf water isotopes diffuse back into the xylem to be carried forward to more distal leaf portions. Backward diffusion has been assumed, due to observations of increasing enrichment towards the tip and outer edges of some leaves. Further complicating the selection of leaf water isotope models is the observation that some, but not all, leaves demonstrate a radial Péclet effect in bulk leaf water and that the hydraulic design of leaves may influence the development of isotope gradients in leaves. Carry‐forward of H218O vapour label was detected in the two monocot species assessed (oat and corn), but not in the two dicot species (foxglove and sunflower). Further, bulk leaf water measurements at differing transpiration rates indicated that a bulk leaf water Péclet effect was relevant for foxglove only. We conclude that both leaf hydraulic design and relative velocities of water within transport pathways influence leaf water isotope composition, reconciling seemingly contradictory previous results regarding the relevance of Péclet effects to leaf water isotopes. [ABSTRACT FROM AUTHOR]

Achieving highly selective, highly responsive detection of formaldehyde gas at ppb level at room temperature is highly challenging for air monitoring and life health observation. Therefore, in this paper, low-cost, easy-to-fabricate, highly responsive as well as highly selective Zn 2 SnO 4 /SnO 2 (ZTO/SnO 2) metal-oxide semiconductor gas sensors have been successfully prepared by using one-pot hydrothermal method. The results showed that the synergistic effect of the n-n heterojunction formed between ZTO/SnO 2 prepared by this method led to a substantial increase in the sensitivity to the target gases, and ZTO/SnO 2 -3 a higher response (291) to 100 ppm formaldehyde compared to the response values of pure samples of Zn 2 SnO 4 (20.4) and pure SnO 2 (6.99) at room temperature. In addition, the response value for formaldehyde reached about 16.5–295 times higher than that for other common hazardous gases (100 ppm) in our lives. The ZTO/SnO 2 -3 sample with 1 mol/L NaOH was homogeneous and small, exposing as much surface as possible, and the theoretical minimum detection limit was calculated to be 50 ppb. Therefore, the large specific surface area and active adsorption/interaction sites are favorable for gas sensing. This work provides an excellent way to prepare gas-sensitive characteristic sensors using NaOH to improve the surface structure. [ABSTRACT FROM AUTHOR]

This study investigates Margaret Cavendish's The Blazing World and Sor Juana's Primero sueño (First Dream) in relation to Elisabeth of Bohemia's inquiry about the soul-body union in her correspondence with René Descartes. Elisabeth's question was two-fold, epistemic as well as metaphysical, and the first aspect remains understudied. Her epistemic question is rendered in gendered terms, seeking a 'more precise' account of a female-bodied soul (like hers), allegedly more susceptible to fits of vapours and eager for philosophical meditations nonetheless. This study argues that Descartes's letters did not adequately address Elisabeth's epistemic question as such and proposes instead to turn to the aforementioned fictions for accounts of the female soul's pursuit of (self-)knowledge, by way of imaginary correspondence between the three early modern women on the rational soul in a female body. [ABSTRACT FROM AUTHOR]

Contamination of trace levels of volatile organic compounds (VOCs) in enclosed spaces is not usually a significant cause for concern; however, it can be relevant in the case of canine scent detection training as a canine's superior sense of smell makes them highly likely to detect low levels of contamination, contributing to inefficient training. Thus, herein, we address the need for a simple, low-cost, robust, vapochromic sensor to determine the cross-contamination of VOCs within closed containers, such as canine training aid kits. This study focuses on the development of a vapor sensor, which produces a rapid colorimetric change when a target chemical vapor is present. A pH indicator is used as the colorimetric dye and its incorporation into a sol–gel matrix on a paper substrate is confirmed via SEM characterization. The sensor's stability and performance is tested against exposure to various levels of sunlight and temperature. The design allows the sensor to present a clear and unambiguous visible response to the release of the volatile target within a closed container. It can be readily incorporated into existing training kits and functions as a straightforward reminder of when training aids need to be changed or a new containment system should be considered. [ABSTRACT FROM AUTHOR]

• An enhanced ejector-subcooler CO 2 transcritical refrigeration cycle is presented. • A parametric analysis and optimization of the enhanced cycle and the baseline cycle are carried out. • The results suggest the integration of the proposed cycle could achieve more compact and reliable systems. • The maximum COP improvements are computed as 11.7%-17.5% when the gas cooler outlet temperature ranges from 35 °C to 50 °C and the evaporating temperature is -40 °C. The main drawback associated with CO 2 refrigeration systems is related to their performance reduction during transcritical operation at warm climate conditions, which may be compensated by better cycle architectures such as the split-cycle with subcooling or the flash-tank configuration, among others. Specifically, the use of standard gas-ejectors together with parallel compressors provides even better efficiency improvements, not being able to use them with low-temperature evaporators to prevent the triple point inside the ejector. This paper proposes an enhanced cycle with a gas ejector for two-stage compressor architectures with vapor injection from the flash-tank, which is able to operate at low evaporating temperatures and that provides a greater performance improvement the more severe the climate conditions are. The methodology conducted is based on a thermodynamic analysis that includes parametric evaluation and cycle optimization, comparing the results to a conventional CO 2 transcritical cycle with flash-tank and dynamic vapor injection architecture. The main results show that a maximum Coefficient of Performance improvement of 17.5% is achievable for transcritical operation at -40 °C evaporating temperature. The compressor displacement capacity required with the enhanced cycle is up to 9% lower for the same refrigeration demand, reducing the electrical consumption as well as the compressor expenditure. Moreover, greater vapor injection mass flow rates are obtained by the gas-ejector injection with discharge temperature reductions up to 18%, enhancing the system reliability. [ABSTRACT FROM AUTHOR]

Understanding the short‐term responses of mesophyll conductance (gm) and stomatal conductance (gsc) to environmental changes remains a challenging yet central aspect of plant physiology. This review synthesises our current knowledge of these short‐term responses, which underpin CO2 diffusion within leaves. Recent methodological advances in measuring gm using online isotopic discrimination and chlorophyll fluorescence have improved our confidence in detecting short‐term gm responses, but results need to be carefully evaluated. Environmental factors like vapour pressure deficit and CO2 concentration indirectly impact gm through gsc changes, highlighting some of the complex interactions between the two parameters. Evidence suggests that short‐term responses of gm are not, or at least not fully, mechanistically linked to changes in gsc, cautioning against using gsc as a reliable proxy for gm. The overarching challenge lies in unravelling the mechanistic basis of short‐term gm responses, which will contribute to the development of accurate models bridging laboratory insights with broader ecological implications. Addressing these gaps in understanding is crucial for refining predictions of gm behaviour under changing environmental conditions. Summary statement: This review synthesises our current knowledge of short‐term responses of mesophyll conductance (gm) to changes in environmental conditions. Recent advances in measurement techniques for the detection of short‐term gm responses are described and points of caution are highlighted, such as the impact of vapour pressure deficit or when using stomatal conductance (gsc) as a proxy for gm. [ABSTRACT FROM AUTHOR]

The ever-increasing complexity and data volumes of numerical weather prediction demand innovations in the analysis and synthesis of operational forecast data. Here we show how dynamical thinking can offer directly applicable forecast information, taking as a case study the extreme northern Italy flooding of May 2023. We compare this event with long-lasting historical northern Italy rainfall events in order to determine (a) why it was so extreme, (b) how well it was predicted, and (c) how we may improve our predictions of such extremes. Lagrangian analysis shows, in line with previous work, that 48-hourly extreme rainfall in Italy can be caused by moist air masses originating from the North Atlantic; North Africa; and, to a lesser extent, eastern Europe, with compounding moisture contributions from all three regions driving the May 2023 event. We identify the large-scale precursors of typical northern Italy rainfall extremes based on geopotential height and integrated vapour transport fields. We show in European Centre for Medium-Range Weather Forecasts (ECMWF) operational forecasts that a precursor perspective was able to identify the growing possibility of the Emilia-Romagna extreme event 8 d beforehand – 4 d earlier than the direct precipitation forecast. Such dynamical precursors prove to be well suited for identifying and interpreting predictability barriers and could help build forecasters' understanding of unfolding extreme scenarios in the medium range. We conclude by discussing the broader implications and operational potential of dynamically rooted metrics for understanding and predicting extreme events, both in retrospect and in real time. [ABSTRACT FROM AUTHOR]

Current general circulation models struggle to capture the phase-partitioning of clouds accurately, both overestimating and underestimating the supercooled liquid substantially. This impacts the radiative properties of clouds. Therefore, it is of interest to understand which processes determine the phase-partitioning. In this study, microphysical-process rates are analysed to study what role each phase-changing process plays in low-level Arctic clouds. Several months of cloud-resolving ICON simulations using a two-moment cloud microphysics scheme are evaluated. The microphysical-process rates are extracted using a diagnostic tool introduced here, which runs only the microphysical parameterization using previously simulated days. It was found that the processes impacting ice are more efficient during polar night than polar day. For the mixed-phase clouds (MPCs), it became clear that phase changes involving the vapour phase dominated in contrast to processes between liquid and ice. Computing the rate of the Wegener–Bergeron–Findeisen process further indicated that the MPCs frequently (42 % of the time) seemed to be glaciating. Additionally, the dependence of each process on the temperature, vertical wind, and saturation was evaluated. This showed that, in particular, the temperature influences the occurrence and interactions of different processes. This study helps to better understand how microphysical processes act in different regimes. It additionally shows which processes play an important role in contributing to the phase-partitioning in Arctic low-level mixed-phase clouds. Therefore, these processes could potentially be better targeted for improvements in the ICON model that aim to more accurately represent the phase-partitioning of Arctic low-level mixed-phase clouds. [ABSTRACT FROM AUTHOR]

This article aims to examine a novel combined power and refrigeration system, using renewable and waste heat sources suitable for low-temperature applications. The present system is an integrated Kalina cycle and ejector refrigeration system to generate power and refrigeration simultaneously. To improve the vapour generation, the separator vapour fraction is used as a decision variable. Relative irreversibility and efficiency defect as two important parameters considered in this system for an investigation to identify the weaker components. The combined system generates power and refrigeration with two different mediums by the incorporation of the heat exchanger at the turbine exhaust. The novel system's energy and conventional exergy evaluation are carried out through Python Software. The optimum values of decision variables: turbine concentration, separator vapour fraction, entrainment ratio, expander ratio, split ratio and turbine concentration are identified using Python software from an opted range of variables. The maximum value of net power output, first law efficiency for power generation system, combined system, second law efficiency for power generation system, combined system, refrigeration effect and coefficient of performance are obtained as 113 kW, 8.85%, 11.83%, 93.44%, 81.29%, 38.07% and 0.118, respectively, at higher separator vapour fraction. Among the components considered in the combined power generation system, the condenser and LTRGN account for the higher exergy destruction rate of 30.41% and 25.53%. The coefficient of performance is maximized at a higher value of the refrigeration effect. The turbine pressure at the inlet is increased with increments in turbine work on choosing the higher value of the expander ratio. The higher exergetic value components are not emphasized to focus on improvement. [ABSTRACT FROM AUTHOR]

We report superionic conduction in a Mg2+-containing covalent organic framework (COF) at intermediate temperature in the absence of guest vapors. A COF containing Mg2+ carriers and polyethylene oxide (PEO) chains in its channels (TPB-PEO-9-COF-Mg) was synthesized. TPB-PEO-9-COF-Mg showed superionic conductivity above 10−4 S cm−1 under dry N2 at 160 °C. [ABSTRACT FROM AUTHOR]

The chip-scale hybrid optical pumping spin-exchange relaxation-free (SERF) atomic magnetometer with a single-beam arrangement has prominent applications in biomagnetic measurements because of its outstanding features, including ultrahigh sensitivity, an enhanced signal-to-noise ratio, homogeneous spin polarization and a much simpler optical configuration than other devices. In this work, a miniaturized single-beam hybrid optical pumping SERF atomic magnetometer based on a microfabricated atomic vapor cell is demonstrated. Although the optically thin Cs atoms are spin-polarized, the dense Rb atoms determine the experimental results. The enhanced signal strength and narrowed resonance linewidth are experimentally proven, which shows the superiority of the proposed magnetometer scheme. By using a differential detection scheme, we effectively suppress optical noise with an approximate five-fold improvement. Moreover, the cell temperature markedly affects the performance of the magnetometer. We systematically investigate the effects of temperature on the magnetometer parameters. The theoretical basis for these effects is explained in detail. The developed miniaturized magnetometer has an optimal magnetic sensitivity of 20 fT/Hz1/2. The presented work provides a foundation for the chip-scale integration of ultrahighly sensitive quantum magnetometers that can be used for forward-looking magnetocardiography (MCG) and magnetoencephalography (MEG) applications. [ABSTRACT FROM AUTHOR]

Material extrusion (MEX) is worldwide known as one of the most flexible additive manufacturing (AM) technologies for the fabrication of complex polymeric structures. However, the extremely high geometrical freedom has a price to pay: the presence of interlayer voids between consecutive extruded layers is the main backwards of MEX technology. Interlayer voids make 3D printed parts weaker (poor mechanical properties) compared to polymeric components fabricated by means of counterpart processes (i.e., injection molding). The present research work introduces a novel approach for the reduction of voids based on the layer-by-layer application of solvent vapor during the fabrication process, to smooth every single deposited layer. In this way, the new extruded layer has a greater area to bond with the previously extruded layer, resulting in an overall reduction of the porosity. The proposed approach is cost-effective, and it is based on the stop and go method enabled by MEX technologies: the fabrication process is paused after every layer, and when the solvent treatment is performed, the 3D printing process is resumed. The effectiveness of the layer-by-layer solvent vapor approach was evaluated, thereby resulting in a great reduction of the void density and average void area of 96%, and 79% respectively, and an increase of the wetting factor of 34%. Such findings pave the way for the exploitation of the proposed approach for the fabrication of complex structures with a reduced number of voids to be employed as structural components. [ABSTRACT FROM AUTHOR]

Exceptional points are the branch-point singularities of non-Hermitian Hamiltonians and have rich consequences in open-system dynamics. While the exceptional points and their critical phenomena are widely studied in the non-Hermitian settings without quantum jumps, they also emerge in open quantum systems depicted by the Lindblad master equations, wherein they are identified as the degeneracies in the Liouvillian eigenspectrum. These Liouvillian exceptional points often have distinct properties compared to their counterparts in non-Hermitian Hamiltonians, leading to fundamental modifications of the steady states or the steady-state-approaching dynamics. Since the Liouvillian exceptional points widely exist in quantum systems such as the atomic vapors, superconducting qubits, and ultracold ions and atoms, they have received increasing amount of attention of late. Here, we present a brief review on an important aspect of the dynamic consequence of Liouvillian exceptional points, namely the chiral state transfer induced by the parametric encircling the Liouvillian exceptional points. Our review focuses on the theoretical description and experimental observation of the phenomena in atomic systems that are experimentally accessible. We also discuss the ongoing effort to unveil the collective dynamic phenomena close to the Liouvillian exceptional points, as a consequence of the many-body effects therein. Formally, these phenomena are the quantum-many-body counterparts to those in classical open systems with nonlinearity, but hold intriguing new potentials for quantum applications. [ABSTRACT FROM AUTHOR]

A convenient, fast, selective, sustainable detection and capture of hydrochloric acid and ammonia vapours in the solid state with bare eye colour switching is observed by a robust microporous 2D zigzag Zn-MOF based material. Here ESIPT off/on based dual emission alteration has been employed for sensing. [ABSTRACT FROM AUTHOR]

The incorporation of ejectors into heat pump and refrigeration cycles has been the subject of growing interest, largely due to their simple structure, high reliability, and cost-effectiveness. This paper investigates the recent advancements in novel design concepts of ejector-enhanced vapor compression heat pump and refrigeration cycles. An overview of novel single-stage and two-stage compression cycles utilizing a single or multiple ejectors is provided. First, the system setup, operational principles, description, and figures of the existing schemes are provided. Second, the main results, such as the coefficient of performance (COP), volumetric heating capacity and exergy destruction, are discussed. In conclusion, the paper presents a coherent summary of the current developments, future prospects, and the current knowledge gap. A plethora of research is present in developing theoretical systems with high efficiency. However, experimental tests for real-life implementations are limited. This review aims to provide the reader with an overview of recent theoretical and experimental studies. [ABSTRACT FROM AUTHOR]

Compositional control over vapor–liquid–solid III–V ternary nanowires based on group V intermix (VLS IIIVxV1−x NWs) is complicated by the presence of a catalyst droplet with extremely low and hence undetectable concentrations of group V atoms. The liquid–solid and vapor–solid distributions of IIIVxV1−x NWs at a given temperature are influenced by the kinetic parameters (supersaturation and diffusion coefficients in liquid, V/III flux ratio in vapor), temperature and thermodynamic constants. We analyze the interplay of the kinetic and thermodynamic factors influencing the compositions of VLS IIIVxV1−x NWs and derive a new vapor–solid distribution that contains only one parameter of liquid, the ratio of the diffusion coefficients of dissimilar group V atoms. The unknown concentrations of group V atoms in liquid have no influence on the NW composition at high enough levels of supersaturation in liquid. The simple analytic shape of this vapor–solid distribution is regulated by the total V/III flux ratio in vapor. Calculating the temperature-dependent desorption rates, we show that the purely kinetic regime of the liquid–solid growth occurs for VLS IIIVxV1−x NWs in a wide range of conditions. The model fits the data well on the vapor–solid distributions of VLS InPxAs1−x and GaPxAs1−x NWs and can be used for understanding and controlling the compositions of any VLS IIIVxV1−x NWs, as well as modeling the compositional profiles across NW heterostructures in different material systems. [ABSTRACT FROM AUTHOR]

Fabrication of low-RF loss GaN-on-Si high electron mobility transistor stacks is critical to enable competitive front-end-modules for 5G and 6G applications. The main contribution to RF losses is the interface between the III-N layer and the HR Si wafer, more specifically the AlN/Si interface. At this interface, a parasitic surface conduction layer exists in Si, which decreases the substrate effective resistivity sensed by overlying circuitry below the nominal Si resistivity. However, a clear understanding of this interface with control of the parasitic channel is lacking. In this Letter, a detailed physical and electrical description of metalorganic chemical vapor deposition-grown AlN/Si structures is presented. The presence of a SiCxNy interfacial layer is revealed, and its importance for RF losses is shown. Through C–V and I–V characterization, an increase in the C concentration of this interfacial layer is linked to the formation of negative charge at the AlN/Si interface, which counteracts the positive charge present in the 0-predose limit. The variation of the TMAl predose is shown to allow precise tuning of the C composition and, consequently, the resulting interface charge. Notably, a linear relationship between the predose and the net interface charge is observed and confirmed by the fabrication of an AlN/Si sample with close to zero net charge. In addition, a higher Dit (∼ 2 × 10 12 c m − 2 ) for such compensated samples is observed and can contribute to low-RF loss. An exceptionally high effective resistivity of above 8 kΩ cm is achieved, corresponding to an RF loss below 0.3 dB/mm at 10 GHz. [ABSTRACT FROM AUTHOR]

This study explores the potential of 700‐nm‐thick heteroepitaxial α‐Ga2O3 thin films on c‐plane sapphire substrates for X‐ray detector applications. The crystal quality and optical bandgap of the heteroepitaxial α‐Ga2O3 thin films are comparable to those of high‐quality α‐Ga2O3 thin films. The α‐Ga2O3 thin film X‐ray detector with a metal–semiconductor–metal structure exhibits a charge neutral point shift, resulting in a short‐circuit current density of 9.07 nA cm−2 and an open‐circuit voltage of –1.2 V. The detector achieves the highest signal‐to‐noise ratio of 973 at 0 V, while the maximum sensitivity (14.7 μC Gyair−1 cm−2) occurs at 10 V. The proposed X‐ray detector demonstrates a reliable transient response and long‐term robustness, suggesting the promise of heteroepitaxial α‐Ga2O3 for low‐cost, high‐quality, large‐area X‐ray detectors. [ABSTRACT FROM AUTHOR]

We report on the synthesis and high ionic conductivity of a highly crystalline Mg2+-containing metal–organic framework (MOF) with Type A feature (i.e., anionic framework having Mg2+ as a counter cation). We synthesized Mg[Zr(C14H3O8)2] (SU-102-Mg) through ion exchange reaction. SU-102-Mg showed a high ionic conductivity of 3.6 × 10−5 S cm−1 (25 °C, under MeCN vapor). [ABSTRACT FROM AUTHOR]

A limited understanding regarding the underlying dynamics and mechanisms of material removal during continuous wave laser drilling has presented significant challenges in achieving precision and process control. To address this, we employed high-fidelity, in situ synchrotron x-ray imaging to reveal previously unknown material behaviors during continuous wave laser drilling with power modulation. Our findings highlight that high-aspect ratio drill holes are achieved when the laser modulation frequency falls within the range of 8–12 kHz, provided that the laser average power and modulation amplitude levels meet the specified limits. Under these conditions, we identified a material removal mechanism driven by incremental accumulation of recoil pressure that gradually pushes material upward from deep within the substrate to the surface. This mechanism manifested as a low-frequency fluctuation in the vapor depression depth, resulting in periodic instances of material ejection. Furthermore, our study underscores that rapid expansion of the melt pool and the widening of the drill hole opening can impede effective material removal by redirecting energy from material ejection to increasing the melt pool size. This investigation contributes essential insights into the subsurface dynamics involved in the drilling of high-aspect ratio holes, furthering our fundamental understanding of this intricate process. [ABSTRACT FROM AUTHOR]

A first cadmium copper selenite–bromide Cd7Cu2(SeO3)8Br2 (1) was obtained via chemical vapor transport reactions. The new compound is triclinic, P 1 ‾ , a = 5.3280(5) Å, b = 10.6190(12) Å, c = 11.4380(13) Å, α = 100.856(4)°, β = 93.321(4)°, γ = 91.021(4)°, V = 634.22(12) Å3, R1 = 0.027. 1 has no structural analogs and belongs to a new structure type. The structure of 1 can be described as a host-guest architecture. The host is the [Cd7(SeO3)8]2− interrupted framework, which consists of zigzag layers with a large aperture. The guests are copper bromide species. Thus, the formula can be written as [Cd7(SeO3)8]{Cu2Br2}. [ABSTRACT FROM AUTHOR]

This paper proposes a theoretical approach to discuss the relations among reality, chemists' interactions with it, and the resulting interpretation and representation of the acquired scientific knowledge. Taking into account that such relations are of semiotic nature, this paper aims at discussing in the light of Peirce's theory of signs different descriptions of chemical activity and chemical education proposed by Alex Johnstone and elaborated by other science educators. In order to discuss the contributions and limitations of the proposed theoretical framework, and considering its potential interest for chemical education, an example on the communication strategies for the content 'vapour pressure' found in twentieth-century general chemistry university textbooks is also presented. [ABSTRACT FROM AUTHOR]

Although allicin has potent antibiotic properties, its low stability, which is responsible for its persistent biological activity, has posed a significant challenge to its practical application in modern medicine. To harness the healing benefits of this phytochemical, known by humans for thousands of years, we propose a controlled in situ synthesis of allicin vapour near the site of infection. Considering the critical need for novel approaches to prevent pandemic scenarios caused by MDR bacteria, we suggest encapsulating and physically separating allicin precursors (substrate alliin and enzyme alliinase) in alginate-based films and spray-dried chitosan microparticles. The mechanical properties of the hydrogel films of various compositions were evaluated, as well as their ability to protect the encapsulated alliinase against thermal stress and control the overall rate of allicin release upon hydration. Furthermore, the non-contact antibacterial efficacy of free alliin/alliinase reaction mixture (aqueous solution) and three compartmentalised configurations, i.e. film-solution, film-particles, and double-film, were tested against selected bacterial strains, i.e. E. coli, S. epidermidis, and S. aureus. The results indicate that the formation of allicin vapour using the proposed compartmentalised systems addresses allicin's stability issues and provides better control over the rate of allicin production. The observed antibacterial effect was comparable with directly formed allicin using higher initial amounts of both substances, which is given by diffusion limitations associated with encapsulation. These findings illustrate the potential of compartmentalised systems in developing nature-based wound dressings for infection prevention and promoting healing. [ABSTRACT FROM AUTHOR]

The pulsed optically pumped (POP) atomic clock has demonstrated unexpected performance in terms of frequency stability and drift. However, it remains a huge challenge to make this type of atomic clock more compact. Herein, we report the design of a miniaturized physics package, which is equipped with a magnetron microwave cavity holding a vapor cell of 1.3 cm internal diameter. The Zeeman transition spectrum reveals that the microwave cavity resonates in TE011-like mode. Based on a low-noise testbed, we also quantitatively analyze the relaxation time, linewidth, and noise sources of the resulting POP atomic clock. The population and coherence relaxation time are measured to be 3.16(0.16) and 2.97(0.03) ms under the temperature of 333 K, which are compatible well with the theoretical calculation. The Ramsey signal shows a contrast of 35% and a linewidth of 192 Hz. The total volume of the physics package is about 44 cm3, including a layer of magnetic shielding. The short-term frequency stability is measured to be 4.8 × 10−13τ−1/2 (where τ is the averaging time), which is mainly limited by the relative intensity noise of the laser system. [ABSTRACT FROM AUTHOR]

Hydration by H 2 O clusters has been shown to be an important means of transporting metal complexes in hydrothermal vapours and low-density supercritical aqueous fluids. However, the effect of hydration on the transport of relatively volatile metal complexes such as those involving bismuth and chloride has not been evaluated. This effect is important to evaluate because bismuth is a key pathfinder element for gold in many intrusion-related gold ore-forming systems, where low-density supercritical aqueous fluids and vapour may play an important role in metal transport. Here, we present the results of experiments investigating the solubility of BiOCl(s) and the speciation of bismuth in HCl-bearing aqueous vapour and low-density supercritical aqueous fluids at temperatures between 250 and 400 °C and pressures of 5 to 296 bar. Two gaseous bismuth species formed in the HCl-bearing fluids (X (HCl) > 0.0005), namely BiCl 3 (g) and BiCl 3 (H 2 O) n (g). Our data clearly show that BiCl 3 (g) is highly volatile at low water fugacity (between 30 and 110 bar) and acts as an unhydrated gas molecule. At higher water fugacity, the gaseous BiCl 3 (g) reacts with water to form hydrated BiCl 3 (H 2 O) n (g) species. Significantly, the stability of hydrated bismuth chloride species, BiCl 3 (H 2 O) n (g), with low hydration numbers is lower than that of the unhydrated species, BiCl 3 (g), resulting in a decrease in bismuth solubility with increasing f (H 2 O). However, at a water fugacity great than 30–110 bar, that increases with increasing temperature, the hydration number and the solubility of hydrated species BiCl 3 (H 2 O) n (g) increase with increasing water fugacity or the density of the fluid. Consequently, unhydrated gaseous bismuth species increase in importance with increasing temperature and become dominant at temperatures > 450 °C in fluids that have low density (<0.10 g/cm3). Hydrated bismuth chloride species are dominant in fluids having higher density (0.10–0.34 g/cm3). The overarching conclusion of this study is that aqueous low-density supercritical fluids, which exsolve from magmas to form intrusion-related gold deposits, can transport bismuth in concentrations (up to hundreds ppm) sufficient to form economic deposits. [ABSTRACT FROM AUTHOR]

Modeling of moisture transfer in porous materials is typically partitioned into liquid transport and vapor diffusion. Coefficients for liquid transport are often derived from laboratory measurements of water absorption by partial immersion. Although the assumption that capillary liquid transport is dominant while vapor diffusion is negligible is a reasonable assumption for mineral-based materials, recent work indicates that it is not representative of water absorption in wood across the grain. This article builds on earlier work and develops an improved engineering model for liquid water transport in softwoods. The approach uses a constant liquid diffusivity value, relies primarily on ordinary hygrothermal property measurements, and partitions vapor and liquid transport in a practical way that is informed by current understanding of wood–water interactions. The model is optimized using one-dimensional simulations calibrated against measured water uptake across a range of softwood species. Laboratory measurements were conducted to investigate key properties of eastern white cedar, which had the highest relative error in a previous version of the model, and to examine the practicality and relevance of vacuum saturation and free saturation for southern yellow pine. The model accuracy is improved by paying closer attention to the moisture storage function and capillary saturation value. [ABSTRACT FROM AUTHOR]

Growing high‐quality crystals remains a necessary part of crystallography and many other techniques. This article tabulates and describes several techniques and variations that will help individuals grow high‐quality crystals in preparation for crystallographic techniques and other endeavors, such as form screening. The discussion is organized to focus on low‐tech approaches available in any laboratory. [ABSTRACT FROM AUTHOR]

To gain insight into shock–droplet interaction and detonation wave–droplet interaction in the real physical environment, two solvers named interTwoPhaseLSCentralFoam and interTwoPhaseLSReacCentralFoam are developed under the OpenFOAM® framework. Computations were conducted on the primary breakup of a droplet when subjected to a shock wave and detonation wave. The droplet breakup in shock–droplet interaction divides into two distinct stages when the shock wave is involved. The first stage is a shear-force dominating stage. In the latter stage, there is a high-pressure gradient, which is similar to a discontinuity inside the droplet, leading to the catastrophic breakup. The detonation wave-induced droplet breakup undergoes three stages: initial stage, stretching stage, and balance stage. In the initial stage, the droplet was impacted by the intense compression. Under the impact of the reflected wave on the windward surface, the droplet is continuously stretched, marking the stretching stage. Then, the structure of the parent droplet remains relatively unchanged throughout the detonation, known as the balance stage. During the detonation wave–kerosene droplet interaction, there is a decoupling of detonation wave in certain regions. As kerosene vapor initiates a reaction with the atmosphere and prevails, the detonation wave undergoes a localized re-initiation process behind the incident shock, creating a dual-wave configuration in its entirety. The detonation wave also experienced a shift of mode from hydrogen–air driven to kerosene–air driven. [ABSTRACT FROM AUTHOR]

In this paper, the ignition process of the plasma scalpel is characterized by means of numerical simulation, shadowgraphy, and voltage–current measurements. The ignition process involves two phases: the pre-breakdown phase and the breakdown phase. Our study shows that in the pre-breakdown phase, the vapor layer is first generated around the corners of the active electrode and then gradually extends to cover the entire active electrode. Once the active electrode is fully covered by the vapor layer, the electric field reaches a maximum of 7.3 × 106 V m−1, which can cause discharge in the vapor layer. At this moment, the thickness of the vapor layer is approximately 100 μm. In the breakdown phase, the maximum electron density reaches 1018–1019 m−3. The plasma dissipates about 60% of the total power which is up to 125 W, thus enabling efficient cutting. In addition, we simulate the discharge characteristics of cutting various biological tissues. The results show that under the same voltage level, the higher the conductivity of biological tissues, the greater the discharge current. The biological tissues act as ballast resistors in equivalent circuits. [ABSTRACT FROM AUTHOR]

A first cadmium copper selenite–bromide Cd7Cu2(SeO3)8Br2 (1) was obtained via chemical vapor transport reactions. The new compound is triclinic, P 1 ‾ , a = 5.3280(5) Å, b = 10.6190(12) Å, c = 11.4380(13) Å, α = 100.856(4)°, β = 93.321(4)°, γ = 91.021(4)°, V = 634.22(12) Å3, R1 = 0.027. 1 has no structural analogs and belongs to a new structure type. The structure of 1 can be described as a host-guest architecture. The host is the [Cd7(SeO3)8]2− interrupted framework, which consists of zigzag layers with a large aperture. The guests are copper bromide species. Thus, the formula can be written as [Cd7(SeO3)8]{Cu2Br2}. [ABSTRACT FROM AUTHOR]

Exceptional points are the branch-point singularities of non-Hermitian Hamiltonians and have rich consequences in open-system dynamics. While the exceptional points and their critical phenomena are widely studied in the non-Hermitian settings without quantum jumps, they also emerge in open quantum systems depicted by the Lindblad master equations, wherein they are identified as the degeneracies in the Liouvillian eigenspectrum. These Liouvillian exceptional points often have distinct properties compared to their counterparts in non-Hermitian Hamiltonians, leading to fundamental modifications of the steady states or the steady-state-approaching dynamics. Since the Liouvillian exceptional points widely exist in quantum systems such as the atomic vapors, superconducting qubits, and ultracold ions and atoms, they have received increasing amount of attention of late. Here, we present a brief review on an important aspect of the dynamic consequence of Liouvillian exceptional points, namely the chiral state transfer induced by the parametric encircling the Liouvillian exceptional points. Our review focuses on the theoretical description and experimental observation of the phenomena in atomic systems that are experimentally accessible. We also discuss the ongoing effort to unveil the collective dynamic phenomena close to the Liouvillian exceptional points, as a consequence of the many-body effects therein. Formally, these phenomena are the quantum-many-body counterparts to those in classical open systems with nonlinearity, but hold intriguing new potentials for quantum applications. [ABSTRACT FROM AUTHOR]