bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced light output power from AlGaN-based deep ultraviolet LEDs achieved by a four-in-one mesa structure
Authors: Zheng Xi , Wu Xiyang , Yang Renlong , Tong Changdong , Zhong Chenming , Gao Fengyun , Lin Yue , Chen Guolong , Lu Yijun , Chen Zhong , Guo Weijie
Published: August 2023

This study aimed to investigate the impact of mesa geometry on the light output characteristics of AlGaN-based 275 nm deep ultraviolet light-emitting diodes (DUV-LEDs). By dividing the original single-junction mesa into four parts and connecting them serially (four-in-one), high-voltage (HV) DUV-LEDs with rectangular, hexagonal, circular, triangular, and square submesas were realized, achieving significant enhancement of the light output power (LOP) and wall-plug efficiency (WPE). The LOP of HV DUV-LEDs with hexagonal submesas has been promoted substantially compared to that of the original DUV-LEDs. Among the investigated five different types of submesas, hexagonal-type HV DUV-LEDs can achieve the highest LOP and WPE due to the higher sidewall light extraction. Furthermore, it is also demonstrated that pulse current driving can reduce the self-heating effect of HV DUV-LEDs.
Clusters and bulky Lewis acid protected complexes with planar hexacoordinate beryllium and magnesium
Authors: Yan Gai-ru , Liu Yu-qian , Liu Xin-bo , Wang Meng-hui , Cui Zhong-hua , Pan Sudip
Published: August 2023

Planar hexacoordination (ph) is only rarely reported in the literature. So far, only a few neutral and cationic molecules possessing phE (E = C, Si, B, Al, Ga) in the most stable isomer are predicted theoretically. Present electronic structure calculations report hitherto unknown anionic planar hexcoordinate beryllium and magnesium, phBe/Mg, as the most stable isomer. Global minimum searches show that the lowest energy structure of BeC6M3− (M = Al, Ga) and MgC6M3− (M = Ga, In, Tl) is the D3h symmetric phBe/Mg clusters, where beryllium/magnesium is covalently bonded with six carbon centers and M is located in a bridging position between two carbon centers. These global minimum phBe/Mg clusters are highly kinetically stable against isomerization, facilitating the experimental confirmation by photoelectron spectroscopy. Noteworthy is the fact that the phBe/Mg center is linked with carbon centers through three 7c–2e delocalized σ bonds and three 7c–2e π bonds, making the cluster double aromatic (σ + π) in nature. The bonding between the Be/Mg and outer ring moiety can be best expressed as an electron-sharing σ-bond between the s orbital of Be+/Mg+ and C6M32− followed by three dative interactions involving empty pπ and two in-plane p orbitals of Be/Mg. Furthermore, Lewis basic M centers of the title clusters can be passivated through the complexation with bulky Lewis acid, 9-boratriptycene, lowering the overall reactivity of the cluster, which can eventually open up the possibility of their large-scale syntheses.
Effective modulation of lattice thermal conductivity in monolayer AlP3 by biaxial strain and external electric field
Authors: Li Wentao , Hou Weiwei
Published: August 2023

Tunable lattice thermal conductivity is a critical issue promoting thermoelectric performance of potential thermoelectric materials. Herein, the effects of biaxial strain and an external electric field on the lattice thermal conductivity of monolayer AlP3 have been investigated systematically by solving the phonon Boltzmann transport equation based on first-principles calculations. Our results imply that the lattice thermal conductivity of monolayer AlP3 can be effectively modulated in a wide range depending on the applied in-plane biaxial tensile strains or out-of-plane external electric fields. Once the biaxial tensile strain is applied to the monolayer, the lattice thermal conductivity exhibits an up-and-down behavior with an increase in the tensile strain. The maximum thermal conductivity is obtained at a tensile strain of 6%, and a surprising peak value of 13.8 times higher than that of the pristine monolayer can be achieved, whereas the lattice thermal conductivity of monolayer AlP3 is able to be further suppressed by applying an external electric field, and a minimum value of about 47.5% of the pristine one can be observed by utilizing an electric field of 0.06 eV/Å. Thus, this work highlights that biaxial strain combined with an external electric field can provide effective ways to realize robust thermal management for 2D triphosphides.
Response of a dusty plasma system to external charge perturbations
Authors: Sarkar Hitendra , Bora Madhurjya P.
Published: August 2023

The excitation of nonlinear wave structures in a dusty plasma caused by a moving external charge perturbation is examined in this work, which uses a 1D flux corrected transport simulation. The plasma responds uniquely to the different nature of the moving charge, depending on which, for small amplitude perturbations, pinned envelope solitons are generated and electrostatic dispersive ion-acoustic shock waves are formed for a large amplitude perturbation. The presence of dust particles is found to suppress the formation of dispersive shocks at a low velocity of the external charge debris. The results are also investigated theoretically as a solution to the generalized Gross–Pitaevskii equation, which broadly supports the simulation results.
A generalized Kirkwood implicit solvent for the polarizable AMOEBA protein model
Authors: Corrigan Rae A. , Thiel Andrew C. , Lynn Jack R. , Casavant Thomas L. , Ren Pengyu , Ponder Jay W. , Schnieders Michael J.
Published: August 2023

Computational simulation of biomolecules can provide important insights into protein design, protein-ligand binding interactions, and ab initio biomolecular folding, among other applications. Accurate treatment of the solvent environment is essential in such applications, but the use of explicit solvents can add considerable cost. Implicit treatment of solvent effects using a dielectric continuum model is an attractive alternative to explicit solvation since it is able to describe solvation effects without the inclusion of solvent degrees of freedom. Previously, we described the development and parameterization of implicit solvent models for small molecules. Here, we extend the parameterization of the generalized Kirkwood (GK) implicit solvent model for use with biomolecules described by the AMOEBA force field via the addition of corrections to the calculation of effective radii that account for interstitial spaces that arise within biomolecules. These include element-specific pairwise descreening scale factors, a short-range neck contribution to describe the solvent-excluded space between pairs of nearby atoms, and finally tanh-based rescaling of the overall descreening integral. We then apply the AMOEBA/GK implicit solvent to a set of ten proteins and achieve an average coordinate root mean square deviation for the experimental structures of 2.0 Å across 500 ns simulations. Overall, the continued development of implicit solvent models will help facilitate the simulation of biomolecules on mechanistically relevant timescales.
Neutral-to-ionic photoinduced phase transition of tetrathiafulvalene-p-chloranil by electronic and vibrational excitation: A real-time nuclear–electronic dynamics simulation study
Authors: Hanada Tatsuki , Uratani Hiroki , Nakai Hiromi
Published: August 2023

Tetrathiafulvalene-p-chloranil exhibits photoinduced phase transition (PIPT) between neutral (N) and ionic (I) phases, in which the constituent molecules are approximately charge-neutral and ionic, respectively. In addition to visible-light irradiation, which can induce both N → I and I → N PIPTs, infrared irradiation has been reported to induce the N → I PIPT. These results suggest that N → I and I → N PIPTs can be driven by electronic excitation, and the I → N PIPT can also be driven by vibrational excitation. However, the feasibility of the N → I PIPT using vibrational excitation remains an open question. In this study, we address this issue by simulating the PIPT processes using a nonadiabatic molecular dynamics approach combined with real-time electron dynamics at the level of a semiempirical quantum chemical model, density-functional tight binding. The results show the importance of vibronic interactions in the PIPT processes, thereby suggesting the possibility of N → I PIPT by vibrational excitations with infrared irradiation.
Controlling second-mode oblique breakdown in high-speed boundary layers using streak: A direct numerical simulation study
Authors: Zhou Teng , Lu Yuhan , Liu Zaijie , Yan Chao
Published: August 2023

The suppression effect of streaks on the second mode has been studied by the stability analysis in the past decade. In the present study, we conduct direct numerical simulations (DNS) to investigate the direct nonlinear control in the complete laminar-to-turbulence transition scenario within a high Mach number supersonic boundary layer. Our study aims to provide a comprehensive understanding of the mechanisms underlying the influence of streaks on the transition of high-speed boundary layers. Our work demonstrates the effective control effect of the streaks generated by blowing and suction strips on laminar-to-turbulence transition via the second-mode oblique breakdown at a Mach number 4.5 high-speed boundary layer using DNS. Modal analysis, nonlinear disturbance formulation, and stability analysis are used to provide insight into the stabilization effect of control streaks. Crucially, the role of three-dimensional control modes and mean-flow distortion generated by the control streak are investigated. Our findings indicate that both mean-flow distortion and three-dimensional control modes effectively stabilize the fundamental oblique second mode, particularly when the amplitude of control streaks is strong.
Coherent fluctuations in a partially magnetized small magnetron discharge operating on molecular nitrogen
Authors: Przybocki Ryan C. , Cappelli Mark A.
Published: August 2023

We report experimental data on rotating plasma disturbances in a quasi-steady direct-current magnetron discharge operating with molecular nitrogen at pressures of 27, 40, 67, and 133 Pa. Experiments with a segmented anode measuring the local current flow reveal up to 12 coherent structures (“spokes”) propagating in the +E×B and −E×B azimuthal directions. The current–voltage characteristics are studied and found to follow a negative resistance profile at the lower discharge currents. The existence of coherent structures and the number of spokes observed depend on the discharge current and operating pressure. Lower pressures are more favorable to the retrograde −E×B spoke rotation, which is observed in the 27, 40, and 67 Pa discharges. The results are interpreted with a gradient-driven drift wave model, and using the dispersion relation, we show that the propagation direction depends on the orientation of the local electric field within the plasma. Using an electron fluid model, we show how experimental conditions can lead to field reversals that generate −E×B spoke rotation in the lower pressure discharges.
Effects of dilute low molecular weight poly(ethylene oxide) solutions in immiscible radial viscous fingering instabilities
Authors: Lee Young H. , Wang Jingyi , Gates Ian D.
Published: August 2023

We experimentally study the effects of normal stress differences in the immiscible radial viscous fingering instability in a Hele–Shaw cell. Dilute low molecular weight poly(ethylene oxide) (PEO) solutions are used as the displaced fluid to focus on elastic effects without shear-thinning behavior. The molecular weight of PEO is varied to investigate the effects of normal stress differences. The experimental observations reveal that nonmonotonic and opposing effects are evident depending on the molecular weight of the PEO and the stage of the radial viscous fingering evolution. Decreases in the PEO molecular weight reduce the number of fingers and widen the finger width in the early stage. However, the increase in the PEO molecular weight promotes tip splitting and narrows finger width in the early stage but suppresses tip splitting in the intermediate stage. Weissenberg numbers are estimated at different stages of radial viscous fingering instabilities. Tip splitting occurs at the highest Weissenberg number covered in this study and suppression of tip splitting is observed at intermediate Weissenberg numbers. At low Weissenberg numbers, we observe an increased finger width and a reduced number of fingers.
Effects of doping concentration on bond length and bond energy studied by Raman shift
Authors: Yang Xuexian , Dong ZhiLi , Sun Chang Q.
Published: August 2023

Based on the correlation between Raman shift and bond parameters, and further combined with experimental values of the Raman shift composition effect, the relationship between the composition and bond parameters of the 2D-M1−xM′xX2 and 2D-MX′2xX2(1−x) alloy materials was established. Numerical reproduction of the measurements clarified that the host atom phonons involved interaction with all of its z neighbors, whereas the doping atom phonon only involved interaction with a dimer. The doping of large atoms resulted in an elongation of the bond length, an increase in the equivalent coordination number, and enhancement of the binding energy. The doping of small atoms led to a contraction of the bond length, a decrease in the equivalent coordination number, and a weakening of binding energy. By quantifying the relationship between composition and bond parameters from Raman shifts, a deep understanding of two-dimensional alloy properties can be achieved.
Impact of unintentional Sb in the tensile InAs layer of strain-balanced type-II InAs/InAsSb superlattices grown on GaSb by molecular beam epitaxy
Authors: Milosavljevic Marko S. , Webster Preston T. , Johnson Shane R.
Published: August 2023

The impact of unintentional incorporation of Sb in the tensile InAs layer of type-II strain-balanced InAs/InAsSb superlattices is investigated. Several coherently strained midwave and longwave superlattices are grown on (100) GaSb substrates by molecular beam epitaxy and examined using x-ray diffraction and temperature-dependent photoluminescence spectroscopy. The zero-order diffraction angle provides the average Sb mole fraction of the strain-balanced superlattice period. Analysis of the higher order diffraction angles, along with the individual layer growth times and strain, provides the InAs and InAsSb layer thicknesses. Analysis of the photoluminescence measurements provides the ground-state bandgap of the superlattice, which along with simulations of the ground-state energies of the electrons and holes using a Kronig–Penney model, specify how the Sb is distributed between the tensile and compressive layers of the period and ultimately the quantity of unintentional Sb in the InAs layer. The unintentional Sb mole fractions observed in the tensile InAs layers are 1.9% for midwave and 1.2% for longwave. When compared to superlattices with the same period and no Sb in the tensile layer, the presence of unintentional Sb blue-shifts the 77 K temperature cutoff wavelength from 6.3 to 5.3 μm for midwave and from 18.8 to 12.0 μm for longwave.
Understanding how metal-nitride ferroelectrics switch their polarization
Authors: Wilson Mark
Published: August 2023

Transmission electron microscopy images and first-principles calculations suggest that the atoms adopt a disordered but low-energy configuration that facilitates the switching.
Embracing imperfection for quantum technologies
Authors: Anderson Christopher P. , Awschalom David D.
Published: August 2023

Solid-state spin qubits unlock applications in nanoscale quantum sensing and are at the forefront of creating distributed, long-distance entanglement that could enable a quantum internet.
Future regional increases in simultaneous large Western USA wildfires
Authors: McGinnis Seth , Kessenich Lee , Mearns Linda , Cullen Alison , Podschwit Harry , Bukovsky Melissa
Published: August 2023

Background Wildfire simultaneity affects the availability and distribution of resources for fire management: multiple small fires require more resources to fight than one large fire does. Aims The aim of this study was to project the effects of climate change on simultaneous large wildfires in the Western USA, regionalised by administrative divisions used for wildfire management. Methods We modelled historical wildfire simultaneity as a function of selected fire indexes using generalised linear models trained on observed climate and fire data from 1984 to 2016. We then applied these models to regional climate model simulations of the 21st century from the NA-CORDEX data archive. Key results The results project increases in the number of simultaneous 1000+ acre (4+ km2) fires in every part of the Western USA at multiple return periods. These increases are more pronounced at higher levels of simultaneity, especially in the Northern Rockies region, which shows dramatic increases in the recurrence of high return levels. Conclusions In all regions, the models project a longer season of high simultaneity, with a slightly earlier start and notably later end. These changes would negatively impact the effectiveness of fire response. Implications Because firefighting decisions about resource distribution, pre-positioning, and suppression strategies consider simultaneity as a factor, these results underscore the importance of potential changes in simultaneity for fire management decision-making.
Exploring the CaseScaling Up Sustainability: The Case of Big Wheel Burger
Authors: L.M. Coughlan , R. Dodds
Published: August 2023

Introduction

The fast-food industry is notorious for negatively impacting the environment with single-use packaging, high energy use, food waste, water contamination, and emissions. This case illustrates how one company is scaling up sustainability by turning profit upside down to ensure its community is benefiting from its growth. Students will get insights into the challenges, solutions, and benefits of operating and scaling a fast-food chain with sustainability at its core.

Big Wheel Burger is trailblazing scaling sustainable fast-food restaurants. This case will outline how a business model can be shifted to positively impact the community while maintaining profiles, keeping staff on a decent wage, and engaging customers on the journey.
Critical Assessment 43: Microstructural and mechanical properties of friction stir additively fabricated SiC-Reinforced AA6061 build
Authors: Choudhury Smrity , Das Rahul , Sethi Durjyodhan , Roy Joydeep , Roy Barnik Saha
Published: August 2023

Friction stir additive manufacturing was employed to fabricate a SiC-reinforced AA6061 composite. The tool with a pin length of 4.5 mm (plunge depth of 50% into the lower layer thickness) was used for the experiment. The stir zone consisted of fine, equiaxed grains due to dynamic recrystallisation. Variations in grain size, as well as changes in precipitate distribution, size, and morphology, were detected along the build direction. Hardness and tensile strength varied across layers, with the top slice having the greatest values of 104.2 HV and 268.4 MPa, respectively. Notably, the FSAM build demonstrated improved ductility with a maximum of 58.98%, mostly ascribed to fragmentation and partial loss of grain-boundary phases, as well as strong interfaces that delayed necking.
Early proteostasis of caveolins synchronizes trafficking, degradation, and oligomerization to prevent toxic aggregation
Authors: Morales-Paytuví Frederic , Fajardo Alba , Ruiz-Mirapeix Carles , Rae James , Tebar Francesc , Bosch Marta , Enrich Carlos , Collins Brett M. , Parton Robert G. , Pol Albert
Published: August 2023

Caveolin-1 (CAV1) and CAV3 are membrane-sculpting proteins driving the formation of the plasma membrane (PM) caveolae. Within the PM mosaic environment, caveola assembly is unique as it requires progressive oligomerization of newly synthesized caveolins while trafficking through the biosynthetic-secretory pathway. Here, we have investigated these early events by combining structural, biochemical, and microscopy studies. We uncover striking trafficking differences between caveolins, with CAV1 rapidly exported to the Golgi and PM while CAV3 is initially retained in the endoplasmic reticulum and laterally moves into lipid droplets. The levels of caveolins in the endoplasmic reticulum are controlled by proteasomal degradation, and only monomeric/low oligomeric caveolins are exported into the cis-Golgi with higher-order oligomers assembling beyond this compartment. When any of those early proteostatic mechanisms are compromised, chemically or genetically, caveolins tend to accumulate along the secretory pathway forming non-functional aggregates, causing organelle damage and triggering cellular stress. Accordingly, we propose a model in which disrupted proteostasis of newly synthesized caveolins contributes to pathogenesis.
CIPM key comparison CCPR-K1.a.2017 for spectral irradiance 250 nm to 2500 nm. Final report
Authors: Khlevnoy B B , Solodilov M V , Kolesnikova S S , Otryaskin D A , Pons A , Campos J , Shin D J , Park S , Obein G , Valin M H , Vissière A , Dai C , Wu Z , Wang Y , Li L , Lin Y , Yoon H , Gibson C , Liu Y , Manson P , Atkinson E , Zama T , Shitomi H , Goodman T , Servantes W , Gamouras A , Woods D J , Sperfeld P , Pape S
Published: August 2023

Main text

This report describes the Key Comparison of the Consultative Committee for Photometry and Radiometry CCPR-K1.a.2017 for Spectral Irradiance in the wavelength range of 250 nm to 2500 nm. Tungsten quartz halogen lamps of the FEL type (1000 W) were used as artefacts. Each participant used its own set of lamps. The star scheme of measurements was applied with the sequence participant - pilot - participant. Twelve National Metrology Institutes participated in the comparison. Each participant's measurement data were based on a totally independent spectral irradiance scale realisation. VNIIOFI (the Russian Federation) served as a pilot. The measurements were carried out from 2017 - 2020.

The analysis of the comparison was performed following the step-by-step approach described in Appendix B of the Guidelines for CCPR Key Comparison Report Preparation (CCPR-G2 Rev.4). The key comparison reference values (KCRV) were calculated independently at each wavelength as the weighted means with cut-off. The measurement data of all participants were used for the KCRV excluding just a few outliers in the wavelength range of 1700 nm to 2500 nm. The relative uncertainties of the KCRV were minimal, 0.08 %, at the wavelengths of 900 nm to 1500 nm and increasing towards the limits of the spectral range up to 0.28 % at 250 nm and 0.20 % at 2500 nm. Consistency checks were satisfied at 17 of the 28 measured wavelengths, but failed at 11 wavelengths, mostly in the infrared range. For the latter wavelengths the Mandel-Paule method was applied resulting in an additional uncertainty that varied depending on wavelength from 0.11 % to 0.89 %.

In general, the measurement uncertainties submitted by the participants in this comparison were less than those submitted in the previous CCPR-K1.a comparison. This is evidenced by the values of the cut-off, which had decreased at all wavelengths by a factor of 1.2 to 3.0 depending on wavelength. However, only for seven participants the degrees of equivalence do not exceed the expanded uncertainties at almost all wavelengths. About 80 % of all results (all participants at all wavelengths) agree with the KCRV within 1 % over the whole spectral range and within 0.7 % in the visible, which is comparable with the results of the previous CCPR-K1.a comparison.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Comparison report between NIM and CMS of the ITS-90 realization at the triple point of argon
Authors: Sun Jianping , Tsai Shu-Fei , Li Ting
Published: August 2023

Main text

The APMP key comparison APMP.T-K3.6 was initiated on the request of the Center for Measurement Standards, Taiwan (CMS) to link their standards to the Consultative Committee for Thermometry (CCT) Key Comparison (KC) and facilitate the CMS CMC submission. National Institute of Metrology, China (NIM) provided the linkage to the CCT-K3 at the temperature of the triple point of argon. In the APMP.T-K3.6, one standard platinum resistance thermometer (SPRT) was chosen as the transfer instruments, calibrated at the triple point of argon. The comparison was carried out in a participant-pilot-participant sequence where NIM served as the pilot. The linkage was based on the temperature of CMS reference Ar fixed point relative to the average (ARV) of CCT-K3 at the Ar fixed point via the difference in temperature between the NIM reference Ar fixed point and NIM reference Ar fixed point (links to the ARVs of the CCT-K3). The temperature differences between the standards of CMS and the ARVs of the CCT-K3 were within the evaluated comparison uncertainties of the ATPM.T-K3.6. This report provides detailed information on the comparison results, linkage mechanism, and the Degree of Equivalence of the CMS relative to the institutes having participated in the CCT-K3.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Novel polysilicon in resisting thermal-evaporation Al-electrode damage and its application in back-junction passivated contact p-type solar cells
Authors: Zeng Yuheng , Liu Zunke , Liao Mingdun , Liu Wei , Yang Zhenhai , Ye Jichun
Published: August 2023

In preparing tunnel oxygen passivation contact (TOPCon) solar cells, the metallization process often causes damage to passivation performance. Aiming to solve the issue, we investigated the advantages of the novel polysilicon, i.e. the carbon (C) or nitrogen (N) doped polysilicon, in resisting metallization damage. Our study reveals that C- or N-doped polysilicon does mitigate the passivation damage caused by the physical-vapor deposition metallization processes, i.e. the decrease in implied open-circuit voltage (iV
oc) and the increase in recombination current (J
0) are both suppressed. For the novel polysilicon samples suffered metallization, the decrease of iV
oc was only ∼−1 mV, and the increase of J
0 < 1 fA cm−2; in contrast, the decrease of iV
oc of the standard polysilicon samples was −7 mV, and the increase of J
0 was ∼6 fA cm−2. In addition, we also explored the difference between the finger-metal and the full-metal metallization, showing that the finger-metal has less passivation damage due to the smaller contact area. However, the free energy loss analysis indicates that the advantage of the novel polysilicon in resisting metallization damage is overshadowed by the disadvantage of the higher contact resistivity when finger-metal electrodes are used. Numerical simulations prove that the efficiency of the solar cell with novel polysilicon still shows >0.2% absolute efficiency higher than that with the standard polysilicon, reaching 26% when full-metal electrodes by thermal evaporation.
Investigating the Multiband Nonthermal Radiative Properties of HESS J1420−607
Authors: Tian Shiting , Zhou Liancheng , Gong Yunlu , Wu Keyao , Fang Jun , Yu Huan
Published: August 2023

HESS J1420−607 is a γ-ray emitting source associated with the pulsar wind nebula (PWN) powered by the energetic pulsar PSR J1420−6048. Based on 14 yr of data obtained with the Fermi Large Area Telescope, we re-analyzed its GeV γ-ray radiative properties, resulting in detailed spectra obtained within the band 10–200 GeV. Moreover, we use a one-zone time-dependent model for the multiband nonthermal emission from pulsar wind nebulae to investigate the radiative properties of the nebula associated with HESS J1420−607. Assuming that the electrons/positrons are injected into the PWN with a broken power law spectrum with indexes of ∼1.6 and ∼2.7, as well as a break Lorentz factor of ∼5 × 106, the results indicate that the multi-wavelength spectral energy distribution is consistent with the detected fluxes in both X-rays and γ-rays. The results support that the γ-rays detected can be produced via inverse Compton scattering of the energetic electrons/positrons within the PWN.
Analysing the temporal amplitude and average output power distribution in the mode-locked regions of an erbium-doped figure-eight fibre laser (theoretical and experimental results)
Authors: González-Galicia M A , Lozano-Crisóstomo N , Meneses F C De , Reyes-Ramírez B
Published: August 2023

The noise like pulses (NLPs) are ultrashort light pulses that present very complex dynamics, they are a particular case of the multiple light pulses generated by the partial mode-locked regime. These ultrashort light pulses exhibit very complex behaviour in amplitude and width, in the temporal domain and subsequently in the frequency domain. In this paper we present a theoretical and experimental analysis of temporal amplitude distribution of NLPs within the mode-locked regions of an erbium-doped figure-eight Fibber laser. The mode-locked regions were studied at different settings of the four polarization controllers (HWR1, QWR1) in the ring section and in the nonlinear optical loop mirror (HWR2, QWR2, NOLM) of the fibre laser cavity. We found a wide variety of values of the temporal amplitude of NLPs. The experimental results of the temporal amplitude are compared with simulations generated with the theoretical model based on the theory of polarization of light and the theoretical model of the NOLM. Also, we discovered experimentally that the theoretical model performs well in predicting the complex dynamics of the temporal distribution of amplitude. Finally, we experimentally discovered that the average power output distribution of the cavity has a behaviour which is close to proportional to the temporal amplitude distribution. We analyse NLPs with a carrier wavelength of 1562 nm with typical duration of

τ
⩽
10

ns and a repetition rate of 0.9 MHz.
A hybrid mechanism of 3D optical trapping of particles immersed in a cold buffer gas
Authors: Krasnov I V
Published: August 2023

A novel mechanism of the formation of a deep optical superlattice (OSL) for three-dimensional (3D) trapping of resonant impurity atoms immersed in a transparent cold buffer gas is proposed and investigated theoretically. This mechanism is associated with the joint action of two factors of different physical nature: rectification effect of the gradient force of light pressure and effect of the light induced drift (LID) of atoms (a consequence of the difference in gas-kinetic cross sections of excited and unexcited atoms). Such a situation can be realised when a gas mixture is irradiated by a bichromatic combined light beam which is a special coaxial superposition of cosine-Gaussian optical beams. Here, the RcGF creates a periodic 1D array of deep potential wells (OSL) along the beam axes, and an effective force, causing LID, pulls resonant particles into the combined light beam and provides their transverse (with respect to the beam axes) confinement in OSL. As a result, there can occur a giant accumulation of impurity particles in the OSL cells, accompanied by a strong spatial particle localization far away from the walls of the reservoir, in which the gas mixture is located.
Atomic-scale electromagnetic theory bridging optics in microscopic world and macroscopic world
Authors: Li 李 Zhi-Yuan 志远 , Chen 陈 Jian-Feng 剑锋
Published: August 2023

Atoms in the microscopic world are the basic building blocks of the macroscopic world. In this work, we construct an atomic-scale electromagnetic theory that bridges optics in the microscopic and macroscopic worlds. As the building block of the theory, we use the microscopic polarizability to describe the optical response of a single atom, solve the transport of electromagnetic wave through a single atomic layer under arbitrary incident angle and polarization of the light beam, construct the single atomic layer transfer matrix for light transport across the atomic layer. Based on this transfer matrix, we get the analytical form of the dispersion relation, refractive index, and transmission/reflection coefficient of the macroscopic medium. The developed theory can handle single-layer and few-layers of homogeneous and heterogeneous 2D materials, investigate homogeneous 2D materials with various vacancies or insertion atomic-layer defects, study compound 2D materials with a unit cell composed of several elements in both the lateral and parallel directions with respect to the light transport.
High efficient Raman sideband cooling and strong three-body recombination of atoms
Authors: Li 李 Yuqing 玉清 , Liu 刘 Zhennan 震南 , Wang 王 Yunfei 云飞 , Wu 武 Jizhou 寄洲 , Liu 刘 Wenliang 文良 , Fu 付 Yongming 永明 , Li 李 Peng 鹏 , Ma 马 Jie 杰 , Xiao 肖 Liantuan 连团 , Jia 贾 Suotang 锁堂
Published: August 2023

We report a highly efficient three-dimensional degenerated Raman sideband cooling (3D dRSC) that enhances the loading of a magnetically levitated optical dipole trap, and observe the strong atom loss due to the three-body recombination. The 3D dRSC is implemented to obtain 5 × 107 Cs atoms with the temperature of ∼ 480 nK. The cold temperature enables 1.8 × 107 atoms loaded into a crossed dipole trap with an optimized excessive levitation magnetic gradient. Compared to the loading of atoms from a bare magneto-optical trap or the gray-molasses cooling, there is a significant increase in the number of atoms loaded into the optical dipole trap. We derive for the three-body recombination coefficient of L
3 = 7.73 × 10−25 cm6/s by analyzing the strong atom loss at a large scattering length of 1418 Bohr radius, and discover the transition from the strong three-body loss to the dominant one-body loss. Our result indicates that the lifetime of atoms in the optical dipole trap is finally decided by the one-body loss after the initial strong three-body loss.
Theoretical study of (e,2e) triple differential cross section of 1b3g orbital of ethylene by vibrational multi-center distorted-wave method
Authors: Wang 王 Zhenpeng 振鹏 , Gong 宫 Maomao 毛毛 , Li 李 Xingyu 星宇 , Zhang 张 Songbin 松斌 , Chen 陈 Xiangjun 向军
Published: August 2023

The vibrational motions are usually neglected when calculating (e,2e) triple differential cross sections (TDCSs) of molecules. Here, multi-center distorted-wave method (MCDW) has been modified by including molecular vibrations. This vibrational MCDW method is employed to calculate the TDCSs of 1b3g orbital of ethylene at low (100 eV) and medium (250 eV) incident electron energies in coplanar asymmetric kinematic condition. The results show that molecular vibrations significantly influence the angular distributions of the TDCSs, especially in the binary region along momentum transfer near the Bethe ridge.
Direct preemptive stabilization of

m
,
n
=
2
,
1

neoclassical tearing modes by electron cyclotron current drive in the DIII-D low-torque ITER baseline scenario
Authors: Bardóczi L. , La Haye R.J. , Strait E.J. , Logan N.C. , Smith S.P. , Richner N.J. , Callen J.D.
Published: August 2023

We report the first preemptive direct stabilization of

m
,
n
=
2
,
1

neoclassical tearing modes (NTMs) in DIII-D low-torque ITER baseline scenario plasmas by electron cyclotron waves. These experiments strongly support that the observed stabilization is achieved by replacing the missing bootstrap current in the island by electron cyclotron current drive (ECCD). These plasmas (with and without ECCD) are stable to 2,1 NTMs when the differential rotation between the q = 1 and q = 2 surfaces (

Δ

f

1
,
2

) is sustained above a critical value (

Δ

f

CRIT

≈
1

 kHz), but those evolving to low differential rotation (

Δ

f

1
,
2

<
Δ

f

CRIT

) routinely develop a disruptive 2,1 island at the time and frequency of a sawtooth precursor. Preemptive, local and direct stabilization by ECCD is tested by scanning the current drive amplitude and location inside and outside of the q = 2 rational surface shot by shot. Analysis of only low differential rotation time windows, i.e. when stabilization from

Δ

f

1
,
2

is absent, shows focused ECCD at q = 2 prevents the onset of 2,1 NTMs. These results are important, as they give the first demonstration of disruptive NTM control by ECCD in the plasma scenario planned for ITER.
Poles of hydrodynamic spectral functions and Einstein–Helfand formulas for transport coefficients
Authors: Mabillard Joël , Gaspard Pierre
Published: August 2023

The local-equilibrium approach to transport processes is related to an approach based on time-dependent correlation functions and their associated spectral functions characterizing the equilibrium fluctuations of particles, momentum and other densities. On the one hand, transport coefficients are calculated with the Einstein–Helfand formulas derived in the local-equilibrium approach. On the other hand, the poles of the spectral functions at complex frequencies give the damping rates of the hydrodynamic modes. Since these rates also depend on the transport coefficients, their values can be compared to the predictions of the local-equilibrium approach. This comparison is systematically carried out for a hard-sphere fluid by numerically computing the transport coefficients, the spectral functions and their poles as a function of the wave number in the hydrodynamic limit. The study shows the consistency between the two approaches for the determination of transport properties.
H- beam formation simulation in negative ion source for CERN's Linac4 accelerator
Authors: Vnuchenko A. , Lettry J. , Mochalskyy S. , Wünderlich D. , Fantz U. , Lindqvist M. , Revel A. , Minea T.
Published: August 2023

The caesiated surface negative ion (H-) source is the first element of CERN's LINAC4 a linear injector designed to accelerate negative hydrogen ions to 160 MeV. The IS03 ion source is operated at 35 mA beam intensity and reliably feeds CERN's accelerator chain, H- ions are generated via plasma volume and caesiated molybdenum (Cs-Mo) plasma electrode surface mechanisms. Studying the beam extraction region of this H- ion source is essential for optimizing the H- production. The 3D Particle-in-cell (PIC) Monte Carlo (MC) code ONIX (Orsay Negative Ion eXtraction [1]), written to study H- beam formation processes in neutral-beam injectors for fusion, has been adapted to single aperture accelerator H- sources. The code was modified to match the conditions of the beam formation and extraction regions of the Linac4 H- source [2]. A set of parameters was chosen to characterize the plasma and to match the specific volume and surface production modes. Simulated results of the extraction regions are presented and benchmarked with experimental results obtained at the Linac4 test stand [3].
Pushed to finance? Assessing technology export as a motivator for coal finance abroad
Authors: Manych Niccolò , Egli Florian , Ohlendorf Nils , Schmidt Tobias S , Steffen Bjarne , Stünzi Anna , Steckel Jan Christoph
Published: August 2023

The construction of new coal-fired power plants is frequently financed by banks from abroad. Recent studies suggest that the opportunity to export technology is a relevant ‘push factor’ for such financing activities. In this paper, we provide first quantitative evidence for this hypothesis on a global scale. We construct a novel dataset that tracks both public and private financial involvement on a coal unit level, including information on equipment manufacturers and service providers. The findings indicate that financial institutions from various countries, including China, Japan, South Korea, and Western nations provide loans to coal units overseas. These finance flows, particularly from publicly owned banks, are accompanied by technology exports from the same country. Complementing our quantitative analysis with semi-structured interviews, we find indications that political economy factors, such as public banks’ requirement for participation of domestic firms in financing deals and the unlocking of export business opportunities for domestic industries in financing countries, contribute to this correlation. Our findings highlight the importance of financing countries and their domestic industries for low-carbon transitions globally.
A maladaptive parental effect: offspring survival decreases with maternal over-condition in an amphibian
Authors: Harmon Emily A , Li Tianxiu , Kelly Patrick W , Chen Catherine , Pfennig David W , Pfennig Karin S
Published: August 2023

Parental effects are often considered an evolved response, in which parents transmit information about the environment to enhance offspring fitness. However, these effects need not be adaptive. Here, we provide a striking example by presenting evidence that overfeeding of adult Mexican spadefoot toads, Spea multiplicata, is associated with decreased offspring survival. After a temporary change to their standard feeding regimen, S. multiplicata in our captive colony developed a much higher body condition (i.e. body mass for a given body length) than those in the wild. We analysed data from three subsequent experiments and found that although the body condition of a father was positively correlated with tadpole survival, mothers with a higher condition had lower tadpole survival. Our study highlights how obesity can negatively impact future generations via maladaptive maternal effects. Such effects could be especially likely for animals living in variable environments (such as spadefoots) that have evolved ‘thrifty phenotypes’ that make them prone to obesity. Our study also illustrates how husbandry conditions typically regarded as beneficial might be harmful. Given that captive breeding programmes are increasingly used to combat worldwide amphibian declines, these programmes must consider the ecology and evolutionary history of the focal species to minimize any maladaptive parental effects.
The prognostic impact of pre-treatment cachexia in resectional surgery for oesophagogastric cancer: a meta-analysis and meta-regression
Authors: Brown Leo R , Sayers Judith , Yule Michael S , Drake Thomas M , Dolan Ross D , McMillan Donald C , Laird Barry J A , Wigmore Stephen J , Skipworth Richard J E
Published: August 2023

Background

Cancer cachexia is not purely an end-stage phenomenon and can influence the outcomes of patients with potentially curable disease. This review examines the effect of pre-treatment cachexia on overall survival, in patients undergoing surgical resection of oesophagogastric cancer.

Methods

A systematic literature search of MEDLINE, EMBASE and Cochrane Library databases was conducted, from January 2000 to May 2022, to identify studies reporting the influence of cachexia on patients undergoing an oesophagogastric resection for cancer with curative intent. Meta-analyses of the primary (overall survival) and secondary (disease-free survival and postoperative mortality) outcomes were performed using random-effects modelling. Meta-regression was used to examine disease stage as a potential confounder.

Results

Ten non-randomized studies, comprising 7186 patients, were eligible for inclusion. The prevalence of pre-treatment cachexia was 35 per cent (95 per cent c.i.: 24–47 per cent). Pooled adjusted hazard ratios showed that cachexia was adversely associated with overall survival (HR 1.46, 95 per cent c.i.: 1.31–1.60, P < 0.001). Meta-analysis of proportions identified decreased overall survival at 1-, 3- and 5-years in cachectic cohorts. Pre-treatment cachexia was not a predictor of disease-free survival and further data are required to establish its influence on postoperative mortality. The proportion of patients with stage III/IV disease was a significant moderator of between-study heterogeneity. Cachexia may have a greater influence on overall survival in studies where more patients have a locally advanced malignancy.

Conclusion

Pre-treatment cachexia adversely influences overall survival following resection of an oesophagogastric malignancy.
Identifying sources of human interictal discharges with travelling wave and white matter propagation
Authors: Withers C Price , Diamond Joshua M , Yang Braden , Snyder Kathryn , Abdollahi Shervin , Sarlls Joelle , Chapeton Julio I , Theodore William H , Zaghloul Kareem A , Inati Sara K
Published: August 2023

Interictal epileptiform discharges have been shown to propagate from focal epileptogenic sources as travelling waves or through more rapid white matter conduction. We hypothesize that both modes of propagation are necessary to explain interictal discharge timing delays. We propose a method that, for the first time, incorporates both propagation modes to identify unique potential sources of interictal activity.

We retrospectively analysed 38 focal epilepsy patients who underwent intracranial EEG recordings and diffusion-weighted imaging for epilepsy surgery evaluation. Interictal discharges were detected and localized to the most likely source based on relative delays in time of arrival across electrodes, incorporating travelling waves and white matter propagation. We assessed the influence of white matter propagation on distance of spread, timing and clinical interpretation of interictal activity. To evaluate accuracy, we compared our source localization results to earliest spiking regions to predict seizure outcomes.

White matter propagation helps to explain the timing delays observed in interictal discharge sequences, underlying rapid and distant propagation. Sources identified based on differences in time of receipt of interictal discharges are often distinct from the leading electrode location. Receipt of activity propagating rapidly via white matter can occur earlier than more local activity propagating via slower cortical travelling waves. In our cohort, our source localization approach was more accurate in predicting seizure outcomes than the leading electrode location. Inclusion of white matter in addition to travelling wave propagation in our model of discharge spread did not improve overall accuracy but allowed for identification of unique and at times distant potential sources of activity, particularly in patients with persistent postoperative seizures.

Since distant white matter propagation can occur more rapidly than local travelling wave propagation, combined modes of propagation within an interictal discharge sequence can decouple the commonly assumed relationship between spike timing and distance from the source. Our findings thus highlight the clinical importance of recognizing the presence of dual modes of propagation during interictal discharges, as this may be a cause of clinical mislocalization.